Robert Shores

Malignant conversion of mouse skin tumours is increased by tumour initiators and unaffected by tumour promoters.

Multi-stage carcinogenesis (initiation–promotion) was first demonstrated in mouse skin1,2. The first stage, initiation, is accomplished by a low dose of carcinogen that causes no tumours. Promotion by repeated treatment of initiated mice with certain non-carcinogenic hyperplastic agents results in the rapid production of numerous benign papillomas, a few of which progress to squamous cell carcinomas. Although this model system produces mostly benign tumours, many of the concepts concerning carcinogenesis in epithelial tissues have been derived from mouse skin studies. The permanent change in growth potential accomplished by tumour initiators is generally considered to be a mutagenic event3; cell selection and clonal expansion of initiated cells may be involved in promotion4. In initiation–promotion experiments, more than 90% of the squamous cell carcinomas develop from papillomas5,6, but the conversion rate is low. The factors necessary for this conversion of benign to malignant tumours have not been defined but tumour promoters have been assumed to be involved. However, we report here that the tumour promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA) is ineffective in the conversion of papillomas to carcinomas whereas three initiators, urethane, N-methyl-N′-nitro-N-nitrosoguanidine ((MNNG) and 4-nitroquinoline-N-oxide (4-NQO) are effective. This suggests that malignant conversion may result from a further genetic change in papilloma cells and that the ineffectiveness of TPA may be due to its inactivity as a mutagen.

Markers of Inflammation and Lineage on Exfoliated Colonic Cells In Pediatric Inflammatory Bowel Disease

OBJECTIVES The diagnosis (endoscopy, and biopsy) and continued clinical management of Inflammatory Bowel Disease (IBD), remain highly invasive, expensive, and inconvenient for the pediatric patient. The objective of this study was to see if colonocytes obtained from stools of subjects with IBD and normal controls would demonstrate higher levels of inflammatory markers (Cox 2 in CD45+ and CD45- cells) and if the inflammatory process and treatment effects would be reflected in an altered cytokine expression in the subjects compared to controls. SETTING Outpatient hospital based pediatric gastroenterology clinic. METHODS AND MAIN OUTCOME MEASURES Stool samples (~ 1 gm), were obtained from 18 children between the ages of 4 and 18 diagnosed with IBD, and from a normal first degree relative. Colonocytes were isolated using the Somatic Cell Sampling Recovery (SCSR) system and assessed for the expression of COX-2, CD-45, IgA, IgG, IL6, IL18, TGF β, TNF, and IL16β using flow cytometry. In addition, levels of COX-2 and cytokeratin 19 transcripts were measured by microwell plate hybridization assay. RESULTS Expression of COX-2 and co-expression of IgA and IgG were significantly higher in the IBD cases compared to the controls. In ulcerative colitis, the expression of COX-2 and co-expression of COX-2 and CD45 were greater than that in patients with Crohns disease. In contrast, cells expressing IgA and IgG were higher in Crohns. Subjects on immunosuppressants and/or anti-inflammatory medications, expressed significantly lower levels of COX-2 and IL-18 compared to those who were not on treatment. CONCLUSIONS This study indicates that the use of disease markers on exfoliated colonic cells can be used for non-invasive assessment of disease status, for follow-up of response to treatment and for forecasting flare-up of disease before its symptomatic manifestations.

Identification Of A Native Novel Oncolytic Immunoglobulin On Exfoliated Colon Epithelial Cells: A Bispecific Heterodimeric Chimera Of IgA/IgG

Understanding the nature of cell surface markers on exfoliated colonic cells is a crucial step in establishing criteria for a normally functioning mucosa. We have found that colonic cells isolated from stool samples (SCSR-010 Fecal Cell Isolation Kit, NonInvasive Technologies, Elkridge, MD), preserved at room temperature for up to one week, with viability of >85% and low levels of apoptosis (8% - 10%) exhibit two distinct cell size subpopulations, in the 2.5μM– 5.0 μM and 5.0μM-8.0μM range. In addition to IgA, about 60% of the cells expressed a novel heterodimeric IgA/IgG immunoglobulin that conferred a broad-spectrum cell mediated cytotoxicity against tumor cells. In a cohort of 58 subjects the exclusive absence of this immunoglobulin in two African-Americans was suggestive of a germline deletion. Serial cultures in stem cell medium retained the expression of this heterodimer. Since a majority of the cystic cells expressed the stem cell markers Lgr5 and Musashi-1 we termed these cells as gastrointestinal progenitor stem cells (GIP-C**). CXCR-4, the cytokine co-receptor for HIV was markedly expressed. These cells also expressed CD20, IgA, IgG, CD45, and COX-2. We assume that they originated from mature columnar epithelium by dedifferentiation. Our observations indicate that we have a robust noninvasive method to study mucosal pathophysiology and a direct method to create a database for applications in regenerative medicine.