title: Grifolin, a potential antitumor natural product from the mushroom Albatrellus confluens, induces cell-cycle arrest in G1 phase via the ERK1/2 pathway.
abstract: Grifolin, a natural product isolated from the mushroom Albatrellus confluens, has been shown to inhibit the growth of some cancer cell lines and induce significant apoptosis. However, the molecular targets and the signaling mechanism underlying the anticancer effect of this compound are not completely understood. Here, we undertook a gene expression profiling study to identify novel targets of grifolin. We found that the effect of grifolin on the human nasopharyngeal carcinoma cell line CNE1 occurs primarily via the ERK1/2 pathway. At high doses, both the ERK1/2 and the ERK5 pathways may be involved in the inhibition. Because inhibition of the ERK1/2 or the ERK5 pathway has been associated with cell-cycle arrest and growth inhibition, we evaluated the cell cycle distribution after grifolin treatment. We found that grifolin significantly caused cell-cycle arrest in G1 phase. To investigate the underlying mechanisms, G1-related proteins were assayed by Western blotting. Following grifolin treatment, a concomitant inhibition of cyclin D1, cyclin E, CDK4 expression, and subsequent reduction in pRB phosphorylation occurred. Meanwhile, grifolin treatment also resulted in a significant upregulation of CKI (p19INK4D). These results suggest that the inhibition of the ERK1/2 or the ERK5 pathway is responsible for at least part of the induction of cell-cycle arrest in G1 phase by grifolin. These results are significant in that they provide a mechanistic framework for further exploring the use of grifolin as a novel antitumor agent.
authors.affiliation: Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, Hunan 410078, PR China.
authors.forename: Mao
authors.initials: M
authors.lastname: Ye
authors.forename: Xiangjian
authors.initials: X
authors.lastname: Luo
authors.forename: Lili
authors.initials: L
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Shi
authors.forename: Ming
authors.initials: M
authors.lastname: Tan
authors.forename: Xinxian
authors.initials: X
authors.lastname: Weng
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Jikai
authors.initials: J
authors.lastname: Liu
authors.forename: Ya
authors.initials: Y
authors.lastname: Cao
mesh_terms: D000363:Agaricales / Q000737:chemistry*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001688:Biological Products / Q000494:pharmacology*; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects*; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D016193:G1 Phase / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D013729:Terpenes / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D001688:Biological Products; D018797:Cell Cycle Proteins; D013729:Terpenes; C058858:grifolin; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3