Although recent studies have reported different aspects of autophagy, from pro-survival to pro-death roles of this process in malignant cells, the underlying mechanisms by which autophagy inhibitors contribute toward the induction of programmed cell death in cancerous cells are still unclear. In the present study, we have attempted to explore some of the molecular features of pharmacological inhibition of autophagy in TF-1 cells (an acute erythroid leukemia model). Our findings indicated that ara-C induces autophagy (with alteration of LC3B, p62, and Beclin-1) in the cells; however, targeting autophagy by 3-methyladenine and chloroquine significantly increased caspase-dependent apoptosis and the sub-G1 compartment in ara-C-treated cells. Moreover, cell cycle analysis showed that 3-MA, as an early-stage autophagy inhibitor, could elevate the cell population in the G0/G1 cell cycle phase, which was associated with upregulation of p21 and p27 expressions. Interestingly, autophagy inhibition was also accompanied by downregulation of c-Myc gene and protein expression levels and upregulated levels of Bax and Bak gene expressions. In addition, following inhibition of autophagy, the levels of tumor-suppressive miRNA (i.e. miR-204) increased, whereas the values of oncogenic miRNAs (including miR-21, miR-221, miR-30a, and miR-17) decreased. Overall, our experiments indicate that autophagy inhibitors (especially chloroquine) seem to be promising agents for combination therapy in acute erythroid leukemia.

Purpose: Although the complex structure of acute lymphoblastic leukemia (ALL) and involvement of diverse pathways in its pathogenesis have put an obstacle in the way of efficient treatments, identification of strategies to manipulate the genome of neoplastic cells has made the treatment prospective more optimistic. Methods: To evaluate whether the transduction of Apoptin __a gene encoding a protein that participates in the induction of apoptosis__ could reduce the survival of leukemic cells, we generated recombinant lentivirus expressing Apoptin, and then, MTT assay, flow cytometric analysis of DNA content, western blotting, and qRT-PCR were applied. Results: Transduction of Apoptin into different leukemic cells was coupled with the reduction in the viability and proliferative capacity of the cells. Among all tested cell lines, Nalm-6 and C8166 were more sensitive to the anti-leukemic property of Apoptin. Moreover, we found that the transduction of Apoptin in the indicated cell lines not only induced G2/M cell cycle arrest but also induced apoptotic cell death by altering the balance between pro- and anti-apoptotic target genes. The efficacy of Apoptin transduction was not limited to these findings, as we reported for the first time that the overexpression of this gene could potentiate the anti-leukemic property of pan PI3K inhibitor BKM120. Conclusion: The results of this study showed that the transduction of Apoptin into lymphoblastic leukemia cell lines induced cytotoxic effects and enhanced therapeutic value of PI3K inhibition; however, further investigations are demanded to ascertain the safety and the efficacy of Apoptin transduction in patients with ALL.

Background: Gastric cancer (GC) is one of the most common malignancies worldwide. An in-depth understanding of the molecular mechanisms that underlies tumor GC will lead to breakthroughs in the targeted treatment of GC. Based on multiple lines of evidence, death-associated protein kinase 3 (DAPK3) regulates both programmed cell death including apoptosis and autophagy. The widespread experimental evidence raises the possibility of using DAPK-based gene therapy strategies. Objectives: The aim of this study was to investigate the effect of overexpression of DAPK3 using the PEGFPN1 vector on the gastric adenocarcinoma cell line (MKN45). Methods: The MKN45 cell lines were cultured in a DMEM culture medium and, then, the recombinant vector PEGFPN1-DAPK3 was transfected into the cells by lipofectamine 2000. The effects of the overexpression of the DAPK3 gene on MKN45 cells were evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), flow cytometry, and Real-time quantitative reverse transcription PCR (qRT-PCR) techniques. Results: Our findings indicated that overexpression of DAPK3 in MKN45 cells not only affects the expression of apoptosis-related genes but also changes the expression of autophagy-related genes. Additionally, overexpression of DAPK3 reduces the metabolic activity of cells. Conclusions: The overexpression of the DAPK3 gene can lead to cell death by both inducing apoptosis and autophagy pathways in the gastric adenocarcinoma cell line (MKN45). This anti-cancer activity may describe a hopeful strategy in the application of novel gene therapy for the treatment of gastric adenocarcinoma; however, further research is required to examine the clinical effectiveness of this strategy in GC treatment.

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