Insulin-like Growth Factor Binding Protein-3 Expression Research Articles

Abstract A014: Mitochondrial dynamics in insulin-like growth factor binding protein 3-mediated radiosensitivity of oral squamous cell carcinoma cells

Abstract Radiation therapy, a common adjuvant therapy for oral squamous cell carcinoma (OSCC) patients either received operation or not, efficiently reduces the tumor infiltration area and growth. Insulin-like growth factor binding protein 3 (IGFBP3) is a member of a secretary glycoprotein family. We previously found that IGFBP3 promotes cell migration and lymph node metastasis of OSCC cells. However, OSCC patients with high IGFBP3 expression had a better prognostic outcome than those with low IGFBP3 expression. Moreover, we verified that ectopic expression of IGFBP3 augmented the radiosensitivity, while IGFBP3 knockdown diminished the radio-resistance of OSCC cells. We observed changes in mitochondrial morphology in IGFBP3-expressing OSCC cells after ionizing radiation (IR) treatment; however, the roles of IGFBP3 in mitochondrial dynamics remain unclear. The analyses of cell survival, reactive oxygen species production, and loss of mitochondrial membrane potential were used to verify the IGFBP3-mediated radiosensitivity. Using mitochondria by 3D cell explorer and quantification of mitochondria dynamics by immunofluorescence staining, the fission and fusion mitochondria in irradiated IGFBP3-expressing cells and IGFBP3 knockdown cells were increased, respectively. By western blot, we found phosphorylated dynamin-related protein 1 (DRP1) positively associated with IGFBP3 levels in irradiated cells. By transiently expressing DRP1 in IGFBP3-expressing cells, we found that IGFBP3-mediated radiosensitivity and mitochondrial fission were flattened by DRP1 inhibition, suggesting the role of DRP1 in IGFBP3-mediated mitochondrial fission. Our study is to elucidate the mechanism of IGFBP3-mediated radiosensitivity and hope to provide different strategies to sensitize radiotherapy and enhance the synergy between radiotherapy and immunotherapy. Citation Format: Ya-Wen Chen. Mitochondrial dynamics in insulin-like growth factor binding protein 3-mediated radiosensitivity of oral squamous cell carcinoma cells. [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Targeted Therapies in Combination with Radiotherapy; 2025 Jan 26-29; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(2_Suppl):Abstract nr A014

Ablation of IGFBP5 expression alleviates neurogenic erectile dysfunction by inducing neurovascular regeneration.

To investigate the therapeutic potential of eliminating insulin-like growth factor-binding protein 5 (IGFBP5) expression in improving erectile function in mice with cavernous nerve injury (CNI)-induced erectile dysfunction (ED). Eight-week-old male C57BL/6 mice were divided into four groups: a sham-operated group and three CNI-induced ED groups. The CNI-induced ED groups were treated with intracavernous injections 3 days before the CNI procedure. These injections included phosphate-buffered saline, scrambled control short hairpin RNA (shRNA), or shRNA targeting mouse IGFBP5 lentiviral particles. One week after CNI, erectile function was evaluated and the penile tissue was then harvested for histological examination and western blot analysis. Additionally, the major pelvic ganglia (MPG) and dorsal root ganglia (DRG) were cultured for ex vivo neurite outgrowth assays. Following CNI, IGFBP5 expression in the cavernous tissues significantly increased, reaching its peak at day 7. First, ablation of IGFBP5 expression promotes neurite sprouting in MPG and DRG when exposed to lipopolysaccharide. Second, ablating IGFBP5 expression in CNI-induced ED mice improved erectile function, likely owing to increased neurovascular contents, including endothelial cells, pericytes, and neuronal processes. Third, ablating IGFBP5 expression in CNI-induced ED mice promoted neurovascular regeneration by increasing cell proliferation, reducing apoptosis, and decreasing Reactive oxygen species production. Finally, western blot analysis demonstrated that IGFBP5 ablation attenuated the JNK/c-Jun signaling pathway, activated the PI3K/AKT signaling pathway, and increased vascular endothelial growth factor and neurotrophic factor expression. Ablating IGFBP5 expression enhanced neurovascular regeneration and ultimately improved erectile function in CNI-induced ED mice.

IGFBP5 affects cardiomyocyte survival and functional recovery in mice following myocardial ischemia

Insulin-like growth factor-binding protein 5 (IGFBP5) has been shown to be useful for the diagnosis and treatment of multiple tumors and cerebrovascular diseases. However, it is unknown whether IGFBP5 is involved in myocardial repair following myocardial infarction (MI). Here we show high expression of IGFBP5 in multiple models of ischemic and hypoxic injury. IGFBP5 affected the proliferation of neonatal rat cardiomyocytes (NRCMs) and the cardiomyocyte apoptosis induced by oxygen-glucose deprivation (OGD). Subsequently, heart-specific IGFBP5 knockdown inhibited myocardial apoptosis and increased cardiomyocyte proliferation in mice with MI. During the chronic remodeling stage, heart-specific regulation of IGFBP5 ameliorated pathological cardiac remodeling and dysfunction. Mechanistically, IGFBP5 regulated cardiomyocyte survival through the insulin-like growth factor 1 (IGF1) receptor (IGF1R)/protein kinase B (PKB/AKT) pathway. In summary, our results provide mechanistic insights into the effect of IGFBP5 on cardiomyocyte during cardiac repair. IGFBP5 may represent a therapeutic target for myocardial ischemic injury.

Insulin-like growth factor-binding protein-3 is induced by tamoxifen and fulvestrant and modulates fulvestrant response in breast cancer cells.

Insulin-like growth factor binding protein-3 (IGFBP-3) exerts varying effects on estrogen receptor alpha (ERα)-positive and triple-negative breast cancer (TNBC) cells. In ERα-positive cells, IGFBP-3 is antiproliferative and proapoptotic. In contrast, IGFBP-3 stimulates proliferation in triple-negative breast cancer (TNBC) cells via EGFR activation. To identify potential mechanisms that underlie the opposing effects of IGFBP-3 on these two breast cancer subtypes, IGFBP-3 expression was determined in cell line models of both ERα-positive breast cancer and TNBC, and cells were treated with antiestrogens tamoxifen and fulvestrant. MCF-7 and T-47D cells expressed low levels of IGFBP-3 when compared to MDA-MB-231 and MDA-MB-468 cells. MCF-7 cells with acquired resistance to the selective estrogen receptor degrader fulvestrant expressed high IGFBP-3 and MCF-7 cells with constitutive IGFBP-3 expression were fulvestrant resistant. IGFBP-3 expression was increased in all cell lines upon treatment with fulvestrant or the selective estrogen receptor modulator tamoxifen and both fulvestrant and tamoxifen increased TNBC cell proliferation. Further, IGFBP-3 expression was increased by treatment with the GPER1 agonist G-1 and attenuated upon treatment with P17, a YAP/TAZ inhibitor. These data suggest that IGFBP-3 modulates breast cancer cells and is a mediator of breast cancer cell response to fulvestrant and tamoxifen.

Characterization of a novel IGFBP-2 transcript in the ovarian granulosa cells of chicken follicles: mRNA expression, function and effect of reproductive hormones and IGF1

Insulin-like growth factor binding protein-2 (IGFBP-2), a binding protein of insulin-like growth factor (IGF) system, regulates the activity of IGFs and also influences cellular function with endogenous activity. In mammals, IGFBP-2 is reported to affect ovarian follicle development and steroidogenesis; however, its role in the chicken ovary is unknown. In this study, we investigated the mRNA expression and function of a novel IGFBP-2 transcript and the effect of reproductive hormones and insulin-like growth factor 1 (IGF1) on its expression in the ovarian granulosa cells of chicken follicles. The mRNA expression of IGFBP-2 was significantly increased in granulosa cells after follicle selection and was higher in hierarchical granulosa cells (Post-GCs) than in pre-hierarchical granulosa cells (Pre-GCs). IGFBP-2 promoted the proliferation and inhibited the apoptosis of both Pre-GCs and Post-GCs, enhanced the mRNA expression of genes involved in progesterone (P4) synthesis in Pre-GCs. However, in Post-GCs, IGFBP-2 inhibited the mRNA expression of these genes and suppressed P4 secretion. The mRNA expression of IGFBP-2 was inhibited by estradiol (E2) and follicle-stimulating hormone (FSH), but enhanced by P4 in Pre-GCs. In Post-GCs, FSH and IGF1 stimulated the mRNA expression of IGFBP-2 synergistically. Knockdown of IGFBP-2 attenuated the stimulatory effect of IGF1 on the mRNA expression of the side chain cleavage enzyme cytochrome P450 family 11 subfamily A member 1 (CYP11A1). These findings indicate that IGFBP-2 is regulated by FSH and IGF1, exerts different functions in Pre-GCs and Post-GCs in regulating IGF1 and plays an important role in chicken follicle development by affecting granulosa cell proliferation and P4 synthesis.

High androgen level during controlled ovarian stimulation cycle impairs endometrial receptivity in PCOS patients

PCOS is one of the most common endocrine disorders among women of reproductive age. While the mechanism involved is not yet fully characterized. Our study aims to examine the pregnancy outcomes of embryo transfers in women with PCOS after pretreatment, and to explore the possible effect of high androgen levels on endometrial receptivity. Retrospective cohort study was conducted to analyze pregnancy outcomes among 2714 infertile women with tubal factor and 452 PCOS women. Endometrium samples were collected from 6 controls and 6 PCOS patients to detect the expression of endometrial receptivity marks. The implantation rate, clinical and ongoing pregnancy rates and live birth rate in women with PCOS followed fresh embryo transfers were obviously decreased even after the pretreatment. Similar pregnancy outcomes were found in frozen-thawed embryo transfer cycles between women with or without PCOS. Strikingly, serum total testosterone (TT) levels on trigger day were significantly higher in PCOS women. Women with high TT levels presented significantly lower clinical and ongoing pregnancy rates, and the expression of insulin-like growth factor binding protein 1 (IGFBP-1), and leukemia inhibitory factor (LIF) in the endometria decreased significantly as well. High doses of testosterone significantly down-regulated the expression of IGFBP-1 and LIF in Ishikawa cells. Although endocrine abnormalities had been improved before the controlled ovarian stimulation (COS) cycle started, higher serum TT levels were detected on the trigger day of the COS cycle in PCOS patients, which may contribute to the decreased fresh embryo implantation by impairing endometrial receptivity.

The inhibitory effect of type V transforming growth factor-β receptor antagonist on the proliferation of keloid fibroblasts by suppressing insulin-like growth factor-binding protein 3-interleukin-6 signaling

Abstract Background: Hyperplasia of fibroblasts is critical in keloid pathogenesis. Insulin-like growth factor-binding protein 3 (IGFBP3) is an important factor in the regulation of cell growth and type V transforming growth factor-β receptor (TβR-V) is a specific receptor of IGFBP3. However, the role of IGFBP3 in keloid development has not been reported. Objectives: This study aimed to investigate the role of IGFBP3 in keloid pathogenesis and evaluate the effects of TβR-V antagonist on keloid fibroblasts (KFs) activities. Methods: IGFBP3 expression in keloids and its impact on KF proliferation were examined. The effects of TβR-V antagonist on KF cell proliferation, migration, and invasion were also investigated. Differentially expressed genes (DEGs) between TβR-V antagonist treated and nontreated KFs were identified through RNA-sequencing (RNA-seq), followed by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein–protein interaction (PPI) network analyses. Results: IGFBP3 was overexpressed in keloids and could promote KF proliferation. TβR-V antagonist suppressed KFs proliferation, migration, and invasion. GO and KEGG analyses showed that the downregulated DEGs revealed by RNA-seq were significantly enriched in terms related to cell proliferation. Interleukin-6 (IL-6) was identified as the only gene interacting with IGFBP3 in the PPI network and was associated with nine hub genes. In vitro assay confirmed the suppression of IL-6 by TβR-V antagonist in KFs. Conclusion: Our study demonstrated that TβR-V antagonist could inhibit keloid growth likely through suppressing IGFBP3-IL-6 signaling activation. These findings suggest that targeting TβR-V could be a potential therapeutic strategy for keloid treatment.

Insulin-like growth factor-binding protein 7 exacerbates inflammatory response and lipid metabolism imbalance in alcohol-associated liver disease

Alcohol-associated liver disease(ALD), caused by excessive alcohol consumption, are often associated with inflammatory outbreaks and lipid deposition in the liver. The role of Insulin-like growth factor-binding protein 7 (IGFBP7), an important metabolic regulator, in ALD, its underlying regulatory mechanism, and its potential implication in anti-ALD therapies remain unknown.We investigated the effects of IGFBP7 on hepatic inflammation and lipid metabolism disruption in a mouse model of ALD. Mice were fed by chronic ethanol feeding plus a single binge of ethanol feeding(chronic-plus-single-binge model). In addition, ethanol exposure modeling studies were performed on cultured hepatocytes to verify molecular correlations.The results showed that IGFBP7 expression was significantly elevated in the livers of mice and hepatocytes after chronic ethanol exposure. Subsequently, the results of a study by specific knockout of IGFBP7(IGFBP7-cKO) in mouse hepatocytes and lentiviral silencing of IGFBP7 in vivo suggested that IGFBP7 deletion could improve liver function levels in alcohol-fed mice; It also attenuated the outbreak of hepatitis factor and the disorder of lipid metabolism in mice.Using RNA-seq sequencing of mouse liver tissue, we found that IGFBP7 affects several downstream metabolic signaling pathways, including PPAR, MAPK, FoxO, etc. Then, we used the PPARα plasmid in hepatocytes and discovered that overexpressing PPARα reversed the impact of IGFBP7 on lipid metabolism disorders in hepatocytes.In conclusion, IGFBP7 deficiency in alcohol-associated liver disease alleviates the decline in liver function and the imbalance of lipid metabolism in mice, attenuates the inflammatory outbreak, and affects a variety of downstream lipid metabolism factors by regulating PPARα. Hence, IGFBP7 may be an effective therapeutic target in the treatment of ALD.

IGFBP2 functions as an endogenous protector against hepatic steatosis via suppression of the EGFR-STAT3 pathway

ObjectiveNon-alcoholic fatty liver disease (NAFLD) is deemed as an emerging global epidemic, whereas the underlying pathogenic mechanism remains to be clarified. We aimed to systemically analyze all the NAFLD-related gene expression datasets from published human-based studies, by which exploring potential key factors and mechanisms accounting for the pathogenesis of NAFLD. MethodsRobust rank aggregation (RRA) method was used to integrate NAFLD-related gene expression datasets. For fatty liver study, adeno-associated virus (AAV) delivery and genetic knockout mice were used to create IGFBP2 (Insulin-like growth factor binding protein 2) gain- or loss-of function models. Western blot, Co-immunoprecipitation (Co-IP), immunofluorescent (IF) staining, luciferase assay, molecular docking simulation were performed to reveal the IGFBP2-EGFR-STAT3 axis involved. Key axis protein levels in livers from healthy donors and patients with NAFLD were assessed via immunohistochemical staining. ResultsBy using RRA method, the present study identified IGFBP2 being the most significantly down-regulated gene in all NAFLD subjects. The decreased IGFBP2 expression was further confirmed in the liver tissues from patients and animal models of NAFLD. IGFBP2 deficiency aggravated hepatic steatosis and NASH phenotypes and promoted lipogenic gene expression both in vivo and in vitro. Mechanistically, IGFBP2 directly binds to and regulates EGFR, whereas blockage of the IGFBP2-EGFR complex by knockdown of IGFBP2 resulted in the EGFR-STAT3 pathway activation, which in turn promoted the promoter activity of Srebf1. By using molecular docking simulation and protein-protein interaction analysis, the sequence of 233-257 amino acids in IGFBP2 was characterized as a key motif responding for its specific binding to EGFR and the protective effect against hepatic steatosis. ConclusionsThe current study has, for the first time, identified IGFBP2 as a novel protector against hepatosteatosis. The protective effect is mediated by its specific interaction with EGFR and thereby suppressing the EGFR-STAT3 pathway. Therefore, pharmaceutically targeting the IGFBP2-EGFR-STAT3 axis may provide a theoretical basis for for the treatment of NAFLD/NASH and the associated diseases.

IGFBP7 promotes the proliferation and differentiation of primary myoblasts and intramuscular preadipocytes in chicken

Though it is well known that insulin-like growth factor (IGF) binding protein 7 (IGFBP7) plays an important role in myogenesis and adipogenesis in mammals, its impact on the proliferation, differentiation, and lipid deposition in chicken primary myoblasts (CPM) and intramuscular preadipocytes remains unexplored. In the present study, we firstly examined the correlation between SNPs within the genomic sequence of the IGFBP7 gene and carcass and blood chemical traits in a F2 resource population by genetic association analysis, and found that a significant correlation between the SNP (4_49499525) located in the intron region of IGFBP7 and serum high-density lipoproteins (HDL). We then examined the expression patterns of IGFBP7 across different stages of proliferation and differentiation in CPMs and intramuscular preadipocytes via qPCR, and explored the biological functions of IGFBP7 through gain- and loss-of-function experiments and a range of techniques including qPCR, CCK-8, EdU, flow cytometry, Western blot, immunofluorescence, and Oil Red O staining to detect the proliferation, differentiation, and lipid deposition in CPMs and intramuscular preadipocytes. We ascertained that the expression levels of the IGFBP7 gene increased as cell differentiation progresses in CPMs and intramuscular preadipocytes, and that IGFBP7 promotes the proliferation and differentiation of these cells, as well as facilitates intracellular lipid deposition. Furthermore, we investigated the regulatory mechanism of IGFBP7 expression by using co-transfection strategy and dual-luciferase reporter assay, and discovered that the myogenic transcription factors (MRF), myoblast determination factor (MyoD) and myogenin (MyoG), along with the adipocyte-specific transcription factor (TF) CCAAT/enhancer-binding protein α (C/EBPα), can bind to the core transcription activation region of the IGFBP7 promoter located 500 bp upstream from the transcription start site, thereby promoting IGFBP7 transcription and expression. Taken together, our study underscores the role of IGFBP7 as a positive regulator for myogenesis and adipogenesis, while also elucidating the functional and transcriptional regulatory mechanisms of IGFBP7 in chicken skeletal muscle development and intramuscular adipogenesis.

SVIP reduces IGFBP-2 expression and inhibits glioblastoma progression via stabilizing PTEN

Glioblastoma (GBM) presents significant challenges due to its invasive nature and genetic heterogeneity. In this study, we investigated the impact of Small VCP/P97-Interacting Protein (SVIP) on GBM progression. Our results revealed elevated expression of Insulin-like Growth Factor Binding Protein 2 (IGFBP-2) and STIP1 homology and U-box containing protein 1 (STUB1), coupled with reduced SVIP levels in GBM samples. Notably, high IGFBP-2 expression correlated with poor prognosis. Mechanistically, SVIP competitively inhibited STUB1, selectively binding to VCP/p97, thereby reducing PTEN degradation. This SVIP-mediated regulation exerted influence on the PTEN/PI3K/AKT/mTOR pathway, leading to the suppression of GBM progression. Co-localization experiments demonstrated that SVIP hindered PTEN ubiquitination and degradation by outcompeting STUB1 for VCP/p97 binding. Moreover, SVIP overexpression resulted in reduced activation of AKT/mTOR signaling and facilitated autophagy. In vivo experiments using a GBM xenograft model substantiated the tumor-suppressive effects of SVIP, evident by suppressed tumor growth, decreased IGFBP-2 expression, and improved survival rates. Collectively, our findings underscore the functional significance of SVIP in GBM progression. By inhibiting STUB1 and stabilizing PTEN, SVIP modulates the expression of IGFBP-2 and attenuates the activation of the PI3K/AKT/mTOR pathway, thereby emerging as a promising therapeutic target for GBM treatment.

Expression of insulin-like growth factor binding protein 5 in the vaginal wall tissues of older women with pelvic organ prolapse

This study aimed to investigate the expression and significance of insulin-like growth factor binding protein 5 (IGFBP5) and extracellular matrix (ECM) related proteins in anterior vaginal wall tissues among aged pelvic organ prolapse (POP) patients. Tissues from the anterior vaginal wall were collected from 28 patients with POP and 20 patients without POP. The expression of protein and mRNA levels of IGFBP5 and ECM related proteins were evaluated in the vaginal wall tissues using immunohistochemistry, western blotting, and RT-qPCR techniques. The expression levels were then compared with clinical parameters. The expression levels of protein and mRNA of IGFBP5, collagen I, and collagen III were significantly lower in the POP group. Protein and mRNA expression levels of MMP2 were significantly higher in the POP group. IGFBP5 protein and mRNA expression levels were negatively correlated with age and significantly lower in older POP patients (≥ 65 years old) compared to younger POP patients (< 65 years old). IGFBP5 protein and mRNA expression levels were also significantly lower in POP-Q stage IV patients compared to POP-Q stage III patients. IGFBP5 expression level is negatively correlated with the age and severity of prolapse. The significant decrease in IGFBP5 expression may play a crucial part in the aging process and the occurrence of POP.

Dynamic changes in insulin-like growth factor binding protein expression occur between embryonic and early post-hatch development in broiler chickens

Somatotropic gene expression has been altered by genetic selection, and developmental changes in insulin-like growth factor (IGF) and IGF binding protein (IGFBP) expression may contribute to rapid growth and muscle accretion in commercial broilers. The objective of this study was to evaluate changes in somatotropic axis activity between embryonic day (e) 12 and post-hatch day (d) 21. Liver and breast muscle (pectoralis major) were collected to measure gene expression, and blood was collected post-hatch to measure circulating IGFs. Liver IGF1 rose rapidly post-hatch and, in muscle, IGF1 exhibited a dynamic expression pattern. Levels decreased from e14 to e20, returned to e14 levels at d3, decreased again at d10, and stayed low thereafter. In both tissues, mRNA levels of several IGFBPs changed between embryogenesis and post-hatch. Liver IGFBP2 increased between e12 and e20, returned to e12 levels on d1, and remained low. Conversely, liver IGFBP4 expression was greater post-hatch than during embryogenesis. Expression of select IGFBPs was depressed in liver during the peri-hatch period. Liver IGFBP1, IGFBP3, IGFBP5, and IGFBP7 mRNA levels all decreased around this time and returned to embryonic levels by d3. In breast muscle, expression of both IGFBP2 and IGFBP4 was reduced after hatch. Circulating insulin-like growth factor IGF1 and IGF2 levels did not change between hatch and d21. These data suggest that post-hatch IGF effects are likely modulated by target tissue IGFR1 and IGFBP expression rather than changes in circulating hormone levels, with promotion or restriction of IGF-receptor binding regulating growth. Downregulation of several IGFBPs synthesized in the liver may facilitate the metabolic transition from utilizing yolk lipids to dietary carbohydrates. Several IGFBPs produced in breast muscle appear to have growth-promotive effects during embryogenesis but restrict growth of this tissue after hatch, as their post-hatch downregulation could facilitate local IGF signaling. These developmental gene expression patterns suggest that somatotropic hormonal signaling regulating growth and muscle accretion might be controlled through differential actions of IGFBPs and provide a basis for future functional studies.

IGFBP7 mediates oxLDL-induced human vascular endothelial cell injury by suppressing the expression of SIRT1

Endothelial cell injury plays an important role in initiating atherosclerotic lesion formation. Insulin-like growth factor binding protein 7 (IGFBP7) is known to modulate the behaviors of tumor-associated endothelial cells. This study was conducted to test whether IGFBP7 is involved in endothelial cell injury during atherosclerosis. Oxidized low-density lipoprotein (oxLDL) treatment was used to mimic atherosclerosis-related endothelial cell apoptosis and inflammation response. Small interfering RNA (siRNA) technology was employed to deplete IGFBP7 expression in human aortic endothelial cells (HAECs). HAECs were exposed to recombinant human IGFBP7 protein to evaluate the function of IGFBP7. Notably, IGFBP7 expression in HAECs was induced by oxLDL treatment. Knockdown of IGFBP7 or treatment with anti-IGFBP7 abolished oxLDL-induced apoptosis and inflammation in HAECs. Moreover, recombinant IGFBP7 (40 ng/mL but not 25 ng/mL) promoted apoptosis and inflammation in HAECs. IGFBP7 co-localized with CD93 on the surface of HAECs. A mechanistic investigation uncovered that IGFBP7 induced endothelial cell injury through interaction with CD93 and reduction of SIRT1 expression via an autocrine manner. Overexpression of SIRT1 rescued IGFBP7-induced phenotype in HAECs. Taken together, IGFBP7 is induced by oxLDL and mediates oxLDL-induced endothelial cell apoptosis and inflammation, likely through downregulation of SIRT1. These observations support a rationale to prevent atherosclerosis by targeting IGFBP7 activity.

P-411 CD55 deficiency hinders decidualization in unexplained early miscarriage through the Src/ERK signaling pathway

Abstract Study question What is the role of CD55 in the process of human endometrial stromal cells (HESCs) decidualization in unexplained early miscarriage? Summary answer CD55, responsive to cAMP signaling, is deficient in decidua of patients with unexplained early miscarriage, which hinders decidualization in vitro through perturbing Src/ERK signaling pathway. What is known already Decidualization is a process where HESCs differentiate into decidual stromal cells and present morphological changes and acquisition of secretory function, which is essential for embryo implantation and maintenance of pregnancy while abnormal decidualization contributed to several pregnancy disorders like a miscarriage. Reprogramming of several signaling pathways and transcription factors are involved in this process and cAMP is a critical mediator. Our previous bioinformatic analysis revealed that CD55 was upregulated over five times in the window of implantation, responding to estrogen and progesterone. We speculated that CD55, regulated by cAMP signaling pathway, might play an important role in decidualization. Study design, size, duration Decidua tissues were collected from 8 patients with unexplained early miscarriage and 10 control women with normal early pregnancy undergoing artificial abortion between June 2020 and September 2020. Immortalized HESCs line T-hESCs (ATCC CRL-4003) were cultured for up to 6 days to establish in-vitro decidualization model. Each experiment was conducted in triplicate and replicated at least three times independently. Participants/materials, setting, methods CD55 expression in control and miscarriage decidua was compared by immunohistochemistry and RT-qPCR. T-hESCs were induced into decidualization by medroxyprogesterone acetate (MPA) and 8-Br-cAMP, with prolactin (PRL) and insulin-like growth factor-binding protein 1 (IGFBP1) as decidualization biomarkers. The changes of genes and signaling pathways were detected by RT-qPCR and western blot during decidualization after CD55 knockdown by lentivirus-mediated RNA interference. Signaling pathway disruptors were added to verify the involvement of signaling pathways. Main results and the role of chance The decidua of women with unexplained early miscarriage exhibited decreased expression of CD55, accompanied by a compromised level of decidualization. During in-vitro decidualization, CD55 was significantly upregulated by cAMP in a time- and dose-dependent manner, which was attenuated by a PKA inhibitor H89. Knocking down CD55 expression diminished the expression of decidualization markers PRL and IGFBP1 through inhibition of Src, aberrant activation of ERK and frustrated expression of decidualization-related genes like FOXO1, EGFR, and STAT3. Limitations, reasons for caution The mechanisms revealed in this study were based on in-vitro cell models. It is necessary to verify the significance of CD55 in decidualization with in-vivo models to directly explain the link between CD55, decidualization, and pregnancy loss. Wider implications of the findings CD55 deficiency hinders decidualization through perturbing Src/ERK signaling pathway and expression of decidualization-related genes, potentially contributing to the pathogenesis of spontaneous miscarriage. Progestin supplementation or other factors stimulating cAMP accumulation can restore CD55 expression and improve decidualization, providing a basis for the therapy of spontaneous miscarriage. Trial registration number not applicable

Deletion of endothelial IGFBP5 protects against ischaemic hindlimb injury by promoting angiogenesis.

Angiogenesis is critical for forming new blood vessels from antedating vascular vessels. The endothelium is essential for angiogenesis, vascular remodelling and minimisation of functional deficits following ischaemia. The insulin-like growth factor (IGF) family is crucial for angiogenesis. Insulin-like growth factor-binding protein 5 (IGFBP5), a binding protein of the IGF family, may have places in angiogenesis, but the mechanisms are not yet completely understood. We sought to probe whether IGFBP5 is involved in pathological angiogenesis and uncover the molecular mechanisms behind it. IGFBP5 expression was elevated in the vascular endothelium of gastrocnemius muscle from critical limb ischaemia patients and hindlimb ischaemic (HLI) mice and hypoxic human umbilical vein endothelial cells (HUVECs). In vivo, loss of endothelial IGFBP5 (IGFBP5EKO) facilitated the recovery of blood vessel function and limb necrosis in HLI mice. Moreover, skin damage healing and aortic ring sprouting were faster in IGFBP5EKO mice than in control mice. In vitro, the genetic inhibition of IGFBP5 in HUVECs significantly promoted tube formation, cell proliferation and migration by mediating the phosphorylation of IGF1R, Erk1/2 and Akt. Intriguingly, pharmacological treatment of HUVECs with recombinant human IGFBP5 ensued a contrasting effect on angiogenesis by inhibiting the IGF1 or IGF2 function. Genetic inhibition of IGFBP5 promoted cellular oxygen consumption and extracellular acidification rates via IGF1R-mediated glycolytic adenosine triphosphate (ATP) metabolism. Mechanistically, IGFBP5 exerted its role via E3 ubiquitin ligase Von Hippel-Lindau (VHL)-regulated HIF1α stability. Furthermore, the knockdown of the endothelial IGF1R partially abolished the reformative effect of IGFBP5EKO mice post-HLI. Our findings demonstrate that IGFBP5 ablation enhances angiogenesis by promoting ATP metabolism and stabilising HIF1α, implying IGFBP5 is a novel therapeutic target for treating abnormal angiogenesis-related conditions.

Yak IGFBP3 promotes hepatocyte proliferation through PI3K-Akt signaling pathway

IGFBP3 (Insulin-like growth factor binding protein 3) constitutes a crucial constituent of the insulin-like growth factor (IGF), which are intimately associated with the organism's growth and development processes. Despite its significance, the precise function of IGFBP3 in yak liver development remains largely unexplored. In the present study, we systematically examined the expression profile of IGFBP3 in the liver tissues of yaks across various growth stages, elucidated its influence on the activity of yak hepatocytes, and probed its effects on murine liver development. A comparative analysis revealed that the expression of IGFBP3 was significantly higher in the liver tissue of 5-year-old yaks compared to their 15-month-old and 1-day-old counterparts (P < 0.01). To further validate its biological function, pET-28a-BgIGFBP3 prokaryotic expression vector was constructed. Upon exposing yak hepatocytes to varying concentrations of Bos grunniens (Bg) IGFBP3 protein, we observed augmented cellular activities and elevated colony formation rates. Moreover, our investigation revealed the upregulation of key genes within the PI3K-Akt signaling pathway, including ERBB2, IRS1, PIK3R1, AKT1, RAF1, MAP2K2, and MAPK3, in both yak hepatocyte cultures and murine models. These findings collectively indicate that BgIGFBP3 promotes the proliferation of yak hepatocytes and enhances murine liver development by modulating the PI3K-Akt signaling pathway. The functional relevance of BgIGFBP3 was substantiated through in vivo and in vitro experiments, thereby underscoring its potential as a regulatory factor in liver development processes.

Abstract LB093: Low IGFBP7 expression identifies a subset of breast cancers with favorable prognosis and sensitivity to IGF-1 receptor targeting with ganitumab: Data from I-SPY2 and SCAN-B

Abstract Background and Hypothesis: To date, no IGF-1R targeting agent has shown clinical benefit in patients despite promising preclinical data. We hypothesized that Insulin-like growth factor binding protein-7 (IGFBP7) expression predicts response to Insulin-like growth factor-1 receptor (IGF-1R) targeting agents, for which there are no biomarkers predictive of efficacy. High IGFBP7 expression was previously associated with breast cancer progression. Materials and Methods: The predictive value of IGFBP7 expression was interrogated in I-SPY2 (NCT01042379) for pathological complete response (pCR) to neoadjuvant treatment and in SCAN-B (NCT02306096) for clinical outcome. In I-SPY2, IGFBP7 expression was examined as a predictor of pCR to neoadjuvant chemotherapy alone and separately to the combination of chemotherapy plus ganitumab (anti-IGF-1R antibody) and metformin. Odds ratios (OR) and hazard ratios (HR) with 95% confidence interval (CI) were calculated with logistic and Cox regression, respectively. Results: Higher IGFBP7 expression conferred lower odds of achieving pCR in the ganitumab/metformin plus chemotherapy arm, ORadj 0.38 (95% CI 0.17-0.80) but not in the chemotherapy-alone arm, adjusted OR 1.23 (95% CI 0.63-2.45; P interaction=0.016). In the ganitumab/metformin plus chemotherapy arm, 46.9% of patients with tumors in the lowest quartile of IGFBP7 expression achieved pCR compared to compared to only 5.6% in the highest quartile. In SCAN-B, higher IGFBP7 expression was associated with distant metastasis risk HRadj 1.41 (95% CI 1.16-1.73). Conclusion: Low IGFBP7 gene expression identifies a subset of breast cancer patients for whom the addition of ganitumab and metformin to chemotherapy results in a significantly improved pCR rate compared to neoadjuvant chemotherapy alone. Furthermore, we add to prior evidence that high IGFBP7 expression is predictive of poor outcome. Citation Format: Christopher Godina, Michael N. Pollak, Helena Jernström. Low IGFBP7 expression identifies a subset of breast cancers with favorable prognosis and sensitivity to IGF-1 receptor targeting with ganitumab: Data from I-SPY2 and SCAN-B [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB093.

Metformin enhances epithelial cell growth inhibition via the protein kinase–insulin-like growth factor binding protein-1 pathway

Background Abnormal stromal-epithelial cell communication is a pathogenic mechanism in endometriosis, and metformin can modulate it. Insulin-like growth factor binding protein-1 (IGFBP1) plays a role in endometriosis, but the exact mechanism is unknown. IGFBP1 is reportedly a downstream target of metformin in some diseases. We aimed to investigate the role of IGFBP1 in endometriosis development, whether it is associated with abnormal communication, and whether metformin affects IGFBP1 expression. Methods Patients who underwent surgical treatment for endometriosis or other diseases were enrolled. Ten patients with ovarian-type endometriosis and eight patients each who underwent surgical treatment for other lesions with or without endometriosis were selected, and their tissues taken for cell proliferation, western blotting, polymerase chain reaction, and knockdown experiments. Results Ectopic and eutopic stromal cells (EcSCs and EuSCs) lost their ability to inhibit epithelial cell proliferation, and IGFBP1 expression was downregulated in both groups of stromal cells compared to that in normal stromal cells (NSCs; 1.09 vs. 0.25, p = .0002 1.09 vs. 0.57, p = .0029). In an EcSC IGFBP1 overexpression model, the ability of EcSCs to inhibit epithelial cell proliferation was enhanced (EdU positivity decreased from 38% to 25%, p = .0001). Furthermore, adenosine 5’-monophosphate-activated protein kinase (AMPK) phosphorylation was downregulated in EcSCs and EuSCs compared to that in NSCs (0.99 vs. 0.42, p = .0006/0.99 vs. 0.57, p = 0.0032). Treatment of EcSCs with metformin increased AMPK phosphorylation (0.47 vs. 1.04, p = .0107) while upregulating IGFBP1 expression (0.69 vs. 1.01, p = .0164), whereas pre-treatment with an AMPK phosphorylation inhibitor abrogated metformin-induced IGFBP1 upregulation. Conclusions IGFBP1 mediates aberrant stromal-epithelial communication in endometriosis. Metformin can upregulate IGFBP1 expression in EcSCs by activating AMPK, and upregulated IGFBP1 enhances the inhibition of epithelial cell proliferation. IGFBP1 is expected to be a therapeutic target for endometriosis.

Prior Exposure to Experimental Preeclampsia Increases Atherosclerotic Plaque Inflammation in Atherogenic Mice-Brief Report.

Women with a history of preeclampsia have evidence of premature atherosclerosis and increased risk of myocardial infarction and stroke compared with women who had a normotensive pregnancy. Whether this is due to common risk factors or a direct impact of prior preeclampsia exposure has never been tested in a mouse atherosclerosis model. Pregnant LDLR-KO (low-density lipoprotein receptor knockout; n=35) female mice were randomized in midgestation to sFlt1 (soluble fms-like tyrosine kinase 1)-expressing adenovirus or identical control adenovirus. Postpartum, mice were fed high-fat diet for 8 weeks to induce atherogenesis. Comparison between the control and preeclampsia models was made for metabolic parameters, atherosclerosis burden and composition by histology, plaque inflammation by flow cytometry, and aortic cytokines and inflammatory markers using a cytokine array. In pregnant LDLR-KO mice, sFlt1 adenovirus significantly induced serum sFlt1, blood pressure, renal endotheliosis, and decreased pup viability. After 8 weeks of postpartum high fat feeding, body weight, fasting glucose, plasma cholesterol, HDL (high-density lipoprotein), and LDL (low-density lipoprotein) were not significantly different between groups with no change in aortic root plaque size, lipid content, or necrotic core area. Flow cytometry demonstrated significantly increased CD45+ aortic arch leukocytes and CD3+T cells and aortic lysate contained more CCL (CC motif chemokine ligand) 22 and fetuin A and decreased expression of IGFBP6 (insulin-like growth factor-binding protein 6) and CCL21 in preeclampsia-exposed mice compared with controls. In atherogenic LDLR-KO mice, exposure to sFlt1-induced preeclampsia during pregnancy increases future atherosclerotic plaque inflammation, supporting the concept that preeclampsia directly exacerbates atherosclerotic inflammation independent of preexisting risk factors. This mechanism may contribute to ischemic vascular disease in women after preeclampsia pregnancy.