Expression of N-myc downstream-regulated gene 1 in primary gallbladder carcinoma and its correlation with clinicopathological features and clinical outcome

Prognostic value of serum high-density lipoprotein cholesterol in patients with gallbladder cancer

OBJECTIVES

the aim of this study was to evaluate the prognostic significance of preoperative serum lipid in patients with gallbladder cancer (GBC).

METHODS

ninety-nine patients with GBC between October 2009 and December 2013 were reviewed in this retrospective study. Total serum cholesterol (TC), total triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoprotein A (Apo-A), apolipoprotein B (Apo-B) and free fatty acids (FFA) were measured before surgery. The correlation of serum lipid levels with clinical data, including gender, age, tumor size, lymph nodes metastasis, tumor differentiation, distant metastasis and TNM stage were analyzed by univariate and multivariate survival analysis to evaluate independent prognostic factors.

RESULTS

compared with the normal HDL-C group (n = 57), the overall survival rate among GBC patients with low HDL-C levels (n = 42) was reduced (p < 0.05). However, there were no significant differences in overall survival for patients with different levels of TC, TG, Apo-A, Apo-B, LDL-C or FFA. The serum level of HDL-C was associated with TNM stage (p < 0.05) and distant metastasis (p < 0.001). The multivariate prognosis analysis showed that HDL-C and lymph nodes metastasis were independent prognostic factors (p < 0.05). A prognostic evaluation model based on HDL-C and lymph nodes metastasis was established.

CONCLUSION

preoperative serum HDL-C level was closely associated with distant metastasis of patients with GBC. HDL-C level may be a valuable prognostic factor for GBC patients. The combination of HDLC and lymph nodes metastasis can better predict the prognosis of GBC.

Pharmacological targeting and the diverse functions of the metastasis suppressor, NDRG1, in cancer

N-myc downstream regulated gene-1 (NDRG1) is a potent metastasis suppressor that is regulated by hypoxia, metal ions including iron, the free radical nitric oxide (NO^.), and various stress stimuli. This intriguing molecule exhibits diverse functions in cancer, inhibiting epithelial-mesenchymal transition (EMT), cell migration and angiogenesis by modulation of a plethora of oncogenes via cellular signaling. Thus, pharmacological targeting of NDRG1 signaling in cancer is a promising therapeutic strategy. Of note, novel anti-tumor agents of the di-2-pyridylketone thiosemicarbazone series, which exert the "double punch" mechanism by binding metal ions to form redox-active complexes, have been demonstrated to markedly up-regulate NDRG1 expression in cancer cells. This review describes the mechanisms underlying NDRG1 modulation by the thiosemicarbazones and the diverse effects NDRG1 exerts in cancer. As a major induction mechanism, iron depletion appears critical, with NO^. also inducing NDRG1 through its ability to bind iron and generate dinitrosyl-dithiol iron complexes, which are then effluxed from cells. Apart from its potent anti-metastatic role, several studies have reported a pro-oncogenic role of NDRG1 in a number of cancer-types. Hence, it has been suggested that NDRG1 plays pleiotropic roles depending on the cancer-type. The molecular mechanism(s) underlying NDRG1 pleiotropy remain elusive, but are linked to differential regulation of WNT signaling and potentially differential interaction with the tumor suppressor, PTEN. This review discusses NDRG1 induction mechanisms by metal ions and NO^. and both the anti- and possible pro-oncogenic functions of NDRG1 in multiple cancer-types and compares the opposite effects this protein exerts on cancer progression.

The prognostic value of decreased NDRG1 expression in patients with digestive system cancers: A meta-analysis

BACKGROUND

Digestive system cancers are recognized as associated with high morbidity and mortality. It is generally accepted that N-myc downstream-regulated gene 1 (NDRG1) is aberrantly overexpressed or downregulated in digestive system cancers, and its prognostic value remains controversial. Accordingly, we herein conducted a meta-analysis to explore whether NDRG1 expression is correlated with overall survival (OS) and clinicopathological characteristics of patients with digestive system cancers.

METHODS

We systematically searched PubMed, EMBASE, and Web of Science for eligible studies up to June 6, 2017. In all, 19 publications with 21 studies, were included.

RESULTS

The pooled results showed that low NDRG1 expression was significantly associated with worse OS in colorectal cancer (pooled HR = 1.67, 95% CI: 1.22-2.28, P < .001) and pancreatic cancer (pooled HR = 1.87, 95% CI: 1-3.5, P < .0001). Moreover, the relationships between low NDRG1 expression and higher OS ratio of patients with liver cancer (pooled HR = 0.44, 95% CI: 0.32-0.62, P = .009) and gallbladder cancer (pooled HR = 0.56, 95% CI: 0.23-1.38, P = .01) were observed. Nevertheless, no significant association was observed between low NDRG1 expression and OS in gastric cancer (pooled HR = 0.81, 95% CI: 0.45-1.43, P = .46) or esophageal cancer (pooled HR = 0.76, 95% CI: 0.26-2.24, P = .62).

CONCLUSION

The prognostic significance of NDRG1 expression varies according to cancer type in patients with DSCs. Considering that several limitations existed in this meta-analysis, more studies are required to further assess the prognostic value of NDRG1 expression in patients with DSCs and relevant mechanisms.

Proteomic identification of tumor biomarkers associated with primary gallbladder cancer

AIM: To identify potential biomarkers of primary gallbladder cancer (PGC).

METHODS: Fresh PGC, cholecystitis and normal gallbladder tissue specimens collected from 10 patients, respectively, were subjected to comparative proteomic analysis. The proteomic patterns of PGC were compared with those of cholecystitis and normal gallbladder tissues using two-dimensional gel electrophoresis (2-DE). The differentially expressed proteins were then identified using a MALDI-TOF mass spectrometer (MS) and database searches. To further validate these proteins, 20 samples of PGC tissues and normal tumor-adjacent tissues were collected for Western blot, quantitative real-time PCR, and immunohistochemical staining assay.

RESULTS: Seven differentially expressed protein spots were detected by 2-ED analysis by comparing the average maps of PGC, cholecystitis and normal gallbladder tissues. Six of the seven differentially expressed proteins were identified using MALDI-TOF MS, with three overexpressed and three underexpressed in PGC tissue. Protein levels of annexin A4 (ANXA4) were significantly elevated, and heat shock protein 90-beta (Hsp90β) and dynein cytoplasmic 1 heavy chain 1 (Dync1h1) were decreased in PGC tissues relative to the normal tumor-adjacent tissues as shown by Western blot analysis. However, levels of actin, aortic smooth muscle and gamma-actin were unchanged. In addition, the mRNA levels of all 5 proteins showed similar changes to those of the protein levels (P < 0.01). Further validation by immunohistochemical analysis showed the upregulated expression of ANXA4 and decreased expression of Hsp90β and Dync1h1 in the cytoplasm of PGC tissues relative to the normal tumor-adjacent tissues.

CONCLUSION: Three proteins are identified as potential biomarkers of PGC using proteomic analysis. The functions of these proteins in the carcinogenesis of PGC remain to be studied.

Molecular functions of the iron-regulated metastasis suppressor, NDRG1, and its potential as a molecular target for cancer therapy

N-myc down-regulated gene 1 (NDRG1) is a known metastasis suppressor in multiple cancers, being also involved in embryogenesis and development, cell growth and differentiation, lipid biosynthesis and myelination, stress responses and immunity. In addition to its primary role as a metastasis suppressor, NDRG1 can also influence other stages of carcinogenesis, namely angiogenesis and primary tumour growth. NDRG1 is regulated by multiple effectors in normal and neoplastic cells, including N-myc, histone acetylation, hypoxia, cellular iron levels and intracellular calcium. Further, studies have found that NDRG1 is up-regulated in neoplastic cells after treatment with novel iron chelators, which are a promising therapy for effective cancer management. Although the pathways by which NDRG1 exerts its functions in cancers have been documented, the relationship between the molecular structure of this protein and its functions remains unclear. In fact, recent studies suggest that, in certain cancers, NDRG1 is post-translationally modified, possibly by the activity of endogenous trypsins, leading to a subsequent alteration in its metastasis suppressor activity. This review describes the role of this important metastasis suppressor and discusses interesting unresolved issues regarding this protein.

Aberrant NDRG1 methylation associated with its decreased expression and clinicopathological significance in breast cancer

Background

Cancer cell differentiation is an important characteristic of malignant tumor and has a great impact on prognosis and therapeutic decision for patients. The N-myc downstream regulated gene 1 (NDRG1), a putative tumor suppression gene, is involved in the regulation of human cell differentiation and metastasis in various cancers. Changes in the status of methylation of the NDRG1 gene have not been studied in detail in human breast cancer.

Results

The MDA-MB-231 breast tumor cell line could express NDRG1. However, it was only expressed after treatment with 5-Aza-2'-deoxycytidine (AZA) in T47D cell line, which revealed that NDRG1 expression could modulated by DNA methylation. Therefore, the fragment surrounding the transcript start site of NDRG1 gene promoter was cloned after sodium bisulfite DNA treatment. A high density (66%) of methylation for human NDRG1 gene promoter was detected in T47D; however, there was only 16% of methylated CpG dinucleotides in the NDRG1 gene promoter in MDA-MB-231. DNA methylation in the NDRG1 promoter was detected in 31.1% of primary breast cancer samples. Furthermore, the NDRG1 promoter methylation correlated with the Tumor Node Metastasis (TNM) at stage III/IV, metastasis, lymph invasion, moderate and poor histological grade in the breast cancer patients.

Conclusion

These findings suggest that the DNA methylation status of NDRG1 gene may play an important role in the pathogenesis and/or development of breast cancer, and the expression could be regulated by aberrant DNA methylation.