So, I test plant extracts for their cytotoxicity effect using XTT cell proliferation assay kit. As positive controls vincristine and docetaxel are used. The problem is I can't observe dose dependent response for positive controls. I tried various initial concentrations and 2-fold, 5-fold and 10-fold serial dilutions (6 series). The last initial concentrations I tried are 13 mcrg/mL for vincristine and 33 mcrM for docetaxel. After 48 hours in both controls I observed around 80% inhibition in all doses with 10-fold serial dilutions. Basically the last dose is max.dose/106. Can't think of a reasonable explanation. Any ideas are welcome. Thanks in advance.
Update: Target cells are T24 and UMUC3 human bladder carcinoma cells
Yea these days people such as the first guy that answered just post some key word matching paper from google that doesn't help at all!
I can try to help you with this but Im not completely sure that i understand what are you saying ( I mean what doses did you use)
First try finding some paper that shows the LD50 doses of vincristine and docetaxel in any cell culture. After wards try repeating those doses and 2 times up and down doses, or serial dilutions and hope for good preliminary results :)
Afterward you can focus on those doses.
On the other hand if you already have some doses previously used in your lab try to repeat the recalculate doses and dilutions again. Maybe your making some technical error that your not seeing right now.
All best
Nikola
Thanks for your answer Nikola. I've mentioned the doses of vincristine and docetaxel used in the assay in my question. Max doses in the first well 13 mcrg/mL for vincristine and 33 mcrM for docetaxel. Then at different times I tried 2-fold, 5-fold and 10-fold dilutions and I can say I repeated the assay 15-20 times. And I researched the doses for the carcinoma cells, and the first doses I used are somewhat higher than the ones in the literature. But the other problem is that even at a very low dose (maxdose/106) I get around 80% survival rate, similar to the highest dose, which makes no sense. Like I said, I repeated the assay 15-20 times with various serial dilutions, recalculated the doses several times and still no solution.
- Badges
- Science topic
- Similar topics
- Biological Science
- Botany
- Pharmaceutical Botany
- Plant Extracts