CONICET | Buscador de Institutos y Recursos Humanos

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-V160 and LBR-D160) and sensitive (LBR-) cell lines. Results obtained revealed similar expression of CD25, CD24, CD8, CD4, CD18 and CD44, while differences in binding to hyaluronic acid (HA) were found. LBR- and LBR-D160 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 104 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.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 104 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.

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