Proteomic investigation of anti‐tumor activities exerted by sinularin against A2058 melanoma cells

Abstract

The extracts from soft corals have been increasingly investigated for biomedical and therapeutic purposes. The aim of this study is to examine and analyze the anti-tumor effects of the genus Sinularia extract sinularin on A2058 melanoma cells using MTT assay, cell migration assay, wound healing assay, flow cytometric analysis, and proteomic analysis. Sinularin dose-dependently (1-5 μg/mL) inhibited melanoma cell proliferation while the treatment at identical concentrations suppressed cell migration. Sinularin dose-dependently enhanced apoptotic melanoma cells and caused tumor cell accumulation at G2/M phase, indicating that sinularin exerts apoptosis-induced and cell cycle-delayed activities in A2058 melanoma cells. Comparative proteomic analysis was conducted to investigate the effects of sinularin at the molecular level by comparison between the protein profiling of melanoma cells treated with sinularin and without the treatment. Thirty-five differential proteins (13 upregulated and 22 downregulated) concerning the treatment were identified by liquid chromatography-tandem mass spectrometry. Proteomic data and Western blot displayed the levels of several tumor inhibitory or apoptosis-associated proteins including annexin A1, voltage-dependent anion-selective channel protein 1 and prohibitin (upregulated), heat shock protein 60, heat shock protein beta-1, and peroxiredoxin-2 (downregulated) in A2058 melanoma cells exposed to sinularin. Increased expression of p53, cleaved-caspase-3, cleaved-caspase-8, cleaved-caspase-9, p21, and Bax and decreased expression of Bcl-2 in sinularin-treated melanoma cells suggest that the anti-tumor activities of sinularin against melanoma cells are particularly correlated with these pro-apoptotic factors. These data provide important information for the mechanisms of anti-tumor effects of sinularin on melanoma cells and may be helpful for drug development and progression monitoring of human melanoma.

Improvement and enhancement of antibladder carcinoma cell effects of heteronemin by the nanosized hyaluronan aggregation

“…2,9,24 The concentrations of protein were determined by bicinchoninic acid assay according to the manufacturer's instructions. In all, 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis was used to run and separate the protein samples.…”

“…It has been found that several natural compounds from soft corals have cytotoxic and apoptosis-inducing effects against melanoma cells, hepatocellular carcinoma cells, and bladder cancer cells in our previous studies. 2,9,10 Heteronemin (HET) is a known sesterterpenoid extracted from the sponge Hippospongia sp. This natural marine compound was found to inhibit the enzyme protein farnesyltransferase and reduce the viability of leukemia cells, colon cancer cells, and breast cancer cells.…”

“…The experiment was performed in triplicate. 9,24 Flow cytometric analysis Apoptosis and cell cycle distribution of pure HET-or HA/ HET or CHI/HET aggregates-treated T24 bladder carcinoma cells were quantitated using a flow cytometer (BD LSR II; BD Biosciences). The cells were exposed to various treatments for 24 hours.…”

“…[28][29][30] Natural compounds extracted from marine soft corals have been shown to display apoptotic effects against tumor cells via the ER stress-related pathways. 9,10 The start of ER stress is usually a result from affecting ER homeostasis and interfering with proper protein folding, followed by imbalance between protein folding load and capacity, leading to eventual accumulation of unfolded/misfolded proteins in ER lumens that elicit unfolded protein response and ER-associated protein degradation. 9,29 Several crucial ER stress-related pathways, including the PERK/eIF2α/ATF4/CHOP, ATF6/ CHOP, and IRE1α/CHOP, have been revealed to be able to induce apoptosis in cancer cells.…”

“…9,10 The start of ER stress is usually a result from affecting ER homeostasis and interfering with proper protein folding, followed by imbalance between protein folding load and capacity, leading to eventual accumulation of unfolded/misfolded proteins in ER lumens that elicit unfolded protein response and ER-associated protein degradation. 9,29 Several crucial ER stress-related pathways, including the PERK/eIF2α/ATF4/CHOP, ATF6/ CHOP, and IRE1α/CHOP, have been revealed to be able to induce apoptosis in cancer cells. 9,10,29 Our Western blot results showed that treatment with pure HET results in increases in p-PERK, p-eIF2α, ATF4, IRE1α, and CHOP and a decrease in eIF2α, suggesting that HET is capable of eliciting apoptosis via several ER stress-associated pathways in bladder carcinoma cells.…”