Differential regulation of NM23-H1 under hypoxic and serum starvation conditions in metastatic cancer cells and its implication in EMT

Molecular interaction of metastasis suppressor genes and tumor microenvironment in breast cancer

Breast cancer (BC) is a leading cause of cancer-related deaths in women worldwide where the process of metastasis is a major contributor to the mortality associated with this disease. Metastasis suppressor genes are a group of genes that play a crucial role in preventing or inhibiting the spread of cancer cells. They suppress the metastasis process by inhibiting colonization and by inducing dormancy. These genes function by regulating various cellular processes in the tumor microenvironment (TME), such as cell adhesion, invasion, migration, and angiogenesis. Dysregulation of metastasis suppressor genes can lead to the acquisition of an invasive and metastatic phenotype and lead to poor prognostic outcomes. The components of the TME generally play a necessary in the metastasis progression of tumor cells. This review has identified and elaborated on the role of a few metastatic suppressors associated with the TME that have been shown to inhibit metastasis in BC by different mechanisms, such as blocking certain cell signaling molecules involved in cancer cell migration, invasion, enhancing immune surveillance of cancer cells, and promoting the formation of a protective extracellular matrix (ECM). Understanding the interaction of metastatic suppressor genes and the components of TME has important implications for the development of novel therapeutic strategies to target the metastatic cascade. Targeting these genes or their downstream signaling pathways offers a promising approach to inhibiting the spread of cancer cells and improves patient outcomes.

Heterochiral dipeptide d-phenylalanyl- l-phenylalanine (H-D Phe-L Phe-OH) as a potential inducer of metastatic suppressor NM23H1 in p53 wild-type and mutant cells

In recent years, significant progress has been made to the use-case of small peptides because of their diversified edifice and hence their versatile application scope in cancer therapy. Here we identify the heterochiral dipeptide H-^D Phe-^L Phe-OH (F1) as a potent inducer of the metastatic suppressor NM23H1. We divulge the effect of F1 on the major EMT/metastasis-associated genes and the implications on the invasion and migration ability of cancer cells. The anti-invasive potential of F1 was directly correlated with NM23H1 expression. Mechanistically, F1 treatment elevated p53 levels as validated by localization and transcriptional studies. In the NM23H1 knockdown condition, F1 failed to induce any p53 expression/nuclear localization, indicating that the upregulation in p53 expression by F1 is NM23H1 dependent. We also demonstrate how the antimetastatic potential of F1 is primarily mediated through NM23H1 irrespective of the p53 status of the cell. However, both NM23H1 and a functional p53 protein in conjunction govern the apoptotic and cytostatic potential of F1. Coimmunoprecipitation studies unraveled the augmentation of the p53 and NM23H1 interaction in p53 wild-type cells. However, in p53 mutated cells, no such enrichment was evidenced. We employed mouse isogenic cell lines (4T-1 and 4T-1 p53) to determine the in vivo efficacy of F1 (spontaneous and experimental models). Decreased tumor volume in the cohort injected with 4T-1 p53 cells demonstrated that while the antimetastatic potential of F1 was reliant on NM23H1, p53 activation was required for ablation of primary tumor burden. Our findings unravel that F1 treatment induces significant abrogation of the migration, invasion and metastatic potential of both p53 wild-type and p53 deficient cancers mediated through NM23H1.

Targeting FHL2-E-cadherin axis by miR-340-5p attenuates colon cancer cell migration and invasion

Convincing data has suggested that four and a half LIM domain 2 protein (FHL2) serves a key function in cancer cell metastasis and that microRNA (miR)-340-5p can regulate cancer cell migration. The current study hypothesized that targeting FHL2 expression by miR-340-5p in colon cancer may attenuate colon cancer cell migration and invasion. FHL2 expression was therefore assessed in colon cancer microarray datasets using Qlucore omics explorer as well as in HT-29 and AZ-97 colon cancer cell lines via reverse transcription-quantitative PCR (RT-qPCR). Colon cancer cell migration and invasion were evaluated in the presence of miR-340-5p mimic, mimic control or mimic with a target site blocker. Confocal microscopy and RT-qPCR were subsequently performed to assess FHL2, E-cadherin (E-cad) protein and mRNA expression in colon cancer cells. Microarray dataset analysis revealed that FHL2 expression was lower in primary colon cancer cells compared with normal colonic mucosa. It was revealed that the expression of miR-340-5p and FHL2 were inversely related in serum-grown and low-serum conditions in HT-29 and AZ-97 cells. Short-time serum exposure to low-serum grown cells induced FHL2 expression. Transfection of HT-29 cells with miR-340-5p mimic not only decreased serum-induced expression of FHL2 but also decreased cancer cell migration and invasion. Bioinformatics analysis revealed that FHL2 mRNA had one putative binding site for miR-340-5p at the 3-untranslated region. Blocking of the target site using a specific blocker reverted miR-340-5p mimic-induced inhibition of FHL2 expression and cancer cell migration and invasion. Confocal microscopy confirmed that the reduction of FHL2 expression by miR-340-5p mimic also reversed serum-induced E-cad disruption and that the target site blocker abrogated the effect of miR-340-5p. The current results suggested that miR-340-5p could be used to antagonize colon cancer cell metastasis by targeting the FHL2-E-cad axis.

Spontaneous Cell Detachment and Reattachment in Cancer Cell Lines: An In Vitro Model of Metastasis and Malignancy

There is an unmet need for simplified in vitro models of malignancy and metastasis that facilitate fast, affordable and scalable gene and compound analysis. "Adherent" cancer cell lines frequently release "free-floating" cells into suspension that are viable and can reattach. This, in a simplistic way, mimics the metastatic process. We compared the gene expression profiles of naturally co-existing populations of floating and adherent cells in SW620 (colon), C33a (cervix) and HeLa (cervix) cancer cells. We found that 1227, 1367 and 1333 genes were at least 2-fold differentially expressed in the respective cell lines, of which 122 were shared among the three cell lines. As proof of principle, we focused on the anti-metastatic gene NM23-H1, which was downregulated both at the RNA and protein level in the floating cell populations of all three cell lines. Knockdown of NM23-H1 significantly increased the number of floating (and viable) cells, whereas overexpression of NM23-H1 significantly reduced the proportion of floating cells. Other potential regulators of these cellular states were identified through pathway analysis, including hypoxia, mTOR (mechanistic target of rapamycin), cell adhesion and cell polarity signal transduction pathways. Hypoxia, a condition linked to malignancy and metastasis, reduced NM23-H1 expression and significantly increased the number of free-floating cells. Inhibition of mTOR or Rho-associated protein kinase (ROCK) significantly increased cell death specifically in the floating and not the adherent cell population. In conclusion, our study suggests that dynamic subpopulations of free-floating and adherent cells is a useful model to screen and identify genes, drugs and pathways that regulate the process of cancer metastasis, such as cell detachment and anoikis.

MicroRNA-340-5p inhibits colon cancer cell migration via targeting of RhoA

Colon cancer is the third most common cancer and a significant cause of cancer-related deaths worldwide. Metastasis is the most insidious aspect of cancer progression. Convincing data suggest that microRNAs (miRs) play a key function in colon cancer biology. We examined the role of miR-340-5p in regulating RhoA expression as well as cell migration and invasion in colon cancer cells. Levels of miR-340-5p and RhoA mRNA varied inversely in serum-free and serum-grown HT-29 and AZ-97 colon cancer cells. It was found transfection with miR-340-5p not only decreased expression of RhoA mRNA and protein levels in HT-29 cells but also reduced colon cancer cell migration and invasion. Bioinformatics analysis predicted one putative binding sites at the 3'-UTR of RhoA mRNA. Targeting this binding site with a specific blocker reversed mimic miR-340-5p-induced inhibition of RhoA activation and colon cancer cell migration and invasion. These novel results suggest that miR-340-5p is an important regulator of colon cancer cell motility via targeting of RhoA and further experiments are warranted to evaluate the role of miR-340-5p in colon cancer metastasis.

Negative Effect of Reduced NME1 Expression on Recurrence-Free Survival in Early Stage Non-Small Cell Lung Cancer

This study aimed to understand whether the effect of non-metastatic cells 1 (NME1) on recurrence-free survival (RFS) in early stage non-small cell lung cancer (NSCLC) can be modified by β-catenin overexpression and cisplatin-based adjuvant chemotherapy. Expression levels of NME1 and β-catenin were analyzed using immunohistochemistry in formalin-fixed paraffin-embedded tissues from 425 early stage NSCLC patients. Reduced NME1 expression was found in 39% of samples. The median duration of follow-up was 56 months, and recurrence was found in 186 (44%) of 425 patients. The negative effect of reduced NME1 expression on RFS was worsened by cisplatin-based adjuvant chemotherapy (adjusted hazard ratio = 3.26, 95% CI = 1.16–9.17, p = 0.03). β-catenin overexpression exacerbated the effect of reduced NME1 expression on RFS and the negative effect was greater when receiving cisplatin-based adjuvant chemotherapy: among patients treated with cisplatin-based adjuvant chemotherapy, hazard ratios of patients with reduced NME1 expression increased from 5.59 (95% confidence interval (CI) = 0.62–50.91, p = 0.13) to 15.52 (95% CI = 2.94–82.38, p = 0.001) by β-catenin overexpression, after adjusting for confounding factors. In conclusion, the present study suggests that cisplatin-based adjuvant chemotherapy needs to be carefully applied to early stage NSCLC patients with overexpressed β-catenin in combination with reduced NME1 expression.

miR-141-3p promotes proliferation and metastasis of nasopharyngeal carcinoma by targeting NME1

PURPOSE

This study aimed to investigate the expression and biological function of miR-141-3p in nasopharyngeal carcinoma (NPC) via targeting neoplasm metastasis 1 (NME1).

MATERIALS AND METHODS

The expression of miR-141-3p and NME1 in 5-8F, C666-1, CNE-1, CNE-2, 6-10B and NP69 nasopharyngeal epithelial cells were detected using real-time Polymerase Chain Reaction (real-time PCR) and western blot, respectively. Cell proliferation was detected using Cell Counting Kit-8 (CCK-8), and the metastasis was detected using Transwell. The binding of miR-141-3p to NME1 was detected by dual luciferase reporter gene detection system. The effects of miR-141-3p on tumor growth were also determined in vivo.

RESULTS

The results showed that the expression of miR-141-3p significantly increased in various tumor cell lines and the expression of NME1 was higher in NP69 cells and lower in 5-8F cells, which had significant negative correlation. Furthermore, the expression of NME1 was significantly reduced after transfection of miR-141-3p and miR-141-3p promoted cell proliferation and metastasis. The double luciferase reporter gene detection system confirmed that NME1 was the target gene of miR-141-3p. Knockout of NME1 promoted the proliferation and metastasis of NP69 or 6-10B cells and the activation of p-Akt, which were abrogated by miR-141-3p. In vivo, the tumor volumes and weights in the miR-141-3p group significantly increased followed by down-regulation of NME1 and activation of p-Akt.

CONCLUSIONS

We confirmed that miR-141-3p promotes the proliferation and metastasis of NPC by targeting NME1.

In vitro and in vivo studies of cancer cell behavior under nutrient deprivation

Cancer cells are confronted with nutrient deprivation because of high proliferation rate, especially at the early stage of their development. There is a frequent assumption that nutrient deprivation decreases the basal activity of cancer cells. Contrarily, there are recent evidence suggesting that cancer cells are able to modulate signaling pathways to adapt with new condition and continue their survival. This property of cancer cells is believed to be one of the prerequisites for cancer progression and chemoresistance. Moreover, recent experiments show that serum starvation in vitro as a mimic situation of nutrient deprivation in vivo triggers different signaling pathways leading to changes in cancer cell behavior, which may interfere with experimental results. Considering these facts, a better understanding of the effect of nutrient deprivation on cancer cell behavior will help us to give more accurate conclusions regarding results of in vitro studies and also to develop new strategies to treat different cancers in vivo.

Compartmentalization of adenosine metabolism in cancer cells and its modulation during acute hypoxia

Extracellular adenosine mediates diverse anti-inflammatory, angiogenic and vasoactive effects, and has become an important therapeutic target for cancer, which has been translated into clinical trials. This study was designed to comprehensively assess adenosine metabolism in prostate and breast cancer cells. We identified cellular adenosine turnover as a complex cascade, comprising (1) the ectoenzymatic breakdown of ATP via sequential ecto-nucleotide pyrophosphatase/phosphodiesterase-1 (NPP1, officially known as ENPP1), ecto-5'-nucleotidase (CD73, also known as NT5E), and adenosine deaminase reactions, and ATP re-synthesis through a counteracting adenylate kinase and members of the nucleoside diphosphate kinase (NDPK, also known as NME/NM23) family; (2) the uptake of nucleotide-derived adenosine via equilibrative nucleoside transporters; and (3) the intracellular adenosine phosphorylation into ATP by adenosine kinase and other nucleotide kinases. The exposure of cancer cells to 1% O2 for 24 h triggered an ∼2-fold upregulation of CD73, without affecting nucleoside transporters, adenosine kinase activity and cellular ATP content. The ability of adenosine to inhibit the tumor-initiating potential of breast cancer cells via a receptor-independent mechanism was confirmed in vivo using a xenograft mouse model. The existence of redundant pathways controlling extracellular and intracellular adenosine provides a sufficient justification for reexamination of the current concepts of cellular purine homeostasis and signaling in cancer.This article has an associated First Person interview with the first author of the paper.

Par-4 mediated Smad4 induction in PDAC cells restores canonical TGF-β/ Smad4 axis driving the cells towards lethal EMT

Deregulation of TGF-β signaling is intricately engrossed in the pathophysiology of pancreatic adenocarcinomas (PDACs). The role of TGF-β all through pancreatic cancer initiation and progression is multifarious and somewhat paradoxical. TGF-β plays a tumor suppressive role in early-stage pancreatic cancer by promoting apoptosis and inhibiting epithelial cell cycle progression, but incites tumor promotion in late-stage by modulating genomic instability, neo-angiogenesis, immune evasion, cell motility, and metastasis. Here, we provide evidences that Par-4 acts as one of the vital mediators to regulate TGF-β/Smad4 pathway, wherein, Par-4 induction/over-expression induced EMT which was later culminated in to apoptosis in presence of TGF-β via positive regulation of Smad4. Intriguingly, Par-4^-/- cells were devoid of significant Smad4 induction compared to Par-4^+/+ cells in presence of TGF-β and ectopic Par-4 steadily augmented Smad4 expression by restoring TGF-β/Smad4 axis in Panc-1 cells. Further, our FACS and western blotting results unveiled that Par-4 dragged the PDAC cells to G₁ arrest in presence of TGF-β byelevating p21 and p27 levels while attenuating Cyclin E and A levels and augmenting caspase 3 cleavage triggering lethal EMT. Through restoration of Smad4, we further establish that in BxPC3 cell line (Smad4^-/-), Smad4 is essential for Par-4 to indulge TGF-β dependent lethal EMT program. The mechanistic relevance of Par-4 mediated Smad4 activation was additionally validated by co-immunoprecipitation wherein disruption of NM23H1-STRAP interaction by Par-4 rescues TGF-β/Smad4 pathway in PDAC and mediates the tumor suppressive role of TGF-β, therefore serving as a vital cog to restore the apoptotic functions of TGF-β pathway.

Differential migration-related gene expression and altered cytokine secretion in response to serum starvation in cultured MDA-MB-231 cells

Background

Serum starvation is mostly considered as a standard preparatory method in many cellular and molecular experiments. However, recent studies give some evidence that serum starvation is a major event that triggers various cell responses and has therefore great potential to change and interfere with the experimental results. In this study, the behavior of breast cancer cells in serum-starved condition was examined.

Objective

To focus on the role of serum starvation on cell migration and also the possible changes in the expression and secretion of genes and cytokines mostly involved in migration and chemotaxis of breast cancer cells.

Methods

MDA-MB-231 cells were cultured under serum-starved condition. Transwell migration assay was performed to evaluate the effect of serum starvation on cell migration after 24, 48, and 72 h. The transcriptional expression of migration-related genes was evaluated using real-time polymerase chain reaction. The cytokine secretion was also analyzed using enzyme-linked immunosorbent assay.

Results

Serum starvation suppressed cell migration in breast cancer cells. Additionally, the gene expression of markers involved in migration including β-catenin, twist, zinc finger E-box binding homeobox 1, vimentin, fibronectin, intercellular adhesion molecule 1, and vascular endothelial growth factor were downregulated. Moreover, cytokines of transforming growth factor, beta 1, matrix metallopeptidase 9, interleukin 8, and nitric oxide were differentially secreted.

Conclusions

Serum deprivation causes significant changes in cancer cell migration and also the expression of migration-related genes and cytokines, special care needs to be taken when this practice is used as preparatory method especially in migration and chemotaxis experiments on cancer cells.

Vimentin activation in early apoptotic cancer cells errands survival pathways during DNA damage inducer CPT treatment in colon carcinoma model

Epithelial to mesenchymal transitions (EMT) is a preparatory process for cancer cells to attain motility and further metastasis to distant sites. Majority of DNA damaging drugs have shown to develop EMT as one of the major mechanisms to attain drug resistance. Here we sought to understand the resistance/survival instincts of cancer cells during initial phase of drug treatment. We provide a tangible evidence of stimulation of EMT factors in Apc knockout colorectal carcinoma model. Our results implied that CPT-treated Apc knockout cohorts depicted increased pro-invasive and pro-survival factors (Vimentin/p^ser38Vimentin & NFκB). Moreover, by cell sorting experiment, we have observed the expression of Vimentin in early apoptotic cells (AnnexinV positive) from 36 to 48 h of CPT treatment. We also observed the expression of chimeric Sec-AnnexinV-mvenus protein in migrated cells on transwell membrane recapitulating signatures of early apoptosis. Notably, induction of Vimentin-mediated signaling (by CPT) delayed apoptosis progression in cells conferring survival responses by modulating the promoter activity of NFκB. Furthermore, our results unveiled a novel link between Vimentin and ATM signaling, orchestrated via binding interaction between Vimentin and ATM kinase. Finally, we observed a significant alteration of crypt-villus morphology upon combination of DIM (EMT inhibitor) with CPT nullified the background EMT signals thus improving the efficacy of the DNA damaging agent. Thus, our findings revealed a resistance strategy of cancer cells within a very initial period of drug treatment by activating EMT program, which hinders the cancer cells to achieve later phases of apoptosis thus increasing the chances of early migration.

Role of PARK7 and NDKA in stroke management: a review of PARK7 and NDKA as stroke biomarkers

AIM

Biomarkers are molecules measured in plasma, serum or other body fluids to characterize a disease. PARK7 and NDKA roles in the management of stroke are still on study. Therefore, their potentials need to be developed in totality. The aim of this review is to demonstrate that PARK7 and NDKA could present more clinical important information as biomarkers for management of stroke disease. Main contents: Four main aspects of PARK7 and NDKA are exploited in this review. First, their diagnostic value is discussed in order to demonstrate their possible role as stroke diagnosis markers. Second, this article will exploit the correlation of both markers with time, by showing their dynamic changes in serum and plasma. Third, it describes the observed relationship of their levels with NIH Stroke Scale. The last aspect visits the possibility of their implementation in stroke therapy.

CONCLUSION

This article explores recent findings and proposes the potential roles that PARK7 and NDKA play in the management of acute stroke disease.

Potential role of nucleoside diphosphate kinase in myricetin-induced selective apoptosis in colon cancer HCT-15 cells

The flavonoid myricetin (MYR) is derived from vegetables and fruits. It has been shown to exert anti-cancer effects in various cell lines; however, the exact mechanism underlying these effects is yet to be elucidated. In this study, we evaluated the anti-cancer effects induced by MYR treatment in colon cancer HCT-15 cells. To detect cell proliferation, we conducted MTT assay and real time-cell electronic sensing (RT-CES). We next performed comet assay and Annexin V and PI staining to detect cellular apoptotic features. After that, we conducted two-dimensional electrophoresis (2-DE) analysis to identify apoptotic proteins. The results of this analysis revealed that eight spots were differentially expressed. Among the spots, we selected nucleoside diphosphate kinase (NDPK) for further investigation, as it has been shown to regulate cancer cell apoptosis and metastasis. After that, we conducted realtime-PCR and western blot to detect the expression of NDPK mRNA and protein and wound-healing assay to detect cell migration and invasion. Finally, we performed NDPK siRNA transfection study and the results showed that NDPK knockdown inhibited apoptosis. Based on these collective results, we suggest that MYR induces apoptosis in human colon cancer HCT-15 cells selectively by increasing the expression of NDPK and other caspase-regulated apoptosis proteins.

Regiospecific Synthesis of Ring A Fused Withaferin A Isoxazoline Analogues: Induction of Premature Senescence by W-2b in Proliferating Cancer Cells

Induction of premature senescence represents a novel functional strategy to curb the uncontrolled proliferation of malignant cancer cells. This study unveils the regiospecific synthesis of novel isoxazoline derivatives condensed to ring A of medicinal plant product Withaferin-A. Intriguingly, the cis fused products with β-oriented hydrogen exhibited excellent cytotoxic activities against proliferating human breast cancer MCF7 and colorectal cancer HCT-116 cells. The most potent derivative W-2b triggered premature senescence along with increase in senescence-associated β-galactosidase activity, G2/M cell cycle arrest, and induction of senescence-specific marker p21^Waf1/Cip1 at its sub-toxic concentration. W-2b conferred a robust increase in phosphorylation of mammalian checkpoint kinase-2 (Chk2) in cancer cells in a dose-dependent manner. Silencing of endogenous Chk2 by siRNA divulged that the amplification of p21 expression and senescence by W-2b was Chk2-dependent. Chk2 activation (either by ectopic overexpression or through treatment with W-2b) suppressed NM23-H1 signaling axis involved in cancer cell proliferation. Finally, W-2b showed excellent in vivo efficacy with 83.8% inhibition of tumor growth at a dose of 25 mg/kg, b.w. in mouse mammary carcinoma model. Our study claims that W-2b could be a potential candidate to limit aberrant cellular proliferation rendering promising improvement in the treatment regime in cancer patients.