Resveratrol inhibits pancreatic cancer stem cell characteristics in human and KrasG12D transgenic mice by inhibiting pluripotency maintaining factors and epithelial-mesenchymal transition.

Sharmila Shankar,Dara Nall,Daniel Meeker,Jay Sharma,Jenna Passarini,Rakesh K Srivastava,Su-Ni Tang,Lin Zhang

doi:10.1371/journal.pone.0016530

Abstract

BackgroundCancer stem cells (CSCs) can proliferate and self-renew extensively due to their ability to express anti-apoptotic and drug resistant proteins, thus sustaining tumor growth. Therefore, the strategy to eradicate CSCs might have significant clinical implications. The objectives of this study were to examine the molecular mechanisms by which resveratrol inhibits stem cell characteristics of pancreatic CSCs derived from human primary tumors and KrasG12D transgenic mice.Methodology/Principal FindingsHuman pancreatic CSCs (CD133+CD44+CD24+ESA+) are highly tumorigenic and form subcutaneous tumors in NOD/SCID mice. Human pancreatic CSCs expressing high levels of CD133, CD24, CD44, ESA, and aldehyde dehydrogenase also express significantly more Nanog, Oct-4, Notch1, MDR1 and ABCG2 than normal pancreatic tissues and primary pancreatic cancer cells. Similarly, CSCs from KrasG12D mice express significantly higher levels of Nanog and Oct-4 than pancreatic tissues from Pdx-Cre mice. Resveratrol inhibits the growth (size and weight) and development (PanIN lesions) of pancreatic cancer in KrasG12D mice. Resveratrol inhibits the self-renewal capacity of pancreatic CSCs derived from human primary tumors and KrasG12D mice. Resveratrol induces apoptosis by activating capase-3/7 and inhibiting the expression of Bcl-2 and XIAP in human CSCs. Resveratrol inhibits pluripotency maintaining factors (Nanog, Sox-2, c-Myc and Oct-4) and drug resistance gene ABCG2 in CSCs. Inhibition of Nanog by shRNA enhances the inhibitory effects of resveratrol on self-renewal capacity of CSCs. Finally, resveratrol inhibits CSC's migration and invasion and markers of epithelial-mesenchymal transition (Zeb-1, Slug and Snail).Conclusions/SignificanceThese data suggest that resveratrol inhibits pancreatic cancer stem cell characteristics in human and KrasG12D transgenic mice by inhibiting pluripotency maintaining factors and epithelial-mesenchymal transition. In conclusion, resveratrol can be used for the management of pancreatic cancer.

Highlights

Pancreatic cancer is the fourth leading cause of cancer death in the United States
The objectives of our study were to examine the molecular mechanisms by which resveratrol inhibits pancreatic Cancer stem cells (CSCs) characteristics in human and KrasG12D transgenic mouse model, and examine whether inhibition of Nanog enhances the ability of resveratrol to inhibit self-renewal capacity of human pancreatic CSCs
We examined the expression of stem cell markers (CD133+CD44+CD24+ESA+), pluripotency maintaining factors (Nanog), signaling molecule (Notch-1) and drug resistant genes (MDR1 and ABCG2) in human normal pancreas, primary pancreatic cancer cells, and CSCs by q-RT-PCR (Fig. 1I)

Summary

Introduction

It is expected that approximately 32,000 Americans will die from pancreatic cancer this year. With an overall 5-year survival rate of 3% [1], pancreatic cancer has one of the poorest prognoses among all cancers [2]. 20% of pancreatic cancer patients are eligible for surgical resection [3]. There are limited treatment options available for the patients with pancreatic cancer because chemo- and radio-therapies are largely ineffective, and metastatic disease frequently redevelops even after surgery. Cancer stem cells (CSCs) can proliferate and self-renew extensively due to their ability to express anti-apoptotic and drug resistant proteins, sustaining tumor growth. The objectives of this study were to examine the molecular mechanisms by which resveratrol inhibits stem cell characteristics of pancreatic CSCs derived from human primary tumors and KrasG12D transgenic mice

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