Abstract 1710: Role of Nurr1 in cervical cancer pathogenic pathway

Aims: To study the oncogenic role of Nurr1 in cervical cancer and elucidate the underlying mechanism. Background: Orphan nuclear receptor related-1 protein (Nurr1) belonging to the NR4A family is important for carcinogenesis in multiple biological processes such as cell proliferation and apoptosis. It has been reported that the expression of Nurr1 is significantly correlated with various types of cancer, such as prostate and breast cancer. However, the significance of Nurr1 in cervical cancer etiology remains poorly understood. Methods: Primary cancer cells were established from tumor tissues resected from cervical cancer patients. Six pairs of attached and spheroid cells derived from primary cervical cancer tissues were established namely CP-1A/CP-1S, CP-2A/CP-2S, CP-3A/CP-3S, CP-4A/CP-4S, CP-5A/CP-5S and CP-6A/CP-6S. A microarray was performed to identify differentially expressed genes in two pairs of attached and sphere cells, followed by validation with qPCR. Stable clones of cervical cancer cell lines with Nurr1 overexpression and knock-down were generated. The role of the selected gene was then functionally characterized by XTT assay, migration assay, spheroid formation assay, apoptosis assay, in vitro and in vivo tumorigenicity assay in cervical cancer cell lines. Downstream proteins of Nurr1 were detected by western blot. Results: Microarray analysis showed that Nurr1 was highly expressed in sphere cells as compared with attached cells. Relative expression of Nurr1 mRNA in sphere cells was approximately 200-fold more than that in attached cells in qPCR validation. Cancer cell lines, in which Nurr1 was transiently knocked down by siRNA demonstrated an attenuation in proliferation rate, migration, spheroid formation and colony formation. By flow cytometric analysis, more cells were detected in early apoptotic stage with Nurr1 siRNA transfection as compared with NTC siRNA transfected cells, suggesting the role of Nurr1 in preventing cervical cancer cells from apoptosis. Western blotting also demonstrated that there was an increased expression of Bim and p21 in Nurr1 silenced cells. This may indicate the involvement of Nurr1 in modulating the transcription of pro-apoptotic and tumor suppressor genes. Conclusion: Nurr1 is a potential oncogenic target in cervical cancer pathogenic pathway. Suppression of Nurr1 expression attenuated cancer progression and promoted apoptosis. Citation Format: Kok Ting Wan, Thomas Ho Yin Leung, Michelle Kwan Yee Siu, Hextan Yuen Sheung Ngan. Role of Nurr1 in cervical cancer pathogenic pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1710.