Recent insights into the actions of IGFBP-6

IGFBP6 regulates extracellular vesicles formation via cholesterol abundance in MDA-MB-231 cells

Breast cancer recurrence is associated with the growth of disseminated cancer cells that separate from the primary tumor before surgical treatment and hormonal therapy and form a metastatic niche in distant organs. We previously demonstrated that IGFBP6 expression is associated with the risk of early relapse of luminal breast cancer. Knockdown of IGFBP6 in MDA-MB-231 breast cancer cells increased their invasiveness, proliferation, and metastatic potential. In addition, the knockdown of IGFBP6 leads to impaired lipid metabolism. In this study, we demonstrated that the knockdown of the IGFBP6 gene, a highly selective inhibitor of IGF-II, led to a significant decline in the number of secreted extracellular vesicles (EVs) and altered cholesterol metabolism in MDA-MB-231 cells. Knockdown of IGFBP6 led to a decrease in the essential proteins responsible for the biogenesis of cholesterol LDLR and LSS, which reduced the amount by more than 13 times. In addition, the knockdown of IGFBP6 led to a possible change in the profile of adhesion molecules on the surface of EVs. The expression of L1CAM, IGSF3, EpCAM, CD24, and CD44 decreased, and the expression of EGFR increased. We can conclude that the negative prognostic value of low expression of this gene could be associated with increased activity of IGF2 in tumor-associated fibroblasts due to low secretion of IGFBP6 by tumor cells. In addition, changing the profile of adhesion molecules on the surface of tumor EVs may contribute to the more efficient formation of metastatic niches.

Prohibitions in the meta-inflammatory response: a review

Prohibitins are the central regulatory element of cellular homeostasis, especially by modulating the response at different levels: Nucleus, mitochondria and membranes. Their localization and interaction with various proteins, homons, transcription and nuclear factors, and mtDNA indicate the globality and complexity of their pleiotropic properties, which remain to be investigated. A more detailed deciphering of cellular metabolism in relation to prohibitins under normal conditions and in various metabolic diseases will allow us to understand the precise role of prohibitins in the signaling cascades of PI3K/Akt, Raf/MAP/ERK, STAT3, p53, and others and to fathom their mutual influence. A valuable research perspective is to investigate the role of prohibitins in the molecular and cellular interactions between the two major players in the pathogenesis of obesity-adipocytes and macrophages - that form the basis of the meta-inflammatory response. Investigating the subtle intercellular communication and molecular cascades triggered in these cells will allow us to propose new therapeutic strategies to eliminate persistent inflammation, taking into account novel molecular genetic approaches to activate/inactivate prohibitins.

Platinum-induced upregulation of ITGA6 promotes chemoresistance and spreading in ovarian cancer

Platinum (PT)-resistant Epithelial Ovarian Cancer (EOC) grows as a metastatic disease, disseminating in the abdomen and pelvis. Very few options are available for PT-resistant EOC patients, and little is known about how the acquisition of PT-resistance mediates the increased spreading capabilities of EOC. Here, using isogenic PT-resistant cells, genetic and pharmacological approaches, and patient-derived models, we report that Integrin α6 (ITGA6) is overexpressed by PT-resistant cells and is necessary to sustain EOC metastatic ability and adhesion-dependent PT-resistance. Using in vitro approaches, we showed that PT induces a positive loop that, by stimulating ITGA6 transcription and secretion, contributes to the formation of a pre-metastatic niche enabling EOC cells to disseminate. At molecular level, ITGA6 engagement regulates the production and availability of insulin-like growth factors (IGFs), over-stimulating the IGF1R pathway and upregulating Snail expression. In vitro data were recapitulated using in vivo models in which the targeting of ITGA6 prevents PT-resistant EOC dissemination and improves PT-activity, supporting ITGA6 as a promising druggable target for EOC patients.

Evaluation of in vitro and in vivo anticancer activities of potassium koetjapate: a solubility improved formulation of koetjapic acid against human colon cancer

Background and purpose

The previous work on koetjapic acid (KA) isolated from Sandoricum koetjape showed its efficacy towards colorectal cancer however KA has poor water solubility which poses the biggest hindrance to its efficacy. In the present paper, an attempt was made to study the anti-colon cancer efficacy of KA's potassium salt i.e. potassium koetjapate (KKA) applying in vitro and in vivo methods.

Experimental approach

KKA was produced by a semi-synthetic method. A human apoptosis proteome profiler array was applied to determine the protein targets responsible for the stimulation of apoptosis. Three doses of KKA were studied in athymic nude mice models to examine the in vivo anti-tumorigenic ability of KKA.

Findings/Results

The results of this study demonstrated that KKA regulates the activities of various proteins. It downregulates the expression of several antiapoptotic proteins and negative regulators of apoptosis including HSP60, HSP90, Bcl-2, and IGF-1 in HCT 116 cells with consequent upregulation of TRAILR-1 and TRAILR-2, p27, CD40, caspase 3, and caspase 8 proteins. Additionally, KKA showed an in vitro antimetastatic effect against HCT 116 cells. These results are feasibly related to the down-regulation of Notch, Wnt, hypoxia, and MAPK/JNK and MAPK/ERK signalling pathways in HCT 116 cells besides the up-regulation of a transcription factor for cell cycle (pRb-E2F) pathways. In addition, KKA revealed potent inhibition of tumor growth.

Conclusion and implications

In sum, the findings indicate that KKA can be a promising candidate as a chemotherapeutic agent against colorectal cancer.

Ginger exosome-like nanoparticles (GELNs) induced apoptosis, cell cycle arrest, and anti-metastatic effects in triple-negative breast cancer MDA-MB-231 cells

Ginger exosome-like nanoparticles (GELNs) have been extensively implicated in alleviating inflammation, maintaining intestinal microbiome and are considered competent drug delivery vehicles. Despite this, the current knowledge of the GELN interaction with cancer cells is limited. Triple-negative breast cancer (TNBC), an aggressive variant lacking efficient therapeutics, necessitates novel natural counterparts with minimal side effects. This study investigates the action of GELNs isolated from ginger rhizomes against TNBC cells. GELNs were isolated by ultracentrifugation and characterized physicochemically. The interaction of GELNs with TNBC cells (MDA-MB-231) was studied in detail. The GELNs induced a concentration-dependent decrease in cell viability in MDA-MB-231 cells without affecting the normal cell lines tested. GELNs induced apoptosis as indicated by morphological changes, nuclear fragmentation, membrane damage, phosphatidyl serine translocation, ROS generation, drop in mitochondrial membrane potential, expression of apoptotic specific proteins, and increased caspase activity. GELNs also instigated cell cycle arrest, retarded cell migration and colony formation in TNBC cells. These findings report a novel action of GELNs against TNBC cells and a closer look at the underlying molecular mechanism of this interspecies communication. This opens newer prospects for using dietary ELNs to target therapeutically challenging cancers.

Complement system dysregulation in synovial fluid from patients with persistent inflammation following anterior cruciate ligament reconstruction surgery

Introduction

Patients with anterior cruciate ligament injury are at high risk of posttraumatic osteoarthritis and their response to reconstructive surgery and rehabilitation vary. Proteins identified in the orchestration of the acute inflammatory response may be predictive of patient outcomes.

Objective

An unbiased, bottom-up proteomics approach was used to discover novel targets for therapeutics in relation to dysregulation in the orchestration of inflammatory pathways implicated in persistent joint inflammation subsequent to joint trauma.

Methods

Synovial fluid was aspirated from patients at 1 week and 4 weeks after anterior cruciate ligament reconstruction (ACLR) and interleukin 6 (IL-6) concentrations were quantified by enzyme-linked immunosorbent assay. Patients were segregated into IL-6low and IL-6high groups based on IL-6 concentrations in synovial fluid at 4-weeks postoperation and proteins in synovial fluid were analyzed using qualitative, bottom-up proteomics. Abundance ratios were calculated for IL-6high and IL-6low groups as 4 weeks postoperation:1 week postoperation.

Results

A total of 291 proteins were detected in synovial fluid, 34 of which were significantly (P < .05) differentially regulated between groups. Proteins associated with the classical and alternative complement cascade pathways were increased in the IL-6high compared to IL-6low group. Insulin-like growth factor-binding protein 6 (IGFBP-6) was increased by nearly 60-fold in the IL-6low group.

Conclusions

Patients segregated by IL-6 concentration in synovial fluid at 4 weeks post-ACLR demonstrated differential regulation of multiple pathways, providing opportunities to investigate novel targets, such as IGFBP-6, and to take advantage of therapeutics already approved for clinical use in other diseases that target inflammatory pathways, including the complement system.

Treatment of critical bone defects using calcium phosphate cement and mesoporous bioactive glass providing spatiotemporal drug delivery

Calcium phosphate cements (CPC) are currently widely used bone replacement materials with excellent bioactivity, but have considerable disadvantages like slow degradation. For critical-sized defects, however, an improved degradation is essential to match the tissue regeneration, especially in younger patients who are still growing. We demonstrate that a combination of CPC with mesoporous bioactive glass (MBG) particles led to an enhanced degradation in vitro and in a critical alveolar cleft defect in rats. Additionally, to support new bone formation the MBG was functionalized with hypoxia conditioned medium (HCM) derived from rat bone marrow stromal cells. HCM-functionalized scaffolds showed an improved cell proliferation and the highest formation of new bone volume. This highly flexible material system together with the drug delivery capacity is adaptable to patient specific needs and has great potential for clinical translation.

Insulin-like growth factor (IGF) performance in ovarian function and applications in reproductive biotechnologies

The role of the insulin-like growth factor (IGF) system has attracted close attention. The activity of IGF binding proteins (IGFBPs) within the ovary has not been fully elucidated to date. These proteins bind to IGF with an equal, or greater, affinity than to the IGF1 receptor, thus being in the main position to regulate IGF signalling, in addition to extending the half-life of IGFs within the bloodstream and promoting IGF storage in specific tissue niches. IGF1 has an important part in cell proliferation, differentiation and apoptosis. Considering the importance of IGFs in oocyte maturation, this review sought to elucidate aspects including: IGF production mechanisms; constituent members of their family and their respective functions; the role that these factors play during folliculogenesis, together with their functions during oocyte maturation and apoptosis, and their performance during luteal development. This review also explores the role of IGFs in biotechnological applications, focusing specifically on animal genetic gain.

ELOVL5 and IGFBP6 genes modulate sensitivity of breast cancer cells to ferroptosis

Introduction: Relapse of breast cancer is one of the key obstacles to successful treatment. Previously we have shown that low expression of ELOVL5 and IGFBP6 genes in breast cancer tissue corresponded to poor prognosis. ELOVL5 participates directly in the elongation of polyunsaturated fatty acids (PUFAs) that are considered to play an important role in cancer cell metabolism. Thus, in this work we studied the changes in lipid metabolism in breast cancer cells with reduced expression of either ELOVL5 or IGFBP6 gene. Methods: MDA-MB-231 cells with a stable knockdown of either ELOVL5 or IGFBP6 gene were used in this study. Transcriptomic and proteomic analysis as well as RT-PCR were utilized to assess gene expression. Content of individual fatty acids in the cells was measured with HPLC-MS. HPLC was used for analysis of the kinetics of PUFAs uptake. Cell viability was measured with MTS assay. Flow cytometry was used to measure activation of apoptosis. Fluorescent microscopy was utilized to assess accumulation of ROS and formation of lipid droplets. Glutathione peroxidase activity was measured with a colorimetric assay. Results: We found that the knockdown of IGFBP6 gene led to significant changes in the profile of fatty acids in the cells and in the expression of many genes associated with lipid metabolism. As some PUFAs are known to inhibit proliferation and cause death of cancer cells, we also tested the response of the cells to single PUFAs and to combinations of docosahexaenoic acid (DHA, a n-3 PUFA) with standard chemotherapeutic drugs. Our data suggest that external PUFAs cause cell death by activation of ferroptosis, an iron-dependent mechanism of cell death with excessive lipid peroxidation. Moreover, both knockdowns increased cells' sensitivity to ferroptosis, probably due to a significant decrease in the activity of the antioxidant enzyme GPX4. Addition of DHA to commonly used chemotherapeutic drugs enhanced their effect significantly, especially for the cells with low expression of IGFBP6 gene. Discussion: The results of this study suggest that addition of PUFAs to the treatment regimen for the patients with low expression of IGFBP6 and ELOVL5 genes can be potentially beneficial and is worth testing in a clinically relevant setting.

Osteoblast Secretome Modulated by Abiraterone Treatment Affects Castration Resistant Prostate Cancer Cell Proliferation

Abiraterone is a selective inhibitor of androgen biosynthesis approved for the treatment of metastatic patients affected by castration-resistant or castration-sensitive prostate cancer. Intriguingly, clinical data revealed that abiraterone also delayed disease progression in bone improving bone-related endpoints. Our group has previously demonstrated in vitro a direct effect of abiraterone on osteoclast and osteoblast function suggesting its ability to modulate bone microenvironment. Here, we performed an extensive proteomic analysis to investigate how abiraterone influences osteoblast cell secretome and, consequently, osteoblast/prostate cancer cells interaction. A panel of 507 soluble molecules were analyzed in osteoblast conditioned media (OCM) obtained from osteoblast treated or not with abiraterone. Subsequently, OCM was added to prostate cancer cells to investigate its potential effect on prostate cancer cell proliferation and androgen receptor (AR) activation status. Out of 507 screened molecules, 39 of them were differentially expressed in OCM from osteoblasts treated with abiraterone (OCM ABI) compared to OCM obtained from untreated OBs (OCM CTRL). Pathway enrichment analysis revealed that abiraterone down-modulated the release of specific osteoblast soluble factors, positively associated with cell proliferation pathways (false discovery rate adjusted p-value = 0.0019). In vitro validation data showed that OCM ABI treatment significantly reduced cancer proliferation in C4-2B cells (p = 0.022), but not in AR- negative PC-3 cells. Moreover, we also found a reduction in AR activation in C4-2B cells (p = 0.017) confirming the “indirect” anti-tumor AR-dependent effect of abiraterone mediated by osteoblasts. This study provides the first evidence of an additional antitumor effect of abiraterone through the modulation of multiple osteoblast proliferative signals.

The Insulin-like Growth Factor System and Colorectal Cancer

Insulin-like growth factors (IGFs) are peptides which exert mitogenic, endocrine and cytokine activities. Together with their receptors, binding proteins and associated molecules, they participate in numerous pathophysiological processes, including cancer development. Colorectal cancer (CRC) is a disease with high incidence and mortality rates worldwide, whose etiology usually represents a combination of the environmental and genetic factors. IGFs are most often increased in CRC, enabling excessive autocrine/paracrine stimulation of the cell growth. Overexpression or increased activation/accessibility of IGF receptors is a coinciding step which transmits IGF-related signals. A number of molecules and biochemical mechanisms exert modulatory effects shaping the final outcome of the IGF-stimulated processes, frequently leading to neoplastic transformation in the case of irreparable disbalance. The IGF system and related molecules and pathways which participate in the development of CRC are the focus of this review.

Comparative Genomic Characterization of Insulin-Like Growth Factor Binding Proteins in Cattle and Buffalo

The somatotropic axis consists of genes associated with economic traits like muscle growth and carcass traits in livestock. Insulin-like growth factor binding proteins (IGFBPs) are the major proteins that play a vital role in the somatotropic axis. The present study performed a genome-wide characterization of IGFBP genes in cattle. Genomic sequences of the IGFBP gene family for different mammals (cattle, buffalo, goat, and sheep) were recovered from the NCBI database. Sequence analyses were performed to investigate cattle's genomic variations in the IGFBP gene family. Phylogenetic analysis, gene structure, motif patterns, and conserved domain analysis (CDA) of the IGFBP family revealed the evolutionarily conserved nature of the IGFBP genes in cattle and other studied species. Physicochemical properties of IGFBP proteins in cattle revealed that most of these proteins are unstable, hydrophilic, thermostable, and acidic. Comparative amino acid analysis revealed variations in all protein sequences with single indels in IGFBP3 and IGFBP6. Mutation analysis revealed only one nonsynonymous mutation D212 > E in the IGFBP6 protein of cattle. A total of 245 nuclear hormone receptor (NHRs) sites were detected, including 139 direct repeats (DR), 65 everted repeats (ER), and 41 inverted repeats (IR). Out of 133 transcription factors (TFs), 10 TFs (AHR, AHRARNT, AP4, CMYB, E47, EGR2, GATA, SP1, and SRF) had differential distribution (P value < 0.05) of putative transcriptional binding sites (TFBS) in cattle compared to buffalo. Synteny analysis revealed the conserved nature of genes between cattle and buffalo. Two gene pairs (IGFBP1/IGFBP3 and IGFBP2/IGFBP5) showed tandem duplication events in cattle and buffalo. This study highlights the functional importance of genomic variation in IGFBP genes and necessitates further investigations better to understand the role and mechanisms of IGFBPs in bovines.

Comprehensive Analysis of Prognostic Value and Immune Infiltration of IGFBP Family Members in Glioblastoma

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. The insulin-like growth factor-binding protein (IGFBP) family is involved in tumorigenesis and the development of multiple cancers. However, little is known about the prognostic value and regulatory mechanisms of IGFBPs in GBM. Oncomine, Gene Expression Profiling Interactive Analysis, PrognoScan, cBioPortal, LinkedOmics, TIMER, and TISIDB were used to analyze the differential expression, prognostic value, genetic alteration, biological function, and immune cell infiltration of IGFBPs in GBM. We observed that IGFBP1, IGFBP2, IGFBP3, IGFBP4, and IGFBP5 mRNA expression was significantly upregulated in patients with GBM, whereas IGFBP6 was downregulated; this difference in mRNA expression was statistically insignificant. Subsequent investigations showed that IGFBP4 and IGFBP6 mRNA levels were significantly associated with overall survival in patients with GBM. Functional Gene Ontology Annotation and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that genes coexpressed with IGFBP4 and IGFBP6 were mainly enriched in immune-related pathways. These results were validated using the TIMER and TSMIDB databases. This study demonstrated that the IGFBP family has prognostic value in patients with GBM. IGFBP4 and IGFBP6 are two members of the IGFBP family that had the highest prognostic value; thus, they have the potential to serve as survival predictors and immunotherapeutic targets in GBM.

Differential and divergent activity of insulin‑like growth factor binding protein 6 in platinum‑sensitive versus platinum‑resistant high‑grade serous ovarian carcinoma cell lines

Insulin-like growth factor binding protein 6 (IGFBP6) is a secreted protein with a controversial role in human malignancies, being downregulated in most types of human cancer, but upregulated in selected tumors. Ovarian cancer (OC) is a human malignancy characterized by IGFBP6 downregulation; however, the significance of its low expression during ovarian carcinogenesis is still poorly understood. In the present study, IGFBP6 expression and activation of its associated signaling pathway were evaluated in two matched OC cell lines derived from a high-grade serous OC before and after platinum resistance (PEA1 and PEA2 cells, respectively). A whole genome gene expression analysis was comparatively performed in both cell lines upon IGFBP6 stimulation using Illumina technology. IGFBP6 gene expression data from human OC cases were obtained from public datasets. Gene expression data from public datasets confirmed the downregulation of IGFBP6 in primary and metastatic OC tissues compared with in normal ovarian tissues. The comparative analysis of platinum-sensitive (PEA1) and platinum-resistant (PEA2) cell lines showed quantitative and qualitative differences in the activation of IGFBP6 signaling. Notably, IGFBP6 enhanced ERK1/2 phosphorylation only in PEA1 cells, and induced more evident and significant gene expression reprogramming in PEA1 cells compared with in PEA2 cells. Furthermore, the analysis of selected genes modulated by IGFBP6 (i.e., FOS, JUN, TNF, IL6, IL8 and EGR1) exhibited an inverse regulation in PEA1 versus PEA2 cells. In addition, selected hallmarks (TNFA_signaling_via_NFKB, TGF_beta_signaling, P53_pathway) and IL-6 signaling were positively regulated in PEA1 cells, whereas they were inhibited in PEA2 cells in response to IGFBP6. These data suggested that dysregulation of IGFBP6 signaling may serve a role in the progression of OC, and is likely associated with the development of platinum resistance.

IGFBP-6: At the Crossroads of Immunity, Tissue Repair and Fibrosis

Insulin-like growth factors binding protein-6 (IGFBP-6) is involved in a relevant number of cellular activities and represents an important factor in the immune response, particularly in human dendritic cells (DCs). Over the past several years, significant insights into the IGF-independent effects of IGFBP-6 were discovered, such as the induction of chemotaxis, capacity to increase oxidative burst and neutrophils degranulation, ability to induce metabolic changes in DCs, and, more recently, the regulation of the Sonic Hedgehog (SHH) signaling pathway during fibrosis. IGFBP-6 has been implicated in different human diseases, and it plays a rather controversial role in the biology of tumors. Notably, well established relationships between immunity, stroma activity, and fibrosis are prognostic and predictive of response to cancer immunotherapy. This review aims at describing the current understanding of mechanisms that link IGFBP-6 and fibrosis development and at highlighting the multiple roles of IGFBP-6 to provide an insight into evolutionarily conserved mechanisms that can be relevant for inflammation, tumor immunity, and immunological diseases.

Coadministration with bendamustine restores the antitumor activity of obinutuzumab in obinutuzumab-resistant tumors

BACKGROUND

The glycoengineered, humanized anti-CD20 antibody obinutuzumab is indicated for previously untreated or relapsed/refractory CD20-positive follicular lymphoma (FL). However, the effectiveness of obinutuzumab retreatment in relapsed/refractory FL after prior obinutuzumab-containing therapy is unclear. To address this issue, we investigated the antitumor activity of obinutuzumab plus bendamustine in obinutuzumab-resistant tumors established from a human non-Hodgkin lymphoma xenograft model.

MATERIALS AND METHODS

Obinutuzumab-resistant tumors (SU-DHL-4-OR-18-8) were established from an SU-DHL-4 xenograft model by repeated administration of obinutuzumab. Antitumor activity was evaluated based on tumor volume after treatment with obinutuzumab on Day 1, 8, and 15 and/or bendamustine on Day 1 and 2. Intratumoral natural killer (NK) cells/macrophages were evaluated by immunohistochemistry and flow cytometry.

RESULTS

In SU-DHL-4-OR-18-8 xenografted tumors, intratumoral NK cells/macrophages after obinutuzumab treatment were significantly decreased compared with parent tumors on Day 4. The endoplasmic reticulum stress sensor phospho-IRE1 was also decreased. In SU-DHL-4-OR-18-8 tumors, bendamustine treatment increased phospho-IRE1 on Day 4 and intratumor NK cells/macrophages on Day 10. Obinutuzumab combined with bendamustine significantly increased antitumor activity compared with each single agent on Day 29, with an increase in chemoattractant CCL6 expression on Day 10.

CONCLUSIONS

Coadministration of bendamustine in obinutuzumab retreatment may be effective against obinutuzumab-resistant tumors.

The Crosstalk between GPR81/IGFBP6 Promotes Breast Cancer Progression by Modulating Lactate Metabolism and Oxidative Stress

Breast cancer is the most frequent tumor and the leading cause of cancer deaths in women. In recent years, lactate metabolism and, in particular, its receptor GPR81 have been shown to play a vital role in cancer biology. GPR81 is upregulated in breast cancer and promotes tumor growth by tumor cell-derived lactate. Therefore, the search for possible crosstalk and the involvement of new molecules capable of generating this pathology is always in continuous development. In this study, the relationship between GPR81 and IGFBP6 protein in tumor growth and oxidative stress in the human breast cancer cell line MDA-MB-231 was studied. Cells were treated with lactate or the GPR81 receptor agonist and antagonist 3,5-DHBA and 3-OBA, respectively. In addition, oxidative stress and proliferation were also evaluated in cells challenged with the recombinant IGFBP6 protein. Our data showed that lactate induced cell proliferation and wound healing of the MDA-231 breast cancer cell through the overexpression of both the lactate receptor GPR81 and IGFBP6. The increase in IGFBP6 was able, in turn, to improve the mitochondrial fitness and redox state, as suggested by the reduced levels of mitochondrial ROS production after IGFBP6 treatment, presumably mediated by the increase in the ROS detoxifying genes HMOX1, GSTK1 and NQO1. In conclusion, our data highlight a novel axis between GPR81 and IGFBP6 in MDA-231 cells able to modulate lactate metabolism and oxidative stress. This complex signaling may represent a new therapeutic target for breast cancer.

The Effect of Diabetes Mellitus on IGF Axis and Stem Cell Mediated Regeneration of the Periodontium

Periodontitis and diabetes mellitus (DM) are two of the most common and challenging health problems worldwide and they affect each other mutually and adversely. Current periodontal therapies have unpredictable outcome in diabetic patients. Periodontal tissue engineering is a challenging but promising approach that aims at restoring periodontal tissues using one or all of the following: stem cells, signalling molecules and scaffolds. Mesenchymal stem cells (MSCs) and insulin-like growth factor (IGF) represent ideal examples of stem cells and signalling molecules. This review outlines the most recent updates in characterizing MSCs isolated from diabetics to fully understand why diabetics are more prone to periodontitis that theoretically reflect the impaired regenerative capabilities of their native stem cells. This characterisation is of utmost importance to enhance autologous stem cells based tissue regeneration in diabetic patients using both MSCs and members of IGF axis.

Diversity of developing peripheral glia revealed by single-cell RNA sequencing

The peripheral nervous system responds to a wide variety of sensory stimuli, a process that requires great neuronal diversity. These diverse neurons are closely associated with glial cells originating from the neural crest. However, the molecular nature and diversity among peripheral glia are not understood. Here, we used single-cell RNA sequencing to profile developing and mature glia from somatosensory dorsal root ganglia and auditory spiral ganglia. We found that glial precursors (GPs) in these two systems differ in their transcriptional profiles. Despite their unique features, somatosensory and auditory GPs undergo convergent differentiation to generate molecularly uniform myelinating and non-myelinating Schwann cells. By contrast, somatosensory and auditory satellite glial cells retain system-specific features. Lastly, we identified a glial signature gene set, providing new insights into commonalities among glia across the nervous system. This survey of gene expression in peripheral glia constitutes a resource for understanding functions of glia across different sensory modalities.

The clinical characteristics and prognostic value of IGFBP6 in glioma

BACKGROUND

Glioma is the most common intrinsic tumor in central nervous system and is characterized by their diffuse infiltration of the brain tissue. Insulin-like Growth Factor Binding Protein-6 (IGFBP6) was associated with the insulin-like growth factor binding and insulin-like growth factor II binding processes in many cancers. Herein, we aimed to investigate the biological functions and clinical features of IGFBP6 in gliomas.

METHODS

Totally, we collected 325 RNA sequencing data from CGGA dataset as training cohort, and 969 RNA sequencing data from TCGA dataset as validation cohort. The clinical and molecular characteristics analysis and gene ontology analysis of IGFBP6 were performed. All analyses and graphs were produced based on R language.

RESULTS

We found that IGFBP6 expression was significantly upregulated in GBM patients and downregulated in IDH mutant patients. Receiver Operating Characteristic (ROC) analysis revealed that IGFBP6 could be used as a biomarker to predict TCGA mesenchymal subtype. GO analysis revealed that IGFBP6 was correlated with immunological functions and inflammation activities. Meanwhile, higher expression of IGFBP6 suggested significant relationship with worse prognosis in glioma patients.

CONCLUSIONS

Our findings improved the understanding of IGFBP6 in glioma, and IGFBP6 might be a potential therapeutic target for glioma patients in future clinical trials.

Effect of the Expression of ELOVL5 and IGFBP6 Genes on the Metastatic Potential of Breast Cancer Cells

Breast cancer (BC) is the leading cause of death from malignant neoplasms among women worldwide, and metastatic BC presents the biggest problems for treatment. Previously, it was shown that lower expression of ELOVL5 and IGFBP6 genes is associated with a higher risk of the formation of distant metastases in BC. In this work, we studied the change in phenotypical traits, as well as in the transcriptomic and proteomic profiles of BC cells as a result of the stable knockdown of ELOVL5 and IGFBP6 genes. The knockdown of ELOVL5 and IGFBP6 genes was found to lead to a strong increase in the expression of the matrix metalloproteinase (MMP) MMP1. These results were in good agreement with the correlation analysis of gene expression in tumor samples from patients and were additionally confirmed by zymography. The knockdown of ELOVL5 and IGFBP6 genes was also discovered to change the expression of a group of genes involved in the formation of intercellular contacts. In particular, the expression of the CDH11 gene was markedly reduced, which also complies with the correlation analysis. The spheroid formation assay showed that intercellular adhesion decreased as a result of the knockdown of the ELOVL5 and IGFBP6 genes. Thus, the obtained data indicate that malignant breast tumors with reduced expression of the ELOVL5 and IGFBP6 genes can metastasize with a higher probability due to a more efficient invasion of tumor cells.

Genomic relevance of FGF14 and associated genes on the prognosis of pancreatic cancer

BACKGROUND

Fibroblast (FGFs) and insulin (IGF) growth factor pathways are among 10 most recurrently altered genomic pathways in pancreatic ductal adenocarcinoma (PDAC). However, the prognostic and therapeutic relevance of FGF and IGF pathways in PDAC is largely unknown.

METHODS

We investigated the relationship between fibroblast and insulin pathway gene expression and clinicopathological features in three independent transcriptomic cohorts of 532 PDAC patients. Furthermore, we have examined the coexpressed genes specific to the prognostic marker identified from these cohorts. Statistical tests including Fisher-exact\Chi-square, Kaplan-Meier, Pearson Correlation and cox regression analyses were performed. Additionally, pathway analysis of gene-specific co-expressed genes was also performed.

RESULTS

The dysregulation of six genes including FGF9, FGF14, FGFR1, FGFR4, IGF2BP2 and IGF2BP3 were significantly associated with different clinical characteristics (including grade, stage, recurrence and nodes) in PDAC cohorts. 11 genes (including FGF9, FGF13, FGF14, FGF17, FGFR1, FGFRL1, FGFBP3, IGFBP3, IGF2BP2, IGF2BP3 and IGFBPL1) showed association with overall survival in different PDAC cohorts. Interestingly, overexpression of FGF14 was found associated with better overall survival (OS) in all three cohorts. Of note, multivariate analysis also revealed FGF14 as an independent prognostic marker for better OS in all three cohorts. Furthermore, FMN2 and PGR were among the top genes that correlated with FGF14 in all 3 cohorts. Of note, overexpression of FMN2 and PGR was found significantly associated with good overall survival in PDAC patients, suggesting FMN2 and PGR can also act as potential markers for the prediction of prognosis in PDAC patients.

CONCLUSION

FGF14 may define a distinct subset of PDAC patients with better prognosis. Moreover, FGF14-based sub-classification of PDAC suggests that FMN2 and PGR can be employed as good prognostic markers in PDAC and this classification may lead to new therapeutic approaches.

The insulin-like growth factor system: A target for endocrine disruptors?

The insulin-like growth factor (IGF) system is a critical regulator of growth, especially during fetal development, while also playing a central role in metabolic homeostasis. Endocrine disruptors (EDs) are ubiquitous compounds able to interfere with hormone action and impact human health. For example, exposure to EDs is associated with decreased birthweight and increased incidence of metabolic disorders. Therefore, the IGF system is a potential target for endocrine disruption. This review summarises the state of the science regarding effects of exposure to major classes of endocrine disruptors (dioxins and dioxin-like compounds, polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers, phthalates, perfluoroalkyl substances and bisphenol A) on the IGF system. Evidence from both experimental models (in vitro and in vivo) and epidemiological studies is presented. In addition, possible molecular mechanisms of action and effects on methylation are discussed. There is a large body of evidence supporting the link between dioxins and dioxin-like compounds and IGF disruption, but mixed findings have been reported in human studies. On the other hand, although only a few animal studies have investigated the effects of phthalates on the IGF system, their negative association with IGF levels and methylation status has been more consistently reported in humans. For polybrominated diphenyl ethers, perfluoroalkyl substances and bisphenol A the evidence is still limited. Despite a lack of studies for some ED classes linking ED exposure to changes in IGF levels, and the need for further research to improve reproducibility and determine the degree of risk posed by EDs to the IGF system, this is clearly an area of concern.

DNA methylation changes in metabolic and immune-regulatory pathways in blood and lymph node CD4 + T cells in response to SIV infections

The molecular mechanisms underlying HIV-induced inflammation, which persists even during effective long-term treatment, remain incompletely defined. Here, we studied pathogenic and nonpathogenic simian immunodeficiency virus (SIV) infections in macaques and African green monkeys, respectively. We longitudinally analyzed genome-wide DNA methylation changes in CD4 + T cells from lymph node and blood, using arrays. DNA methylation changes after SIV infection were more pronounced in lymph nodes than blood and already detected in primary infection. Differentially methylated genes in pathogenic SIV infection were enriched for Th1-signaling (e.g., RUNX3, STAT4, NFKB1) and metabolic pathways (e.g., PRKCZ). In contrast, nonpathogenic SIVagm infection induced DNA methylation in genes coding for regulatory proteins such as LAG-3, arginase-2, interleukin-21 and interleukin-31. Between 15 and 18% of genes with DNA methylation changes were differentially expressed in CD4 + T cells in vivo. Selected identified sites were validated using bisulfite pyrosequencing in an independent cohort of uninfected, viremic and SIV controller macaques. Altered DNA methylation was confirmed in blood and lymph node CD4 + T cells in viremic macaques but was notably absent from SIV controller macaques. Our study identified key genes differentially methylated already in primary infection and in tissues that could contribute to the persisting metabolic disorders and inflammation in HIV-infected individuals despite effective treatment.

IGFBP6 regulates vascular smooth muscle cell proliferation and morphology via cyclin E-CDK2

Despite the high prevalence of varicose veins, the underlying pathogenesis of this disease remains unclear. The present study aims to explore the role of insulin-like growth factor binding protein 6 (IGFBP6) in vascular smooth muscle cells (VSMCs). Using a protein array approach, we identified several differentially expressed proteins between varicose great saphenous veins and normal great saphenous veins. Bioinformatic analysis showed that IGFBP6 was closely related to cell proliferation. Further validation confirmed that IGFBP6 was one of the most highly expressed proteins in varicose vein tissue. Knocking down IGFBP6 in VSMCs significantly attenuated cell proliferation and induced the S phase arrest during the cell cycle. Further experiments demonstrated that IGFBP6 knockdown increased cyclin E ubiquitination, which reduced expression of cyclin E and phosphorylation of CDK2. Furthermore, IGFBP6 knockdown arrested centrosome replication, which subsequently influenced VSMC morphology. Ultimately, IGFBP6 was validated to be involved in VSMC proliferation in varicose vein tissues. The present study reveals that IGFBP6 is closely correlated with VSMC biological function and provides unprecedented insights into the underlying pathogenesis of varicose veins.

Activity of the human immortalized endothelial progenitor cell line HEPC-CB.1 supporting in vitro angiogenesis

The human HEPC-CB.1 cell line with many characteristics of endothelial progenitor cells (EPC) was tested for its proangiogenic properties as a potentially therapeutic compound. HEPC-CB.1 cells’ potential to differentiate into endothelial cells was revealed after treating the cells with a mixture of ATRA, cAMP and VEGF, as shown by the reduced expression levels of CD133, CD271 and CD90 antigens, augmentation of CD146 and CD31, and a decrease in cell clonogenicity. The cooperation of HEPC-CB.1 with the endothelial cell line HSkMEC.2 resulted in the formation of a common network. Tube formation was significantly more effective when resulting from HEPC-CB.1 and HSkMEC.2 cell co-culture as compared to a monoculture of each cell line. The exocrine mechanism of HEPC-CB.1 and HSkMEC.2 cross talk by secreted factors was evidenced using the HEPC-CB.1 supernatant to increase the efficacy of HSkMEC.2 tube formation. The proangiogenic factors produced by HEPC-CB.1 were identified using cytokine antibody array. Out of 120 examined factors, the HEPC-CB.1 cell line produced 63, some with known angiogenic activity. As in vivo the angiogenic process occurs at low oxygen tension, it was observed that in hypoxia, the production of defined factors was augmented. The presented results demonstrate that HEPC-CB.1 cells are able to both cooperate and integrate in a newly formed network and produce factors that help the network formation. The results suggest that HEPC-CB.1 cells are indeed endothelial progenitors and may prove to be an effective tool in regenerative medicine.

Insulin-Like Growth Factor Binding Protein 6 Is Secreted in Extracellular Vesicles upon Hyperthermia and Oxidative Stress in Dendritic Cells But Not in Monocytes

Recently, insulin-like growth factor binding protein 6 (IGFBP-6) has been shown to play a putative role in the immune system, as monocyte-derived dendritic cells (Mo-DCs) are stimulated by hyperthermia to express IGFBP-6 at both the mRNA and protein levels. However, the presence of IGFBP-6 in extracellular vesicles (EVs) and whether other pro-inflammatory stimuli can induce IGFBP-6 expression in Mo-DCs are not known yet. In this brief report, we show that hyperthermia (39 °C) induces IGFBP-6 secretion associated with microvesicles and exosomes as early as 3 h. Moreover, free IGFBP-6 is found in conditioned media (CM) of hyperthermia- and H₂O₂-treated Mo-DCs, but not in CM obtained from monocytes similarly treated. These results show that diverse inflammatory stimuli can induce IGFBP-6 association with EVs and secretion in conditioned medium, indicating a role for IGFBP-6 in communication between immune cells.

Depot-Specific Analysis of Human Adipose Cells and Their Responses to Bisphenol S

Exposure to endocrine-disrupting chemicals (EDCs) is associated with adverse health outcomes including obesity and diabetes. Obesity, and more specifically visceral obesity, is correlated with metabolic disease. The adipose tissue is an endocrine organ and a potential target for many environmental pollutants including bisphenols. The subcutaneous (Sc) and the omental (Om, visceral) depots are composed of mature adipocytes and residing progenitors, which may be different between the depots and may be EDCs targets. Bisphenol A (BPA) is a suspected metabolic disruptor, and is being replaced with structurally similar compounds such as bisphenol S (BPS). Like BPA, BPS induces adipogenesis in murine and primary human Sc preadipocytes. However, the effect of BPS on Om preadipocytes is not known. In this study, we show that human primary progenitors from Om depots have a distinct transcriptomic signature as compared to progenitors derived from donor-matched Sc depots. Furthermore, we show that BPS increases adipogenesis both of Om and Sc preadipocytes and can mimic the action of glucocorticoids or peroxisome proliferator-activated receptor γ (PPARγ) agonists. We also show that BPS treatment, at 0.1 µM and 25 µM, modifies the adipokine profiles both of Om- and Sc-derived adipocytes in a depot-specific manner. Taken together our data show distinct gene expression profiles in the Om vs Sc progenitors and similar responses to the BPA analogue, BPS.

Evaluating Vascularization of Heterotopic Islet Constructs for Type 1 Diabetes Using an In Vitro Platform

Type 1 diabetes (T1D) results from the autoimmune destruction of β-cells within the pancreatic islets of Langerhans. Clinical islet transplantation from healthy donors is proposed to ameliorate symptoms, improve quality of life, and enhance the life span of afflicted T1D patients. However, post-transplant outcomes are dependent on the survival of the transplanted islets, which relies on the engraftment of the islets with the recipient's vasculature among other factors. Treatment strategies to improve engraftment include combining islets with supporting cells including endothelial cells (EC) and mesenchymal stem cells (MSC), dynamic cells capable of robust immunomodulatory and vasculogenic effects. In this study, we developed an in vitro model of transplantation to investigate the cellular mechanisms that enhance rapid vascularization of heterotopic islet constructs. Self-assembled vascular beds of fluorescently stained EC served as reproducible in vitro transplantation sites. Heterotopic islet constructs composed of islets, EC, and MSC were transferred to vascular beds for modeling transplantation. Time-lapsed imaging was performed for analysis of the vascular bed remodeling for parameters of neo-vascularization. Moreover, sampling of media following modeled transplantation showed secretory profiles that were correlated with imaging analyses as well as with islet function using glucose-stimulated insulin secretion. Together, evidence revealed that heterotopic constructs consisting of islets, EC, and MSC exhibited the most rapid recruitment and robust branching of cells from the vascular beds suggesting enhanced neo-vascularization compared to islets alone and control constructs. Together, this evidence supports a promising cell transplantation strategy for T1D and also demonstrates a valuable tool for rapidly investigating candidate cellular therapies for transplantation.

Bioactive borate glass triggers phenotypic changes in adipose stem cells

A bioactive borate glass, 13-93B3 (B3), has been used successfully in the clinic to treat chronic, nonhealing wounds without scarring. However, the mechanism by which B3 stimulates wound healing is poorly understood. Because adipose stem cells (ASCs) have been shown to have multiple roles in wound repair, we hypothesized that B3 triggers ASCs. In this study, we evaluate the effects of B3 on ASC survival, migration, differentiation, and protein secretion in vitro. In concentrations ≤10 mg/ml, B3 did not affect ASC viability under static conditions. B3 promoted the migration of ASCs but did not increase differentiation into bone or fat. B3 also decreased ASCs secretion of collagen I, PAI-1, MCP-1, DR6, DKK-1, angiogenin, IL-1, IGFBP-6, VEGF, and TIMP-2; increased expression of IL-1R and E-selectin; had a transient decrease in IL-6 secretion; and had a transient increase in bFGF secretion. Together, these results show that B3 alters the protein secretion of ASCs.

Effects of food deprivation on plasma insulin-like growth factor-1 (Igf1) and Igf binding protein (Igfbp) gene transcription in juvenile cabezon (Scorpaenichthys marmoratus)

The growth hormone (GH)/insulin-like growth factor (Igf) endocrine axis regulates somatic growth in the face of changing environmental conditions. In actinopterygian fishes, food availability is a key modulator of the somatotropic axis, with lower food intake generally depressing liver Igf1 release to diminish growth. Igf1 signaling, however, also involves several distinct IGF binding proteins (Igfbps), and the functional roles of many of these Igfbps in affecting growth during shifting food availability remain uncertain. Here, we tested how complete food deprivation (fasting) affected gene transcription for paralogs of all six types of Igfbps in the liver and fast-twitch skeletal muscle of cabezon (Scorpaenichthys marmoratus), a nearshore marine fish important for recreational fisheries in the eastern North Pacific Ocean. Juvenile cabezon were maintained as either fed (6% mass food⋅g fish wet mass^-1⋅d^-1) or fasted for 14 d. Fasted fish exhibited a lower body condition (K), a depressed mass-specific growth rate (SGR), and reduced plasma concentrations of Igf1. In the liver, fasting reduced the relative abundance of gene transcripts encoding Igfbps igfbp2a and igfbp2b, while significantly elevating mRNA levels for igfbp1a, igfbp1b, igfbp3b, and igfbp4. Fasting also reduced hepatic mRNA levels of GH receptor-1 (ghr1) - but not GH receptor-2 (ghr2) - supporting the idea that changes in liver sensitivity to GH may underlie the decline in plasma Igf1 during food deprivation. In skeletal muscle, fasting downregulated gene transcripts encoding igf1, igfbp2b, igfbp5b, and igfbp6b, while also upregulating mRNAs for igf2 and ghr2. These data demonstrate isoform-specific regulation of Igfbps in liver and skeletal muscle in cabezon experiencing food deprivation and reinforce the idea that the repertoire of duplicated Igfbp genes that evolved in actinopterygian fishes supports a diverse scope of endocrine and paracrine functions.

Effect of Inhibition of Colony-Stimulating Factor 1 Receptor on Choroidal Neovascularization in Mice

Neovascular age-related macular degeneration is one of the leading causes of blindness. Microglia and macrophages play a critical role in choroidal neovascularization (CNV) and may, therefore, be potential targets to modulate the disease course. This study evaluated the effect of the colony-stimulating factor-1 receptor inhibitor PLX5622 on experimental laser-induced CNV. A 98% reduction of retinal microglia cells was observed in the retina 1 week after initiation of PLX5622 treatment, preventing accumulation of macrophages within the laser site and leading to a reduction of leukocytes within the choroid after CNV induction. Mice treated with PLX5622 had a significantly faster decrease of the CNV lesion size, as revealed by in vivo imaging and immunohistochemistry from day 3 to day 14 compared with untreated mice. Several inflammatory modulators, such as chemokine (C-C motif) ligand 9, granulocyte-macrophage colony-stimulating factor, soluble tumor necrosis factor receptor-I, IL-1α, and matrix metallopeptidase-2, were elevated in the acute phase of the disease when microglia were ablated with PLX5622, whereas other cytokines (eg, interferon-γ, IL-4, and IL-10) were reduced. Our results suggest that colony-stimulating factor-1 receptor inhibition may be a novel therapeutic target in patients with neovascular age-related macular degeneration.

A review of renal GH/IGF1 family gene expression in chronic kidney diseases

Despite decades of study on the contribution of growth hormone (GH) to the development of kidney disease, there remains the question of the relative contribution of elevated levels of GH to kidney damage in humans, particularly in diabetic nephropathy occurring in type 1 patients. In this study, we reviewed several publicly available datasets to examine transcription of twelve genes associated with the GH/IGF1 axis in several types of human and rodent kidney diseases. Our analyses revealed downregulation of renal GHR and IGF1 gene expression in several different chronic human kidney diseases, including diabetic nephropathy, with general upregulation of IGFBP6 in the same tissues and diseases. These findings were generally supported by a review of studies in rodent models. In healthy and diseased human kidneys, increased GHR gene expression was associated with increases in glomerular filtration rate (GFR) and decreases in serum creatinine. IGFBP6 gene expression demonstrated the opposite clinical correlation. Our results suggest the kidney may exhibit GH insensitivity due to low GHR gene expression during most chronic kidney diseases.

HDAC7-mediated control of tumour microenvironment maintains proliferative and stemness competence of human mammary epithelial cells

HDAC7 is a pleiotropic transcriptional coregulator that controls different cellular fates. Here, we demonstrate that in human mammary epithelial cells, HDAC7 sustains cell proliferation and favours a population of stem-like cells, by maintaining a proficient microenvironment. In particular, HDAC7 represses a repertoire of cytokines and other environmental factors, including elements of the insulin-like growth factor signalling pathway, IGFBP6 and IGFBP7. This HDAC7-regulated secretome signature predicts negative prognosis for luminal A breast cancers. ChIP-seq experiments revealed that HDAC7 binds locally to the genome, more frequently distal from the transcription start site. HDAC7 can colocalize with H3K27-acetylated domains and its deletion further increases H3K27ac at transcriptionally active regions. HDAC7 levels are increased in RAS-transformed cells, in which this protein was required not only for proliferation and cancer stem-like cell growth, but also for invasive features. We show that an important direct target of HDAC7 is IL24, which is sufficient to suppress the growth of cancer stem-like cells.

Insulin-like growth factor binding proteins and angiogenesis: from cancer to cardiovascular disease

Angiogenesis is a tightly regulated activity that is vital during embryonic development and for normal physiological repair processes and reproduction in healthy adults. Pathological angiogenesis is a driving force behind a variety of diseases including cancer and retinopathies, and inhibition of angiogenesis is a therapeutic option that has been the subject of much research, with several inhibitory agents now available for medical therapy. Conversely, therapeutic angiogenesis has been mooted as having significant potential in the treatment of ischemic conditions such as angina pectoris and peripheral arterial disease, but so far there has been less translation from lab to bedside. The insulin-like growth factor binding proteins (IGFBP) are a family of seven proteins essential for the binding and transport of the insulin-like growth factors (IGF). It is being increasingly recognised that IGFBPs have a significant role beyond simply modulating IGF activity, with evidence of both IGF dependent and independent actions through a variety of mechanisms. Moreover, the action of the IGFBPs can be stimulatory or inhibitory depending on the cell type and environment. Specifically the IGFBPs have been heavily implicated in angiogenesis, both pathological and physiological, and they have significant promise as targeted cell therapy agents for both pathological angiogenesis inhibition and therapeutic angiogenesis following ischemic injury. In this short review we will explore the current understanding of the individual impact of each IGFBP on angiogenesis, and the pathways through which these effects occur.

IGF-axis confers transformation and regeneration of fallopian tube fimbria epithelium upon ovulation

Background

The fallopian tube fimbria is regarded as the main tissue of origin and incessant ovulation as the main risk factor of ovarian high-grade serous carcinoma. Previously, we discovered the tumorigenesis activity of human ovulatory follicular fluid (FF) upon injection to the mammary fat pad of Trp53-null mice. We also found a mutagenesis activity of FF-ROS and a apoptosis-rescuing activity of Hb from retrograde menstruation. However, neither of them can explain the tumorigenesis activities of FF.

Methods

From two cohorts of ovulatory FF retrieved from IVF patients, the main growth factor responsible for the transformation of human fimbrial epithelial cells was identified. Mechanism of activation, ways of signal transduction of the growth factor, as well as the cellular and genetic phenotypes of the malignant transformation was characterized.

Findings

In this study, we showed that insulin-like growth factor (IGF)-axis proteins, including IGFBP-bound IGF2 as well as the IGFBP-lytic enzyme PAPP-A, are abundantly present in FF. Upon engaging with glycosaminoglycans on the membrane of fimbrial epithelial cells, PAPP-A cleaves IGFBPs and releases IGF2 to bind with IGF-1R. Through the IGF-1R/AKT/mTOR and IGF-1R/AKT/NANOG pathways, FF-IGF leads to stemness and survival, and in the case of TP53/Rb or TP53/CCNE1 loss, to clonal expansion and malignant transformation of fimbrial epithelial cells. By depleting each IGF axis component from FF, we proved that IGF2, IGFBP2/6, and PAPP-A are all essential and confer the majority of the transformation and regeneration activities.

Interpretation

This study revealed that the FF–IGF axis functions to regenerate tissue damage after ovulation and promote the transformation of fimbrial epithelial cells that have been initiated by p53- and Rb-pathway disruptions.

Fund

The study was supported by grants of the Ministry of Science and Technology, Taiwan (MOST 106-2314-B-303-001-MY2; MOST 105-2314-B-303-017-MY2; MOST 107-2314-B-303-013-MY3), and Buddhist Tzu Chi General Hospital, Taiwan (TCMMP104-04-01).

Adipose Tissue Dysfunction Occurs Independently of Obesity in Adipocyte-Specific Oncostatin Receptor Knockout Mice

OBJECTIVE

This study examined the phenotypic effects of adipocyte-specific oncostatin M receptor (OSMR) loss in chow-fed mice.

METHODS

Chow-fed adipocyte-specific OSMR knockout (FKO) mice and littermate OSMR^fl/fl controls were studied. Tissue weights, insulin sensitivity, adipokine production, and stromal cell immunophenotypes were assessed in epididymal fat (eWAT); serum adipokine production was also assessed. In vitro, adipocytes were treated with oncostatin M, and adipokine gene expression was assessed.

RESULTS

Body weights, fasting blood glucose levels, and eWAT weights did not differ between genotypes. However, the eWAT of OSMR^FKO mice was modestly less responsive to insulin stimulation than that of OSMR^fl/fl mice. Notably, significant increases in adipokines, including C-reactive protein, lipocalin 2, intercellular adhesion molecule-1, and insulinlike growth factor binding protein 6, were observed in the eWAT of OSMR^FKO mice. In addition, significant increases in fetuin A and intercellular adhesion molecule-1 were detected in OSMR^FKO serum. Flow cytometry revealed a significant increase in leukocyte number and modest, but not statistically significant, increases in B cells and T cells in the eWAT of OSMR^FKO mice.

CONCLUSIONS

The chow-fed OSMR^FKO mice exhibited adipose tissue dysfunction and increased proinflammatory adipokine production. These results suggest that intact adipocyte oncostatin M-OSMR signaling is necessary for adipose tissue immune cell homeostasis.

From fever to immunity: A new role for IGFBP-6?

Fever is a fundamental response to infection and a hallmark of inflammatory disease, which has been conserved and shaped through millions of years of natural selection. Although fever is able to stimulate both innate and adaptive immune responses, the very nature of all the molecular thermosensors, the timing and the detailed mechanisms translating a physical trigger into a fundamental biological response are incompletely understood. Here we discuss the consequence of hyperthermic stress in dendritic cells (DCs), and how the sole physical input is sensed as an alert stimulus triggering a complex transition in a very narrow temporal window. Importantly, we review recent findings demonstrating the significant and specific changes discovered in gene expression and in the metabolic phenotype associated with hyperthermia in DCs. Furthermore, we discuss the results that support a model based on a thermally induced autocrine signalling, which rewires and sets a metabolism checkpoint linked to immune activation of dendritic cells. Importantly, in this context, we highlight the novel regulatory functions discovered for IGFBP‐6 protein: induction of chemotaxis; capacity to increase oxidative burst and degranulation of neutrophils, ability to induce metabolic changes in DCs. Finally, we discuss the role of IGFBP‐6 in autoimmune disease and how novel mechanistic insights could lead to exploit thermal stress‐related mechanisms in the context of cancer therapy.

IGFBP6 is a novel nasopharyngeal carcinoma prognostic biomarker

Insulin-like growth factor binding proteins (IGFBPs) play critical roles in carcinogenesis. This study assessed the impact of IGFBP6 on the progression of nasopharyngeal carcinoma (NPC). Using immunohistochemical analysis, we found that IGFBP6 was differentially expressed in primary malignant NPC tissues. Clinical samples were divided into two groups: IGFBP6(+) and IGFBP6(−). Five years of follow-up revealed that overall survival and distant metastasis-free survival rates were significantly higher in the IGFBP6(+) than IGFBP6(−) group. We also used real-time PCR, ELISA and western blot assays to measure IGFBP6 levels in five NPC cell lines (CNE1, CNE2, HONE1, HK1 and SUNE1). All the cell lines expressed IGFBP6, but at different levels, reflecting disease heterogeneity. In addition, exogenous expression of IGFBP6 inhibited CNE2 cell proliferation and invasion in vitro. IGFBP6 knockdown activated the GSK3β/β-catenin/cyclin D1 pathway and enhanced CNE2 tumor cell growth and metastasis in a mouse model. These results suggest that IGFBP6 may be an independent prognostic biomarker for NPC.

What Happened to the IGF Binding Proteins?

Insulinlike growth factor (IGF) binding proteins (IGFBPs) 1 to 6 are high-affinity regulators of IGF activity. They generally inhibit IGF actions by preventing binding to the IGF-I receptor but can also enhance their actions under some conditions. Posttranslational modifications such as glycosylation and phosphorylation modulate IGFBP properties, and IGFBP proteolysis results in IGF release. IGFBPs have more recently been shown to have IGF-independent actions. A number of mechanisms are involved, including modulation of other growth factor pathways, nuclear localization and transcriptional regulation, interaction with the sphingolipid pathway, and binding to non-IGF biomolecules in the extracellular space and matrix, on the cell surface and intracellularly. IGFBPs modulate important biological processes, including cell proliferation, survival, migration, senescence, autophagy, and angiogenesis. Their actions have been implicated in growth, metabolism, cancer, stem cell maintenance and differentiation, and immune regulation. Recent studies have shown that epigenetic mechanisms are involved in the regulation of IGFBP abundance. A more complete understanding of IGFBP biology is necessary to further define their cellular roles and determine their therapeutic potential.

IGF Binding Protein-5 Induces Cell Senescence

Cellular senescence is the complex process of deterioration that drives the aging of an organism, resulting in the progressive loss of organ function and eventually phenotypic aging. Senescent cells undergo irreversible growth arrest, usually by inducing telomere shortening. Alternatively, senescence may also occur prematurely in response to various stress stimuli, such as oxidative stress, DNA damage, or activated oncogenes. Recently, it has been shown that IGF binding protein-5 (IGFBP-5) with the induction of the tumor suppressor p53 is upregulated during cellular senescence. This mechanism mediates interleukin-6/gp130-induced premature senescence in human fibroblasts, irradiation-induced premature senescence in human endothelial cells (ECs), and replicative senescence in human ECs independent of insulin-like growth factor I (IGF-I) and IGF-II. Additionally, a link between IGFBP-5, hyper-coagulation, and inflammation, which occur with age, has been implicated. Thus, IGFBP-5 seems to play decisive roles in controlling cell senescence and cell inflammation. In this review, we describe the accumulating evidence for this role of IGFBP-5 including our new finding.

Insulin-Like Growth Factor-Binding Proteins of Teleost Fishes

The insulin-like growth factor (Igf) binding protein (Igfbp) family has a broad range of physiological functions and a fascinating evolutionary history. This review focuses on the Igfbps of teleost fishes, where genome duplication events have diversified gene repertoire, function, and physiological regulation-with six core Igfbps expanded into a family of over twenty genes in some lineages. In addition to briefly summarizing the current state of knowledge on teleost Igfbp evolution, function, and expression-level regulation, we highlight gaps in our understanding and promising areas for future work.

Insulin-like growth factor-6 (IGFBP-6) stimulates neutrophil oxidative burst, degranulation and chemotaxis

The aim of this study was to understand whether insulin-like growth factor-binding protein-6 (IGFBP-6) has functional effects on neutrophils, in particular when they cross epithelium during inflammation. We found that IGFBP-6 increased ROS production (cytofluorimetry), degranulation of primary and tertiary granules (ELISA) and transmigration through the epithelial monolayer. No priming by IGFBP-6 on neutrophils stimulated by either PMA or fMLP was observed. IGFBP-6 is an agonist of neutrophils' functions, most likely when these cells have been already activated by other stimuli.

Molecular insights into the transcriptional regulatory role of thyroid hormones in ovarian cancer

The regulation of cancer-relevant genes by the thyroid hormones, 3, 5, 3'-Triiodo-L-thyronine (T3) and L-thyroxine (T4), was recently acknowledged. However, limited data exists on the hormonal effects on gene expression in ovarian cancer, a gynecological malignancy associated with a low cure rate. The expression of fifteen genes involved in DNA repair, cell cycle, apoptosis, and tumor suppression was evaluated in OVCAR-3 and A2780 cell lines, using real-time PCR following short incubation with T3 (1 nM) or T4 (100 nM). The thyroid hormones downregulated the expression of the majority of genes examined. Support for the involvement of the MAPK and PI3K in thyroid hormone-mediated gene expression was shown for a set of genes. FAS expression was inhibited in A2780 cells, while an unexpected induction was demonstrated in OVCAR-3 cells. An analogous effect on the protein levels of FAS receptor and its soluble form was demonstrated by Western blotting. We further established, using primer sets that discriminate between the different RNA isoforms, that the hormones increase the mRNA levels of both coding and non-coding FAS mRNAs. The prevalence of these isoforms, using The Cancer Genome Atlas (TCGA) analysis, was significantly more abundant in 17 cancer types, including ovarian cancer, compared to normal tissues. Our results highlight the role of thyroid hormones in the expression of cancer-relevant-genes in ovarian cancer and provide an important insight into the pathways by which mitogenic and anti-apoptotic effects are exerted.

Insulin-like growth factor binding protein-6 released from human mesenchymal stem cells confers neuronal protection through IGF-1R-mediated signaling

Human bone marrow-derived mesenchymal stem cells (hMSCs) are a desirable cell source for cell-based therapy to treat nervous system injuries due to their ability to differentiate into specific cell types. In addition to their multi-potency, hMSCs render the tissue microenvironment more favorable for tissue repair by secreting various growth factors. Our previous study demonstrated that hMSCs secrete several growth factors, including several insulin-like growth factor binding proteins (IGFBPs). Among these, IGFBP-6 binds with high affinity and inhibits insulin growth factor-2 (IGF-2) to inhibit the growth of IGF-2-dependent tumors. However, the function of IGFBP-6 in the nervous system remains to be fully elucidated. The present study investigated the protective effects of IGFBP-6 secreted by hMSCs on H₂O₂-injured primary cortical neuron cultures and lysolecithin-injured organotypic spinal cord slice cultures. Treatment of the H₂O₂-injured cortical neurons with conditioned media from hMSCs (hMSC-CM) increased the phosphorylation of Akt, reduced cell death and mitochondrial translocation of Bax, and regulated extracellular levels of IGF-1 and IGF-2. MTT assay, western blot analysis and ELISA were used to detect the cell viability and protein expression levels, respectively. An inhibitory antibody against IGFBP-6 eliminated this hMSC-CM-mediated neuroprotective effect in the injured cortical neuron cultures and spinal cord slice cultures. In addition, treatment with cyclolignan picropodophyllin, an inhibitor of IGF-1 receptor (IGF-1R), significantly inhibited neuronal protection by hMSC-CM. These findings demonstrated that hMSC-CM-mediated neuroprotection was attributed to IGF-1R-mediated signaling, potentiated via the inhibition of IGF-2 by IGFBP-6. The results of the present study provide insight into the mechanism by which hMSC administration may promote recovery from nerve injury.

Insulin-Like Growth Factor Binding Protein 6 in Rheumatoid Arthritis: A Possible Novel Chemotactic Factor?

Objectives

Immune cell migration from the bloodstream to target tissues is a hallmark of rheumatoid arthritis (RA) pathogenesis. The role of chemoattractants, mainly chemokines, and their possible targeting for therapeutic purposes have been under intense investigation over the last few years but the results were not as satisfactory as expected. The insulin-like growth factor binding protein 6 (IGFBP6), a direct inhibitor of insulin-like growth factor (IGF)-II, also exerts IGF-independent effects including tumor cell migration in vitro. We aimed to assess the expression of this protein in serum, synovial fluid, and synovial tissue (ST) of RA patients and to identify its possible chemotactic role in this disorder.

Methods

IGFBP6 was measured in RA patients and healthy donors (HD) sera by Luminex xMAP^® technology and in ST of RA patients and osteoarthritis (OA) controls by immunofluorescence. The identification of circulating IGFBP6⁺ cells was evaluated by flow cytometry and an in vitro migration assay was arranged.

Results

We demonstrated that IGFBP6 is able to induce greater in vitro migration of RA as compared to HD and OA T lymphocytes and is overexpressed in serum and ST of RA patients. This in vitro chemotactic activity can be partially inhibited by dexamethasone.

Conclusion

Our findings suggest a pathogenic role of IGFBP6 in RA and support its possible targeting for therapeutic purposes.

Current ideas on the biology of IGFBP-6: More than an IGF-II inhibitor?

IGFBP-6 binds IGF-II with higher affinity than IGF-I and it is a relatively specific inhibitor of IGF-II actions. More recently, IGFBP-6 has also been reported to have IGF-independent effects on cell proliferation, survival, differentiation and migration. IGFBP-6 binds to several ligands in the extracellular space, cytoplasm and nucleus. These interactions, together with activation of distinct intracellular signaling pathways, may contribute to its IGF-independent actions; for example, IGF-independent migration induced by IGFBP-6 involves interaction with prohibitin-2 and activation of MAP kinase pathways. A major challenge for the future is delineating the relative roles of the IGF-dependent and -independent actions of IGFBP-6, which may lead to the development of therapeutic approaches for diseases including cancer.

IGFBP6 Regulates Cell Apoptosis and Migration in Glioma

The insulin-like growth factor binding protein 6 (IGFBP6), as an inhibitor of IGF-II actions, plays an important role in inhibiting survival and migration of tumor cells. In our study, we intended to demonstrate the biological function of IGFBP6 in the development of glioma and its clinical significance. Firstly, Western blot and immunohistochemistry revealed that the expression of IGFBP6 inversely correlated with glioma grade. Secondly, multivariate analysis with the Cox proportional hazards model and Kaplan-Meier analysis indicated that IGFBP6 could be an independent prognostic factor for the survival of glioma patients. In addition, overexpression of IGFBP6 induced glioma cell apoptosis, and depletion of IGFBP6 had the opposite action. Finally, overexpression of IGFBP6 inhibited migration of glioma cells, and depletion of IGFBP6 had the opposite action. Together our findings suggest that IGFBP6 might be an important regulator and prognostic factor for glioma.

Cross Talk Between Growth and Immunity: Coupling of the IGF Axis to Conserved Cytokine Pathways in Rainbow Trout

Although disease and infection is associated with attenuated growth, the molecular pathways involved are poorly characterized. We postulated that the IGF axis, a central governor of vertebrate growth, is repressed during infection to promote resource reallocation towards immunity. This hypothesis was tested in rainbow trout (Oncorhynchus mykiss) challenged by Aeromonas salmonicida (AS), a Gram-negative bacterial pathogen, or viral hemorrhagic septicemia virus (VHSv) at hatch, first feeding, and 3 weeks after first feeding. Quantitative transcriptional profiling was performed for genes encoding both IGF hormones, 19 salmonid IGF binding proteins (IGFBPs) and a panel of marker genes for growth and immune status. There were major differences in the developmental response of the IGF axis to AS and VHSv, with the VHSv challenge causing strong down-regulation of many genes. Despite this, IGFBP-1A1 and IGFBP-6A2 subtypes, each negative regulators of IGF signaling, were highly induced by AS and VHSv in striking correlation with host defense genes regulated by cytokine pathways. Follow-up experiments demonstrated a highly significant coregulation of IGFBP-1A1 and IGFBP-6A2 with proinflammatory cytokine genes in primary immune tissues (spleen and head kidney) when trout were challenged by a different Gram-negative bacterium, Yersinia ruckeri. Based on our findings, we propose a model where certain IGFBP subtypes are directly regulated by cytokine signaling pathways, allowing immediate modulation of growth and/or immune system phenotypes according to the level of activation of immunity. Our findings provide new and comprehensive insights into cross talk between conserved pathways regulating teleost growth, development, and immunity.