| Structural highlights
Disease
KIT_HUMAN Defects in KIT are a cause of piebald trait (PBT) [MIM:172800; also known as piebaldism. PBT is an autosomal dominant genetic developmental abnormality of pigmentation characterized by congenital patches of white skin and hair that lack melanocytes.[1] [2] [3] [4] [5] [6] [7] [8] [9] Defects in KIT are a cause of gastrointestinal stromal tumor (GIST) [MIM:606764.[10] [11] [12] [13] [14] Defects in KIT have been associated with testicular germ cell tumor (TGCT) [MIM:273300. A common solid malignancy in males. Germ cell tumors of the testis constitute 95% of all testicular neoplasms.[15] Defects in KIT are a cause of acute myelogenous leukemia (AML) [MIM:601626. AML is a malignant disease in which hematopoietic precursors are arrested in an early stage of development. Note=Somatic mutations that lead to constitutive activation of KIT are detected in AML patients. These mutations fall into two classes, the most common being in-frame internal tandem duplications of variable length in the juxtamembrane region that disrupt the normal regulation of the kinase activity. Likewise, point mutations in the kinase domain can result in a constitutively activated kinase.[16]
Function
KIT_HUMAN Tyrosine-protein kinase that acts as cell-surface receptor for the cytokine KITLG/SCF and plays an essential role in the regulation of cell survival and proliferation, hematopoiesis, stem cell maintenance, gametogenesis, mast cell development, migration and function, and in melanogenesis. In response to KITLG/SCF binding, KIT can activate several signaling pathways. Phosphorylates PIK3R1, PLCG1, SH2B2/APS and CBL. Activates the AKT1 signaling pathway by phosphorylation of PIK3R1, the regulatory subunit of phosphatidylinositol 3-kinase. Activated KIT also transmits signals via GRB2 and activation of RAS, RAF1 and the MAP kinases MAPK1/ERK2 and/or MAPK3/ERK1. Promotes activation of STAT family members STAT1, STAT3, STAT5A and STAT5B. Activation of PLCG1 leads to the production of the cellular signaling molecules diacylglycerol and inositol 1,4,5-trisphosphate. KIT signaling is modulated by protein phosphatases, and by rapid internalization and degradation of the receptor. Activated KIT promotes phosphorylation of the protein phosphatases PTPN6/SHP-1 and PTPRU, and of the transcription factors STAT1, STAT3, STAT5A and STAT5B. Promotes phosphorylation of PIK3R1, CBL, CRK (isoform Crk-II), LYN, MAPK1/ERK2 and/or MAPK3/ERK1, PLCG1, SRC and SHC1.[17] [18] [19] [20] [21] [22] [23] [24] [25] [26]
Publication Abstract from PubMed
Importance: Many cancer subtypes, including KIT-mutant gastrointestinal stromal tumors (GISTs), are driven by activating mutations in tyrosine kinases and may initially respond to kinase inhibitors but frequently relapse owing to outgrowth of heterogeneous subclones with resistance mutations. KIT inhibitors commonly used to treat GIST (eg, imatinib and sunitinib) are inactive-state (type II) inhibitors. Objective: To assess whether combining a type II KIT inhibitor with a conformation-complementary, active-state (type I) KIT inhibitor is associated with broad mutation coverage and global disease control. Design, Setting, and Participants: A highly selective type I inhibitor of KIT, PLX9486, was tested in a 2-part phase 1b/2a trial. Part 1 (dose escalation) evaluated PLX9486 monotherapy in patients with solid tumors. Part 2e (extension) evaluated PLX9486-sunitinib combination in patients with GIST. Patients were enrolled from March 2015 through February 2019; data analysis was performed from May 2020 through July 2020. Interventions: Participants received 250, 350, 500, and 1000 mg of PLX9486 alone (part 1) or 500 and 1000 mg of PLX9486 together with 25 or 37.5 mg of sunitinib (part 2e) continuously in 28-day dosing cycles until disease progression, treatment discontinuation, or withdrawal. Main Outcomes and Measures: Pharmacokinetics, safety, and tumor responses were assessed. Clinical efficacy end points (progression-free survival and clinical benefit rate) were supplemented with longitudinal monitoring of KIT mutations in circulating tumor DNA. Results: A total of 39 PLX9486-naive patients (median age, 57 years [range, 39-79 years]; 22 men [56.4%]; 35 [89.7%] with refractory GIST) were enrolled in the dose escalation and extension parts. The recommended phase 2 dose of PLX9486 was 1000 mg daily. At this dose, PLX9486 could be safely combined with 25 or 37.5 mg daily of sunitinib continuously. Patients with GIST who received PLX9486 at a dose of 500 mg or less, at the recommended phase 2 dose, and with sunitinib had median (95% CI) progression-free survivals of 1.74 (1.54-1.84), 5.75 (0.99-11.0), and 12.1 (1.34-NA) months and clinical benefit rates (95% CI) of 14% (0%-58%), 50% (21%-79%), and 80% (52%-96%), respectively. Conclusions and Relevance: In this phase 1b/2a nonrandomized clinical trial, type I and type II KIT inhibitors PLX9486 and sunitinib were safely coadministered at the recommended dose of both single agents in patients with refractory GIST. Results suggest that cotargeting 2 complementary conformational states of the same kinase was associated with clinical benefit with an acceptable safety profile. Trial Registration: ClinicalTrials.gov Identifier: NCT02401815.
Association of Combination of Conformation-Specific KIT Inhibitors With Clinical Benefit in Patients With Refractory Gastrointestinal Stromal Tumors: A Phase 1b/2a Nonrandomized Clinical Trial.,Wagner AJ, Severson PL, Shields AF, Patnaik A, Chugh R, Tinoco G, Wu G, Nespi M, Lin J, Zhang Y, Ewing T, Habets G, Burton EA, Matusow B, Tsai J, Tsang G, Shellooe R, Carias H, Chan K, Rezaei H, Sanftner L, Marimuthu A, Spevak W, Ibrahim PN, Inokuchi K, Alcantar O, Michelson G, Tsiatis AC, Zhang C, Bollag G, Trent JC, Tap WD JAMA Oncol. 2021 Jul 8. pii: 2781610. doi: 10.1001/jamaoncol.2021.2086. PMID:34236401[27]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Fleischman RA. Human piebald trait resulting from a dominant negative mutant allele of the c-kit membrane receptor gene. J Clin Invest. 1992 Jun;89(6):1713-7. PMID:1376329 doi:http://dx.doi.org/10.1172/JCI115772
- ↑ Spritz RA, Giebel LB, Holmes SA. Dominant negative and loss of function mutations of the c-kit (mast/stem cell growth factor receptor) proto-oncogene in human piebaldism. Am J Hum Genet. 1992 Feb;50(2):261-9. PMID:1370874
- ↑ Giebel LB, Spritz RA. Mutation of the KIT (mast/stem cell growth factor receptor) protooncogene in human piebaldism. Proc Natl Acad Sci U S A. 1991 Oct 1;88(19):8696-9. PMID:1717985
- ↑ Spritz RA, Holmes SA, Itin P, Kuster W. Novel mutations of the KIT (mast/stem cell growth factor receptor) proto-oncogene in human piebaldism. J Invest Dermatol. 1993 Jul;101(1):22-5. PMID:7687267
- ↑ Riva P, Milani N, Gandolfi P, Larizza L. A 12-bp deletion (7818del12) in the c-kit protooncogene in a large Italian kindred with piebaldism. Hum Mutat. 1995;6(4):343-5. PMID:8680409 doi:10.1002/humu.1380060409
- ↑ Pignon JM, Giraudier S, Duquesnoy P, Jouault H, Imbert M, Vainchenker W, Vernant JP, Tulliez M. A new c-kit mutation in a case of aggressive mast cell disease. Br J Haematol. 1997 Feb;96(2):374-6. PMID:9029028
- ↑ Spritz RA, Beighton P. Piebaldism with deafness: molecular evidence for an expanded syndrome. Am J Med Genet. 1998 Jan 6;75(1):101-3. PMID:9450866
- ↑ Nomura K, Hatayama I, Narita T, Kaneko T, Shiraishi M. A novel KIT gene missense mutation in a Japanese family with piebaldism. J Invest Dermatol. 1998 Aug;111(2):337-8. PMID:9699740 doi:10.1046/j.1523-1747.1998.00269.x
- ↑ Syrris P, Malik NM, Murday VA, Patton MA, Carter ND, Hughes HE, Metcalfe K. Three novel mutations of the proto-oncogene KIT cause human piebaldism. Am J Med Genet. 2000 Nov 6;95(1):79-81. PMID:11074500
- ↑ Pignon JM, Giraudier S, Duquesnoy P, Jouault H, Imbert M, Vainchenker W, Vernant JP, Tulliez M. A new c-kit mutation in a case of aggressive mast cell disease. Br J Haematol. 1997 Feb;96(2):374-6. PMID:9029028
- ↑ Nishida T, Hirota S, Taniguchi M, Hashimoto K, Isozaki K, Nakamura H, Kanakura Y, Tanaka T, Takabayashi A, Matsuda H, Kitamura Y. Familial gastrointestinal stromal tumours with germline mutation of the KIT gene. Nat Genet. 1998 Aug;19(4):323-4. PMID:9697690 doi:10.1038/1209
- ↑ Hirota S, Isozaki K, Moriyama Y, Hashimoto K, Nishida T, Ishiguro S, Kawano K, Hanada M, Kurata A, Takeda M, Muhammad Tunio G, Matsuzawa Y, Kanakura Y, Shinomura Y, Kitamura Y. Gain-of-function mutations of c-kit in human gastrointestinal stromal tumors. Science. 1998 Jan 23;279(5350):577-80. PMID:9438854
- ↑ Beghini A, Tibiletti MG, Roversi G, Chiaravalli AM, Serio G, Capella C, Larizza L. Germline mutation in the juxtamembrane domain of the kit gene in a family with gastrointestinal stromal tumors and urticaria pigmentosa. Cancer. 2001 Aug 1;92(3):657-62. PMID:11505412
- ↑ Chen LL, Sabripour M, Wu EF, Prieto VG, Fuller GN, Frazier ML. A mutation-created novel intra-exonic pre-mRNA splice site causes constitutive activation of KIT in human gastrointestinal stromal tumors. Oncogene. 2005 Jun 16;24(26):4271-80. PMID:15824741 doi:1208587
- ↑ Pignon JM, Giraudier S, Duquesnoy P, Jouault H, Imbert M, Vainchenker W, Vernant JP, Tulliez M. A new c-kit mutation in a case of aggressive mast cell disease. Br J Haematol. 1997 Feb;96(2):374-6. PMID:9029028
- ↑ Pignon JM, Giraudier S, Duquesnoy P, Jouault H, Imbert M, Vainchenker W, Vernant JP, Tulliez M. A new c-kit mutation in a case of aggressive mast cell disease. Br J Haematol. 1997 Feb;96(2):374-6. PMID:9029028
- ↑ Blume-Jensen P, Ronnstrand L, Gout I, Waterfield MD, Heldin CH. Modulation of Kit/stem cell factor receptor-induced signaling by protein kinase C. J Biol Chem. 1994 Aug 26;269(34):21793-802. PMID:7520444
- ↑ Kozlowski M, Larose L, Lee F, Le DM, Rottapel R, Siminovitch KA. SHP-1 binds and negatively modulates the c-Kit receptor by interaction with tyrosine 569 in the c-Kit juxtamembrane domain. Mol Cell Biol. 1998 Apr;18(4):2089-99. PMID:9528781
- ↑ Taniguchi Y, London R, Schinkmann K, Jiang S, Avraham H. The receptor protein tyrosine phosphatase, PTP-RO, is upregulated during megakaryocyte differentiation and Is associated with the c-Kit receptor. Blood. 1999 Jul 15;94(2):539-49. PMID:10397721
- ↑ Wollberg P, Lennartsson J, Gottfridsson E, Yoshimura A, Ronnstrand L. The adapter protein APS associates with the multifunctional docking sites Tyr-568 and Tyr-936 in c-Kit. Biochem J. 2003 Mar 15;370(Pt 3):1033-8. PMID:12444928 doi:10.1042/BJ20020716
- ↑ Lennartsson J, Wernstedt C, Engstrom U, Hellman U, Ronnstrand L. Identification of Tyr900 in the kinase domain of c-Kit as a Src-dependent phosphorylation site mediating interaction with c-Crk. Exp Cell Res. 2003 Aug 1;288(1):110-8. PMID:12878163
- ↑ Voytyuk O, Lennartsson J, Mogi A, Caruana G, Courtneidge S, Ashman LK, Ronnstrand L. Src family kinases are involved in the differential signaling from two splice forms of c-Kit. J Biol Chem. 2003 Mar 14;278(11):9159-66. Epub 2003 Jan 2. PMID:12511554 doi:10.1074/jbc.M211726200
- ↑ Sun J, Pedersen M, Bengtsson S, Ronnstrand L. Grb2 mediates negative regulation of stem cell factor receptor/c-Kit signaling by recruitment of Cbl. Exp Cell Res. 2007 Nov 1;313(18):3935-42. Epub 2007 Sep 4. PMID:17904548 doi:10.1016/j.yexcr.2007.08.021
- ↑ Sun J, Pedersen M, Ronnstrand L. The D816V mutation of c-Kit circumvents a requirement for Src family kinases in c-Kit signal transduction. J Biol Chem. 2009 Apr 24;284(17):11039-47. doi: 10.1074/jbc.M808058200. Epub 2009, Mar 5. PMID:19265199 doi:10.1074/jbc.M808058200
- ↑ Kim SY, Kang JJ, Lee HH, Kang JJ, Kim B, Kim CG, Park TK, Kang H. Mechanism of activation of human c-KIT kinase by internal tandem duplications of the juxtamembrane domain and point mutations at aspartic acid 816. Biochem Biophys Res Commun. 2011 Jul 1;410(2):224-8. doi:, 10.1016/j.bbrc.2011.05.111. Epub 2011 May 27. PMID:21640708 doi:10.1016/j.bbrc.2011.05.111
- ↑ Chaix A, Lopez S, Voisset E, Gros L, Dubreuil P, De Sepulveda P. Mechanisms of STAT protein activation by oncogenic KIT mutants in neoplastic mast cells. J Biol Chem. 2011 Feb 25;286(8):5956-66. doi: 10.1074/jbc.M110.182642. Epub 2010 , Dec 6. PMID:21135090 doi:10.1074/jbc.M110.182642
- ↑ Wagner AJ, Severson PL, Shields AF, Patnaik A, Chugh R, Tinoco G, Wu G, Nespi M, Lin J, Zhang Y, Ewing T, Habets G, Burton EA, Matusow B, Tsai J, Tsang G, Shellooe R, Carias H, Chan K, Rezaei H, Sanftner L, Marimuthu A, Spevak W, Ibrahim PN, Inokuchi K, Alcantar O, Michelson G, Tsiatis AC, Zhang C, Bollag G, Trent JC, Tap WD. Association of Combination of Conformation-Specific KIT Inhibitors With Clinical Benefit in Patients With Refractory Gastrointestinal Stromal Tumors: A Phase 1b/2a Nonrandomized Clinical Trial. JAMA Oncol. 2021 Jul 8. pii: 2781610. doi: 10.1001/jamaoncol.2021.2086. PMID:34236401 doi:http://dx.doi.org/10.1001/jamaoncol.2021.2086
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