MicroRNA‑665 suppresses the growth and migration of ovarian cancer cells by targeting HOXA10

Extracellular Vesicles-ceRNAs as Ovarian Cancer Biomarkers: Looking into circRNA-miRNA-mRNA Code

Simple Summary

Patients with ovarian cancer have a very poor chance of long-term survival, usually due to advanced disease at the time of diagnosis. Emerging evidence suggests that extracellular vesicles contain noncoding RNAs such as microRNAs, piwiRNAs, circular RNAs, and long noncoding RNAs, with regulatory effects on ovarian cancer. In this review, we focus on ovarian cancer-associated circular RNA shuttled by extracellular vesicles as mediators of cancer progression and novel biomarkers in liquid biopsy. We propose a circular-RNA–microRNA-mRNA code that can reveal the regulatory network created by extracellular vesicles, noncoding RNAs, and mRNAs in ovarian cancer. Future research in this field will help to identify novel diagnostic biomarkers and druggable therapeutic targets, which will ultimately benefit patients.

Abstract

Ovarian cancer (OC) is one of the most lethal gynecologic malignancies in females worldwide. OC is frequently diagnosed at an advanced stage due to a lack of specific symptoms and effective screening tests, resulting in a poor prognosis for patients. Age, genetic alterations, and family history are the major risk factors for OC pathogenesis. Understanding the molecular mechanisms underlying OC progression, identifying new biomarkers for early detection, and discovering potential targets for new drugs are urgent needs. Liquid biopsy (LB), used for cancer detection and management, consists of a minimally invasive approach and practical alternative source to investigate tumor alterations by testing extracellular vesicles (EVs), circulating tumor cells, tumor-educated platelets, and cell-free nucleic acids. EVs are nanosize vesicles shuttling proteins, lipids, and nucleic acids, such as DNA, RNA, and non-coding RNAs (ncRNAs), that can induce phenotypic reprogramming of target cells. EVs are natural intercellular shuttles for ncRNAs, such as microRNAs (miRNAs) and circular-RNAs (circRNAs), known to have regulatory effects in OC. Here we focus on the involvement of circRNAs and miRNAs in OC cancer progression. The circRNA-microRNA-mRNA axis has been investigated with Circbank and miRwalk analysis, unraveling the intricate and detailed regulatory network created by EVs, ncRNAs, and mRNAs in OC.

Analysis of Competitive Endogenous Mechanism and Survival Prognosis of Serum Exosomes in Ovarian Cancer Patients Based on Sequencing Technology and Bioinformatics

Background: We determined the competitive endogenous in serum exosomes of ovarian cancer patients via sequencing technology and raw signal analysis. We performed an in-depth study of the potential mechanisms of ovarian cancer, predicted potential therapeutic targets and performed survival analysis of the potential targets.

Methods: Serum exosomes from three ovarian cancer patients were used as the experimental group, serum exosomes from three patients with uterine fibroids were used as the control group, and whole transcriptome analysis of serum exosomes was performed to identify differentially expressed long noncoding RNAs (lncRNAs) and mRNAs in ovarian cancer. The miRcode database and miRNA target gene prediction website were used to predict the target genes. Cytoscape software was used to generate a competing endogenous RNA (ceRNA) network of competitive endogenous mechanism of serum exosomes in ovarian cancer, and the R language was used for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of the target genes. Finally, the TCGA website was used to download clinical and expression data related to ovarian cancer, and the common potential target genes obtained previously were analyzed for survival.

Results: A total of 117 differentially expressed lncRNAs as well as 513 differentially expressed mRNAs (p < 0.05, |log2 fold change (FC)|≥ 1.0) were obtained by combining sequencing data and raw signal analysis, and 841 predicted target genes were reciprocally mapped by combining the data from the miRcode database and miRNA target gene prediction website, resulting in 11 potential target genes related to ovarian cancer (FGFR3, BMPR1B, TRIM29, FBN2, PAPPA, CCDC58, IGSF3, FBXO10, GPAM, HOXA10, and LHFPL4). Survival analysis of the above 11 target genes revealed that the survival curve was statistically significant (p < 0.05) for HOXA10 but not for the other genes. Through enrichment analysis, we found that the above target genes were mainly involved in biological processes such as regulation of transmembrane receptor protein kinase activity, structural molecule activity with elasticity, transforming growth factor-activated receptor activity, and GABA receptor binding and were mainly enriched in signaling pathways regulating stem cell pluripotency, bladder cancer, glycerolipid metabolism, central carbon metabolism of cancer, and tyrosine stimulation to EGFR in signaling pathways such as resistance to enzyme inhibitors.

Conclusions: The serum exosomal DIO3OS-hsa-miR-27a-3p-HOXA10 competitive endogenous signaling axis affects ovarian cancer development and disease survival by targeting dysregulated transcriptional pathways in cancer.

ALKBH5-HOXA10 loop-mediated JAK2 m6A demethylation and cisplatin resistance in epithelial ovarian cancer

Background

Chemotherapy resistance remains a barrier to improving the prognosis of epithelial ovarian cancer (EOC). ALKBH5 has recently been shown to be one of the RNA N6-methyladenosine (m6A) demethyltransferases associated with various cancers, but its role in cancer therapeutic resistance remains unclear. This study aimed to investigate the role of AlkB homolog 5 (ALKBH5) in cisplatin-resistant EOC.

Methods

Functional assays were performed both in vitro and in vivo. RNA sequencing (RNA-seq), m6A-modified RNA immunoprecipitation sequencing (MeRIP-seq), chromatin immunoprecipitation, RNA immunoprecipitation, and luciferase reporter and actinomycin-D assays were performed to investigate RNA/RNA interaction and m6A modification of the ALKBH5-HOXA10 loop.

Results

ALKBH5 was upregulated in cisplatin-resistant EOC and promoted cancer cell cisplatin resistance both in vivo and in vitro. Notably, HOXA10 formed a loop with ALKBH5 and was found to be the upstream transcription factor of ALKBH5. HOXA10 overexpression also facilitated EOC cell chemoresistance both in vivo and in vitro. Collective results of MeRIP-seq and RNA-seq showed that JAK2 is the m6A-modified gene targeted by ALKBH5. The JAK2/STAT3 signaling pathway was activated by overexpression of the ALKBH5-HOXA10 loop, resulting in EOC chemoresistance. Cell sensitivity to cisplatin was rescued by ALKBH5 and HOXA10 knockdown or inhibition of the JAK2/STAT3 signaling pathway in EOC cells overexpressing ALKBH5-HOXA10.

Conclusions

The ALKBH5-HOXA10 loop jointly activates the JAK2/STAT3 signaling pathway by mediating JAK2 m6A demethylation, promoting EOC resistance to cisplatin. Thus, inhibition of the expression of the ALKBH5-HOXA10 loop may be a potential strategy to overcome cisplatin resistance in EOC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02088-1.

miR-486 Promotes the Invasion and Cell Cycle Progression of Ovarian Cancer Cells by Targeting CADM1

Objective

To explore the role and possible underlying mechanism of miR-486 in ovarian cancer (OC) cells.

Methods

The expression of miR-486 and CADM1 was detected by qRT-PCR in OC tissues and adjacent nontumor tissues and OC cell lines. The dual-luciferase reporter gene system was used to determine the targeting relationship between miR-486 and CADM1. CCK-8, colony formation assay, Transwell, and flow cytometry were performed to detect cell proliferation, cell invasion, cell cycle progression, and the apoptotic cell death, respectively. Western blot was carried out to detect the expression of CADM1 protein and the proteins associated with cell cycle progression.

Results

miR-486 was significantly upregulated in OC tissues and cells, while CADM1 expression was significantly downregulated. Dual-luciferase reporter assays further confirmed that CADM1 was a target gene of miR-486. Interference with miR-486 could inhibit the proliferation and invasion and promoted the apoptosis of SKOV3 cells. Knocking down both miR-486 and CADM1 significantly increased the SKOV3 cell proliferation, invasion, and the number of cells transitioning from the G0/G1 phase into the S phase of cell cycle and reduced the cellular apoptosis. Western blot analysis revealed that the expression of cell cycle progression-related proteins (CyclinD1, CyclinE, and CDK6) was significantly reduced, and the p21 expression was increased when interfering with both miR-486 and CADM1 expression.

Conclusion

Our results suggested that miR-486 could act as a tumor promoter by targeting CADM1 and be a potential therapeutic target for the treatment of OC.

MicroRNA-665 regulates the proliferation, apoptosis and adhesion of gastric cancer cells by binding to cadherin 3

Numerous studies have reported that abnormal cadherin 3 (CDH3) and microRNA (miRNA/miR)-665 expression can induce the progression of gastric cancer (GC). However, the mechanism of interaction between miR-665 and CDH3 in GC requires further investigation. The present study aimed to investigate the influence of miR-665 and CDH3 in GC development. The effect of miR-665 and CDH3 on GC tissues and cell lines was examined using reverse transcription-quantitative PCR. Subsequently, CDH3 protein expression in GC cell lines was detected using western blotting. To confirm the association between miR-665 and CDH3, a dual-luciferase reporter assay system was employed. Cell proliferation and adhesion were analyzed using BrdU ELISA, MTT and cell adhesion assays. Finally, caspase-3 activity assay kit and FITC apoptosis detection kit were used for the determination of apoptosis of GC cells. The current findings confirmed the upregulation of CDH3 expression in GC cell lines and tissues. Experimental results indicated that CDH3 overexpression increased cell proliferation and adhesion, but decreased the apoptosis level of the cells. Similarly, the miR-665 inhibitor enhanced cell proliferation and adhesion, but inhibited apoptosis of GC cells. Additionally, it was observed that CDH3 was a direct target of miR-665 in GC cells and that miR-665 inhibited CDH3 expression, thereby repressing the progression of GC. In conclusion, the present study suggested that by targeting CDH3, miR-665 suppressed the progression of GC. These findings may provide a significant theoretical basis for future GC clinical therapy.

miR-665 is downregulated in glioma and inhibits tumor cell proliferation, migration and invasion by targeting high mobility group box 1

Glioma is the most common brain tumor in adults. microRNAs (miRNAs/miRs) play an essential role in tumor development and progression. The present study aimed to investigate the potential clinical significance and function of miR-665 in glioma. Reverse transcription-quantitative PCR analysis was used to detect the expression of miR-665 in glioma tissues and cells. Survival curves were constructed using the Kaplan-Meier method. Cox regression analysis was performed to investigate the prognostic significance of miR-665. Cell Counting Kit-8 and Transwell assays were used to evaluate the role of miR-665 in glioma. Bioinformatics analysis and Dual-luciferase reporter assays were used to predict the putative direct targets of miR-665. Western blotting was used to evaluate the activity of the Wnt/β-catenin pathway. The relative expression of miR-665 was decreased in glioma tissues and cells and this downregulation was significantly associated with the Karnofsky performance scale score and World Health Organisation grade. Patients with glioma with low miR-665 expression had a shorter overall survival time compared with the high expression group. Besides, overexpression of miR-665 suppressed the proliferation, migration and invasion of glioma cells, while knockdown of miR-665 promoted these cellular behaviors. High mobility group box (HMGB)1 was a direct target of miR-665. It was also demonstrated that miR-665 may suppress glioma progression by targeting HMGB1 and inhibiting the Wnt/β-catenin pathway. Taken together, these data suggested that miR-665 may have a tumor suppressor role in glioma by targeting HMGB1. Therefore, miR-665 may be a novel prognostic biomarker and the miR-665/HMGB1 axis may be a novel therapeutic target for the treatment of glioma.

The Role of microRNAs in Epithelial Ovarian Cancer Metastasis

Epithelial ovarian cancer (EOC) is the deadliest gynecological cancer, and the major cause of death is mainly attributed to metastasis. MicroRNAs (miRNAs) are a group of small non-coding RNAs that exert important regulatory functions in many biological processes through their effects on regulating gene expression. In most cases, miRNAs interact with the 3′ UTRs of target mRNAs to induce their degradation and suppress their translation. Aberrant expression of miRNAs has been detected in EOC tumors and/or the biological fluids of EOC patients. Such dysregulation occurs as the result of alterations in DNA copy numbers, epigenetic regulation, and miRNA biogenesis. Many studies have demonstrated that miRNAs can promote or suppress events related to EOC metastasis, such as cell migration, invasion, epithelial-to-mesenchymal transition, and interaction with the tumor microenvironment. In this review, we provide a brief overview of miRNA biogenesis and highlight some key events and regulations related to EOC metastasis. We summarize current knowledge on how miRNAs are dysregulated, focusing on those that have been reported to regulate metastasis. Furthermore, we discuss the role of miRNAs in promoting and inhibiting EOC metastasis. Finally, we point out some limitations of current findings and suggest future research directions in the field.

LINC01089 Blocks the Proliferation and Metastasis of Colorectal Cancer Cells via Regulating miR-27b-3p/HOXA10 Axis

Background

An increasing number of studies demonstrate that long non-coding RNAs (lncRNAs) are regulators in cancer biology. Nevertheless, the expression and mechanism of LINC01089 in colorectal cancer (CRC) remain unclear.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was taken to investigate the expression levels of LINC01089 and miR-27b-3p in CRC tissues and cells. MTT method and transwell test were employed to assess the proliferation and invasion of CRC cells, respectively. Dual-luciferase activity reporter assay, RNA immunoprecipitation assay, Pearson's correlation analysis, and Western blot were performed to investigate the regulatory mechanism of LINC01089/miR-27b-3p/HOXA10 axis in CRC.

Results

LINC01089 was down-regulated in CRC tissues and cell lines. LINC01089 overexpression impeded the proliferation and invasion of SW620 and LoVo cells, whereas LINC01089 knockdown increased the malignancy of SW480 and HT29 cells. Moreover, LINC01089 directly interacted with miR-27b-3p to repressed its expression and indirectly promoted the expression of HOXA10.

Conclusion

LINC01089 impedes the proliferation and invasion of colorectal cancer cells by adsorbing miR-27b-3p and up-regulating the expression of HOXA10.

RHPN1-AS1 promotes cell proliferation and migration via miR-665/Akt3 in ovarian cancer

Recent efforts have revealed that long non-coding RNAs exert crucial roles in cancer initiation and progression. RHPN1-AS1 is a 2030 bp transcript from human chromosome 8q24, and involved in tumorigenesis in uveal melanoma and non-small cell lung cancer, but it remains unknown in ovarian cancer. This study focused on the role of RHPN1-AS1 in ovarian cancer and found that RHPN1-AS1 was up-regulated in ovarian cancer tissues and cell lines. Overexpression of RHPN1-AS1 promoted ovarian cancer cell proliferation, migration, and invasion. Mechanistically, overexpression of RHPN1-AS1 decreased the expression of miR-665 and subsequently promoted the expression of Akt3 at posttranscriptional level. Taken together, RHPN1-AS1 positively regulated the expression of Akt3 through sponging miR-665, and exerted an oncogenic role in ovarian cancer progression, and indicates that RHPN1-AS1 may be a potential therapeutic target in ovarian cancer.

miR-665 Suppresses the Epithelial-Mesenchymal Transition and Progression of Gastric Cancer by Targeting CRIM1

Background

Gastric cancer (GC) is one of the most common aggressive cancers and is characterized by high mortality. Increasing evidence has shown that microRNA-665 (miRNA-665) serves as inhibiting-miRNA in cancers. However, the role of miR-665 in GC is yet unclear.

Methods

miR-665 was first analyzed using bioinformatics. Subsequent quantitative real-time PCR was used to detect miR-665 expression levels in different GC cell lines and tissues. The function of miR-665 in GC cells was determined via Cell Counting Kit 8, colony formation, wound healing, and transwell assays. Furthermore, Western blotting was utilized to measure the expression level of epithelial–mesenchymal transition (EMT)-related proteins. The target prediction and luciferase reporter assays were performed to confirm the binding between miR-665 and 3ʹ-UTR of the CRIM1 gene. In addition, rescue assays were used to determine whether CRIM1 upregulation abolished the inhibitory effect of miR-665.

Results

The expression of miR-665 was significantly decreased in GC patients and GC cell lines. Clinical and pathological analyses showed that the low expression of miR-665 was significantly associated with high TNM stage (P = 0.007), distant metastasis (P = 0.031), and poor differentiation (P = 0.029). Endogenic mimics of miR-665 remarkably suppressed GC cell proliferation, migration, invasion, and EMT in in vitro experiments. Inhibition of miR-665 expression induced the opposite effects. The results of the bioinformatics analysis and dual-luciferase assay showed that miR-665 targeted the 3ʹ-UTR of the CRIM1 gene. Rescue assays revealed that overexpression of CRIM1 attenuated the inhibitory effects of miR-665 in GC progression and EMT.

Conclusion

The overall study results demonstrated that miR-665 inhibits tumor progression and EMT in GC by targeting CRIM1, indicating that miR-665 might be a potential therapeutic target in the treatment of GC patients.

Upregulated miR-665 expression independently predicts poor prognosis of lung cancer and facilitates tumor cell proliferation, migration and invasion

Non-small cell lung cancer (NSCLC) is one of the leading causes of global cancer-associated mortality. Aberrant microRNAs (miRs) have been reported to be involved in the pathogenesis of various cancer types. The present study aimed to investigate the expression profile and prognostic value of miR-665 in patients with NSCLC, and to analyze its functional role in tumor progression using NSCLC cells. Reverse transcription-quantitative PCR was used to estimate the expression levels of miR-665. Kaplan-Meier survival curves and Cox regression analysis were performed to evaluate the prognostic value of miR-665. The effects of miR-665 on NSCLC cell proliferation, migration and invasion were examined by cell transfection, and the target gene of miR-665 was explored. miR-665 expression was elevated in the tissue and cell samples of NSCLC. This increased miR-665 expression was associated with lymph node metastasis and TNM stage. An independent association between miR-665 and overall survival was identified in patients with NSCLC. When regulating the expression levels of miR-665 in vitro, NSCLC cell proliferation, migration and invasion were enhanced by overexpression of miR-665, but were inhibited by knockdown of miR-665. The luciferase activity results indicated that the protein tyrosine phosphatase receptor type B (PTPRB) was a direct target of miR-665 in NSCLC cells. The present study provided evidence for the clinical significance of a decreased expression of miR-665 in the prognosis of NSCLC. Upregulation of miR-665 contributed to tumor cell proliferation, migration and invasion by targeting PTPRB, suggesting the potential of miR-665 as a candidate therapeutic target for NSCLC treatment.

CircCTDP1 promotes nasopharyngeal carcinoma progression via a microRNA‑320b/HOXA10/TGFβ2 pathway

Circular RNAs have been reported to play a vital role in the development and progression of various types of cancer. However, the underlying molecular role of circular RNA CTDP1 (circCTDP1) in the tumorigenesis of nasopharyngeal carcinoma (NPC) remains unknown. In the present study, circCTDP1 expression was found to be markedly upregulated in NPC tissues and cell lines (SUNE1, SUNE2 and 6-10B cell lines). Knockdown of circCTDP1 resulted in inhibition of proliferation, migration and invasion, and promoted apoptosis of NPC cells. Moreover, circCTDP1 directly interacted with microRNA (miR)-320b based on bioinformatics prediction and dual luciferase assay, and transfection with an miR-320b inhibitor reversed the effects of circCTDP1 knockdown on NPC cells. Furthermore, circCTDP1/miR-320b promoted NPC progression by regulating the expression of homeobox A10 (HOXA10). In addition, it was demonstrated that HOXA10 may exert its oncogenic role in NPC by regulating the expression of transforming growth factor β2 (TGFβ2). Taken together, these results revealed a novel regulatory mechanism, which may provide an improved understanding of NPC tumorigenesis and be useful in the development of potential targets for NPC therapy.

CircRNA_100876 Is Upregulated in Gastric Cancer (GC) and Promotes the GC Cells' Growth, Migration and Invasion via miR-665/YAP1 Signaling

The present study aimed to investigate the biological function and relative mechanisms of circRNA_100876 in gastric cancer (GC). To this end, quantitative real-time polymerase chain reaction (RT-qPCR) was performed to examine the expression of circRNA_100876 and miR-665 in GC tissues and cells, and circRNA_100876 expression was depleted by the transfection of circ_100876-targeting siRNAs. CCK-8, flow cytometry, and Transwell assays were applied to examine GC cell cycle distribution, proliferation, apoptosis, migration, and invasion abilities. Proteins related to apoptosis and epithelial-mesenchymal transition (EMT) were detected by western blotting. Luciferase reporter assays were conducted to verify the direct target site between circRNA_100876 and miR-665. Our study confirmed that circRNA_100876 was highly expressed in GC lesions compared with the adjacent normal tissues (P < 0.001). High circRNA_100876 expression was negatively associated with survival outcome (P = 0.000). Furthermore, the down-regulation of circRNA_100876 could inhibit GC cell proliferation, invasion, and migration by suppressing the EMT pathway. Further study suggested that circRNA_100876 could act as a competing endogenous RNA by sequestering miR-665, and luciferase activity assay indicated that circRNA_100876 could bind directly with miR-665. Moreover, we found that Yes-associated protein 1 (YAP1) was the downstream target gene of miR-665, miR-665 knockdown could up-regulate YAP1 expression in MKN45 cells, and YAP1 knockdown could inhibit MKN45 cell proliferation, migration and invasion. Therefore, we demonstrated that circRNA_100876 over-expression in GC could promote GC tumor growth, migration and invasion and exert its effects through miR-665/YAP1 signaling.

miRNA Regulation of Glutathione Homeostasis in Cancer Initiation, Progression and Therapy Resistance

Glutathione (GSH) is the most abundant antioxidant that contributes to regulating the cellular production of Reactive Oxygen Species (ROS) which, maintained at physiological levels, can exert a function of second messengers in living organisms. In fact, it has been demonstrated that moderate amounts of ROS can activate the signaling pathways involved in cell growth and proliferation, while high levels of ROS induce DNA damage leading to cancer development. Therefore, GSH is a crucial player in the maintenance of redox homeostasis and its metabolism has a role in tumor initiation, progression, and therapy resistance. Our recent studies demonstrated that neuroblastoma cells resistant to etoposide, a common chemotherapeutic drug, show a partial monoallelic deletion of the locus coding for miRNA 15a and 16-1 leading to a loss of these miRNAs and the activation of GSH-dependent responses. Therefore, the aim of this review is to highlight the role of specific miRNAs in the modulation of intracellular GSH levels in order to take into consideration the use of modulators of miRNA expression as a useful strategy to better sensitize tumors to current therapies.

LINC00565 promotes proliferation and inhibits apoptosis of gastric cancer by targeting miR-665/AKT3 axis

Background

Numerous studies have shown that long noncoding RNA (lncRNA) is involved in gastric cancer (GC). A relevant microarray containing gastric cancer-related lncRNAs was downloaded from The Cancer Genome Atlas database.

Methods

qRT-PCR was used to analyze LINC00565 and AKT3 expression in tumor tissues and cell lines. Proliferative, colony formation and apoptotic abilities of GC cells after transfection of sh-LINC00565 were determined by CCK-8, colony formation assay and flow cytometry, respectively. RIP was enrolled to detect the interaction between LINC00565, AKT3 and miR-665. Dual luciferase assay was used to confirm the relation between miR-665 and LINC00565 and AKT3.

Results

Expression level of LINC00565 in GC tissue was highly expressed in GC, which was negatively correlated to prognosis of GC patients. The results showed that knockdown of LINC00565 decreased proliferative and colony formation abilities, and induced apoptosis of GC cells. Pearson analysis showed that LINC00565 was positively correlated with AKT3. Besides, AKT3 was significantly up-regulated in GC. In addition, knockdown of LINC00565 down-regulated AKT3. In order to explore the mechanism, we found that miR-665 could bind to LINC00565 by bioinformatics. Dual-luciferase reporter gene assay and RIP assay both verified the binding relationship between miR-665 and AKT3. Finally, rescue experiments were carried out to explore whether AKT3 could reverse the anti-cancer effect of low-level LINC00565 on GC development.

Conclusion

In summary, the expression of LINC00565 is upregulated in GC. LINC00565 can be used as the sponge of miR-665 to up-regulate the expression of AKT3, thus promoting the progression of GC.

EXT1, Regulated by MiR-665, Promotes Cell Apoptosis via ERK1/2 Signaling Pathway in Acute Lymphoblastic Leukemia

Background

EXT1 is an endoplasmic reticulum-resident glycosyl transferase whose intracellular expression alters the biosynthesis and distribution of heparan sulfate. EXT1 is regarded as a classic tumor suppressor. MiR-665 can act as either an oncogene or tumor-suppressing gene in different tumors. The aim of the current study was to determine the function and molecular mechanisms of EXT1 and miR-665 in acute lymphoblastic leukemia (ALL).

Material/Methods

EXT1 expression in ALL was evaluated by real-time polymerase chain reaction (RT-PCR) and western blotting. The effects of EXT1 in ALL were explored by Cell Counting Kit-8 (CCK-8)/EdU assays, western blotting, flow cytometry, and in vivo tumorigenesis assays. Label-free quantification was used to detect differentially expressed proteins in EXT1-overexpressing Reh cells.

Results

EXT1 expression is downregulated in ALL and negatively correlated with miR-665 expression. Moreover, low EXT1 and high miR-665 expression levels in adult ALL bone marrow tissues are correlated with poor patient survival. Our study showed that EXT1 modulates the proliferation and apoptosis of ALL cells in vitro and in vivo and that miR-665 promotes cell growth and inhibits apoptosis by suppressing EXT1. EXT1 promotes cell apoptosis via deactivating the ERK1/2 pathway.

Conclusions

In conclusion, this study is the first to confirm the association between low EXT1 levels and several clinical features of ALL. Low bone marrow EXT1 levels independently predict poor prognoses in adult ALL patients. Thus, our study suggests that EXT1- or miR-665-targeted strategies can confer the therapeutic effect of promoting apoptosis by deactivating the ERK1/2 pathway.

HOX Genes in High Grade Ovarian Cancer

HOX genes are highly conserved members of the homeobox superfamily that have a crucial role in determining cellular identity. High grade ovarian cancer is the most lethal gynaecological malignancy. Our understanding of the role of HOX genes in the oncogenesis of ovarian cancer is evolving, and here we review their dysregulated expression patterns, their function in cell survival and invasion, their potential uses as biomarkers, and ways in which HOX genes are being targeted with new and existing drugs.

MicroRNA-377-3p inhibits growth and invasion through sponging JAG1 in ovarian cancer

BACKGROUND

Ovarian cancer is the one of the most deadly gynecologic malignancy among cancer related death in women. However, the treatment for ovarian cancer is still limited. In this study, we aimed to explore the inhibition potential of miR-377-3p in ovarian cancer and explore the mechanism of this effect.

METHODS

Quantitative real-time PCR was used to detect the mRNA or microRNA (miRNA) levels. CCK-8, wound-healing, transwell assay were used to detect cell proliferation, migration and invasion. The protein levels were examined by western blot. The dual luciferase reporter assay was conducted to examine the luciferase activity. Tumor volume was measured and Ki67 was detected via immunohistochemistry.

RESULTS

qRT-PCR results showed that miR-377-3p was downregulated in ovarian cancer patients. MiR-377-3p mimics suppressed cell proliferation, migration, invasion and decreased the JAG1 level. However, miR-377-3p inhibitor promoted these appearances. Interestingly, we found JAG1 was a target gene of miR-377-3p. JAG1 overexpression reversed the miR-377-3p-induced inhibition of proliferation and invasion. In addition, miR-377-3p inhibited ovarian cancer tumorigenesis in vivo, indicating by decreased tumor volume and staining of Ki67.

CONCLUSION

The results showed that miR-377-3p inhibited growth and invasion of ovarian cancer cells by targeting JAG1.

HOXA10 deteriorates gastric cancer through activating JAK1/STAT3 signaling pathway

Background: HOXA10 has been reported to be deregulated in many kinds of cancers including gastric cancer. But its role in gastric cancer progression is controversial. Therefore, the current study was performed to explore the role and mechanism of HOXA10 in gastric cancer.

Materials and methods: IHC and Western blotting assays were used to assess HOXA10 expression in gastric cancer tissues and cells. Lentivirus infection was used to alter HOXA10, STAT3 and JAK1 expression in gastric cancer NCI-N87 and MKN28 cells. MTT, cloning formation, flow cytometry and in vivo xenotransplantation experiments were carried out to assess cell proliferation, cloning formation, apoptosis and tumorigenesis.

Results: HOXA10 expression was obviously increased in gastric cancer tissues and cells when compared with the normal gastric tissue samples and cells. Upregulation of HOXA10 significantly enhanced cell proliferation, cloning formation and tumorigenesis abilities and reduced cell apoptosis in gastric cancer, and promoted the activation of JAK1/STAT3 signaling. In addition, we showed that the effects of HOXA10 on the promotion of cell viability and tumorigenesis and cell apoptosis repression were all weakened when JAK1 or STAT3 was downregulated.

Conclusion: This study demonstrates that HOXA10 functions as an oncogene in gastric cancer through activating JAK1/STAT3 signaling.

miR-665 expression predicts poor survival and promotes tumor metastasis by targeting NR4A3 in breast cancer

Cancer metastasis is the main cause of death in breast cancer (BC) patients. Therefore, prediction and treatment of metastasis is critical for enhancing the survival of BC patients. In this study, we aimed to identify biomarkers that can predict metastasis of BC and elucidate the underlying mechanism of the functional involvement of such markers in metastasis. miRNA expression profile was analyzed using a custom microarray system in 422 BC tissues. The relationship between the upregulated miR-665, metastasis and survival of BC was analyzed and verified in another set of 161 BC samples. The biological function of miR-665 in BC carcinogenesis was explored with in vitro and in vivo methods. The target gene of miR-665 and its signaling cascade were also analyzed. There are 399 differentially expressed miRNAs between BC and noncancerous tissues, of which miR-665 is the most upregulated miRNA in the BC tissues compared with non-tumor breast tissues (P < 0.001). The expression of miR-665 predicts metastasis and poor survival in 422 BC patients, which is verified in another 161 BC patients and 2323 BC cases from online databases. Ectopic miR-665 expression promotes epithelial–mesenchymal transition (EMT), proliferation, migration and invasion of BC cells, and increases tumor growth and metastasis of BC in mice. Bioinformatics, luciferase assay and other methods showed that nuclear receptor subfamily 4 group A member 3 (NR4A3) is a target of miR-665 in BC. Mechanistically, we demonstrated that miR-665 promotes EMT, invasion and metastasis of BC via inhibiting NR4A3 to activate MAPK/ERK kinase (MEK) signaling pathway. Our study demonstrates that miR-665 upregulation is associated with metastasis and poor survival in BC patients, and mechanistically, miR-665 enhances progression of BC via NR4A3/MEK signaling pathway. This study provides a new potential prognostic biomarker and therapeutic target for BC patients.

MicroRNA-665 inhibits the oncogenicity of retinoblastoma by directly targeting high-mobility group box 1 and inactivating the Wnt/β-catenin pathway

Purpose: Previous studies have revealed that microRNA-665 (miR-665) is dysregulated in a variety of human cancers. However, little is known regarding its expression profiles and functions in retinoblastoma (RB). Therefore, the aims of our study were to evaluate miR-665 expression in RB and determine the precise roles of miR-665 in the progression of RB.

Patients and methods: Herein, RT-qPCR was used to determine miR-665 expression levels in RB tissues and cell lines, and a series of functional experiments were performed to explore the influence of miR-665 on RB cell proliferation, colony formation, apoptosis, migration, and invasion as well as tumor growth. The molecular mechanisms underlying the tumor-suppressive action of miR-665 in RB were also explored.

Results: We found that miR-665 was markedly reduced in RB tissues and cell lines and that lower miR-665 expression was strongly associated with tumor size, TNM stage, and differentiation in patients with RB. Exogenous expression of miR-665 suppressed cell proliferation, colony formation, migration, and invasion, and induced cell apoptosis in RB cells, while silencing miR-665 expression had the opposite effects. In addition, upregulation of miR-665 decreased the tumor growth of RB cells in vivo. High-mobility group box 1 (HMGB1) was identified as a direct target of miR-665 in RB cells, and decreasing the expression of HMGB1 simulated the regulatory effects of miR-665 overexpression in RB cells, while knockdown of HMGB1 expression counteracted the miR-665-mediated antitumor effects in RB cells. Moreover, miR-665 was shown to regulate the Wnt/β-catenin signaling pathway by targeting HMGB1 in vitro and in vivo.

Conclusion: Taken together, our in vitro and in vivo results suggest that miR-665 acts as a tumor-suppressive miRNA in RB by directly targeting HMGB1 and inactivating the Wnt/β-catenin pathway. Hence, this miRNA is a candidate prognostic biomarker and therapeutic target in patients with RB.

DANCR-mediated microRNA-665 regulates proliferation and metastasis of cervical cancer through the ERK/SMAD pathway

Emerging evidence has indicated that microRNAs (miRNAs) play an important role in cervical cancer (CC). However, the role of miRNA (miR)-665 in cervical cancer remains unclear. The aim of the present study was to investigate the potential functions of miR-665 in CC and to identify the underlying mechanisms of action. Herein, we show that miR-665 was downregulated in CC tissues and cell lines, which is negatively correlated with tumor size, distant metastasis, advanced TNM stage and poor prognosis. Functionally, miR-665 inhibited cell proliferation, migration and invasion and resistance of cisplatin for CC cells, as well as tumor growth. We validated that transforming growth factor beta receptor 1 (TGFBR1) was a direct target of miR-665 and mediated the ERK/SMAD pathway. In addition, we identified miR-665 as the competing endogenous RNA for long noncoding (lnc)-DANCR. These observations suggested that lnc-DANCR-mediated miR-665 downregulation regulates the malignant phenotype of CC cells by targeting TGFBR1 through the ERK/SMAD pathway, which may present a pathway for novel therapeutic stratagems for CC therapy.