Evaluation of Cytotoxic and Anti-cancer Potential of Capsaicin on Lung Cancer Cell Line: An In Vitro Investigation

Background The leading cause of cancer-related deaths worldwide is lung cancer. Approximately 1.8 million new cases were diagnosed, and 1.6 million individuals died. Available treatment options are inefficient leading to tumour recurrence. Hence there is a need for novel therapeutic advancements in lung cancer treatment. Capsaicin, a naturally occurring protoalkaloid, was found to possess several potential benefits. Aim The aim of the study was to examine capsaicin's cytotoxic and anti-cancer effects in the lung cancer cell line (A549). Materials and methods The cell viability of lung cancer cells treated with capsaicin was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. A549 cells were treated with capsaicin at concentrations ranging from 25 to 150 µM/mL for 24 hours. Changes in cell morphology were observed using a phase-contrast microscope. Nuclear morphological alterations in the lung cancer cells were examined through acridine orange/ethidium bromide (AO/EtBr) staining and viewed under a fluorescent microscope to identify apoptotic nuclei. Gene expression analysis was performed using quantitative real-time PCR (Polymerase Chain Reaction) to evaluate the expression of apoptotic genes, transforming growth factor-beta (TGF-β), and suppressor of mothers against decapentaplegic 2 (SMAD2). Capsaicin's anti-migratory properties were assessed using a scratch wound healing assay. Result Our study demonstrated that treating lung cancer cells with capsaicin dramatically decreased their vitality, with a statistically significant difference (p<0.05) between the treatment and control groups. In lung cancer cells, we measured the inhibitory concentration (IC-50) at 101.2μM/ml. Following treatment, the number of cells decreased, and those that remained exhibited cytoplasmic membrane blebbing and shrunk. With AO/EtBr staining, treated cells showed an increased number of apoptotic cells. The study's findings showed that after receiving capsaicin, there was a significant downregulation of TGF-β and SMAD2. Moreover, when compared to control cells, capsaicin-treated cells' migration was markedly reduced. Through modification of the TGF-β/SMAD2 signaling system, capsaicin therapy dramatically promotes apoptosis and inhibits migration. Conclusion In conclusion, the study's results indicate that capsaicin may have anti-tumor effects on lung cancer cells. To fully comprehend the mechanism underlying capsaicin's anticancer potential and its therapeutic application, further studies are much needed.