Shinsuke Funakoshi

Granulocytapheresis is useful as an alternative therapy in patients with steroid-refractory or -dependent ulcerative colitis

Background:Recently, granulocyte and monocyte adsorption apheresis (GCAP) has been shown to be safe and effective for active ulcerative colitis (UC). We analyzed the safety and efficacy of GCAP (G-1 Adacolumn) in patients with steroid-refractory and -dependent UC. G-1 Adacolumn is filled with cellulose acetate carriers that selectively adsorb granulocytes and monocytes/macrophages. Methods:Forty-four patients with UC were treated with GCAP. These patients received 5 apheresis sessions over 4 weeks. Twenty patients had steroid-refractory UC (group 1) and 10 had steroid-dependent UC (group 2). Fourteen patients who did not want re-administration of steroids were treated with GCAP at the time of relapse, just after discontinuation of steroid therapy (group 3). Results:Of 44 patients treated with GCAP, 24 (55%) obtained remission (CAI ≤ 4), 9 (20%) showed a clinical response, and 11 (25%) remained unchanged. Only 2 of 10 patients (20%) with severe steroid-refractory UC (CAI ≥ 12) achieved remission, whereas 7 of 10 patients (70%) with moderate steroid-refractory UC achieved remission (p < 0.05). The dose of corticosteroids was tapered in 9 of 10 (90%) patients with steroid-dependent UC after GCAP therapy. Twelve (86%) of 14 patients in group 3 showed an improvement in symptoms and could avoid re-administration of steroids after GCAP. No severe adverse effects occurred. Conclusions:The findings of this study suggest that GCAP may be a useful alternative therapy for patients with moderate steroid-refractory or -dependent UC, although cyclosporin A or colectomy is necessary in patients with severe UC. GCAP may also be useful for avoiding re-administration of steroids at the time of relapse. Randomized, controlled clinical trials are needed to confirm these findings.

Mesenchymal stem cells regulate epithelial–mesenchymal transition and tumor progression of pancreatic cancer cells

Cancer‐associated fibroblasts contribute to cancer progression that is caused by epithelial–mesenchymal transition (EMT). Recently, mesenchymal stem cells (MSCs) were found to be the major candidate involved in the development of tumor‐promoting cancer stroma. Here we report that α‐smooth muscle actin‐positive myofibroblast‐like cells originating from MSCs contribute to inducing EMT in side population cells of pancreatic cancer. More importantly, MSC‐derived myofibroblasts function to maintain tumor‐initiating stem cell‐like characteristics, including augmenting expression levels of various stemness‐associated genes, enhancing sphere‐ forming activity, promoting tumor formation in a mouse xenograft model, and showing resistance to anticancer drugs. Furthermore, both γ‐secretase inhibitor and siRNA directed against Jagged‐1 attenuated MSC‐associated E‐cadherin suppression and sphere formation in pancreatic cancer side population cells. Thus, our results suggest that MSC‐derived myofibroblasts play important roles in regulating EMT and tumor‐initiating stem cell‐like properties of pancreatic cancer cells through an intermediating Notch signal.

Measurement of colonic mucosal concentrations of 5-aminosalicylic acid is useful for estimating its therapeutic efficacy in distal ulcerative colitis: comparison of orally administered mesalamine and sulfasalazine.

ObjectivesOral 5-aminosalicylic acid (5-ASA) preparations have been used frequently in the treatment of ulcerative colitis. However, there have been few reports investigating the relationship between colonic mucosal concentrations of 5-ASA and its clinical efficacy when oral sulfasalazine or 5-ASA compounds were administered. The aim of this study is to compare the mucosal concentrations of 5-ASA ensured by sulfasalazine or mesalamine, and to define the clinical significance of the measurement of 5-ASA concentrations in the treatment of distal ulcerative colitis. Materials and MethodsBiopsies were taken from the rectum and sigmoid colon of the oral sulfasalazine group (n = 13) and the slow-release 5-ASA (mesalamine) group with (n = 5) or without (n = 11) rectal administration of 5-ASA. High-pressure liquid chromatography was used to measure the tissue concentrations of 5-ASA and its metabolites. We compared the 5-ASA concentrations of the sulfasalazine group with the mesalamine group. Furthermore, we analyzed the relationship between tissue 5-ASA concentrations and the Disease Activity Index (DAI). ResultsThe concentrations of 5-ASA and acetyl-5-ASA in the sulfasalazine group were higher than those in the group taking oral mesalamine alone (p < 0.01). The concentration of 5-ASA was much higher in the patients who received oral and rectal mesalamine in an enema than in the patients who had oral mesalamine alone. There was a significant inverse correlation between the DAI and concentrations of 5-ASA in the rectum (r = 0.712, p < 0.001). ConclusionsWe demonstrated that the colonic mucosal concentration of 5-ASA was significantly higher in the sulfasalazine group than in the mesalamine group. Furthermore, the concentrations of mucosal 5-ASA may be a good marker for the estimation of its efficacy in the treatment of ulcerative colitis.

The intestine-specific transcription factor Cdx2 inhibits β-catenin/TCF transcriptional activity by disrupting the β-catenin–TCF protein complex

Cdx2 is an intestine-specific transcription factor known to regulate proliferation and differentiation. We have reported previously that Cdx2 limits the proliferation of human colon cancer cells by inhibiting the transcriptional activity of the beta-catenin-T-cell factor (TCF) bipartite complex. Herein we further elucidate this mechanism. Studies with a classic Cdx2 target gene and a canonical Wnt/beta-catenin/TCF reporter suggest that Cdx2 regulates these promoters by distinctly different processes. Specifically, inhibition of beta-catenin/TCF activity by Cdx2 does not require Cdx2 transcriptional activity. Instead, Cdx2 binds beta-catenin and disrupts its interaction with the DNA-binding TCF factors, thereby silencing beta-catenin/TCF target gene expression. Using Cdx2 mutants, we map the Cdx2 domains required for the inhibition of beta-catenin/TCF activity. We identify a subdomain in the N-terminus that is highly conserved and when mutated significantly reduces Cdx2 inhibition of beta-catenin/TCF transcriptional activity. Mutation of this subdomain also abrogates Cdx2s anti-proliferative effects in colon cancer cells. In summary, we conclude that Cdx2 binds beta-catenin and disrupts the beta-catenin-TCF complex. Considering the pivotal role of beta-catenin/TCF activity in driving proliferation of normal intestinal epithelial and colon cancer cells, our findings suggest a novel mechanism for Cdx2-mediated regulation of Wnt/beta-catenin signaling and cell proliferation.

Suppression of myeloid cell leukemia-1 (Mcl-1) enhances chemotherapy-associated apoptosis in gastric cancer cells.

BackgroundMyeloid cell leukemia-1 (Mcl-1) is an anti-apoptotic protein that regulates apoptosis sensitivity in a variety of cell types. Here we evaluate the roles of Mcl-1 in chemotherapy-associated apoptosis in gastric cancer cells. In addition, our study examined whether Mcl-1 contributed to apoptosis resistance in so-called cancer stem cell (CSC)-like populations in gastric cancer.MethodsSeven gastric cancer cell lines were used. The expression of Mcl-1 was assessed by either real-time polymerase chain reaction or Western blot analysis. Apoptosis was quantitated by morphological observation and caspase activity measurement. Adenovirus-mediated RNA interference (RNAi) technology was used to knockdown the expression of Mcl-1. The release of cytochrome c was evaluated by subcellular fractionation and immunoblot analysis. To identify and isolate the CSC-like populations, we used the CSC-associated cell surface marker CD44 and flow cytometry.ResultsSix out of the 7 gastric cancer cell lines overexpressed Mcl-1 protein. These Mcl-1-expressing cell lines were relatively resistant to chemotherapeutic agents such as 5-fluorouracil (5-FU) and cisplatin (CDDP). Depletion of Mcl-1 protein by RNAi technology effectively sensitized the cells to anticancer drug-induced mitochondrial cytochrome c release, caspase activation, and apoptosis. In addition, vast amounts of Mcl-1 mRNA were expressed in CD44-positive CSC-like cells. Mcl-1 suppression enhanced the apoptosis in CD44-positive cells to a level equivalent to that in CD44-negative cells, suggesting that Mcl-1 mediates chemotherapy resistance in CSC-like populations.ConclusionThese results suggest that Mcl-1 mediates the resistance to apoptosis in gastric cancer cells by blocking the mitochondrial pathway of cell death. Mcl-1 depletion appears to be an attractive strategy to overcome chemotherapy resistance in gastric cancer cells.

Cdx2 Levels Modulate Intestinal Epithelium Maturity and Paneth Cell Development

BACKGROUND & AIMS Caudal-related homeobox protein 2 (Cdx2) is an intestine-specific transcription factor that is important for intestinal development and intestine-specific gene expression. Cdx2 regulates intestinal cell-cell adhesion, proliferation, and the transcriptional activities of Wnt and β-catenin in cell culture systems. We generated transgenic mice that overexpress Cdx2 in the small intestinal and colonic epithelium to investigate the role of Cdx2 in differentiation and function of the intestinal epithelium. METHODS We established 4 different lines of villin-Cdx2 transgenic mice. Intestines were collected from infant, 3-month old, and wild-type mice. Genes of interest and cell lineage markers were examined by polymerase chain reaction and immunohistochemistry. RESULTS Villin-Cdx2 transgenic mice had complex phenotypes that were associated with transgene expression levels. The 2 lines that had the greatest levels of transgene expression had significant, preweaning failure to grow and death; these were the result of early epithelial maturation and alterations in nutrient digestion and absorption. Fat malabsorption was a prominent feature. Other effects associated with the transgene expression included loss of Paneth cell markers, increases in goblet cells, and migration of proliferating, EphB2-expressing cells to the crypt base. Loss of Paneth cell markers was associated with reduced nuclear localization of β-catenin but not homeotic posteriorization of the epithelium by Cdx2. CONCLUSIONS Overexpression of Cdx2 in the small intestine is associated with reduced post-natal growth, early epithelial maturation, alterations in crypt base organization, and changes in Paneth and goblet cell lineages. Cdx2 is a critical regulator not only of intestine-specific genes, but also processes that determine epithelial maturity and function.

Rho modulates hepatic sinusoidal endothelial fenestrae via regulation of the actin cytoskeleton in rat endothelial cells

The presence of actin-like microfilaments in the vicinity of sinusoidal endothelial fenestrae (SEF) indicates that the cytoskeleton of sinusoidal endothelial cells (SEC) plays an important role in the modulation of SEF. Rho has emerged as an important regulator of the actin cytoskeleton, and consequently cell morphology. The present study aimed to examine how a Rho stimulator; lysophosphatidic acid (LPA), and a Rho inhibitor; bacterial toxin C3 transferase (C3-transferase), affect the morphology of SEF. Monolayers of SEC culture were established by infusing a rat liver with collagenase for 30 min and then culturing in RMPI medium for 24 h. The cells were separated into three groups; control, LPA-treated (15 μM), and C3-transferase-treated (15 μg/ml) groups. SEF morphology was observed by scanning electron microscopy. Formation of F-actin stress fibers was observed by confocal microscopy. Rho A and phosphorylated myosin light-chain kinase were analyzed by Western blotting. Active Rho was measured by Rens modification. Treatment of SECs with LPA contracted the SEF, concomitant with increases in F-actin stress fiber and actin microfilament, and high expression of phosphorylated myosin light-chain kinase. Following treatment with C3-transferase, SEF dilated and fused, concomitant with a loss of F-actin and microfilament, and low expression of phosphorylated myosin light chain. Rho A expression does not change by both treatments. In conclusion, these results indicate that Rho modulates fenestral changes in SEC via regulation of the actin cytoskeleton.

Repression of the Desmocollin 2 Gene Expression in Human Colon Cancer Cells Is Relieved by the Homeodomain Transcription Factors Cdx1 and Cdx2

Desmosomes are intracellular junctions that provide strong cell-cell adhesion in epithelia and cardiac muscle. Their disruption causes several human diseases and contributes to the epithelial-to-mesenchymal transition observed in cancer. Desmocollin 2 (DSC2) is a cadherin superfamily member and a critical component of desmosomes found in intestinal epithelium. However, the mechanism regulating DSC2 gene expression in intestinal cells is not known. Cdx1 and Cdx2 are homeodomain transcription factors that regulate intestine-specific gene expression. Cdx expression in the past has been associated with the induction of desmosomes. We now show that the DSC2 gene is a transcriptional target for Cdx1 and Cdx2. Colon cancer cell lines retaining Cdx2 expression typically express DSC2. Restoration of Cdx expression in Colo 205 cells induced DSC2 mRNA and protein and the formation of desmosomes. The 5′-flanking region of the DSC2 promoter contains two consensus Cdx-binding sites. Electrophoretic mobility shift assays show that Cdx1 and Cdx2 bind these sites in vitro, and chromatin immunoprecipitation confirmed Cdx2 binding in vivo. DSC2 promoter truncations established that these regions are Cdx responsive. The truncations also identify a region of the promoter in which potent transcriptional repressors act. This repressor activity is relieved by Cdx binding. We conclude that the homeodomain transcription factors Cdx1 and Cdx2 regulate DSC2 gene expression in intestinal epithelia by reversing the actions of a transcriptional repressor. The regulation of desmosomal junctions by Cdx contributes to normal intestinal epithelial columnar morphology and likely antagonizes the epithelial-to-mesenchymal transition necessary for the metastasis of colon cancer cells in humans. (Mol Cancer Res 2008;6(9):1478–90)

Lower doses of 6-mercaptopurine/azathioprine bring enough clinical efficacy and therapeutic concentration of erythrocyte 6-mercaptopurine metabolite in Japanese IBD patients.

Background: Although 6-mercaptopurine (6-MP) and azathioprine (AZA) are prescribed at lower doses, their efficacy in patients with inflammatory bowel disease (IBD) in Japan is comparable to that in Europe/America. However, there has been no report concerning the measurement of erythrocyte 6-thioguanine nucleotides (6-TGN), which is an active metabolite of 6-MP or AZA, in Japanese IBD patients. This study was designed to elucidate the pharmacokinetic–pharmacodynamic properties of 6-MP and AZA in Japanese patients by measurement of erythrocyte 6-TGN level. Methods: 134 adult patients (99 males; 35 females) with IBD (75 ulcerative colitis; 59 Crohns disease) who had been receiving a constant dose of 6-MP or AZA for three months or longer were enrolled. Erythrocyte 6-TGN levels were measured using the low-pressure gradient HPLC method, and correlated with treatment efficacy. The genetic polymorphism of thiopurine methyltransferase (TPMT) genotype was also assessed. Results: The mean erythrocyte 6-TGN level (mean ± SD) was 342.3 ± 220.9 pmol/8 × 108RBC, which was supposed to be therapeutic concentration, although the mean daily doses of 6-MP and AZA were no more than 29.8 ± 9.9 mg/day of 6-MP equivalent. However, all patients were identified with the wild type of TPMT genotype. There was no significant difference in the mean 6-TGN levels between patients in remission and no-remission group. The mean 6-TGN level was significantly higher in the once-daily administration group than three times-daily group. Conclusion: Thirty mg/day of 6-MP or 50 mg/day of AZA, once-daily oral administration in Japanese IBD patients was sufficient to achieve the therapeutic target level of 6-TGN in Europeans/Americans.

A case of Behçet’s disease accompanied by colitis with longitudinal ulcers and granuloma

A 37‐year‐old female presenting with oral and genital ulcers and erythema nodosum on both arms was diagnosed as having Behçet’s disease. The symptoms resolved spontaneously. However, she was admitted to our hospital (Keio University Hospital) several months later because of fever, aphthous ulcers of the oral cavity, lower abdominal pain and frequent diarrhea. A colonoscopic examination revealed multiple ulcers including longitudinal ulcers in the ascending and transverse colon, and histological examination of biopsied specimens demonstrated non‐caseating epithelioid granuloma. Treatment with prednisolone and 5‐aminosalicylic acid was started, and the patient responded well clinically. One month later, a repeated colonoscopy confirmed that the lesions including longitudinal ulcers had disappeared. In this report, we describe our experience of this rare case of Behçet’s disease concomitant with colonic longitudinal ulcers and epithelioid granuloma, and discuss the difficulties in making a differential diagnosis, primarily with regard to Crohn’s disease.