The role of the peyer's patch in the carcinogenesis of lymphoid cells

Abstract

The dose response to 3-methylcholanthrene (3-MC), the promoter effects of 2,6,10,14-tetramethylpentadecane (pristane) and the target-organ specificity in the preferential induction of B-lymphoid malignancies versus thymic tumors were examined. Lymphoid malignancies were induced in approximately 30% of the Copenhagen rats treated with injections in Peyer's patches (PP) of low, intermediate or high doses of 3-MC. A low dose of 3-MC induced B-lymphocytic leukemias or B lymphomas, whereas thymic tumors were detected in rats treated with high doses. Co-treatment of rats with pristane and 3-MC resulted in increased incidences and decreased latency of the lymphoid malignancies observed, suggesting that pristane acts as a tumor promoter. To address the possible role of PP in the induction events, PP were surgically removed after 3-MC treatment and the remaining small intestine anastomosed. Thymic tumors, but no B-lymphoid malignancies, were observed, indicating that the PP environment was important in the induction of the B-lymphoid malignancies. Radiotracer studies also revealed that appreciable amounts of 3-MC were disseminated to the thymus within 24 hr after treatment of PP with a high dose of 3-MC. Furthermore, direct intrathymic injection of the thymus with 3-MC resulted in the development of thymic tumors only. These results support the hypothesis that the PP has an important role in early events in the carcinogenesis of B lymphocytes and in the dissemination of 3-MC to the thymus.

Pristane induced effects on chromatin of rat lymphoid cells

“…Studies to address the possible basis for the pristane-induced changes in the DNA staining characteristics of lymphocytes demonstrated that 1 ) there were no decreases in the amount of DNA present in the nuclei, 2) nuclei isolated from pristane treated rats were less sensitive to thermal denaturation, as well as DNase I enzymatic digestion, and 3) there were apparent increases in the expression of the HI histone proteins. Collectively, these results suggest that pristane elicits a conformational change in the chromatin which may be mediated by altered expression of nuclear-associated histone proteins.Key words: 2,6,10,14-tetramethylpentadecane, histone, DNA conformation, pristane, lymphocyte Pristane also elicits a promoter-like response in that treatment with 3-methylcholanthrene (3-MC) resulted in few lymphoid malignancies, whereas treatment with 3-MC and pristane resulted in the induction of lymphoid leukemias and lymphomas in > 60% of the rats examined [11][12][13]. Furthermore, while the above mentioned biological effects of pristane suggest that Lenora R. Garrett's current address is Tumor Biology, Fred…”

“…Pristane also elicits a promoter-like response in that treatment with 3-methylcholanthrene (3-MC) resulted in few lymphoid malignancies, whereas treatment with 3-MC and pristane resulted in the induction of lymphoid leukemias and lymphomas in > 60% of the rats examined [11][12][13]. Furthermore, while the above mentioned biological effects of pristane suggest that pristane may act indirectly to elicit the corresponding effects, previous studies in our laboratory indicate that pristane may have a more direct effect on the cellular DNA.…”