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HeLa cells, cell biology, cancer?
A normal human cell has approximately 7.4 pg of DNA. A HeLa cell has 15 pg of DNA. What does the difference in DNA content suggest about the genome of HeLa cells? What abnormal process that occurs in many cancers cells could explain the difference?
So I know that HeLa cells have double the amount of DNA, so does that mean they have a larger genome? And I know cancer cells proflierate rapidly, but do they do that only because they have more DNA? Can someone clarify this all for me?
- Bob D1Lv 710 years agoFavorite Answer
It is one of those chicken and egg scenarios, which came first? It is not clear to me if anyone knows for sure if alterations in genomic content results in out of control cell division, or is it out of control cell division results in altered genomic content? Here's what I believe: It is the sequence and accumulation of point mutations in the cell division "check point" regulator genes (Oncogenes and Suppressor genes) that lead to rapid out of control cell proliferation common to most malignancies. While it is true that the nucleus of cancer cells are larger than that found in ordinary somatic cells, this is likely due to suppressed embryonic genes becoming reactivated during the cell's transformation from normal to cancerous. As you may already know, there is considerable chromosomal breakage and there can be an associated phenomenon called gene amplification (where one gene type may be duplicated many times). It turns out that for many genes on intact chromosomes and on broken chromosomes, transcription and translation from gene product to protein can continue almost normally. Many errors are simply the result of inappropriate gene expression at the wrong time, etc.
What I believe eventually happens especially with aggressive cancers is that because of a break down in gene regulation, the cell tries to undergo both mitotic cell division and meiotic cell division at the same time. This may account for de-differentiation of the cell and for chromosomal breakage. What you are looking for to account for the increased DNA nucleic acid is: Gene duplication (amplification) and the reactivation of gene sequences that were normally turned off during the cells normal precancerous state.
Here's some links:
Cancer biology flashcard sets
Cell Biology and Cancer
This book will answer any of your questions on the nature of cancer. It's well worth the small cost.
GENES AND THE BIOLOGY OF CANCER
by Harold Varmus and Robert A. Weinberg
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