Intracellular uptake of an antitumor-active azole-bridged dinuclear platinum(II) complex in cisplatin-resistant tumor cells

Cisplatin in Liver Cancer Therapy

Hepatocellular carcinoma (HCC) is the most common primary liver tumor and is often diagnosed at an unresectable advanced stage. Systemic chemotherapy as well as transarterial chemoembolization (TACE) and hepatic arterial infusion chemotherapy (HAIC) are used to treat advanced HCC. TACE and HAIC have long been the standard of care for patients with unresectable HCC but are limited to the treatment of intrahepatic lesions. Systemic chemotherapy with doxorubicin or chemohormonal therapy with tamoxifen have also been considered, but neither has demonstrated survival benefits. In the treatment of unresectable advanced HCC, cisplatin is administered transhepatic arterially for local treatment. Subsequently, for cisplatin-refractory cases due to drug resistance, a shift to systemic therapy with a different mechanism of action is expected to produce new antitumor effects. Cisplatin is also used for the treatment of liver tumors other than HCC. This review summarizes the action and resistance mechanism of cisplatin and describes the treatment of the major hepatobiliary cancers for which cisplatin is used as an anticancer agent, with a focus on HCC.

Pharmacodynamic Modeling to Evaluate the Impact of Cimetidine, an OCT2 Inhibitor, on the Anticancer Effects of Cisplatin

Despite potent anticancer activity, the clinical utilization of cisplatin is limited due to nephrotoxicity. As Organic Cation Transporter 2 (OCT2) has been shown to be one of the key transporters involved in the uptake of cisplatin into renal proximal tubules, OCT2 inhibitors such as cimetidine have been explored to suppress cisplatin-induced nephrotoxicity. Nonetheless, the impact of OCT2 inhibition or cimetidine on the anti-cancer effects of cisplatin has not been extensively examined. The main objective of the present study was to quantitatively characterize the anticancer effects of cisplatin and cimetidine and determine their nature of interactions in two cancer cell lines, OCT2-negative hepatocellular carcinoma (HCC) cell line, Huh7, and OCT2-positive breast cancer cell line, MDA-MB-468. First, we determined the static concentration-response curves of cisplatin and cimetidine as single agents. Next, with the help of three-dimensional (3D) response surface analyses and a competitive interaction model, we determined their nature of interactions at static concentrations to be modestly synergistic or additive in Huh7 and antagonistic in MDA-MB-468. These results were consistent with the cell-level pharmacodynamic (PD) modeling analysis which leveraged the time-course effects of drugs as single agents and drug combinations. Our developed PD model can be further used to design future preclinical studies to further investigate the cisplatin and cimetidine combinations in different in vitro and in vivo cancer models.

The effect of R547, a cyclin-dependent kinase inhibitor, on hepatocellular carcinoma cell death

Hepatocellular carcinoma (HCC) is the third main cause of cancer-related death. Cyclin-dependent kinases (CDKs) and their cyclin partners regulate the cell cycle. Since inhibition of CDKs gives some guiding ideas for cancer studies, we aimed to determine the possible effects of R547, a cyclin kinase 1-2-4 inhibitor, on proliferation and apoptotic mechanisms of Hep G2 cells (human) and H-4-II-E cells derived from rat HCC. We determined in vitro survival rates with MTT assay, apoptosis with flow cytometry, morphological changes with confocal microscopy, and ultrastructural changes by transmission electron microscopy. Cisplatin was used as a positive control. After 24 h of culture with 0.1, 1, 10, 50, and 100 µM doses of R547, the corresponding percentages of live Hep G2 cells were 101%, 94%, 93%, 89%, and 79% (P < 0.001), respectively. However, with the same R547 doses the live Hep G2 cell percentages were 92%, 101%, 53.6% (P <0 .01), 47.4% (P < 0.001), and 41% (P < 0.001), respectively, after 48 h. After 24 h of incubation with the same doses of R547, the survival percentages of live rat cells were 90%, 80% (P < 0.01), 63% (P < 0.001), 47% (P < 0.001), and 43% (P < 0.001), respectively. The percentages of surviving H-4-II-E cells were 96%, 85% (P < 0.01), 46% (P < 0.001), 44% (P < 0.001), and 45% (P < 0.01), respectively, after 48 h. Since R547 did not significantly affect Hep G2 cell survival in 24 h, experiments of apoptosis were carried out with H-4-II-E cells. The early apoptotic rates of 38% and 45% (P < 0.05 for both) after applications of 10 and 25 μM R547 (control: 4.1%), respectively, indicated that R547 has an apoptotic effect on H-4-II-E cells in 24 h. The apoptosis morphology at 24 h of treatment was clearly observed with microscopic examinations. According to our results, it is obvious that R547 has antiproliferative action when compared to cisplatin.

Antitumor Activity of Cyclodextrin-based Supramolecular Platinum Prodrug In vitro and In vivo

Background:

Considering the limitations of cisplatin in clinical application, there is ongoing research to fabricate new platinum-containing prodrug which are highly effective to tumor cells and have low toxicity to normal cells.

Methods:

In this study, a cyclodextrin-based supramolecular platinum prodrug that is 6,6’-ophenylenediseleno- bridged bis (β-cyclodextrin)s (CD) and its potassium tetrachloroplatinate(II) complex was reported. The cytotoxicity experiments were performed to evaluate the anticancer activities of supramolecular prodrug in vitro by means of MTT assay. The practical application of supramolecular prodrug in tumor treatment in vivo were evaluated using BALB/c nude mice model bearing Hela cancer cells.

Results:

Compared with commercial anticancer drug cisplatin, the resultant cyclodextrin-based platinum prodrug exhibited comparative anticancer effect but with much lower toxicity side effects in vitro and in vivo.

Conclusion:

The cyclodextrin-based supramolecular platinum prodrug displayed antitumor activity comparable to the commercial antitumor drug cisplatin but with lower side effects both in vitro and in vivo, implying that the two adjacent cyclodextrin cavities not merely act as desired solubilizer, but also endowed the prodrug with cell permeability through the interaction of cyclodextrin with phospholipids and cholesterol on cell membrane.