Elevated expression of angiomodulin (AGM/IGFBP-rP1) in tumor stroma and its roles in fibroblast activation

Angiogenesis modulated by CD93 and its natural ligands IGFBP7 and MMRN2: a new target to facilitate solid tumor therapy by vasculature normalization

The tumor vasculature was different from the normal vasculature in both function and morphology, which caused hypoxia in the tumor microenvironment (TME). Previous anti-angiogenesis therapy had led to a modest improvement in cancer immunotherapy. However, antiangiogenic therapy only benefitted a few patients and caused many side effects. Therefore, there was still a need to develop a new approach to affect tumor vasculature formation. The CD93 receptor expressed on the surface of vascular endothelial cells (ECs) and its natural ligands, MMRN2 and IGFBP7, were now considered potential targets in the antiangiogenic treatment because recent studies had reported that anti-CD93 could normalize the tumor vasculature without impacting normal blood vessels. Here, we reviewed recent studies on the role of CD93, IGFBP7, and MMRN2 in angiogenesis. We focused on revealing the interaction between IGFBP7-CD93 and MMRN2-CD93 and the signaling cascaded impacted by CD93, IGFBP7, and MMRN2 during the angiogenesis process. We also reviewed retrospective studies on CD93, IGFBP7, and MMRN2 expression and their relationship with clinical factors. In conclusion, CD93 was a promising target for normalizing the tumor vasculature.

Comprehensive Analysis of IGFBPs as Biomarkers in Gastric Cancer

OBJECTIVE

Gastric cancer is the fifth most common cancer worldwide and the third leading cause of cancer-related deaths. Insulin-like growth-factor-binding proteins (IGFBPs) were initially identified as passive inhibitors that combined with insulin-like growth factors (IGFs) in serum. However, more recent data have shown that they have different expression patterns and a variety of functions in the development and occurrence of cancers. Thus, their various roles in cancer still need to be elucidated. This study aimed to explore the IGFBPs and their prognostic value as markers in gastric cancer.

METHODS

Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier Plotter, cBioPortal, GeneMANIA, and TIMER were used to analyze the differential expression, prognostic value, genetic alteration, and association with immune cell infiltration of IGFPBs in gastric cancer.

RESULTS

Expression levels of IGFBP3, IGFBP4, and IGFBP7 were significantly elevated in gastric cancer tissues, whereas those of IGFBP1 were reduced in normal tissues. IGFBP1/5/7 expression was significantly associated with overall survival whereas IGFBP6/7 expression was significantly correlated with disease-free survival in gastric cancer patients. IGFBP3/5/6/7 were associated with clinical cancer stage. Gene ontology and Kyoto Encyclopedia of Genes and Genome analyses showed that IGFBP3/5/7 were mainly enriched in focal adhesion, extracellular matrix structural constituent, cell-substratist junction, extracellular structure, and matrix organization. Stomach adenocarcinoma (STAD) and gastric cancer had more IGFBP1-7 mutations than other tumor types. Hub gene analysis showed that TP53 and IGF2 expression was significantly elevated in STAD patients; PLG, PAPPA, AFP, and CYR61 were associated with overall survival rate; and IGFALS, PLG, IGF1, AHSG, and FN1 were associated with disease-free survival. Finally, IGFBP3-7 were all associated with cancer-associated fibroblast infiltration in STAD, colon adenocarcinoma, and rectal adenocarcinoma.

CONCLUSION

Our study provides a comprehensive analysis and selection of IGFBPs as prognostic biomarkers in STAD. This was the first bioinformatic analysis study to describe the involvement of IGFBPs, especially IGFBP7, in gastric cancer development through the extracellular matrix.

Targeting epigenetically maladapted vascular niche alleviates liver fibrosis in nonalcoholic steatohepatitis

[Figure: see text].

Secretome Analysis of Inductive Signals for BM-MSC Transdifferentiation into Salivary Gland Progenitors

Severe dry mouth in patients with Sjögren's Syndrome, or radiation therapy for patients with head and neck cancer, significantly compromises their oral health and quality of life. The current clinical management of xerostomia is limited to palliative care as there are no clinically-proven treatments available. Previously, our studies demonstrated that mouse bone marrow-derived mesenchymal stem cells (mMSCs) can differentiate into salivary progenitors when co-cultured with primary salivary epithelial cells. Transcription factors that were upregulated in co-cultured mMSCs were identified concomitantly with morphological changes and the expression of acinar cell markers, such as α-amylase (AMY1), muscarinic-type-3-receptor(M3R), aquaporin-5(AQP5), and a ductal cell marker known as cytokeratin 19(CK19). In the present study, we further explored inductive molecules in the conditioned media that led to mMSC reprogramming by high-throughput liquid chromatography with tandem mass spectrometry and systems biology. Our approach identified ten differentially expressed proteins based on their putative roles in salivary gland embryogenesis and development. Additionally, systems biology analysis revealed six candidate proteins, namely insulin-like growth factor binding protein-7 (IGFBP7), cysteine-rich, angiogenetic inducer, 61(CYR61), agrin(AGRN), laminin, beta 2 (LAMB2), follistatin-like 1(FSTL1), and fibronectin 1(FN1), for their potential contribution to mMSC transdifferentiation during co-culture. To our knowledge, our study is the first in the field to identify soluble inductive molecules that drive mMSC into salivary progenitors, which crosses lineage boundaries.

Insulin-like growth factor-binding protein 7 (IGFBP7): Novel, independent marker of cardiometabolic diseases?

Insulin-like growth factor-binding protein 7 (IGFBP7) is a 30kDa modular secreted protein involved in many physiologic processes, including cell proliferation, adhesion, senescence and angiogenesis. It is expressed in many organs and specific cells. It can interact with insulin-like growth factor 1(IGF-1), as well as with insulin. By binding to IGF-1, it limits IGF-1 access to IGF- receptor (IGF-R) and consequently neutralizes IGF-1 activity. Moreover, due to its high affinity to insulin, it may interfere with biological response of insulin and, therefore, it may be involved in the development of diabetes and cardiovascular diseases. According to research, it could be a good biomarker of heart failure. Its elevated serum concentrations were found in patients with heart failure, both with reduced ejection fraction and preserved ejection fraction. Moreover, IGFBP7 could be useful in predicting the presence of atherosclerotic lesions in coronary vessels, although its concentration does not reflect a degree of coronary artery disease (CAD) advancement and it cannot be used as a marker of acute ischemia. Its concentration is also associated with insulin resistance and the risk of metabolic syndrome. What is more, together with tissue inhibitor of metalloproteinases-2, it is a novel marker of tubular damage and it can be used for an early detection of acute kidney injury (AKI) endangered patients, which could allow for subsequent adjustments in medical therapy and the prevention of AKI. IGFBP7 is also regarded as a potential tumor suppressor in various cancers. Its low expression is potentially correlated with increased cancer cell proliferation.

Cancer-associated fibroblast regulation of tumor neo-angiogenesis as a therapeutic target in cancer

Adequate blood supply is essential for tumor survival, growth and metastasis. The tumor microenvironment (TME) is dynamic and complex, comprising cancer cells, cancer-associated stromal cells and their extracellular products. The TME serves an important role in tumor progression. Cancer-associated fibroblasts (CAFs) are the principal component of stromal cells within the TME, and contribute to tumor neo-angiogenesis by altering the proteome and degradome. The present paper reviews previous studies of the molecular signaling pathways by which CAFs promote tumor neo-angiogenesis and highlights therapeutic response targets. Also discussed are potential strategies for antitumor neo-angiogenesis to improve tumor treatment efficacy.

Cancer cell migration on elongate protrusions of fibroblasts in collagen matrix

Cancer-associated fibroblasts (CAFs) play critical roles in the tumor progression. However, it remains unclear how cancer cells migrate in the three-dimensional (3D) matrix of cancer tissues and how CAFs support the cancer invasion. Here we propose a novel mechanism of fibroblast-dependent cancer cell invasion in the 3D collagen matrix. Human cancer cell lines from the pancreas (Panc-1), lung (A549) and some other organs actively adhered to normal fibroblasts and primary lung CAFs in cultures. To show its significance in tumor invasion, we designed a new invasion assay in which homogeneous microspheroids consisting of cancer cells and fibroblasts were embedded into collagen gel. Time-lapse experiments showed that cancer cells adhered to and quickly migrated on the long protrusions of fibroblasts in the 3D collagen matrix. Fibroblast-free cancer cells poorly invaded the matrix. Experiments with function-blocking antibodies, siRNAs, and immunocytochemistry demonstrated that cancer cells adhered to fibroblasts through integrin α5β1-mediated binding to fibronectin on the surface of fibroblasts. Immunochemical analyses of the co-cultures and lung cancers suggested that cancer cells could acquire the migratory force by the fibronectin/integrin signaling. Our results also revealed that the fibroblast-bound fibronectin was a preferential substrate for cancer cells to migrate in the collagen matrix.

Comparison of Prognostic Usefulness of Serum Insulin-Like Growth Factor-Binding Protein 7 in Patients With Heart Failure and Preserved Versus Reduced Left Ventricular Ejection Fraction

We aimed to characterize of the role of insulin-like growth factor-binding protein 7 (IGFBP-7) in heart failure (HF) pathophysiology. IGFBP-7 has been associated with cardiac hypertrophy and diastolic dysfunction in HF. In 86 patients with HF with a preserved ejection fraction (HFpEF) (ejection fraction [EF] ≥45%) and 79 with HF with a reduced ejection fraction (HFrEF), we assessed concentrations of serum IGFBP-7, correlations between serum IGFBP-7 and clinical data, diastolic function, and associations with outcome. IGFBP-7 was lower in HFpEF than HFrEF (102 vs 152 µg/L, p <0.001) and correlated with New York Heart Association class (HFpEF: r = 0.25, p = 0.020; HFrEF: r = 0.26, p = 0.022), N-terminal pro-brain natriuretic peptide (NT-proBNP) (HFpEF: r = 0.53, p <0.001; HFrEF: r = 0.50, p <0.001), and estimated glomerular filtration rate (eGFR) (HFpEF: r = -0.47, p <0.001; HFrEF: r = -0.45, p <0.001). In HFpEF, IGFBP-7 correlated with E/e' (r = 0.31, p = 0.012) and E/A ratio (r = 0.31, p = 0.011). In HFrEF, but not HFpEF, IGFBP-7 correlated with age (r = 0.29, p = 0.009) and atrial fibrillation (r = 0.34, p = 0.002). IGFBP-7 predicted the outcome in HFpEF (hazard ratio 4.19 [1.01 to 17.35], p = 0.048]) but not in HFrEF (0.72 [0.24 to 2.14], p = 0.554). In conclusion in HFrEF, IGFBP-7 was elevated and associated with HF severity but not prognostic, suggesting a marker of risk. In HFpEF, IGFBP-7 was less elevated but associated with markers of diastolic dysfunction, HF severity, and prognosis. IGFBP-7 may contribute to the progression of HFpEF possibly through inflammation and oxidative stress.

Interaction between insulin-like growth factor binding protein-related protein 1 and transforming growth factor beta 1 in primary hepatic stellate cells

BACKGROUND

We previously showed that insulin-like growth factor binding protein-related protein 1 (IGFBPrP1) is a novel mediator in liver fibrosis. Transforming growth factor beta 1 (TGFβ1) is known as the strongest effector of liver fibrosis. Therefore, we aimed to investigate the detailed interaction between IGFBPrP1 and TGFβ1 in primary hepatic stellate cells (HSCs).

METHODS

We overexpressed TGFβ1 or IGFBPrP1 and inhibited TGFβ1 expression in primary HSCs for 6, 12, 24, 48, 72, and 96 hours to investigate their interaction and observe the accompanying expressions of α-smooth muscle actin (α-SMA), collagen I, fibronectin, and phosphorylated-mothers against decapentaplegic homolog 2/3 (p-Smad2/3).

RESULTS

We found that the adenovirus vector encoding the TGFβ1 gene (AdTGFβ1) induced IGFBPrP1 expression while that of α-SMA, collagen I, fibronectin, and TGFβ1 increased gradually. Concomitantly, AdIGFBPrP1 upregulated TGFβ1, α-SMA, collagen I, fibronectin, and p-Smad2/3 in a time-dependent manner while IGFBPrP1 expression was decreased at 96 hours. Inhibition of TGFβ1 expression reduced the IGFBPrP1-stimulated expression of α-SMA, collagen I, fibronectin, and p-Smad2/3.

CONCLUSIONS

These findings for the first time suggest the existence of a possible mutually regulation between IGFBPrP1 and TGFβ1, which likely accelerates liver fibrosis progression. Furthermore, IGFBPrP1 likely participates in liver fibrosis in a TGFβ1-depedent manner, and may act as an upstream regulatory factor of TGFβ1 in the Smad pathway.

Prognostic Value of Insulin-Like Growth Factor-Binding Protein 7 in Patients with Heart Failure and Preserved Ejection Fraction

BACKGROUND

The prognostic merit of insulin-like growth factor-binding protein 7 (IGFBP7) is unknown in heart failure and preserved ejection fraction (HFpEF).

METHODS AND RESULTS

Baseline IGFBP7 (BL-IGFBP7; n = 302) and 6-month change (Δ; n = 293) were evaluated in the Irbesartan in Heart Failure and Preserved Ejection Fraction (I-PRESERVE) trial. Primary outcome was all-cause mortality or cardiovascular hospitalization with median follow-up of 3.6 years; secondary outcomes included HF events. Median BL-IGFBP7 concentration was 218 ng/mL. BL-IGFBP7 was significantly correlated with age (R² = 0.13; P < .0001), amino-terminal pro-B-type NP (R² = 0.22; P < .0001), and estimated glomerular filtration rate (eGFR; R² = 0.14; P < .0001), but not with signs/symptoms of HFpEF. BL-IGFBP7 was significantly associated with the primary outcome (hazard ratio [HR] = 1.007 per ng/mL; P < .001), all-cause mortality (HR = 1.008 per ng/mL; P < .001), and HF events (HR = 1.007 per ng/mL; P < .001). IGFBP7 remained significant for each outcome after adjustment for ln amino-terminal pro-B-type NP and eGFR but not all variables in the I-PRESERVE prediction model. After 6 months, IGFBP7 did not change significantly in either treatment group. ΔIGFBP7 was significantly associated with decrease in eGFR in patients randomized to irbesartan (R² = 0.09; P = .002). ΔIGFBP7 was not independently associated with outcome.

CONCLUSIONS

Higher concentrations of IGFBP7 were associated with increased risk of cardiovascular events, but after multivariable adjustment this association was no longer present. Further studies of IGFBP7 are needed to elucidate its mechanism.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov, NCT00095238.

Insulin-like growth factor binding protein-related protein 1 (IGFBPrP1) contributes to liver inflammation and fibrosis via activation of the ERK1/2 pathway

BACKGROUND AND AIM

Previously, we suggested that IGFBPrP1 played a major role in hepatic stellate cell (HSC) activation, yet the molecular mechanism of IGFBPrP1 in hepatic fibrosis is unclear. The ERK pathway is involved in activation of HSCs. This study investigated the involvement of the ERK1/2 pathway in IGFBPrP1-induced liver inflammation and fibrosis.

METHODS

An adenoviral vector encoding IGFBPrP1 (AdIGFBPrP1) was constructed. Rats received AdIGFBPrP1 or CAd (vector control) via their tail vein injection. One hour prior to adenoviral injections, rats were intraperitoneally administrated with 10 mg/kg U0126 (a specific MEK/ERK1/2 inhibitor) or DMSO (vehicle control). At weeks 2 or 4 post-gene transduction, serum samples were obtained and the levels of liver enzymes and hydroxyproline were determined. Liver tissue were histologically evaluated for inflammation and fibrosis. The expression of α-SMA and ECM were evaluated by qRT-PCR and western blotting.

RESULTS

After transduction, IGFBPrP1 expression significantly increased in livers and transduced cells. MEK/ERK1/2 inhibition administration of AdIGFBPrP1-treated rats and cells significantly blocked AdIGFBPrP1-induced activation of ERK1/2. U0126 significantly down-regulated the number of F4/80-positive cells and CD3-positive cells (markers of liver inflammation), the expression of α-SMA and the concentration of ECM components in vivo. In addition, α-SMA and TGF-β1 levels in AdIGFBPrP1 HSCs were markedly inhibited by a MEK/ERK1/2 inhibitor, indicating that HSC activation was inhibited.

CONCLUSION

These findings suggest that IGFBPrP1 acts as an initiator of liver fibrosis by inducing inflammation, HSC activation and ECM deposition through the ERK1/2 pathway.

IGFBPrP1 induces liver fibrosis by inducing hepatic stellate cell activation and hepatocyte apoptosis via Smad2/3 signaling

AIM: To investigate the role and mechanism of insulin-like growth factor binding protein-related protein 1 (IGFBPrP1) in the development of liver fibrosis.

METHODS: An in vitro model using hepatic stellate cell (HSC)-T6 cells and an in vivo model of rat liver overexpressing IGFBPrP1 were established using an IGFBPrP1-expressing recombinant adenovirus. The expression of IGFBPrP1 was examined by immunofluorescence, and the expression of collagen I and fibronectin was measured by real-time reverse transcription-polymerase chain reaction and Western blot analysis. The expression of Smad2/3 and p-Smad2/3 was examined by Western blot and immunohistochemistry. A shSmad3-expressing recombinant adenovirus (AdshSmad3) was designed and used to knockdown the Smad3 gene in HSC-T6 cells and rat liver fibrosis transfected with IGFBPrP1. The expression of collagen I, fibronectin, and α-smooth muscle actin (α-SMA) was determined by Western blot analysis and immunohistochemistry. Hepatocyte apoptosis was assessed using TUNEL assay.

RESULTS: IGFBPrP1 overexpression induced collagen deposition and up-regulated the expression of α-SMA and p-Smad2/3, and AdshSmad3 inhibited IGFBPrP1-stimulated p-Smad2/3 activation and the expression of α-SMA, collagen I and fibronectin in HSC-T6 cells. Similarly, increased hepatocyte apoptosis (38.56% ± 3.42% vs 0.24% ± 0.03%, P < 0.05), α-SMA positive stained cells (29.84% ± 1.36% vs 5.83% ± 1.47%, P < 0.05), and increased numbers of Smad3 (35.88% ± 2.15% vs 10.24% ± 1.31%, P < 0.05) and p-Smad2/3 positive cells (28.87% ± 2.73% vs 8.23% ± 0.98%, P < 0.05) were detected in the livers of IGFBPrP1-overexpressing rats compared with the control group. Moreover, AdshSmad3 reduced IGFBPrP1-stimulated Smad3 expression and attenuated α-SMA expression (29.84% ± 1.36% vs 8.23% ± 1.28%, P < 0.05), hepatocyte apoptosis (38.56% ± 3.42% vs 6.75% ± 0.52%, P < 0.05), and both collagen I and fibronectin deposition in the livers of AdIGFBPrP1-treated rats.

CONCLUSION: IGFBPrP1 induces liver fibrosis by mediating the activation of hepatic stellate cells and hepatocyte apoptosis in a Smad3-dependent mechanism.

Angiomodulin, a marker of cancer vasculature, is upregulated by vascular endothelial growth factor and increases vascular permeability as a ligand of integrin αvβ3

Angiomodulin (AGM) is a member of insulin-like growth factor binding protein (IGFBP) superfamily and often called IGFBP-rP1 or IGFBP-7. AGM was originally identified as a tumor-derived cell adhesion factor, which was highly accumulated in blood vessels of human cancer tissues. AGM is also overexpressed in cancer-associated fibroblasts (CAFs) and activates fibroblasts. However, some studies have shown tumor-suppressing activity of AGM. To understand the roles of AGM in cancer progression, we here investigated the expression of AGM in benign and invasive breast cancers and its functions in cancer vasculature. Immunohistochemical analysis showed that AGM was highly expressed in cancer vasculature even in ductal carcinoma in situ (DCIS) as compared to normal vasculature, while its expression in CAFs was more prominent in invasive carcinomas than DCIS. In vitro analyses showed that AGM was strongly induced by vascular endothelial cell growth factor (VEGF) in vascular endothelial cells. Although AGM stimulated neither the growth nor migration of endothelial cells, it supported efficient adhesion of endothelial cells. Integrin αvβ3 was identified as a novel major receptor for AGM in vascular endothelial cells. AGM retracted endothelial cells by inducing actin stress fibers and loosened their VE-cadherin-mediated intercellular junction. Consequently, AGM increased vascular permeability both in vitro and in vivo. Furthermore, AGM and integrin αvβ3 were highly expressed and colocalized in cancer vasculature. These results suggest that AGM cooperates with VEGF to induce the aberrant functions of cancer vasculature as a ligand of integrin αvβ3.

Insulin-like growth factor binding protein-related protein 1 and cancer

Insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1) belongs to the IGFBP family whose members have a conserved structural homology. It has a low affinity for IGFs and a high affinity for insulin, suggesting that IGFBP-rP1 may have a biological function distinct from other members of the family. IGFBP-rP1 is ubiquitously expressed in normal human tissues and has diverse biological functions, regulating cell proliferation, apoptosis and senescence; it may also have a key role in vascular biology. Increasing evidence suggests that IGFBP-rP1 acts as a tumor suppressor. It elicits its biological effects by both insulin/IGF-dependent and -independent mechanisms. This paper provides a brief overview of the structure and regulation of IGFBP-rP1 and its various biological functions in cancer, as well as the underlying molecular mechanisms.

Mammary epithelial cell interactions with fibronectin stimulate epithelial-mesenchymal transition

In the mammary gland, the stromal extracellular matrix (ECM) undergoes dramatic changes during development and in tumorigenesis. For example, normal adult breast tissue is largely devoid of the ECM protein fibronectin (FN) whereas high FN levels have been detected in the stroma of breast tumors. FN is an established marker for epithelial-mesenchymal transition (EMT), which occurs during development and has been linked to cancer. During EMT, epithelial cell adhesion switches from cell-cell contacts to mainly cell-ECM interactions raising the possibility that FN may have a role in promoting this transition. Using MCF-10A mammary epithelial cells, we show that exposure to exogenous FN induces an EMT response including up-regulation of the EMT markers FN, Snail, N-cadherin, vimentin, the matrix metalloprotease MMP2, α-smooth muscle actin, and phospho-Smad2 as well as acquisition of cell migratory behavior. FN-induced EMT depends on Src kinase and ERK/MAP kinase signaling but not on the immediate early gene EGR-1. FN initiates EMT under serum-free conditions; this response is partially reversed by a TGFβ neutralizing antibody suggesting that FN enhances the effect of endogenous TGFβ. EMT marker expression is up-regulated in cells on a fragment of FN containing the integrin-binding domain but not other domains. Differences in gene expression between FN and MG are maintained with addition of a sub-threshold level of TGFβ1. Together, these results show that cells interacting with FN are primed to respond to TGFβ. The ability of FN to induce EMT shows an active role for the stromal ECM in this process and supports the notion that the increased levels of FN observed in breast tumors facilitate tumorigenesis.