The hypothesis that cell volume and the progression of the cell cycle are interdependent has surfaced off and on in the cell cycle literature for the past 30 years. However, a conclusion as to how cell volume is mechanistically involved in cell division has not been reached in mammalian cells. The aim of this dissertation was to establish how volume changes modulate cell cycle progression. Most of the studies addressing this question have examined mass content yet, more recently, focus has been placed on intracellular water, which is determined by the balance between mechanical and osmotic forces. As a result, ion channels and transporters which regulate intracellular osmotic content are integral to the maintenance of cell volume. In this dissertation, I show that a large, rapid and regulated volume decrease occurs as glioma cells progress through mitosis. I refer to this process as pre-mitotic condensation (PMC). This process is functionally linked to DNA condensation prior to cell division as the two events occur simultaneously, and inhibition of PMC results in a prolongation of DNA condensation. Further, my data demonstrates that glioma cells actively accumulate chloride, which acts as the primary energetic driving for cell volume changes in these cells. During the process of PMC, this gradient drives the efflux of chloride through ClC3 channels, which mediates water loss and the volume decrease. Interestingly, chloride accumulation to similar levels can be observed in immature astrocytes and neurons, suggesting that glioma cells recapitulate the biology of immature proliferating cells in the brain. This also suggests that my findings may have broader applicability to cell division in both neural cells and cancer.

xii, 132 p. : ill., digital, PDF file.

Neurobiology

Joint Health Sciences

Voltage Gated Chloride Channels Pre-miotic Condensation DND Condensation C1C3 Mitosis Volume Regulation

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