Sialyl Lewis x and sialyl Lewis a are oncodevelopmental antigens involved in the pathogenesis of colon adenocarcinoma. Biosynthesis of these glycans is controlled by alpha(1,3/1,4)fucosyltransferases. We report the disruption of sialyl Lewis x/a biosynthesis and inhibition of colon carcinoma cell proliferation by stable transfection of antisense sequences directed at the human Lewis alpha(1,3/1,4)fucosyltransferase gene, FUT3, and the plasma alpha(1,3)fucosyltransferase gene, FUT6. COLO-205 cells expressed high levels of sialyl Lewis x/a, alpha(1,3)fucosyltransferase activity, and FUT3/6 transcripts, but COLO

The study of immortalization and other alterations associated with neoplastic transformation of endometrial stromal cells is important to understanding the development of uterine sarcomas and mixed tumors. Because stromal cells are important regulators of associated epithelial cells, alterations in the regulation of stromal cell proliferation that influence epithelial cells may also contribute to the development of endometrial carcinomas. To study immortalization and associated phenotypic and genetic alterations of human endometrial stromal cells, cultures were transfected with a plasmid containing an ori-, temperature-sensitive mutant SV40, A209 (tsSV40). Morphologically transformed colonies were selected and propagated at the permissive temperature until they entered 'crisis'. In contrast to human fibroblasts, every clone tested was immortalization competent. The frequency of immortalization was approximately 1 x 10(-6). One uncloned and six cloned cell lines escaped from crisis and appear to be immortal. Two clones, M4 and B10T1, were selected for further study. Immortalization is conditional; proliferative arrest occurs at the restrictive temperature for large T antigen function. Furthermore, withdrawal of the large T antigen results in expression of the senescent phenotype of enlarged, flattened cells. Colony-forming efficiency at the restrictive temperature was undetectable. Immortalization is also associated with several genetic alterations. The DNA content of tsSV40 transfected cells was either diploid or tetraploid in the precrisis stage of proliferation, but became aneuploid upon immortalization. Several structural rearrangements of chromosomes were detected in the immortalized stromal cells which differ from those found in SV40 immortalized fibroblasts. Although their capacity for anchorage-independent proliferation (AIP) is variable, tsSV40-immortalized endometrial stromal cells have a higher capacity for AIP than their tsSV40-transfected progenitor cells in the period of proliferation prior to 'crisis'.

The normal genomic stability of human cells is reversed during neoplastic transformation. The SV40 large T antigen alters the DNA content in human endometrial stromal cells in a manner that relates to neoplastic progression. Human endometrial stromal cells were transfected with a plasmid containing the A209 temperature-sensitive mutant of SV40 (tsSV40), which is also defective in the viral origin of replication. Ninety-seven clonal transfectants from seven different primary cell strains were isolated. Initial analysis revealed that 20% of the clonal populations (19/97) had an apparent diploid DNA content, 35% (34/97) had an apparent tetraploid DNA content, and the remainder were mixed populations of diploid and tetraploid cells. No aneuploid populations were observed. Diploid tsSV40 transformed cells always give rise to a population of cells with a tetraploid DNA content when continuously cultured at the permissive temperature. The doubling of DNA content can be vastly accelerated by the sudden reintroduction of large T antigen activity following a shift from non-permissive to permissive temperature. Tetraploid tsSV40 transfected cells have a lower capacity for anchorage-independent growth and earlier entry into 'crisis' than diploid cells. These results indicate that during the pre-crisis, extended lifespan phase of growth, the SV40 large T antigen causes a doubling of DNA content. This apparent doubling of DNA content does not confer growth advantage during the extended lifespan that precedes 'crisis'.

The initial steps of leukocyte adhesion depend on selectin/ligand interactions. Surface ligands on leukocytes are often modified by addition of the sialyl Lewis x (CD15s) determinant. Biosynthesis of CD15s is dependent upon α(2,3)sialyltransferases and α(1,3)fucosyltransferases. We report the isolation of an HL60 cell line variant, HL60A2, that no longer expresses CD15s. HL60A2 cells do not adhere to cytokine‐stimulated endothelial cells. Enzymatic assays reveal that this cell line has normal α(2,3)sialyltransferase activity but is deficient in the α(1,3)fucosyltransferase responsible for biosynthesis of CD15s (FUT7). The fucosyltransferase that constructs the non‐sialylated antigen, Lewis x (CD15), is expressed at high levels (FUT4). Transcript analyses show that FUT7 and FUT4 are inversely expressed in HL60 and variant cell lines. HL60A2 cells provide a tool to study the regulation of selectin ligands and corresponding human fucosyltransferase genes.

Sialyl Lewis x and sialyl Lewis a are oncodevelopmental antigens involved in the pathogenesis of colon adenocarcinoma. Biosynthesis of these glycans is controlled by alpha(1,3/1,4)fucosyltransferases. We report the disruption of sialyl Lewis x/a biosynthesis and inhibition of colon carcinoma cell proliferation by stable transfection of antisense sequences directed at the human Lewis alpha(1,3/1,4)fucosyltransferase gene, FUT3, and the plasma alpha(1,3)fucosyltransferase gene, FUT6. COLO-205 cells expressed high levels of sialyl Lewis x/a, alpha(1,3)fucosyltransferase activity, and FUT3/6 transcripts, but COLO