P53 gene mutation increases progastrin dependent colonic proliferation and colon cancer formation in mice.

Transgenic mice overexpressing human progastrin (hGAS) show colonic crypt hyper-proliferation and elevated susceptibility to colon carcinogenesis. We aimed to investigate effects of p53 mutation on colon carcinogenesis in hGAS mice. We show that introducing a p53 gene mutation further increases progastrin dependent BrdU labeling and results in markedly elevated number of aberrant crypt foci (ACF) and colonic tumors. We demonstrate that hGAS/Lgr5-GFP mice have higher number of Lgr5+ colonic stem cells per crypt when compared to Lgr5-GFP mice indicating that progastrin changes crypt biology through increased stem cell numbers and additional p53 mutation leads to more aggressive phenotype in this murine colon cancer model.

Inactivating cholecystokinin-2 receptor inhibits progastrin-dependent colonic crypt fission, proliferation, and colorectal cancer in mice.

Hyperproliferation of the colonic epithelium, leading to expansion of colonic crypt progenitors, is a recognized risk factor for colorectal cancer. Overexpression of progastrin, a nonamidated and incompletely processed product of the gastrin gene, has been shown to induce colonic hyperproliferation and promote colorectal cancer in mice, but the mechanism of pathogenesis has not been defined. Cholecystokinin-2 receptor (CCK2R) is the primary receptor for cholecystokinin (CCK) and amidated gastrin. Here, we show that Cck2r was expressed in murine colonic crypts and upregulated in the transgenic mice that overexpress human progastrin. Murine deletion of Cck2r abrogated progastrin-dependent increases in colonic proliferation, mucosal thickness, and beta-catenin and CD44 expression in the colon tumor. In addition, either deletion or antagonism of Cck2r resulted in the inhibition of progastrin-dependent increases in progenitors expressing doublecortin and CaM kinase-like-1 (DCAMKL1), stem cells expressing leucine rich repeat-containing G protein-coupled receptor 5 (LgR5), and colonic crypt fission. Furthermore, in the azoxymethane mouse model of colorectal carcinogenesis, Cck2r deletion in human progastrin-overexpressing mice resulted in markedly decreased aberrant crypt foci formation and substantially reduced tumor size and multiplicity. Taken together, these observations indicate that progastrin induces proliferative effects, primarily in colonic progenitor cells, through a CCK2R-dependent pathway. Moreover, our data suggest that CCK2R may be a potential target in the treatment or prevention of colorectal cancer.

Effect of warm ischemia time during laparoscopic partial nephrectomy on early postoperative glomerular filtration rate.

PURPOSE: We evaluated the effect of warm ischemia time on early postoperative renal function following laparoscopic partial nephrectomy. MATERIALS AND METHODS: Of 453 patients who were surgically treated for renal tumors between May 2001 and September 2007, and who were identified in our database 128 underwent laparoscopic partial nephrectomy. Of these 128 patients 101 who were evaluable had complete demographic, operative, preoperative and early postoperative data available. Renal function was estimated using the glomerular filtration rate. Warm ischemia time was stratified into 4 interval groups and also analyzed based on different time cutoffs. Ultimately we also tested the relationship between postoperative renal failure, and preoperative factors and warm ischemia time. RESULTS: Warm ischemia time interval analysis was not significant. However, when analyzing the effect of warm ischemia time cutoffs, patients with warm ischemia time greater than 40 minutes had a significantly greater decrease in the glomerular filtration rate (p = 0.03) and a lower glomerular filtration rate postoperatively. The incidence of renal function impairment was more than 2-fold higher in those with a warm ischemia time of greater than 40 minutes than in the other groups (p = 0.077). Warm ischemia time was significant on univariate analysis when only patients with a preoperative glomerular filtration rate of 60 ml per minute per 1.73 m(2) or greater were analyzed. However, this did not hold as an independent predictor of postoperative renal function impairment on multivariate analysis. The preoperative glomerular filtration rate was the only independent predictor of postoperative renal function impairment. CONCLUSIONS: A warm ischemia time of 40 minutes appears to be an appropriate cutoff, after which a significantly greater decrease in renal function occurs after laparoscopic partial nephrectomy. The preoperative glomerular filtration rate was the only independent predictor of an increased risk of renal insufficiency following laparoscopic partial nephrectomy.

Overexpression of interleukin-1beta in the murine pancreas results in chronic pancreatitis.

BACKGROUND & AIMS: Chronic pancreatitis is a significant cause of morbidity and a known risk factor for pancreatic adenocarcinoma. Interleukin-1beta is a proinflammatory cytokine involved in pancreatic inflammation. We sought to determine whether targeted overexpression of interleukin-1beta in the pancreas could elicit localized inflammatory responses and chronic pancreatitis. METHODS: We created a transgenic mouse model (elastase sshIL-1beta) in which the rat elastase promoter drives the expression of human interleukin-1beta. Mice were followed up for up to 2 years. Pancreata of elastase sshIL-1beta mice were analyzed for chronic pancreatitis-associated histologic and molecular changes. To study the potential effect of p53 mutation in chronic pancreatitis, elastase sshIL-1beta mice were crossed with p53(R172H) mice. RESULTS: Three transgenic lines were generated, and in each line the pancreas was atrophic and occasionally showed dilation of pancreatic and biliary ducts secondary to proximal fibrotic stenosis. Pancreatic histology showed typical features of chronic pancreatitis. There was evidence for increased acinar proliferation and apoptosis, along with prominent expression of tumor necrosis factor-alpha; chemokine (C-X-C motif) ligand 1; stromal cell-derived factor 1; transforming growth factor-beta1; matrix metallopeptidase 2, 7, and 9; inhibitor of metalloproteinase 1; and cyclooxygenase 2. The severity of the lesions correlated well with the level of human interleukin-1beta expression. Older mice displayed acinar-ductal metaplasia but did not develop mouse pancreatic intraepithelial neoplasia or tumors. Elastase sshIL-1beta*p53(R172H/+) mice had increased frequency of tubular complexes, some of which were acinar-ductal metaplasia. CONCLUSIONS: Overexpression of interleukin-1beta in the murine pancreas induces chronic pancreatitis. Elastase sshIL-1beta mice consistently develop severe chronic pancreatitis and constitute a promising model for studying chronic pancreatitis and its relationship with pancreatic adenocarcinoma.