Piperlongumine in combination with EGFR tyrosine kinase inhibitors for the treatment of lung cancer cells.

Objectives: EGFR tyrosine kinase inhibitor (EGFR-TKI) therapies such as erlotinib and gefitinib are approved for the treatment of non-small cell lung cancer (NSCLC). However, the high incidence of acquired resistance to these EGFR-TKIs may preclude their effectiveness. Piperlongumine (PPL), an extract from the long pepper fruit (Piper longum), has been shown to possess anticancer properties. The purpose of the study was to investigate piperlongumine as an anticancer agent and to study a combination treatment approach with EGFR-TKIs against lung cancer cells.

Methods: Anticancer efficacy of PPL, erlotinib (ERL), gefitinib (GEF), and cisplatin (CIS) were investigated in H1299 and H1975 cell lines. Cells were treated with PPL, ERL, GEF, and CIS alone, and in combination, cell viability was determined after 72 h. The mechanism of PPL-induced cytotoxicity was investigated via reactive oxygen species (ROS) induction, and apoptosis induction using acridine orange/ethidium bromide staining and flow cytometry. The effect of treatment on EGFR-mediated oncogenic signaling was investigated by immunoblotting for mitogenic and apoptotic markers.

Results: PPL exhibited a potent cytotoxic effect in H1299 and H1975 cells compared to ERL, GEF, and CIS. Combination treatments of PPL with GEF and ERL showed significant reductions in cancer cells compared to control in both cell lines, which were associated with apoptotic induction, but without significant ROS induction. Compared to control, PPL with GEF significantly increased apoptotic cell death in H1975as confirmed with flow cytometry. Treatment with PPL alone and in combination induced anti-mitogenic and apoptotic responses at the molecular level.

Conclusion: PPL sensitized lung cancer cells to EGFR-TKI and induced potent cytotoxic effects at low concentrations.