- I am doing MTTassay against bone cancer cell line . My test compound is crude plant extract rich in polyphenols which are antioxidant in nature. I took the plant sample concentration in micrograms (25, 50, 75 and 100 ug/ml). I found treated cells are showing more absorbance than the control. Is it possible that the plant rich in polyphenols having anticancer activity can increase cell proliferation .
Well, on the downside of it, and from previous practical experience of working with flavonoid/ phenol/ polyphenol extracts, clearly this increas ein absorbance is due to interference from the compounds/ extract at the MTT screening absorbance wavelength or OD of 570 nm which is a visible range. And the concentrations you are using of 100s of microgram which is on higher side, can easily contribute to the increase in absorbance in the 200 micro-liter of cell soup. Researchers easily over look this and conclude things erroneously. For each concentration prepare a blank with the same amount of extracts int he cell soup with MTT and NO CELLS ADDED-which would be the perfect blank. This value will be deducted from each of your cells +treatments to get the right OD values for further interpretations. Polyphenol extracts inhibiting cancer cells line mechanisms is a OLD and well established concept and exemplary works are all there in literature- be the mode of action through binding proteins, interfering with basic oxidative metabolism, as antioxidants, as cell membrane damaging agents- they can act in multiple manner. Read along. Good luck and do not please over look flaws. Also perform "intra-day and inter day assays" both to get replicates of around 6-8 per concentration or even more, to come to any conclusions with proper statistical tests and so on. Hope it helps, Biswa
Hi Anupam... I had the same problem... Usually, this is because you don't remove all the medium of the wells before of resuspend the formazan with DMSO... Other possibility is a bad read of the absorbance... Do you add extract to the blanks?... I have worked with oils essentials in tumor cells (U937, K562, Jurkat) and the phenolic compounds induce programed cell death in a pathway mitochondrial dependent, I don't believe that the phenomenon of "cell proliferation" be real... I think that its a technical error... Good luck!!..
sorry, i forgot to mention that i diluted my plant extract in cell culture media.
It is becoming established that antioxidants can increase the proliferation of cancer cells.
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