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Background: The insulin-like growth factor 1 receptor (IGF-1R) and the thyrotropin receptor (TSH-R) are expressed on orbital cells and thyrocytes. These receptors are targeted in autoimmune-induced thyroid eye disease (TED). Effective therapeutic treatment of TED inhibits activation of the IGF-1R/TSH-R complex. Methods: The inhibitory effect on cell proliferation of a small molecule targeting IGF-1R phosphorylation (Linsitinib) was investigated in an IGF-1R expressing cell line and a Chinese Hamster Ovary (CHO) cell line overexpressing TSH-R. An IGF-1R monoclonal antibody antagonist, Teprotumumab served as control. Both cell lines were plated in a 96-well format and treated with both compounds for 24 hours. After addition of tetrazolium, absorbance was measured. The apoptosis marker caspase-3/7 activity was measured. The half-maximal inhibitory concentration (IC50) of TSH-R-Ab induced stimulation (stimulatory monoclonal antibody, mAb, M22) of the TSH-R cell line was evaluated with a cell-based bioassay for blocking TSH-R-Ab. Cells were treated with ten rising concentrations of either Linsitinib, Linsitinib + Metformin, Teprotumumab, or a blocking TSH-R mAb (K1-70). Results: Linsitinib strongly inhibited the proliferation of both cell lines at several concentrations: 31,612.5 ng/mL (IGF-1R cell line -78%, P=0.0031, TSH-R cell line -75%, P=0.0059), and at 63,225 ng/mL (IGF-1R cell line -73%, P=0.0073, TSH-R cell line -73%, P=0.0108). Linsitinib induced apoptosis of both cell lines, both morphologically confirmed and with an increased caspase-3/7 activity at concentrations of 31,612.5 ng/mL (IGF-1R cell line P=0.0158, TSH-R cell line P=0.0048) and 63,225 ng/mL (IGF-1R cell line P=0.0005, TSH-R cell line P=0.0020). Linsitinib markedly inhibited proliferation of the IGF-1R cell line at all concentrations compared to Teprotumumab (P=0.0286). Teprotumumab inhibition was significant only at 15,806.25 ng/mL with the TSH-R cell line (-15%, P=0.0396). In addition, in the TSH-R-Ab blocking bioassay, Linsitinib and the tested compounds demonstrated strong inhibition across all ten dilutions (100%). Conclusions: Linsitinib effectively induces apoptosis and inhibits proliferation of both IGF-1R and TSH-R expressing target cells, therefore demonstrating its therapeutic potential to block the reported crosstalk of the two mediators in autoimmune TED. [ABSTRACT FROM AUTHOR]

Abstract To elucidate the role of IGF1R inhibition in the pathogenesis of Graves’ orbitopathy (GO), the effects of linsitinib (Lins) on a recombinant human TSHR antibody (M22) and IGF1 to activate TSHR and IGF1R of human orbital fibroblasts (HOFs) obtained from patients without GO (HOFs) and patients with GO (GHOFs) were studied using in vitro three-dimensional (3D) spheroid models in addition to their 2D planar cell culture. For this purpose, we evaluated 1) cellular metabolic functions by using a seahorse bioanalyzer (2D), 2) physical properties including size and stiffness of 3D spheroids, and mRNA expression of several extracellular matrix (ECM) proteins, their modulators (CCL2 LOX, CTGF, MMPs), ACTA2 and inflammatory cytokines (IL1β, IL6). Administration of IGF1 and M22 induced increases of cellular metabolic functions with the effect on HOFs being much more potent than the effect on GHOFs, suggesting that IGF1R and TSHR of GHOFs may already be stimulated. Lins had effects similar to those of IGF1/M22 on cellular biological functions of HOFs but not on those of GHOFs. As for physical properties of 3D GHOFs spheroids, stiffness but not size was significantly increased by IGF1 and/or M22. In contrast, Lins significantly inhibited the M22-induced increase in stiffness despite the fact that Lins alone had no effect. The mRNA expression levels of several genes of ECM proteins and most of the other genes also fluctuated similarly to the changes in stiffness of 3D spheroids despite the fact that Lins induced up-regulation of inflammatory cytokines and MMP3. The findings presented herein indicate that IGF1R inhibition by Lins may beneficially affect GO-related fibrogenesis.

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

BackgroundThe insulin-like growth factor 1 receptor (IGF-1R) and the thyrotropin receptor (TSH-R) are expressed on orbital cells and thyrocytes. These receptors are targeted in autoimmune-induced thyroid eye disease (TED). Effective therapeutic treatment of TED inhibits activation of the IGF-1R/TSH-R complex.MethodsThe inhibitory effect on cell proliferation of a small molecule targeting IGF-1R phosphorylation (Linsitinib) was investigated in an IGF-1R expressing cell line and a Chinese Hamster Ovary (CHO) cell line overexpressing TSH-R. An IGF-1R monoclonal antibody antagonist, Teprotumumab served as control. Both cell lines were plated in a 96-well format and treated with both compounds for 24 hours. After addition of tetrazolium, absorbance was measured. The apoptosis marker caspase-3/7 activity was measured. The half-maximal inhibitory concentration (IC50) of TSH-R-Ab induced stimulation (stimulatory monoclonal antibody, mAb, M22) of the TSH-R cell line was evaluated with a cell-based bioassay for blocking TSH-R-Ab. Cells were treated with ten rising concentrations of either Linsitinib, Linsitinib + Metformin, Teprotumumab, or a blocking TSH-R mAb (K1-70).ResultsLinsitinib strongly inhibited the proliferation of both cell lines at several concentrations: 31,612.5 ng/mL (IGF-1R cell line -78%, P=0.0031, TSH-R cell line -75%, P=0.0059), and at 63,225 ng/mL (IGF-1R cell line -73%, P=0.0073, TSH-R cell line -73%, P=0.0108). Linsitinib induced apoptosis of both cell lines, both morphologically confirmed and with an increased caspase-3/7 activity at concentrations of 31,612.5 ng/mL (IGF-1R cell line P=0.0158, TSH-R cell line P=0.0048) and 63,225 ng/mL (IGF-1R cell line P=0.0005, TSH-R cell line P=0.0020). Linsitinib markedly inhibited proliferation of the IGF-1R cell line at all concentrations compared to Teprotumumab (P=0.0286). Teprotumumab inhibition was significant only at 15,806.25 ng/mL with the TSH-R cell line (-15%, P=0.0396). In addition, in the TSH-R-Ab blocking bioassay, Linsitinib and the tested compounds demonstrated strong inhibition across all ten dilutions (100%).ConclusionsLinsitinib effectively induces apoptosis and inhibits proliferation of both IGF-1R and TSH-R expressing target cells, therefore demonstrating its therapeutic potential to block the reported crosstalk of the two mediators in autoimmune TED.

Simple Summary: Overexpression and/or mutations of the receptor tyrosine kinase IGF1R are associated with an adverse prognosis in MM but do not appear to have any impact on treatment response, and their functional role in MM is so far unknown. In the current study, we aim to understand the impact of IGF1R mutations on MM cell survival signaling, viability/proliferation and treatment response. We show that IGF1R mutations can impact IGF1R activation and/or downstream signaling and that the combination of the pIGF1R/pINSR inhibitor linsitinib with the second-generation proteasome inhibitor carfilzomib shows promising anti-myeloma activity, regardless of the IGF1R mutation status. High expression of the receptor tyrosine kinase (RTK) insulin-like growth factor-1 receptor (IGF1R) and RTK mutations are associated with high-risk/worse prognosis in multiple myeloma (MM). Combining the pIGF1R/pINSR inhibitor linsitinib with the proteasome inhibitor (PI) bortezomib seemed promising in a clinical trial, but IGF1R expression was not associated with therapy response. Because the oncogenic impact of IGF1R mutations is so far unknown, we investigated the functional impact of IGF1R mutations on survival signaling, viability/proliferation and survival response to therapy. We transfected four human myeloma cell lines (HMCLs) with IGF1RWT, IGF1RD1146N and IGF1RN1129S (Sleeping Beauty), generated CRISPR-Cas9 IGF1R knockouts in the HMCLs U-266 (IGF1RWT) and L-363 (IGF1RD1146N) and tested the anti-MM activity of linsitinib alone and in combination with the second-generation PI carfilzomib in seven HMCLs. IGF1R knockout entailed reduced proliferation. Upon IGF1R overexpression, survival signaling was moderately increased in all HCMLs and slightly affected by IGF1RN1129S in one HMCL, whereby the viability remained unaffected. Expression of IGF1RD1146N reduced pIGF1R-Y1135, especially under serum reduction, but did not impact downstream signaling. Linsitinib and carfilzomib showed enhanced anti-myeloma activity in six out of seven HMCL irrespective of the IGF1R mutation status. In conclusion, IGF1R mutations can impact IGF1R activation and/or downstream signaling, and a combination of linsitinib with carfilzomib might be a suitable therapeutic approach for MM patients potentially responsive to IGF1R blockade. [ABSTRACT FROM AUTHOR]

Summary: While bortezomib has significant benefits in multiple myeloma (MM) therapy, the disease remains incurable due to the invariable development of bortezomib resistance. This emphasises the need for advanced models for preclinical evaluation of new therapeutic approaches for bortezomib‐resistant MM. Here, we describe the development of an orthotopic syngeneic bortezomib‐resistant MM mouse model based on the most well‐characterised syngeneic MM mouse model derived from spontaneous MM‐forming C57BL/KaLwRij mice. Using bortezomib‐resistant 5TGM1 cells, we report and characterise a robust syngeneic mouse model of bortezomib‐resistant MM that is well suited to the evaluation of new therapeutic approaches for proteasome inhibitor‐resistant MM. [ABSTRACT FROM AUTHOR]

Introduction: Graves' disease is an autoimmune disorder caused by autoantibodies against the thyroid stimulating hormone receptor (TSHR). Overstimulation of the TSHR induces hyperthyroidism and thyroid eye disease (TED) as the most common extra thyroidal manifestation of Graves' disease. In TED, the TSHR cross talks with the insulin-like growth factor 1 receptor (IGF-1R) in orbital fibroblasts leading to inflammation, deposition of hyaluronan and adipogenesis. The bone marrow may play an important role in autoimmune diseases, but its role in Graves' disease and TED is unknown. Here, we investigated whether induction of experimental Graves' disease and accompanying TED involves bone marrow activation and whether interference with IGF-1R signaling prevents this activation. Results: Immunization of mice with TSHR resulted in an increase the numbers of CD4-positive T-lymphocytes (p ≤0.0001), which was normalized by linsitinib (p = 0.0029), an increase of CD19-positive B-lymphocytes (p= 0.0018), which was unaffected by linsitinib and a decrease of GR1-positive cells (p= 0.0038), which was prevented by linsitinib (p= 0.0027). In addition, we observed an increase of Sca-1 positive hematopietic stem cells (p= 0.0007) and of stromal cell-derived factor 1 (SDF-1) (p ≤0.0001) after immunization with TSHR which was prevented by linsitinib (Sca-1: p= 0.0008, SDF-1: p ≤0.0001). TSHR-immunization also resulted in upregulation of CCL-5, IL-6 and osteopontin (all p ≤0.0001) and a concomitant decrease of the immune-inhibitory cytokines IL-10 (p= 0.0064) and PGE2 (p ≤0.0001) in the bone marrow (all p ≤ 0.0001). Treatment with the IGF-1R antagonist linsitinib blocked these events (all p ≤0.0001). We further demonstrate a down-regulation of arginase-1 expression (p= 0.0005) in the bone marrow in TSHR immunized mice, with a concomitant increase of local arginine (p ≤0.0001). Linsitinib induces an upregulation of arginase-1 resulting in low arginase levels in the bone marrow. Reconstitution of arginine in bone marrow cells in vitro prevented immune-inhibition by linsitinib. Conclusion: Collectively, these data indicate that the bone marrow is activated in experimental Graves' disease and TED, which is prevented by linsitinib. Linsitinib- mediated immune-inhibition is mediated, at least in part, by arginase-1 up-regulation, consumption of arginine and thereby immune inhibition. [ABSTRACT FROM AUTHOR]

Simple Summary: The insulin-like growth factor 1 receptor (IGF1R) is a receptor tyrosine kinase (RTK) widely expressed in many cancers, including the pediatric cancer neuroblastoma. Aberrant activation of the anaplastic lymphoma kinase (ALK) RTK by activating point mutations or amplification is identified in 5–12% of neuroblastomas. Here, we investigated IGF1R in ALK-driven neuroblastoma, with the aim of understanding its contribution and exploring its potential for targeted therapy. Using ALK-driven neuroblastoma cell lines, we show that ALK-mutated cells are more sensitive to IGF1R inhibition than ALK-amplified cells, and a synergistic effect is obtained when combining ALK and IGF1R inhibitors. Mechanistically, in ALK-mutated neuroblastoma cells, both ALK and IGF1R contribute significantly to the activation of the downstream PI3K-AKT and RAS-MAPK signaling pathways. Our results suggest that differential activation of signaling downstream of the ALK and IGF1R pathways is in part due to preferential recruitment of adaptor proteins. Aberrant activation of anaplastic lymphoma kinase (ALK) by activating point mutation or amplification drives 5–12% of neuroblastoma (NB). Previous work has identified the involvement of the insulin-like growth factor 1 receptor (IGF1R) receptor tyrosine kinase (RTK) in a wide range of cancers. We show here that many NB cell lines exhibit IGF1R activity, and that IGF1R inhibition led to decreased cell proliferation to varying degrees in ALK-driven NB cells. Furthermore, combined inhibition of ALK and IGF1R resulted in synergistic anti-proliferation effects, in particular in ALK-mutated NB cells. Mechanistically, both ALK and IGF1R contribute significantly to the activation of downstream PI3K-AKT and RAS-MAPK signaling pathways in ALK-mutated NB cells. However, these two RTKs employ a differential repertoire of adaptor proteins to mediate downstream signaling effects. We show here that ALK signaling led to activation of the RAS-MAPK pathway by preferentially phosphorylating the adaptor proteins GAB1, GAB2, and FRS2, while IGF1R signaling preferentially phosphorylated IRS2, promoting activation of the PI3K-AKT pathway. Together, these findings reveal a potentially important role of the IGF1R RTK in ALK-mutated NB and that co-targeting of ALK and IGF1R may be advantageous in clinical treatment of ALK-mutated NB patients. [ABSTRACT FROM AUTHOR]

Introduction: Graves' disease (GD) is an autoimmune disorder caused by autoantibodies against the thyroid stimulating hormone receptor (TSHR) leading to overstimulation of the thyroid gland. Thyroid eye disease (TED) is the most common extra thyroidal manifestation of GD. Therapeutic options to treat TED are very limited and novel treatments need to be developed. In the present study we investigated the effect of linsitinib, a dual small-molecule kinase inhibitor of the insulin-like growth factor 1 receptor (IGF-1R) and the Insulin receptor (IR) on the disease outcome of GD and TED. Methods: Linsitinib was administered orally for four weeks with therapy initiating in either the early ("active") or the late ("chronic") phases of the disease. In the thyroid and the orbit, autoimmune hyperthyroidism and orbitopathy were analyzed serologically (total anti-TSHR binding antibodies, stimulating anti TSHR antibodies, total T4 levels), immunohistochemically (H&E-, CD3-, TNFaand Sirius red staining) and with immunofluorescence (F4/80 staining). An MRI was performed to quantify in vivo tissue remodeling inside the orbit. Results: Linsitinib prevented autoimmune hyperthyroidism in the early state of the disease, by reducing morphological changes indicative for hyperthyroidism and blocking T-cell infiltration, visualized by CD3 staining. In the late state of the disease linsitinib had its main effect in the orbit. Linsitinib reduced immune infiltration of T-cells (CD3 staining) and macrophages (F4/80 and TNFa staining) in the orbita in experimental GD suggesting an additional, direct effect of linsitinib on the autoimmune response. In addition, treatment with linsitinib normalized the amount of brown adipose tissue in both the early and late group. An in vivo MRI of the late group was performed and revealed a marked decrease of inflammation, visualized by 19F MR imaging, significant reduction of existing muscle edema and formation of brown adipose tissue. Conclusion: Here, we demonstrate that linsitinib effectively prevents development and progression of thyroid eye disease in an experimental murine model for Graves' disease. Linsitinib improved the total disease outcome, indicating the clinical significance of the findings and providing a path to therapeutic intervention of Graves' Disease. Our data support the use of linsitinib as a novel treatment for thyroid eye disease. [ABSTRACT FROM AUTHOR]

IntroductionGraves’ disease is an autoimmune disorder caused by auto-antibodies against the thyroid stimulating hormone receptor (TSHR). Overstimulation of the TSHR induces hyperthyroidism and thyroid eye disease (TED) as the most common extra thyroidal manifestation of Graves’ disease. In TED, the TSHR cross talks with the insulin-like growth factor 1 receptor (IGF-1R) in orbital fibroblasts leading to inflammation, deposition of hyaluronan and adipogenesis. The bone marrow may play an important role in autoimmune diseases, but its role in Graves’ disease and TED is unknown. Here, we investigated whether induction of experimental Graves’ disease and accompanying TED involves bone marrow activation and whether interference with IGF-1R signaling prevents this activation.ResultsImmunization of mice with TSHR resulted in an increase the numbers of CD4-positive T-lymphocytes (p ≤0.0001), which was normalized by linsitinib (p = 0.0029), an increase of CD19-positive B-lymphocytes (p= 0.0018), which was unaffected by linsitinib and a decrease of GR1-positive cells (p= 0.0038), which was prevented by linsitinib (p= 0.0027). In addition, we observed an increase of Sca-1 positive hematopietic stem cells (p= 0.0007) and of stromal cell-derived factor 1 (SDF-1) (p ≤0.0001) after immunization with TSHR which was prevented by linsitinib (Sca-1: p= 0.0008, SDF-1: p ≤0.0001). TSHR-immunization also resulted in upregulation of CCL-5, IL-6 and osteopontin (all p ≤0.0001) and a concomitant decrease of the immune-inhibitory cytokines IL-10 (p= 0.0064) and PGE2 (p ≤0.0001) in the bone marrow (all p≤ 0.0001). Treatment with the IGF-1R antagonist linsitinib blocked these events (all p ≤0.0001). We further demonstrate a down-regulation of arginase-1 expression (p= 0.0005) in the bone marrow in TSHR immunized mice, with a concomitant increase of local arginine (p ≤0.0001). Linsitinib induces an upregulation of arginase-1 resulting in low arginase levels in the bone marrow. Reconstitution of arginine in bone marrow cells in vitro prevented immune-inhibition by linsitinib.ConclusionCollectively, these data indicate that the bone marrow is activated in experimental Graves’ disease and TED, which is prevented by linsitinib. Linsitinib-mediated immune-inhibition is mediated, at least in part, by arginase-1 up-regulation, consumption of arginine and thereby immune inhibition.

IntroductionGraves’ disease (GD) is an autoimmune disorder caused by autoantibodies against the thyroid stimulating hormone receptor (TSHR) leading to overstimulation of the thyroid gland. Thyroid eye disease (TED) is the most common extra thyroidal manifestation of GD. Therapeutic options to treat TED are very limited and novel treatments need to be developed. In the present study we investigated the effect of linsitinib, a dual small-molecule kinase inhibitor of the insulin-like growth factor 1 receptor (IGF-1R) and the Insulin receptor (IR) on the disease outcome of GD and TED.MethodsLinsitinib was administered orally for four weeks with therapy initiating in either the early (“active”) or the late (“chronic”) phases of the disease. In the thyroid and the orbit, autoimmune hyperthyroidism and orbitopathy were analyzed serologically (total anti-TSHR binding antibodies, stimulating anti TSHR antibodies, total T4 levels), immunohistochemically (H&E-, CD3-, TNFa- and Sirius red staining) and with immunofluorescence (F4/80 staining). An MRI was performed to quantify in vivo tissue remodeling inside the orbit.ResultsLinsitinib prevented autoimmune hyperthyroidism in the early state of the disease, by reducing morphological changes indicative for hyperthyroidism and blocking T-cell infiltration, visualized by CD3 staining. In the late state of the disease linsitinib had its main effect in the orbit. Linsitinib reduced immune infiltration of T-cells (CD3 staining) and macrophages (F4/80 and TNFa staining) in the orbita in experimental GD suggesting an additional, direct effect of linsitinib on the autoimmune response. In addition, treatment with linsitinib normalized the amount of brown adipose tissue in both the early and late group. An in vivo MRI of the late group was performed and revealed a marked decrease of inflammation, visualized by 19F MR imaging, significant reduction of existing muscle edema and formation of brown adipose tissue.ConclusionHere, we demonstrate that linsitinib effectively prevents development and progression of thyroid eye disease in an experimental murine model for Graves’ disease. Linsitinib improved the total disease outcome, indicating the clinical significance of the findings and providing a path to therapeutic intervention of Graves’ Disease. Our data support the use of linsitinib as a novel treatment for thyroid eye disease.

Background: Thyrotropin receptor (TSHR) and insulin-like growth factor 1 receptor (IGF-1R) have been shown to crosstalk in primary cultures of human thyrocytes (hThyros) and Graves' orbital fibroblasts. The phenomenon of TSHR/IGF-1R crosstalk has been largely studied in the pathogenesis of thyroid eye disease (TED) in human orbital fibroblasts. Here, we investigated the effects of inhibiting the IGF-1R-mediated contribution to crosstalk by linsitinib (Lins), a small-molecule IGF-1R kinase inhibitor, on TSH-induced regulation of thyroperoxidase (TPO) and thyroglobulin (TG) mRNAs and proteins in hThyros in vitro, and on TPO and TG mRNAs and free thyroxine (fT4) levels in vivo in mice. Methods: Steady-state levels of mRNAs of TPO and TG in hThyros in vitro and mouse thyroid glands were measured by RT-qPCR. Human TG (hTG) and human TPO (hTPO) proteins in human thyroid cell cultures were measured by Western blot or ELISA. Translation rates of hTG were quantified by stable isotope labeling by amino acids method (SILAC). Thyroidal mouse Tpo (m Tpo ) and Tg (m Tg ) mRNAs and fT4 in mice were assessed after Lins administration on 3 consecutive days followed by an intraperitoneal dose of bovine TSH (bTSH) 3 hours prior to drawing blood. Results: In primary cultures of hThyros, Lins inhibited bTSH-induced upregulation of hTPO mRNA by 61.5%, and hTPO protein was inhibited by 42.4%. There was no effect of Lins on hTG mRNA, but Lins inhibited the upregulation of secreted and cell-associated hTG protein by 50.1% and 42.2%, respectively, by inhibiting hTG mRNA translation. m Tpo mRNA measured in thyroid glands after treatment with Lins was reduced by 31.5%. There was no effect of Lins on m Tg mRNA, however, Lins decreased fT4 levels in mice under basal (endogenous mTSH levels) and bTSH-treated conditions. Conclusions: The IGF-1R antagonist Lins inhibited bTSH-stimulated hTG and hTPO protein expression in primary cultures of hThyros and fT4 levels in mice. We suggest that thyroid function studies be monitored when Lins is administered to humans, for example, if it is used to treat TED.

The individual cascades of the insulin-like growth factor-1 (IGF-1) signaling pathway and the molecular mechanism of aging have not been fully clarified. In the current study, we explored the effect of DNA polymerase delta 1 (POLD1) on the IGF-1 signaling pathway in cell aging. First, we analyzed the relationship between IGF-1 and POLD1 expression in aging. To investigate the effect of IGF-1 on POLD1 expression and aging, the 2BS cells were incubated with young-age or old-age human serum, IGF-1 protein, or linsitinib. Next, the effect of IGF-1 on aging was examined in the 2BS cells with increased or decreased POLD1 expression to clarify the molecular mechanism. In this study, we found that IGF-1 expression increased and POLD1 expression decreased with aging in human serum and hippocampal tissues of SAMP8 mice, and a negative relationship between IGF-1 and POLD1 expression was observed. Furthermore, the cells cultured with old-age human serum or IGF-1 showed lower POLD1 expression and more pronounced senescence characteristics, and the effect could be reversed by treatment with linsitinib or overexpression of POLD1, while the effect of linsitinib on cell aging could be reversed with the knockdown of POLD1. Taken collectively, our findings demonstrate that IGF-1 promotes aging by binding to IGF-1R and inhibiting the expression of POLD1. These findings offer a new target for anti-aging strategies. [ABSTRACT FROM AUTHOR]

Both the epidermal growth factor receptor (EGFR) and insulin-like growth factor 1 receptor (IGF-1R) have been implicated in the development of cancers, and the increased expression of both receptors has been observed in esophageal cancer. However, the tyrosine kinase inhibitors of both receptors have thus far failed to provide clinical benefits for esophageal cancer patients. Studies have confirmed the complicated crosstalks that exist between the EGFR and IGF-1R pathways. The EGFR and IGF-1R signals act as mutual compensation pathways, thereby conveying resistance to EGFR or IGF-1R inhibitors when used alone. This study evaluated the antitumor efficacy of the EGFR/HER2 inhibitors, gefitinib and lapatinib, in combination with the IGF-1R inhibitor, linsitinib, on the esophageal squamous cell carcinoma (ESCC). Gefitinib or lapatinib, in combination with linsitinib, synergistically inhibited the proliferation, migration, and invasion of ESCC cells, caused significant cell cycle arrest, and induced marked cell apoptosis. Their combination demonstrated stronger inhibition on the activation of EGFR, HER2, and IGF-1R as well as the downstream signaling molecules. In vivo, the addition of linsitinib to gefitinib or lapatinib also potentiated the inhibition effects on the growth of xenografts. Our results suggest the next clinical exploration of the combination of gefitinib or lapatinib with linsitinib in the treatment of ESCC patients. [ABSTRACT FROM AUTHOR]

Gliomas are the most frequent solid tumors in children. Among these, high-grade gliomas are less common in children than in adults, though they are similar in their aggressive clinical behavior. In adults, glioblastoma is the most lethal tumor of the central nervous system. Insulin-like growth factor 1 receptor (IGF1R) plays an important role in cancer biology, and its nuclear localization has been described as an adverse prognostic factor in different tumors. Previously, we have demonstrated that, in pediatric gliomas, IGF1R nuclear localization is significantly associated with high-grade tumors, worst clinical outcome, and increased risk of death. Herein we explore the role of IGF1R intracellular localization by comparing two glioblastoma cell lines that differ only in their IGF1R capacity to translocate to the nucleus. In vitro , IGF1R nuclear localization enhances glioblastoma cell motility and metabolism without affecting their proliferation. In vivo , IGF1R has the capacity to translocate to the nucleus and allows not only a higher proliferation rate and the earlier development of tumors but also renders the cells sensitive to OSI906 therapy. With this work, we provide evidence supporting the implications of the presence of IGF1R in the nucleus of glioma cells and a potential therapeutic opportunity for patients harboring gliomas with IGF1R nuclear localization. [ABSTRACT FROM AUTHOR]

Gliomas are the most frequent solid tumors in children. Among these, high-grade gliomas are less common in children than in adults, though they are similar in their aggressive clinical behavior. In adults, glioblastoma is the most lethal tumor of the central nervous system. Insulin-like growth factor 1 receptor (IGF1R) plays an important role in cancer biology, and its nuclear localization has been described as an adverse prognostic factor in different tumors. Previously, we have demonstrated that, in pediatric gliomas, IGF1R nuclear localization is significantly associated with high-grade tumors, worst clinical outcome, and increased risk of death. Herein we explore the role of IGF1R intracellular localization by comparing two glioblastoma cell lines that differ only in their IGF1R capacity to translocate to the nucleus. In vitro, IGF1R nuclear localization enhances glioblastoma cell motility and metabolism without affecting their proliferation. In vivo, IGF1R has the capacity to translocate to the nucleus and allows not only a higher proliferation rate and the earlier development of tumors but also renders the cells sensitive to OSI906 therapy. With this work, we provide evidence supporting the implications of the presence of IGF1R in the nucleus of glioma cells and a potential therapeutic opportunity for patients harboring gliomas with IGF1R nuclear localization.