Keratin 8 reduces colonic permeability and maintains gut microbiota homeostasis, protecting against colitis and colitis-associated tumorigenesis.

Keratin 8 (CK8) is the major component of the intermediate filaments of simple or single-layered epithelia. Gene targeting mice model suggest that CK8 is involved in colonic active ion transport, colorectal hyperplasia and inflammation. In the present study, we found that CK8 is downregulated in the colon during DSS-induced colitis and AOM/DSS-induced colitis-associated colorectal cancer (CAC) development. In human patients with colon cancer, CK8 is downregulated. Using CK8 heterozygous knockout mice (CK8+/-), we found that CK8+/- mice are highly susceptible to DSS-induced colitis and more prone to AOM/DSS-induced CAC than wild type (WT) mice. The colonic permeability is increased with DSS or AOM/DSS treatment, leading to alteration of gut microbiota in CK8+/- mice with CAC. Metagenomic analysis of fecal microbiota suggests Firmicutes and Proteobacteria are increased in CK8+/- mice with CAC, while Bacteroidetes and Verrucomicrobia are decreased. Antibiotic treatment decreases the incidence of colorectal cancer tumorigenesis and TLR4 inhibitor attenuates the susceptibility of CK8+/- mice to DSS-induced colitis. These data suggest CK8 protects mice from colitis and colitis-associated colorectal cancer by modulating colonic permeability and gut microbiota composition homeostasis.

Clinicopathological Features of Intraductal Pancreatic Neuroendocrine Tumors.

Objective To evaluate the clinical and pathologic characteristics of intraductal pancreatic neuroendocrine tumors (PanNETs). Methods Four cases of intraductal PanNETs were studied by light microscopy and immunohistochemistry with the analysis of morphologic features and review of relevant literatures. Results Two female patients and two male patients aged 41- 58 years were enrolled in this study. The chief complaint was abdominal pain in two patients,vomiting in one patient,and jaundice in the last patient. Imaging examination showed intraductal neoplasm with diagnosis as intraductal papillary mucinous neoplasm (IPMN) in case 1; space-occupying lesions were found in the head of pancreas in the other three cases with pancreatic ductal ectasia and distal pancreatic atrophy. Grossly the masses were located in pancreatic main duct and invaded into surrounding pancreatic parachyma. Microscopically the tumors arranged with solid pattern,with some trabecular structures in the last two cases. Small duct and ductules were seen in intraductal PanNETs. The immunohistochemical expression showed that SYN and CgA were positive in neoplastic cells and negative in small duct and ductules.Conclusions Intraductal PanNETs are rare conditions. The clinical symptoms and imaging findings are similar to IPMN or pancreatic carcinoma. The tumors are located within pancreatic duct partly and can invade the pancreatic parenchyma. Microscopically the neuroendocrine tumors mix with small duct and forms ductulo-insular structure,which should be differentiated with mixed ductal endocrine carcinoma. The grade and prognosis are similar to those of classical neuroendocrine tumors.

Keratin 8 limits TLR-triggered inflammatory responses through inhibiting TRAF6 polyubiquitination.

Toll-like receptors (TLRs) have critical roles in innate immunity and inflammation and the detailed mechanisms by which TLR signaling is fine tuned remain unclear. Keratin 8 (CK8) belongs to the type II keratin family and is the major compontent of the intermediate filaments of simple or single-layered epithelia. Here we report that down-regulation of CK8 in mice enhanced TLR-mediated responses, rendering mice more susceptible to lipopolysaccharide (LPS)-induced endotoxin shock and Escherichia coli-caused septic peritonitis with reduced survival, elevated levels of inflammation cytokines and more severe tissue damage. We found that CK8 suppressed TLR-induced nuclear factor (NF)-κB activation and interacted with the adaptor tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) to prevent its polyubiquitination. Our findings demonstrate a novel role of CK8 in negative regulation of TLR/NF-κB signaling and highlight a previously unidentified nonclassical function for CK8 in limiting inflammatory responses.

Ectopic adrenocorticotropic hormone syndrome caused by neuroendocrine tumors of the thymus: 30-year experience with 16 patients at a single institute in the People's Republic of China.

BACKGROUND AND PURPOSE: Thymic neuroendocrine carcinomas (TNECs) are extremely uncommon. Certain cases of TNECs can produce the adrenocorticotropic hormone (ACTH) and cause ectopic ACTH syndrome (EAS). The current literature on this topic consists mainly of case reports, and therapeutic guidelines are lacking. The aim of this study was to discuss the diagnosis, surgical management, and prognosis of EAS caused by TNECs to improve clinical experience with this rare disease. METHODS: From June 1984 to June 2014, at the Peking Union Medical College Hospital, the surgical interventions and follow-up outcomes of 16 consecutive patients (eight men and eight women) with EAS caused by TNECs were retrospectively analyzed. RESULTS: The median age was 32.5 years (range: 13-47 years), and the median disease duration was 8.5 months (range: 1-150 months). All patients presented with clinical and biochemical evidence indicating a diagnosis of Cushing's syndrome. Contrast-enhanced thoracic computed tomography scans were critical to locating the ACTH-producing tumor and evaluating the feasibility of resection. All patients underwent surgery. One patient died of septicemia in the intensive care unit 2 weeks after surgery. No other morbidity or mortality occurred during the perioperative period. The median overall survival (OS) was 41 months (95% CI: 30.3-51.7 months), and the progression-free survival was 28 months (95% CI: 21.6-34.3 months). Both overall survival (P=0.002) and progression-free survival (P=0.030) improved significantly after complete resection. CONCLUSION: TNEC is an extremely aggressive disease that should be considered when treating patients with Cushing's syndrome due to ectopic ACTH secretion. In particular, all suspected patients should undergo contrast-enhanced thoracic computed tomography scans to facilitate early diagnosis. The current first-line treatment is surgical resection, and complete resection is a favorable prognostic factor. However, additional patients and a longer follow-up will be needed to determine the variables that are predictive of survival and to improve patient prognosis.

[Effects of ezrin silencing on pancreatic cancer cell line Panc-1].

OBJECTIVE: To explore the effects of ezrin silencing on pancreatic cancer cell line Panc-1. METHODS: Pancreatic cancer cell line Panc-1 was transfected with ezrin silencing plasmid. The proliferation and the cell cycle status were determined by CCK-8 assay and flow cytometry analysis, respectively. Cellular membrane protrusions/microvilli formation were visualized by scanning election microscopy. Colony formation assay was used to determine the cell anchor-independent growth ability in vitro. Trans-filter migration and invasion assays were performed with 8 µm pore inserts in a 24-well BioCoat chamber with/without Matrigel. RESULTS: Ezrin silencing decreased cellular protrusions/microvilli formation, anchorage-independent growth, cell migration and invasion, but had no effects on cell proliferation in vitro and cell cycle, in pancreatic cancer cell line Panc-1. CONCLUSION: Ezrin expression affects the cellular protrusions/microvilli formation, anchorage-independent growth, cell migration and invasion in pancreatic cancer cell line Panc-1.

Beta-catenin up-regulates the expression of cyclinD1, c-myc and MMP-7 in human pancreatic cancer: relationships with carcinogenesis and metastasis.

AIM: To investigate whether abnormal expression of beta-catenin in conjunction with overexpression of cyclinD1, c-myc and matrix metalloproteinase-7 (MMP-7) correlated with the carcinogenesis, metastasis and prognosis of pancreatic cancer, and to analyze the relationship of beta-catenin expression with cyclinD1, c-myc and MMP-7 expression. METHODS: Using immunohistochemistry, we examined the expression of beta-catenin, cyclinD1, c-myc and MMP-7 in 47 pancreatic adenocarcinoma tissues, 12 pancreatic intraepithelial neoplasia (PanIN) and 10 normal pancreases, respectively. Proliferation cell nuclear antigen was also tested as the index of proliferative activity of pancreatic cancer cells. RESULTS: In 10 cases of normal pancreatic tissues, epithelial cells showed equally strong membranous expression of beta-catenin protein at the cell-cell boundaries, but the expression of cyclinD1, c-myc and MMP-7 was negative. The expression of beta-catenin, cyclinD1, c-myc and MMP-7 in PanIN and pancreatic adenocarcinoma tissues had no significant difference [6/12 and 32/47 (68.1%), 6/12 and 35/47 (74.5%), 5/12 and 33/47 (70.2%), 7/12 and 30/47 (63.8%), respectively]. The abnormal expression of beta-catenin was significantly correlated to metastasis and one-year survival rate of pancreatic cancer, but had no relation with size, differentiation and cell proliferation. The expression of cyclinD1 was correlated with cell proliferation and extent of differentiation, but not with size, metastasis and one-year survival rate of the pancreatic cancer. The expression of c-myc was not correlated with size, extent of differentiation, metastasis and 1-year survival rate, but closely with cell proliferation of pancreatic cancer. The overexpression of MMP-7 was significantly associated with metastasis and 1-year survival rate of pancreatic cancer, but not with size, extent of differentiation and cell proliferation. There was a highly significant positive association between abnormal expression of beta-catenin and overexpression of cyclinD1, c-myc and MMP-7 not only in PanIN (r = 1.000, 0.845, 0.845), but also in pancreatic cancer (r = 0.437, 0.452, 0.435). CONCLUSION: The abnormal expression of beta-catenin plays a key role in the carcinogenesis and progression of human pancreatic carcinoma by up-regulating the expression of cyclinD1, c-myc and MMP-7, resulting in the degradation of extracellular matrix and uncontrolled cell proliferation and differentiation. beta-catenin abnormal expression and MMP-7 overexpression may be considered as two useful markers for determining metastasis and prognosis of human pancreatic cancer.

Relationship between expressions of E-cadherin and alpha-catenin and biological behaviors of human pancreatic cancer.

OBJECTIVES: To investigate the expressions of E-cadherin and alpha-catenin in pancreatic carcinoma and their relationship with biological behaviors, and clarify the mechanism of invasion and metastasis of pancreatic cancer. METHODS: The expressions of E-cadherin and alpha-catenin was examined in 47 patients with infiltrative ductal adenocarcinoma of the pancreas and 12 specimens of normal pancreatic tissues by immunohistochemical technique (PicTure( trade mark ) two-step method). Proliferation cell nuclear antigen (PCNA) was tested as an index of the proliferation degree of pancreatic cancer cells. RESULTS: The immunoreactivity of E-cadherin and alpha-catenin was expressed by normal ductal and acinar cells with strong membranous staining at the intercellular border in 12 specimens of normal pancreatic tissues. The abnormal rate of E-cadherin expression in pancreatic cancer was 53.2% (25/47), and it was significantly related to differentiation, high proliferation degree and lymph node and liver metastases (P<0.01, 0.05, 0.05 and 0.01, respectively). 61.7% patients with pancreatic cancer (29/47) showed abnormal expression of alpha-catenin. There was a good correlation among alpha-catenin expression, histological grade, and lymph node and liver metastases (P<0.05,0.05 and 0.01, respectively). No significant association was found among abnormal expressions of E-cadherin and alpha-catenin, tumor size, invasion, and 1-year survival rate of patients (P>0.05, all). There was a positive relationship between the expressions of E-cadherin and alpha-catenin in the 47 patients with pancreatic cancer (P<0.01, r=0.88). CONCLUSIONS: Pancreatic cancer likely occurs in case of the inactivation of E-cadherin and alpha-catenin genes and abnormal expression of proteins, which significantly correlate with tumorigenesis, proliferation, differentiation, and lymph node or liver metastasis of pancreatic cancer.