title: CONSORT: Sam68 Is Directly Regulated by MiR-204 and Promotes the Self-Renewal Potential of Breast Cancer Cells by Activating the Wnt/Beta-Catenin Signaling Pathway.
abstract: Breast cancer stem cells (BCSCs) are considered to be responsible for recurrence in breast cancer. The 68 kDa Src-associated protein in mitosis (Sam68) has been linked to the development and progression of breast cancer; however, the posttranscriptional regulation and role of Sam68 in BCSC self-renewal remain unclear.Sam68 was ectopically overexpressed or knocked down using a siRNA; the self-renewal potential of breast cancer cell lines was assessed using flow cytometry, in vitro mammosphere culture and a xenograft model in NOD/SCID mice. Activation of beta-catenin was assessed by immunohistochemical staining, Western blotting, and luciferase reporter gene assays. The ArrayExpress dataset GSE45666 was used to identify conserved microRNAs downregulated in breast cancer; real-time PCR, Western blotting, luciferase reporter assay, and xenografted tumor model were used to confirm miR-204 regulated Sam68.We found that endogenous Sam68 expression correlated positively with the self-renewal potential of breast cancer cell lines. Overexpression of Sam68 promoted, whereas knockdown reduced, breast cancer cell self-renewal potential in vitro and tumorigenicity in vivo. The Wnt/beta-catenin pathway was identified as a functional mediator of Sam68-induced self-renewal in SKBR-3 and MCF-7 cells. Furthermore, miR-204 was found to be frequently downregulated in human breast cancer and confirmed to directly target Sam68; miR-204 inhibited the self-renewal of breast cancer cell lines by targeting and suppressing Sam68.Our study reveals that Sam68 is regulated by miR-204 and may play an important role in the self-renewal of BCSCs via activating the Wnt/beta-catenin pathway. Sam68 may represent a novel therapeutic target for breast cancer.
authors.affiliation: From the Department of Pathogen Biology and Immunology, School of Basic Courses, Guangdong Pharmaceutical University, Guangzhou, China (LW, HW); Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China (HT, XZ); and Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China (HT, JY, JW, XZ).
authors.forename: Lan
authors.initials: L
authors.lastname: Wang
authors.forename: Han
authors.initials: H
authors.lastname: Tian
authors.forename: Jie
authors.initials: J
authors.lastname: Yuan
authors.forename: Hongmei
authors.initials: H
authors.lastname: Wu
authors.forename: Jueheng
authors.initials: J
authors.lastname: Wu
authors.forename: Xun
authors.initials: X
authors.lastname: Zhu
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D000066673:Cell Self Renewal / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D061986:MCF-7 Cells; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D035683:MicroRNAs / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D060449:Wnt Signaling Pathway / Q000502:physiology*; D051176:beta Catenin / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; C504459:FILIP1L protein, human; D047908:Intracellular Signaling Peptides and Proteins; C489559:KHDRBS1 protein, human; C549404:MIRN204 microRNA, human; D035683:MicroRNAs; D016601:RNA-Binding Proteins; D051176:beta Catenin