Abstract
Altered gene expression during breast tumour progression can occur through alternative splicing of mRNAs. The SR proteins have been identified as important factors in RNA splicing and in the incorporation of alternative exons in experimental systems. We have studied SR protein expression by western blot in human breast cell lines and in a cohort of 101 invasive breast tumours to examine the relationship with alternatively spliced isoforms of the CD44 gene. Multiple SR proteins (SR75, 55, 40, 30) were expressed in most cell lines and tumours, and their relative expression was independent of grade, size, or nodal status. Higher relative expression of SR55 protein was associated with an altered pattern of CD44 variants incorporating exon v7 (p = 0.047) as determined by reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot analysis. Nevertheless, transient transfection of MCF7 and HBL100 breast cell lines with SR55 had no direct effect on the expression of CD44 v7 variant expression. We conclude that while SR proteins may be important and necessary factors in mRNA splicing, other factors are also necessary to influence the regulation of alternatively spliced isoforms of CD44.
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Murphy LC, Dotzlaw H, Leygue E, Coutts A, Watson P: The pathophysiological role of estrogen receptor variants in human breast cancer. J Steroid Biochem Mol Biol 65: 175–180, 1998
Huang A, Leygue E, Dotzlaw H, Murphy LC, Watson PH: Influence of estrogen receptor variants on the determination of ER status in human breast cancer. Breast Cancer Res Treat 58: 219–225, 1999
Hole AK, Belkhiri A, Snell LS, Watson PH: CD44 variant expression and estrogen receptor status in breast cancer. Breast Cancer Res Treat 43: 165–173, 1997
Wang C, Thor AD, Moore DH, Zhao Y, Kerschmann R, Stern R, Watson PH, Turley EA: The overexpression of RHAMM, a hyaluronan-binding protein that regulates ras signaling, correlates with overexpression of mitogen-activated protein kinase and is a significant parameter in breast cancer progression. Clin Cancer Res 4: 567–576, 1998
Sharp PA: RNA splicing and genes. JAMA 260: 3035–3041, 1988
Hastings ML, Krainer AR: Pre-mRNA splicing in the new millennium. Curr Opin Cell Biol 13: 302–309, 2001
Fu XD, Maniatis T: Isolation of a complementary DNA that encodes the mammalian splicing factor SC35. Science 256: 535–538, 1992
Screaton GR, Caceres JF, Mayeda A, Bell MV, Plebanski M, Jackson DG, Bell JI, Krainer AR: Identification and characterization of three members of the human SR family of pre-mRNA splicing factors. EMBO J 14: 4336–4349, 1995
Graveley BR: Sorting out the complexity of SR protein functions. RNA 6: 1197–1211, 2000
Manley JL, Tacke R: SR proteins and splicing control. Genes Dev 10: 1569–1579, 1996
Zahler AM, Neugebauer KM, Lane WS, Roth MB: Distinct functions of SR proteins in alternative pre-mRNA splicing. Science 260: 219–222, 1993
Hofmann M, Rudy W, Zoller M, Tolg C, Ponta H, Herrlich P, Gunthert U: CD44 splice variants confer metastatic behavior in rats: homologous sequences are expressed in human tumor cell lines. Cancer Res 51: 5292–5297, 1991
Hiller T, Snell L, Watson PH: Microdissection RT-PCR analysis of gene expression in pathologically defined frozen tissue sections. Biotechniques 21: 38–40, 42, 44, 1996
Watson PH, Snell L, Parisien M: The NCIC-Manitoba Breast Tumor Bank: a resource for applied cancer research. CMAJ 155: 281–283, 1996
Schagger H, von Jagow G: Tricine-sodium dodecyl sulfatepolyacrylamide gel electrophoresis for the separation of proteins in the range from 1 to 100 kDa. Anal Biochem 166: 368–379, 1987
Tanaka M, Herr W: Differential transcriptional activation by Oct-1 and Oct-2: interdependent activation domains induce Oct-2 phosphorylation. Cell 60: 375–386, 1990
Gunthert U: CD44: a multitude of isoforms with diverse functions. Curr Top Microbiol Immunol 184: 47–63, 1993
Zahler AM, Lane WS, Stolk JA, Roth MB: SR proteins: a conserved family of pre-mRNA splicing factors. Genes Dev 6: 837–847, 1992
Murphy LC, Leygue E, Dotzlaw H, Douglas D, Coutts A, Watson PH: Oestrogen receptor variants and mutations in human breast cancer. Ann Med 29: 221–234, 1997
Leygue E, Dotzlaw H, Watson PH, Murphy LC: Expression of estrogen receptor beta1, beta2, and beta5 messenger RNAs in human breast tissue. Cancer Res 59: 1175–1179, 1999
Leygue E, Dotzlaw H, Watson PH, Murphy LC: Altered expression of exon 6 deleted progesterone receptor variant mRNA between normal human breast and breast tumour tissues. Br J Cancer 80: 379–382, 1999
Sanford JR, Bruzik JP: Developmental regulation of SR protein phosphorylation and activity. Genes Dev 13: 1513–1518, 1999
Gui JF, Lane WS, Fu XD: A serine kinase regulates intracellular localization of splicing factors in the cell cycle. Nature 369: 678–682, 1994
Stickeler E, Kittrell F, Medina D, Berget SM: Stage-specific changes in SR splicing factors and alternative splicing in mammary tumorigenesis. Oncogene 18: 3574–3582, 1999
Ghigna C, Moroni M, Porta C, Riva S, Biamonti G: Altered expression of heterogenous nuclear ribonucleoproteins and SR factors in human colon adenocarcinomas. Cancer Res 58: 5818–5824, 1998
Bell MV, Cowper AE, Lefranc MP, Bell JI, Screaton GR: Influence of intron length on alternative splicing of CD44. Mol Cell Biol 18: 5930–5941, 1998
Graveley BR, Hertel KJ, Maniatis T: A systematic analysis of the factors that determine the strength of pre-mRNA splicing enhancers. EMBO J 17: 6747–6756, 1998
Schaal TD, Maniatis T: Selection and characterization of premRNA splicing enhancers: identification of novel SR proteinspecific enhancer sequences. Mol Cell Biol 19: 1705–1719, 1999
Cowper AE, Caceres JF, Mayeda A, Screaton GR: Serinearginine (SR) protein-like factors that antagonize authentic SR proteins and regulate alternative splicing. J Biol Chem 276: 48908–48914, 2001
Du C, McGuffin ME, Dauwalder B, Rabinow L, Mattox W: Protein phosphorylation plays an essential role in the regulation of alternative splicing and sex determination in Drosophila. Mol Cell 2: 741–750, 1998
Xiao SH, Manley JL: Phosphorylation of the ASF/SF2 RS domain affects both protein-protein and protein-RNA interactions and is necessary for splicing. Genes Dev 11: 334–344, 1997
Nayler O, Stamm S, Ullrich A: Characterization and comparison of four serine-and arginine-rich (SR) protein kinases. Biochem J 326(Pt 3): 693–700, 1997
Rossi F, Labourier E, Forne T, Divita G, Derancourt J, Riou JF, Antoine E, Cathala G, Brunel C, Tazi J: Specific phosphorylation of SR proteins by mammalian DNA topoisomerase I. Nature 381: 80–82, 1996
Misteli T, Spector DL: Serine/threonine phosphatase 1 modulates the subnuclear distribution of pre-mRNA splicing factors. Mol Biol Cell 7: 1559–1572, 1996
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Pind, M.T., Watson, P.H. SR Protein Expression and CD44 Splicing Pattern in Human Breast Tumours. Breast Cancer Res Treat 79, 75–82 (2003). https://doi.org/10.1023/A:1023338718974
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DOI: https://doi.org/10.1023/A:1023338718974