IGF-1R Research Articles

IGFBP7 Fuels the Glycolytic Metabolism in B-Cell Precursor Acute Lymphoblastic Leukemia by Sustaining Activation of the IGF1R-Akt-GLUT1 Axis.

Increased glycolytic metabolism plays an important role in B-cell precursor Acute Lymphoblastic Leukemia (BCP-ALL). We previously showed that IGFBP7 exerts mitogenic and prosuvival effects in ALL by promoting IGF1 receptor (IGF1R) permanence on the cell surface, thus prolonging Akt activation upon IGFs/insulin stimulation. Here, we show that sustained activation of the IGF1R-PI3K-Akt axis concurs with GLUT1 upregulation, which enhances energy metabolism and increases glycolytic metabolism in BCP-ALL. IGFBP7 neutralization with a monoclonal antibody or the pharmacological inhibition of the PI3K-Akt pathway was shown to abrogate this effect, restoring the physiological levels of GLUT1 on the cell surface. The metabolic effect described here may offer an additional mechanistic explanation for the strong negative impact seen in ALL cells in vitro and in vivo after the knockdown or antibody neutralization of IGFBP7, while reinforcing the notion that it is a valid target for future therapeutic interventions.

Effect of microRNA-21 blockade in human triple negative breast cancer allografts on progression and immune checkpoint proteins.

e13097 Background: Triple negative breast cancer (TNBC) is an orphan disease that attacks > 46,000 US women every year. TNBC recurs after standard-of-care surgery, chemotherapy and radiation, killing half its victims within 4 years. Poly(ADP-ribose) polymerase (PARP) inhibitors, topoisomerase inhibitors, immune checkpoint inhibitors, and antibody-drug conjugates extend the survival of a fraction of TNBC patients for a few months. Thus, TNBC shows a critical need for molecularly-targeted therapy. Most TNBC cells show high microRNA 21 (miR-21), identical in humans and mice, which decreases tumor suppressor proteins that keep cell growth in check. Hypothesis: Short anti-miR-21 RNA analogs conjugated to a receptor ligand will direct TNBC cell uptake and slow the growth of TNBC orthotopic allografts with immune activation and minimal toxicity. Methods: We designed an anti-miR-21 RNA analog using aminomethyl bridged nucleic acid (BNA), exhibiting low toxicity, and serum stability. We lipofected a concentration ramp of the anti-miR-21 RNA analog into human TNBC cell lines (MDA-MB-231, MDA-MB-157, MDA-MB-436, MDA-MB-468, BT-20, BT-549, HCC1806, HCC1937, HCC1806) representing a spectrum of TNBC subtypes, then measured proliferation and biochemical markers. We also conjugated a peptide analog for endocytosis by the insulin-like growth factor 1 receptor (IGF1R), overexpressed in most TNBC lesions. The peptide ligand for IGF1R provides a unique strategy for delivering the anti-miR-21 RNA analog preferentially into TNBC cells. We administered 5 mg/kg of the anti-miR-21 RNA-peptide analog in sterile saline intraperitoneally twice a week for 14 days into immunocompetent female Balb/c mice bearing syngeneic EMT6 TNBC tumors in their mammary fat pads. Results: The anti-miR-21 RNA analog slowed proliferation, increased apoptosis, elevated tumor suppressor proteins, and suppressed immune checkpoint gene expression in multiple human TNBC lines. IC50 for inhibiting cell proliferation correlated with miR-21 copies/cell in 7 TNBC cell lines, but not in the non-tumorigenic breast epithelial cell line MCF-10A. The anti-miR-21 RNA-peptide analog stopped orthotopic TNBC allograft growth in syngeneic immunocompetent female Balb/c mice during 14 days of therapy, with apparent safety. Conclusions: This strategy optimizes cancer cell-specific delivery to block proliferation and immune checkpoints. The results support further preclinical proof-of-concept studies to enable an eIND submission for the anti-miR-21 RNA-peptide analog.

Promotion of longitudinal bone growth by the intake of oat and green onion root water extracts in weaning rats through stimulating growth hormone secretion and elevating gut microbiota related to nervous system-related pathway

We determined whether oral oat and green onion water extracts (GOO) supplementation could stimulate longitudinal bone growth in weaning rats. Fistuloside A, B, and C in the green onions and 26-desglucoavenacoside A and B and avenacoside A in the oats lowered the binding energy of growth differentiation factor-5 (GDF5) and insulin-like growth factor-1 receptor (IGF1R). After a 4-week treatment, serum growth hormone (GH) and osteoprotegerin concentrations in the High-GOO group (500 mg/kg body weight) were similar to those of the Positive-control. The femur and tibia lengths promoting the proliferative and hypertrophic zones of the growth plate in the High-GOO were also similar to Positive-control. Along with increasing serum propionate and butyrate concentrations, cecal bacteria in the High-GOO were higher in virus infection, steroid and sesquiterpenoid biosynthesis, and nervous system-related pathways than the Control in the metagenome function. It suggested that gut bacteria potentially enhanced bone growth by improving immunity and neurological activity. In conclusion, GOO increased leg length by enhancing the proliferation of the growth plate as much as GH treatment by preventing gut dysbiosis.

Alcohol as a Modifiable Risk Factor for Alzheimer's Disease-Evidence from Experimental Studies.

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive impairment and memory loss. Epidemiological evidence suggests that heavy alcohol consumption aggravates AD pathology, whereas low alcohol intake may be protective. However, these observations have been inconsistent, and because of methodological discrepancies, the findings remain controversial. Alcohol-feeding studies in AD mice support the notion that high alcohol intake promotes AD, while also hinting that low alcohol doses may be protective against AD. Chronic alcohol feeding to AD mice that delivers alcohol doses sufficient to cause liver injury largely promotes and accelerates AD pathology. The mechanisms by which alcohol can modulate cerebral AD pathology include Toll-like receptors, protein kinase-B (Akt)/mammalian target of rapamycin (mTOR) pathway, cyclic adenosine monophosphate (cAMP) response element-binding protein phosphorylation pathway, glycogen synthase kinase 3-β, cyclin-dependent kinase-5, insulin-like growth factor type-1 receptor, modulation of β-amyloid (Aβ) synthesis and clearance, microglial mediated, and brain endothelial alterations. Besides these brain-centric pathways, alcohol-mediated liver injury may significantly affect brain Aβ levels through alterations in the peripheral-to-central Aβ homeostasis. This article reviews published experimental studies (cell culture and AD rodent models) to summarize the scientific evidence and probable mechanisms (both cerebral and hepatic) by which alcohol promotes or protects against AD progression.

Enzalutamide and olaparib synergistically suppress castration-resistant prostate cancer progression by promoting apoptosis through inhibiting nonhomologous end joining pathway.

Recent studies revealed the relationship among homologous recombination repair (HRR), androgen receptor (AR), and poly(adenosine diphosphate-ribose) polymerase (PARP); however, the synergy between anti-androgen enzalutamide (ENZ) and PARP inhibitor olaparib (OLA) remains unclear. Here, we showed that the synergistic effect of ENZ and OLA significantly reduced proliferation and induced apoptosis in AR-positive prostate cancer cell lines. Next-generation sequencing followed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed the significant effects of ENZ plus OLA on nonhomologous end joining (NHEJ) and apoptosis pathways. ENZ combined with OLA synergistically inhibited the NHEJ pathway by repressing DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and X-ray repair cross complementing 4 (XRCC4). Moreover, our data showed that ENZ could enhance the response of prostate cancer cells to the combination therapy by reversing the anti-apoptotic effect of OLA through the downregulation of anti-apoptotic gene insulin-like growth factor 1 receptor (IGF1R) and the upregulation of pro-apoptotic gene death-associated protein kinase 1 (DAPK1). Collectively, our results suggested that ENZ combined with OLA can promote prostate cancer cell apoptosis by multiple pathways other than inducing HRR defects, providing evidence for the combined use of ENZ and OLA in prostate cancer regardless of HRR gene mutation status.

Extended-Synaptotagmin 1 Enhances Liver Cancer Progression Mediated by the Unconventional Secretion of Cytosolic Proteins.

Extended-synaptotagmin 1 (E-Syt1) is an endoplasmic reticulum membrane protein that is involved in cellular lipid transport. Our previous study identified E-Syt1 as a key factor for the unconventional protein secretion of cytoplasmic proteins in liver cancer, such as protein kinase C delta (PKCδ); however, it is unclear whether E-Syt1 is involved in tumorigenesis. Here, we showed that E-Syt1 contributes to the tumorigenic potential of liver cancer cells. E-Syt1 depletion significantly suppressed the proliferation of liver cancer cell lines. Database analysis revealed that E-Syt1 expression is a prognostic factor for hepatocellular carcinoma (HCC). Immunoblot analysis and cell-based extracellular HiBiT assays showed that E-Syt1 was required for the unconventional secretion of PKCδ in liver cancer cells. Furthermore, deficiency of E-Syt1 suppressed the activation of insulin-like growth factor 1 receptor (IGF1R) and extracellular-signal-related kinase 1/2 (Erk1/2), both of which are signaling pathways mediated by extracellular PKCδ. Three-dimensional sphere formation and xenograft model analysis revealed that E-Syt1 knockout significantly decreased tumorigenesis in liver cancer cells. These results provide evidence that E-Syt1 is critical for oncogenesis and is a therapeutic target for liver cancer.

Glucolipotoxic Stress-Induced Mig6 Desensitizes EGFR Signaling and Promotes Pancreatic Beta Cell Death.

A loss of functional beta cell mass is a final etiological event in the development of frank type 2 diabetes (T2D). To preserve or expand beta cells and therefore treat/prevent T2D, growth factors have been considered therapeutically but have largely failed to achieve robust clinical success. The molecular mechanisms preventing the activation of mitogenic signaling pathways from maintaining functional beta cell mass during the development of T2D remain unknown. We speculated that endogenous negative effectors of mitogenic signaling cascades impede beta cell survival/expansion. Thus, we tested the hypothesis that a stress-inducible epidermal growth factor receptor (EGFR) inhibitor, mitogen-inducible gene 6 (Mig6), regulates beta cell fate in a T2D milieu. To this end, we determined that: (1) glucolipotoxicity (GLT) induces Mig6, thereby blunting EGFR signaling cascades, and (2) Mig6 mediates molecular events regulating beta cell survival/death. We discovered that GLT impairs EGFR activation, and Mig6 is elevated in human islets from T2D donors as well as GLT-treated rodent islets and 832/13 INS-1 beta cells. Mig6 is essential for GLT-induced EGFR desensitization, as Mig6 suppression rescued the GLT-impaired EGFR and ERK1/2 activation. Further, Mig6 mediated EGFR but not insulin-like growth factor-1 receptor nor hepatocyte growth factor receptor activity in beta cells. Finally, we identified that elevated Mig6 augmented beta cell apoptosis, as Mig6 suppression reduced apoptosis during GLT. In conclusion, we established that T2D and GLT induce Mig6 in beta cells; the elevated Mig6 desensitizes EGFR signaling and induces beta cell death, suggesting Mig6 could be a novel therapeutic target for T2D.

Treatment Response With VRDN-001, a Full Antagonist Antibody to IGF-1 Receptor, in Thyroid Eye Disease (TED): Phase 1/2 Clinical Study

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Treatment with linsitinib, an IGF-1 receptor inhibitor, attenuates disease development and progression in an experimental model of Graves’ Orbitopathy

Abstract Study objective: The activity of linsitinib, a small molecule inhibitor of the insulin-like growth factor 1 receptor (IGF-1R), was assessed in a mouse model of Graves’ orbitopathy (GO). GO is the most common extra-thyroidal manifestation of Graves’ disease (GD), which is caused by autoantibodies against the thyroid stimulating hormone receptor (TSHR). Methods: GD was induced in mice by immunization with a human TSHR A-subunit encoding plasmid. Linsitinib was administered orally for four weeks either in parallel to or after disease induction. Endocrine orbitopathy and inflammation were determined by histology and MRI. Results: Immunization with the TSHR A-subunit induced hyperthyroidism, as well as CD3+ T-cell infiltration and macrophage infiltration into orbital muscle/adipose tissue. Linsitinib reduced these effects by up to 80% whether given prophylactically or after disease induction. In addition, linsitinib reduced the formation of brown adipose tissue in the orbit and displayed an additional effect on the immune system. An MRI using F19 imaging confirmed marked orbital inflammation, significant muscle edema and formation of brown fat in experimental GO, events that were abrogated upon application of linsitinib. Linsitinib’s pharmacologic effects were observed at a dose that did not impact the concentration of plasma glucose. Conclusion: Linsitinib improved GO-related endpoints in a TSHR autoantibody dependent mouse model of Graves’ disease. Both prophylactic and therapeutic intervention with linsitinib improved clinically relevant endpoints in the orbita and thyroid gland. Our results are consistent with the therapeutic hypothesis being evaluated in an ongoing Phase 2b clinical study (NCT05276063). This work was funded by Sling Therapeutics, Inc.

Insulin signaling is critical for sinoatrial node maintenance and function

Insulin and insulin-like growth factor 1 (IGF-1) signaling regulate cellular growth and glucose metabolism in the myocardium. However, their physiological role in the cells of the cardiac conduction system has never been explored. Therefore, we sought to determine the spatiotemporal function of insulin/IGF-1 receptors in the sinoatrial node (SAN). We generated cardiac conduction cell-specific inducible IGF-1 receptor (IGF-1R) knockout (KO) (CSIGF1RKO), insulin receptor (IR) KO (CSIRKO), and IR/IGF-1R double-KO (CSDIRKO) mice and evaluated their phenotypes. Telemetric electrocardiography revealed regular sinus rhythm in CSIGF1RKO mice, indicating that IGF-1R is dispensable for normal pacemaking. In contrast, CSIRKO and CSDIRKO mice exhibited profound sinus bradycardia. CSDIRKO mice showed typical sinus node dysfunction characterized by junctional rhythm and sinus pauses on electrocardiography. Interestingly, the lack of an insulin receptor in the SAN cells of CSIRKO and CSDIRKO mice caused sinus nodal fibrosis. Mechanistically, hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4) protein expression significantly decreased in the CSIRKO and CSDIRKO mice relative to the controls. A patch-clamp study of the SAN cells of CSIRKO mice revealed a significant decrease in the funny current, which is responsible for spontaneous diastolic depolarization in the SAN. This result suggested that insulin receptor loss reduces the heart rate via downregulation of the HCN4 channel. Additionally, HCN1 expression was decreased in CSDIRKO mice, explaining their sinus node dysfunction. Our results reveal a previously unrecognized role of insulin/IGF-1 signaling in sinus node structural maintenance and pacemaker function.

Heat-killed Lacticaseibacillus paracasei GMNL-653 ameliorates human scalp health by regulating scalp microbiome

BackgroundThe equilibrium of the scalp microbiome is important for maintaining healthy scalp conditions, including sebum secretion, dandruff, and hair growth. Many different strategies to improve scalp health have been reported; however, the effect of postbiotics, such as heat-killed probiotics, on scalp health remains unclear. We examined the beneficial effects of heat-killed probiotics consisting of Lacticaseibacillus paracasei, GMNL-653, on scalp health.ResultsHeat-killed GMNL-653 could co-aggregate with scalp commensal fungi, Malassezia furfur, in vitro, and the GMNL-653-derived lipoteichoic acid inhibited the biofilm formation of M. furfur on Hs68 fibroblast cells. The mRNA of hair follicle growth factors, including insulin-like growth factor-1 receptor (IGF-1R), vascular endothelial growth factor, IGF-1, and keratinocyte growth factor was up-regulated in skin-related human cell lines Hs68 and HaCaT after treatment with heat-killed GMNL-653. For clinical observations, we recruited 22 volunteer participants to use the shampoo containing the heat-killed GMNL-653 for 5 months and subsequently measured their scalp conditions, including sebum secretion, dandruff formation, and hair growth. We applied polymerase chain reaction (PCR) to detect the scalp microbiota of M. restricta, M. globosa, Cutibacterium acnes, and Staphylococcus epidermidis. A decrease in dandruff and oil secretion and an increase in hair growth in the human scalp were observed after the use of heat-killed GMNL-653-containing shampoo. The increased abundance of M. globosa and the decreased abundance of M. restricta and C. acnes were also observed. We further found that accumulated L. paracasei abundance was positively correlated with M. globosa abundance and negatively correlated with C. acnes abundance. S. epidermidis and C. acnes abundance was negatively correlated with M. globosa abundance and positively correlated with M. restricta. Meanwhile, M. globosa and M. restricta abundances were negatively associated with each other. C. acnes and S. epidermidis abundances were statistically positively correlated with sebum secretion and dandruff, respectively, in our shampoo clinical trial.ConclusionOur study provides a new strategy for human scalp health care using the heat-killed probiotics GMNL-653-containing shampoo. The mechanism may be correlated with the microbiota shift.

Anti-apoptotic and anti-fibrotic efficacy of exercise training in hypertensive hearts: A systematic review.

This review aims to summarize the antiapoptotic, pro-survival, and antifibrotic effects of exercise training in hypertensive hearts. Keyword searches were conducted in PubMed, Web of Science, and Scopus in May 2021. Research published in English on the effects of exercise training on the apoptosis, survival, and fibrosis pathways in hypertension was included. The CAMARADES checklist was used to determine the quality of the studies. Two reviewers independently implemented predesigned protocols for the search and selection of studies, the assessment of study quality, and the evaluation of the strength of evidence. Eleven studies were included after selection. The duration of the exercise training ranged from 5 to 27 weeks. Nine studies showed that exercise training improved cardiac survival rates by increasing IGF-1, IGF-1 receptor, p-PI3K, Bcl-2, HSP 72, and p-Akt. Furthermore, 10 studies showed that exercise training reduced apoptotic pathways by downregulating Bid, t-Bid, Bad, Bak, Bax, TNF, and FADD. Finally, two studies reported the modification and subsequent improvement of physiological characteristics of fibrosis and decreased MAPK p38 and PTEN levels by exercise training in the left ventricle of the heart. The findings of the review showed that exercise training could improve cardiac survival rates and attenuate cardiac apoptotic and fibrotic pathways in hypertension, suggesting that exercise training could act as a therapeutic approach to prevent hypertension-induced cardiac apoptosis and fibrosis. https://www.crd.york.ac.uk, identifier: CRD42021254118.

Phase 1 Safety and Pharmacodynamic Results of VRDN-001, a Full Antagonist Antibody to the Insulin-Like Growth Factor-1 Receptor (IGF-1R) in Development for Thyroid Eye Disease (TED) (P3-9.007)

<h3>Objective:</h3> Report the interim safety and pharmacodynamic (PD) results for healthy volunteers from a phase 1/2 clinical trial (NCT05176639) evaluating VRDN-001 intravenously administered at 3–20 mg/kg. <h3>Background:</h3> Clinical and preclinical studies have confirmed insulin-like growth factor-1 receptor (IGF-1R) antagonism can reduce the inflammation and proptosis that occur in Thyroid Eye Disease (TED). VRDN-001, a full antagonist antibody to the IGF-1R, is under development for the treatment of TED. <h3>Design/Methods:</h3> Adult healthy volunteers were randomized 3:1 to receive 2 intravenous infusions 3 weeks apart of either placebo or 3, 10, or 20 mg/kg VRDN-001. PD parameters (IGF-1 serum levels) and adverse events (AEs) were assessed up to 50 days. <h3>Results:</h3> Thirteen participants received VRDN-001 3 mg/kg (n=3), 10 mg/kg (n=3), 20 mg/kg (n=4), or placebo (n=3). Mean age was 49 years (range: 25–73) and 5 were female. All VRDN-001 doses elicited rapid, sustained, and similar increases in IGF-1 serum levels, a biomarker for IGF-1R inhibition. Following the first infusion, IGF-1 increased within a day, reaching 3–5-fold above baseline by Day 8. Increases were sustained until the second infusion, and then further increased to 5–7-fold above baseline (&gt;500 ng/mL), and sustained through Day 50. No increases in serum IGF-1 occurred for placebo. Eleven of the 13 participants experienced 19 AEs (16 mild and 3 moderate). Transient hypotension (10 mg/kg group) and muscle spasm (placebo group) were the only AEs to be deemed treatment-related by the masked investigator. No treatment-related hyperglycemia or hearing impairment was observed. <h3>Conclusions:</h3> VRDN-001 administered to healthy volunteers at 3–20 mg/kg indicated maximal target engagement at all doses and was generally safe and well-tolerated, with no observed treatment-related hyperglycemia or hearing impairment. Results from the ongoing evaluation of VRDN-001 dosed at 3–20 mg/kg in TED patients will further inform potential treatment regimens. <b>Disclosure:</b> Dr. She has received personal compensation for serving as an employee of Viridian Therapeutics. Dr. She has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Dianthus Therapeutics. Dr. She has stock in Viridian Therapeutics. Dr. Katz has received personal compensation for serving as an employee of Viridian Therapeutics. Dr. Katz has received stock or an ownership interest from Viridian Therapeutics. Mrs. Summerfelt has received personal compensation for serving as an employee of Viridian Therapeutics. An immediate family member of Mrs. Summerfelt has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Viridian Therapeutics. Mrs. Summerfelt has stock in Viridian Therapeutics. Dr. Oshaughnessy has received personal compensation for serving as an employee of viridian therapeutics. Dr. Oshaughnessy has stock in viridian therapeutics. Mr. Dickinson has nothing to disclose. Dr. Foster has received personal compensation for serving as an employee of Viridian Therapeutics. Dr. Bedian has received personal compensation for serving as an employee of Viridian Therapeutics. Dr. Bedian has received personal compensation for serving as an employee of Dianthus Therapeutics. Dr. Bedian has stock in Viridian Therapeutics. Dr. Bedian has stock in Astria Therapeutics.

Feeding enhances fibronectin adherence of quiescent lymphocytes through non-canonical insulin signalling.

Nutritional availability during fasting and refeeding affects the temporal redistribution of lymphoid and myeloid immune cells among the circulating and tissue-resident pools. Conversely, nutritional imbalance and impaired glucose metabolism are associated with chronic inflammation, aberrant immunity and anomalous leukocyte trafficking. Despite being exposed to periodic alterations in blood insulin levels upon fasting and feeding, studies exploring the physiological effects of these hormonal changes on quiescent immune cell function and trafficking are scanty. Here, we report that oral glucose load in mice and healthy men enhances the adherence of circulating peripheral blood mononuclear cells (PBMCs) and lymphocytes to fibronectin. Adherence to fibronectin is also observed upon regular intake of breakfast following overnight fasting in healthy subjects. This glucose load-induced phenomenon is abrogated in streptozotocin-injected mice that lack insulin. Intra-vital microscopy in mice demonstrated that oral glucose feeding enhances the homing of PBMCs to injured blood vessels in vivo. Furthermore, employing flow cytometry, Western blotting and adhesion assays for PBMCs and Jurkat-T cells, we elucidate that insulin enhances fibronectin adherence of quiescent lymphocytes through non-canonical signalling involving insulin-like growth factor-1 receptor (IGF-1R) autophosphorylation, phospholipase C gamma-1 (PLCγ-1) Tyr783 phosphorylation and inside-out activation of β-integrins respectively. Our findings uncover the physiological relevance of post-prandial insulin spikes in regulating the adherence and trafficking of circulating quiescent T-cells through fibronectin-integrin interaction.

IGF-1 receptor inhibitor OSI-906 reduces growth in nestlings of a wild passerine

Young animals need to grow to a large body size fast to maximise their survival prospects until sexual maturity. However, body size varies substantially in wild populations, and neither the selection pressures maintaining this variation, nor the regulatory mechanisms are well understood. IGF-1 administration has been shown to accelerate growth, but this does not necessarily imply that natural variation in growth rate is IGF-1 dependent. To test the latter we administered OSI-906 to pied flycatcher Ficedula hypoleuca nestlings, which has an inhibitory effect on IGF-1 receptor activity. We performed the experiment in two breeding seasons to test the prediction that blocking the IGF-1 receptor downregulates growth. As predicted, OSI-906 treated nestlings had lower body mass and reached a smaller structural size than siblings receiving a vehicle only, with the mass difference being most profound at the age preceding the highest body mass growth rate. The IGF-1 receptor inhibition effect on growth varied with age and year of study, and we discuss possible explanations. The OSI-906 administration results indicate that natural variation in growth rate is regulated by IGF-1, and constitutes a novel tool to study causes and consequences of growth variation, but details of the underlying mechanism still need to be resolved.

Potent antitumor effects of the conditioned medium of bone marrow-derived mesenchymal stem cells via IGFBP-4.

Cell transfer therapy using mesenchymal stem cells (MSCs) has pronounced therapeutic potential, but concerns remain about immune rejection, emboli formation, and promotion of tumor progression. Because the mode of action of MSCs highly relies on their paracrine effects through secretion of bioactive molecules, cell-free therapy using the conditioned medium (CM) of MSCs is an attractive option. However, the effects of MSC-CM on tumor progression have not been fully elucidated. Herein, we addressed this issue and investigated the possible underlying molecular mechanisms. The CM of MSCs derived from human bone marrow greatly inhibited the in vitro growth of several human tumor cell lines and the in vivo growth of the SCCVII murine squamous cell carcinoma cell line with reduced neovascularization. Exosomes in the MSC-CM were only partially involved in the inhibitory effects. The CM contained a variety of cytokines including insulin-like growth factor binding proteins (IGFBPs). Among them, IGFBP-4 greatly inhibited the in vitro growth of these tumors and angiogenesis, and immunodepletion of IGFBP-4 from the CM significantly reversed these effects. Of note, the CM greatly reduced the phosphorylation of AKT, ERK, IGF-1 receptor beta, and p38 MAPK in a partly IGFBP4-dependent manner, possibly through its binding to IGF-1/2 and blocking the signaling. The CM depleted of IGFBP-4 also reversed the inhibitory effects on in vivo tumor growth and neovascularization. Thus, MSC-CM has potent inhibitory effects on tumor growth and neovascularization in an IGFBP4-dependent manner, suggesting that cell-free therapy using MSC-CM could be a safer promising alternative for even cancer patients.

The effect of insulin-like growth factor 1 receptor gene single nucleotide polymorphism on growth and milk production traits in two native Indian tropical goat breeds

Insulin like growth factor1(IGF-1) is an essential growth factor that mediates the growth-promoting functions of pituitary growth hormone. Insulin like growth factor 1 receptor (IGF1R) is a tyrosine kinase receptor that mediates the actions of IGF1. Therefore, IGF1R is a candidate gene for examining SNPs linked with growth and production traits. The objective of this study was to detect the c.546 + 179170A > T transversion in intron 2 of the gene encoding IGF1R in two goat breeds, Attappady Black and Malabari, and examine the association of this polymorphism with growth and milk production. For the identification of the SNP, the T-ARMS-PCR was utilized. All three genotypes were present in the two investigated breeds. The polymorphism was found to be significantly (p < 0.05) linked with growth traits. At birth, 3 and 6 months of age, Attappady goats with the AT genotype had significantly (p < 0.05) higher body weights than those with the AA and TT genotypes. Malabari goats with the AT genotype had significantly (p < 0.05) higher body weights at birth and at 3 months of age. The genotypes of the IGF1R gene had no effect on total or peak milk production. Therefore, this SNP could be used as a molecular marker in selection of meat-producing goat breeds. HIGHLIGHTS c.546 + 179170A > T IGF1R transversion was detected using T-ARMS-PCR in two indigenous goat breeds from Kerala. Attappady Black and Malabari goat breeds of Kerala possessed all the three genotypes In these breeds, there was a significant correlation between this SNP, c.546 + 179170A > T IGF1R, and body weight. In both the breeds, there was no association between this SNP and milk production traits.

AG1024, an IGF-1 receptor inhibitor, ameliorates renal injury in rats with diabetic nephropathy via the SOCS/JAK2/STAT pathway.

Insulin-like-growth factor-1 (IGF-1) is the ligand for insulin-like growth factor-1 receptor (IGF-1R), and the roles of IGF-1/IGF-1R in diabetic nephropathy (DN) are well-characterized previously. However, the biological functions of AG1024 (an IGF-1R inhibitor) in DN remain unknown. This study investigates the roles and related mechanisms of AG-1024 in DN. The experimental DN was established via intraperitoneal injection of streptozotocin, and STZ-induced diabetic rats were treated with AG1024 (20 mg/kg/day) for 8 weeks. The 24 h proteinuria, blood glucose level, serum creatinine, and blood urea nitrogen were measured for biochemical analyses. The increase in 24 h proteinuria, blood glucose level, serum creatinine, and blood urea of DN rats were conspicuously abated by AG1024. After biochemical analyses, the renal tissue specimens were collected, and as revealed by hematoxylin and eosin staining and Masson staining, AG-1024 mitigated typical renal damage and interstitial fibrosis in DN rats. Then, the anti-inflammatory effect of AG-1024 was assessed by western blotting and ELISA. Mechanistically, AG-1024 upregulated SOCS1 and SOCS3 expression and decreased phosphorylated JAK2, STAT1, and STAT3, as shown by western blotting. Collectively, AG-1024 (an IGF-1R inhibitor) ameliorates renal injury in experimental DN by attenuating renal inflammation and fibrosis via the SOCS/JAK2/STAT pathway.

Mechanism of myocardial fibrosis regulation by IGF-1R in atrial fibrillation through the PI3K/Akt/FoxO3a pathway.

Atrial structural remodeling takes on a critical significance to the occurrence and maintenance of atrial fibrillation (AF). As revealed by recent data, insulin-like growth factor-1 receptor (IGF-1R) plays a certain role in tissue fibrosis. In this study, the mechanism of IGF-1R in atrial structural remodeling was examined based on in vivo and in vitro experiments. First, cluster analysis of AF hub genes was conducted, and then the molecular mechanism was proposed by which IGF-1R regulates myocardial fibrosis via the PI3K/Akt/FoxO3a pathway. Subsequently, the mentioned mechanism was verified in human cardiac fibroblasts (HCFs) and rats transduced with IGF-1 overexpression type 9 adeno-associated viruses. The results indicated that IGF-1R activation up-regulated collagen Ⅰ protein expression and Akt phosphorylation in HCFs and rat atrium. The administration of LY294002 reversed the above phenomenon, improved the shortening of atrial effective refractory period, and reduced the increased incidence of AF and atrial fibrosis in rats. The transfection of FoxO3a siRNA reduced the anti-fibrotic effect of LY294002 in HCFs. The above data revealed that activation of IGF-1R takes on a vital significance to atrial structural remodeling by facilitating myocardial fibrosis and expediting the occurrence and maintenance of AF through the regulation of the PI3K/Akt/FoxO3a signaling pathway.

Abstract 5806: Kinase library screening identifies IGF-1R/PI3K/AKT axis as a crucial pathway for survival of intrahepatic cholangiocarcinoma cells with stemness characteristics

Abstract Intrahepatic cholangiocarcinoma (iCCA) is a subtype of biliary malignancy that arises along the peripheral bile duct epithelium. Given its limited and inefficacious treatment options, the mortality rate of iCCA remains high and thus a novel therapeutic strategy is urgently needed. The concept of cancer stem cells (CSCs) explains a subpopulation of cancer cells that possesses self-renewal and differentiation capacities. These CSCs become the culprit for cancer metastasis, cancer recurrence and chemotherapeutic resistance, making them promising targets for cancer treatment. The propose of this study is to identify the signaling pathways crucial for the survival of iCCA with stemness characteristics. Gene expression analysis on a dataset of Thai iCCA patients (n=91) showed that iCCA tumors are enriched in the Adult Stem Cell (ASC) signature which are the shared characteristics among the epithelial-derived cancer with stemness characteristics. Although iCCA cells exhibit some degree of enrichment in stem cells markers when compared with cholangiocyte cells, further upregulation of stem cell-related genes, e.g. Nanog, Oct3/4, Sox2, and Sox9, were found in iCCA cells grown as 3D tumorspheres. A kinase inhibitor screening library was then performed on iCCA tumorspheres. Our initial screening demonstrated that 11 out of the top 50 kinase inhibitors that effectively decrease viability of iCCA tumorspheres belongs to the insulin-like growth factor-1 receptor (IGF-1R)/phosphoinositide-3-kinase (PI3K)/protein kinase B (PKB/AKT) axis. Additionally, these inhibitors increase cell apoptosis, judged by the caspase 3/7 activity, within iCCA tumorspheres. Conversely, IGF-1 treatment which is sufficient to induce activation of IGF-1R and AKT also enhances cell viability and decrease cell apoptosis in iCCA. Taken together, our data demonstrate that IGF-1R/PI3K/AKT axis is crucial for survival of iCCA cells with stemness characteristics and this pathway could be a potential therapeutic target in iCCA. Citation Format: Chotirat Rattanasinchai, Chidchanok Chornkrathok, Donlaporn Sriphan, Panida Navasumrit, Mathuros Ruchirawat. Kinase library screening identifies IGF-1R/PI3K/AKT axis as a crucial pathway for survival of intrahepatic cholangiocarcinoma cells with stemness characteristics. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5806.