Non-invasive detection of protein kinase C Beta II and [], putative biomarkers for colon cancer using fecal messenger RNA
Date
1997
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Texas A&M University
Abstract
There is strong evidence that select dietary factors play a key role in the development of colon cancer. It has recently been shown that dietary fat and fiber can alter colonic protein kinase C (PKC) activity and isozyme expression, which may influence the malignant transformation process. The effect of diet on the expression of PKC [ ], and [ ]in fecal material was examined in this study. In addition, the effect of a carcinogen on PKC [ ],, and [ ] mRNA levels in feces was determined in order to develop non-invasive methodology to detect potential markers for colon cancer. Weanling rats were fed diets containing corn oil or fish oil, cellulose or pectin and injected twice at one-week intervals with saline or azoxymethane (AOM; 15 mg/kg body weight) in a 2 x 2 x 2 factorial design. Fresh fecal samples (n=6 per treatment) were collected 36 weeks after the second injection, poly A+ RNA was isolated and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) performed using primers specific for the regulatory subunit of PKC [ ], and [ ]. Fecal PKC mRNA isozyme expression was altered by the injection of carcinogen (p < 0.03), with AOM injected animals having 2.5-fold lower PKC @ expression compared to saline injected animals. Fecal PKC 01, mRNA expression was 3-fold higher in tumor bearing animals as compared to non-tumor bearing animals (p < 0.03). In addition, AOM injection increased mucosal PKC [ ] MRNA expression compared with saline controls. No main effect of tumor incidence on mucosal PKC [ ], expression was observed. Since tumor incidence exerts a reciprocal effect on fecal PKC [ ], and [ ]mMRNA expression, data were also expressed as a ratio between PKC [ ]and [ ]. The ratio of PKC [ ]was significantly higher in animals with tumors, 2.18 ︢1.25, as compared to animals without tumors, 0.50 ︢0.16 (p=0.025). We propose that expression of PKC [ ] and the ratio of [ ]in feces mayserve as non-invasive markers for colon carcinogenesis. A sensitive technique for thedetection of colon cancer is of importance since early diagnosis can substantially reduce mortality.
Description
Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.
Includes bibliographical references: p. 41-49.
Issued also on microfiche from Lange Micrographics.
Includes bibliographical references: p. 41-49.
Issued also on microfiche from Lange Micrographics.
Keywords
nutrition., Major nutrition.