The Effects of Thymoquinone and Doxorubicin on Leukemia and Cardiomyocyte Cell Lines

We describe to the findings of cellular activity in RAW 264.7 leukemia cells and CRL 1764 Rat2 cardiomyocyte when subjected to thymoquinone, doxorubicin and in combination therapy. Our study included the determination of dosing for thymoquinone that will provide 50% cell apoptosis in RAW 264.7 murine leukemia cells. RAW leukemia cells and cardiac myocytes were treated with thymoquinone and doxorubicin, both alone and in combination for 24, 48 and 72 hours. Cells were examined for protein assay by Pierce BCA method, glutathione, and nitric oxide determination. Cell morphology and apoptotic activity were performed in standard methods. Data analysis was performed utilizing the Jandel Computer Statistical Analysis Software (SigmaStat). Descriptive statistics were performed where the findings will demonstrate the findings as means +/- standard deviation (SD) or means +/- standard error of the mean (SE). Along with descriptive statistics, analysis of variance (ANOVA) was also performed. Thymoquinone was administered at low (10muM), medium (50muM), and high (100muM). Cell morphology in RAW 264.7 murine leukemia cells, was aggressive in all dosing levels with thymoquinone. Lower dosing of thymoquinone at 1muM was administered to RAW 264.7 murine leukemia cells and morphology evaluated at 24, 48 and 72 hours. Our findings suggested a dose of thymoquinone at 1muM was effective in providing a 50% cell destruction of RAW 264.7 leukemia cells. These results suggested that low doses of thymoquinone provided increased apoptotic activity with treatment to RAW 264.7 murine rat leukemia cells. Synergistic effects were observed in the morphology with increased apoptosis of RAW 264.7 leukemia cells. Thymoquinone dosing for RAW 264.7 leukemia cells was determined by our research to provide 50% reduction in cell viability at 1muM, which is lower than previous published studies. Thymoquinone dose of 1muM provided some protective activity for RAW 264.7 leukemia cells following initial doxorubicin dosing in 24 hours. The duration of treatment with doxorubicin + thymoquinone provided the effect of apoptosis and a reduction in glutathione levels. Findings suggest RAW 264.7 leukemia cells apoptosis increased in combination therapy and is time dependent with thymoquinone at 1muM + doxorubicin at standard dosing in acute lymphoblastic leukemia. Peak effects of doxorubicin was apparent at 48 hours with reduction in glutathione levels in RAW 264.7 murine leukemia cells. Thymoquinone at 1muM preserved the cell morphology of CRL 1764 Rat2 cardiomyocytes when compared to control. Glutathione levels in cardiomyocytes were elevated at 72 hours, following the initial insult of doxorubicin peak action. Combination treatment with doxorubicin and thymoquinone demonstrated significant CRL 1764 Rat2 cardiomyocyte survival when compared to controls. Data suggest that thymoquinone when administered at 1muM, in combination with standard dosing of doxorubicin is effective in cell destruction of RAW 264.7 murine leukemia cells, while providing protective activity of CRL 1764 Rat2 cardiomyocytes.