title: Identification of Smyd4 as a potential tumor suppressor gene involved in breast cancer development.
abstract: To identify genes involved in breast tumorigenesis, we applied the retroviral LoxP-Cre system to a nontumorigenic mouse mammary epithelial cell line NOG8 to create random chromosome deletion/translocation. We found that the disruption of one allele of Smyd4 (SET and MYND domain containing 4) gene through chromosome translocation led to tumorigenesis. The expression of Smyd4 was markedly decreased in tumor cells. Re-expression of Smyd4 resulted in growth suppression of tumor cells and inhibition of tumor formation in nude mice. Furthermore, the RNA interference-mediated suppression of Smyd4 expression in human MCF10A mammary epithelial cells caused their growth in soft agar. Microarray studies revealed that platelet-derived growth factor receptor alpha polypeptide (Pdgfr-alpha) was highly expressed in tumor cells compared with NOG8 cells. Re-expression of Smyd4 significantly reduced the expression of Pdgfr-alpha in tumor cells. In human breast cancers, reverse transcription-PCR results revealed that Smyd4 expression was totally silenced in 2 of 10 specimens. These findings indicate that Smyd4, as a potential tumor suppressor, plays a critical role in breast carcinogenesis at least partly through inhibiting the expression of Pdgfr-alpha, and could be a novel target for improving treatment of breast cancer.
authors.affiliation: Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611-3008, USA.
authors.forename: Liping
authors.initials: L
authors.lastname: Hu
authors.forename: Yiwei Tony
authors.initials: YT
authors.lastname: Zhu
authors.forename: Chao
authors.initials: C
authors.lastname: Qi
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Zhu
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D048708:Cell Growth Processes / Q000235:genetics; D045744:Cell Line, Tumor; D002886:Chromosomes, Human, Pair 17; D015870:Gene Expression; D020868:Gene Silencing; D016147:Genes, Tumor Suppressor; D006801:Humans; D034622:RNA Interference; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000096:biosynthesis / Q000235:genetics; D014178:Translocation, Genetic; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis / Q000235:genetics
chemical_list: C541944:Smyd4 protein, mouse; D025521:Tumor Suppressor Proteins; D020796:Receptor, Platelet-Derived Growth Factor alpha