Methylsulfonylmethane sensitizes endometrial cancer cells to doxorubicin

Figures

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  Graphical abstract

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  Fig. 1. a MSM decreases viability of EC cells in a dose-dependent manner. The viability of cells was evaluated after exposure to MSM for 24 h with AlamarBlue® reagent. The results are expressed as a % of control cells (100% viability for non-treated cells). p < 0.05 was considered statistically significant. **p < 0.01, ***p < 0.001. MSM methylsulfonylmethane. b Pre-treatment with MSM before DOX treatment decreases the viability of EC cells as compared to DOX treatment alone. Cells were pre-treated with MSM or experimental medium for 24 h before DOX treatment for 24 h. The viability was determined with AlamarBlue® reagent and expressed as % of Cnt cells (100% viability for non-treated cells). p < 0.05 was considered statistically significant. *p < 0.05, **p < 0.01, ***p < 0.001 as compared to Cnt. MSM methylsulfonylmethane, DOX doxorubicin, Cnt control

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  Fig. 2. a MSM increases DOX-induced apoptosis in EC cells. The results are expressed as % of gated cells. p < 0.05 was considered statistically significant. *p < 0.05, ***p < 0.001 as compared to Cnt. ##p < 0.01, ###p < 0.001 as compared to MSM treatment in the same dose. MSM methylsulfonylmethane, DOX doxorubicin, Cnt control. b Pre-treatment with MSM before DOX treatment increases mitochondrial potential in EC cells. The results are expressed as % of gated cells. p < 0.05 was considered statistically significant. *p < 0.05, ***p < 0.001 as compared to Cnt. ##p < 0.01, ###p < 0.001 as compared to MSM treatment in the same dose. MSM methylsulfonylmethane, DOX doxorubicin, Cnt control. c MSM increases DOX-induced DNA damage in EC cells. DNA damage was evaluated with Muse® Multicolor DNA damage. The results are expressed as % of cells gated. p < 0.05 was considered statistically significant. ***p < 0.001 as compared to Cnt. ###p < 0.001 as compared to MSM treatment. In DAPI staining with white arrows are marked fragmentated nuclei of cells. MSM methylsulfonylmethane, DOX doxorubicin, Cnt control

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  Fig. 3. a The expression of PARP1 after MSM pre-treatment before exposure to DOX. The expression was evaluated with RTqPCR. The results are expressed as a relative expression. p < 0.05 was considered statistically significant. *p < 0.05, **p < 0.01, ***p < 0.001 as compared to Cnt. #p < 0.05, ###p < 0.001 as compared to MSM-treated cells. b The representative results of Western blot evaluation of cleaved PARP1 form. MSM methylsulfonylmethane, DOX doxorubicin, Cnt control

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  Fig. 4. a The expression of SOD1 and HIF-1α after MSM and DOX treatment. The expression was evaluated with RTqPCR. The results are expressed as a relative expression. b The expression of SOD1 on protein level. The expression was evaluated with Western blot and presented as representative results. p < 0.05 was considered statistically significant. *p < 0.05, **p < 0.01, ***p < 0.001 as compared to Cnt. ##p < 0.01, ###p < 0.001 as compared to MSM-treated cells. MSM methylsulfonylmethane, DOX doxorubicin, Cnt control

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  Fig. 5. The expression of Akt and p44–42 after DOX and MSM exposure in EC cell lines. The expression was evaluated with Western blot and presented as representative results. MSM methylsulfonylmethane, DOX doxorubicin, Cnt control

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  Fig. 6. a Cell cycle distribution after pretreated with MSM EC cells before DOX exposure. The cell cycle distribution is expressed as % of gated cells. p < 0.05 was considered statistically significant. *p < 0.05, **p < 0.01, ***p < 0.001 as compared to Cnt. #p < 0.05, ##p < 0.01, ###p < 0.001 as compared to MSM treatment. MSM methylsulfonylmethane, DOX doxorubicin, Cnt control. b Expression of CDKN1A after DOX, MSM, and MSM + DOX treatment in EC cells. The expression of CDKN1A was evaluated in RTqPCR. The results are expressed as a relative expression. p < 0.05 was considered statistically significant. *p < 0.05, **p < 0.01, ***p < 0.001 as compared to Cnt. #p < 0.05, ###p < 0.001 as compared to MSM treatment. MSM methylsulfonylmethane, DOX doxorubicin, Cnt control