Preparation and characterization of fetal rat renal cell peptides for their antitumor activity

Abstract

Background The therapeutic efficacy of traditional chemotherapies and advanced targeted therapies is unsatisfactory due to systemic adverse effects. Bioactive peptides are attractive therapeutic reagents because of their high antitumor activity and safety profiles. Currently, antitumor bioactive peptides can be derived from various organisms. This study aimed to prepare and characterize fetal rat renal cell peptides (RCPs) for their antitumor activities in vitro. Methods The kidneys were dissected from fetal SD rats and digested with collagenase to obtain renal cells, which were further digested with trypsin, alkaline protease, papain, and protamex, respectively. Following filtration with 3 and 10-K filters, the enzyme-digested products were measured for protein concentrations and tested for their cytotoxicity against MCF-7 cells. The bioactive peptides in individual enzyme products were predicted using http://distilldeep.ucd.ie/PeptideRanker. The top predicted bioactive peptides were synthesized and tested for their cytotoxicity against different types of tumor cells in vitro by CCK-8 assays. Finally, their IC50 values were calculated and accuracy for antitumor activity was estimated by ROC curve. Results Digestion with collagenase resulted in renal cells with epithelial morphology and digestion of renal cells with trypsin, papain, protamex, or alkaline protease led to different percentages of products with a molecular weight of < 3k, 3-10k, or > 10k. Preliminary screening revealed that treatment with different concentrations of trypsin, papain, or protamex, but not alkaline protease-digested < 3k protein products reduced the viability of MCF-7 cells in a dose-dependent manner. Functionally, many bioactive peptides were predicted and the top ten peptides (RCPs 1–10) were synthesized. Interestingly, the RCP1, 5, and 6 displayed preferable cytotoxicity against human cancer MCF-7, A549, HCT-116, Hela, HepG2, and SGC-7901 cells and their cytotoxicity was time- and dose-dependent. Conclusion RCPs prepared from embryonic rat renal cells displayed potent cytotoxicity preferably against different types of cancer cells in vitro in a time- and dose-dependent manner. These peptides may be valuable for the treatment of malignant tumors.