Abstract 2787: Effect of miR-494 modulation in colorectal cancer (CRC): Clinical outcome, target expression and cell characteristics

Background. MicroRNAs are small, single-stranded non-coding RNA molecules that play major role in gene regulation. miRNAs have been reported as both tumor suppressive and oncogenic and are promising candidates for cancer prognosis and treatment. miR-494 is known to promote cell migration and invasion in CRC. Our study aimed to further explore the role of miR-494 modulation (inhibition and overexpression) in CRC. Methods. We evaluated the impact of tumor gene expression of MIR494 on outcomes (overall survival: OS; progression-free survival: PFS) in data for 433 metastatic CRC (mCRC) patients (pts) (bevacizumab [bev] (N = 226) vs cetuximab [cet] (N = 207)) enrolled in randomized phase III CALGB/SWOG 80405 trial obtained from Alliance for Clinical Trials in Oncology. RNA extracted from FFPE tumor samples was sequenced using the HiSeq 2500 (Illumina). Gene expression was divided into high, medium and low. Associations were assessed by log-rank test and multivariable Cox proportional hazards regression model. Treatment-gene interactions were analyzed using the likelihood ratio test. CRC cell lines HCT116 and HT29 were transfected with miR-494 inhibitors and mimics for 48 hours and total RNA was collected, followed by RT-qPCR (miR-494 and target genes BMAL1, PAK1, CDH1, CDH2, SNAI1, TWIST) and clonogenic assays. Results. High miR-494 was significantly associated with worse PFS in overall (median survival: high vs low: 9.3 vs 11.3 months, P<0.025) and cet-treated (median survival high vs low: 9.2 vs 9.6 months, P<0.025) mCRC cohorts, while no significance was observed in bev-treated mCRC. Multivariable Cox model showed significant association between high miR-494 and worse PFS and OS in the cet-treated cohort; however, treatment-gene interaction was not statistically significant. Expression analysis revealed miR-494 was significantly reduced and increased following inhibitor and mimic transfection, respectively. Differential gene expression of the target genes analyzed was observed between the miR-494 inhibitor and mimic-treated HCT116 and HT29 samples. In HCT116 cells, inhibition of miR-494 significantly (P < 0.01) reduced expression of PAK1, while increased the expression of CDH1. The number of colonies formed relatively increased after transfection with miR-494 inhibitor compared to miR-494 mimic. Conclusion. Our findings showed that high miR-494 expression correlated with worse PFS overall and in cet-treated mCRC pts. It would be interesting to check for potential associations with EGFR signaling (direct or indirect). Further studies are warranted for efficient targeting and to gain better understanding of the associated signaling involved in miR-494 modulation in CRC. Support: U10CA180821, U10CA180882; U10CA180888 (SWOG): Genentech. https://acknowledgments.alliancefound.org; P30CA014089, UG1CA180830 [HJL]. Clinicaltrials.gov Identifier: NCT00265850 Citation Format: Pooja Mittal, Joshua Millstein, Shivani Soni, Francesca Battaglin, Karam Ashouri, Sandra Algaze, Priya Jayachandran, Yan Yang, Lesly T. Gonzalez, Unnati H. Shah, Wu Zhang, Fang-Shu Ou, Alan P. Venook, Indrakant K. Singh, Heinz J. Lenz. Effect of miR-494 modulation in colorectal cancer (CRC): Clinical outcome, target expression and cell characteristics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2787.