Role of the STAT3/survivin signaling pathway in the EML4-ALK-positive lung adenocarcinoma cell line H2228 before and after crizotinib-induced resistance

Objective This study investigated the role of the STAT3/survivin signaling pathway in the EML4-ALK- positive lung adenocarcinoma cell line H2228 before and after crizotinib-induced resistance. The mecha- nism of resistance was studied. Methods Cell viability was determined using the MTT assay. Crizotinib-induced apoptosis in H2228 and H2228 crizotinib-resistant cells treated with the indicated doses of crizotinib was measured at different times （24 h, 48 h, 72 h） using flow cytometry. The levels of p-ALK, ALK, p-STAT3, STAT3, and survivin after treatment of cells with 0, 0.3, and 1 pM crizotinib for 72 h were determined using Western blot analysis. DNA sequencing was used to identify mutations in H2228 crizotinib-resistant cells. Results The crizotinib IC50 values in H2228 and H2228 crizotinib-resistant cells at 72 h were 334.5 nM and 3418 nM, respectively. The resistance index of 1-12228 crizotinib-resistant cells was 10.20. Crizotinib induced apoptosis in H2228 cells and reduced the levels of p-ALK, p-STAT3, and survivin. In contrast, no changes in the levels of p-ALK, p-STAT3, and survivin were observed in H2228 crizotinib-resistant cells. The mutations 2067G--,A and 2182G--,C in EML4-ALK were present in the H2228 crizotinib-resistant cells. Conclusion Crizotinib decreased the viability of H2228 cells in a dose- and time-dependent manner. In the STAT3/survivin pathway, downregulation of p-ALK, p-STAT3, and survivin might contribute to crizo- tinib-induced apoptosis in H2228 ceils. However, the STAT3/survivin pathway in H2228 crizotinib-resistant cells was unaffected by crizotinib treatment. Acquired resistance in H2228 cells might be related to ALK mutations.

Molecular Mechanism of Induction on Apoptosis of Human Esophageal Cancer HCE-4 Cells by Active Components from Astragalus membranaceus

[Objectives] To investigate the pharmacologic effects of active components from A. membranaceus on human esophageal cancer HCE-4 cells and its apoptosis mechanism. [Methods] The viabilities of HCE-4 cells were measured by MTT assay. The induction of active components from A. membranaceus on apoptosis of HCE-4 cells was detected by Annexin V-FITC/PI double staining. The apoptotic-related protein expression levels were determined by Western blotting. [Results] Formononetin and astragaloside IV suppressed the proliferation of HCE-4 cells in a dose-dependent manner. The Annexin V-FITC/PI double staining results showed that formononetin and astragaloside IV could induce HCE-4 cells apoptosis in a time-dependent manner. The Western blotting results showed that formononetin and astragaloside IV could significantly down-regulate p-AKT,pro-caspase-3,and increase cle-caspase-3 protein expression in HCE-4 cells. [Conclusions]Active components from A. membranaceus such as formononetin and astragaloside IV significantly inhibited the proliferation of human esophageal cancer HCE-4 cells by inducing mitochondrial dependent apoptosis via AKT signaling pathway.

Cell signaling leads the way

Cells in plants, like in animals, constantly communicate with one another to coordinate their cellular activities in response to surrounding environmental conditions. Higher plants are multicellular organisms. A plant is originated from a single fertilized egg, which eventually develops into an intact individual with all necessary tissues and organs. Cell-to-cell communication is therefore especially critical throughout its life span, from embryo development, to tissue and organ formation, and finally to flowering and senescence, in addition.