Transforming growth factor-ß adaptor, ß2-spectrin, modulates cyclin dependent kinase 4 to reduce development of hepatocellular cancer.

UNLABELLED: Transforming growth factor beta (TGF-ß) is an important regulator of cell growth, and loss of TGF-ß signaling is a hallmark of carcinogenesis. The Smad3/4 adaptor protein ß2-spectrin (ß2SP) is emerging as a potent regulator of tumorigenesis through its ability to modulate the tumor suppressor function of TGF-ß. However, to date the role of the TGF-ß signaling pathway at specific stages of the development of hepatocellular carcinoma (HCC), particularly in relation to the activation of other oncogenic pathways, remains poorly delineated. Here we identify a mechanism by which ß2SP, a crucial Smad3 adaptor, modulates cyclin dependent kinase 4 (CDK4), cell cycle progression, and suppression of HCC. Increased expression of ß2SP inhibits phosphorylation of the retinoblastoma gene product (Rb) and markedly reduces CDK4 expression to a far greater extent than other CDKs and cyclins. Furthermore, suppression of CDK4 by ß2SP efficiently restores Rb hypophosphorylation and cell cycle arrest in G(1) . We further demonstrate that ß2SP interacts with CDK4 and Smad3 in a competitive and TGF-ß-dependent manner. In addition, haploinsufficiency of cdk4 in ß2sp(+/-) mice results in a dramatic decline in HCC formation compared to that observed in ß2sp(+/-) mice. CONCLUSION: ß2SP deficiency leads to CDK4 activation and contributes to dysregulation of the cell cycle, cellular proliferation, oncogene overexpression, and the formation of HCCs. Our data highlight CDK4 as an attractive target for the pharmacologic inhibition of HCC and demonstrate the importance of ß2sp(+/-) mice as a model of preclinical efficacy in the treatment of HCC.

Small bowel adenocarcinoma.

Small bowel cancers are rare, accounting for only about 6000 cases/year in the United States, approximately 25% of which are small bowel adenocarcinomas. Small bowel adenocarcinomas have traditionally been considered to be highly fatal due to their nonspecific presentation at the time of diagnosis, and to the lack of responsiveness to older chemotherapy regimens. However, that paradigm may be changing. Newer diagnostic techniques such as video capsule and double balloon enteroscopy may facilitate earlier diagnosis. In addition, modern chemotherapy regimens have produced improved response rates and survival rates, when compared to historical controls. Still, there remains great need for multi-institutional, cooperative group studies to define the optimal treatment of small bowel adenocarcinoma, both in the adjuvant and advanced/metastatic setting.

Rotational assisted endoscopic retrograde cholangiopancreatography in patients with reconstructive gastrointestinal surgical anatomy.

AIM: To evaluate the success rates of performing therapy utilizing a rotational assisted enteroscopy device in endoscopic retrograde cholangiopancreatography (ERCP) in surgically altered anatomy patients. METHODS: Between June 1, 2009 and November 8, 2012, we performed 42 ERCPs with the use of rotational enteroscopy for patients with altered anatomy (39 with gastric bypass Roux-en-Y, 2 with Billroth II gastrectomy, and 1 with hepaticojejunostomy associated with liver transplant). The indications for ERCP were: choledocholithiasis: 13 of 42 (30.9%), biliary obstruction suggested on imaging: 20 of 42 (47.6%), suspected sphincter of Oddi dysfunction: 4 of 42 (9.5%), abnormal liver enzymes: 1 of 42 (2.4%), ascending cholangitis: 2 of 42 (4.8%), and bile leak: 2 of 42 (4.8%). All procedures were completed with the Olympus SIF-Q180 enteroscope and the Endo-Ease Discovery SB overtube produced by Spirus Medical. RESULTS: Successful visualization of the major ampulla was accomplished in 32 of 42 procedures (76.2%). Cannulation of the bile duct was successful in 26 of 32 procedures reaching the major ampulla (81.3%). Successful therapeutic intervention was completed in 24 of 26 procedures in which the bile duct was cannulated (92.3%). The overall intention to treat success rate was 64.3%. In terms of cannulation success, the intention to treat success rate was 61.5%. Ten out of forty two patients (23.8%) required admission to the hospital after procedure for abdominal pain and nausea, and 3 of those 10 patients (7.1%) had a diagnosis of post-ERCP pancreatitis. The average hospital stay was 3 d. CONCLUSION: It is reasonable to consider an attempt at rotational assisted ERCP prior to a surgical intervention to alleviate biliary complications in patients with altered surgical anatomy.