Adenovirus Delivered Tissue Inhibitor Of Metalloproteinases-3 Sensitizes HPV Positive Cervical Cancer Cells To Irradiation In Vitro And Vivo

The background and objective:Excessive degradation and remodeling of the extracellular matrix (ECM) is one of the hallmarks of cancer progression at nearly every step from the first breakdown of the basal membrane of a primary tumor up to the extended growth of established metastases. Matrix metalloproteinases (MMPs) is the most important proteases in ECM turn over, and many tumors have high levels of MMPs.The activities of MMPs can be inhibited by tissue inhibitors of metalloproteinases (TIMPs), which are the endogenous and specific inhibitors of MMPs. As a new member of the TIMPs family, TIMP-3 has several unique properties that set it apart from other TIMPs, including its ability to induce apoptosis and inhibit angiogenesis in many tumors.Cervical cancer is the second most common malignancy in women worldwide. The past study by the doctor zhangying in our lab has suggested that Ad-TIMP-3 is an efficient agent for cervical cancer treating. Transfered Ad-TIMP-3 could induce massive apoptosis of cervical cancer cells and it had marked bystand effect. Ad-TIMP-3 remarkably arrested CaSKi cell in G2/M phase prior to apoptotic cell death. Combined Ad-TIMP-3 and radiation could induce stronger cytotoxic effect. In summary, there is additive or synergistic effect when using Ad-TIMP-3 and radiotherapy in combination. In vivo, directed injection of Ad-TIMP-3 into CaSKi tumors subcutaneously implanted into nude mice only, or followed by intraperitoneal administration of cisplatin, both could inhibit tumor growth significantly.In the base of the study above,our study focuses on the aspect of whether exogenous TIMP-3 sensitizes HPV positive cervical cancer cells to irradiation. Methods:We measured the expression of TIMP-3 mRNA by RT-PCR and TIMP-3 protein by Western Blot in CaSKi and HeLa-Luc before and after transfered Ad-TIMP-3.An adenovirus expressing TIMP-3 (Ad-TIMP-3), alone or in combination with irradiation, was used to treat HPV positive cervical cancer cells HeLa-Luc and CaSki, we compared the growth inhibition efficacy,invasion and adhesion ability. In vivo, we injected different HeLa-Luc cells treated by Ad-TIMP-3, x-ray, combination of this two or none of these subcutaneously into nude mice, and measured the growth of the tumor.Results:RT-PCR and Western Blot revealed that the expression of exogenous TIMP-3 was elevated obviously after infection. Ad-TIMP-3 suppressed the growth of HPV positive cervical cancer cells. Combination of Ad-TIMP-3 and irradiation significantly suppressed the cell growth, and decreased the invasion and adhesion ability than separate treatment. In vivo, after being treated by combination of Ad-TIMP-3 and x-ray, the cervical cancer cells growing to tumors was inhibited significantly than other cells in nude mice.Conclusions:Therefore our findings suggestes that Ad-TIMP-3 is an efficient agent for cervical cancer treating. Ad-TIMP-3 sensitizes HPV positive cervical cancer cells to irradiation.Combination of Ad-TIMP-3 and x-ray is a potential novel approach to the therapy of HPV positive cervical cancer.