TY - JOUR
T1 - The OGF-OGFr axis utilizes the p21 pathway to restrict progression of human pancreatic cancer
AU - Cheng, Fan
AU - McLaughlin, Patricia J.
AU - Verderame, Michael F.
AU - Zagon, Ian S.
N1 - Funding Information:
Supported by a grant from Philip Morris USA Inc. and Philip Morris International. We are grateful for the technical support of Ms. Renee Donahue for the siRNA experiments.
PY - 2008/1/11
Y1 - 2008/1/11
N2 - Background: Pancreatic cancer is the 4th leading cause of death from cancer in the U.S. The opioid growth factor (OGF; [Me5 ]-enkephalin) and the OGF receptor form an inhibitory growth regulatory system involved in the pathogenesis and treatment of pancreatic cancer. The OGF-OGFr axis influences the G0/G1 phase of the cell cycle. In this investigation, we elucidate the pathway of OGF in the cell cycle. Results: Using BxPC-3 cells, OGF decreased phosphorylation of retinoblastoma (Rb) protein without changing total Rb. This change was correlated with reduced cyclin-dependent kinase protein (Cdk) 2 kinase activity, but not total Cdk2. OGF treatment increased cyclin-dependent kinase inhibitor (CKI) p21 protein expression in comparison to controls, as well levels of p21 complexed with Cdk2. Naloxone abolished the increased expression of p21 protein by OGF, suggesting a receptor-mediated activity. p21 specific siRNAs blocked OGF's repressive action on proliferation in BxPC-3, PANC-1, and Capan-2 cells; cells transfected with negative control siRNA had no alteration in p21 expression, and therefore were inhibited by OGF. Conclusion: These data are the first to reveal that the target of cell proliferative inhibitory action of OGF in human pancreatic cancer is a p21 CKI pathway, expanding strategies for diagnosis and treatment of these neoplasias.
AB - Background: Pancreatic cancer is the 4th leading cause of death from cancer in the U.S. The opioid growth factor (OGF; [Me5 ]-enkephalin) and the OGF receptor form an inhibitory growth regulatory system involved in the pathogenesis and treatment of pancreatic cancer. The OGF-OGFr axis influences the G0/G1 phase of the cell cycle. In this investigation, we elucidate the pathway of OGF in the cell cycle. Results: Using BxPC-3 cells, OGF decreased phosphorylation of retinoblastoma (Rb) protein without changing total Rb. This change was correlated with reduced cyclin-dependent kinase protein (Cdk) 2 kinase activity, but not total Cdk2. OGF treatment increased cyclin-dependent kinase inhibitor (CKI) p21 protein expression in comparison to controls, as well levels of p21 complexed with Cdk2. Naloxone abolished the increased expression of p21 protein by OGF, suggesting a receptor-mediated activity. p21 specific siRNAs blocked OGF's repressive action on proliferation in BxPC-3, PANC-1, and Capan-2 cells; cells transfected with negative control siRNA had no alteration in p21 expression, and therefore were inhibited by OGF. Conclusion: These data are the first to reveal that the target of cell proliferative inhibitory action of OGF in human pancreatic cancer is a p21 CKI pathway, expanding strategies for diagnosis and treatment of these neoplasias.
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U2 - 10.1186/1476-4598-7-5
DO - 10.1186/1476-4598-7-5
M3 - Article
C2 - 18190706
AN - SCOPUS:39749099347
VL - 7
JO - Molecular Cancer
JF - Molecular Cancer
SN - 1476-4598
M1 - 5
ER -