The Renal Toxicity Of Platinum Anticancer Drugs In Vitro Comparative Study

The using of in vitro model to screen the lead candidates and compare the relative toxicity is the hot subject of the Discovery Toxicology. Nephrotoxicity is one of the main side effects of drugs. Within the kidney, the proximal tubular cells are exposed to the highest concentration of xenobiotics due to their transporting, concentrating, and drug metabolizing abilities. Therefore nephrotoxicity is best studied in these particular cells.The OK and LLC-PK1 cells are generally used, however, the OK cell can not express the marker enzyme of proximal tubular cells -AP and y -GT. LLC-PK1 cell lacks of the G-6-P and hexokinase and can not glyconeogenesis. The HK-2 cell is an established epithelial cell line derived from adult human kidney, which retains a phenotype indicative of well-differentiated proximal tubule epithelial cell .There are no reports on this cell using as a screen model. Cisplatin (CDDP) is an effective agent in the treatment of solid tumors, but renal dysfunction after cisplatin treatment is common, and acute renal failure may develop after exposure to a single dose. Carboplatin (CBDCA) is synthesized on the base of CDDP, which has the similar anticancer ability and less nephrotoxicity. Dicycloplatin (DCP) is the first platinum complex synthesized by our country. As DCP is still at the clinical stage, its toxic data still unknown. In the present study, a combination of techniques was used to compare the toxicity of the three platinum complexes using cultured human renal tubular epithelial cell (HK-2), and the speciality and sensitivity of the cell were also evaluated by in vivo and in vitro tests. This study not only paves the way for the establishment of the in vitro model to assess the nephrotoxicity of drugs, but also provides the reference for the clinical use of the DCP and the synthesis of platinum complex.In this study, we constructed a screening battery for the evaluation of the nephrotoxicity using a cultured human renal tubular epithelial cells(HK-2). The usefulness of the cell model is examined. Three known nephrotoxins, cisplatin, amphotericin B, cyclosporine A, and another three less nephrotoxic drugs, aspirin, amoxicillin, cyclophosphate, which are clinically known no adverse effects to kidney, were tested with the cell based assays. The results show that cisplatin, amphotericin B, and cyclosporine Acyclosporine A could cause statisitical toxicity to HK-2 cell at 10~50umol/L, but aspirin, amoxicillin, cyclophosphamide caused the same effects around 1mmol/L. For example, cisplatin caused the change of cell cycle and LDH leakage at 5umol/L, and aspirin could not cause the same effects even at lmmol/L. The results correlate well with the clinical toxicity, and the HK-2 cells derived from normal human appear to be specific for nephrotoxic agents. The cytotoxicity screen proves to be a useful tool for predicting potential nephrotoxicities associated with drug candidates under development. In order to compare the nephrotoxicity of the three platinum complexes, CDDP, CBDCA and DCP were assessed using the HK-2 cell at cellular and molecular level. The IC50, LDH leakage, the express of HSP70 and MT, the apoptosis and other toxicological endpoints were evaluated. At the same time, we also compared the nephrotoxicity of CDDP, CBDCA and DCP via the repetition of venous injection in rats, and the changes of the urine and blood samples and the pathological sections were analyzed. The in vivo results obtained are in agreement with in vitro findings in the HK-2 cells, that is, the nephrotoxicity of DCP is less than CDDP, and similar to CBDCA. At last, the apoptosis mechanisms of the three platinum complexes were also studied. CDDP, CBDCA, DCP can induced the HK-2 cell expressing the caspase8 and caspase 9. Both the inhibitores of caspase8 and caspase 9 can decrease the rates of the apoptosis.In this study, the in vitro nephrotoxicity of CDDP, CBDCA and DCP were evaluated by using theHK-2 cell. The possible nephrotoxic mechanisms of the platinum complexes induced in the HK-2 cell were also studi...