Insulin-like Growth Factor-1 Receptor Inhibitor Research Articles

Transcriptomic profiling of thyroid eye disease orbital fat demonstrates differences in adipogenicity and IGF-1R pathway.

Despite recent advances in the treatment of thyroid eye disease thyroid-related eye disease (TED), marked gaps remain in our understanding of the underlying molecular mechanisms, particularly concerning the insulin-like growth factor-1 receptor (IGF-1R) pathway. To dissect the pathophysiology of TED, we used single-nucleus RNA-Seq to analyze orbital fat specimens from both patients with TED and matched individuals acting as controls. The analysis demonstrated a marked increase in the proportion of fibroblasts transitioning to adipogenesis in the orbital fat of patients with TED compared with that in control patients. This was associated with diverse alterations in immune cell composition. Significant alterations in the IGF-1R signaling pathway were noted between TED specimens and those from control patients, indicating a potential pathological mechanism driven by IGF-1R signaling abnormalities. Additionally, our data showed that linsitinib, a small-molecule inhibitor of IGF-1R, effectively reduced adipogenesis in TED orbital fibroblasts in vitro, suggesting its potential utility as a therapeutic agent. Our findings reveal that, beyond immune dysfunction, abnormal IGF-1R signaling leading to enhanced adipogenesis is a crucial pathogenic mechanism in TED.

Linsitinib inhibits IGF-1-induced cell proliferation and hyaluronic acid secretion by suppressing PI3K/Akt and ERK pathway in orbital fibroblasts from patients with thyroid-associated ophthalmopathy.

Thyroid-associated ophthalmopathy (TAO), an autoimmune disorder of the retrobulbar tissue, is present in up to 50 percent of Graves's hyperthyroidism patients. Insulin-like growth factor 1 receptor (IGF-1R) has received attention as a target for the development of therapeutic agent for TAO. IGF-1R and TSHR (thyroid stimulating hormone receptor) interact with each other to form a physical or functional complex, further promoting the development of TAO. Linsitinib, OSI-906, is an inhibitor of IGF-1R and has been reported to inhibit cell proliferation of several tumor cells. Linsitinib has been receiving attention not only for its anticancer effect, but also for its anti-inflammatory effects. It has been reported that linsitinib reduces infiltration of inflammatory cells in orbital tissues, resulting in the reduction of muscle edema and adipose tissues in an experimental murine model for Graves' disease. In the current study, we investigated the issue of whether linsitinib inhibits the IGF-1-induced proliferation of orbital fibroblasts (OFs) via the suppression of phosphatidylinositol 3-kinase (PI3K) / Akt and extracellular signal-regulated kinase (ERK) pathway. Our results showed that pretreatment with linsitinib inhibited IGF-1-induced cell proliferation and hyaluronic acid secretion in the OFs of TAO patients. In addition, our results showed that pretreatment with linsitinib inhibited IGF-1-induced phosphorylation of IGF-1Rβ at Tyr1135, Akt at Ser473, and ERK in the OFs of patients with TAO. These results indicate that linsitinib inhibits IGF-1-induced cell proliferation and hyaluronic acid secretion in the OFs of TAO patients by suppressing the PI3K/Akt and ERK pathways, validating the use of linsitinib as a novel therapeutic agent for TAO.

Crosstalk between prolactin, insulin-like growth factors, and thyroid hormones in feather growth regulation in neonatal chick wings.

The elongation of primary feathers in neonatal chicks is delayed by the late-feathering K gene located on the Z chromosome. We recently found that the K gene slows feather growth by reducing the number of functional prolactin (PRL) receptor (PRLR) dimers. In this study, we investigated the molecular mechanisms by which PRL promotes feather elongation. RT-qPCR and immunohistochemistry analyses revealed that PRLRs are predominantly localized in the pulp rather than in the epidermal layer of the feather follicle. Treatment of primary cultured feather pulp cells with PRL increased the expression of mRNAs for insulin-like growth factors (IGFs; IGF-1 and IGF-2) and type 2 deiodinase (DIO2). Furthermore, treatments with IGF-1 and triiodothyronine (T3) reciprocally enhanced the expression of mRNAs for DIO2 and IGFs. Additionally, BrdU staining in neonatal chicks showed that T3 promoted cell proliferation in both the epidermal layer and pulp cells, while this effect was suppressed by an IGF-1 receptor (IGF1R) inhibitor. These findings suggest a novel model in which PRL upregulates IGFs and DIO2 in feather pulp cells, creating a positive feedback loop between IGFs and T3, ultimately leading to the promotion of cell proliferation in both the epidermal layer and the pulp cells by IGFs. This is the first report proposing crosstalk between PRL, thyroid hormone (TH), and IGFs in feather follicles.

DDDR-37. OHSV AND RADIATION THERAPIES SENSITIZE GLIOBLASTOMA TO IGF1R-TARGETED THERAPY AND SYNERGIZE IN TRIPLE COMBINATION THERAPY

Abstract Glioblastoma (GBM) continues to have a dismal prognosis despite remarkable advances in the field due to both tumor-intrinsic factors (i.e., IDH1 or EGFRvIII mutations) and extrinsic factors (i.e., relating to the tumor microenvironment (TME)), necessitating therapeutic innovation. Oncolytic herpes simplex virus-1 (oHSV) is an FDA-approved therapy that has shown promising results in clinical trials; however, therapeutic efficacy is limited to a small subset of patients. Thus, elucidating both the tumor-TME interplay and feedback/feedforward tumor-cell signaling in the context of viro-immunotherapy is essential in augmenting therapeutic outcomes. We recently discovered a novel mechanism of resistance to oHSVs, in which infection increases secretion of Insulin-like growth factor 2 (IGF2), activating the Insulin-like Growth Factor-1 Receptor (IGF1R). Upregulation of the IGF1R signaling pathway in GBM is correlated with poor prognosis and has been implicated in resistance to conventional therapies including radiotherapy (RTx). Herein, we further elucidate the impact of oHSVs on IGF1R activation, demonstrating a dose-dependent enhancement of downstream signaling. While IGF1R targeting therapies (e.g., OSI-966, Picropodophyllin (PPP)) have displayed limited efficacy in clinical trials, they significantly increased oHSV-induced cytotoxicity in all tested primary GBM cells compared to either agent alone in vitro and in vivo, resulting in a dose-dependent increase in PARP and caspase 3 activity by western blot and immunohistochemistry. We further found that RTx-induced IGF1 secretion and subsequent IGF1R activation were enhanced when combined with oHSV treatment. Triple combination therapy with oHSV, IGF1R inhibition, and RTx significantly increased tumor cell killing in vitro and improved survival of orthotopic GBM tumor-bearing mice. Collectively, our study provides preclinical evidence of enhanced therapeutic efficacy of oHSVs and RTx in combination with IGF1R blockade, supporting future use of IGF1R inhibitors in combination with the standard of care and FDA-approved oHSV therapies in patients with GBM.

Metformin Impairs Linsitinib Anti-Tumor Effect on Ovarian Cancer Cell Lines.

Ovarian cancer (OC) remains one of the leading causes of cancer-related mortality among women. Targeting the insulin-like growth factor 1 (IGF-1) signaling pathway has emerged as a promising therapeutic strategy. Linsitinib, an IGF-1 receptor (IGF-1R) inhibitor, has shown potential in disrupting this pathway. Additionally, metformin, commonly used in the treatment of type 2 diabetes, has been studied for its anti-cancer properties due to its ability to inhibit metabolic pathways that intersect with IGF-1 signaling, making it a candidate for combination therapy in cancer treatments. This study explores the anti-cancer effects of linsitinib and metformin on OVCAR3 cells by the suppression of the IGF-1 signaling pathway by siRNA-mediated IGF-1 gene silencing. The goal is to evaluate their efficacy as therapeutic agents and to emphasize the critical role of this pathway in OC cell proliferation. Cellular viability was evaluated by resazurin-based assay, and apoptosis was assessed by flux cytometry. The results of this study indicate that the combination of linsitinib and metformin exhibits an antagonistic effect (obtained by SynergyFinder 2.0 Software), reducing their anti-neoplastic efficacy in OC cell lines. Statistical analyses were performed using ordinary one-way or two-way ANOVA, followed by Tukey's or Šídák's multiple comparison tests. While linsitinib shows promise as a therapeutic option for OC, further research is needed to identify agents that could synergize with it to enhance its therapeutic efficacy, like the combination with standard chemotherapy in OC (carboplatin and paclitaxel).

Tumor Cytobiology of IGF-1R in Breast Tumor Activation and Propagation; And the Role of Celecoxib in its Inhibition

The Insulin-like Growth Factor 1 Receptor (IGF-1R) stands as a central orchestrator in cellular signaling, governing pivotal processes encompassing growth, proliferation, and differentiation. Its aberrant activation is intricately intertwined with the pathogenesis and progression of breast cancer, a heterogeneous disease presenting formidable clinical challenges. Amidst the burgeoning landscape of therapeutic interventions, Celecoxib, a nonsteroidal anti-inflammatory drug (NSAID), has emerged as a promising candidate for targeting the dysregulated IGF-1R pathway. This review delineates the intricate molecular mechanisms underlying Celecoxib's modulation of the IGF-1R pathway, elucidating its pharmacokinetic properties and therapeutic implications in breast cancer management. Celecoxib exerts inhibitory effects on IGF-1R through multifaceted molecular interactions, impeding receptor activation and downstream signaling cascades pivotal for tumor proliferation and metastasis. Furthermore, it regulates IGF-1R expression at both transcriptional and translational levels, exerting nuanced control over cellular responses. Moreover, Celecoxib's therapeutic impact transcends mere IGF-1R inhibition, as it potentiates pro-apoptotic pathways and disrupts tumor-permissive microenvironments. A nuanced understanding of Celecoxib's pharmacokinetic profile is imperative, considering its sustained and targeted inhibition of IGF-1R signaling, and its potential synergistic effects in combinatorial therapeutic regimens for breast cancer. This comprehensive elucidation underscores the paramount importance of deciphering Celecoxib's intricate molecular interplay with the IGF-1R pathway, heralding novel avenues for precision medicine and tailored therapeutic interventions in the management of breast cancer.

Follistatin drives neuropathic pain in mice through IGF1R signaling in nociceptive neurons.

Neuropathic pain is a debilitating chronic condition that lacks effective treatment. The role of cytokine- and chemokine-mediated neuroinflammation in its pathogenesis has been well documented. Follistatin (FST) is a secreted protein known to antagonize the biological activity of cytokines in the transforming growth factor-β (TGF-β) superfamily. The involvement of FST in neuropathic pain and the underlying mechanism remain largely unknown. Here, we report that FST was up-regulated in A-fiber sensory neurons after spinal nerve ligation (SNL) in mice. Inhibition or deletion of FST alleviated neuropathic pain and reduced the nociceptive neuron hyperexcitability induced by SNL. Conversely, intrathecal or intraplantar injection of recombinant FST, or overexpression of FST in the dorsal root ganglion (DRG) neurons, induced pain hypersensitivity. Furthermore, exogenous FST increased neuronal excitability in nociceptive neurons. The biolayer interferometry (BLI) assay and coimmunoprecipitation (co-IP) demonstrated direct binding of FST to the insulin-like growth factor-1 receptor (IGF1R), and IGF1R inhibition reduced FST-induced activation of extracellular signal-regulated kinase (ERK) and protein kinase B (AKT), as well as neuronal hyperexcitability. Further co-IP analysis revealed that the N-terminal domain of FST exhibits the highest affinity for IGF1R, and blocking this interaction with a peptide derived from FST attenuated Nav1.7-mediated neuronal hyperexcitability and neuropathic pain after SNL. In addition, FST enhanced neuronal excitability in human DRG neurons through IGF1R. Collectively, our findings suggest that FST, released from A-fiber neurons, enhances Nav1.7-mediated hyperexcitability of nociceptive neurons by binding to IGF1R, making it a potential target for neuropathic pain treatment.

6822 Proptosis Improvement with Teprotumumab is Independent of Race, Ethnicity, Gender and Age from Three Global Randomized, Double-Masked, Placebo-Controlled Trials of Patients with Acute Thyroid Eye Disease (TED)

Abstract Disclosure: G.J. Kahaly: Consulting Fee; Self; Amgen Inc. Research Investigator; Self; Amgen Inc. S.T. Wester: Advisory Board Member; Self; Amgen Inc. Consulting Fee; Self; Immunovant, Lassen. Research Investigator; Self; Amgen Inc, Sling Therapeutics, Immunovant. C.Y. Liu: Other; Self; royalties from Wolters Kluwers Health. H. Kate: Employee; Self; Amgen Inc. Stock Owner; Self; Amgen Inc. E. Conrad: Employee; Self; Amgen Inc. Stock Owner; Self; Amgen Inc. R.J. Holt: Employee; Self; Amgen Inc. Stock Owner; Self; Amgen Inc. Y. Hiromatsu: Advisory Board Member; Self; Amgen Inc. Consulting Fee; Self; Amgen Inc. Research Investigator; Self; Amgen Inc. Introduction: Thyroid eye disease (TED) produces orbital tissue expansion, inflammation, proptosis (eye bulging) and diplopia (double vision), causing eye pain and appearance/visual changes. Teprotumumab, an insulin-like growth factor-1 receptor inhibitor, significantly improved signs and symptoms of TED in three placebo-controlled trials in patients with high inflammation. Here, we report pooled proptosis response in patient subgroups. Methods: Patients ≥18 years old from three placebo-controlled trials, two in the US and EU (NCT01868997, NCT03298867) and one in Japan (OPTIC-J; jRCT2031210453), with Graves’ disease and recent onset (≤9 month duration) active TED (Clinical activity score, CAS≥4, ≥3 for OPTIC-J) were included. Patients received eight infusions of teprotumumab or placebo over 21 weeks, with the final study visit at Week 24 (three weeks after final dose). Observed proptosis response, defined as ≥2 mm improvement from baseline in study eye without deterioration ≥2 mm in fellow eye at Week 24, versus placebo is reported by tobacco use (yes/no), race (White or Asian), and age (<65/≥65). Cochran-Mantel-Haenszel tests compared teprotumumab and placebo subgroups. Results: Of 111 teprotumumab and 114 placebo patients, 68.5% (76) and 76.3% (87) were female, respectively; mean (SD) age 50.3 (12.4) and 51.1 (13.1) years, respectively; mean (SD) TED duration 5.49 (2.32) and 5.98 (2.40) months, respectively; and 78.4% (87) and 73.7% (84) were never/former smokers, respectively. In the overall population, 80.2% (89/111) of teprotumumab patients and 14.0% (16/114) of placebo patients had a proptosis response (P<.0001). At Week 24, 70.8% (17/24) of teprotumumab and 23.3% (7/30) placebo smokers were proptosis responders; in non-smokers, 82.8% (72/87) of teprotumumab and 10.7% (9/84) placebo patients were proptosis responders (P<.0001 for both). In White patients, 78.9% (56/71) of teprotumumab and 15.8% (12/76) of placebo patients were proptosis responders; in Asian patients, 90.0% (27/30) of teprotumumab and 10.0% (3/30) of placebo patients were responders (P<.0001 for both). In patients <65 years, 79.2% (76/96) teprotumumab patients and 13.4% (13/97) placebo patients were responders; in patients ≥65 years, 86.7% (13/15) teprotumumab and 17.6% (3/17) placebo were responders (P<.0001 for both). Conclusions: Subgroup analysis of proptosis response by tobacco use, race, and age showed that teprotumumab treatment led to significantly higher proptosis response versus placebo in all groups. Public Presentation: 6/1/2024

8518 Prevalence of Hearing Dysfunction in Patients with Autoimmune Thyroid Disorders, Thyroid Eye Disease and the General US population: A Claims Database Analysis

Abstract Disclosure: T.J. Smith: Consulting Fee; Self; Amgen Inc, Viridian, Minghui, Lassen, Lundbeck. Other; Self; US patents covering the use of IGF-1 receptor inhibitors in TED which are held by UCLA and the Lundquist Institute. A. Meyers: Employee; Self; Amgen Inc. Stock Owner; Self; Amgen Inc. Q. Fu: Stock Owner; Self; Amgen Inc. Other; Self; Amgen Inc, former employee. R.J. Holt: Employee; Self; Amgen Inc. Stock Owner; Self; Amgen Inc. K. Zhu: Employee; Self; Amgen Inc. Stock Owner; Self; Amgen Inc. Background: Autoimmune thyroid conditions including Graves’ disease (GD) have been associated with hearing impairment.([1]-3) Approximately 90% of patients (pts) with thyroid eye disease (TED) have hyperthyroidism/GD. Teprotumumab, an insulin-like growth factor-I receptor inhibitor, significantly improves TED signs/symptoms and became the first FDA-approved treatment for TED in 2020. Hearing-related adverse events were identified in pivotal trials of teprotumumab in TED.4 This epidemiology study aims to describe the prevalence of hearing loss/ototoxicity via claims data in commercially insured pts with autoimmune thyroid conditions, TED, and those receiving teprotumumab, as well as the general population (gen pop). Methods: Five mutually exclusive cohorts were created using deidentified claims data (Merative MarketScan®): GD pts (index is first GD diagnosis [dx] code), TED pts (index is later of both GD dx or eye symptom codes within 1 yr), teprotumumab pts (index is first claim for teprotumumab), other Thyroid Disorders (TD) pts (index is TD dx), and gen pop pts. Pts with teprotumumab claim were excluded from other cohorts. Eligible pts were ≥18 years (yrs) of age, continuously enrolled for ≥6 months pre and post index, between 1/1/2020-12/21/2021. Demographics (age, sex) were described between the cohorts and the gen pop. Proportions of pts with inpatient and outpatient claims for hearing loss/ototoxicity claims and proportions with hearing loss/ototoxicity claims in the 3 yrs preceding index were calculated. Age-standardized prevalence was presented using gen pop as the reference. Results: Of 21,256,714 eligible pts, 82,629 GD, 4,455 TED, 2,758 teprotumumab, 1,261,250 TD and 4,857,408 gen pop pts were identified. 47% pts in the gen pop cohort were female vs 72.1-75.7% in the other cohorts. Gen pop cohort was younger (mean [SD] age: 53 [15.1] yrs) vs 58.0-61.5 [15.1-15.6] yrs in other cohorts. Age-standardized prevalence of hearing loss/ototoxicity claims on/after index date was 3.3% for GD, 5.2% for TED, 4.3% for teprotumumab, 3.9% for TD, and 3.9% for gen pop pts. Hearing loss/ototoxicity claims were prevalent in the 3 years prior to index among these patients: 30.8% GD, 36.6% TED, 35.4% teprotumumab, 31.5% TD, and 27.3%) gen pop pts had a hearing loss/ototoxicity claim. Conclusions: In this descriptive unadjusted analysis, we observed similar prevalence of hearing loss/ototoxicity claims across thyroid disorders, TED pts, teprotumumab pts, and the gen pop group. Between 27%-37% had claims prior to thyroid diagnosis or receiving teprotumumab. It is expected that future analyses could adjust the rates for potential confounders across cohorts.

12231 PAPP-A As A Potential Target In Thyroid Eye Disease

Abstract Disclosure: C.A. Conover: None. L.K. Bale: None. D. Hamadi: None. M. Stan: ; Tourmaline, Genentech, Third Rock Ventures, ArgenX, Septerna, OrthoDi. ; Horizon, Immunovant, Lassen, Sling. Background: Proptosis in Thyroid Eye Disease (TED) can result in facial disfigurement and visual dysfunction. Studies revealed an interaction between thyroid-stimulating hormone receptor (TSHR) and insulin-like growth factor-I receptor (IGF-IR) that is essential in promoting TED pathogenesis. Treatment with Insulin-like growth factor I receptor (IGF-IR) inhibitors has been shown to be effective in reducing proptosis but with side effects. PAPP-A is metalloprotease that can increase pericellular IGF bioavailability through specific cleavage of inhibitory IGF binding proteins, in particular IGFBP-4. We propose that inhibition of IGF-IR indirectly and more selectively with PAPP-A inhibitory antibodies attenuates IGF-IR signaling in TED with fewer side effects. Methods: Informed consent was obtained from TED patients undergoing surgery in Mayo Clinic operating suites in Rochester, MN. Retro-orbital tissue was collected from 19 TED patients and 2 control subjects for fibroblast isolation and culture and was performed in a sterile tissue culture facility. TED and control fibroblasts were treated with pro-inflammatory cytokines, and flow separation of CD34- and CD34+ orbital fibroblasts was done, the latter representing infiltrating fibrocytes into the orbit in TED. Main outcome measured were PAPP-A expression and proteolytic activity, IGF-I stimulation of phosphatidylinositol 3 kinase/Akt pathway and inhibition by immuno-neutralizing antibodies against PAPP-A, CD34+ status and associated PAPP-A and IGF-IR expression. Results: Primary cultured cells showed that PAPP-A is expressed in orbital fibroblasts from TED patients but not in control subject fibroblasts and were markedly increased by pro-inflammatory cytokines stimulation. IGF-IR expression was not affected by cytokine treatment. Inhibition of PAPP-A’s proteolytic activity suppressed IGF-IR activation in orbital fibroblasts from TED patients. CD34+ orbital fibroblasts represent 80% of cells in culture from TED patients, and approximately 70% of these cells were accountable for PAPP-A and IGF-IR expression. Conclusion: These results support a role for PAPP-A in TED pathogenesis and indicate the potential for novel therapeutic targeting of the IGF axis. Presentation: 6/2/2024

6814 Durability of Teprotumumab for the Treatment of Thyroid Eye Disease (TED) in Clinical Trials

Abstract Disclosure: G.J. Kahaly: Consulting Fee; Self; Amgen Inc. Research Investigator; Self; Amgen Inc. P.S. Subramanian: Consulting Fee; Self; Amgen Inc. Research Investigator; Self; Amgen Inc. E. Conrad: Employee; Self; Amgen Inc. Stock Owner; Self; Amgen Inc. R.J. Holt: Employee; Self; Amgen Inc. Stock Owner; Self; Amgen Inc. T.J. Smith: Consulting Fee; Self; Amgen Inc, Viridian, Minghui, Lassen, Lundbeck. Other; Self; US patents covering the use of IGF-1 receptor inhibitors in TED which are held by UCLA and the Lundquist Institute. Introduction: Teprotumumab has demonstrated efficacy for the treatment of thyroid eye disease (TED). To assess durability of responses to teprotumumab over the longer term, pooled clinical trial data were assessed beyond the 24-week treatment period for patients in phase 2, OPTIC, and OPTIC-X studies who received a full course of teprotumumab. Methods: Observed rates for clinical activity score (CAS, ≥2 point improvement), EUGOGO-recommended composite response, diplopia (≥1 Gorman grade improvement), proptosis (≥2 mm improvement), and Overall responder status (≥2 mm improvement proptosis and ≥2 point improvement CAS) were assessed and pooled from study baseline to Week 24 (formal study) and up to Week 72 (51 weeks post-final teprotumumab infusion). Graves’ ophthalmopathy quality-of-life (GO-QOL) scores were also examined. Additional therapies for TED administered up to Week 120 (i.e., 99 weeks post-therapy) were assessed for evidence of persistent benefit from Week 24 through Week 120. Studies differed in the timing of follow-up visits. Data were not available at every time point for all patients. Results: Response rates among patients receiving a full (8-infusion) course of teprotumumab (N=112) were largely maintained 51 weeks after the final teprotumumab infusion at study Week 72: CAS 52/57 (91.2%); composite 51/57 (89.5%); diplopia 35/48 (72.9%); proptosis 38/56 (67.9%); and Overall 37/56 (66.1%). The mean reduction in proptosis was 2.68 (SD 1.92) mm (N=56), mean GO-QOL reduction was 15.22 (SE 2.82, N=56), and disease inactivation (CAS ≤1) was detected in 40/57 (70.2%). Post-teprotumumab treatment, 17.9% (19/106) of reporting patients received additional TED treatment (systemic steroids or teprotumumab) and/or remedial periocular surgery as of 99 weeks after the last dose (to study Week 120). Conclusions: At Week 72, nearly one-year posttherapy, responses to teprotumumab were similar to those at Week 24 formal study end. Both CAS and ophthalmic composite responses were observed in 90% of observed patients. Diplopia and proptosis responses were seen in almost 70%. Additionally, 82% of patients did not require additional treatment for TED nearly two years after therapy completion. Public Presentation: 6/2/2024

Long-Term Efficacy of Teprotumumab in Thyroid Eye Disease: Follow-Up Outcomes in Three Clinical Trials.

Introduction: Thyroid eye disease (TED) is an autoimmune process characterized by extraocular muscle and orbital fat remodeling/expansion resulting in swelling, pain, redness, proptosis, and diplopia. Teprotumumab, an insulin-like growth factor-I receptor inhibitor, demonstrated improvements in TED signs and symptoms in three adequately powered clinical trials of 24 weeks duration. Here we analyze the long-term maintenance of responses with teprotumumab from these trials. Methods: A total of 112 patients who received 7 or 8 infusions of teprotumumab in the Phase 2, Phase 3 (OPTIC study), and OPTIC Extension (OPTIC-X) studies were included in this analysis. Responses, including clinical activity score (CAS ≥2-point improvement), the European Group of Graves' Orbitopathy ophthalmic composite outcome, diplopia (≥1 Gorman grade improvement), proptosis (≥2 mm improvement), Overall (improvement in proptosis + CAS), and disease inactivation (CAS ≤1), were assessed and pooled from study baseline to week 24 (formal study) and up to week 72 (formal follow-up). Graves' Ophthalmopathy quality-of-life (GO-QoL) scores were also assessed. Outcomes included the percentages of observed patient responsesfrom the study baseline. Additional alternative treatments for TED were assessed as a surrogate of persistent benefit from week 24 through week 120 (extended follow-up). Studies differed in the timing of follow-up visits, and data from some visits were unavailable. Results: At week 72, 52/57 (91.2%), 51/57 (89.5%), 35/48 (72.9%), 38/56 (67.9%), and 37/56 (66.1%) of patients were responders for CAS, composite outcome, diplopia, proptosis, and Overall response, respectively. The mean reduction in proptosis was 2.68 mm (SD 1.92, n = 56), mean GO-QoL improvement was 15.22 (SE 2.82, n = 56), and disease inactivation (CAS ≤1) was detected in 40/57 (70.2%). Over 99 weeks following teprotumumab therapy, 19/106 (17.9%) patients reported additional TED therapy during formal and extended follow-up. Conclusion: The long-term response to teprotumumab as observed 51 weeks after therapy was similar to week 24 results in the controlled clinical trials. Inflammatory and ophthalmic composite outcome improvements were seen in 90% of patients with nearly 70% reporting improvement in diplopia and proptosis. Further, 82% of patients in this analysis did not report additional TED treatment (including surgery) over 99 weeks following the final teprotumumab dose.

PAPP-A as a Potential Target in Thyroid Eye Disease.

Proptosis in thyroid eye disease (TED) can result in facial disfigurement and visual dysfunction. Treatment with insulin-like growth factor I receptor (IGF-IR) inhibitors has been shown to be effective in reducing proptosis but with side effects. To test the hypothesis that inhibition of IGF-IR indirectly and more selectively with PAPP-A inhibitors attenuates IGF-IR signaling in TED. Informed consent was obtained from patients with TED undergoing surgery, and retro-orbital tissue was collected for fibroblast isolation and culture. Operations were performed in Mayo Clinic operating suites. Cell culture was performed in a sterile tissue culture facility. Retro-orbital tissue was collected from 19 patients with TED. Treatment of TED fibroblasts with proinflammatory cytokines. Flow separation of CD34- and CD34+ orbital fibroblasts, the latter representing infiltrating fibrocytes into the orbit in TED. PAPP-A expression and proteolytic activity, IGF-I stimulation of phosphatidylinositol 3 kinase/Akt pathway, and inhibition by immuno-neutralizing antibodies against PAPP-A, CD34+ status, and associated PAPP-A and IGF-IR expression were measured. Proinflammatory cytokines markedly increased PAPP-A expression in TED fibroblasts. IGF-IR expression was not affected by cytokine treatment. Inhibition of PAPP-A's proteolytic activity suppressed IGF-IR activation in orbital fibroblasts from patients with TED. TED fibroblasts that were CD34+ represented ∼80% of the cells in culture and accounted for ∼70% of PAPP-A and IGF-IR-expressing cells. These results support a role for PAPP-A in TED pathogenesis and indicate the potential for novel therapeutic targeting of the IGF axis.

Contrasting consequences of podocyte insulin-like growth factor 1 receptor inhibition

Insulin signaling to the glomerular podocyte via the insulin receptor (IR) is critical for kidney function. In this study we show that near-complete knockout of the closely related insulin-like growth factor 1 receptor (IGF1R) in podocytes is detrimental, resulting in albuminuria invivo and podocyte cell death invitro. In contrast, partial podocyte IGF1R knockdown confers protection against doxorubicin-induced podocyte injury. Proteomic analysis of cultured podocytes revealed that while near-complete loss of podocyte IGF1R results in the downregulation of mitochondrial respiratory complex I and DNA damage repair proteins, partial IGF1R inhibition promotes respiratory complex expression. This suggests that altered mitochondrial function and resistance to podocyte stress depends on the level of IGF1R suppression, the latter determining whether receptor inhibition is protective or detrimental. Our work suggests that the partial suppression of podocyte IGF1R could have therapeutic benefits in treating albuminuric kidney disease.

Abstract 707: Calorie restriction to augment radiation response in models of Black women with breast cancer

Abstract Introduction: Black women have higher mortality from breast cancer (BrCa) than other populations. While several factors contribute to this disparity, insulin-like growth factor 1 receptor (IGF-1R), is notably overexpressed in tumors originating in Black women compared to White women, which is associated with tumor progression and resistance to radiation therapy (RT). Caloric restriction (CR) is noted to reduce the expression of members of the IGF-1R pathway. We hypothesize that CR increases the efficacy of RT, in Black women, by downregulating the IGF-1R pathway to decrease tumor growth. Methods: To understand the feasibility of implementing CR in Black women with BrCa, patients received a CR diet during adjuvant breast RT on an IRB approved investigator-initiated clinical trial and pre- and post- measures were evaluated. BrCa cell lines originating from Black (MD-MBA-468 and MD-MBA-157) or White patients (MDA-MB-231 and MDA-MB-436) were exposed to RT in the presence and absence of CR medium, IGF-1 to upregulate the pathway, and PPP, an IGF-1R inhibitor to evaluate the role of dietary interventions and IGF-1R pathway modulation in altering the RT response. Finally, human BrCa tissue was collected and ex vivo explants were used to evaluate the role of diet to augment the RT response. Results: In the pilot clinical trial, 32 patients were enrolled, 50% of whom were Black (16B/16W). Black patients had more adverse baseline physiologic parameters and corresponding higher insulin and systemic inflammation as measured by ESR, IFNγ, Il-1β, and TNFα at baseline. Adherence to CR was 87.3% for the Black patients who had an average weight loss of 7.33 lbs, and decreased insulin and cholesterol levels after CR+RT. In intro, in Black originating cells, cell viability experiments showed that CR+RT decreased cell viability by 53% & 46% while RT alone reduced viability by 32 & 41%. In White originating cells, CR+RT decreased cell viability by 52% and 53% while RT alone reduced viability by 42% and 26%. IGF-1R inhibition with PPP caused a more significant decrease in viability when given with RT than CR+RT did. The opposite effect was noted when IGF-1 was added to the cell lines and that increase was prevented by treatment with IGF-1+RT+CR. This was confirmed in vivo. Explants revealed CR helped decrease proliferation and increase apoptosis for all cancer patients. Conclusion: Taken together, these data demonstrate that Black patients can adhere to dietary interventions during RT therapy for breast cancer which may help achieve better tumor control via downregulation of the IGF-1R pathway which is often notably upregulated in this population. This benefit is widely applicable with equivalent efficacy between patients of both races and all breast cancer subtypes. Future studies should investigate the role of downregulating IGF-1R via dietary interventions to narrow disparities in breast cancer outcomes in our black patient population. Citation Format: Noelle B. Francois, Anuradha A. Shastri, Siani Harding, Tiziana DeAngelis, Adeseye Adekeye, Nicole Simone. Calorie restriction to augment radiation response in models of Black women with breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 707.

Role of Insulin-like Growth Factor-1 Receptor in Tobacco Smoking-Associated Lung Cancer Development.

Cancer remains a significant global health concern, with lung cancer consistently leading as one of the most common malignancies. Genetic aberrations involving receptor tyrosine kinases (RTKs) are known to be associated with cancer initiation and development, but RTK involvement in smoking-associated lung cancer cases is not well understood. The Insulin-like Growth Factor 1 Receptor (IGF-1R) is a receptor that plays a critical role in lung cancer development. Its signaling pathway affects the growth and survival of cancer cells, and high expression is linked to poor prognosis and resistance to treatment. Several reports have shown that by activating IGF-1R, tobacco smoke-related carcinogens promote lung cancer and chemotherapy resistance. However, the relationship between IGF-1R and cancer is complex and can vary depending on the type of cancer. Ongoing investigations are focused on developing therapeutic strategies to target IGF-1R and overcome chemotherapy resistance. Overall, this review explores the intricate connections between tobacco smoke-specific carcinogens and the IGF-1R pathway in lung carcinogenesis. This review further highlights the challenges in using IGF-1R inhibitors as targeted therapy for lung cancer due to structural similarities with insulin receptors. Overcoming these obstacles may require a comprehensive approach combining IGF-1R inhibition with other selective agents for successful cancer treatment.

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase suppresses insulin-like growth factor 1 receptor expression to inhibit cell adhesion and proliferation in gastric cancer.

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) has recently emerged as a novel tumor suppressor. Researchers have observed that LHPP plays a crucial role in inhibiting proliferation, growth, migration, invasion, and cell metabolism across various cancers. Nevertheless, the specific functions and underlying mechanisms of LHPP as a tumor suppressor in gastric cancer (GC) require further exploration. The expression of LHPP was assessed in human GC specimens and cell lines. Various assays were employed to evaluate the impact of LHPP on GC cells. RNA sequencing and Gene Set Enrichment Analysis were conducted to unravel the mechanism through which LHPP regulates GC cell behavior. Additionally, xenograft nude mouse models were utilized to investigate the in vivo effects of LHPP. The findings indicate that LHPP, functioning as a tumor suppressor, is downregulated in both GC tissues and cells. LHPP emerges as an independent risk factor for GC patients, and its expression level exhibits a positive correlation with patient prognosis. LHPP exerts inhibitory effects on the adhesion and proliferation of GC cells by suppressing the expression of insulin-like growth factor 1 receptor (IGF1R) and modulating downstream signaling pathways. Consequently, LHPP holds potential as a biomarker for targeted therapy involving IGF1R inhibition in GC patients.

The in vitro and in vivo antiviral effects of IGF1R inhibitors against respiratory syncytial virus infection

The insulin-like growth factor 1 receptor (IGF1R) was recognized as a pivotal receptor that facilitated the cellular entry of RSV. Small molecule inhibitors designed to target IGF1R exhibited potential as potent antiviral agents. Through virtual screening, we conducted a screening process involving small molecule compounds derived from natural products, aiming to target the IGF1R protein against respiratory syncytial virus infection. The molecular dynamics simulation analysis showed that tannic acid and daptomycin interacted with the IGF1R. The experimental results in vivo and in vitro showed that tannic acid and daptomycin had anti-RSV infection potential through reducing viral loads, inflammation, airway resistance and protecting alveolar integrity. The CC50 values of tannic acid and daptomycin were 6 nM and 0.45 μM, respectively. Novel small-molecule inhibitors targeting the IGF1R, tannic acid and daptomycin, may be effective anti-RSV therapy agents. This study may in future broaden the arsenal of therapeutics for use against RSV infection and lead to more effective care against the virus. Communicated by Ramaswamy H. Sarma

Glycemic Trends in Patients with Thyroid Eye Disease Treated with Teprotumumab in 3 Clinical Trials

ObjectiveAssess incidence, severity, and outcomes of serum glucose excursions in patients with thyroid eye disease who received the insulin-like growth factor-1 receptor inhibitor, teprotumumab, during pivotal clinical trials. DesignAnalysis of pooled glycemic data and longitudinal trends. Subjectsphase 2 and phase 3 (OPTIC) pooled analysis: 170 patients (84 teprotumumab, 86 placebo); OPTIC-X: 51 patients from OPTIC. MethodsTeprotumumab administered as 8 intravenous infusions over 21 weeks. In the phase 2 trial, serum glucose was measured at weeks 1, 4, 15, and 21, with fasting blood collections weeks 1 and 4. In OPTIC and OPTIC-X, serum glucose was measured at each study visit, with fasting draws weeks 1 and 4 (non-diabetic patients) or all visits (diabetic patients). In all studies, hemoglobin A1c (HbA1c) was measured at baseline, 12, and 24 weeks plus weeks 36 and 48 of OPTIC-X. Main Outcome MeasuresSerum glucose and HbA1c over time. ResultsIn the pooled analysis, 9 hyperglycemic episodes were reported in 8 teprotumumab patients; mean HbA1c in teprotumumab patients increased 0.22% from baseline to week 24 (to 5.8%, range 5.0%–7.9%) versus 0.04% in placebo patients (to 5.6%, range 4.6%–8.1%). At study end, 78% of teprotumumab and 87% of placebo patients were normoglycemic. Normoglycemia was maintained from baseline to week 24 in 84% (57/68) of teprotumumab and 93% (64/69) of placebo patients. Of prediabetic patients, 43% (3/7) remained prediabetic in both groups and 29% (2/7) of teprotumumab and 14% (1/7) of placebo patients were diabetic at week 24. OPTIC-X showed a trend toward increased fasting glucose and HbA1c during teprotumumab retreatment and initial therapy (placebo patients from OPTIC). Fasting glucose commonly rose following the first 2-3 infusions and stabilized over subsequent infusions. Most hyperglycemic incidents occurred in patients with baseline prediabetes or diabetes and were controlled with medication. There was no evidence of progression or increased incidence of hyperglycemia with subsequent doses. ConclusionsSerious glycemic excursions are uncommon in patients who are normoglycemic before teprotumumab therapy. Patients with controlled diabetes or impaired glucose tolerance can be treated safely if baseline screening, regular monitoring of glycemic control, and treatment of hyperglycemia are ensured.

A viral insulin-like peptide inhibits IGF-1 receptor phosphorylation and regulates IGF1R gene expression

ObjectiveThe insulin/IGF superfamily is conserved across vertebrates and invertebrates. Our team has identified five viruses containing genes encoding viral insulin/IGF-1 like peptides (VILPs) closely resembling human insulin and IGF-1. This study aims to characterize the impact of Mandarin fish ranavirus (MFRV) and Lymphocystis disease virus-Sa (LCDV-Sa) VILPs on the insulin/IGF system for the first time. MethodsWe chemically synthesized single chain (sc, IGF-1 like) and double chain (dc, insulin like) forms of MFRV and LCDV-Sa VILPs. Using cell lines overexpressing either human insulin receptor isoform A (IR-A), isoform B (IR-B) or IGF-1 receptor (IGF1R), and AML12 murine hepatocytes, we characterized receptor binding, insulin/IGF signaling. We further characterized the VILPs’ effects of proliferation and IGF1R and IR gene expression, and compared them to native ligands. Additionally, we performed insulin tolerance test in CB57BL/6 J mice to examine in vivo effects of VILPs on blood glucose levels. Finally, we employed cryo-electron microscopy (cryoEM) to analyze the structure of scMFRV-VILP in complex with the IGF1R ectodomain. ResultsVILPs can bind to human IR and IGF1R, stimulate receptor autophosphorylation and downstream signaling pathways. Notably, scMFRV-VILP exhibited a particularly strong affinity for IGF1R, with a mere 10-fold decrease compared to human IGF-1. At high concentrations, scMFRV-VILP selectively reduced IGF-1 stimulated IGF1R autophosphorylation and Erk phosphorylation (Ras/MAPK pathway), while leaving Akt phosphorylation (PI3K/Akt pathway) unaffected, indicating a potential biased inhibitory function. Prolonged exposure to MFRV-VILP led to a significant decrease in IGF1R gene expression in IGF1R overexpressing cells and AML12 hepatocytes. Furthermore, insulin tolerance test revealed scMFRV-VILP's sustained glucose-lowering effect compared to insulin and IGF-1. Finally, cryo-EM analysis revealed that scMFRV-VILP engages with IGF1R in a manner closely resembling IGF-1 binding, resulting in a highly analogous structure. ConclusionsThis study introduces MFRV and LCDV-Sa VILPs as novel members of the insulin/IGF superfamily. Particularly, scMFRV-VILP exhibits a biased inhibitory effect on IGF1R signaling at high concentrations, selectively inhibiting IGF-1 stimulated IGF1R autophosphorylation and Erk phosphorylation, without affecting Akt phosphorylation. In addition, MFRV-VILP specifically regulates IGF-1R gene expression and IGF1R protein levels without affecting IR. CryoEM analysis confirms that scMFRV-VILP’ binding to IGF1R is mirroring the interaction pattern observed with IGF-1. These findings offer valuable insights into IGF1R action and inhibition, suggesting potential applications in development of IGF1R specific inhibitors and advancing long-lasting insulins.