AKT1 and cancer: ,47 SP1 has been shown to have a potential role in cancer by regulating the transcription of several genes that have high GC-rich sequences in their DNA-binding promoter regions.73, 74, 75, 76 SP1 is regulated by its upstream effectors, including the phosphatidylinositol 3-kinase (PI3K)/AKT, ERK, and p38/MAPK signaling pathways.77, 78, 79, 80 Moreover, a study demonstrated that GPCRs can regulate SP1 via their downstream proteins and effectors (i.e., β-arrestin 1), which represses leukemic cell senescence.81