We wish to acknowledge the support of the University Of Chicago Section Of Urology led by Dr. Arieh Shalhav, and the Director of Urologic Research Dr. Carrie Rinker-Schaeffer. We would also like to acknowledge the support of the University of Chicago Comprehensive Cancer Center (UCCCC) led by Dr. Michelle Le Beau. We also with to thank expert technical assistance of the Human Tissue Resource Center core facility led by Dr. Mark Lingen, and the assistance of Leslie Martin and Mary Jo Fekete. We also thank the Immunohistochemistry Core Facility run by Terri Li. This work was funded by the University of Chicago Department of Surgery, the Section of Urology; an American Cancer Society Institutional Research Grant (ACS-IRG, #IRG-58-004); a Cancer Center Support Grant (P30 CA14599); The Brinson Foundation; the Alvin Baum Family Fund; The University of Chicago Cancer Research Foundation Women's Board; S. Kregel is supported by an HHMI: Med-into-Grad Fellowship (56006772) and a Cancer Biology Training Grant (T32-CA09594). Finally, we would like to thank Robert Clark, Dr. VenkateshKrishnan, and Nathan Stadick for their critical evaluation of the manuscript.

This study was carried out in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. The protocol was approved by the University of Chicago Institutional Animal Care and Use Committee (IACUC, protocol numbers 72066 and 72231). All surgery was performed under anesthesia, and all efforts were made to minimize suffering. The human embryonic stem cell line WA01 (H1; NIH-registration #0043) was acquired from WiCell (Madison, WI) and cultured using the feeder-independent protocol using mTeSR1 media (Stem Cell Technologies; Vancouver, B.C.). ES cells were used within ten passages of thawing.
1. Isolation of the Urogenital Sinus from Mouse or Rat Embryos
<ol>
	<li>Euthanize a timed-pregnant mouse (day 17.5) or rat (day 18.5) by inhalation of CO2 for 5 min. Death is confirmed by cessation of vital signs in the rat. Then break its neck humanely. The rat is euthanized at this point. Spray 70% ethanol to sterilize the abdominal skin and flanks. Cut the abdominal skin and muscle layers and then cut the uterus, separate the rat embryos from the amniotic sac, and cut the umbilical cord. Transfer the embryos into a 50 ml Falcon tube containing ice-cold Hank's Balanced Salt Solution (HBSS) and keep on ice. Fetuses are euthanized by decapitation with surgical scissors.</li>
	<li>Place the embryo in 100 mm Petri dish. Bisect the embryo with scissors at the level of the umbilicus (Figure 1A). Remove the stomach and small intestine. Reveal the ovaries in the female embryo and testis in the male embryo (Figure 1B and 1C). (The ovaries are located at the caudal poles of the kidneys. The testes are approximately at the level of the bladder). At this developmental stage, UGSM isolated from both male and female embryos are capable of inducing a prostatic epithelial lineage in the presence of host testosterone.4 After this developmental time point, however, prostatic buds begin forming into the UGSM, and isolation of pure UGSM is very challenging.4</li>
	<li>Under the dissection microscope, cut the abdominal wall in the middle line with Vannas scissors to expose the bladder and posterior wall of the abdomen. Free the upper genital tract from attachments (in male embryos, cut the ureter, Wolffian duct and M&uuml;llerian duct; in female embryos, cut the ureter and M&uuml;llerian duct). Free the bladder from the umbilical cord. Cut pubic bone and bluntly separate from the anterior wall of the urogenital sinus with Dumont fine tip forceps. Finally, separate the posterior wall of the urogenital sinus from the rectum. Cut the urogenital sinus with the bladder at the lower end (from the urethra) and store the urogenital sinus en bloc (with the bladder) in ice cold HBSS.</li>
</ol>
2. Separation of the Urogenital Sinus Mesenchyme
<ol>
	<li>Remove the bladder from the urogenital sinus under the dissection microscope (Figure 1D).</li>
	<li>Transfer the urogenital sinus to a falcon tube containing 1% trypsin in Calcium (Ca2+) and Magnesium (Mg2+) free HBSS. Place the tube in a refrigerator at 4 &deg;C for 75 min.</li>
	<li>Remove the trypsin and neutralize trypsinization with 10% Fetal Bovin Serum (FBS) in DMEM/F12 medium.</li>
	<li>Carefully tease the sticky mesenchymal sleeve from the epithelial tube with a needle or Dumont fine tip forceps (maintaining the epithelial tube intact reduces the chances of epithelial cell contamination of the mesenchyme; this can result in rodent glands forming along with your stem cell-derived human glandular epithelium) (Figure 1D).12</li>
	<li>Transfer UGSM into a new Falcon tube containing DMEM/F12 medium + 10% FBS + 1% Penicillin/Streptomycin (Pen/Strep; 0.5 mg/ml) + 1% Non-Essential Amino Acids (NEAA) plus 1nM R1881. Place the tube in an incubator at 37 &deg;C with 5% CO2 overnight.</li>
	<li>Centrifuge the tissue at 200 x g and discard the supernatant. Wash with Phosphate Buffer Saline (PBS) (do not disturb the tissue pellet).</li>
	<li>Add 0.2% collagenase (in DMEM/F12) to re-suspend the tissue. Incubate in 37 &deg;C with gentle rocking for 1 hr.</li>
	<li>Vigorously vortex the digestion tissue three times until it becomes homogenous single-cell mixture and add DMEM/F12 medium + 10% FBS + 1% P/S + 1% NEAA + 1nM R1881 to neutralize the collagenase.</li>
	<li>Centrifuge at 200 x g and then wash by re-suspending the UGSM cells in HBSS, and repeat three times to fully wash the UGSM. Finally suspend mesenchymal cells in DMEM/F12 and count the cells using a hemocytometer or cell counting device.</li>
	<li>Dissociate hES cells cultured using feeder-free protocol with mTeSR1 media (Stem Cell Technologies; Vancouver, B.C.) using an Accutase digestion (Millipore; Billerica, MA). Wash the hES cells during the log phase of their growth in warm DMEM/F12 media, then add warm 1x Accutase solution, and incubate at 37 &deg;C for 15-20 min until single cells are uniformly dissociated from colonies. Add an equal amount of 1x defined Trypsin Inhibitor (Invitrogen; Grand Island, NY) to neutralize the Accutase and gently pipette up and down to mix and break up cell clumps. Pipette cells into a centrifuge tube and centrifuge for 3 min at 200 x g, and re-suspend cell pellet in DMEM/F12 media. Centrifuge tube for 3 min at 200 x g again and remove the supernatant, then re-suspend in cold HBSS or DMEM/F12 at desired volume.</li>
	<li>Add hES cells with 1:2.5 ratio of hES/mesenchymal cells.3 This will be a cellular composition of 1E5 UGSM cells with 4E4 hESCs per 10 ml injection (a single rat UGS typically yields about 2E6 mesenchymal cells). Centrifuge at 200 x g for 5 min and then discard the supernatant. Re-suspend with 75% Matrigel (BD Biosciences, San Jose, CA; mixed with 25% cold HBSS for easier handling) and place the tube in ice for sub-renal capsule injection.</li>
</ol>
3. Transplantation of Tissue Recombinant Underneath the Renal Capsule
<ol>
	<li>Prepare a sterile surgical area.</li>
	<li>Anesthetize a male athymic nude mouse with ketamine/xylazine i.p.; use a fresh mix containing a 1:1:8 ratio of ketamine:xylazine:saline. Dosing will be 100 mg/kg Ketamine and 2.5 mg/kg Xylazine. Animals unresponsive to a toe-pinch should be fully under for 20-30 min.</li>
	<li>Surgically prepare the mouse by shaving the surgical site (if not using a nude mouse), cleansing with three alternating wipes of 70% alcohol followed by betadine solution and applying a surgical drape.</li>
	<li>Put eye moisture salve (Altalube eye ointment) to the eyes of the mouse to prevent drying during anesthesia.</li>
	<li>During surgery, respiration rate and core body temperature of the mice are monitored. The respiration rates should be steady and maintained within 40-90 breaths/min. Core body temperature is monitored with observation of the color of the mucous membranes and the pink soles of the feet. </li>
	<li>Make a 1.0 cm long longitudinal skin incision on the back. Continue to cut the abdominal wall in a 0.5 cm longitudinal incision.</li>
	<li>Gently squeeze the kidney out of the abdomen and keep the kidney surface moist using drops of sterile saline.</li>
	<li>Gently puncture the renal capsule using an empty 27-gauge syringe needle. A very shallow puncture is sufficient. This will be where you insert your blunt needle to inject your cellular mixture.</li>
	<li>Fill a 28-gauge blunt syringe needle with 10 &mu;l of your cell mixture. Slowly insert the puncture site and penetrate the kidney parenchyma to reach an area underneath the renal capsule. Inject 10 &mu;l of the cellular mixture to form a bolus on the kidney underneath the renal capsule. Withdrawal the needle.</li>
	<li>Return the kidney to the abdominal cavity. Secure the muscular layer of the peritoneum with 4-0 nylon sutures.</li>
	<li>Close the skin with either suture or staple.</li>
	<li>Clean blood from the skin using sterile saline.</li>
</ol>
4. Post-operative Analgesia and Monitoring
<ol>
	<li>Inject the animal with buprenorphine (0.1 mg/kg every 12 hr) or ketoprofen (3-5 mg/kg in saline every 12 hr) to manage post-operative pain, and 1 ml of 37 &deg;C saline i.p. to keep the animal warm and prevent dehydration.</li>
	<li>Put the animal in a clean cage and place it on a mild heating pad.</li>
	<li>Send the animals back to animal room once they regain consciousness and are moving within the cage.</li>
	<li>Observe the animal daily for unexpected signs of illness and infection for the following three days. The mice are monitored with observation of activities in cages including accessing food and water 1 day post-operatively. If the mice display fewer activities, Ketoprofen is intraperitoneally administered again once a day.</li>
	<li>Remove the skin staples or sutures 2 weeks post-surgery.</li>
	<li>Xenograft tissues can be harvested as early as 8 weeks post-surgery. Xenografts can be imaged in vivo using small-animal ultrasound (Figure 2A), and fixed tissues can be sectioned and stained for various proteins using immunohistochemistry (Figure 3).</li>
</ol>

<ol>
	<li>Taylor, R. 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=Formation+of+human+prostate+tissue+from+embryonic+stem+cells.">Formation of human prostate tissue from embryonic stem cells.</a> Nat. Methods. 3, 179-181 (2006).</li><li>Cunha, G. R., Chung, L. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stromal-epithelial+interactions--I.+Induction+of+prostatic+phenotype+in+urothelium+of+testicular+feminized+(Tfm/y)+mice.">Stromal-epithelial interactions--I. Induction of prostatic phenotype in urothelium of testicular feminized (Tfm/y) mice.</a> J. Steroid Biochem. 14, 1317-1324 (1981).</li><li>Cunha, G. R., Chung, L. W., Shannon, J. M., Taguchi, O., Fujii, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hormone-induced+morphogenesis+and+growth:+role+of+mesenchymal-epithelial+interactions.">Hormone-induced morphogenesis and growth: role of mesenchymal-epithelial interactions.</a> Recent Prog. Horm. Res. 39, 559-598 (1983).</li><li>Staack, A., Donjacour, A. A., Brody, J., Cunha, G. R., Carroll, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+urogenital+development:+a+practical+approach.">Mouse urogenital development: a practical approach.</a> Differentiation. 71, 402-413 (2003).</li><li>Cunha, G. 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=Normal+and+abnormal+development+of+the+male+urogenital+tract.+Role+of+androgens,+mesenchymal-epithelial+interactions,+and+growth+factors.">Normal and abnormal development of the male urogenital tract. Role of androgens, mesenchymal-epithelial interactions, and growth factors.</a> J. Androl. 13, 465-475 (1992).</li><li>Cunha, G. 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=Growth+factors+as+mediators+of+androgen+action+during+the+development+of+the+male+urogenital+tract.">Growth factors as mediators of androgen action during the development of the male urogenital tract.</a> World J. Urol. 13, 264-276 (1995).</li><li>Aboseif, S., El-Sakka, A., Young, P., Cunha, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mesenchymal+reprogramming+of+adult+human+epithelial+differentiation.">Mesenchymal reprogramming of adult human epithelial differentiation.</a> Differentiation. 65, 113-118 (1999).</li><li>Marker, P. C., Donjacour, A. A., Dahiya, R., Cunha, G. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hormonal,+cellular,+and+molecular+control+of+prostatic+development.">Hormonal, cellular, and molecular control of prostatic development.</a> Dev. Biol. 253, 165-174 (2003).</li><li>Cunha, G. R., Sekkingstad, M., Meloy, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterospecific+induction+of+prostatic+development+in+tissue+recombinants+prepared+with+mouse,+rat,+rabbit+and+human+tissues.">Heterospecific induction of prostatic development in tissue recombinants prepared with mouse, rat, rabbit and human tissues.</a> Differentiation. 24, 174-180 (1983).</li><li>Van der Griend, D. 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=The+Role+of+CD133+in+Normal+Human+Prostate+Stem+Cells+and+Malignant+Cancer+Initiating+Cells.">The Role of CD133 in Normal Human Prostate Stem Cells and Malignant Cancer Initiating Cells.</a> Cancer Res. 68, 9703-9711 (2008).</li><li>Van der Griend, D. J., Konishi, Y., De Marzo, A. M., Isaacs, J. T., Meeker, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dual-label+centromere+and+telomere+FISH+identifies+human,+rat,+and+mouse+cell+contribution+to+Multispecies+recombinant+urogenital+sinus+xenografts.">Dual-label centromere and telomere FISH identifies human, rat, and mouse cell contribution to Multispecies recombinant urogenital sinus xenografts.</a> Prostate. , (2009).</li><li>Vander Griend, D. J., Konishi, Y., De Marzo, A. M., Isaacs, J. T., Meeker, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dual-label+centromere+and+telomere+FISH+identifies+human,+rat,+and+mouse+cell+contribution+to+Multispecies+recombinant+urogenital+sinus+xenografts.">Dual-label centromere and telomere FISH identifies human, rat, and mouse cell contribution to Multispecies recombinant urogenital sinus xenografts.</a> Prostate. 69, 1557-1564 (2009).</li><li>Thomson, J. 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=Embryonic+stem+cell+lines+derived+from+human+blastocysts.">Embryonic stem cell lines derived from human blastocysts.</a> Science. 282, 1145-1147 (1998).</li><li>Ludwig, T. 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=Feeder-independent+culture+of+human+embryonic+stem+cells.">Feeder-independent culture of human embryonic stem cells.</a> Nat. Methods. 3, 637-646 (2006).</li><li>Prokhorova, T. 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=Teratoma+formation+by+human+embryonic+stem+cells+is+site+dependent+and+enhanced+by+the+presence+of+Matrigel.">Teratoma formation by human embryonic stem cells is site dependent and enhanced by the presence of Matrigel.</a> Stem Cells Dev. 18, 47-54 (2009).</li><li>Hameed, O., Sublett, J., Humphrey, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunohistochemical+stains+for+p63+and+alpha-methylacyl-CoA+racemase,+versus+a+cocktail+comprising+both,+in+the+diagnosis+of+prostatic+carcinoma:+a+comparison+of+the+immunohistochemical+staining+of+430+foci+in+radical+prostatectomy+and+needle+biopsy+tissues.">Immunohistochemical stains for p63 and alpha-methylacyl-CoA racemase, versus a cocktail comprising both, in the diagnosis of prostatic carcinoma: a comparison of the immunohistochemical staining of 430 foci in radical prostatectomy and needle biopsy tissues.</a> Am. J. Surg. Pathol. 29, 579-587 (2005).</li><li>Wang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+human+prostatic+epithelial+model+of+hormonal+carcinogenesis.">A human prostatic epithelial model of hormonal carcinogenesis.</a> Cancer Res. 61, 6064-6072 (2001).</li><li>Yao, V., Parwani, A., Maier, C., Heston, W. D., Bacich, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Moderate+expression+of+prostate-specific+membrane+antigen,+a+tissue+differentiation+antigen+and+folate+hydrolase,+facilitates+prostate+carcinogenesis.">Moderate expression of prostate-specific membrane antigen, a tissue differentiation antigen and folate hydrolase, facilitates prostate carcinogenesis.</a> Cancer Res. 68, 9070-9077 (2008).</li><li>Cunha, G. R., Cooke, P. S., Kurita, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+stromal-epithelial+interactions+in+hormonal+responses.">Role of stromal-epithelial interactions in hormonal responses.</a> Arch. Histol. Cytol. 67, 417-434 (2004).</li><li>Xin, L., Ide, H., Kim, Y., Dubey, P., Witte, O. N. <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+regeneration+of+murine+prostate+from+dissociated+cell+populations+of+postnatal+epithelia+and+urogenital+sinus+mesenchyme.">In vivo regeneration of murine prostate from dissociated cell populations of postnatal epithelia and urogenital sinus mesenchyme.</a> Proc. Natl. Acad. Sci. U.S.A. 100, 11896-11903 (2003).</li><li>Yu, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lentiviral+vectors+with+two+independent+internal+promoters+transfer+high-level+expression+of+multiple+transgenes+to+human+hematopoietic+stem-progenitor+cells.">Lentiviral vectors with two independent internal promoters transfer high-level expression of multiple transgenes to human hematopoietic stem-progenitor cells.</a> Mol. Ther. 7, 827-838 (2003).</li><li>Anderson, J. S., Bandi, S., Kaufman, D. S., Akkina, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Derivation+of+normal+macrophages+from+human+embryonic+stem+(hES)+cells+for+applications+in+HIV+gene+therapy.">Derivation of normal macrophages from human embryonic stem (hES) cells for applications in HIV gene therapy.</a> Retrovirology. 3, 24 (2006).</li><li>Takahashi, K., Yamanaka, S. <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+pluripotent+stem+cells+from+mouse+embryonic+and+adult+fibroblast+cultures+by+defined+factors.">Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors.</a> Cell. 126, 663-676 (2006).</li><li>Maherali, 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=A+high-efficiency+system+for+the+generation+and+study+of+human+induced+pluripotent+stem+cells.">A high-efficiency system for the generation and study of human induced pluripotent stem cells.</a> Cell Stem Cell. 3, 340-345 (2008).</li></ol>

The authors have no conflict of interest with the work presented.

Tissue recombination using UGSM is an incredibly useful technique to investigate the development of the prostate and the molecular events leading to prostate cancer initiation. The inductive potential of UGSM has been used for numerous applications in prostate research; these include enhancing tumor take of prostate cell lines and tumors, studying stromal-epithelial interactions, and forming cross-species prostate recombinants.7,17-20 Proper preparation of UGSM, however, is critical to experimental succ...

There is a tremendous need for better human model systems of prostate cancer. In particular, relevant human model systems of normal, non-malignant prostate tissues which can be genetically manipulated to directly discern the role of specific genes in the initiation of prostate cancer would be incredibly informative. The advent of the genomic era has identified numerous genes which may have a role in cancer formation. A lack of experimental human model systems, however, severely impairs our ability to functionally test and characterize candidate prostate cancer susceptibility genes. An ideal model system would facilitate the rapid and more rapid functional analyses of cancer susceptibility genes in combination with appropriate transgenic rodent model systems. Furthermore, such a human model system would enable molecular characterization of the signaling mechanisms of prostate carcinogenesis toward the discovery and validation of novel therapies to prevent prostate cancer formation.
Human embryonic stem cells (hESCs) are capable of forming human prostatic tissues as xenografts. In 2006 Taylor, et al. reported that hESCs can be induced to form prostatic epithelia in vivo when re-combined with rodent urogenital sinus mesenchyme (UGSM) within a time period of 8-12 weeks.1 These studies were based upon previous work by the Cunha lab showing that rodent embryonic UGSM can promote prostatic differentiation of stem cells and embryonic epithelial cell populations in vivo.2,3 The prostate develops from an embryonic anlagen termed the urogenital sinus (UGS), and prior to embryonic day 17 (mouse E17; day E18 in the rat) the UGS can be removed and physically divided into epithelium (UGSE) and mesenchyme (UGSM).4 This tissue recombination approach has significantly enhanced our understanding of prostate development and carcinogenesis, particularly growth factor and hormonal signaling pathways and the molecular relationships between prostate stroma and epithelium.5-8 This method involves the ex vivo combination of UGSM with stem or epithelial cells from the same or distinct species and these cellular/tissue recombinants are implanted and grown and xenografts within mouse host.4,9 After a period of in vivo growth, the implant contains prostate epithelial glandular structures embedded in stromal tissue. Further staining can be conducted to determine whether such structures are truly prostatic and of human origin.10,11

<table border="1">
 <tbody>
 <tr>
 <td>Name</td>
 <td>Company</td>
 <td>Catalogue Number</td>
 <td>Comments</td>
 </tr>
 <tr>
 <td>Hank's Balanced Salt Solution (HBSS)</td>
 <td>GIBCO</td>
 <td>14170</td>
 <td></td>
 </tr>
 <tr>
 <td>DMEM/F12</td>
 <td>GIBCO</td>
 <td>11330</td>
 <td></td>
 </tr>
 <tr>
 <td>R1881</td>
 <td>Sigma</td>
 <td>965-93-5</td>
 <td>Mix to 1 ug/ml in Ethanol (1,000x stock)</td>
 </tr>
 <tr>
 <td>NEAA</td>
 <td>GIBCO</td>
 <td>11140</td>
 <td></td>
 </tr>
 <tr>
 <td>Pen-Strep Solution</td>
 <td>GIBCO</td>
 <td>15070</td>
 <td>100x stock</td>
 </tr>
 <tr>
 <td>Matrigel</td>
 <td>BD Biosciences</td>
 <td>354230</td>
 <td></td>
 </tr>
 <tr>
 <td>KETASET (ketamine hydrochloride) </td>
 <td>Fort Dodge Animal Health</td>
 <td>NDC 0856-2013-01</td>
 <td>100 mg/ml; dilute 1:10 in sterile saline </td>
 </tr>
 <tr>
 <td>AnaSed (xylazine) </td>
 <td>VET-A-MIX, Inc.</td>
 <td>NADA 139-236</td>
 <td>20 mg/ml; dilute 1:10 in sterile saline</td>
 </tr>
 <tr>
 <td>Trypsin</td>
 <td>BD Biosciences</td>
 <td>215240</td>
 <td></td>
 </tr>
 <tr>
 <td>Collagenase </td>
 <td>Sigma</td>
 <td>C2014</td>
 <td></td>
 </tr>
 <tr>
 <td>Ketoprofen </td>
 <td>Fort Dodge</td>
 <td>NDC 0856-4396-01</td>
 <td>100 mg/ml; dilute 1:1,000 in sterile saline</td>
 </tr>
 <tr>
 <td>Altalube eye ointment </td>
 <td>Altaire Pharmaceuticals, Inc.</td>
 <td>NLC 56641-19850</td>
 <td></td>
 </tr>
 <tr>
 <td>Leica MZ16 F Stereomicroscope</td>
 <td>Leica</td>
 <td></td>
 <td>Any good dissecting scope can be used.</td>
 </tr>
 <tr>
 <td>Vannas spring scissors</td>
 <td>Fine Science Tools</td>
 <td>15001-08</td>
 <td></td>
 </tr>
 <tr>
 <td>Syringe</td>
 <td>Hamilton</td>
 <td>84855</td>
 <td></td>
 </tr>
 <tr>
 <td>Hamilton Needle, Small RN, 28 gauge, 0.5inches, Point Style #3 (Blunt)</td>
 <td>Hamilton</td>
 <td>7803-02 </td>
 <td>Custom Needle </td>
 </tr>
 <tr>
 <td>Ethanol Prep Pads</td>
 <td>Fisher Scientific</td>
 <td>06-669-62 </td>
 <td></td>
 </tr>
 <tr>
 <td>Sterile Gauze Pads</td>
 <td>Fisher Scientific</td>
 <td>22-415-469 </td>
 <td></td>
 </tr>
 <tr>
 <td>Ethicon Vicryl Suture (4-0 FS-2)</td>
 <td>MedVet International</td>
 <td>J392H </td>
 <td>Needle-in, dissolvable suture </td>
 </tr>
 <tr>
 <td>Autoclip 9 mm Wound Clips</td>
 <td>Becton Dickenson</td>
 <td>427631</td>
 <td></td>
 </tr>
 <tr>
 <td>PVP Iodine Prep Pads</td>
 <td>Fisher Scientific</td>
 <td>06-669-98 </td>
 <td></td>
 </tr>
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formation of human prostate epithelium using tissue recombination of rodent urogenital sinus mesenchyme and human stem cells

Progress in prostate cancer research is severely limited by the availability of human-derived and hormone-na&iuml;ve model systems, which limit our ability to understand genetic and molecular events underlying prostate disease initiation. Toward developing better model systems for studying human prostate carcinogenesis, we and others have taken advantage of the unique pro-prostatic inductive potential of embryonic rodent prostate stroma, termed urogenital sinus mesenchyme (UGSM). When recombined with certain pluripotent cell populations such as embryonic stem cells, UGSM induces the formation of normal human prostate epithelia in a testosterone-dependent manner. Such a human model system can be used to investigate and experimentally test the ability of candidate prostate cancer susceptibility genes at an accelerated pace compared to typical rodent transgenic studies. Since Human embryonic stem cells (hESCs) can be genetically modified in culture using inducible gene expression or siRNA knock-down vectors prior to tissue recombination, such a model facilitates testing the functional consequences of genes, or combinations of genes, which are thought to promote or prevent carcinogenesis.
The technique of isolating pure populations of UGSM cells, however, is challenging and learning often requires someone with previous expertise to personally teach. Moreover, inoculation of cell mixtures under the renal capsule of an immunocompromised host can be technically challenging. Here we outline and illustrate proper isolation of UGSM from rodent embryos and renal capsule implantation of tissue mixtures to form human prostate epithelium. Such an approach, at its current stage, requires in vivo xenografting of embryonic stem cells; future applications could potentially include in vitro gland formation or the use of induced pluripotent stem cell populations (iPSCs).

Building on the exciting report by Taylor, et al., our lab has developed an engrafting protocol using the commonly used H1 (NIH-designated WA01, genetically male) human embryonic stem cell line.1 This line has been rigorously tested for quality control and is karyotypically normal.13 When cultured appropriately, hES cells can be maintained, expanded, and cryopreserved in an undifferentiated and pluripotent state using a feeder-free culture method (feeder-free systems commercially availa...

Watch this Scientific Journal Video about Formation of Human Prostate Epithelium Using Tissue Recombination of Rodent Urogenital Sinus Mesenchyme and Human Stem Cells at JoVE.com

Formation of Human Prostate Epithelium Using Tissue Recombination of Rodent Urogenital Sinus Mesenchyme and Human Stem Cells

To unravel the earliest molecular mechanisms underlying prostate cancer initiation, novel and innovative human model systems and approaches are desperately needed. The potential of pre-prostatic urogenital sinus mesenchyme (UGSM) to induce pluripotent stem cell populations to form human prostate epithelium is a powerful experimental tool in prostate research.

Progress in prostate cancer research is severely  limited by the availability of human-derived and hormone-na&iuml;ve model systems,  which limit our ...

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Research

JoVE Journal

Medicine

13.6K Views.  University of Chicago. To unravel the earliest molecular mechanisms underlying prostate cancer initiation, novel and innovative human model systems and approaches are desperately needed. The potential of pre-prostatic urogenital sinus mesenchyme (UGSM) to induce pluripotent stem cell populations to form human prostate epithelium is a powerful experimental tool in prostate research.

Video: Formation of Human Prostate Epithelium Using Tissue Recombination of Rodent Urogenital Sinus Mesenchyme and Human Stem Cells

Stem Cell Transplantation in an in vitro Simulated Ischemia/Reperfusion Model

Stem cell transplantation protocols are finding their way into clinical practice1,2,3. Getting better results, making the protocols more robust, and finding new sources for implantable cells are the focus of recent research4,5. Investigating the effectiveness of cell therapies is not an easy task and new tools are needed to investigate the mechanisms involved in the treatment process6. We designed an experimental protocol of ischemia/reperfusion in order to allow the observation of cellular connections and even subcellular mechanisms during ischemia/reperfusion injury and after stem cell transplantation and to evaluate the efficacy of cell therapy. H9c2 cardiomyoblast cells were placed onto cell culture plates7,8. Ischemia was simulated with 150 minutes in a glucose free medium with oxygen level below 0.5%. Then, normal media and oxygen levels were reintroduced to simulate reperfusion. After oxygen glucose deprivation, the damaged cells were treated with transplantation of labeled human bone marrow derived mesenchymal stem cells by adding them to the culture. Mesenchymal stem cells are preferred in clinical trials because they are easily accessible with minimal invasive surgery, easily expandable and autologous. After 24 hours of co-cultivation, cells were stained with calcein and ethidium-homodimer to differentiate between live and dead cells. This setup allowed us to investigate the intercellular connections using confocal fluorescent microscopy and to quantify the survival rate of postischemic cells by flow cytometry. Confocal microscopy showed the interactions of the two cell populations such as cell fusion and formation of intercellular nanotubes. Flow cytometry analysis revealed 3 clusters of damaged cells which can be plotted on a graph and analyzed statistically. These populations can be investigated separately and conclusions can be drawn on these data on the effectiveness of the simulated therapeutical approach.

Stem Cell Transplantation in an in vitro Simulated Ischemia/Reperfusion Model

We demonstrate how to set up an in vitro ischemia/reperfusion model and how to evaluate the effect of stem cell therapy on postischemic cardiac cells.

Stem cell transplantation protocols are finding their way into clinical practice1,2,3. Getting better results, making the protocols more robust, and ...

Subretinal Injection of Gene Therapy Vectors and Stem Cells in the Perinatal Mouse Eye

The loss of sight affects approximately 3.4 million people in the United States and is expected to increase in the upcoming years.1 Recently, gene therapy and stem cell transplantations have become key therapeutic tools for treating blindness resulting from retinal degenerative diseases. Several forms of autologous transplantation for age-related macular degeneration (AMD), such as iris pigment epithelial cell transplantation, have generated encouraging results, and human clinical trials have begun for other forms of gene and stem cell therapies.2 These include RPE65 gene replacement therapy in patients with Leber's congenital amaurosis and an RPE cell transplantation using human embryonic stem (ES) cells in Stargardt's disease.3-4 Now that there are gene therapy vectors and stem cells available for treating patients with retinal diseases, it is important to verify these potential therapies in animal models before applying them in human studies. The mouse has become an important scientific model for testing the therapeutic efficacy of gene therapy vectors and stem cell transplantation in the eye.5-8 In this video article, we present a technique to inject gene therapy vectors or stem cells into the subretinal space of the mouse eye while minimizing damage to the surrounding tissue.

This surgical technique illustrates the injection of gene therapy vectors and stem cells into the subretinal space of the mouse eye.

The loss of sight affects approximately 3.4 million people in the United States and is expected to increase in the upcoming years.1 Recently, gene therapy ...

Isolation, Characterization and Comparative Differentiation of Human Dental Pulp Stem Cells Derived from Permanent Teeth by Using Two Different Methods

Developing wisdom teeth are easy-accessible source of stem cells during the adulthood which could be obtained by routine orthodontic treatments. Human pulp-derived stem cells (hDPSCs) possess high proliferation potential with multi-lineage differentiation capacity compare to the ordinary source of adult stem cells1-8; therefore, hDPSCs could be the good candidates for autologous transplantation in tissue engineering and regenerative medicine. Along with these benefits, possessing the mesenchymal stem cells (MSC) features, such as immunolodulatory effect, make hDPSCs more valuable, even in the case of allograft transplantation6,9,10. Therefore, the primary step for using this source of stem cells is to select the best protocol for isolating hDPSCs from pulp tissue. In order to achieve this goal, it is crucial to investigate the effect of various isolation conditions on different cellular behaviors, such as their common surface markers &amp; also their differentiation capacity.
Thus, here we separate human pulp tissue from impacted third molar teeth, and then used both existing protocols based on literature, for isolating hDPSCs,11-13 i.e. enzymatic dissociation of pulp tissue (DPSC-ED) or outgrowth from tissue explants (DPSC-OG). In this regards, we tried to facilitate the isolation methods by using dental diamond disk. Then, these cells characterized in terms of stromal-associated Markers (CD73, CD90, CD105 &amp; CD44), hematopoietic/endothelial Markers (CD34, CD45 &amp; CD11b), perivascular marker, like CD146 and also STRO-1. Afterwards, these two protocols were compared based on the differentiation potency into odontoblasts by both quantitative polymerase chain reaction (QPCR) &amp; Alizarin Red Staining. QPCR were used for the assessment of the expression of the mineralization-related genes (alkaline phosphatase; ALP, matrix extracellular phosphoglycoprotein; MEPE &amp; dentin sialophosphoprotein; DSPP).14

The method described isolation and characterization of human Dental Pulp Stem Cells (hDPSCs) by using either enzymatic dissociation of pulp (DPSC-ED) or direct outgrowth of stem cells from pulp tissue explants (DPSC-OG). Then followed by in vitro comparative differentiation of both types of hDPSCs into odontoblasts.

Developing wisdom teeth are easy-accessible source of stem cells during the adulthood which could be obtained by routine orthodontic treatments. Human ...

An Orthotopic Murine Model of Human Prostate Cancer Metastasis

Our laboratory has developed a novel orthotopic implantation model of human prostate cancer (PCa). As PCa death is not due to the primary tumor, but rather the formation of distinct metastasis, the ability to effectively model this progression pre-clinically is of high value. In this model, cells are directly implanted into the ventral lobe of the prostate in Balb/c athymic mice, and allowed to progress for 4-6 weeks. At experiment termination, several distinct endpoints can be measured, such as size and molecular characterization of the primary tumor, the presence and quantification of circulating tumor cells in the blood and bone marrow, and formation of metastasis to the lung. In addition to a variety of endpoints, this model provides a picture of a cells ability to invade and escape the primary organ, enter and survive in the circulatory system, and implant and grow in a secondary site. This model has been used effectively to measure metastatic response to both changes in protein expression as well as to response to small molecule therapeutics, in a short turnaround time.

This orthotopic model of human prostate cancer allows for quantification of tumor size, circulating tumor cells, and formation of distinct metastasis to the lung. As cells must escape the primary organ, enter the blood stream, and implant into a secondary site, this model effectively recapitulates the scenario in humans.

Our laboratory has developed a novel orthotopic implantation model of  human prostate cancer (PCa). As PCa death is not due to the primary tumor, but  ...

Isolation of Cancer Stem Cells From Human Prostate Cancer Samples

The cancer stem cell (CSC) model has been considerably revisited over the last two decades. During this time CSCs have been identified and directly isolated from human tissues and serially propagated in immunodeficient mice, typically through antibody labeling of subpopulations of cells and fractionation by flow cytometry. However, the unique clinical features of prostate cancer have considerably limited the study of prostate CSCs from fresh human tumor samples. We recently reported the isolation of prostate CSCs directly from human tissues by virtue of their HLA class I (HLAI)-negative phenotype. Prostate cancer cells are harvested from surgical specimens and mechanically dissociated. A cell suspension is generated and labeled with fluorescently conjugated HLAI and stromal antibodies. Subpopulations of HLAI-negative cells are finally isolated using a flow cytometer. The principal limitation of this protocol is the frequently microscopic and multifocal nature of primary cancer in prostatectomy specimens. Nonetheless, isolated live prostate CSCs are suitable for molecular characterization and functional validation by transplantation in immunodeficient mice.

The isolation of cancer stem cells (CSCs) directly from human tissues is requisite for their biological characterization. This manuscript describes a methodology for the isolation of prostate CSCs from human tissues, while also providing tips on troubleshooting difficult steps.

The cancer stem cell (CSC) model has been considerably revisited over the last two decades. During this time CSCs have been identified and directly ...

Enrichment for Chemoresistant Ovarian Cancer Stem Cells from Human Cell Lines

Cancer stem cells (CSCs) are defined as a subset of slow cycling and undifferentiated cells that divide asymmetrically to generate highly proliferative, invasive, and chemoresistant tumor cells. Therefore, CSCs are an attractive population of cells to target therapeutically. CSCs are predicted to contribute to a number of types of malignancies including those in the blood, brain, lung, gastrointestinal tract, prostate, and ovary. Isolating and enriching a tumor cell population for CSCs will enable researchers to study the properties, genetics, and therapeutic response of CSCs. We generated a protocol that reproducibly enriches for ovarian cancer CSCs from ovarian cancer cell lines (SKOV3 and OVCA429). Cell lines are treated with 20 &#181;M cisplatin for 3 days. Surviving cells are isolated and cultured in a serum-free stem cell media containing cytokines and growth factors. We demonstrate an enrichment of these purified CSCs by analyzing the isolated cells for known stem cell markers Oct4, Nanog, and Prom1 (CD133) and cell surface expression of CD177 and CD133. The CSCs exhibit increased chemoresistance. This method for isolation of CSCs is a useful tool for studying the role of CSCs in chemoresistance and tumor relapse.

Cancer stem cells (CSCs) are&#160;implicated in tumor relapse due to chemoresistance. We have optimized a protocol for selection and expansion of CSCs from ovarian cancer cell lines. By treating cells with the chemotherapeutic cisplatin and culturing&#160;in a stem cell promoting media we enrich for non-adherent CSC cultures.

Cancer stem cells (CSCs) are defined as a subset of slow cycling and undifferentiated cells that divide asymmetrically to generate highly proliferative, ...

Evaluation of Stem Cell Properties in Human Ovarian Carcinoma Cells Using Multi and Single Cell-based Spheres Assays

Years of research indicates that ovarian cancers harbor a heterogeneous mixture of cells including a subpopulation of so-called &#8220;cancer stem cells&#8221; (CSCs) responsible for tumor initiation, maintenance and relapse following conventional chemotherapies. Identification of ovarian CSCs is therefore an important goal. A commonly used method to assess CSC potential in vitro is the spheres assay in which cells are plated under non-adherent culture conditions in serum-free medium supplemented with growth factors and sphere formation is scored after a few days. Here, we review currently available protocols for human ovarian cancer spheres assays and perform a side-by-side analysis between commonly used multi cell-based assays and a more accurate system based on single cell plating. Our results indicate that both multi cell-based as well as single cell-based spheres assays can be used to investigate sphere formation in vitro. The more laborious and expensive single cell-based assays are more suitable for functional assessment of individual cells and lead to overall more accurate results while multi cell-based assays can be strongly influenced by the density of plated cells and require titration experiments upfront. Methylcellulose supplementation to multi cell-based assays can be effectively used to reduce mechanical artifacts.

In vitro spheres assays are commonly used to identify cancer stem cells. Here we compare single with multi cell-based spheres assays. The more laborious single cell-based assays or methylcellulose supplementation give more accurate results while multi cell-based assays performed in liquid medium can be highly influenced by cell density.

Years of research indicates that ovarian cancers harbor a heterogeneous mixture of cells including a subpopulation of so-called &#8220;cancer stem ...

Laser-capture Microdissection of Human Prostatic Epithelium for RNA Analysis

The prostate gland contains a heterogeneous milieu of stromal, epithelial, neuroendocrine and immune cell types. Healthy prostate is comprised of fibromuscular stroma surrounding discrete epithelial-lined secretory lumens and a very small population of immune and neuroendocrine cells. In contrast, areas of prostate cancer have increased dysplastic luminal epithelium with greatly reduced or absent stromal population. Given the profound difference between stromal and epithelial cell types, it is imperative to separate the cell types for any type of downstream molecular analysis. Despite this knowledge, the bulk of gene expression studies compare benign prostate to cancer without micro-dissection, leading to stromal bias in the benign samples. Laser-capture micro-dissection (LCM) is an effective method to physically separate different cell types from a specimen section. The goal of this protocol is to show that RNA can be successfully isolated from LCM-collected human prostatic epithelium and used for downstream gene expression studies such as RT-qPCR and RNAseq.

The goal of this protocol is to use laser-capture micro-dissection as an effective method to isolate pure populations of cell types from heterogeneous prostate tissues for downstream RNA analysis.

The prostate gland contains a heterogeneous milieu of stromal, epithelial, neuroendocrine and immune cell types.  Healthy prostate is comprised of ...

Pre-clinical Orthotopic Murine Model of Human Prostate Cancer

To study the multifaceted biology of prostate cancer, pre-clinical in vivo models offer a range of options to uncover critical biological information about this disease. The human orthotopic prostate cancer xenograft mouse model provides a useful alternative approach for understanding the specific interactions between genetically and molecularly altered tumor cells, their organ microenvironment, and for evaluation of efficacy of therapeutic regimens. This is a well characterized model designed to study the molecular events of primary tumor development and it recapitulates the early events in the metastatic cascade prior to embolism and entry of tumor cells into the circulation. Thus it allows elucidation of molecular mechanisms underlying the initial phase of metastatic disease. In addition, this model can annotate drug targets of clinical relevance and is a valuable tool to study prostate cancer progression. In this manuscript we describe a detailed procedure to establish a human orthotopic prostate cancer xenograft mouse model.

Prostate cancer is the second most common cause of cancer-related deaths in the United States. An orthotopic cancer model provides a useful approach to understand the biology of prostate cancer and to evaluate the efficacy of therapeutic regimens. This protocol describes detailed steps necessary to establish an orthotopic prostate cancer mouse model.

To study the multifaceted biology of prostate cancer, pre-clinical in vivo models offer a range of options to uncover critical biological information ...

Generation of a Humanized Mouse Liver Using Human Hepatic Stem Cells

A novel animal model involving chimeric mice with humanized livers established via human hepatocyte transplantation has been developed. These mice, in which the liver has been repopulated with functional human hepatocytes, could serve as a useful tool for investigating human hepatic cell biology, drug metabolism, and other preclinical applications. One of the key factors required for successful transplantation of human hepatocytes into mice is the elimination of the endogenous hepatocytes to prevent competition with the human cells and provide a suitable space and microenvironment for promoting human donor cell expansion and differentiation. To date, two major liver injury mouse models utilizing fumarylacetoacetate hydrolase (Fah) and uroplasminogen activator (uPA) mice have been established. However, Fah mice are used mainly with mature hepatocytes and the application of the uPA model is limited by decreased breeding. To overcome these limitations, Alb-toxin receptor mediated cell knockout (TRECK)/SCID mice were used for in vivo differentiation of immature human hepatocytes and humanized liver generation. Human hepatic stem cells (HpSCs) successfully repopulated the livers of Alb-TRECK/SCID mice that had developed lethal fulminant hepatic failure following diphtheria toxin (DT) treatment. This model of a humanized liver in Alb-TRECK/SCID mice will have functional applications in studies involving drug metabolism and drug-drug interactions and will promote other in vivo and in vitro studies.

Here, we present a novel humanized mouse liver model generated in Alb-toxin receptor mediated cell knockout (TRECK)/SCID mice following the transplantation of immature and expandable human hepatic stem cells.

A novel animal model involving chimeric mice with humanized livers established via human hepatocyte transplantation has been developed. These mice, in ...