Sialyltransferase of the 13762 Rat Mammary Ascites Tumor
نویسندگان
چکیده
When compared to normal esophageal epithelium, marked alterations in keratin protein and cross-linked envelope expres sion were found in human esophageal carcinomas. Examination of the pattern of keratin proteins extracted from either several primary esophageal tumors or carcinomas xenotransplanted in nude mice revealed a dramatic reduction in the amount of keratin protein, especially in the Mr 52,000 to 61,000 range. In seven of eight of the primary tumors, the major M, 52,000 and M, 61,000 esophageal keratins were not detected, and the remaining tumor exhibited a marked reduction in these two keratins. The major M, 57,000 and minor M, 59,000 esophageal keratins were found in varying but reduced amounts in the different tumors. The major M, 57,000 keratin seemed to be the most conserved keratin of this intermediate-molecular-weight keratin class (M, 52,000 to 61,000). In contrast, the lower-molecular-weight ker atins (M, 46,000 to 50,500) were usually conserved in the carci noma cells and were present at levels approximating that of the nontransformed counterpart. The minor Mr 37,000 and 44,000 keratins from normal esophageal epithelium were retained in the tumor cells but often in reduced amounts. The expression of another differentiated function, cross-linked envelopes, in the carcinoma cells varied from unimpaired to severely restricted capacity to form envelopes. In conclusion, specific alterations in keratin protein and crosslinked envelope expression were found in human esophageal carcinomas.
منابع مشابه
Sialyltransferase of the 13762 rat mammary ascites tumor cells.
The MAT-B1 and MAT-C1 ascites sublines of the 13762 rat mammary adenocarcinoma differ in morphology, agglutinability with concanavalin A, and xenotransplantability. Both cell lines contain a major mucin-type glycoprotein, but the MAT-C1 (xenotransplantable) subline contains a 3-fold-greater content of sialic acid on the glycoprotein than does the MAT-B1 (nonxenotransplantable) subline. The pres...
متن کاملPost-transcriptional regulation of a milk membrane protein, the sialomucin complex (Ascites sialoglycoprotein (ASGP)-1/ASGP-2, rat muc4), by transforming growth factor beta.
Sialomucin complex (SMC, Rat Muc4) is a heterodimeric glycoprotein complex consisting of a mucin subunit ASGP-1 (ascites sialoglycoprotein-1) and a transmembrane subunit ASGP-2, which can act as a ligand for the receptor tyrosine kinase ErbB2. SMC is highly expressed on the surface of ascites 13762 rat mammary adenocarcinoma cells, approximately 100 times the level in lactating mammary gland an...
متن کاملCell surface sialomucin and resistance to natural cell-mediated cytotoxicity of rat mammary tumor ascites cells.
MAT-B1 and MAT-C1 ascites sublines of the 13762 rat mammary adenocarcinoma both contain sialomucin as a major cell surface component and are resistant to cytolysis by normal rat spleen lymphocytes [3 +/- 2% (SD) and 0 +/- 1%, respectively]. Susceptibility to lysis did not increase following treatment of cells with neuraminidase, fucosidase, or alpha- or beta-galactosidase. Treatment with trypsi...
متن کاملCell Surface Sialomucin and Resistance to Natural Cell-mediated Cytotoxicity of Rat Mammary Tumor Ascites Cells1
MAT-B1 and M A I -( 1 ascites subîmes of the 13762 rat mammary adenocarcinoma both contain sialomucin as a major cell surface compo nent and are resistant to cytolysis by normal rat spleen lymphocytes |3 ±2% (SD) and O ±1%, respectively). Susceptibility to lysis did not increase following treatment of cells with neuraminidase, fucosidase, or aor 0-galactosidase. Treatment with trypsin signif...
متن کاملCirculating Immune Complexes in Rats Bearing 6-Thioguanine-resistant Variants of the 13762 Mammary Adenocarcinoma1
The relationship between immune complex (1C)formation and tumor cell metastatic potential was investigated in rats inoculated in the footpad with parental 13762 mammary adenocarcinoma cells or 6-thioguanine-resistant (TGR) variant cells. These cell lines are either highly metastatic (13762), nonmetastatic (TGR), or occasionally metastatic (TGRrev, TGRrevM). The 13762 TGR rat tumor model thus pr...
متن کاملCirculating immune complexes in rats bearing 6-thioguanine-resistant variants of the 13762 mammary adenocarcinoma.
The relationship between immune complex (IC) formation and tumor cell metastatic potential was investigated in rats inoculated in the footpad with parental 13762 mammary adenocarcinoma cells or 6-thioguanine-resistant (TGR) variant cells. These cell lines are either highly metastatic (13762), nonmetastatic (TGR), or occasionally metastatic ( TGRrev , TGRrevM ). The 13762 TGR rat tumor model thu...
متن کامل