This research was supported by T32(CA 9686-18) and TL1 (TL1TR001431) postdoctoral training grant awards (LT), DOD PC140268 (CA), W81XWH-13-1-0327 (CA) TR000102-04 (CA) as well as U01 PAR-12-095 (Kumar) and P30 CA051008-21 (Weiner). Sample fixation, sectioning and staining was performed in the Lombardi Comprehensive Cancer Center Histology and Tissue Shared Resource. We thank Richard Schlegel for helpful discussions. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health.

1. Establishment of the 3D Cell Culture Insert System
<ol>
	<li>Place 2 polycarbonate cell culture inserts in an inverted orientation (filter side up) down in a 6 well plate (Figure 1A).</li>
	<li>Apply a thin layer of 0.1% gelatin in water to the bottom side of the insert and allow to dry (10-20 min) in a biological safety cabinet to maintain sterility.</li>
	<li>Repeat step 1.2 two more times for a total of 3 applications of 0.1% gelatin on the inserts. 
	NOTE: The gelatin coating will help limit diffusion between the chambers.</li>
	<li>To collect the primary CRCs from standard culture conditions, add 5 mL of PBS to wash the culture flask.
	<ol>
		<li>Trypsinize the cells using (1 mL for a T-25 and 2 mL for a T-75) 0.25% trypsin-EDTA for 5 min at 37 &#176;C. Gently tap the side of the flask to aid in dislodging the cells. Then proceed to stop the trypsin reaction and collect the cells by adding 5 mL of complete DMEM.</li>
		<li>Collect the cells in a 15 mL tube. Centrifuge the tube at 4 &#176;C and 188 x g and count using an automated cell counter or a hemocytometer.</li>
		<li>Re-suspend 600,000 CRCs in 250 &#956;L conditioned media (CM) and add to the properly oriented (filter side down) culture insert (Figure 1B). This is referred to as the inner chamber. 
		Note: CM is F-media conditioned by irradiated J2 cells and contains 10 &#956;m Y-27632 as previously described7,8,9,11.</li>
	</ol>
	</li>
	<li>Apply 2 mL of CM to the outer chamber of the 6 well plate and incubate at 37 &#176;C overnight (for at least 18 h).</li>
	<li>Carefully remove the CM on the inner chamber with a 1 mL or 200 &#956;L pipette and slowly add differentiation media (DM) to the inner chamber with a 1 mL pipette until full. Be careful to not disturb the cell layer.</li>
</ol>
2. Maintenance of 3D Cultures
<ol>
	<li>Check the cultures every day. Healthy cells appear as shown in Figure 2.</li>
	<li>Change the CM in the outer chamber every day or every other day depending on the metabolism of the cells.</li>
	<li>When the media of the inner chamber changes color (yellow), carefully remove the media on the inner filter chamber with a 1 mL or 200 &#956;L pipette.</li>
	<li>Aspirate the media in the outer 6 well plate chamber with an aspirating tip.</li>
	<li>Using a 1 mL pipette, slowly apply fresh DM to the inner chamber until full. Be careful not to scrape or otherwise dislodge the cell layer.</li>
	<li>Replace the media in the outer chamber with 2 mL of fresh CM.</li>
	<li>Maintain the cultures for 2 weeks, and then proceed to processing for the desired bimolecular isolation. 
	NOTE: Each row in the 6 well plate, a total of six inserts (Figure 1B), should be processed per experiment to acquire enough cells for DNA, RNA or protein for analysis.</li>
	<li>Aspirate media in the outer chamber and rinse with 2 mL phosphate buffered saline (PBS).</li>
	<li>Carefully remove media from the inner chamber with a 1 mL or 200 &#956;L pipette and add 500 &#956;L PBS. Avoid scraping or otherwise disturbing the cells on the membrane.</li>
	<li>Aspirate PBS from the outer chamber and carefully remove PBS from the inner chamber with a 1 mL or 200 &#956;L pipette. Once the PBS has been removed, proceed directly to the appropriate application detailed below. Do not allow the membrane to dry out. The culture can be kept briefly in the PBS until the application is ready to begin.</li>
</ol>
3. Processing the Filters for Pellet Banking
<ol>
	<li>Add 100 &#956;L&#160; 0.25% trypsin-EDTA to each inner chamber and incubate for 5 min at 37 &#176;C.</li>
	<li>Briefly and carefully agitate/scrape the cells on the membrane surface with a 200 &#956;L pipette while pipetting up and down (avoid puncturing the membrane). Incubate for 1 min at 37 &#176;C.</li>
	<li>Add 250 &#956;L of CM to the first inner chamber and pipette up and down gently to rinse the filter.</li>
	<li>Transfer resuspended cells to the adjacent filter chamber that contains the same media conditions and repeat pipetting up and down.</li>
	<li>Repeat this procedure for each of the inserts of a single condition. Collect and transfer cells to a 1.5 mL centrifuge tube.</li>
	<li>Rinse each inner chamber with an additional 100-200 &#956;L of CM to collect any remaining cells. Add to the 1.5 mL centrifuge tube in step 3.5.</li>
	<li>Spin the cells at 423 x g in a microcentrifuge at 4 &#176;C for 5 min.</li>
	<li>Aspirate the supernatant and wash the cell pellet once with 1000 &#956;L PBS.</li>
	<li>Spin again at 423 x g in a microcentrifuge at 4 &#176;C for 5 min.</li>
	<li>Aspirate PBS and freeze at -80 &#176;C for later use.</li>
</ol>
4. Processing the Filters for RNA or DNA Isolation
<ol>
	<li>Add 200 &#956;L of guanidinium thiocyanate-phenol-chloroform or similar extraction reagent to the inner chamber and briefly agitate the cells on the membrane surface by pipetting up and down.</li>
	<li>Incubate in the extraction reagent for 5 min at room temperature with the outer chamber dry.
	<ol>
		<li>As the filter may dissociate from the insert, wash the disassociated filter membrane by pipetting the extraction solution up and down. Collect as much of the extraction reagent as possible by tilting the 6 well plate and aspirating any residual liquid.</li>
	</ol>
	</li>
	<li>Follow the manufacturer&#39;s protocol for purification and recovery of DNA, RNA or protein.</li>
</ol>
5. Processing the Filters for Protein Isolation
<ol>
	<li>Place the filter insert in the 6 well plate on ice. To the inner chamber, add 10 &#956;L of protein lysis buffer supplemented with 1 mM sodium fluoride (NaF), 1 mM sodium vanadate (NaV), 100 mM dithiothreitol (DTT) and 100 &#956;L of anti-protease cocktail.</li>
	<li>Agitate/scrape the cells on the membrane surface with a 20 &#956;L pipette while pipetting up and down. Avoid generating bubbles in the lysis buffer.</li>
	<li>Incubate the 6 well plate with filter inserts on ice for 10 min.</li>
	<li>Repeat scraping and then rinse the membrane surface with the lysis buffer.</li>
	<li>Collect the lysates from the 6 inserts and transfer to a 1.5 mL centrifuge tube on ice.</li>
	<li>Rinse the first membrane with an additional 10 &#956;L of lysis buffer and transfer to the next filter.</li>
	<li>Repeat step 5.6 for all inserts, collecting any residual lysis buffer solution and add to the 1.5 mL tube (step 5.5).</li>
	<li>Incubate the sample on ice for an additional 5 min.</li>
	<li>Spin at maximum speed (16,873 x g in a table top centrifuge) for 15 min at 4 &#176;C.</li>
	<li>Pipette lysate supernatant into a fresh 1.5 mL tube.</li>
	<li>Proceed to the analysis of protein concentration or store lysates at -80 &#176;C.</li>
</ol>
6. Processing for H&#38;E and Immuno-staining
<ol>
	<li>Add 500 &#181;L and 1 mL of 10% NBF (neutral buffered formalin) to the inner and outer chamber and let incubate overnight at 4 &#176;C.</li>
	<li>Aspirate the NBF from the outer chamber and add 1 mL hydroxyethyl agarose (HEA) processing gel to a 1.5 mL centrifuge. Slowly melt the agarose in a microwave using low power and repeated 10-20 s pulses until the agarose is melted.</li>
	<li>Keep the HEA in a 37 &#176;C warm bath to prevent solidification until ready to use.</li>
	<li>Remove the NBF from the inner chamber and apply 25 &#956;L of molten HEA to the inner chamber and allow the agarose to solidify for 2-5 min.</li>
	<li>Wet 2 foam histology pads in 10% NBF and place one pad in an embedding cassette (see Figure 3D).</li>
	<li>Use a #11 blade scalpel (which has a very sharp, fine-pointed blade) to score the filter from the bottom side of the insert chamber, partially releasing it from the plastic insert chamber.</li>
	<li>Place a small amount (100-200 &#956;L) of NBF in a Petri dish and immerse the partially dislodged filter in the NBF (Figure 3A).</li>
	<li>With a #10 blade scalpel, gently press against the middle of the filter, from the inside of the insert chamber, to fully dislodge the filter from the insert barrel (Figure 3B). If there is any part of the filter that is still attached to the barrel, sever it with the scalpel.</li>
	<li>Cut the HEA-coated filter in half with the #10 blade scalpel (Figure 3C).</li>
	<li>Place each half of the filter onto the foam pad in the histology cassette prepared in step 6.4 (Figure 3D).</li>
	<li>Add the second 10% NBF soaked sponge to the cassette, sandwiching the filter.</li>
	<li>Snap seal the cassette, place in NBF, and incubate overnight.</li>
	<li>Process filters into paraffin blocks for sectioning and staining as described previously12.</li>
</ol>

<ol>
	<li>Gao, D., 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=Organoid+cultures+derived+from+patients+with+advanced+prostate+cancer.">Organoid cultures derived from patients with advanced prostate cancer.</a> Cell. 159 (1), 176-187 (2014).</li><li>Chapman, S., Liu, X., Meyers, C., Schlegel, R., McBride, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+keratinocytes+are+efficiently+immortalized+by+a+Rho+kinase+inhibitor.">Human keratinocytes are efficiently immortalized by a Rho kinase inhibitor.</a> J Clin Invest. 120 (7), 2619-2626 (2010).</li><li>Liu, 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=ROCK+inhibitor+and+feeder+cells+induce+the+conditional+reprogramming+of+epithelial+cells.">ROCK inhibitor and feeder cells induce the conditional reprogramming of epithelial cells.</a> Am J Pathol. 180 (2), 599-607 (2012).</li><li>Yuan, H., 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=Use+of+reprogrammed+cells+to+identify+therapy+for+respiratory+papillomatosis.">Use of reprogrammed cells to identify therapy for respiratory papillomatosis.</a> N Engl J Med. 367 (13), 1220-1227 (2012).</li><li>Signoretti, 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=p63+is+a+prostate+basal+cell+marker+and+is+required+for+prostate+development.">p63 is a prostate basal cell marker and is required for prostate development.</a> Am J Pathol. 157 (6), 1769-1775 (2000).</li><li>Lang, S. H., Frame, F. M., Collins, A. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prostate+cancer+stem+cells.">Prostate cancer stem cells.</a> J Pathol. 217 (2), 299-306 (2009).</li><li>Ringer, 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=The+induction+of+the+p53+tumor+suppressor+protein+bridges+the+apoptotic+and+autophagic+signaling+pathways+to+regulate+cell+death+in+prostate+cancer+cells.">The induction of the p53 tumor suppressor protein bridges the apoptotic and autophagic signaling pathways to regulate cell death in prostate cancer cells.</a> Oncotarget. 5 (21), 10678-10691 (2014).</li><li>Pollock, C. 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=Strigolactone+analogues+induce+apoptosis+through+activation+of+p38+and+the+stress+response+pathway+in+cancer+cell+lines+and+in+conditionally+reprogrammed+primary+prostate+cancer+cells.">Strigolactone analogues induce apoptosis through activation of p38 and the stress response pathway in cancer cell lines and in conditionally reprogrammed primary prostate cancer cells.</a> Oncotarget. 5 (6), 1683-1698 (2014).</li><li>Crogliom, 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=Analogs+of+the+Novel+Phytohormone,+Strigolactone,+Trigger+Apoptosis+and+Synergy+with+PARP1+Inhibitors+by+Inducing+DNA+Damage+and+Inhibiting+DNA+Repair.">Analogs of the Novel Phytohormone, Strigolactone, Trigger Apoptosis and Synergy with PARP1 Inhibitors by Inducing DNA Damage and Inhibiting DNA Repair.</a> Oncotarget. , (2016).</li><li>Saeed, K., 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=Comprehensive+Drug+Testing+of+Patient-derived+Conditionally+Reprogrammed+Cells+from+Castration-resistant+Prostate+Cancer.">Comprehensive Drug Testing of Patient-derived Conditionally Reprogrammed Cells from Castration-resistant Prostate Cancer.</a> Eur Urol. , (2016).</li><li>Palechor-Ceron, N., 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=Radiation+induces+diffusible+feeder+cell+factor(s)+that+cooperate+with+ROCK+inhibitor+to+conditionally+reprogram+and+immortalize+epithelial+cells.">Radiation induces diffusible feeder cell factor(s) that cooperate with ROCK inhibitor to conditionally reprogram and immortalize epithelial cells.</a> Am J Pathol. 183 (6), 1862-1870 (2013).</li><li>Coffey, A., Johnson, M. D., Berry, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SpOT+the+Correct+Tissue+Every+Time+in+Multi-tissue+Blocks.">SpOT the Correct Tissue Every Time in Multi-tissue Blocks.</a> J Vis Exp. (99), e52868 (2015).</li><li>Hidalgo, 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=Patient-derived+xenograft+models:+an+emerging+platform+for+translational+cancer+research.">Patient-derived xenograft models: an emerging platform for translational cancer research.</a> Cancer Discov. 4 (9), 998-1013 (2014).</li><li>Drost, 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=Organoid+culture+systems+for+prostate+epithelial+and+cancer+tissue.">Organoid culture systems for prostate epithelial and cancer tissue.</a> Nat Protoc. 11 (2), 347-358 (2016).</li></ol>

The authors have nothing to disclose.

Primary cell lines are an important and rapidly developing platform for cancer research. The culture insert-based 3D culture system supports the differentiation of primary prostate CRCs within a two-week timeframe. The CRC filter method represents a new, medium throughput method for prostate research. Existing mouse PDX models are time consuming and extremely expensive, and many of the PDX samples cannot be grown in culture, limiting investigator-initiated experimentation and their usefulness. In addition, while success ...

The identification and use of cancer therapies that are personalized to individuals are a primary goal in cancer research. Recently, new approaches have been developed that allow for greater ease in the establishment of primary cell cultures, potentially providing ways of both identifying and testing personalized therapies. For example, the R-spondin-based prostate organoid approach1 allows for three-dimensional (3D) culturing of normal and metastatic prostate cancer cells in a commercial extracellular matrix (e.g., Matrigel), while the Conditionally Reprogramming of Cells (CRC) method developed at Georgetown2,3 utilizes more standard 2D culture conditions. Specifically, the combination of a Rho kinase inhibitor (Y-27632) and irradiated J2 murine fibroblast feeder cells lead to the indefinite culturing of keratinocyte CRCs2. The CRC methodology is extremely robust, with primary cell lines successfully established and maintained indefinitely from the prostate and many other normal and malignant epithelial tissues3. Importantly, our CRC technology allowed for the rapid identification of the etiological basis for recurrent respiratory papillomatosis in a patient who had failed a number of previous drug treatments. In addition, using normal and tumor-derived CRCs, the successful identification of an FDA approved drug, vorinostat, was made within two weeks of initial tissue biopsy. The patient was placed on vorinostat, resulting in the successful treatment of their disease4.
The normal prostate gland is comprised of luminal, basal and the rare neuroendocrine cells5. Luminal cells form the columnar epithelial layer of the gland and express the androgen receptor (AR), as well as other luminal markers such as cytokeratins 8 and 18 and prostate-specific antigen (PSA)6. Conversely, basal cells are localized beneath the luminal layer and express cytokeratin 5 and p63, but low levels of the AR5. We7,8,9 and others10 have successfully used prostate CRCs in preclinical mechanistic drug sensitivity investigations. However, when grown under standard 2D tissue culture conditions, these cells fail to fully engage AR signaling10. Importantly, when placed under the renal capsule of immunodeficient mice, the CRCs regained normal prostate glandular architecture and function indicating that prostate CRCs retain their lineage commitment when placed in a permissive environment. The development of the filter insert-based cell culture system described here allows for the rapid (2 weeks) in vitro differentiation of prostate CRCs as evidenced by the increased expression of the AR and AR target genes as well as decreased levels of p63.
The filter inserts used contain polycarbonate membranes (pore size, 0.4 &#181;m) that can support the culturing of mammalian cells. The system, as developed, makes use of normal and malignant prostate CRCs, 6 well culture dishes and the filter inserts. Cell culture media conditioned by J2 cells11 is placed in the bottom chamber and prostate differentiating media in the top chamber. The techniques described herein support prostate luminal cell differentiation within a 2 week timeframe, consistent with the goals of personalized medicine. It was also imperative to develop the methodologies that allow for the comprehensive molecular, genetic and cellular profiling of the cultures. Approaches for isolating DNA, RNA and protein from cells released from the filter surface have been developed and streamlined for accurate repeat sample processing. Finally, the methodology required for removing the filter to enable embedding, sectioning and for H&#38;E, immunohistochemical and immunofluorescent staining, is fully described.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Corning Costar Snapwell Culture Inserts</td>
			<td>Corning</td>
			<td>3801</td>
		</tr>
		<tr>
			<td>Millicell Cell Culture Inserts</td>
			<td>Millipore</td>
			<td>PIHP01250</td>
		</tr>
		<tr>
			<td>Multiwell 6 Well</td>
			<td>Falcon</td>
			<td>353046</td>
		</tr>
		<tr>
			<td>Gelatin 0.1% in water</td>
			<td>Stemcell Technologies</td>
			<td>7903</td>
		</tr>
		<tr>
			<td>Sterile Saftey Scapel 10 Blade</td>
			<td>Integra Miltex</td>
			<td>4-510</td>
		</tr>
		<tr>
			<td>Sterile Standard Scalpel 11 Blade</td>
			<td>Integra Miltex</td>
			<td>4411</td>
		</tr>
		<tr>
			<td>RIPA Lysis and Extraction Buffer</td>
			<td>Thermofisher Scientific</td>
			<td>89900</td>
		</tr>
		<tr>
			<td>Sodium Fluoride</td>
			<td>Fishcer Scientific</td>
			<td>S299-100</td>
		</tr>
		<tr>
			<td>Sodium Vanadate</td>
			<td>Fishcer Scientific</td>
			<td>13721-39-6</td>
		</tr>
		<tr>
			<td>Dithiothreitol</td>
			<td>Sigma-Aldrich</td>
			<td>3483123</td>
		</tr>
		<tr>
			<td>Protease Inhibitor Cocktail (AEBSF, Aprotinin, Bestatin, E-64, Leupeptin and Pepstatin A)</td>
			<td>Sigma-Aldrich</td>
			<td>P8340</td>
		</tr>
		<tr>
			<td>0.25% Trypsin-EDTA (1x)</td>
			<td>Thermofisher Scientific</td>
			<td>25200-056</td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Thermofisher Scientific</td>
			<td>11965-092</td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>Sigma-Aldrich</td>
			<td>F2442</td>
		</tr>
		<tr>
			<td>Glutamine</td>
			<td>Thermofisher Scientific</td>
			<td>25030081&#160;</td>
		</tr>
		<tr>
			<td>Penicillin Streptomycin</td>
			<td>Thermofisher Scientific</td>
			<td>15140-122</td>
		</tr>
		<tr>
			<td>F-12 Nutrient Mix Media</td>
			<td>Thermofisher Scientific</td>
			<td>11765054</td>
		</tr>
		<tr>
			<td>Y-27632 dihydrochloride Rock inhibitor</td>
			<td>Enzo</td>
			<td>ALX-270-333-M025</td>
		</tr>
		<tr>
			<td>Hydrocortisone</td>
			<td>Sigma-Aldrich</td>
			<td>H0888</td>
		</tr>
		<tr>
			<td>EGF</td>
			<td>Thermofisher Scientific</td>
			<td>PHG0315</td>
		</tr>
		<tr>
			<td>Insulin</td>
			<td>Thermofisher Scientific</td>
			<td>12585-014</td>
		</tr>
		<tr>
			<td>Cholera Toxin</td>
			<td>Sigma-Aldrich</td>
			<td>C3012</td>
		</tr>
		<tr>
			<td>Gentamicin</td>
			<td>Thermofisher Scientific</td>
			<td>15710-064</td>
		</tr>
		<tr>
			<td>Fungizone</td>
			<td>Fisher Scientific</td>
			<td>BP264550</td>
		</tr>
		<tr>
			<td>Trizol Reagent</td>
			<td>Invitrogen</td>
			<td>15596026</td>
		</tr>
		<tr>
			<td>Histogel Specimen Processing Gel (hydroxyethyl agarose (HEA))</td>
			<td>Thermo Scientific</td>
			<td>HG-4000-012</td>
		</tr>
		<tr>
			<td>Non-Adherent Dressing</td>
			<td>Telfa</td>
			<td>KDL2132Z</td>
		</tr>
		<tr>
			<td>Cell Culture Dish</td>
			<td>Sigma</td>
			<td>SIAL0167</td>
		</tr>
		<tr>
			<td>HISTOSETTE II Tissue Processing / Embedding Cassettes</td>
			<td>Crystalgen</td>
			<td>CG-M492</td>
		</tr>
	</tbody>
</table>

a rapid filter insert-based 3d culture system for primary prostate cell differentiation

Conditionally reprogrammed cells (CRCs) provide a sustainable method for primary cell culture and the ability to develop extensive &#34;living biobanks&#34; of patient derived cell lines. For many types of epithelial cells, various three dimensional (3D) culture approaches have been described that support an improved differentiated state. While CRCs retain their lineage commitment to the tissue from which they are isolated, they fail to express many of the differentiation markers associated with the tissue of origin when grown under normal two dimensional (2D) culture conditions. To enhance the application of patient-derived CRCs for prostate cancer research, a 3D culture format has been defined that enables a rapid (2 weeks total) luminal cell differentiation in both normal and tumor-derived prostate epithelial cells. Herein, a filter insert-based format is described for the culturing and differentiation of both normal and malignant prostate CRCs. A detailed description of the procedures required for cell collection and processing for immunohistochemical and immunofluorescent staining are provided. Collectively the 3D culture format described, combined with the primary CRC lines, provides an important medium- to high- throughput model system for biospecimen-based prostate research.

The cell culture insert based system is a relatively simple and rapid procedure for producing 3D cultures of prostate CRCs that supports luminal cell differentiation. A schematic of the system is shown (Figure 1A) highlighting the application of the gelatin coating to the bottom surface of the filter insert. The inserts are only overturned for the application of the gelatin. In Figure 1B the filters are in the appropriate orientation for culturing. Using ...

Watch this Scientific Journal Video about A Rapid Filter Insert-based 3D Culture System for Primary Prostate Cell Differentiation at JoVE.com

A Rapid Filter Insert-based 3D Culture System for Primary Prostate Cell Differentiation

Here, we present a method for the establishment of a rapid in vitro system that supports the three dimensional culturing and subsequent luminal differentiation of primary prostate epithelial cells.

Conditionally reprogrammed cells (CRCs) provide a sustainable method for primary cell culture and the ability to develop extensive &#34;living ...

a-rapid-filter-insert-based-3d-culture-system-for-primary-prostate

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Cancer Research

8.5K Views.  Lombardi Comprehensive Cancer Center. Here, we present a method for the establishment of a rapid in vitro system that supports the three dimensional culturing and subsequent luminal differentiation of primary prostate epithelial cells.

Video: A Rapid Filter Insert-based 3D Culture System for Primary Prostate Cell Differentiation

A Protocol for Rapid Post-mortem Cell Culture of Diffuse Intrinsic Pontine Glioma (DIPG)

Diffuse Intrinsic Pontine Glioma (DIPG) is a childhood brainstem tumor that carries a universally fatal prognosis. Because surgical resection is not a viable treatment strategy and biopsy is not routinely performed, the availability of patient samples for research is limited. Consequently, efforts to study this disease have been challenged by a paucity of faithful disease models. To address this need, we describe here a protocol for the rapid processing of post-mortem autopsy tissue samples in order to generate durable patient-derived cell culture models that can be used in in vitro assays or in vivo orthotopic xenograft experiments. These models can be used to screen for potential drug targets and to study fundamental pathobiological processes within DIPG. This protocol can further be extended to analyze and isolate tumor and microenvironmental cells using Fluorescence-activated Cell Sorting (FACS), which enables subsequent analysis of gene expression, protein expression, or epigenetic modifications of DNA at the bulk cell or single cell level. Finally, this protocol can also be adapted to generate patient-derived cultures for other central nervous system tumors.

A Protocol for Rapid Post-mortem Cell Culture of Diffuse Intrinsic Pontine Glioma DIPG

This protocol describes a method for the rapid processing of post-mortem diffuse intrinsic pontine glioma samples for the establishment of patient-derived cell culture models or direct characterization of tumor and microenvironmental cells.

Diffuse Intrinsic Pontine Glioma (DIPG) is a childhood brainstem tumor that carries a universally fatal prognosis. Because surgical resection is not a ...

Establishment of a Primary Culture of Patient-derived Soft Tissue Sarcoma

Soft tissue sarcomas (STS) represent a spectrum of heterogeneous malignancies with a difficult diagnosis, classification, and management. To date, more than 50 histological subtypes of these rare solid tumors have been identified. Thus, due to their extraordinary diversity and low incidence, our understanding of the biology of these tumors is still limited. Patient-derived cultures represent the ideal platform to study STS pathophysiology and pharmacology. We thus developed a human preclinical model of STS starting from tumor specimens harvested from patients undergoing surgical resection. Patient-derived STS cell cultures were obtained from the surgical specimens by collagenase digestion and isolated by filtration. Cells were counted, seeded, and left for 14 days in standard monolayer cultures and then processed by downstream analysis. Before performing molecular or pharmaceutical analyses, the establishment of STS primary cultures was confirmed through the evaluation of cytomorphologic features and, when available, immunohistochemical markers. This method represents a useful tool 1) to study the natural history of these poorly explored malignancies and 2) to test the effects of different drugs in an effort to learn more about their mechanisms of action.

The following protocol focuses on the establishment of a primary culture of patient-derived soft tissue sarcoma (STS). This model could help us to better understand the molecular background and pharmacological profile of these rare malignancies and could represent a starting point for further research aimed at improving STS management.

Soft tissue sarcomas (STS) represent a spectrum of heterogeneous malignancies with a difficult diagnosis, classification, and management. To date, more ...

Therapy Testing in a Spheroid-based 3D Cell Culture Model for Head and Neck Squamous Cell Carcinoma

Current treatment options for advanced and recurrent head and neck squamous cell carcinoma (HNSCC) enclose radiation and chemo-radiation approaches with or without surgery. While platinum-based chemotherapy regimens currently represent the gold standard in terms of efficacy and are given in the vast majority of cases, new chemotherapy regimens, namely immunotherapy are emerging. However, the response rates and therapy resistance mechanisms for either chemo regimen are hard to predict and remain insufficiently understood. Broad variations of chemo and radiation resistance mechanisms are known to date. This study describes the development of a standardized, high-throughput in vitro assay to assess HNSCC cell line&#39;s response to various therapy regimens, and hopefully on primary cells from individual patients as a future tool for personalized tumor therapy. The assay is designed to being integrated into the quality-controlled standard algorithm for HNSCC patients at our tertiary care center; however, this will be subject of future studies. Technical feasibility looks promising for primary cells from tumor biopsies from actual patients. Specimens are then transferred into the laboratory. Biopsies are mechanically separated followed by enzymatic digestion. Cells are then cultured in ultra-low adhesion cell culture vials that promote the reproducible, standardized and spontaneous formation of three-dimensional, spheroid-shaped cell conglomerates. Spheroids are then ready to be exposed to chemo-radiation protocols and immunotherapy protocols as needed. The final cell viability and spheroid size are indicators of therapy susceptibility and therefore could be drawn into consideration in future to assess the patients&#39; likely therapy response. This model could be a valuable, cost-efficient tool towards personalized therapy for head and neck cancer.

We describe the evolution of a spheroid-based, three-dimensional in vitro model that enables us to test the current standard of experimental therapy regimens for head and neck squamous cell carcinoma on cell lines, aiming at evaluating therapy susceptibility and resistance on primary cells from human specimens in the future.

Current treatment options for advanced and recurrent head and neck squamous cell carcinoma (HNSCC) enclose radiation and chemo-radiation approaches with ...

Virus Delivery of CRISPR Guides to the Murine Prostate for Gene Alteration

With an increasing incidence of prostate cancer, identification of new tumor drivers or modulators is crucial. Genetically engineered mouse models (GEMM) for prostate cancer are hampered by tumor heterogeneity and its complex microevolution dynamics. Traditional prostate cancer mouse models include, amongst others, germline and conditional knockouts, transgenic expression of oncogenes, and xenograft models. Generation of de novo mutations in these models is complex, time-consuming, and costly. In addition, most of traditional models target the majority of the prostate epithelium, whereas human prostate cancer is well known to evolve as an isolated event in only a small subset of cells. Valuable models need to simulate not only prostate cancer initiation, but also progression to advanced disease.
Here we describe a method to target a few cells in the prostate epithelium by transducing cells by viral particles. The delivery of an engineered virus to the murine prostate allows alteration of gene expression in the prostate epithelia. Virus type and quantity will hereby define the number of targeted cells for gene alteration by transducing a few cells for cancer initiation and many cells for gene therapy. Through surgery-based injection in the anterior lobe, distal from the urinary track, the tumor in this model can expand without impairing the urinary function of the animal. Furthermore, by targeting only a subset of prostate epithelial cells the technique enables clonal expansion of the tumor, and therefore mimics human tumor initiation, progression, as well as invasion through the basal membrane.
This novel technique provides a powerful prostate cancer model with improved physiological relevance. Animal suffering is limited, and since no additional breeding is required, overall animal count is reduced. At the same time, analysis of new candidate genes and pathways is accelerated, which in turn is more cost efficient.

This protocol describes a newly established method for virus delivery to the murine prostate. Using either CRISPR/Cas9 technology, gene overexpression, or Cre recombinase delivery, the technique allows orthotopic alteration of gene expression and implements a novel mouse model for prostate cancer.

With an increasing incidence of prostate cancer, identification of new tumor drivers or modulators is crucial. Genetically engineered mouse models (GEMM) ...

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. ...

Identification, Histological Characterization, and Dissection of Mouse Prostate Lobes for In Vitro 3D Spheroid Culture Models

Genetically engineered mouse models (GEMMs) serve as effective pre-clinical models for investigating most types of human cancers, including prostate cancer (PCa). Understanding the anatomy and histology of the mouse prostate is important for the efficient use and proper characterization of such animal models. The mouse prostate has four distinct pairs of lobes, each with their own characteristics. This article demonstrates the proper method of dissection and identification of mouse prostate lobes for disease analysis. Post-dissection, the prostate cells can be further cultured in vitro for mechanistic understanding. Since mouse prostate primary cells tend to lose their normal characteristics when cultured in vitro, we outline here a method for isolating the cells and growing them as 3D spheroid cultures, which is effective for preserving the physiological characteristics of the cells. These 3D cultures can be used for analyzing cell morphology and behavior in near-physiological conditions, investigating altered levels and localizations of key proteins and pathways involved in the development and progression of a disease, and looking at responses to drug treatments.

Genetically engineered mice are useful models for investigating prostate cancer mechanisms. Here we present a protocol to identify and dissect prostate lobes from a mouse urogenital system, differentiate them based on histology, and isolate and culture the primary prostate cells in vitro as spheroids for downstream analyses.

Genetically engineered mouse models (GEMMs) serve as effective pre-clinical models for investigating most types of human cancers, including prostate ...

A Three-dimensional Thymic Culture System to Generate Murine Induced Pluripotent Stem Cell-derived Tumor Antigen-specific Thymic Emigrants

The inheritance of pre-rearranged T cell receptors (TCRs) and their epigenetic rejuvenation make induced pluripotent stem cell (iPSC)-derived T cells a promising source for adoptive T cell therapy (ACT). However, classical in vitro methods for producing regenerated T cells from iPSC result in either innate-like or terminally differentiated T cells, which are phenotypically and functionally distinct from na&#239;ve T cells. Recently, a novel three-dimensional (3D) thymic culture system was developed to generate a homogenous subset of CD8&#945;&#946;+ antigen-specific T cells with a na&#239;ve T cell-like functional phenotype, including the capacity for proliferation, memory formation, and tumor suppression in vivo. This protocol avoids aberrant developmental fates, allowing for the generation of clinically relevant iPSC-derived T cells, designated as iPSC-derived thymic emigrants (iTE), while also providing a potent tool to elucidate the subsequent functions necessary for T cell maturation after thymic selection.

This article describes a novel method to generate tumor antigen-specific induced pluripotent stem cell-derived thymic emigrants (iTE) by a three-dimensional (3D) thymic culture system. iTE are a homogenous subset of T cells closely related to na&#239;ve T cells with the capacity for proliferation, memory formation, and tumor suppression.

The inheritance of pre-rearranged T cell receptors (TCRs) and their epigenetic rejuvenation make induced pluripotent stem cell (iPSC)-derived T cells a ...

Rapid Generation of Primary Murine Melanocyte and Fibroblast Cultures

Defects in fibroblast or melanocyte function are associated with skin diseases, including poor barrier function, defective wound healing, pigmentation defects and cancer. Vital to the understanding and amelioration of these diseases are experiments in primary fibroblast and melanocyte cultures. Nevertheless, current protocols for melanocyte isolation require that the epidermal and dermal layers of the skin are trypsinized and manually disassociated. This process is time consuming, technically challenging and contributes to inconsistent yields. Furthermore, methods to simultaneously generate pure fibroblast cultures from the same tissue sample are not readily available. Here, we describe an improved protocol for isolating melanocytes and fibroblasts from the skin of mice on postnatal days 0-4. In this protocol, whole skin is mechanically homogenized using a tissue chopper and then briefly digested with collagenase and trypsin. Cell populations are then isolated through selective plating followed by G418 treatment. This procedure results in consistent melanocyte and fibroblast yields from a single mouse in less than 90 min. This protocol is also easily scalable, allowing researchers to process large cohorts of animals without a significant increase in hands-on time. We show through flow cytometric assessments that cultures established using this protocol are highly enriched for melanocytes or fibroblasts.

This protocol outlines a rapid method to simultaneously generate melanocyte and fibroblast cultures from the skin of 0-4 day old mice. These primary cultures can be maintained and manipulated in vitro to study a variety of physiologically relevant processes, including skin cell biology, pigmentation, wound healing and melanoma.

Defects in fibroblast or melanocyte function are associated with skin diseases, including poor barrier function, defective wound healing, pigmentation ...

A 3D Spheroid Model as a More Physiological System for Cancer-Associated Fibroblasts Differentiation and Invasion In Vitro Studies

Defining the ideal model for an in vitro study is essential, mainly if studying physiological processes such as differentiation of cells. In the tumor stroma, host fibroblasts are stimulated by cancer cells to differentiate. Thus, they acquire a phenotype that contributes to the tumor microenvironment and supports tumor progression. By using the spheroid model, we have set up such a 3D in vitro model system, in which we analyzed the role of laminin-332 and its receptor integrin &#945;3&#946;1 in this differentiation process. This spheroid model system not only reproduces the tumor microenvironment conditions in a more accurate way, but also is a very versatile model since it allows different downstream studies, such as immunofluorescent staining of both intra- and extracellular markers, as well as deposited extracellular matrix proteins. Moreover, transcriptional analyses by qPCR, flow cytometry and cellular invasion can be studied with this model. Here, we describe a protocol of a spheroid model to assess the role of CAFs&#39; integrin &#945;3&#946;1 and its ectopically deposited ligand, laminin-332, in differentiation and in supporting the invasion of pancreatic cancer cells.

The goal of this protocol is to establish a 3D in vitro model to study the differentiation of cancer-associated fibroblasts (CAFs) in a tumor bulk-like environment, which can be addressed in different analysis systems, such as immunofluorescence, transcriptional analysis and life cell imaging.

Defining the ideal model for an in vitro study is essential, mainly if studying physiological processes such as differentiation of cells. In the tumor ...

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 ...