Maternal Methyl Donor Nutrients Modulate Developmental Genes in Mammary Tumors

Maternal nutrition during critical windows of development plays a pivotal role in shaping long-term disease susceptibility, including cancer risk. This study investigated whether maternal exposure to lipotropes (methyl donor nutrients) during pregnancy and lactation modulates gene expression in 7,12-dimethylbenzanthracene (DMBA)-induced mammary tumors in adult female offspring. Timed-pregnant Sprague-Dawley rats were fed with either a control or lipotrope-supplemented diet, with or without vitamin B6. Female offspring were exposed to DMBA at puberty, and mammary tumors were evaluated histologically and molecularly. DMBA-induced tumors displayed ductal carcinoma in situ-like morphology and significant upregulation of fetal mammary developmental genes (Tbx2 and Tbx3), the tumorigenesis-associated gene Tp53, and key epigenetic regulators (Hdac1, Dnmt1, and Mthfr). Estrogen receptor 1 (Esr1) mRNA expression also showed a significant increase. Maternal lipotropes supplementation significantly attenuated the expression of these genes in offspring tumors. Collectively, these findings demonstrate that maternal methyl donor nutrition modulates tumor-associated gene expression patterns, potentially by limiting the reactivation of developmental and epigenetic pathways in adulthood. This study highlights maternal nutrition as a modifiable early-life factor with important implications for long-term health programming.