title: Long-term vemurafenib treatment drives inhibitor resistance through a spontaneous KRAS G12D mutation in a BRAF V600E papillary thyroid carcinoma model.
abstract: The BRAF V600E mutation is commonly observed in papillary thyroid cancer (PTC) and predominantly activates the MAPK pathway. Presence of BRAF V600E predicts increasing risk of recurrence and higher mortality rate, and treatment options for such patients are limited. Vemurafenib, a BRAF V600E inhibitor, is initially effective, but cells inevitably develop alternative mechanisms of pathway activation. Mechanisms of primary resistance have been described in short-term cultures of PTC cells; however, mechanisms of acquired resistance have not. In the present study, we investigated possible adaptive mechanisms of BRAF V600E inhibitor resistance in KTC1 thyroid cancer cells following long-term vemurafenib exposure. We found that a subpopulation of KTC1 cells acquired resistance to vemurafenib following 5 months of treatment with the inhibitor. Resistance coincided with the spontaneous acquisition of a KRAS G12D activating mutation. Increases in activated AKT, ERK1/2, and EGFR were observed in these cells. In addition, the resistant cells were less sensitive to combinations of vemurafenib and MEK1 inhibitor or AKT inhibitor. These results support the KRAS G12D mutation as a genetic mechanism of spontaneously acquired secondary BRAF inhibitor resistance in BRAF V600E thyroid cancer cells.
authors.affiliation: Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Danysh
authors.affiliation: Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Erin Y
authors.initials: EY
authors.lastname: Rieger
authors.affiliation: Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Deepankar K
authors.initials: DK
authors.lastname: Sinha
authors.affiliation: Diagnostic Genetics Program, School of Health Professions, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Caitlin V
authors.initials: CV
authors.lastname: Evers
authors.affiliation: Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Gilbert J
authors.initials: GJ
authors.lastname: Cote
authors.affiliation: Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Cabanillas
authors.affiliation: Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Hofmann
mesh_terms: D000368:Aged; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D001562:Benzimidazoles / Q000494:pharmacology; D002291:Carcinoma, Papillary / Q000188:drug therapy* / Q000235:genetics*; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D000073659:Gain of Function Mutation; D055785:Gene Knockdown Techniques; D006575:Heterocyclic Compounds, 3-Ring / Q000494:pharmacology; D006801:Humans; D007211:Indoles / Q000494:pharmacology* / Q000627:therapeutic use; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics*; D011728:Pyridones / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D034622:RNA Interference; D034741:RNA, Small Interfering; D013449:Sulfonamides / Q000494:pharmacology* / Q000627:therapeutic use; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000188:drug therapy* / Q000235:genetics*; D000077484:Vemurafenib
chemical_list: D000970:Antineoplastic Agents; D001562:Benzimidazoles; D004791:Enzyme Inhibitors; D066246:ErbB Receptors; D006575:Heterocyclic Compounds, 3-Ring; D007211:Indoles; D048369:MAP Kinase Kinase 1; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048493:Proto-Oncogene Proteins B-raf; D051057:Proto-Oncogene Proteins c-akt; D016283:Proto-Oncogene Proteins p21(ras); D011728:Pyridones; D011743:Pyrimidines; D034741:RNA, Small Interfering; D013449:Sulfonamides; D000077484:Vemurafenib; C000619637:ravoxertinib; C517975:AZD 6244; C117307:KRAS protein, human; C548887:MK 2206; C512478:EGFR protein, human; C482119:BRAF protein, human; C535150:MAPK1 protein, human; C482125:MAP2K1 protein, human
keywords: BRAF V600E; KRAS G12D; kinase inhibitor; papillary thyroid cancer (PTC); resistance