Two multidrug resistant human acute lymphocytic leukemia cell lines (L_l00 and L₁₀₀₀) were developed by exposing parental cells (L₀) to progressively increased concentrations of vincristine sulfate (VCR). These cells have a novel multilobulated nucleus and a distinct microtubule (MT) organization that may be due to the perturbation of the cytoskeleton induced by VCR. The expression of MT and microtubule-associated proteins (MAPS) of the L₁₀₀ and the L₁₀₀ cells were compared to that of the Locells. A 28 KD protein of p1 6.9 and a 31 KD protein of pI14.4 were found to be overexpressed in L₁₀₀₀ and L_s1000 cells. Moreover, a 38 KD protein was found to be expressed in L₀ cells but not can be detected in L₁₀₀ and L₁₀₀₀ cells. The distinct MT organization and nuclear morphology of these cells m...[ Read more ]

Two multidrug resistant human acute lymphocytic leukemia cell lines (L_l00 and L₁₀₀₀) were developed by exposing parental cells (L₀) to progressively increased concentrations of vincristine sulfate (VCR). These cells have a novel multilobulated nucleus and a distinct microtubule (MT) organization that may be due to the perturbation of the cytoskeleton induced by VCR. The expression of MT and microtubule-associated proteins (MAPS) of the L₁₀₀ and the L₁₀₀ cells were compared to that of the Locells. A 28 KD protein of p1 6.9 and a 31 KD protein of pI14.4 were found to be overexpressed in L₁₀₀₀ and L_s1000 cells. Moreover, a 38 KD protein was found to be expressed in L₀ cells but not can be detected in L₁₀₀ and L₁₀₀₀ cells. The distinct MT organization and nuclear morphology of these cells may be due to the differential expression of the MAPS. The differential expression of these MAPS is correlated to the multidrug resistance (MDR) phenotype of these cells. These data suggest that these MAPS may be associated with the mechanism of MDR.