miR-519d-mediated downregulation of STAT3 suppresses breast cancer progression

MicroRNA dynamics, PTEN/PI3K/AKT signaling, and their relationship to breast cancer: prospects for pharmaceuticals and natural product application

BACKGROUND

Globally, Breast Cancer (BC) is the most frequent cancer in women and has a major negative impact on the physical and emotional well-being of its patients as well as one of the most common cancers to be diagnosed. Numerous studies have been published to identify various molecular pathways, including PI3K/AKT/PTEN. Moreover, growing evidence suggests that miRNAs have been found to play a vital role in the growth and carcinogenesis of tumors. Because of their crucial in the development and course of the illness, all other molecular variables, molecular pathways and microRNAs have gained recognition as important therapeutic targets in BC due to growing interest among researchers in utilizing synthetic drugs and natural products to target these signaling pathway with encouraging outcomes in vivo, in vitro and preclinical trials in recent years.

METHODS

We searched PUBMED, Science Direct, google scholar, Embase and Scopus for article published from the inception of each database to May 30, 2024.

RESULTS

We discussed PI3K/PTEN/AKT signaling pathway and microRNA activities with breast cancer cell line. In addition, this review covered a wide range of potential drug and natural products as targeted therapies that are linked to downregulating ER-α expression and activity, inhibiting proliferation, migration, metastasis and angiogenesis, inducing apoptosis, cell cycle arrest and sensitizing breast cancer cells. Many studies have been conducted, but as of right now, there are not enough articles to fully explain the treatment and research of breast cancer.

CONCLUSIONS

We also need more and more studies on breast cancer from a variety of perspectives. Future scientist will find it easier to consider breast cancer treatment after reading this article presentation. So, the review focuses on our understanding of the roles that microRNA and PI3/PTEN/AKT signaling pathways play in regulating BC. Furthermore, we emphasized the potential therapeutic benefits of newly discovered inhibitors and the use of natural compounds in alone or combinations during preclinical trials.

Unraveling the Potential of miRNAs from CSCs as an Emerging Clinical Tool for Breast Cancer Diagnosis and Prognosis

Breast cancer (BC) is the most diagnosed cancer in women and the second most common cancer globally. Significant advances in BC research have led to improved early detection and effective therapies. One of the key challenges in BC is the presence of BC stem cells (BCSCs). This small subpopulation within the tumor possesses unique characteristics, including tumor-initiating capabilities, contributes to treatment resistance, and plays a role in cancer recurrence and metastasis. In recent years, microRNAs (miRNAs) have emerged as potential regulators of BCSCs, which can modulate gene expression and influence cellular processes like BCSCs' self-renewal, differentiation, and tumor-promoting pathways. Understanding the miRNA signatures of BCSCs holds great promise for improving BC diagnosis and prognosis. By targeting BCSCs and their associated miRNAs, researchers aim to develop more effective and personalized treatment strategies that may offer better outcomes for BC patients, minimizing tumor recurrence and metastasis. In conclusion, the investigation of miRNAs as regulators of BCSCs opens new directions for advancing BC research through the use of bioinformatics and the development of innovative therapeutic approaches. This review summarizes the most recent and innovative studies and clinical trials on the role of BCSCs miRNAs as potential tools for early diagnosis, prognosis, and resistance.

Machine learning multi-omics analysis reveals cancer driver dysregulation in pan-cancer cell lines compared to primary tumors

Cancer cell lines have been widely used for decades to study biological processes driving cancer development, and to identify biomarkers of response to therapeutic agents. Advances in genomic sequencing have made possible large-scale genomic characterizations of collections of cancer cell lines and primary tumors, such as the Cancer Cell Line Encyclopedia (CCLE) and The Cancer Genome Atlas (TCGA). These studies allow for the first time a comprehensive evaluation of the comparability of cancer cell lines and primary tumors on the genomic and proteomic level. Here we employ bulk mRNA and micro-RNA sequencing data from thousands of samples in CCLE and TCGA, and proteomic data from partner studies in the MD Anderson Cell Line Project (MCLP) and The Cancer Proteome Atlas (TCPA), to characterize the extent to which cancer cell lines recapitulate tumors. We identify dysregulation of a long non-coding RNA and microRNA regulatory network in cancer cell lines, associated with differential expression between cell lines and primary tumors in four key cancer driver pathways: KRAS signaling, NFKB signaling, IL2/STAT5 signaling and TP53 signaling. Our results emphasize the necessity for careful interpretation of cancer cell line experiments, particularly with respect to therapeutic treatments targeting these important cancer pathways.

The Role of Cluster C19MC in Pre-Eclampsia Development

Pre-eclampsia is a placenta-related complication occurring in 2-10% of all pregnancies. miRNAs are a group of non-coding RNAs regulating gene expression. There is evidence that C19MC miRNAs are involved in the development of the placenta. Deregulation of chromosome 19 microRNA cluster (C19MC) miRNAs expression leads to impaired cell differentiation, abnormal trophoblast invasion and pathological angiogenesis, which can lead to the development of pre-eclampsia. Information was obtained through a review of articles available in PubMed Medline. Articles on the role of the C19MC miRNA in the development of pre-eclampsia published in 2009-2022 were analyzed. This review article summarizes the current data on the role of the C19MC miRNA in the development of pre-eclampsia. They indicate a significant increase in the expression of most C19MC miRNAs in placental tissue and a high level of circulating fractions in serum and plasma, both in the first and/or third trimester in women with PE. Only for miR-525-5p, low levels of plasma expression were noted in the first trimester, and in the placenta in the third trimester. The search for molecular factors indicating the development of pre-eclampsia before the onset of clinical symptoms seems to be a promising diagnostic route. Identifying women at risk of developing pre-eclampsia at the pre-symptomatic stage would avoid serious complications in both mothers and fetuses. We believe that miRNAs belonging to cluster C19MC could be promising biomarkers of pre-eclampsia development.

STAT family of transcription factors in breast cancer: Pathogenesis and therapeutic opportunities and challenges

Breast cancer is the most commonly diagnosed cancer and second-leading cause of cancer deaths in women. Breast cancer stem cells (BCSCs) promote metastasis and therapeutic resistance contributing to tumor relapse. Through activating genes important for BCSCs, transcription factors contribute to breast cancer metastasis and therapeutic resistance, including the signal transducer and activator of transcription (STAT) family of transcription factors. The STAT family consists of six major isoforms, STAT1, STAT2, STAT3, STAT4, STAT5, and STAT6. Canonical STAT signaling is activated by the binding of an extracellular ligand to a cell-surface receptor followed by STAT phosphorylation, leading to STAT nuclear translocation and transactivation of target genes. It is important to note that STAT transcription factors exhibit diverse effects in breast cancer; some are either pro- or anti-tumorigenic while others maintain dual, context-dependent roles. Among the STAT transcription factors, STAT3 is the most widely studied STAT protein in breast cancer for its critical roles in promoting BCSCs, breast cancer cell proliferation, invasion, angiogenesis, metastasis, and immune evasion. Consequently, there have been substantial efforts in developing cancer therapeutics to target breast cancer with dysregulated STAT3 signaling. In this comprehensive review, we will summarize the diverse roles that each STAT family member plays in breast cancer pathobiology, as well as, the opportunities and challenges in pharmacologically targeting STAT proteins and their upstream activators in the context of breast cancer treatment.

Signaling pathways modulated by miRNAs in breast cancer angiogenesis and new therapeutics

MicroRNAs (miRNAs) act as oncogenes or tumor suppressors by suppressing the expression of target genes, some of which are engaged in angiogenic signaling pathways directly or indirectly. Tumor development and metastasis are dependent on angiogenesis, and it is the main reason for the poor prognosis of cancer patients. New blood vessels are formed from pre-existing vessels when angiogenesis occurs. Thus, it is essential to develop primary tumors and the spread of cancer to surrounding tissues. MicroRNAs (miRNAs) are small noncoding RNAs involved in various biological processes. They can bind to the 3'-UTR of their target genes and prevent them from expressing. MiRNAs control the activity of endothelial cells (ECs) through altering many biological pathways, which plays a key role in cancer progression and angiogenesis. Recent findings revealed that tumor-derived extracellular vesicles participated directly in the control of tumor angiogenesis by delivering miRNAs to ECs. miRNAs recently show great promise in cancer therapies to inhibit angiogenesis. In this study, we showed the miRNA-regulated signaling pathways in tumor angiogenesis with highlighting the anti-angiogenic therapy response and miRNA delivery methods that have been used to inhibit angiogenesis in both in vivo and in vitro studies.

New stem cell autophagy surrogate diagnostic biomarkers in early-stage hepatocellular carcinoma in Egypt: A pilot study

BACKGROUND

Stem cell autophagy disruption is responsible for the development of hepatocellular carcinoma (HCC). Many non-coding RNAs are linked to the activation and inhibition of certain genes. The SQSTM1 gene controls stem cell autophagy as shown in previous studies. The upregulation of SQSTM1 is associated with the inhibition of autophagy in cancerous stem cells in patients with HCC.

AIM

To determine whether serum microRNA, hsa-miR-519d, is linked to SQSTM1 gene and whether they could be used as diagnostic biomarkers for early-stage HCC.

METHODS

In silico analysis was performed to determine the most correlated genes of autophagy with microRNAs. SQSTM1 and hsa-miR-519d were validated through this pilot clinical study. This study included 50 Egyptian participants, who were classified into three subgroups: Group 1 included 34 patients with early-stage HCC, Group 2 included 11 patients with chronic liver disease, and Group 3 (control) included 5 healthy subjects. All patients were subjected to full laboratory investigations, including viral markers and alpha-fetoprotein (AFP), abdominal ultrasound, and clinical assessment with the Child-Pugh score calculation. Besides, the patients with HCC underwent triphasic computed tomography with contrast to diagnose and determine the tumor site, size, and number. Quantitative real-time polymerase chain reaction was used to assess hsa-miR-519d-3p and SQSTM1 in the serum of all the study participants.

RESULTS

Hsa-miR-519d-3p was significantly upregulated in patients with HCC compared with those with chronic liver disease and healthy subjects with an area under the curve (AUC) of 0.939, with cutoff value 8.34, sensitivity of 91.2%, and specificity of 81.8%. SQSTM1 was upregulated with an AUC of 0.995, with cutoff value 7.89, sensitivity of 97.1%, and specificity of 100%. AFP significantly increased in patients with HCC with an AUC of 0.794, with cutoff value 7.30 ng/mL, sensitivity of 76.5%, and specificity of 72.7%.

CONCLUSION

This study is the first to show a direct relation between SQSTM1 and hsa-miR-519d-3p; they are both upregulated in HCC. Thus, they could be used as surrogate diagnostic markers for stem cell autophagy disturbance in early-stage HCC.

MicroRNA Regulation of Breast Cancer Stemness

Recent advances in our understanding of breast cancer have demonstrated that cancer stem-like cells (CSCs, also known as tumor-initiating cell (TICs)) are central for progression and recurrence. CSCs are a small subpopulation of cells present in breast tumors that contribute to growth, metastasis, therapy resistance, and recurrence, leading to poor clinical outcome. Data have shown that cancer cells can gain characteristics of CSCs, or stemness, through alterations in key signaling pathways. The dysregulation of miRNA expression and signaling have been well-documented in cancer, and recent studies have shown that miRNAs are associated with breast cancer initiation, progression, and recurrence through regulating CSC characteristics. More specifically, miRNAs directly target central signaling nodes within pathways that can drive the formation, maintenance, and even inhibition of the CSC population. This review aims to summarize these research findings specifically in the context of breast cancer. This review also discusses miRNAs as biomarkers and promising clinical therapeutics, and presents a comprehensive summary of currently validated targets involved in CSC-specific signaling pathways in breast cancer.

Regulation of breast cancer metastasis signaling by miRNAs

Despite the decline in death rate from breast cancer and recent advances in targeted therapies and combinations for the treatment of metastatic disease, metastatic breast cancer remains the second leading cause of cancer-associated death in U.S. women. The invasion-metastasis cascade involves a number of steps and multitudes of proteins and signaling molecules. The pathways include invasion, intravasation, circulation, extravasation, infiltration into a distant site to form a metastatic niche, and micrometastasis formation in a new environment. Each of these processes is regulated by changes in gene expression. Noncoding RNAs including microRNAs (miRNAs) are involved in breast cancer tumorigenesis, progression, and metastasis by post-transcriptional regulation of target gene expression. miRNAs can stimulate oncogenesis (oncomiRs), inhibit tumor growth (tumor suppressors or miRsupps), and regulate gene targets in metastasis (metastamiRs). The goal of this review is to summarize some of the key miRNAs that regulate genes and pathways involved in metastatic breast cancer with an emphasis on estrogen receptor α (ERα+) breast cancer. We reviewed the identity, regulation, human breast tumor expression, and reported prognostic significance of miRNAs that have been documented to directly target key genes in pathways, including epithelial-to-mesenchymal transition (EMT) contributing to the metastatic cascade. We critically evaluated the evidence for metastamiRs and their targets and miRNA regulation of metastasis suppressor genes in breast cancer progression and metastasis. It is clear that our understanding of miRNA regulation of targets in metastasis is incomplete.

MiR-519d and miR-328-3p Combinatorially Suppress Breast Cancer Progression

Background

MiR-519d and miR-328-3p had tumor-regulatory properties in different cancers, but their combinatorial effects and potential common target in breast cancer had not been fully reported. This research targeted to study the underlying mechanism of how miR-519d and miR-328-3p cooperatively suppressed breast cancer.

Methods

MiR-519d and miR-328-3p expressions in breast cancer tissues and cells were assessed and Ki-67 expression was also checked. DLR assay was executed to verify whether Ki-67 was a common target of miR-519d and miR-328-3p. Western blot, flow cytometry, colony formation, wound healing and transwell assays were applied to examine the inhibitory roles of these two miRNAs on the malignant behaviors of breast cancer cells and the potential molecular mechanism.

Results

Impeded miR-519d and miR-328-3p expressions and enhanced Ki-67 expression were detected in breast cancer tissues and cells. Ki-67 was confirmed as a target of these two miRNAs. MiR-519d and miR-328-3p hampered cell proliferation and blocked cell cycle via binding to Ki-67 and they also suppressed migration and invasion. The combinatorial effects of two miRNAs were much stronger than a single miRNA.

Conclusion

Our findings proved that miR-519d and miR-328-3p played combinatorial anti-cancer roles in breast cancer by directly targeting a common target Ki-67. Our study suggested that these two miRNAs might own the potential to become novel therapeutic biomarkers involved in the diagnosis and therapy of breast cancer.

Effects of microRNA regulation on antiangiogenic therapy resistance in non-small cell lung cancer

Antiangiogenic drugs have become a standard therapeutic regimen for advanced non-small cell lung cancer (NSCLC); however, many issues remain to be solved. Identifying specific markers to predict patient response to antiangiogenic drugs to ensure therapeutic efficacy would increase their clinical benefit. MicroRNAs (miRNAs) are involved in the process of resistance to antiangiogenic therapy, as they regulate various key signaling pathways. Therefore, miRNAs may be used as targets for reversing tumor resistance to antiangiogenic therapy. This article reviews the molecular mechanisms of antiangiogenic therapy resistance and the specific mechanisms of miRNA regulation of resistance. Signal transducer and activator of transcription 3 (STAT3) is one of multiple target genes of miRNAs, and is closely related to antiangiogenic research. Thus, it is described separately in this review article.

Dysregulation of microRNA in cholangiocarcinoma identified through a meta-analysis of microRNA profiling

BACKGROUND

In the past decades, the potential of microRNA (miRNA) in cancer diagnostics and prognostics has gained a lot of interests. In this study, a meta-analysis was conducted upon the pooled miRNA microarray data of cholangiocarcinoma (CCA).

AIM

To identify differentially expressed (DE) miRNAs and perform functional analyses in order to gain insights to understanding miRNA-target interactions involved in tumorigenesis pathways of CCA.

METHODS

Raw data from 8 CCA miRNA microarray datasets, consisting of 443 samples in total, were integrated and statistically analyzed to identify DE miRNAs via comparison of levels of miRNA expression between CCA and normal bile duct samples using t-tests (P < 0.001). The 10-fold cross validation was performed in order to increase the robustness of the t-test results.

RESULTS

Our data showed 70 up-regulated and 48 down-regulated miRNAs in CCA. Gene Ontology and pathway enrichment analyses revealed that mRNA targets of DE miRNAs were significantly involved in several biological processes. The most prominent dysregulated pathways included phosphatidylinositol-3 kinases/Akt, mitogen-activated protein kinase and Ras signaling pathways.

CONCLUSION

DE miRNAs found in our meta-analysis revealed dysregulation in major cancer pathways involved in the development of CCA. These results indicated the necessity of understanding the miRNA-target interactions and the significance of dysregulated miRNAs in terms of diagnostics and prognostics of cancers.

microRNA-519d Induces Autophagy and Apoptosis of Human Hepatocellular Carcinoma Cells Through Activation of the AMPK Signaling Pathway via Rab10

Background and Aim

Hepatocellular carcinoma (HCC) is a type of cancer with high mortality rates. The overexpression of microRNA-519d (miR-519d) has been explored in different types of cancers, which could significantly help suppress cancer development. This study aimed to investigate the interaction of miR-519d with its target gene, Rab10, as well as its effects on cell proliferation and autophagy in HCC cells through modulation of the AMPK signaling pathway.

Methods

Microarray analysis was used to analyze the differentially expressed genes in HCC, and the target genes of the screened-out miRNA were predicted and verified. The expression of miR-519d and Rab10, AMPK signaling pathway-related proteins, apoptosis- and autophagy-related proteins was determined by RT-qPCR and Western blot analysis in HCC tissues and cell lines. Lastly, the effects of miR-519d and Rab10 in HCC cell proliferation, apoptosis, and mouse tumour xenograft in vivo were examined through gain- and loss-of-function experiments.

Results

MiR-519d was down-regulated and Rab10 was upregulated in HCC tissues and cell lines. Overexpression of miR-519d decreased the expression of Rab10, mTOR, and Bcl-2, but increased the expression of Bax, Beclin1, Atg5, and p53. Upregulated miR-519d and downregulated Rab10 expression suppressed cell proliferation and induced cell apoptosis and autophagy in HCC cells. Finally, upregulation of miR-519d inhibited tumour growth in vivo.

Conclusion

The result obtained in this study indicates that up-regulation of miR-519d inhibits proliferation and promotes apoptosis and autophagy of HCC cells through activation of the AMPK signaling pathway via downregulating Rab10, which provides a potential target for the treatment of HCC.

Inhibition of TRIM32 Induced by miR-519d Increases the Sensitivity of Colorectal Cancer Cells to Cisplatin

BACKGROUND

Colorectal cancer is a leading cause of cancer-related death in the world. Despite cisplatin is a commonly used chemotherapeutic drug for the colorectal cancer treatment, resistance of cancer cells to cisplatin restricts its clinical efficacy. It is important to explore the potential mechanisms and take strategies to sensitize colorectal cancer cells to cisplatin treatment.

METHODS

Differences of TRIM32 and miR-519d expression between colorectal cancer cells and human normal colon epithelial cells were evaluated by qRT-PCR and Western blot assays. Cytotoxicity of cisplatin against colorectal cancer cells was tested by CCK-8 assay. Generation of reactive oxygen species (ROS), mitochondrial membrane potential and apoptosis was measured by flow cytometry. Dual-luciferase reporter assay was used to validate the association between miR-519d and TRIM32.

RESULTS

Significant increase of TRIM32 expression in colorectal cancer tissues and cell lines was observed. TRIM32 negatively regulated the cisplatin sensitivity in colorectal cancer cells. Mechanically, overexpression of TRIM32 was induced by decrease of miR-519d. Exogenous miR-519d can inhibit the expression of TRIM32 and thus promoted the cisplatin-induced apoptosis through the mitochondrial pathway.

CONCLUSION

Overexpression of TRIM32 was induced by the absence of miR-519d in colorectal cancer. MiR-519d can be used as a sensitizer during the cisplatin-based chemotherapy of colorectal cancer.

MiR-223-3p targeting epithelial cell transforming sequence 2 oncogene inhibits the activity, apoptosis, invasion and migration of MDA-MB-468 breast cancer cells

Purpose

This research was to investigate the role of miR-223-3p targeting epithelial cell transforming sequence 2 oncogene (ECT2) in activity, apoptosis, invasion and migration of MDA-MB-468 breast cancer (BC) cells.

Methods

The human BC cell lines MDA-MB-468 were used for the experiment. They were divided into six groups: blank group (no plasmid transfection), NC group (negative control, transfected empty plasmid), miR-223-3p mimic group (transfected miR-223-3p mimic plasmid), miR-223-3p inhibitor group (transfected miR-223-3p inhibitor plasmid), si-ECT2 group (transfected si ECT2 plasmid) and miR-223-3p mimic+oe-ECT2 group (transfected with miR-223-3p mimic plasmid and ECT2 plasmid).

Results

Compared with the NC group, the mRNA and protein expression of Bax in miR-223-3p mimic and si-ECT2 groups were significantly increased, while the mRNA and protein expression of ECT2, Bcl-2, vascular endothelial growth factor (VEGF), and TGF-β1 were significantly decreased (all P<0.05). Compared with the NC group, the expression of miR-223-3p and the mRNA and protein expression of Bax were significantly decreased in the miR-223-3p inhibitor group, while the mRNA and protein expression of ECT2, Bcl-2, VEGF and TGF-β1 were significantly increased (both P<0.05). Compared with the single processing group, the mRNA and protein expression of Bax in the miR-223-3p mimic+si-ECT2 group were significantly increased, while the mRNA and protein expression of ECT2, Bcl-2, VEGF, and TGF-β1 were significantly decreased (all P<0.05).

Conclusion

MiR-223-3p targets and inhibits the expression of ECT2, thus inhibiting the invasion and migration of BC cells, and promoting cell apoptosis. miR-223-3p plays a protective role in BC.

Remifentanil inhibits proliferation and promotes apoptosis of gastric cancer cells by regulating miR-519d-3p/STAT3 expression

BACKGROUND

Studies have shown that opioids can not only be used for tumor anesthesia and postoperative analgesia, but also have an inhibitory effect on the malignant biological behavior of tumor cells. As a highly efficient opioid receptor agonist, remifentanil has been reported to inhibit the proliferation and migration and induce apoptosis of tumor cells such as colon cancer, liver cancer, and lung adenocarcinoma cells. However, the effect of remifentanil on the proliferation and apoptosis of gastric cancer (GC) cells and the underlying mechanism are still unclear.

AIM

To study the effect of remifentanil on proliferation and apoptosis of GC cells and the potential mechanism involved.

METHODS

Human GC SGC7901 and BGC823 cells were cultured, and the effects of different concentrations of remifentanil on cell proliferation were detected by MTT assay. GC cells overexpressing miR-519d-3p, those with low expression of miR-519d-3p, and those overexpressing STAT3 were constructed and treated with remifentanil. Cell proliferation activity was measured by MTT assay at 24 h, 48 h, and 72 h after remifentanil treatment. Apoptosis was detected by flow cytometry at 48 h. qRT-PCR and Western blot were used to detect the expression levels of miR-519d-3p and STAT3 in cells, respectively. The dual luciferase reporter assay was used to test whether miR-519d-3p targets STAT3.

RESULTS

Remifentanil could effectively inhibit the proliferation of GC cells, induce their apoptosis, and promote the expression of miR-519d-3p. Overexpression of miR-519d-3p inhibited the proliferation of GC cells and induced their apoptosis, while inhibition of miR-519d-3p expression reversed the effect of remifentanil on the proliferation and apoptosis of GC cells. Dual luciferase reporter gene assay confirmed that miR-519d-3p negatively regulated STAT3 activity in GC cells. Overexpression of STAT3 reversed the effect of remifentanil on the proliferation and apoptosis of GC cells.

CONCLUSION

Remifentanil can inhibit the proliferation of GC cells and induce their apoptosis, which may be related to the regulation of mir-519d-3p/STAT3 expression.

MicroRNA-519d-3p inhibits cell proliferation and migration by targeting TROAP in colorectal cancer

Increasing evidence suggests that miR-519d-3p functions as tumor suppressor in several tumors, including breast cancer. However, its biological role in the development of colorectal cancer (CRC) still remains unclear. In this study, we found that miR-519d-3p expression level was remarkably down-regulated in CRC tissues samples and cell lines when compared to adjacent normal tissues and cell line by using qRT-PCR detection. Lower miR-519d-3p expression was significantly correlated with TNM stage, tumor size and lymph node metastasis. CRC patients with high level of miR-519d-3p had higher five-year survival rate than those with low expression of miR-519d-3p (p = 0.01178) using Kaplan-Meier analysis. Moreover, multivariate analysis suggested that miR-519d-3p expression might be an independent prognostic indicator for the survival of CRC patients. The in vitro functional analysis, including MTT, flow cytometry and transwell assays indicated that miR-519d-3p overexpression significantly suppressed cell proliferation, migration and invasion, induced cell cycle G0/G1 phase arrest and cell apoptosis of CRC cells. Furthermore, bioinformatics and luciferase reporter assays verified that trophinin associated protein (TROAP) was a direct target of miR-519d-3p in CRC cells. Using Oncomine database analysis, TROAP was confirmed to be upregulated in human CRC tissues. In addition, we found knockdown of TROAP presented similar inhibitory effects of miR-519d-3p overexpression in CRC cell function. In conclusion, miR-519d-3p might be a promising therapeutic strategy against human CRC by directly targeting TROAP.

MicroRNA519d and microRNA4758 can identify gangliogliomas from dysembryoplastic neuroepithelial tumours and astrocytomas

Glioneuronal tumours, including gangliogliomas and dysembryoplastic neuroepithelial tumours, represent the most common low-grade epilepsy-associated brain tumours and are a well-recognized cause of intractable focal epilepsy in children and young adults. Classification is predominantly based on histological features, which is difficult due to the broad histological spectrum of these tumours. The aim of the present study was to find molecular markers that can be used to identify entities within the histopathology spectrum of glioneuronal tumours. The focus of this study was on microRNAs (miRNAs). miRNAs are important post-transcriptional regulators of gene expression and are involved in the pathogenesis of different neurological diseases and oncogenesis. Using a miRNA array, miR-519d and miR-4758 were found to be upregulated in gangliogliomas (n=26) compared to control cortex (n=17), peritumoural tissue (n=7), dysembryoplastic neuroepithelial tumours (n=9) and astrocytomas (grade I-IV; subependymal giant cell astrocytomas, n=10; pilocytic astrocytoma, n=15; diffuse astrocytoma grade II, n=10; grade III, n=14 and glioblastoma n=15). Furthermore, the PI3K/AKT3/P21 pathway, which is predicated to be targeted by miR-519d and miR-4758, was deregulated in gangliogliomas. Functionally, overexpression of miR-519d in an astrocytic cell line resulted in a downregulation of CDKN1A (P21) and an increase in cell proliferation, whereas co-transfection with miR-4758 counteracted this effect. These results suggest that miR-519d and miR-4758 might work in concert as regulators of the cell cycle in low grade gliomas. Furthermore, these miRNAs could be used to distinguish gangliogliomas from dysembryoplastic neuroepithelial tumours and other low and high grade gliomas and may lead to more targeted therapy.

The Multifaceted Role of STAT3 in Mammary Gland Involution and Breast Cancer

Since seminal descriptions of signal transducer and activator of transcription 3 (STAT3) as a signal transducer and transcriptional regulator, which is most usually activated by phosphorylation of a specific tyrosine residue, a staggering wealth of research has delineated the key role of this transcription factor as a mediator of mammary gland postlactational regression (involution), and paradoxically, a pro-survival factor in breast cancer and some breast cancer cell lines. STAT3 is a critical regulator of lysosomal-mediated programmed cell death (LM-PCD) during mammary gland involution, where uptake of milk fat globules, and consequent high levels of free fatty acids, cause permeabilisation of lysosomal vesicle membranes, in turn leading to cathepsin protease leakage and cell death. A recent proteomic screen of STAT3-induced changes in lysosomal membrane protein components has highlighted wide-ranging effects of STAT3, which may coordinate LM-PCD via the stimulation of endocytosis, intracellular trafficking, and lysosome biogenesis. In parallel, STAT3 regulates the acute phase response during the first phase of involution, and it contributes to shaping the pro-tumourigenic 'wound healing' signature of the gland during the second phase of this process. STAT3 activation during involution is important across species, although some differences exist in the progression of involution in dairy cows. In breast cancer, a number of upstream regulators can lead to STAT3 activation and the effects of phosphorylation of STAT3 are equally wide-ranging. Recent studies have implicated microRNAs in some regulatory pathways. In this review, we will examine the multifaceted role of STAT3 in mammary gland involution and tumourigenesis, incorporating a review of these fundamental processes in tandem with a discussion of recent developments in this field.

Evaluation of the circulating MicroRNA-495 and Stat3 as prognostic and predictive biomarkers for lower extremity deep venous thrombosis

This study aims to elucidate the prognostic and predictive biomarker of miR-495 and Stat3 in peripheral blood in relation to lower extremity deep venous thrombosis (DVT). Patients with lower limb fractures were assigned into case and control groups. Rats were allocated into blank (normal rats), sham (normal rats), DVT, miR-495 mimic, miR-495 inhibitor, over-Stat3, and si-Stat3 groups. ELISA was used to detect levels of prothrombin time (PT), endothelin-1 (ET-1), Human Fibrinogen (FIB), D-Dimer, blood coagulation factors V and VIII, tissue type plasminogen activator (t-PA), platelet activating factor (PAF), protein C and Stat3. qRT-PCR was employed for the evaluation of the expressions of miR-495 and Stat3, while receiver operating characteristic (ROC) curve was constructed to assess the predictive value of miR-495 and Stat3 as well as the treatment outcomes of patients with lower limb fractures. Logistic regression analyses were conducted in order to correlate indexes and lower extremity DVT. miR-495 overexpression, t-PA, PAF, and protein C were confirmed to be protective factors, while Stat3 overexpression, PT, ET-1, FIB, D-Dimer, blood coagulation factor V, and VIII were all ultimately considered to be risk factors of lower extremity DVT. Stat3 was confirmed to be the target gene of miR-495. Compared with the blank group, the length and weight of the thrombus as well as the ratio between length and weight, mRNA and protein expression of Stat3 were reduced in the miR-495 mimic and si-Stat3 groups. Our findings suggest that through the suppression of Stat3 expression, miR-495 prohibits lower extremity DVT in peripheral blood.

MicroRNA-519d inhibits proliferation and induces apoptosis of human hypertrophic scar fibroblasts through targeting Sirtuin 7

MicroRNAs (miRNAs) play critical roles in various pathological processes, including hypertrophic scar (HS) formation. However, the precise role of miRNAs in HS formation remains largely unknown. In this study, we aimed to investigate the role of miR-519d in HS formation. We found that miR-519d expression was significantly downregulated in HS tissues and fibroblasts. Overexpression of miR-519d inhibited the expression of type I collagen (Col I), type III collagen (Col III) and α-smooth muscle actin (α-SMA) in HS fibroblasts. Moreover, overexpression of miR-519d reduced the proliferation and induced the apoptosis of HS fibroblasts. In contrast, suppression of miR-519d showed the opposite effects. Interestingly, Sirtuin 7 (SIRT7) was identified as a target gene of miR-519d. The results showed that miR-519d directly targeted the 3'-untranslated region of SIRT7 and negatively regulated its expression. Furthermore, miR-519d regulated the expression of TGF-β type I receptor (TGFBRI) and the phosphorylation of Smad2. Knockdown of SIRT7 by siRNA inhibited the expression of Col I, Col III and α-SMA, and reduced the proliferation and induced the apoptosis of HS fibroblasts. Overexpression of SIRT7 abrogated the effects mediated by miR-519d overexpression in HS fibroblasts. Overall, these results suggest that miR-519d inhibits the expression of extracellular matrix-associated genes, reduces the proliferation and induces the apoptosis of HS fibroblasts by targeting SIRT7, implying a suppressive role of miR-519d in HS formation. This study suggests that miR-519d may serve as a promising therapeutic target for treatment of human HS.

MiR-519d-3p suppresses breast cancer cell growth and motility via targeting LIM domain kinase 1

Breast cancer is the most common female cancer in women, and its estrogen receptor (ER)-negative subtype (ENBC) and triple-negative subtype (TNBC) have unfavorable prognosis in comparison with ER-positive subtype. MiRNAs are small noncoding RNAs that bind to the 3'-UTR region of targeting mRNAs to regulate gene expression. Mir-519d-3p was found to be associated with breast cancer for its potential role in proliferation and metastasis. To explore its potential role and mechanism of miR-519d-3p in breast carcinogenesis, we determined whether miR-519d-3p regulates breast cancer cell proliferation and motility by performing wound-healing assays and migration-invasion assays. We found that miR-519d-3p significantly inhibits proliferation and motility of ENBC and TNBC cells. Overexpression of miR-519d-3p arrested breast cancer cells in the G0/G1 phase and reduced the expression of CDK4, 6/Cyclin D1, and CDK2/Cyclin E1. It was reported that miR-519d-3p or miR-519d-3p expression was associated with cancer metastasis and clinical staging. Since LIM domain kinase 1 (LIMK1) was highly expressed in breast cancer and a major regulator of breast cancer growth and metastasis, we further demonstrated that LIMK1 is a potential target of miR-519d-3p by dual-luciferase report assay. Mir-519d-3p decreases LIMK1 expression at mRNA and protein levels, and the protein level and phosphorylation of cofilin 1 (CFL1), one of the key downstream targets of LIMK1. Our findings suggest that miR-519d-3p regulates the LIMK1/CFL1 pathway in breast cancer and this new venue could be targeted for future breast cancer therapy.

Quantification of STAT3 and VEGF expression for molecular diagnosis of lymph node metastasis in breast cancer

BACKGROUND

Axillary lymph node metastasis is associated with increased risk of regional recurrence, distant metastasis, and poor survival in breast malignant neoplasm. Expression of signal transducer and activator of transcription 3 (STAT3) is significantly associated with tumor formation, migration, and invasion in various cancers. In addition, vascular endothelial growth factor (VEGF) expression could promote angiogenesis and increase the risk of tumorigenesis. To determine correlations among STAT3 expression, VEGF, and clinicopathological data on lymph node involvement in breast cancer patients after surgery.

METHODS

The mRNA expression levels of STAT3 and VEGFs were measured in 45 breast invasive ductal carcinoma tissues, 45 peritumoral tissues, and 45 adjacent nontumor tissues by real-time quantitative reverse transcription-polymerase chain reaction (RT-qPCR). Postoperative pathological examination revealed explicit axillary lymph node involvement in all patients.

RESULTS

Average mRNA levels of STAT3 and VEGFs were the highest in breast invasive ductal carcinoma tissues, followed by peritumoral tissues. High expression of STAT3 showed significant positive correlation with high axillary lymph node involvement and progesterone receptor (PR), VEGF-C, VEGF-D, and vascular endothelial growth factor receptor (VEGFR)-3 expression. The expression levels of STAT3, VEGF-C, and VEGFR-3 were significantly higher in the tumor tissues of patients with axillary lymph node metastasis than in those of patients without the metastasis. Expression levels of VEGF-C and VEGFR-3 were also significantly higher in peritumoral tissues of patients with axillary lymph node metastasis. Positive correlations were found between STAT3 and VEGF-C/-D mRNA levels.

CONCLUSION

These data suggest that STAT3/VEGF-C/VEGFR-3 signaling pathway plays an important role in carcinogenesis and lymph-angiogenesis. Our findings suggest that STAT3 may be a potential molecular biomarker for predicting the involvement of axillary lymph nodes in breast cancer, and therapies targeting STAT3 may be important for preventing breast cancer metastasis.

MiR-519d impedes cisplatin-resistance in breast cancer stem cells by down-regulating the expression of MCL-1

Cancer stem cells are considered as the cell population which is responsible for chemoresistance and treatment failure in breast cancer patients. Therefore, it is urgent to explore the mechanism by which cancer stem cells survive under the treatment of chemotherapeutic drugs such as cisplatin. In this paper, we demonstrated significant decrease of miR-519d in breast cancer stem cells by quantitative RT-PCR analysis. Furthermore, we found the enforced expression of miR-519d in T-47D-cancer stem cells significantly increased their sensitivity to cisplatin through the apoptosis pathway. In addition, the gene of MCL-1, which is a member of pro-apoptotic Bcl-2 family, was found to be the target of miR-519d in T-47D-cancer stem cells. Our date demonstrated that enforced miR-519d expression enhanced the cisplatin-induced apoptosis through the MCL-1 dependent mitochondria pathway in breast cancer stem cells. Taken together, the present study suggests that miR-519d reduces chemoresistance in breast cancer stem cells, and understanding of miR-519d may be helpful for increasing the efficacy of chemotherapy.

The relationship between microRNAs and the STAT3-related signaling pathway in cancer

MicroRNAs are non-coding RNAs that regulate gene expression by targeting messenger RNA molecules in 3' untranslated region. Mounting evidence indicates that microRNAs regulate several factors to influence various biological activities that are related to carcinogenesis, including signal transducer and activator of transcription 3, which is a transcription factor that also acts as an oncogene. MicroRNAs influence signal transducer and activator of transcription 3 either by directly targeting or via other pathway components upstream or downstream of signal transducer and activator of transcription 3 such as Janus kinases, members of the suppressor of cytokine signaling family, and other genes that regulate cell proliferation, apoptosis, migration, invasion, and epithelial-mesenchymal transition. However, signal transducer and activator of transcription 3 activation changes the pattern of expression of microRNAs and mediates tumorigenesis. Moreover, the relationship between signal transducer and activator of transcription 3 and microRNAs varies among different kinds of cancers. A specific microRNA may act as an oncogene or tumor suppressor in different cancers, and microRNAs also directly or indirectly regulate signal transducer and activator of transcription 3 via pathways in the same cancers. In this review, we focus on the reciprocal regulation and roles of microRNAs and signal transducer and activator of transcription 3 in cancer, as well as describe current research progress on this relationship. A better understanding of this relationship may facilitate in the identification of targets for clinical therapeutics.

E2F-1 targets miR-519d to regulate the expression of the ras homolog gene family member C

E2F1 (E2F transcription factor 1) can act as a tumor suppressor or oncogene. We report the molecular mechanism of E2F1 in ovarian carcinoma tumorigenesis and progression. E2F1 expression levels in ovarian carcinoma tissue were examined by immunohistochemistry. After E2F1 plasmid transfection and E2F1-microRNA-519d (miR-519d)/si-RhoC (Ras homolog gene family member C) co-transfection, ovarian cancer cell phenotypes and the related molecules were examined in vitro and in vivo. E2F1 was overexpressed in type I and type II ovarian carcinoma as compared to normal ovary tissues and normal fallopian tube tissues, respectively. E2F1 overexpression promoted cell proliferation, G1–S progression, survival, migration, and invasion in vitro; miR-519d or siRhoC co-transfection reversed E2F1 oncogenic effects. E2F1 overexpression promoted tumor growth in vivo; miR-519d overexpression inhibited it. E2F1 overexpression increased RhoC, Bcl-2, cyclin D1, survivin, MMP2 (matrix metalloproteinase 2), MMP9, STAT3 (signal transducer and activator of transcription 3), and HuR (ELAV-like RNA-binding protein 1) expression; miR-519d overexpression decreased their expression. E2F1 downregulated miR-519d directly and miR-519d downregulated RhoC directly. Conversely, miR-519d directly downregulated E2F1, There is a direct repressive regulatory loop between E2F1 and miR-519d. We provide evidence that E2F1/miR-519d/RhoC is a promising signaling pathway for diagnosing and treating ovarian carcinoma.

Overexpression of miR-519d in lung adenocarcinoma inhibits cell proliferation and invasion via the association of eIF4H

Lung cancer is one of the deadliest types of cancer worldwide due to its high mortality rate. Adenocarcinoma constitutes 20%-30% of all lung cancers. In recent years, studies on the mechanisms of lung tumorigenesis and development have in part focused on the microRNAs for their crucial role in the progress of different cancers. As for our study, we demonstrated that miR-519d was differently downregulated and eIF4H was significantly overexpressed in lung adenocarcinoma via the detection of quantitative real-time polymerase chain reaction compared with the adjacent normal tissues. Furthermore, Cell Counting Kit-8 assay, colony formation assay, xenograft tumor experiment, Ki67 immunohistochemistry assay and transwell assay were performed to explain that the upregulated miR-519d could inhibit the proliferation and invasion of A549 and H1299 cells. To further advance our understanding of the mechanisms of miR-519d, we performed the bioinformatics analysis and the luciferase report assay. The results from these procedures revealed eIF4H to be one of the targets of miR-519d. Downregulated eIF4H was analogous to the overexpressed miR-519d obtained from miR-519d agomir and si-eIF4H transfection. In summary, it can be concluded that miR-519d targets eIF4H in lung adenocarcinoma to inhibit cell proliferation and invasion. This mechanism may offer new insights into the tumorigenesis and development of lung adenocarcinoma.

The function of miR-519d in cell migration, invasion, and proliferation suggests a role in early placentation

The processes of proliferation, migration, and invasion of extravillous trophoblasts are critical for placental implantation and early development, and directly influence pregnancy outcome. Dysregulation of these processes has been associated with placental dysfunction, implicated in clinical conditions such as preeclampsia and placental accreta. Among diverse microRNA (miRNA) species that are expressed in placental trophoblasts, members of the chromosome 19 miRNA cluster (C19MC) stand out in their nearly exclusive expression in the placenta. Recent research on the function of C19MC miRNAs in normal cell physiology and during tumorigenesis identified one C19MC member, miR-519d, as a regulator of cell migration, invasion, and interaction with the extracellular matrix. In this review, we focus on the function of miR-519d in placental trophoblasts, where miR-519d regulates cell migration and invasion, and its aberrant expression is associated with preeclampsia. In cancer, the function of miR-519d as an oncomiR or a tumor-suppressor is dependent upon the tumor type. Further research on the biological function and regulation of miR-519d may illuminate previously unknown mechanisms that control cell migration and invasion.

Polymorphisms in TIM-3 and breast cancer susceptibility in Chinese women: A case-control study

Previous studies have found associations between polymorphisms in T cell immunoglobulin and mucin domain 3 (TIM-3) and increased risks of various cancers. However, the association between TIM-3 polymorphisms and breast cancer (BC) remains uncertain. In this study, a total of 560 BC patients and 583 age, sex, and ethnicity-matched healthy controls from Northwest China were included. The polymorphisms were genotyped using Sequenom MassARRAY. The expression level of TIM-3 protein was detected by immunohistochemistry. We observed rs10053538 had a significantly increased risk of BC, comparing with the wild-type genotype even after Bonferroni correction. In addition, the rs4704853 G>A variants were more frequent among BC patients than the controls (GA + AA vs. GG: OR = 1.32, 95% CI = 1.03-1.69, P = 0.026); However, the significance was lost after Bonferroni correction (P = 0.078). Furthermore, rs10053538 was associated with lymph node metastasis. Age stratification revealed that among patients aged <49 years, those with the rs4704853 GA/AA genotype had a higher risk of BC; But there was no difference when Bonferroni correction was conducted. Immunohistochemical analysis showed that the expression of TIM-3 protein in the breast cancer tissues was higher in patients carrying the rs10053538 GT+TT genotype than those with GG genotype (P = 0.012). However, we failed to find any difference between BC patients and controls in any rs1036199 genetic model. These findings suggested that rs10053538 in TIM-3 might increase susceptibility to BC and promote the progression of BC in Chinese women.

Multiple regulation pathways and pivotal biological functions of STAT3 in cancer

STAT3 is both a transcription activator and an oncogene that is tightly regulated under normal physiological conditions. However, abundant evidence indicates that STAT3 is persistently activated in several cancers, with a crucial position in tumor onset and progression. In addition to its traditional role in cancer cell proliferation, invasion, and migration, STAT3 also promotes cancer through altering gene expression via epigenetic modification, inducing epithelial–mesenchymal transition (EMT) phenotypes in cancer cells, regulating the tumor microenvironment, and promoting cancer stem cells (CSCs) self-renewal and differentiation. STAT3 is regulated not only by the canonical cytokines and growth factors, but also by the G-protein-coupled receptors, cadherin engagement, Toll-like receptors (TLRs), and microRNA (miRNA). Despite the presence of diverse regulators and pivotal biological functions in cancer, no effective therapeutic inventions are available for inhibiting STAT3 and acquiring potent antitumor effects in the clinic. An improved understanding of the complex roles of STAT3 in cancer is required to achieve optimal therapeutic effects.

The polymorphism in miR-25 attenuated the oncogenic function in gastric cancer

miR-25 was identified as an essential oncogene by promoting the growth and metastasis through TOB1 in gastric cancer (GC). The function of the single nucleotide polymorphism (SNP) located in the mature region of miR-25 (rs41274221) has not been investigated. In this study, we aimed to explore the involvement of rs41274221 in miR-25 in gastric cancer. We found that SNP rs41274221 in miR-25 was participated in the occurrence of GC by acting as a tumor protective factor associating with the tumor growth and metastasis. Besides, further investigation found that upregulation of miR-25 with AA genotype could attenuate the proliferation and invasion of tumor cells caused by wild-type miR-25. The dual-luciferase reporter assay also confirmed that miR-25 harbored the A allele which caused an incapacitation of binding at the TOB1. In conclusion, rs41274221 in miR-25 was a subgroup which may protect the patients from further growth and metastasis of gastric cancer and might serve as a novel biomarker for the disease.

Mmu-miR-351 attenuates the survival of cardiac arterial endothelial cells through targeting STAT3 in the atherosclerotic mice

The signal transducer and activator of transcription 3 (STAT3) signaling pathway was involved in regulation of endothelial cell survival/apoptosis and was regarded as a target for prevention of atherosclerosis or other cardiovascular diseases. Factors, regulating STAT3 expression and activity, have aroused a wide range of interest, such as miRNAs or transcription factors. The aim of this study is to explore the role of miR-351, a miRNA found not long before, in the regulation of STAT3 expression and endothelial cell survival in the model mice with atherosclerosis (AS). Expression of miR-351 in the serum and cardiac arterial endothelial cells of the WT mice and AS mice was detected. Real-time qPCR analysis showed that miR-351 was upregulated in the serum and endothelial cells of the AS mice, displaying an opposite expression pattern with STAT3. To explore the role and mechanism of miR-351 in the endothelial cell survival, the miR-351 mimic was transfected in to the endothelial cells. MTT and Trypan Blue assays showed miR-351 attenuated the survival of endothelial cells. Our results of the TargetScan output and the 3'UTR luciferase reporter assay indicated that STAT3 was target of miR-351. Additionally, miR-351 resisted the elevation of STAT3 protein level and promotion of endothelial cell survival caused by SD19. Finally, our in vitro angiogenesis assay revealed that miR-351 suppressed angiogenesis and resisted the promotion of angiogenesis caused by SD19. In conclusion, miR-351 was upregulated in the atherosclerotic mice. MiR-351 can attenuate the survival of endothelial cells and suppress angiogenesis through targeting STAT3 in vitro.