Susceptibility of rat colon carcinoma cells to lymphokine activated killer-mediated cytotoxicity is decreased by alpha 1,2-fucosylation

The presence of alpha 1,2-fucosylated glycans at the surface of rat colon c arcinoma cells has been associated with an increased tumorigenicity and res istance to natural killer/lymphokine activated killer (NK/LAK) cytotoxicity , We now report that transfection of rat alpha 1,2-fucosyltransferases cDNA (FTA and FTB) into REC cells, which are spontaneously devoid of this enzym atic activity, allows expression of histo-blood group H antigen and increas es their resistance to LAK, but not NK cell lysis. Conversely, transfection of PRO cells, which spontaneously express or alpha 1,2-fucosyltransferase activity, with the FTA cDNA in the antisense orientation decreases expressi on of the H antigen together with their resistance to LAK cell lysis, but a gain, not to NK cell lysis. Furthermore, REG cells that are rejected by imm unocompetent syngeneic rats are similarly rejected by rats depleted of NK c ells by antibody 3.2.3, directed against the NKR-P1 molecule. Thus, the rej ection of REG cells by immunocompetent rats and their earlier reported incr eased tumorigenicity after transfection with an oil,2-fucosyltransferase cD NA cannot be ascribed to NK cell sensitivity or resistance, respectively. T he increased resistance to LAK cell lysis, however, may be relevant to tumo r progression. (C) 2000 Wiley-Liss, Inc.