Polybromo 1/vimentin axis dictates tumor grade, epithelial-mesenchymal transition, and metastasis in pancreatic cancer
Munenori Kawai, Akihisa Fukuda, Munehiro Ikeda, Kei Iimori, Kenta Mizukoshi, Kosuke Iwane, Go Yamakawa, Mayuki Omatsu, Mio Namikawa, Makoto Sono, Tomonori Masuda, Yuichi Fukunaga, Munemasa Nagao, Osamu Araki, Takaaki Yoshikawa, Satoshi Ogawa, Yukiko Hiramatsu, Motoyuki Tsuda, Takahisa Maruno, Yuki Nakanishi, Dieter Saur, Tatsuaki Tsuruyama, Toshihiko Masui, Etsuro Hatano, Hiroshi Seno
Munenori Kawai, Akihisa Fukuda, Munehiro Ikeda, Kei Iimori, Kenta Mizukoshi, Kosuke Iwane, Go Yamakawa, Mayuki Omatsu, Mio Namikawa, Makoto Sono, Tomonori Masuda, Yuichi Fukunaga, Munemasa Nagao, Osamu Araki, Takaaki Yoshikawa, Satoshi Ogawa, Yukiko Hiramatsu, Motoyuki Tsuda, Takahisa Maruno, Yuki Nakanishi, Dieter Saur, Tatsuaki Tsuruyama, Toshihiko Masui, Etsuro Hatano, Hiroshi Seno
View: Text | PDF
Research Article Gastroenterology Oncology

Polybromo 1/vimentin axis dictates tumor grade, epithelial-mesenchymal transition, and metastasis in pancreatic cancer

Abstract

Mutations in Polybromo 1 (PBRM1), a subunit of the switch/sucrose nonfermentable (SWI/SNF) chromatin remodeling complex, are frequently observed in several cancers, including pancreatic ductal adenocarcinoma (PDAC). In this study, we demonstrated that pancreas-specific loss of Pbrm1 in mice harboring Kras mutations and Trp53 deletions accelerated the development of poorly differentiated PDAC, epithelial-mesenchymal transition (EMT), and metastasis, resulting in worsened prognosis. Pbrm1 loss in preexisting PDAC shifted the tumor grade from a well- to a poorly differentiated state and elevated vimentin expression. Pbrm1-null PDAC exhibited downregulation of apical junction genes and upregulation of EMT pathway genes, including the vimentin and squamous molecular subtype signature genes. Mechanistically, PBRM1 bound to the vimentin gene promoter and directly downregulated its expression. Furthermore, suppression of vimentin in Pbrm1-null PDAC cells reversed the dedifferentiation phenotype and reduced EMT and metastasis. Consistently, reduced PBRM1 expression correlated with high vimentin expression, poorly differentiated histology, a high recurrence rate, and reduced overall survival in human PDACs. Additionally, PDAC with PBRM1 deletion was associated with the aggressive squamous molecular subtype. Our data established PBRM1 as a tumor suppressor that controls tumor grade and metastasis of PDAC by regulating vimentin expression.

Authors

Munenori Kawai, Akihisa Fukuda, Munehiro Ikeda, Kei Iimori, Kenta Mizukoshi, Kosuke Iwane, Go Yamakawa, Mayuki Omatsu, Mio Namikawa, Makoto Sono, Tomonori Masuda, Yuichi Fukunaga, Munemasa Nagao, Osamu Araki, Takaaki Yoshikawa, Satoshi Ogawa, Yukiko Hiramatsu, Motoyuki Tsuda, Takahisa Maruno, Yuki Nakanishi, Dieter Saur, Tatsuaki Tsuruyama, Toshihiko Masui, Etsuro Hatano, Hiroshi Seno

×

Figure 7

Vimentin inhibition reverses the dedifferentiation phenotype and reduces metastasis of Pbrm1-null PDAC in mice.

Options: View larger image (or click on image) Download as PowerPoint
Vimentin inhibition reverses the dedifferentiation phenotype and reduces...
(A) Quantitative real-time PCR analysis of the relative mRNA expression of Zeb1, Vim, Snai1, Snai2, Twist1, Cldn7, and Dsg2 in KPC PDAC cells with shRNA knockdown of the vimentin gene (shVimentin) (n = 3) compared with KPC PDAC cells with shRNA control (shControl) (n = 3). *P < 0.05, Student t test. Data shown as mean ± SE. (B) Quantitative real-time PCR analysis of the relative mRNA expression of Zeb1, Vim, Snai1, Snai2, Twist1, Cldn7, and Dsg2 in KPCPb–/– PDAC cells with shRNA knockdown of the vimentin gene (shVimentin) (n = 3) compared with KPCPb–/– PDAC cells with shRNA control (shControl) (n = 3). *P < 0.05, paired t test. Data shown as mean ± SE. (C) Representative H&E staining in PDACs allografted subcutaneously with KPCshControl, KPCshVimentin, KPCPb–/–shControl, and KPCPb–/–shVimentin PDAC cells. Scale bar: 50 μm. Data are representative of 3 independent experiments. (D) Representative H&E and CK19 staining in metastatic PDAC after injection into the spleen with KPCshControl, KPCshVimentin, KPCPb–/–shControl, and KPCPb–/–shVimentin PDAC cells. Scale bar: 500 μm. Data are representative of 3 independent experiments. (E) Quantification of CK19-positive liver metastasis with splenic injection of KPC shControl (n = 3), KPCshVimentin (n = 3), KPCPb–/–shControl (n = 3), and KPCPb–/–shVimentin (n = 3) PDAC cells, determined by combining 3 independent sections. *P < 0.05, Student t test. Data are represented as mean ± SE. (F) Representative images of the scratch assay with KPC shControl, KPCshVimentin, KPCPb–/–shControl, and KPCPb–/–shVimentin PDAC cells. Data are representative of 3 independent experiments. (G) Quantification of the scratch assay with KPC shControl (n = 3), KPCshVimentin (n = 3), KPCPb–/–shControl (n = 3), and KPCPb–/–shVimentin (n = 3) PDAC cells. *P < 0.05, Student t test. Data shown as mean ± SE. (H) Quantification of CK19-positive liver metastasis in mice treated with simvastatin (n = 3), Withaferin A (n = 3), and each vehicle control (n = 3) with splenic injection of KPC and KPCPb–/– PDAC cells, determined by combining 3 independent sections. *P < 0.05, Student t test. Data are represented as mean ± SE. (I) Representative IHC analysis of PBRM1 and vimentin in human PDACs. Patient #1 shows high PBRM1 expression and low expression of vimentin. Patient #2 shows the low expression of PBRM1 and the high expression of vimentin. Scale bar: 50 μm. Data are representative of 3 independent experiments. (J) Analysis of high vimentin expression in human PDACs (n = 105) surgically resected with high (n = 50) or low (n = 55) PBRM1 expression as determined by IHC. *P < 0.05, Pearson’s χ2 test.