Extracellular NM23 Signaling in Breast Cancer: Incommodus Verum. Cancers (Basel). 2011;3:2844-2857. [PMID: 22091350 DOI: 10.3390/cancers3032844]

Metastasis suppressor genes and their role in the tumor microenvironment

The metastatic cascade is a complex process with multiple factors contributing to the seeding and growth of cancer cells at metastatic sites. Within this complex process, several genes have been identified as metastasis suppressors, playing a role in the inhibition of metastasis. Interestingly, some of these genes have been shown to also play a role in regulating the tumor microenvironment. In this review, we comment on the recent developments in the biology of metastasis suppressor genes and their crosstalk with the microenvironment.

Evaluation of Metastasis Suppressor Genes Expression and In Vitro Anti-Cancer Effects of Zinc Oxide Nanoparticles in Human Breast Cancer Cell Lines MCF-7 and T47D

Background:

Metallic nanoparticles are useful materials to be applied in biomedical research. In this study, the possible apoptotic and anti-metastatic activity of Zinc Oxide Nanoparticles (ZnONPs) was assessed in breast cancer cells.

Methods:

First, in vitro cell viability was investigated by MTT assay in two human breast cancer cells (MCF-7 and T47D) and normal Human Embryonic Kidney (HEK293) cells at 37°C overnight. Apoptosis induced by ZnONPs was evaluated by annexin V/PI staining, cell cycle analysis and caspase assay in cancerous cells. Moreover, quantitative real-time PCR was employed for the detection of two metastasis suppressor genes (KAI-1 and NM23) expression in cancerous cells.

Results:

Data demonstrated that ZnONPs exert a dose-dependent inhibitory effect on the viability of T47D and MCF-7 cells, while no cytotoxic effect was observed on normal HEK293 cells. The mRNA expression levels of KAI-1 and non-metastatic protein (NM23) genes were up-regulated in ZnONP-exposed cancerous cells. ZnONPs were also found to enhance the apoptosis properties of cells by annexin V/PI staining, and caspase assay in cancerous cells. Furthermore, ZnONPs can increase sub-G1 population as compared to negative control.

Conclusion:

Our findings showed that ZnONPs induce apoptotic activity and can modulate metastasis by up-regulating of KAI-1 and NM23 gene expression in two breast cancer (MCF-7 and T47D) cells.

The multiple regulation of metastasis suppressor NM23-H1 in cancer

Metastasis is one of the leading causes of mortality in cancer patients. As the firstly identified metastasis suppressor, NM23-H1 has been endowed with expectation as a potent target in metastatic cancer therapy during the past decades. However, many challenges impede its clinical use. Accumulating evidence shows that NM23-H1 has a dichotomous role in tumor metastasis as a suppressor and promoter. It has potentially attributed to its versatile biochemical characteristics such as nucleoside diphosphate kinase (NDPK) activity, histidine kinase activity (HPK), exonuclease activity, and protein scaffold, which further augment the complexity and uncertainty of its physiological function. Simultaneously, tumor cells have evolved multiple ways to regulate the expression and function of NM23-H1 during tumorigenesis and metastasis. This review summarized and discussed the regulatory mechanisms of NM23-H1 in cancer including transcriptional activation, subcellular location, enzymatic activity, and protein degradation, which significantly modulate its anti-metastatic function.

Association of NM23 polymorphisms and clinicopathological features and recurrence of invasive pituitary adenomas

BACKGROUND

Pituitary adenomas (PAs) are intracranial tumors, deriving from anterior pituitary cells. Previously, expression of non-metastasis-23 (NM23) gene has been shown to correlate with the progression of PAs. In this study, we aim to determine whether there is association between specific NM23 polymorphisms and invasive pituitary adenoma (IPA).

METHODS

Genotypes of rs2302254 and rs16949649 of NM23 were identified in the peripheral venous blood of patients by PCR-RLFP. Next, the correlation between specific genotypes of rs2302254 and rs16949649 and risk of IPA was investigated. Finally, the correlations between NM23 polymorphisms and tumor size, Ki67 LI and recurrence of IPA were analyzed with 3 to 24 months follow-up for the enrolled patients.

RESULTS

We observed that the TT genotype at rs16949649 correlated closely with a high risk of IPA, while CC and CT genotypes reduced the risk of IPA. CC genotype at rs2302254 increased the risk of IPA, while CT and TT genotypes reduced the risk of IPA. T_rs16949649C_rs2302254 haplotype of NM23 was found to be a high-risk haplotype for IPA. TT genotype at rs16949649 and CC genotype at rs2302254 were associated with higher rates of tumors larger than 20 mm, Ki67 LI and tumor recurrence.

CONCLUSION

Taken together, the present study provides evidence that NM23 polymorphisms are closely associated with the incidence and recurrence of IPA. Specifically, TT genotype at rs16949649 and CC genotype at rs2302254 are risk factors of IPA. NM23 polymorphisms could therefore be used as a reference for clinical diagnosis and prognosis of IPA.

Imatinib induces up-regulation of NM23, a metastasis suppressor gene, in human Hepatocarcinoma (HepG2) Cell Line

AIM

The present study investigated the anti-tumor activity of Imatinib mesylate through modulation of NM23 gene expression in human hepatocellular carcinoma (HepG2) cell line.

BACKGROUND

Hepatocellular carcinoma (HCC) is considered to be the third leading cause of cancer related death worldwide. Down regulation of NM23, a metastasis suppressor gene, has been associated with several types of malignant cancer. Recently, effects of Imatinib mesylate, a first member of tyrosine kinases inhibitors, were indicated in research and treatment of different malignant tumors.

METHODS

Cell viability was quantitated by MTT assay after HepG2 cells exposure to Imatinib mesylate at various concentrations of 0, 1.56, 3.125, 6.25, 12.5, 25,50μM for 24 hours. Also, quantitative real time PCR technique was applied for the detection of NM23 gene expression in HepG2 cell line.

RESULTS

There was a dose dependent increase in the cytotoxicity effect of imatinib. The real time PCR results demonstrated that inhibitory effect of Imatinib mesylate on viability via up regulation of NM23 gene expression compared to GAPDH gene (internal control gene) in cancer cells.

CONCLUSION

According to our findings, imatinib can modulate metastasis by enhancing Nm23 gene expression in human hepatocellular carcinoma (HepG2) cell line.

Nucleoside diphosphate kinase B deficiency causes a diabetes-like vascular pathology via up-regulation of endothelial angiopoietin-2 in the retina

AIMS

Nucleoside diphosphate kinase B (NDPKB) is capable of maintaining the cellular nucleotide triphosphate pools. It might therefore supply UTP for the formation of UDP-GlcNAc from glucose. As NDPKB contributes to vascular dysfunction, we speculate that NDPKB might play a role in microangiopathies, such as diabetic retinopathy (DR). Therefore, we investigated the impact of NDPKB on retinal vascular damage using NDPKB(-/-) mice during development of DR and its possible mechanisms.

METHODS

Pericyte loss and acellular capillary (AC) formation were assessed in streptozotocin-induced diabetic NDPKB(-/-) and wild-type (WT) mice. Expression of angiopoietin-2 (Ang2) and protein N-acetylglucosamine modification (GlcNAcylation) were assessed by western blot and/or immunofluorescence in the diabetic retinas as well as in endothelial cells depleted of NDPKB by siRNA and stimulated with high glucose.

RESULTS

Similar to diabetic WT retinas, non-diabetic NDPKB(-/-) retinas showed a significant decrease in pericyte coverage in comparison with non-diabetic WT retinas. Hyperglycemia further aggravates pericyte loss in diabetic NDPKB(-/-) retinas. AC formation was detected in the diabetic NDPKB(-/-) retinas. Similar to hyperglycemia, NDPKB deficiency induced Ang2 expression and protein GlcNAcylation that were not further altered in the diabetic retinas. In cultured endothelial cells, stimulation with high glucose and NDPKB depletion comparably increased Ang2 expression and protein GlcNAcylation.

CONCLUSIONS

Our data identify NDPKB as a protective factor in the retina, which controls Ang2 expression and the hexosamine pathway. NDPKB-deficient mice are a suitable model for studying mechanisms underlying diabetic retinal vascular damage.

Blockade of extracellular NM23 or its endothelial target slows breast cancer growth and metastasis

BACKGROUND

Nucleoside Diphosphate Kinase (NDPK), described as NM23 a metastasis suppressor, is found in the culture medium of cancer cells lines suggesting that the kinase may have an extracellular role. We propose that extracellular NM23 released from breast cancers in vivo stimulates tumor cell migration, proliferation and endothelial cell angiogenesis in support of metastasis development.

METHODS

NM23 in the bloodstream of immunocompromised mice carrying human triple-negative breast cancers or in breast cancer patients was measured by ELISA. Primary and metastatic tumor development, the impact of blockade of NM23 and/or its stimulation of nucleotide receptors were measured using in vivo imaging. NM23 expression data in the Curtis breast dataset was examined to test our hypothesis that NM23 may play a mechanistic role in breast cancer development.

RESULTS

SCID mice carrying metastatic MDA-MB-231Luc+ triple-negative human breast tumor cells elaborate NM23 into the circulation correlated with primary tumor growth. Treatment of mice with the NM23 inhibitor ellagic acid (EA) or the purinergic receptor antagonist MRS2179 slowed primary tumor growth. At 16 weeks following implantation, lung metastases were reduced in mice treated with EA, MRS2179 or the combination. Expression of NM23 in the Curtis breast dataset confirmed a likely role for NM23 in tumor metastasis.

CONCLUSIONS

Extracellular NM23 may constitute both a biomarker and a therapeutic target in the management of breast cancer.

Relationship between the nm23 gene and prognosis of esophageal carcinoma

The occurrence and development of esophageal cancer are the result of multiple gene interactions, and the nm23 gene is involved in the regulation of tumor cell metastasis and can inhibit lymph node metastasis. The detection of the change in the nm23 gene can help predict the presence of lymph node metastasis or not in esophageal carcinoma. Moreover, nm23 is an important indicator for prognosis evaluation in esophageal carcinoma.

Targeted silencing of MART-1 gene expression by RNA interference enhances the migration ability of uveal melanoma cells

Uveal melanoma (UM) is the most common primary intraocular malignancy and the leading potentially fatal primary intraocular disease in adults. Melanoma antigen recognized by T-cells (MART-1) has been studied extensively as a clinically important diagnostic marker for melanoma, however, its biological function remains unclear. In the present study, the UM cell line SP6.5, which showed a high level of MART-1 expression, was subjected to small interfering RNA-mediated silencing of MART-1. Silencing of MART-1 expression increased the migration ability of SP6.5 cells and down-regulated the expression of the metastasis suppressor NM23. Our results suggest that MART-1 is a candidate target for the development of therapeutic strategies for UM and in particular for the suppression of metastasis associated with this malignancy.

Targeting tumor metastasis by regulating Nm23 gene expression

The Nm23 gene is a metastatic suppressor identified in a melanoma cell line and expressed in different tumors where their levels of expression are associated with reduced or increased metastatic potential. Nm23 is one of the over 20 metastasis suppressor genes (MSGs) confirmed in vivo. It is highly conserved from yeast to human, implying a critical developmental function. Tumors with alteration of the p53 gene and reduced expression of the Nm23 gene are more prone to metastasis. Nm23-H1 has 3'-5' exonuclease activity. This review focuses on the role of Nm23 in cancer progression and also a potential novel target for cancer therapy.