Action Of TRAIL Gene On Human Colon Cancer Cell Line RKO Combined With DOX And A Case Report Of Cardiotoxicity Caused By DOX

Colorectal cancer is one of the most common malignant tumor in our country. The morbidity and mortality of colorectal cancer are increasing. Although the diagnosis and therapy technique have made large progress, the five years survive rate of coiorectal cancer still remain 50% to 65%. Comprehensive treatment model has been suggested on the management of colorectal cancer remedy, including operation, radiotherapy, chemotherapy, immunotherapy and gene therapy. The object is not only extend patients' life, but also to improve their life quality. Gene therapy is a complete new area in biotherapy.Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) is a new member of the TNF family, which can induce cells apoptosis through its special receptor. It is considered a safe agent for tumor therapy because of its selective cytotoxic effect. TRAIL appears to induce cyto-apoptosis in tumorigenic or transformed cells or virus infected cells but not in normal cells. But some trials show some kinds of tumor cell lines not so sensitivity to TRAIL. Some trials show it can increase TRAIL'S capability of inducing apoptosis when combined with some chemotherapy agents. So we observed the colon cancer cell line RKO's survival rate and apoptosis rate after transferring TRAIL gene combined with or without DOX's. Last, we report a case of cardiotoxity caused by low cumulated dose of DOX.Materials and methodsAdenoviral vectors: Ad/GT-TRAIL , Ad/GT-LacZ , Ad/GT-Bax and Ad/PGK-GV16. Human embryonal kidney cells transformed by introducing sheared fragments of Ad5 DNA, 293cell line, human colon cancer cell line RKO and drug doxorubicin. Human colon cancer cell line RKO was transfected with adenovirus-mediated TRAIL gene Ad/GT-TRAIL and combined with DOX. Cell growth and apoptosis were measured by MTT method and flow cytometry. RT-PCR exams whether there was any change of the TRAIL gene expression after combination with DOX.Results and discussion 1, All adenoviral vectors titer determined by optical absorbency at 260nm were5×1010partical/ml. 2, The cell line RKO was slightly suppressed by mediate adenovirus andsignificantly by TRAIL gene. These suppression percentages were 11.9%and50.1%. 3, DOX can not significantly enhanced suppression efficiency. Combined with DOX,the apoptosis of cell line RKO can be significantly enhanced by TRAIL gene, andthe apoptosis rate grows from 19.8% to 49.0%. 4, RT-PCR shows the expression of TRAIL gene was not enhanced when itcombined with DOX.Conclusion 1, TRAIL is able to suppress the growth of human colon cancer cell line RKO, andcan induces it apoptosis. 2, Combined with DOX, TRAIL's capability of apoptosis can be significantlyenhanced. 3, TRAIL's capability of apoptosis been enhanced comes out not by raising theexpression of TRAIL gene.