It has been found that incubation of UDP-galactose with GTP, Mn ions and extracts of transformed cells results in the formation of several rapidly migrating products. Two of these products are dominant, """"""""Fast Peak 2"""""""" (FP2) and """"""""Fast Peak 4"""""""" (FP4). The reaction is catalyzed by extracts of transformed cells with mutated or elevated levels of ras oncogene product (K-ras, H-ras and N-ras). Activity is also seen in human tumor cell lines (breast, lung, bladder), SV40-transformed cells and chemically transformed liver cells. The reaction is not detected in a variety of control cells, polyoma and Rous virus-transformed cells and some malignant cells. Preliminary experiments indicate that the reaction catalyzed by an extract of KMSV-transformed mouse fibroblasts can be inhibited by an anti-ras monoclonal antibody.
Our aim i s to: (a) obtain sufficient material to establish the structures of FP2 and FP4; (b) study their effects on cells and reactions related to growth control in order to establish their role in malignant (and normal) cells, i.e., whether the FP derivatives are involved in normal control of growth and differentiation; (c) fractionate the enzymes and factors involved in the synthesis of FP; (d) determine the nature of the reaction and the metabolic relation of FP2 and FP4; (e) establish that the ras gene product is a part of the mechanism and determine the action of the ras protein in normal and malignant cells; and (f) determine the distribution of the FP synthesizing enzymes in control and malignant tissues. We also plan to complete our studies in progress on: 1) the degradation of CMPNAN to form a putative CMPpyruvate. 2) comparison of glycopeptides of control and transformed cells. 3) the influence of environment and drugs on the carbohydrate component of IgG produced by hybridomas and the consequences of altered carbohydrate structure.
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