Hair from two donors, a gray-haired elderly man and a young brunette woman, were collected after a haircut and separately processed by activation in sodium hydroxide prior to digestion with pepsin, a protease that cleaves at the C-terminus of phenylalanine, leucine, tyrosine and tryptophan. The digested fragments were extracted, frozen and dried down. The remaining unsolubilized material was dried, ground and redigested with pepsin, yielding two samples of pepsin digests from each hair sample. The final pepsin digests were suspended in 70% ethanol.
The soluble peptide mixture (0.001–0.1% [m/v]) was applied to early- and late-passage melanoma cell lines (with and without exposure to gamma irradiation), and cell proliferation assessed. For all three melanoma cell lines tested (MeW100, MeW187 and FTSLC), the hair peptides reduced proliferation with the greatest reduction at 0.1%. The antiproliferative effect was seen in multiple melanoma cell lines regardless of which hair digestion sample was used.
What about other cancer cell lines? Markowicz et al. also tested urinary bladder cancer T24 cells and B cell lymphoma lines Namalwa and DOHH-2 with similar reduced proliferation. In comparison, there was no effect of either pepsin-digested hair donor sample on normal human mesenchymal umbilical cord cells but some reduced proliferation for human fibroblast lines Fib 9 and FlWp95. The proliferation of human fibroblast line FlW 180 was decreased only with the pepsin-digested sample from the gray-haired man.
This PLOS ONE article explored the idea that hair degradation products may have some anticancer effects. Researchers used melanoma and other cancer cell lines to demonstrate that pepsin-digested hair samples were able to reduce cell proliferation. This is a preliminary proof-of-concept that suggests there may be anticancer compounds derived from human hair.
Markowicz S., Kurzepa, D., Bochynska, M., Biernacka, M., Samluk, A., Dudek, D., Skurzak, H., Yoshikawa, M. and Lipkowski, A.W. (2014) Anticancer properties of peptide fragments of hair proteins, PLoS ONE, 9 (6) e98073. DOI: http://dx.doi.org/10.1371/journal.pone.0098073
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