Lectin-resistant B16 melanoma cells exhibit an altered response to MSH and cholera toxin

Abstract

Mouse B16 melanoma cells respond to melanocyte-stimulating hormone (MSH) or cholera toxin (CT) with an accumulation of cAMP. The kinetics and dose-response of MSH were examined in the B16 parent line and two cell clones derived from it that exhibited wheat germ agglutinin (WGA) resistance [1]. These WGA lectin-resistant cells, designated W 4 and W 5 showed a greater response to MSH and CT than the parent B16 cells. Exposure of the W 4 and W 5 cells to lotus lectin or ricin respectively, led to the previously described [2] selection of cell clones that were resistant to lotus lectin (W 4L) and ricin (W 5R). The W 4L and W 5R cells which were shown [2] to be as sensitive as the B16 parent to WGA (i.e., were phenotypically reverted to WGA sensitivity), were also found to respond to MSH in a manner similar to the B16 parent. Since lectin sensitivity has been directly correlated in these cell clones with the membrane's oligosaccharides and glycopeptide pattern, these data suggest that the cellular binding and/or biological response to hormones is influenced by the carbohydrate composition of the plasma membrane.