Activation of autophagy is a hallmark in tumor cells treated with chemotherapy, but the role of autophagy in acquired resistance of lung adenocarcinoma to cisplatin-based chemotherapy remains to be clarified. Our aim was to address that question by surveying the autophagic activity in parental lung adenocarcinoma cell line A549 and its 8-fold, more resistant subcell line, A549/DDP, which was obtained by treating cisplatin with increasing concentrations. A549/DDP and A549 cells were exposed to serum-free culture medium or ionizing radiation. To measure the stress-induced autophagy, LC3-II, as an autophagosome marker, was measured by immunofluorescence and Western blotting. To determine the effect of 3-MA, a known inhibitor of autophagy, on overcoming acquired cisplatin resistance, the MTT assay and flow cytometry were performed. Western blotting analysis demonstrated that LC3-II was increased in A549/DDP cells, compared with those of parental A549 cells, under stress conditions. Meanwhile, immunofluorescence staining showed that LC3-II protein was located mainly in the cytoplasm of A549/DDP. We also found that 3-MA can enhance the growth inhibition and apoptotic effect of cisplatin in acquired resistant cells (A549/DDP). Collectively, our results provide evidence that the upregulation of autophagy plays a major role in cisplatin resistance of A549/DDP cells.

Mesenchymal stem cells (MSCs) are generally used in regenerative medicine, tissue engineering and therapy for immune disorder diseases. However, due to the immunosuppressive function of MSCs, the application of MSCs in breast cancer therapy remains limited. Sirt1 is the closest mammalian homologue of the yeast enzyme Sir2 which has an established capacity to influence yeast replicative lifespan. In this study, we demonstrated the effect of MSCs with Sirt1 overexpression (MSCs-Sirt1) in mice bearing 4T1 breast cancer and investigated the underlying mechanism. Firstly, we found that MSCs could accelerate breast tumor growth with promoted proliferation and inhibited apoptosis, whereas MSCs-Sirt1 significantly suppressed tumor growth with proliferation inhibition and apoptosis promotion. Moreover, we detected that NK cells were the prominent antitumor effectors for the MSCs-Sirt1-induced antitumor activity. Besides that, CXCL10 and IFN-γ showed the high level expression in MSCs-Sirt1 treatment group. The impulsive effect of MSCs-Sirt1 on 4T1 cells in vivo could be reversed by inhibition of CXCL10 and IFN-γ. Overall, our results suggest that MSCs-Sirt1 can effectively inhibit breast tumor growth via the recruitment of NK cells in tumor inflammatory microenvironment.

Abstract. The aim of this study was to investigate the effect of fasudil on lung carcinoma-conditioned endothelial cells (LCc-ECs). To obtain LCc-ECs, human umbilical vein endothelial cells (HUVECs) were treated with conditioned cell culture media from human A549 lung adenocarcinoma cells. The effect of fasudil on the viability of LCc-ECs was assessed using the MTT assay, in vitro invasive ability was evaluated using the transwell chamber assay and cytoskeletal changes were detected using fluorescein-labelled phalloidin immunocytochemistry. RhoA mRNA and p-MLC protein expression were measured using RT-PCR and western blotting. Fasudil significantly and dose-dependently inhibited LCc-EC proliferation and in vitro invasive ability. Fasudil also led to stress fibre breakage and fracture in LCc-ECs, indicating that fasudil impacts polymerisation of the cytoskeletal actin filament network. Expression of RhoA mRNA and protein expression of the ROCK substrate p-MLC were reduced by fasudil, suggesting that fasudil can inhibit RhoA/ROCK signalling and attenuate angiogenesis in LCc-ECs. This study indicates that fasudil is an anti-angiogenic agent with potential application for the treatment of cancer, especially lung adenocarcinoma.