Inhibition Of Insulin-like Growth Factor Research Articles

Proteomic insights uncover enhanced neurotherapeutic potential in conditioned mesenchymal stem cell-derived extracellular vesicles

Extracellular vesicles (EVs) show more potential as therapeutic agents for treating neurological disorders than their parent cells like MSCs. Notably, the therapeutic efficacy of MSCs can be boosted by inflammation factors and oxidative stressors. Here, we investigated the impact of activated microglial cell supernatant (Con1) and hydrogen peroxide (Con2) on MSCs and collected their derived EVs, followed by using high-resolution mass spectrometry to analyze MSC-EV proteomic and phosphoproteomic profiles, and verified the indicated functional protein and phosphorylated kinase as well. Our findings showed that both Con1 and Con2 EVs exhibited characteristic features of extracellular vesicles and possessed greater anti-inflammatory and antioxidant activity compared to unconditioned MSC-EVs. Omics analysis revealed alterations in protein expression and phosphorylation associated with inflammation and oxidation biological processes and signaling pathways, as well as signified the post-translational modification of proteins in Con1/2 EVs. Importantly, we identified that the anti-inflammatory role of MSC-EVs was linked to the serine/threonine kinase phosphorylation, and inhibition of insulin-like growth factor 1 receptor (IGF1R) reduced the antioxidant activity of MSC-EVs. This report documented the changed protein expression and phosphorylated patterns of Con1/2 EVs, and provided insights into the functionalization mode of MSC-EVs, suggesting the enhanced neurotherapeutic potential of conditioned EVs in the treatment of neurological diseases.

Aminophylline Improves Ventilator-Induced Diaphragmatic Dysfunction by Targeting IGF-1-FOXO1-MURF1 Pathway.

The usage of life-saving mechanical ventilation (MV) could cause ventilator-induced diaphragmatic dysfunction (VIDD), increasing both mortality and morbidity. Aminophylline (AP) has the potential to enhance the contractility of animal skeletal muscle fibers and improve the activity of human respiratory muscles, and the insulin-like growth factor-1 (IGF-1)- forkhead box protein O1 (FOXO1)-muscle RING finger-1 (MURF1) pathway plays a crucial role in skeletal muscle dysfunction. This study aimed to investigate the impact of AP on VIDD and to elucidate the role of the IGF-1-FOXO1-MURF1 pathway as an underlying mechanism. Rat models of VIDD were established through MV treatment. IGF-1 lentiviral (LV) interference (LV-IGF-1-shRNA; controlled by lentiviral negative control LV-NC) was employed to inhibit IGF-1 expression and thereby block the IGF-1-FOXO1-MURF1 pathway. Protein and mRNA levels of IGF-1, FOXO1, and MURF1 were assessed using western blot and real-time reverse transcriptase-polymerase chain reaction (RT-qPCR), respectively. Diaphragm contractility and morphometry were examined through measurement of compound muscle action potentials (CMAPs) and hematoxylin and eosin (H&E) staining. Oxidative stress was evaluated by levels of hydrogen peroxide (H2O2), superoxide dismutase (SOD), antioxidant glutathione (GSH), and carbonylated protein. Mitochondrial stability was assessed by measuring the mitochondrial membrane potential (MMP), and mitochondrial fission and mitophagy were examined through protein levels of dynamin-related protein 1 (DRP1), mitofusin 2 protein (MFN2), phosphatase and tensin homolog (PTEN)-induced kinase 1 (PINK1), and Parkin (western blot). Apoptosis was evaluated using the terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate (UTP) nick-end labeling (TUNEL) assay and levels of Bax, B-cell lymphoma 2 (BCL-2), and Caspase-3. Levels of Atrogin-1, neuronally expressed developmentally downregulated 4 (NEDD4), and muscle ubiquitin ligase of SCF complex in atrophy-1 (MUSA1) mRNA, as well as ubiquitinated protein, were utilized to determine protein degradation. Furthermore, the SUnSET (surface sensing of translation) method was employed to determine rates of protein synthesis. MV treatment upregulated IGF-1 while downregulated FOXO1 and MURF1 (p < 0.05). AP administration reversed IGF-1, FOXO1 and MURF1 (p < 0.05), which was suppressed again by IGF-1 inhibition (p < 0.05), demonstrating the blockage of the IGF-1-FOXO1-MURF1 pathway. MV treatment caused decreased CMAP and cross-sectional areas of diaphragm muscle fibers, and increased time course of CMAP (p < 0.05). Additionally, oxidative stress, cell apoptosis, and protein degradation were increased and mitochondrial stability was decreased by MV treatment (p < 0.05). Conversely, AP administration reversed all these changes induced by MV, but this reversal was disrupted by the blockage of the IGF-1-FOXO1-MURF1 pathway. In this study, MV treatment induced symptoms of VIDD in rats, which were all effectively reversed by AP regulating the IGF-1-FOXO1-MURF1 pathway, demonstrating the potential of AP in ameliorating VIDD.

Pharmacokinetics and pharmacodynamics of a pasireotide subcutaneous depot (CAM4071) and comparison with immediate and long-acting release pasireotide.

To assess the pharmacokinetics, pharmacodynamics, safety and tolerability of subcutaneous depot CAM4071, a novel, ready-to-use pasireotide formulation. This was a phase 1, randomised, open-label study in healthy volunteers. After a single 600 µg dose of pasireotide immediate release (IR), participants were randomised to one of eight groups to receive either a CAM4071 upper thigh (5, 10, 20, 40 or 80 mg) or buttock (20 mg) injection or multiple pasireotide IR 900 µg upper thigh injections twice daily or a single pasireotide long-acting release (LAR) 60 mg intramuscular buttock injection. Ninety-four participants were randomised. For all CAM4071 doses, initial pasireotide release was relatively rapid compared to pasireotide LAR and sustained over the 2-month observation period, with a slow decay in plasma concentrations. CAM4071 maximum plasma concentrations increased slightly greater than dose proportionally; area under the curve extrapolated to infinity increased approximately dose proportionally. Relative bioavailability of pasireotide for different doses of CAM4071 versus pasireotide IR 600 μg ranged from 0.752 (90% confidence interval [CI]: 0.58, 0.98) to 1.68 (1.32, 2.14), and versus pasireotide LAR: 0.517 (0.37, 0.72) to 1.15 (0.84, 1.58). CAM4071 doses >5 mg exhibited rapid initial reductions of insulin-like growth factor 1 (IGF-1) compared to pasireotide LAR. Maximum IGF-1 inhibition was greatest for CAM4071 80 mg. CAM4071 injections ≤40 mg were well tolerated and comparable with currently available pasireotide formulations. CAM4071 provided long-acting release of pasireotide over at least one month, with high bioavailability and onset and duration of IGF-1 suppression similar to pasireotide LAR. EudraCT: 2014-003783-20.

Mollugin suppresses proliferation and drives ferroptosis of colorectal cancer cells through inhibition of insulin-like growth factor 2 mRNA binding protein 3/glutathione peroxidase 4 axis

Increasing researches have demonstrated that targeting ferroptosis might be a new conceptual avenue to treat colorectal cancer (CRC). Mollugin is a phytochemical isolated from Rubia cordifolia L. with antitumor activity. However, whether ferroptosis mediates the antitumor activity of mollugin in CRC has not been explored. Our study aims to investigate the antitumor and pro-ferroptosis effects, and mechanisms of mollugin in CRC. We found that mollugin led to ferroptosis in CRC cells, resulting in reduced GSH level and elevated levels of ROS, Fe2+, and MDA. Mollugin treatment caused obvious decrease in cell viability and proliferation in CRC cells, which were aggravated by ferroptosis inducer erastin and attenuated by ferroptosis inhibitor ferrostatin-1. Tumor xenografts experiments proved that mollugin suppressed the tumor growth, while treatment with ferrostatin-1 attenuated the antitumor activity of mollugin in vivo. Integrated bioinformatics analysis showed that insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) was highly expressed in CRC tissues and indicated poor prognosis. Further investigation indicated that the IGF2BP3/glutathione peroxidase 4 (GPX4) axis was involved in mollugin-regulated ferroptosis in CRC. In conclusions, Mollugin suppresses proliferation and drives ferroptosis of CRC cells by inhibiting the IGF2BP3/GPX4 axis, suggesting that mollugin may be a potential therapeutic option for CRC.

Cav3.2 T-Type calcium channels downregulation attenuates bone cancer pain induced by inhibiting IGF-1/HIF-1α signaling pathway in the rat spinal cord

BackgroundBone cancer pain (BCP) is one of the most ubiquitous and refractory symptoms of cancer patients that needs to be urgently addressed. Substantial studies have revealed the pivotal role of Cav3.2 T-type calcium channels in chronic pain, however, its involvement in BCP and the specific molecular mechanism have not been fully elucidated. MethodsThe expression levels of Cav3.2, insulin-like growth factor 1(IGF-1), IGF-1 receptor (IGF-1R) and hypoxia-inducible factor-1α (HIF-1α) were detected by Western blot in tissues and cells. X-ray and Micro CT used to detect bone destruction in rats. Immunofluorescence was used to detect protein expression and spatial location in the spinal dorsal horn. Electrophoretic mobility shift assay used to verify the interaction between HIF-1α and Cav3.2. ResultsThe results showed that the expression of Cav3.2 channel was upregulated and blockade of this channel alleviated mechanical allodynia and thermal hyperalgesia in BCP rats. Additionally, inhibition of IGF-1/IGF-1R signaling not only reversed the BCP-induced upregulation of Cav3.2 and HIF-1α, but also decreased nociceptive hypersensitivity in BCP rats. Inhibition of IGF-1 increased Cav3.2 expression levels, which were abolished by pretreatment with HIF-1α siRNA in PC12 cells. Furthermore, nuclear HIF-1α bound to the promoter of Cav3.2 to regulate the Cav3.2 transcription level, and knockdown of HIF-1α suppresses the IGF-1-induced upregulation of Cav3.2 and pain behaviors in rats with BCP. ConclusionThese findings suggest that spinal Cav3.2 T-type calcium channels play a central role during the development of bone cancer pain in rats via regulation of the IGF-1/IGF-1R/HIF-1α pathway.

Microglial CD11b Knockout Contributes to Axonal Debris Clearance and Axonal Degradation Attenuation via IGF-1 After Acute Optic Nerve Injury.

Microglial clearance of axonal debris is an essential response for management of traumatic optic neuropathy. Inadequate removal of axonal debris leads to increased inflammation and axonal degeneration after traumatic optic neuropathy. The present study investigated the role of CD11b (Itgam) in axonal debris clearance and axonal degeneration. Western blot and immunofluorescence were used to detect CD11b expression in the mouse optic nerve crush (ONC) model. Bioinformatics analysis predicted the possible role of CD11b. Cholera toxin subunit B (CTB) and zymosan were used to assay phagocytosis by microglia in vivo and in vitro, respectively. CTB was also used to label functionally intact axons after ONC. CD11b is abundantly expressed after ONC and participates in phagocytosis. Microglia from Itgam-/- mice exhibited more significant phagocytosis of axonal debris than wild-type microglia. In vitro experiments confirmed that the CD11b gene defect in M2 microglia leads to increased insulin-like growth factor-1 secretion and thus promotes phagocytosis. Lastly, following ONC, Itgam-/- mice exhibited elevated expression of neurofilament heavy peptide and Tuj1, along with more intact CTB-labeled axons when compared with wild-type mice. Moreover, the inhibition of insulin-like growth factor-1 decreased CTB labeling in Itgam-/- mice after injury. CD11b limits microglial phagocytosis of axonal debris in traumatic optic neuropathy, as demonstrated by increased phagocytosis with CD11b knockout. The inhibition of CD11b activity may be a novel approach to promote central nerve repair.

Insulin-like growth factor 1 serum levels in different stages of gastric cancer and their association with Helicobacter pylori status

High serum insulin-like growth factor 1 (IGF-1) and positive Helicobacter pylori (H. pylori) may increase the risk of gastric cancer (GC). We aimed to investigate IGF-1 serum levels in different stages of GC patients and their association with H. pylori status. A total of 90 participants, including 60 GC patients and 30 noncancerous (NC) individuals, were included in the present study. IGF-1 serum levels and candidate proteins were assessed using enzyme-linked immunosorbent and immunohistochemistry techniques. Likewise, Giemsa staining was applied to detect H. pylori infection. The candidate genes' expression, including IGF-1R, PI3KCA, AKT1, mTOR1, KRAS, BRAF, and ERK1, was also evaluated by a real-time PCR assay. The results of advanced GC stages indicated a significantly high IHC score for IGF-1R and phosphorylated AKT, mTOR, and ERK proteins compared to the early stages. Moreover, IGF-1 serum levels and the expression of candidate genes were considerably increased in the advanced GC patients compared to the early stages and the positive H. pylori status compared to the negative H. pylori status (P < 0.05). As a result, high IGF-1 serum levels and positive H. pylori status may be correlated with gastric tumor progression, and the inhibition of IGF-1 and the eradication of H. pylori infection might be new therapeutic targets in GC patients.

Inhibition of insulin-like growth factor 2 mRNA-binding protein 1 sensitizes colorectal cancer cells to chemotherapeutics.

Although colorectal cancer (CRC) treatment has seen a remarkable improvement in the recent years, many patients will develop metastasis due to the resistance of cancer cells to chemotherapeutics. Targeting mechanisms driving the resistance of CRC cells to treatment would significantly reduce cases of metastasis and death. Induction of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), a direct target of the Wnt/β-catenin signaling pathway, might promote resistance of CRC cells to treatment via activation of anti-apoptotic pathways and induction of the multidrug resistance (MDR1) membrane transporter that pumps drugs out of the cells. We hypothesized that inhibition of IGF2BP1 will sensitize CRC cells to chemotherapeutics. We used CRC cell lines with different status of activation of Wnt signaling to show that inhibition of IGF2BP1 potentiates the anti-growth and anti-proliferative effects of chemotherapeutics on CRC cells with activated Wnt/β-catenin signaling pathway. We observed that the inhibition of IGF2BP1 significantly increases apoptosis in the same cells. A remarkable reduction in the migratory capability of those cells was noted as well. We found that inhibition of IGF2BP1 is sufficient to decrease the resistance of chemotherapy-resistant cancer cells with activated Wnt/β-catenin signaling pathway. These findings portray IGF2BP1 as a good candidate for CRC therapy.

Aberrant astrocyte protein secretion contributes to altered neuronal development in multiple models of neurodevelopmental disorders.

Astrocytes negatively impact neuronal development in many models of neurodevelopmental disorders (NDs); however, how they do this, and if mechanisms are shared across disorders, is not known. In this study, we developed a cell culture system to ask how astrocyte protein secretion and gene expression change in three mouse models of genetic NDs (Rett, Fragile X and Down syndromes). ND astrocytes increase release of Igfbp2, a secreted inhibitor of insulin-like growth factor (IGF). IGF rescues neuronal deficits in many NDs, and we found that blocking Igfbp2 partially rescues inhibitory effects of Rett syndrome astrocytes, suggesting that increased astrocyte Igfbp2 contributes to decreased IGF signaling in NDs. We identified that increased BMP signaling is upstream of protein secretion changes, including Igfbp2, and blocking BMP signaling in Fragile X and Rett syndrome astrocytes reverses inhibitory effects on neurite outgrowth. This work provides a resource of astrocyte-secreted proteins in health and ND models and identifies novel targets for intervention in diverse NDs.

Сurrent status of adrenocortical cancer therapy

Adrenocarcinoma is a rare adrenal disease with an unfavorable prognosis. Adrenocortical cancer therapy is characterized by insufficient effectiveness. This review covers the generally accepted adrenocortical carcinoma therapy methods -mitotane alone or in combination with chemotherapeutic agents. It also provides perspectives from the novel agents` studies in adrenocarcinoma patients. Information about the use of insulin-like growth factor inhibitors, multikinase inhibitors, anti-PD-1/PD-L1 is given.

DR1 Activation Inhibits the Proliferation of Vascular Smooth Muscle Cells through Increasing Endogenous H2S in Diabetes.

Tissue ischemia and hypoxia caused by the abnormal proliferation of smooth muscle cells (SMCs) in the diabetic state is an important pathological basis for diabetic microangiopathy. Studies in recent years have shown that the chronic complications of diabetes are related to the decrease of endogenous hydrogen sulfide (H2S) in diabetic patients, and it has been proven that H2S can inhibit the proliferation of vascular SMCs (VSMCs). Our study showed that the endogenous H2S content and the expression of cystathionine gamma-lyase (CSE), which is the key enzyme of H2S production, were decreased in arterial SMCs of diabetic mice. The expression of PCNA and Cyclin D1 was increased, and the expression of p21 was decreased in the diabetic state. After administration of dopamine 1-like receptors (DR1) agonist SKF38393 and exogenous H2S donor NaHS, the expression of CSE was increased and the change in proliferation-related proteins caused by diabetes was reversed. It was further verified by cell experiments that SKF38393 activated calmodulin (CaM) by increasing the intracellular calcium ([Ca2+]i) concentration, which activated the CSE/H2S pathway, enhancing the H2S content in vivo. We also found that SKF38393 and NaHS inhibited insulin-like growth factor-1 (IGF-1)/IGF-1R and heparin-binding EGF-like growth factor (HB-EGF)/EGFR, as well as their downstream PI3K/Akt, JAK2/STAT3 and ERK1/2 pathways. Taken together, our results suggest that DR1 activation up-regulates the CSE/H2S system by increasing Ca2+-CaM binding, which inhibits the IGF-1/IGF-1R and HB-EGF/EGFR pathways, thereby decreasing their downstream PI3K/Akt, JAK2/STAT3 and ERK1/2 pathways to achieve the effect of inhibiting HG-induced VSMCs proliferation.

Insulin-like growth factor reduced against decabromodiphenyl ether-209-induced neurodevelopmental toxicity in vivo and in vitro.

How to reduce the neurodevelopmental toxicity of decabromodiphenyl ether (PBDE-209) remains unclear. This study investigated neurodevelopmental toxicity of PBDE-209 and the protective effects of insulin-like growth factor-1 (IGF-1). Pregnant Sprague-Dawley rats were treated with PBDE-209 and IGF-1, and the offspring were subjected to the Morris Water Maze test. Hippocampal neurons were cultured with PBDE-209 and IGF-1 or the PI3K inhibitor or MEK inhibitor for cell viability, apoptosis, immunofluorescence, and Western blot assays. Prenatal PBDE-209 exposure impaired the learning and memory ability of rats by delaying the mean latency to the platform compared, whereas prenatal treatment with IGF-1 treatment improved the learning and memory ability. In vitro, treatment of primary cultured hippocampal neural stem cells (H-NSCs) with PBDE-209 reduced cell proliferation and differentiation, but induced apoptosis. In contrast, IGF-1 treatment antagonized the cytotoxic effects of PBDE-209 in H-NSCs in vitro. At the gene level, IGF-1 inhibition of PBDE-209-induced cell cytotoxicity was through the activation of the PI3K/AKT and MEK/ERK signaling pathways in vitro because the effect of IGF-1 was blocked by the AKT inhibitor LY294002 and the ERK1/2 inhibitor PD98059. Prenatal PBDE-209 exposure impaired the learning and memory ability of rats, whereas IGF-1 treatment was able to inhibit the neurodevelopmental toxicity of PBDE-209 by activation of the PI3K/AKT and ERK1/2 cell pathways.

Abstract 3088: Identification of insulin-like growth factor 1 receptor as a novel and specific target of heparin hexasaccharide that selectively inhibits cancer stem cells

Abstract Introduction: Earlier, we discovered that heparin hexasaccharide (HS06), but not shorter or longer polymeric glycosaminoglycan (GAGs), selectively inhibit cancer stem cells (CSCs). Insulin-like growth factor-1 (IGF1) receptor (IGF1R) plays a critical role in regulating CSC phenotype. However, unlike many growth factor receptors, GAG and IGF1R interaction and consequences have not been characterized. Methods: Colon cancer HT29 and HCT-116 cells were grown on ornithine as spheroids. Stable IGF1R knockdown cells (KD) were generated using shRNA transfection and selection. Immunofluorescence (IF) studies were performed with fluorescent-tagged HS06, GAG polymer, and pIGF1R antibody. Images were obtained using a Cytation 5 and analyzed using Gen5. Computational and molecular dynamics studies were employed to determine the binding site and nature of the interaction between HS06 and IGF1R. The impact of this interaction on activation and CSC phenotype was determined using standard techniques such as western blotting and Q-PCR. Results: Fluorescent-tagged HS06 and polymeric GAG, both bound to the colon cancer cell membrane (CM) in a dose-dependent fashion. Intriguingly, HS06 but not polymeric GAG's binding to the cell surface was abolished by IGF1R knockdown, suggesting IGF1R as a specific target HS06. Computational studies identified L1 and CR domain in the N-terminus of IGF1R as a binding site for HS06 but not multimeric GAGs. Intriguingly, there is an overlap between HS06 and IGF1 binding sites on IGF1R. Pretreatment with three different IGF1R N-terminus targeting antibodies reversed HS06 binding to CM, suggesting the N-terminus domain as a likely site of HS06 and IGF1R interactions. Additionally, IGF1 pretreatment also reversed the binding of HS06 in a dose-dependent fashion. Functionally, HS06 (but not polymeric GAG) inhibited IGF1R phosphorylation and CSC phenotype (2° spheroids and/or CSC markers). Both these effects were reversed by pretreatment with IGF1 suggesting competitive inhibition of IGF1 induced activation of IGF1R by HS06. Molecular dynamics studies identified key N-terminus residues in the L1 and CR domain of the N-terminus portion of the IGF1R distinct from IGF1 binding residues. Key basic amino acid residues that were predicted to bind specifically to HS06 in MD simulation have been observed to be mutated in cancer, and IF studies in HT29 cells expressing HS06 binding-site mutant proteins are ongoing. Conclusion: We have uncovered a novel, specific and functionally relevant interaction between HS06 and the N-terminal domain of IGF1R. The HS06-IGF1R interaction induces competitive inhibition of IGF1 induced activation of IGF1R and CSC phenotype. The findings significantly impact an understanding of GAG mediated regulation of the CSC phenotype and present a highly novel mechanism of targeting IGF1R to develop novel anti-cancer agents Citation Format: Rio S. Boothello, Jyothi C. Sistla, Nehru Viji Sankaranarayanan. Identification of insulin-like growth factor 1 receptor as a novel and specific target of heparin hexasaccharide that selectively inhibits cancer stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3088.

The Roles of Insulin-Like Growth Factor Binding Protein Family in Development and Diseases.

The insulin-like growth factor (IGF) system comprises ligands of IGF-I/II, IGF receptors (IGFR), IGF binding proteins (IGFBPs), and IGFBP hydrolases. The IGF system plays multiple roles during various disease development as IGFs are widely involved in cell proliferation and differentiation through regulating DNA transcription. Meanwhile, IGFBPs, which are mainly synthesized in the liver, can bind to IGFs and perform two different functions: either inhibition of IGFs by forming inactive compounds with IGF or enhancement of the function of IGFs by strengthening the IGF-IGFR interaction. Interestingly, IGFBPs may have wider functions through IGF-independent mechanisms. Studies have shown that IGFBPs play important roles in cardiovascular disease, tumor progression, fetal growth, and neuro-nutrition. In this review, we emphasize that different IGFBP family members have common or unique functions in numerous diseases; moreover, IGFBPs may serve as biomarkers for disease diagnosis and prediction.

Abstract CT165: An open label, multi-cohort, phase Ib study of xentuzumab and abemaciclib: Preliminary results from the advanced non-small cell lung cancer (NSCLC) cohort

Abstract Introduction: Insulin-like growth factor (IGF) signaling and the cyclin D-cyclin-dependent kinase (CDK) 4 &amp; 6-retinoblastoma pathway are implicated in cancer progression and treatment resistance. Activation of the IGF receptor results in upregulation of cyclin D1 and progression through the cell cycle. Dual inhibition of IGF and CDK 4 &amp; 6 should lead to decreased cell proliferation through disruption of cell-cycle progression. This phase Ib trial assessed safety and preliminary efficacy of xentuzumab, an IGF-ligand neutralizing antibody, in combination with abemaciclib, a CDK 4 &amp; 6 inhibitor. In a dose-finding cohort in patients (pts) with solid tumors, the recommended phase II dose was determined as xentuzumab 1000 mg weekly intravenously plus abemaciclib 150 mg every 12 hours (Q12h) orally. Here, we present data from an expansion cohort in pts with NSCLC. Methods: Eligible pts had stage IV NSCLC with measurable disease which had progressed after platinum-based chemotherapy and immunotherapy, and had either received 1-2 prior chemotherapies for advanced/metastatic disease or were judged ineligible for further standard second-line chemotherapy. Prior CDK 4 &amp; 6 inhibitor therapy was not permitted. Pts received xentuzumab 1000 mg weekly plus abemaciclib 150 mg Q12h until disease progression or intolerability of study medication. The primary endpoint was objective response defined as best overall response of complete response or partial response (PR) per RECIST 1.1. Secondary endpoints included progression-free survival (PFS). Results: 25 pts with NSCLC were treated (17 male [68%], median age 64 years [range 53-76]). 4 pts remained on treatment at time of analysis. Median treatment exposure was 1.6 months (range 0.5-19.7). Of 19 pts evaluable for response, 1 had a best overall response of PR (65% target lesion shrinkage), 9 had stable disease (duration ≥24 weeks in 3 pts) and 9 had progressive disease. Median PFS was 2.1 months (95% CI 1.2-5.3). All pts experienced adverse events (AEs) and 23 experienced treatment-related AEs (TRAEs), most commonly diarrhea (n=15; 60%), nausea (n=10; 40%) and platelet count decreased (n=8; 32%). The most common grade ≥3 TRAEs were thrombocytopenia (n=4; 16%) and neutropenia (n=3; 12%). No AEs of hyperglycemia or blood glucose increased were reported. Serious AEs were experienced by 13 pts (52%). 2 pts had fatal serious AEs due to disease progression and respiratory failure. Conclusion: The combination of xentuzumab and abemaciclib showed preliminary efficacy in pts with NSCLC who had progressed on chemotherapy and an immune checkpoint inhibitor. One PR was reported. The combination had a manageable safety profile. Citation Format: Patricia LoRusso, Javier García-Corbacho, Fadi S. Braiteh, Anthony Gonçalves, Francesco Ricci, Hiroji Iwata, Marta Capelán, Marie Paule Sablin, Aleix Prat, Molly Catherine Hardebeck, Marta Puig, Dennis Chin-Lun Huang, Mingchi Hsu, Douglas Yee. An open label, multi-cohort, phase Ib study of xentuzumab and abemaciclib: Preliminary results from the advanced non-small cell lung cancer (NSCLC) cohort [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT165.

Insulin growth factor-1 pathway in cervical carcinoma cancer stem cells.

Cancer stem cells (CSC) drive tumour progression and are implicated in relapse and resistance to conventional cancer therapies. Identification of differentially expressed genes by gene expression (GEP) profiling may help identify the differentially activated signalling pathways in cancer stem cells as opposed to bulk tumour cells which will provide new insights into cancer stem cell biology and aid in identification of novel therapeutic targets. Our study focused on the inhibition of CSC from cervical cancer cell lines by targeting insulin-like growth factor (IGF), which was identified by differential GEP. Targeted inhibition of IGF-1 by JB-1 trifluoroacetate (inhibitor of IGF) was carried out in SiHa, RSBS-14 and RSBS-43 cervical cancer derived cell lines. Effect of cisplatin was also evaluated. Inhibition of IGF-1 signalling was confirmed by demonstration of reduction in p-Akt levels. The cell biological effects of IGF-1 inhibition included an increase in G2M/S fraction, increased apoptosis and decreased invasive ability. JB-1 and cisplatin showed synergism. However, transcript levels of stemness and EMT markers showed variable levels following IGF inhibition. Overall, this proof-of-concept study has shown that IGF-1 is an attractive target for inhibition of CSC in invasive cervical cancer.

IGF1 Knockdown Hinders Myocardial Development through Energy Metabolism Dysfunction Caused by ROS-Dependent FOXO Activation in the Chicken Heart.

Insulin-like growth factor 1 (IGF1) is a multifunctional cellular regulatory factor that can regulate cell growth and development by mediating growth hormone stimulation. However, the mechanism of IGF1 dysfunction in cardiomyocyte development is seldom reported. To study this, we employed the models of IGF1 knockdown in chicken embryo in vivo and in cardiomyocytes in vitro. We detected the antioxidant capacity, PI3K/Akt pathway, energy metabolism-related genes, and myocardial development-related genes. Our results revealed that the low expression of IGF1 can significantly suppress the antioxidant capacity and increase the ROS (P < 0.05) levels, activating the AMPK and PI3K pathway by inhibiting the expression of IRS1. We also found that myocardial energy metabolism is blocked through IGF1, GLUT, and IGFBP inhibition, further inducing myocardial developmental disorder by inhibiting Mesp1, GATA, Nkx2.5, and MyoD expression. Altogether, we conclude that low IGF1 expression can hinder myocardial development through the dysfunction of energy metabolism caused by ROS-dependent FOXO activation.

Insulin-Like Growth Factor 1 Regulates Acute Inflammatory Lung Injury Mediated by Influenza Virus Infection.

The acute inflammatory lung injury is an important cause of death due to influenza A virus (IAV) infection. Insulin-like growth factor 1 (IGF1) played an important role in the regulation of inflammation in the immune system. To investigate the role of IGF1 in IAV-mediated acute inflammatory lung injury, the expression of IGF1 and inflammatory cytokines was tested after IAV A/Puerto Rico/8/1934 (H1N1; abbreviated as PR8) infection in A549 cells. Then, a BALB/c mouse model of PR8 infection was established. On days 3, 5, 7, and 9 post-infection, the mice lung tissue was collected to detect the expression changes in IGF1 mRNA and protein. The mice were divided into four groups: (1) PBS (abbreviation of phosphate buffered saline); (2) PR8 + PBS; (3) PR8 + IGF1; and (4) PR8 + PPP (abbreviation of picropodophyllin, the IGF1 receptor inhibitor). The body weight and survival rate of the mice were monitored daily, and the clinical symptoms of the mice were recorded. On day 5 post-infection, the mice were sacrificed to obtain the serum and lung tissues. The expression of inflammatory cytokines in the serum was detected by enzyme linked immunosorbent assay; lung injury was observed by hematoxylin-eosin staining; the viral proliferation in the lung was detected by real-time quantitative PCR; and the protein expression of the main molecules in the phosphatidylinositol-3-kinases/protein kinase B (PI3K/AKT) and mitogen-activated protein kinase (MAPK) signaling pathways was detected by Western blot. It was found that IGF1 expression is upregulated in A549 cells and BALB/c mice infected with PR8, whereas IGF1 regulated the expression of inflammatory cytokines induced by PR8 infection. Overexpression of IGF1 aggravated the IAV-mediated inflammatory response, whereas the inhibition of IGF1 receptor reduced such inflammatory response. The phosphorylation of IGF1 receptor triggered the PI3K/AKT and MAPK signaling pathways to induce an inflammatory response after IAV infection. Therefore, IGF1 plays an important immune function in IAV-mediated acute inflammatory lung injury. IGF1 may provide a therapeutic target for humans in response to an influenza outbreak, and inhibition of IGF1 or IGF1 receptor may represent a novel approach to influenza treatment.

Loss of insulin-like growth factor-1 signaling in astrocytes disrupts glutamate handling.

Insulin-like Growth Factor-1 (IGF-1) has been studied extensively for its ability to promote neuronal growth and excitability. Declining levels of IGF-1 have been correlated with impaired learning and memory as well as an increased risk of neurodegenerative diseases. While neuronal regulation by IGF-1 is well understood, the role of IGF-1 in influencing astrocyte function requires further exploration. Astrocytes regulate many aspects of the brain microenvironment, including controlling glutamate-glutamine cycling, which ultimately supports neuronal metabolism, neurotransmission, and protection from over stimulation. In this study, we examined whether IGF-1 acts through its cognate receptor, IGFR, to alter astrocytic glutamate handling. We utilized both small molecule IGFR inhibitors and Cre-driven genetic approaches to reduce IGFR in vivo and in cultured rodent astrocytes. When IGFR was knocked out of primary astrocytes derived from igfrf/f mice using AAV5-CMV-Cre, significant reductions in glutamate uptake were observed. Similarly, inhibition of IGFR with picropodophyllotoxin for 2h, as well as 24h, reduced glutamate uptake in vitro. Mechanistically, short-term inhibition of IGFR resulted in a significant decrease in glutamate transporter availability on the cell surface, as assessed by biotinylation. Long-term inhibition of IGFR led to significant reductions in mRNA expression of glutamate transport machinery, as assessed with qPCR. Reduced glutamate transporter mRNA was also observed in the brains of astrocyte-specific IGFR-deficient mice, three to four months after knock-out was induced with tamoxifen. Interestingly, long-term IGF-1 inhibition also resulted in an increase in adenosine triphosphate-stimulated glutamate release, though no change in adenosine triphosphate-stimulated calcium flux was observed nor were any changes in purinergic receptor protein expression. Together, these data suggest that reduced IGF-1 signaling will favor an accumulation of extrasynaptic glutamate, which may contribute to neurodegeneration in disease states where IGF-1 levels are low. Cover Image for this issue: doi: 10.1111/jnc.14534.

Abstract 4667: A synergistic combination strategy for optimal inhibition of colon cancer stem cells: Simultaneous inhibition of Insulin-like growth factor-1 receptor-AKT-mammalian target of rapamycin axis and the mevalonate-isoprenoid biosynthetic pathway

Abstract Introduction: Targeting cancer stem cells (CSCs) is an attractive new paradigm to achieve long-term remission/cure. The mevalonate-isoprenoid biosynthetic (MIB) pathway is critical in the regulation of colonic CSCs. However, feedback activation of SREBP2 following inhibition of the MIB pathway reduces the efficiency of the latter strategy. We described that Insulin-like growth factor-1 receptor-AKT-mammalian target of rapamycin (InAT) axis inhibits CSCs via inhibition of the MIB pathway at a level distinct from the target of statin - HMGCR, while simultaneously inhibiting SREBP2. Hence, we hypothesized that combining a MIB pathway inhibitor with the InAT axis inhibition will result in optimal inhibition of CSCs. Methods: Four possible combinations with the MIB pathway inhibitors (Simvastatin or zoledronate) and an InAT axis inhibitors (OSI-906) or Everolimus were tested against spheroids from 12 colorectal cancer cells. Synergistic effect of the combinations was determined using Chou Talalay method (Calcusyn). Most promising combinations were examined in an in vivo model of Dual high CSCs (CD133+/CXCR4+) induced xenografts to assess tumor volume, and ex vivo CSC phenotype (spheroid formation and CSC marker expression) in xenograft-derived cells. Results: OSI-906 + Simvastatin, as well as Everolimus + simvastatin, showed a robust synergistic effect (Combination index &amp;lt;0.75) in a majority of colon cancer cells which was independent of mutation in PI3K/mTOR or RAS pathways. In fact, both the combinations showed a significantly higher inhibition of Dual high CSCs-induced xenograft volume as well as ex-vivo spheroid formation (2°→4°) and CSC markers (CD133, DCLK1, LGR etc.) than either agents alone or vehicle controls in two model of colon cancer HCT-116 (MSI high, KRAS mut), HT29 (MSS, KRAS mut). Importantly, Simvastatin treatment failed to inhibit SREBP2 levels. However, InAT axis inhibitors caused a significant inhibition of SREBP2 and the MIB pathway genes. In fact, inhibition of the MIB pathway at the level of isopentenyl-diphosphate delta isomerase 1 (IDI1) was critical for simultaneous inhibition of the MIB pathway and InAT axis to attenuate CSC self-renewal as supplementation with DMAPP, and FPP, but not mevalonate or IPP, reversed the effect of the combination on CSCs. Conclusion: Orally deliverable and combinations of the FDA-approved drugs targeting the MIB pathway and the InAT axis cause optimum inhibition of colonic CSCs through downregulation of SREBP2, achieving maximal inhibition of the MIB pathway. Note: This abstract was not presented at the meeting. Citation Format: Chetna Sharon, Rio Boothello, Alberto Vera, Bhaumik B. Patel. A synergistic combination strategy for optimal inhibition of colon cancer stem cells: Simultaneous inhibition of Insulin-like growth factor-1 receptor-AKT-mammalian target of rapamycin axis and the mevalonate-isoprenoid biosynthetic pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4667.