Netrin-4 as a biomarker promotes cell proliferation and invasion in gastric cancer

IGF2BP2 inhibits invasion and migration of clear cell renal cell carcinoma via targeting Netrin-4 in an m6A-dependent manner

Clear cell renal cell carcinoma (ccRCC), the most common subtype of renal cell carcinoma, often leads to a poor prognosis due to metastasis. The investigation of N6-methyladenosine (m6A) methylation, a crucial RNA modification, and its role in ccRCC, particularly through the m6A reader insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2), revealed significant insights. We found that IGF2BP2 was notably downregulated in ccRCC, which correlated with tumor aggressiveness and poor prognosis. Thus, IGFBP2 has emerged as an independent prognostic factor of ccRCC. Moreover, a strong positive correlation was observed between the expression of IGF2BP2 and Netrin-4. Netrin-4 was also downregulated in ccRCC, and its lower levels were associated with increased malignancy and poor prognosis. Overexpression of IGF2BP2 and Netrin-4 suppressed the invasion and migration of ccRCC cells, while Netrin-4 knockdown reversed these effects in ccRCC cell lines. RNA immunoprecipitation (RIP)-quantitative polymerase chain reaction validated the robust enrichment of Netrin-4 mRNA in anti-IGF2BP2 antibody immunoprecipitates. MeRlP showed significantly increased Netrin4 m6A levels after lGF2BP2 overexpression. Moreover, we found that IGF2BP2 recognized and bound to the m6A site within the coding sequence of Netrin-4, enhancing its mRNA stability. Collectively, these results showed that IGF2BP2 plays a suppressive role in the invasion and migration of ccRCC cells by targeting Netrin-4 in an m6A-dependent manner. These findings underscore the potential of IGF2BP2/Netrin-4 as a promising prognostic biomarker and therapeutic target in patients with ccRCC metastasis.

The nerve cells in gastrointestinal cancers: from molecular mechanisms to clinical intervention

Gastrointestinal (GI) cancer is a formidable malignancy with significant morbidity and mortality rates. Recent studies have shed light on the complex interplay between the nervous system and the GI system, influencing various aspects of GI tumorigenesis, such as the malignance of cancer cells, the conformation of tumor microenvironment (TME), and the resistance to chemotherapies. The discussion in this review first focused on exploring the intricate details of the biological function of the nervous system in the development of the GI tract and the progression of tumors within it. Meanwhile, the cancer cell-originated feedback regulation on the nervous system is revealed to play a crucial role in the growth and development of nerve cells within tumor tissues. This interaction is vital for understanding the complex relationship between the nervous system and GI oncogenesis. Additionally, the study identified various components within the TME that possess a significant influence on the occurrence and progression of GI cancer, including microbiota, immune cells, and fibroblasts. Moreover, we highlighted the transformation relationship between non-neuronal cells and neuronal cells during GI cancer progression, inspiring the development of strategies for nervous system-guided anti-tumor drugs. By further elucidating the deep mechanism of various neuroregulatory signals and neuronal intervention, we underlined the potential of these targeted drugs translating into effective therapies for GI cancer treatment. In summary, this review provides an overview of the mechanisms of neuromodulation and explores potential therapeutic opportunities, providing insights into the understanding and management of GI cancers.

EXOSC5 maintains cancer stem cell activity in endometrial cancer by regulating the NTN4/integrin β1 signalling axis

Endometrial carcinoma (EC) is a common type of uterine cancer in developed countries, originating from the uterine epithelium. The incidence rate of EC in Taiwan has doubled from 2005. Cancer stem cells (CSCs) are a subpopulation of cancer cells that have high tumorigenicity and play a crucial role in the malignant processes of cancer. Targeting molecules associated with CSCs is essential for effective cancer treatments. This study delves into the role of Exosome component 5 (EXOSC5) in EC. Data from The Cancer Genome Atlas suggests a correlation between high EXOSC5 mRNA expression and unfavorable EC prognosis. EXOSC5 knockdown diminished EC-CSC self-renewal and reduced expression of key cancer stemness proteins, including c-MYC and SOX2. Intriguingly, this knockdown significantly curtailed tumorigenicity and CSC frequency in EC tumor spheres. A mechanistic examination revealed a reduction in netrin4 (NTN4) levels in EXOSC5-depleted EC cells. Moreover, NTN4 treatment amplified EC cell CSC activity and, when secreted, NTN4 partnered with integrin β1, subsequently triggering the FAK/SRC axis to elevate c-MYC activity. A clear positive relation between EXOSC5 and NTN4 was evident in 93 EC tissues. In conclusion, EXOSC5 augments NTN4 expression, activating c-MYC via the integrin β1/FAK/SRC pathway, offering potential avenues for EC diagnosis and treatment.

Hepatic Expression of NTN4 and Its Receptors in Patients with Hepatocellular Carcinoma

BACKGROUND

Angiogenesis contributes to hepatocellular carcinoma (HCC) progression by promoting tumor growth and metastasis. Netrin-4 (NTN4) is a secreted glycoprotein that has been reported to control angiogenesis and preserve endothelial homeostasis. Macrovascular invasion of the portal vein, referred to as portal vein invasion (PVI) is associated with poor prognosis in HCC patients. In this work, we sought to understand more about the systemic and hepatic level expression of NTN4 and its receptors in HCC patients with and without portal vein invasion.

METHODS

A total of 154 patients with HCC, and 90 healthy volunteers were recruited in this case-control study. Patients with HCC were further subdivided into those with portal vein invasion (PVI) (n=68), and those without portal vein invasion (NPVI) (n=86). Clinical characteristics and liver function parameters were recorded among the study subjects PVI and NPVI. The serum levels of NTN4 (pg/ml) were estimated by ELISA. HCC tissues and normal non-tumorous liver tissues (controls) were collected for gene expression analysis of NTN4 and its receptors.

RESULTS

ALT, ALP, and GGT levels were significantly elevated in the serum of HCC patients with PVI compared to NPVI and control subjects. Systemic NTN4 was significantly reduced in both PVI and NPVI patients compared to control subjects. At the tissue level, the hepatic NTN4 followed a similar trend with significantly lower mRNA expression in both patients with PVI and NPVI compared to control subjects.

CONCLUSIONS

Systemic and hepatic NTN4 levels were reduced in both PVI and NPVI subjects. The hepatic expression of NTN4 receptors Neogenin and UNC5B were markedly elevated in patients with HCC with PVI compared to NPVI. Future experimental studies might shed the role of NTN4 and its receptors in the development of PVI in HCC.

RNA‑binding protein quaking 5 inhibits the progression of non‑small cell lung cancer by upregulating netrin‑4 expression

It was recently reported that netrin‑4 (Ntn‑4), a component of the extracellular matrix, when downregulated, is involved in the progression of several types of cancer, including breast cancer, colorectal tumours, neuroblastoma and gastric cancer. In the present study, the level of Ntn‑4 was examined in a public non‑small cell lung cancer (NSCLC) dataset from the Netherlands Cancer Institute. This analysis revealed that the mRNA expression level of Ntn‑4 was lower in the samples of patients with NSCLC compared with that in the control samples. Consistent with the mRNA level, the protein level of Ntn‑4 was also found to be decreased in NSCLC cells. However, both the function of Ntn‑4 and the underlying mechanisms of Ntn‑4 downregulation in NSCLC have yet to be fully elucidated. As was anticipated, the overexpression of Ntn‑4 led to a marked decrease in the proliferation, migration and invasion of NSCLC cells. Notably, RNA‑binding protein quaking 5 (Qki‑5) was found to exhibit antitumor activity in lung cancer, not only by enhancing the level of Ntn‑4 by binding to Ntn‑4 mRNA, but also by suppressing the proliferation, invasion and migration of NSCLC cells. However, Qki‑5 is known to be frequently downregulated in NSCLC. Moreover, the knockdown of Ntn‑4 was found to reverse the suppressive effects of Qki‑5 on NSCLC progression both in vitro and in vivo. Taken together, the findings of the present study demonstrate that Ntn‑4 is able to suppress the progression of NSCLC, and that the level of Ntn‑4 can be regulated by Qki‑5. Therefore, Ntn‑4 may be a novel diagnostic and therapeutic target for the treatment of NSCLC.

Serum Levels of Netrin-4 and Its Association With Hepatocellular Carcinoma: Results From a Case-Control Study

BACKGROUND

Angiogenesis plays a vital role in the progression of hepatocellular carcinoma (HCC) by contributing to tumor growth and metastasis. Netrin-4 (NTN4) is a secreted glycoprotein that regulates angiogenesis and maintains endothelial homeostasis. There were no studies found focusing on the value of NTN4 as a serum biomarker for the diagnosis and prognosis of HCC. In this study, we aimed to investigate the systemic expression of NTN4 in patients with HCC. We also explore the association of NTN4 with major clinicopathological and biochemical characteristics of HCC.

METHODS

A total of 116 patients with HCC and 44 healthy volunteers were recruited in this case-control study. Clinical characteristics and liver function parameters were recorded among the study subjects. The levels of α-fetoprotein (AFP) were quantified in patients with HCC. The serum levels of NTN4 (pg/ml) were estimated by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The median NTN4 levels were significantly decreased in patients with HCC when compared to control subjects (p < 0.0001). There was no difference between NTN4 levels in AFP-positive patients and AFP-negative patients (p = 0.39). Of note, NTN4 levels were significantly decreased in HCC patients with metastasis (p < 0.02) and portal vein invasion (p < 0.04). Further, NTN4 levels were significantly reduced in HCC patients with Child-Pugh C score (p < 0.05). The receiver operating characteristic curve for serum levels of NTN4 in the HCC group and control group was generated. At a cut-off of 30 pg/ml, the sensitivity and specificity for NTN4 were 80% and 82%, respectively, with an AUC of 0.894.

CONCLUSIONS

Low levels of NTN4 were associated with increased tumor aggressiveness and metastasis in HCC. Estimation of circulating NTN4 has prognostic value as a minimally invasive biomarker in HCC. Future studies might shed the role of NTN4 in the development of HCC.

Netrin-4 synthesized in satellite cell-derived myoblasts stimulates autonomous fusion

Satellite cells are indispensable for skeletal muscle regeneration and hypertrophy by forming nascent myofibers (myotubes). They synthesize multi-potent modulator netrins (secreted subtypes: netrin-1, -3, and -4), originally found as classical neural axon guidance molecules. While netrin-1 and -3 have key roles in myogenic differentiation, the physiological significance of netrin-4 is still unclear. This study examined whether netrin-4 regulates myofiber type commitment and myotube formation. Initially, the expression profiles indicated that satellite cells isolated from the extensor digitorum longus muscle (EDL muscle: fast-twitch myofiber-abundant) expressed slightly more netrin-4 than the soleus muscle (slow-type abundant) cells. As netrin-4 knockdown inhibited both slow- and fast-type myotube formation, netrin-4 may not directly regulate myofiber type commitment. However, netrin-4 knockdown in satellite cell-derived myoblasts reduced the myotube fusion index, while exogenous netrin-4 promoted myotube formation, even though netrin-4 expression level was maximum during the initiation stage of myogenic differentiation. Furthermore, netrin-4 knockdown also inhibited MyoD (a master transcriptional factor of myogenesis) and Myomixer (a myoblast fusogenic molecule) expression. These data suggest that satellite cells synthesize netrin-4 during myogenic differentiation initiation to promote their own fusion, stimulating the MyoD-Myomixer signaling axis.

Establishment of a prognostic model related to tregs and natural killer cells infiltration in bladder cancer

BACKGROUND

Regulatory T cells (Tregs) and natural killer (NK) cells play an essential role in the development of bladder urothelial carcinoma (BUC).

AIM

To construct a prognosis-related model to judge the prognosis of patients with bladder cancer, meanwhile, predict the sensitivity of patients to chemotherapy and immunotherapy.

METHODS

Bladder cancer information data was obtained from The Cancer Genome Atlas and GSE32894. The CIBERSORT was used to calculate the immune score of each sample. Weighted gene co-expression network analysis was used to find genes that will have the same or similar expression patterns. Subsequently, multivariate cox regression and lasso regression was used to further screen prognosis-related genes. The prrophetic package was used to predict phenotype from gene expression data, drug sensitivity of external cell line and predict clinical data.

RESULTS

The stage and risk scores are independent prognostic factors in patients with BUC. Mutations in FGFR3 lead to an increase in Tregs percolation and affect the prognosis of the tumor, and additionally, EMP1, TCHH and CNTNAP3B in the model are mainly positively correlated with the expression of immune checkpoints, while CMTM8, SORT1 and IQSEC1 are negatively correlated with immune checkpoints and the high-risk group had higher sensitivity to chemotherapy drugs.

CONCLUSION

Prognosis-related models of bladder tumor patients, based on Treg and NK cell percolation in tumor tissue. In addition to judging the prognosis of patients with bladder cancer, it can also predict the sensitivity of patients to chemotherapy and immunotherapy. At the same time, patients were divided into high and low risk groups based on this model, and differences in genetic mutations were found between the high and low risk groups.

gga-miR-20b-5p inhibits infectious bursal disease virus replication via targeting Netrin 4

MicroRNAs (miRNAs) involved host-virus interaction, affecting the replication or pathogenesis of several viruses. Frontier evidences suggested that miRNAs play essential roles in infectious bursal disease virus (IBDV) replication. However, the biological function of miRNAs and the underlying molecular mechanisms are still unclear. Here, we reported that gga-miR-20b-5p acted as a negative factor affecting IBDV infection. We found that gga-miR-20b-5p was significantly up-regulated during IBDV infection in host cells, and that gga-miR-20b-5p effectively inhibited IBDV replication via targeting the expression of host protein netrin 4 (NTN4). In contrast, inhibition of endogenous miR-20b-5p markedly facilitated viral replication associated with enhancing NTN4 expression. Collectively, these findings highlight a crucial role of gga-miR-20b-5p in IBDV replication.

Perineural invasion-associated biomarkers for tumor development

Perineural invasion (PNI) is the process of neoplastic invasion of peripheral nerves and is considered to be the fifth mode of cancer metastasis. PNI has been detected in head and neck tumors and pancreatic, prostate, bile duct, gastric, and colorectal cancers. It leads to poor prognostic outcomes and high local recurrence rates. Despite the increasing number of studies on PNI, targeted therapeutic modalities have not been proposed. The identification of PNI-related biomarkers would facilitate the non-invasive and early diagnosis of cancers, the establishment of prognostic panels, and the development of targeted therapeutic approaches. In this review, we compile information on the molecular mediators involved in PNI-associated cancers. The expression and prognostic significance of molecular mediators and their receptors in PNI-associated cancers are analyzed, and the possible mechanisms of action of these mediators in PNI are explored, as well as the association of cells in the microenvironment where PNI occurs.

The risk variant rs11836367 contributes to breast cancer onset and metastasis by attenuating Wnt signaling via regulating NTN4 expression

Most genome-wide association study (GWAS)-identified breast cancer-associated causal variants remain uncharacterized. To provide a framework of understanding GWAS-identified variants to function, we performed a comprehensive study of noncoding regulatory variants at the NTN4 locus (12q22) and NTN4 gene in breast cancer etiology. We find that rs11836367 is the more likely causal variant, disrupting enhancer activity in both enhancer reporter assays and endogenous genome editing experiments. The protective T allele of rs11837367 increases the binding of GATA3 to the distal enhancer and up-regulates NTN4 expression. In addition, we demonstrate that loss of NTN4 gene in mice leads to tumor earlier onset, progression, and metastasis. We discover that NTN4, as a tumor suppressor, can attenuate the Wnt signaling pathway by directly binding to Wnt ligands. Our findings bridge the gaps among breast cancer-associated single-nucleotide polymorphisms, transcriptional regulation of NTN4, and breast cancer biology, which provides previously unidentified insights into breast cancer prediction and prevention.

Basement membrane stiffness determines metastases formation

The basement membrane (BM) is a special type of extracellular matrix and presents the major barrier cancer cells have to overcome multiple times to form metastases. Here we show that BM stiffness is a major determinant of metastases formation in several tissues and identify netrin-4 (Net4) as a key regulator of BM stiffness. Mechanistically, our biophysical and functional analyses in combination with mathematical simulations show that Net4 softens the mechanical properties of native BMs by opening laminin node complexes, decreasing cancer cell potential to transmigrate this barrier despite creating bigger pores. Our results therefore reveal that BM stiffness is dominant over pore size, and that the mechanical properties of 'normal' BMs determine metastases formation and patient survival independent of cancer-mediated alterations. Thus, identifying individual Net4 protein levels within native BMs in major metastatic organs may have the potential to define patient survival even before tumour formation. The ratio of Net4 to laminin molecules determines BM stiffness, such that the more Net4, the softer the BM, thereby decreasing cancer cell invasion activity.

eQTL Colocalization Analyses Identify NTN4 as a Candidate Breast Cancer Risk Gene

Breast cancer genome-wide association studies (GWASs) have identified 150 genomic risk regions containing more than 13,000 credible causal variants (CCVs). The CCVs are predominantly noncoding and enriched in regulatory elements. However, the genes underlying breast cancer risk associations are largely unknown. Here, we used genetic colocalization analysis to identify loci at which gene expression could potentially explain breast cancer risk phenotypes. Using data from the Breast Cancer Association Consortium (BCAC) and quantitative trait loci (QTL) from the Genotype-Tissue Expression (GTEx) project and The Cancer Genome Project (TCGA), we identify shared genetic relationships and reveal novel associations between cancer phenotypes and effector genes. Seventeen genes, including NTN4, were identified as potential mediators of breast cancer risk. For NTN4, we showed the rs61938093 CCV at this region was located within an enhancer element that physically interacts with the NTN4 promoter, and the risk allele reduced NTN4 promoter activity. Furthermore, knockdown of NTN4 in breast cells increased cell proliferation in vitro and tumor growth in vivo. These data provide evidence linking risk-associated variation to genes that may contribute to breast cancer predisposition.

Germline Mutations in Familial Papillary Thyroid Cancer

Thyroid cancer, predominantly of papillary histology (PTC), is a common cancer mostly diagnosed sporadically. Hereditary PTC is encountered in ~ 5% of cases and may present at an earlier age, with greater risks of metastasis and recurrence, compared with sporadic cases. The molecular basis of hereditary PTC is unknown in most cases. In this study, the genetic basis of hereditary PTC in three Brazilian families was investigated. Whole exome sequencing (WES) was carried out for probands in each family, and validated, pathogenic/likely pathogenic sequence variants (P/LPSVs) were genotyped in additional family members to establish their putative pathogenic role. Overall, seven P/LPSVs in seven novel genes were detected: p.D283N*ANXA3, p.Y157S*NTN4, p.G172W*SERPINA1, p.G188S*FKBP10, p.R937C*PLEKHG5, p.L32Q*P2RX5, and p.Q76*SAPCD1. These results indicate that these novel genes are seemingly associated with hereditary PTC, but extension and validation in other PTC families are required.

Nervous system and gastric cancer

The nervous system has been recently shown to exert impact on gastric cancer directly and indirectly. Gastric cancer cells invade nerve fibers to induce outgrowth and branching of neural cells, and nerve fibers in turn infiltrate into tumor microenvironment to promote progression of gastric cancer. Additionally, the neuro-immune interaction also plays an important role in gastric cancer development. The interplay of nerves and gastric cancer is mediated by many nervous system-associated factors, which can not only be synthesized and released by both cancer cells and nerve terminals, but also participate in regulation of many aspects of gastric cancer such as cell proliferation, angiogenesis, metastasis and recurrence. Furthermore, clinical researches indicate that some of these factors are significant diagnosis and prognosis biomarkers for gastric cancer. Herein, we reviewed recent advances and future prospects of the interaction between nervous system and gastric cancer.

Netrin-1 promotes cell neural invasion in gastric cancer via its receptor neogenin

Neural invasion (NI) is one of the important routes for local spread of gastric cancer (GC) correlated with poor prognosis. However, the exact cellular characteristics and molecular mechanisms of NI in GC are still unclear. Netrin-1(NTN1) as an axon guidance molecule was firstly found during neural system development. Importantly, NTN1 has an essential role in the progression of malignant tumor and specifically mediates the induction of invasion. In this study, we found NTN1 expression was significantly increased in 97 tumor tissues from GC patients and positively correlated with NI (p<0.05). In addition, we detected NTN1 knockdown significantly suppressed GC cells migration and invasion. Moreover, our results showed that reciprocity was observed between GC cells and neurites colonies in dorsal root ganglia (DRG)-GC cells co-culture vitro model. GC cells with NTN1 silencing could suppress their abilities to navigate along surrounding neuritis and this effect was depended on its receptor neogenin. In vivo, NTN1 inhibition also decreased GC cells sciatic nerve invasion. Taken together, our findings argue that NTN1 and its receptor neogenin might act synergistically in promoting GC cells neural invasion. Inhibiting the activity of NTN1 could be a potential strategy targeting NI in GC therapy.

HER2 and p95HER2 differentially regulate miRNA expression in MCF-7 breast cancer cells and downregulate MYB proteins through miR-221/222 and miR-503

The HER2 oncogene and its truncated form p95HER2 play central roles in breast cancer. Here, we show that although HER2 and p95HER2 generally elicit qualitatively similar changes in miRNA profile in MCF-7 breast cancer cells, a subset of changes are distinct and p95HER2 shifts the miRNA profile towards the basal breast cancer subtype. High-throughput miRNA profiling was carried out 15, 36 and 60 h after HER2 or p95HER2 expression and central hits validated by RT-qPCR. miRNAs strongly regulated by p95HER2 yet not by HER2, included miR-221, miR-222, miR-503, miR-29a, miR-149, miR-196 and miR-361. Estrogen receptor-α (ESR1) expression was essentially ablated by p95HER2 expression, in a manner recapitulated by miR-221/-222 mimics. c-Myb family transcription factors MYB and MYBL1, but not MYBL2, were downregulated by p95HER2 and by miR-503 or miR-221/-222 mimics. MYBL1 3′UTR inhibition by miR-221/222 was lost by deletion of a single putative miR-221/222 binding sites. p95HER2 expression, or knockdown of either MYB protein, elicited upregulation of tissue inhibitor of matrix metalloprotease-2 (TIMP2). miR-221/222 and -503 mimics increased, and TIMP2 knockdown decreased, cell migration and invasion. A similar pathway was operational in T47D- and SKBr-3 cells. This work reveals important differences between HER2- and p95HER2- mediated miRNA changes in breast cancer cells, provides novel mechanistic insight into regulation of MYB family transcription factors by p95HER2, and points to a role for a miR-221/222– MYB family–TIMP2 axis in regulation of motility in breast cancer cells.

Netrin Family: Role for Protein Isoforms in Cancer

Netrins form a family of secreted and membrane-associated proteins. Netrins are involved in processes for axonal guidance, morphogenesis, and angiogenesis by regulating cell migration and survival. These processes are of special interest in tumor biology. From the netrin genes various isoforms are translated and regulated by alternative splicing. We review here the diversity of isoforms of the netrin family members and their known and potential roles in cancer.

Novel miRNA expression in the delta opioid signaling pathway mediated cell survivability in an in vitro model of ER stress

Micro RNAs (miRNAs) are small non-coding RNAs which bind to the 3'-untranslated region of a mature mRNA to induce degradation; thereby regulating gene expression. It is reported that dysregulated miRNAs involved in neurodegenerative diseases including Parkinson's disease, could play a significant role as prognostic markers and therapeutic targets. Neuroprotective effect of delta opioid receptors (DOR) and its known miRNA regulation against endoplasmic reticulum (ER) stress have been reported previously by our lab. Current study focuses on understanding the regulation of novel miRNAs by DOR under ER stress. Novel miRNAs were identified for three different samples; control, tunicamycin (ER stress inducer), and tunicamycin+DADLE (DOR agonist). Differentially regulated miRNAs between the different samples were identified and pathway/target genes analysis was carried out. The results suggest that following DOR activation novel miRNAs like xxx-m0073-3p, xxx-m0225-3p, xxx-m0088-3p, xxx-m0098-5p etc. could regulate cell survival mechanisms in neuronal cells (SH-SY5Y) under ER stress.

EGF/EGFR upregulates and cooperates with Netrin-4 to protect glioblastoma cells from DNA damage-induced senescence

BACKGROUND

Glioblastoma multiforme (GBM) is the most malignant central nervous system tumor. Alkylating agent, temozolomide (TMZ), is currently the first-line chemotherapeutic agent for GBM. However, the sensitivity of GBM cells to TMZ is affected by many factors. And, several clinic trials, including co-administration of TMZ with other drugs, have failed in successful treatment of GBM. We have previously reported that Netrin-4 (NTN4), a laminin-like axon guidance protein, plays a protective role in GBM cell senescence upon TMZ-triggered DNA damage. However, the master regulator of NTN4 needs further elucidation. Epidermal growth factor/Epidermal growth factor receptor (EGF/EGFR) can modulate the expression of various extracellular matrix related molecules, and prevent DNA damage in GBM cells. In this study, we investigated the relationship between EGF/EGFR signaling and NTN4, and explored their effect on therapeutic efficacy in GBM cells upon TMZ treatment.

METHODS

Co-expression analysis were performed by using the RNA sequencing data from NIH 934 cell lines and from single cell RNA sequencing data of GBM tumor. The co-expressing genes were used for GO enrichment and signaling pathway enrichment. mRNA expression of the target genes were quantified by qPCR, and cell senescence were investigated by Senescence-Associated Beta-Galactosidase Staining. Protein phosphorylation were observed and analyzed by immunoblotting. The RNA sequencing data and clinical information of TMZ treated patients were extracted from TCGA-glioblastoma project, and then used for Kaplan-Meier survival analysis.

RESULTS

Analysis of RNA sequencing data revealed a potential co-expression relationship between NTN4 and EGFR. GO enrichment of EGFR-correlated genes indicated that EGFR regulates GBM cells in a manner similar to that in central nervous system development and neural cell differentiation. Pathway analysis suggested that EGFR and its related genes contribute to cell adhesion, extracellular matrix (ECM) organization and caspase related signaling. We also show that EGF stimulates NTN4 expression in GBM cells and cooperates with NTN4 to attenuate GBM cell senescence induced by DNA damage, possibly via AKT and ERK. Clinical analysis showed that co-expression of EGFR and NTN4 significantly predicts poor survival in TMZ-treated GBM patients.

CONCLUSIONS

This study indicates that EGF/EGFR regulates and cooperates with NTN4 in DNA damage resistance in GBM. Therefore, our findings provide a potential therapeutic target for GBM.

The Netrin-4/Laminin γ1/Neogenin-1 complex mediates migration in SK-N-SH neuroblastoma cells

Neuroblastoma (NB) is the most common pediatric extracranial solid tumor. It arises during development of the sympathetic nervous system. Netrin-4 (NTN4), a laminin-related protein, has been proposed as a key factor to target NB metastasis, although there is controversy about its function. Here, we show that NTN4 is broadly expressed in tumor, stroma and blood vessels of NB patient samples. Furthermore, NTN4 was shown to act as a cell adhesion molecule required for the migration induced by Neogenin-1 (NEO1) in SK-N-SH neuroblastoma cells. Therefore, we propose that NTN4, by forming a ternary complex with Laminin γ1 (LMγ1) and NEO1, acts as an essential extracellular matrix component, which induces the migration of SK-N-SH cells.

Targeting CAND1 promotes caspase-8/RIP1-dependent apoptosis in liver cancer cells

Cullin-associated NEDD8-dissociated 1 (CAND1) plays a vital role in regulating the activity of Cullin-RING ubiquitin ligases (CRLs), which are frequently dysregulated in cancer. However, the role of CAND1 in hepatocellular carcinoma (HCC) remains unknown. Here, we found that CAND1 was overexpressed in HCC tissues compared to corresponding adjacent liver tissues (71.7% vs 16.7%); high expression of CAND1 was associated with poor overall survival (40.7 vs 57.3 months, P=0.0013); and CAND1 was an independent risk factor for the prognosis of HCC patients (N=138, P=0.018). Functional studies revealed that CAND1 knockdown efficiently suppressed the proliferation of liver cancer cells by activating caspase-8-dependent mitochondrial apoptosis. We also observed a mutual activation loop between caspase-8 and Receptor Interacting Protein 1 (RIP1), which amplified CAND1 knockdown-induced apoptotic signals in the cells. Furthermore, RIP1 inhibitor Necrostatin-1 eliminated the activation of caspase-8. In conclusion, our study pioneered in reporting high CAND1 expression as a predictor of poor prognosis for HCC patients. CAND1 silencing suppressed HCC cell proliferation by inducing caspase-8/RIP1-dependent apoptosis. These findings supported that CAND1 could be a new therapeutic target for liver cancer.

The Netrin-4/ Neogenin-1 axis promotes neuroblastoma cell survival and migration

Neogenin-1 (NEO1) is a transmembrane receptor involved in axonal guidance, angiogenesis, neuronal cell migration and cell death, during both embryonic development and adult homeostasis. It has been described as a dependence receptor, because it promotes cell death in the absence of its ligands (Netrin and Repulsive Guidance Molecule (RGM) families) and cell survival when they are present. Although NEO1 and its ligands are involved in tumor progression, their precise role in tumor cell survival and migration remain unclear. Public databases contain extensive information regarding the expression of NEO1 and its ligands Netrin-1 (NTN1) and Netrin-4 (NTN4) in primary neuroblastoma (NB) tumors. Analysis of this data revealed that patients with high expression levels of both NEO1 and NTN4 have a poor survival rate. Accordingly, our analyses in NB cell lines with different genetic backgrounds revealed that knocking-down NEO1 reduces cell migration, whereas silencing of endogenous NTN4 induced cell death. Conversely, overexpression of NEO1 resulted in higher cell migration in the presence of NTN4, and increased apoptosis in the absence of ligand. Increased apoptosis was prevented when utilizing physiological concentrations of exogenous Netrin-4. Likewise, cell death induced after NTN4 knock-down was rescued when NEO1 was transiently silenced, thus revealing an important role for NEO1 in NB cell survival. In vivo analysis, using the chicken embryo chorioallantoic membrane (CAM) model, showed that NEO1 and endogenous NTN4 are involved in tumor extravasation and metastasis. Our data collectively demonstrate that endogenous NTN4/NEO1 maintain NB growth via both pro-survival and pro-migratory molecular signaling.

Identifying and targeting determinants of melanoma cellular invasion

Epithelial-to-mesenchymal transition is a critical process that increases the malignant potential of melanoma by facilitating invasion and dissemination of tumor cells. This study identified genes involved in the regulation of cellular invasion and evaluated whether they can be targeted to inhibit melanoma invasion. We identified Peroxidasin (PXDN), Netrin 4 (NTN4) and GLIS Family Zinc Finger 3 (GLIS3) genes consistently elevated in invasive mesenchymal-like melanoma cells. These genes and proteins were highly expressed in metastatic melanoma tumors, and gene silencing led to reduced melanoma invasion in vitro. Furthermore, migration of PXDN, NTN4 or GLIS3 siRNA transfected melanoma cells was inhibited following transplantation into the embryonic chicken neural tube compared to control siRNA transfected melanoma cells. Our study suggests that PXDN, NTN4 and GLIS3 play a functional role in promoting melanoma cellular invasion, and therapeutic approaches directed toward inhibiting the action of these proteins may reduce the incidence or progression of metastasis in melanoma patients.

Netrin-1 promotes gastric cancer cell proliferation and invasion via the receptor neogenin through PI3K/AKT signaling pathway

Netrin-1 is a laminin-related protein found to promote proliferation and invasion in multiple types of cancers. Recent studies have identified the function role of netrin-1 in several cancers; however, the influence of netrin-1 in human gastric cancer(GC) remains largely unknown. In this study, we found netrin-1 was upregulated in human GC tissues, where its expression correlated inversely with cancer stage and lymph node metastasis. We detected netrin-1 and its receptor knockdown significantly suppressed GC cells proliferation and invasion, while overexpression netrin-1 reversed these effects. Xenografted analyses using GC cells displayed significantly inhibition of tumor growth and metastasis by netrin-1 depletion. Furthermore, we identified that netrin-1 as a regulator of PI3K/AKT pathway to modulate GC cells proliferation and invasion abilities via its receptor neogenin. Taken together, our findings argued that netrin-1 and its receptor neogenin might act synergistically in promoting GC cells proliferation and invasion through the PI3K/AKT signaling pathway. It is conceivable that netrin-1 could be new therapeutic target to GC therapy.

Preoperative Metabolic Syndrome Is Predictive of Significant Gastric Cancer Mortality after Gastrectomy: The Fujian Prospective Investigation of Cancer (FIESTA) Study

Metabolic syndrome (MetS) has been shown to be associated with an increased risk of gastric cancer. However, the impact of MetS on gastric cancer mortality remains largely unknown. Here, we prospectively examined the prediction of preoperative MetS for gastric cancer mortality by analyzing a subset of data from the ongoing Fujian prospective investigation of cancer (FIESTA) study. This study was conducted among 3012 patients with gastric cancer who received radical gastrectomy between 2000 and 2010. The latest follow-up was completed in 2015. Blood/tissue specimens, demographic and clinicopathologic characteristics were collected at baseline. During 15-year follow-up, 1331 of 3012 patients died of gastric cancer. The median survival time (MST) of patients with MetS was 31.3months, which was significantly shorter than that of MetS-free patients (157.1months). The coexistence of MetS before surgery was associated with a 2.3-fold increased risk for gastric cancer mortality (P<0.001). The multivariate-adjusted hazard ratios (HRs) were increased with invasion depth T1/T2 (HR=2.78, P<0.001), regional lymph node metastasis N0 (HR=2.65, P<0.001), positive distant metastasis (HR=2.53, P<0.001), TNM stage I/II (HR=3.00, P<0.001), intestinal type (HR=2.96, P<0.001), negative tumor embolus (HR=2.34, P<0.001), and tumor size ≤4.5cm (HR=2.49, P<0.001). Further survival tree analysis confirmed the top splitting role of TNM stage, followed by MetS or hyperglycemia with remarkable discrimination ability. In this large cohort study, preoperative MetS, especially hyperglycemia, was predictive of significant gastric cancer mortality in patients with radical gastrectomy, especially for early stage of gastric cancer.

4E-BP1, a multifactor regulated multifunctional protein

Eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1) is a member of a family of translation repressor proteins, and a well-known substrate of mechanistic target of rapamycin (mTOR) signaling pathway. Phosphorylation of 4E-BP1 causes its release from eIF4E to allow cap-dependent translation to proceed. Recently, 4E-BP1 was shown to be phosphorylated by other kinases besides mTOR, and overexpression of 4E-BP1 was found in different human carcinomas. In this review, we summarize the novel findings on mTOR independent 4E-BP1 phosphorylation in carcinomas. The implications of overexpression and possible multi-function of 4E-BP1 are also discussed.

Depression accelerates the development of gastric cancer through reactive oxygen species‑activated ABL1 (Review)

Depression is a common symptom among gastric cancer (GC) patients and serves as a potential indication of poor prognosis and advanced cancer clinical stage. However, the molecular mechanism of depression‑associated poor prognoses of GC patients remains unclear. Recent studies have revealed that GC patients with depression are under high levels of oxidative stress (OS) status that is accompanied by the dysfunction of numerous proto‑oncogenes, including the ABL proto‑oncogene 1 (ABL1), which is a non‑receptor tyrosine kinase. Recent evidence indicates that ABL1 was dysregulated in both major depressive disorder (MDD) and cancer patients with depression, and high levels of reactive oxygen species (ROS) can lead to the activation of ABL1 in response to OS and that activated ABL1 subsequently contributes to development of GC via interactions with the downstream targets and corresponding signaling pathways. In this review, we examine the evidence to illuminate the molecular mechanism of ABL1 in the progression of GC patients with depression and identify out new and effective methods for the initial and long‑term treatment of GC.