High expression of NDRG3 associates with unfavorable overall survival in non-small cell lung cancer

Elevated N-Myc downstream-regulated gene 3 expression indicates poor survival in epithelial ovarian cancer

N-Myc downstream-regulated gene 3 (NDRG3), a member of the NDRG family, plays an important role in the development, progression, invasiveness, and metastasis of multiple tumor types. This study focuses on NDRG3 expression in epithelial ovarian cancer (EOC) and the correlation between NDRG3 expression and prognostic indicators. First, the LinkedOmics database was used to analyze the expression of genes associated with NDRG3, and then gene ontology and Kyoto encyclopedia of genes and genomes (KEGG) functional enrichment analyses and methylation analysis of NDRG3-related genes were performed to identify co-expressed genes. A protein-protein interaction network was constructed using the STRING database. Subsequently, quantitative polymerase chain reaction was performed to determine the mRNA expression level of NDRG3 in 22 fresh EOC tissue samples. In addition, immunohistochemistry was performed to detect the expression of NDRG3 protein in 110 EOC microarray samples. Cox regression and Kaplan-Meier survival analyses were performed to assess the prognostic value of NDRG3. Bioinformatics analysis showed that NDRG3 had a broad impact on the transcriptome and that genes that were co-expressed with NDRG3 were primarily involved in organ- or tissue-specific immune response, response to chemokine, interleukin-1 production, and other related pathways. The KEGG pathway analysis suggested that genes co-expressed with NDRG3 were also enriched in signaling pathways, including the interleukin-17 signaling pathway. The mRNA expression levels of NDRG3 were significantly higher in EOC tissues than in paracancerous nontumor tissues (P < .01). NDRG3 expression in EOC was correlated with distant metastasis (P = .02), tumor-node-metastasis stage (P = .03), and patient prognosis (P = .01). Moreover, the disease-free survival and overall survival times of EOC patients decreased with increasing NDRG3 expression. High NDRG3 expression and lymph node metastasis were identified as independent prognostic factors in 110 EOC patients. NDRG3 plays a key role in ovarian cancer progression. High NDRG3 expression is correlated with multiple clinicopathologic features of EOC and may be an indicator of a poor prognosis in EOC.

Anti-proteolytic regulation of KRAS by USP9X/NDRG3 in KRAS-driven cancer development

Cancers with activating mutations of KRAS show a high prevalence but remain intractable, requiring innovative strategies to overcome the poor targetability of KRAS. Here, we report that KRAS expression is post-translationally up-regulated through deubiquitination when the scaffolding function of NDRG3 (N-Myc downstream-regulated gene 3) promotes specific interaction between KRAS and a deubiquitinating enzyme, USP9X. In KRAS-mutant cancer cells KRAS protein expression, downstream signaling, and cell growth are highly dependent on NDRG3. In conditional KrasG12D knock-in mouse models of pancreatic ductal adenocarcinoma, Ndrg3 depletion abolishes Kras protein expression and suppresses intraepithelial neoplasia formation in pancreas. Mechanistically, KRAS protein binds to the C-terminal serine/threonine-rich region of NDRG3, subsequently going through deubiquitination by USP9X recruited to the complex. This interaction can be disrupted in a dominant-negative manner by a C-terminal NDRG3 fragment that binds KRAS but is defective in USP9X binding, highly suppressing KRAS protein expression and KRAS-driven cell growth. In summary, KRAS-driven cancer development critically depends on the deubiquitination of KRAS protein mediated by USP9X/NDRG3, and KRAS-addicted cancers could be effectively targeted by inhibiting the KRAS-NDRG3 interaction.

Glycogen Storage Disease Phenotypes Accompanying the Perturbation of the Methionine Cycle in NDRG3-Deficient Mouse Livers

N-Myc downstream regulated gene 3 (NDRG3) is a unique pro-tumorigenic member among NDRG family genes, mediating growth signals. Here, we investigated the pathophysiological roles of NDRG3 in relation to cell metabolism by disrupting its functions in liver. Mice with liver-specific KO of NDRG3 (Ndrg3 LKO) exhibited glycogen storage disease (GSD) phenotypes including excessive hepatic glycogen accumulation, hypoglycemia, elevated liver triglyceride content, and several signs of liver injury. They suffered from impaired hepatic glucose homeostasis, due to the suppression of fasting-associated glycogenolysis and gluconeogenesis. Consistently, the expression of glycogen phosphorylase (PYGL) and glucose-6-phosphate transporter (G6PT) was significantly down-regulated in an Ndrg3 LKO-dependent manner. Transcriptomic and metabolomic analyses revealed that NDRG3 depletion significantly perturbed the methionine cycle, redirecting its flux towards branch pathways to upregulate several metabolites known to have hepatoprotective functions. Mechanistically, Ndrg3 LKO-dependent downregulation of glycine N-methyltransferase in the methionine cycle and the resultant elevation of the S-adenosylmethionine level appears to play a critical role in the restructuring of the methionine metabolism, eventually leading to the manifestation of GSD phenotypes in Ndrg3 LKO mice. Our results indicate that NDRG3 is required for the homeostasis of liver cell metabolism upstream of the glucose–glycogen flux and methionine cycle and suggest therapeutic values for regulating NDRG3 in disorders with malfunctions in these pathways.

Prognostic and biological role of the N-Myc downstream-regulated gene family in hepatocellular carcinoma

BACKGROUND

The N-Myc downstream-regulated gene (NDRG) family is comprised of four members (NDRG1-4) involved in various important biological processes. However, there is no systematic evaluation of the prognostic of the NDRG family in hepatocellular carcinoma (HCC).

AIM

To analyze comprehensively the biological role of the NDRG family in HCC.

METHODS

The NDRG family expression was explored using The Cancer Genome Atlas. DNA methylation interactive visualization database was used for methylation analysis of the NDRG family. The NDRG family genomic alteration was assessed using the cBioPortal. Single-sample Gene Set Enrichment Analysis was used to determine the degree of immune cell infiltration in tumors.

RESULTS

NDRG1 and NDRG3 were up-regulated in HCC, while NDRG2 was down-regulated. Consistent with expression patterns, high expression of NDRG1 and NDRG3 was associated with poor survival outcomes (P < 0.05). High expression of NDRG2 was associated with favorable survival (P < 0.005). An NDRG-based signature that statistically stratified the prognosis of the patients was constructed. The percentage of genetic alterations in the NDRG family varied from 0.3% to 11.0%, and the NDRG1 mutation rate was the highest. NDRG 1-3 expression was associated with various types of infiltrated immune cells. Gene ontology analysis revealed that organic acid catabolism was the most important biological process related to the NDRG family. Gene Set Enrichment Analysis showed that metabolic, proliferation, and immune-related gene sets were enriched during NDRG1 and NDRG3 high expression and NDRG2 low expression.

CONCLUSION

Overexpression of NDRG1 and NDRG3 and down-expression of NDRG2 are correlated with poor overall HCC prognosis. Our results may provide new insights into the indispensable role of NDRG1, 2, and 3 in the development of HCC and guide a promising new strategy for treating HCC.

Relationship between serum NDRG3 and papillary thyroid carcinoma

BACKGROUND

In recent years, papillary thyroid carcinoma is considered to be one of the fastest increaseing cancer. NDRG family member 3 (NDRG3) has been proposed as a molecular marker of tumor, and is expected to be used in clinic.

METHODS

Enzyme-linked immunosorbent assay was used to detect the serum NDRG3 expression in 81 papillary thyroid carcinoma cases, 75 benign thyroid nodules cases and 77 healthy control cases, respectively. Electrochemiluminescence method was applied to measure the levels of triiodothyronine, tetraiodothyronine, thyrotropin, thyroglobulin antibody and thyroid peroxidase antibody. Immunohistochemical staining was used to detect the expression of NDRG3 in papillary thyroid carcinoma, benign thyroid nodules and normal tissues adjacent to cancer.

RESULTS

The expression of serum triiodothyronine, tetraiodothyronine, thyrotropin, thyroglobulin antibody and thyroid peroxidase antibody and NDRG3 were significantly different among benign thyroid nodules, papillary thyroid carcinoma cases and healthy control groups (P <0.001). Only the expression of serum NDRG3 was significantly different between benign thyroid nodules and papillary thyroid carcinoma groups (P <0.001). Immunohistochemistry showed that NDRG3 was expressed in all three groups, the lowest in papillary thyroid carcinoma, the second in benign thyroid nodules, and the highest in normal tissues adjacent to cancer. Logistic regression analysis showed that serum NDRG3 was an independent protective factor for papillary thyroid carcinoma (OR =0.964, 95%CI =0.953 to 0.974, P <0.001). The ROC curve of non-papillary thyroid carcinoma diagnosed by serum NDRG3 showed the optimal cut-off value of 481.38 pg/ml, sensitivity of 72.4%, specificity of 90.1%, and the maximum area under the curve (AUC =0.902, 95%CI =0.863 to 0.940, P <0.001). The ROC curve of benign thyroid nodules diagnosed by serum NDRG3 showed the optimal critical value of 459.28 pg/ml, sensitivity of 81.3%, and specificity of 74.1% (AUC =0.863, 95%CI =0.808 to 0.919, P <0.001). The expression level of serum NDRG3 was significantly correlated with extrathyroid extensionand (P =0.007) and lymphatic metastasis of papillary thyroid carcinoma (P =0.019).

CONCLUSIONS

The decrease of NDRG3 expression can not only differential diagnosis benign thyroid nodules and papillary thyroid carcinoma, but also serve as a molecular marker for the diagnosis of papillary thyroid carcinoma.

A Genome-Wide Profiling of Glioma Patients with an IDH1 Mutation Using the Catalogue of Somatic Mutations in Cancer Database

Simple Summary

Glioma patients that present a somatic mutation in the isocitrate dehydrogenase 1 (IDH1) gene have a significantly better prognosis and overall survival than patients with the wild-type genotype. An IDH1 mutation is hypothesized to occur early during cellular transformation and leads to further genetic instability. A genome-wide profiling of glioma patients in the Catalogue of Somatic Mutations in Cancer (COSMIC) database was performed to classify the genetic differences in IDH1-mutant versus IDH1-wildtype patients. This classification will aid in a better understanding of how this specific mutation influences the genetic make-up of glioma and the resulting prognosis. Key differences in co-mutation and gene expression levels were identified that correlate with an improved prognosis.

Abstract

Gliomas are differentiated into two major disease subtypes, astrocytoma or oligodendroglioma, which are then characterized as either IDH (isocitrate dehydrogenase)-wild type or IDH-mutant due to the dramatic differences in prognosis and overall survival. Here, we investigated the genetic background of IDH1-mutant gliomas using the Catalogue of Somatic Mutations in Cancer (COSMIC) database. In astrocytoma patients, we found that IDH1 is often co-mutated with TP53, ATRX, AMBRA1, PREX1, and NOTCH1, but not CHEK2, EGFR, PTEN, or the zinc finger transcription factor ZNF429. The majority of the mutations observed in these genes were further confirmed to be either drivers or pathogenic by the Cancer-Related Analysis of Variants Toolkit (CRAVAT). Gene expression analysis showed down-regulation of DRG2 and MSN expression, both of which promote cell proliferation and invasion. There was also significant over-expression of genes such as NDRG3 and KCNB1 in IDH1-mutant astrocytoma patients. We conclude that IDH1-mutant glioma is characterized by significant genetic changes that could contribute to a better prognosis in glioma patients.

High expression of NDRG3 in osteoarthritis patients

BACKGROUND

Osteoarthritis (OA), as a common disease, seriously affects the quality of life of the victims, but its pathogenesis remains unclear. It has been confirmed that hypoxia-induced factor (HIF)-mediated hypoxia response plays an important role in the development and progression of OA. As a member of the N-myc downstream regulatory gene families, NDRG3 has been reported to independently regulate the hypoxic response of tumour cells, but the relationship between NDRG3 and OA development has not been reported so far.

METHODS

In this study, seven OA patients were admitted to Guizhou Provincial People's Hospital from January 2017 to December 2018. The OA group included 5 patients clinically diagnosed with hip/knee OA, which required arthroplasty. The normal group included 2 patients with no previous history of OA and rheumatoid arthritis, which required amputation due to trauma or tumour. The articular cartilage samples were collected to detect the expression of HIF-1α, HIF-2α and NDRG3 using immunohistochemical (IHC), haematoxylin and eosin (HE) and toluidine blue (TB) staining.

RESULTS

HE and TB staining indicated that the cartilage surface of the normal group was smooth and intact, with a columnar arrangement of hyaline chondrocytes, while the cartilage surface of the OA group was discontinuous, with cartilage missing and fibrous soft tissue growing into the defect site. HIF-1α staining was positive in both groups. Moreover, HIF-2α and NDRG3 staining was weakly positive in the normal group, but were uniformly and strongly positive in the OA group. The positively stained areas and integral optical density for NDRG3 were significantly greater in OA group than in the normal group (p < 0.05).

CONCLUSIONS

NDRG3 might be closely related to the development and progression of OA. However, the relationship between NDRG3 and OA, which is independent of the HIF pathway, warrants further research.

Upregulation of ITGBL1 predicts poor prognosis and promotes chemoresistance in ovarian cancer

BACKGROUND

Ovarian cancer remains one of the most lethal malignancies in women and the unfavorable prognosis and frequent recurrence are mainly due to the chemoresistance. However, the main mechanism underlying chemoresistance is still elusive.

OBJECTIVE

To determine the role and biological function of ITGBL1 in ovarian cancer chemoresistance.

METHODS

Immunohistochemical staining was used to determine the expression of ITGBL1 in ovarian cancer tissues. The association between ITGBL1 expression and clinicopathological features and survival was determined. Functional analysis including cell viability, apoptosis assays were performed after chemo drugs treatment to confirm the role of ITGBL1 in chemoresistance. In vivo tumor growth assay was used to detect the chemosensitivity of tumor cells. Western blot was used to detect the expression of indicated proteins.

RESULTS

We noticed that ITGBL1 expression was significantly upregulated in ovarian cancer tissues compared to that in adjacent non-cancer tissues and high expression of ITGBL1 was significantly associated with lymph node invasion and advanced FIGO stage. More importantly, high ITGBL1 was an independent prognostic factor of ovarian cancer. Further experiments demonstrated that ITGBL1 promoted tumor cell resistant to chemo drugs both in vitro and in vivo. Mechanically, we found that ITGBL1 could activate PI3K/Akt signaling and using PI3K/Akt inhibitor could abrogate ITGBL1 induced chemoresistance.

CONCLUSIONS

Our findings indicate that upregulation of ITGBL1 has important clinical significance and drives chemoresistance in ovarian cancer. Detection and depletion of ITGBL1 might be the potential approaches for diagnosis and therapy for ovarian cancer patients.

High NDRG3 expression facilitates HCC metastasis by promoting nuclear translocation of β-catenin

NDRG1 has been reported to exert pivotal roles in tumor progression and metastasis via Wnt/β-catenin signaling pathway. However, little is known about the role of NDRG3 in hepatocarcinogenesis despite its classification in the same subfamily of NDRG1. The present study was aimed to characterize the expression pattern and understand the biological roles of NDRG3 in hepatocarcinogenesis, as a means to exploit its therapeutic potential. It was observed that NDRG3 was up-regulated in HCC tissues and higher NDRG3 expression was associated with significantly shorter overall survival. Furthermore, a lower level of NDRG3 exhibited marked positive correlation with metastasis-free survival. In vitro and in vivo experiments revealed that knock-down of NDRG3 inhibits HCC metastasis and angiogenesis. We further demonstrated that activation of WNT/β-catenin signaling and enhanced CSC-like properties were responsible for NDRG3- mediated promoting effect on HCC. In conclusion, the principal findings demonstrated that high NDRG3 expression facilitates HCC metastasis via regulating the turnover of β-catenin, as well as provides a potential therapeutic target for future therapeutic interventions.

SPARC correlates with unfavorable outcome and promotes tumor growth in lung squamous cell carcinoma

Secreted protein acidic and rich in cysteine (SPARC) plays a crucial role in the malignant progression of a number of human cancers. However, the roles of SPARC in lung squamous cell carcinoma (LSCC) remain elusive. In this present study, we first detected SPARC expression and investigated the relationship between SPARC expression and the clinicopathological attributes of LSCC patients. Then we constructed SPARC-overexpression model in LSCC cell line to explore the characteristics of SPARC in LSCC development both in vitro and in vivo. The data demonstrated a remarkably higher level of SPARC in LSCC tissues than in corresponding non-cancerous tissues and elevated SPARC expression was significantly correlated with poor outcome in LSCC patients. Moreover, a serial of phenotypic experiments indicated that SPARC overexpression substantially facilitated the growth and inhibited the apoptosis in LSCC cells and xenografts. Taken together, our results suggest that SPARC is a novel prognostic marker for LSCC prognosis and SPARC significantly promotes LSCC tumorigenesis. Targeting SPARC may provide a novel therapeutic strategy for LSCC management.

SNHG20/miR-140-5p/NDRG3 axis contributes to 5-fluorouracil resistance in gastric cancer

5-fluorouracil (5-FU)-based chemotherapy is the first line treatment for advanced gastric cancer. However, the effectiveness of 5-FU is limited by drug resistance. The N-myc downstream-regulated gene, family member 3 (NDRG3) is a member of the NDRG family and has been implicated in numerous types of cancer. However, the role of NDRG3 in gastric cancer remains unclear. In the present study, NDRG3 mRNA expression in gastric cancer and adjacent normal tissues was analyzed using the Gene Expression Profiling Interactive Analysis web tool. NDRG3 expression was silenced using short hairpin RNAs to examine the effect of NDRG3 on the growth of gastric cancer cells. Potential regulators of NDRG3 were identified using the TargetScan and MicroRNA tools and verified by a luciferase assay and reverse transcription-quantitative PCR analysis. The current study demonstrated that NDRG3 was upregulated in gastric cancer specimens and promoted cell proliferation in gastric cancer cell lines. Furthermore, the present study revealed that the small nucleolar RNA host gene 20 (SNHG20)/microRNA (miR)-140-5p signaling pathway may regulate the expression of NDRG3. SNHG20 was revealed to be involved in mediating resistance to 5-FU in gastric cancer cell lines via NDRG3. In conclusion, the results of the present study suggest that the SNHG20/miR-140-5p/NDRG3 axis may be involved in mediating resistance to 5-FU in gastric cancer.

FLOT1 promotes tumor development, induces epithelial-mesenchymal transition, and modulates the cell cycle by regulating the Erk/Akt signaling pathway in lung adenocarcinoma

BACKGROUND

FLOT1 is a scaffolding protein of lipid rafts that is believed to be involved in numerous cellular processes. However, few studies have explored the function of FLOT1 in the development of lung adenocarcinoma (LUAD) and the underlying mechanisms of FLOT1 activity.

METHODS

FLOT1 knockdown and overexpression models were constructed via lentivirus. Cell growth, invasion, migration, and apoptosis were detected to evaluate the role of FLOT1 in LUAD development. Epithelial-mesenchymal transition (EMT) and cell cycle regulatory markers were then examined. Finally, the influence of FLOT1 on the Erk/Akt signaling pathway was investigated.

RESULTS

FLOT1 promoted cell growth, invasion, and migration and inhibited cell apoptosis. In addition, FLOT1 induced EMT and modulated the cell cycle by activating the Erk/Akt signaling pathway.

CONCLUSION

The findings indicate a significant role of FLOT1 in LUAD development. Targeting FLOT1 may be a potential therapeutic strategy for LUAD.

NDRG3 overexpression is associated with a poor prognosis in patients with hepatocellular carcinoma

N-myc downstream-regulated gene 3 (NDRG3), an important member of the NDRG family, is involved in cell proliferation, differentiation, and other biological processes. The present study analyzed NDRG3 expression in hepatocellular carcinoma (HCC) and explored the relationship between expression of NDRG3 in HCC patients and their clinicopathological characteristics. We performed quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR) analysis and immunohistochemistry (IHC) analyses on HCC tissues to elucidate NDRG3 expression characteristics in HCC patients. Kaplan-Meier survival curve and Cox regression analyses were used to evaluate the prognoses of 102 patients with HCC. The results revealed that compared with non-tumor tissues, HCC tissues showed significantly higher NDRG3 expression. In addition, our analyses showed that NDRG3 expression was statistically associated with tumor size (P=0.048) and pathological grade (P=0.001). Survival analysis and Kaplan-Meier curves revealed that NDRG3 expression is an independent prognostic indicator for disease-free survival (P=0.002) and overall survival (P=0.005) in HCC patients. The data indicate that NDRG3 expression may be considered as a oncogenic biomarker and a novel predictor for HCC prognosis.

Rab27b Is a Potential Indicator for Lymph Node Metastasis and Unfavorable Prognosis in Lung Adenocarcinoma

Rab27b is reported to associate with the development and progression of several types of human cancers. However, the relationship between Rab27b expression and the clinical characteristics of lung adenocarcinoma (LUAD) is rarely explored. In this present study, the TCGA database was consulted, followed by one-step quantitative reverse transcription polymerase chain reaction (qPCR), Western blot, and immunohistochemistry (IHC) analyses in LUAD cell lines and tissue samples. Rab27b expression levels were statistically higher in LUAD cell lines and tissue samples compared with a noncancerous cell line and tissue samples (p < 0.05). Rab27b expression was statistically correlated with lymph node metastasis (p = 0.016) and TNM stage (p = 0.019). Survival analysis and Kaplan-Meier curve revealed that Rab27b expression (p = 0.006) and TNM stage (p = 0.027) were independently associated with the unfavorable overall survival of patients with LUAD. These results indicate that high expression of Rab27b correlates with malignant attributes of LUAD and Rab27b may be identified as a potential indicator of metastasis and prognosis for LUAD.