Metformin impairs cisplatin resistance effects in A549 lung cancer cells through mTOR signaling and other metabolic pathways

Abstract

Lung cancer is the leading cause of cancer-associated death worldwide and exhibits intrinsic and acquired therapeutic resistance to cisplatin (CIS). The present study investigated the role of mTOR signaling and other signaling pathways after metformin (MET) treatment in control and cisplatin-resistant A549 cells, mapping pathways and possible targets involved in CIS sensitivity. MTT, flow cytometry, clonogenic assay, western blotting, proteomic analysis using the Stable Isotope Labeling by Amino acids in Cell culture (SILAC) approach and reverse transcription-quantitative PCR were performed. The results revealed that CIS treatment induced mTOR signaling pathway overactivation, and the mTOR status was restored by MET. MET and the mTOR inhibitor rapamycin (RAPA) decreased the viability in control and resistant cells, and decreased the cell size increase induced by CIS. In control cells, MET and RAPA decreased colony formation after 72 h and decreased IC 50 values, potentiating the effects of CIS. Proteomics analysis revealed important pathways regulated by MET, including transcription, RNA processing and IL-12-mediated signaling. In CIS-resistant cells, MET regulated the apoptotic process, oxidative stress and G 2 /M transition. Annexin 4 (ANXA4) and superoxide dismutase 2 (SOD2), involved in apoptosis and oxidative stress, respectively, were chosen to validate the SILAC analysis and may represent potential therapeutic targets for lung cancer treatment. In conclusion, the chemosensitizing and antiproliferative effects of MET were associated with mTOR signaling and with potential novel targets, such as ANXA4 and SOD2, in human lung cancer cells.

SLURP-1 Controls Growth and Migration of Lung Adenocarcinoma Cells, Forming a Complex With α7-nAChR and PDGFR/EGFR Heterodimer

“…The PI3K/AKT/mTOR pathway is known to regulate growth, migration, and drug resistance in A549 cells (Wang et al, 2020;Morelli et al, 2021), Recently we have proposed that rSLURP-1 regulates this pathway by increasing expression of PTEN, -the negative regulator of PI3K (Shulepko et al, 2020b). In line with this hypothesis, here we observed that SLURP-1 induces significant inhibition of mTOR (S2448) and PTEN (S380) phosphorylation (Figure 1), which corresponds to inactivation of mTOR and activation of PTEN (Scully et al, 2014).…”

Isothiocyanates (ITCs) 1-(Isothiocyanatomethyl)-4-phenylbenzene and 1-Isothiocyanato-3,5-bis(trifluoromethyl)benzene—Aldehyde Dehydrogenase (ALDH) Inhibitors, Decreases Cisplatin Tolerance and Migratory Ability of NSCLC

“…Currently, potential supplements to cisplatin-based chemotherapy are being sought [ 77 , 78 , 79 ]. One such candidate is Disulfiram (DSF), which is an aldehyde dehydrogenase (ADH) inhibitor that has been used as a first-line anti-alcoholism Drug The drug has been reported to cause cell-cycle arrest in the G2/M phase and enhance cisplatin sensitivity in NSCLC lines [ 80 ].…”

Metformin-induced chemosensitization to cisplatin depends on P53 status and is inhibited by Jarid1b overexpression in non-small cell lung cancer cells

“…AMPK activation can phosphorylate and translocate P53 to the mitochondria and this translocation can be inhibited by pifithrin-μ [ 23 , 37 ]. In a parallel study, metformin does not induce AMPK phosphorylation, using the same protocol used to generate the A549Res cells [ 38 ]. However, metformin treatment decreases mTOR activity in both A549 and A549Res cells, as expected.…”

“…In a parallel study [ 38 ], applying a proteomic approach to analyze the very same cell population groups studied here, A549Res cells showed that metformin decreased the expression of Lactate Dehydrogenase B (LDHB) and Succinate-CoA Ligase GDP-Forming Subunit Beta (SUCLG2), which can convert lactate into pyruvate and catalyze the conversion of succinyl-CoA to succinate, respectively [ 41 , 42 ], on A549 cells. Nevertheless, metformin was not able to increase the lactate production in this population.…”