Control of cell proliferation

2020-10-06 13:19:50

Whether the cell can enter the cycle is regulated by environmental signals. The low cell density makes the periphery of the cell unconstrained, and when the cell can spread freely, it promotes mitotic growth factors such as epidermal growth factor (EGF), fibroblast growth factor (FGF), or Platelet-derived growth factor (PDGF) can interact with cell surface receptors, thereby stimulating cells to enter the cell cycle. High cell density can inhibit normal cell proliferation, but it can not inhibit the proliferation of transformed cells. Cells contacting each other can cause proliferation inhibition. The change in cell shape caused by crowding and stretch limitation further strengthens the inhibitory effect. The positive and negative activating factors in the cell regulate cell proliferation.

When the receptor phosphorylated in the intracellular domain is combined with growth factors, the signal transduction system is activated, and the positively activated factors such as cyclin are up-regulated to promote the cell cycle [Planas-Silva and Weinberg, 1997, Reed 2003]; Negative activating factors, such as p53 [Sager 1992, Mcllwrath et al., 1994]. P16 [Russo et al., 1998] or the product of the Rb gene [Sager 1992], prevent cell cycle progression at cell cycle restriction points or checkpoints. Through cell membrane receptors and signaling pathways, extracellular regulatory components, including positive activation factors such as PDGF, negative activation factors such as TGF-Î², are associated with intracellular effector components.This process often involves protein phosphorylation and second messengers. For example, the participation of Camp, Ca2 + and diacylglycerol [Alberts et al., 2002] studies on oncogenes and tumor suppressor genes of tumor cells show that there are indeed evidences for many of the above steps to regulate cell proliferation, which is helpful for clinical Looking for ways to effectively regulate the proliferation of tumor cells, and the direct benefits brought by it can better explain why growth factors can regulate the proliferation of cultured cells [Jenkins, 1992],

These studies also help identify genes that enhance cell proliferation, some of which can be used to establish immortal cell lines.

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