Abstract 269: New metabolic biomarker of ALDOA induces tumor aggressiveness in breast cancer and nicotinamide as a potential anti-tumor agent targeting ALDOA

Abstract Introduction: Nicotinamide (NAM), a water-soluble form of niacin (Vitamin B3), is a precursor of nicotinamide-adenine dinucleotide (NAD+) and regulates cellular energy metabolism. In our previous study with metabolic RNA panel assay, we confirmed ALDOA (Aldolase A) is suppressed after treatment of nicotinamide in breast cancer organoids. ALDOA is a crucial glycolytic enzyme that turns fructose-1,6-bisphosphate (FBP) into glyceraldehyde-3-phosphate. Several studies have shown that high expression of ALDOA is associated with poor prognosis in various types of cancer. However, its function in breast cancer remains unclear. Methods: ALDOA expression in breast cancer was analyzed with METABRIC data set. A total of 79 fresh cancer tissues and tumor microarrays (TMA) with 402 breast cancer patients were enrolled. Metabolic RNA sequencing panel assay was performed with human breast cancer organoids after treatment of nicotinamide. The breast cancer cell lines including MCF7, T47D, and BT474 were generated to establish stable cells in which ALDOA expression is continuously reduced using lentiviral system. Total RNA was isolated from human breast cancer cells and performed RT-PCR for Sanger sequencing. Proliferation assay was performed using cell counting kit-8. We used transwell migration and invasion assay. To identify cancer stemness, we performed sphere formation assay. Mitochondrial function was measured using the Seahorse XF24 Flux Analyzer. Results: In our previous study, after the treatment of nicotinamide, ALDOA expression in breast cancer organoids was suppressed. So we assumed that ALDOA has an oncogenic function in cellular metabolism. The expression of ALDOA was much higher in breast cancer clinical tissues compared with normal tissues. High expression of ALDOA was correlated with the worse prognosis of breast cancer patients in METABRIC public data and our own cohort. Sanger sequencing in the cell lines showed no mutation in exon5 to exon9 which is known as mutation hotspot in breast cancer. Cell proliferation activity and ability of cellular movement were inhibited in ALDOA-downregulated breast cancer cells. In the sphere formation assay, we found that the tumor cells with low expression of ALDOA decreased cancer stem cell properties. When POU2F1 or POU2F2 was suppressed, ALDOA protein expression was also inhibited. ECAR and OCR concerning mitochondrial metabolic functions were also downregulated in the tumor cells with ALDOA suppression. Conclusions: In conclusion, we suggest that ALDOA might be a key biomarker inducing tumor aggressiveness by modulating metabolic processes in breast cancer. Our results suggest that nicotinamide can be a novel therapeutic candidate targeting in breast cancer with high expression of ALDOA. Citation Format: Da Sol Kim, Cheng Hyun Lee, Soo Young Park, Han Suk Ryu. New metabolic biomarker of ALDOA induces tumor aggressiveness in breast cancer and nicotinamide as a potential anti-tumor agent targeting ALDOA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 269.