Study Of ATRA Enhancing The Bystander Effect Of HSV-TK/GCV Gene System On Prostate Cancer

Object of the experiment:1,We are going to study the expression of Cx43 Prostate cancer and its biological meaning.2,To observe if ATRA can enhance the bystander effect of HSV-TK/GCV on PC-3 cells in vitro. And discuss whether the mechanism is associated to the role of improving the expression of Cx43 and the function of GJIC. We offered the theory evidence of combining using ATRA and HSV-TK/GCV gene system.The methods and the results:1,We evaluated the expression of Cx43 by immunohistochemistry in 15 normal prostate tissues, 35 prostate cancer tissues and the PC-3 cell line . The expression of Cx43 was intensive in normal prostate tissues. It was clearly located on the plasma membrane, but faint or negative in 74.2% of the cancer tissues. The expression of Cx43 was reduced in early highly differentiated prostate cancers, and was negative to the malignant type. The expression of Cx43 was reduced in PC-3 cells. At the same time, the mRNA of 6 fresh normal prostate tissues and 6 fresh prostate cancers were evaluated by semi-quantity–RT -PCR, we fount that the Cx43mRNA was decreased in tumors(p<0.05 ).2,We evaluated the sensitivity of PC-3 cells to the HSV-TK/GCV after ATRA therapy, and evaluated whether ATRA can enhance the bystander effect of HSV-TK gene.The PC-3-TK+cells and the PC-3-TK- cells were cocultivated by different rations in different groups,The ratio of PC-3-TK+cells was 0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0 respectively , MTT were used to evaluate the bystander effect after ATRA therapy. The BSE of Ad-TK/GCV on PC-3 cell was poor, but improved after combined with ATRA. There was cooperation effect between ATRA and BSE of Ad-TK/GCV. The BSE of Ad-TK/GCV on PC-3 cell could be improved by combining with ATRA by reducing 20% TK+ cell at cell inhibitiaon rations of 50%Conclusion:The expression of Cx43 is evidently decreased in prostate cancers, which may induce the reduced function of GJIC. We observed the sensitivity of PC-3 cells to the HSV- TK /GCV is increased after ATRA therapy, and the ATRA can enhance the bystander effect of HSV-TK gene. It is related to that the ATRA can improve the function of GJIC and increase the expression of Cx43.