Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) mutant isoforms (PI3Kα (mutant))

Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha (PI3Kα) is a critical lipid kinase involved in the PI3K/AKT/mTOR signaling pathway, which regulates essential cellular processes such as growth, proliferation, and glucose metabolism [1]. Mutations in the PIK3CA gene, which encodes the p110α subunit, are highly prevalent in various human cancers, including breast, colorectal, and endometrial carcinomas [2]. These mutations typically occur at specific hotspots, such as E542K and E545K in the helical domain or H1047R in the kinase domain, resulting in constitutive activation of the enzyme and oncogenic transformation [3]. While first-generation PI3K inhibitors were limited by systemic toxicities, newer therapeutic approaches focus on isoform-specific and mutant-selective inhibition [4]. Mutant-selective inhibitors, such as RLY-2608 and STX-478, are designed to preferentially bind the altered conformation of the mutant protein, thereby sparing wild-type PI3Kα and reducing side effects like hyperglycemia [5]. Clinical development of these mutant-selective inhibitors represents a significant shift toward precision oncology, allowing for more potent suppression of tumor growth with fewer systemic toxicities [6].

Other names

PIK3CA mutantsp110α mutantsPhosphoinositide 3-kinase alpha mutantsPI3K-alpha mutants

Selective inhibition of the mutated p110α catalytic subunit of PI3K, blocking the conversion of PIP2 to PIP3 and subsequent AKT/mTOR pathway activation.