title: Simultaneous siRNA targeting of Src and downstream signaling molecules inhibit tumor formation and metastasis of a human model breast cancer cell line.
abstract: BACKGROUND
  Src and signaling molecules downstream of Src, including signal transducer and activator of transcription 3 (Stat3) and cMyc, have been implicated in the development, maintenance and/or progression of several types of human cancers, including breast cancer. Here we report the ability of siRNA-mediated Src knock-down alone, and simultaneous knock-down of Src and Stat3 and/or cMyc to inhibit the neoplastic phenotype of a highly metastatic human model breast cancer cell line, MDA-MB-435S, a widely used model for breast cancer research.
  
  
  RESULTS
  Src and its downstream signaling partners were specifically targeted and knocked-down using siRNA. Changes in the growth properties of the cultured cancer cells/tumors were documented using assays that included anchorage-dependent and -independent (in soft agar) cell growth, apoptosis, and both primary and metastatic tumor growth in the mouse tumor model. siRNA-mediated Src knock-down alone, and simultaneous knock-down of Src and Stat3 and/or cMyc inhibited the neoplastic phenotype of a highly metastatic human model breast cancer cell line, MDA-MB-435S. This knock-down resulted in reduced growth in monolayer and soft agar cultures, and a reduced ability to form primary tumors in NOD/SCID mice. In addition, direct intra-tumoral injection of siRNAs targeting these signaling molecules resulted in a substantial inhibition of tumor metastases as well as of primary tumor growth. Simultaneous knock-down of Src and Stat3, and/or Myc exhibited the greatest effects resulting in substantial inhibition of primary tumor growth and metastasis.
  
  
  CONCLUSIONS
  These findings demonstrate the effectiveness of simultaneous targeting of Src and the downstream signaling partners Stat3 and/or cMyc to inhibit the growth and oncogenic properties of a human cancer cell line. This knowledge may be very useful in the development of future therapeutic approaches involving targeting of specific genes products involved in tumor growth and metastasis.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Bjorge
authors.forename: Andy S
authors.initials: AS
authors.lastname: Pang
authors.forename: Melanie
authors.initials: M
authors.lastname: Funnell
authors.forename: Ke Yun
authors.initials: KY
authors.lastname: Chen
authors.forename: Roman
authors.initials: R
authors.lastname: Diaz
authors.forename: Anthony M
authors.initials: AM
authors.lastname: Magliocco
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Fujita
mesh_terms: D000818:Animals; D017209:Apoptosis; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D008055:Lipids; D051379:Mice; D016513:Mice, SCID; D009362:Neoplasm Metastasis; D011230:Precancerous Conditions / Q000378:metabolism / Q000473:pathology*; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism*; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction; D023041:Xenograft Model Antitumor Assays
chemical_list: D008055:Lipids; D016271:Proto-Oncogene Proteins c-myc; D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor; C484027:oligofectamine; D016392:Proto-Oncogene Proteins pp60(c-src)