Sunday, October 20, 2013
Turning on key enzyme blocks tumor formation
Katie Liu
October 20, 2013
Published: August 27, 2012
Link: http://web.mit.edu/newsoffice/2012/turning-on-key-enzyme-blocks-tumor-formation-0827.html
Summary:
Cancer cells put most of their energy into reproduction and growth, unlike regular cells. They rely on the help of certain enzymes to construct molecules that build up cell structures. When chemical compounds interrupt the function of this enzyme, it can prevent tumors from forming in mice, according to a study done at MIT. Cancer cells use a specific type of enzyme called pyruvate kinase that allows the cell to focus on growing and dividing quicker than normal. In normal cells, this enzyme allows a large ATP to be produced from the product of glycolysis. However, in cancer cells, the alternate form of this enzyme is less active, so instead of having more ATP produced, the products of glycolysis are being made into macromolecules essential for building and growing cells. This study suggest that cancerous growth can be stopped by raising the level of pyruvate kinase activity so the cell will have normal reactions. Drugs that change the properties of the altered enzyme into its original state hold possibilities for treating cancer. Tests have been run where chemical compounds that reverse the properties of the altered pyruvate kinase have been added into mice, and none of them developed tumors when they were exposed to human tumors.
Connection:
This article relates to our curriculum for this term since we've talked about enzymes in our second unit and cells for our third unit. We discussed the role of enzymes in chemical reactions, and how they work. This article talks about the role of a particular enzyme in cancerous cells, and how it’s causing cancer by causing less chemical reactions than normal cells which results in the cell producing building blocks like carbohydrates instead. We've also discussed cells and cellular reproduction by mitosis. Cancer cells are able to be harmful through massive cellular division and damage tissues that way. They grow uncontrollably and cancer is consider a disease of the cell cycle.
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Can raising the amount of pyruvate kinase kill cancer cells after they have formed a malignant tumor, or can they only prevent a malignant tumor from forming?
ReplyDeletePyrutate kinase in cancer cells are in an alternate form than the ones in normal cells. The pyruvate kinase in normal cells have high levels of activity and are always active contrary to the form of pyruvate kinase in cancer cells, which have low activity and are on and off. Having more pyrurvate kinase is not helpful as having more low activity enzymes are going to produce more building blocks for the cell to use to divide more. Larger amounts of pyruvate kinase won't kill cancer cells even if they do produce more ATP than structural molecules. With less building blocks, the cell stops dividing as often and is no longer a cancerous cell. By increasing the activity level of pyruvate kinase in cancer cells, it stops the growth of malignant tumors as cells no longer divide uncontrollably.
DeleteWill raising the level of pyruvate kinase activity effect the normal in a harmful way like it kills cancer cells and will it have have as harmful an effect on the body as radiotherapy or chemotherapy?
ReplyDeleteRaising the level of activity of pyruvate kinase will not have a harmful effect on the cells. In cancer cells, pyruvate kinase's low activity level directs energy into building up structural molecules instead of creating ATP which drives it into dividing uncontrollably. Raising the activity level of pyruvate kinase brings the level of metabolic activity back to normal and the cell is no longer cancerous. The cancer cells are not killed through this process and there are no harmful effects on the body.
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