title: The Alternative Splicing of Cytoplasmic Polyadenylation Element Binding Protein 2 Drives Anoikis Resistance and the Metastasis of Triple Negative Breast Cancer.
abstract: Triple negative breast cancer (TNBC) represents an anomalous subset of breast cancer with a greatly reduced (30%) 5-year survival rate. The enhanced mortality and morbidity of TNBC arises from the high metastatic rate, which requires the acquisition of AnR, a process whereby anchorage-dependent cells become resistant to cell death induced by detachment. In this study TNBC cell lines were selected for AnR, and these cell lines demonstrated dramatic enhancement in the formation of lung metastases as compared with parental cells. Genetic analysis of the AnR subclones versus parental cells via next generation sequencing and analysis of global alternative RNA splicing identified that the mRNA splicing of cytoplasmic polyadenylation element binding 2 (CPEB2), a translational regulator, was altered in AnR TNBC cells. Specifically, increased inclusion of exon 4 into the mature mRNA to produce the CPEB2B isoform was observed in AnR cell lines. Molecular manipulations of CPEB2 splice variants demonstrated a key role for this RNA splicing event in the resistance of cells to anoikis. Specifically, down-regulation of the CPEB2B isoform using siRNA re-sensitized the AnR cell lines to detachment-induced cell death. The ectopic expression of CPEB2B in parental TNBC cell lines induced AnR and dramatically increased metastatic potential. Importantly, alterations in the alternative splicing of CPEB2 were also observed in human TNBC and additional subtypes of human breast cancer tumors linked to a high metastatic rate. Our findings demonstrate that the regulation of CPEB2 mRNA splicing is a key mechanism in AnR and a driving force in TNBC metastasis.
authors: From the Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond Virginia 23298.
authors: Ryan M
authors: RM
authors: Johnson
authors: From the Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond Virginia 23298, Vietnam Education Foundation, Arlington, Virginia 22201.
authors: Ngoc T
authors: NT
authors: Vu
authors: From the Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond Virginia 23298.
authors: Brian P
authors: BP
authors: Griffin
authors: Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia 23298.
authors: Amanda E
authors: AE
authors: Gentry
authors: Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia 23298, Virginia Commonwealth University Massey Cancer Center Biostatistics Shared Resource, Richmond, Virginia 23298, Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia 23298.
authors: Kellie J
authors: KJ
authors: Archer
authors: From the Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond Virginia 23298, Virginia Commonwealth University Massey Cancer Center Massey Cancer Center, Richmond, Virginia 23298, Research and Development, Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia 23224, Virginia Commonwealth University Institute of Molecular Medicine, Richmond Virginia, 23298, and Virginia Commonwealth University Johnson Center, Richmond, Virginia, 23298 cechalfant@vcu.edu.
authors: Charles E
authors: CE
authors: Chalfant
authors: From the Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond Virginia 23298, Virginia Commonwealth University Massey Cancer Center Massey Cancer Center, Richmond, Virginia 23298, mpark4@vcu.edu.
authors: Margaret A
authors: MA
authors: Park
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D023102:Anoikis / Q000502:physiology*; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D051379:Mice; D016688:Mice, Inbred NOD; D009362:Neoplasm Metastasis; D012333:RNA, Messenger / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D064726:Triple Negative Breast Neoplasms / Q000378:metabolism* / Q000473:pathology
chemical_list: C554938:CPEB2 protein, human; D012333:RNA, Messenger; D016601:RNA-Binding Proteins
keywords: alternative splicing; anoikis; breast cancer; metastasis; translation control