Abstract 470: AR-induced miRNA124-3p.2 suppresses the metastasis-promoting factor CCL2

Abstract Objective: The standard treatment for advanced prostate cancer is androgen deprivation therapy that blocks androgen receptor (AR) signaling, but this therapy becomes ineffective within a few years, resulting in castration-resistant prostate cancer. We have previously shown that blockade of AR signaling induces CCL2 and activates cancer cells through an autocrine mechanism, but why AR blockade induces CCL2 secretion has not been elucidated. Micro RNAs (miRs) are endogenous non-coding RNAs that regulate the translation of various proteins. In this study, we investigated whether miRs are involved in CCL2 induction. Subjects and Methods: We used miRNA PCR Plate Array and Target Scan (https://www.targetscan.org) to search for miRs that are controlled by AR and bind to and repress the CCL2 gene. We knocked down the AR of human prostate cancer cell lines LNCaP and C4-2B with siRNA (siAR) and examined the expression of target miRs and CCL2. siAR-transfected LNCaP and C4-2B were transfected with target miR mimic and CCL2 expression was examined. siAR-transfected LNCaP, C4-2B, and C4-2B were transfected with target miR mimic and CCL2 expression was examined. siAR-transfected LNCaP and C4-2B were transfected with target miR mimic and CCL2 expression was examined. The target miR mimic was introduced into them, and the changes in migration ability were evaluated. Results: miR-124-3p.2 was extracted as a candidate from miRNA PCR Plate Array and Target Scan. miR-124-3p.2 expression was upregulated in both LNCaP and C4-2B when DHT was added and downregulated when CCL2 was added. In siAR LNCaP and C4-2B, the expression of CCL2 was decreased when miR-124-3p.2 mimic was introduced. Furthermore, in siAR-transfected LNCaP, C4-2B, the introduction of miR-124-3p.2 mimic suppressed the migration. Conclusion: AR suppresses CCL2 via miR124-3p.2. miR124-3p.2-mediated regulation of CCL2 may be a new therapeutic target for advanced prostate cancer. Citation Format: Shuhei Aoyama, Kouji Izumi, Atsushi Mizokami. AR-induced miRNA124-3p.2 suppresses the metastasis-promoting factor CCL2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 470.