Antimicrobial peptides are major effectors of innate immunity of multicellular organisms including humans and play a critical role in host defense, and their importance is widely recognized. The epithelium of the intestine is the largest surface area exposed to the outer environment, including pathogens, toxins and foods. The Paneth cell lineage of intestinal epithelial cells produces and secretes α-defensin antimicrobial peptides and functions in innate enteric immunity by removing pathogens and living symbiotically with commensal microbiota to contribute to intestinal homeostasis. Paneth cells secrete α-defensins, HD5 and HD6 in humans and cryptdins in mice, in response to bacterial, cholinergic and other stimuli. The α-defensins have selective activities against bacteria, eliciting potent microbicidal activities against pathogenic bacteria but minimal or no bactericidal activity against commensal bacteria. Therefore, α-defensins regulate the composition of the intestinal microbiota in vivo and play a role in homeostasis of the entire intestine. Recently, relationships between dysbiosis, or abnormal composition of the intestinal microbiota, and diseases such as inflammatory bowel disease and lifestyle diseases including obesity and atherosclerosis have been reported. Because α-defensins regulate the composition of the intestinal microbiota, Paneth cells and their α-defensins may have a key role as one mechanism linking the microbiota and disease.

Paneth cells at the base of small intestinal crypts secrete -defensins, which contribute to innate immunity and shape composition of enteric microbiota. Efforts to establish relationship between secreted -defensins and disease have been hampered by a lack of sensitive assays to quantify luminal -defensins. Here we report on a highly sensitive sandwich enzyme-linked immunosorbent assay (ELISA) for the mouse Paneth cell -defensin cryptdin-4 (Crp4) in varied sources, including luminal contents rinsed from stomach to distal colon, as well as fecal pellets. One pair of monoclonal antibodies (mAbs), selected from 10 rat hybridomas secreting Crp4-specific mAbs, was optimized for Crp4 detection and specificity in the sandwich ELISA. In CD1 mice, luminal Crp4 levels gradually increased from 6.8 ± 5.2 ng/ml in proximal to 54.3 ± 10.3 ng/ml in distal small intestine, and the peptide was detected in colonic lumen and feces. Secreted Crp4 was reduced significantly in feces of IL10-null mice, a model of inflammatory bowel disease (IBD) when compared with wild-type controls. This Crp4 sandwich ELISA enable accurate determinations of luminal -defensins as biomarkers of Paneth cell function and enteric integrity in diverse disease states such as IBD, infectious disease, graft-versus-host-disease, and obesity in association with dysbiosis of the intestinal microbiota.

The incidence of endometrial cancer and ovarian cancer in Japan has been increasing in recent years. Results of epidemiologic studies suggest that the onset and multiplication of these cancers are associated with estrogen. Estrogens are metabolized by cytochrome P450 1A1 (CYP1A1) and converted into catecholestrogens, which are carcinogens. CYP1A1 has several polymorphisms, the major one being T6235C transition in the non-coding 3′-flanking region (MspI polymorphism), and another being A4889G transition in exon 7 (Ile/Val polymorphism). These polymorphisms can affect the metabolites of estrogens and contribute to the susceptibility to gynecological malignancy. In this study, to determine whether CYP1A1 polymorphism plays a role in the development of gynecological malignancy in the Japanese population, we assessed the association of CYP1A1 polymorphism in Japanese patients with gynecological malignancy in comparison to that in controls. The odds ratios (ORs) of Ile/Val polymorphism were 1.16 in ovarian cancer patients and 1.70 in endometrial cancer patients. The ORs of MspI polymorphism were 1.33 in ovarian cancer patients and 0.88 in endometrial cancer patients. No significant association was found between these CYP1A1 polymorphisms and gynecological malignancy. Although the frequency of CYP1A1 polymorphism in the Japanese population is higher than that in the Caucasian population, CYP1A1 polymorphism is not related to gynecological malignancies in Japanese population.

Purpose: The interleukin-13 receptor a2 (IL-13Ra2) is expressed by a variety of human malignant cells. Here, we have examined the constitutive surface expression and the epigenetic regulation of IL-13Ra2 by human mesothelioma. We have also investigated the therapeutic effect of the DNA methylation inhibitor 5-aza-2 0 -deoxycytidine (5-aza-dC) and anti-IL-13Ra2 monoclonal antibody on mesothelioma xenografts.Experimental Design: Cell surface expression of IL-13Ra2 by various lung carcinomas was analyzed using flow cytometry. Therapeutic effects of anti-IL-13Ra2 and 5-aza-dC were investigated using antibodydependent cellular cytotoxicity and proliferation assays and by monitoring the survival of mesotheliomabearing mice.Results: We found that human malignant mesotheliomas expressed surface IL-13Ra2 on their surface and that it was upregulated by treatment with 5-aza-dC. This augmented expression of IL-13Ra2 resulted in growth inhibition of the mesothelioma cells when cocultured with anti-IL-13Ra2 and effector cells, such as splenocytes and peritoneal exudate cells. The growth inhibition of mesothelioma cells was mediated by IFN-g that was only detected in the supernatant when effector cells were exposed to 5-aza-dC-treated tumors in the presence of anti-IL-13Ra2. Compared with the control or either regimen alone, in vivo administration of anti-IL-13Ra2 in combination with 5-aza-dC significantly prolonged the survival of mice with mesothelioma xenografts.Conclusions: These observations indicate a promising role for IL-13Ra2 as a target for antibody treatment in malignant mesothelioma, and, in combination with epigenetic regulation by a DNA methylation inhibitor, suggest the potential for a novel strategy to enhance therapeutic potency.

These data suggest that CD13 is a suitable cell surface candidate for targeted antibody-drug therapy of scirrhous gastric cancer.