Dissimilar invasive and metastatic behavior of vincristine and doxorubicin-resistant cell lines derived from a murine T cell lymphoid leukemia.

Multidrug resistance (MDR) lines from a murine T-cell lymphoid leukemia were selected in increasing vincristine (VCR) or doxorubicin (DOX) concentrations. Surface markers were determined by flow cytometry in both resistant (LBR-V 160 and LBR-D 160) and sensitive (LBR-) cell lines. Results obtained revealed similar expression of CD25, CD24, CD8, CD4, C18 and CD44, while differences in binding to hyaluronic acid (HA) were found. LBR- and LBR-D 160 bound to HA only after phorbol ester (PMA) activation, while LBR-V160 failed to bind HA even after PMA treatment. Histopathological analysis disclosed that LBR-V160 was less invasive than LBR- and LBR-D160 cell lines. In vitro growth of cell lines analyzed by sulforhodamine-B uptake showed that doubling time for the three lines was 10.24 h (LBR-), 16.75 h (LBR-V160) and 16.29 h (LBR-D160). Mortality rate was determined after i.p. injection of 10(4) cells. Mice inoculated with LBR- died at 23 2.11) days, while those inoculated with LBR-V160 or LBR-D160 died at 41 (+/- 9.53) or 41 (+/- 4.96) days, respectively. Our results demonstrated that leukemic murine T cells cultured in the long-term presence of VCR or DOX not only presented changes in the resistance phenotype but also variations in their growth and metastatic pattern.