چكيده لاتين :
Background: Microtubules (MT) are in1portant components of cell cytoskeleton and play key roles in cell
motility n1itosis and meiosis. They are also the targets of several anticancer agents which indicating their
importance in maintaining cell viability. Microtubular reorganization contributing to apoptotic morphology
occurs in normal and neoplastic cells undergoing apoptosis induced by cytotoxic drugs. The aim of this study
was to correlate the changes in the MT with behavior of the y-tubulin in apoptotic cell, and to see if apoptitic
MT showed biochemical characteristics of stable MT. Methods: Apoptosis was induced in the human
leukemia cells (HL-60) by treatment with 1 JiM of all-trans retinoic acid over a 5-day period. The time course
of changes was assessed using flow cytometry, DNA fragmentation and immunocytochen1istry in cells labeled
for a-tubulins, acetylated a-tubulin and y-tubulin. Results: The results indicated that y-tubulin content is
increased after cells have gone through the apoptosis with a diffuse cytoplasmic pattern. a-tubulin did not
reveal any specific pattern of polymerization in apoptotic cells and acetylated a-tubulin content was also
decreased in comparison with non-apoptotic cells. Conclusion: Our results support the idea that microtubule
reorganization is an important factor of the mammalian cells response to apoptosis, and the altered properties
of the MT did not reflect changes in function as apoptosis progresses. Iran. Biomed. J. 11 (4): 209-214,2007
