NRP-1 silencing suppresses hepatocellular carcinoma cell growth in vitro and in vivo

VEGF/Nrp1/HIF-1α promotes proliferation of hepatocellular carcinoma through a positive feedback loop

To investigate the role of neuropilin1 (Nrp1) in glucose metabolism and proliferation of hepatocellular carcinoma (HCC) cells and to analyze its mechanism of action. The CRISPR gene knockout technique was used to knock out the Nrp1 gene in two HCC cell lines. The effect of Nrp1 on the proliferation of HCC cells was assessed in the CCK8 assay and plate cloning assay. The expression levels of glucose consumption, lactate production, and essential proteins of the glycolytic pathway were detected to explore the effect of Nrp1 on glucose metabolism in HCC cells. Using CoCl2 to revert the expression of hypoxia inducible factor-1α (HIF-1α), the role of HIF-1α in the pro-HCC cell metabolism of Nrp1 were demonstrated. The protein synthesis inhibitor CHX and proteasome inhibitor MG-132 was used to analyze the molecular mechanism of action of Nrp1 on HIF-1α. The Kaplan-Meier method was used to calculate survival rates and plot survival curves. Based on the CCK8 assay and plate cloning assay, we found that Nrp1 knockout significantly inhibited the proliferation of HCC cells. Nrp1 inhibitor suppressed lactate production and glucose consumption in HCC cells. Knockout of Nrp1 decreased the expression of glycolytic pathway-related proteins and HIF-1α protein. Furthermore, by joint use of CoCl2 and NRP1 knockout, we confirmed that reverting HIF-1α expression could reverse the effect of Nrp1 knockout on HCC cell metabolism in vitro. Mechanistically, Nrp1 showed a close correlation with the stability of HIF-1α protein in protein stability assay. Finally, we revealed that high expression of Nrp1 in HCC tissues was associated with poor overall survival and disease-free survival of the patients. Nrp1 accelerates glycolysis and promotes proliferation of HCC by regulating HIF-1α protein stability and through the VEGF/Nrp1/HIF-1α positive feedback loop.

Neuropilins as potential biomarkers in hepatocellular carcinoma: a systematic review of basic and clinical implications

Hepatocellular carcinoma (HCC) is one of the most common and deadly cancers worldwide and is characterized by complex molecular carcinogenesis. Neuropilins (NRPs) NRP1 and NRP2 are the receptors of multiple proteins involved in key signaling pathways associated with tumor progression. We aimed to systematically review all the available findings on their role in HCC. We searched the Scopus, Web of Science (WOS), PubMed, Cochrane and Embase databases for articles evaluating NRPs in preclinical or clinical HCC models. This study was registered in PROSPERO (CRD42022349774) and include 49 studies. Multiple cellular and molecular processes have been associated with one or both NRPs, indicating that they are potential diagnostic and prognostic biomarkers in HCC patients. Mainly NRP1 has been shown to promote tumor cell survival and progression by modulating several signaling pathways. NRPs mainly regulate angiogenesis, invasion and migration and have shown to induce invasion and metastasis. They also regulate the immune response and tumor microenvironment, showing a crucial interplay with the hypoxia response and microRNAs in HCC. Altogether, NRP1 and NRP2 are potential biomarkers and therapeutic targets, providing novel insight into the clinical landscape of HCC patients.

The Recent Advance of Cell-Penetrating and Tumor-Targeting Peptides as Drug Delivery Systems Based on Tumor Microenvironment

Cancer has become the primary reason for industrial countries death. Although first-line treatments have achieved remarkable results in inhibiting tumors, they could have serious side effects because of insufficient selectivity. Therefore, specific localization of tumor cells is currently the main desire for cancer treatment. In recent years, cell-penetrating peptides (CPPs), as a kind of promising delivery vehicle, have attracted much attention because they mediate the high-efficiency import of large quantities of cargos in vivo and vitro. Unfortunately, the poor targeting of CPPs is still a barrier to their clinical application. In order to solve this problem, researchers use the various characteristics of tumor microenvironment and multiple receptors to improve the specificity toward tumors. This review focuses on the characteristics of the tumor microenvironment, and introduces the development of strategies and peptides based on these characteristics as drug delivery system in the tumor-targeted therapy.

Hepatocellular carcinoma cells loss lenvatinib efficacy in vitro through autophagy and hypoxia response-derived neuropilin-1 degradation

Despite pharmacological advances such as lenvatinib approval, therapeutic failure of hepatocellular carcinoma (HCC) remains a big challenge due to the complexity of its underlying molecular mechanisms. Neuropilin-1 (NRP1) is a co-receptor involved in several cellular processes associated to chemoresistance development. Since both the double-edged process of autophagy and hypoxia-derived response play crucial roles in the loss of therapeutic effectiveness, herein we investigated the interplay among NRP1, autophagy and hypoxia in development of lenvatinib resistance in HCC cell lines. We first analyzed NRP1 expression levels in human HCC samples from public databases, found significantly increased NRP1 expression in human HCC samples as well as its correlation with advanced tumor and metastasis stages. Among 3 HCC cell lines (HepG2, Huh-7 and Hep3B), Hep3B and Huh-7 cells showed significantly increased NRP1 expression levels and cell migration ability together with higher susceptibility to lenvatinib. We demonstrated that NRP1 gene silencing significantly enhanced the anticancer effects of lenvatinib on Hep3B and Huh-7 cells. Furthermore, lenvatinib suppressed NRP1 expression through promoting autophagy in Hep3B and Huh-7 cells; co-treatment with bafilomycin A1 attenuated the antitumor effects of lenvatinib, and NRP1 silencing prevented this loss of in vitro effectiveness of lenvatinib even in the presence of bafilomycin A1. In addition, exposure to a hypoxic microenvironment significantly decreased NRP1 expression through autophagy in Hep3B and Huh-7 cells. Under hypoxia, HIF-1α directly modulated NRP1 expression; HIF-1α silencing not only enhanced the anticancer effects of combined lenvatinib and hypoxia, but also prevented the loss of effectiveness caused by bafilomycin A1, highlighting the potential role of HIF-1α-derived hypoxia response in the adaptive cellular response to lenvatinib and promoting resistance acquisition by autophagy modulation. Overall, NRP1 may constitute a potential therapeutic target to prevent lenvatinib failure derived from a hypoxia-associated modulation of autophagy in advanced HCC.

Neuropilin-1 is required for endothelial cell adhesion to soluble vascular endothelial growth factor receptor 1

Neuropilin‐1 (NRP‐1) is a semaphorin receptor involved in neuron guidance, and a co‐receptor for selected isoforms of the vascular endothelial growth factor (VEGF) family. NRP‐1 binding to several VEGF‐A isoforms promotes growth factor interaction with VEGF receptor (VEGFR)‐2, increasing receptor phosphorylation. Additionally, NRP‐1 directly interacts with VEGFR‐1, but this interaction competes with NRP‐1 binding to VEGF‐A165 and does not enhance VEGFR‐1 activation. In this work, we investigated in detail the role of NRP‐1 interaction with the soluble isoform of VEGFR‐1 (sVEGFR‐1) in angiogenesis. sVEGFR‐1 acts both as a decoy receptor for VEGFs and as an extracellular matrix protein directly binding to α5β1 integrin on endothelial cells. By combining cell adhesion assays and surface plasmon resonance experiments on purified proteins, we found that sVEGFR‐1/NRP‐1 interaction is required both for α5β1 integrin binding to sVEGFR‐1 and for endothelial cell adhesion to a sVEGFR‐1‐containing matrix. We also found that a previously reported anti‐angiogenic peptide (Flt_2‐11), which maps in the second VEGFR‐1 Ig‐like domain, specifically binds NRP‐1 and inhibits NRP‐1/sVEGFR‐1 interaction, a process that likely contributes to its anti‐angiogenic activity. In view of potential translational applications, we developed a five‐residue‐long peptide, derived from Flt_2‐11, which has the same ability as the parent Flt_2‐11 peptide to inhibit cell adhesion to, and migration towards, sVEGFR‐1. Therefore, the Flt_2‐5 peptide represents a potential anti‐angiogenic compound per se, as well as an attractive lead for the development of novel angiogenesis inhibitors acting with a different mechanism with respect to currently used therapeutics, which interfere with VEGF‐A165 binding.

Soluble Neuropilin-1 is an independent marker of poor prognosis in early breast cancer

Background

Neuropilin-1 (NRP-1) is a transmembrane protein that acts as a multifunctional non-tyrosine kinase receptor with an established role in development and immunity. NRP-1 also regulates tumor biology, and high expression levels of tissue NRP-1 have been associated with a poor prognosis. Recently, ELISA-based quantification of soluble NRP-1 (sNRP-1) has become available, but little is known about the prognostic value of sNRP-1 in malignancies.

Materials and methods

We measured sNRP-1 in the serum of 509 patients with primary early breast cancer (BC) at the time of diagnosis using ELISA.

Results

Mean serum values of sNRP-1 were 1.88 ± 0.52 nmol/l (= 130.83 ± 36.24 ng/ml). SNRP-1 levels weakly correlated with age, and were higher in peri- and postmenopausal patients compared to premenopausal patients, respectively (p < 0.0001). Low levels of sNRP-1 were associated with a significant survival benefit compared to high sNRP-1 levels at baseline (p = 0.005; HR 1.94; 95%CI 1.23–3.06). These findings remained significant after adjustment for tumor stage including lymph node involvement, grading, hormone receptor, HER2 status, and age (p = 0.022; HR 1.78; 95%CI 1.09–2.91).

Conclusion

Our findings warrant further investigations into the prognostic and therapeutic potential of sNRP-1 in BC.

Serum concentrations of neuropilin-1 in women with endometriosis

Objective of this work is to investigate, for the first time, serum concentration of neuropilin-1 (NRP-1), aiming to evaluate its diagnostic performance in endometriosis and usability as a potential non-invasive serum marker of endometriosis. Two hundred women were treated laparoscopically. After laparoscopic surgery women were divided into two groups: 120 women diagnosed with endometriosis and 80 healthy women (control group). Blood samples were taken from all women undergoing laparoscopy half an hour before the induction of anesthesia, for the purpose of collection of serum. The level of NRP-1 in serum was assayed by a standardised sandwich enzyme-linked immunosorbent assay. Differences between endometriosis and healthy control group in NRP-1 levels were significant. All values were significantly and several times higher in patients group, p < .001. After receiver operating characteristic analysis, the area under curve was 0.97 (95% confidence interval: 0.941 to 0.989, p < .0001) at 11 µg/L cut-off level for NRP-1. Preliminary threshold values for NRP-1 in serum were assumed to serve as diagnostic parameters with sensitivity of 99.3% and specificity of 97.8%. Serum concentration of NRP-1 can be considered as a potentially good laboratory diagnostic, non-invasive marker for endometriosis.

Expression and clinical significance of neuropilin-1 in Epstein-Barr virus-associated lymphomas

BACKGROUND

The expression of neuropilin-1 (NRP-1) in Epstein-Barr virus (EBV)-associated lymphomas and its relationships with clinicopathological parameters was investigated.

METHODS

The researchers compared 111 cases of patients with lymphoma to 20 cases of reactive lymphoid hyperplasia. In situ hybridization was applied to observe the expression of EBV-encoded RNA (EBER) in lymphomas, and immunohistochemistry was used to detect the NRP-1 expression in lymphoma tissues and lymph node tissues with reactive hyperplasia.

RESULTS

In these 111 cases, the EBER of 62 cases (55.9%) appeared positive. NRP-1 was relatively highly expressed in lymphomas (P= 0.019). Further, NRP-1 showed higher expression in lymphomas with positive EBER than in negative ones. A comprehensive analysis revealed that NRP-1 was differently expressed in NK/T-cell lymphoma, Hodgkin's lymphoma, diffuse large B-cell lymphoma, and anaplastic large cell lymphoma (P= 0.027). Moreover, highly expressed NRP-1 was found to be a useful independent prognostic factor in assessing overall survival and progression-free survival rates in cases of non-Hodgkin's lymphoma (NHL).

CONCLUSIONS

NRP-1 exhibited higher expression in lymphomas, and it was positively expressed in EBV-positive lymphomas. Moreover, highly expressed NRP-1 can be used as an undesirable independent prognostic factor in NHL.

Neuropilin-1 is associated with the prognosis of cervical cancer in Henan Chinese population

Objective: Neuropilin-1 has been reported to be a valuable diagnostic biomarker in patients with cervical intraepithelial neoplasia (CIN) and early cervical cancer. The aim of this study was to investigate the association between Neuropilin-1 and the prognosis of cervical cancer in Henan Chinese population.

Methods: Tissues were collected in The Third Affiliated Hospital of Zhengzhou University between 2010 and 2012, determining the level and expression of Neuropilin-1 in different cervical lesions by immunohistochemistry. The cell proliferation assay, wound-healing assays and Transwell assay were performed to explore the ability of proliferation, migration and invasion for Hela and Caski cells after NRP-1 was knocked down by shRNA transfection. Western blotting was performed to investigate the role of NRP-1 in endothelial-to-mesenchymal transition (EndMT). Tumor xenografts model was used to evaluate the effect of NRP-1 on the tumor growth.

Results: The expression of NRP-1 was upregulated in the tumor tissues compared with the CIN and normal tissues (P<0.0001). The overall survival time of the high NRP-1 expression group was significantly shorter than that of the low NRP-1 expression group (P<0.0001); NRP-1-depleted cells had dramatically lower rate of proliferation, migration and invasion compared to control cells (all P<0.05). Depletion of NRP-1 significantly suppressed the growth of CaSki xenograft tumor in nude mice.

Conclusions: The current study demonstrated that NRP-1 expression is significantly correlated with the progression of CC. Notably, high NRP-1 expression is correlated with a poorer survival in patients with CC, and has been shown to be an independent prognostic factor.

Untargeted Metabolomics Study of the In Vitro Anti-Hepatoma Effect of Saikosaponin d in Combination with NRP-1 Knockdown

Saikosaponin d (SSd) is one of the main active ingredients in Radix Bupleuri. In our study, network pharmacology databases and metabolomics were used in combination to explore the new targets and reveal the in-depth mechanism of SSd. A total of 35 potential targets were chosen through database searching (HIT and TCMID), literature mining, or chemical similarity predicting (Pubchem). Out of these obtained targets, Neuropilin-1 (NRP-1) was selected for further research based on the degree of molecular docking scores and novelty. Cell viability and wound healing assays demonstrated that SSd combined with NRP-1 knockdown could significantly enhance the damage of HepG2. Metabolomics analysis was then performed to explore the underlying mechanism. The overall difference between groups was quantitatively evaluated by the metabolite deregulation score (MDS). Results showed that NRP-1 knockdown exhibited the lowest MDS, which demonstrated that the metabolic profile experienced the slightest interference. However, SSd alone, or NRP-1 knockdown in combination with SSd, were both significantly influenced. Differential metabolites mainly involved short- or long-chain carnitines and phospholipids. Further metabolic pathway analysis revealed that disturbed lipid transportation and phospholipid metabolism probably contributed to the enhanced anti-hepatoma effect by NRP-1 knockdown in combination with SSd. Taken together, in this study, we provided possible interaction mechanisms between SSd and its predicted target NRP-1.

Genetic status of KRAS influences Transforming Growth Factor-beta (TGF-β) signaling: An insight into Neuropilin-1 (NRP1) mediated tumorigenesis

Oncogenic RAS and deregulated transforming growth factor-beta (TGF)-β signaling have been implicated in several cancers. So far, attempts to target either one of them therapeutically have been futile as both of them are involved in multiple fundamental cellular processes and the normal forms are expressed by almost all cells. Hence, their inhibition would disrupt several physiological processes. Besides, their downregulation stimulates the tumor cells to develop adaptive mechanisms and would most likely be ineffective as therapeutic targets. Furthermore, growing literature suggests that both of these signaling pathways converge to enhance tumor development. Therefore, a lot of interest has been generated to explore the areas where these pathways interface that might identify new molecules that could potentially serve as novel therapeutic targets. In this review, we focus on such convergent signaling and cross-interaction that is mediated by neuropilin-1 (NRP1), a receptor that can interact with multiple growth factors including TGF-β for promoting tumorigenesis process.

Systematic analysis of the molecular mechanism of microRNA-124 in hepatoblastoma cells

The present study aimed to identify the molecular mechanisms of microRNA-124 (miRNA-124/miR-124) in hepatoblastoma. The GSE6207 microarray dataset, obtained from the Gene Expression Omnibus database, included samples extracted from HepG2 cells transfected with miR-124 duplex (the experimental group) or negative control (the control group) at 4, 8, 16, 24, 32, 72 and 120 h after transfection. Differentially expressed genes (DEGs) were screened between the two groups. miR-124 activity was inferred based on the expression of its target genes. The mRNAs targeted by miR-124 were predicted and a miR-124-target mRNA network was constructed. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed for the target genes. The number of DEGs was highest at 72 h. The experimental group had higher miR-124 activity than that of the control group at 4, 8, 16, 24 and 120 h. Small GTPase-mediated signal transduction and Ras protein signal transduction were significant GO terms enriched with syndecan binding protein (SDCBP), Ras homolog family member G (RHOG) and Rho-GDP dissociation inhibitor-α (ARHGDIA). Regulation of actin cytoskeleton, D-glutamine and D-glutamate metabolism, and axon guidance were significant pathways. Axon guidance pathway was associated with neuropilin (NRP1), MET proto-oncogene, receptor tyrosine kinase (MET) and semaphorin 7A, GPI membrane anchor (SEMA7A). Small GTPase-mediated signal transduction, Ras protein signal transduction, regulation of actin cytoskeleton pathway, D-glutamine and D-glutamate metabolism pathway, axon guidance pathway, SDCBP, RHOG, ARHGDIA, NRP1, SEMA7A, and MET may be implicated in the underlying mechanisms of miR-124 overexpression in hepatoblastoma.

Genetic status of KRAS modulates the role of Neuropilin-1 in tumorigenesis

Neuropilin-1 (NRP1), a non-tyrosine kinase receptor, is overexpressed in many cancers including pancreatic and lung cancers. Inhibition of NRP1 expression, however, has differing pro-tumor vs. anti-tumor effects, depending on the cancer types. To understand the differential role of NRP1 in tumorigenesis process, we utilized cells from two different cancer types, pancreatic and lung, each containing either wild type KRAS (KRAS ^wt) or mutant KRAS (KRAS ^mt). Inhibition of NRP1 expression by shRNA in both pancreatic and lung cancer cells containing dominant active KRAS ^mt caused increased cell viability and tumor growth. On the contrary, inhibition of NRP1, in the tumor cells containing KRAS ^wt showed decreased tumor growth. Importantly, concurrent inhibition of KRAS ^mt and NRP1 in the tumor cells reverses the increased viability and leads to tumor inhibition. We found that NRP1 shRNA expressing KRAS ^mt tumor cells caused increased cell viability by decreasing SMAD2 phosphorylation. Our findings demonstrate that the effects of NRP1 knockdown in cancer cells are dependent on the genetic status of KRAS.

Neuropilins and liver

Neuropilins (NRPs) are highly conserved transmembrane glycoproteins that possess pleiotropic functions. Neuropilin-1 (NRP1) and its homologue neuropilin-2 interact as coreceptors with both class 3 semaphorins and vascular endothelial growth factor and are involved in neuronal guidance and angiogenesis, respectively. The contribution of NRPs to tumor angiogenesis has been highlighted in previous studies, leading to the development of NRP antagonists as novel anti-angiogenesis therapies. However, more recent studies have demonstrated that NRPs have a much broader spectrum of activity in the integration of different pathways in physiological and pathological conditions. A few studies investigated the role of NRPs in both malignant and non-neoplastic liver diseases. In normal liver, NRP1 is expressed in hepatic stellate cells and liver sinusoidal endothelial cells. NRP1 expression in hepatocytes has been associated with malignant transformation and may play an important role in tumor behavior. A contribution of NRPs in sinusoidal remodeling during liver regeneration has been also noted. Studies in chronic liver diseases have indicated that, besides its influence on angiogenesis, NRP1 might contribute to the progression of liver fibrosis owing to its effects on other growth factors, including transforming growth factor β1. As a result, NRP1 has been identified as a promising therapeutic target for future antifibrotic therapies based on the simultaneous blockade of multiple growth factor signaling pathways. In this review, the structure of NRPs and their interactions with various ligands and associated cell surface receptors are described briefly. The current understanding of the roles of the NRPs in liver diseases including tumors, regeneration and fibrogenesis, are also summarized.

Circulating soluble neuropilin-1 in patients with early cervical cancer and cervical intraepithelial neoplasia can be used as a valuable diagnostic biomarker

Objective. To investigate soluble neuropilin-1 (sNRP-1) in circulating and NRP-1 protein in cervical tissues from patients with cervical cancer or cervical intraepithelial neoplasia (CIN). Methods. sNRP-1 was measured in 64 preoperative patients and 20 controls. NRP-1 protein in cervical tissue was detected in 56 patients and 20 controls. Results. Both sNRP-1 and NRP-1 proteins were correlated with stage. sNRP-1 presented a high diagnostic ability of cervical cancer and CIN, with a sensitivity of 70.97% and a specificity of 73.68%. Conclusions. sNRP-1 in circulating can serve as a possible valuable diagnostic biomarker for cervical cancer and CIN.

Immunohistological insight into the correlation between neuropilin-1 and epithelial-mesenchymal transition markers in epithelial ovarian cancer

The mechanism by which neuropilin-1 (NRP-1) induces malignancy in Epithelial Ovarian Cancer (EOC) is still unknown. This study is the first to demonstrate the relationship between NRP-1 expression and EMT markers vimentin, N-cadherin, E-cadherin and Slug. We used tissue microarrays containing the three main subtypes of EOC tumors: serous, mucinous cystadenocarcinoma and endometrioid adenocarcinoma and representative cases retrieved from our pathology archives. Immunohistochemistry was performed to detect the expression levels and location of NRP-1 and the aforementioned EMT proteins. NRP-1 was mainly expressed on cancer cells but not in normal ovarian surface epithelium (OSE). The Immunoreactive Scoring (IRS) values revealed that the expression of NRP-1, Slug and E-cadherin in the malignant subtypes of ovarian tissues was significantly higher (5.18 ± 0.64, 4.84 ± 0.7, 4.98 ± 0.68, respectively) than their expression in the normal and benign tissues (1.04 ± 0.29, 0.84 ± 0.68, 1.71 ± 0.66, respectively), with no significant differences among the studied subtypes. Vimentin was expressed in the cancer cell component of 43% of tumors and it was exclusively localized in the stroma of all mucinous tumors. The Spearman's rho value indicated that NRP-1 is positively related to the EMT markers E-cadherin and Slug. This notion might indicate that NRP-1 is a partner in the EMT process in EOC tumors.

Prognostic implication of neuropilin-1 upregulation in human nasopharyngeal carcinoma

OBJECTIVE

As a receptor for both vascular endothelial growth factors and semaphorin, neuropilin-1 (NRP-1) is reported to be up-regulated in cells of several cancers. However, its roles in human nasopharyngeal carcinoma (NPC) are still unclear. Therefore, the goal of this study was to investigate the expression pattern of NRP-1 in NPC tissues, to clarify the clinical significance of NRP-1 expression in NPC as well as the potential prognostic implication of NRP-1 expression.

METHODS

Immunohistochemistry was performed to detect the expression of NRP-1 in tumor tissue samples from 266 NPC patients. The association of NRP-1 protein expression with the clinicopathological characteristics and the prognosis of NPC were subsequently assessed.

RESULTS

Immunohistochemical analysis showed that 176 of 266 (66.17%) paraffin-embedded archival NPC biopsies showed high expression of NRP-1, but no non-cancerous nasopharyngeal specimens showed positive expression of NRP-1. In addition, high NRP-1 expression was significantly associated with advanced clinical stage (P = 0.02), positive recurrence (P = 0.001) and metastasis status (P = 0.001) of NPC. Moreover, the NPC patients with higher NRP-1 expression had shorter overall survival, whereas patients with lower NRP-1 expression had better survival (P < 0.001). Furthermore, the multivariate analysis indicated that the overexpression of NRP-1 protein was an independent prognostic factor for overall survival (P = 0.001) in NPC patients.

CONCLUSION

These findings suggest for the first time that NRP-1 upregulation may be a novel biomarker for the prediction of advanced tumor progression and unfavorable prognosis in NPC patients who may benefit from alternative treatment strategy and targeted treatment.

VIRTUAL SLIDES

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1507827881105018.