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Saracatinib is an oral Src‐kinase inhibitor and has been studied in preclinical models and clinical trials of cancer therapy. GMI, a fungal immunomodulatory protein from Ganoderma microsporum, possesses antitumor capacity. The aim of this study is to evaluate the cytotoxic effect of combination treatment with saracatinib and GMI on parental and pemetrexed‐resistant lung cancer cells. Cotreatment with saracatinib and GMI induced synergistic and additive cytotoxic effect in A549 and A400 cells by annexin V/propidium iodide assay and combination index. Using western blot assay, saracatinib, and GMI combined treatment synergistically induced caspase‐7 activation in A549 cells. Different from A549 cells, saracatinib and GMI cotreatment markedly increased LC3B‐II in A400 cells. ATG5 silencing abolished the caspase‐7 activation and reduced cell death in A549 cells after cotreatment. This is the first study to provide a novel strategy of treating lung cancer with or without drug resistance via combination treatment with GMI and saracatinib. [ABSTRACT FROM AUTHOR]

Nickel compounds are associated with lung and skin cancer incidence increase and accumulation of nickel in the body contributes to carcinogenesis. Upregulation of certain integrins in the primary tumor is associated with cancer metastasis and poor prognosis. However, the molecular mechanisms of nickel‐induced cancer metastasis are still unclear. The purpose of the present study was to investigate the effects of nickel chloride (NiCl2) on the progression of cancer during metastasis. The results of showed that NiCl2 induces the expression of integrin β3 mRNA and protein in a dose‐ and time‐dependent manner. Inhibition of integrin αvβ3 activation by ITGB3 ligand mimetics and GR144053, as well as downregulation of ITGB3 by lentiviral shRNA gene silencing, diminished NiCl2‐induced secretion of vascular endothelial growth factor‐a (VEGF‐a). Furthermore, pretreatment with type I TGF‐β receptor inhibitor, SB525334, suppressed the expression of ITGB3 at cell surface and secretion of VEGF‐a in NiCl2‐treated cells. In conclusion, NiCl2 induces the expression of ITGB3 through TGF‐β signaling activation, followed by increasing VEGF‐a secretion, revealing a novel role for ITGB3 in nickel compound‐induced cancer metastasis and tumor angiogenesis. [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE Autophagic cell death is considered a self-destructive process that results from large amounts of autophagic flux. In our previous study, GMI, a recombinant fungal immunomodulatory protein cloned from Ganoderma microsporum, induced autophagic cell death in lung cancer cells. The aim of this study was to examine the role of autophagosome accumulation in GMI-mediated cell death. EXPERIMENTAL APPROACH Western blot analysis, flow cytometry and confocal microscopy were used to evaluate the effects of different treatments, including silencing of ATP6V0A1 by use of short hairpin RNAi, on GMI-mediated cell death, lung cancer cell viability and autophagosome accumulation in vitro. KEY RESULTS Lysosome inhibitors bafilomycin-A1 and chloroquine increased GMI-mediated autophagic cell death. GMI and bafilomycin-A1 co-treatment induced the accumulation of large amounts of autophagosomes, but did not significantly induce apoptosis. GMI elicited autophagy through the PKB (Akt)/mammalian target of rapamycin signalling pathway. Silencing of ATP6V0A1, one subunit of vesicular H+-ATPases (V-ATPases) that mediates lysosome acidification, spontaneously induced autophagosome accumulation, but did not affect lysosome acidity. GMI-mediated autophagosome accumulation and cytotoxicity was increased in shATP6V0A1 lung cancer cells. Furthermore, ATP6V0A1 silencing decreased autophagosome and lysosome fusion in GMI-treated CaLu-1/GFP-LC3 lung cancer cells. CONCLUSION AND IMPLICATIONS We demonstrated that autophagosome accumulation induces autophagic cell death in a GMI treatment model, and ATP6V0A1 plays an important role in mediating autophagosome-lysosome fusion. Our findings provide new insights into the mechanisms involved in the induction of autophagic cell death. [ABSTRACT FROM AUTHOR]