TFF1 activates p53 through down-regulation of miR-504 in gastric cancer

MicroRNA-34 and gastrointestinal cancers: a player with big functions

It is commonly assumed that gastrointestinal cancer is the most common form of cancer across the globe and is the leading contributor to cancer-related death. The intricate mechanisms underlying the growth of GI cancers have been identified. It is worth mentioning that both non-coding RNAs (ncRNAs) and certain types of RNA, such as circular RNAs (circRNAs), long non-coding RNAs (lncRNAs), and microRNAs (miRNAs), can have considerable impact on the development of gastrointestinal (GI) cancers. As a tumour suppressor, in the group of short non-coding regulatory RNAs is miR-34a. miR-34a silences multiple proto-oncogenes at the post-transcriptional stage by targeting them, which inhibits all physiologically relevant cell proliferation pathways. However, it has been discovered that deregulation of miR-34a plays important roles in the growth of tumors and the development of cancer, including invasion, metastasis, and the tumor-associated epithelial-mesenchymal transition (EMT). Further understanding of miR-34a's molecular pathways in cancer is also necessary for the development of precise diagnoses and effective treatments. We outlined the most recent research on miR-34a functions in GI cancers in this review. Additionally, we emphasize the significance of exosomal miR-34 in gastrointestinal cancers.

Trefoil Family Factor Peptide 1-A New Biomarker in Liquid Biopsies of Retinoblastoma under Therapy

Effective management of retinoblastoma (RB), the most prevalent childhood eye cancer, depends on reliable monitoring and diagnosis. A promising candidate in this context is the secreted trefoil family factor peptide 1 (TFF1), recently discovered as a promising new biomarker in patients with a more advanced subtype of retinoblastoma. The present study investigated TFF1 expression within aqueous humor (AH) of enucleated eyes and compared TFF1 levels in AH and corresponding blood serum samples from RB patients undergoing intravitreal chemotherapy (IVC). TFF1 was consistently detectable in AH, confirming its potential as a biomarker. Crucially, our data confirmed that TFF1-secreting cells within the tumor mass originate from RB tumor cells, not from surrounding stromal cells. IVC-therapy-responsive patients exhibited remarkably reduced TFF1 levels post-therapy. By contrast, RB patients' blood serum displayed low-to-undetectable levels of TFF1 even after sample concentration and no therapy-dependent changes were observed. Our findings suggest that compared with blood serum, AH represents the more reliable source of TFF1 if used for liquid biopsy RB marker analysis in RB patients. Thus, analysis of TFF1 in AH of RB patients potentially provides a minimally invasive tool for monitoring RB therapy efficacy, suggesting its importance for effective treatment regimens.

C/EBPα Epigenetically Modulates TFF1 Expression via mC-6 Methylation in the Jejunum Inflammation Induced by a Porcine Coronavirus

Porcine epidemic diarrhea virus (PEDV) is an emerging coronavirus which causes acute diarrhea and destroys gastrointestinal barrier function in neonatal pigs. Trefoil factor 1 (TFF1) is a protective peptide for maintaining the integrity of gastrointestinal mucosa and reducing intestinal inflammation. However, its role in protecting intestinal epithelium against PEDV infection is still unclear. In this study, we discovered that TFF1 expression was activated in the jejunum of pigs with PEDV infection and TFF1 is required for the growth of porcine intestinal epithelial cells. For instance, inhibited cell proliferation and cell arrest were observed when TFF1 is genetically knocked-out using CRISPR-Cas9. Additionally, TFF1 depletion increased viral copy number and PEDV titer, along with the elevated genes involved in antiviral and inflammatory cytokines. The decreased TFF1 mRNA expression is in line with hypermethylation on the gene promoter. Notably, the strong interactions of protein-DNA complexes containing CCAAT motif significantly increased C/EBPα accessibility, whereas hypermethylation of mC-6 loci decreased C/EBPα binding occupancies in TFF1 promoter. Overall, our findings show that PEDV triggers the C/EBPα-mediated epigenetic regulation of TFF1 in intestine epithelium and facilitates host resistance to PEDV and other Coronavirus infections.

Endoplasmic Reticulum Stress and Impairment of Ribosome Biogenesis Mediate the Apoptosis Induced by Ocimum x africanum Essential Oil in a Human Gastric Cancer Cell Line

Background and Objectives: Gastric cancer remains a major unmet clinical problem worldwide. Although conventional medical treatments are available, their curative effects are generally unsatisfactory. Consequently, it remains necessary to search natural products for potential alternatives in treating gastric cancer patients. Ocimum x africanum Lour. is a culinary herb that has been used in folk medicine for various diseases, but little is known regarding its anti-cancer activity against gastric cancer cells. In the current study, we focus on the anti-cancer mechanisms of O. x africanum essential oil (OAEO) in the AGS human gastric cancer cell line. Materials and Methods: After OAEO treatment, AGS cell viability was evaluated by MTT assay. Cell migration and apoptotic nuclear morphology were determined by wound-healing assay and DAPI staining, respectively. Gene expression levels of apoptosis-related genes were quantified by qRT–PCR. Differential protein expression was determined with an LC–MS/MS-based proteomics approach to identify the key proteins that may be important in the anti-cancer mechanisms of OAEO on AGS cells. The chemical constituents of OAEO were identified by GC–MS analysis. Results: We found OAEO to exhibit a potent growth-inhibiting effect on AGS cells, with an IC₅₀ value of 42.73 µg/mL. After OAEO treatment for 24 h, AGS cell migration was significantly decreased relative to the untreated control. OAEO-treated AGS cells exhibited common features of apoptotic cell death, including cell shrinkage, membrane blebbing, chromatin condensation, and nuclear fragmentation. Apoptotic cell death was confirmed by qRT–PCR for apoptosis-related genes, revealing that OAEO decreased the expression of anti-apoptotic genes (BCL2 and BCL-xL) and activated pro-apoptotic genes and apoptotic caspase genes (TP53, BAX, CASP9, CASP12, and CASP3). Moreover, expression of CASP8 was not changed after treatment. Proteomic analysis revealed that OAEO may produce a signature effect on protein clusters relating to unfolded protein accumulation, thereby inducing severe ER stress and also impairing ribosome synthesis. STRING analysis revealed seven up-regulated and 11 down-regulated proteins, which were significantly associated with protein folding and ribosome biogenesis, respectively. Using GC–MS analysis, 6-methyl-5-hepten-2-one, citral, neral, and linalool were found to be the major chemical constituents in OAEO. Conclusions: Taken together, these results indicate that OAEO has a potential anti-proliferative effect on AGS cells. Our molecular findings show evidence supporting an important role of ER stress and ribosome biogenesis impairment in mediating the induction of cell death by OAEO through the mitochondrial-apoptotic pathway. This study, therefore, provides fundamental knowledge for future applications using OAEO as an alternative therapy in gastric cancer management.

TFF-1 Functions to Suppress Multiple Phenotypes Associated with Lung Cancer Progression

Introduction

Trefoil Factor (TFF) is a member of a protein family comprised of three isoforms, of which TFF-1 exhibits antithetical functions; promotion or suppression of cell proliferation, survival and invasion, depending on the cancer type. However, the pathobiological function of TFF-1 in lung carcinoma has been still unclear.

Methods

We examined the expression and secretion of TFF-1 using cultured human lung carcinoma cells by immunoblotting, immunofluorescence, enzyme-linked immunosorbent assay and quantitative real-time PCR analyses. The effects of TFF-1 on various phenotypes were analyzed in two cell lines, including those transfected with cDNA encoding TFF-1. Cell proliferation and death were examined by hemocytometer cell counting and by colorimetric viability/cytotoxicity assay. Cell cycle profile, migration and invasion were also examined by flow cytometry, wound healing assay and Matrigel Transwell assay, respectively. The effect of TFF-1 overexpression was confirmed by additional transfection of TFF-1-specific siRNA.

Results

Endogenous TFF-1 protein expression and secretion into the media were observed exclusively in adenocarcinoma-derived cell lines. Forced overexpression of TFF-1 drove cell cycle transition, while the proliferation decreased by 19% to 25% due to increased cell death. This cell death was predominantly caused by apoptosis, as assessed by the activation of caspase 3/7. Cell migration was also suppressed by 71% to 82% in TFF-1-transfected cells. The suppressive effect of TFF-1 on proliferation and migration was restored by transfection of TFF-1 siRNA. Moreover, invasion was also suppressed to 77% to 83% in TFF-1-transfected cells.

Conclusion

These findings reveal that TFF-1 functions as a suppressor of cancer proliferation by induction of apoptosis, cell migration and invasion and thus may provide a synergistic target for potential treatment strategies for human lung carcinoma.

NF-kB-dependent activation of STAT3 by H. pylori is suppressed by TFF1

BACKGROUND

H. pylori infection is the main risk factor for gastric cancer. In this study, we investigated H. pylori-mediated activation of STAT3 and NF-κB in gastric cancer, using in vitro and in vivo models.

METHODS

To investigate the activation of NF-κB and STAT3 by H. pylori strains we used in vitro and in vivo mouse models, western blots, immunofluorescence, ChIP Assay, luciferase and quantitative real-time PCR assays.

RESULTS

Following infection with H. pylori in vitro, we found an earlier phosphorylation of NF-kB-p65 (S536), followed by STAT3 (Y705). Immunofluorescence, using in vitro and in vivo models, demonstrated nuclear localization of NF-kB and STAT3, following H. pylori infection. NF-kB and STAT3 luciferase reporter assays confirmed earlier activation of NF-kB followed by STAT3. In vitro and in vivo models demonstrated induction of mRNA expression of IL-6 (p < 0.001), VEGF-α (p < 0.05), IL-17 (p < 0.001), and IL-23 (p < 0.001). Using ChIP, we confirmed co-binding of both NF-kB-p65 and STAT3 on the IL6 promoter. The reconstitution of Trefoil Factor 1 (TFF1) suppressed activation of NF-kB with reduction in IL6 levels and STAT3 activity, in response to H. pylori infection. Using pharmacologic (BAY11-7082) and genetic (IκB super repressor (IκBSR)) inhibitors of NF-kB-p65, we confirmed the requirement of NF-kB-p65 for activation of STAT3, as measured by phosphorylation, transcription activity, and nuclear localization of STAT3 in in vitro and in vivo models.

CONCLUSION

Our findings suggest the presence of an early autocrine NF-kB-dependent activation of STAT3 in response to H. pylori infection. TFF1 acts as an anti-inflammatory guard against H. pylori-mediated activation of pro-inflammatory networks.

An In Vitro Anti-Cancer Activity of Ocimum tenuiflorum Essential Oil by Inducing Apoptosis in Human Gastric Cancer Cell Line

Background and Objectives: The effects of Ocimum tenuiflorum essential oil (OTEO) against gastric cancer remain unknown and merit investigation. Materials and Methods: In the present study, the anti-cancer activity of OTEO was examined in a human gastric cancer cell line (AGS). After OTEO treatment, AGS cell viability was determined by an MTT assay, and inhibition of metastasis was determined by cell migration and invasion assays. The expression of apoptosis-related genes in treated AGS cells was determined by qRT-PCR. Results: OTEO significantly decreased AGS cell viability in a dose-dependent manner (IC₅₀ 163.42 µg/mL) and effectively inhibited cell migration and invasion. Morphological examination demonstrated that OTEO induced cell shrinkage, chromatin condensation, and fragmentation, which are considered typical morphologies of apoptotic cell death. Pro-apoptotic genes (TP53, BAX, and BAK) were significantly up-regulated, while anti-apoptotic genes (BCL-2 and BCL-xL) were significantly down-regulated after treatment with OTEO. In addition, significantly increased gene expression was detected for CASP8, CASP9, and CASP3 in AGS cells exposed to OTEO. GC-MS analysis demonstrated that the major compound of OTEO was caryophyllene (25.85%) and α-pinene (11.66%). Conclusions: This in vitro study demonstrates for the first time that OTEO has potential anti-gastric cancer activity and may induce apoptosis in AGS cells through extrinsic and intrinsic pathways.

miR-504 Promoted Gastric Cancer Cell Proliferation and Inhibited Cell Apoptosis by Targeting RBM4

Background

The purpose of this study was to explore the role and underlying mechanism of miR-504 and RBM4 in gastric cancer.

Methods

The qRT-PCR or Western blot was performed to determine the expressions of miR-504 and RBM4 in the gastric cancer tissues and normal tissues. Human SGC-7901 cells were transfected with miR-504 mimic/inhibitor or pcDNA-RBM4. Cell proliferation and cell apoptosis were assessed by colony formation assay and flow cytometry, respectively. Luciferase reporter gene assays were used to investigate interactions between miR-504 and RBM4 in SGC-7901 cells.

Results

The relative expression of miR-504 was significantly upregulated in the gastric cancer group (n = 25) than in the paired normal group (n = 25), but the relative RBM4 expression was remarkably downregulated in the gastric tumor group, compared with the normal group. Additionally, miR-504 overexpression increased the viability of gastric cancer cells. Moreover, RBM4 is a functional target of miR-504 in gastric cancer cells. miR-504 was further confirmed to promote SGC-7901 cell proliferation and inhibit cell apoptosis by downregulation RBM4 in vitro.

Conclusions

miR-504 promotes gastric cancer cell proliferation and inhibits cell apoptosis by targeting RBM4, and this provides a potential diagnostic biomarker and treatment for patients with gastric cancer.

RNA sequencing of long-term label-retaining colon cancer stem cells identifies novel regulators of quiescence

Recent data suggest that therapy-resistant quiescent cancer stem cells (qCSCs) are the source of relapse in colon cancer. Here, using colon cancer patient-derived organoids and xenografts, we identify rare long-term label-retaining qCSCs that can re-enter the cell cycle to generate new tumors. RNA sequencing analyses demonstrated that these cells display the molecular hallmarks of quiescent tissue stem cells, including expression of p53 signaling genes, and are enriched for transcripts common to damage-induced quiescent revival stem cells of the regenerating intestine. In addition, we identify negative regulators of cell cycle, downstream of p53, that we show are indicators of poor prognosis and may be targeted for qCSC abolition in both p53 wild-type and mutant tumors. These data support the temporal inhibition of downstream targets of p53 signaling, in combination with standard-of-care treatments, for the elimination of qCSCs and prevention of relapse in colon cancer.

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Colon tumors contain therapy-resistant quiescent cancer stem cells (qCSCs)

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qCSC gene expression mirrors that of quiescent stem cells of the regenerating gut

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qCSCs are enriched for p53 signaling genes

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qCSC elimination may be achieved by inhibiting downstream targets of p53 signaling

Zinc Gluconate Induces Potentially Cancer Chemopreventive Activity in Barrett's Esophagus: A Phase 1 Pilot Study

BACKGROUND

Chemopreventive effects of zinc for esophageal cancer have been well documented in animal models. This prospective study explores if a similar, potentially chemopreventive action can be seen in Barrett's esophagus (BE) in humans.

AIMS

To determine if molecular evidence can be obtained potentially indicating zinc's chemopreventive action in Barrett's metaplasia.

METHODS

Patients with a prior BE diagnosis were placed on oral zinc gluconate (14 days of 26.4 mg zinc BID) or a sodium gluconate placebo, prior to their surveillance endoscopy procedure. Biopsies of Barrett's mucosa were then obtained for miRNA and mRNA microarrays, or protein analyses.

RESULTS

Zinc-induced mRNA changes were observed for a large number of transcripts. These included downregulation of transcripts encoding proinflammatory proteins (IL32, IL1β, IL15, IL7R, IL2R, IL15R, IL3R), upregulation of anti-inflammatory mediators (IL1RA), downregulation of transcripts mediating epithelial-to-mesenchymal transition (EMT) (LIF, MYB, LYN, MTA1, SRC, SNAIL1, and TWIST1), and upregulation of transcripts that oppose EMT (BMP7, MTSS1, TRIB3, GRHL1). miRNA arrays showed significant upregulation of seven miRs with tumor suppressor activity (-125b-5P, -132-3P, -548z, -551a, -504, -518, and -34a-5P). Of proteins analyzed by Western blot, increased expression of the pro-apoptotic protein, BAX, and the tight junctional protein, CLAUDIN-7, along with decreased expression of BCL-2 and VEGF-R2 were noteworthy.

CONCLUSIONS

When these mRNA, miRNA, and protein molecular data are considered collectively, a cancer chemopreventive action by zinc in Barrett's metaplasia may be possible for this precancerous esophageal tissue. These results and the extensive prior animal model studies argue for a future prospective clinical trial for this safe, easily-administered, and inexpensive micronutrient, that could determine if a chemopreventive action truly exists.

RNA-Seq Analysis of Cisplatin and the Monofunctional Platinum(II) Complex, Phenanthriplatin, in A549 Non-Small Cell Lung Cancer and IMR90 Lung Fibroblast Cell Lines

Phenanthriplatin is a new monofunctional platinum(II) complex that binds only one strand of DNA and acts by blocking gene transcription, but its effect on gene regulation has not been characterized relative to the traditional platinum-based complex, cisplatin. A549 non-small cell lung cancer and IMR90 lung fibroblast cells were treated with cisplatin, phenanthriplatin, or a control and then their RNA transcripts were subjected to next generation sequencing analysis. DESeq2 and CuffDiff2 were used to identify up- and downregulated genes and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases were used to identify pathways and functions. We found that phenanthriplatin may regulate the genes GPRC5a, TFF1, and TNFRSF10D, which act through p53 to control apoptosis, differently or to a greater extent than cisplatin, and that it, unlike cisplatin, could upregulate ATP5MD, a gene which signals through the Wnt/β catenin pathway. Furthermore, phenanthriplatin caused unique or enhanced effects compared to cisplatin on genes regulating the cytoskeleton, cell migration, and proliferation, e.g., AGAP1, DIAPH2, GDF15, and THSD1 (p < 0.05; q < 0.05). Phenanthriplatin may modulate some oncogenes differently than cisplatin potentially leading to improved clinical outcome, but this monofunctional complex should be carefully matched with cancer gene data to be successfully applied in chemotherapy.

Bladder cancer-associated transcript 2 contributes to nephroblastoma progression

BACKGROUND

Nephroblastoma is a common pediatric kidney tumor. Existing evidence has indicated that long non-coding RNAs (lncRNAs) may be associated with tumorigenesis such as nephroblastoma. However, the contribution of lncRNA bladder cancer-associated transcript 2 (BLACAT2) to tumorigenesis and postoperative nephroblastoma prognosis remains unknown.

METHODS

A total of 50 pairs of patient nephroblastoma and corresponding adjacent non-tumorous tissues were analyzed for BLACAT2 expression. The underlying roles of BLACAT2 in nephroblastoma cells were also investigated. BLACAT2 level was detected in four nephroblastoma cell lines and normal cell line NGC-407 using quantitative real-time PCR. The potential influence of BLACAT2 on nephroblastoma cells was explored based on RNA interference technology in vitro and in vivo. Moreover, the miRNA targeted by BLACAT2 and its target gene were predicted and verified.

RESULTS

BLACAT2 silencing suppressed cell proliferation, colony formation, and tumor growth in vivo and promoted cell apoptosis in vitro. Furthermore, BLACAT2 could directly bind to miR-504-3p, thereby decreasing miR-504-3p expression. In addition, the impact of miR-504-3p on proliferation, colony formation, and nephroblastoma cell apoptosis was reversed by BLACAT2. Wnt11 was identified as a target of miR-504-3p.

CONCLUSIONS

Our study revealed that a novel BLACAT2/miR-504-3p/Wnt11 axis is associated with nephroblastoma, where BLACAT2 is able to sponge miR-504-3p to down-regulate Wnt11.

miR-504 modulates the stemness and mesenchymal transition of glioma stem cells and their interaction with microglia via delivery by extracellular vesicles

Glioblastoma (GBM) is a highly aggressive tumor with poor prognosis. A small subpopulation of glioma stem cells (GSCs) has been implicated in radiation resistance and tumor recurrence. In this study we analyzed the expression of miRNAs associated with the functions of GSCs using miRNA microarray analysis of these cells compared with human neural stem cells. These analyses identified gene clusters associated with glioma cell invasiveness, axonal guidance, and TGF-β signaling. miR-504 was significantly downregulated in GSCs compared with NSCs, its expression was lower in GBM compared with normal brain specimens and further decreased in the mesenchymal glioma subtype. Overexpression of miR-504 in GSCs inhibited their self-renewal, migration and the expression of mesenchymal markers. The inhibitory effect of miR-504 was mediated by targeting Grb10 expression which acts as an oncogene in GSCs and GBM. Overexpression of exogenous miR-504 resulted also in its delivery to cocultured microglia by GSC-secreted extracellular vesicles (EVs) and in the abrogation of the GSC-induced polarization of microglia to M2 subtype. Finally, miR-504 overexpression prolonged the survival of mice harboring GSC-derived xenografts and decreased tumor growth. In summary, we identified miRNAs and potential target networks that play a role in the stemness and mesenchymal transition of GSCs and the miR-504/Grb10 pathway as an important regulator of this process. Overexpression of miR-504 exerted antitumor effects in GSCs as well as bystander effects on the polarization of microglia via delivery by EVs.

Odyssey of trefoil factors in cancer: Diagnostic and therapeutic implications

Trefoil factors 1, 2, and 3 (TFFs) are a family of small secretory molecules involved in the protection and repair of the gastrointestinal tract (GI). TFFs maintain and restore epithelial structural integrity via transducing key signaling pathways for epithelial cell migration, proliferation, and invasion. In recent years, TFFs have emerged as key players in the pathogenesis of multiple diseases, especially cancer. Initially recognized as tumor suppressors, emerging evidence demonstrates their key role in tumor progression and metastasis, extending their actions beyond protection. However, to date, a comprehensive understanding of TFFs' mechanism of action in tumor initiation, progression and metastasis remains obscure. The present review discusses the structural, functional and mechanistic implications of all three TFF family members in tumor progression and metastasis. Also, we have garnered information from studies on their structure and expression status in different organs, along with lessons from their specific knockout in mouse models. In addition, we highlight the emerging potential of using TFFs as a biomarker to stratify tumors for better therapeutic intervention.

miR-103 promotes hepatocellular carcinoma cell proliferation and migration in the simulation transition zone of RFA through PI3K/Akt signaling pathway by targeting PTEN

Radiofrequency ablation (RFA) is a potentially curative therapy for nontransplantable hepatocellular carcinoma (HCC). However, as tumor size increases, incomplete RFA can increase rates of local recurrence and tumor progression. As such, there remains a need to identify potential biologic mechanisms mediating HCC response to thermal ablation. Our results revealed that miR-103 was markedly upregulated in recurrent HCC tissues treated with RFA as first-line treatment and in HCC lines after heat stress in vitro, simulating the marginal zone of RFA treatment. Gain-of-function and loss-of-function studies showed that miR-103 ectopic overexpression promoted, but miR-103 silencing reduced, heat-exposed HCC proliferation, and migration in vitro. Western blotting displayed that proteins related with proliferation and migration were significantly changed in different groups. Furthermore, PTEN may be a potential target of miR-103 and miR-103 could activate the PI3K/Akt pathway by suppressing PTEN expression. Taken together, these studies provide experimental evidence supporting a role for miR-103 in HCC response to heat stress.

High-throughput sequencing reveals biofluid exosomal miRNAs associated with immunity in pigs

Large numbers of miRNAs are found in biofluid exosomes. We isolated ~50-200 nm diameter exosomes from four types of porcine biofluid (urine, plasma, semen, and bile) using serial centrifugation and ultracentrifugation procedures. A total of 42.15 M raw data were generated from four small RNA libraries. This produced 40.17 M map-able sequences, of which we identified 204 conserved miRNAs, and 190 novel candidate miRNAs. Furthermore, we identified 34 miRNAs specifically expressed in only one library, all with well-characterized immune-related functions. A set of five universally abundant miRNAs (miR-148a-3p, miR-21-5p, let-7f-5p, let-7i-5p, and miR-99a-5p) across all four biofluids was also found. Function enrichment analysis revealed that the target genes of the five ubiquitous miRNAs are primarily involved in immune and RNA metabolic processes. In summary, our findings suggest that porcine biofluid exosomes contain a large number of miRNAs, many of which may be crucial regulators of the immune system.

p53, miR-34a and EMP1-Newly Identified Targets of TFF3 Signaling in Y79 Retinoblastoma Cells

Trefoil factor family peptide 3 (TFF3) is supposed to have tumor suppressive functions in retinoblastoma (RB), but the functional pathway is not completely understood. In the study presented, we investigated the downstream pathway of TFF3 signaling in Y79 RB cells. Results from pG13-luciferase reporter assays and western blot analyses indicate induced p53 activity with an upregulation of miR-34a after TFF3 overexpression. Expression levels of the predicted miR-34a target epithelial membrane protein 1 (EMP1) are reduced after TFF3 overexpression. As revealed by WST-1 assay, BrdU, and DAPI cell counts viability and proliferation of Y79 cells significantly decrease following EMP1 knockdown, while apoptosis levels significantly increase. Opposite effects on Y79 cells’ growth could be shown after EMP1 overexpression. Caspase assays showed that EMP1 induced apoptosis after overexpression is at least partially caspase-3/7 dependent. Colony formation and soft agarose assays, testing for anchorage independent growth, revealed that EMP1 overexpressing Y79 cells have a significantly higher ability to form colonies. In in ovo chicken chorioallantoic membrane (CAM) assays inoculated EMP1 overexpressing Y79 cells form significantly larger CAM tumors. Moreover, miR-34a overexpression increases sensitivity of Y79 cells towards RB chemotherapeutics, however, without involvement of EMP1. In summary, the TFF3 signaling pathway in Y79 RB cells involves the activation of p53 with downstream induction of miR-34a and subsequent inhibition of EMP1.

Activation of STAT3 signaling is mediated by TFF1 silencing in gastric neoplasia

TFF1, a secreted protein, plays an essential role in keeping the integrity of gastric mucosa and its barrier function. Loss of TFF1 expression in the TFF1-knockout (KO) mouse leads to a pro-inflammatory phenotype with a cascade of gastric lesions that include low-grade dysplasia, high-grade dysplasia, and adenocarcinomas. In this study, we demonstrate nuclear localization of p-STAT^Y705, with significant overexpression of several STAT3 target genes in gastric glands from the TFF1-KO mice. We also show frequent loss of TFF1 with nuclear localization of STAT3 in human gastric cancers. The reconstitution of TFF1 protein in human gastric cancer cells and 3D gastric glands organoids from TFF1-KO mice abrogates IL6-induced nuclear p-STAT3^Y705 expression. Reconstitution of TFF1 inhibits IL6-induced STAT3 transcription activity, suppressing expression of its target genes. TFF1 blocks IL6Rα-GP130 complex formation through interfering with binding of IL6 to its receptor IL6Rα. These findings demonstrate a functional role of TFF1 in suppressing gastric tumorigenesis by impeding the IL6-STAT3 pro-inflammatory signaling axis.

Trefoil factor 1 (TFF1) is a protein secreted by the gastric mucosa that protects against gastric tumourigenesis. Here, the authors show that TFF1 inhibits the oncogenic inflammatory response and IL-6-mediated STAT3 activation by interfering with the binding of IL6 to its receptor IL6Rα.

miR-150-504-519d inhibits the growth of human colorectal cancer cell line SW48 and downregulates c-FLIP receptor

microRNAs (miRNAs) are noncoding RNAs that regulates the expression of target messenger RNAs (mRNAs). c-FLIP is an inhibitor of cell apoptosis through inhibition of caspase 8. miR-150, miR-504, and miR-519d were related to cancer cell proliferation, invasion, and migration in colorectal cancer (CRC). However, the role of miR-150-504-519d in CRC has not been studied and the relationship between miR-150-504-519d and c-FLIP remains unclear. In this study, we found that c-FLIP was upregulated in CRC tissues, without detectable expression in normal CRC tissues. Using SW48 cell line, we further showed that miR-150-504-519d inhibited migration, invasion, and promoted apoptosis of SW48 cells. Moreover, in SW48 cell line transfected with miR-150-504-519d, the protein expression of c-FLIP was significantly lower compared with cells transfected with scramble. Our results demonstrated upregulation of c-FLIP in CRC, which was downregulated in SW48 cells after the transfection of miR-150-504-519d, suggesting that manipulation of miR-150-504-519d expression might be a novel approach for the treatment of colorectal cancer.

Review: Precision medicine and driver mutations: Computational methods, functional assays and conformational principles for interpreting cancer drivers

At the root of the so-called precision medicine or precision oncology, which is our focus here, is the hypothesis that cancer treatment would be considerably better if therapies were guided by a tumor’s genomic alterations. This hypothesis has sparked major initiatives focusing on whole-genome and/or exome sequencing, creation of large databases, and developing tools for their statistical analyses—all aspiring to identify actionable alterations, and thus molecular targets, in a patient. At the center of the massive amount of collected sequence data is their interpretations that largely rest on statistical analysis and phenotypic observations. Statistics is vital, because it guides identification of cancer-driving alterations. However, statistics of mutations do not identify a change in protein conformation; therefore, it may not define sufficiently accurate actionable mutations, neglecting those that are rare. Among the many thematic overviews of precision oncology, this review innovates by further comprehensively including precision pharmacology, and within this framework, articulating its protein structural landscape and consequences to cellular signaling pathways. It provides the underlying physicochemical basis, thereby also opening the door to a broader community.

MicroRNA‑504 targets AEG‑1 and inhibits cell proliferation and invasion in retinoblastoma

The dysregulation of microRNAs (miRNAs/miRs) has become increasingly recognized as a primary feature of retinoblastoma (RB). Furthermore, miRNAs have been demonstrated to be involved in the occurrence and development of RB. Therefore, it is crucial to investigate the expression profile and roles of miRNAs in RB in order to identify potential therapeutic targets to treat patients with RB. The expression profile and biological roles of miRNA‑504 (miR‑504) have been reported in numerous types of human cancer; however, the roles of miR‑504 in RB remain unknown. In the present study, it was demonstrated that miR‑504 expression was significantly decreased in RB tissues and cell lines. Functional analysis identified that resumption of miR‑504 expression suppressed cell proliferation and invasion in RB. Furthermore, astrocyte elevated gene‑1 (AEG‑1) was determined to be a direct target of miR‑504 in RB, and a negative correlation between miR‑504 and AEG‑1 mRNA expression levels was observed in RB tissues. Additionally, the tumor‑suppressing effects of miR‑504 overexpression in RB cells could be rescued by AEG‑1 upregulation. In conclusion, these results indicated a significant role of the miR‑504/AEG‑1 pathway in inhibiting the aggressiveness of RB, suggesting that this miRNA may be employed as a therapeutic target for the treatment of patients with this disease.

MicroRNA-504 modulates osteosarcoma cell chemoresistance to cisplatin by targeting p53

Chemoresistance implicates the therapeutic value of cisplatin and remains a primary obstacle to its clinical use. MicroRNAs (miRs) negatively modulate the expression of their target genes and are associated with the occurrence and progression of various types of tumor. The abnormal expression of miR-504 has been reported in certain types of human tumor and has been associated with tumor prognosis. However, the association between miR-504 and cisplatin in human osteosarcoma remains unclear. The present study therefore aimed to assess the in vitro effects and possible mechanism of miR-504 in cell proliferation, apoptosis and cisplatin resistance in MG63 osteosarcoma cells. The results demonstrated that miR-504 was overexpressed in osteosarcoma tissues and cells. This overexpression also induced cell proliferation, as determined by MTT and EdU staining assays. Furthermore, miR-504 suppressed cisplatin-induced apoptosis, which was demonstrated via MTT, cell morphology analysis and flow cytometry. Cisplatin-induced G₁ arrest was also suppressed, which was determined by flow cytometry. The potential target genes of miR-504 were predicted using bioinformatics. p53 was confirmed to be a direct target of miR-504 using a luciferase reporter assay and western blot analysis revealed that miR-504 negatively regulated p53 expression at a molecular level. These results indicate that miR-504 contributes to cisplatin resistance in MG63 osteosarcoma cells by suppressing p53. miR-504 may therefore be a potential biomarker for cisplatin resistance in patients with osteosarcoma.

MicroRNA-504 functions as a tumor suppressor in hepatocellular carcinoma through inhibiting Frizzled-7-mediated-Wnt/β-catenin signaling

Accumulating evidence suggests that microRNAs (miRNAs) are critical regulators in the development and progression of various malignant tumors, including hepatocellular carcinoma (HCC). Multiple findings have indicated that miRNA-504 (miR-504) is dysregulated in several types of cancers, functioning as an oncogenic miRNA or a tumor suppressive miRNA. However, the role of miR-504 in HCC remains unknown. In this study, we aimed to detect the expression pattern of miR-504 in HCC tissues and cell lines and investigate the precise biological function in HCC cells. Our results showed that miR-504 expression levels were frequently downregulated in both HCC tissues and cell lines. Gain-of-function experiments demonstrated that miR-504 overexpression inhibited the proliferation and invasion in HCC cell lines. By contrast, miR-504 inhibition had the opposite effect. Interestingly, bioinformatics analysis predicted that Frizzled-7 (FZD7) was a potential target gene of miR-504. Dual-luciferase reporter assays confirmed that miR-504 directly targeted the 3'-untranslated region of FZD7 mRNA. In addition, our results showed that miR-504 negatively regulated the mRNA and protein expression of FZD7 in HCC cell lines. Moreover, miR-540 overexpression inhibited the cellular expression of β-catenin and blocked the activation of Wnt signaling in HCC cells. Notably, restoration of FZD7 expression significantly reversed the inhibitory effect of miR-504 on proliferation, invasion, and Wnt/β-catenin signaling in HCC cells. In conclusion, our results demonstrate that miR-504 functions as a tumor suppressive miRNA that inhibits the proliferation and invasion of HCC cells by targeting FZD7 and inhibiting Wnt/β-catenin signaling. Our study provides evidence that miR-504-meidated FZD7/Wnt/β-catenin signaling pathway plays an important role in HCC development and progression and suggests miR-504 as a novel future therapeutic target for treatment of HCC.

TFF1 antagonizes TIMP-1 mediated proliferative functions in gastric cancer

Tissue inhibitor matrix metalloproteinase-1 (TIMP1) is one of four identified members of the TIMP family. We evaluated the role of TIMP1 in gastric cancer using human and mouse tissues along with gastric organoids and in vitro cell models. Using quantitative real-time RT-PCR, we detected significant overexpression of TIMP1 in the human gastric cancer samples, as compared to normal stomach samples (P < 0.01). We also detected overexpression of Timp1 in neoplastic gastric lesions of the Tff1-knockout (KO) mice, as compared to normal stomach tissues. Reconstitution of TFF1 in human gastric cancer cell lines led to a significant decrease in the mRNA expression level of TIMP1 (P < 0.05). In vitro analysis demonstrated that TIMP1 mRNA expression is induced by TNF-α and activation of NF-κB whereas inhibition of NF-κB using BAY11-7082 led to inhibition of NF-κB and downregulation of TIMP1. Western blot analysis confirmed the decrease in TIMP1 protein level following reconstitution of TFF1. By using immunofluorescence, we showed nuclear localization of NF-κB and expression of TIMP1 in gastric organoids established from the Tff1-KO stomach where reconstitution of Tff1 using recombinant protein led to a notable reduction in the expression of both NF-κB and TIMP1. Using EDU assay, as a measure of proliferating cells, we found that TIMP1 promotes cellular proliferation whereas TFF1 reconstitution leads to a significant decrease in cellular proliferation (P < 0.05). In summary, our findings demonstrate overexpression of TIMP1 in mouse and human gastric cancers through NF-kB-dependent mechanism. We also show that TFF1 suppresses NF-κB and inhibits TIMP1-mediated proliferative potential in gastric cancer.

Methylation of the HOXA10 Promoter Directs miR-196b-5p-Dependent Cell Proliferation and Invasion of Gastric Cancer Cells

The cross-talk between epigenetics and miRNA expression plays an important role in human tumorigenesis. Herein, the regulation and role of miR-196b-5p in gastric cancer was investigated. qRT-PCR demonstrated that miR-196b-5p is significantly overexpressed in human gastric cancer tissues (P < 0.01). In addition, it was determined that HOXA10, a homeobox family member and host gene for miR-196b-5p, is overexpressed and positively correlated with miR-196b-5p expression levels (P < 0.001). Quantitative pyrosequencing methylation analysis demonstrated significantly lower levels of DNA methylation at the HOXA10 promoter in gastric cancer, as compared with nonneoplastic gastric mucosa specimens. 5-Aza-2'-deoxycytidine treatment confirmed that demethylation of HOXA10 promoter induces the expression of HOXA10 and miR-196b-5p in gastric cancer cell model systems. Using the Tff1 knockout mouse model of gastric neoplasia, hypomethylation and overexpression of HOXA10 and miR-196b-5p in gastric tumors was observed, as compared with normal gastric mucosa from Tff1 wild-type mice. Mechanistically, reconstitution of TFF1 in human gastric cancer cells led to an increased HOXA10 promoter methylation with reduced expression of HOXA10 and miR-196b-5p. Functionally, miR-196b-5p reconstitution promoted human gastric cancer cell proliferation and invasion in vitro In summary, the current data demonstrate overexpression of miR-196b-5p in gastric cancer and suggest that TFF1 plays an important role in suppressing the expression of miR-196b-5p by mediating DNA methylation of the HOXA10 promoter. Loss of TFF1 expression may promote proliferation and invasion of gastric cancer cells through induction of promoter hypomethylation and expression of the HOXA10/miR-196b-5p axis.Implications: This study indicates that loss of TFF1 promotes the aberrant overexpression of HOXA10 and miR-196b-5p by demethylation of the HOXA10 promoter, which provides a new perspective of TFF1/HOXA10/miR-196b-5p functions in human gastric cancer. Mol Cancer Res; 16(4); 696-706. ©2018 AACR.

A functional polymorphism in TFF1 promoter is associated with the risk and prognosis of gastric cancer

Trefoil Factor 1 (TFF1, also named pS2), which serves as the gastrointestinal mucosal protector, is known as gastric-specific tumor suppressor gene. However, the genetic variants of TFF1 are still not well studied. In our study, we aim to explore the effects of tagging single nucleotide polymorphisms (tagSNPs) of TFF1 on risk and prognosis of gastric cancer. Seven tagSNPs of TFF1 gene were first analyzed in the discovery set, which was consisted of 753 cases and 950 cancer-free controls. Then, the validation set (940 cases and 1,042 controls) was used for further evaluation. Moreover, we also tested the relation between these tagSNPs and prognosis of gastric cancer (GC). A series of experiments were performed to investigate the underlying mechanisms. We found that rs3761376 AA in the promoter region of TFF1, could reduce the expression of TFF1 by affecting the binding affinity of estrogen receptor 1 (ESR1, ERα), and thereby increased the risk of GC (1.29, 1.08-1.53). Moreover, the rs3761376 AA genotype was also found associated with worse prognosis among patients receiving 5-FU based chemotherapy after surgery (1.71, 1.18-2.48). Further functional assays demonstrated that TFF1 could increase the chemosensitivity of 5-FU by modulating NF-κB targeted genes. These results identified the effect of rs3761376 on TFF1 expression, which accounted for the correlation with susceptibility and prognosis of GC; and this genetic variant may be a potential biomarker to predict the risk and survival of GC.

p73 promotes glioblastoma cell invasion by directly activating POSTN (periostin) expression

Glioblastoma Multiforme is one of the most highly metastatic cancers and constitutes 70% of all gliomas. Despite aggressive treatments these tumours have an exceptionally bad prognosis, mainly due to therapy resistance and tumour recurrence. Here we show that the transcription factor p73 confers an invasive phenotype by directly activating expression of POSTN (periostin, HGNC:16953) in glioblastoma cells. Knock down of endogenous p73 reduces invasiveness and chemo-resistance, and promotes differentiation in vitro. Using chromatin immunoprecipitation and reporter assays we demonstrate that POSTN, an integrin binding protein that has recently been shown to play a major role in metastasis, is a transcriptional target of TAp73. We further show that POSTN overexpression is sufficient to rescue the invasive phenotype of glioblastoma cells after p73 knock down. Additionally, bioinformatics analysis revealed that an intact p73/POSTN axis, where POSTN and p73 expression is correlated, predicts bad prognosis in several cancer types. Taken together, our results support a novel role of TAp73 in controlling glioblastoma cell invasion by regulating the expression of the matricellular protein POSTN.

miR-504 promotes tumour growth and metastasis in human osteosarcoma by targeting TP53INP1

An increasing number of studies have demonstrated that microRNAs participate in the development of osteosarcoma by acting as tumour suppressor or tumour-promoting genes. We investigated the role of miR-504 in the growth and metastasis of osteosarcoma. The expression of miR-504 in clinical osteosarcoma samples was higher than that in the adjacent normal tissue and correlated with tumour size and clinical stage. Tumour protein p53-inducible nuclear protein 1 (TP53INP1) was downregulated in the clinical osteosarcoma samples compared with the adjacent normal tissues and was consistently correlated with the clinical stage. The results of dual-luciferase reporter assay and western blot analysis demonstrated that the TP53INP1 gene is a direct target of miR-504. Altogether, the Cell Counting Kit-8 (CCK-8), the colony formation, the flow cytometry and the Transwell assay results demonstrated that miR-504 promoted osteosarcoma cell growth and metastasis in vitro. P73, P21, Bax, cleaved-caspase-3 and secreted protein acidic and rich in cysteine (SPARC) were associated with the suppressive role of miR-504/TP53INP1. The overexpression of miR-504 in osteosarcoma xenografts enhanced the tumour growth and increased the metastatic burden. Collectively, these results revealed that TP53INP1 is a target gene of miR-504 and that miR-504 enhances osteosarcoma growth and promotes distant metastases by targeting TP53INP1. Thus, miR-504/TP53INP1 may be associated with osteosarcoma size and clinical stage.

Roles of GSK-3 and microRNAs on epithelial mesenchymal transition and cancer stem cells

Various signaling pathways exert critical roles in the epithelial to mesenchymal transition (EMT) and cancer stem cells (CSCs). The Wnt/beta-catenin, PI3K/PTEN/Akt/mTORC, Ras/Raf/MEK/ERK, hedgehog (Hh), Notch and TP53 pathways elicit essential regulatory influences on cancer initiation, EMT and progression. A common kinase involved in all these pathways is moon-lighting kinase glycogen synthase kinase-3 (GSK-3). These pathways are also regulated by micro-RNAs (miRs). TP53 and components of these pathways can regulate the expression of miRs. Targeting members of these pathways may improve cancer therapy in those malignancies that display their abnormal regulation. This review will discuss the interactions of the multi-functional GSK-3 enzyme in the Wnt/beta-catenin, PI3K/PTEN/Akt/mTORC, Ras/Raf/MEK/ERK, Hh, Notch and TP53 pathways. The regulation of these pathways by miRs and their effects on CSC generation, EMT, invasion and metastasis will be discussed.

Heterodimeric interaction between GKN2 and TFF1 entails synergistic antiproliferative and pro-apoptotic effects on gastric cancer cells

BACKGROUND

GKN2 and TFF1 form a heterodimer that is only generated in the mucus-secreting cells of the normal stomach. The formation of this heterodimer is frequently disrupted in gastric cancer. However, the precise roles of GKN2 alone and in the heterodimer with TFF1 as well as the contributions of GKN2 and the heterodimer to gastric carcinogenesis are poorly understood.

METHODS

Cell viability, proliferation, and apoptosis were analyzed in AGS, MKN1, MKN28, and MKN45 gastric cancer cells transfected with GKN2 and/or TFF1 using MTT, BrdU incorporation, and apoptosis assays, respectively. In addition, cell viability was examined in HFE-145 non-neoplastic gastric epithelial cells after GKN2 and/or TFF1 silencing. Furthermore, the cell cycle and the expression of cell cycle and apoptosis related proteins were assessed. The interaction between GKN2 and TFF1 was confirmed by co-immunoprecipitation. Immunohistochemistry was employed to explore TFF1 expression in 169 gastric cancer tissues.

RESULTS

Co-transfection with GKN2 and TFF1 significantly inhibited cell viability and proliferation by inducing G1/S cell cycle arrest and suppressing positive cell cycle regulators. Simultaneous knockdown of GKN2 and TFF1 in HFE-145 cells resulted in markedly increased cell viability. Moreover, the interaction of GKN2 and TFF1 promoted cell death by enhancing caspase-3/7 activity and upregulating pro-apoptotic proteins. At the mRNA level, GKN2 and TFF1 were found to be positively correlated in non-tumor and tumor samples. Immunohistochemistry revealed loss of TFF1 expression in 128 (75.73%) of 169 gastric cancers. There was a borderline-significant association between GKN2 and TFF1 protein expression in gastric cancers (P = 0.0598).

CONCLUSION

Collectively, our data demonstrated that the interaction between GKN2 and TFF1 can have synergistic antiproliferative and pro-apoptotic effects on gastric cancer.

Loss of Tff1 Promotes Pro-Inflammatory Phenotype with Increase in the Levels of RORγt+ T Lymphocytes and Il-17 in Mouse Gastric Neoplasia

Background: TFF1 deficiency induces a mucosal pro-inflammatory phenotype that contributes to gastric tumorigenesis in mouse and human. Methods: We utilized the Tff1-KO mouse model to assess the impact of TFF1 loss on immune cells infiltration in the stomach. We used single cell suspension, flow cytometry, immunohistochemistry, and quantitative PCR (qPCR) assays. Results: The Tff1-KO gastric mucosa demonstrated high chronic inflammatory scores (score: 3-4) at age 2 months, which exacerbated at age 8 months (score: 4-6). We next used single-cell suspensions for flow cytometry analysis of total leukocytes (CD45+ cells), total T lymphocytes (CD45+CD3+cells), T cell subsets (CD4+, CD8+, and CD3+CD4-CD8-cells), and monocytes/macrophages (CD45+F4/80+cells). The results demonstrated an age-dependent (2 → 8 month age) significant increase of leukocytes (p<0.05), T cells (p<0.05), and monocytes/macrophages (p<0.001) in the gastric mucosa of the Tff1-KO mice, as compared to Tff1-WT. A similar increase was observed in blood samples (p<0.05). Using ionomycin to activate CD4⁺ splenocytes, the results indicated that Tff1-KO CD4⁺ splenocytes secreted higher levels of IL-17A (p<0.05 at 2 and p<0.001 at 8 months) and IL-17F (p<0.05 at 2 and 8 months) than Tff1-WT splenocytes. Conversely, Tff1-KO CD8⁺-cells secreted less IL-17F, but comparable levels of IL-17A. In addition, we detected a significant upregulation of Il-17 mRNA expression in gastric tissues in the Tff1-KO, as compared to Tff1-WT (p<0.001). Conclusions: The results identify TFF1 loss as a major pro-inflammatory step that modulates the tumor microenvironment and immune cell infiltration in the stomach. Furthermore, the data suggest that the increase of IL-17A and IL-17F in Th17 cells, derived from CD4⁺ T cells, reflects the chronic inflammation in gastric mucosa, whereas the absence of change of IL-17A and decrease of IL-17F in CD8⁺Tc17 cells suggest loss of cytotoxic function of CD8⁺Tc17 cells during gastric tumorigenesis of the Tff1-KO mice.

miRNA‑504 inhibits p53‑dependent vascular smooth muscle cell apoptosis and may prevent aneurysm formation

Abdominal aortic aneurysm (AAA) is a common disease that is associated with the proliferation and apoptosis of vascular smooth muscle cells (VSMCs). VSMCs are regulated by microRNAs (miRNA). The aim of the present study was to identify miRNA sequences that regulate aortic SMCs during AAA. miRNA-504 was identified using a miRNA PCR array and by reverse transcription-quantitative polymerase chain reaction analysis, and its expression levels were observed to be downregulated in the aortic cells derived from patients with AAA when compared with controls. Transfection of SMCs with pMSCV-miRNA-504 vector was performed, and cell proliferation and the expression levels of proliferating cell nuclear antigen (PCNA), replication factor C subunit 4 (RFC4), B-cell lymphoma-2 (Bcl-2) and caspase-3/9 were measured by western blotting. The mechanisms underlying the effects of miRNA-504 was then analyzed. The results demonstrated that overexpression of miRNA-504 significantly upregulated the expression levels of PCNA, RFC4 and Bcl-2, while caspase-3/9 expression was significantly inhibited when compared with non-targeting controls. In addition, miRNA-504 overexpression was observed to promote the proliferation of SMCs. The expression level of the tumor suppressor, p53, which is known to be a direct target of miRNA-504, was inhibited following transfection of SMCs with pMSCV-miRNA-504. In addition, the expression of the downstream targets of p53, p21 and Bcl-like protein-4, were significantly reduced following overexpression of miRNA-504. These results revealed the anti-apoptotic role of miRNA-504 in SMCs derived from patients with AAA via direct targeting of p53.

Regulatory module involving FGF13, miR-504, and p53 regulates ribosomal biogenesis and supports cancer cell survival

The microRNA miR-504 targets TP53 mRNA encoding the p53 tumor suppressor. miR-504 resides within the fibroblast growth factor 13 (FGF13) gene, which is overexpressed in various cancers. We report that the FGF13 locus, comprising FGF13 and miR-504, is transcriptionally repressed by p53, defining an additional negative feedback loop in the p53 network. Furthermore, we show that FGF13 1A is a nucleolar protein that represses ribosomal RNA transcription and attenuates protein synthesis. Importantly, in cancer cells expressing high levels of FGF13, the depletion of FGF13 elicits increased proteostasis stress, associated with the accumulation of reactive oxygen species and apoptosis. Notably, stepwise neoplastic transformation is accompanied by a gradual increase in FGF13 expression and increased dependence on FGF13 for survival ("nononcogene addiction"). Moreover, FGF13 overexpression enables cells to cope more effectively with the stress elicited by oncogenic Ras protein. We propose that, in cells in which activated oncogenes drive excessive protein synthesis, FGF13 may favor survival by maintaining translation rates at a level compatible with the protein quality-control capacity of the cell. Thus, FGF13 may serve as an enabler, allowing cancer cells to evade proteostasis stress triggered by oncogene activation.

Epigenetic and genetic variation in GATA5 is associated with gastric disease risk

Gastric cancer incidence varies considerably among populations, even those with comparable rates of Helicobacter pylori infection. To test the hypothesis that genetic variation plays a role in gastric disease, we assessed the relationship between genotypes and gastric histopathology in a Colombian study population, using a genotyping array of immune-related single nucleotide polymorphisms (SNPs). Two synonymous SNPs (rs6061243 and rs6587239) were associated with progression of premalignant gastric lesions in a dominant-effects model after correction for multiple comparisons (p = 2.63E-07 and p = 7.97E-07, respectively); effect sizes were β = -0.863 and β = -0.815, respectively, where β is an estimate of effect on histopathology scores, which ranged from 1 (normal) to 5 (dysplasia). In our replication cohort, a second Colombian population, both SNPs were associated with histopathology when additively modeled (β = -0.256, 95 % CI = -0.47, -0.039; and β = -0.239, 95 % CI = -0.45, -0.024), and rs6587239 was significantly associated in a dominant-effects model (β = -0.330, 95 % CI = -0.66, 0.00). Because promoter methylation of GATA5 has previously been associated with gastric cancer, we also tested for the association of methylation status with more advanced histopathology scores in our samples and found a significant relationship (p = 0.001). A multivariate regression model revealed that the effects of both the promoter methylation and the exonic SNPs in GATA5 were independent. A SNP-by-methylation interaction term was also significant. This interaction between GATA5 variants and GATA5 promoter methylation indicates that the association of either factor with gastric disease progression is modified by the other.

Differences in the expression of microRNAs and their predicted gene targets between cauda epididymal and ejaculated boar sperm

Mammalian spermatozoa gradually mature and acquire fertility during the transition from the testis to the caput and cauda epididymis, after which they are stored at the tail of the epididymis and the ampulla of vas deferens. During ejaculation, mixing of spermatozoa with the secretions of accessory sex glands leads to their dilution and changes in their function. Although remarkable progress has been made toward the understanding of changes in spermatozoa biochemistry and function before and after ejaculation, it is unknown whether microRNAs (miRNAs) are involved in regulating the function of spermatozoa during the transition between the cauda epididymis and ejaculation. In this study, 48 miRNAs were selected for analysis on the basis of their potential involvement in spermatogenesis, sperm maturation, and quality parameters markers. The differential expression levels of these 48 miRNAs between the caudal epididymis and fresh ejaculates of boar spermatozoa were determined. We found that 15 miRNAs were significantly differentially expressed (eight downregulated and seven upregulated) between boar cauda epididymal and fresh spermatozoa. Five miRNAs hypothesized to be involved in sperm apoptosis were further tested to demonstrate their influence over the expression of their target mRNAs using quantitative reverse-transcription polymerase chain reaction. Together, our findings suggest that these differentially expressed miRNAs are associated with the functional regulation of spermatozoa between cauda epididymis and ejaculation.

Loss of TFF1 promotes Helicobacter pylori-induced β-catenin activation and gastric tumorigenesis

Using in vitro and in vivo models, we investigated the role of TFF1 in suppressing H. pylori-mediated activation of oncogenic β-catenin in gastric tumorigenesis. A reconstitution of TFF1 expression in gastric cancer cells decreased H. pylori-induced β-catenin nuclear translocation, as compared to control (p < 0.001). These cells exhibited significantly lower β-catenin transcriptional activity, measured by pTopFlash reporter, and induction of its target genes (CCND1 and c-MYC), as compared to control. Because of the role of AKT in regulating β-catenin, we performed Western blot analysis and demonstrated that TFF1 reconstitution abrogates H. pylori-induced p-AKT (Ser473), p-β-catenin (Ser552), c-MYC, and CCND1 protein levels. For in vivo validation, we utilized the Tff1-KO gastric neoplasm mouse model. Following infection with PMSS1 H. pylori strain, we detected an increase in the nuclear staining for β-catenin and Ki-67 with a significant induction in the levels of Ccnd1 and c-Myc in the stomach of the Tff1-KO, as compared to Tff1-WT mice (p < 0.05). Only 10% of uninfected Tff1-KO mice, as opposed to one-third of H. pylori-infected Tff1-KO mice, developed invasive adenocarcinoma (p = 0.03). These findings suggest that loss of TFF1 could be a critical step in promoting the H. pylori-mediated oncogenic activation of β-catenin and gastric tumorigenesis.

miR-504 mediated down-regulation of nuclear respiratory factor 1 leads to radio-resistance in nasopharyngeal carcinoma

microRNAs (miRNAs) are involved in the various processes of DNA damage repair and play crucial roles in regulating response of tumors to radiation therapy. Here, we used nasopharyngeal carcinoma (NPC) radio-resistant cell lines as models and found that the expression of miR-504 was significantly up-regulated. In contrast, the expression of nuclear respiratory factor 1 (NRF1) and other mitochondrial metabolism factors, including mitochondrial transcription factor A (TFAM) and oxidative phosphorylation (OXPHOS) complex III were down-regulated in these cell lines. At the same time, the Seahorse cell mitochondrial stress test results indicated that the mitochondrial respiratory capacity was impaired in NPC radio-resistant cell lines and in a miR-504 over-expressing cell line. We also conducted dual luciferase reporter assays and verified that miR-504 could directly target NRF1. Additionally, miR-504 could down-regulate the expression of TFAM and OXPHOS complexes I, III, and IV and impaired the mitochondrial respiratory function of NPC cells. Furthermore, serum from NPC patients showed that miR-504 was up-regulated during different weeks of radiotherapy and correlated with tumor, lymph nodes and metastasis (TNM) stages and total tumor volume. The radio-therapeutic effect at three months after radiotherapy was evaluated. Results indicated that patients with high expression of miR-504 exhibited a relatively lower therapeutic effect ratio of complete response (CR), but a higher ratio of partial response (PR), compared to patients with low expression of miR-504. Taken together, these results demonstrated that miR-504 affected the radio-resistance of NPC by down-regulating the expression of NRF1 and disturbing mitochondrial respiratory function. Thus, miR-504 might become a promising biomarker of NPC radio-resistance and targeting miR-504 might improve tumor radiation response.

MicroRNA-21 promotes proliferation, invasion and suppresses apoptosis in human osteosarcoma line MG63 through PTEN/Akt pathway

Osteosarcoma, which accounts for 5 % of pediatric tumor, remains the major cause of death among orthopedic malignancies. However, the factors associated with its malignant biological behavior are still poorly understood. MicroRNAs are a class of small noncoding RNAs, which have been considered to associate with malignant progression including cell differentiation, proliferation, apoptosis, invasion, and distant metastasis. In our research, we found that microRNA-21 (miR-21) was significantly overexpressed in human osteosarcoma cell line MG63 compared to human fetal osteoblastic cell line hFOB1.19 by using quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, miR-21 overexpression in MG63 caused a significant raise in cell proliferation and invasion and a significant reduction in cell apoptosis. However, miR-21 underexpression in MG63 caused an opposite result. Western blotting displayed that proteins related with proliferation, apoptosis, and invasion were significantly changed in different groups, respectively. Furthermore, we demonstrated that PTEN may be a potential target of miR-21 in MG63 cells and miR-21 could activate PI3K/Akt pathway by suppressing PTEN expression. In summary, our findings suggested that miR-21 played an active role in osteosarcoma and it could predict the occurrence and development of osteosarcoma.

Trefoil factor family peptides – friends or foes?

Trefoil factor family (TFF) peptides are a group of molecules bearing a characteristic three-loop trefoil domain. They are mainly secreted in mucous epithelia together with mucins but are also synthesized in the nervous system. For many years, TFF peptides were only known for their wound healing and protective function, e.g. in epithelial protection and restitution. However, experimental evidence has emerged supporting a pivotal role of TFF peptides in oncogenic transformation, tumorigenesis and metastasis. Deregulated expression of TFF peptides at the gene and protein level is obviously implicated in numerous cancers, and opposing functions as oncogenes and tumor suppressors have been described. With regard to the regulation of TFF expression, epigenetic mechanisms as well as the involvement of various miRNAs are new, promising aspects in the field of cancer research. This review will summarize current knowledge about the expression and regulation of TFF peptides and the involvement of TFF peptides in tumor biology and cancerogenesis.

Extremely Low-Frequency Electromagnetic Fields Affect the miRNA-Mediated Regulation of Signaling Pathways in the GC-2 Cell Line

Extremely low-frequency electromagnetic fields (ELF-EMFs) can affect male reproductive function, but the underlying mechanism of this effect remains unknown. miRNA-mediated regulation has been implicated as an important epigenetic mechanism for regulatory pathways. Herein, we profiled miRNA expression in response to ELF-EMFs in vitro. Mouse spermatocyte-derived GC–2 cells were intermittently exposed to a 50 Hz ELF-EMF for 72 h (5 min on/10 min off) at magnetic field intensities of 1 mT, 2 mT and 3 mT. Cell viability was assessed using the CCK–8 assay. Apoptosis and the cell cycle were analyzed with flow cytometry. miRNA expression was profiled using Affymetrix Mouse Genechip miRNA 3.0 arrays. Our data showed that the growth, apoptosis or cell cycle arrest of GC–2 cells exposed to the 50 Hz ELF-EMF did not significantly change. However, we identified a total of 55 miRNAs whose expression significantly changed compared with the sham group, including 19 differentially expressed miRNAs (7 miRNAs were upregulated, and 12 were downregulated) in the 1 mT exposure group and 36 (9 miRNAs were upregulated, and 27 were downregulated) in the 3 mT exposure group. The changes in the expression of 15 selected miRNAs measured by real-time PCR were consistent with the microarray results. A network analysis was used to predict core miRNAs and target genes, including miR-30e-5p, miR-210-5p, miR-196b-5p, miR-504-3p, miR-669c-5p and miR-455-3p. We found that these miRNAs were differentially expressed in response to different magnetic field intensities of ELF-EMFs. GO term and KEGG pathway annotation based on the miRNA expression profiling results showed that miRNAs may regulate circadian rhythms, cytokine-cytokine receptor interactions and the p53 signaling pathway. These results suggested that miRNAs could serve as potential biomarkers, and the miRNA-mediated regulation of signaling pathways might play significant roles in the biological effects of ELF-EMFs.

Trefoil factor 1 expression suppresses Helicobacter pylori-induced inflammation in gastric carcinogenesis

BACKGROUND

Infection with Helicobacter pylori, a high-risk factor for gastric cancer, is frequently associated with chronic inflammation through activation of nuclear factor κB (NF-κB). Trefoil factor 1 (TFF1) is a constitutively expressed protein in the stomach that has tumor-suppressor functions and plays a critical role in maintaining mucosal integrity. This study investigated the role of TFF1 in regulating the proinflammatory response to H. pylori infections.

METHODS

For in vitro studies, immunofluorescence, luciferase reporter assays, Western blots, and quantitative real-time polymerase chain reaction were performed to investigate the activation of NF-κB and its target genes in response to infections with H. pylori strains J166 and 7.13. In addition, Tff1-knockout (KO) and Tff1-wild-type mice were used for infections with the H. pylori strain called premouse Sydney strain 1.

RESULTS

The reconstitution of TFF1 expression in gastric cancer cells significantly suppressed H. pylori-mediated increases in NF-κB-p65 nuclear staining, transcriptional activity, and expression of proinflammatory cytokine genes (tumor necrosis factor α, interleukin 1β, chemokine [C-X-C motif] ligand 5, and interleukin 4 receptor) that were associated with reductions in the expression and phosphorylation of NF-κB-p65 and IκB kinase α/β proteins. The in vivo studies using the Tff1-KO mouse model of gastric neoplasia confirmed the in vitro findings. Furthermore, they demonstrated increases in chronic inflammation scores and in the frequency of invasive gastric adenocarcinoma in the Tff1-KO mice infected with H. pylori versus the uninfected Tff1-KO mice.

CONCLUSIONS

These findings underscore an important protective role of TFF1 in abrogating H. pylori-mediated inflammation, a crucial hallmark of gastric tumorigenesis. Therefore, loss of TFF1 expression could be an important step in H. pylori-mediated gastric carcinogenesis.

Trefoil factors: Gastrointestinal-specific proteins associated with gastric cancer

Trefoil factor family (TFF), composed of TFF1, TFF2, and TFF3, is a cluster of secreted peptides characterized by trefoil domain (s) and C-terminal dimerization domain. TFF1, a gastric tumor suppressor, is a single trefoil peptide originally detected in breast cancer cell lines but expressed mainly in the stomach; TFF2, a candidate of gastric cancer suppressor with two trefoil domains, is abundant in the stomach and duodenal Brunner's glands; and TFF3 is another single trefoil peptide expressed throughout the intestine which can promote the development of gastric carcinoma. According to multiple studies, TFFs play a regulatory function in the mammals' digestive system, namely in mucosal protection and epithelial cell reconstruction, tumor suppression or promotion, signal transduction and the regulation of proliferation and apoptosis. Action mechanisms of TFFs remain unresolved, but the recent demonstration of a GKN (gastrokine) 2-TFF1 heterodimer implicates structural and functional interplay with gastrokines. This review aims to encapsulate the structural and biological characteristics of TFF.

Gene and miRNA expression changes in squamous cell carcinoma of larynx and hypopharynx

Laryngo-pharyngeal squamous cell carcinomas are one of the most common head and neck cancers. Despite the presence of a large body of information, molecular biomarkers are not currently used in the diagnosis, treatment and management of patients for this group of cancer. Here, we have profiled expression of genes and microRNAs of larynx and hypopharynx tumors using high-throughput sequencing experiments. We found that matrix metalloproteinases along with SCEL, CRNN, KRT4, SPINK5, and TGM3 among others have significantly altered expression in these tumors. Alongside gene expression, the microRNAs hsa-miR-139, hsa-miR-203 and the hsa-miR-424/503 cluster have aberrant expression in these cancers. Using target genes for these microRNAs, we found the involvement of pathways linked to cell cycle, p53 signaling, and viral carcinogenesis significant (P-values 10(-13), 10(-9) and 10(-7) respectively). Finally, using an ensemble machine-learning tool, we discovered a unique 8-gene signature for this group of cancers that differentiates the group from the other tumor subsites of head and neck region. We investigated the role of promoter methylation in one of these genes, WIF1, and found no correlation between DNA methylation and down-regulation of WIF1. We validated our findings of gene expression, 8-gene signature and promoter methylation using q-PCR, data from TCGA and q-MSP respectively. Data presented in this manuscript has been submitted to the NCBI Geo database with the accession number GSE67994.

Pri-miR-34b/c rs4938723 polymorphism is associated with a decreased risk of gastric cancer

Previous studies have demonstrated that miR-34 family members are abnormally expressed in gastric cancer. Overexpression of the miR-34 family suppresses gastric carcinogenesis, whereas downregulation of the miR-34 family promotes tumorigenesis. p53 can bind to the promoter region of miR-34b/c, leading to an increase of miR-34b/c expression. Recently, a variant in the promoter region of pri-miR-34b/c (rs4938723) has been discovered, with the function of altering the binding efficiency of transcription factor GATA. The purpose of this study was to examine the role of the miR-34b/c rs4938723 and TP53 Arg72Pro polymorphisms in the susceptibility of gastric cancer. We analyzed the distribution of the two polymorphisms in 197 patients with gastric cancer and 289 age-, gender-, ethnicity-, and living area-matched controls using polymerase chain reaction-restriction fragment length polymorphism and DNA direct sequencing. We found that the CT and CT/CC genotypes of the miR-34b/c rs4938723 were associated with a significantly decreased risk of gastric cancer compared with the TT genotype (CT vs. TT: odds ratio [OR]=0.66; 95% confidence interval [95% CI], 0.45-0.97; and CT/CC vs. TT: OR=0.67; 95% CI, 0.47-0.97, respectively). Combined analysis showed that subjects carrying the miR-34b/c rs4938723 CT/CC and TP53 CG/CC genotypes had a 0.62-fold decreased risk to develop gastric cancer compared with subjects carrying the miR-34b/c rs4938723 TT and TP53 CG/CC genotypes (OR=0.62; 95% CI, 0.40-0.96). These findings suggest that the miR-34b/c rs4938723 may individually and jointly have a protective effect on the risk of gastric risk.

Downregulation of microRNA-504 is associated with poor prognosis in high-grade glioma

Several previous reports indicated that microRNA-504 (miR-504) has an oncogenic function through negatively regulating p53. On the other hand, a recent study revealed that miR-504 inhibits cancer cell proliferation through targeting CDK6 in hypopharyngeal squamous cell carcinoma (HSCC), suggesting the tumor suppressive role of this miRNA. However, the role of miR-504 in human malignant glioma remains unclear. Therefore, the aim of this study was to investigate the clinical significance of miR-504 expression in high pathological grade glioma. Quantitative real-time reverse transcriptive-PCR (qRT-PCR) was performed to examine miR-504 expression levels in 63 glioma tissues including 13 anaplastic astrocytomas (AA, WHO grade III) and 50 glioblastomas (GBM, WHO grade IV), as well as 10 non-neoplastic brain tissues. Associations between miR-504 expression and clinicopathological factors and prognosis of glioma patients were statistically analyzed. MiR-504 showed significant decreased expression levels both in AAs and GBMs relative to non-neoplastic brains (P ≤ 0.001, respectively). Additionally, low expression level of miR-504 was significantly associated with advanced WHO grade (P = 0.01). Moreover, Kaplan-Meier survival analysis showed that patients with low expression of miR-504 had significantly poor survival rate (P = 0.002). Cox regression analysis showed that miR-504 expression was independent prognosis-predicting factor for malignant glioma patients (P = 0.038; risk ration = 2.5). Our results suggest that miR-504 may be a prognostic predictor and be involved in tumorigencity as a tumor suppressor of malignant glioma.