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Background: Hepatocellular carcinoma (HCC) is one of the most common types of malignant tumour and has poor prognosis. Currently, systematic chemotherapy is the only approach to prolong survival. Thus the development of new treatment regimens is urgently needed to improve the therapeutic efficacy. Our study intended to assess the combination of dasatinib and irinotecan against HCC and made an effort to develop a potential medical choice for advanced HCC patients.Methods: We used SRB colorimetric assay and clonogenic assay to assess antitumour effect in vitro and HCC xenograft model to assess antitumour effect in vivo. We applied flow cytometry and western blotting to explore the mechanism of the combined therapy. Knockdown and overexpression of PLK1 are also applied for validation.Results: We confirmed that dasatinib has synergistic effect with irinotecan (or SN38) on HCC both in vitro and in vivo. The effect is due to arisen apoptosis rate of HCC cells that is accompanied by mitochondria dysfunction. The enhanced antitumour efficacy of SN38 could be explained by additional inhibition of PLK1, which is triggered by dasatinib. Unlike existed PLK1 inhibitors, dasatinib does not inhibit PLK1 activity in a direct way. Instead, we found that dasatinib reduces PLK1 level by interfering with its protein synthesis progress. We validated that this kind of downregulation of PLK1 level has a key role in the synergistic effect of the two agents.Conclusions: Dasatinib is able to reinforce the anti-HCC efficacy of irinotecan/SN38 by downregulation of PLK1 synthesis. The combination of the two agents might be a potential medical choice for HCC therapy. [ABSTRACT FROM AUTHOR]

Two new platinum(II) complexes 7a and 7b with methyl hydrazinecarbodithioate derivatives of indolin-2-one have been prepared and characterized by single-crystal X-ray diffraction, NMR spectroscopy and mass spectrometry. Antiproliferative activity of the two complexes and their ligands 6a and 6b against HCT-116, MCF-7 and MDA-MB-231 cell lines was determined by the MTS assay. Complexes 7a and 7b exhibited stronger antiproliferative activity against three cell lines than compounds 6a and 6b (IC 50 , 1.89–5.60 versus 6.52–35.13 μM). Moreover, treatment of HCT-116 cells with the complexes resulted in an obvious sub-G1 peak by cell cycle profile analysis, and an increase of cleaved PARP1 and caspases 3, 7, and 9 by immunoblotting analysis. Live cell imaging showed that nucleus shrinkage and condensation started to appear when MCF-7 cells were treated with 7a for 8 h. Fluorescent spectrophotometric analysis revealed that the complexes physically associated with calf thymus DNA. Competitive DNA binding assays uncovered that the complexes non-covalently bind to DNA. Taken together, our results indicated that the two new platinum(II) complexes 7a and 7b non-covalently bind to DNA with high affinity and exhibit cytotoxicity against cancer cells by inducing apoptosis. [ABSTRACT FROM AUTHOR]

Background: Chemotherapy is the only therapy option for the majority of AML patients, however, there are several limitations for this treatment. Our aim was to find a new chemotherapy strategy that is more effective and less toxic. Methods: MTT assays and a xenograft mouse model were employed to evaluate the synergistic activity of all-trans retinoic acid (ATRA) combined with topotecan (TPT). Drug-induced DNA damage and apoptosis were determined by flow cytometry analysis with PI and DAPI staining, the comet assay and Western blots. Short hairpin RNA (shRNA) and a RARα plasmid were used to determine whether RARα expression influenced DNA damage and apoptosis. Results: We found that ATRA exhibited synergistic activity in combination with Topotecan in AML cells, and the enhanced apoptosis induced by Topotecan plus ATRA resulted from caspase pathway activation. Mechanistically, ATRA dramatically down regulated RARα protein levels and led to more DNA damage and ultimately resulted in the synergism of these two agents. In addition, the increased antitumor efficacy of Topotecan combined with ATRA was further validated in the HL60 xenograft mouse model. Conclusions: Our data demonstrated, for the first time, that the combination of TPT and ATRA showed potential benefits in AML, providing a novel insight into clinical treatment strategies. [ABSTRACT FROM AUTHOR]