Cancer-preventive peptide lunasin from Solanum nigrum L. inhibits acetylation of core histones H3 and H4 and phosphorylation of retinoblastoma protein (Rb).
Lunasin, a unique 43 amino acid, 4.8 kDa cancer-chemopreventive peptide initially reported in soybean and now found in barley and wheat, has been shown to be cancer-chemopreventive in mammalian cells and in a skin cancer mouse model against oncogenes and chemical carcinogens. To identify bioactive components in traditional herbal medicines and in search for new sources of lunasin, we report here the properties of lunasin from Solanum nigrum L. (SNL), a plant indigenous to northeast Asia. Lunasin was screened in the crude extracts of five varieties of the medicinal plants of Solanaceae origin and seven other major herbal plants. An in vitro digestion stability assay for measuring bioavailability was carried out on SNL crude protein and autoclaved SNL using pepsin and pancreatin. A nonradioactive histone acetyltransferase (HAT) assay and HAT activity colorimetric assay were used to measure the inhibition of core histone acetylation. The inhibitory effect of lunasin on the phosphorylation of retinoblastoma protein (Rb) was determined by immunoblotting against phospho-Rb. Lunasin isolated from autoclaved SNL inhibited core histone H3 and H4 acetylation, the activities of the HATs, and the phosphorylation of the Rb protein. Lunasin in the crude protein and in the autoclaved crude protein was very stable to pepsin and pancreatin in vitro digestion, while the synthetic pure lunasin was digested at 2 min after the reaction. We conclude that lunasin is a bioactive and bioavailable component in SNL and that consumption of SNL may play an important role in cancer prevention.
Jeong
Jin Boo
JB
School of Bioresources Sciences, Andong National University, Korea.
Jeong
Hyung Jin
HJ
Park
Jae Ho
JH
Lee
Sun Hee
SH
Lee
Jeong Rak
JR
Lee
Hee Kyeong
HK
Chung
Gyu Young
GY
Choi
Jeong Doo
JD
de Lumen
Ben O
BO
D000107:Acetylation / Q000187:drug effects; D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D004355:Drug Stability; D006657:Histones / Q000378:metabolism*; D051379:Mice; D041681:NIH 3T3 Cells; D010194:Pancreatin / Q000378:metabolism; D010434:Pepsin A / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010940:Plant Proteins / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology*; D016160:Retinoblastoma Protein / Q000378:metabolism*; D032324:Solanum nigrum / Q000737:chemistry*
D016588:Anticarcinogenic Agents; D006657:Histones; D010940:Plant Proteins; D016160:Retinoblastoma Protein; D010194:Pancreatin; D010434:Pepsin A