Selective cytotoxicity of a novel platinum (II) coordination complex on human gastric cancer cell lines and normal kidney cells

We have synthesized novel platinum (II) coordination complex containing cis-1,2-diaminocyclohexane (DACH) as a carrier ligand and 1,2-bis(diphenylphosphino)ethane (DPPE) as leaving group. Furthermore, nitrate was added to improve the water-solubility. A new series of (Pt(cis-DACH)(DPPE)) cntdot 2NO3 (PC) was evaluated its antitumor activity on various MKN-45 human gastric adenocarcinoma cell-lines and normal primary cultured kidney cells. The new platinum complex demonstrated high efficacy in the cytotoxicity on MKN-45 cell-lines as well as adriamycin-resistant (MKN-45/ADR) and cisplatin-resistant (MKN-45/CDDP) cells. The cytotoxicities of PC were found quite less than those of cisplatin in rabbit proximal renal tubular cells, human renal cortical cells and human renal cortical tissues using MTT assay, (3H)-thymidine uptake and glucose consumption tests. Based on these results, this novel platinum (II) coordination complex, was considered as better a valuable lead for improving antitumor activities with low nephrotoxicities in the development of a new clinically available anticancer chemotherapeutic agents.

In vitro cytotoxicity of novel platinum(II) coordination complexes containing diaminocyclohexane and diphenylphosphines

We have synthesized new platinum(H) analogs containing 1,2-diaminocyclohexane (dach) as a carrier ligand, 1,3-bis(diphenylphosphino) propane (DPPP) /1,2-bis(diphenylphosphino)ethane (DPPE) as a leaving group and nitrates to improve solubility. In the present study, the cytotoxicity of (Pt(trans-l-dach)(DPPP))cntdot2NO3 (KHPC-001) and (Pt(trans-l-dach)(DPPE)) cntdot 2NO3 (KHPC-002) was evaluated and compared on various P-388 cancer cell lines and porcine kidney cell line (LLC-PK1). The new platinum complexes demonstrated high efficacy on P-388 mouse leukemia cell line as well as cisplatin-resistant (P-388/CDDP) and adriamycin-resistant (P-388/ADR) P-388 cell lines. The intracellular platinum content was measured by a flame atomic absorption spectrophotometer (FAAS), and it was comparable to the results of IC50 of the three complexes on LLC-PK1I and P-388/S cells, while only DPPE compound was accumulated in high volume in P-388/ADR and P-388/CDDP cells. While the DNA-interstrand cross-links of KHPC-001, KHPC-002 and cisplatin were similar on P-388/S leukemia cells, these new platinum complexes were much less DNA cross-linking to a kidney derived cell line, LLC-PK1. These results indicate that KHPC-001 and KHPC-002 are a third-generation platinum complexes with potent antitumor activity and low nephrotoxicity.