Methylation-mediated silencing of miR-133a-3p promotes breast cancer cell migration and stemness via miR-133a-3p/MAML1/DNMT3A positive feedback loop

From molecular pathogenesis to therapy: Unraveling non-coding RNAs/DNMT3A axis in human cancers

Cancer is a comprehensive classification encompassing more than 100 forms of malignancies that manifest in diverse tissues within the human body. Recent studies have provided evidence that aberrant epigenetic modifications are pivotal indicators of cancer. Epigenetics encapsulates DNA methyltransferases as a crucial class of modifiers. DNMTs, including DNMT3A, assume central roles in DNA methylation processes that orchestrate normal biological functions, such as gene transcription, predominantly in mammals. Typically, deviations in DNMT3A function engender distortions in factors that drive tumor growth and progression, thereby exacerbating the malignant phenotype of tumors. Consequently, such abnormalities pose significant challenges in cancer therapy because they impede treatment efficacy. Non-coding RNAs (ncRNAs) represent a group of RNA molecules that cannot encode functional proteins. Recent investigation attests to the crucial significance of regulatory ncRNAs in epigenetic regulation. Notably, recent reports have illuminated the complex interplay between ncRNA expression and epigenetic regulatory machinery, including DNMT3A, particularly in cancer. Recent findings have demonstrated that miRNAs, namely miR-770-5p, miR-101, and miR-145 exhibit the capability to target DNMT3A directly, and their aberration is implicated in diverse cellular abnormalities that predispose to cancer development. This review aims to articulate the interplay between DNMT3A and the ncRNAs, focusing on its impact on the development and progression of cancer, cancer therapy resistance, cancer stem cells, and prognosis. Importantly, the emergence of such reports that suggest a connection between DNMT3A and ncRNAs in several cancers indicates that this connecting axis offers a valuable target with significant therapeutic potential that might be exploited for cancer management.

DNMT3A Cooperates with YAP/TAZ to Drive Gallbladder Cancer Metastasis

Gallbladder cancer (GBC) is an extremely lethal malignancy with aggressive behaviors, including liver or distant metastasis; however, the underlying mechanisms driving the metastasis of GBC remain poorly understood. In this study, it is found that DNA methyltransferase DNMT3A is highly expressed in GBC tumor tissues compared to matched adjacent normal tissues. Clinicopathological analysis shows that DNMT3A is positively correlated with liver metastasis and poor overall survival outcomes in patients with GBC. Functional analysis confirms that DNMT3A promotes the metastasis of GBC cells in a manner dependent on its DNA methyltransferase activity. Mechanistically, DNMT3A interacts with and is recruited by YAP/TAZ to recognize and access the CpG island within the CDH1 promoter and generates hypermethylation of the CDH1 promoter, which leads to transcriptional silencing of CDH1 and accelerated epithelial-to-mesenchymal transition. Using tissue microarrays, the association between the expression of DNMT3A, YAP/TAZ, and CDH1 is confirmed, which affects the metastatic ability of GBC. These results reveal a novel mechanism through which DNMT3A recruitment by YAP/TAZ guides DNA methylation to drive GBC metastasis and provide insights into the treatment of GBC metastasis by targeting the functional connection between DNMT3A and YAP/TAZ.

Epigenetic regulation of bone remodeling and bone metastasis

Bone remodeling is a continuous and dynamic process of bone formation and resorption to maintain its integrity and homeostasis. Bone marrow is a source of various cell lineages, including osteoblasts and osteoclasts, which are involved in bone formation and resorption, respectively, to maintain bone homeostasis. Epigenetics is one of the elementary regulations governing the physiology of bone remodeling. Epigenetic modifications, mainly DNA methylation, histone modifications, and non-coding RNAs, regulate stable transcriptional programs without causing specific heritable alterations. DNA methylation in CpG-rich promoters of the gene is primarily correlated with gene silencing, and histone modifications are associated with transcriptional activation/inactivation. However, non-coding RNAs regulate the metastatic potential of cancer cells to metastasize at secondary sites. Deregulated or altered epigenetic modifications are often seen in many cancers and interwound with bone-specific tropism and cancer metastasis. Histone acetyltransferases, histone deacetylase, and DNA methyltransferases are promising targets in epigenetically altered cancer. High throughput epigenome mapping and targeting specific epigenetics modifiers will be helpful in the development of personalized epi-drugs for advanced and bone metastasis cancer patients. This review aims to discuss and gather more knowledge about different epigenetic modifications in bone remodeling and metastasis. Further, it provides new approaches for targeting epigenetic changes and therapy research.

The Mechanism of DNA Methylation and miRNA in Breast Cancer

Breast cancer is the most prevalent cancer in the world. Currently, the main treatments for breast cancer are radiotherapy, chemotherapy, targeted therapy and surgery. The treatment measures for breast cancer depend on the molecular subtype. Thus, the exploration of the underlying molecular mechanisms and therapeutic targets for breast cancer remains a hotspot in research. In breast cancer, a high level of expression of DNMTs is highly correlated with poor prognosis, that is, the abnormal methylation of tumor suppressor genes usually promotes tumorigenesis and progression. MiRNAs, as non-coding RNAs, have been identified to play key roles in breast cancer. The aberrant methylation of miRNAs could lead to drug resistance during the aforementioned treatment. Therefore, the regulation of miRNA methylation might serve as a therapeutic target in breast cancer. In this paper, we reviewed studies on the regulatory mechanisms of miRNA and DNA methylation in breast cancer from the last decade, focusing on the promoter region of tumor suppressor miRNAs methylated by DNMTs and the highly expressed oncogenic miRNAs inhibited by DNMTs or activating TETs.

Crosstalk between miRNAs and DNA Methylation in Cancer

miRNAs are some of the most well-characterized regulators of gene expression. Integral to several physiological processes, their aberrant expression often drives the pathogenesis of both benign and malignant diseases. Similarly, DNA methylation represents an epigenetic modification influencing transcription and playing a critical role in silencing numerous genes. The silencing of tumor suppressor genes through DNA methylation has been reported in many types of cancer and is associated with tumor development and progression. A growing body of literature has described the crosstalk between DNA methylation and miRNAs as an additional layer in the regulation of gene expression. Methylation in miRNA promoter regions inhibits its transcription, while miRNAs can target transcripts and subsequently regulate the proteins responsible for DNA methylation. Such relationships between miRNA and DNA methylation serve an important regulatory role in several tumor types and highlight a novel avenue for potential therapeutic targets. In this review, we discuss the crosstalk between DNA methylation and miRNA expression in the pathogenesis of cancer and describe how miRNAs influence DNA methylation and, conversely, how methylation impacts the expression of miRNAs. Finally, we address how these epigenetic modifications may be leveraged as biomarkers in cancer.

MiR-133a/CD47 axis is a novel prognostic biomarker to promote triple negative breast cancer progression

Cluster of differentiation 47 (CD47) acts as an anti-engulfment signal on tumor cells, and its overexpression is correlated with poor prognosis of various malignant tumors. However, the role and mechanism of CD47 in tumor cell proliferation, migration and apoptosis remain unclarified. Emerging evidence indicates that microRNAs (miRNAs) are potential regulators to mediate CD47 generation. In this study, we found that CD47 was up-regulated while miR-133a was down-regulated in triple-negative breast cancer (TNBC) in vitro and in vivo. Moreover, we demonstrated for the first time that CD47 was a direct target of miR-133a in TNBC cells, and provided direct evidence of the inverse correlation between miR-133a and CD47 expression in TNBC. Besides, miR-133a functioned as a tumor suppressor to inhibit proliferation and migration, and promote apoptosis of TNBC cells by targeting CD47. Furthermore, overexpression of miR-133a inhibited the tumor growth of TNBC in an in vivo xenograft animal model by targeting CD47. Thus, miR-133a/CD47 axis provides new insight into the mechanism of TNBC progression and could be a promising candidate in the diagnosis and treatment of TNBC.

Crosstalk between Methylation and ncRNAs in Breast Cancer: Therapeutic and Diagnostic Implications

Breast cancer, as a highly heterogeneous malignant tumor, is one of the primary causes of death among females worldwide. The etiology of breast cancer involves aberrant epigenetic mechanisms and abnormal expression of certain non-coding RNA (ncRNAs). DNA methylation, N6-methyladenosine(m6A), and histone methylation are widely explored epigenetic regulation types in breast cancer. ncRNAs are a group of unique RNA transcripts, mainly including microRNA (miRNAs), long non-coding RNA (lncRNAs), circular RNA (circRNAs), small interfering RNA (siRNAs), piwi-interacting RNA (piRNAs), etc. Different types of methylation and ncRNAs mutually regulate and interact to form intricate networks to mediate precisely breast cancer genesis. In this review, we elaborate on the crosstalk between major methylation modifications and ncRNAs and discuss the role of their interaction in promoting breast cancer oncogenesis. This review can provide novel insights into establishing a new diagnostic marker system on methylation patterns of ncRNAs and therapeutic perspectives of combining ncRNA oligonucleotides and phytochemical drugs for breast cancer therapy.

Circulation microRNA expression profiles in patients with complete responses to chemoradiotherapy in nasopharyngeal carcinoma

Background

Aims

Methods

Results

Conclusion

Exosomes in bone remodeling and breast cancer bone metastasis

Exosomes are endosome-derived microvesicles that carry cell-specific biological cargo, such as proteins, lipids, and noncoding RNAs (ncRNAs). They play a key role in bone remodeling by enabling the maintenance of a balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Recent evidence indicates that exosomes disrupt bone remodeling that occurs during breast cancer (BC) progression. The bone is a preferred site for BC metastasis owing to its abundant osseous reserves. In this review, we aimed to highlight the roles of exosomes derived from bone cells and breast tumor in bone remodeling and BC bone metastasis (BCBM). We also briefly outline the mechanisms of action of ncRNAs and proteins carried by exosomes secreted by bone and BCBM. Furthermore, this review highlights the potential of utilizing exosomes as biomarkers or delivery vehicles for the diagnosis and treatment of BCBM.

LncRNA UCA1 promotes SOX12 expression in breast cancer by regulating m6A modification of miR-375 by METTL14 through DNA methylation

Breast cancer, a multifactorial disease, represents one of the leading causes of cancer-related morbidity and mortality in women. This study set out to elucidate the underlying mechanism by which lncRNA UCA1 affects the m⁶A modification of miR-375 by mediating the DNA methylation of METTL14 and then altering SOX12 expression in breast cancer. First, the expression patterns of lncRNA UCA1, miR-375, and apoptosis-related factors were quantitated by means of RT-qPCR and western blot analysis. In addition, the proliferation, invasion, and apoptosis of cells were detected using CCK-8, Transwell, and flow cytometry, respectively. RIP was performed to further uncover the interaction of lncRNA UCA1 and DNA methyltransferases, and MSP was employed for METTL14 promoter region methylation. The DNA methyltransferase enrichment in the METTL14 promoter region was measured by ChIP. The targeting relationship between miR-375 and SOX12 was confirmed by bioinformatics analysis and dual-luciferase report assay. Lastly, the aforementioned mechanism was also verified using tumor xenograft in vivo. It was found the elevated lncRNA UCA1 expression levels serve as a risk factor of poor prognosis in breast cancer. Meanwhile, silencing lncRNA UCA1 could inhibit the proliferation and invasion, but promote apoptosis of breast cancer cells by reducing the DNA methylation of METTL14 and augmenting its expression. Furthermore, METTL14 was observed to mediate the low miR-375 expression through m⁶A modification, leading to increased SOX12 expression levels in breast cancer. Altogether, findings obtained in our study indicated that silencing lncRNA UCA1 curbed the progression of breast cancer through the METTL14-miR-375-SOX12 axis.

Glutamine-Derived Aspartate Biosynthesis in Cancer Cells: Role of Mitochondrial Transporters and New Therapeutic Perspectives

Simple Summary

In recent years, aspartate has been increasingly acknowledged as a critical player in the metabolism of cancer cells which use this metabolite for nucleotide and protein synthesis and for redox homeostasis. Most intracellular aspartate derives from the mitochondrial catabolism of glutamine. To date at least four mitochondrial transporters have been involved in this metabolic pathway. Their involvement appears to be cancer type-specific and dependent on glutamine availability. Targeting these mitochondrial transporters may represent a new attractive strategy to fight cancer. The aim of this review is to dissect the role of each of these transporters in relation to the type of cancer and the availability of nutrients in the tumoral microenvironment.

Abstract

Aspartate has a central role in cancer cell metabolism. Aspartate cytosolic availability is crucial for protein and nucleotide biosynthesis as well as for redox homeostasis. Since tumor cells display poor aspartate uptake from the external environment, most of the cellular pool of aspartate derives from mitochondrial catabolism of glutamine. At least four transporters are involved in this metabolic pathway: the glutamine (SLC1A5_var), the aspartate/glutamate (AGC), the aspartate/phosphate (uncoupling protein 2, UCP2), and the glutamate (GC) carriers, the last three belonging to the mitochondrial carrier family (MCF). The loss of one of these transporters causes a paucity of cytosolic aspartate and an arrest of cell proliferation in many different cancer types. The aim of this review is to clarify why different cancers have varying dependencies on metabolite transporters to support cytosolic glutamine-derived aspartate availability. Dissecting the precise metabolic routes that glutamine undergoes in specific tumor types is of upmost importance as it promises to unveil the best metabolic target for therapeutic intervention.

SPOCD1 regulated by miR-133a-3p promotes hepatocellular carcinoma invasion and metastasis

Objective

To investigate the tumorigenic role of spen paralogue and orthologue C-terminal domain-containing 1 (SPOCD1) in hepatocellular carcinoma (HCC) and identify the upstream regulatory mechanism.

Methods

We analyzed SPOCD1 and miR-133-3p expression in normal and HCC tissues from the Cancer Genome Atlas and UALCAN databases, and in normal hepatocytes and HCC cell lines by real-time quantitative polymerase chain reaction and western blot. We identified the miR-133a-3p-binding site on the SPOCD1 3ʹ-untranslated region using TargetScan. Hierarchical regulation was confirmed by luciferase assay and miR-133a-3p overexpression/silencing. Cell proliferation, migration, invasion, and colony formation were assessed by MTT, scratch, transwell, and clonogenic assays, respectively.

Results

SPOCD1 was highly expressed in HCC tissues and cell lines, while miR-133a-3p expression was significantly downregulated. Kaplan–Meier analysis indicated that high SPOCD1 expression was significantly associated with poor survival. TargetScan and luciferase reporter assay revealed that SPOCD1 was the downstream target of miR-133a-3p. Overexpression of miR-133a-3p significantly inhibited the expression of SPOCD1, while miR-133a-3p knockdown significantly increased SPOCD1 expression.

Conclusion

SPOCD1, regulated by miR-133a-3p, promotes HCC cell proliferation, migration, invasion, and colony formation. This study provides the first evidence for the role of the miR-133a-3p/SPOCD1 axis in HCC tumorigenesis.

Preclinical Imaging Evaluation of miRNAs' Delivery and Effects in Breast Cancer Mouse Models: A Systematic Review

BACKGROUND

We have conducted a systematic review focusing on the advancements in preclinical molecular imaging to study the delivery and therapeutic efficacy of miRNAs in mouse models of breast cancer.

METHODS

A systematic review of English articles published in peer-reviewed journals using PubMed, EMBASE, BIOSIS™ and Scopus was performed. Search terms included breast cancer, mouse, mice, microRNA(s) and miRNA(s).

RESULTS

From a total of 2073 records, our final data extraction was from 114 manuscripts. The most frequently used murine genetic background was Balb/C (46.7%). The most frequently used model was the IV metastatic model (46.8%), which was obtained via intravenous injection (68.9%) in the tail vein. Bioluminescence was the most used frequently used tool (64%), and was used as a surrogate for tumor growth for efficacy treatment or for the evaluation of tumorigenicity in miRNA-transfected cells (29.9%); for tracking, evaluation of engraftment and for response to therapy in metastatic models (50.6%).

CONCLUSIONS

This review provides a systematic and focused analysis of all the information available and related to the imaging protocols with which to test miRNA therapy in an in vivo mice model of breast cancer, and has the purpose of providing an important tool to suggest the best preclinical imaging protocol based on available evidence.

DNMT1-induced miR-378a-3p silencing promotes angiogenesis via the NF-κB signaling pathway by targeting TRAF1 in hepatocellular carcinoma

BACKGROUND

Angiogenesis plays an important role in the occurrence, development and metastasis of hepatocellular carcinoma (HCC). According to previous studies, miR-378a participates in tumorigenesis and tumor metastasis, but its exact role in HCC angiogenesis remains poorly understood.

METHODS

qRT-PCR was used to investigate the expression of miR-378a-3p in HCC tissues and cell lines. The effects of miR-378a-3p on HCC in vitro and in vivo were examined by Cell Counting Kit-8 (CCK-8), Transwell, tube formation and Matrigel plug assays, RNA sequencing, bioinformatics, luciferase reporter, immunofluorescence and chromatin immunoprecipitation (ChIP) assays were used to detect the molecular mechanism by which miR-378a-3p inhibits angiogenesis.

RESULTS

We confirmed that miR-378a-3p expression was significantly downregulated and associated with higher microvascular density (MVD) in HCC; miR-378a-3p downregulation indicated a short survival time in HCC patients. miR-378a-3p knockdown led to a significant increase in angiogenesis in vitro and in vivo. We found that miR-378a-3p directly targeted TNF receptor associated factor 1 (TRAF1) to attenuate NF-κB signaling, and then downregulated secreted vascular endothelial growth factor. DNA methyltransferase 1 (DNMT1)-mediated hypermethylation of miR-378a-3p was responsible for downregulating miR-378a-3p. Moreover, a series of investigations indicated that p65 initiated a positive feedback loop that could upregulate DNMT1 to promote hypermethylation of the miR-378a-3p promoter.

CONCLUSION

Our study indicates a novel DNMT1/miR-378a-3p/TRAF1/NF-κB positive feedback loop in HCC cells, which may become a potential therapeutic target for HCC.

Regulatory roles of miRNAs 16, 133a, and 223 on osteoclastic bone destruction caused by breast cancer metastasis

Osteolytic bone metastasis leads to skeletal-related events, resulting in a decline in the patient activities and survival; therefore, it is important to understand the mechanism underlying bone metastasis. Recent studies have suggested that microRNAs (miRNAs or miRs) are involved in osteoclast differentiation and/or osteolytic bone metastasis; however, the roles of miRNAs have not been elucidated. In the present study, the roles of miRNAs in bone destruction caused by breast cancer metastasis were investigated in vitro and in vivo. miR-16, miR-133a and miR-223 were transfected into a human breast cancer cell line, MDA-MB-231. The expression of osteolytic factors in conditioned medium (miR-CM) collected from the culture of transfected cells was assessed. To evaluate the effects of miRNAs on osteoclast differentiation and activities, tartrate-resistant acid phosphatase (TRAP) staining and bone resorptive assays were performed in osteoclasts following miR-CM treatment. To create in vivo bone metastasis models for histological and morphometric evaluation, miRNA-transfected MDA-MB-231 cells were transplanted into the proximal tibia of nude mice. Expression of osteolytic factors, including receptor activator for nuclear factor-κB ligand (RANKL), interleukin (IL)-1β, IL-6, parathyroid hormone-related protein (PTHrP), and tumor necrosis factor (TNF), was increased in miR-16-CM, whereas it was decreased in both miR-133a-CM and miR-223-CM. TRAP staining and bone resorptive assays revealed that osteoclast function and activities were promoted by miR-16-CM treatment, whereas they were suppressed by miR-133a-CM and miR-223-CM. Consistent with in vitro findings, in vivo experiments revealed that the overexpression of miR-16 increased osteoclast activities and bone destruction in MDA-MB-231 cells, whereas the opposite results were observed in both miR-133a- and miR-223-transfected MDA-MB-231 cells. Our results indicated that miR-16 promoted osteoclast activities and bone destruction caused by breast cancer metastasis in the bone microenvironment, whereas miR-133a and miR-223 suppressed them. These miRNAs could be potential biomarkers and therapeutic targets for breast cancer bone metastasis.

LncRNA CTD-3252C9.4 modulates pancreatic cancer cell survival and apoptosis through regulating IFI6 transcription

BACKGROUND

Pancreatic cancer (PC) is one of the most lethal cancer types with high degree of malignancy and poor prognosis. Recent studies have shown that long non-coding RNAs (lncRNAs) were associated with the initiation and progression of pancreatic cancer. In the current study, we have investigated the expression, biological function and mechanism of a lncRNA CTD-3252C9.4 in pancreatic cancer.

METHODS

The expression of CTD-3252C9.4 in pancreatic cancer cells and tissues was measured by qRT-PCR. In vitro and in vivo functional experiments assays were implemented for identifying CTD-3252C9.4 function in pancreatic cancer. Molecular relationships among CTD-3252C9.4, IRF1 and IFI6 were investigated via luciferase reporter assay, pulldown assay and ChIP assays.

RESULTS

CTD-3252C9.4 was found remarkably decreased in pancreatic cancer cells and tissues. Overexpression of CTD-3252C9.4 suppressed migration, invasion and proliferation, yet facilitated apoptosis of pancreatic cancer cells both in vitro and in vivo. Then, IFI6 was identified as a downstream target that could be down-regulated by CTD-3252C9.4 and IFI6 overexpression could counteract the effects of CTD-3252C9.4 upregulation on the survival and apoptosis of pancreatic cancer cells. Furthermore, mechanism experiments revealed that IRF1 was a transcriptional factor of IFI6 that can be blocked by CTD-3252C9.4 to inhibit IFI6 transcription.

CONCLUSION

Our data indicated that CTD-3252C9.4 could promote pancreatic cancer cell apoptosis and restrain cell growth via binding IRF1 and preventing the transcription of IFI6, which may become a potential therapeutic target for pancreatic cancer.

Prognostic Implications of microRNA-155, -133a, -21 and -205 in Breast Cancer Patients' Plasma

BACKGROUND

Breast cancer, being a heterogenous disease at the intra-tumoral and intertumoral levels, presents challenges in following the progress of the disease. Tumour-secreted aberrantly expressed miRNAs obtained from peripheral blood represent a non-invasive alternative resource for detecting and monitoring the development of the disease. This study evaluates the expression of miR-155, miR-133a, miR-21 and miR-205 as non-invasive, prognostic and follow-up markers for breast cancer.

METHODS

Plasma expression levels of miR-155, miR-133a, miR-21 and miR-205 were measured using real-time PCR in breast cancer patients (n=63) at presentation, healthy controls (n=25), and in post-treatment samples of 31 patients. A meta-analysis was performed using 43 studies identified from PubMed, Google Scholar and Scopus databases. Hedge's g values were used to calculate the overall effect size.

RESULTS

Plasma miR-21 levels were higher in breast cancer patients at presentation compared to controls, while no difference was observed for miR-155, miR-133a and miR-205. These results were further supported by the meta-analysis. The altered levels of miR-155 during tamoxifen treatment indicated a potential role for miR-155 in monitoring treatment response. Further, high expressions of at least three miRNAs correlated with poor overall survival in the breast cancer patients.

CONCLUSION

Plasma levels of miR-155, miR-133a, miR-21 and miR-205 may be useful as prognostic and follow-up markers for breast cancer with further validation in a large cohort of patients.

MicroRNA-133a-3p inhibits cell proliferation, migration and invasion in colorectal cancer by targeting AQP1

Recently, miR-133a-3p has been identified as a marker for human colorectal cancer (CRC) and the association between miR-133a-3p and aquaporin 1 (AQP1) has been described in endothelial cells. However, the regulatory functions of the miR-133a-3p/AQP1 axis remain unclear in CRC. The present study analyzed the expression of miR-133a-3p and AQP1 in CRC tissues (n=56) and cell lines using reverse transcription-quantitative PCR and western blot analysis. The χ2 test was used to assess the associations between miR-133a-3p/AQP1 and clinicopathological features of patients with CRC. Next, the functional role of miR-133a-3p/AQP1 in CRC was evaluated in vitro by performing Cell Counting Kit-8 and Transwell assays. Moreover, the online software tool TargetScan7.1 was used to predict AQP1 as the target gene of miR-133a-3p, followed by validation using a luciferase reporter assay. The results showed that miR-133a-3p was significantly downregulated, while AQP1 was upregulated in CRC tissues and cell lines compared with corresponding controls. Clinically, it was demonstrated that miR-133a-3p/AQP1 expression was significantly associated with tumor TNM stage (P=0.020). Functional experiments indicated that miR-133a-3p-overexpression remarkably suppressed, while knockdown promoted, cell proliferation, migration and invasion in CRC cells. Mechanically, AQP1 was identified and validated as a target gene of miR-133a-3p in CRC cells. The expression level of AQP1 mRNA was not correlated with miR-133a-3p expression in CRC tissues. Furthermore, AQP1-knockdown induced, while overexpression reversed, the suppressive effects of miR-133a-3p on CRC cells. Taken together, these findings suggested that miR-133a-3p might be a tumor suppressor by suppressing cell proliferation, migration and invasion via targeting AQP1.

MiR-133a-3p inhibits the malignant progression of esophageal cancer by targeting CDCA8

OBJECTIVE

To explore the interaction between miR-133a-3p and CDCA8 in esophageal cancer (EC) and their effect on malignant behavior of EC cells.

METHODS

Differential miRNAs and mRNAs were obtained from The Cancer Genome Atlas (TCGA) database. Quantitative real-time PCR (qRT-PCR) was used to detect the expression levels of miR-133a-3p and CDCA8 mRNA in EC cells. Western blot was used to detect the expression of CDCA8 protein. CCK-8, flow cytometry, and Transwell assays were conducted to detect cell proliferation, cell cycle and apoptosis, as well as migration and invasion, respectively. The targeting relationship between miR-133a-3p and CDCA8 was verified by dual-luciferase reporter gene assay.

RESULTS

In EC, miR-133a-3p expression was evidently low and CDCA8 expression was prominently high. MiR-133a-3p down-regulated CDCA8 expression. A range of cell function experiments revealed that CDCA8 promoted the proliferation, migration and invasion of EC cells, reduced cell cycle arrest in G0/G1 phase and inhibited cell apoptosis, while miR-133a-3p could reverse the above effects by regulating CDCA8.

CONCLUSION

MiR-133a-3p is a crucial tumor suppressor miRNA in EC, playing a tumor suppressor role by targeting CDCA8.

MiR-133a-3p attenuates resistance of non-small cell lung cancer cells to gefitinib by targeting SPAG5

Background

Gefitinib is an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR‐TKI), clinically used to treat patients with non‐small cell lung cancer driven by EGFR mutations. Unfortunately, EGFR‐TKI resistance has become a clinical problem for the effective treatment of NSCLC patients. The purpose of this study was to explore the effect and mechanism of miR‐133a‐3p on the gefitinib sensitivity of NSCLC cells.

Methods

The gefitinib‐resistant PC9 (PC9/GR) cells were established through repeated long‐term exposure to gefitinib for half a year. Then, PC9/GR cells were transfected with miR‐133a‐3p mimics and PC9 cells were transfected with miR‐133a‐3p inhibitors to increase or decrease the expression of miR‐133a‐3p. CCK‐8 assay, colony formation assay, and caspase‐3 activity assay were employed to detect cell resistance to gefitinib. Quantitative real‐time PCR and Western blotting were used to evaluate the levels of miR‐133a‐3p, SPAG5, and other related genes. Starbase database was used to predict the target gene of miR‐133a‐3p and the prognosis of NSCLC patients. Target gene of miR‐133a‐3p was verified through dual‐luciferase reporter gene assay.

Results

MiR‐133a‐3p was significantly downregulated in gefitinib‐resistant cell line PC9/GR vs. gefitinib‐sensitive cell line PC9. Overexpression of miR‐133a‐3p increased the sensitivity of NSCLC cells to gefitinib and vice versa. Furthermore, SPAG5 is an important target gene of miR‐133a‐3p, and SPAG5 can reverse miR‐133a‐3p‐mediated gefitinib sensitivity of NSCLC cells.

Conclusions

These findings indicated that miR‐133a‐3p/SPAG5 axis played a vital role in acquired resistance to gefitinib in NSCLC cells, and miR‐133a‐3p may represent a potential therapeutic strategy for the treatment of human NSCLC.

MiR-206 promotes extracellular matrix accumulation and relieves infantile hemangioma through targeted inhibition of DNMT3A

MiR-206 is abnormally expressed in infant hemangioma endothelial cells (HemECs), but the mechanism is not clear. We explored the intervention of miR-206 in HemECs in relation to extracellular matrix (ECM) metabolism. We selected 48 cases of infantile hemangioma (IH) from volunteer organizations. After the isolated and extracted HemECs were interfered with overexpressed or silenced miR-206, the effects of miR-206 on the proliferation, migration and invasion of HemECs were examined through basic cell function experiments. The expression differences of miR-206, DNA Methyltransferase 3A (DNMT3A) and ECM-related genes were analyzed as needed by qRT-PCR or Western blot. TargetScan and dual-luciferase experiments were applied to predict and confirm the binding relationship between miR-206 and DNMT3A. The correlation between miR-206 and DNMT3A was analyzed in IH tissues by Pearson correlation coefficient, and further confirmed in HemECs by conducting rescue experiments. A nude mouse model of xenograft tumor was constructed to verify the results of in vitro experiments. MiR-206, which was downregulated in proliferative hemangioma, suppressed the malignant development of HemECs by regulating ECM-related genes. As the target gene of miR-206, DNMT3A was high-expressed in IH tissues and was negatively correlated with miR-206. Overexpressed DNMT3A counteracted the inhibitory effect of miR-206 mimic on HemECs and its regulatory effect on ECM. The results of in vivo experiments were consistent with those from cell experiments. Thus, miR-206 could promote ECM accumulation through targeted inhibition of DNMT3A, further inhibiting the malignant development of HemECs and relieving IH.

MicroRNA-133a-3p suppresses malignant behavior of non-small cell lung cancer cells by negatively regulating ERBB2

Non-small cell lung cancer (NSCLC) has high morbidity and mortality rates worldwide, and tumor metastasis is generally associated with poor prognosis. Chemotherapy resistance aggravates the challenges associated with treating NSCLC. Therefore, identifying effective targets and developing therapies based on these findings could bring novel perspectives for patients with metastatic NSCLC. The expression levels of receptor tyrosine-protein kinase erbB-2 (ERBB2) are associated with NSCLC progression. Differential microRNA (miR) expression profiles have been identified in tumors and can be used to identify multiple malignant phenotypes. miR-133a-3p expression is dysregulated in a variety of tumors. However, to the best of our knowledge, the association between miR-133a-3p and the NSCLC pathogenesis process has not been demonstrated yet. The present study revealed a decrease in miR-133a-3p expression in both tissues and cell lines, which was detected using reverse transcription-quantitative (RT-q)PCR, and western blotting and RT-qPCR demonstrated ERBB2 levels were increased at both protein and mRNA levels. Bioinformatics analysis and dual-luciferase reporter assays demonstrated that ERBB2 was a direct target of miR-133a-3p. Furthermore, MTT, wound healing and Transwell assays revealed that overexpression of miR-133a-3p suppressed proliferation, invasion and migration of NSCLC cells, respectively, effects that were inhibited following ERBB2 overexpression. In addition, immunofluorescence assays demonstrated that overexpression of ERBB2 upregulated N-cadherin expression, while E-cadherin expression was downregulated. In conclusion, the present data demonstrated that miR-133a-3p acted as a tumor suppressor by negatively regulating ERBB2 expression. The miR-133a-3p/ERBB2 axis may be a potential target for the diagnosis and treatment of NSCLC in the future.

Hypoxic glioma-derived exosomes promote M2-like macrophage polarization by enhancing autophagy induction

Exosomes participate in intercellular communication and glioma microenvironment modulation, but the exact mechanisms by which glioma-derived exosomes (GDEs) promote the generation of the immunosuppressive microenvironment are still unclear. Here, we investigated the effects of GDEs on autophagy, the polarization of tumor-associated macrophages (TAMs), and glioma progression. Compared with normoxic glioma-derived exosomes (N-GDEs), hypoxic glioma-derived exosomes (H-GDEs) markedly facilitated autophagy and M2-like macrophage polarization, which subsequently promoted glioma proliferation and migration in vitro and in vivo. Western blot and qRT-PCR analyses indicated that interleukin 6 (IL-6) and miR-155-3p were highly expressed in H-GDEs. Further experiments showed that IL-6 and miR-155-3p induced M2-like macrophage polarization via the IL-6-pSTAT3-miR-155-3p-autophagy-pSTAT3 positive feedback loop, which promotes glioma progression. Our study clarifies a mechanism by which hypoxia and glioma influence autophagy and M2-like macrophage polarization via exosomes, which could advance the formation of the immunosuppressive microenvironment. Our findings suggest that IL-6 and miR-155-3p may be novel biomarkers for diagnosing glioma and that treatments targeting autophagy and the STAT3 pathway may contribute to antitumor immunotherapy.

MicroRNA: A signature for cancer progression

MicroRNAs (miRNAs) are a group of small non-coding RNAs that post-transcriptionally control expression of genes by targeting mRNAs. miRNA alterations partake in the establishment and progression of different types of human cancer. Consequently, expression profiling of miRNA in human cancers has correlations with cancer detection, staging, progression, and response to therapies. Particularly, amplification, deletion, abnormal pattern of epigenetic factors and the transcriptional factors that mediate regulation of primary miRNA frequently change the landscape of miRNA expression in cancer. Indeed, changes in the quantity and quality of miRNAs are associated with the initiation of cancer, its progression and metastasis. Additionally, miRNA profiling has been used to categorize genes that can affect oncogenic pathways in cancer. Here, we discuss several circulating miRNA signatures, their expression profiles in different types of cancer and their impacts on cellular processes.

KDM5C Expedites Lung Cancer Growth and Metastasis Through Epigenetic Regulation of MicroRNA-133a

Background

KDM5C, a histone H3K4-specific demethylase, possess various biological functions in development of cancers. However, its relation to the microRNA (miRNA) regulation in lung cancer remains unknown. This study aims to study the regulatory role of KDM5C on modification of miR-133a in the progression of lung cancer.

Methods

Differentially expressed miRNAs were filtered from 34 paired lung cancer and paracancerous tissues. The correlation between miR-133a expression and the prognosis of lung cancer patients was determined by a bioinformatics website. Furthermore, malignant aggressiveness of lung cancer cells was detected after miR-133a upregulation by CCK-8, flow cytometry, and Transwell assays and in vivo tumorigenesis and metastasis experiments. Subsequently, we analyzed mRNA downregulated in cells overexpressing miR-133a using m microarray analysis and expounded the upstream regulatory mechanism of miR-133a using bioinformatics website prediction and functional validation.

Results

miR-133a was reduced in lung cancer tissues, and patients with low expression of miR-133a have worse survival rates. miR-133a restoration curtailed growth and metastasis of lung cancer cells in vitro and in vivo. Moreover, miR-133a downregulated PTBP1 expression, whereas overexpression of PTBP1 attenuated the suppressive effect of miR-133a on lung cancer cell aggressiveness. The level of methylation modification of miR-133a was reduced in lung cancer cells. KDM5C inhibited the expression of miR-133a by promoting the demethylation modification of its promoter histone.

Conclusion

Histone demethylase KDM5C inhibits the expression of miR-133a by elevating the demethylation modification of the promoter histone of miR-133a, thereby promoting the expression of PTBP1, which finally accelerates lung cancer cell growth and metastasis.

[Ginsenoside 20(S)-Rg3 upregulates tumor suppressor VHL gene expression by suppressing DNMT3A-mediated promoter methylation in ovarian cancer cells]

OBJECTIVE

To explore the mechanism by which ginsenoside 20(S)-Rg3 upregulates the expression of tumor suppressor von Hippel-Lindau (VHL) gene in ovarian cancer cells.

METHODS

Ovarian cancer cell line SKOV3 treated with 20(S)-Rg3 were examined for mRNA and protein levels of VHL, DNMT1, DNMT3A and DNMT3B by real-time PCR and Western blotting, respectively. The changes in VHL mRNA expression in SKOV3 cells in response to treatment with 5-Aza-CdR, a DNA methyltransferase inhibitor, were detected using real-time PCR. VHL gene promoter methylation was examined with methylation-specific PCR and VHL expression levels were determined with real-time PCR and Western blotting in non-treated or 20(S)-Rg3-treated SKOV3 cells and in 20(S)-Rg3-treated DNMT3A-overexpressing SKOV3 cells. VHL and DNMT3A protein levels were detected by immunohistochemistry in subcutaneous SKOV3 cell xenografts in nude mice.

RESULTS

Treatment of SKOV3 cells with 20(S)-Rg3 significantly upregulated VHL and downregulated DNMT3A expressions at both the mRNA and protein levels (P < 0.05) and upregulated DNMT3B expression only at the mRNA level, but did not cause significant changes in either the mRNA or protein level of DNMT1. Treatment of the cells with 2 and 5 μmol/L 5-Aza-CdR obviously increased VHL mRNA expression by by over 3 folds (P < 0.05). 20(S)-Rg3 significantly decreased the methylation level in the promoter region of VHL gene, and this effect was abrogated by DNMT3A overexpression in the cells (P < 0.05). Immunohistochemisty showed a significantly increased VHL expression but a lowered DNMT3A expression in subcutaneous SKOV3 cell xenografts in 20 (S)-Rg3-treated nude mice.

CONCLUSIONS

Ginsenoside 20(S)-Rg3 upregulates VHL expression in ovarian cancer cells by suppressing DNMT3A-mediated DNA methylation.

Emerging roles of MiR-133a in human cancers

MicroRNAs (miRNAs) can post-transcriptionally regulate the expression of cancer-relevant genes via binding to the 3'-untranslated region (3'-UTR) of the target mRNAs. MiR-133a, as a miRNA, participate in tumorigenesis, progression, autophagy and drug-resistance in various malignancies. Based on the recent insights, we discuss the functions of miR-133a in physiological and pathological processes and its potential effects on cancer diagnosis, prognosis and therapy.

A Dynamic Role of Mastermind-Like 1: A Journey Through the Main (Path)ways Between Development and Cancer

Major signaling pathways, such as Notch, Hedgehog (Hh), Wnt/β-catenin and Hippo, are targeted by a plethora of physiological and pathological stimuli, ultimately resulting in the modulation of genes that act coordinately to establish specific biological processes. Many biological programs are strictly controlled by the assembly of multiprotein complexes into the nucleus, where a regulated recruitment of specific transcription factors and coactivators on gene promoter region leads to different transcriptional outcomes. MAML1 results to be a versatile coactivator, able to set up synergistic interlinking with pivotal signaling cascades and able to coordinate the network of cross-talking pathways. Accordingly, despite its original identification as a component of the Notch signaling pathway, several recent reports suggest a more articulated role for MAML1 protein, showing that it is able to sustain/empower Wnt/β-catenin, Hh and Hippo pathways, in a Notch-independent manner. For this reason, MAML1 may be associated to a molecular “switch”, with the function to control the activation of major signaling pathways, triggering in this way critical biological processes during embryonic and post-natal life. In this review, we summarize the current knowledge about the pleiotropic role played by MAML proteins, in particular MAML1, and we recapitulate how it takes part actively in physiological and pathological signaling networks. On this point, we also discuss the contribution of MAML proteins to malignant transformation. Accordingly, genetic alterations or impaired expression of MAML proteins may lead to a deregulated crosstalk among the pathways, culminating in a series of pathological disorders, including cancer development. Given their central role, a better knowledge of the molecular mechanisms that regulate the interplay of MAML proteins with several signaling pathways involved in tumorigenesis may open up novel opportunities for an attractive molecular targeted anticancer therapy.

Epigenetic and breast cancer therapy: Promising diagnostic and therapeutic applications

The global burden of breast cancer (BC) is increasing significantly. This trend is caused by several factors such as late diagnosis, limited treatment options for certain BC subtypes, drug resistance which all lead to poor clinical outcomes. Recent research has reported the role of epigenetic alterations in the mechanism of BC pathogenesis and its hallmarks include drug resistance and stemness features. The understanding of these modifications and their significance in the management of BC carcinogenesis is challenging and requires further attention. Nevertheless, it promises to provide novel insight needed for utilizing these alterations as potential diagnostic, prognostic markers, predict treatment efficacy, as well as therapeutic agents. This highlights the importance of continuing research development to further advance the existing knowledge on epigenetics and BC carcinogenesis to overcome the current challenges. Hence, this review aims to shed light and discuss the current state of epigenetics research in the diagnosis and management of BC.

Expression and prognosis analysis of DNMT family in acute myeloid leukemia

DNA methyltransferases (DNMTs) by regulating DNA methylation play crucial roles in the progression of hematologic malignancies, especially for acute myeloid leukemia (AML). Accumulating investigations have identified the high incidence of DNMT3A mutation in AML, and it is correlated with poor prognosis. Although a few studies have shown the expression of DNMTs and their clinical significance in AML, the results remain to be discussed. Herein, we systemically analyzed the DNMTs expression and their relationship with clinic-pathological features and prognosis in AML patients. DNMTs expression especially for DNMT3A/3B was closely associated with AML among various human cancers. DNMT3A expression was increased in AML patients, whereas DNMT3B expression was decreased. Significant associations between DNMT3A/B expression and clinic-pathological features/gene mutations were observed. Kaplan-Meier analysis showed that DNMT3A expression was associated with better overall survival (OS) and leukemia-free survival (LFS) among whole-cohort AML, and independently affected OS determined by Cox repression multivariate analysis. Notably, patients that received hematopoietic stem cell transplantation (HSCT) showed significantly better OS and LFS in DNMT3A lower-expressed groups, whereas patients in DNMT3A higher-expressed groups did not. By bioinformatics analysis, DNMT3A expression was found to be positively correlated with several leukemia-associated genes/microRNAs, and DNMT3A was identified as direct targets of miR-429 and miR-29b in AML. Collectively, our study demonstrated that DNMT3A/3B showed significant expression differences in AML. DNMT3A expression acted as a potential prognostic biomarker and may guide treatment choice between chemotherapy and HSCT in AML.

Role of cancer stem cells in the development of giant cell tumor of bone

The primary bone tumor is usually observed in adolescence age group which has been shown to be part of nearly 20% of the sarcomas known today. Giant cell tumor of bone (GCTB) can be benign as well as malignant tumor which exhibits localized dynamism and is usually associated with the end point of a long bone. Giant cell tumor (GCT) involves mononuclear stromal cells which proliferate at a high rate, multinucleated giant cells and stromal cells are equally present in this type of tumor. Cancer stem cells (CSCs) have been confirmed to play a potential role in the development of GCT. Cancer stem cell-based microRNAs have been shown to contribute to a greater extent in giant cell tumor of bone. CSCs and microRNAs present in the tumors specifically are a great concern today which need in-depth knowledge as well as advanced techniques to treat the bone cancer effectively. In this review, we attempted to summarize the role played by cancer stem cells involving certain important molecules/factors such as; Mesenchymal Stem Cells (MSCs), miRNAs and signaling mechanism such as; mTOR/PI3K-AKT, towards the formation of giant cell tumor of bone, in order to get an insight regarding various effective strategies and research advancements to obtain adequate knowledge related to CSCs which may help to focus on highly effective treatment procedures for bone tumors.

Identification of the key genes and microRNAs in adult acute myeloid leukemia with FLT3 mutation by bioinformatics analysis

Background: Associated with poor prognosis, FMS-like tyrosine kinase 3 (FLT3) mutation appeared frequently in acute myeloid leukemia (AML). Herein, we aimed to identify the key genes and miRNAs involved in adult AML with FLT3 mutation and find possible therapeutic targets for improving treatment. Materials: Gene and miRNA expression data and survival profiles were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database. EdgeR of R platform was applied to identify the differentially expressed genes and miRNAs (DEGs, DE-miRNAs). Gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed by Metascape and DAVID. And protein-protein interaction network, miRNA-mRNA regulatory network and clustering modules analyses were performed by STRING database and Cytoscape software. Results: Survival analysis showed FLT3 mutation led to adverse outcome in AML. 24 DE-miRNAs (6 upregulated, 18 downregulated) and 250 DEGs (54 upregulated, 196 downregulated) were identified. Five miRNAs had prognostic value and the results matched their expression levels (miR-1-3p, miR-10a-3p, miR-10a-5p, miR-133a-3p and miR-99b-5p). GO analysis showed DEGs were enriched in skeletal system development, blood vessel development, cartilage development, tissue morphogenesis, cartilage morphogenesis, cell morphogenesis involved in differentiation, response to growth factor, cell-substrate adhesion and so on. The KEGG analysis showed DEGs were enriched in PI3K-Akt signaling pathway, ECM-receptor interaction and focal adhesion. Seven genes (LAMC1, COL3A1, APOB, COL1A2, APP, SPP1 and FSTL1) were simultaneously identified by hub gene analysis and module analysis. SLC14A1, ARHGAP5 and PIK3CA, the target genes of miR-10a-3p, resulted in poor prognosis. Conclusion: Our study successfully identified molecular markers, processes and pathways affected by FLT3 mutation in AML. Furthermore, miR-10a-3p, a novel oncogene, might involve in the development of FLT3 mutation adult AML by targeting SLC14A1, ARHGAP5 and PIK3CA.