Anti-FUT4 monoclonal antibody, clone 2.CC.331 [PE]

We report that the overexpression of mitochondrial ribosomal protein MRPS18-2 (S18-2) can immortalize primary rat embryonic fibroblasts (REFs). The immortalized cells (18IM) lose contact inhibition, form foci, and are capable of anchorage-independent growth. Concurrently, mesodermal markers, such as vimentin, smooth muscle actin, and Fut4, disappear completely. 18IM cells express embryonic stem cell markers, such as SSEA-1, Sox2, and Oct3/4. In confluent cultures, a portion of cells also express ectodermand endoderm-specific pan-keratin, ectoderm-specific beta-III-tubulin, mesoderm-specific MHC class II, and become stainable for fat with Oil red O. None of these changes was detected in c-myc+Ha-ras (MR)-transformed cells. In immunodeficient mice, 18IM cells formed small transiently growing tumors that have down-regulated SSEA-1 and showed pan-keratin staining. We conclude that S18-2 can immortalize REFs and induces them to express stem cell traits.

Protein glycosylation is an important posttranslational process, which regulates protein folding and functional expression. Studies have shown that abnormal glycosylation in tumor cells affects cancer progression and malignancy. In the current study, we have identified sialylated proteins using an alkynyl sugar probe in two different lung cancer cell lines, CL1-0 and CL1-5 with distinct invasiveness derived from the same parental cell line. Among the identified sialylated proteins, epidermal growth factor receptor (EGFR) was chosen to understand the effect of sialylation on its function. We have determined the differences in glycan sequences of EGFR in both cells and observed higher sialylation and fucosylation of EGFR in CL1-5 than in CL1-0. Further study suggested that overexpression of sialyltransferases in CL1-5 and alpha 1,3-fucosyltransferases (FUT4 or FUT6) in CL1-5 and A549 cells would suppress EGFR dimerization and phosphorylation upon EGF treatment, as compared to the control and CL1-0 cells. Such modulating effects on EGFR dimerization were further confirmed by sialidase or fucosidase treatment. Thus, increasing sialylation and fucosylation could attenuate EGFR-mediated invasion of lung cancer cells. However, incorporation of the core fucose by alpha 1,6-fucosylatransferase (FUT8) would promote EGFR dimerization and phosphorylation.