👤 Danielle Peifer

Fibroblast growth factor receptor 1 (FGFR1) is recurrently mutated at p.N546 in neuroblastoma. We examined whether mutant FGFR1 is an oncogenic driver, a predictive biomarker, and an actionable vulnerability in this malignancy. FGFR1 mutations at p.N546 were associated with high-risk disease and rapid tumor progression, resulting in dismal outcome for these patients. Ectopic expression of FGFR1N546K induced constitutive downstream signaling and IL-3-independent growth in Ba/F3 cells, indicating oncogene-addicted proliferation. In FGFR1N546K;MYCN transgenic mice, neuroblastoma developed within the first days of life, with fatal outcome within 3 weeks, reflecting the devastating clinical phenotypes of patients with FGFR1-mutant, high-risk neuroblastoma. Treatment with FGFR inhibitors impaired proliferation and pathway activation in FGFR1N546K-expressing Ba/F3 and patient-derived FGFR1N546K-mutant neuroblastoma cells and inhibited tumor growth in FGFR1N546K;MYCN transgenic mice and in a chemotherapy-resistant, patient-derived xenograft mouse model. In addition, partial regression of FGFR1N546K-mutant tumor lesions occurred upon treatment with the FGFR inhibitor futibatinib and low-intensity chemotherapy in a patient with refractory neuroblastoma. Together, our data demonstrate that FGFR1N546K is a strong oncogenic driver in neuroblastoma associated with failure of current standard chemotherapy and suggest potential clinical benefit of FGFR-directed therapies in patients with high-risk mutant FGFR1. Show less

Batten disease is a rare, progressive neurogenetic disorder composed of 13 genotypes that often presents in childhood. Children present with seizures, vision loss, and developmental regression. Neurorehabilitation services (i.e., physical therapy, occupational therapy, and speech-language therapy) can help improve the quality of life for children and their families. Owing to the rarity of Batten disease, there are no standardized clinical recommendations or outcome assessments. To describe developmental profiles, current dose of neurorehabilitation, and outcome assessments used clinically for children diagnosed with Batten disease. Electronic medical records of 70 children with Batten disease (subtypes n = 5 CLN1; n = 25 CLN2; n = 23 CLN3; n = 17 CLN6) were reviewed (7.0 ± 3.4 years). Descriptive statistics were used to describe clinical features, developmental skills, dose of neurorehabilitation, and outcome assessment use. Across CLN subtypes, most children experienced vision impairments (61%) and seizures (68%). Most children demonstrated delays in fine motor (65%), gross motor (80%), cognitive (63%), and language skills (83%). The most common frequency of neurorehabilitation was weekly (42% to 43%). Two standardized outcome assessments were used to track developmental outcomes: Peabody Developmental Motor Scales, second edition (30% of children completed this assessment) and Preschool Language Scales, fifth edition (27.4% of children completed this assessment). Neurorehabilitation professionals should understand the clinical features and prognosis for children with Batten disease. The child's clinical features and family preferences should guide the rehabilitation plan of care. Future work needs to be completed to define dosing parameters and validate outcome assessments for neurorehabilitation services. Show less

The discovery of frequent 8p11-p12 amplifications in squamous cell lung cancer (SQLC) has fueled hopes that FGFR1, located inside this amplicon, might be a therapeutic target. In a clinical trial, only 11% of patients with 8p11 amplification (detected by FISH) responded to FGFR kinase inhibitor treatment. To understand the mechanism of FGFR1 dependency, we performed deep genomic characterization of 52 SQLCs with 8p11-p12 amplification, including 10 tumors obtained from patients who had been treated with FGFR inhibitors. We discovered somatically altered variants of FGFR1 with deletion of exons 1-8 that resulted from intragenic tail-to-tail rearrangements. These ectodomain-deficient FGFR1 variants (ΔEC-FGFR1) were expressed in the affected tumors and were tumorigenic in both in vitro and in vivo models of lung cancer. Mechanistically, breakage-fusion-bridges were the source of 8p11-p12 amplification, resulting from frequent head-to-head and tail-to-tail rearrangements. Generally, tail-to-tail rearrangements within or in close proximity upstream of FGFR1 were associated with FGFR1 dependency. Thus, the genomic events shaping the architecture of the 8p11-p12 amplicon provide a mechanistic explanation for the emergence of FGFR1-driven SQLC. Specifically, we believe that FGFR1 ectodomain-deficient and FGFR1-centered amplifications caused by tail-to-tail rearrangements are a novel somatic genomic event that might be predictive of therapeutically relevant FGFR1 dependency. Show less

Testosterone depletion is a common aim in the treatment of hormone-dependent prostate cancer, since the steroid boosts the tumor's proliferation. Therefore, inhibition of 17β-hydroxysteroid dehydrogenase type 3 (17βHSD3), which catalyzes the carbonyl reduction of androstenedione to testosterone, represents an expedient therapeutic drug target. Among the compounds targeting 17βHSD3, tetrahydrodibenzazocines have been reported to be highly potent inhibitors. Thus, we hypothesized that structural analogs to the tetrahydrodibenzazocine scaffold, namely diazocines, which contain an azo group instead of the ethylene moiety, are also able to inhibit 17βHSD3. Diazocines consist of a photoresponsive core and can be isomerized from Z into E configuration by irradiation with a specific wavelength. In the present study, 17βHSD3 inhibition by diazocine photoisomers was examined in transfected human embryonic kidney 293 cells (HEK-293) and isolated microsomes. For this purpose, cells or microsomes were treated with androstenedione and incubated for 2 or 24 h in the presence or absence of irradiated and non-irradiated diazocines. Testosterone formation was determined by uHPLC. We report a weak inhibition of 17βHSD3 activity by diazocines in HEK-293 cells and microsomes. Furthermore, we found no significant difference between samples treated with irradiated and non-irradiated diazocines in terms of inhibition. However, we detected a new compound by HPLC analysis, which only appeared in light-treated samples, indicating a chemical modification of the photoswitched diazocines, presumably rendering them ineffective. Further investigations revealed that this modification occurs in the presence of reducing agents like dithiothreitol and glutathione. A preliminary mass-spectrometric analysis suggests that the N-N double bond is reduced, resulting in a dianiline derivative. Nevertheless, optimized photoswitchable diazocine derivatives, which are stable in a cellular environment, might serve as potent 17βHSD3 inhibitors, effective only in irradiated tissue. Show less