DNMT3A governs tyrosine kinase inhibitors responses through IAPs and in a cell senescence-dependent manner in non-small cell lung cancer.

Patients with non-small cell lung cancer (NSCLC) treated with tyrosine kinase inhibitors (TKIs) inevitably exhibit drug resistance, which diminishes therapeutic effects. Nonetheless, the molecular mechanisms of TKI resistance in NSCLC remain obscure. In this study, data from clinical and TCGA databases revealed an increase in DNMT3A expression, which was correlated with a poor prognosis. Using NSCLC organoid models, we observed that high DNMT3A levels reduced TKI susceptibility of NSCLC cells via upregulating inhibitor of apoptosis proteins (IAPs). Simultaneously, the DNMT3Ahigh subset, which escaped apoptosis, underwent an early senescent-like state in a CDKN1A-dependent manner. Furthermore, the cellular senescence induced by TKIs was observed to be reversible, whereas DNMT3Ahigh cells reacquired their proliferative characteristics in the absence of TKIs, resulting in subsequent tumour recurrence and growth. Notably, the blockade of DNMT3A/IAPs signals enhanced the efficacy of TKIs in DNMT3Ahigh tumour-bearing mice, which represented a promising strategy for the effective treatment of NSCLC.

Cyclooxygenase-2 mediates gefitinib resistance in non-small cell lung cancer through the EGFR/PI3K/AKT axis.

Gefitinib is a potent inhibitor of EGFR and represents the front-line treatment for non-small cell lung cancer (NSCLC) therapeutics. However, NSCLC patients are prone to develop acquired resistance through as yet, undefined mechanisms of resistance. Here, we investigated the role of COX-2 during gefitinib resistance in NSCLC cells and revealed its underlying mechanism(s) of action. We report the upregulation of COX-2 in gefitinib-resistant NSCLC tissues and cells, which is associated with poor prognosis. In vitro assays in NSCLC cells (PC9/GR) showed that COX-2 facilitates gefitinib resistance in NSCLC cells through its effects on P-gp, MRP1, and BCRP, and cancer cell migration and invasion. In vivo, COX-2 silencing could repress tumor growth. We found that the overexpression of COX-2 enhances the transcription of MMP-2, MMP-7, and MMP-9 which mediates PI3K-AKT activation. In summary, we demonstrate that COX-2 mediates the gefitinib resistance of NSCLC cells through its interaction with EGFR and the PI3K-AKT axis. This highlights COX-2 as a novel molecular target for NSCLC.

SPOP promotes SIRT2 degradation and suppresses non-small cell lung cancer cell growth.

SIRT2 is a NAD-dependent deacetylase and inhibition of SIRT2 has a broad anticancer activity. Here we report that SPOP binds to SIRT2 and mediates its degradation by the 26S proteasome, which can be blocked by MG132 treatment. We also found that the levels of SPOP significantly decreased, while the levels of SIRT2 significantly increased in non-small cell lung cancer (NSCLC) cell lines, compared to normal bronchial epithelial cell line and NSCLC specimens, compared to the paired non-tumor lung tissue. Furthermore, SPOP can suppress NSCLC cell growth. Notably, mutations in NSCLC inhibit the abilities of SPOP to degrade SIRT2 and suppress NSCLC cell growth. These results reveal a novel regulation of SIRT2 by SPOP mediated degradation, which is important for the growth of lung tumor cells.

Overexpression of miR-100 inhibits cancer growth, migration, and chemosensitivity in human NSCLC cells through fibroblast growth factor receptor 3.

Nonsmall cell lung cancer (NSCLC) is a commonly occurring lung cancer. A combination of molecular biological treatments with regular chemotherapy may result in improved therapeutic outcome. Here, we reported significantly higher levels of fibroblast growth factor receptor 3 (FGFR3) and significantly lower levels of miR-100 in the NSCLC specimen, compared to the paired NSCLC-adjacent normal lung tissues. Moreover, the levels of FGFR3 and miR-100 were inversely correlated. Bioinformatics analyses followed by luciferase reporter assay showed that miR-100 bound to the 3'-UTR of FGFR3 messenger RNA (mRNA) to inhibit its translation. Overexpression of miR-100 in NSCLC cells decreased FGFR3 protein levels, whereas inhibition of miR-100 increased FGFR3 protein levels, without affecting FGFR3 mRNA levels. Furthermore, overexpression of miR-100 suppressed cancer growth, migration, and chemosensitivity in NSCLC cells, while inhibition of miR-100 significantly facilitated them. Taken together, our data demonstrate that miR-100 may inhibit NSCLC through FGFR3.

Epithelial-to-mesenchymal transition markers to predict response of Berberine in suppressing lung cancer invasion and metastasis.

BACKGROUND: The effects of berberine on the metastatic potential of lung cancer cells and its underlying mechanisms have not been fully elucidated. Since epithelial-to-mesenchymal transition is a cellular process associated with cancer invasion and metastasis, we attempted to investigate the potential use of berberine as an inhibitor of TGF-ß1-induced epithelial-to-mesenchymal in A549 cells. METHODS: In this study, we investigated the anticancer activity of berberine against A549 cells in vitro and in vivo. BBR-induced apoptosis of the human lung cancer cells was determined by flow cytometry. The ability of BBR to inhibit TGF-ß-induced EMT was examined by QRT-PCR and Western blotting. The impact of BBR on A549 cell migration and invasion was evaluated by transwell assay. RESULTS: We demonstrated that TGF-ß1 induced epithelial-to-mesenchymal to promote lung cancer invasion and metastasis. Berberine inhibited invasion and migration of A549 cells, increased expression of the epithelial phenotype marker E-cadherin, repressed the expression of the mesenchymal phenotype marker Vimentin, as well as decreased the level of epithelial-to-mesenchymal -inducing transcription factors Snail1 and Slug during the initiation of TGF-ß1-induced epithelial-to-mesenchymal. Furthermore, berberine inhibited growth of lung cancer cells in vivo xenograft. CONCLUSIONS: Our findings provided new evidence that berberine is an effective inhibitor of the metastatic potential of A549 cells through suppression of TGF-ß1-induced epithelial-to-mesenchymal.