The m6A methyltransferase RBM15 drives the growth of triple-negative breast cancer cells through the stimulation of serine and glycine metabolism

Abstract N 6 -adenosine methylation (m6A) is critical for controlling cancer cell growth and tumorigenesis. However, the function and detailed mechanism of how m6A methyltransferases modulate m6A levels on specific targets remains unknown. In the current study, we identified significantly elevated levels of RBM15, an m6A writer, in basal-like breast cancer (BC) patients compared to non-basal like BC and linked it to worse clinical outcome. Gene expression profiling uncovered correlations between RBM15 and serine and glycine metabolism genes including PHGDH, PSAT1, PSPH, and SHMT2. RBM15 influences overall m6A levels and, specifically, m6A of serine and glycine metabolism genes via direct binding to target RNA. Further RBM15 effects on cell growth were largely dependent on serine and glycine metabolism. Thus, RBM15 coordinates cancer cell growth through altered serine and glycine metabolism suggesting RBM15 as a new therapeutic target in BC.