Immunobiological characterization of cell-lines resistant to Doxorubicin and Vincristine

LOPES EC; ERNST G; AULICINO P; FABRIS V; GARCÍA MG; ALVAREZ E; MERANI S; HAJOS S

Estocolmo, Suecia

Congreso; 11th International Congress of Immunology; 2001

Cell lines resistant to either vincristine (LBR-V) or doxorubicin (LBR-D) were obtained after culture of tumor cells from a murine spontaneous leukemia. Cytogenetic analysis showed dissimilar alterations in chromosome (chr) 5, where mdr genes are located. LBR-V showed trisomies of chr 4, 5, 14, 15 and 19 while LBR-D showed monosomy of chr 11 and trisomies of chr 6, 13, 14 and 18 and t(5;12). Surface markers determined by flow cytometry in both resistant and sensitive (LBR-) lines revealed similar expression of CD25+, CD24+, CD18+, CD8+ and CD4-. However, differences in CD44 expression and in constitutive binding to hyaluronic acid (HA) were found. LBR- (CD44hi) and LBR-D (CD44lo) bound HA only after phorbol ester (PMA) activation, while LBR-V (CD44hi) did not bind HA even after PMA treatment. In vitro growth of cell lines analyzed by uptake of Sulphorodamine-B showed that duplication time for different lines was 4,63h (LBR-), 5,52h (LBR-V) and 5,01h (LBR-D). Mortality rate was determined after ip injection of 10000 of either cells. Mice inoculated with LBR- died at 23days while mice inoculated with LBR-V or LBR-D died at 41 days. Conclusion: both resistant lines showed chr alterations, similar expression of surface markers while tumor growth was delayed suggesting lost of aggressiveness as a result of drug treatment.