MicroRNAs and signaling networks involved in epithelial-mesenchymal transition

The Promising Therapeutic Approaches for Radiation-Induced Pulmonary Fibrosis: Targeting Radiation-Induced Mesenchymal Transition of Alveolar Type II Epithelial Cells

Radiation-induced pulmonary fibrosis (RIPF) is a common consequence of radiation for thoracic tumors, and is accompanied by gradual and irreversible organ failure. This severely reduces the survival rate of cancer patients, due to the serious side effects and lack of clinically effective drugs and methods. Radiation-induced pulmonary fibrosis is a dynamic process involving many complicated and varied mechanisms, of which alveolar type II epithelial (AT2) cells are one of the primary target cells, and the epithelial-mesenchymal transition (EMT) of AT2 cells is very relevant in the clinical search for effective targets. Therefore, this review summarizes several important signaling pathways that can induce EMT in AT2 cells, and searches for molecular targets with potential effects on RIPF among them, in order to provide effective therapeutic tools for the clinical prevention and treatment of RIPF.

Epithelial-to-Mesenchymal Transition in Metastasis: Focus on Laryngeal Carcinoma

In epithelial neoplasms, such as laryngeal carcinoma, the survival indexes deteriorate abruptly when the tumor becomes metastatic. A molecular phenomenon that normally appears during embryogenesis, epithelial-to-mesenchymal transition (EMT), is reactivated at the initial stage of metastasis when tumor cells invade the adjacent stroma. The hallmarks of this phenomenon are the abolishment of the epithelial and acquisition of mesenchymal traits by tumor cells which enhance their migratory capacity. EMT signaling is mediated by complex molecular pathways that regulate the expression of crucial molecules contributing to the tumor’s metastatic potential. Effectors of EMT include loss of adhesion, cytoskeleton remodeling, evasion of apoptosis and immune surveillance, upregulation of metalloproteinases, neovascularization, acquisition of stem-cell properties, and the activation of tumor stroma. However, the current approach to EMT involves a holistic model that incorporates the acquisition of potentials beyond mesenchymal transition. As EMT is inevitably associated with a reverse mesenchymal-to-epithelial transition (MET), a model of partial EMT is currently accepted, signifying the cell plasticity associated with invasion and metastasis. In this review, we identify the cumulative evidence which suggests that various aspects of EMT theory apply to laryngeal carcinoma, a tumor of significant morbidity and mortality, introducing novel molecular targets with prognostic and therapeutic potential.

MiR-135a-5p suppresses trophoblast proliferative, migratory, invasive, and angiogenic activity in the context of unexplained spontaneous abortion

BACKGROUND

Spontaneous abortions (SA) is amongst the most common complications associated with pregnancy in humans, and the underlying causes cannot be identified in roughly half of SA cases. We found miR-135a-5p to be significantly upregulated in SA-associated villus tissues, yet the function it plays in this context has yet to be clarified. This study explored the function of miR-135a-5p and its potential as a biomarker for unexplained SA.

METHOD

RT-qPCR was employed for appraising miR-135a-5p expression within villus tissues with its clinical diagnostic values being assessed using ROC curves. The effects of miR-135a-5p in HTR-8/SVneo cells were analyzed via wound healing, Transwell, flow cytometry, EdU, CCK-8, and tube formation assays. Moreover, protein expression was examined via Western blotting, and interactions between miR-135a-5p and PTPN1 were explored through RIP-PCR, bioinformatics analyses and luciferase reporter assays.

RESULTS

Relative to normal pregnancy (NP), villus tissue samples from pregnancies that ended in unexplained sporadic miscarriage (USM) or unexplained recurrent SA (URSA) exhibited miR-135a-5p upregulation. When this miRNA was overexpressed in HTR-8/SVneo cells, their migration, proliferation, and cell cycle progression were suppressed, as were their tube forming and invasive activities. miR-135a-5p over-expression also downregulated the protein level of cyclins, PTPN1, MMP2 and MMP9. In RIP-PCR assays, the Ago2 protein exhibited significant miR-135a-5p and PTPN1 mRNA enrichment, and dual-luciferase reporter assays indicated PTPN1 to be a bona fide miR-135a-5p target gene within HTR-8/SVneo cells.

CONCLUSION

miR-135a-5p may suppress trophoblast migratory, invasive, proliferative, and angiogenic activity via targeting PTPN1, and it may thus offer value as a biomarker for unexplained SA.

Non-Coding RNA in Penile Cancer

Penile cancer (PC) still presents a health threat for developing countries, in particular Brazil. Despite this, little progress has been made on the study of markers, including molecular ones, that can aid in the correct management of the patient, especially concerning lymphadenectomy. As in other neoplasms, non-coding RNAs (ncRNAs) have been investigated for penile cancer, with emphasis on microRNAs, piRNAs (PIWI-interacting small RNAs), and long non-coding RNAs (LncRNAs). In this context, this review aims to assemble the available knowledge on non-coding RNA linked in PC, contributing to our understanding of the penile carcinogenesis process and addressing their clinical relevance. ncRNAs are part of the novel generation of biomarkers, with high potential for diagnosis and prognosis, orientating the type of treatment. Furthermore, its versatility regarding the use of paraffin samples makes it possible to carry out retrospective studies.

Evaluation on epithelial-mesenchymal state and microRNAs focusing on isolated alveolar epithelial cells from bleomycin injured rat lung

Several studies using bleomycin (BLM)-induced lung injury rat model revealed that epithelial-mesenchymal transition (EMT) contributes to pulmonary fibrosis. Conversely, microRNAs (miRNAs) are considered as useful markers of various diseases. In the present study, we aimed to characterize the EMT state through focusing on alveolar epithelial cells and identify the miRNAs that can be used as markers to predict pulmonary fibrosis using a BLM-induced lung injury rat model. Intratracheal administration of BLM increased hydroxyproline, a component of collagen, in lung tissues at day 14, but not at day 7. However, BLM induced EMT at day 7, which was accompanied with increased mRNA expression of α-smooth muscle actin, a representative EMT marker, in alveolar epithelium, thereby suggesting that EMT occurs prior to pulmonary fibrosis in alveolar epithelial cells. Using this rat model, the expression levels of several EMT-associated miRNAs were examined, and miR-222 was found to be upregulated in alveolar epithelial cells as well as bronchoalveolar lavage fluid from day 3. Our findings indicate that EMT in alveolar epithelial cells may occur before pulmonary fibrosis, and miR-222 may be used as a potential marker for early prediction of pulmonary fibrosis.

EMT Participates in the Regulation of Exosomes Secretion and Function in Esophageal Cancer Cells

Epithelial-mesenchymal transition (EMT) is a key step in tumor invasion and distant metastasis. Abundant evidence has documented that exosomes can mediate EMT of tumor cells and endow them with the ability of invasion and migration. However, there are few studies focusing on whether EMT can reverse the secretion of exosomes. In this study, 2 esophageal cancer cells (FLO-1 and SK-GT-4) were selected to compare the migration ability and EMT activation, and to further analyze the secretion ability of exosomes of the 2 cell lines. According to the results, inhibited activation of EMT in FLO-1 cells with relatively high migration ability could effectively reduce the secretion of exosomes. Besides, in SK-GT-4 cells, EMT activation induced by TGF-β could promote the secretion of exosomes. FLO-1 cell derived exosomes exhibited a paracrine effect of promoting the migration of SK-GT-4 cells, and the use of EMT inhibitors could weaken this ability. Furthermore, inhibition of EMT could change the relative content of some miRNAs in exosomes, with a particularly significant downregulation in the expression of miR-196-5p, miR-21-5p and miR-194-5p. Significantly, artificial transfection of the 3 miRNAs into exosomes by electroporation resulted in the recovery of migration-promoting effect of exosomes. Subsequent experiments further revealed that the effect of EMT on these miRNAs could be explained by the intracellular transcription level or the specific sorting mechanism of exosomes. To sum up, our study undoubtedly reveals that EMT has a regulatory effect on exosomes in the quantity and contents in esophageal cancer cells. Significantly, findings in our study provide experimental evidence for the interaction of EMT with the secretion and sorting pathway of exosomes, and also give a new direction for the further study of tumor metastasis.

miR-200c-3p Regulates Epitelial-to-Mesenchymal Transition in Epicardial Mesothelial Cells by Targeting Epicardial Follistatin-Related Protein 1

Recent findings suggest that epithelial to mesenchymal transition (EMT), a key step during heart development, is involved in cardiac tissue repair following myocardial infarction (MI). MicroRNAs (miRNAs) act as key regulators in EMT processes; however, the mechanisms by which miRNAs target epicardial EMT remain largely unknown. Here, by using an in vitro model of epicardial EMT, we investigated the role of miRNAs as regulators of this process and their potential targets. EMT was induced in murine epicardial-mesothelial cells (EMCs) through TGF β1 treatment for 48, 72, and 96 h as indicated by the expression of EMT-related genes by qRT-PCR, WB, and immunofluorescence. Further, enhanced expression of stemness genes was also detected. Among several EMT-related miRNAs, miR-200c-3p expression resulted as the most strongly suppressed. Interestingly, we also found a significant upregulation of Follistatin-related protein 1 (FSTL1), a miR-200c predicted target already identified as a potent cardiogenic factor produced by epicardial cells that promotes regeneration following MI. Dual-luciferase reporter assay demonstrated that miR-200c-3p directly targeted the 3'-untranslated region of FSTL1 in EMCs. Consistently, WB analysis showed that knockdown of miR-200c-3p significantly increased FSTL1 expression, whereas overexpression of miR-200c-3p counteracted TGF β1-mediated FSTL1 upregulation. Importantly, FSTL1 silencing maintained epithelial features in EMCs, despite EMT induction by TGF β1, and attenuated EMT-associated traits, including migration and stemness. In conclusion, epicardial FSTL1, an important cardiogenic factor in its secreted form, induces EMT, stemness, and migration of EMCs in a miR-200c-3p dependent pathway.

ARHGEF10L Promotes Cervical Tumorigenesis via RhoA-Mediated Signaling

Background

Rho guanine nucleotide exchange factor 10-like protein (ARHGEF10L) is a member of the guanine nucleotide exchange factor family, which regulates Rho GTPase activities, thus contributing to tumorigenesis. Our previous study demonstrated a strong association between the ARHGEF10L gene and the risk of cervical carcinoma. This study investigated the pathogenic role and mechanism of ARHGEF10L in cervical tumors.

Methods

The HeLa cell line, which was derived from cervical carcinoma, was transfected with ARHGEF10L-overexpressing plasmids or anti-ARHGEF10L siRNA. Cell counting kit-8 assays, wound-healing assays, and cell apoptosis assays were performed to investigate the effects of ARHGEF10L on cell activities. A Rho pull-down assay and RNA-sequencing analysis were performed to investigate the pathogenic pathway of ARHGEF10L involvement in cervical tumors.

Results

ARHGEF10L overexpression promoted cell proliferation and migration, reduced cell apoptosis, and induced epithelial-to-mesenchymal transition (EMT) via downregulation of E-cadherin and upregulation of N-cadherin and Slug in transfected HeLa cells. The overexpression of ARHGEF10L also upregulated GTP-RhoA, ROCK1, and phospho-ezrin/radixin/moesin (ERM) expression in HeLa cells. RNA-sequencing analysis detected altered transcription of 31 genes in HeLa cells with ARHGEF10L overexpression. Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) pathway analyses identified significant differences in cyclin-dependent protein serine/threonine kinase activity, cell responses to vitamin A, and Toll-like receptor signaling pathways. Both real-time PCR and Western blotting verified the increased expression of heat shock 70 kDa protein 6 (HSPA6) in ARHGEF10L-overexpressing HeLa cells. Since we reported that ARHGEF10L played a role through RhoA-ROCK1-ERM signaling, an important pathway in tumorigenesis, and stimulated EMT and HSPA6 expression in liver tumors and gastric tumor cells, we suggest that ARHGEF10L is a novel oncogene in many tumors.

HOXD13 suppresses prostate cancer metastasis and BMP4-induced epithelial-mesenchymal transition by inhibiting SMAD1

The HOX genes are a group of highly conserved Homeobox-containing genes that control the body plan organization during development. However, their contributions to tumorigenesis and tumor progression remain uncertain and controversial. Here we provided evidence of tumor-suppressive activity of HOXD13 in prostate cancer. HOXD13 depletion contributes to more aggressiveness of prostate cancer cells in vitro and in vivo. These effects were corroborated in a metastatic mice model, where we observed more bone metastatic lesions formed by prostate cancer cells with HOXD13 ablation. Mechanistically, HOXD13 prevents BMP4-induced epithelial-mesenchymal transition (EMT) by inhibiting mothers against decapentaplegic homolog 1 (SMAD1) transcription. Both bioinformation and our tissue microarray cohort data show that HOXD13 expression inversely correlated in advanced prostate cancer patient specimens. Our findings establish HOXD13 as a negative regulator of prostate cancer progression and metastasis by preventing BMP4/SMAD1 signaling, and potentially suggest new strategies for targeting metastatic prostate cancer.

Feasibility of Bone Marrow Mesenchymal Stem Cell-Mediated Synthetic Radiosensitive Promoter-Combined Sodium Iodide Symporter for Radiogenetic Ovarian Cancer Therapy

Ovarian cancer is the most lethal gynecological cancer, most patients relapse within 12-24 months, and eventually die, especially platinum-resistant patients. Gene therapy has been one of the most potential methods for tumor treatment. Bone marrow mesenchymal stem cells (BMSCs) have been used for systemic delivery of therapeutic genes to solid tumors. Sodium iodide symporter (NIS) is an intrinsic membrane glycoprotein and can concentrate ¹³¹I, which is important for radionuclide therapy and nuclear medicine imaging in recent years. However, the rapid iodine efflux has become a bottleneck for NIS-mediated radionuclide gene therapy. Our previous studies found that the early growth response-1 (Egr1) promoter containing CC(A/T)6GG (CArG) elements had an ¹³¹I radiation-positive feedback effect on the NIS gene. Other research showed the synthesized Egr1 promoter containing four CArG elements, E4, was nearly three times as sensitive as the Egr1 promoter. In our study, BMSC-E4-NIS was engineered to express NIS under the control of E4 promoter using lentivirial vectors. After BMSC-E4-NIS implantation, no tumors were seen in BALB/c nude mice and BMSC-E4-NIS did not promote the growth of SKOV3 tumor. BMSCs migrated toward ovarian cancer samples in chemotaxis assays and to ovarian tumors in mice. Using micro-single-photon emission computed tomography/computed tomography (SPECT/CT) imaging, we found that E4 promoter produced a notable increase in ¹²⁵I uptake after ¹³¹I irradiation, the radionuclide uptake is almost three and six times more than Egr1 and cytomegalovirus (CMV) promoters. These studies confirmed the feasibility of using BMSCs as carriers for lentivirus-mediated E4-NIS gene therapy for ovarian cancer. Further research on BMSC-E4-NIS gene therapy for ovarian cancer in vivo will also be carried on, and if successful, this might provide a new adjuvant therapeutical option for platinum-resistant ovarian cancer patients and provide a new method for dynamic evaluation of curative effect.

MicroRNA and ER stress in cancer

The development of biological technologies in genomics, proteomics, and bioinformatics has led to the identification and characterization of the complete set of coding genes and their roles in various cellular pathways in cancer. Nevertheless, the cellular pathways have not been fully figured out like a jigsaw puzzle with missing pieces. The discovery of noncoding RNAs including microRNAs (miRNAs) has provided the missing pieces of the cellular pathways. Likewise, miRNAs have settled many questions of inexplicable patches in the endoplasmic reticulum (ER) stress pathways. The ER stress-caused pathways typified by the unfolded protein response (UPR) are pivotal processes for cellular homeostasis and survival, rectifying uncontrolled proteostasis and determining the cell fate. Although various factors and pathways have been studied and characterized, the understanding of the ER stress requires more wedges to fill the cracks of knowledge about the ER stress pathways. Moreover, the roles of the ER stress and UPR are still controversial in cancer despite their strong potential to promote cancer. The noncoding RNAs, in particular, miRNAs aid in a better understanding of the ER stress and its role in cancer. In this review, miRNAs that are the more-investigated subtype of noncoding RNAs are focused on the interpretation of the ER stress in cancer, following the introduction of miRNA and ER stress.

Extracellular MicroRNAs as Intercellular Mediators and Noninvasive Biomarkers of Cancer

Simple Summary

There are an extensive number of publications regarding the role of endogenous miRNAs as regulators of gene expression in cancer. However, extracellular miRNAs have emerged as a novel mechanism of cell-to-cell communication in normal conditions and disease and have drawn a large amount of interest as regulators of gene expression and as potential non-invasive biomarkers in cancer. Despite this high interest and the abundance of research on the biology and role of extracellular miRNAs in cancer, they are not yet completely understood. The aim of this review is to highlight the relevant biological characteristics of extracellular miRNAs that enable them to function as intercellular mediators of gene expression regulation and provide the recently published evidence of the specific role of extracellular miRNAs in tumor development and progression.

Abstract

MicroRNAs (miRNAs) are released by different types of cells through highly regulated mechanisms under normal and pathological conditions. These extracellular miRNAs can be delivered into recipient cells for functional purposes, acting as cell-to-cell signaling mediators. It has been discovered that cancer cells release miRNAs into their surroundings, targeting normal cells or other cancer cells, presumably to promote tumor development and progression. These extracellular miRNAs are associated with oncogenic mechanisms and, because they can be quantified in blood and other bodily fluids, may be suitable noninvasive biomarkers for cancer detection. This review summarizes recent evidence of the role of extracellular miRNAs as intercellular mediators, with an emphasis on their role in the mechanisms of tumor development and progression and their potential value as biomarkers in solid tumors. It also highlights the biological characteristics of extracellular miRNAs that enable them to function as regulators of gene expression, such as biogenesis, gene silencing mechanisms, subcellular compartmentalization, and the functions and mechanisms of release.

Competing Endogenous RNA Networks in the Epithelial to Mesenchymal Transition in Diffuse-Type of Gastric Cancer

Simple Summary

The diffuse-type of gastric cancer is associated with epithelial to mesenchymal transition. Loss of E-cadherin expression is the hallmark of this process and is largely due to the upregulation of the transcription factors ZEB1/2, Snail, Slug, and Twist1/2. However, miRNA and lncRNAs can also participate through these transcription factors which directly target E-cadherin. The competing endogenous RNA (ceRNA) network hypothesis state that lncRNA can sponge the miRNA pool that targets these transcripts. Based on the lack of said networks in the epithelial to mesenchymal transition, we performed a prediction analysis that resulted in novel ceRNA networks which will expand our knowledge of the molecular basis of the diffuse-type of gastric cancer.

Abstract

The diffuse-type of gastric cancer (DGC), molecularly associated with epithelial to mesenchymal transition (EMT), is increasing in incidence. Loss of E-cadherin expression is the hallmark of the EMT process and is largely due to the upregulation of the EMT-inducing transcription factors ZEB1/2, Snail, Slug, and Twist1/2. However, ncRNA, such as miRNA and lncRNAs, can also participate in the EMT process through the direct targeting of E-cadherin and other EMT-inducing transcription factors. Additionally, lncRNA can sponge the miRNA pool that targets these transcripts through competing endogenous RNA (ceRNA) networks. In this review, we focus on the role of ncRNA in the direct deregulation of E-cadherin, as well as EMT-inducing transcription factors. Based on the relevance of the ceRNA network hypothesis, and the lack of said networks in EMT, we performed a prediction analysis for all miRNAs and lncRNAs that target E-cadherin, as well as EMT-inducing transcription factors. This analysis resulted in novel predicted ceRNA networks for E-cadherin and EMT-inducing transcription factors (EMT-TFs), as well as the expansion of the molecular basis of the DGC.

Effects of miR-135a-5p and miR-141 on proliferation, invasion and apoptosis of colorectal cancer SW620 cells

Effects of miR-135a-5p and miR-141 on the biological function of colorectal cancer SW620 cells were investigated. Fifty-four specimens of cancer tissues and 54 specimens of corresponding adjacent tissues in colon cancer patients who were treated in The Central Hospital of Wuhan from March 2014 to March 2015 were collected. RT-PCR was used to detect the expression levels of miR-135a-5p and miR-141 in cancer tissues and adjacent tissues. The miR-135a-5p inhibitor and miR-141 mimic carriers were established. The cell proliferation was detected by CCK8, the invasion ability of cells in vitro was evaluated by Transwell chamber, and cell apoptosis of each group was detected by flow cytometry. The results of RT-qPCR showed that expression levels of miR-135a-5p in colorectal cancer tissues were significantly higher than those in adjacent tissues, the expression levels of miR-141 in colorectal cancer tissues were significantly lower than those in adjacent tissues, and the difference was statistically significant (P<0.001). The cell survival rates of the miR-135a-5p inhibitor group and the miR-141 mimic group were significantly lower than those of the NC group and the blank group 48 and 72 h after transfection (P<0.001). The number of invasive cells in the miR-135a-5p inhibitor group and the miR-141 mimic group was significantly lower than that in the blank group and the NC group (P<0.001). Apoptosis rate was significantly higher than that of the NC group and the blank group (P<0.001). In conclusion, low expression levels of miR-135a-5p and miR-141 in colorectal adenomas suggested that miR-135a-5p and miR-141 could act as tumor suppressors in the development of colorectal adenomas; miR-135a-5p and miR-141 inhibited the proliferation and invasion of colon cancer SW620 cells and promoted apoptosis of colon cancer cells.

Role of plasminogen activator inhibitor-1 in methotrexate-induced epithelial-mesenchymal transition in alveolar epithelial A549 cells

There is increasing evidence that epithelial-mesenchymal transition (EMT) contributes to the development of organ fibrosis. We demonstrated that methotrexate (MTX) clearly induced EMT through the transforming growth factor (TGF)-β-related signaling pathway in human alveolar epithelial cell line, A549. However, critical factors associated with MTX-induced EMT have not yet been identified. In our study, we attempted to identify factors playing a crucial role in MTX-induced EMT in A549 cells. We focused on plasminogen activator inhibitor-1 (PAI-1) as the possible target for the prevention of MTX-induced EMT-related lung injury. Comprehensive gene expression analysis by microarray revealed that mRNA expression level of PAI-1 was clearly increased by MTX treatment. In addition, using several cloned A549 cells, we found a good correlation between MTX-induced increase in mRNA expression levels of α-smooth muscle actin (SMA), a representative EMT marker, and PAI-1. Furthermore, MTX upregulated mRNA and protein expression levels of PAI-1 in A549 cells; this upregulation was canceled by co-treatment with SB431542, a TGF-β-related signaling pathway inhibitor. Notably, tiplaxtinin, a PAI-1 inhibitor, and knockdown of urokinase-type plasminogen activator receptor (uPAR) prevented MTX-induced EMT in A549 cells. These findings indicate that MTX may induce EMT via upregulation of PAI-1 expression and interaction of PAI-1 with uPAR in A549 cells.

miR-93-5p enhances migration and invasion by targeting RGMB in squamous cell carcinoma of the head and neck

Invasion and metastasis represent the primary causes of therapeutic failure in patients diagnosed with squamous cell carcinoma of the head and neck (SCCHN). Therefore, disease prediction and inhibition of invasion and metastasis are critical for enhancing the survival of patients with SCCHN. Our previous study revealed that increased expression of miR-93-5p is associated with poor prognosis in SCCHN; however, the mechanism underlying the oncogenic functions of miR-93-5p in SCCHN migration and invasion remains unclear. Using qPCR analyses, transwell assays, and scratch tests, we demonstrated that expression of ectopic miR-93-5p induced the migration and invasion of SCCHN, and this was accompanied by corresponding alterations in biomarkers and transcription factors specific for epithelial-mesenchymal transition (EMT). Luciferase reporter assays were used to demonstrate that miR-93-5p directly targeted the 3' UTR of RGMB, and we further found that the tumor-promoting functions of miR-93-5p were partly mediated by targeting RGMB, whose downregulation also promoted the migration and invasion of SCCHN. Overall, our results indicate that miR-93-5p acts as an oncogene in the regulation of migration and invasion by suppressing RGMB in SCCHN. These findings provide novel evidence that miR-93-5p may serve as a valuable predictive biomarker and potential intervention target in patients with SCCHN.

MiR-195-5p Inhibits Malignant Progression of Cervical Cancer by Targeting YAP1

Purpose

Our previous studies have shown that miR-195 is reduced in cervical cancer tissues, and that upregulation of miR-195 suppressed cervical cancer cell growth and induced a cell cycle block. In this study, we aimed to further elucidate the mechanism of action between miR-195-5p and Yes-associated protein 1 (YAP1) in the malignant progression of cervical cancer.

Methods

MiR-195-5p and YAP1 were detected using qRT-PCR in cervical cancer cells transfected with miR-195-5p mimics or inhibitor. Cell proliferation, migration, and invasion ability were detected using MTT, wound healing, and transwell invasion assays. Dual luciferase reporter assay, qRT-PCR, and Western blot analysis were used to demonstrate that YAP1 was a target of miR-195-5p.

Results

Our results showed that miR-195-5p is negatively correlated with YAP1 protein levels but not with mRNA expression. Moreover, upregulation of miR-195-5p by transient transfection with miR-195-5p mimics in HeLa and SiHa cells inhibited cell proliferation, migration ability, invasiveness, and the EMT. Conversely, miR-195-5p downregulation produced opposite results. In addition, multiple miRNA target prediction sites showed that YAP1 was a potential target gene; this was confirmed by dual luciferase assay. Rescue experiments further confirmed that YAP1 is involved in miR-195-5p-mediated inhibition of proliferation, migration ability, invasiveness, and the EMT of cervical cancer cells.

Conclusion

Taken together, our data suggest that miR-195-5p may act as a tumor suppressor which could provide a theoretical basis for cervical cancer patient targeted therapy.

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

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

MicroRNA-1275 induces radiosensitization in oesophageal cancer by regulating epithelial-to-mesenchymal transition via Wnt/β-catenin pathway

Acquired radioresistance is one of the main obstacles for the anti-tumour efficacy of radiotherapy in oesophageal cancer (EC). Recent studies have proposed microRNAs (miRNAs) as important participators in the development of radioresistance in various cancers. Here, we investigated the role of miR-1275 in acquired radioresistance and epithelial-mesenchymal transition (EMT) in EC. Firstly, a radioresistant cell line KYSE-150R was established, with an interesting discovery was observed that miR-1275 was down-regulated in KYSE-150R cells compared to the parental cells. Functionally, miR-1275 inhibition elevated radioresistance in KYSE-150 cells via promoting EMT, whereas enforced expression of miR-1275 increased radiosensitivity in KYSE-150R cells by inhibiting EMT. Mechanically, we demonstrated that miR-1275 directly targeted WNT1 and therefore inactivated Wnt/β-catenin signalling pathway in EC cells. Furthermore, WNT1 depletion countervailed the promoting effect of miR-1275 suppression on KYSE-150 cell radioresistance through hampering EMT, whereas WNT1 overexpression rescued miR-1275 up-regulation-impaired EMT to reduce the sensitivity of KYSE-150R cells to radiation. Collectively, our findings suggested that miR-1275 suppressed EMT to encourage radiosensitivity in EC cells via targeting WNT1-activated Wnt/β-catenin signalling, providing a new therapeutic outlet for overcoming radioresistance of patients with EC.

Mesenchymal stem cells as carrier of the therapeutic agent in the gene therapy of blood disorders

Nonhematopoietic stem cells as a delivery platform of therapeutic useful genes have attracted widespread attention in recent years, owing to gained a long lifespan, easy separation, high proliferation, and high transfection capacity. Mesenchymal stem/stromal cells (MSCs) are the choice of the cells for gene and cell therapy due to high self-renewal capacity, high migration rate to the site of the tumor, and with immune suppressive and anti-inflammatory properties. Hence, it has a high potential of safety genetic modification of MSCs for antitumor gene expression and has paved the way for the clinical application of these cells to target the therapy of cancers and other diseases. The aim of gene therapy is targeted treatment of cancers and diseases through recovery, change, or enhancement cell performance to the sustained secretion of useful therapeutic proteins and induction expression of the functional gene in intended tissue. Recent developments in the vectors designing leading to the increase and durability of expression and improvement of the safety of the vectors that overcome a lot of problems, such as durability of expression and the host immune response. Nowadays, gene therapy approach is used by MSCs as a delivery vehicle in the preclinical and the clinical trials for the secretion of erythropoietin, recombinant antibodies, coagulation factors, cytokines, as well as angiogenic inhibitors in many blood disorders like anemia, hemophilia, and malignancies. In this study, we critically discuss the status of gene therapy by MSCs as a delivery vehicle for the treatment of blood disorders. Finally, the results of clinical trial studies are assessed, highlighting promising advantages of this emerging technology in the clinical setting.

TGFβ1- miR-140-5p axis mediated up-regulation of Flap Endonuclease 1 promotes epithelial-mesenchymal transition in hepatocellular carcinoma

Flap Endonuclease 1 (FEN1) is a known oncogene in an array of cancers, but its role in hepatocellular carcinoma (HCC) remains obscure. In this study, we report that FEN1 expression was elevated in the Cancer Genome Atlas (TCGA) database which was verified in HCC tissue and hepatoma cell lines. Pearson correlation analysis indicated that FEN1 was involved in HCC metastasis. We demonstrated that FEN1 silencing inhibits HCC cell epithelial-mesenchymal transition (EMT), invasion and migration in vitro and significantly suppressed tumor growth and metastasis in vivo. Conversely, FEN1 overexpression in HCC cells enhanced these metastatic processes. We further confirmed that FEN1 was a direct target of miR-140-5p, which was down-regulated in HCC tissues, and negatively correlated with FEN1 expression. Moreover, low miR-140-5p levels and high FEN1 expression predicted a poor clinical outcome. The effects of FEN1 overexpression could be partially abolished by miR-140-5p. miR-140-5p down-regulation and FEN1 overexpression were observed in a TGFβ1 induced EMT model. TGFβ1 mediated EMT could be blocked by miR-140-5p overexpression or FEN1 silencing. Taken together, our findings suggest that FEN1 is regulated by the TGFβ1- miR-140-5p axis and promotes EMT in HCC.

TGF-β-Mediated Epithelial-Mesenchymal Transition and Cancer Metastasis

Transforming growth factor β (TGF-β) is a secreted cytokine that regulates cell proliferation, migration, and the differentiation of a plethora of different cell types. Consistent with these findings, TGF-β plays a key role in controlling embryogenic development, inflammation, and tissue repair, as well as in maintaining adult tissue homeostasis. TGF-β elicits a broad range of context-dependent cellular responses, and consequently, alterations in TGF-β signaling have been implicated in many diseases, including cancer. During the early stages of tumorigenesis, TGF-β acts as a tumor suppressor by inducing cytostasis and the apoptosis of normal and premalignant cells. However, at later stages, when cancer cells have acquired oncogenic mutations and/or have lost tumor suppressor gene function, cells are resistant to TGF-β-induced growth arrest, and TGF-β functions as a tumor promotor by stimulating tumor cells to undergo the so-called epithelial-mesenchymal transition (EMT). The latter leads to metastasis and chemotherapy resistance. TGF-β further supports cancer growth and progression by activating tumor angiogenesis and cancer-associated fibroblasts and enabling the tumor to evade inhibitory immune responses. In this review, we will consider the role of TGF-β signaling in cell cycle arrest, apoptosis, EMT and cancer cell metastasis. In particular, we will highlight recent insights into the multistep and dynamically controlled process of TGF-β-induced EMT and the functions of miRNAs and long noncoding RNAs in this process. Finally, we will discuss how these new mechanistic insights might be exploited to develop novel therapeutic interventions.