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Sorafenib displays a limited efficacy for advanced hepatocellular carcinoma ( HCC). Some patients with HCC initially respond to sorafenib, but eventually succumb to the disease, indicating that the acquired resistance to sorafenib reduces its beneficial effects. No alternative drugs are available after the failure of sorafenib therapy. Therefore, investigation of the mechanisms underlying the acquired resistance and development of second-line treatments for sorafenib-resistant HCC are urgently required. In this study, sorafenib-resistant HCC cells generated from sorafenib-sensitive human HCC cells were shown to overproduce hepatocyte growth factor ( HGF) and overexpress c-Met kinase and its phosphorylated form, leading to the activation of Akt and ERK (extracellular signaling-regulated kinase) pathways. Use of specific c-Met inhibitors enhanced the effects of sorafenib by inhibiting the growth of sorafenib-resistant HCC cells. Akt inhibitors, a class of second-line therapeutic drugs under investigation for treating HCC in clinical trials, enhanced the effects of sorafenib, but also activated the c-Met pathway in sorafenib-resistant cells. Dual inhibition of Akt and c-Met by their respective inhibitors, MK2206 and capmatinib, additively or synergistically suppressed sorafenib-resistant HCC cells in vitro and sorafenib-resistant HCC xenografts in mice. The anticancer activities of MK2206 mainly rely on its ability to induce cell apoptosis and autophagic death, while capmatinib treatment leads to cell cycle arrest at phase G1. These results provide strong evidence for further investigation on the clinical utility of dual inhibition of Akt and c-Met, particularly MK2206 and capmatinib, as a second-line therapy for advanced HCC that has acquired resistance to sorafenib. [ABSTRACT FROM AUTHOR]

This study investigated the contribution of survivin and its upstream regulators, AKT and hypoxia-inducible factor 1α ( HIF-1α), to the resistance of gastric cancer cells to cisplatin ( CDDP). We found that over-expression of survivin increased the resistance of SGC7901 and BGC823 gastric cancer cells to CDDP. Its over-expression abrogated CDDP-induced inhibition of cell proliferation and CDDP-induced cell apoptosis. In contrast, down-regulation of survivin expression using small hairpin RNA (sh RNA) vectors and the small-molecule inhibitor YM155, or inhibition of survivin function using a recombinant cell-permeable dominant-negative survivin protein (d NSur9), promoted CDDP-induced apoptosis. CDDP-resistant sub-lines generated from the parental SGC7901 and BGC823 cells by exposure to increasing concentrations of CDDP expressed higher levels of HIF-1α and survivin in response to hypoxia, and higher levels of phosphorylated AKT (p AKT). Specific inhibition of AKT reduced the expression of HIF-1α and survivin, whereas specific inhibition or depletion of HIF-1α reduced survivin expression but had no effect on the expression of phosphorylated AKT. The expression levels of survivin affected the therapeutic efficacy of CDDP in treating gastric tumors in mice. Specific inhibition of survivin, AKT and HIF-1α enhanced the sensitivity of CDDP-resistant cells to CDDP. Specific inhibition of survivin, AKT and HIF-1α synergized with CDDP to suppress the growth of gastric tumors that had been engineered to overexpress survivin. In summary, the results provide evidence that up-regulation of survivin by AKT and HIF-1α contributes to CDDP resistance, indicating that inhibition of these pathways may be a potential strategy for overcoming CDDP resistance in the treatment of gastric cancer. [ABSTRACT FROM AUTHOR]

Abstract: The present study aimed to investigate the anti-cancer effects of hydroxytyrosol (HT) in human hepatocellular carcinoma (HCC) cells. Our results show that HT could inhibit proliferation, induce G2/M cell cycle arrest and apoptosis in human HCC cells. Mechanically, we found that HT could suppress the activation of AKT and nuclear factor-kappa B (NF-κB) pathways. HT also significantly inhibited the tumor growth, angiogenesis and the activation of AKT and NF-κB pathways in an orthotopic model of human HCC in vivo. These data suggest that HT may be a promising candidate agent for the treatment of HCC. [Copyright &y& Elsevier]

Abstract: Hepatocellular carcinoma (HCC) is a highly lethal malignancy mostly because of de novo and acquired resistance to conventional chemotherapy. Constitutive activation of Akt and nuclear factor-κB (NF-κB) represent major cellular abnormalities associated with both the pathogenesis and therapeutic resistance of HCC. The aim of the present study was to determine whether genistein, a natural Akt/NF-κB inhibitor, could enhance the anti-HCC efficacy of ATO both in vitro and in vivo. Our results demonstrated that genistein not only potentiated the proliferation-inhibiting and apoptosis-inducing effect of ATO on human HCC cell lines in vitro, but also dramatically augmented its suppressive effect on both tumor growth and angiogenesis in nude mice. The mechanism is at least partially due to the suppressive effect of genistein both on the proper and ATO-induced Akt activation, and on the activity of NF-κB, and the latter correlated with the suppression of NF-κB regulated gene products, including cyclin D1, Bcl-xL, Bcl-2, c-myc, COX-2, and VEGF. These data suggest that the combination of ATO with genistein presents a promising therapeutic approach for the treatment of HCC. [ABSTRACT FROM AUTHOR]