Oncogene alterations in non-small cell lung cancer with <i>FGFR1</i> amplification-novel approach to stratify patients who benefit from FGFR inhibitors.
Project description:BackgroundSquamous cell lung carcinomas account for approximately 25% of new lung carcinoma cases and 40,000 deaths per year in the United States. Although there are multiple genomically targeted therapies for lung adenocarcinoma, none has yet been reported in squamous cell lung carcinoma.Methodology/principal findingsUsing SNP array analysis, we found that a region of chromosome segment 8p11-12 containing three genes-WHSC1L1, LETM2, and FGFR1-is amplified in 3% of lung adenocarcinomas and 21% of squamous cell lung carcinomas. Furthermore, we demonstrated that a non-small cell lung carcinoma cell line harboring focal amplification of FGFR1 is dependent on FGFR1 activity for cell growth, as treatment of this cell line either with FGFR1-specific shRNAs or with FGFR small molecule enzymatic inhibitors leads to cell growth inhibition.Conclusions/significanceThese studies show that FGFR1 amplification is common in squamous cell lung cancer, and that FGFR1 may represent a promising therapeutic target in non-small cell lung cancer.
Project description:Recently, FGFR1 has been found to be overexpressed in osteosarcoma and thus represents an important target for precision medicine. However, because targeted cancer therapy based on FGFR inhibitors has so far been less efficient than expected, a detailed understanding of the target is important. We have here applied proximity labelling of FGFR1 in an osteosarcoma cell line to identify determinants of FGFR1 activity. Many known FGFR interactors were identified (e.g. FRS2, PLC, RSK2, SHC4, SRC), but the data also suggested novel determinants. A strong hit in our screen was the tyrosine phosphatase PTPRG. We show that PTPRG and FGFR1 interact and colocalize at the plasma membrane where PTPRG directly dephosphorylates activated FGFR1. We further show that osteosarcoma cell lines depleted for PTPRG display increased FGFR activity and are hypersensitive to stimulation by FGF1. In addition, PTPRG depletion elevated cell growth and negatively affected the efficacy of FGFR kinase inhibitors. Thus, PTPRG may have future clinical relevance by being a predictor of outcome after FGFR inhibitor treatment.
Project description:Stem cell leukemia/lymphoma syndrome (SCLL) is driven by constitutive activation of chimeric FGFR1 kinases generated by chromosome translocations. We have shown that FGFR inhibitors significantly suppress leukemia and lymphoma development in vivo, and cell viability in vitro. Since resistance to targeted therapies is a major reason for relapse, we developed FGFR1-overexpressing mouse and human cell lines that are resistant to the specific FGFR inhibitors AZD4547 and BGJ398, as well as non-specific inhibitors, such as ponatinib, TKI258 and E3810. Two mutually exclusive mechanisms for resistance were demonstrated; an activating V561M mutation in the FGFR1 kinase domain and mutational inactivation of PTEN resulting in increased PI3K/AKT activity. Ectopic expression of PTEN in the PTEN-mutant cells resensitizes them to FGFR inhibitors. Treatment of resistant cells with BGJ398, in combination with the BEZ235 PI3K inhibitor, shows an additive effect on growth in vitro and prolongs survival in xenograft models in vivo. These studies provide the first direct evidence for both the involvement of the FGFR1 V561M mutation and PTEN inactivation in the development of resistance in leukemias overexpressing chimeric FGFR1. These studies also provide a potential strategy to treat leukemias and lymphomas driven by FGFR1 activation that become resistant to FGFR1 inhibitors.
Project description:The fibroblast growth factor receptor tyrosine kinases (FGFR1, 2, 3, and 4) represent promising therapeutic targets in a number of cancers. We have developed the first potent and selective irreversible inhibitor of FGFR1, 2, 3, and 4, which we named FIIN-1 that forms a covalent bond with cysteine 486 located in the P loop of the FGFR1 ATP binding site. We demonstrated that the inhibitor potently inhibits Tel-FGFR1-transformed Ba/F3 cells (EC(50) = 14 nM) as well as numerous FGFR-dependent cancer cell lines. A biotin-derivatized version of the inhibitor, FIIN-1-biotin, was shown to covalently label FGFR1 at Cys486. FIIN-1 is a useful probe of FGFR-dependent cellular phenomena and may provide a starting point of the development of therapeutically relevant irreversible inhibitors of wild-type and drug-resistant forms of FGFR kinases.
Project description:BACKGROUND: Recently, fibroblast growth factor receptor 1 (FGFR1) was discovered in squamous cell carcinomas (SCC) of the lung with FGFR1 amplification described as a promising predictive marker for anti-FGFR inhibitor treatment. Only few data are available regarding prevalence, prognostic significance and clinico-pathological characteristics of FGFR1-amplified and early-stage non-small cell lung carcinomas (NSCLC). We therefore investigated the FGFR1 gene status in a large number of well-characterised early-stage NSCLC. METHODS: FGFR1 gene status was evaluated using a commercially available fluorescent in situ hybridisation (FISH) probe on a tissue microarray (TMA). This TMA harbours 329 resected, formalin-fixed and paraffin-embedded, nodal-negative NSCLC with a UICC stage I-II. The FISH results were correlated with clinico-pathological features and overall survival (OS). RESULTS: The prevalence of an FGFR1 amplification was 12.5% (41/329) and was significantly (P<0.0001) higher in squamous cell carcinoma (SCC) (20.7%) than in adenocarcinoma (2.2%) and large cell carcinoma (13%). Multivariate analysis revealed significantly (P=0.0367) worse 5-year OS in patients with an FGFR1-amplified NSCLC. CONCLUSIONS: FGFR1 amplification is common in early-stage SCC of the lung and is an independent and adverse prognostic marker. Its potential role as a predictive marker for targeted therapies or adjuvant treatment needs further investigation.
Project description:Background & aimsThere is a knowledge gap in understanding mechanisms of resistance to fibroblast growth factor receptor (FGFR) inhibitors (FGFRi) and a need for novel therapeutic strategies to overcome it. We investigated mechanisms of acquired resistance to FGFRi in patients with FGFR2-fusion-positive cholangiocarcinoma (CCA).MethodsA retrospective analysis of patients who received FGFRi therapy and underwent tumor and/or cell-free DNA analysis, before and after treatment, was performed. Longitudinal circulating tumor DNA samples from a cohort of patients in the phase I trial of futibatinib (NCT02052778) were assessed. FGFR2-BICC1 fusion cell lines were developed and secondary acquired resistance mutations in the mitogen-activated protein kinase (MAPK) pathway were introduced to assess their effect on sensitivity to FGFRi in vitro.ResultsOn retrospective analysis of 17 patients with repeat sequencing following FGFRi treatment, new FGFR2 mutations were detected in 11 (64.7%) and new alterations in MAPK pathway genes in nine (52.9%) patients, with seven (41.2%) patients developing new alterations in both the FGFR2 and MAPK pathways. In serially collected plasma samples, a patient treated with an irreversible FGFRi tested positive for previously undetected BRAF V600E, NRAS Q61K, NRAS G12C, NRAS G13D and KRAS G12K mutations upon progression. Introduction of a FGFR2-BICC1 fusion into biliary tract cells in vitro sensitized the cells to FGFRi, while concomitant KRAS G12D or BRAF V600E conferred resistance. MEK inhibition was synergistic with FGFRi in vitro. In an in vivo animal model, the combination had antitumor activity in FGFR2 fusions but was not able to overcome KRAS-mediated FGFRi resistance.ConclusionsThese findings suggest convergent genomic evolution in the MAPK pathway may be a potential mechanism of acquired resistance to FGFRi.Clinical trial numberNCT02052778.Impact and implicationsWe evaluated tumors and plasma from patients who previously received inhibitors of fibroblast growth factor receptor (FGFR), an important receptor that plays a role in cancer cell growth, especially in tumors with abnormalities in this gene, such as FGFR fusions, where the FGFR gene is fused to another gene, leading to activation of cancer cell growth. We found that patients treated with FGFR inhibitors may develop mutations in other genes such as KRAS, and this can confer resistance to FGFR inhibitors. These findings have several implications for patients with FGFR2 fusion-positive tumors and provide mechanistic insight into emerging MAPK pathway alterations which may serve as a therapeutic vulnerability in the setting of acquired resistance to FGFRi.
Project description:Fibroblast growth factor receptors (FGFR) are emerging as an important therapeutic target for patients with advanced, refractory cancers. Most selective FGFR inhibitors under investigation show reversible binding, and their activity is limited by acquired drug resistance. This review summarizes the preclinical and clinical development of futibatinib, an irreversible FGFR1-4 inhibitor. Futibatinib stands out among FGFR inhibitors because of its covalent binding mechanism and low susceptibility to acquired resistance. Preclinical data indicated robust activity of futibatinib against acquired resistance mutations in the FGFR kinase domain. In early-phase studies, futibatinib showed activity in cholangiocarcinoma, and gastric, urothelial, breast, central nervous system, and head and neck cancers harboring various FGFR aberrations. Exploratory analyses indicated clinical benefit with futibatinib after prior FGFR inhibitor use. In a pivotal phase II trial, futibatinib demonstrated durable objective responses (42% objective response rate) and tolerability in previously treated patients with advanced intrahepatic cholangiocarcinoma harboring FGFR2 fusions or rearrangements. A manageable safety profile was observed across studies, and patient quality of life was maintained with futibatinib treatment in patients with cholangiocarcinoma. Hyperphosphatemia, the most common adverse event with futibatinib, was well managed and did not lead to treatment discontinuation. These data show clinically meaningful benefit with futibatinib in FGFR2-rearrangement-positive cholangiocarcinoma and provide support for further investigation of futibatinib across other indications. Future directions for this agent include elucidating mechanisms of resistance and exploration of combination therapy approaches.
Project description:Several fibroblast growth factor receptor (FGFR) inhibitors are approved or in clinical development for the treatment of FGFR-driven urothelial cancer, and molecular mechanisms of resistance leading to patient relapses have not been fully explored. We identified 21 patients with FGFR-driven urothelial cancer treated with selective FGFR inhibitors and analyzed postprogression tissue and/or circulating tumor DNA (ctDNA). We detected single mutations in the FGFR tyrosine kinase domain in seven (33%) patients (FGFR3 N540K, V553L/M, V555L/M, E587Q; FGFR2 L551F) and multiple mutations in one (5%) case (FGFR3 N540K, V555L, and L608V). Using Ba/F3 cells, we defined their spectrum of resistance/sensitivity to multiple selective FGFR inhibitors. Eleven (52%) patients harbored alterations in the PI3K-mTOR pathway (n = 4 TSC1/2, n = 4 PIK3CA, n = 1 TSC1 and PIK3CA, n = 1 NF2, n = 1 PTEN). In patient-derived models, erdafitinib was synergistic with pictilisib in the presence of PIK3CA E545K, whereas erdafitinib-gefitinib combination was able to overcome bypass resistance mediated by EGFR activation.SignificanceIn the largest study on the topic thus far, we detected a high frequency of FGFR kinase domain mutations responsible for resistance to FGFR inhibitors in urothelial cancer. Off-target resistance mechanisms involved primarily the PI3K-mTOR pathway. Our findings provide preclinical evidence sustaining combinatorial treatment strategies to overcome bypass resistance. See related commentary by Tripathi et al., p. 1964. This article is featured in Selected Articles from This Issue, p. 1949.
Project description:Achievements in cancer genetics and molecular biology have revolutionized the treatment options available for advanced melanoma. Patients with certain molecularly defined melanomas have been the most fortunate beneficiaries of recently US FDA-approved therapies that target aberrant MAPK pathway signaling, yet response rates and duration of response remain suboptimal. Furthermore, many patients harbor melanomas for which no approved targeted therapies currently exist. Since the approval of vemurafenib, a selective BRAF V600E inhibitor, in 2011, there has been a surge of preclinical and clinical studies aimed at developing novel targeted therapies for a wide range of molecularly defined melanomas. In this review, we will examine the present status and future potential of molecularly targeted therapies directed at the most significant oncogenic signaling pathways in melanoma.