title: Proteomic Analysis and Functional Studies of Baicalin on Proteins Associated with Skin Cancer.
abstract: Abundant evidence supports the key role of ultraviolet radiation (UVR) in skin cancer development. The human skin, especially the epidermal layer, is the main defense against UV radiation. Baicalin is a major bioactive component of Scutellaria baicalensis Georgi, a plant which has been found to exhibit antitumor activity. The anticarcinogenic mechanism of baicalin is not completely understood. We have reported that baicalin inhibited UVB-induced photo-damage and apoptosis in HaCaT cells (human skin keratinocytes). The aim of the present study is to investigate the cellular gene targets responsible for baicalin's antitumor activity by performing two-dimensional electrophoresis liquid chromatography-mass spectrometry/mass spectrometry (2-DE LC-MS/MS) with HaCaT cells following UVB and baicalin exposure. Two-DE for protein separation was performed, followed by matrix-assisted laser desorption/ionization mass spectrometry and database searches. Nucleophosmin (NPM)-specific siRNA was designed and synthesized, and the small interfering RNA was transfected into skin squamous cancer A431 cells to knockdown the NPM expression. Proliferation and cell cycle status were assessed by CCK8 and flow cytometric analyses, respectively. We have identified 38 protein spots that are differentially expressed in HaCaT cells exposed to baicalin and/or UVB irradiation These proteins are involved in detoxification, proliferation, metabolism, cytoskeleton and motility. In particular, we found several proteins that have been linked to tumor progression and resistance, such as NPM. Baicalin treatment reduced the cellular proliferation rate and induced arrest during the S-phase of the cell cycle in A431 cells. NPM1 silencing significantly enhanced the effect of baicalin. Our data indicated that baicalin results in the significant inhibition of tumor growth in the A431 cell line, which may be associated with the regulation of the NPM gene expression.
authors.affiliation: * Department of Dermatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China.
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.affiliation: * Department of Dermatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China.
authors.forename: Bingjiang
authors.initials: B
authors.lastname: Lin
authors.affiliation: ‡ Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, AL, USA.
authors.forename: Nabiha
authors.initials: N
authors.lastname: Yusuf
authors.affiliation: ‡ Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, AL, USA.
authors.forename: Erin M
authors.initials: EM
authors.lastname: Burns
authors.affiliation: † Department of Dermatology, The First Affiliated Hospital of Soochow University, Suzhou, P.R. China.
authors.forename: Xiuqin
authors.initials: X
authors.lastname: Yu
authors.affiliation: * Department of Dermatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China.
authors.forename: Dan
authors.initials: D
authors.lastname: Luo
authors.affiliation: † Department of Dermatology, The First Affiliated Hospital of Soochow University, Suzhou, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Min
mesh_terms: D000972:Antineoplastic Agents, Phytogenic; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000187:drug effects; D005419:Flavonoids / Q000235:genetics* / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D058990:Molecular Targeted Therapy; D000090243:Nucleophosmin; D008517:Phytotherapy; D040901:Proteomics; D034622:RNA Interference / Q000187:drug effects; D034741:RNA, Small Interfering; D031364:Scutellaria baicalensis / Q000737:chemistry; D012878:Skin Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology*; D014407:Tumor Cells, Cultured
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D005419:Flavonoids; C000716967:NPM1 protein, human; D034741:RNA, Small Interfering; D000090243:Nucleophosmin; C038044:baicalin
keywords: Baicalin; Keratinocyte HaCaT cells; NPM; Proteomics; Skin; Squamous Cancer A431 cells; UVB