Monoamine oxidase A (MAOA), a mitochondrial enzyme, catalyzes the oxidative deamination of monoamine neurotransmitters and dietary amines. It is involved in the degradation of neurotransmitters like norepinephrine, epinephrine, and serotonin, and is associated with multiple biological processes and disease-related pathways [1,2].

In prostate cancer, MAOA is upregulated in cancer cells, stromal cells, intratumoral T cells, and tumor-associated macrophages. MAOA promotes almost every stage of prostate cancer, such as castrate-resistant prostate cancer, neuroendocrine prostate cancer, metastasis, drug resistance, stemness, and perineural invasion. MAOA inhibitor treatment can reduce perineural invasion in vitro and suppress xenograft tumor growth in mice, suggesting its potential as a therapeutic target [1,4].

In gastric cancer, MAOA expression is downregulated, and it suppresses tumor growth and glycolysis, and promotes cancer cell apoptosis through the PI3K/Akt/mTOR pathway [2].

In some males with MAOA deficiency from a Dutch kindred, there was an association with abnormal behavior, including borderline mental retardation and increased impulsive behavior, although it doesn't support the "aggression gene" hypothesis due to the complexity of the relationship between genes and behavior [3].

In schizophrenia, methylation of the MAOA gene promoter was associated with the disease [5].

In conclusion, MAOA plays essential roles in the regulation of neurotransmitter levels and is involved in multiple biological processes. Studies using models, such as inhibitor-treated mice in prostate cancer research, have revealed its significance in disease development. Understanding MAOA's functions provides potential therapeutic targets for diseases like prostate and gastric cancer, and insights into the relationship between genetic factors and abnormal behaviors and mental disorders [1-5].

References:

1. Han, Hao, Li, Hui, Ma, Yifan, Zhao, Jumei, Shi, Changhong. 2023. Monoamine oxidase A (MAOA): A promising target for prostate cancer therapy. In Cancer letters, 563, 216188. doi:10.1016/j.canlet.2023.216188. https://pubmed.ncbi.nlm.nih.gov/37076041/

2. Wang, Yang-Yang, Zhou, Yao-Qi, Xie, Jia-Xuan, Zhao, En-Hao, Li, Jun. 2023. MAOA suppresses the growth of gastric cancer by interacting with NDRG1 and regulating the Warburg effect through the PI3K/AKT/mTOR pathway. In Cellular oncology (Dordrecht, Netherlands), 46, 1429-1444. doi:10.1007/s13402-023-00821-w. https://pubmed.ncbi.nlm.nih.gov/37249744/

3. Brunner, H G. . MAOA deficiency and abnormal behaviour: perspectives on an association. In Ciba Foundation symposium, 194, 155-64; discussion 164-7. doi:. https://pubmed.ncbi.nlm.nih.gov/8862875/

4. Yin, Lijuan, Li, Jingjing, Wang, Jing, Li, Qinlong, Wu, Boyang Jason. 2021. MAOA promotes prostate cancer cell perineural invasion through SEMA3C/PlexinA2/NRP1-cMET signaling. In Oncogene, 40, 1362-1374. doi:10.1038/s41388-020-01615-2. https://pubmed.ncbi.nlm.nih.gov/33420365/

5. Yang, Hao, Li, Jiajue, Ji, Aicen, Yan, Ming, Nie, Shengjie. . Methylation of the MAOA promoter is associated with schizophrenia. In Annals of translational medicine, 8, 864. doi:10.21037/atm-20-4481. https://pubmed.ncbi.nlm.nih.gov/32793708/