A short hairpin DNA analogous to miR-125b inhibits C-Raf expression, proliferation, and survival of breast cancer cells.
The noncoding RNA miR-125b has been described to reduce ErbB2 protein expression as well as proliferation and migration of cancer cell lines. As additional target of miR-125b, we identified the c-raf-1 mRNA by sequence analysis. We designed a short hairpin-looped oligodeoxynucleotide (ODN) targeted to the same 3' untranslated region of c-raf-1 mRNA as miR-125b. The fully complementary ODN antisense strand is linked to a second strand constituting a partially double-stranded structure of the ODN. Transfection of the c-raf-1-specific ODN (ODN-Raf) in a breast cancer cell line reduced the protein levels of C-Raf, ErbB2, and their downstream effector cyclin D1 similar to miR-125b. MiR-125b as well as ODN-Raf showed no effect on the c-raf-1 mRNA level in contrast to small interfering RNA. Unlike miR-125b, ODN-Raf induced a cytopathic effect. This may be explained by the structural properties of ODN-Raf, which can form G-tetrads. Thus, the short hairpin-looped ODN-Raf, targeting the same region of c-raf-1 as miR-125b, is a multifunctional molecule reducing the expression of oncoproteins and stimulating cell death. Both features may be useful to interfere with tumor growth.
Hofmann
Marco H
MH
University of Zurich, Zurich, Switzerland.
Heinrich
Jochen
J
Radziwill
Gerald
G
Radziwil
Gerald
G
Moelling
Karin
K
D001943:Breast Neoplasms / Q000235:genetics* / Q000503:physiopathology / Q000628:therapy; D002277:Carcinoma / Q000235:genetics* / Q000503:physiopathology / Q000628:therapy; D016923:Cell Death / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics; D015536:Down-Regulation / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods; D006801:Humans; D055029:Inverted Repeat Sequences / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics*; D020319:Oligodeoxyribonucleotides, Antisense / Q000138:chemical synthesis / Q000235:genetics*; D019908:Proto-Oncogene Proteins c-raf / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics; D014162:Transfection / Q000379:methods*
D035683:MicroRNAs; D020319:Oligodeoxyribonucleotides, Antisense; D019908:Proto-Oncogene Proteins c-raf; D012333:RNA, Messenger; D018719:Erb-b2 Receptor Tyrosine Kinases; C531888:MIRN125 microRNA, human; C508053:ERBB2 protein, human