Abnormal Number of Chromosomes is One Step in Cancer Development

Researchers have produced the first laboratory evidence to show that a cell’s possession of an abnormal numbers of chromosomes contributes to the development of cancers. Their report on the role of this chromosomal instability, known as aneuploidy, appears in today’s online edition of the Feb. 3 Journal of Cell Biology. Because 85 percent of human cancer cells possess an abnormal number of chromosomes, researchers have long been curious about the role of aneuploidy in the multistep cancer process.

Cancer squeezes through the gaps

Cancer cells move around the body (become metastatic) by chopping up the dense matrix that surrounds them. But drugs that prevent the chopping have been disappointing in animal and human anti-cancer trials. Now researchers provide an explanation for this failure: the drug-treated cells revert to a primordial, ameboid form of cell movement that allows them to squeeze through gaps in the matrix.

Cell keeps spare set of DNA to ensure offspring gets fresh start

This is a little complex, but bear with us. Nearly all cells house their DNA inside a nucleus. But a little one-celled critter called Tetrahymena houses different versions of its DNA in each of its two nuclei. Researchers have found that the smaller nucleus (called the micronucleus) just keeps the cell’s full genome safe, acting as a sort of “lock box.” The larger nucleus (called the macronucleus) uses the DNA to regulate the cell’s life functions. When the cell mates to create a new generation, the two work together to compare the cell’s current DNA against what’s been stored in the lock box. If any foreign genes have snuck in (like from a virus) they nuclei eliminate it, to make sure baby gets a fresh start. Pretty neat, with possible implications for larger organisms, too.

Fat cells converted to bone

Pre-cells destined to become fat can be converted instead into true bone cells in
response to outside signals, say researchers at the University of California, San Francisco. The finding could pave the way for scientists to replenish lost bone cells in patients with conditions like osteoporosis, and to help repair bone defects. The new bone cells have all the hallmarks associated with mature bone formation, including production of bone proteins and calcification, the UCSF team says.

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