Intermedin is overexpressed in hepatocellular carcinoma and regulates cell proliferation and survival

Multi-biological functions of intermedin in diseases

Intermedin (IMD) is a member of the calcitonin gene-related peptide (CGRP)/calcitonin (CT) superfamily, and it is expressed extensively throughout the body. The typical receptors for IMD are complexes composed of calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein (RAMP), which leads to a biased activation towards Gαs. As a diagnostic and prognostic biomarker, IMD regulates the initiation and metastasis of multiple tumors. Additionally, IMD functions as a proangiogenic factor that can restrain excessive vascular budding and facilitate the expansion of blood vessel lumen, ultimately resulting in the fusion of blood vessels. IMD has protective roles in various diseases, including ischemia-reperfusion injury, metabolic disease, cardiovascular diseases and inflammatory diseases. This review systematically elucidates IMD's expression, structure, related receptors and signal pathway, as well as its comprehensive functions in the context of acute kidney injury, obesity, diabetes, heart failure and sepsis. However, the precise formation process of IMD short peptides in vivo and their downstream signaling pathway have not been fully elucidated yet. Further in-depth studies are need to translate IMD research into clinical applications.

Adrenomedullin2 stimulates progression of thyroid cancer in mice and humans under nutrient excess conditions

Thyroid cancer is associated with genetic alterations, e.g. BRAF^V600E , which may cause carcinomatous changes in hormone-secreting epithelial cells. Epidemiological studies have shown that overnutrition is related to the development and progression of cancer. In this study, we attempted to identify the cell nonautonomous factor responsible for the progression of BRAF^V600E thyroid cancer under overnutrition conditions. We developed a mouse model for inducible thyrocyte-specific activation of BRAF^V600E , which showed features similar to those of human papillary thyroid cancer. LSL-Braf^V600E ;TgCreER^T2 showed thyroid tumour development in the entire thyroid, and the tumour showed more abnormal cellular features with mitochondrial abnormalities in mice fed a high-fat diet (HFD). Transcriptomics revealed that adrenomedullin2 (Adm2) was increased in LSL-Braf^V600E ;TgCreER^T2 mice fed HFD. ADM2 was upregulated on the addition of a mitochondrial complex I inhibitor or palmitic acid with integrated stress response (ISR) in cancer cells. ADM2 stimulated protein kinase A and extracellular signal-regulated kinase in vitro. The knockdown of ADM2 suppressed the proliferation and migration of thyroid cancer cells. We searched The Cancer Genome Atlas and Genotype-Tissue Expression databases and found that increased ADM2 expression was associated with ISR and poor overall survival. Consistently, upregulated ADM2 expression in tumour cells and circulating ADM2 molecules were associated with aggressive clinicopathological parameters, including body mass index, in thyroid cancer patients. Collectively, we identified that ADM2 is released from cancer cells under mitochondrial stress resulting from overnutrition and acts as a secretory factor determining the progressive properties of thyroid cancer. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Intermedin (adrenomedullin 2) promotes breast cancer metastasis via Src/c-Myc-mediated ribosome production and protein translation

PURPOSE

Breast cancer is the most frequently diagnosed cancer and is the leading cause of cancer-associated mortality in women worldwide. Intermedin (IMD, also known as Adrenomedullin 2, ADM2) is an endogenous peptide that belongs to the calcitonin gene-related peptide family and has been reported to play important roles in several types of cancers, including breast cancer. In this study, we sought to investigate how IMD affects the behavior of breast cancer cells, the underlying mechanism of these effects, and whether blockade of IMD has a therapeutic effect against breast cancer.

METHODS

Transcriptome sequencing (RNA-Seq), cell biological experiments, Western blotting, immunoprecipitation, and animal tumor models were used.

RESULTS

IMD expression was significantly increased in breast cancer samples, and the IMD level was positively correlated with lymph node metastasis and Ki67 expression. Cell biological experiments showed that IMD promoted the anchorage-independent growth, migration, and invasive ability of breast cancer cells. Inhibiting IMD activity with an anti-IMD monoclonal antibody blocked these tumor-promoting effects. In addition, blockade of IMD reduced in situ tumor growth and significantly decreased lung metastasis of 4T1 breast cancer in vivo. IMD induced Src kinase phosphorylation, which triggered the transcription of c-Myc, a major oncoprotein controlling the expression of genes that encode ribosomal components. Our data suggest that IMD is involved in breast cancer cell invasion and metastasis, potentially through increasing ribosome biogenesis and protein translation via the Src/c-Myc signaling pathway.

CONCLUSION

These results suggest that IMD may be a novel target for the treatment of breast cancer.

Intermedin facilitates hepatocellular carcinoma cell survival and invasion via ERK1/2-EGR1/DDIT3 signaling cascade

As one of the most malignant cancer types, hepatocellular carcinoma (HCC) is highly invasive and capable of metastasizing to distant organs. Intermedin (IMD), an endogenous peptide belonging to the calcitonin family, has been suggested playing important roles in cancer cell survival and invasion, including in HCC. However, how IMD affects the behavior of HCC cells and the underlying mechanisms have not been fully elucidated. Here, we show that IMD maintains an important homeostatic state by activating the ERK1/2-EGR1 (early growth response 1) signaling cascade, through which HCC cells acquire a highly invasive ability via significantly enhanced filopodia formation. The inhibition of IMD blocks the phosphorylation of ERK1/2, resulting in EGR1 downregulation and endoplasmic reticulum stress (ER) stress, which is evidenced by the upregulation of ER stress marker DDIT3 (DNA damage-inducible transcript 3). The high level of DDIT3 induces HCC cells into an ER-stress related apoptotic pathway. Along with our previous finding that IMD plays critical roles in the vascular remodeling process that improves tumor blood perfusion, IMD may facilitate the acquisition of increased invasive abilities and a survival benefit by HCC cells, and it is easier for HCC cells to obtain blood supply via the vascular remodeling activities of IMD. According to these results, blockade of IMD activity may have therapeutic potential in the treatment of HCC.

Inhibition of Intermedin (Adrenomedullin 2) Suppresses the Growth of Glioblastoma and Increases the Antitumor Activity of Temozolomide

Glioblastoma multiforme (GBM; grade IV glioma) is the most malignant type of primary brain tumor and is characterized by rapid proliferation and invasive growth. Intermedin (IMD) is an endogenous peptide belonging to the calcitonin gene-related peptide family and has been reported to play an important role in cell survival and invasiveness in several types of cancers. In this study, we found that the expression level of IMD was positively related to the malignancy grade of gliomas. The highest expression of IMD was found in GBM, indicating that IMD may play an important role in glioma malignancy. IMD increased the invasive ability of glioma cells by promoting filopodia formation, which is dependent on ERK1/2 activation. IMD-induced ERK1/2 phosphorylation also promoted GBM cell proliferation. In addition, IMD enhanced mitochondrial function and hypoxia-induced responses in GBM cells. Treatment with anti-IMD monoclonal antibodies not only inhibited tumor growth in both ectopic and orthotopic models of GBM but also significantly enhanced the antitumor activity of temozolomide. Our study may provide novel insights into the mechanism of GBM cell invasion and proliferation and provide an effective strategy to improve the therapeutic effect of GBM treatments.

Intermedin promotes hepatic carcinoma cell proliferation through upregulation of miR-155

OBJECTIVE

MicroRNAs (miRNAs) plays an important role in the development of malignant carcinoma. The small peptide intermedin (IMD) can promote hepatic carcinoma cell proliferation. The aim of the present study is to examine the effect of miR-155 on IMD-stimulated hepatic carcinoma cell proliferation.

METHODS

Proliferation of hepatic carcinoma SMMC7721 cells was detected by CCK-8, expression of proliferating cell nuclear antigen (PCNA) and miR-155 was detected by real-time PCR.

RESULTS

We found that IMD promotes the proliferation of SMMC7721 cells in a time and dose-dependent manner. IMD can upregulate the expression of miR-155, and blocking of miR-155 can inhibit the IMD-induced SMMC7721 cell proliferation to some extent.

CONCLUSION

This study demonstrated that IMD can promote the proliferation of human hepatic carcinoma cell line SMMC7721 cells through upregulation of miR-155. This study may contribute to hepatic cancer prevention and therapy.

Intermedin promotes hepatocellular carcinoma cell proliferation through the classical Wnt signaling pathway

The proliferative activity of hepatic carcinoma cells is directly associated with tumorigenesis, tumor development, metastasis and invasion. A variety of cytokines and peptides serve important roles in the development of hepatic carcinoma. The aim of the present study was to examine the effect of intermedin (IMD) on hepatic carcinoma cell proliferation and its mechanism of action. HepG2 hepatic carcinoma cell lines were treated with human recombinant IMD1-53 and its receptor antagonist IMD17-47. Cell proliferation was detected using a Cell Counting kit-8. The activation of the classical Wnt signaling pathway was demonstrated by the ratio of TOPflash:FOPflash luciferase activity. The expression of c-Myc and cyclin D1 downstream of the Wnt signaling pathway were detected using reverse transcription-quantitative polymerase chain reaction analysis. It was demonstrated that IMD may promote the proliferation of HepG2 cells in a time-dependent manner, and that the IMD receptor antagonist IMD17-47 could eliminate this promotion. IMD may activate classical Wnt signaling pathway transcriptional activity and the mRNA levels of certain downstream target genes. Furthermore, blocking of the Wnt signaling pathway may inhibit IMD-induced HepG2 cell proliferation to a certain extent. IMD may promote hepatic carcinoma cell proliferation by binding with receptor antagonist IMD17-47 and activating the Wnt signaling cascade, thus providing a novel avenue for the treatment of hepatic carcinoma.

Intermedin Enlarges the Vascular Lumen by Inducing the Quiescent Endothelial Cell Proliferation

OBJECTIVE

Intermedin plays an important role in vascular remodeling and significantly improves blood perfusion, but the precise mechanism remains unclear. Herein, we aimed to define whether vascular lumen enlargement is responsible for the intermedin-increased blood perfusion and explore the underlying cellular and molecular mechanisms.

APPROACH AND RESULTS

To study the role of intermedin, we generated the IMD-KO (Adm2^-/-) mice using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat-associated 9) system. Intermedin significantly promoted vascular lumen enlargement in vitro (fibrin beads assay) and in vivo (murine retinas), which contributed to the improved blood perfusion in both physiological (retinal) and pathological (tumor) angiogenic models. We designed experiments to calculate the endothelial cell (EC) size and found that the lumen enlargement is because of EC proliferation but not because of a change in cell shape. ECs that construct vessel walls are considered quiescent cells because they are in a state of contact inhibition and show reduced responsiveness to VEGF (vascular endothelial growth factor). Using immunoprecipitation, Western blot assay, and fluorescent microscopy, we found that intermedin induced the formation of a signaling complex containing CRLR (calcitonin receptor-like receptor)/β-arr1 (β-arrestin1)/Src in ECs and promoted it internalizing into cytoplasm in a clathrin-dependent manner to activate downstream ERK1/2 (extracellular signal-regulated kinase 1/2). Importantly, this effect was not abrogated by cell-cell contacts of ECs. Through this mechanism, intermedin could reactivate the quiescent ECs to proliferate, resulting in continuous lumen expanding and a more effective blood perfusion.

CONCLUSIONS

Our findings suggest a novel mechanism that may explain how quiescent ECs overcome the contact inhibition and regain the ability to proliferate for continuous vascular lumen enlargement.

Renalase Expression by Melanoma and Tumor-Associated Macrophages Promotes Tumor Growth through a STAT3-Mediated Mechanism

To sustain their proliferation, cancer cells overcome negative-acting signals that restrain their growth and promote senescence and cell death. Renalase (RNLS) is a secreted flavoprotein that functions as a survival factor after ischemic and toxic injury, signaling through the plasma calcium channel PMCA4b to activate the PI3K/AKT and MAPK pathways. We show that RNLS expression is increased markedly in primary melanomas and CD163(+) tumor-associated macrophages (TAM). In clinical specimens, RNLS expression in the tumor correlated inversely with disease-specific survival, suggesting a pathogenic role for RNLS. Attenuation of RNLS by RNAi, blocking antibodies, or an RNLS-derived inhibitory peptide decreased melanoma cell survival, and anti-RNLS therapy blocked tumor growth in vivo in murine xenograft assays. Mechanistic investigations showed that increased apoptosis in tumor cells was temporally related to p38 MAPK-mediated Bax activation and that increased cell growth arrest was associated with elevated expression of the cell-cycle inhibitor p21. Overall, our results established a role for the secreted flavoprotein RNLS in promoting melanoma cell growth and CD163(+) TAM in the tumor microenvironment, with potential therapeutic implications for the management of melanoma. Cancer Res; 76(13); 3884-94. ©2016 AACR.

Prognostic Value of Plasma Intermedin Level in Patients With Non-ST-Segment Elevation Acute Coronary Syndrome

Intermedin (IMD), an autocrine/paracrine biologically active peptide, plays a critical role in maintaining vascular homeostasis. Recent research has shown that high plasma levels of IMD are associated with poor outcomes for patients with ST-segment elevation acute myocardial infarction. However, the prognostic utility of IMD levels in non-ST-segment elevation acute coronary syndrome (NSTE-ACS) has not yet been investigated. We hypothesized that the level of plasma IMD would have prognostic value in patients with NSTE-ACS. Plasma IMD was determined by radioimmunoassay in 132 NSTE-ACS patients on admission to hospital and 132 sex- and age-matched healthy-control subjects. Major adverse cardiovascular events (MACEs), including death, heart failure, hospitalization, and acute myocardial infarction, were noted during follow-up. In total, 23 patients suffered MACEs during the follow-up period (mean 227 ± 118 days, range 2-421 days). Median IMD levels were higher in NSTE-ACS patients than control [320.0 (250.9/384.6) vs. 227.2 (179.7/286.9) pg/mL, P <0.001]. The area under the receiver-operating characteristic curve for IMD and N-terminal pro-B-type brain natriuretic peptide (NT-proBNP) did not significantly differ (0.73 and 0.79, both P <0.001, respectively; P = 0.946). ROC curve analysis revealed a cut-off value for IMD at 340.7 pg/mL. Cox regression analysis with cardiovascular risk variables and NT-proBNP showed that the risk of MACEs increased by a factor of 12.96 (95% CI, 3.26-49.42; P <0.001) with high IMD levels (at the cut-off value). IMD has potential as a prognostic biomarker for predicting MACEs in patients with NSTE-ACS.

Inhibition of renalase expression and signaling has antitumor activity in pancreatic cancer

An essential feature of cancer is dysregulation of cell senescence and death. Renalase, a recently discovered secreted flavoprotein, provides cytoprotection against ischemic and toxic cellular injury by signaling through the PI3K-AKT and MAPK pathways. Here we show that renalase expression is increased in pancreatic cancer tissue and that it functions as a growth factor. In a cohort of patients with pancreatic ductal adenocarcinoma, overall survival was inversely correlated with renalase expression in the tumor mass, suggesting a pathogenic role for renalase. Inhibition of renalase signaling using siRNA or inhibitory anti-renalase antibodies decreased the viability of cultured pancreatic ductal adenocarcinoma cells. In two xenograft mouse models, either the renalase monoclonal antibody m28-RNLS or shRNA knockdown of renalase inhibited pancreatic ductal adenocarcinoma growth. Inhibition of renalase caused tumor cell apoptosis and cell cycle arrest. These results reveal a previously unrecognized role for the renalase in cancer: its expression may serve as a prognostic maker and its inhibition may provide an attractive therapeutic target in pancreatic cancer.

The novel tumor angiogenic factor, adrenomedullin-2, predicts survival in pancreatic adenocarcinoma

BACKGROUND

Tumor angiogenesis has been demonstrated to have an important role in the development, progression, and metastasis of pancreas cancer. Adrenomedullin-2 (ADM2) is a calcitonin gene-related peptide that has recently been shown to be a novel tumor angiogenesis factor, acting via mitogen-activated protein kinase/extracellular signal-regulated kinase, phosphoinositide 3-kinase/Akt, and vascular endothelial growth factor/vascular endothelial growth factor-2 signaling pathways. Through the use of tissue microarray (TMA) technology, we hypothesize that ADM2 is an important tumor angiogenesis factor in pancreatic cancer.

METHODS

Multiple TMAs were created using tissue from pancreatic cancer patients resected between January 1996 and December 2006. Core tissue samples of formalin-fixed, paraffin-embedded blocks of pancreatic cancer tissue were collected through an institutional review board-approved protocol and linked to available clinicopathologic data. Two TMAs consisting of 112 and 60 patients with pancreatic adenocarcinoma were studied for ADM2 protein expression using a quantitative, automated immunofluorescent microscopy system, a technology that removes potential observer bias in TMA analysis. The results were analyzed using independent Student t-test, chi-square, log-rank regression, and Kaplan-Meier methods.

RESULTS

One hundred sixteen patients were identified for complete analysis, and 56 patients had complete survival data. Median follow-up for survivors was 14.5 mo. Total cellular levels of ADM2 were found to be a predictor of survival in pancreatic cancer. Low ADM2 levels were associated with a higher 5-y survival compared with high ADM2 levels (18% versus 6%, P = 0.05). Median survival was also worse in high ADM2 expressers (18.7 versus 8.6 mo). In accordance with prior-published pancreatic cancer data, a worse histologic grade (P = 0.001), tumor (T) stage (P = 0.009), and overall disease stage (P = 0.004), all portended a worse survival.

CONCLUSIONS

For the first time, we have demonstrated that high levels of ADM2 expression predict a poorer survival in patients with pancreatic adenocarcinoma. This suggests a possible role of ADM2 in pancreas cancer and as a novel biomarker that predicts poorer survival. Additional study of ADM2 in pancreatic cancer will help reveal its true angiogenic role in pancreas cancer and its potential role as a novel therapeutic target.

The prognostic value of intermedin in patients with breast cancer

This study aimed to evaluate the prognostic value of preoperative plasma intermedin levels in breast cancer patients. Plasma intermedin levels of 252 breast cancer women and 100 healthy women were determined using radioimmunoassay kit. Adverse event was defined as first local recurrence, distant metastasis, second primary cancer of another organ, or death from any cause during 5-year follow-up. Disease-free survival was defined as the time between surgery and the date of any adverse event whichever appeared first. Overall survival was defined from surgery to death for any cause. The relationships between plasma intermedin levels and clinical outcomes of breast cancer patients were evaluated using multivariate analysis. The results showed that preoperative plasma intermedin levels were substantially higher in patients than in healthy subjects using t-test. Intermedin was identified as an independent predictor for 5-year mortality, adverse event, disease-free survival, and overall survival using multivariate analysis. Based on receiver operating characteristic curve analysis, preoperative plasma intermedin levels had high predictive value for 5-year mortality and adverse event. In conclusion, preoperative plasma intermedin levels are highly associated with poor patient outcomes and intermedin may be a potential prognostic biomarker for patients with breast cancer.