The ethanol extract of Cyperus exaltatus var. iwasakii exhibits cell cycle dysregulation, ERK1/2/p38 MAPK/AKT phosphorylation, and reduced MMP-9-mediated metastatic capacity in prostate cancer models in vitro and in vivo

Abstract

Background: Prostate cancer is the second most common cause of cancer death worldwide in men. The development of novel and highly efficient therapeutic strategies is strongly recommended to treat prostate cancer. Cyperaceae are an ecologically and economically important family of plants with several pharmacological effects. However, the biological efficacy of Cyperus exaltatus var. iwasakii (CE) is unknown.

Purpose: This study aimed to investigate the antitumor effect of the ethanol extract of CE against prostate cancer.

Methods: In vitro antitumor efficacy of CE was explored by the MTT assay, cell counting assay, FACS analysis, immunoblot, wound-healing migration, invasion assay, zymographic assay, and EMSA in prostate cancer cells, DU145 and LNCaP. For in vivo experiments, xenograft mice were injected with LNCaP cells. Histology (H&E and Ki-67) and biochemical enzyme assay were then performed. The toxicity test was evaluated by an acute toxicity assay. The phytochemical constituents of CE were identified by spectrometric and chromatographic analyses.

Results: CE exerted a significant antiproliferative effect against prostate cancer cells. CE-induced antiproliferative cells were associated with cell cycle arrest at G₀/G₁ (cyclin D1/CDK4, cyclin E/CDK2, p21^Waf1) in DU145 cells, but G₂/M (ATR, CHK1, Cdc2, Cdc25c, p21^Waf1, and p53) in LNCaP cells. CE stimulated the phosphorylation of ERK1/2, p38 MAPK, and AKT in DU145 cells, but only p38 MAPK phosphorylation was increased in LNCaP cells. CE treatment suppressed migration and invasion in the two types of prostate cancer cells by inhibiting MMP-9 activity through the regulation of transcription factors, such as AP-1 and NF-κB. In vivo experiments showed a reduction in tumor weight and size following oral CE administration. Histochemistry confirmed that CE inhibited tumor growth in the mouse LNCaP xenograft model. The administration of CE had no adverse effects on body weight, behavioral patterns, blood biochemistry, and histopathology findings of vital organs in mice. Finally, a total of 13 phytochemical constituents were identified and quantified in CE. The most abundant secondary metabolites in CE were astragalin, tricin, and p-coumaric acid.

Conclusion: Our results demonstrated the antitumor efficacy of CE against prostate cancer. These findings suggest that CE might be a potential candidate for prostate cancer prevention or treatment.

Keywords: Invasion; Migration; Proliferation; Prostate cancer; Secondary metabolite; Xenograft mice.