Study protocol on the role of intestinal microbiota in colorectal cancer treatment: a pathway to personalized medicine 2.0.

PURPOSE: Investigate in patients with metastatic and/or irresectable colorectal cancer treated with systemic treatment with capecitabine or TAS-102 whether: 1. Intestinal microbiota composition can act as a predictor for response. 2. Intestinal microbiota composition changes during systemic treatment and its relation to chemotoxicity. BACKGROUND: Gut microbiota and host determinants evolve in symbiotic and dependent relationships resulting in a personal ecosystem. In vitro studies showed prolonged and increased response to 5-fluorouracil, a fluoropyrimidine, in the presence of a favorable microbiota composition. Capecitabine and TAS-102 are both fluoropyrimidines used for systemic treatment in colorectal cancer patients. METHODS: An explorative prospective multicenter cohort study in the Maastricht University Medical Centre+ and Zuyderland Medical Centre will be performed in 66 patients. Before, during, and after three cycles of systemic treatment with capecitabine or TAS-102, fecal samples and questionnaires (concerning compliance and chemotoxicity) will be collected. The response will be measured by CT/MRI using RECIST-criteria. Fecal microbiota composition will be analyzed with 16S rRNA next-generation sequencing. The absolute bacterial abundance will be assessed with quantitative polymerase chain reaction. Multivariate analysis will be used for statistical analysis. CONCLUSIONS: We aim to detect a microbiota composition that predicts if patients with metastatic and/or irresectable colorectal cancer will respond to systemic treatment and/or experience zero to limited chemotoxicity. If we are able to identify a favorable microbiota composition, fecal microbiota transplantation might be the low-burden alternative to chemotherapy switch in the future.

Regulation and characteristics of vascular smooth muscle cell phenotypic diversity.

Vascular smooth muscle cells can perform both contractile and synthetic functions, which are associated with and characterised by changes in morphology, proliferation and migration rates, and the expression of different marker proteins. The resulting phenotypic diversity of smooth muscle cells appears to be a function of innate genetic programmes and environmental cues, which include biochemical factors, extracellular matrix components, and physical factors such as stretch and shear stress. Because of the diversity among smooth muscle cells, blood vessels attain the flexibility that is necessary to perform efficiently under different physiological and pathological conditions. In this review, we discuss recent literature demonstrating the extent and nature of smooth muscle cell diversity in the vascular wall and address the factors that affect smooth muscle cell phenotype. (Neth Heart J 2007;15:100-8.).

Expression of the smoothelin gene is mediated by alternative promoters.

OBJECTIVE: Two major isoforms of smoothelin have been reported, a 59-kDa smoothelin-A in visceral smooth muscle cells and a 110-kDa smoothelin-B in vascular smooth muscle cells. The present study was undertaken to investigate the expression of these smoothelin isoforms in different smooth muscle tissues and to determine how they are generated. METHODS: Western blotting with a new, well-defined, smoothelin antibody was used to confirm the existence of two major smoothelin isoforms. Northern blotting, RT-PCR, primer extension and 5'RACE were applied to analyse the expression of these isoforms in human and mouse. Promoter reporter assays were carried out to establish the existence of a dual promoter system governing the expression pattern of the gene. RESULTS: Antibody C6G confirmed the existence of two smoothelin proteins. Northern blotting showed that in vascular tissues a larger smoothelin transcript is generated than in visceral tissue. The cDNA of this larger smoothelin-B was cloned. Computer analysis of the open reading frame suggests an alpha-helical structure of 130 amino acids at the amino terminus of smoothelin-B. The smoothelin gene was cloned and sequenced. It comprises about 25 kb and contains 21 exons. The translational start of smoothelin-B is located in exon 2, whereas transcription and translation of the previously described smoothelin-A starts inside exon 10. Smoothelin-A and -B were demonstrated to be generated by two physically separated promoters. Splice variants within the calponin homology domain at the 3' end of the gene were found for both isoforms. CONCLUSIONS: Two major smoothelin isoforms are generated from a single gene by a dual promoter system in a tissue specific manner. Further variation in the smoothelin proteins is achieved by alternative splicing in the calponin homology domain.