| Prostate cancer is the most epidemic diagnosed cancer and the second leading cause of cancer death in American males. With the improvement of diagnostic techniques,prostate cancer is enable to be diagnosed in earlier stage, and it can be cured, or its progression can be controlled successfully by several medical treatments, including radical prostatectomy, androgen deprivation, local radiotherapy and chemotherapy. But there is still no effective treatment currently for the patients who failed in the primary treatments or who are diagnosed as advanced prostate cancer. Therefore, an improved and effective treatment is urgent. Gene therapy provided a novel approach for this.The RUNX(Runt-related transcription factor) family consists of three mumbers including RUNX1, RUNX2 and RUNX3. RUNX1 has been implicated in hematopoiesis,of which translocations in chromosome is frequent in aleukemic myelosis. RUNX2 is required for osteogenesis and is usually found mutation in cleido cranial dysplasia.RUNX3 is localized on chromosomes 1p36.1 and 4 in human and mouse respectively.RUNX3 gene contains six exons and P1, P2 promoters. As a tumor-suppressive gene,RUNX3 encoded an α subunit of PEBP2/CBF that can induce cell growth suppression,angiogenesis and cell apoptosis through TGF-β singaling pathway. Therefore, RUNX3 dysfunction is associated with development of a majority of human cancers. In addition,RUNX3 goes together with neurogenesis of dorasl root ganglia and T-cell differentiation.Inactivation of RUNX3 occurs mainly by deletion of its hemizygosity or hypermethylation of Cp G island in the promoter region. Moreover, it also occurs when RUNX3 protein is mislocalized from the nucleus to the cytoplasm. When RUNX3-negative gastric cancer cell lines was treated with HDAC inhibitor, RUNX3 would be reactivated causing tumor growth inhibition and apoptosis induction. Enforced RUNX3 expression in gastric cancer cell lines could cause downregulation of cyclin D1 and upregulation of p27 and capases3/7/8, leading to tumor cell apotosis and growth/ metastasis inhibition. RUNX3 in combination with adriamycin promoted caspase-8 and inhibited Bcl-2 expression, thus suppressing HCC tumor growth in vivo and in vitro. RUNX3 gene hepermethylation was found in 32.4% of the patients with prostate cancer and 14.3% of those with prostatic intraepithelial neoplasia(PIN), but absent in benign tumor and normal prostatic tissue.These clues suggested that RUNX3 might be involved in multiple aspects in prostatic carcinogenesis.In this study, a replication-defective adenovirus vector containing complete cds of RUNX3 gene was constructed and the construct was transfected in PC-3 human prostate cancer cell line. Then expression and sub-cellular location of RUNX3 were detected in PC-3 cells. Furthermore, the effect of RUNX3 overexpression on proliferation, apoptosis,invasion and migration of PC-3 cells was checked in vitro. We hope to provide a foundation for further researches of gene therapy for prostate cancer.Objective: To determine the effect of transcription factor RUNX3 on proliferation,apoptosis, invasion and migration of PC-3 cells.Methods: A replication-defective adenovirus vector p Ad-RUNX3 was constructed and the vector was infected with PC-3 human prostate cancer cell lines; then RUNX3 protein expression was detected with Western blot and its subcellular location was analyzed with indirect immunofluorescence; using MTT and Clone plate forming assay to its growth inhibitory effect on PC-3 cells was observed; cell apoptosis was detected withAnnexin-V staining combined with flow cytometry; transwell chamber experiment was performed to confirm the inhibition on invasion and migration in vitro.Results: The recombinant vector p Ad-RUNX3 was identified by endonuclease restriction following PCR-sequencing to confirm its correction. After transfection for 36 h,RUNX3 expression was detected in PC-3 cells and was located in the nucleus. The growth of PC-3 and its colony formation were inhibited significantly(P < 0.05); cell cycle arrest of PC-3 cells was markedly induced and the apoptosis pathway of PC-3 cells was activated when the cells were infected with 25 multiplicity of infection(MOI) for 36 h(P< 0.05). The invasion and migration of PC-3 cells was inhibited distinctly by Ad-RUNX3(P < 0.05).Conclusion: Expression of RUNX3 was located in nucleus of PC-3 cells infected with p Ad-RUNX3. The p Ad-RUNX3 could significantly inhibit the growth, invasion and migration of PC-3 cells and induce cell apoptosis, suggested a tumor suppressive role of RUNX3 in prostate cancer. |
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