ONCOGENIC RAS PATHWAY MEDIATED CREB ACTIVATION PROMOTES THE DEVELOPMENT OF PANCREATIC NEOPLASIA IN SMOKERS
Abstract
OBJECTIVE: Long-term smoking is strongly associated with the risk of development of pancreatic cancer (PC). Among multiple tobacco specific nitrosamines, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is considered to be... [ view full abstract ]
OBJECTIVE: Long-term smoking is strongly associated with the risk of development of pancreatic cancer (PC). Among multiple tobacco specific nitrosamines, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is considered to be most carcinogenic. This study describes the molecular mechanism of tobacco induced pancreatic carcinogenesis.
METHODS: Immortalized human pancreatic epithelial (HPNE) and its respective mutant Kras (HPNE-Kras), cells were treated with NNK in a dose-dependent manner and immunoblotted for phosphorylated CREB (pCREB). Human tissue microarray analysis was performed to determine the significance of pCREB expression amongst smokers and non-smokers. Serum from KPC (LSL-KrasG12D/+; Trp53R172H/+; Pdx1Cre/+) and KC (LSL-KrasG12D/+; Pdx1Cre/+) mice were analyzed for their respective levels of cytokines with in vivo smoking. PC cells were treated with NNK and subjected to MEK inhibition (MEKi), which were immunoblotted for phosphorylation of kinases downstream of Kras. Xenograft of KPC mouse line K8484 was treated with NNK with or without MEK inhibitor (Trametinib) and assessed for in vivo tumor growth.
RESULTS: Exposure of HPNE, HPNE KRas and PanIN cells to NNK resulted in dose-dependent elevation of pCREB expression. RNA-seq analysis was confirmed activation of CREB in NNK treated cells. Expression of pCREB was significantly higher (p<0.001) in smokers when compared to non-smokers. CREB knockdown cells showed significantly decreased tumor growth and tumor cell proliferation in vivo with NNK, confirming the role of CREB (downstream Kras) in NNK- induced pancreatic tumorigenecity.
CONCLUSIONS: Our study demonstrates that NNK induces pancreatic tumorigenesis by activating CREB through MEK-ERK signaling. Therefore, CREB can serve as a novel therapeutic target for PC.
Authors
-
Supriya Srinivasan
(University of Miami – Miller School of Medicine, Miami, Florida, USA)
-
Tulasigeri Totiger
(University of Miami – Miller School of Medicine, Miami, Florida, USA)
-
Jason Castellanos
(Vanderbilt University Medical Center)
-
Purushottam Lamichhane
(University of Miami – Miller School of Medicine, Miami, Florida, USA)
-
Fanuel Messaggio
(University of Miami – Miller School of Medicine, Miami, Florida, USA)
-
Alexander Gaidarski
(University of Miami – Miller School of Medicine, Miami, Florida, USA)
-
Chanjuan Shi
(Vanderbilt University)
-
Nipun Merchant
(University of Miami – Miller School of Medicine, Miami, Florida, USA)
-
Michael VanSaun
(University of Miami – Miller School of Medicine, Miami, Florida, USA)
-
Nagaraj Nagathihalli
(University of Miami – Miller School of Medicine, Miami, Florida, USA)
Topic Area
Surgical Oncology
Session
QS-SurgOnc » Quick-Shot Presentations: Surgical Oncology (15:00 - Thursday, 21st September, Lee 404)