The Study Of Screening Of Ovarian Cancer Drug Resistance Associated Genes And Relationship Between Drug Resistance And Apoptosis

Tumor cells can develop not only resistance to the agent employed for treatment but also cross-resistance to a spectrum of structurally and functionally diverse agents that have not been used. This phenomenon, termed multidrug resistance, is the major obstacle to successful chemotherapeutic treatment of many kinds of cancer. Further, over the last few years there has been increasing evidence that expression of certain genes may affect the cellular response to an apoptotic stimulus that modulate the sensitivity of cells to anti-cancer drugs. As we know, modulation of genes may influence drug sensitivity or resistance. Therefore, to elucidate the molecular mechanisms of anti-cancer drugs induced apoptotic cell death might further understand the cause of the drug resistance.Methods: (1) MDR ovarian cancer cell subline OC3/Adr was induced by pulse treatment of the human parent cell line OC3 using a single dose Adriamycin. Then, the analysis expression of drug resistance molecular and resistance index used the techniques of MTT, FACS western blot and RT-PCR. (2) Screening the differenece ESTs in gene expression associated with Adr resistance was used by differential display studies on the cell line OC3 and on acquired Adr-resistant subline OC3/Adr. (3) OC3cells were transfected with the plasmid pLXSN-Bcl-2 carrieing the human Bcl-2 cDNA which was controlled by the SV40 promotor sequence. After that a number of stable clones resistant to geneticin G418 were developed. The Bcl-2 transfected clones of OC3/Bcl-2 were sudsequently tested for their response to Adr-induced cytotoxicity by the MTT assay.Conclusions: (1) OC3/Adr drug resistance cell lines showed hjgh resistance not only to Adr but also to other anti -cancer drugs. 0C3/ADR obtained multidrugresistance and MDR mechanisms involved in high expressing MDR1 MRP and Bcl-2 moleculars. (2) We obtained 18 differences ESTs on the OC3/Adr and OC3 from DD-PCR. Four of them were identified. Particularly, S2 sequences has been found to be increased in the resistance cell lines by RT-PCR and deposited in GenBank: Hylobates AF117656. (3) Bcl-2 may play an important role in resistance Adr inducing apoptosis in OC3 cells fins, (4) Raji cell lines have been found to resistant apoptosis that induced by Adr. Again, the Bcl-2 might play an important role during the process of the drug resistance in Raji cells.