The phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (the HUGO-approved official symbol = PIK3CA; HGNC ID, HGNC:8975), also called p110α protein, is a class I PI 3-kinase catalytic subunit. The human p110α protein is encoded by the PIK3CA gene.[5]
The involvement of p110α in human cancer has been hypothesized since 1995. Support for this hypothesis came from genetic and functional studies, including the discovery of common activating PIK3CA missense mutations in common human tumors.[8] It has been found to be oncogenic and is implicated in cervical cancers.[9]PIK3CA mutations are present in over one-third of breast cancers, with enrichment in the luminal and in human epidermal growth factor receptor 2-positive subtypes (HER2 +). The three hotspot mutation positions (GLU542, GLU545, and HIS1047) have been widely reported till date.[10] While substantial preclinical data show an association with robust activation of the pathway and resistance to common therapies, clinical data do not indicate that such mutations are associated with high levels of pathway activation or with a poor prognosis. It is unknown whether the mutation predicts increased sensitivity to agents targeting the P3K pathway.[11]
Due to the association between p110α and cancer,[13] it may be an appropriate drug target. Pharmaceutical companies are designing and characterizing potential p110α isoform specific inhibitors.[14][15]
The presence of [a] PIK3CA mutation may predict response to aspirin therapy for colorectal cancer.[16][17]
PIK3CA-associated segmental overgrowth includes brain disorders such as macrocephaly-capillary malformation (MCAP) and hemimegalencephaly. It is also associated with congenital, lipomatous overgrowth of vascular malformations, epidermal nevi and skeletal/spinal anomalies (CLOVES syndrome) and fibroadipose hyperplasia (FH). The conditions are caused by heterozygous (usually somatic mosaic) mutations.[20]
Inhibition
All PI 3-kinases are inhibited by the drugs wortmannin and LY294002 but wortmannin shows better efficiency than LY294002 on the hotspot mutation positions.[21][22]
Pharmacology
In September 2017 Copanlisib, inhibiting predominantly p110α and p110δ, got FDA approval for the treatment of adult patients with relapsed follicular lymphoma (FL) who have received at least two prior systemic therapies.[23]
^Samuels Y, Waldman T (2010-01-01). "Oncogenic mutations of PIK3CA in human cancers". In Rommel C, Vanhaesebroeck B, Vogt PK (eds.). Phosphoinositide 3-kinase in Health and Disease. Current Topics in Microbiology and Immunology. Vol. 347. Springer Berlin Heidelberg. pp. 21–41. doi:10.1007/82_2010_68. ISBN9783642148156. PMC3164550. PMID20535651.
^Thirumal Kumar D, George Priya Doss C (September 2016). "Role of E542 and E545 missense mutations of PIK3CA in breast cancer: a comparative computational approach". Journal of Biomolecular Structure & Dynamics. 35 (12): 2745–2757. doi:10.1080/07391102.2016.1231082. PMID27581627.
^Fuchs CS, Ogino S (December 2013). "Aspirin therapy for colorectal cancer with PIK3CA mutation: simply complex!". Journal of Clinical Oncology. 31 (34): 4358–61. doi:10.1200/jco.2013.52.0080. PMID24166520.
^Mirzaa G, Conway R, Graham JM Jr, Dobyns WB (1993-01-01). "PIK3CA-Related Overgrowth Spectrum". In Pagon RA, Adam MP, Ardinger HH, Wallace SE, Amemiya A, Bean LJ, Bird TD, Fong CT, Mefford HC (eds.). PIK3CA-Related Segmental Overgrowth. University of Washington, Seattle. PMID23946963.
^Thirumal Kumar D, George Priya Doss C (September 2016). "Role of E542 and E545 missense mutations of PIK3CA in breast cancer: a comparative computational approach". Journal of Biomolecular Structure & Dynamics. 35 (12): 2745–2757. doi:10.1080/07391102.2016.1231082. PMID27581627.
^Kumar DT, Doss CG (2016-01-01). "Investigating the Inhibitory Effect of Wortmannin in the Hotspot Mutation at Codon 1047 of PIK3CA Kinase Domain: A Molecular Docking and Molecular Dynamics Approach". Advances in Protein Chemistry and Structural Biology. 102: 267–97. doi:10.1016/bs.apcsb.2015.09.008. PMID26827608.
^Zemlickova E, Dubois T, Kerai P, Clokie S, Cronshaw AD, Wakefield RI, Johannes FJ, Aitken A (August 2003). "Centaurin-alpha(1) associates with and is phosphorylated by isoforms of protein kinase C". Biochemical and Biophysical Research Communications. 307 (3): 459–65. doi:10.1016/s0006-291x(03)01187-2. PMID12893243.