The epigenetic regulators Bmi1 and Ring1B are differentially regulated in pancreatitis and pancreatic ductal adenocarcinoma.
Chronic pancreatitis and pancreatic ductal adenocarcinoma (PDAC) are associated with major changes in cell differentiation. These changes may be at the basis of the increased risk for PDAC among patients with chronic pancreatitis. Polycomb proteins are epigenetic silencers expressed in adult stem cells; up-regulation of Polycomb proteins has been reported to occur in a variety of solid tumours such as colon and breast cancer. We hypothesized that Polycomb might play a role in preneoplastic states in the pancreas and in tumour development/progression. To test these ideas, we determined the expression of PRC1 complex proteins (Bmi1 and Ring1b) during pancreatic development and in pancreatic tissue from mouse models of disease: acute and chronic pancreatic injury, duct ligation, and in K-Ras(G12V) conditional knock-in and caerulein-treated K-Ras(G12V) mice. The study was extended to human pancreatic tissue samples. To obtain mechanistic insights, Bmi1 expression in cells undergoing in vitro exocrine cell metaplasia and the effects of Bmi1 depletion in an acinar cancer cell line were studied. We found that Bmi1 and Ring1B are expressed in pancreatic exocrine precursor cells during early development and in ductal and islet cells-but not acinar cells-in the adult pancreas. Bmi1 expression was induced in acinar cells during acute injury, in acinar-ductal metaplastic lesions, as well as in pancreatic intraepithelial neoplasia (PanIN) and PDAC. In contrast, Ring1B expression was only significantly and persistently up-regulated in high-grade PanINs and in PDAC. Bmi1 knockdown in cultured acinar tumour cells led to changes in the expression of various digestive enzymes. Our results suggest that Bmi1 and Ring1B are modulated in pancreatic diseases and could contribute differently to tumour development.
Martínez-Romero
Carles
C
Institut Municipal d'Investigació Mèdica, Hospital del Mar, Barcelona, Spain.
Rooman
Ilse
I
Skoudy
Anouchka
A
Guerra
Carmen
C
Molero
Xavier
X
González
Ana
A
Iglesias
Mar
M
Lobato
Tania
T
Bosch
Almudena
A
Barbacid
Mariano
M
Real
Francisco X
FX
Hernández-Muñoz
Inmaculada
I
D000208:Acute Disease; D000818:Animals; D021441:Carcinoma, Pancreatic Ductal / Q000378:metabolism*; D002478:Cells, Cultured; D004195:Disease Models, Animal; D006801:Humans; D008297:Male; D008679:Metaplasia / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009687:Nuclear Proteins / Q000378:metabolism*; D010179:Pancreas / Q000378:metabolism; D046790:Pancreas, Exocrine / Q000378:metabolism / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D010195:Pancreatitis / Q000378:metabolism; D050500:Pancreatitis, Chronic / Q000378:metabolism*; D063150:Polycomb Repressive Complex 1; D011230:Precancerous Conditions / Q000378:metabolism / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012097:Repressor Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism
C069077:BMI1 protein, human; C489421:Bmi1 protein, mouse; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C062602:transcription factor PTF1; D063150:Polycomb Repressive Complex 1