Vernonia amygdalina Delile Induces Apoptotic Effects of PC3 Cells: Implication in the Prevention of Prostate Cancer

Abstract

Background: Prostate cancer (PCa) is one of the common cancers in males and its incidence keeps increasing globally. Approximately 81% of PCa is diagnosed during the early stage of the disease. The treatment options for prostate care include surgery, radiotherapy, and chemotherapy, but these treatments often have side effects that may lead to issues such as impotence or decreased bowel function. Our central goal is to test the apoptotic effects of Vernonia amygdalina Delile (an edible medicinal plant that is relatively inexpensive, nontoxic, and virtually without side effects) for the prevention of PCa using human adenocarcinoma (PC-3) cells as a test model.

Methods: To address our central goal, PC-3 cells were treated with Vernonia amygdalina Delile (VAD). Cell cycle arrest and cell apoptosis were evaluated by Flow Cytometry assessment. Nucleosomal DNA fragmentation was detected by agarose gel electrophoresis.

Results: Flow cytometry data showed that VAD induced cell cycle arrest at the G0/G1 checkpoint and significantly upregulated caspase-3 in treated cells compared to the control cells. Agarose gel electrophoresis resulted in the formation of DNA ladders in VAD-treated cells.

Conclusions: These results suggest that inhibition of cancer cell growth, induction of cell cycle arrest, and apoptosis through caspase-3 activation and nucleosomal DNA fragmentation are involved in the therapeutic mechanisms of VAD as a candidate drug towards the prevention and/or treatment of PCa.

Keywords: DNA fragmentation; Vernonia amygdalina Delile; apoptosis; cell cycle arrest; prostate cancer.

Figure 1:

Vernonia amygdalina Delile (VAD) triggered cell cycle arrest in PC-3 cells at the G0/G1 checkpoint. Both dot plots and histograms show the cell cycle distribution of PC-3 cells untreated and treated cells with VAD. Cells were stained with propidium iodide and analyzed by flow cytometry (FACS Calibar; Beton-Dickinson) using CellQuest software. A = Control (untreated), B = 125 μg/mL VAD, C = 250 μg/mL VAD, and D = 500 μg/mL VAD.

Figure 2:

VAD induced cell cycle arrest in human prostate cancer (PC-3) cells. PC-3 cells were treated with VAD at the concentrations of 125, 250, and 500 μg/mL for 48 hours. The cells were stained with propidium iodide and analyzed by the flow cytometry. Each experiment was performed three times for re-productivity. Data are expressed as Mean ± SD (n = 3). *Significantly different from the control by anova Dunnett’s test; P < 0.05.

Figure 3:

Representative flow cytometry analysis data from the active caspase-3 assay. The histograms show the distribution of caspase-3 negative cells (M1) and caspase-3 positive cells (M2) after 48 h treatment with VAD. A-control; B-125 μg/mL; C- 250 μg/mL; and D-500 μg/mL.

Figure 4:

Vernonia amygdalina Delile (VAD) induced nucleosomal DNA fragmentation in PC-3 cells. The cells were treated with VAD crude extract at 0 μg/mL, 125 μg/mL, 250 μg/mL, and 500 μg/mL. After treatment, cells were harvested and the oligonucleosomal DNA fragments were isolated, separated by agarose gel electrophoresis and analyzed as described in the materials and methods.