Effect of holothuria polii extracts on prostate cancer cells -

Abstract

Background: The wealthy and unexplored biodiversity of the Mediterranean Sea has recently attracted the attention of scientists to explore novel bioactive compounds. Prostate cancer is the second most diagnosed cancer in men. Despite progress in the fields of treatment and diagnosis of this disease, incidence and mortality rates are still high.Aims: The aim of this study is to investigate the effect of the ethanolic sea cucumber (Holothuria polii) extract (SCE) and their fractionated material against the proliferation and metastasis of human prostate cancer cells. Their bioactivity is also assessed for targeting an enriched population of prostate cancer stem cells (CSCs).Methods: The effect of the crude SCE on the viability and proliferation was investigated using trypan blue exclusion assay, MTT assay and Real Time Cell Analysis (RTCA). Effect on cell cycle progression was studied on DNA content using Propidium Iodide (PI) by flow cytometer. Hoechst nuclear staining was performed to assess for apoptotic bodies as a proof of apoptosis. Immunofluorescence (IF) and western blotting (WB) were also performed on apoptotic markers. SCE effect on metastasis was further evaluated by invasion (RTCA, gelatin zymography) and migration assays (RTCA, wound healing). Real-time PCR, WB and IF were performed to assess the effect of SCE on the transcriptional and translational level and cellular localization of EMT markers, a pro-angiogenic factor and a metastatic marker. Sphere-formation assay was conducted to study the effect of SCE on targeting an enriched population of prostate CSCs. Finally, the potential of the aqueous SCE obtained from increased solvent polarity fractionation was also investigated on prostate cancer cells‟ proliferation using trypan blue exclusion assay, and on its ability to target prostate CSCs using sphere formation assay.Results: SCE inhibited the proliferation of two prostate cancer cells in a time- and dose- dependent manner. Cell cycle analysis revealed that SCE causes G0-G1 arrest and an in