Combined inhibition of Notch and JAK/STAT is superior to monotherapies and impairs pancreatic cancer progression.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with a high rate of metastasis. Recent studies have indicated that Notch and janus kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT3) signaling pathways are both important for the initiation and progression of PDAC. The purpose of this study was to determine the outcome of targeting these two tumor signaling pathways simultaneously both in vitro and in vivo. We assessed the combinational effects of the γ-secretase inhibitor IX (GSI IX) and JAK2 inhibitor (AG-490) on growth and epithelial plasticity of human pancreatic cancer cell lines, and in a genetically engineered mouse model (Pdx1-Cre, LSL-KrasG12D, p53(lox/+)) of PDAC. Dual treatment with GSI IX and AG-490 significantly impaired cell proliferation, migration, invasion, soft agar growth and apoptosis when compared with monotherapies. Most importantly, combinational treatment significantly attenuates tumor progression in vivo and suppresses conversion from acinar-ductal-metaplasia to PDAC. Our results suggest that targeting Notch and JAK2/STAT3 signaling pathways simultaneously is superior to single inhibitions, supporting combined treatment by GSI IX and AG-490 as a potential therapeutic approach for PDAC. However, the study design limits the direct transfer into the clinic and the impact of dual treatment in patients with PDAC remains still to be determined.

Inhibition of hedgehog signaling attenuates carcinogenesis in vitro and increases necrosis of cholangiocellular carcinoma.

UNLABELLED: The Hedgehog signaling pathway plays a pivotal role during embryonic development, stem cell maintenance, and wound healing. Hedgehog signaling also is deregulated in many cancers. However, the role of this signaling pathway in the carcinogenesis of cholangiocarcinoma (CCC) is still unknown. In this study, we investigated the effects of Hedgehog inhibition by cyclopamine and 5E1 in cultured human CCC cell lines and in vivo using a xenograft mouse model. We also investigated the involvement of Hedgehog in epithelial to mesenchymal transition (EMT), migration, and CCC tumor growth. Sonic hedgehog (Shh) ligand was highly expressed in 89% of human CCC tissues and in CCC cell lines. Cyclopamine and 5E1 treatments effectively inhibited cell proliferation, migration, and invasion by down-regulating the Hedgehog target genes glioblastoma 1 and glioblastoma 2. In vitro and in vivo, we detected an increase in epithelial marker, E-cadherin, after Hedgehog inhibition. In addition, we saw an increase in necrotic areas and a decrease in mitotic figures in cyclopamine and 5E1-treated CCC xenograft tumors. CONCLUSION: This study supports the presence of autocrine Hedgehog signaling in human CCC, where CCC cells produce and respond to Shh ligand. Blocking the Hedgehog pathway inhibited EMT and decreased the viability of CCC cells. In addition, cyclopamine and 5E1 inhibited the growth of CCC xenograft tumors.

Correction: Activation of Notch Signaling Is Required for Cholangiocarcinoma Progression and Is Enhanced by Inactivation of p53 In Vivo.

[This corrects the article DOI: 10.1371/journal.pone.0077433.].

Correction: Capsaicin Treatment Attenuates Cholangiocarcinoma Carcinogenesis.

[This corrects the article DOI: 10.1371/journal.pone.0095605.].

Capsaicin treatment attenuates cholangiocarcinoma carcinogenesis.

UNLABELLED: Capsaicin, the most abundant pungent molecule produced by pepper plants, represents an important ingredient in spicy foods consumed throughout the world. Studies have shown that capsaicin can relieve inflammation and has anti-proliferative effects on various human malignancies. Cholangiocarcinoma (CC) is a cancer disease with rising incidence. The prognosis remains dismal with little advance in treatment. The aim of the present study is to explore the anti-tumor activity of capsaicin in cultured human CC cell lines. Capsaicin effectively impaired cell proliferation, migration, invasion, epithelial to mesenchymal transition and growth of softagar colonies. Further, we show that capsaicin treatment of CC cells regulates the Hedgehog signaling pathway. CONCLUSION: Our results provide a basis for capsaicin to improve the prognosis of CCs in vivo and present new insights into the effectiveness and mode of action of capsaicin.

The intestinal microbiota dysbiosis and Clostridium difficile infection: is there a relationship with inflammatory bowel disease?

Gut microbiota is a compilation of microorganisms dwelling in the entire mammalian gastrointestinal tract. They display a symbiotic relationship with the host contributing to its intestinal health and disease. Even a slight fluctuation in this equipoise may be deleterious to the host, leading to many pathological conditions like Clostridium difficile infection or inflammatory bowel disease (IBD). In this review, we focus on the role of microbial dysbiosis in initiation of C. difficile infection and IBD, and we also touch upon the role of specific pathogens, particularly C. difficile, as causative agents of IBD. We also discuss the molecular mechanisms activated by C. difficile that contribute to the development and exacerbation of gastrointestinal disorders.

Activation of Notch signaling is required for cholangiocarcinoma progression and is enhanced by inactivation of p53 in vivo.

UNLABELLED: Cholangiocacinoma (CC) is a cancer disease with rising incidence. Notch signaling has been shown to be deregulated in many cancers. However, the role of this signaling pathway in the carcinogenesis of CC is still not fully explored. In this study, we investigated the effects of Notch inhibition by γ-secretase inhibitor IX (GSI IX) in cultured human CC cell lines and we established a transgenic mouse model with liver specific expression of the intracellular domain of Notch (Notch-ICD) and inactivation of tumor suppressor p53. GSI IX treatment effectively impaired cell proliferation, migration, invasion, epithelial to mesenchymal transition and growth of softagar colonies. In vivo overexpression of Notch-ICD together with an inactivation of p53 significantly increased tumor burden and showed CC characteristics. CONCLUSION: Our study highlights the importance of Notch signaling in the tumorigenesis of CC and demonstrates that additional inactivation of p53 in vivo.

Decrease of CD44-positive cells correlates with tumor response to chemotherapy in patients with gastrointestinal cancer.

BACKGROUND/AIM: CD44 is a multistructural and multifunctional cell surface molecule which is involved in cell proliferation, differentiation, migration and angiogenesis. Here we investigated the potential role of CD44 in patients with metastasized pancreatic ductal adenocarcinoma, colorectal and stomach cancer, which were treated with different combinations of palliative chemotherapy. PATIENTS AND METHODS: CD44 expression was measured by flow cytometry in patients' (n=15) blood samples and the findings were correlated with CA19-9 expression and with computed tomography results. RESULTS: We found a significant correlation (p<0.05) between the CD44 decrease and the tumor response according to the tumor marker elevation/ response evaluation criteria in solid tumors. CONCLUSION: We were able to monitor changes of CD44 expression after chemotherapy and detected a correlation between the CD44 decrease and the patients' response to treatment. Our findings show that CD44 detection helps to monitor chemotherapy response in patients with gastrointestinal cancer.

Islet microarchitecture and glucose transporter expression of the pancreas of the marmoset monkey display similarities to the human.

The common marmoset New World monkey (Callithrix jacchus), is a primate model with great potential for scientific research, including research on diabetes. However, in opposite to Rhesus and Java monkeys (Macaca mulatta and Macaca fascicularis) little is known about the marmosets islet microarchitecture, glucose transporter and pancreatic marker gene expression. In this work we analyze differences and similarities in size, shape, cellular composition and intra-islet topography between the common marmoset and the human endocrine pancreas. Different sized, circular and a-circular shaped islets of the common marmoset and human display α-cells in the whole islet organ leading to a ribbon-like islet type. The number of islets was significantly higher in the common marmoset compared with humans. However, the area of insulin-producing cells was significantly higher in the human pancreas. Intra-islet distribution pattern of δ- and ß-cells was similar in both species. The morphology of the exocrine pancreas regarding acinar and ductal cells was quite similar as confirmed by ultrastructural analysis. Additionally the ultrastructure of secretory granules from α-, δ- and ß-cells of human and non-human primate pancreas showed the same characteristics. Molecular analysis showed the presence of endocrine pancreatic marker genes like PMCA2, NCX1, SUR1, KIR6.2, MAFA, NGN3 and PDX1 also expressed in the human. For the first time we could show presence of Glut 5 and 9 transporters in addition to the low abundance transporter Glut2 and the highly expressed Glut1 glucose transporter. We propose that Callithrix jacchus displays a new animal model for diabetes research and regenerative medicine.

Epithelial mesenchymal transition and pancreatic tumor initiating CD44+/EpCAM+ cells are inhibited by γ-secretase inhibitor IX.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with a high rate of metastasis. Recent studies have indicated that the Notch signalling pathway is important in PDAC initiation and maintenance, although the specific cell biological roles of the pathway remain to be established. Here we sought to examine this question in established pancreatic cancer cell lines using the γ-secretase inhibitor IX (GSI IX) to inactivate Notch. Based on the known roles of Notch in development and stem cell biology, we focused on effects on epithelial mesenchymal transition (EMT) and on pancreatic tumor initiating CD44+/EpCAM+ cells. We analyzed the effect of the GSI IX on growth and epithelial plasticity of human pancreatic cancer cell lines, and on the tumorigenicity of pancreatic tumor initiating CD44+/EpCAM+ cells. Notably, apoptosis was induced after GSI IX treatment and EMT markers were selectively targeted. Furthermore, under GSI IX treatment, decline in the growth of pancreatic tumor initiating CD44+/EpCAM+ cells was observed in vitro and in a xenograft mouse model. This study demonstrates a central role of Notch signalling pathway in pancreatic cancer pathogenesis and identifies an effective approach to inhibit selectively EMT and suppress tumorigenesis by eliminating pancreatic tumor initiating CD44+/EpCAM+ cells.

Inflammatory tendencies and overproduction of IL-17 in the colon of young NOD mice are counteracted with diet change.

OBJECTIVE: Dietary factors influence diabetes development in the NOD mouse. Diet affects the composition of microbiota in the distal intestine, which may subsequently influence intestinal immune homeostasis. However, the specific effects of antidiabetogenic diets on gut immunity and the explicit associations between intestinal immune disruption and type 1 diabetes onset remain unclear. RESEARCH DESIGN AND METHODS: Gut microbiota of NOD mice fed a conventional diet or ProSobee formula were compared using gas chromatography. Colonic lamina propria immune cells were characterized in terms of activation markers, cytokine mRNA and Th17 and Foxp3(+) T-cell numbers, using real-time PCR and flow cytometry. Activation of diabetogenic CD4 T-cells by purified B-cells was assessed in both groups. Immune tolerance to autologous commensal bacteria was evaluated in vitro using thymidine-incorporation tests. RESULTS: Young NOD mice showed a disturbed tolerance to autologous commensal bacteria. Increased numbers of activated CD4 T-cells and (CD11b(+)CD11c(+)) dendritic cells and elevated levels of Th17 cells and IL23 mRNA were moreover observed in colon lamina propria. These phenomena were abolished when mice were fed an antidiabetogenic diet. The antidiabetogenic diet also altered the expression levels of costimulatory molecules and the capacity of peritoneal B-cells to induce insulin-specific CD4 T-cell proliferation. CONCLUSIONS: Young NOD mice show signs of subclinical colitis, but the symptoms are alleviated by a diet change to an antidiabetogenic diet. Disrupted immune tolerance in the distal intestine may influence peritoneal cell pools and B-cell-mediated activation of diabetogenic T-cells.