Novel imidazo[1,2-a]pyridine derivatives induce apoptosis and cell cycle arrest in non-small cell lung cancer by activating NADPH oxidase mediated oxidative stress.

Aims: Imidazo[1,2-a]pyridine-based analogues have recently gained significant interest because of their wide spectrum of biological activities including anti-cancer potential, however the development of targeted therapeutic candidates against non-small cell lung cancer (NSCLC) is of utmost need due to its high prevalence and poor prognosis. Herein, we have aimed to synthesized novel imidazo [1,2-a] pyridine derivatives (IMPA) by coupling with 2-amino-4H-pyran to enhance bioactivity against NSCLC.

Main Methods: We have designed and synthesized a series of fifteen novel imidazo [1,2-a] pyridine derivatives through molecular hybridization and studied their anti-cancer activity against in-vitro lung adenocarcinoma and 3D multicellular lung tumor spheroids.

Key Findings: IMPA-2, IMPA-5, IMPA-6, IMPA-8, and IMPA-12 markedly induced cytotoxicity by notably increased NADPH oxidase (NOX) activity, which results in the induction of ROS-mediated apoptosis in A549 lung cancer cells. It caused impairment of mitochondrial membrane potential by increasing pro-apoptotic BAX, and BAK1 expressions, and decreasing anti-apoptotic BCL2 expression, along with the induction of caspase-9/3 activation, however, these attributes were compromised in presence of N-acetyl-L-cysteine (NAC), a free radical scavenger. Increased ROS production by IMPAs also promotes p53 mediated cell cycle arrest through the inactivation of p38MAPK. Reduction of tumor size in IMPAs-treated 3D multicellular lung tumor spheroids gave further validation.

Significance: Beside cytotoxicity, IMPAs also inhibit lung cancer cell invasion and migration, suggesting their applicability in metastatic lung cancer. Therefore, IMPA derivatives could be used as potential anti-cancer agents in treating non-small cell lung cancer.