Effect of carboplatin injection on Bcl-2 protein expression and apoptosis induction in Raji cells

To investigate the effects of carboplatin (CBP) injection on apoptosis induction in the human lymphoma cell line Raji and to explore the underlying mechanism, Raji cells were randomly divided into two treatment groups. Cells in the experimental groups were treated with 15 μM CBP injection, those in the control groups were treated with solvent, and both groups were treated for 24, 48 and 72 h. Cells from each group were collected for subsequent assays. For each group, the relative expression of B-cell lymphoma-2 (Bcl-2) was determined by Western blot (WB), the expression pattern of Bcl-2 was observed by immunocytochemistry (ICC), and cell apoptosis was observed after Hoechst 33342 staining. Real-time PCR detection of the relative expression levels of the Bax and caspase-3 genes in each group of cells were performed. The WB results showed that the relative expression of the Bcl-2 protein significantly decreased 48 and 72 h after treatment in the CBP groups compared with the control groups (P<0.001), and a significant decrease in the expression of this protein was also noted at 48 h vs 24 h, 72 h vs 48 h, and 72 h vs 24 h with extremely significant differences (P<0.001). Moreover, the expression of the Bcl-2 protein decreased as the duration of CBP treatment increased, showing a time-dependent manner. The ICC results were consistent with the WB findings. The expression of the Bcl-2 protein in the CBP treatment group was significantly reduced 48 h and 72 h after treatment compared with the control group (P<0.001). A time-dependent manner was also noted in the expression of this protein, i.e., the expression level decreased gradually at 24, 48, and 72 h after treatment with statistically significant differences (P<0.001). Hoechst 33342 staining showed that the apoptosis rates at the three time points in the treatment groups were significantly higher than those in the control groups (P<0.001), and a time-effect relationship was observed. The apoptosis rate increased over time with a significant difference (P<0.05). The PCR results showed that the Bax and caspase-3 gene expression trend was the same but opposite that of Bcl-2. After treatment for 24 h and 48 h, the gene expression of the medication groups decreased with a very significant difference (P<0.001), and with prolonged action time, the relative expression of the genes in the medication groups showed an upward trend. Comparing 48 h with 72 h and 24 h with 72 h, the gene expression levels also increased, reaching a very significant difference (P<0.001), and there was a certain time dependence. CBP injection significantly reduced the expression of the Bcl-2 protein and induced apoptosis of Raji cells in a time-dependent manner. Moreover, CBP injection can increase the expression levels of the Bax and caspase-3 genes.