Abstract 3376: CD133 plays a critical role in epithelial-mesenchymal transition related to pancreatic cancer migration and invasion

Abstract

Abstract Objective: Pancreatic cancer is an exceptionally devastating and incurable disease due to early local invasion and distant metastasis. Accumulated evidence shows that certain cells within solid tumors may reactivate a latent embryonic progress, epithelial-mesenchymal transition (EMT), during cancer progression. Through EMT, pancreatic tumor epithelial cells can acquire mesenchymal traits which facilitate migration and invasion. Previously, we reported that CD133-expressing cancer stem-like cells play an important role in tumorigenesis and chemoresistance of pancreatic cancer. In the present study we investigate whether CD133 plays a role in EMT using highly migrated cells enriched by a migration assay system. Methods: Expression of EMT characteristic markers, E-cadherin and vimentin, was examined in pancreatic cancer cell line, Capan-1. Highly migratory cell line Capan1-M9 was established by migration and invasion assay confirmed. CD133 expression was detected by FACS, real-time RT-PCR and Western blot. EMT-related genes (slug, snail, E-cadherin, vimentin, occludin, desmoplakin) were examined by real-time RT-PCR and Western blot. shRNA-CD133-GFP was transfected into Capan1-M9 by lentivirus vector to knock down endogenous CD133. Results: Typical EMT, which showed suppressed E-cadherin and elevated vimentin levels, was observed in migrating Capan-1 cells. Using a migration transwell system, we specifically established that Capan1-M9 cells showed migratory and invasive abilities two- to three-fold, compared with parental cells. FACS analysis showed that CD133 was enriched by more than 90% in Capan1-M9 cells. Furthermore, the elevated mRNA and protein levels of CD133 were confirmed in Capan1-M9 by real-time RT-PCR and Western blot, respectively. Importantly, as demonstrated by real-time RT-PCR, slug and snail EMT-related transcription factors in Capan1-M9 were upregulated by seven- and two-fold, respectively, compared with parental cells. Simultaneously, levels of vimentin mRNA expression increased two-fold. By contrast, occludin and desmoplakin cell-cell junction molecules were suppressed to half their previous level. Finally, shRNA-CD133-GFP achieved 85% knockdown of endogenous CD133, which not only inhibited migration and invasion but also suppressed slug EMT-related transcription factor expression to less than 20%. Conclusions: Our results suggest that CD133 contributes to migration and invasion of pancreatic cancer cells through a process which might trigger EMT, especially via slug upregulation. By targeting CD133-induced EMT in pancreatic cancer, transition to an invasive phenotype leading to metastasis may be preventable. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3376. doi:10.1158/1538-7445.AM2011-3376