The Inhibition of Cancerous Stem Cells

PDGF receptor p (PDGFRB), and c-kit, a cytokine receptor expressed on the surface of hematopoietic stem cells as well as other cell types. As compared with the two drugs on the market, sorafenib (Nexavar) by Bayer Pharmaceuticals Corp. and Onyx Pharmaceuticals, Inc. and sunitinib (Sutent) by Pfizer, Inc., cediranib inhibits VEGFR targets with improved potency. It is currently in Phase II/III development for advanced non-small cell lung cancer and advanced colorectal cancer. 

Of special note in Chi s article is the discussion of the RTK inhibition of cancer. RTK refers to receptor tyrosine kinases, as the enzyme tyrosine kinase is implicated in the formation of refractory cancerous stem cells, described in Chapter 10, and the search has been enjoined for inhibitors. The article notes that when tumors reach a certain size (approximately 2 mm in diameter), growth factors or proteins are released in overwhelming amounts into nearby tissues, thus initiating angiogenesis. The growth factors subsequently bind to their RTKs within endothelial cells in the blood cells. This results in activation of otherwise dormant endothelial cells ( endothelial pertains to the internal cavities of the body). This results in the division and migration of the endothelial cells toward the diseased tumorous or cancerous cells. But for this to happen, a network of new blood vessels must be formed. 

It will be noted time and again that there is a difference between the metabolism of cancer cells and normal cells, and the determination of selective and nontoxic enzyme inhibitors for cancer cell metabolic pathways may provide the elusive magic bullet. Lastly, it can be said that the exciting developments about selectively inhibiting or blocking cancerous stem cells, as described above, give an extra hope to cancer victims. 

FOX03 gene product proteins produced increased tumor spheres. The dual inhibitor of PI3K and mTOR, NVP-BEZ235 vide supra) inhibited tumor sphere formation and growth of prostate cancer stem cells [2053]. 

It is important to note that diet is a complex mixture that contain compounds with varying activity. Chemical stimulators of colon cancer growth include bile acids, 1,2-diglycerides and prostaglandins which stem from consumption of fat. In contrast, fruits and vegetables contain substances such as carotenoids, flavonoids and fibre, which may inhibit cancer cell growth, and the risk of colon cancer appears to be mirrored by the ratio of plant sterols to cholesterol in the... 

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