The role of exportin 6 in cytoskeletal-mediated cell death and cell adhesion in human non-small-cell lung carcinoma cells following doxorubicin treatment

The actin cytoskeleton plays an important role in various cellular processes. The different forms ofactin (G-actin and F-actin) participate in the organization of nuclear structure and its functions. The structure of the actin cytoskeleton is controlled by proteins involved in the translocation of actin between cytoplasm and the nucleus. In this study, we used siRNA method to investigate the role of exportin 6 in the switching between nuclear and cytoplasmic F-actin pools in H1299 cells treated with no, 1.0 or 2.5 μM doxorubicin. We showed that silencing of exportin 6 expression changed the response of H1299 to doxorubicin. Here, we observed increased population of cells affected by doxorubicin-induced necrotic cell death. Furthermore, fluorescence studies showed that downregulation of exportin 6 exerted profound DOX-induced changes in the F-actin cytoskeleton architecture. The F-actin cytoskeleton was seen in the form of small fibers or aggregates after doxorubicin treatment. Additionally, some cells lost cell adhesion properties. Downregulation of exportin 6 influenced also transcriptional activity of the cells. In cells transfected with nontargeting siRNA, we observed a higher level of 5’-fluorouridine fluorescence than in cells with silenced export in 6 expression. In conclusion, we showed that downregulation of exportin 6 induced necrotic cell death. Moreover, the observed alterations of cell adhesion suggest the key role of cytoplasmic F-actin in maintaining intercellular junctional complexes and/or focal adhesion properties and the importance of the balance between nuclear and cytoplasmic F-actin pools

MOESM1 of Paclitaxel and the dietary flavonoid fisetin: a synergistic combination that induces mitotic catastrophe and autophagic cell death in A549 non-small cell lung cancer cells

Additional file 1: Figure S1. The combined effect of fisetin with mitoxantrone (MIT), or methotrexate (MTX), or arsenic trioxide (ATO). (a,b) Logarithmic combination index plot (Fa-log(CI) plot) for FIS and MIT or MTX, respectively. CI values (logarithmic) are plotted as a function of the fractional inhibition (fa) of cell viability/growth by computer simulation (CompuSyn software) from 0.1 to 0.95. In the Fa-log(CI) plot, the synergism is indicated by a negative value (log(CI) < 0), antagonism is indicated by a positive value (log(CI) > 0), and additive effect (denoted by a dashed line) is indicated by 0 (log(CI) = 0). (c) Combination index plot (Fa-CI plot) for FIS and ATO co-treatment. CI values are plotted as a function of the fractional inhibition (fa) of cell viability/growth by computer simulation (CompuSyn software) from 0.1 to 0.95. CI < 1 designates synergism, CI = 1 indicates additivity (denoted by a dashed line), and CI > 1 represents antagonism. In all cases triangles represent CI values derived from the actual experimental points