ALA‐A2 Is a Novel Anticancer Peptide Inspired by Alpha‐Lactalbumin: A Discovery from a Computational Peptide Library, In Silico Anticancer Peptide Screening and In Vitro Experimental Validation

Abstract

Anticancer peptides (ACPs) are rising as a new strategy for cancer therapy. However, traditional laboratory screening to find and identify novel ACPs from hundreds to thousands of peptides is costly and time consuming. Here, a sequential procedure is applied to identify candidate ACPs from a computer‐generated peptide library inspired by alpha‐lactalbumin, a milk protein with known anticancer properties. A total of 2688 distinct peptides, 5–25 amino acids in length, are generated from alpha‐lactalbumin. In silico ACP screening using the physicochemical and structural filters and three machine learning models lead to the top candidate peptides ALA‐A1 and ALA‐A2. In vitro screening against five human cancer cell lines supports ALA‐A2 as the positive hit. ALA‐A2 selectively kills A549 lung cancer cells in a dose‐dependent manner, with no hemolytic side effects, and acts as a cell penetrating peptide without membranolytic effects. Sequential window acquisition of all theorical fragment ions‐proteomics and functional validation reveal that ALA‐A2 induces autophagy to mediate lung cancer cell death. This approach to identify ALA‐A2 is time and cost‐effective. Further investigations are warranted to elucidate the exact intracellular targets of ALA‐A2. Moreover, these findings support the use of larger computational peptide libraries built upon multiple proteins to further advance ACP research and development.

Virtual Screening of Peptide Libraries: The Search for Peptide-Based Therapeutics Using Computational Tools

“…ACPs can also be identified from virtual peptide libraries with computational techniques not including molecular docking. For instance, a peptide from the milk protein alpha-lactalbumin with cytotoxic activity on A549 lung cancer cells was identified using machine learning methods as a virtual screening approach to identify peptides with relevant physicochemical and anticancer properties [165].…”

Placenta-derived Extracellular Vesicles in Maternal Plasma of Hb Bart’s Fetuses

“…SWATH proteomics was performed as our previous studies [107,108,109] . Brie y, 50 µl of EVs were lysed in Laemmli's buffer (62.5 mM Tris-HCl, pH 6.8, 10% (v/v) glycerol, 2% (w/v) SDS and 2.5% (v/v) beta-mercaptoethanol).…”

Prophylactic Effect in the Gut Microbiota After Oral Administration of HAMLET: Results of a Case Control Study

“…Recent studies with peptides from alpha-LA [36,37] represent a hope and encourage for bladder cancer cells which usually therapeutic treatments has been failure or high rate of recurrence.. Taking advantage and the knowledge of the fact that partially unfolded alpha-LA, what is called the molten globular state, forms the oleic acid complex or HAMLET, with potent tumoricidal activity [36,37].…”

“…This complex in the placebo controlled, double blinded Phase I/II interventional clinical trial of non-muscle invasive bladder cancer reached safety and efficacy. Furthermore, the treated tumors show evidence of apoptosis and the expression of cancer-related genes is inhibited [37].…”