Question

  What is programmed cell death of apoptosis? What should cancer cells do with respect to apoptosis that would help them grow? What is the normal function of BCL2 protooncogene? What would be the consequence of its overexpression in cancer?

Answer 1

If cells are no longer needed, they commit suicide by activating an intracellular death program. This process is therefore called programmed cell death, although it is more commonly called apoptosis. During apoptosis, the cell shrinks and pulls away from its neighbors. Then the surface of the cell appears to boil, with fragments breaking away and escaping like bubbles from a pot of hot water.

Cancer can be viewed as the result of a succession of genetic changes during which a normal cell is transformed into a malignant one while evasion of cell death is one of the essential changes in a cell that cause this malignant transformation. Cancer cells escape apoptosis by increasing or decreasing expression of anti- or pro-apoptotic genes, respectively. ... Moreover, cancer cells may also prevent apoptosis by changing the functions of anti- or pro-apoptotic proteins through post-translational modifications, such as phosphorylation.

BCL-2 is localized to the outer membrane of mitochondria, where it plays an important role in promoting cellular survival and inhibiting the actions of pro-apoptotic proteins. BCL-2 is known to regulate mitochondrial dynamics, and is involved in the regulation of mitochondrial fusion and fission.