Prognostic Implications of miR-302a/b/c/d in Human Gastric Cancer

Dexmedetomidine promotes ferroptotic cell death in gastric cancer via hsa_circ_0008035/miR-302a/E2F7 axis

Dexmedetomidine (DEX), a common anesthetic, has significant effects on the biological features of cancer cells. Although numerous studies have been published on the impact of DEX on the biological characteristics of GC cells, the mechanism remains unknown. This study aimed to explore the effect of DEX on the biological properties of GC cells. DEX suppressed the viability and increased the apoptosis of GC cells in vitro and inhibited tumor growth in vivo. Besides, DEX raised the levels of reactive oxygen species (ROS) and iron, but decreased the levels of glutathione (GSH), glutathione peroxidase 4 (GPX4), and solute carrier family 7 member 11 (SLC7A11) in GC cells, which were abolished by Ferrostatin-1 (the inhibitor of ferroptosis) treatment. In addition, the level of circ0008035 and E2F7 were downregulated, but miR-302a level was upregulated in DEX-treated GC cells. Circ0008035 increased the expression of E2F2 by acting as a sponge for miR-302a. Circ0008035 inhibited DEX-induced ferroptotic cell death in GC cells, which was reversed by miR-302a overexpression or E2F7 reduction. Taken together, DEX mediated ferroptotic cell death in GC through regulating the circ0008035/miR-302a/E2F7 axis, suggesting a feasible therapy option for GC.

Novel Risk Associations between microRNA Polymorphisms and Gastric Cancer in a Chilean Population

Gastric cancer (GC) is the fifth leading cause of cancer deaths in the world, with variations across geographical regions and ethnicities. Emerging evidence indicates that miRNA expression is dysregulated in GC and its polymorphisms may contribute to these variations, which has yet to be explored in Latin American populations. In a case-control study of 310 GC patients and 311 healthy donors from Chile, we assessed the association of 279 polymorphisms in 242 miRNA genes. Two novel polymorphisms were found to be associated with GC: rs4822739:C>G (miR-548j) and rs701213:T>C (miR-4427). Additionally, rs1553867776:T>TCCCCA (miR-4274) and rs12416605:C>T (miR-938) were associated with intestinal-type GC, and rs4822739:C>G (miR-548j) and rs1439619:T>G (miR-3175) with TNM I-II stage. The polymorphisms rs6149511:T> TGAAGGGCTCCA (miR-6891), rs404337:G>A (miR-8084), and rs1439619:T>G (miR-3175) were identified among H.pylori-infected GC patients and rs7500280:T>C (miR-4719) and rs1439619:T>G (miR-3175) were found among H. pylori cagPAI+ infected GC cases. Prediction analysis suggests that seven polymorphisms could alter the secondary structure of the miRNA, and the other one is located in the seed region of miR-938. Targets of miRNAs are enriched in GC pathways, suggesting a possible biological effect. In this study, we identified seven novel associations and replicated one previously described in Caucasian population. These findings contribute to the understanding of miRNA genetic polymorphisms in the GC pathogenesis.

Inhibition of MicroRNA-302c on Stemness of Colon Cancer Stem Cells via the CARF/Wnt/β-Catenin Axis

BACKGROUND

Even though the relevance of microRNA (miR)-302c has been studied, little is known about its involvement in colon cancer (CC).

AIMS

Our aim here was to investigate the role of miR-302c in the cancer stem cells (CSCs) of CC.

METHODS

Firstly, the CSCs were screened out from cultured SW1116 and SW480 cells by flow cytometry, and the differentially expressed miRNAs in cell were obtained by microarray analysis. The expression of miR-302c, collaborator of ARF (CARF), and Wnt/β-catenin-related genes in CSCs was determined by means of RT-qPCR and Western blot. A dual-luciferase reporter assay was conducted to authenticate the binding relationship between miR-302c and CARF. Proliferation, migration, invasion, sphere formation as well as apoptosis of CSCs were assessed by cell counting kit-8, Transwell assay, sphere formation assay as well as flow cytometric analysis, respectively. The roles of miR-302c and CARF in tumor growth were determined in vivo.

RESULTS

The expression of miR-302c in CC cells was reduced versus that in normal cells. The overexpression of miR-302c weakened the stemness, proliferation, invasion, and migration abilities while induced apoptosis of CSCs in CC. Also, miR-302c reduced tumor size and weight in mice, accompanied with lowered CARF expression. The mechanistic analysis manifested that miR-302c bound to CARF and suppressed its expression and disrupted the Wnt/β-catenin signaling.

CONCLUSION

This study offers a novel characterization of miR-302c function in CSCs in CC, which may be beneficial to the development of capable therapeutic options for CC.

MicroRNA-302s Might Regulate ARL4C-Mediated Gastric Cancer Progression via p53 Signaling: Bioinformatics Analysis and Experiments Validation

Background

Our previous studies demonstrate that ARL4C is the most critical clinical biomarker for gastric cancer (GC) patients among ARL family members (ARLs) and functions as an oncogene in GC. However, its underlying mechanisms in GC need to be further illustrated. In this study, we aim to explore the upstream and downstream molecular mechanisms of ARL4C in GC cells.

Methods

The genetic alteration of ARL4C in GC is analyzed by cBioPortal database. Potential ARL4C-targeted microRNAs (miRs) are predicted by three databases. The high-throughput RNA sequencing is performed to explore the underlying mechanisms of ARL4C in GC cells. The effects of predicted microRNAs on ARL4C, the RNA-sequencing results validation and the biological functions of ARL4C in GC cells are illustrated by in vitro experiments.

Results

Genetic analyses indicate that ARL4C is significantly upregulated in GC, which is not caused by gene amplification. MicroRNAs prediction shows the high relevance between ARL4C and miR-302 members. Moreover, miR-302c or miR-302d transfection reduces ARL4C protein expression in GC cells. Based on the high-throughput RNA sequencing of ARL4C-knockdown cells, enrichment analyses demonstrate that ARL4C is closely related to cell growth and involved in p53 signaling. Moreover, there are strong gene–gene interactions between ARL4C and genes in p53 signaling, and ARL4C downregulation could inhibit the protein expression of MDM2, a critical gene in p53 pathway. Further functional experiments demonstrate that ARL4C silencing leads to cell cycle arrest and increased cell apoptosis in AGS and MKN45 cells.

Conclusion

Our data suggest that miR-302c and miR-302d may function as the upstream regulators of ARL4C. And, ARL4C might promote GC cell cycle progression via regulating p53 signaling. Our findings provide novel insights into the key role of ARL4C and the underlying mechanisms in GC progression, thus facilitating the development of ARL4C-targeted therapy.

miRNAs and Biomarkers in Testicular Germ Cell Tumors: An Update

Testicular germ cell tumors (TGCTs) are the leading form of solid cancer and death affecting males between the ages of 20 and 40. Today, their surgical resection and chemotherapy are the treatments of first choice, even if sometimes this is not enough to save the lives of patients with TGCT. As seen for several tumors, the deregulation of microRNAs (miRNAs) is also a key feature in TGCTs. miRNAs are small molecules of RNA with biological activity that are released into biological fluids by testicular cancer cells. Their presence, therefore, can be detected and monitored by considering miRNAs as diagnostic and prognostic markers for TGCTs. The purpose of this review is to collect all the studies executed on miRNAs that have a potential role as biomarkers for testicular tumors.

Expressions of miR-302a, miR-105, and miR-888 Play Critical Roles in Pathogenesis, Radiotherapy, and Prognosis on Rectal Cancer Patients: A Study From Rectal Cancer Patients in a Swedish Rectal Cancer Trial of Preoperative Radiotherapy to Big Database Analyses

Differential expressions and functions of various micoRNAs (miRNAs) have been intensively studied in both colon and rectal cancers. However, the importance of miRNAs on radiotherapy (RT) response and clinical outcome in rectal cancer patients remains unclear. In this study, we used real-time polymerase chain reaction to examine the expressions of miR-302a, miR-105, and miR-888 in normal mucosa and cancer tissue from rectal cancer patients with and without preoperative RT. The biological function of miR-302a, miR-105, and miR-888 expression was further analyzed and identified through the public databases: TCGA (The Cancer Genome Atlas) and GEPIA (Gene Expression Profiling Interactive Analysis). The results showed that the expression of miR-105 in rectal cancer was higher than that in normal mucosa in RT (P = 0.042) and non-RT patients (P = 0.003) and was associated with mucinous histological type (P = 0.004), COX-2 (P = 0.042), and p73 expression (P = 0.030). The expression of miR-302a was shown more frequently in cancers with necrosis (P = 0.033) and with WRAP53 expression (P = 0.015), whereas miR-888 expression occurred more frequently in tumors with protein the expression of survivin (P = 0.015), AEG-1 (astrocyte elevated gene-1) (P = 0.003), and SATB1 (special AT-rich sequence binding protein 1) (P = 0.036). Moreover, TargetScan also predicted AEG-1 and SATB1 as putative targets for miR-888. The miRNA-gene network analysis showed that ABI2 was associated with all the three miRNAs, with lower expression and good diagnostic value in rectal cancers. The TCGA database demonstrated the association of miR-105 expression with high carcinoembryonic antigen level (P = 0.048). RT reduced the expressions of miR-302a, miR-105, and miR-888. Prognostic analysis showed that miR-888 expression was independently associated with worse survival of patients without RT [overall survival, P = 0.001; disease-free survival, P = 0.009]. Analysis of biological function revealed that the protein serine/threonine kinase activity and PI3K-AKT signaling pathway were the most significantly enriched functions and pathways, respectively. Our findings suggest that miR-105 is involved in rectal cancer pathogenesis and miR-888 is associated with prognosis. MiR-302a, miR-105, and miR-888 have potential influence on the pathogenesis, RT, and prognosis of rectal cancer.

RACK1 promotes miR-302b/c/d-3p expression and inhibits CCNO expression to induce cell apoptosis in cervical squamous cell carcinoma

Background

Cervical squamous cell carcinoma (CSCC) is one of the main causes of cancer-related deaths in women worldwide. The present study was conducted with the main objective of determining the potential role of receptor for activated protein kinase C1 (RACK1) in CSCC through regulation of microRNA (miR)-302b/c/d-3p and Cyclin O (CCNO).

Methods

The expression of RACK1, miR-302b/c/d-3p and CCNO in CSCC tissues and cells was measured by RT-qPCR and Western blot analysis. The interaction among RACK1, miR-302b/c/d-3p, and CCNO was determined by dual luciferase reporter assay. Subsequently, effects of RACK1, miR-302b/c/d-3p and CCNO on CSCC cell cycle entry, proliferation and apoptosis were investigated with the use of flow cytometry, EdU, and TUNEL assays. Furthermore, mouse xenograft model of CSCC cells was established to verify the function of RACK1 in vivo.

Results

RACK1 and miR-302b/c/d-3p were down-regulated and CCNO was overexpressed in CSCC. CCNO was identified as the target of miR-302b/c/d-3p. Importantly, overexpressed miR-302b-3p, miR-302c-3p or miR-302d-3p or RACK1 enhanced the apoptosis and suppressed the proliferation of CSCC cells in vitro, while inhibiting tumor growth in vivo by targeting CCNO.

Conclusions

On all accounts, overexpressed RACK1 could dampen the progression of CSCC through miR-302b/c/d-3p-mediated CCNO inhibition.

Role of miR-302/367 cluster in human physiology and pathophysiology

MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate target mRNAs at the post-transcriptional level. Increasing evidence shows the involvement of miRNAs in diverse biological processes. miR-302/367 cluster is highly conserved among vertebrates and made up of five members, including miR-367, miR-302a, miR-302b, miR-302c and miR-302d. miR-302/367 cluster plays an important role in cell proliferation, differentiation and reprogramming, affecting the development of tumor, cardiovascular system, nervous system and immune system. In this review, we will summarize the role of miR-302/367 cluster in embryonic stem cells and induced pluripotent stem cells and try to point out its relationship with tumors, cardiovascular system, nervous system and immune system.

HOXA-AS2 promotes type I endometrial carcinoma via miRNA-302c-3p-mediated regulation of ZFX

Background

HOXA cluster antisense RNA2 (HOXA-AS2), a long-chain non-coding RNA, plays an important role in the behavior of various malignant tumors. The roles of HOXA-AS2 in endometrial cancer remain unclear.

Methods

We test expression levels of HOXA-AS2, miRNA-302c-3p, the transcription factor zinc finger X-chromosomal protein (ZFX), and the chitinase-like protein YKL-40 in endometrial carcinoma by qRT-PCR and western blotting. Luciferase reporter and qRT-PCR assays were conducted to identify potential binding sites of HOXA-AS2 to miRNA-302c-3p. Cell cycle, migration and invasion ability of endometrial cancer cells were investigated using flow-cytometric analysis, CCK-8 and transwell assays, respectively.

Results

HOXA-AS2 levels were significantly increased in endometrial cancer specimens compared to normal endometrial specimens. Upregulated HOXA-AS2 promoted invasion and proliferation of type I endometrial cancer cells. HOXA-AS2 silenced miRNA-302c-3p by binding to it. MiRNA-302c-3p negatively regulates ZFX and YKL-40. Thus HOXA-AS2 promotes the development of type I endometrial cancer via miRNA-302c-3p-mediated regulation of ZFX.

Conclusions

These findings suggest that HOXA-AS2 can act as a new therapeutic target for type I endometrial cancer.

Regulatory mechanism of tumor suppressor gene miR-302b in malignant tumors

MicroRNAs are a class of endogenous non-coding RNA molecules that regulate the translation of proteins. They play important regulatory roles in the growth, development, and aging of organisms, as well as cell proliferation, differentiation, apoptosis, and even cancer. miR-302b can participate in the regulation of the expression of a variety of genes, and functions as a tumor suppressor gene in the occurrence, development, invasion, and metastasis of malignant tumors. This article discusses the expression of miR-302b in malignant tumors and its biological functions and molecular mechanism.

Non-Coding microRNAs as Novel Potential Tumor Markers in Testicular Cancer

Testicular cancer is an important disease with increasing incidence and a high burden of morbidity and mortality in young men worldwide. Histological examination of the testicular tissue after orchiectomy plays an important role alongside patient history, imaging, clinical presentation and laboratory parameters. Surgical procedures and chemotherapeutic treatment provide a high chance of cure in early stages, though some patients in advanced stages belonging to a poor risk group experience cancer-related death. Though conventional serum-based tumor markers, including α-fetoprotein (AFP), the β-subunit of human chorionic gonadotropin (β-hCG), and lactate dehydrogenase (LDH), are useful as prognostic and diagnostic biomarkers, unfortunately, these tumor markers only have a sensitivity of about 60%, and in pure seminoma even lower with about 20%. Therefore, the development of new tumor markers is an important and intensively ongoing issue. The analysis of epigenetic modification and non-coding RNA microRNAs (miRNAs) are carrying most promising potential as tumor markers in future. miRNAs are small RNAs secreted by testicular tumor cells and circulate and be measurable in body fluids. In recent years, miRNAs of the miR-371-373 cluster in particular have been identified as potentially superior tumor markers in testicular cancer patients. Studies showed that miR-371a-3p and miR-302/367 expression significantly differ between testicular tumors and healthy testicular tissue. Several studies including high prospective multi-center trials clearly demonstrated that these miRNAs significantly exceed the sensitivity and specificity of conventional tumor markers and may help to facilitate the diagnosis, follow-up, and early detection of recurrences in testicular cancer patients. In addition, other miRNAs such as miR-223-3p, miR-449, miR-383, miR-514a-3p, miR-199a-3p, and miR-214 will be discussed in this review. However, further studies are needed to identify the value of these novel markers in additional clinical scenarios, including the monitoring in active surveillance or after adjuvant chemotherapy, but also to show the limitations of these tumor markers. The aim of this review is to give an overview on the current knowledge regarding the relevance of non-coding miRNAs as biomarkers in testicular cancer.

Application of the microRNA-302/367 cluster in cancer therapy

As a novel class of noncoding RNAs, microRNAs (miRNAs) can effectively silence their target genes at the posttranscriptional level. Various biological processes, such as cell proliferation, differentiation, and motility, are regulated by miRNAs. In different diseases and different stages of disease, miRNAs have various expression patterns, which makes them candidate prognostic markers and therapeutic targets. Abnormal miRNA expression has been detected in numerous neoplastic diseases in humans, which indicates the potential role of miRNAs in tumorigenesis. Previous studies have indicated that miRNAs are involved in nearly the entire process of tumor development. MicroRNA‐302a, miR‐302b, miR‐302c, miR‐302d, and miR‐367 are members of the miR‐302/367 cluster that plays various biological roles in diverse neoplastic diseases by targeting different genes. These miRNAs have been implicated in several unique characteristics of cancer, including the evasion of growth suppressors, the sustained activation of proliferative signaling, the evasion of cell death and senescence, and the regulation of angiogenesis, invasion, and metastasis. This review provides a critical overview of miR‐302/367 cluster dysregulation and the subsequent effects in cancer and highlights the vast potential of members of this cluster as therapeutic targets and novel biomarkers.

LncRNA SBF2-AS1 affects the radiosensitivity of non-small cell lung cancer via modulating microRNA-302a/MBNL3 axis

Background: Long non-coding RNAs (lncRNAs) have been reported to participate in many diseases including non-small cell lung cancer (NSCLC), thus our objective was to investigate the impact of lncRNA SBF2-AS1 modulating microRNA-302a (miR-302a) expression on radiosensitivity of NSCLC.Methods: The expression of SBF2-AS1, miR-302a and muscleblind-like 3 (MBNL3) in NSCLC tissues of the radiotherapy-sensitive and radiotherapy-resistant groups was tested. The radiosensitivity of parent and resistant strains (NCI-H1299 and NCI-H1299_R cells) was detected. Further, cells were treated with si-SBF2-AS1 and miR-302a mimics to determine their roles in proliferation and apoptosis of parent strain and resistant strain cells as well as transfected cells. The in-vivo growth capacity of the cells and the effect of radiotherapy on tumor size of NSCLC were detected.Results: Up-regulated SBF2-AS1 and MBNL3 and down-regulated miR-302a in NSCLC tissues of the radiotherapy resistant group. Overexpression of SBF2-AS1 and MBNL3 and low expression of miR-302a were witnessed in NCI-H1299_R cells. Down-regulated SBF2-AS1 or up-regulated miR-302a suppressed the proliferation while boosted the apoptosis of NCI-H1299 cells and decreased the radioresistance of the NCI-H1299_R cells. Silencing SBF2-AS1 or up-regulating miR-302a restrained tumor growth in vivo.Conclusion: Our study presents that high expression of miR-302a or inhibition of SBF2-AS1 can enhance the radiosensitivity and apoptosis of NSCLC cells through downregulation of MBNL3, which is a therapeutic target for NSCLC.

miR-1294 alleviates epithelial-mesenchymal transition by repressing FOXK1 in gastric cancer

BACKGROUND

MicroRNAs (miRNAs) have been reported play critical roles in regulating tumor development and progression.

OBJECTIVE

This study aimed to investigate the potential effect of miR-1294 in gastric cancer (GC).

METHODS

Reverse transcription quantitative polymerase chain reaction (RT-PCR) were performed to verify the expression level of miR-1294 and Forkhead box protein K1 (FOXK1). Overall survival data of miR-1294 for GC was analysed by log-rank test. Targetscan was used to screen potential target gene of miR-1294. Dual luciferase assay was assessed to investigate the relationship between miR-1294 and FOXK1. The miR-1294 overexpression and knockdown were designed to study the biological function of miR-1294. The migration and invasion of GC cell lines were investigated by wound healing and transwell assays. Western blotting were performed to verify the expression level of epithelial marker, mesenchymal markers and FOXK1. Overexpression of FOXK1 was designed to study the rescue effects of FOXK1 in SGC7901 cell.

RESULTS

miR-1294 was found downregulated in GC patients and cell lines. A higher miR-1294 expression showed a significant longer overall survival than those with a lower miR-1294 expression. miR-1294 directly targets FOXK1 and regulates the expression of FOXK1. In addition, miR-1294 regulates epithelial-mesenchymal transition (EMT) by inhibiting FOXK1 in GC cells and it can be rescued by overexpression of FOXK1.

CONCLUSION

miR-1294 alleviates EMT process in GC by targeting FOXK1.

[Clinical Application of Plasma miR-34b-3p and miR-302a-5p in the Diagnosis of Non-small Cell Lung Cancer]

BACKGROUND

MicroRNA is a kind of single-stranded non-coding RNA whose length is about 22 nucleotides and its abnormal expression is related to disease closely. This study is aiming to explore the relative expression of miR-34b-3p and miR-302a-5p in the plasma of non-small cell lung cancer (NSCLC) patients and its clinical value.

METHODS

The levels of miR-34b-3p and miR-302a-5p in plasma were detected by real-time polymerase chain reaction (RT-PCR) in 86 patients with NSCLC, 64 patients with pulmonary tuberculosis (PTB) and 39 healthy subjects. Analyze their value in diagnosing NSCLC by contrasting and combining carcino-embryonic antigen (CEA), neuron-specific enolase (NSE), and cytokeratin 19 fragments 21-1 (CYFRA21-1).

RESULTS

The levels of plasma miR-34b-3p and miR-302a-5p in NSCLC group were significantly higher than those in the PTB group and the healthy group (P<0.05). In patients with NSCLC, the levels of plasma miR-34b-3p was correlated with the diameter of tumor (P<0.01). When using one plasma marker to diagnose NSCLC, miR-302a-5p had the highest sensitivity (82.6%) and CEA had the highest specificity (81.6%). While combined two plasma markers, miR-34b-3p+miR-302a-5p had the highest sensitivity (80.2%) and miR-34b-3p+CEA had the highest specificity (81.4%). As detected multiple markers, miR-302a-5p+NSE+CYFRA21-1 had the highest sensitivity (81.4%) and miR-34b-3p+CEA+NSE had the highest specificity (90.3%). The combination of miR-34b-3p, miR-302a-5p and CEA obtained the highest area under the curve (AUC), which was 0.832. Logistic regression model indicated that miR-34b-3p was independent risk factor for NSCLC compared to control groups.

CONCLUSIONS

Plasma miR-34b-3p and miR-302a-5p could be used as biological markers for the diagnosis of NSCLC.

Association and in silico investigations of miR-302c insertion/deletion variant as a novel biomarker with susceptibility to gastric cancer

Gastric cancer (GC) is the fifth most prevalent malignant tumor and the third most frequent cause of cancer mortality worldwide. rs199971565 is an insertion/deletion (INDEL) located in microRNA-302c (miR-302c) seed site, which may affect its function and biogenesis. There is no genetic association study investigating this INDEL with any disease till now. Thus, the current study was conducted to investigate the association of rs199971565 with susceptibility to GC in an Iranian population. In addition, in silico studies were performed to reveal the possible functional significance of this INDEL. A total of 378 subjects were genotyped through amplification refractory mutation system PCR (ARMS-PCR) after DNA extraction from peripheral blood by the salting out procedure. Also, in silico analyses were performed through databases and web tools including MiRNASNP V2.0, miRWalk V2.0, miRTarBase, DAVID V6.8, RNAfold, PHDcleave, miRmap, and STarMir. Results revealed that there was an association between rs199971565 and the incidence risk of GC under a recessive (P = .04, odds ratio [OR] = 18.73; 95% confidence interval [CI] = 1.07-326.95) model of inheritance. Also, compared to the Ins allele, the Del allele significantly increased the risk of GC (P = .01, OR = 2.02; 95% CI = 1.11-3.66). Further analyses showed no significant association in age and sex between two study groups (P = .216 and P = .798, respectively). In conclusion, for the first time, this study indicated the association and in silico investigations of rs199971565 and suggested it as a novel INDEL biomarker located in the seed site of miR-302c, which may have crucial roles in the susceptibility to GC and its incidence risk.

The Role of MicroRNAs in the Regulation of Gastric Cancer Stem Cells: A Meta-Analysis of the Current Status

Gastric cancer (GC) remains one of the major causes of cancer-related mortality worldwide. As for other types of cancers, several limitations to the success of current therapeutic GC treatments may be due to cancer drug resistance that leads to tumor recurrence and metastasis. Increasing evidence suggests that cancer stem cells (CSCs) are among the major causative factors of cancer treatment failure. The research of molecular CSC mechanisms and the regulation of their properties have been intensively studied. To date, molecular gastric cancer stem cell (GCSC) characterization remains largely incomplete. Among the GCSC-targeting approaches to overcome tumor progression, recent studies have focused their attention on microRNA (miRNA). The miRNAs are short non-coding RNAs which play an important role in the regulation of numerous cellular processes through the modulation of their target gene expression. In this review, we summarize and discuss recent findings on the role of miRNAs in GCSC regulation. In addition, we perform a meta-analysis aimed to identify novel miRNAs involved in GCSC homeostasis.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles Inhibit Endometrial Cancer Cell Proliferation and Migration through Delivery of Exogenous miR-302a

MicroRNAs (miRNAs) are potential therapeutic targets in endometrial cancer, but the difficulties associated with their delivery to tumor target cells have hampered their applications. Human umbilical cord mesenchymal stem cells (hUCMSCs) have a well-recognized tumor-homing ability, emphasizing the capacity of tumor-targeted delivery of extracellular vesicles. hUCMSCs release extracellular vesicles rich in miRNAs, which play a vital role in intercellular communication. The purpose of this study was to verify a potential tumor suppressor microRNA, miR-302a, and engineered hUCMSC extracellular vesicles enriched with miR-302a for therapy of endometrial cancer. Here, we observed that miR-302a was significantly downregulated in endometrial cancer tissues when compared with adjacent tissues. Overexpression of miR-302a in endometrial cancer cells robustly suppressed cell proliferation and migration. Meanwhile, the proliferation and migration were significantly inhibited in endometrial cancer cells when cultured with miR-302a-loaded extracellular vesicles derived from hUCMSCs. Importantly, our data showed that engineered extracellular vesicles rich in miR-302 significantly inhibited the expression of cyclin D1 and suppressed AKT signaling pathway in endometrial cancer cells. These results suggested that exogenous miR-302a delivered by hUCMSC-derived extracellular vesicles has exciting potential as an effective anticancer therapy.

miR-302a inhibits human HepG2 and SMMC-7721 cells proliferation and promotes apoptosis by targeting MAP3K2 and PBX3

Hepatocellular carcinoma (HCC) is the most common liver cancer and has a poor prognosis. miR-302a is an important regulator of tumor occurrence and deterioration, while MAP3K2 and PBX3 genes are involved in cancer cell proliferation and apoptosis. In this study, the expression of miR-302a and MAP3K2/PBX3 were evaluated by qPCR in liver cancer cell lines. Next, the target relationship between miR-302a and MAP3K2/PBX3 was verified using luciferase assays. Meanwhile, the expression correlation between miR-302a and target genes was analyzed in cancer tissue and para-cancerous tissue. In addition, an increased miR-302a level in HepG2 cells and SMMC-7721 cells were achieved through transfection with miR-302a mimics, and the effects on HepG2 cell and SMMC-7721 cell proliferation, apoptosis and MAPK pathways were determined using MTT, flow cytometry, qPCR and western blot assays. The results showed that liver cancer cell lines exhibited low miR-302a expression and MAP3K2 and PBX3 were confirmed to be the target genes of miR-302a. Meanwhile, the HE results showed that cells became enlarged with loose cytoplasm and formed balloon-like lesions in HCC specimens and we found a significant negative correlation between miR-302a and MAP3K2/PBX3 expression. In addition, treatment with miR-302a mimics inhibited HepG2 cells and SMMC-7721 cells proliferation and increased the apoptosis rate. Further research revealed that the MAPK key factors p-p38, p-ERK1/2 and p-JNK were significantly reduced in miR-302a transfected cells and MAP3K2/PBX3 silenced cells. Besides, MAP3K2 and PBX3 overexpression in miR-302a mimics-treated cells exerted the opposite effects. In conclusion, miR-302a inhibited proliferation and promoted apoptosis in human hepatoma cells by targeting MAP3K2 and PBX3.

MicroRNA-302a-3p suppresses hepatocellular carcinoma progression by inhibiting proliferation and invasion

Background

Involvement of microRNAs in tumor development and their potential as prognostic biomarkers had been well acknowledged. However, the expression, clinical significance, and functional mechanisms of microRNA (miR)-302a-3p in hepatocellular carcinoma (HCC) have not been reported.

Patients and methods

Real-time quantitative polymerase chain reaction was used to evaluate the expression of miR-302a-3p in 111 HCC tissues and adjacent normal liver tissues. Its association with clinicopathological characteristics was analyzed by the chi-square test. The Kaplan–Meier univariate survival analysis and multivariate Cox regression analysis were used to identify the clinical significance of miR-302a-3p in the overall survival (OS) of HCC patients. Transfection of miR-302a-3p mimics into HepG2 and Huh7 HCC cell lines was conducted to reveal its underlying mechanism in regulating HCC progression.

Results

miR-302a-3p expression was significantly decreased in HCC tissues compared with that in paired adjacent normal liver tissues (P=0.005). miR-302a-3p expression was correlated with tumor number (P=0.003), tumor size (P<0.001), and tumor TNM stage (P=0.028). The Kaplan–Meier survival analysis showed that patients in the high miR-302a-3p expression group had a better OS than those in the low miR-302a-3p expression group (P=0.002). Multivariate analysis confirmed that miR-302a-3p expression can be used as an independent predictor for HCC prognosis (HR=0.480, 95% CI=0.249–0.894, P=0.039). Proliferation, migration, and invasion capacities were all decreased in cells transfected with miR-302a-3p mimics. Moreover, our data showed a direct effect of miR302a-3p on inhibiting the expression and signaling of PRKACB in HCC cells.

Conclusions

miR-302a-3p serves as a tumor suppressor in HCC progression by directly inhibiting tumor proliferation and invasion, and its low expression is a potential biomarker for predicting a poor prognosis of HCC patients.

MiR-302b regulates cell functions and acts as a potential biomarker to predict recurrence in bladder cancer

BACKGROUND

Bladder cancer is the most common urogenital tumor with substantial morbidity, high recurrence rate and mortality. miRNAs, a class of endogenous noncoding RNA, were found to involve in the genesis, maintenance and metastasis of cancer. Genomic profiling revealed that miR-302b is down-regulated in bladder cancer while its functions in bladder cancer remain to be ascertained.

METHODS

Cell functional assays including wound healing assay, CCK-8 assay, Transwell assay and flow cytometry assay were performed to clarify the functions of miR-302b expression in cell proliferation, migration, invasion and apoptosis in BC. Furthermore, RT-qPCR was performed to study the expression of miR-302b in bladder cancer tissues and the prognostic value of altered miR-302b expression with 48 formalin-fixed paraffin-embedded bladder urothelial carcinoma samples.

RESULTS

The results of RT-qPCR demonstrated that expression level of miR-302b was significantly reduced in bladder cancer tissues and cell lines. The cells after transfected with miR-302b mimic showed lower mobility, lower proliferation and increased apoptosis, while opposite results were obtained after inhibiting the expression of miR-302b. The prognosis analysis demonstrated that the patients with low expression of miR-302b experienced high risks of recurrence.

CONCLUSIONS

The results of our study demonstrate that miR-302b regulates cell functions and acts as a potential biomarker to predict recurrence in bladder cancer.

The tumor suppressive miR-302c-3p inhibits migration and invasion of hepatocellular carcinoma cells by targeting TRAF4

MicroRNAs (miRNAs) have been recognized as key regulators of tumorigenesis and progression. Serum miR-302c-3p expression is prominently deregulated in HCV-related hepatocellular carcinoma (HCC). However, the expression of miR-302c-3p and its functional role in HBV-related HCC are rarely investigated. In this study, we found that the expression levels of miR-302c-3p were prominently down-regulated in HCC tissues compared to matched tumor-adjacent tissues. Moreover, miR-302c-3p under-expression was detected in HCC cell lines compared to a normal hepatic cell line LO2. Low miR-302c-3p expression was positively correlated with multiple tumor nodes, venous infiltration and advanced TNM tumor stage of HCC patients. Notably, our follow up data and TCGA data demonstrated that low miR-302c-3p expression predicted a poor survival of HCC patients. Functionally, miR-302c-3p overexpression inhibited migration and invasion of MHCC97H cells in vitro. Additionally, miR-302c-3p knockdown showed an opposite effect on these metastatic behaviors of HepG2 cells. MiR-302c-3p negatively regulated tumor necrosis factor receptor associated factor 4 (TRAF4) abundance by directly targeting 3'-UTR of TRAF4 mRNA. The expression of TRAF4 was up-regulated in HCC tissues. The level of TRAF4 mRNA was inversely correlated with miR-302c-3p expression in HCC specimens. Mechanistically, miR-302c-3p restrained AKT-mediated epithelial-mesenchymal transition (EMT) in HCC cells. Importantly, TRAF4 restoration reversed the inhibitory effect of miR-302c-3p on AKT-induced EMT and HCC cell metastasis. MK2206, an AKT inhibitor, inhibited miR-302c-3p knockdown-induced EMT in HepG2 cells. In summary, these results indicate that miR-302c-3p exhibits a tumor suppressive role in HCC by targeting TRAF4. Inhibition of miR-302c-3p/TRAF4 axis may serve as a therapeutic target for HCC.

MicroRNA-302c represses epithelial-mesenchymal transition and metastasis by targeting transcription factor AP-4 in colorectal cancer

MicroRNAs (miRNAs) contribute to tumorigenesis and progression via acting as tumor suppressors or oncogenes in human cancer. Aberrant expression of miR-302c has been reported in various types of cancer except colorectal cancer (CRC). Thus, our study was aimed to verify the expression of miR-302c and its functional role in CRC. We found a significant reduced expression of miR-302c in CRC tissues compared to tumor-adjacent tissues. Low miR-302c level was remarkably correlated with deeper tumor invasion, lymph node metastasis and advanced TNM stage. Importantly, low miR-302c expression was identified as an independent indicator for poor prognosis of CRC patients. Overexpression of miR-302c repressed migration and invasion capacities of SW620 and SW480 cells in vitro. Mechanistically, miR-302c inversely regulated transcription factor AP4 (TFAP4) abundance in both SW620 and SW480 cells, and it negatively correlated with TFAP4 mRNA expression in CRC samples. Herein, TFAP4, a regulator of epithelial-mesenchymal transition (EMT), was recognized as a direct target gene of miR-302c in CRC. Otherwise, miR-302c overexpression increased E-cadherin expression and reduced the levels of Vimentin and SNAI1, suggesting an inhibitory effect of miR-302c on EMT of CRC cells. Notably, our findings established that the EMT and metastasis of Caco-2 cells were enhanced by miR-302c knockdown, and subsequently reversed by TFAP4 silencing. Collectively, these data indicate that miR-302c represses EMT and CRC metastasis possibly by targeting TFAP4, and it may serve as a potential prognostic factor and therapeutic target for CRC.