MicroRNA-873 acts as a tumor suppressor in esophageal cancer by inhibiting differentiated embryonic chondrocyte expressed gene 2

MicroRNAs in esophageal squamous cell carcinoma: Application in prognosis, diagnosis, and drug delivery

MicroRNAs (miRNAs) play a vital role in various cell biology processes, including cancer formation. These small non-coding RNAs could function as diagnostic and prognostic markers. They may involve esophageal squamous cell carcinoma (ESCC) and distinctive miRNA expression profiles; they are also known as therapeutic targets in human diseases. Therefore, in this study, the function of miRNAs was reviewed regarding the prognosis and diagnosis of ESCC. The changes in miRNAs before and after cancer therapy and the effects of miRNAs on chemo-susceptibility patterns were also investigated. MiRNA delivery systems in ESCC were also highlighted, providing a perspective on how these systems can improve miRNA efficiency.

Tumor Suppressor microRNAs in Gastrointestinal Cancers: A Mini-Review

BACKGROUND

Gastrointestinal (GI) cancer is associated with a group of cancers affecting the organs in the GI tract, with a high incidence and mortality rate. This type of cancer development involves a series of molecular events that arise by the dysregulation of gene expressions and microRNAs (miRNAs).

OBJECTIVES

This mini-review focuses on elucidating the mechanism of tumor suppressor miRNA-mediated oncogenic gene silencing, which may contribute to a better understanding of miRNA-mediated gene expression regulation of cell cycle, proliferation, invasion, and apoptosis in GI cancers. In this review, the biological significance of tumor suppressor miRNAs involved in gastrointestinal cancers is briefly explained.

METHODS

The articles were searched with the keywords 'miRNA', 'gastrointestinal cancers', 'esophageal cancer', 'gastric cancer', 'colorectal cancer', 'pancreatic cancer', 'liver cancer', and 'gall bladder cancer' from the Google Scholar and PubMed databases. A total of 71 research and review articles have been collected and referred for this study.

RESULTS

This review summarises recent research enhancing the effectiveness of miRNAs as novel prognostic, diagnostic, and therapeutic markers for GI cancer treatment strategies. The expression pattern of various miRNAs has been dysregulated in GI cancers, which are associated with proliferation, cell cycle regulation, apoptosis, migration, and invasion.

CONCLUSION

The role of tumor suppressor miRNAs in the negative regulation of oncogenic gene expression was thoroughly explained in this review. Its potential role as a microRNA therapeutic candidate is also discussed. Profiling and regulating tumor suppressor miRNA expression in gastrointestinal cancers using miRNA mimics could be used as a prognostic, diagnostic, and therapeutic marker, as well as an elucidating molecular therapeutic approach to tumor suppression.

Circular RNA hsa_circ_0000277 promotes tumor progression and DDP resistance in esophageal squamous cell carcinoma

Background

Circular RNAs (circRNAs) are well-known regulators of cancer progression and chemoresistance in various types of cancers. This study was performed to investigate the function of hsa_circ_0000277 in esophageal squamous cell carcinoma (ESCC).

Methods

RNA levels were analyzed via the reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell Counting Kit-8 (CCK-8) assay was applied to determine cell proliferation and half maximal inhibitory concentration (IC50) of cisplatin (DDP). Colony formation ability was evaluated by colony formation assay. Cell cycle and apoptosis were measured using flow cytometry. RNA immunoprecipitation (RIP), pull-down assay and dual-luciferase reporter assays were performed for target interaction analysis. The protein levels were determined through western blot. Xenograft models were established for researching hsa_circ_0000277 function in vivo.

Results

Hsa_circ_0000277 expression was increased in ESCC cells and tissues, and it had important clinical significance. Downregulation of hsa_circ_0000277 repressed ESCC cell proliferation, colony formation, cell cycle, and DDP resistance. Hsa_circ_0000277 acted as a microRNA-873-5p (miR-873-5p) sponge and Sry-related high-mobility group box 4 (SOX4) was validated as a target of miR-873-5p. Moreover, hsa_circ_0000277/miR-873-5p axis and miR-873-5p/SOX4 axis regulated ESCC cell progression and DDP resistance. Hsa_circ_0000277/miR-873-5p axis activated SOX4/Wnt/β-catenin signaling pathway. Hsa_circ_0000277 facilitated tumorigenesis and DDP resistance by miR-873-5p/SOX4 axis in vivo.

Conclusion

These findings unraveled that hsa_circ_0000277 promoted ESCC progression and DDP resistance via miR-873-5p/SOX4/Wnt/β-catenin axis, showing a specific molecular mechanism of carcinogenesis and chemoresistance in ESCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09241-9.

CircLPAR3 knockdown suppresses esophageal squamous cell carcinoma cell oncogenic phenotypes and Warburg effect through miR-873-5p/LDHA axis

BACKGROUND

Circular RNAs (circRNAs) have been identified to participate in regulating multiple malignancies. Herein, this study aimed to explore the clinical significance, biological function, and regulatory mechanisms of circRNA lysophosphatidic acid receptor 3 (circLPAR3) in esophageal squamous cell carcinoma (ESCC) cell malignant phenotypes and Warburg effect.

METHODS

The qRT-PCR and Western blot were used to detect the levels of genes and proteins. Glucose uptake and lactate production were detected to determine the Warburg effect. The effects of circLPAR3 on ESCC cell proliferation, apoptosis, and metastasis were evaluated by MTT, 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, wound healing, and transwell assays. The binding interaction between miR-873-5p and circLPAR3 or lactate dehydrogenase A (LDHA) was verified using dual-luciferase reporter and RIP assays. Xenograft mice models were established to conduct in vivo analysis.

RESULTS

CircLPAR3 is a stable circRNA and was increased in ESCC tissues and cells. Functionally, circLPAR3 knockdown suppressed ESCC cell Warburg effect, proliferation, metastasis, and induced apoptosis in vitro, and impeded xenograft tumor growth and Warburg effect in ESCC mice models. Mechanistically, circLPAR3 served as a sponge for miR-873-5p, which targeted LDHA. Moreover, circLPAR3 could regulate LDHA expression by sponging miR-873-5p. Thereafter, rescue experiments suggested that miR-873-5p inhibition reversed the anticancer effects of circLPAR3 silencing on ESCC cells. Furthermore, miR-873-5p overexpression restrained ESCC cell Warburg effect and oncogenic phenotypes, which were abolished by LDHA up-regulation.

CONCLUSION

CircLPAR3 knockdown suppressed ESCC cell growth, metastasis, and Warburg effect by miR-873-5p/LDHA axis, implying a promising molecular target for ESCC therapy.

MiR-873-5p: A Potential Molecular Marker for Cancer Diagnosis and Prognosis

miR-873 is a microRNA located on chromosome 9p21.1. miR-873-5p and miR-873-3p are the two main members of the miR-873 family. Most studies focus on miR-873-5p, and there are a few studies on miR-873-3p. The expression level of miR-873-5p was down-regulated in 14 cancers and up-regulated in 4 cancers. miR-873-5p has many targeted genes, which have unique molecular functions such as catalytic activity, transcription regulation, and binding. miR-873-5p affects cancer development through the PIK3/AKT/mTOR, Wnt/β-Catenin, NF-κβ, and MEK/ERK signaling pathways. In addition, the target genes of miR-873-5p are closely related to the proliferation, apoptosis, migration, invasion, cell cycle, cell stemness, and glycolysis of cancer cells. The target genes of miR-873-5p are also related to the efficacy of several anti-cancer drugs. Currently, in cancer, the expression of miR-873-5p is regulated by a variety of epigenetic factors. This review summarizes the role and mechanism of miR-873-5p in human tumors shows the potential value of miR-873-5p as a molecular marker for cancer diagnosis and prognosis.

LncRNA DCST1-AS1 Promotes Endometrial Cancer Progression by Modulating the MiR-665/HOXB5 and MiR-873-5p/CADM1 Pathways

Dysregulation of long noncoding RNA (lncRNA) is implicated in the initiation and progression of various tumors, including endometrial cancer (EC). However, the mechanism of lncRNAs in EC tumorigenesis and progression remains largely unexplored. In this work, we identified a novel lncRNA DC-STAMP domain-containing 1-antisense 1 (DCST1-AS1), which is highly upregulated and correlated with poor survival in EC patients. Overexpression of DCST1-AS1 significantly enhanced EC cell proliferation, colony formation, migration, and invasion in vitro and promoted tumor growth of EC in vivo. Mechanistically, DCST1-AS1 mediated EC progression by inducing the expression of homeobox B5 (HOXB5) and cell adhesion molecule 1 (CADM1), via acting as a competing endogenous RNA for microRNA-665 (miR-665) and microRNA-873-5p (miR-873-5p), respectively. In addition, we found that the expression of miR-665 and miR-873-5p was significantly downregulated, while HOXB5 and CADM1 expression levels were increased in EC tissues. Taken together, our findings support the important role of DCST1-AS1 in EC progression, and DCST1-AS1 may be used as a prognostic biomarker as well as a potential therapeutic target for EC.

Inhibition of DEC2 is necessary for exiting cell dormancy in salivary adenoid cystic carcinoma

Background

Patients were prone to have poor prognosis once dormant tumor cells being reactivated. However, the molecular mechanism of tumor cell dormancy remains poorly understood. This study aimed to investigate the function of DEC2 in the dormancy of salivary adenoid cystic carcinoma (SACC) in vitro and vivo.

Methods

The function of DEC2 in tumor dormancy of SACC was investigated in nude mice by establishing primary and lung metastasis model. Meanwhile, the interaction between hypoxia and SACC dormancy and the role of DEC2 were demonstrated through CoCl₂ induced hypoxia–mimicking microenvironments. Furthermore, the expression of DEC2 was detected by immunohistochemical staining in primary SACC samples with and without recurrence.

Results

In the primary SACC, DEC2 overexpression inhibited cell proliferation, increased cell population arrested in G0/G1 phase, and participated in dormancy regulation, which limited tumor growth. Intriguingly, in the model of lung metastasis, the level of DEC2 was reduced significantly and resulted in dormancy exit and growth resumption of SACC cells. Then, we found that DEC2 may associate with hypoxia in contributing to tumor dormancy, which might provide a possible cue to explain the different roles of DEC2 in primary and metastasis lesions. And overexpression of DEC2 induced dormancy and promoted migration and invasion through activating EMT program. Finally, DEC2 positive expression was shown to be significantly correlated with recurrence and dormancy of SACC patients.

Conclusions

These findings provide a novel insight into the role of DEC2 gene in tumor dormancy and metastasis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01956-0.

MiR-873-5p modulates progression of tongue squamous cell carcinoma via targeting SEC11A

OBJECTIVE

To explore the effect of miR-873-5p on proliferation, apoptosis, migration, and invasion of tongue squamous cell carcinoma (TSCC) by targeting SEC11A.

METHODS

Tongue squamous cell carcinoma tissues were collected and performed by qRT-PCR and Western blotting to determine the expression of miR-873-5p and SPC18. SCC9 and CAL-27 cells were transfected and divided into Mock, mimic NC, miR-873-5p mimic, SEC11A, and miR-873-5p mimic + SEC11A groups. Then, a series of experiments including cell count kit 8 (CCK-8), wound healing, Transwell, and flow cytometry were conducted. Besides, Western blotting was used to detect the expression of SPC18 and EGFR pathway-related proteins.

RESULTS

MiR-873-5p was downregulated while SPC18 was upregulated in TSCC, and miR-873-5p was negatively correlated with SPC18. Dual luciferase reporter gene assay confirmed SEC11A to be a target of miR-873-5p. Cell proliferation, migration, and invasion of SCC9 and CAL-27 cells in miR-873-5p mimic group were decreased with increased cell apoptosis, presenting with downregulations of SPC18 and EGFR pathway-related proteins, while cells in SEC11A group manifested totally different changes. Moreover, the inhibitory effect of miR-873-5p mimic on TSCC cell growth was abolished by SEC11A overexpression.

CONCLUSION

Overexpression of miR-873-5p may suppress cell proliferation, migration, and invasion, but facilitate apoptosis in TSCC via targeting SEC11A.

MiRNA-873-5p Acts as a Potential Novel Biomarker and Promotes Cervical Cancer Progression by Regulating ZEB1 via Notch Signaling Pathway

OBJECTIVE

Our group aimed to investigate the expression pattern of miRNA-873-5p in cervical cancer (CC) patients and its association with CC progression.

METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was applied for the examination of the expressions of miRNA-873-5p in both CC specimens and cell lines. The clinical significance of miRNA-873-5p was statistically analyzed. MTT, colony formation, Transwell and flow cytometry assays were used to detect cell proliferation, metastasis, and apoptosis changes of Hela and Siha cell line. Luciferase reporter assays and Western blots were utilized to identify the target genes of miRNA-873-5p. Western blot and RT-PCR were used to judge the dysregulation of Notch signaling.

RESULTS

Our results indicated that miRNA-873-5p expression was distinctly reduced in CC patients. Low miRNA-873-5p expressions were distinctly correlated with positively distant metastasis, The International Federation of Gynecology and Obstetrics (FIGO) stage and poor prognosis of CC patients. A functional assay using miRNA-873-5p mimics indicated that overexpression of miRNA-873-5p distinctly suppressed CC cells proliferation and metastasis, and promoted apoptosis. Bioinformatic assays revealed that miRNA-873-5p may target the 3'-UTR of ZEB1 and lead to the suppression of its translation, which was verified by the use of luciferase assays. Finally, overexpression of miRNA-873-5p suppressed the expressions of Jag1, Maml2 and Hey1.

CONCLUSION

Taken together, we firstly provided evidence that miRNA-873-5p expression was a poor favorable factor for CC patients, and the use of miRNA-873-5p may represent a and potential biomarker and promising therapeutic approach for CC.

Circular RNA circ_0004507 contributes to laryngeal cancer progression and cisplatin resistance by sponging miR-873 to upregulate multidrug resistance 1 and multidrug resistance protein 1

BACKGROUND

Circular RNAs (circRNAs) play critical roles in various types of cancer and chemosensitivity.

METHODS

The expression levels of circ_0004507 and microRNA-873 (miR-873) were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The interaction between circ_0004507 and miR-873 was predicted by circinteractome and verified by dual-luciferase reporter assay and RNA pull-down assay. Xenograft tumor model was established to confirm the biological role of circ_0004507 in vivo.

RESULTS

circ_0004507 was highly expressed and miR-873 was lowly expressed in laryngeal cancer tissues. circ_0004507 knockdown or miR-873 overexpression inhibited cell proliferation, migration and invasion, and increased apoptosis and cisplatin sensitivity in laryngeal cancer cells. miR-873 was identified as a direct target of circ_0004507. circ_0004507 interference inhibited tumor growth and promoted cisplatin sensitivity by upregulating miR-873 in vivo.

CONCLUSION

Knockdown of circ_0004507 inhibited laryngeal cancer progression and cisplatin resistance by sponging miR-873, providing a potential target for laryngeal cancer therapy.

MiR-25-3p targets PTEN to regulate the migration, invasion, and apoptosis of esophageal cancer cells via the PI3K/AKT pathway

BACKGROUND

Esophageal cancer (EC) is one of the most common malignant tumors of the digestive system. MiR-25-3p was proved to be a biomarker for the diagnosis and treatment of many cancers. MiR-25-3p was found to be high expressed in the blood of EC patients. The aim of the present study was to explore the effect of miR-25-3p and its target gene on EC.

METHODS

miR-25-3p expression in the blood of EC patients and EC cells was detected by RT-qPCR. The target of miR-25-3p was identified by bioinformatics and luciferase reporter assay. After transfection, cell viability, apoptosis, migration, and invasion were detected by MTT, flow cytometry, wound healing, and transwell assays, respectively. The expressions of PTEN, Bax, Bcl-2, cleaved Caspase-3, p-PI3K, PI3K, p-AKT, and AKT were detected by Western blot.

RESULTS

MiR-25-3p was high expressed in the blood of EC patients and EC cells. MiR-25-3p targeted PTEN and inhibited the expression of PTEN. MiR-25-3p mimic increased the viability, migration, invasion and the expressions of Bcl-2, and inhibited the apoptosis and the expression of Bax and cleaved caspase-3 in EC cells. MiR-25-3p mimic also enhanced the expressions of p-PI3K and p-AKT and the ratios of p-PI3K/PI3K and p-AKT/AKT in EC cells. PTEN overexpression not only had an opposite effect of miR-25-3p mimic, but also reversed the effect of miR-25-3p mimic on EC cells.

CONCLUSION

MiR-25-3p targeted PTEN to promote the migration and invasion, and inhibit apoptosis of EC cells via the PI3K/AKT pathway, which might provide a new therapeutic target for EC treatment.

Analysis of microRNA regulating cell cycle-related tumor suppressor genes in endometrial cancer patients

Endometrial cancer remains the most common malignancy of the female genital system in developed countries. Tumor suppressor genes are responsible for controlling the cells fate in the cell cycle and preventing cancerogenesis. Gene expression affects cancer progression and is modulated by microRNAs defined as both tumor suppressors and oncogenes. These molecules indirectly regulate multiple processes like cell proliferation, differentiation and apoptosis. The aim of this study was to analyze miRNAs expression that can regulate the activity of tumor suppressor genes related to the cell cycle in patients with endometrioid endometrial cancer. The study group consisted of 12 samples that met the inclusion criteria from a total of 48 obtained. The 12 samples were used to analyze microRNA expression. Complementary miRNAs were identified using TargetScan Database and statistical analysis. MicroRNAs were determined for the tumor suppressor genes: CYR61, WT1, TSPYL5, HNRNPA0, BCL2L1 and BAK1. All the miRNAs were complementary to the described target genes based on TargetScan Database. There were five miRNAs differentially expressed that can regulate tumor suppressor genes related to the cell cycle. The distinguished miRNAs: mir-340-3p, mir-1236-5p, mir-874-3p, mir-873-5p.2 and mir-548-5p were differentially expressed in endometrial cancer in comparison to the control. Among the distinguished miRNAs, the most promising is mir-874-3p, which may have an important role in endometrial adenocarcinoma proliferation.

The Depletion of ABI3BP by MicroRNA-183 Promotes the Development of Esophageal Carcinoma

Background

Esophageal cancer (EC), as a serious threat to human life and health, is one of the most common cancers around the world. Many studies have suggested that many microRNAs are involved in tumorigenesis and progression.

Methods

To search for a novel and promising predictive therapeutic target or biomarker to achieve the goal of the early diagnosis and treatment of EC, we used the EC cell lines Eca-109 and KYSE-150 and normal human esophageal epithelial cells (HEECs) to investigate the effect of ABI3BP on EC.

Results

We found that ABI family member 3 binding protein (ABI3BP) was downregulated in EC and suppressed the proliferation, activity, migration, and invasion of EC cells. ABI3BP was downregulated by miR-183, which plays the role of an oncogene.

Conclusion

ABI3BP and miR-183 can be considered potential biomarkers for the diagnosis of patients with EC and can be effective targets for antitumor therapy.

The tumor-suppressive role of microRNA-873 in nasopharyngeal carcinoma correlates with downregulation of ZIC2 and inhibition of AKT signaling pathway

Cancer stem cells (CSCs) are responsible for tumor initiation, relapse, and metastasis. Thus, residual CSCs after chemotherapy may result in poor prognosis for nasopharyngeal carcinoma (NPC). Emerging evidence suggests that differentially expressed microRNAs (miRNAs) regulate genes that carry out important functions in CSCs. Here we investigate the interaction of microRNA-873 (miR-873) with the Zic family member 2 (ZIC2) and the effects on downstream serine-threonine protein kinase (AKT) signaling pathway in CSCs in the context of NPC. Initially, microarray-based gene expression profiling identified ZIC2 as a key differentially expressed gene in NPC, which was subsequently confirmed to be upregulated in clinical NPC tissue samples. NPC cells were subjected to sphere-formation conditions in low-attachment plates, followed by sorting of CD133⁺ cells, which were selected as NPC stem cells after further characterization of stem cell biomarkers. ZIC2 was then shown to be enriched in NPC stem cells at both mRNA and protein levels. However, loss of ZIC2 was associated with the self-renewal, proliferative and tumorigenic properties of NPC stem cells. Next, miRNAs potentially able to target ZIC2 were predicted by the intersection of mirDIP and TargetScan database results, and miRNA miR-873 was found to be downregulated in NPC tissues in general but especially in NPC stem cells. Upregulation of miR-873 inhibited the stem-like properties and tumorigenicity of NPC stem cells, which was found to take place through downregulation of ZIC2 and disruption of the AKT signaling pathway. Collectively, the results obtained suggest that overexpression of miR-873 could aid NPC tumor suppression through reduction of the malignant potential of CSCs.

MicroRNA-301b and its target gene synaptosome-associated protein 91 as important modulators in esophageal cancer: functional experiments

The aim of this study was to probe the influence of microRNA-301b (miR-301b) in esophageal cancer pathogenesis. Based on the data acquired from The Cancer Genome Atlas database, we found that miR-301b was highly expressed in esophageal cancer tissues and high expression of miR-301b was related to worse prognosis in patients with esophageal cancer. Quantitative real-time PCR revealed that the expression of miR-301b was higher in all examined esophageal cancer cell lines (ECA109, KY-SE150, TE-1, and NEC) than that in a human esophageal epithelial cell line (HEEC). Upregulation/downregulation of miR-301b facilitated/suppressed the growth, migration, and invasion of ECA109/KY-SE150 cells. Synaptosome-associated protein 91 (SNAP91) was proved to be one of the target genes of miR-301b and was negatively modulated by miR-301b. Besides, SNAP91 was lowly expressed in human esophageal cancer tissues and cell lines. Meanwhile, low expression of SNAP91 was concerned with poor prognosis in patients with esophageal cancer. Furthermore, we discovered that overexpression/depletion of SNAP91 suppressed/facilitated the proliferation of KY-SE150/ECA109 cells. MiR-301b and SNAP91 had little impact on HEEC cell proliferation and this degree of influence was negligible compared with their impacts on esophageal cancer cell proliferation. By rescue assay, we showed that overexpression of SNAP91 restrained the growth, migration, and invasion of ECA109 cells with overexpressed miR-301b while knockdown of SNAP91 showed the contrary effects on KY-SE150 cells with downregulated miR-301b. These consequences indicated that miR-301b played an important effect on esophageal cancer cells through regulating SNAP91, insinuating that miR-301b/SNAP91 might be novel potential targets for esophageal cancer therapy and prognosis.

BHLHE41 suppresses MCF-7 cell invasion via MAPK/JNK pathway

Deregulation of the basic helix‐loop‐helix family member e41 (BHLHE41) has been characterized as a marker of progression of several cancers. In this study, we aimed to explore the mechanism by which BHLHE41 regulates the invasion of breast cancer cells. BHLHE41 suppresses, whereas the silencing of BHLHE41 promotes tumour invasion of both MCF‐7 and MDA‐MB‐231 cells. Meanwhile, BHLHE41 down‐regulated the transcription and translation of SNAI1, SNAI2, VIM and CDH2, and up‐regulated those of CLDN1, CLDN4 and CDH1. Reporter assay indicated that silencing of BHLHE41 dramatically activated the MAPK/JNK signalling pathway in MCF‐7 cell line and the hypoxia signalling pathway in MDA‐MB‐231 cell line. Furthermore, silencing of BHLHE41 activated the MAPK/JNK signalling pathway by up‐regulating phosphorylated JNK and failed to affect the expression of HIF‐1 alpha in MCF‐7 cells. After blocking the MAPK/JNK signalling pathway by specific inhibitor SP600125, silencing of BHLHE41 failed to promote tumour cell invasion. These results suggest that BHLHE41 facilitates MCF‐7 cell invasion mainly via the activation of MAPK/JNK signalling pathway. In conclusion, although BHLHE41 suppresses tumour invasion in MCF‐7 and MDA‐MB‐231 cell lines, the specific regulatory mechanisms may be different.

MicroRNA-873 serves a critical role in human cervical cancer proliferation and metastasis via regulating glioma-associated oncogene homolog 1

Cervical cancer is a common gynecological malignancy with high morbidity worldwide. MicroRNAs (miRNAs) serve critical roles in cervical cancer progression. Accumulating evidence indicates that miR-873 functions as a tumor suppressor in certain types of cancer. However, the function and mechanism of miR-873 in the progression of cervical cancer have not been completely elucidated. In the present study, the role and mechanism of miR-873 in the proliferation, migration and invasion of cervical cancer cells were investigated. miR-873 expression was markedly decreased in cervical cancer, while glioma-associated oncogene homolog 1 (GLI1) was found to be a direct target of miR-873 by conducting dual-luciferase reporter assays. Furthermore, miR-873 overexpression reduced the expression of GLI1, and decreased the proliferation, metastasis and epithelial-mesenchymal transition of cancer cells. In rescue experiments, overexpression of GLI1 in cervical cancer cells effectively reversed the inhibitory effect induced by miR-873 mimics. Therefore, the results of the present study suggested that miR-873 functions as a tumor suppressor miRNA, and future studies should address its potential application in the treatment of cervical cancer.

MicroRNA‑4712‑5p promotes proliferation of the vulvar squamous cell carcinoma cell line A431 by targeting PTEN through the AKT/cyclin D1 signaling pathways

The aim of the present study was to screen differentially expressed miRNAs in vulvar squamous cell carcinoma (VSCC), observe the role of microRNA-4712-5p in VSCC and investigate its targets and regulatory mechanism. Differentially expressed miRNAs in human VSCC tissues were screened. microRNA-4712-5p was selected and its expression level was verified in clinical tissue samples and the VSCC cell line A431 by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis. The overexpression vector of microRNA-4712-5p was prepared and transfected into A431 cells; subsequently, cell invasion and metastasis were examined by Cell Counting Kit-8 and Transwell migration assays. Furthermore, the target gene of miRNA-4712-5p was predicted by bioinformatics and verified by The Dual-Luciferase^® Reporter (DLR™) Assay System. The expression of phosphatase and tensin homologue (PTEN) and its downstream proteins, such as protein kinase B (PKB; AKT), glycogen synthase kinase (GSK)3β and cyclin D1, were detected by western blot assays. The expression level of microRNA-4712-5p in VSCC tissues and the A431 cell line was found to be significantly increased, promoting proliferation and invasion of VSCC. The DLR™ assay indicated that PTEN was a target of miR-4712-5p. RT-qPCR revealed that PTEN expression was markedly lower in VSCC tissues compared with that in adjacent tissues. After A431 cells were transfected with the miRNA-4712-5p overexpression vector, phospho-AKT (p-AKT) and cyclin D1 expression were notably increased, but miRNA-4712-5p-targeted PTEN and phospho-GSK3β (p-GSK3β) protein markedly decreased. Therefore, microRNA-4712-5p can reduce the expression of PTEN, further affecting its downstream p-AKT, p-GSK3β and cyclin D1 signaling pathways, promoting the proliferation and invasion of VSCC.

BHLHE41 promotes U87 and U251 cell proliferation via ERK/cyclinD1 signaling pathway

Purpose

The biological functions of BHLHE41 in the proliferation of glioblastoma remained unexplored. We aimed to investigate the biological roles and underlying molecular mechanisms of BHLHE41 in glioblastoma.

Materials and methods

We used multiple methods, including Western blot analysis, soft agar colony-formation assay, CCK8 assay, and flow cytometry, to evaluate the changes in multiple cellular functions after BHLHE41 knockdown or overexpression in U87 and U251 cell lines. The TCGA database was then used to analyze the associations between BHLHE41 expression with clinicopathological factors and the overall survival (OS) of glioma patients.

Results

This study determined that overexpression of BHLHE41 promoted glioma cell proliferation and colony formation. Besides, BHLHE41 upregulated cyclinD1, cyclinD3, and cyclinE1 expression and drove phase transition from G1 to S and G2 phases by upregulating these cyclins. In contrast, knockdown of BHLHE41 had an opposite effect on all of these parameters. However, BHLHE41 had no effect on apoptosis. Moreover, BHLHE41 activated MAPK/ERK signaling pathway to upregulate cyclinD1 expression. After the ERK signal pathway was blocked by a specific inhibitor, SCH772984, cyclinD1 upregulation was reversed. Furthermore, the median OS of low-grade glioma (LGG) patients with low to median level of BHLHE41 was 22.6 months, longer than that of the patients with high level of BHLHE41 (21.0 months).

Conclusion

BHLHE41 has an important role in the proliferation of glioblastoma and could serve as a novel candidate for targeted therapy of glioblastoma.

Mutual suppression between BHLHE40/BHLHE41 and the MIR301B-MIR130B cluster is involved in epithelial-to-mesenchymal transition of endometrial cancer cells

BHLHE40 and BHLHE41 (BHLHE40/41) are basic helix-loop-helix type transcription factors involved in multiple cell activities including epithelial-to-mesenchymal transition (EMT). However, the expression mechanism of BHLHE40/41 in EMT remains unclear. In the present study, we showed that the expression levels of BHLHE40/41 were negatively correlated with those of the microRNA (MIR) 130 family in endometrial cancer (EC) specimens. Our in vitro assays indicated that the expression of BHLHE40/41 was suppressed directly by the MIR130 family in a 3'-untranslated region-mediated manner. In EC cells, the MIR130 family promoted EMT and tumor cell invasion by suppressing the expression of BHLHE40/41. We identified the critical promoter region of the MIR301B-MIR130B cluster for its basal transcription by the transcription factor, SP1. We also found that BHLHE40/41 suppressed the expression of MIR301B and MIR130B, and we identified a binding site in the promoter region for BHLHE40/41. This study is the first to report that BHLHE40/41 and the MIR301B-MIR130B cluster suppressed each other to regulate EMT and invasion of EC cells. We propose that BHLHE40/41 and the MIR130 family are excellent markers to predict the progression of EC cases, and that molecular therapy targeting the MIR130 family-BHLHE40/41 axis may effectively control EC extension.

The effects of miR-429 on cell migration and invasion by targeting Slug in esophageal squamous cell carcinoma

Increasing evidence indicates that microRNAs may play important roles in tumor development and may take part in different processes in different cancers. miR-429 is known as a cancer suppressor or oncogene that is dysregulated in different malignancies, including esophageal squamous cell carcinoma (ESCC). However, the effect of miR-429 in ESCC has not been fully explored. The purpose of this study was to investigate the functions of miR-429 in ESCC. qRT-PCR assays were performed to detect miR-429 expression in ESCC tissues and cell lines. To assess the effects of miR-429 on ESCC cells, wound healing and transwell assays were used. Luciferase reporter and western blot assays were employed to determine whether Slug is a major target of miR-429.Our results showed that the expression levels of miR-429 in ESCC tissues and cells were lower than in normal esophageal epithelial tissues and cells. Furthermore, overexpression of endogenous miR-429 inhibited the migration and invasion of ESCC cell lines. In addition, Luciferase reporter and western blot assays provided evidence that miR-429 can bind to the 3' untranslated regions of Slug to regulate its expression and that of downstream epithelial-to-mesenchymal transition (EMT) markers. We found that Slug serves as a major target of miR-429. miR-429 plays a vital role in ESCC progression and represents a new therapeutic target for ESCC.

MicroRNA-873 inhibits the proliferation and invasion of endometrial cancer cells by directly targeting hepatoma-derived growth factor

An accumulation of evidence has demonstrated that abnormal microRNA (miRNA or miR) expression is associated with different types of cancer, including endometrial cancer (EC). The dysregulation of miRNAs may serve important roles in the development and progression of EC by regulating multiple aggressive biological behaviors, including cell proliferation, apoptosis, metastasis and angiogenesis. An in-depth understanding of the miRNAs associated with EC initiation and progression may be crucial for identifying successful therapeutic techniques. miR-873 has been demonstrated to be dysregulated in different types of cancer. However, the expression status and regulatory roles of miR-873 are yet to be elucidated in EC. In the present study, reverse transcription-quantitative PCR was carried out to detect miR-873 expression in EC tissues and cell lines. Cell Counting Kit-8 and in vitro invasion assays were utilized to determine the influence of miR-873 on the proliferation and invasion of EC cells. miR-873 expression was revealed to be downregulated in EC tissues and cell lines. Decreased miR-873 expression was significantly associated with International Federation of Gynecology and Obstetrics stage and lymph node metastasis of patients with EC. Functional assays revealed that resumed miR-873 expression suppressed the proliferation and invasion of EC cells. Additionally, hepatoma-derived growth factor (HDGF) was indicated to be a direct target gene of miR-873 in EC cells. HDGF was highly expressed in EC tissues and inversely correlated with miR-873 expression. HDGF silencing also imitated the tumor-suppressor activity of miR-873 overexpression in EC cells. A series of rescue experiments identified that recovered HDGF expression hindered the anti-proliferative and anti-invasive roles of miR-873 upregulation in EC cells. In conclusion, the present study indicated that miR-873 serves an important role as a tumor suppressor in EC development by directly targeting HDGF. The results may provide a novel insight into clinical treatments, which can be used to prevent EC aggression.

MiR-873/PD-L1 axis regulates the stemness of breast cancer cells

Background

Breast cancer stem cells have self-renewal capability and are resistant to conventional chemotherapy. PD-L1 could promote the expression of stemness markers (OCT4 and Nanog) in breast cancer stem cells. However, the mechanisms by which PD-L1 regulates the stemness of breast cancer cells and PD-L1 is regulated in breast cancer cells are still unclear.

Methods

Lentivirus infection was used to construct stable cell lines. The correlation between PD-L1 and stemness markers expression was evaluated in clinical samples. Additionally, luciferase reporter assay combined with RNA-Fluorescence in situ hybridization (RNA-FISH) and RNA-binding protein immunoprecipitation (RIP) assays were used to verify the direct binding of miR-873 on PD-L1. Furthermore, flow cytometry, mammosphere formation combined with nude mouse tumor xenograft model were carried out to examine the effects of miR-873/PD-L1 axis on the stemness of breast cancer cells. Finally, MTT assay was performed to determine the effects of miR-873/PD-L1 axis on drug resistance.

Findings

PD-L1 expression was positively correlated with the expression of stemness markers, and overexpression of PD-L1 contributed to chemoresistance and stemness-like properties in breast cancer cells via activating PI3K/Akt and ERK1/2 pathways. Mechanistically, miR-873 inhibited PD-L1 expression through directly binding to its 3′-untranslated region (UTR), and miR-873 attenuated the stemness and chemoresistance of breast cancer cells which was dependent on PD-L1 and the downstream PI3K/Akt and ERK1/2 signaling. Notably, the promotion of PD-L1 on the stemness and chemoresistance was enhanced by recombinant PD-1 (rPD-1), this effect was attenuated by PD-1/PD-L1 inhibitor.

Interpretation

miR-873/PD-L1 regulatory axis might serve as a therapeutic target to enhance the chemo-sensitivity and eliminate the stemness of breast cancer cells.

Fund

This work was supported by the National Nature Science Foundation of China, No. 81702957, China Postdoctoral Science Foundation, No. 2017M620230, the Postdoctoral Research Funding Scheme of Jiangsu Province (2017), No. 1701197B, and the Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions.

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A critical role of PD-L1 in stemness and chemoresistance is proposed.

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A negative miR-873/PD-L1 interaction was identified in breast cancer cells.

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The mechanisms of miR-873/PD-L1 in stemness and chemoresistance were studied.

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The results provide new insights for breast cancer progression and treatment.

Identification of a nine-miRNA signature for the prognosis of Uveal Melanoma

The present study aims to construct a miRNA-based predictive signature of Uveal melanoma (UM) based on the database of the cancer genome atlas (TCGA). We obtained miRNA expression profiles and clinical information of 80 UM patients from TCGA, and randomly divided them into a training and a testing set. After data processing and forward screening, a total of 204 miRNAs with prognostic value were then examined by the Cox proportional hazard regression model in the training set. Receiver operating curve (ROC) analysis was applied to validate the accuracy of the signature. The biological relevance of putative miRNA target genes was also analyzed using the bioinformatics method. As a result, a linear prognostic model consisting of 9 miRNAs (miR-195, miR-224, miR-365a, miR-365b, miR-452, miR-4709, miR-7702, miR-513c, miR-873) was developed to divide UM patients into a high- and a low-risk group. Patients assigned to the high-risk group had significantly shorter overall survival than those in the low-risk group, which was further confirmed by the Area under curve (AUC) value of 0.858 at 5 year obtained from ROC. Gene Ontology (GO) analysis indicated that predicted target genes of these miRNAs are primarily associated with the modulation of protein expression and function, such as the activity of ubiquitin protein ligase and protein kinase. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that these genes were involved in multiple signaling pathways linked to carcinogenesis. The tumor specific 9-miRNA signature was also verified in the testing and entire set. In summary, based on UM data of TCGA, we identified and validated a 9-miRNA-based prognostic signature.