Abstract PO4-28-04: Curcumin inhibits breast cancer cell proliferation by regulating ciRS-7/miR-7-5p/CKS2 axis
Authors: Abuaisha Asmaa , Kaya Murat , Suer Ilknur , Emiroglu Selman , Abanoz Fahrunnisa , Tukenmez Mustafa , Cabıoğlu Neslihan , Muslumanoglu Mahmut , Cefle Kivanc , Palanduz Sukru , Ozturk Sukru 
Published: May 2024

Background Breast cancer (BC) is the most common cancer in women worldwide. Curcumin is a polyphenolic turmeric-derived compound that has anti-proliferative and anti-tumor properties in different cancer types by acting on multiple molecules. Circular RNAs (circRNAs) are non-coding, single-stranded, covalently closed RNA molecules that act as regulators of the microRNA (miRNA) activity. Recent studies show that circRNAs are potential contributors to the onset and progression of many cancer types. CircRNA ciRS-7 acts as an oncogene and accelerates tumor progression by competitively suppressing miR-7-5p in BC. However, whether curcumin can regulate ciRS-7 to inhibit BC progression is still unclear. Method Breast Cancer cell lines (MCF-7 and T47D) and normal epithelial cell line (MCF-10A) were cultivated and treated with Curcumin (5μM, 10 μM, 20 μM) or DMSO as a control. Also, the cell lines were transfected with ciRS-7 siRNA, miR-7-5p mimic, and their non-targeted controls. The cell viability was detected by Cell Viability Detection Kit-8 (CVDK-8) using an ELISA plate reader. To detect cell migration, scratch assay was performed after 24hs of transfection and a phase contrast microscope was used to acquire images. The effect on apoptosis was detected by Annexin V-FITC Apoptosis Detection Kit using flow cytometry. Potential target genes of miR-7-5p were identified by searching for the overlapping genes in miRNet and miRTarBase v8 with the overexpressed genes in BC patient tissue samples in the TCGA database. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of ciRS-7, miR-7-5p, and the selected genes. qRT-PCR experiments were performed in duplicate and the 2−ΔΔCt method was used for relative quantitation analysis. Results Curcumin treatment, depending on the increased doses, decreased cell proliferation through inducing apoptosis in MCF-7 and T47D cancer cells. Curcumin's anti-proliferative effect was shown to be quite restricted on normal MCF-10A cells, as compared to MCF-7 and T47D cancer cells. In MCF-7 and T47D cells treated with curcumin, cell migration was dramatically inhibited. Curcumin has very little influence on the migration of MCF-10A cells. In both cancer cell group that was transfected with ciRS-7 siRNA and miR-7-5p mimic, it was observed that apoptosis was increased, proliferation was suppressed, and migration was decreased compared to its control groups. Moreover, the expression of ciRS-7 was found to be significantly decreased in the curcumin-treated group, while miR-7-5p was shown to be significantly higher. CKS2 gene one of the possible target genes of miR-7-5p that was identified by using in silico approaches, was also downregulated in curcumin-treated BC cell lines compared to its control group. ciRS-7 and CKS2 expression levels were found to be downregulated, whereas miR-7-5p expression level was found to be elevated in MCF-7 and T47D cells that were transfected with ciRS-7 siRNA. Additionally, CKS2 gene expression was found to be downregulated in miR-7-5p mimic transfected cells. Conclusion Curcumin is derived from the turmeric plant (Curcuma longa) and has been used since 3000 B.C. as a food additive. Nowadays, curcumin is one of the most essential anti-cancer substances that was examined. However, investigations on the influence of curcumin on the circRNA-miRNA-mRNA axis are scarce. Curcumin has been demonstrated to inhibit proliferation and induce apoptosis of BC cells via the ciRS-7/miR-7-5p/CKS2 axis in the present study. Keywords Breast Cancer, Curcumin, ciRS-7, miR-7-5p, CKS2

Citation Format: Asmaa Abuaisha, Murat Kaya, Ilknur Suer, Selman Emiroglu, Fahrunnisa Abanoz, Mustafa Tukenmez, Neslihan Cabıoğlu, Mahmut Muslumanoglu, Kivanc Cefle, Sukru Palanduz, Sukru Ozturk. Curcumin inhibits breast cancer cell proliferation by regulating ciRS-7/miR-7-5p/CKS2 axis [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-28-04.