Neuroblastoma RAS viral oncogene homolog (NRAS) G12S (NRAS G12S)

Neuroblastoma RAS viral oncogene homolog (NRAS) G12S is a specific missense mutation in the NRAS gene, where the glycine at position 12 is replaced by serine [2, 4]. This mutation occurs within the catalytic GTP-binding domain, specifically the P-loop, leading to a significant reduction in intrinsic GTPase activity and rendering the protein refractory to GTPase-activating proteins (GAPs) [1, 4]. As a result, the NRAS protein is locked in a constitutively active, GTP-bound state, providing persistent stimulatory signals to downstream pathways such as MAPK/ERK and PI3K/AKT [1, 6]. This continuous signaling drives oncogenic hallmarks, including uncontrolled cellular proliferation, enhanced survival, and resistance to apoptosis [5, 6]. NRAS G12S is a recognized driver mutation in several malignancies, most notably in melanoma, hematological cancers like acute myeloid leukemia, and colorectal cancer [4, 9, 16]. Therapeutic intervention for NRAS G12S focuses on either direct inhibition of the overactive RAS protein or blocking the downstream signaling cascade [1, 14]. While direct covalent inhibitors for G12S (similar to those for G12C) are less developed, pan-RAS inhibitors like RMC-6236 target the active "ON" state across multiple RAS variants [14]. Additionally, clinical studies have explored the use of MEK inhibitors such as binimetinib and trametinib, as well as RAF inhibitors like BGB3245, to mitigate the overactive signaling output [2, 3]. A primary therapeutic challenge is the rapid emergence of resistance through bypass pathways and the potential for toxicity when interfering with wild-type RAS functions necessary for normal tissue homeostasis [4, 16, 17].

Other names

GTPase NRasNRAS1NS6ALPS4Neuroblastoma RAS viral oncogene homolog

Direct inhibition of the active GTP-bound state (RAS-ON) by multi-selective inhibitors, allosteric inhibition of downstream signaling nodes such as MEK and RAF, and overall suppression of the hyperactive MAPK/ERK and PI3K/AKT cascades to counteract oncogenic signaling.