Abstract 5150: FJX1 is an important mediator of tumor biology due, in part, to its effect ontumor vascularization

Abstract

Abstract The underlying mechanisms responsible for tumor vascularization, often correlating with poor prognosis, are an important area of cancer research. We identified Four jointed box 1 (fjx1) as a candidate gene for regulating tumor vascularization in colorectal cancer (CRC) as it was inhibited in rectal cancers (n=16) after one week treatment with Celebrex. We hypothesized that FJX1 contributes to malignant cellular behavior by enhancing tumor vascularization. Using microarray data from 255 CRC patients we determined relative fjx1 mRNA expression levels across normal, adenoma, and stages I-IV CRC. Data were validated using quantitative RT-PCR on selected patient samples. Patients were segregated as having lower or higher than median fjx1 expression and Kaplan-Meier survival estimates were derived. Biological function was tested by overexpressing Myc-tagged human FJX1 protein in various cell lines (HEK293T, YAMC, SW480) and subjecting them to invasion and proliferation assays in vitro. SW480 derivatives were also used for flank injections to assess tumorigenesis in vivo. Tumors were analyzed via immunohistochemistry for markers of proliferation, apoptosis, and endothelial cells. Finally, conditioned media from SW480 derivatives was used in vitro to test the effects on endothelial cell (HMEC-1) invasion and tube formation. Microarray expression data from our 255 CRC patient data set showed that fjx1 mRNA is elevated in all stages of CRC as compared to normal/adenoma tissue. Higher expression of fjx1 relative to the median was associated with significantly worse overall patient survival (p=0.0125). Elevated mRNA expression from tumor samples as compared to normal was validated by qRT-PCR within a subset of patients. Over-expression of fjx1 in HEK293T, YAMC, and SW480 cells increased invasion in vitro without altering cell proliferation. Conditioned media from SW480FJX1 cells promoted endothelial tube formation and invasion in vitro as compared to conditioned media from SW480VEC. Using an angiogenesis array and ELISA we identified and confirmed that VEGF was upregulated in SW480FJX1 conditioned media as compared to SW480VEC. Finally SW480FJX1 cells were more tumorigenic than SW480VEC in vivo, in association with increased proliferation, vascularization, and decreased apoptosis. Taken together our results support our hypothesis that FJX1 is an important mediator of tumor biology due, in part, to its effect on tumor vascularization. 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 5150. doi:10.1158/1538-7445.AM2011-5150