Methylation of hypoxia-inducible factor 3 subunit alpha contributes to poor prognosis in lung adenocarcinoma.

Hypoxia-inducible factor 3 subunit alpha (HIF3A) has been implicated in various types of cancers, while its precise role in the lung adenocarcinoma remains unclear. Our study aimed to investigate the roles of HIF3A in lung adenocarcinoma and its regulation by DNA methylation. We utilized bioinformatic tools, including UALCAN and KMPlot, to analyze the relationship between HIF3A expression, DNA methylation, and patient survival rate in lung adenocarcinoma. We also used siRNA-mediated knockdown of HIF3A and DNA-methyltransferase 1 (DNMT1), as well as the treatment of DNA methylation inhibitor 5-Azacytidine, in A549 and H1299 lung adenocarcinoma cell lines. qPCR, MTT, and cell counting assays were performed to evaluate the mRNA expression and cell viability. The bioinformatic analysis revealed that HIF3A expression was downregulated and its methylation was upregulated in lung tumor tissues. Additionally, Kaplan-Meier analysis indicated a correlation between low HIF3A expression and patient poor survival rate. We found that DNMT1 regulated HIF3A methylation. Knockdown of HIF3A promoted cancer cell proliferation. These data suggest that downregulation of HIF3A promotes tumor cell proliferation, and support that HIF3A methylation may serve as a prognostic factor for lung adenocarcinoma.

Hypoxia-induced antizyme inhibitors 2 regulates cisplatin resistance through epithelia-mesenchymal transition pathway in non-small cell lung cancer.

Antizyme inhibitors 2 (AZIN2) was found to be associated with poor prognosis of patients with rectal cancer. However, no studies have reported whether AZIN2 functions in non-small cell lung cancer (NSCLC). This study aimed to investigate the role of AZIN2 in cisplatin (DDP) resistance in NSCLC. We established DDP resistant A549 and H1299 cell lines. The transcriptional and translational expression levels were examined using quantitative real-time polymerase chain reaction and western blot. Cell apoptosis was evaluated by caspase-3 activity and nucleosome ELISA assays. Luciferase reporter assay was employed to evaluate the impact of hypoxia-inducible factor (HIF-1α) on AZIN2 transcription. AZIN2 expression was found to be associated with DDP resistance and poor prognosis in patients with NSCLC. AZIN2 overexpression promoted cell viability, colony formation, and reduced cell apoptosis in H1299 cells and A549 upon DDP treatment. Correspondingly, AZIN2 knockdown significantly inhibited cell viability and colony formation, and increased cell apoptosis upon DDP treatment. Interestingly, AZIN2 expression in NSCLC cells was significantly induced by hypoxia condition. The occupancy of HIF-1α, an important regulator of the hypoxia response, remarkably enriched at the promoter region of AZIN2 under hypoxia condition. In addition, AZIN2 overexpression resulted in epithelial-mesenchymal transition (EMT). The results suggested that hypoxia-induced AZIN2 high expression may contribute to DDP resistance development by promoting the EMT.

MiR-181a inhibits non-small cell lung cancer cell proliferation by targeting CDK1.

BACKGROUND: MicroRNAs (miRNAs) emerge as important regulators involved in malignant progression in some tumors. MiR-181a has been found to function as a tumor suppressor in some tumors including non-small cell lung cancer (NSCLC). However, the functional role of miR-181a in NSCLC still needed to be investigated. METHODS: The expression of miR-181a were determined by qRT-PCR, the association between miR-181a and clinicopathological data were performed by chi-square test and survival analysis were evaluated by Kaplan-Meier curve and log rank test. Cell proliferation and invasion were assessed by CCK8, cell colony formation and transwell assays. Luciferase reporter assay demonstrated that CDK1 was a target of miR-181a. Western blot assay detected the relative protein expression. RESULTS: In the study, our results showed that miR-181a was significantly down-regulated in non-small cell lung cancer (NSCLC) tissues and cell lines. MiR-181 expression levels were significantly associated with histological grade, N status and TNM stage in the patients and lower miR-181a predicted a poor prognosis in NSCLC patients. Furthermore, upregulation of miR-181a significantly suppressed the NSCLC cell proliferation, colony formation, and cell invasion capacities. Moreover, upregulation of miR-181a inhibited CyclinB1 and CyclinD1 expression in NSCLC cells. Luciferase activity assay results demonstrated CDK1 was a direct target of miR-181a and miR-181a inhibited cell proliferation by regulating the mRNA and protein levels of CDK1 in NSCLC cells. CONCLUSION: These data suggested that miR-181a plays a tumor suppressor and may be a potential therapeutic target for NSCLC patients.