Modulation of intracellular biomarkers by dietary fat and fiber in colon carcinogenesis /
Protein kinase C plays an important role in colonic cell proliferation and differentiation. The profile of PKC in rat colon was defined in this study. PKC (x, 8 and C mRNAs were expressed along the entire colonic crypt axis as determined by in situ RTPCR. However, immunohistochemical analysis rev...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=743273301&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Protein kinase C plays an important role in colonic cell proliferation and differentiation. The profile of PKC in rat colon was defined in this study. PKC (x, 8 and C mRNAs were expressed along the entire colonic crypt axis as determined by in situ RTPCR. However, immunohistochemical analysis revealed that isozyme protein expression was greater at the top of the crypt. The effect of specific types of dietary fats (corn oil and fish oil) and fibers (cellulose and pectin) on PKC related mediators in rat colon carcinogenesis was examined. K-ras mutations were detected as early as 15 wk post-AOM injection. No K-ras mutations were detected in colonic mucosa from saline-injected animals. Dietary fish oil delayed the onset of K-ras mutations. In addition, at 15 wks, AOM treated animals fed corn oil diets had significantly (p<0.001) higher DAG mass and PLC-yl expression compared to AOM-injected animals fed fish oil and saline-injected rats on all diets. In contrast, dietary fiber had no effect on any of the parameters measured at this time. However, at 37 wks, cellulose-containing diets had significantly (p<0.02) higher DAG mass, PLC-yl expression and DAG/ceramide ratio than animals fed pectin diets. Protein and MRNA expression of major colonic PKC isozymes, (X, 5 and C indicated that AOM injection significantly decreased PKC a and C protein levels. In contrast, rats fed fish oil diets had significantly higher (P<0.05) PKC 8 and C protein levels than animals fed corn oil diets. Similarly, pectin significantly (P<0.05) enhanced cytosolic PKC C protein levels in comparison to cellulose diets. However, PKC isozyme mRNAs were not consistent with changes in the respective isozyme protein levels. These data demonstrate that dietary fats and fibers may modulate colon carcinogenesis in a time dependent manner, with fat modulating colonic intracellular mediators at early stages and fiber exerting an effect at later stages of colon carcinogenesis. Specific dietary fats and fibers may alter colon cancer incidence through their effects on PKC related signaling systems in the colon. |
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| Item Description: | Vita. "Major Subject: Nutrition". |
| Physical Description: | xiv, 199 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |