Insulin-like Growth Factor Receptor Research Articles

Targeting IGF-IR improves neoadjuvant chemotherapy efficacy in breast cancers with low IGFBP7 expression

There has been a long-standing interest in targeting the type 1 insulin-like growth factor receptor (IGF-1R) signaling system in breast cancer due to its key role in neoplastic proliferation and survival. However, no IGF-1R targeting agent has shown substantial clinical benefit in controlled phase 3 trials, and no biomarker has been shown to have clinical utility in the prediction of benefit from an IGF-1R targeting agent. IGFBP7 is an atypical insulin-like growth factor binding protein as it has a higher affinity for the IGF-1R than IGF ligands. We report that low IGFBP7 gene expression identifies a subset of breast cancers for which the addition of ganitumab, an anti-IGF-1R monoclonal antibody, to neoadjuvant chemotherapy, substantially improved the pathological complete response rate compared to neoadjuvant chemotherapy alone. The pCR rate in the chemotherapy plus ganitumab arm was 46.9% in patients in the lowest quartile of IGFBP7 expression, in contrast to only 5.6% in the highest quartile. Furthermore, high IGFBP7 expression predicted increased distant metastasis risk. If our findings are confirmed, decisions to halt the development of IGF-1R targeting drugs, which were based on disappointing results of prior trials that did not use predictive biomarkers, should be reviewed.

Unveiling the role of IGF1R in autism spectrum disorder: a multi-omics approach to decipher common pathogenic mechanisms in the IGF signaling pathway.

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition marked by impairments in social interaction, communication, and repetitive behaviors. Emerging evidence suggests that the insulin-like growth factor (IGF) signaling pathway plays a critical role in ASD pathogenesis; however, the precise pathogenic mechanisms remain elusive. This study utilizes multi-omics approaches to investigate the pathogenic mechanisms of ASD susceptibility genes within the IGF pathway. Whole-exome sequencing (WES) revealed a significant enrichment of rare variants in key IGF signaling components, particularly the IGF receptor 1 (IGF1R), in a cohort of Chinese Han individuals diagnosed with ASD, as well as in ASD patients from the SFARI SPARK WES database. Subsequent single-cell RNA sequencing (scRNA-seq) of cortical tissues from children with ASD demonstrated elevated expression of IGF receptors in parvalbumin (PV) interneurons, suggesting a substantial impact on their development. Notably, IGF1R appears to mediate the effects of IGF2R on these neurons. Additionally, transcriptomic analysis of brain organoids derived from ASD patients indicated a significant association between IGF1R and ASD. Protein-protein interaction (PPI) and gene regulatory network (GRN) analyses further identified ASD susceptibility genes that interact with and regulate IGF1R expression. In conclusion, IGF1R emerges as a central node within the IGF signaling pathway, representing a potential common pathogenic mechanism and therapeutic target for ASD. These findings highlight the need for further investigation into the modulation of this pathway as a strategy for ASD intervention.

Fluorescent tagging of endogenous IRS2 with an auxin-dependent degron to assess dynamic intracellular localization and function

Insulin Receptor Substrate 2 (IRS2) is a signaling adaptor protein for the insulin (IR) and Insulin-like Growth Factor-1 (IGF-1R) receptors. In breast cancer, IRS2 contributes to both initiation of primary tumor growth and establishment of secondary metastases through regulation of cancer stem cell (CSC) function and invasion. However, how IRS2 mediates its diverse functions is not well understood. We used CRISPR/Cas9-mediated gene editing to modify endogenous IRS2 to study the expression, localization, and function of this adaptor protein. A cassette containing an auxin inducible degradation (AID) sequence, 3X-FLAG tag and mNeon-green was introduced at the N-terminus of the IRS2 gene to provide rapid and reversible control of IRS2 protein degradation and analysis of endogenous IRS2 expression and localization. Live fluorescence imaging of these cells revealed that IRS2 shuttles between the cytoplasm and nucleus in response to growth regulatory signals in a PI3K-dependent manner. Inhibition of nuclear export or deletion of a putative nuclear export sequence in the C-terminal tail promotes nuclear retention of IRS2, implicating nuclear export in the mechanism by which IRS2 intracellular localization is regulated. Moreover, the acute induction of IRS2 degradation reduces tumor cell invasion, demonstrating the potential for therapeutic targeting of this adaptor protein. Our data highlight the value of our model of endogenously tagged IRS2 as a tool to study IRS2 localization and function.

Astragalus Extract Mixture HT042 Alleviates Dexamethasone-Induced Bone Growth Retardation in Rat Metatarsal Bones.

The most widely used synthetic glucocorticoid, dexamethasone (DEX), causes stunted growth in children when used excessively or for long periods of time; however, there are still plenty of pediatric patients require long-term treatment with DEX. As an alternative, growth hormone is used in combination, but it has side effects, a high cost, and psychological factors, and it is not satisfactory in terms of effectiveness. It is necessary to develop a safe and affordable treatment that can replace it. The Korean Food and Drug Administration approved HT042, a standardized functional food ingredient, with the claim that it can help height growth of children. In this study, it was found that HT042 activated the Indian hedgehog/parathyroid hormone-related protein signaling pathway and enhanced the number of growth hormone receptors and insulin-like growth factor-1 receptors on the growth plate surface, which were reduced by DEX treatment, and restored growth retardation. In metatarsal bone and primary chondrocyte models, it was found that HT042 can promote the length of growth plate and recover DEX-induced growth retardation. It was also found that HT042 promotes cell proliferation using bromodeoxyuridine and terminal deoxynucleotidyl transferase dUTP nick end labeling assays; moreover, we verified increased expression of GHR/IGF-1R and Ihh/PTHrP pathway activity using qRT-PCR, western blotting, and siRNA analyses to verify its direct action on the growth plate. The anti-apoptotic effect of HT042 was identified by regulating the expression of apoptotic factors such as caspase-3, Bcl2, Bclx, and Bax. These results were identified using both ex vivo and in vitro models. Our study verified that co-administration of HT042 could recover the DEX induced growth retardation.

Epigallocatechin-3-gallate attenuates fluoride induced apoptosis via PI3K/FoxO1 pathway in ameloblast-like cells

Fluoride is a double-edged sword. It was widely used for early caries prevention while excessive intake caused a toxicology effect, affected enamel development, and resulted in dental fluorosis. The study aimed to evaluate the protective effect and mechanism of Epigallocatechin-3-gallate (EGCG) on the apoptosis induced by fluoride in ameloblast-like cells. We observed that NaF triggered apoptotic alterations in cell morphology, excessive NaF arrested cell cycle at the G1, and induced apoptosis by up-regulating Bax and down-regulating Bcl-2. NaF activated the insulin-like growth factor receptor (IGFR), and phosphatidylinositol-3-hydroxylase (p-PI3K), while dose-dependently down-regulating the expression of Forkhead box O1 (FoxO1). EGCG supplements reversed the changes in LS8 morphology, the cell cycle, and apoptosis induced by fluoride. These results indicated that EGCG possesses a protective effect against fluoride toxicity. Furthermore, EGCG suppressed the activation of p-PI3K and the down-regulation of FoxO1 caused by fluoride. Collectively, our findings suggested that EGCG attenuated fluoride-induced apoptosis by inhibiting the PI3K/FoxO1 signaling pathway. EGCG may serve as a new alternative method for dental fluorosis prevention, control, and treatment.

Research advances in insulin-like growth factor

Objective: The review aims to summarize the historical context, biological functions, and recent advancements in IGF research. Methods: A systematic literature search was conducted using PubMed with "Insulin-like Growth Factors" (IGFs) as the primary keyword. Relevant articles, including seminal studies and recent research papers, were selected and analyzed to gather comprehensive information on the IGF system. The review synthesizes findings from these sources to provide a detailed account of the IGF system's structure and function. Results: The review details the historical experiments that led to the identification of IGFs and highlights their structural similarities to insulin. It covers the molecular structure and gene sequences of IGFs, their distribution across various tissues, and the mechanisms through which they exert biological effects. The article also discusses the IGF receptors and binding proteins, emphasizing their roles in mediating IGF actions. The review identifies key areas of IGF research, including their involvement in growth, development, and disease processes such as cancer and metabolic disorders. Conclusions: IGF system plays a crucial role in regulating various physiological processes. Despite significant advancements in understanding IGF biology, further research is needed to elucidate the detailed mechanisms of IGF signaling and their implications in disease pathogenesis.

DRAIC mediates hnRNPA2B1 stability and m6A-modified IGF1R instability to inhibit tumor progression.

Type 1 insulin-like growth factor receptor (IGF1R) plays an important role in cancer, however, posttranscriptional regulation such as N6-methyladenosine (m6A) of IGF1R remains unclear. Here, we reveal a role for a lncRNA Downregulated RNA in Cancer (DRAIC) suppress tumor growth and metastasis in clear cell Renal Carcinoma (ccRCC). Mechanistically, DRAIC physically interacts with heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) and enhances its protein stability by blocking E3 ligase F-box protein 11 (FBXO11)-mediated ubiquitination and proteasome-dependent degradation. Subsequently, hnRNPA2B1 destabilizes m6A modified-IGF1R, leading to inhibition of ccRCC progression. Moreover, four m6A modification sites are identified to be responsible for the mRNA degradation of IGF1R. Collectively, our findings reveal that DRAIC/hnRNPA2B1 axis regulates IGF1R mRNA stability in an m6A-dependent manner and highlights an important mechanism of IGF1R fate. These findings shed light on DRAIC/hnRNPA2B1/FBXO11/IGF1R axis as potential therapeutic targets in ccRCC and build a link of molecular fate between m6A-modified RNA and ubiquitin-modified protein.

Structural Models for a Series of Allosteric Inhibitors of IGF1R Kinase.

The allosteric inhibition of insulin-like growth factor receptor 1 kinase (IGF1RK) is a potential strategy to overcome selectivity barriers for targeting receptor tyrosine kinases. We constructed structural models of a series of 12 indole-butyl-amine derivatives that have been reported as allosteric inhibitors of IGF1RK. We further studied the dynamics and interactions of each inhibitor in the allosteric pocket via all-atom explicit-solvent molecular dynamics (MD) simulations. We discovered that a bulky carbonyl substitution at the R1 indole ring is structurally unfavorable for inhibitor binding in the IGF1RK allosteric pocket. Moreover, we found that the most potent derivative (termed C11) acquires a distinct conformation: forming an allosteric pocket channel with better shape complementarity and interactions with the receptor. In addition to a hydrogen-bonding interaction with V1063, the cyano derivative C11 forms a stable hydrogen bond with M1156, which is responsible for its unique binding conformation in the allosteric pocket. Our findings show that the positioning of chemical substituents with different pharmacophore features at the R1 indole ring influences molecular interactions and binding conformations of indole-butyl-amine derivatives and, hence, dramatically affects their potencies. Our results provide a structural framework for the design of allosteric inhibitors with improved affinities and specificities against IGF1RK.

237 Disrupted insulin signaling due to an acute immune response in swine

Abstract Insulin is an anabolic hormone involved in glucose uptake and synthesis of fats, proteins, and glycogen. Altered insulin signaling can occur due to metabolic state, pathogen exposure, and autoimmune disorders. Lipopolysaccharide (LPS), an endotoxin secreted produced by gram-negative bacteria, can induce a severe, systemic immune response. In pigs, chronic LPS exposure has induced insulin resistance. However, the effects of acute exposure to LPS on insulin signaling and resistance have not been elucidated. Crossbred nursery pigs [n = 58, initial body weight (BW) = 12.1 kg ± 0.23 kg] were randomly assigned into two experimental subsets, where 10 animals were designated for repeated blood sampling and 48 animals underwent timed euthanasia for tissue collection. For repeated blood sampling, jugular catheters were placed under anesthesia and the animals were given 48 h to recover before being randomly assigned to treatments. These treatments were an intraperitoneal injection of either 15µg/kg BW LPS or an equal volume of 0.9% Saline (n = 5 pigs/treatment). Blood was collected for 48 h followed by euthanasia. The other 48 pigs were randomly assigned to the same treatments, and then randomly assigned to euthanasia timepoints of 0, 3, 6, 12, 24 or 48 h post injection for tissue collection. Among the catheterized pigs, 2-h post LPS challenge there was a decrease in serum insulin concentration (P < 0.05) and mild hyperglycemia (P < 0.05) post challenge. At 12- and 24-h post LPS challenge there was a decrease in insulin (P < 0.05) and a trend hyperglycemia was also apparent at 24 h (P = 0.063). In liver tissue, insulin related genes exhibited alterations post LPS injection. Phosphoinositide 3-kinase (pi3k) and insulin receptor substrate 1 (irs1) expression were decreased at 3 and 6 h (p< 0.05) and protein kinase b (akt) expression were decreased at 3 h (P < 0.05) post challenge. The expression of insulin inhibitor growth factor receptor bound protein 10 (grb10) was decreased at 6-, 12-, and 24-h after challenge (P < 0.05). Fructose-1-6-bisphosphatase (f16bp) expression was reduced at 3-, 6-, and 12-h (P < 0.05) in the liver while phosphoenolpyruvate carboxykinase (pepck) expression was decreased at 3- and 6-h (P < 0.01) post challenge. Other metabolic genes were decreased at 3-, 6-, and 12-h post LPS challenge, including fatty acid synthase (fas; P < 0.05), carbohydrate response element binding protein (chrebp; P < 0.05), and acetyl CoA carboxylase (acc; P < 0.05). Protein abundance of Akt 3 h after LPS injection was decreased in the liver (P < 0.05). In skeletal muscle 6 h post LPS injection, insulin receptor (insr), insulin-like growth factor receptor (igfr) and fas were all increased (P < 0.05) These results indicate disrupted insulin signaling at various levels after an acute immune response.

Abstract RF02-02: BBO-10203, a first-in-class, orally bioavailable, selective covalent small molecule that inhibits RAS-driven PI3Kalpha activity without affecting glucose metabolism

Abstract PI3Kα is the most mutated kinase and the second most mutated oncogene in human cancer. Activation of PI3Ka can be achieved by receptor tyrosine kinases such as insulin receptor and insulin-like growth factor receptor 1 and/or by directly interacting with RAS family members. Previous elegant preclinical studies have established that RAS-driven PI3Ka activation is important in tumor cells but may not be involved in cell types controlling glucose metabolism. Alpelisib, a small molecule inhibitor of the kinase activity of PI3Ka, has been approved for the treatment of ER+ PIK3CA mutant breast cancer in combination with fulvestrant after endocrine therapy in advanced or metastatic breast cancer based on an improvement in PFS versus fulvestrant alone. Inhibition of PI3Ka activity by alpelisib in normal tissues resulted in a severe (G3/4) hyperglycemia rate of 37% with frequent dose interruptions and discontinuations. Additionally, preclinical studies have demonstrated that the dysregulation of glucose homeostasis resulting from PI3Ka kinase inhibition leads to hyperinsulinemia that increases pathway flux, rendering kinase inhibitors less effective. Here, we report on a novel covalent small molecule designed to inhibit RAS-mediated activation of the AKT pathway via PI3Ka without the resultant hyperglycemia associated with direct inhibition of PI3Ka kinase activity. BBO-10203 disrupts the physical interaction between RAS and PI3Ka in tumor cells resulting in potent signaling pathway inhibition. This agent selectively binds to PI3Ka and disrupts its interaction with K-,H-, and N-RAS with low single digit nanomolar potency (~5 nM). Breaking the interaction between these two oncogenes inhibits basal pAKT cellular levels (BT-474/KYSE-410 IC50: ~5 nM) in HER2 amplified (HER2amp) and wild-type or mutant PI3Ka cell lines. Even though BBO-10203 does not inhibit the kinase activity of PI3Ka, its effects on cancer cell signaling inhibition and transcriptional regulation highly resemble those of alpelisib. BBO-10203 displays excellent drug-like properties and oral bioavailability. Single dose treatment of KYSE-410 (HER2amp/KRASG12C) tumor bearing mice with increasing doses (1-100 mg/kg, PO) of BBO-10203 results in dose and time dependent inhibition of pAKT in vivo. Maximal inhibition (~80%) is achieved at 30 mg/kg and lasts for 24 hours. Repeated dose treatment of tumor bearing mice with BBO-10203 is well tolerated and results in significant efficacy in PIK3CA mutant as well as HER2amp human xenograft models. In the KYSE-410 xenograft model, BBO-10203 daily oral dosing of 30 mg/kg results in significant tumor regressions. Importantly, treatment with BBO-10203 does not affect insulin signaling in differentiated adipocytes in vitro, nor does it impact glucose metabolism in vivo at 3-times the maximal efficacious dose level in xenograft studies. In conclusion, we have identified a novel approach to inhibit the PI3Ka signaling pathway by blocking its interaction with, and activation by RAS. This approach can achieve strong pAKT inhibition in tumor cells without changes in glucose metabolism. Clinical investigation of BBO-10203 for the treatment of both ER+/PIK3CA mutant and HER2amp breast cancer is warranted. Citation Format: Pedro Beltran, Simanshu Dhirendra, Rui Xu, Ming Chen, Daniel Czyzyk, Sofia Donovan, Siyu Feng, Cindy Feng, Lijuan Fu, Felice Lightstone, Ken Lin, Anna Maciag, Dwight Nissley, Erin Riegler, Kerstin Sinkevicius, Andrew Stephen, James Stice, David Turner, Bin Wang, Keshi Wang, Yue Yang, Cathy Zhang, Frank McCormick, Eli Wallace. BBO-10203, a first-in-class, orally bioavailable, selective covalent small molecule that inhibits RAS-driven PI3Kalpha activity without affecting glucose metabolism [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr RF02-02.

MiRNA-221 and -222 increase in exosomes upon insulin stimulation of human vascular smooth muscle cells lacking the insulin-like growth factor 1 receptor

As a result of increased vascular inflammation, patients with Type 2 diabetes experience a near 4-fold increase in their risk for heart attack and stroke. miR-221 and -222 are two microRNAs that are upregulated in the vasculature of Type 2 diabetic patients. miR-221/222 act by downregulating the cyclin-dependent kinase inhibitor, p27Kip1, in vascular smooth muscle cells (VSMCs) and exosome-mediated proinflammatory effects on endothelial cells and macrophages. Loss of the insulin-like growth factor receptor (IGFR) in VSMCs can unmask the insulin receptor (IR) and increase insulin signaling. We have demonstrated that the loss of IGFR, coupled with physiological insulin stimulation, promotes an increased expression of miR-221/-222 in murine VSMCs. Respectively, miR-221/222 content in VSMC-derived exosomes increases and p27Kip1 mRNA expression decreases in VSMCs. We asked whether the effect of loss of IGFR in human coronary artery smooth muscle cells (HCASMCs) would also lead to an increase in miR-221/-222 content of VSMC-derived exosomes. Transfection with a CRISPR-cas9 plasmid targeting IGFR resulted in a 50% decrease in IGFR mRNA in HCASMCs, when compared to transfection with negative control CRISPR plasmids. Droplet digital PCR was used to measure expression of miR-221 and miR-222 in the exosomes derived from both sets of HCASMCs. There was no change in the miR-221/222 content of exosomes derived from HCASMCs transfected with the negative control CRISPR following stimulation with 1nM insulin (7.27± 4.75 vs. 11.33 ± 1.09 copies of miR-221 and 6.43 ± 0.43 vs. 4.68 ± 0.02 copies of miR-222). In contrast, there was a 2 to 3-fold increase in miR-221/222 content in exosomes that were derived from HCASMCs with IGFR knockdown following stimulation with 1nM insulin (14.96 ± 0.3 vs. 35.66 ± 3.08 copies of miR-221 and 9.12 ± 1.19 vs.15.44 ± 5.36 copies of miR-222). We conclude that loss of IGFR coupled with physiological insulin stimulation increases the miR-221/222 content of exosomes of HCASMCs, recapitulating the effects of IGFR loss seen in murine VSMCs as well as the effects of diabetes on VSMCs. This model system will allow additional studies connecting the loss of IGFR to the cardiovascular complications of diabetes. Tulane University School of Medicine, Biomedical Sciences Program. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Disrupted Insulin Signaling Due to an Acute Immune Response in Swine

Insulin is an anabolic hormone involved in glucose uptake and synthesis of fats, proteins, and glycogen. Altered insulin signaling can occur due to metabolic state, pathogen exposure, and autoimmune disorders. Lipopolysaccharide (LPS), an endotoxin secreted produced by gram-negative bacteria, can induce a severe, systemic immune response. In pigs, chronic LPS exposure has induced insulin resistance. However, the effects of acute exposure to LPS on insulin signaling and resistance has not been elucidated. Crossbred nursery pigs (58, 12.1 kg ± 0.23kg BW) were randomly assigned into two experimental subsets, where 10 animals were designated for repeated blood sampling and 48 animals underwent timed euthanasia for tissue collection. For repeated blood sampling, jugular catheters were placed under anesthesia and the animals were given 48 hours to recover before being randomly assigned to treatments. These treatments were an intraperitoneal injection of either 15μg/kg BW LPS or an equal volume of 0.9% Saline (n=5 pigs/treatment). Blood was collected for 48 hours followed by euthanasia. The other 48 pigs were randomly assigned to the same treatments, and then randomly assigned to euthanasia timepoints of 0, 3, 6, 12, 24 or 48 hours post injection for tissue collection. Among the catheterized pigs, two hours post LPS challenge there was a decrease in serum insulin concentration (p<0.05) and mild hyperglycemia (p<0.05) post challenge. At 12 and 24 hours post LPS challenge there was a decrease in insulin (p<0.05) and a trend hyperglycemia was also apparent at 24 hours (p=0.063). In liver tissue, insulin related genes exhibited alterations post LPS injection. Phosphoinositide 3-kinase ( pi3k) and insulin receptor substrate 1 ( irs1) expression were decreased at 3 and 6 hours (p<0.05) and protein kinase b ( akt) expression were decreased at 3 hours (p<0.05) post challenge. The expression of insulin inhibitor growth factor receptor bound protein 10 ( grb10) was decreased at 6, 12, and 24 hours after challenge (p<0.05). Fructose-1-6-bisphosphatase ( f16bp) expression was reduced at 3, 6, and 12 hours (p<0.05) in the liver while phosphoenolpyruvate carboxykinase ( pepck) expression was decreased at 3 and 6 hours (p<0.01) post challenge. Other metabolic genes were decreased at 3, 6, and 12 hours post LPS challenge, including fatty acid synthase ( fas) (p<0.05), carbohydrate response element binding protein ( chrebp) (p<0.05), and acetyl CoA carboxylase ( acc)(p<0.05). Protein abundance of Akt 3 hours after LPS injection was decreased in the liver (p<0.05). In skeletal muscle 6 hours post LPS injection, insulin receptor ( insr), insulin-like growth factor receptor ( igfr) and fas were all increased (p<0.05) These results indicate disrupted insulin signaling at various levels after an acute immune response. Research reported in this abstract was supported by Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD) of the National Institutes of Health under award number R01HD092304A. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Role of the Insulin-like Growth Factor System in Neurodegenerative Disease.

The insulin-like growth factor (IGF) system has paracrine and endocrine roles in the central nervous system. There is evidence that IGF signalling pathways have roles in the pathophysiology of neurodegenerative disease. This review focusses on Alzheimer's disease and Parkinson's disease, the two most common neurodegenerative disorders that are increasing in prevalence globally in relation to the aging population and the increasing prevalence of obesity and type 2 diabetes. Rodent models used in the study of the molecular pathways involved in neurodegeneration are described. However, currently, no animal model fully replicates these diseases. Mice with triple mutations in APP, PSEN and MAPT show promise as models for the testing of novel Alzheimer's therapies. While a causal relationship is not proven, the fact that age, obesity and T2D are risk factors in both strengthens the case for the involvement of the IGF system in these disorders. The IGF system is an attractive target for new approaches to management; however, there are gaps in our understanding that first need to be addressed. These include a focus beyond IGF-I on other members of the IGF system, including IGF-II, IGF-binding proteins and the type 2 IGF receptor.

Insulin Signaling Differentially Regulates the Trafficking of Insulin and Amyloid Beta Peptides at the Blood-Brain Barrier.

The blood-brain barrier (BBB) is instrumental in clearing toxic metabolites from the brain, such as amyloid-β (Aβ) peptides, and in delivering essential nutrients to the brain, like insulin. In Alzheimer's disease (AD) brain, increased Aβ levels are paralleled by decreased insulin levels, which are accompanied by insulin signaling deficits at the BBB. Thus, we investigated the impact of insulin-like growth factor and insulin receptor (IGF1R and IR) signaling on Aβ and insulin trafficking at the BBB. Following intravenous infusion of an IGF1R/IR kinase inhibitor (AG1024) in wild-type mice, the BBB trafficking of 125I radiolabeled Aβ peptides and insulin was assessed by dynamic SPECT/CT imaging. The brain efflux of [125I]iodo-Aβ42 decreased upon AG1024 treatment. Additionally, the brain influx of [125I]iodoinsulin, [125I]iodo-Aβ42, [125I]iodo-Aβ40, and [125I]iodo-BSA (BBB integrity marker) was decreased, increased, unchanged, and unchanged, respectively, upon AG1024 treatment. Subsequent mechanistic studies were performed using an in vitro BBB cell model. The cell uptake of [125I]iodoinsulin, [125I]iodo-Aβ42, and [125I]iodo-Aβ40 was decreased, increased, and unchanged, respectively, upon AG1024 treatment. Further, AG1024 reduced the phosphorylation of insulin signaling kinases (Akt and Erk) and the membrane expression of Aβ and insulin trafficking receptors (LRP-1 and IR-β). These findings reveal that insulin signaling differentially regulates the BBB trafficking of Aβ peptides and insulin. Moreover, deficits in IGF1R and IR signaling, as observed in the brains of type II diabetes and AD patients, are expected to increase Aβ accumulation while decreasing insulin delivery to the brain, which has been linked to the progression of cognitive decline in AD.

Exploring Emerging Therapeutic Targets and Opportunities in Neuroendocrine Tumors: Updates on Receptor Tyrosine Kinases

Neuroendocrine tumors (NETs) represent a diverse group of neoplasms originating from neuroendocrine cells, presenting varied clinical behaviors and posing significant challenges in management. This review explores the emerging roles of receptor tyrosine kinases (RTKs) in the pathogenesis and progression of NETs, including vascular endothelial growth factor receptors (VEGFRs), insulin-like growth factor receptors (IGF-1R), RET, epidermal growth factor receptor (EGFR), and ALK. The dysregulation of RTK signaling pathways contributes to key cellular processes such as proliferation, survival, and invasion in NETs. We discuss the potential of targeting RTKs as therapeutic strategies in NETs, with a focus on recent developments in RET inhibitors and the therapeutic implications of RTK alterations.

Sensitive and label-free SPR biosensing platforms for high-throughput screening of plasma membrane receptors interactions with insulin-like targets of hypoglycaemic activity

Progress in medical sciences aims for tailored therapy of civilization diseases like diabetes. Preclinical screening of new medicines superior to insulin should include the verification of their affinity to the membrane receptors naturally stimulated by this hormone: insulin receptor isoforms A and B and insulin-like growth factor receptor. Considering that the affinity constants obtained using different experimental conditions are incomparable, it is essential to develop a robust and reliable method to analyze these interactions. The versatile SPR platform developed in this study enables the evaluation of the bioactivity of hypoglycaemic molecules. Thanks to the comprehensive characterization of miscellaneous aspects of the analytical platform, including the design of the SPR biosensor receptor layer, ensuring interaction specificity, as well as the quality control of the standards used (human insulin, HI; long-acting insulin analog: glargine, Gla), the feasibility of the method of equilibrium and kinetic constants determination for insulin-like targets was confirmed. SPR assays constructed in the direct format using IR-A, IR-B, and IGF1-R receptor proteins show high sensitivities and low detection limits towards insulin and glargine detection in the range of 18.3–53.3 nM with no signs of mass transport limitations. The improved analytical performance and stability of SPR biosensors favor the acquisition of good-quality kinetic data, while preservation of receptors activity after binding to long-chain carboxymethyldextran, combined with spontaneous regeneration, results in stability and long shelf life of the biosensor, which makes it useful for label-free insulin analogs biosensing and thus extensive screening in diabetic drugs discovery.

Expression of IGF-1R in oral submucous fibrosis and oral squamous cell carcinoma – An RT-PCR study

ObjectivesWith the rising number of cases of oral submucous fibrosis (OSMF) undergoing malignant transformation into oral squamous cell carcinoma (OSCC), it is needed to detect the changes at the earliest. Several molecular markers have been used for this purpose, and insulin-like growth factor receptor 1 (IGF-1R) is one of the markers in vogue for several human malignancies. Thus, we compared the expression of IGF-1R mRNA in normal oral mucosa (NOM), OSMF, and OSCC. Materials and methodsThirty biopsy tissue samples for each of the three groups, NOM, OSMF, and OSCC, were taken and analyzed histopathologically and then subjected to RT-PCR for evaluation of the expression of IGF-1R mRNA in each of them. ResultsThere was an upregulation of IGF-1R mRNA in OSMF tissue samples as compared to NOM, but a downregulation as compared to OSCC. There was a 3.24-fold upregulation of IGF-1R mRNA expression in OSMF as compared to NOM and a 1.31-fold downregulation as compared to OSCC. Likewise, there was a 4.2-fold upregulation of IGF-1R mRNA expression in OSCC as compared to NOM and 1.31-fold upregulation as compared to OSMF. Moreover, the expression was more in OSMF patients with interincisal opening (IIO) < 27 mm as compared to those with IIO >27 mm and also was found to increase with the grade of OSCC. ConclusionThe study reflected a potential role of IGF-1R in the pathogenesis of OSMF and OSCC, thus implying its possible exploitation as a diagnostic and prognostic marker and also as a therapeutic target in future.

Abstract 7381: Mathematical modeling and validation of mechanistic target of rapamycin and N-myristoyltransferase signaling pathways in breast cancer

Abstract Hormone receptor-positive (HR+) breast cancer (BC) makes up approximately 65% of all breast cancers diagnosed. The prognosis for early-stage disease is excellent with mainstay endocrine therapy (ET). Despite the effectiveness of standard ET, as many as 41% of HR+ early-stage BC diagnosed women will experience distant recurrence. The resistance to endocrine therapy and recurrence is partly attributed to the activation of the insulin pathway and the independence of HR+ BC cells on the ER pathway for their growth. Earlier, we demonstrated the crosstalk between insulin/mTOR and ER pathways. N-myristoyltransferase (NMT) exists in humans in two paralogues (NMT1 and NMT2) that catalyze myristoylation reaction. Recent studies from our laboratory demonstrated that NMTs are downstream targets of insulin and ER pathways. In this study, we have designed mathematical models using differential equations to study the activation of the insulin pathway and its effect on NMT. The mathematical modeling incorporated the partition of cellular organelles and the sequential flow of information with cascades of equations representing signaling reactions. The activated mathematical model was designed by activating the insulin receptor (IR) or insulin-like growth factor receptor (IGF1R) and compared with the control model. The mathematical models were validated by wet lab experiments. The HR+ BC cells (MCF7) were treated with insulin or IGF1 for short term and long term. The expression patterns of NMT1, NMT2, and mTOR were determined by cell fractionation and western blot analysis. The results revealed the correlation between the differential expression patterns of NMTs and the proliferation of MCF7 cells when the insulin pathway was activated by insulin or IGF. The mathematical modeling was validated by simulations and data fittings. The results demonstrated that differential equation-based mathematical modeling could predict the NMT-related oncogenic changes in HR+ BC cells. Citation Format: Abinash Meher, Shailly Varma Shrivastav, Anouska Agarwal, Sheen Dube, Stephanie Portet, Anuraag Shrivastav. Mathematical modeling and validation of mechanistic target of rapamycin and N-myristoyltransferase signaling pathways in 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 7381.

Abstract 1918: LX-101, a novel, clinical stage, payload-bearing targeted therapy directed to the insulin-like growth factor receptor (IGF-1R), demonstrates potent preclinical anti-tumor activity against multiple cancer types with well-established ties to the IGF-1/IGF-1R pathway

Abstract Objective: LX-101 is a next-generation, targeted therapy directed to the insulin-like growth factor 1 receptor (IGF-1R). LX-101 consists of a proprietary IGF-1 variant coupled to a cytotoxic methotrexate payload. LX-101 was previously evaluated in Phase 1 trials of adult patients with advanced, pretreated cancers, where it was well-tolerated and demonstrated single agent activity. Neither a dose limiting toxicity, nor a maximum tolerated dose was reached, leaving potential room for additional dose escalation and schedule optimization. Multiple aggressive cancers of unmet need have genetic alterations affecting the IGF-1R pathway and/or high IGF-1R expression that correlates with poor outcomes, including certain cancers of the breast, head and neck, Ewing’s sarcoma, osteosarcoma, and others. Prior attempts at inhibiting IGF-1R with non-payload bearing naked monoclonal antibodies or small molecules produced a range of clinical outcomes including some partial and complete responses. None of these agents, however, were ultimately approved, potentially due to suboptimal potency that allowed for escape mechanisms, including redundant signaling pathways, and the lack of enrichment for select tumor types with strong ties to the IGF-1/IGF-1R pathway. Herein, we investigated the anti-tumor activity of the payload-bearing agent LX-101 against IGF-1R-involved cancer cell lines. Methods: Cell lines were incubated with LX-101 (~1.6 - 2500nM). Cell viability was assessed by CellTiter-Glo after 4 days. IC50s were calculated using GraphPad PRISM software. Results: LX-101 displayed potency against head and neck cancer (FaDu, IC50 = 9 nM), triple negative breast cancer (BT-20, IC50 = 17 nM), Ewing’s sarcoma, including EWSR1-FLI1 gene fusion-positive cell lines RD-ES (IC50 = 10 nM), A-673 (IC50 = 14 nM), and SK-ES-1 (IC50 = 29 nM) and EWSR1-ERG gene fusion-positive cell line CADO-ES1 (IC50 = 14 nM). LX-101 was also potent against PAX3-FOXO1 gene fusion positive alveolar rhabdomyosarcoma (SJCRH30, IC50 = 23 nM), osteosarcoma (143B, IC50 = 6 nM; HOS, IC50 = 7 nM; U2OS, IC50 = 32 nM), and neuroblastoma (SK-N-AS, IC50 = 16 nM; IMR-32, IC50 = 20 nM; SH-SY5Y, IC50 = 30 nM). Conclusion: These results demonstrate that LX-101 has potent preclinical anti-tumor activity against multiple cancer cell lines with well-established ties to the IGF-1/IGF-1R pathway, including with different genetic and epigenetic alterations. These data support further clinical development of LX-101 in IGF-1R-involved cancers. New clinical trials are planned. Citation Format: Matt Hoberman, Arkadiusz Z. Dudek. LX-101, a novel, clinical stage, payload-bearing targeted therapy directed to the insulin-like growth factor receptor (IGF-1R), demonstrates potent preclinical anti-tumor activity against multiple cancer types with well-established ties to the IGF-1/IGF-1R pathway [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 1918.

Abstract 3635: Insulin-like growth factor receptor predicts poor prognosis in early-stage non-small cell lung cancer

Abstract Introduction: Insulin like growth factor receptor (IGF1R) is involved in the proliferation and metastasis of various cancers. However, the clinical significance of IGF1R in non-small cell lung cancer (NSCLC) remains to be unclear. In this study, we retrospectively evaluated the correlation between IGF1R expression and clinicopathological features of NSCLC. Method: A total of 782 specimens of NSCLC patients who underwent surgical resection of primary lung cancer between 2010 and 2019 at Osaka Metropolitan University Hospital was enrolled in this study. Immunohistochemical staining of IGF1R were performed, and the correlation between IGF1R expression and clinicopathological features of NSCLC, especially in recurrence free survival (RFS) and overall survival (OS), was evaluated. We also evaluated an association between IGF1R and programmed death ligand 1 (PD-L1) expression. Results: IGF1R expression was positive in 279 (35.8%) patients. IGF1R-positive group had significantly longer smoking histories (median smoking index, 1,000 vs 600, p &amp;lt;0.01) and a higher proportion of squamous cell carcinomas (35.1% vs 14.1 %, p &amp;lt;0.01). IGF1R-positive group also significantly expressed PD-L1 (24.4% vs 6.4%, p&amp;lt;0.01). IGF1R-positive group had significantly worse RFS (10-year recurrence-free rate; 42.7% vs 53.7%, p &amp;lt;0.01) and OS (10-year survival rate; 54.4% vs 67.3%, p &amp;lt;0.01). RFS and OS were significantly worse in the IGF1R-positive NSCLC patients at stage 0 and stage I (10-year recurrence-free rate; 49.0% vs 62.9%, p &amp;lt;0.01, 10-year survival rate; 57.4% vs 74.2%, p&amp;lt;0.01), but not in stage II (10-year recurrence-free rate; 52.0% vs 43.8%, p=0.68, 10-year survival rate; 63.4% vs 47.5%, p=0.95) and III (10-year recurrence-free rate; 20.7% vs 20.8%, p=0.77, 10-year survival rate; 38.3% vs 54.6%, p=0.18). IGF1R expression was associated with poorer RFS and OS in early-stage NSCLC. Conclusion: IGF1R is a predictor of poor prognosis in resected early-stage NSCLC. Citation Format: Hiroaki nagamine, Masakazu Yashiro, Megumi Mizutani, Akira Sugimoto, Yoshiya Matsumoto, Yoko Tani, Kenji Sawa, Kazuhiro Yamada, Hiroyasu Kaneda, Tetsuya Watanabe, Kazuhisa Asai, Satoshi Suzuki, Tomoya Kawaguchi. Insulin-like growth factor receptor predicts poor prognosis in early-stage non-small cell lung 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 3635.