Analyzing Myc in cell transformation and evolution

K9(C4H4FN2O2)2Nd(PW11O39)2·25H2O induces apoptosis in human lung cancer A549 cells

Lung cancer is the leading cause of cancer-associated mortality worldwide. The present study investigated the effects of K₉(C₄H₄FN₂O₂)₂Nd(PW₁₁O₃₉)₂·25H₂O (FNdPW), a chemically synthesized polyoxometalate that contains rare earth elements, on lung cancer growth, and explored the mechanism underlying its actions. The effects of FNdPW on the cell viability and apoptosis of human lung cancer A549 cells were measured using MTT assay, acridine orange/ethidium bromide staining and electron microscopy. The expression of apoptosis-related proteins, including B-cell lymphoma (Bcl)-2-associated death promoter (Bad), phosphorylated (p)-Bad, X-linked inhibitor of apoptosis (XIAP), apoptosis-inducing factor (AIF), Bcl-2-associated X protein (Bax) and Bcl-2, was determined by western blotting. Caspase-3 activity was measured using a caspase-3 activity kit. After 72 h of incubation, FNdPW reduced cell viability and induced apoptosis in A549 cells in a concentration- and time-dependent manner. FNdPW upregulated the pro-apoptotic Bad and Bax proteins, and downregulated the anti-apoptotic p-Bad, Bcl-2 and XIAP proteins. Furthermore, FNdPW also enhanced caspase-3 activity and increased the protein level of AIF in A549 cells, which was independent of the caspase-3 pathway. These events were associated with the regulation exerted by FNdPW on multiple targets involved in A549 cell proliferation. Therefore, FNdPW may be a novel drug for the treatment of lung cancer.

Effects of suberoylanilide hydroxamic acid (SAHA) combined with paclitaxel (PTX) on paclitaxel-resistant ovarian cancer cells and insights into the underlying mechanisms

Background

Suberoylanilide hydroxamic acid (SAHA) is a member of the hydroxamic acid class of the newly developed histone deacetylase inhibitors. Recently, Suberoylanilide hydroxamic acid has attracted increasing attention because of its antitumor activity and synergistic effects in combination with a variety of traditional chemotherapeutic drugs. Paclitaxel (PTX), is a natural anticancer drugs; however, resistance to paclitaxel has become a major challenge to the efficacy of this agent. The purpose of this study was to investigate the effects of the combined application of these two drugs on the paclitaxel-resistant ovarian cancer OC3/P cell line.

Methods

In the present study, the effects of Suberoylanilide hydroxamic acid or/and paclitaxel on OC3/P cells cultured in vitro were analyzed in terms of cell viability, migration, cell-cycle progression and apoptosis by CCK-8, wound healing and flow cytometry assays. Changes in cell ultrastructure were observed by transmission electron microscopy. The expression of genes and proteins related to proliferation, apoptosis and drug resistance were analyzed by quantitative real-time polymerase chain reaction and Western blot analyses.

Results

There was no cross-resistance of the paclitaxel-resistant ovarian cancer OC3/P cells to Suberoylanilide hydroxamic acid. Suberoylanilide hydroxamic acid combined with paclitaxel significantly inhibited cell growth and reduced the migration of OC3/P cells compared with the effects of Suberoylanilide hydroxamic acid or paclitaxel alone. Q-PCR showed the combination of Suberoylanilide hydroxamic acid and paclitaxel reduced intracellular bcl-2 and c-myc gene expression and increased bax gene expression more distinctly than the application of SAHA or paclitaxel alone. Moreover, the level of mdr1 gene expression in cells treated with Suberoylanilide hydroxamic acid was lower than that of the control group (P <0.05). Western blot analysis showed that Suberoylanilide hydroxamic acid alone or in combination with paclitaxel enhanced caspase-3 protein expression and degraded ID1 protein expression in OC3/P cells.

Conclusion

Suberoylanilide hydroxamic acid inhibited the growth of paclitaxel-resistant ovarian cancer OC3/P cells and reduced migration by the induction of cell-cycle arrest, apoptosis and autophagy. These observations indicate the possible synergistic antitumor effects of sequential Suberoylanilide hydroxamic acid and paclitaxel treatment.