Pitt Logo LinkContact Us

THE CONSEQUENCES OF MITOTIC SEGREGATION DEFECTS IN ORAL CANCER CELLS AND THEIR CONTRIBUTION TO CHROMOSOMAL INSTABILITY

Hoffelder, Diane R. (2002) THE CONSEQUENCES OF MITOTIC SEGREGATION DEFECTS IN ORAL CANCER CELLS AND THEIR CONTRIBUTION TO CHROMOSOMAL INSTABILITY. Master's Thesis, University of Pittsburgh.

[img]
Preview
PDF (The Consequences of Mitotic Segregation Defects in Oral Cancer Cells and Their Contribution to Chromosomal Instability) - Primary Text
Download (1887Kb) | Preview
    [img] Video (QuickTime) (Movie 1: Normal division) - Supplemental Material
    Download (2463Kb)
      [img] Video (QuickTime) (Movie 2: Anaphase bridge 1) - Supplemental Material
      Download (20Mb)
        [img] Video (QuickTime) (Movie 3: Anaphase bridge 2) - Supplemental Material
        Download (13Mb)
          [img] Video (QuickTime) (Movie 4: Multipolar spindle) - Supplemental Material
          Download (8Mb)
            [img] Video (QuickTime) (Movie 5: Daughter cells with defective division) - Supplemental Material
            Download (2723Kb)
              [img] Video (QuickTime) (Movie 6: Anaphase bridge leading to formation of a micronucleus) - Supplemental Material
              Download (9Mb)
                [img] Video (QuickTime) (Movie 7: Anaphase bridge and micronucleus) - Supplemental Material
                Download (2763Kb)
                  [img] Video (QuickTime) (Movie 8: Micronucleus movement) - Supplemental Material
                  Download (6Mb)
                    [img] Video (QuickTime) (Movie 9: Montage of micronucleus movement) - Supplemental Material
                    Download (14Mb)

                      Abstract

                      Mitotic segregation defects such as multipolar spindles, anaphase bridges, and micronuclei have long been observed in cancer cells, but it is not known whether these defects lead to aneuploidy or even contribute to tumorigenesis. We visualize living oral squamous carcinoma cells with stable expression of GFP-histone H2B fusion. Expression of this fusion protein labels chromosomes clearly and does not disrupt the cell cycle, alter the doubling time or produce any defects previously unseen in fixed cells. These carcinoma cells survive the formation of anaphase bridges and micronuclei and complete a second cell division in the same amount of time as unaffected cells. Micronuclei were formed after every division that contained an anaphase bridge in cells we examined. Most often, each daughter cell contained a micronucleus. These results suggest that the chromosome breaks at multiple points along its length and breaking may not be due to a "tug of war" between spindle poles. The movement of micronuclei was very dynamic compared to the nuclei during interphase and micronuclei do not appear to be transcriptionally active. Using long-term live cell imaging we were also able to observe the fate of these cells through two divisions and have determined the length of each phase of mitosis. Anaphase bridges and lagging metaphase chromosomes both lengthen mitosis, suggesting that the mitotic spindle checkpoints are at least partially active in cells. The mitotic delays occurred during metaphase in these defective cells. We have also analyzed centrosomal components including the mitotic apparatus protein, NUMA. No correlations were found between protein expression of NuMA and gene amplification or segregation defects. In summary, we have shown that cells continue to proliferate after the occurrence of mitotic defects and these defects contribute to chromosomal instability.


                      Share

                      Citation/Export:
                      Social Networking:

                      Details

                      Item Type: University of Pittsburgh ETD
                      Creators/Authors:
                      CreatorsEmailORCID
                      Hoffelder, Diane R.drhst23@pitt.edu
                      ETD Committee:
                      ETD Committee TypeCommittee MemberEmailORCID
                      Committee ChairSaunders, William S
                      Committee MemberChapman, Deborah L
                      Committee MemberBrodsky, Jeffrey
                      Committee MemberHildebrand, Jeffrey
                      Title: THE CONSEQUENCES OF MITOTIC SEGREGATION DEFECTS IN ORAL CANCER CELLS AND THEIR CONTRIBUTION TO CHROMOSOMAL INSTABILITY
                      Status: Unpublished
                      Abstract: Mitotic segregation defects such as multipolar spindles, anaphase bridges, and micronuclei have long been observed in cancer cells, but it is not known whether these defects lead to aneuploidy or even contribute to tumorigenesis. We visualize living oral squamous carcinoma cells with stable expression of GFP-histone H2B fusion. Expression of this fusion protein labels chromosomes clearly and does not disrupt the cell cycle, alter the doubling time or produce any defects previously unseen in fixed cells. These carcinoma cells survive the formation of anaphase bridges and micronuclei and complete a second cell division in the same amount of time as unaffected cells. Micronuclei were formed after every division that contained an anaphase bridge in cells we examined. Most often, each daughter cell contained a micronucleus. These results suggest that the chromosome breaks at multiple points along its length and breaking may not be due to a "tug of war" between spindle poles. The movement of micronuclei was very dynamic compared to the nuclei during interphase and micronuclei do not appear to be transcriptionally active. Using long-term live cell imaging we were also able to observe the fate of these cells through two divisions and have determined the length of each phase of mitosis. Anaphase bridges and lagging metaphase chromosomes both lengthen mitosis, suggesting that the mitotic spindle checkpoints are at least partially active in cells. The mitotic delays occurred during metaphase in these defective cells. We have also analyzed centrosomal components including the mitotic apparatus protein, NUMA. No correlations were found between protein expression of NuMA and gene amplification or segregation defects. In summary, we have shown that cells continue to proliferate after the occurrence of mitotic defects and these defects contribute to chromosomal instability.
                      Date: 16 July 2002
                      Date Type: Completion
                      Defense Date: 30 April 2002
                      Approval Date: 16 July 2002
                      Submission Date: 07 May 2002
                      Release Date: 16 July 2002
                      Access Restriction: No restriction; The work is available for access worldwide immediately.
                      Patent pending: No
                      Institution: University of Pittsburgh
                      Thesis Type: Master's Thesis
                      Refereed: Yes
                      Degree: MS - Master of Science
                      URN: etd-05072002-121540
                      Uncontrolled Keywords: anaphase bridge; GFP histone; mitosis; oral cancer; segregational defects
                      Schools and Programs: Dietrich School of Arts and Sciences > Biological Sciences
                      Date Deposited: 10 Nov 2011 14:43
                      Last Modified: 02 Feb 2013 01:16
                      Other ID: http://etd.library.pitt.edu:80/ETD/available/etd-05072002-121540/, etd-05072002-121540

                      Actions (login required)

                      View Item

                      Document Downloads