Abstract 4380: Positive expression of estrogen receptor alpha correlates with poor prognosis and metastasis in colorectal cancer

Abstract

Abstract Background: The estrogen receptor beta (ERβ) is the predominant estrogen receptor in the normal colon mucosa, and its expression is downregulated in colorectal cancer (CRC). On the other hand, ER alpha (ERα) is very little expressed in the normal colon tissue. An increased ERα/β ratio has been shown in colon carcinomas. However, the role of ERα in CRC development and progression needs further evaluation. Aim: To investigate the role of ERα expression in CRC prognosis. Methods: A tumor tissue microarray of primary CRCs from 351 patients was stained for the expression of ERα. The nuclear staining intensity was evaluated using the Immuno-Reactive Score (IRS). Cox regression analysis and Kaplan-Meier curves were used to evaluate overall (OS) and disease-free survival (DFS). Colon cancer (CC) cells lines, SW-480, HCT-116 and HT-29 were used for in-vitro investigations. Two CC mouse models were used to investigate the expression of ERα. The zebrafish xenograft model was used to study CC cell metastasis. Untreated and ERα specific agonist (PPT, 40 nM) treated colon cancer cells were injected into the zebrafish perivitelline space. After 48 h the tale was checked for the presence of the metastasized cells. Results: ERα nuclear expression was negative in 232 and positive in 119 CRC patients, with a significantly higher expression in cancer tissue compared to normal tissue. Patients with positive ERα expression had higher TNM stage and more lymph node and distant metastasis. Positive ERα expression was independently associated with worse OS (HR=0.42; 95% CI: 0.26-0.51) and DFS (HR=0.32; 95% CI: 0.18-0.56), after adjustment for age and TNM stage. Moreover, patients with positive ERα expression had higher frequency of activated K-RAS mutation and higher expression levels of cysteinyl leukotriene receptor 1 (CysLT1R) and nuclear β-catenin, both with potent pro-tumorigenic properties. In the colon tissue from the colitis-associated colon cancer (CAC) mouse model with the Cysltr1 gene disruption, ERα expression was significantly decreased compared to wild-type (WT) mice, while in the colon of ApcMin/+ mice the ERα expression was significantly increased. In-vitro, PPT treatment significantly increased cell migration and wound closure compared to untreated cells. The zebrafish xenograft model showed that fish injected with PPT stimulated CC cells had significantly more tail metastasis compared with the control group (80% versus 67% respectively). Conclusion: Positive ERα expression correlates with poor prognosis and metastasis in colorectal cancer. Our results suggest that ERα-selective antagonists might be beneficial to combine therapeutic opportunities for improving the prognosis of CRC patients. Citation Format: Geriolda Topi, Shakti R Satapathy, Roy Roy Ehrnström, Marie-Louise Lydrup, Anita Sjölander. Positive expression of estrogen receptor alpha correlates with poor prognosis and metastasis in colorectal cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4380.