Determinants of differential liver-colonizing potential of variants of the MCA-38 murine colon cancer cell line

We investigated factors that might contribute to the differing liver tumor colonizing potentials of MCA-38 colonic cancer cell line variants injected into the ileocolic veins of C57B1/6J mice. Non-colonizing (MCA-38 CD) cells were sensitive to lysis by hepatic ntural killer (NK) cells in vitro (⁵¹ Cr-release assay) and cells with high liver-colonizing potential (MCA-38 LD) were resistant. Following abrogation of NK activity by treatment with anti-asialoG_M1, liver-colonizing ability of LD cells but not CD cells was enhanced. MCA-38 CD cells were, however, capable of initial liver colonization after ileocolic vein injection. Differing patterns of membrane sialylation may have contributed to the contrasting hepatic tumorigenicities of LD and CD cells; β-galactoside α2,6-sialyltransferase mRNA levels and activity were ∼ four-fold higher in LD than CD cells and qualitative and quantitative differences existed between their ganglioside profiles. In the MCA-38 model outlined, tumor cell susceptibility or resistance to NK lysis was a relatively unimportant determinant of liver-colonizing potential.