Impact of miR-519d on the Biological Activity of Non-Small Cell Lung Cancer Cells and Its Mechanism.

Objective: This study aimed to investigate the impact of miR-519d on the biological activity of non-small cell lung cancer (NSCLC) cells and elucidate its underlying mechanism. Methods: An experimental study design was adopted, and a cell culture-based study was conducted. We obtained non-small cell lung cancer cell lines from the ATCC cell bank and categorized them into three groups: the miR group, the NSCLC group, and the Negative control group. Various methods, including flow cytometry, quantitative real-time polymerase chain reaction (qRT-PCR), Transwell assays, Western blotting, and the Cell Counting Kit-8 (CCK-8) assay, were employed to assess miR-519d expression, apoptosis, proliferation, migration, and nuclear factor-kappa B (NF-KB) p65 protein content, thus exploring the impact of miR-519d on the biological activity of NSCLC cells. Results: In the miR group, we observed the highest expression level of miR-519d in NSCLC cells. Furthermore, the miR group exhibited the greatest number of apoptotic cells and the highest apoptosis rate (P < .05). Notably, the Transwell assay revealed reduced migration of NSCLC cells in the miR group, while the NSCLC cells in the control group exhibited more migratory activity. The cell counts of NSCLC cells also significantly decreased in the miR group, with migration comparable to the Negative control group (P > .05). Western blot analysis indicated that NF-KB p65 protein expression was highest in the Negative control group but significantly reduced in the miR group (all P < .05). Conclusions: miR-519d is downregulated in NSCLC cells. Elevating the expression of miR-519d inhibits various biological activities of lung cancer cells, including migration and proliferation. The downregulation of NF-KB p65 likely mediates this inhibition.

GABA regulates the proliferation and apoptosis of head and neck squamous cell carcinoma cells by promoting the expression of CCND2 and BCL2L1.

Gamma-aminobutyric acid (GABA) is a multifunctional molecule that is widely present in the nervous system and nonneuronal tissues. It plays pivotal roles in neurotransmission, regulation of secretion, cell differentiation, proliferation, and tumorigenesis. However, the exact mechanisms of GABA in head and neck squamous cell carcinomas (HNSCCs) are unknown. We took advantage of RNA sequencing in this work and uncovered the potential gene expression profiles of the GABA-treated HNSCC cell line HN4-2. We found that the expression of CCND2 and BCL2L1 was significantly upregulated. Furthermore, GABA treatment inhibited the cell apoptosis induced by cisplatin and regulated the cell cycle after treatment with cisplatin in HN4-2 cells. Moreover, we also found that GABA could upregulate the expression of CCND2 and BCL2L1 after treatment with cisplatin. Our results not only reveal the potential pro-tumorigenic effect of GABA on HNSCCs but also provide a novel therapeutic target for HNSCC treatment.

EGFR TKIs impair lysosome-dependent degradation of SQSTM1 to compromise the effectiveness in lung cancer.

Tyrosine kinase inhibitors for epidermal growth factor receptor (EGFR TKIs) greatly improved clinical outcomes of patients with non-small cell lung cancer (NSCLC). Unfortunately, primary and acquired resistance limits their clinical benefits. To overcome such resistance, new generations of EGFR TKIs have been developed by targeting newly identified mutations in EGFR. However, much less effort has been put into alternative strategies, such as targeting the intrinsic protective responses to EGFR TKIs. In this study, we found that EGFR TKIs, including gefitinib and AZD9291, impaired lysosome-dependent degradation of SQSTM1, thus compromising their anti-cancer efficiency. By accumulating in the lysosome lumen, gefitinib and AZD9291 attenuated lysosomal acidification and impaired autolysosomal degradation of SQSTM1 owing to their intrinsic alkalinity. As a result, SQSTM1 protein was stabilized in response to gefitinib and AZD9291 treatment and conferred EGFR TKI resistance. Depleting SQSTM1 significantly increased the sensitivity of NSCLC cells to gefitinib and AZD9291 both in vitro and in vivo. Furthermore, a chemically modified gefitinib analog lacking alkalinity displayed stronger inhibitory effects on NSCLC cells. Therefore, targeting accumulated SQSTM1 or chemically modified EGFR TKIs may represent new strategies to increase the effectiveness of EGFR targeted therapy.