title: Lunasin is a novel therapeutic agent for targeting melanoma cancer stem cells.
abstract: Recent studies provide compelling evidence that melanoma is initiated and maintained by a small population of malignant cells called cancer-initiating cells (CICs) that exhibit stem-cell-like properties. Observations that CICs have a distinct biology when compared to that of the bulk tumor cells and, importantly, are resistant to chemotherapies and radiation, suggest that CICs are involved in invasion, metastasis, and ultimately relapse. Lunasin, a bioactive peptide present in soybean, has both chemopreventive activity and chemotherapeutic activity against multiple cancer types. In this study, we tested the potential of Lunasin to specifically target CICs in melanoma tumor cell populations. In vitro studies using human melanoma cell lines showed that Lunasin treatment decreased the size of a subpopulation of melanoma cells expressing the surrogate CIC marker, Aldehyde Dehydrogenase, concomitant with a reduction in the ability to form colonies in soft agar assays, and reduced tumor growth in mouse xenografts. Similarly, Lunasin inhibited colony formation by isolated melanoma CICs in soft agar and reduced oncosphere formation in vitro and substantially inhibited tumor growth in mouse xenografts. Mechanistic studies revealed that Lunasin treatment of isolated melanoma CICs induced expression of the melanocyte-associated differentiation markers Tyrosinase and Microphthalmia-associated Transcription Factor concomitant with reduced expression of the stemness factor NANOG. These findings document for the first time that Lunasin has significant therapeutic activity against melanoma by specifically targeting melanoma CICs, and inducing a more differentiated, non-CIC phenotype. Thus, Lunasin may represent a novel therapeutic option for both chemoresistant and advanced metastatic melanoma management.
authors: Department of Pharmacology and Toxciology, University of Louisville School of Medicine, Louisville, Kentucky, USA.|James Graham Brown Cancer Center, University of Louisville School of Medicine, Louisville, Kentucky, USA.|Biotechnology Program, Indiana University, Bloomington, Indiana, USA.
authors: Chris
authors: C
authors: Shidal
authors: Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky, USA.|James Graham Brown Cancer Center, University of Louisville School of Medicine, Louisville, Kentucky, USA.
authors: Numan
authors: N
authors: Al-Rayyan
authors: Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky, USA.|James Graham Brown Cancer Center, University of Louisville School of Medicine, Louisville, Kentucky, USA.
authors: Kavitha
authors: K
authors: Yaddanapudi
authors: Biotechnology Program, Indiana University, Bloomington, Indiana, USA.
authors: Keith R
authors: KR
authors: Davis
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D008297:Male; D008545:Melanoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008819:Mice, Nude; D008954:Models, Biological; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D010940:Plant Proteins / Q000494:pharmacology*; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D010940:Plant Proteins; C556331:lunasin protein, barley; D000444:Aldehyde Dehydrogenase
keywords: MITF; NANOG; cancer stem cells; lunasin; melanoma