Isolation and purification of novel peptides derived from Sepia ink: Effects on apoptosis of prostate cancer cell PC-3

Abstract

Novel prostate cancer therapeutics are in high demand. In order to identify potential therapeutic targets, protein from sepia ink was hydrolyzed by utilizing pepsin in an orthogonal array design. Pepsin hydrolysate (SH) obtained at optimal conditions exhibited the highest antitumor activity. Subsequently, a novel antitumor peptide, which was termed SHP, was isolated through ultrafiltration, gel filtration chromatography and reversed phase high‑performance liquid chromatography. The amino acid sequence of SHP was identified as Leu‑Lys‑Glu‑Glu‑Asn‑Arg‑Arg‑Arg‑Arg‑Asp with a molecular mass of 1371.53 Da. The results of the proliferation assay revealed that SHP significantly inhibited the proliferation of PC‑3 cells in a time‑ and dose‑dependent manner. Acridine orange/ethidium bromide staining indicated significant SHP‑induced apoptosis. Furthermore, Annexin V/PI double‑staining assays revealed that the percentage of early‑ stage apoptotic cells increased from 8.85 to 29% following PC‑3 exposure to 5, 10 and 15 mg/ml SHP for 24 h. SHP‑induced apoptosis was accompanied by the activation of cellular tumor antigen p53 and caspase‑3, the upregulation of apoptosis regulator BAX, and the downregulation of apoptosis regulator Bcl‑2. These findings suggest that SHP is a novel inducer of apoptosis in vitro and merits further investigation as a possible therapeutic agent for the treatment of cancer.

Purification and Characterization of a Novel Pentadecapeptide from Protein Hydrolysates of Cyclina sinensis and Its Immunomodulatory Effects on RAW264.7 Cells

“…Bioactive peptides (consisting of 2–20 amino acids) are protein fragments released from protein molecules via enzymatic hydrolysis and a series of refining processes, which harbor multiple bioactivities, including immunomodulatory [4], anti-inflammatory [5], antihypertensive [6,7,8], anticancer [9], antioxidant [10,11], and antifatigue [12] activities. Recently, several immunomodulatory peptides have been purified and identified from protein hydrolysates of natural origin [13].…”

Bioactive peptides from food fermentation: A comprehensive review of their sources, bioactivities, applications, and future development

“…It was found that the structurally modified QPK elicited all three apoptotic pathways (mitochondrial, death receptor, and endoplasmic reticulum stress induced) . In another study, Huang et al (2017) hydrolyzed sepia ink by pepsin to produce an antiproliferative peptide (LKEENRRRRD) acting against prostate PC-3 cells. The study showed that the resultant arginine-rich peptide was time and concentration dependent for cancer cell apoptosis.…”

“…In another study, Huang et al. (2017) hydrolyzed sepia ink by pepsin to produce an antiproliferative peptide (LKEENRRRRD) acting against prostate PC‐3 cells. The study showed that the resultant arginine‐rich peptide was time and concentration dependent for cancer cell apoptosis.…”

Recent Progress of Marine Polypeptides as Anticancer Agents

“…Study showed that the early-stage apoptotic cells of PC-3 were increased from 9% to 29% following exposure to 10-15 mg/mL SHP for 24 h by Annexin V/PI double-staining analysis. The apoptosis induced by SHP was accompanied by the down-regulation of apoptosis regulator Bcl-2, up-regulation of apoptosis regulator Bax and activation of caspase-3 and p53 [33]. A cyclomimetic peptide based on SHP, called SIO, was designed by introducing a disulfide bond to stabilize the native peptide.…”