The authors are thankful to G. Q. Daley for providing the BaF3 and WEHI cells and T. Reya for the MSCV-BCR-ABL-Ires-YFP constructs. The authors are thankful to M. Carroll for providing the patient samples from the CML blast crisis. This study was supported by grants to M.A. from the NCI (1RO1CA155091), the Leukemia Research Foundation and V Foundation, and from the NHLBI (R21HL114074-01).

<ol>
	<li>Daley, G. Q., Van Etten, R. A., Baltimore, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+chronic+myelogenous+leukemia+in+mice+by+the+P210bcr/abl+gene+of+the+Philadelphia+chromosome.">Induction of chronic myelogenous leukemia in mice by the P210bcr/abl gene of the Philadelphia chromosome.</a> Science. 247, 824-830 (1990).</li><li>Druker, B. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+a+selective+inhibitor+of+the+Abl+tyrosine+kinase+on+the+growth+of+Bcr-Abl+positive+cells.">Effects of a selective inhibitor of the Abl tyrosine kinase on the growth of Bcr-Abl positive cells.</a> Nature Medicine. 2, 561-566 (1996).</li><li>Mahon, F. X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Discontinuation+of+imatinib+in+patients+with+chronic+myeloid+leukaemia+who+have+maintained+complete+molecular+remission+for+at+least+2+years:+the+prospective,+multicentre+Stop+Imatinib+(STIM)+trial.">Discontinuation of imatinib in patients with chronic myeloid leukaemia who have maintained complete molecular remission for at least 2 years: the prospective, multicentre Stop Imatinib (STIM) trial.</a> Lancet Oncology. 11, 1029-1035 (2010).</li><li>O'Hare, T., Zabriskie, M. S., Eiring, A. M., Deininger, M. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pushing+the+limits+of+targeted+therapy+in+chronic+myeloid+leukaemia.">Pushing the limits of targeted therapy in chronic myeloid leukaemia.</a> Nature Reviews Cancer. 12, 513-526 (2012).</li><li>Rousselot, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imatinib+mesylate+discontinuation+in+patients+with+chronic+myelogenous+leukemia+in+complete+molecular+remission+for+more+than+2+years.">Imatinib mesylate discontinuation in patients with chronic myelogenous leukemia in complete molecular remission for more than 2 years.</a> Blood. 109, 58-60 (2007).</li><li>Krause, D. S., Van Etten, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tyrosine+kinases+as+targets+for+cancer+therapy.">Tyrosine kinases as targets for cancer therapy.</a> The New England Journal of Medicine. 353, 172-187 (2005).</li><li>Sharma, S. V., Settleman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exploiting+the+balance+between+life+and+death:+targeted+cancer+therapy+and+"oncogenic+shock".">Exploiting the balance between life and death: targeted cancer therapy and "oncogenic shock".</a> Biochemical Pharmacology. 80, 666-673 (2010).</li><li>Sharma, S. V., Settleman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oncogene+addiction:+setting+the+stage+for+molecularly+targeted+cancer+therapy.">Oncogene addiction: setting the stage for molecularly targeted cancer therapy.</a> Genes &amp; Development. 21, 3214-3231 (2007).</li><li>Weinstein, I. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cancer.+Addiction+to+oncogenes--the+Achilles+heal+of+cancer.">Cancer. Addiction to oncogenes--the Achilles heal of cancer.</a> Science. 297, 63-64 (2002).</li><li>Corbin, A. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+chronic+myeloid+leukemia+stem+cells+are+insensitive+to+imatinib+despite+inhibition+of+BCR-ABL+activity.">Human chronic myeloid leukemia stem cells are insensitive to imatinib despite inhibition of BCR-ABL activity.</a> The Journal of Clinical Investigation. 121, 396-409 (2011).</li><li>Straussman, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumour+micro-environment+elicits+innate+resistance+to+RAF+inhibitors+through+HGF+secretion.">Tumour micro-environment elicits innate resistance to RAF inhibitors through HGF secretion.</a> Nature. 487, 500-504 (2012).</li><li>Wilson, T. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Widespread+potential+for+growth-factor-driven+resistance+to+anticancer+kinase+inhibitors.">Widespread potential for growth-factor-driven resistance to anticancer kinase inhibitors.</a> Nature. 487, 505-509 (2012).</li><li>Kesarwani, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+c-FOS+and+DUSP1+abrogates+intrinsic+resistance+to+tyrosine-kinase+inhibitor+therapy+in+BCR-ABL-induced+leukemia.">Targeting c-FOS and DUSP1 abrogates intrinsic resistance to tyrosine-kinase inhibitor therapy in BCR-ABL-induced leukemia.</a> Nature Medicine. 23, 472-482 (2017).</li><li>Zhang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=c-fos+regulates+neuronal+excitability+and+survival.">c-fos regulates neuronal excitability and survival.</a> Nature Genetics. 30, 416-420 (2002).</li><li>Dorfman, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Disruption+of+the+erp/mkp-1+gene+does+not+affect+mouse+development:+normal+MAP+kinase+activity+in+ERP/MKP-1-deficient+fibroblasts.">Disruption of the erp/mkp-1 gene does not affect mouse development: normal MAP kinase activity in ERP/MKP-1-deficient fibroblasts.</a> Oncogene. 13, 925-931 (1996).</li><li>Padhye, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorocurcumins+as+cyclooxygenase-2+inhibitor:+molecular+docking,+pharmacokinetics+and+tissue+distribution+in+mice.">Fluorocurcumins as cyclooxygenase-2 inhibitor: molecular docking, pharmacokinetics and tissue distribution in mice.</a> Pharmaceutical Research. 26, 2438-2445 (2009).</li><li>Molina, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+chemical+screening+reveals+an+inhibitor+of+Dusp6+that+expands+cardiac+cell+lineages.">Zebrafish chemical screening reveals an inhibitor of Dusp6 that expands cardiac cell lineages.</a> Nature Chemical Biology. 5, 680-687 (2009).</li><li>Zhang, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effective+targeting+of+quiescent+chronic+myelogenous+leukemia+stem+cells+by+histone+deacetylase+inhibitors+in+combination+with+imatinib+mesylate.">Effective targeting of quiescent chronic myelogenous leukemia stem cells by histone deacetylase inhibitors in combination with imatinib mesylate.</a> Cancer Cell. 17, 427-442 (2010).</li><li>Koschmieder, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inducible+chronic+phase+of+myeloid+leukemia+with+expansion+of+hematopoietic+stem+cells+in+a+transgenic+model+of+BCR-ABL+leukemogenesis.">Inducible chronic phase of myeloid leukemia with expansion of hematopoietic stem cells in a transgenic model of BCR-ABL leukemogenesis.</a> Blood. 105, 324-334 (2005).</li><li>Abraham, S. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dual+targeting+of+p53+and+c-MYC+selectively+eliminates+leukaemic+stem+cells.">Dual targeting of p53 and c-MYC selectively eliminates leukaemic stem cells.</a> Nature. 534, 341-346 (2016).</li><li>Li, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activation+of+p53+by+SIRT1+inhibition+enhances+elimination+of+CML+leukemia+stem+cells+in+combination+with+imatinib.">Activation of p53 by SIRT1 inhibition enhances elimination of CML leukemia stem cells in combination with imatinib.</a> Cancer Cell. 21, 266-281 (2012).</li><li>. Qiagen-miRNAeasy kit Available from: <a target="_blank" href="https://www.qiagen.com/us/shop/sample-technologies/rna/mirna/mirneasy-mini-kit/#resources">https://www.qiagen.com/us/shop/sample-technologies/rna/mirna/mirneasy-mini-kit/#resources</a> (2018)</li><li>. DNA-free DNA removal kit Available from: <a target="_blank" href="https://www.thermofisher.com/order/catalog/product/AM1906?gclid=EAIaIQobChMIg4D-_ZvC2wIVx5-zCh00Cg8fEAAYASAAEgIv6vD_BwE&amp;s_kwcid=AL!3652!3!264318446624!b!!g!!&amp;ef_id=V7SO5AAAAck3ba89:20180607185004:s">https://www.thermofisher.com/order/catalog/product/AM1906?gclid=EAIaIQobChMIg4D-_ZvC2wIVx5-zCh00Cg8fEAAYASAAEgIv6vD_BwE&amp;s_kwcid=AL!3652!3!264318446624!b!!g!!&amp;ef_id=V7SO5AAAAck3ba89:20180607185004:s</a> (2018)</li><li>. SuperScript&#8482; III First-Strand Synthesis System Available from: <a target="_blank" href="https://www.thermofisher.com/order/catalog/product/18080051">https://www.thermofisher.com/order/catalog/product/18080051</a> (2018)</li><li>. Human Long Term Culture Initiating Cell Itc-ic Assay Available from: <a target="_blank" href="https://www.stemcell.com/human-long-term-culture-initiating-cell-ltc-ic-assay.html">https://www.stemcell.com/human-long-term-culture-initiating-cell-ltc-ic-assay.html</a> (2018)</li><li>Abarrategi, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+the+human+bone+marrow+niche+in+mice:+From+host+bone+marrow+engraftment+to+bioengineering+approaches.">Modeling the human bone marrow niche in mice: From host bone marrow engraftment to bioengineering approaches.</a> Journal of Experimental Medicine. 215, 729-743 (2018).</li><li>Kesarwani, M., Huber, E., Kincaid, Z., Azam, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+screening+and+validation+of+resistant+mutations+against+kinase+inhibitors.">A method for screening and validation of resistant mutations against kinase inhibitors.</a> Journal of Visualized Experiments. , (2014).</li></ol>

The authors have nothing to disclose.

For the bulk of cancer cells, the therapeutic response to TKI is mediated by a blockade of tyrosine-kinase-oncoprotein signals to which the tumor is addicted. However, relatively little is known about how a minority of cancer cells contributing to MRD escape the oncogene dependence and therapy4. Recent studies revealed that growth factor signaling mediates drug resistance in both leukemia and solid organ tumors. This suggests that various molecular mechanisms might underlie intrinsic resistance<su...

Constitutive tyrosine kinase activity of BCR-ABL1 fusion oncogene causes CML, which provides a rationale to target the kinase activity by small molecule inhibitors. The success of TKIs in treating CML patients revolutionized the concept of targeted therapy1,2. Subsequently, anti-kinase therapy as precision medicine was developed for several other malignancies, including solid tumors. So far, more than thirty kinase inhibitors have been approved by the United State FDA for treating various malignancies. While TKI treatment is very effective in suppressing the disease, it is not curative. Besides, a small population of cancer cells persists during the treatment: the MRD3,4,5. Even patients who showed complete remission are left with MRD, which eventually results in relapse if not continuously suppressed. Therefore, the eradication of MRD cells is needed to achieve a durable or curative response. CML represents a valuable paradigm for defining the concept of precision medicine, mechanisms of oncogenesis, rational target-directed therapeutics, disease progression, and drug resistance. However, even today, the mechanism driving TKI-induced cell death in cancer cells is not fully understood, nor why MRD cells (comprised of leukemic stem cells [LSCs]) are intrinsically resistant to TKIs4,6. Nonetheless, the phenomenon of &#34;oncogene dependence&#34; to mutant kinase oncoprotein is implicated in TKI efficacy where the acute inhibition of targeted oncogene by TKIs causes an oncogenic shock that leads to a massive proapoptotic response or quiescence in cell context-dependent manner6,7,8,9. However, the mechanistic underpinning of oncogene dependence is lacking. Recent studies have implicated that growth factor signaling abrogates oncogene dependence and consequently confers resistance to TKI therapy10,11,12. Therefore, to gain insight into the mechanism of oncogene dependence, we performed whole-genome expression profiling from BCR-ABL1 addicted and nonaddicted cells (grown with growth factors), which revealed that c-Fos and Dusp1 are critical mediators of oncogene addiction13. The genetic deletion of c-Fos and Dusp1 is synthetic lethal to BCR-ABL1-expressing cells and the mice used in the experiment did not develop leukemia. Moreover, the inhibition of c-Fos and DUSP1 by small molecule inhibitors cured BCR-ABL1-induced CML in mice. The results show that the expression levels of c-Fos and Dusp1 define the apoptotic threshold in cancer cells, such that lower levels confer drug sensitivity while higher levels cause resistance to therapy13.
To identify the genes driving the oncogene dependence, we performed several whole-genome expression profiling experiments in the presence of growth factor and a TKI (imatinib) using both mouse- and CML patient-derived cells (K562). These data were analyzed in parallel with CML patient data sets obtained from CD34+ hematopoietic stem cells before and after treatment with imatinib. This analysis revealed three genes (a transcription factor [c-Fos], dual specificity phosphatase 1 [Dusp1], and an RNA-binding protein [Zfp36]) which are commonly upregulated in TKI-resistant cells. To validate the significance of these genes in conferring drug resistance, we carried out step-by-step in vitro and in vivo analysis. The expression levels of these genes were confirmed by real-time qPCR (RT-qPCR) and western blotting in drug-resistant cells. Further, cDNA overexpression and knockdown by shRNA hairpins of c-Fos, Dusp1, and Zfp36 revealed that elevated c-Fos and Dusp1 expressions are sufficient and necessary to confer TKI resistance. Therefore, we performed an in vivo validation using mouse models with c-Fos and Dusp1 only. For the genetic validation of c-Fos and Dusp1, we created ROSACreERT-inducible c-Fosfl/fl mice (conditional knockout)14 and crossed them with Dusp1-/- (straight knockout)15 to make ROSACreERT2-c-Fosfl/flDusp1-/- double-transgenic mice. Bone marrow-derived c-Kit+ cells (from c-Fosfl/fl-, Dusp1-/--, and c-Fosfl/flDusp1-/-) expressing BCR-ABL1 were analyzed in vitro in a colony-forming unit (CFU) assay, and in vivo by bone marrow transplantation in lethally irradiated mice, to test the requirement of c-Fos and Dusp1 alone or together in leukemia development. Likewise, the chemical inhibitions of c-Fos by DFC (difluorinated curcumin)16 and Dusp1 by BCI (benzylidene-3-(cyclohexylamino)-2,3-dihydro-1H-inden-1-one)17 were tested in vitro and in vivo using BCR-ABL1-expressing, bone marrow-derived c-Kit+ cells from the wild-type (WT) mouse. To confirm the requirement of c-Fos and Dusp1 in leukemic stem cells, we utilized a CML mouse model where BCR-ABL1 was specifically induced in its stem cells by doxycycline (Tet-transactivator expresses under murine stem cell leukemia (SCL) gene 3&#39; enhancer regulation)18,19. We used bone marrow Lin-Sca+c-Kit+ (LSK) cells from these mice in an in vivo transplant assay. Furthermore, we established phopsho-p38 levels and the expression of IL-6 as pharmaco-dynamic biomarkers for Dusp1 and c-Fos inhibition, respectively, in vivo. Finally, to extend the study for human relevance, patient-derived CD34+ cells (equivalent to the c-Kit+ cells from mice) were subjected to long-term in vitro culture-initiating cell assays (LTCIC) and an in vivo humanized mouse model of CML20,21. The immunodeficient mice were transplanted with CML CD34+ cells, followed by drug treatment and analysis of human leukemic cell survival.
In this project, we develop methods for target identification and validations using both genetic and chemical tools, using different preclinical models. These methods can be successfully applied to validate other targets developing chemical modalities for therapeutic development.

<table border="0" cellpadding="0" cellspacing="0" style="width:948px;" width="946">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:424px;">Biological Materials</td>
			<td style="width:247px;"></td>
			<td style="width:147px;"></td>
			<td style="width:131px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">RPMI</td>
			<td>Cellgro (corning)</td>
			<td>15-040-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DMEM</td>
			<td>Cellgro (corning)</td>
			<td>15-013-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">IMDM</td>
			<td>Cellgro (corning)</td>
			<td>15-016-CVR</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">RetroNectin Recombinant Human Fibronectin Fragment</td>
			<td>Takara</td>
			<td>T100B</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MethoCult GF M3434 (Methylcellulose for Mouse CFU)</td>
			<td>Stem Cell</td>
			<td>3434</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MethoCult H4434 Classic (Methylcellulose for Human CFU)</td>
			<td>Stem Cell</td>
			<td>4434</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">4-Hydroxytamoxifen</td>
			<td>Sigma</td>
			<td>H6278</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Recombinant Murine SCF</td>
			<td>Prospec</td>
			<td>CYT-275</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Recombinant Murine Flt3-Ligand</td>
			<td>Prospec</td>
			<td>CYT-340</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Recombinant Murine IL-6</td>
			<td>Prospec</td>
			<td>CYT-350</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Recombinant Murine IL-7</td>
			<td>Peprotech</td>
			<td>217-17</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DFC</td>
			<td>LKT Laboratories Inc.</td>
			<td>D3420</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">BCI</td>
			<td>Chemzon Scientific</td>
			<td>NZ-06-195</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Imatinib</td>
			<td>LC Laboratory</td>
			<td>I-5508</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Curcumin</td>
			<td>Sigma</td>
			<td>458-37-7</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">NDGA</td>
			<td>Sigma</td>
			<td>500-38-9</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Penn/Strep</td>
			<td>Cellgro (corning)</td>
			<td>30-002-CI</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">FBS</td>
			<td>Atlanta biological</td>
			<td>S11150</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Trypsin EDTA 1X</td>
			<td>Cellgro (corning)</td>
			<td>25-052-CI</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">1XPBS</td>
			<td>Cellgro (corning)</td>
			<td>21-040-CV</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">L-Glutamine</td>
			<td>Cellgro (corning)</td>
			<td>25-005-CL</td>
			<td style="width:131px;">5mg/ml stock in water</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Puromycin</td>
			<td>Gibco (life technologies)</td>
			<td>A11138-03</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">HEPES</td>
			<td>Sigma</td>
			<td>H7006</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Na2HPO4.7H2O</td>
			<td>Sigma</td>
			<td>S9390</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Protamine sulfate</td>
			<td>Sigma</td>
			<td>P3369</td>
			<td style="width:131px;">5mg/ml stock in water</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Trypan Blue solution (0.4%)</td>
			<td>Sigma</td>
			<td>T8154</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DMSO</td>
			<td>Cellgro (corning)</td>
			<td>25-950-CQC</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">WST-1</td>
			<td>Roche</td>
			<td>11644807001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">0.45uM acro disc filter</td>
			<td>PALL</td>
			<td>2016-10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">70um nylon cell stariner</td>
			<td>Becton Dickinson</td>
			<td>352350</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">FICOL (Histopaque 1083) (polysucrose)</td>
			<td>Simga</td>
			<td>1083</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PBS</td>
			<td>Corning</td>
			<td>21040CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">LS Columns</td>
			<td>Miltenyi</td>
			<td>130-042-401</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Protease Inhibitor Cocktail</td>
			<td>Roche</td>
			<td>CO-RO</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Phosphatase Inhibitor Cocktail 2</td>
			<td>Sigma</td>
			<td>P5762</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Nitrocullulose Membrane</td>
			<td>Bio-Rad</td>
			<td>1620115</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:424px;">SuperSignal West Dura Extended Duration Substrate ( chemiluminiscence substrate)</td>
			<td>Thermo Scientific</td>
			<td>34075</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CD5</td>
			<td>eBioscience</td>
			<td>13-0051-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CD11b</td>
			<td>eBioscience</td>
			<td>13-0112-75</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CD45R (B220)</td>
			<td>BD biosciences</td>
			<td>553092</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CD45.1-FITC</td>
			<td>eBioscience</td>
			<td>11-0453-85</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CD45.2-PE</td>
			<td>eBioscience</td>
			<td>12-0454-83</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">hCD45-FITC</td>
			<td>BD Biosciences</td>
			<td>555482</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Anti-Biotin-FITC</td>
			<td>Miltenyi</td>
			<td>130-090-857&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Anti-7-4</td>
			<td>eBioscience</td>
			<td>MA5-16539</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Anti-Gr-1 (Ly-6G/c)</td>
			<td>eBioscience</td>
			<td>13-5931-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Anti-Ter-119</td>
			<td>eBioscience</td>
			<td>13-5921-75</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ly-6 A/E (Sca1) PE Cy7</td>
			<td>BD&#160;</td>
			<td>558612</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CD117 APC&#160;</td>
			<td>BD&#160;</td>
			<td>553356</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">BD Pharm Lyse</td>
			<td>BD&#160;</td>
			<td>555899</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">BD Cytofix/Cytoperm (Fixing and permeabilization solution)</td>
			<td>BD&#160;</td>
			<td>554714</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:424px;">BD Perm/Wash&#160; (permeabilization and wash solution for phospho flow)</td>
			<td>BD&#160;</td>
			<td>554723</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">phospho p38</td>
			<td>Cell Signaling Technologies</td>
			<td>4511S</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">total p38</td>
			<td>Cell Signaling Technologies</td>
			<td>9212</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mouse IgG control</td>
			<td>BD&#160;</td>
			<td>554121</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Alexa Flour 488 conjugated&#160;</td>
			<td>Invitrogen</td>
			<td>A-11034</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Calcium Chloride</td>
			<td>Invitrogen</td>
			<td>K278001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">2X HBS</td>
			<td>Invitrogen</td>
			<td>K278002</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">EDTA</td>
			<td>Ambion</td>
			<td>AM9261</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">BSA</td>
			<td>Sigma</td>
			<td>A7906</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Blood Capillary Tubes</td>
			<td>Fisher</td>
			<td>22-260-950</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Blood Collection Tube</td>
			<td>Giene Bio-One</td>
			<td>450480</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Newborn Calf Serum</td>
			<td>Atlanta biological</td>
			<td>S11295</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Erythropoiein</td>
			<td>Amgen</td>
			<td>5513-267-10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">human SCF</td>
			<td>Prospec</td>
			<td>CYT-255</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Human IL-3</td>
			<td>Prospec</td>
			<td>CYT-210</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">G-SCF</td>
			<td>Prospec</td>
			<td>CYT-220</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">GM-CSF</td>
			<td>Prospec</td>
			<td>CYT-221</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MyeloCult (media for LTCIC assay)</td>
			<td>Stem Cell Technologies</td>
			<td>5100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hydrocortisone Sodium Hemisuccinate</td>
			<td>Stem Cell Technologies</td>
			<td>7904</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MEM alpha</td>
			<td>Gibco</td>
			<td>12561-056</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">1/2cc Lo-Dose u-100 insulin syringe 28 G1/2</td>
			<td>Becton Dickinson</td>
			<td>329461</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mortor pestle</td>
			<td>Coor tek&#160;</td>
			<td>60316 and 60317</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Isoflorane (Isothesia TM)</td>
			<td>Butler Schien</td>
			<td>29405</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">SOC</td>
			<td>New England Biolabs</td>
			<td>B90920s</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Ampicillin</td>
			<td>Sigma</td>
			<td>A0166</td>
			<td style="width:131px;">100mg/ml stock in water</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bacto agar (agar)</td>
			<td>Difco</td>
			<td>214050</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Terrific broth</td>
			<td>Becton Dickinson</td>
			<td>243820</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Agarose</td>
			<td>Genemate</td>
			<td>E-3119-500</td>
			<td></td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;">Doxycycline chow</td>
			<td>TestDiet.com</td>
			<td>52662</td>
			<td style="width:131px;">modified RMH1500, Autoclavable 5LK8&#160; with 0.0625% Doxycycline&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Tamoxifen</td>
			<td>Sigma</td>
			<td>T5648</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Iodonitrotetrazolium chloride&#160;</td>
			<td>Sigma</td>
			<td>I10406</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Kits</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dneasy Blood &#38; tissue kit</td>
			<td>Qiagen</td>
			<td>69506</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">GoTaq Green (taq polymerase with Green loadign dye)</td>
			<td>Promega</td>
			<td>M1722</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">miRNeasy Mini Kit&#160; (RNA isolation kit)</td>
			<td>Qiagen</td>
			<td>217084</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DNA Free Dnase Kit (DNAse treatment for RT PCR)</td>
			<td>Ambion, Life Technologies</td>
			<td>AM1906</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:424px;">Superscript III First Strand Synthesis (reverse transcriptase for cDNA synthesis)</td>
			<td>Invitrogen</td>
			<td>18080051</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:424px;">SYBR Green (taq polymerase mix with green interchalating dye for qPCR)</td>
			<td>Bio-Rad</td>
			<td>1725270</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CD117 MicroBead Kit</td>
			<td>Miltenyi</td>
			<td>130-091-224</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Human Long-Term Culture Initiating Cell Assay</td>
			<td>Stemp Cell Technologies</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Instruments</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">NAPCO series 8000 WJ CO2 incubator</td>
			<td>Thermo scientific</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Swing bucket rotor cetrifuge 5810R</td>
			<td>Eppendorf</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">TC-10 automated cell counter</td>
			<td>Bio-RAD</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">C-1000 Thermal cycler</td>
			<td>Bio-RAD</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mastercycler Real Plex 2</td>
			<td>Eppendorf</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:424px;">ChemiDoc Imaging System (imaging system for gels and western blots)</td>
			<td>Bio-RAD</td>
			<td>17001401</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hemavet ( boold counter)</td>
			<td>Drew-Scientific</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">LSR II ( FACS analyzer)</td>
			<td>BD&#160;</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fortessa I ( FACS analyzer)</td>
			<td>BD&#160;</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">FACSAriaII ( FACS Sorter)</td>
			<td>BD&#160;</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Magnet Stand</td>
			<td>Miltenyi</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Irradiator</td>
			<td style="width:247px;">&#160;J.L. Shepherd and Associates, San Fernando CA</td>
			<td>Mark I Model 68A</td>
			<td>source Cs 137</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mice</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">ROSACreERT2</td>
			<td>Jackson Laboratory</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Scl-tTA&#160;</td>
			<td>Dr. Claudia Huettner&#8217;s lab</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">BoyJ&#160;</td>
			<td>mouse core facility at CCHMC</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">C57Bl/6&#160;</td>
			<td>Jackson Laboratory</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">NSGS</td>
			<td>mouse core facility at CCHMC</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;">ROSACreERT2/c-Fosfl/fl Dusp1-/-&#160;</td>
			<td>Made in house</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">ROSACreERT2/c-Fosfl/fl</td>
			<td>Made in house</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cells</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">BaF3</td>
			<td style="width:247px;">Gift from George Daley, Harvard Medical School, Boston</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">WEHI</td>
			<td style="width:247px;">Gift from George Daley, Harvard Medical School, Boston</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">CML-CD34+ and Normal CD34+ cells</td>
			<td style="width:247px;">University Hospital, University of Cincinnati</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

methods for evaluating the role of c-fos and dusp1 in oncogene dependence

The demonstration of tyrosine kinase inhibitors (TKIs) in treating chronic myeloid leukemia (CML) has heralded a new era in cancer therapeutics. However, a small population of cells does not respond to TKI treatment, resulting in minimal residual disease (MRD); even the most potent TKIs fail to eradicate these cells. These MRD cells serve as a reservoir to develop resistance to therapy. Why TKI treatment is ineffective against MRD cells is not known. Growth factor signaling is implicated in supporting the survival of MRD cells during TKI treatment, but a mechanistic understanding is lacking. Recent studies demonstrated that an elevated c-Fos and Dusp1 expression as a result of convergent oncogenic and growth factor signaling in MRD cells mediate TKI resistance. The genetic and chemical inhibition of c-Fos and Dusp1 renders CML exquisitely sensitive to TKIs and cures CML in both genetic and humanized mouse models. We identified these target genes using multiple microarrays from TKI-sensitive and -resistant cells. Here, we provide methods for target validation using in vitro and in vivo mouse models. These methods can easily be applied to any target for genetic validation and therapeutic development.

Oncogene addiction has been implicated in the therapeutic efficacy of TKIs. However, the mechanisms driving the oncogene dependence are not understood. We performed multiple unbiased gene expression analyses to identify the genetic component involved in orchestrating the addiction. These analyses revealed the upregulation of three genes, c-Fos, Dusp1, and Zfp36, in cancer cells that are not dependent on oncogenic signaling for survival and, thus, are insensitive to TKI treatment. The down...

Watch this Scientific Journal Video about Methods for Evaluating the Role of c-Fos and Dusp1 in Oncogene Dependence at JoVE.com

Methods for Evaluating the Role of c-Fos and Dusp1 in Oncogene Dependence

Here, we describe protocols for the genetic and chemical validation of c-Fos and Dusp1 as a drug target in leukemia using in vitro and in vivo genetic and humanized mouse models. This method can be applied to any target for genetic validation and therapeutic development.

The demonstration of tyrosine kinase inhibitors (TKIs) in treating chronic myeloid leukemia (CML) has heralded a new era in cancer therapeutics. However, ...

methods-for-evaluating-role-c-fos-dusp1-oncogene

Research

JoVE Journal

Cancer Research

8.2K Views.  Cincinnati Children's Hospital Medical Center. Here, we describe protocols for the genetic and chemical validation of c-Fos and Dusp1 as a drug target in leukemia using in vitro and in vivo genetic and humanized mouse models. This method can be applied to any target for genetic validation and therapeutic development.

Video: Methods for Evaluating the Role of c-Fos and Dusp1 in Oncogene Dependence

Coculture Assays to Study Macrophage and Microglia Stimulation of Glioblastoma Invasion

Glioblastoma multiforme (grade IV glioma) is a very aggressive human cancer with a median survival of 1 year post diagnosis. Despite the increased understanding of the molecular events that give rise to glioblastomas, this cancer still remains highly refractory to conventional treatment. Surgical resection of high grade brain tumors is rarely complete due to the highly infiltrative nature of glioblastoma cells. Therapeutic approaches which attenuate glioblastoma cell invasion therefore is an attractive option. Our laboratory and others have shown that tumor associated macrophages and microglia (resident brain macrophages) strongly stimulate glioblastoma invasion. The protocol described in this paper is used to model glioblastoma-macrophage/microglia interaction using in vitro culture assays. This approach can greatly facilitate the development and/or discovery of drugs that disrupt the communication with the macrophages that enables this malignant behavior. We have established two robust coculture invasion assays where microglia/macrophages stimulate glioma cell invasion by 5 - 10 fold. Glioblastoma cells labelled with a fluorescent marker or constitutively expressing a fluorescent protein are plated without and with macrophages/microglia on matrix-coated polycarbonate chamber inserts or embedded in a three dimensional matrix. Cell invasion is assessed by using fluorescent microscopy to image and count only invasive cells on the underside of the filter. Using these assays, several pharmacological inhibitors (JNJ-28312141, PLX3397, Gefitinib, and Semapimod), have been identified which block macrophage/microglia stimulated glioblastoma invasion.

Understanding the malignant behavior of cancer requires creating accurate models of how tumor cells interact with components of the tumor microenvironment, such as macrophages. Here we describe two methods to study glioblastoma cell interaction with tumor associated macrophages and microglia where the effect on glioblastoma invasion is assessed.

Glioblastoma multiforme (grade IV glioma) is a very aggressive human cancer with a median survival of 1 year post diagnosis. Despite the increased ...

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics

Drosophila melanogaster has emerged as a powerful experimental system for functional and mechanistic studies of tumor development and progression in the context of a whole organism. Sophisticated techniques to generate genetic mosaics facilitate induction of visually marked, genetically defined clones surrounded by normal tissue. The clones can be analyzed through diverse molecular, cellular and omics approaches. This study describes how to generate fluorescently labeled clonal tumors of varying malignancy in the eye/antennal imaginal discs (EAD) of Drosophila larvae using the Mosaic Analysis with a Repressible Cell Marker (MARCM) technique. It describes procedures how to recover the mosaic EAD and brain from the larvae and how to process them for simultaneous imaging of fluorescent transgenic reporters and antibody staining. To facilitate molecular characterization of the mosaic tissue, we describe a protocol for isolation of total RNA from the EAD. The dissection procedure is suitable to recover EAD and brains from any larval stage. The fixation and staining protocol for imaginal discs works with a number of transgenic reporters and antibodies that recognize Drosophila proteins. The protocol for RNA isolation can be applied to various larval organs, whole larvae, and adult flies. Total RNA can be used for profiling of gene expression changes using candidate or genome-wide approaches. Finally, we detail a method for quantifying invasiveness of the clonal tumors. Although this method has limited use, its underlying concept is broadly applicable to other quantitative studies where cognitive bias must be avoided.

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics

This protocol demonstrates how to generate fluorescently marked, genetically defined clonal tumors in the Drosophila eye/antennal imaginal discs (EAD). It describes how to dissect the EAD and brain from the third instar larvae and how to process them to visualize and quantify gene expression changes and tumor invasiveness.

Drosophila melanogaster has emerged as a powerful experimental system for functional and mechanistic studies of tumor development and progression in the ...

Evaluating In Vitro DNA Damage Using Comet Assay

DNA damage is a common phenomenon for each cell during its lifespan, and is defined as an alteration of the chemical structure of genomic DNA. Cancer therapies, such as radio- and chemotherapy, introduce enormous amount of additional DNA damage, leading to cell cycle arrest and apoptosis to limit cancer progression. Quantitative assessment of DNA damage during experimental cancer therapy is a key step to justify the effectiveness of a genotoxic agent. In this study, we focus on a single cell electrophoresis assay, also known as the comet assay, which can quantify single and double-strand DNA breaks in vitro. The comet assay is a DNA damage quantification method that is efficient and easy to perform, and has low time/budget demands and high reproducibility. Here, we highlight the utility of the comet assay for a preclinical study by evaluating the genotoxic effect of olaparib/temozolomide combination therapy to U251 glioma cells.

Evaluating In Vitro DNA Damage Using Comet Assay

The comet assay is an efficient method to detect DNA damage including single and double-stranded DNA breaks. We describe alkaline and neutral comet assays to measure DNA damage in cancer cells to evaluate the therapeutic effect of chemotherapy.

DNA damage is a common phenomenon for each cell during its lifespan, and is defined as an alteration of the chemical structure of genomic DNA. Cancer ...

Two-dimensional Gel Electrophoresis Coupled with Mass Spectrometry Methods for an Analysis of Human Pituitary Adenoma Tissue Proteome

Human pituitary adenoma (PA) is a common tumor that occurs in the human pituitary gland in the hypothalamus-pituitary-targeted organ axis systems, and may be classified as either clinically functional or nonfunctional PA (FPA and NFPA). NFPA is difficult for early stage diagnosis and therapy due to barely elevating hormones in the blood compared to FPA. Our long-term goal is to use proteomics methods to discover reliable biomarkers for clarification of PA molecular mechanisms and recognition of effective diagnostic, prognostic markers and therapeutic targets. Effective two-dimensional gel electrophoresis (2DE) coupled with mass spectrometry (MS) methods were presented here to analyze human PA proteomes, including preparation of samples, 2D gel electrophoresis, protein visualization, image analysis, in-gel trypsin digestion, peptide mass fingerprint (PMF), and tandem mass spectrometry (MS/MS). 2-Dimensional gel electrophoresis matrix-assisted laser desorption/ionization mass spectrometry PMF (2DE-MALDI MS PMF), 2DE-MALDI MS/MS, and 2DE-liquid chromatography (LC) MS/MS procedures have been successfully applied in an analysis of NFPA proteome. With the use of a high-sensitivity mass spectrometer, many proteins were identified with the 2DE-LC-MS/MS method in each 2D gel spot in an analysis of complex PA tissue to maximize the coverage of human PA proteome.

Here, we present a two-dimensional gel electrophoresis (2DE) coupled with mass spectrometry (MS) to separate and identify human pituitary adenoma tissue proteome, which presents a good and reproducible 2DE pattern. Many proteins are observed in each 2DE spot when analyzing complex cancer proteome with the use of high-sensitivity MS.

Human pituitary adenoma (PA) is a common tumor that occurs in the human pituitary gland in the hypothalamus-pituitary-targeted organ axis systems, and may ...

Evaluating the Role of Mitochondrial Function in Cancer-related Fatigue

Fatigue is a common and debilitating condition that affects most cancer patients. To date, fatigue remains poorly characterized with no diagnostic test to objectively measure the severity of this condition. Here we describe an optimized method for assessing mitochondrial function of PBMCs collected from fatigued cancer patients. Using a compact extracellular flux system and sequential injection of respiratory inhibitors, we examined PBMC mitochondrial functional status by measuring basal mitochondrial respiration, spare respiratory capacity, and energy phenotype, which describes the preferred energy pathway to respond to stress. Fresh PBMCs are readily available in the clinical setting using standard phlebotomy. The entire assay described in this protocol can be completed in less than 4 hours without the involvement of complex biochemical techniques. Additionally, we describe a normalization method that is necessary for obtaining reproducible data. The simple procedure and normalization methods presented allow for repeated sample collection from the same patient and generation of reproducible data that can be compared between time points to evaluate potential treatment effects.

Our goal was to develop a practical protocol to evaluate mitochondrial dysfunction associated with fatigue in cancer patients. This innovative protocol is optimized for clinical use involving only standard phlebotomy and basic laboratory procedures.

Fatigue is a common and debilitating condition that affects most cancer patients. To date, fatigue remains poorly characterized with no diagnostic test to ...

3-D Cell Culture System for Studying Invasion and Evaluating Therapeutics in Bladder Cancer

Bladder cancer is a significant health problem. It is estimated that more than 16,000 people will die this year in the United States from bladder cancer. While 75% of bladder cancers are non-invasive and unlikely to metastasize, about 25% progress to an invasive growth pattern. Up to half of the patients with invasive cancers will develop lethal metastatic relapse. Thus, understanding the mechanism of invasive progression in bladder cancer is crucial to predict patient outcomes and prevent lethal metastases. In this article, we present a three-dimensional cancer invasion model which allows incorporation of tumor cells and stromal components to mimic in vivo conditions occurring in the bladder tumor microenvironment. This model provides the opportunity to observe the invasive process in real time using time-lapse imaging, interrogate the molecular pathways involved using confocal immunofluorescent imaging and screen compounds with the potential to block invasion. While this protocol focuses on bladder cancer, it is likely that similar methods could be used to examine invasion and motility in other tumor types as well.

The processes governing bladder cancer invasion represent opportunities for biomarker and therapeutic development. Here we present a bladder cancer invasion model which incorporates 3-D culture of tumor spheroids, time-lapse imaging and confocal microscopy. This technique is useful for defining the features of the invasive process and for screening therapeutic agents.

Bladder cancer is a significant health problem. It is estimated that more than 16,000 people will die this year in the United States from bladder cancer. ...

Characterize Disease-related Mutants of RAF Family Kinases by Using a Set of Practical and Feasible Methods

The rapidly accelerated fibrosarcoma (RAF) family kinases play a central role in cell biology and their dysfunction leads to cancers and developmental disorders. A characterization of disease-related RAF mutants will help us select appropriate therapeutic strategies for treating these diseases. Recent studies have shown that RAF family kinases have both catalytic and allosteric activities, which are tightly regulated by dimerization. Here, we constructed a set of practical and feasible methods to determine the catalytic and allosteric activities and the relative dimer affinity/stability of RAF family kinases and their mutants. Firstly, we amended the classical in vitro kinase assay by reducing the detergent concentration in buffers, utilizing a gentle quick wash procedure, and employing a glutathione S-transferase (GST) fusion to prevent RAF dimers from dissociating during purification. This enables us to measure the catalytic activity of constitutively active RAF mutants appropriately. Secondly, we developed a novel RAF co-activation assay to evaluate the allosteric activity of kinase-dead RAF mutants by using N-terminal truncated RAF proteins, eliminating the requirement of active Ras in current protocols and thereby achieving a higher sensitivity. Lastly, we generated a unique complementary split luciferase assay to quantitatively measure the relative dimer affinity/stability of various RAF mutants, which is more reliable and sensitive compared to the traditional co-immunoprecipitation assay. In summary, these methods have the following advantages: (1) user-friendly; (2) able to carry out effectively without advanced equipment; (3) cost-effective; (4) highly sensitive and reproducible.

In this article, we presented a set of practical and feasible methods for characterizing disease-related mutants of RAF family kinases, which include in vitro kinase assay, RAF co-activation assay, and complementary split luciferase assay.

The rapidly accelerated fibrosarcoma (RAF) family kinases play a central role in cell biology and their dysfunction leads to cancers and developmental ...

Evaluating the Differentiation Capacity of Mouse Prostate Epithelial Cells Using Organoid Culture

The prostate epithelium is comprised predominantly of basal and luminal cells. In vivo lineage tracing has been utilized to define the differentiation capacity of mouse prostate basal and luminal cells during development, tissue-regeneration and transformation. However, evaluating cell-intrinsic and extrinsic regulators of prostate epithelial differentiation capacity using a lineage tracing approach often requires extensive breeding and can be cost-prohibitive. In the prostate organoid assay, basal and luminal cells generate prostatic epithelium ex vivo. Importantly, primary epithelial cells can be isolated from mice of any genetic background or mice treated with any number of small molecules prior to, or after, plating into three-dimensional (3D) culture. Sufficient material for evaluation of differentiation capacity is generated after 7-10 days. Collection of basal-derived and luminal-derived organoids for (1) protein analysis by Western blot and (2) immunohistochemical analysis of intact organoids by whole-mount confocal microscopy enables researchers to evaluate the ex vivo differentiation capacity of prostate epithelial cells. When used in combination, these two approaches provide complementary information about the differentiation capacity of prostate basal and luminal cells in response to genetic or pharmacological manipulation.

Mouse prostate organoids represent a promising context to evaluate mechanisms that regulate differentiation. This paper describes an improved approach to establish prostate organoids, and introduces methods to (1) collect protein lysate from organoids, and (2) fix and stain organoids for whole-mount confocal microscopy.

The prostate epithelium is comprised predominantly of basal and luminal cells. In vivo lineage tracing has been utilized to define the differentiation ...

Integration of Bioinformatics Approaches and Experimental Validations to Understand the Role of Notch Signaling in Ovarian Cancer

Notch signaling is a highly conserved regulatory pathway involved in many cellular processes. Dysregulation of this signaling pathway often leads to interference with proper development and may even result in initiation or progression of cancers in certain cases. Because this pathway serves complex and versatile functions, it can be studied extensively through many different approaches. Of these, bioinformatics provides an undeniably cost-efficient, approachable, and user-friendly method of study. Bioinformatics is a useful way to extract smaller pieces of information from large-scale datasets. Through the implementation of various bioinformatics approaches, researchers can quickly, reliably, and efficiently interpret these large datasets, yielding insightful applications and scientific discoveries. Here, a protocol is presented for integration of bioinformatics approaches to investigate the role of Notch signaling in ovarian cancer. Furthermore, bioinformatics findings are validated through experimentation.

Bioinformatics is a useful way to process large-scale datasets. Through the implementation of bioinformatics approaches, researchers can quickly, reliably, and efficiently obtain insightful applications and scientific discoveries. This article demonstrates the utilization of bioinformatics in ovarian cancer research. It also successfully validates bioinformatics findings through experimentation.

Notch signaling is a highly conserved regulatory pathway involved in many cellular processes. Dysregulation of this signaling pathway often leads to ...

Evaluating Cell Death Using Cell-Free Supernatant of Probiotics in Three-Dimensional Spheroid Cultures of Colorectal Cancer Cells

This manuscript describes a protocol to evaluate cancer cell deaths in three dimensional (3D) spheroids of multicellular types of cancer cells using supernatants from Lactobacillus fermentum cell culture, considered as probiotics cultures. The use of 3D cultures to test Lactobacillus cell-free supernatant (LCFS) are a better option than testing in 2D monolayers, especially as L. fermentum can produce anti-cancer effects within the gut. L. fermentum supernatant was identified to possess increased anti-proliferative effects against several colorectal cancer (CRC) cells in 3D culture conditions. Interestingly, these effects were strongly related to the culture model, demonstrating the notable ability of L. fermentum to induce cancer cell death. Stable spheroids were generated from diverse CRCs (colorectal cancer cells) using the protocol presented below. This protocol of generating 3D spheroid is time saving and cost effective. This system was developed to easily investigate the anti-cancer effects of LCFS in multiple types of CRC spheroids. As expected, CRC spheroids treated with LCFS strongly induced cell death during the experiment and expressed specific apoptosis molecular markers as analyzed by qRT-PCR, western blotting, and FACS analysis. Therefore, this method is valuable for exploring cell viability and evaluating the efficacy of anti-cancer drugs.

Here methods are presented to understand anti-cancer effects of Lactobacillus cell-free supernatant (LCFS). Colorectal cancer cell lines show cell deaths when treated with LCFS in 3D cultures. The process of generating spheroids can be optimized depending on the scaffold and the analysis methods presented are useful for evaluating the involved signaling pathways.

This manuscript describes a protocol to evaluate cancer cell deaths in three dimensional (3D) spheroids of multicellular types of cancer cells using ...