Abstract LB-131: Decreased nuclear localization and expression of the FRY tumor suppressor gene, a repressor of epithelial mesenchymal transition, are highly correlated with breast cancer phenotype, grade, and progression

Abstract

Abstract Using Quantitative Trait Locus (QTL) mapping in a backcross between susceptible Fischer 344 and resistant Copenhagen rat strains, we identified Fry, the rat ortholog of the Drosophila melanoganster furry gene, as a mammary carcinoma susceptibility (Mcs) gene. The Fischer 344 Fry allele harbors two single nucleotide polymorphisms that alter amino acid residues that are highly conserved from yeast to humans. One of these SNPs replaces an Alanine with a Serine residue, creating a de novo concensus sequence for several cancer-associated protein kinases. In the lower eucaryoyes, the furry orthologs are implicated in diverse cell processes including epithelial cell polarization, morphogenesis, proliferation, cytokinesis, and regulation of the NDR family of kinases, some of which are putative human tumor suppressor genes. Consistent with its function as a tumor suppressor gene, ectopic expression of the FRY gene was reduced in 3 of 4 human breast cancer cell lines. Ectopic expression of the wildtype allele significantly reduced the tumorigenicity of the human MDA-MB-231 mammary carcinoma cell line. In contrast to the parental MDA-MB-231 cells, which grew randomly in Matrigel® matrix, those expressing Fry (231CFry) formed spherical colonies of differentiated cells, closely resembling those formed by MCF-10A normal mammary epithelial cell line. When xenographed into nude mice, the 231CFry cells demonstrated a dramatic reduction in tumorigenicity (8x reduction in tumor volume at 15 days) and diminished invasiveness into surrounding tissues. Gene expression profiling suggested that in MDA-MB-231 cells, ectopic Fry induced the expression of gene networks involved in cell differentiation, proliferation, and polarization, consistent with a role for FRY in suppressing epithelial-mesenchymal transition (EMT). To investigate the role of human FRY in breast cancer, we examined FRY mRNA expression in >1,500 human breast cancers, representing distinct eight cohorts entered into the Oncomine 3.0 Cancer Profiling Database. Our analysis revealed that decreased FRY mRNA was highly correlated with poorly differentiated breast cancer phenotypes (p<0.0001), increasing Elston tumor grade (p<0.0001) and clinically aggressive cancer phenotypes (p<0.05). Using an anti-FRY peptide antiserum, we examined FRY protein expression in cores comprising the BR208 breast cancer and tissue microarrays from US Biomax, Inc. Immunohistochemical staining patterns were analyzed by quantitative image analysis software and independently by a board certified pathologist. The analyses indicated that decreased nuclear localization and expression of FRY were highly correlated with histopathology, clinical grade and progression, indicating that the FRY tumor suppressor is an important new biomarkers of breast cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-131. doi:10.1158/1538-7445.AM2011-LB-131