All animal studies were approved by the University of Maryland and the Johns Hopkins University Institutional Animal Care and Use Committee. C57BL/6 female mice, 6-8 weeks of age, were used for the present study. The mice were obtained from commercial sources (see Table of Materials). All Biosafety Level 2 (BSL-2) regulations were followed, including the usage of masks, gloves, and gowns.
1. Initial intracranial tumor implantation
<ol>
	<li>At the initial ph...

<ol>
	<li>Mineo, J. F., 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=Prognosis+factors+of+survival+time+in+patients+with+glioblastoma+multiforme:+a+multivariate+analysis+of+340+patients.">Prognosis factors of survival time in patients with glioblastoma multiforme: a multivariate analysis of 340 patients.</a> Acta Neurochirurgica. 149 (3), 245-252 (2007).</li><li>Miyai, 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=Current+trends+in+mouse+models+of+glioblastoma.">Current trends in mouse models of glioblastoma.</a> Journal of Neuro-Oncology. 135 (3), 423-432 (2017).</li><li>Raj, D., Agrawal, P., Gaitsch, H., Wicks, E., Tyler, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacological+strategies+for+improving+the+prognosis+of+glioblastoma.">Pharmacological strategies for improving the prognosis of glioblastoma.</a> Expert Opinion on Pharmacotherapy. 22 (15), 2019-2031 (2021).</li><li>Alomari, 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=Drug+repurposing+for+Glioblastoma+and+current+advances+in+drug+delivery-a+comprehensive+review+of+the+literature.">Drug repurposing for Glioblastoma and current advances in drug delivery-a comprehensive review of the literature.</a> Biomolecules. 11 (12), 1870 (2021).</li><li>Serra, 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=Combined+intracranial+Acriflavine,+temozolomide+and+radiation+extends+survival+in+a+rat+glioma+model.">Combined intracranial Acriflavine, temozolomide and radiation extends survival in a rat glioma model.</a> European Journal of Pharmaceutics and Biopharmaceutics : Official Journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik eV. 170, 179-186 (2022).</li><li>Tang, B., Foss, K., Lichtor, T., Phillips, H., Roy, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Resection+of+orthotopic+murine+brain+glioma.">Resection of orthotopic murine brain glioma.</a> Neuroimmunology and Neuroinflammation. 8 (1), 64-69 (2021).</li><li>Ozawa, T., James, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Establishing+intracranial+brain+tumor+xenografts+with+subsequent+analysis+of+tumor+growth+and+response+to+therapy+using+bioluminescence+imaging.">Establishing intracranial brain tumor xenografts with subsequent analysis of tumor growth and response to therapy using bioluminescence imaging.</a> Journal of Visualized Experiments. (41), e1986 (2010).</li><li>Poussard, 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=In+vivo+imaging+systems+(IVIS)+detection+of+a+neuro-invasive+encephalitic+virus.">In vivo imaging systems (IVIS) detection of a neuro-invasive encephalitic virus.</a> Journal of Visualized Experiments. (70), e4429 (2012).</li><li>Lachin, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonparametric+statistical+analysis.">Nonparametric statistical analysis.</a> JAMA. 323 (20), 2080-2081 (2020).</li><li>Louis, K. S., Siegel, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+viability+analysis+using+trypan+blue:+manual+and+automated+methods.">Cell viability analysis using trypan blue: manual and automated methods.</a> Methods in Molecular Biology. 740, 7-12 (2011).</li><li>Spina, R., Voss, D. M., Asnaghi, L., Sloan, A., Bar, E. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+cytometry-based+drug+screening+system+for+the+identification+of+small+molecules+that+promote+cellular+differentiation+of+Glioblastoma+stem+cells.">Flow cytometry-based drug screening system for the identification of small molecules that promote cellular differentiation of Glioblastoma stem cells.</a> Journal of Visualized Experiments. (131), e56176 (2018).</li><li>Rodgers, 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=Virtual+histology+of+an+entire+mouse+brain+from+formalin+fixation+to+paraffin+embedding.+Part+2:+Volumetric+strain+fields+and+local+contrast+changes.">Virtual histology of an entire mouse brain from formalin fixation to paraffin embedding. Part 2: Volumetric strain fields and local contrast changes.</a> Journal of Neuroscience Methods. 365, 109385 (2022).</li><li>Connolly, N. 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=Elevated+fibroblast+growth+factor-inducible+14+expression+transforms+proneural-like+gliomas+into+more+aggressive+and+lethal+brain+cancer.">Elevated fibroblast growth factor-inducible 14 expression transforms proneural-like gliomas into more aggressive and lethal brain cancer.</a> GLIA. 69 (9), 2199-2214 (2021).</li><li>Stall, 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=Comparison+of+T2+and+FLAIR+imaging+for+target+delineation+in+high+grade+gliomas.">Comparison of T2 and FLAIR imaging for target delineation in high grade gliomas.</a> Radiation Oncology. 5, 5 (2010).</li><li>Das, 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=Establishing+a+standardized+method+for+the+effective+intraoperative+collection+and+biological+preservation+of+brain+tumor+tissue+samples+using+a+novel+tissue+preservation+system:+a+pilot+study.">Establishing a standardized method for the effective intraoperative collection and biological preservation of brain tumor tissue samples using a novel tissue preservation system: a pilot study.</a> World Neurosurgery. , (2022).</li><li>Zusman, E., 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=Tissues+harvested+using+an+automated+surgical+approach+confirm+molecular+heterogeneity+of+Glioblastoma+and+enhance+specimen's+translational+research+value.">Tissues harvested using an automated surgical approach confirm molecular heterogeneity of Glioblastoma and enhance specimen's translational research value.</a> Frontiers in Oncology. 9, (2019).</li><li>McLaughlin, 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=Side-cutting+aspiration+device+for+endoscopic+and+microscopic+tumor+removal.">Side-cutting aspiration device for endoscopic and microscopic tumor removal.</a> Journal of Neurological Surgery Part B. 73 (1), 11-20 (2012).</li></ol>

Tumor resection is a cornerstone of neurosurgical oncology treatment plans for both low-grade and high-grade brain tumors. Cytoreduction and debulking of the tumor correlate with improved neurological function and overall survival in patients with brain tumors1,2,5,6. Although protocols for surgical resection have been previously described in rodent models, these protocols have suffered from se...

Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults. Despite recent advances in neurosurgery, targeted drug development, and radiation therapy, the 5-year survival rate for GBM patients is less than 5%, a statistic that has not significantly improved in over three decades1. Hence, there is a need for more effective treatment strategies.
To develop new therapies, it is becoming increasingly apparent that investigational protocols need to (1) utilize translatable preclinical models that accurately recapitulate the tumor heterogeneity and microenvironment, (2) mirror the standard therapeutic regimen used in patients with GBM, which currently includes surgery, radiotherapy, and chemotherapy, and (3) account for the difference between resected core and residual, invasive tumor tissues2,3,4,5.&#160;However, most of the currently available preclinical brain tumor models either do not implement surgical resection or utilize surgical resection models that are relatively time-consuming, leading to a significant amount of blood loss or lack standardization. Furthermore, performing resection of rodent brain tumors can be challenging due to a lack of clinically comparable surgical tools or protocols and the absence of an established platform6 for systematic tissue collection (Table 1).
The present protocol aims to describe a standardized paradigm for rodent brain tumor resection and tissue preservation using a multi-functional non-ablative minimally invasive resection system (MIRS) and an integrated tissue preservation system (TPS) (Figure 1). It is expected that this unique technique will provide a standardized platform that can be utilized in various studies in preclinical research for GBM and other types of brain tumor models. Researchers investigating therapeutic or diagnostic modalities for brain tumors can implement this protocol to achieve a standardized resection in their studies.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1 mL syringes</td>
			<td>BD</td>
			<td>309628</td>
			<td></td>
		</tr>
		<tr>
			<td>15 mL conical tubes</td>
			<td>Corning</td>
			<td>430052</td>
			<td></td>
		</tr>
		<tr>
			<td>200 proof ethanol</td>
			<td>PharmCo</td>
			<td>111000200</td>
			<td></td>
		</tr>
		<tr>
			<td>5 mL pipettes</td>
			<td>CoStar</td>
			<td>4487</td>
			<td></td>
		</tr>
		<tr>
			<td>70 micron filter</td>
			<td>Fisher</td>
			<td>08-771-2</td>
			<td></td>
		</tr>
		<tr>
			<td>Accutase</td>
			<td>Millipore Sigma</td>
			<td>SIG-SCR005</td>
			<td></td>
		</tr>
		<tr>
			<td>Anased (Xylazine injection, 100 mg/mL)</td>
			<td>Covetrus</td>
			<td>33198</td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthesia System</td>
			<td>Patterson Scientific</td>
			<td>78935903</td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthesic Gas Waste Container</td>
			<td>Patterson Scientific</td>
			<td>78909457</td>
			<td></td>
		</tr>
		<tr>
			<td>Bench protector underpad</td>
			<td>Covidien</td>
			<td>10328</td>
			<td></td>
		</tr>
		<tr>
			<td>C57Bl/6, 6-8 week old mice</td>
			<td>Charles River Laboratories</td>
			<td>Strain Code 027</td>
			<td></td>
		</tr>
		<tr>
			<td>ChroMini Pro</td>
			<td>Moser</td>
			<td>Type 1591-Q</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase-Dispase</td>
			<td>Roche</td>
			<td>#10269638001</td>
			<td></td>
		</tr>
		<tr>
			<td>Countess II Automated Cell Counter</td>
			<td>Thermo Fisher</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Countess II FL Hemacytometer</td>
			<td>Thermo Fisher</td>
			<td>A25750</td>
			<td></td>
		</tr>
		<tr>
			<td>Debris Removal Solution</td>
			<td>Miltenyi Biotech</td>
			<td>#130-109-398</td>
			<td></td>
		</tr>
		<tr>
			<td>D-Luciferin</td>
			<td>Goldbio</td>
			<td>LUCK-1G</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM F12 media</td>
			<td>Corning</td>
			<td>10-090-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM media</td>
			<td>Corning</td>
			<td>10-013-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>DNAse I</td>
			<td>Sigma Aldrich</td>
			<td>#10104159001</td>
			<td></td>
		</tr>
		<tr>
			<td>Eppendorf tubes</td>
			<td>Posi-Click</td>
			<td>1149K01</td>
			<td></td>
		</tr>
		<tr>
			<td>Euthanasia solution</td>
			<td>Henry Schein</td>
			<td>71073</td>
			<td></td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>Millipore Sigma</td>
			<td>F4135</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Thermo Fisher</td>
			<td>10437-028</td>
			<td></td>
		</tr>
		<tr>
			<td>Formalin</td>
			<td>Invitrogen</td>
			<td>INV-28906</td>
			<td></td>
		</tr>
		<tr>
			<td>Gauze</td>
			<td>Henry Schein</td>
			<td>101-4336</td>
			<td></td>
		</tr>
		<tr>
			<td>hEGF</td>
			<td>PeproTech EC</td>
			<td>100-15</td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin</td>
			<td>Sigma</td>
			<td>H-3149</td>
			<td></td>
		</tr>
		<tr>
			<td>hFGF-b</td>
			<td>PeproTech EC</td>
			<td>1001-18B</td>
			<td></td>
		</tr>
		<tr>
			<td>Induction Chamber</td>
			<td>Patterson Scientific</td>
			<td>78933388</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Covetrus</td>
			<td>11695-6777-2</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane Vaporizer</td>
			<td>Patterson Scientific</td>
			<td>78916954</td>
			<td></td>
		</tr>
		<tr>
			<td>Ketamine</td>
			<td>Covetrus</td>
			<td>11695-0703-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Kopf Stereotactic frame</td>
			<td>Kopf Instruments</td>
			<td>5001</td>
			<td></td>
		</tr>
		<tr>
			<td>Lightfield Microscope</td>
			<td>BioTek</td>
			<td>Cytation 5</td>
			<td></td>
		</tr>
		<tr>
			<td>Microinjection Unit</td>
			<td>Kopf</td>
			<td>5001</td>
			<td></td>
		</tr>
		<tr>
			<td>Micromotor drill</td>
			<td>Foredom</td>
			<td>F210418</td>
			<td></td>
		</tr>
		<tr>
			<td>MRI system</td>
			<td>Bruker</td>
			<td>7T Biospec Avance III MRI Scanner</td>
			<td></td>
		</tr>
		<tr>
			<td>NICO Myriad System</td>
			<td>NICO Corporation</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ophthalmic ointment</td>
			<td>Puralube vet ointment</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Papain</td>
			<td>Sigma Aldrich</td>
			<td>#P4762</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS</td>
			<td>Invitrogen</td>
			<td>#14190250</td>
			<td></td>
		</tr>
		<tr>
			<td>PenStrep</td>
			<td>Millipore Sigma</td>
			<td>N1638</td>
			<td></td>
		</tr>
		<tr>
			<td>Percoll solution</td>
			<td>Sigma Aldrich</td>
			<td>&#160;#P4937</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipette controller</td>
			<td>Falcon</td>
			<td>A07260</td>
			<td></td>
		</tr>
		<tr>
			<td>Povidone-iodine solution</td>
			<td>Aplicare</td>
			<td>52380-1905-08</td>
			<td></td>
		</tr>
		<tr>
			<td>Progesterone</td>
			<td>Sigma</td>
			<td>P-8783</td>
			<td></td>
		</tr>
		<tr>
			<td>Putrescine</td>
			<td>Sigma</td>
			<td>P-5780</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI Media</td>
			<td>Invitrogen</td>
			<td>INV-72400120</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel blade</td>
			<td>Covetrus</td>
			<td>7319</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel handle</td>
			<td>Fine Science Tools</td>
			<td>91003-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Skin marker</td>
			<td>Time Out</td>
			<td>D538,851</td>
			<td></td>
		</tr>
		<tr>
			<td>Staple remover</td>
			<td>MikRon</td>
			<td>ACR9MM</td>
			<td></td>
		</tr>
		<tr>
			<td>Stapler</td>
			<td>MikRon</td>
			<td>ACA9MM</td>
			<td></td>
		</tr>
		<tr>
			<td>Staples</td>
			<td>Clay Adams</td>
			<td>427631</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereotactic Frame</td>
			<td>Kopf Instruments</td>
			<td>5000</td>
			<td></td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Sigma Aldrich</td>
			<td>S9378</td>
			<td></td>
		</tr>
		<tr>
			<td>Suture, vicryl 4-0</td>
			<td>Ethicon</td>
			<td>J494H</td>
			<td></td>
		</tr>
		<tr>
			<td>T-75 culture flask</td>
			<td>Sarstedt</td>
			<td>83-3911-002</td>
			<td></td>
		</tr>
		<tr>
			<td>TheraPEAKTM ACK Lysing Buffer (1x)</td>
			<td>Lonza</td>
			<td>BP10-548E</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin-EDTA</td>
			<td>Corning</td>
			<td>MDT-25-053-CI</td>
			<td></td>
		</tr>
	</tbody>
</table>

implementation of minimally invasive brain tumor resection in rodents for high viability tissue collection

The present protocol describes a standardized paradigm for rodent brain tumor resection and tissue preservation. In clinical practice, maximal tumor resection is the standard-of-care treatment for most brain tumors. However, most currently available preclinical brain tumor models either do not include resection, or utilize surgical resection models that are time-consuming and lead to significant postoperative morbidity, mortality, or experimental variability. In addition, performing resection in rodents can be daunting for several reasons, including a lack of clinically comparable surgical tools or protocols and the absence of an established platform for standardized tissue collection. This protocol highlights the use of a multi-functional, non-ablative resection device and an integrated tissue preservation system adapted from the clinical version of the device. The device applied in the present study combines tunable suction and a cylindrical blade at the aperture to precisely probe, cut, and suction tissue. The minimally invasive resection device performs its functions via the same burr hole used for the initial tumor implantation. This approach minimizes alterations to regional anatomy during biopsy or resection surgeries and reduces the risk of significant blood loss. These factors significantly reduced the operative time (&#60;2 min/animal), improved postoperative animal survival, lower variability in experimental groups, and result in high viability of resected tissues and cells for future analyses. This process is facilitated by a blade speed of ~1,400 cycles/min, which allows the harvesting of tissues into a sterile closed system that can be filled with a physiologic solution of choice. Given the emerging importance of studying and accurately modeling the impact of surgery, preservation and rigorous comparative analysis of regionalized tumor resection specimens, and intra-cavity-delivered therapeutics, this unique protocol will expand opportunities to explore unanswered questions about perioperative management and therapeutic discovery for brain tumor patients.

Surgical resection using the MIRS results in a significant decrease in the tumor burden 
In the group with a smaller tumor burden, the mean baseline bioluminescent signal was 5.5e+006 photons/s &#177; 0.2e+006 in the subgroup that underwent resection. Following resection, the mean bioluminescent signal decreased to 3.09e+006 photons/s &#177; 0.3e+006, (p &#60;0.0001, Mann-Whitney test)9&#160;(Figure 2). The bioluminescen...

Watch this Scientific Journal Video about Implementation of Minimally Invasive Brain Tumor Resection in Rodents for High Viability Tissue Collection at JoVE.com

Implementation of Minimally Invasive Brain Tumor Resection in Rodents for High Viability Tissue Collection

The present protocol describes a standardized resection of brain tumors in rodents through a minimally invasive approach with an integrated tissue preservation system. This technique has implications for accurately mirroring the standard of care in rodent and other animal models.

The present protocol describes a standardized paradigm for rodent brain tumor resection and tissue preservation. In clinical practice, maximal tumor ...

This is a brain tumor resection paradigm that is highly needed in preclinical research on therapeutics for brain tumors. It allows a standardized resection through a minimally-invasive approach, while at the same time, it's also coupled to an automated tissue preservation system. This protocol allows animal to survive after surgery and thus, aids in understanding the changes in disease state after therapy in the same animal.This helps in sequential and time-lapse therapeutic applications. Using this technique, we can evaluate the biology of the disease and plan for possible subsequent management. This has significant implications and opportunities in drug discovery and novel therapeutics.The concepts of standardized resection, a minimally-invasive approach, and automated tissue preservation can be extended to other types of tumors in different organ systems, such as liver tumors and head and neck cancers. The protocol is simple and the system is user-friendly. It is best to read the published protocol, which contains all the necessary steps and troubleshooting.Begin the experiment by assessing the mouse for sedation by pinching the toe. Apply ophthalmic ointment to the eyes to avoid dryness of the cornea. Then, place the mouse on a stereotactic frame.Remove the staple from the previous surgery and disinfect the skin with alternating cycles of a chlorhexidine-or betaine-based scrub and alcohol. Then create a one-centimeter longitudinal midline incision along the previous surgical scar using a sterile scalpel. Attach the MIRS hand piece to the stereotactic arm through the stage adapter.To set up the MIRS machine, insert the power cord set on the rear panel into the power cord receptacle. Turn the power to the system on or off by toggling between zero and one. Insert one end of the nitrogen hose into the male fitting on the rear panel of the console.Rotate the connection nut clockwise to tighten it. Ensure that the supply pressure does not exceed 100 PSIG and attach the hose to the nitrogen supply. Seal the lid of the vacuum port to avoid any leakage.Check that the aspiration knob on the front of the console is set at 100, that there is no leakage in the aspiration system, and that the nitrogen input supply pressure is correct. Insert the gray foot pedal connector into its gray receptacle until it clicks. In the same way, insert the blue handpiece connector into its blue receptacle.Prime each handpiece by aspirating sterile fluid into the aperture through the tubing and handpiece and then into the canister to ensure that the inside of the tubing and handpiece are lubricated. Select the mode for aspiration on the console front panel and initiate using the foot pedal. Insert the 23-G MIRS cannula into the burr hole to a depth of 2.5 millimeters.Initiate the resection process by pressing the foot pedal connected to the cannula. Perform full cycles of resection using the control knob in the handpiece. After the resection process, withdraw the 23-gauge MIRS cannula and add five milliliters of 1X PBS to flush the tubing and dislodge any residual debris.Then, close the wound with a stapler and remove the mouse from the stereotactic frame. Return the mouse to the heating pad to recover from anesthesia before placing it back into its cage. After the experiment, purge the cannula with chilled media and air to push all of the resected tissue back to the collection canister.Remove the collection canister from the system and place a cap. Next, place the distal tip of the cannula into 3%hydrogen peroxide and apply suction to fill the suction line back to the suction collection canister. Let it stand for 60 to 90 seconds and intermittently pulse air and media to flush it.Immerse the tumor sample in a tissue culture dish containing RBC lysis medium for five minutes at room temperature. Then place a 70-micron filter on a 50-milliliter conical tube and use a syringe plunger to pass the tumor sample through the filter. With a transfer pipette, use the RPMI 1640 media to pass the cells and any tissue mass through the filter.Centrifuge at 428 times G for five minutes at four degrees Celsius. Discard the supernatant and resuspend each sample in five milliliters of prepared RPMI 1640 medium. Place the samples in a shaker incubator for 20 minutes at 200 RPM at 37 degrees Celsius.After incubation, centrifuge the samples at 428 times G for five minutes at four degrees Celsius and discard the supernatant. Filter single cells through a 70-micron cell strainer and centrifuge at 274 times G for three minutes at four degrees Celsius. Conduct cell viability analysis with trypan blue and a hemocytometer.Surgical resection in mice using MIRS caused a significant decrease in the tumor burden as indicated by the reduction in the mean baseline bioluminescent signal for groups with both large and small tumor burden. Compared to the pre-resection MRI images of tumors, the resection cavity can be identified on the post-resection scans as a large, round hypointense area at the tumor inoculation site. In H&E stained sections, a clear circular resection cavity with a rim of blood products, inflammation, and residual tumor cells were observed.The resection volume significantly increased when two rotations of the cutting aperture were performed, which allowed optimization of resection volume as per tumor burden. Comparison of survival in mice with untreated tumors versus mice undergoing resection of tumors by MIRS showed an increase in survival from 16 to 22 days in the small tumor group. Similarly, in the group with a larger tumor burden, the median survival increased from 12 to 19 days.Light microscopy images of the samples taken from the tissue preservation system appeared as single cells with the presence of a few small chunks of tissue on day zero. After seven days, the cells harvested with MIRS showed neurosphere formation in suspension cultures, which indicated their tumor initiation potential. It's important to purge and flush the tubing system right after the procedure to avoid a clogging the system.Following this procedure, efficacy studies of therapeutics and studies on diagnostic and prognostic markers can be used on surviving animals after surgical resection with the minimally-invasive resection system.

implementation-minimally-invasive-brain-tumor-resection-rodents-for

Research

JoVE Journal

Cancer Research

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 ...

Generation of High-Throughput Three-Dimensional Tumor Spheroids for Drug Screening

Cancer cells have routinely been cultured in two dimensions (2D) on a plastic surface. This technique, however, lacks the true environment a tumor mass is exposed to in vivo. Solid tumors grow not as a sheet attached to plastic, but instead as a collection of clonal cells in a three-dimensional (3D) space interacting with their neighbors, and with distinct spatial properties such as the disruption of normal cellular polarity. These interactions cause 3D-cultured cells to acquire morphological and cellular characteristics which are more relevant to in vivo tumors. Additionally, a tumor mass is in direct contact with other cell types such as stromal and immune cells, as well as the extracellular matrix from all other cell types. The matrix deposited is comprised of macromolecules such as collagen and fibronectin.
In an attempt to increase the translation of research findings in oncology from bench to bedside, many groups have started to investigate the use of 3D model systems in their drug development strategies. These systems are thought to be more physiologically relevant because they attempt to recapitulate the complex and heterogeneous environment of a tumor. These systems, however, can be quite complex, and, although amenable to growth in 96-well formats, and some now even in 384, they offer few choices for large-scale growth and screening. This observed gap has led to the development of the methods described here in detail to culture tumor spheroids in a high-throughput capacity in 1536-well plates. These methods represent a compromise to the highly complex matrix-based systems, which are difficult to screen, and conventional 2D assays. A variety of cancer cell lines harboring different genetic mutations are successfully screened, examining compound efficacy by using a curated library of compounds targeting the Mitogen-Activated Protein Kinase or MAPK pathway. The spheroid culture responses are then compared to the response of cells grown in 2D, and differential activities are reported. These methods provide a unique protocol for testing compound activity in a high-throughput 3D setting.

Across a wide variety of disease indications, more physiologically relevant models are being developed and implemented into drug discovery programs. The new model system described here demonstrates how three-dimensional tumor spheroids can be cultured and screened in a high-throughput 1536-well plate-based system to search for new oncology drugs.

Cancer cells have routinely been cultured in two dimensions (2D) on a plastic surface. This technique, however, lacks the true environment a tumor mass is ...

Live-Cell Imaging Assays to Study Glioblastoma Brain Tumor Stem Cell Migration and Invasion

Glioblastoma (GBM) is an aggressive brain tumor that is poorly controlled with the currently available treatment options. Key features of GBMs include rapid proliferation and pervasive invasion into the normal brain. Recurrence is thought to result from the presence of radio- and chemo-resistant brain tumor stem cells (BTSCs) that invade away from the initial cancerous mass and, thus, evade surgical resection. Hence, therapies that target BTSCs and their invasive abilities may improve the otherwise poor prognosis of this disease. Our group and others have successfully established and characterized BTSC cultures from GBM patient samples. These BTSC cultures demonstrate fundamental cancer stem cell properties such as clonogenic self-renewal, multi-lineage differentiation, and tumor initiation in immune-deficient mice. In order to improve on the current therapeutic approaches for GBM, a better understanding of the mechanisms of BTSC migration and invasion is necessary. In GBM, the study of migration and invasion is restricted, in part, due to the limitations of existing techniques which do not fully account for the in vitro growth characteristics of BTSCs grown as neurospheres. Here, we describe rapid and quantitative live-cell imaging assays to study both the migration and invasion properties of BTSCs. The first method described is the BTSC migration assay which measures the migration toward a chemoattractant gradient. The second method described is the BTSC invasion assay which images and quantifies a cellular invasion from neurospheres into a matrix. The assays described here are used for the quantification of BTSC migration and invasion over time and under different treatment conditions.

Here, we describe live-cell imaging techniques to quantitatively measure the migration and invasion of glioblastoma brain tumor stem cells over time and under multiple treatment conditions.

Glioblastoma (GBM) is an aggressive brain tumor that is poorly controlled with the currently available treatment options. Key features of GBMs include ...

Digital Polymerase Chain Reaction Assay for the Genetic Variation in a Sporadic Familial Adenomatous Polyposis Patient Using the Chip-in-a-tube Format

The quantitative analysis of human genetic variation is crucial for understanding the molecular characteristics of serious medical conditions, such as tumors. Because digital polymerase chain reactions (PCR) enable the precise quantification of DNA copy number variants, they are becoming an essential tool for detecting rare genetic variations, such as drug-resistant mutations. It is expected that molecular diagnoses using digital PCR (dPCR) will be available in clinical practice in the near future; thus, how to efficiently conduct dPCR with human genetic material is a hot topic. Here, we introduce a method to detect Adenomatous polyposis coli (APC) somatic mosaicism using dPCR with the chip-in-a-tube format, which allows eight dPCR reactions to be simultaneously conducted. Care should be taken when filling and sealing the reaction mixture on the chips. This article demonstrates how to avoid the over- and underestimation of positive partitions. Furthermore, we present a simple procedure for collecting the dPCR product from the partitions on the chips, which can then be used to confirm the specific amplification. We hope that this methods report will help promote the dPCR with the chip-in-a-tube method in genetic research.

Digital polymerase chain reaction (PCR) is a useful tool for the high-sensitivity detection of single nucleotide variants and DNA copy number variants. Here, we demonstrate key considerations for measuring rare variants in the human genome using digital PCR with the chip-in-a-tube format.

The quantitative analysis of human genetic variation is crucial for understanding the molecular characteristics of serious medical conditions, such as ...

The Clinical Application of Tumor Treating Fields Therapy in Glioblastoma

Glioblastoma is the most common and lethal form of brain cancer, with a median survival of 15 months after diagnosis and a 5 year survival rate of only 5% with current standard of care. Tumors often recur within 9 months following initial surgery, radiation and chemotherapy, at which point treatment options become limited. This highlights the pressing need for the development of better therapeutics to prolong survival and increase the quality of life for these patients.
Tumor Treating Fields (TTFields) therapy was developed to take advantage of the effect of low frequency alternating electrical fields on cells for cancer therapy. TTFields have been demonstrated to disrupt cells during mitosis and slow tumor growth. There is also growing evidence that they act through stimulating immune responses within exposed tumors. The advantages of TTFields therapy include its noninvasive approach and increased quality of life compared to other treatment modalities such as cytotoxic chemotherapies. The Food and Drug Administration approved TTFields therapy for the treatment of recurrent glioblastoma in 2011 and for newly diagnosed glioblastoma in 2015. We report on the effects of TTFields during mitosis, the results of electric fields modeling, and proper transducer array placement. Our protocol outlines the clinical application of TTFields on a patient post-surgery, using the second-generation device.

Glioblastoma is the most common and aggressive primary brain malignancy in adults, with most tumors recurring after initial treatment. Tumor Treating Fields (TTFields) therapy is the newest treatment modality for glioblastoma. Here, we describe the proper application of TTFields-transducer arrays on patients and discuss theory and aspects of treatment.

Glioblastoma is the most common and lethal form of brain cancer, with a median survival of 15 months after diagnosis and a 5 year survival rate of only 5% ...

Longitudinal Intravital Imaging of Brain Tumor Cell Behavior in Response to an Invasive Surgical Biopsy

Biopsies are standard of care for cancer treatment and are clinically beneficial as they allow solid tumor diagnosis, prognosis, and personalized treatment determination. However, perturbation of the tumor architecture by biopsy and other invasive procedures has been associated with undesired effects on tumor progression, which need to be studied in depth to further improve the clinical benefit of these procedures. Conventional static approaches, which only provide a snapshot of the tumor, are limited in their ability to reveal the impact of biopsy on tumor cell behavior such as migration, a process closely related to tumor malignancy. In particular, tumor cell migration is the key in highly aggressive brain tumors, where local tumor dissemination makes total tumor resection virtually impossible. The development of multiphoton imaging and chronic imaging windows allows scientists to study this dynamic process in living animals over time. Here, we describe a method for the high-resolution longitudinal imaging of brain tumor cells before and after a biopsy in the same living animal. This approach makes it possible to study the impact of this procedure on tumor cell behavior (migration, invasion, and proliferation). Furthermore, we discuss the advantages and limitations of this technique, as well as the ability of this methodology to study changes in the cancer cell behavior for other surgical interventions, including tumor resection or the implantation of chemotherapy wafers.

Here we describe a method for high-resolution time-lapse multiphoton imaging of brain tumor cells before and after invasive surgical intervention (e.g., biopsy) within the same living animal. This method allows studying the impact of these invasive surgical procedures on tumor cells&#39; migratory, invasive, and proliferative behavior at a single cell level.

Biopsies are standard of care for cancer treatment and are clinically beneficial as they allow solid tumor diagnosis, prognosis, and personalized ...

Assessing Cell Viability and Death in 3D Spheroid Cultures of Cancer Cells

Three-dimensional spheroids of cancer cells are important tools for both cancer drug screens and for gaining mechanistic insight into cancer cell biology. The power of this preparation lies in its ability to mimic many aspects of the in vivo conditions of tumors while being fast, cheap, and versatile enough to allow relatively high-throughput screening. The spheroid culture conditions can recapitulate the physico-chemical gradients in a tumor, including the increasing extracellular acidity, increased lactate, and decreasing glucose and oxygen availability, from the spheroid periphery to its core. Also, the mechanical properties and cell-cell interactions of in vivo tumors are in part mimicked by this model. The specific properties and consequently the optimal growth conditions, of 3D spheroids, differ widely between different types of cancer cells. Furthermore, the assessment of cell viability and death in 3D spheroids requires methods that differ in part from those employed for 2D cultures. Here we describe several protocols for preparing 3D spheroids of cancer cells, and for using such cultures to assess cell viability and death in the context of evaluating the efficacy of anticancer drugs.

Here, we present several simple methods for evaluating viability and death in 3D cancer cell spheroids, which mimic the physico-chemical gradients of in vivo tumors much better than the 2D culture. The spheroid model, therefore, allows evaluation of the cancer drug efficacy with improved translation to in vivo conditions.

Three-dimensional spheroids of cancer cells are important tools for both cancer drug screens and for gaining mechanistic insight into cancer cell biology. ...

Establishment and Characterization of Small Bowel Neuroendocrine Tumor Spheroids

Small bowel neuroendocrine tumors (SBNETs) are rare cancers originating from enterochromaffin cells of the gut. Research in this field has been limited because very few patient derived SBNET cell lines have been generated. Well-differentiated SBNET cells are slow growing and are hard to propagate. The few cell lines that have been established are not readily available, and after time in culture may not continue to express characteristics of NET cells. Generating new cell lines could take many years since SBNET cells have a long doubling time and many enrichment steps are needed in order to eliminate the rapidly dividing cancer-associated fibroblasts. To overcome these limitations, we have developed a protocol to culture SBNET cells from surgically removed tumors as spheroids in extracellular matrix (ECM). The ECM forms a 3-dimensional matrix that encapsulates SBNET cells and mimics the tumor micro-environment for allowing SBNET cells to grow. Here, we characterized the growth rate of SBNET spheroids and described methods to identify SBNET markers using immunofluorescence microscopy and immunohistochemistry to confirm that the spheroids are neuroendocrine tumor cells. In addition, we used SBNET spheroids for testing the cytotoxicity of rapamycin.

Neuroendocrine tumors (NETs) originate from neuroendocrine cells of the neural crest. They are slow growing and challenging to culture. We present an alternative strategy to grow NETs from the small bowel by culturing them as spheroids. These spheroids have small bowel NET markers and can be used for drug testing.

Small bowel neuroendocrine tumors (SBNETs) are rare cancers originating from enterochromaffin cells of the gut. Research in this field has been limited ...

Analyzing Tumor and Tissue Distribution of Target Antigen Specific Therapeutic Antibody

Monoclonal antibodies are high affinity multifunctional drugs that work by variable independent mechanisms to eliminate cancer cells. Over the last few decades, the field of antibody-drug conjugates, bispecific antibodies, chimeric antigen receptors (CAR) and cancer immunotherapy has emerged as the most promising area of basic and therapeutic investigations. With numerous successful human trials targeting immune checkpoint receptors and CAR-T cells in leukemia and melanoma at a breakthrough pace, it is highly exciting times for oncologic therapeutics derived from variations of antibody engineering. Regrettably, a significantly large numbers of antibody and CAR based therapeutics have also proven disappointing in human trials of solid cancers because of the limited availability of immune effector cells in the tumor bed. Importantly, nonspecific distribution of therapeutic antibodies in tissues other than tumors also contribute to the lack of clinical efficacy, associated toxicity and clinical failure. As faithful translation of preclinical studies into human clinical trails are highly relied on mice tumor xenograft efficacy and safety studies, here we highlight a method to test the tumor and general tissue distribution of therapeutic antibodies. This is achieved by labeling the protein-A purified antibody with near Infrared fluorescent dye followed by live imaging of tumor bearing mice.

Here we present a protocol to study the in vivo localization of antibodies in mice tumor xenograft models.

Monoclonal antibodies are high affinity multifunctional drugs that work by variable independent mechanisms to eliminate cancer cells. Over the last few ...

Rapid Optical Clearing for Semi-High-Throughput Analysis of Tumor Spheroids

Tumor spheroids are fast becoming commonplace in basic cancer research and drug development. Obtaining data regarding protein expression within the spheroid at the cellular level is important for analysis, yet existing techniques are often expensive, laborious, use non-standard equipment, cause significant size distortion, or are limited to relatively small spheroids. This protocol presents a new method of mounting and clearing spheroids that address these issues while allowing for confocal analysis of the inner structure of spheroids. In contrast to existing approaches, this protocol provides for rapid mounting and clearing of a large number of spheroids using standard equipment and laboratory supplies. Mounting spheroids in a pH-neutral agarose-PBS gel solution before introducing a refractive-index-matched clearing solution minimizes size distortion common to other similar techniques. This allows for detailed quantitative and statistical analysis where the accuracy of size measurements is paramount. Furthermore, compared to liquid clearing solutions, the agarose gel technique keeps spheroids fixed in place, allowing for the collection of three-dimensional (3D) confocal images. The present article elaborates how the method yields high-quality two- and 3D images that provide information about inter-cell variability and inner spheroid structure.

Tumor spheroids are becoming increasingly utilized to assess tumor cell-microenvironment interactions and therapy response. The present protocol describes a robust but simple method for semi-high-throughput imaging of 3D tumor spheroids using rapid optical clearing.

Tumor spheroids are fast becoming commonplace in basic cancer research and drug development. Obtaining data regarding protein expression within the ...