Abstract 1849: CXXC5 is overexpressed in human prostate epithelial cancer cell lines in culture and human prostate cancer tissue
Authors: Benedetti Ines , Bettin Alfonso , Reyes Niradiz 
Published: July 2016

Abstract
Background: CXXC5 encodes a retinoid-inducible nuclear factor that plays an essential role in human hematopoiesis (1, 2). We have previously identified the differential expression of this gene in rat cancer cell lines with different cancer phenotypes (3). However, knowledge on the expression of this gene in human prostate cell lines or tissue is lacking, both at the transcript and protein level.
Methods: Prospective study conducted between January-2012 through June-2015 at the University of Cartagena, Colombia. Expression of CXXC5 was evaluated by quantitative PCR, both in prostate cancer cell lines and tissue biopsies from patients undergoing transrectal ultrasound-guided prostate needle biopsy for suspected prostate cancer (PCa). A total of 65 prostate tissue samples, consisting of 24 benign prostatic tissue biopsies and 41 prostate cancer tissue biopsies were included in the study. Transcript levels in individual biopsies from each group were normalized to transcript levels of beta-actin of the corresponding sample and compared. The protein expression level of CXXC5 was analyzed by immunohistochemistry in benign and malignant prostate tissue. A final score was determined by multiplying the highest intensity of staining by the mean percentage of positive cells stained to yield a value between 0 and 300 for each case. For statistical analysis we compared parameters between group of cases with PCa and without PCa. This study was approved by the Ethical Review Board of the academic institution.
Results: CXXC5 transcript expression levels were significantly lower in immortalized non-tumoral prostate cell line PWR-1E compared to PCa cell lines: LNCaP (Fold change: 10.5, p = 0.001), and PC3 (Fold change: 2.8, p = 0.014). In prostate tissue we observed a significant higher expression in low grade prostate cancer compared to benign prostate tissue (p = 0.034). IHC evaluation showed that CXXC5 staining was higher in tissue samples from patients with prostate cancer compared to patients with benign disease (p = &lt;0.001). In the prostate cancer group, immunostaining was also stronger in malignant acini than in adjacent, benign acini, within the same patient sample.
Conclusions: CXXC5 exhibits differential expression in prostate cell lines with different cancer phenotypes and between cancer and benign prostate tissue. Additional studies are required to determine the biological and clinical significance of CXXC5 in prostate cancer.
References
1. J Biol Chem, 2009. 284(6): p. 3672-81.
2. Oncotarget, 2013. 4(9): p. 1438-48.
3. Biomedica, 2007. 27(2): p. 190-203.
Citation Format: Ines Benedetti, Alfonso Bettin, Niradiz Reyes. CXXC5 is overexpressed in human prostate epithelial cancer cell lines in culture and human prostate cancer tissue. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1849.