Exploring acenocoumarol and silodosin as allosteric EGFR inhibitors for the treatment of non-small cell lung cancer [version 1; peer review: awaiting peer review]

Background Non-small-cell lung cancer (NSCLC) is a highly morbid disease. Chemotherapy for NSCLC lacks specificity and efficacy mainly because of drug resistance. The current study aimed to explore computational tools to target allosteric epidermal growth factor receptor (EGFR) sites and screen for the top molecules in vitro and in vivo xenograft models. Methods Molecular docking, virtual screening, and molecular dynamic studies revealed that acenocoumarol and silodosin are the top two allosteric EGFR inhibitors. They were further tested for cytotoxicity, apoptosis, cell cycle, and gene expression by qPCR, western blotting, A549 cell xenograft anti-proliferative activity, and tumor regression efficacy analysis. Results Acenocoumarol and silodosin exhibited cytotoxicity in A549 and IMR-90 cells at concentrations below 50 and 80 μM, respectively. Acenocoumarol and silodosin induced S-phase and G2/M-phase arrest in A549 cells in the cell cycle analysis. Both drugs showed early apoptosis at their IC 50 doses (acenocoumarol 50 μM and silodosin 25 μM). KRAS (Kirsten rat sarcoma viral oncogene homolog) and ERK2 (extracellular signal-regulated kinase 2) gene regulation in A549 cells was confirmed using qPCR. KRAS and ERK2 activities were quantified by western blot analysis. In the xenograft study, tumor size, body weight, and organ weight were significantly attenuated by the test drugs compared with the standard cisplatin. Immunoblotting and western blot results of the A549-xenograft tissue indicated downregulation of KRAS and ERK2. Furthermore, the test drugs have upregulated caspase-3 gene expression. Conclusion The drugs acenocoumarol and silodosin downregulate KRAS and ERK2 both in cell line and in Xenograft model. KRAS and ERK2 are associated with EGFR inhibition. Hence, acenocoumarol and silodosin can be further explored for repurposing studies in human trials.