Nimbolide inhibits pancreatic cancer growth and metastasis through ROS-mediated apoptosis and inhibition of epithelial-to-mesenchymal transition.

Ramadevi Subramani,Viviana Gonzalez,Sushmita Nandy,Joshua Medel,Rajkumar Lakshmanaswamy,Fernando Camacho,Elizabeth Gonzalez,Arunkumar Arumugam,Mahesh Narayan,Andrew Ortega,Alok Kumar Dwivedi,Sandrine Bonkoungou

doi:10.1038/srep19819

Abstract

The mortality and morbidity rates of pancreatic cancer are high because of its extremely invasive and metastatic nature. Its lack of symptoms, late diagnosis and chemo–resistance and the ineffective treatment modalities warrant the development of new chemo–therapeutic agents for pancreatic cancer. Agents from medicinal plants have demonstrated therapeutic benefits in various human cancers. Nimbolide, an active molecule isolated from Azadirachta indica, has been reported to exhibit several medicinal properties. This study assessed the anticancer properties of nimbolide against pancreatic cancer. Our data reveal that nimbolide induces excessive generation of reactive oxygen species (ROS), thereby regulating both apoptosis and autophagy in pancreatic cancer cells. Experiments with the autophagy inhibitors 3-methyladenine and chloroquine diphosphate salt and the apoptosis inhibitor z-VAD-fmk demonstrated that nimbolide-mediated ROS generation inhibited proliferation (through reduced PI3K/AKT/mTOR and ERK signaling) and metastasis (through decreased EMT, invasion, migration and colony forming abilities) via mitochondrial-mediated apoptotic cell death but not via autophagy. In vivo experiments also demonstrated that nimbolide was effective in inhibiting pancreatic cancer growth and metastasis. Overall, our data suggest that nimbolide can serve as a potential chemo–therapeutic agent for pancreatic cancer.

Highlights

HPAC, MIAPaCa-2, PANC-1, and hTERT HPNE cells were treated with different concentrations of nimbolide (1–50 μ M) for 24 h, and cell viability was assessed using the MTS assay (a,c,d,g)
Nimbolide significantly inhibited the viability of the pancreatic cancer cell lines (HPAC, MIAPaCa-2, and PANC-1) in a dose-dependent manner (Fig. 1a,c,e)
The cell viability data demonstrate that nimbolide induced more than 50% cell death at a concentration of 5 μ M in HPAC and PANC-1 cells and at 3 μ M in MIAPaCa-2 cells

Summary

Introduction

HPAC, MIAPaCa-2, PANC-1, and hTERT HPNE cells were treated with different concentrations of nimbolide (1–50 μ M) for 24 h, and cell viability was assessed using the MTS assay (a,c,d,g). Morphology comparison of control and cells treated with the respective IC50 concentration of nimbolide (5 μ M, 3 μ M, and 5 μ M for HPAC, MIAPaCa-2, PANC-1 cells, respectively) viewed under a light microscope at 10X magnification (b,d,f,h). Based on the levels of its generation, ROS can either have beneficial or adverse effects on cells[15,16]. Pancreatic cancer cells generate moderate levels of ROS to aid in their proliferation, migration, and metastasis. Our data demonstrates that nimbolide-induced excessive ROS generation is the main cause of inhibition of pancreatic cancer growth and metastasis. Nimbolide is a promising anticancer agent that is highly effective against pancreatic cancer

Methods

Results

Conclusion