The SNAIL/miR-128 axis regulated growth, invasion, metastasis, and epithelial-to-mesenchymal transition of gastric cancer

B-cell-specific Moloney murine leukemia virus integration site 1 knockdown impairs adriamycin resistance of gastric cancer cells

BACKGROUND AND STUDY AIMS

The B-cell-specific Moloney murine leukemia virus integration site 1 (BMI-1) is associated with the progression of gastric cancer (GC). However, its role in drug resistance of gastric cancer stem cell (GCSC) remains unclear. This study aimed to explore the biological function of BMI-1 in GC cells and its role in drug resistance of GCSCs.

PATIENTS AND METHODS

We assessed BMI-1 expression in the GEPIA database and in our collected samples from patients with GC. We silenced BMI-1 using siRNA to study the cell proliferation and migration of GC cells. We also used Hoechst 33342 staining to verify the effect of adriamycin (ADR) on side population (SP) cells, and measured the effects of BMI-1 on the expression of N-cadherin, E-cadherin, and drug-resistance-related proteins (multidrug resistance mutation 1 and lung resistance-related protein). Finally, we analyzed BMI-1-related proteins uing the STRING and GEPIA databases.

RESULTS

BMI-1 mRNA was upregulated in GC tissues and cell lines, especially in MKN-45 and HGC-27 cells. Silencing BMI-1 reduced the proliferation and migration of GC cells. Knocking down BMI-1 significantly decreased epithelial-mesenchymal transition progression, expression levels of drug-resistant proteins, and the number of SP cells in ADR-treated GC cells. Bioinformatics analysis showed that EZH2, CBX8, CBX4, and SUZ12 were positively correlated with BMI-1 in GC tissues.

CONCLUSION

Our study demonstrates that BMI-1 affects the cellular activity, proliferation, migration, and invasion of GC cells. Silencing the BMI-1 gene significantly reduces the number of SP cells and the expression of drug-resistant proteins in ADR-treated GC cells. We speculate that inhibition of BMI-1 increases the drug resistance of GC cells by affecting GCSCs, and that EZH2, CBX8, CBX4, and SUZ12 may participate in BMI-1-induced enhancement of GCSC-like phenotype and viability.

microRNA-128-3p inhibits proliferation and accelerates apoptosis of gastric cancer cells via inhibition of TUFT1

OBJECTIVE

Gastric cancer (GC) is a malignant tumor rooting in the gastric mucosal epithelium, ranking the first among various malignant tumors. Therefore, the influence of microRNA-128-3p (miR-128-3p) by regulation of Tuftelin1 (TUFT1) on GC cells was investigated.

METHODS

The expression levels of miR-128-3p and TUFT1 in GC tissues and cells were detected. The correlation between miR-128-3p expression and overall survival of GC patients was analyzed. Human GC cells MGC803 were transfected with miR-128-3p or TUFT1-related oligonucleotides to figure their roles in viability, apoptosis, invasion, as well as epithelial-mesenchymal transition (EMT). The relationship between miR-128-3p and TUFT1 was validated.

RESULTS

miR-128-3p expression was low and TUFT1 expression was high in GC tissues. miR-128-3p expression was positively correlated with the overall survival of patients with GC. miR-128-3p targeted TUFT1. Up-regulated miR-128-3p or suppressed TUFT1 repressed viability, invasion, and EMT, and accelerated apoptosis of GC cells. Overexpressed TUFT1 reduced miR-128-3p-mediated growth inhibition of GC cells.

CONCLUSION

The study stresses that miR-128-3p can inhibit TUFT1 expression, thereby repressing GC cell activities.

The role of miRNA-128 in the development and progression of gastrointestinal and urogenital cancer

Increasing data have shown the significance of various miRNAs in malignancy. In this regard, parallel to its biological role in normal tissues, miRNA-128 (miR-128) has been found to play an essential immunomodulatory function in the process of cancer initiation and development. The occurrence of the aberrant expression of miR-128 in tumors and the unique properties of miRNAs raise the prospect of their use as biomarkers and the next generation of molecular anticancer therapies. The function of miR-128 in malignancies such as breast, prostate, colorectal, gastric, pancreatic, esophageal, cervical, ovarian and bladder cancers and hepatocellular carcinoma is discussed in this review. Finally, the effect of exosomal miR-128 on cancer resistance to therapeutics and cancer immunotherapy in certain malignancies is highlighted.

The Crucial Roles of Bmi-1 in Cancer: Implications in Pathogenesis, Metastasis, Drug Resistance, and Targeted Therapies

B-cell-specific Moloney murine leukemia virus integration region 1 (Bmi-1, also known as RNF51 or PCGF4) is one of the important members of the PcG gene family, and is involved in regulating cell proliferation, differentiation and senescence, and maintaining the self-renewal of stem cells. Many studies in recent years have emphasized the role of Bmi-1 in the occurrence and development of tumors. In fact, Bmi-1 has multiple functions in cancer biology and is closely related to many classical molecules, including Akt, c-MYC, Pten, etc. This review summarizes the regulatory mechanisms of Bmi-1 in multiple pathways, and the interaction of Bmi-1 with noncoding RNAs. In particular, we focus on the pathological processes of Bmi-1 in cancer, and explore the clinical relevance of Bmi-1 in cancer biomarkers and prognosis, as well as its implications for chemoresistance and radioresistance. In conclusion, we summarize the role of Bmi-1 in tumor progression, reveal the pathophysiological process and molecular mechanism of Bmi-1 in tumors, and provide useful information for tumor diagnosis, treatment, and prognosis.

Long noncoding RNA CCAT1 rs67085638 SNP contribution to the progression of gastric cancer in a Polish population

The role of the long noncoding RNA CCAT1 NC_000008.10:g.128220661C > T (rs67085638) in the development of colon cancer has been reported. Therefore, we assessed the prevalence of rs67085638 in patients with gastric cancer (GC). We also evaluated the effect of rs67085638 on B-cell-specific Moloney leukaemia virus insertion site 1 (BMI1) transcripts in primary GC and counterpart histopathologically confirmed disease-free margin tissue. Using high-resolution melting analysis, we evaluated rs67085638 frequency in patients with the GC genotype (n = 214) and controls (n = 502) in a Polish Caucasian population. qRT-PCR was used to determine BMI1 transcripts. We observed the trend of rs67085638 association in all patients with GC (p_trend = 0.028), a strong risk of the GC genotype in male (p_trend = 0.035) but not female (p_trend = 0.747) patients, and the association with non-cardia GC (p_trend = 0.041), tumour stages T3 (p_trend = 0.014) and T4 (p_trend = 0.032), differentiation grading G3 (p_trend = 0.009), lymph node metastasis stage N3 (p_trend = 0.0005) and metastasis stage M0 (p_trend = 0.027). We found that significantly increased BMI1 transcripts were associated with the primary GC genotype classified as grade G3 (p = 0.011) and as lymph node metastasis N3 (p = 0.010) and counterpart marginal tissues (p = 0.026, p = 0.040, respectively) from carriers of the T/T versus C/C genotypes. rs67085638 may contribute to increased BMI1 transcripts and the progression and rapid growth of GC.

Cir-ITCH inhibits gastric cancer migration, invasion and proliferation by regulating the Wnt/β-catenin pathway

Circular RNAs (circRNAs) are differentially expressed in various tumours, but the expression and regulatory mechanisms of circular RNA ITCH (cir-ITCH) in gastric cancer remain unclear. For this reason, in the present study, we assessed the expression of cir-ITCH and the associated regulatory mechanism of cir-ITCH in gastric cancer. Through RTq-PCR assays, we observed that cir-ITCH expression was attenuated in gastric cancer cell lines and tissues, with cir-ITCH expression in gastric cancer tissues with lymph node metastasis being considerably lower than that observed in gastric cancer tissues without lymph node metastasis. In addition, we demonstrated that cir-ITCH or linear ITCH may be a useful marker for gastric cancer prognosis by Kaplan–Meier survival analysis. We also showed that cir-ITCH overexpression could increase linear ITCH expression through miR-17 via RNA immunoprecipitation (RIP) and luciferase reporter assays. Moreover, in vivo and in vitro experimental results showed that cir-ITCH can act as a tumour suppressor to prevent gastric cancer tumourgenesis by sponging miR-17. The Wnt/β-catenin pathway plays a crucial role during the carcinogenesis of cancers, and we observed that cir-ITCH could negatively regulate Wnt/β-catenin signalling, which could be restored by miR-17. In summary, cir-ITCH was shown to prevent gastric cancer tumourgenesis through the Wnt/β-catenin signalling pathway by sequestering miR-17.

PI3K/AKT/mTOR signaling in gastric cancer: Epigenetics and beyond

PI3K/AKT/mTOR pathway is one of the most important signaling pathways involved in normal cellular processes. Its aberrant activation modulates autophagy, epithelial-mesenchymal transition, apoptosis, chemoresistance, and metastasis in many human cancers. Emerging evidence demonstrates that some infections as well as epigenetic regulatory mechanisms can control PI3K/AKT/mTOR signaling pathway. In this review, we focused on the role of this pathway in gastric cancer development, prognosis, and metastasis, with an emphasis on epigenetic alterations including DNA methylation, histone modifications, and post-transcriptional modulations through non-coding RNAs fluctuations as well as H. pylori and Epstein-Barr virus infections. Finally, we reviewed different molecular targets and therapeutic agents in clinical trials as a potential strategy for gastric cancer treatment through the PI3K/AKT/mTOR pathway.

MiR-128 suppresses metastatic capacity by targeting metadherin in breast cancer cells

Background

Breast cancer, the most common cancer in women worldwide, causes the vast majority of cancer-related deaths. Undoubtedly, tumor metastasis and recurrence are responsible for more than 90 percent of these deaths. MicroRNAs are endogenous noncoding RNAs that have been integrated into almost all the physiological and pathological processes, including metastasis. In the present study, the role of miR-128 in breast cancer was investigated.

Results

Compared to the corresponding adjacent normal tissue, the expression of miR-128 was significantly suppressed in human breast cancer specimens. More importantly, its expression level was reversely correlated to histological grade of the cancer. Ectopic expression of miR-128 in the aggressive breast cancer cell line MDA-MB-231 could inhibit cell motility and invasive capacity remarkably. Afterwards, Metadherin (MTDH), also known as AEG-1 (Astrocyte Elevated Gene 1) and Lyric that implicated in various aspects of cancer progression and metastasis, was further identified as a direct target gene of miR-128 and its expression level was up-regulated in clinical samples as expected. Moreover, knockdown of MTDH in MDA-MB-231 cells obviously impaired the migration and invasion capabilities, whereas re-expression of MTDH abrogated the suppressive effect caused by miR-128.

Conclusions

Overall, these findings demonstrate that miR-128 could serve as a novel biomarker for breast cancer metastasis and a potent target for treatment in the future.

MicroRNAs in gastric cancer: Biomarkers and therapeutic targets

MicroRNAs (miRNAs) are a group of non-coding RNAs that have critical roles in regulation of expression of genes. They can inhibit or decrease expression of target genes mostly via interaction with 3' untranslated region of their targets. Their crucial roles in the regulation of expression of tumor suppressor genes and oncogenes have potentiated them as contributors in tumorigenesis. Moreover, their stability in body fluids has enhanced their potential as cancer biomarkers. In the present review article, we describe the role of miRNAs in the pathogenesis of gastric cancer and advances in application of miRNAs as biomarkers and therapeutic targets in this kind of malignancy.

PAICS, a De Novo Purine Biosynthetic Enzyme, Is Overexpressed in Pancreatic Cancer and Is Involved in Its Progression

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with an extremely poor prognosis. There is an urgent need to identify new therapeutic targets and also understand the mechanism of PDAC progression that leads to aggressiveness of the disease. To find therapeutic targets, we analyzed data related to PDAC transcriptome sequencing and found overexpression of the de novo purine metabolic enzyme phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS). Immunohistochemical analysis of PDAC tissues showed high expression of the PAICS protein. To assess the biological roles of PAICS, we used RNA interference and knock down of its expression in PDAC cell lines that caused a reduction in PDAC cell proliferation and invasion. Furthermore, results of chorioallantoic membrane assays and pancreatic cancer xenografts demonstrated that PAICS regulated pancreatic tumor growth. Our data also showed that, in PDAC cells, microRNA-128 regulates and targets PAICS. PAICS depletion in PDAC cells caused upregulation in E-cadherin, a marker of the epithelial-mesenchymal transition. In PDAC cells, a BET inhibitor, JQ1, reduced PAICS expression. Thus, our investigations show that PAICS is a therapeutic target for PDAC and, as an enzyme, is amenable to targeting by small molecules.

Epithelial-Mesenchymal Transition: Role in Cancer Progression and the Perspectives of Antitumor Treatment

About 90% of all malignant tumors are of epithelial nature. The epithelial tissue is characterized by a close interconnection between cells through cell-cell interactions, as well as a tight connection with the basement membrane, which is responsible for cell polarity. These interactions strictly determine the location of epithelial cells within the body and are seemingly in conflict with the metastatic potential that many cancers possess (the main criteria for highly malignant tumors). Tumor dissemination into vital organs is one of the primary causes of death in patients with cancer. Tumor dissemination is based on the so-called epithelial-mesenchymal transition (EMT), a process when epithelial cells are transformed into mesenchymal cells possessing high mobility and migration potential. More and more studies elucidating the role of the EMT in metastasis and other aspects of tumor progression are published each year, thus forming a promising field of cancer research. In this review, we examine the most recent data on the intracellular and extracellular molecular mechanisms that activate EMT and the role they play in various aspects of tumor progression, such as metastasis, apoptotic resistance, and immune evasion, aspects that have usually been attributed exclusively to cancer stem cells (CSCs). In conclusion, we provide a detailed review of the approved and promising drugs for cancer therapy that target the components of the EMT signaling pathways.

MicroRNA-128-3p Enhances the Chemosensitivity of Temozolomide in Glioblastoma by Targeting c-Met and EMT

Temozolomide is a first line anti-tumor drug used for the treatment of patients with Glioblastoma multiforme (GBM). However, the drug resistance to temozolomide limits its clinical application. Therefore, novel strategies to overcome chemoresistance are desperately needed for improved treatment of human GBM. Recent studies have demonstrated that miRNAs are closely related to resistance to cancer chemotherapy. This study aimed to further validate the biological role of miR-128-3p and to investigate whether miR-128-3p can enhance the chemosensitivity of glioblastoma to temozolomide (TMZ) and the underlying mechanisms. The effects of miR-128-3p and TMZ on the proliferation of glioblastoma cells were investigated by cell counting kit-8 (cck8). Transwell and intracerebral invasion assays were applied to determine the effects of the combination of miR-128-3p and TMZ on the invasion and migration of glioblastoma in vitro and in vivo. Flow cytometry was used to detect apoptosis in each group, and immunofluorescence was used to determine the expression levels of EMT-related proteins. RT-PCR and Western-blot were applied to detect EMT-transformed proteins (c-Met, PDGFRα, Notch1, and Slug) and EMT phenotype-associated proteins (Vim, CD44, and E-cadherin) at both mRNA and protein levels. Based on the microRNA.org database, we predicted the target genes of miR-128-3p. The target-relationship between miR-128-3p and c-Met and PDGFRα was verified by dual luciferase reporter gene. The tumor volume, weight and the expression levels of the proteins described above were measured in subcutaneously transplanted tumor model in nude mice. We found that the expression of miR-128-3p was down-regulated in glioblastoma tissue samples and cell lines. miR-128-3p suppressed the proliferation, migration, and invasion of GBM both in vitro and in vivo; miR-128-3p enhanced the therapeutic effect of TMZ via inhibition of proliferation, invasion and migration of glioblastoma cells and induction of apoptosis. Overexpression of miR-128-3p down-regulated the expression levels of EMT-transformed proteins (c-Met, PDGFRα, Notch1 and Slug) to enhance the effect of TMZ. In addition, we found that miR-128-3p targeted and bound c-Met. More importantly, the upregulation of c‐Met significantly prompted U87 and U251 cell proliferation. This effect could be abolished when c‐Met was silenced. The investigation in tumor bearing nude mice showed that miR-128-3p in combination with TMZ reduced tumor volume and the invasion extent, and increased the sensitivity of glioblastoma to TMZ. miR-128-3p is capable of enhancing the sensitivity of glioblastoma to TMZ through regulating c-Met/EMT.

The regulatory mechanism and biological significance of the Snail-miR590-VEGFR-NRP1 axis in the angiogenesis, growth and metastasis of gastric cancer

Vascular endothelial growth factor receptor (VEGFR) and neuropilins (NRPs), a co-receptor of VEGF, play a key role in the formation and development of blood vessels and in tumour growth and metastasis. However, whether VEGFR1/2 and NRP1 are regulated by the same upstream mechanism is unclear, especially in gastric cancer. We used prediction tools to detect miRNAs that may simultaneously regulate VEGFR1/2 and NRP1, and we finally determined that miR-590 can simultaneously regulate VEGFR1/2 and NRP1 in gastric cancer. We discovered that miR-590 was downregulated in gastric cancer tissues and cell lines, and this was related to the dysregulation of the transcription factor SNAIL. In addition, the overexpression of miR-590 inhibits the migration, invasion, proliferation and D-MVA levels of gastric cancer cells in vivo and in vitro by targeting VEGFR1/2 and NRP1. We also demonstrated that miR-590 may be a useful marker for the prognosis of gastric cancer with Kaplan–Meier survival analysis. Since the epithelial-to-mesenchymal transition (EMT) is an important mechanism of tumour invasion and metastasis and VEGFR1/2 and NRP1 can promote the occurrence of EMT, we speculated that miR-590 can regulate the occurrence of EMT. Immunoblot and immunofluorescence analyses confirmed that the overexpression of miR-590 can inhibit the EMT in gastric cancer cells. Since SNAIL is also a mesenchymal marker, our results revealed a new, positive feedback loop. As a transcription factor, SNAIL inhibits the expression of miR-590, thereby upregulating the expression levels of NRP1 and VEGFR1/2; this leads to the development of EMT in gastric cancer and the upregulation of SNAIL.

MicroRNA (miR) dysregulation during Helicobacter pylori-induced gastric inflammation and cancer development: critical importance of miR-155

Dysregulation of noncoding microRNA molecules has been associated with immune cell activation in the context of Helicobacter pylori induced gastric inflammation as well as carcinogenesis, but also with downregulation of mismatch repair genes, and may interfere with immune checkpoint proteins that lead to the overexpression of antigens on gastric tumor cells. Numerous miR-molecules have been described as important tools and markers in gastric inflammation and cancer development -including miR-21, miR-143, miR-145, miR-201, and miR-335- all of which are downregulated in gastric tumors, and involved in cell cycle growth or tumor invasion. Among the many microRNAs involved in gastric inflammation, adenocarcinoma development and immune checkpoint regulation, miR-155 is notable in that its upregulation is considered a key marker of chronic gastric inflammation that predisposes a patient to gastric carcinogenesis. Among various other miRs, miR-155 is highly expressed in activated B and T cells and in monocytes/macrophages present in chronic gastric inflammation. Notably, miR-155 was shown to downregulate the expression of certain MMR genes, such as MLH1, MSH2, and MSH6. In tumor-infiltrating miR-155-deficient CD8⁺ T cells, antibodies against immune checkpoint proteins restored the expression of several derepressed miR-155 targets, suggesting that miR-155 may regulate overlapping pathways to promote antitumor immunity. It may thus be of high clinical impact that gastric pathologies mediated by miR-155 result from its overexpression. This suggests that it may be possible to therapeutically attenuate miR-155 levels for gastric cancer treatment and/or to prevent the progression of chronic gastric inflammation into cancer.

PVT1 Long Non-coding RNA in Gastrointestinal Cancer

Whole genome and transcriptome sequencing technologies have led to the identification of many long non-coding RNAs (lncRNAs) and stimulated the research of their role in health and disease. LncRNAs participate in the regulation of critical signaling pathways including cell growth, motility, apoptosis, and differentiation; and their expression has been found dysregulated in human tumors. Thus, lncRNAs have emerged as new players in the initiation, maintenance and progression of tumorigenesis. PVT1 (plasmacytoma variant translocation 1) lncRNA is located on chromosomal 8q24.21, a large locus frequently amplified in human cancers and predictive of increased cancer risk in genome-wide association studies (GWAS). Combined, colorectal and gastric adenocarcinomas are the most frequent tumor malignancies and also the leading cause of cancer-related deaths worldwide. PVT1 expression is elevated in gastrointestinal tumors and correlates with poor patient prognosis. In this review, we discuss the mechanisms of action underlying PVT1 oncogenic role in colorectal and gastric cancer such as MYC upregulation, miRNA production, competitive endogenous RNA (ceRNA) function, protein stabilization, and epigenetic regulation. We also illustrate the potential role of PVT1 as prognostic biomarker and its relationship with resistance to current chemotherapeutic treatments.

Interplay among SNAIL Transcription Factor, MicroRNAs, Long Non-Coding RNAs, and Circular RNAs in the Regulation of Tumor Growth and Metastasis

SNAIL (SNAI1) is a zinc finger transcription factor that binds to E-box sequences and regulates the expression of genes. It usually acts as a gene repressor, but it may also activate the expression of genes. SNAIL plays a key role in the regulation of epithelial to mesenchymal transition, which is the main mechanism responsible for the progression and metastasis of epithelial tumors. Nevertheless, it also regulates different processes that are responsible for tumor growth, such as the activity of cancer stem cells, the control of cell metabolism, and the regulation of differentiation. Different proteins and microRNAs may regulate the SNAIL level, and SNAIL may be an important regulator of microRNA expression as well. The interplay among SNAIL, microRNAs, long non-coding RNAs, and circular RNAs is a key event in the regulation of tumor growth and metastasis. This review for the first time discusses different types of regulation between SNAIL and non-coding RNAs with a focus on feedback loops and the role of competitive RNA. Understanding these mechanisms may help develop novel therapeutic strategies against cancer based on microRNAs.

MiR-128-3p Post-Transcriptionally Inhibits WISP1 to Suppress Apoptosis and Inflammation in Human Articular Chondrocytes via the PI3K/AKT/NF-κB Signaling Pathway

In osteoarthritis (OA), the synthesis and decomposition of the extracellular matrix (ECM) are imbalanced. High expression levels of Wnt1-inducible signaling pathway protein 1 (WISP1) promote the synthesis of matrix metalloproteinases and induce the degradation of cartilage, which aggravates the OA. The aim of this study was to explore the role of miR-128-3p in the development of OA. In the present study, the expression of WISP1 and miR-128-3p in osteoarthritic tissues and chondrocytes was detected using quantitative reverse transcription PCR (RT-qPCR) and Western blotting. Then we predicted that WISP1 might be a potential target gene of miR-128-3p by TargetScan and verified using luciferase reporter gene assay. The effect of miR-128-3p or WISP1 on chondrocytes was evaluated by cell proliferation assay, apoptosis, and caspase-3 activity assay. To further reveal the molecular mechanisms of miR-128-3p in osteoarthritic development, the degradation of chondrocyte matrix and production of proinflammatory cytokines in osteoarthritic chondrocyte model were detected by ELISA. To mimic the osteoarthritic microenvironment in vitro studies, chondrocytes were stimulated with interleukin (IL)-1β, and then we found that the expression of miR-128-3p was downregulated. Overexpression of WISP1 inhibited the proliferation of chondrocytes, which induced apoptosis, degradation of chondrocyte matrix, production of proinflammatory cytokines, and activated the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. Then, we identified that miR-128-3p was a negative regulator of WISP1 by directly targeting its 3'-untranslated region (UTR). Moreover, the PI3K allosteric activator 740 Y-P abolished the inhibition of miR-128-3p in apoptosis, degradation of chondrocyte matrix, and inflammation. Our results showed that miR-128-3p targets WISP1 to regulate chondrocyte proliferation, apoptosis, degradation of chondrocyte matrix, and production of proinflammatory cytokines via the PI3K/Akt/NF-κB pathway, which plays a suppressed role in OA.

miR-128-3p contributes to mitochondrial dysfunction and induces apoptosis in glioma cells via targeting pyruvate dehydrogenase kinase 1

Glioma, like most cancers, possesses a unique bioenergetic state of aerobic glycolysis known as the Warburg effect, which is a dominant phenotype of most tumor cells. Glioma tumors exhibit high glycolytic metabolism with increased lactate production. Data derived from the gene expression profiling interactive analysis (GEPIA) database show that pyruvate dehydrogenase kinase 1 (PDK1) is significantly highly expressed in glioma tissues compared with corresponding normal tissues. PDK1 is a key enzyme in the transition of glycolysis to tricarboxylic acid cycle, via inactivating PDH and converting oxidative phosphorylation to Warburg effect, resulting in increment of lactate production. Silencing of PDK1 expression resulted in reduced lactate and ATP, accumulation of ROS, mitochondrial damage, decreased cell growth, and increased cell apoptosis. Aberrant expression of miR-128 has been observed in many human malignancies. Mechanistically, we discover that overexpressed miR-128-3p disturbs the Warburg effect in glioma cells via reducing PDK1. Our experiments confirmed that the miR-128-3p/PDK1 axis played a pivotal role in cancer cell metabolism and growth. Collectively, these findings suggest that therapeutic strategies to modulate the Warburg effect, such as targeting of PDK1, might act as a potential therapeutic target for glioma treatment.

Chronic myelogenous leukemia cells remodel the bone marrow niche via exosome-mediated transfer of miR-320

Rationale: Reciprocal interactions between leukemic cells and bone marrow mesenchymal stromal cells (BMMSC) remodel the normal niche into a malignant niche, leading to leukemia progression. Exosomes have emerged as an essential mediator of cell-cell communication. Whether leukemic exosomes involved in bone marrow niche remodeling remains unknown. Methods: We investigated the role of leukemic exosomes in molecular and functional changes of BMMSC in vitro and in vivo. RNA sequencing and bioinformatics were employed to screen for miRNAs that are selectively sorted into leukemic exosomes and the corresponding RNA binding proteins. Results: We demonstrated that leukemia cells significantly inhibited osteogenesis by BMMSC both in vivo and in vitro. Some tumor suppressive miRNAs, especially miR-320, were enriched in exosomes and thus secreted by leukemic cells, resulting in increased proliferation of the donor cells. In turn, the secreted exosomes were significantly endocytosed by adjacent BMMSC and thus inhibited osteogenesis at least partially via β-catenin inhibition. Mechanistically, miR-320 and some other miRNAs were sorted out into the exosomes by RNA binding protein heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1), as these miRNAs harbor the recognition site for HNRNPA1. Conclusion: HNRNPA1-mediated exosomal transfer of miR-320 from leukemia cells to BMMSC is an important mediator of leukemia progression and is a potential therapeutic target for CML.

MicroRNA-128/homeobox B8 axis regulates ovarian cancer cell progression

MicroRNA-128 (miR-128) has been found to be dysregulated and might function as a tumour suppressor in various cancers, including ovarian cancer. However, the underlying mechanism of miR-128 in ovarian cancer has not been fully understood. The miR-128 and homeobox B8 (HOXB8) levels in clinical samples and cultured cell lines were measured using qRT-PCR and/or Western blot analysis. Cell proliferation was assessed using Cell Counting Kit-8 assay. Cell apoptosis was determined using flow cytometry. The association between miR-128 and HOXB8 was confirmed using dual-luciferase reporter assay. Results showed that decreased miR-128 expression and increased HOXB8 expression were observed in ovarian cancer tissues and cell lines. Transfection with miR-128 mimics suppressed the cell proliferation and enhanced paclitaxel sensitivity in ovarian cancer cell lines. miR-128 directly targeted HOXB8 in ovarian cancer cell lines. Knockdown of HOXB8 abolished the effects of miR-128 inhibitor on ovarian cancer cell proliferation and paclitaxel sensitivity. Summarily, miR-128 displayed a tumour suppressor role in ovarian cancer via targeting HOXB8. It is supposed that miR-128 might be effective for targeting therapy for ovarian cancer.

Non-coding RNAs in regulating gastric cancer metastasis

Gastric cancer is one of the leading causes of cancer-related deaths worldwide, and mortality remains high, especially in East Asia. At present, the main method to diagnose gastric cancer is pathological biopsy. At the time of diagnosis, most patients have been diagnosed with advanced cancer and metastasis. The treatment of gastric cancer patients is mainly radical surgical resection and chemoradiotherapy, while patients with metastatic tumor have great challenges to radical surgery and are prone to drug resistance. Metastasis is an important factor affecting tumor development. In addition, evidence accumulated in the literature indicates that non-coding RNA plays a key role in tumor metastasis. This article reviews the role of ncRNAs in gastric cancer metastasis and discusses the regulatory mechanism in the development and treatment of gastric cancer.

Methylation‑associated silencing of miR‑128 promotes the development of esophageal cancer by targeting COX‑2 in areas with a high incidence of esophageal cancer

Esophageal cancer is one of the most common cancer types in the world, with a widely varying incidence between different regions. Zinc deficiency (ZD) is very common in high‑risk areas for esophageal cancer. Dietary ZD is reported to be associated with esophageal squamous cell carcinoma (ESCC). In the current study, the effects of ZD on tumorigenesis and expression of inflammatory factors were investigated in mice. It was identified that a ZD diet advanced ESCC and increased the expression of cyclooxygenase‑2 (COX‑2) prior to the occurrence of ESCC in mice. ZD significantly enhanced DNA methyltransferase (DNMT) activity and increased the expression of DNMT1 and DNMT3B. Furthermore, the expression of miR‑128 was downregulated by methylation, and COX‑2, a direct target of miR‑128, was upregulated with the reduction in miR‑128. Upregulation of miR‑128 inhibited the cell cycle, proliferation and metastasis, and the expression of COX‑2, cyclin D1 and retinoblastoma protein (Rb). Furthermore, the relative expression level of miR‑128 was negatively associated with COX‑2 in ESCC tissues. Collectively, these findings indicate that methylation‑associated silencing of miR‑128 promotes the development of esophageal cancer through upregulation of the expression of cyclin D1 and Rb by targeting COX‑2 in ZD regions with a high incidence of esophageal cancer.

Molecular alterations of cancer cell and tumour microenvironment in metastatic gastric cancer

The term metastasis is widely used to describe the endpoint of the process by which tumour cells spread from the primary location to an anatomically distant site. Achieving successful dissemination is dependent not only on the molecular alterations of the cancer cells themselves, but also on the microenvironment through which they encounter. Here, we reviewed the molecular alterations of metastatic gastric cancer (GC) as it reflects a large proportion of GC patients currently seen in clinic. We hope that further exploration and understanding of the multistep metastatic cascade will yield novel therapeutic targets that will lead to better patient outcomes.

MicroRNA-216a inhibits the metastasis of gastric cancer cells by targeting JAK2/STAT3-mediated EMT process

MicroRNAs (miRNAs), a group of small, non-protein coding, endogenous RNAs, play critical roles in the tumorigenesis and progression of human cancer. miR-216a has recently been reported to play an oncogenic role in human cancer. While, the expression of miR-216a, its biological function and underlying molecular mechanisms in gastric cancer (GC) are largely unknown. In this study, we revealed that miR-216a was underexpressed in GC tissues compared to matched noncancerous tissues. Decreased levels of miR-216a were confirmed in GC cell lines compared with a normal gastric epithelium cell line. miR-216a underexpression was associated with malignant prognostic features including lymph node metastasis, venous infiltration, invasive depth and advanced TNM stage. GC patients with low miR-216a level showed an obvious shorter overall survival. miR-216a overexpression restrained migration and invasion of MGC-803 cells, while its knockdown exerted opposite effects on metastatic behaviors of SGC-7901 cells. In vivo experiments found that miR-216a restoration reduced metastatic nodes of GC cells in nude mice liver. miR-216a notably suppressed epithelial-mesenchymal transition (EMT) of GC cells. Janus kinase 2 (JAK2) was recognized as a direct target and downstream mediator of miR-216a in GC cells. Interestingly, JAK2/signal transducer and activator of transcription 3 (STAT3) pathway was prominently inactivated by miR-216a and probably mediated the role of miR-216a in the regulation of migration, invasion and EMT process of GC cells. In conclusion, these data suggest that miR-216a functions as a tumor suppressive miRNA in the development of GC possibly by targeting JAK2/STAT3-mediated EMT.