Expression of Nkx3.1 enhances 17β-estradiol anti-tumor action in PC3 human prostate cancer cells

Aim： To explore whether the anti-tumor action of 17β-estradiol is enhanced by re-expression of the homeodomain transcription factor Nkx3.1 in PC3 human prostate cancer cells. Methods： PC3 cells were stably transfected with pcDNA3.1-Nkx3.1-His vector, which carries a full-length cDNA of human Nkx3.1. The PC3 cells stably transfected with vector pcDNA3.1 were set as a control. The expression of Nkx3.1 protein in the cells was confirmed by Western blot analysis. The effect of Nkx3.1 on cell proliferation of PC3 cells was examined with MTT assay. The antiproliferative and apoptotic effects of 17β-estradiol alone or in combination with Nkx3.1 were estimated on PC3 cells by using MTT growth tests and flow cytometric analyses. The expression of apoptosis-related proteins was analyzed using Western blotting. Results： The plasmid carrying Nkx3.1 gene induced high expression of Nkx3.1 protein in PC3 cells. The re-expression of exogenous Nkx3.1 did not cause a significant reduction in cellular proliferation, whereas the expression of Nkx3.1 enhanced the 17β-estradiol anti-proliferative effect in PC3 cells. Nkx3.1 expres- sion promoted 17β-estradiol-induced apoptosis of PC3 cells, as shown by analysis of Bcl-2, Bax, Caspase-3 and poly （ADP-ribose） polymerase expression. Conclusion： The present study demonstrates that re-expression of Nkx3.1 enhances 17β-estradiol anti-tumor action in PC3 human prostate cancer cells. The in vitro study suggests that re- expression of Nkx3.1 is worthy of further consideration as an adjuvant treatment of androgen independent prostate cancer with estrogen anti-tumor therapies.

Prostate Specific Antigen Promoter-Driven Adenovirus-Mediated Expression of Both ODC and AdoMetDC Antisenses Inhibit Prostate Cancer Growth

Objective：To generate recombinant adenovirus that could simultaneously express ornithine decarboxylase（ODC） and S-adenosylmethionine decarboxylase（AdoMetDC） antisenses specifically in prostate cancer cells,and evaluate its inhibitory effect on prostate cancer in vivo.Methods：Fragments of ODC and AdoMetDC genes were generated by PCR,cloned into the pPGL-PSES,and then recombined with pAdEasy-1 vectors in AdEasy-1 cells.Ad-PSES-ODC-AdoMetDCas virus was produced in HEK293 cells.Following transfection with Ad-PSES-ODC-AdoMetDCas,the levels of ODC or AdoMetDC were determined by RT-PCR and western blot assays.The effect of Ad-PSES-ODC-AdoMetDCas treatment on tumor formation and growth was evaluated in xenograft models of prostate cancers in vivo.Results：The plasmid pAdEasy-PSES-ODC-AdoMetDCas was successfully constructed and the recombinant Ad-PSES-ODC-AdoMetDCas adenovirus was produced.Transfection with Ad-PSES-ODC-AdoMetDCas adenovirus significantly inhibited the expression of ODC and AdoMetDC genes specifically in prostate DU145 cells,but not H1299,HT29 and HepG2 cancer cells,and disrupted the ability of DU145 cells to form solid prostate cancer in vivo.Intratumoral treatment with Ad-PSES-ODC-AdoMetDCas adenovirus significantly inhibited the growth of engrafted prostate tumors in vivo.Conclusion：The recombinant Ad-PSES-ODC-AdoMetDCas adenovirus specifically reduces the expression of both ODC and AdoMetDC genes in prostate cells and may be used for treatment of prostate cancers at the clinic.

Androgen receptor functioned as a suppressor in the prostate cancer cell line PC3 in vitro and in vivo

Background Prostate cancer is one of the most common urogenital tumors in the world with an increasing incidence in China. Androgen deprivation therapy is the major therapeutic option for advanced prostate cancer. However, the role of androgen receptor （AR） in hormone-refractory prostate cancer still remains unclear. This work aimed to investigate the role of AR in an androgen independent prostate cancer cell line by in vitro and in vivo studies. Methods The role of AR in the proliferation and invasion/metastasis ability of PC3-AR9 （a PC3 stable clone expressing human AR driven by natural human AR promoter） were examined with M-IF assay, soft agar assay, chamber invasion assay, wound healing assay, and also with orthotopic xenograft mouse model. Results Restoring androgen receptor in PC3 cells resulted in decreased proliferation and invasion/metastasis ability in MTT, soft agar, chamber invasion and wound healing assay. In the mouse orthotopic xenograft model, PC3-AR9 resulted in smaller primary tumors and metastasis tumors, with a lower proliferation rate and higher apoptosis rate. Conclusion The AR might function as a tumor suppressor in PC3 cells both in vitro and in vivo.