Evaluation of the cytotoxic and apoptogenic effects of cinnamaldehyde on U87MG cells alone and in combination with doxorubicin

Figures

• 

  Fig. 1. U87MG cells morphological changes treated with DOX (5 μg/mL) and different concentrations of CA. (A) Control, (B) DOX (5 μg/mL), (C) CA (8 μg/mL), (D) DOX + CA (8 μg/mL), (E) CA (16 μg/mL), (F) DOX + CA (16 μg/mL), (G) CA (32 μg/mL), and (H) DOX + CA (32 μg/mL). CA, cinnamaldehyde; DOX, doxorubicin.

• 

  Fig. 2. Sub G1 cell cycle arrest induced by DOX and CA on U87MG cell line. (A) Control, (B) DOX (5 μg/mL), (C) CA (8 μg/mL), and (D) CA (8 μg/mL) + DOX (5 μg/mL). U87MG cells (104 cells) were treated for 24 h. Cells were harvested and labeled with propidium iodide (PI), and then analyzed by flow cytometer. CA, cinnamaldehyde; DOX, doxorubicin;

• 

  Fig. 3. Effect of different concentrations of CA (8, 16, and 32 μg/mL) on DOX (5 μg/mL)-induced mitochondrial membrane potential (MMP) collapse. U87MG cells were exposed to test compounds 24 h before analysis. Results are expressed as mean ± SEM of three separate experiments. *P < 0.05, **P < 0.01, and ***P < 0.001 indicate significant differences in comparison with control. CA, Cinnamaldehyde; DOX, doxorubicin.

• 

  Fig. 4. Effect of different concentrations of CA (8, 16, and 32 μg/mL) and DOX (5 μg/mL) on caspase-3 and -9 activities. Firstly cells pretreated with CA for 24 h before exposure to DOX (5 μg/mL). Caspase-3 and -9 activities measured by colorimetric detection of p-nitroaniline and expressed as percent of control. Results are expressed as mean ± SEM, n = 3. *P < 0.05 and **P < 0.01 indicate significant differences in comparison with control; and ##P < 0.01 shows significant differences relative to DOX group. CA, Cinnamaldehyde; DOX, doxorubicin.

• 

  Fig. 5. Effects of CA at 8 μg/mL alone and in combination with DOX (5 μg/mL) on expressions of Bax and Bcl-2 genes in U87MG cells. RNA was isolated, reverse transcribed to cDNA, and then amplified by a real-time PCR detection system to measure mRNA levels of Bax and Bcl-2. Target genes were normalized to β.actin. The data are presented as the mean ± SEM from three independent experiments. #P < 0.05 and ###P < 0.001 vs corresponding DOX group. CA, Cinnamaldehyde; DOX, doxorubicin.