MicroRNA-1301 suppresses tumor cell migration and invasion by targeting the p53/UBE4B pathway in multiple human cancer cells

How MicroRNAs Command the Battle against Cancer

MicroRNAs (miRNAs) are small RNA molecules that regulate more than 30% of genes in humans. Recent studies have revealed that miRNAs play a crucial role in tumorigenesis. Large sets of miRNAs in human tumors are under-expressed compared to normal tissues. Furthermore, experiments have shown that interference with miRNA processing enhances tumorigenesis. Multiple studies have documented the causal role of miRNAs in cancer, and miRNA-based anticancer therapies are currently being developed. This review primarily focuses on two key points: (1) miRNAs and their role in human cancer and (2) the regulation of tumor suppressors by miRNAs. The review discusses (a) the regulation of the tumor suppressor p53 by miRNA, (b) the critical role of the miR-144/451 cluster in regulating the Itch-p63-Ago2 pathway, and (c) the regulation of PTEN by miRNAs. Future research and the perspectives of miRNA in cancer are also discussed. Understanding these pathways will open avenues for therapeutic interventions targeting miRNA regulation.

hsa-miR-1301-3p Promotes the Proliferation and Migration of Nonsmall Cell Lung Cancer Cells and Reduces Radiosensitivity via Targeting Homeodomain-Only Protein Homeobox

Background: There is increasing evidence that abnormal expression of microRNAs is involved in the occurrence and progression of tumors. In previous experiments, we found that the content of hsa-miR-1301-3p in tumor tissues of patients with nonsmall cell lung cancer (NSCLC) showed an obvious upward trend compared with that in normal tissues. We performed a detailed study on the impact and underlying mechanism of hsa-miR-1301-3p in NSCLC cells. Methods: The impact of hsa-miR-1301-3p on NSCLC cell proliferation, apoptosis, migration, and invasion was examined using colony formation, flow cytometry, modified Boyden chamber, and wound healing assays. Different doses of radiation were applied to NSCLC cells to investigate their sensitivity to radiotherapy. The potential target gene of hsa-miR-1301-3p was determined by dual-luciferase reporter assay and immunoblotting. Result: hsa-miR-1301-3p was upregulated in NSCLC tissues and cells. hsa-miR-1301-3p effectively promoted the rapid proliferation, migration, and invasion of NSCLC cells, while inhibiting apoptosis. It also induced radioresistance in NSCLC cells. hsa-miR-1301-3p targeted the homeodomain-only protein homeobox (HOPX) mRNA 3' untranslated region and inhibited its transcription in NSCLC cells. Exogenous HOPX overexpression antagonized the mechanism by which hsa-miR-1301-3p regulates NSCLC cell proliferation, metastasis, and apoptosis. Conclusions: hsa-miR-1301-3p plays an oncogenic role in the occurrence and development of NSCLC. By targeting HOPX, hsa-miR-1301-3p can not only promote the proliferation and metastasis of NSCLC cells, but also alleviate apoptosis and reduce radiosensitivity.

Upregulated UBE4B expression correlates with poor prognosis and tumor immune infiltration in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a major human health concern. Increasing evidence has demonstrated that ubiquitin ligase E4B (UBE4B) may be involved in the occurrence and development of various human cancers and may affect prognosis. However, the specific role and mechanism of UBE4B in HCC is unclear.

METHODS

A pan-cancer analysis of UBE4B expression, clinicopathological features, and prognosis was performed using bioinformatics techniques. Subsequently, the expression, prognosis, and correlation of UBE4B and its upstream miRNAs and lncRNAs were analyzed. We investigated the relationship between UBE4B expression and immune cell infiltration, immunomodulatory factors, and chemokines in HCC. The expression levels of UBE4B and its upstream lncRNAs (FGD5-AS1, LINC00858, and SNHG16) and miRNAs (hsa-miR-22-3p) were evaluated in HCC cell lines using qRT-PCR.

RESULTS

UBE4B expression increased in HCC and was correlated with a poor survival rate in patients with HCC. A ceRNA network was established to identify the UBE4B-hsa-miR-22-3p-FGD5-AS1/LINC00858/SNHG16 regulatory axis in HCC. UBE4B expression was significantly associated with immune cell infiltration, immunomodulators, chemokines, and their receptors in HCC. The mRNA expression of FGD5-AS1, LINC00858, SNHG16, and UBE4B was higher in the HCC cell lines (7721 and HepG2) than in the normal hepatocyte line (LO2), and the expression of hsa-miR-22-3p mRNA showed a decreasing trend.

CONCLUSIONS

Our findings showed that upregulation of UBE4B was associated with poor prognosis and tumor immune infiltration in HCC. These findings will aid in understanding the relevant functions of UBE4B and provide new strategies for drug development and exploration of prognosis-related biomarkers.

Identification of m7G Methylation-Related miRNA Signature Associated with Survival and Immune Microenvironment Regulation in Uterine Corpus Endometrial Carcinoma

Background. N7-methylguanosine (m7G) has been implicated in the development of cancer. The role of m7G-related miRNAs in the survival prediction of UCEC patients has not been investigated. Current research was the first to construct an m7G-related miRNA model to accurately predict the survival of patients with uterine corpus endometrial carcinoma (UCEC) and to explore immune cell infiltration and immune activity in the tumor microenvironment. Methods. RNA-seq data and clinical information of UCEC patients were derived from The Cancer Genome Atlas (TCGA) database. Using the TargetScan online database, we predicted miRNAs linked to the m7G-related genes and identified miRNAs which were significantly associated with the survival in UCEC patients and constructed a risk scoring model. The TCGA-UCEC cases were scored according to the risk model, and the high- and low-risk groups were divided by the median risk value. Gene enrichment analysis and immune cell infiltration and immune function analysis were performed using “clusterProfiler” and “GSVA” packages in R. Results. The survival prediction model consisted of 9 miRNAs, namely, hsa-miR-1301, hsa-miR-940, hsa-miR-592, hsa-miR-3170, hsa-miR-876, hsa-miR-215, hsa-miR-934, hsa-miR-3920, and hsa-miR-216b. Survival of UCEC patients in the high-risk group was worse than that in the low-risk group ( $p<0.001$ ). The receiver operating characteristic (ROC) curve showed that the model had good predictive performance, and the area under the curve was 0.800, 0.690, and 0.705 for 1-, 3-, and 5-year survival predictions, respectively. There were differences in the degree of immune cell infiltration and immune activity between the low-risk and high-risk groups. The expression levels of the identified differentially expressed genes correlated with the susceptibility to multiple anticancer drugs. Conclusions. The survival prediction model constructed based on 9 m7G-related miRNAs had good predictive performance.

Molecular Targeting of the Most Functionally Complex Gene in Precision Oncology: p53

While chemotherapy is a key treatment strategy for many solid tumors, it is rarely curative, and most tumor cells eventually become resistant. Because of this, there is an unmet need to develop systemic treatments that capitalize on the unique mutational landscape of each patient's tumor. The most frequently mutated protein in cancer, p53, has a role in nearly all cancer subtypes and tumorigenesis stages and therefore is one of the most promising molecular targets for cancer treatment. Unfortunately, drugs targeting p53 have seen little clinical success despite promising preclinical data. Most of these drug compounds target specific aspects of p53 inactivation, such as through inhibiting negative regulation by the mouse double minute (MDM) family of proteins. These treatment strategies fail to address cancer cells' adaptation mechanisms and ignore the impact that p53 loss has on the entire p53 network. However, recent gene therapy successes show that targeting the p53 network and cellular dysfunction caused by p53 inactivation is now possible and may soon translate into successful clinical responses. In this review, we discuss p53 signaling complexities in cancer that have hindered the development and use of p53-targeted drugs. We also describe several current therapeutics reporting promising preclinical and clinical results.

DNA damage response revisited: the p53 family and its regulators provide endless cancer therapy opportunities

Antitumor therapeutic strategies that fundamentally rely on the induction of DNA damage to eradicate and inhibit the growth of cancer cells are integral approaches to cancer therapy. Although DNA-damaging therapies advance the battle with cancer, resistance, and recurrence following treatment are common. Thus, searching for vulnerabilities that facilitate the action of DNA-damaging agents by sensitizing cancer cells is an active research area. Therefore, it is crucial to decipher the detailed molecular events involved in DNA damage responses (DDRs) to DNA-damaging agents in cancer. The tumor suppressor p53 is active at the hub of the DDR. Researchers have identified an increasing number of genes regulated by p53 transcriptional functions that have been shown to be critical direct or indirect mediators of cell fate, cell cycle regulation, and DNA repair. Posttranslational modifications (PTMs) primarily orchestrate and direct the activity of p53 in response to DNA damage. Many molecules mediating PTMs on p53 have been identified. The anticancer potential realized by targeting these molecules has been shown through experiments and clinical trials to sensitize cancer cells to DNA-damaging agents. This review briefly acknowledges the complexity of DDR pathways/networks. We specifically focus on p53 regulators, protein kinases, and E3/E4 ubiquitin ligases and their anticancer potential.

p63, a key regulator of Ago2, links to the microRNA-144 cluster

Abstract

As a key component of the RNA-induced silencing complex (RISC), Argonaute2 (Ago2) exhibits a dual function regulatory role in tumor progression. However, the mechanistic basis of differential regulation remains elusive. p63 is a homolog of the tumor suppressor p53. p63 isoforms play a critical role in tumorigenesis and metastasis. Herein, we show that p63 isoforms physically interact with and stabilize Ago2. Expression of p63 isoforms increases the levels of Ago2 protein, while depletion of p63 isoforms by shRNA decreases Ago2 protein levels. p63 strongly guides Ago2 dual functions in vitro and in vivo. Ectopic expression of the miR-144/451 cluster increases p63 protein levels; TAp63 transactivates the miR-144/451 cluster, forming a positive feedback loop. Notably, miR-144 activates p63 by directly targeting Itch, an E3 ligase of p63. Ectopic expression of miR-144 induces apoptosis in H1299 cells. miR-144 enhances TAp63 tumor suppressor function and inhibits cell invasion. Our findings uncover a novel function of p63 linking the miRNA-144 cluster and the Ago2 pathway.

Facts and questions

Identification of Ago2 as a p63 target.

Ago2 exhibits a dual function regulatory role in tumor progression; however, the molecular mechanism of Ago2 regulation remains unknown.

p63 strongly guides Ago2 dual functions in vitro and in vivo.

Unraveling a novel function of p63 links the miRNA-144 cluster and the Ago2 pathway.

Establishment of a 4-miRNA Prognostic Model for Risk Stratification of Patients With Pancreatic Adenocarcinoma

Pancreatic adenocarcinomas (PAADs) often remain undiagnosed until later stages, limiting treatment options and leading to poor survival. The lack of robust biomarkers complicates PAAD prognosis, and patient risk stratification remains a major challenge. To address this issue, we established a panel constructed by four miRNAs (miR-4444-2, miR-934, miR-1301 and miR-3655) based on The Cancer Genome Atlas (TCGA) and Human Cancer Metastasis Database (HCMDB) to predicted the prognosis of PAAD patients. Then, a risk prediction model of these four miRNAs was constructed by using Cox regression analysis with the least absolute shrinkage and selection operator (LASSO) regression analysis. This model stratified TCGA PAAD cohort into the low-risk and high-risk groups based on the panel-based risk score, which was significantly associated with 1-, 2-, 3-year OS (AUC=0.836, AUC=0.844, AUC=0.952, respectively). The nomogram was then established with a robust performance signature for predicting prognosis compared to clinical characteristics of pancreatic cancer (PC) patients, including age, gender and clinical stage. Moreover, two GSE data were validated the expressions of 4 miRNAs with prognosis/survival outcome in PC. In the external clinical sample validation, the high-risk group with the upregulated expressions of miR-934/miR-4444-2 and downregulated expressions of miR-1301/miR-3655 were indicated a poor prognosis. Furthermore, the cell counting kit-8 (CCK-8) assay, clone formation, transwell and wound healing assay also confirmed the promoting effect of miR-934/miR-4444-2 and the inhibiting effect of miR-1301/miR-3655 in PC cell proliferation and migration. Taken together, we identified a new 4-miRNA risk stratification model could be used in predicting prognosis in PAAD.

Aberrant Expression of miR-1301 in Human Cancer

miR-1301 is a newly discovered miRNA, which is abnormally expressed in 14 types of tumors. miR-1301 inhibits 23 target genes, forms a ceRNA network with 2 circRNAs and 8 lncRNAs, and participates in 6 signaling pathways, thereby affecting tumor cell proliferation, invasion, metastasis, apoptosis, angiogenesis, etc. Abnormal expression of miR-1301 is often associated with poor prognosis of cancer patients. In addition, miR-1301 is related to the anti-tumor effect of epirubicin on osteosarcoma and imatinib on chronic myeloid leukemia(CML) and can enhance the cisplatin sensitivity of ovarian cancer. This work systematically summarizes the abnormal expression and prognostic value of miR-1301 in a variety of cancers, depicts the miR-1301-related signaling pathways and ceRNA network, and provides potential clues for future miR-1301 research.

The oncogenic role of HIF-1α/miR-182-5p/ZFP36L1 signaling pathway in nasopharyngeal carcinoma

Background

Accumulating evidence indicates that dysregulation of miR-182-5p can serve as diagnostic and prognostic biomarkers for some cancers, whereas the role of miR-182-5p has not been explored in nasopharyngeal carcinoma (NPC). Our study aims to elucidate the biological function of miR-182-5p in NPC and the potential molecular mechanism involved.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to determine miR-182-5p expression in NPC primary tissues and cell lines. Immunohistochemistry (IHC) for ZFP36L1 was conducted in NPC samples. Western blot was used to evaluate protein expression in cell lines. A series of functional assays were carried out to evaluate the roles of miR-182-5p and ZFP36L1 in tumor development and progression of NPC. Bioinformatics tools and luciferase reporter assays were utilized to identify the potential mechanisms of action. Moreover, rescue experiments were applied to explore whether ZFP36L1 mediated the effects of miR-182-5p in NPC.

Results

Up-regulation of miR-182-5p was significantly associated with tumor development and poor prognosis in patients with NPC. Functional study demonstrated that miR-182-5p overexpression enhanced, whereas suppression of miR-182-5p impeded NPC cell proliferation, migration, tumorigenesis and metastasis. Mechanistically, miR-182-5p interacted with ZFP36L1 at two sites in its 3′ un-translated region (UTR) and repressed ZFP36L1 expression in NPC. Consistently, an inverse correlation was observed between the expression levels of miR-182-5p and ZFP36L1 using clinical NPC tissues, and down-regulation of ZFP36L1 in NPC predicts poor survival. Furthermore, overexpression of miR-182-5p in NPC was partly attributable to the transcriptional activation effect induced by hypoxia-inducible factor 1α (HIF-1α).

Conclusions

Our data suggests that miR-182-5p facilitates cell proliferation and migration in NPC through its ability to down-regulate ZFP36L1 expression, and that the HIF-1α/miR-182-5p/ZFP36L1 axis may serve as a novel therapeutic target in the management of NPC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02177-3.

Decreased level of miR-1301 promotes colorectal cancer progression via activation of STAT3 pathway

The molecular pathogenesis of colorectal cancer (CRC) has been widely investigated in recent years. Accumulating evidence has indicated that microRNA (miRNA) dysregulation participates in the processes of driving CRC initiation and progression. Aberrant expression of miR-1301 has been found in various tumor types. However, its role in CRC remains to be elucidated. In the present study, we identified miR-1301 was enriched in normal colorectal tissues and significantly down-regulated in CRC. Decreased level of miR-1301 strongly correlated with aggressive pathological characteristics, including advanced stage and metastasis. Bioinformatics and dual luciferase assay demonstrated that STAT3 is a direct target of miR-1301. Gain and loss-of-function assays showed that miR-1301 had no effect on cell proliferation. Overexpression of miR-1301 suppressed cell migration and invasion capacity of pSTAT3-positive LoVo cells, but not pSTAT3-negative SW480 cells, while inhibition of miR-1301 consistently promoted cell migration and invasion in both cell lines. Additionally, miR-1301 inhibition restored the suppressed migration and invasion of STAT3-knockdown LoVo cells. MiR-1301 functioned as a tumor suppressor to modulate the IL6/STAT3 signaling pathway. In summary, this study highlights the significant role of miR-1301/STAT3 axis in CRC metastasis.

Hsp70 acts as a fine-switch that controls E3 ligase CHIP-mediated TAp63 and ΔNp63 ubiquitination and degradation

The major clinical problem in human cancer is metastasis. Metastases are the cause of 90% of human cancer deaths. TAp63 is a critical suppressor of tumorigenesis and metastasis. ΔNp63 acts as a dominant-negative inhibitor to block the function of p53 and TAp63. Although several ubiquitin E3 ligases have been reported to regulate p63 stability, the mechanism of p63 regulation remains partially understood. Herein, we show that CHIP, an E3 ligase with a U-box domain, physically interacts with p63 and promotes p63 degradation. Notably, Hsp70 depletion by siRNA stabilizes TAp63 in H1299 cells and destabilizes ΔNp63 in SCC9 cells. Loss of Hsp70 results in a reduction in the TAp63-CHIP interaction in H1299 cells and an increase in the interaction between ΔNp63 and CHIP in SCC9 cells. Our results reveal that Hsp70 acts as a molecular switch to control CHIP-mediated ubiquitination and degradation of p63 isoforms. Furthermore, regulation of p63 by the Hsp70-CHIP axis contributes to the migration and invasion of tumor cells. Hence, our findings demonstrate that Hsp70 is a crucial regulator of CHIP-mediated ubiquitination and degradation of p63 isoforms and identify a new pathway for maintaining TAp63 or ΔNp63 stability in cancers.

miR-1301-3p promotes the proliferation and migration of lung cancer cells via direct repression of polymerase I and transcript release factor

Aberrant expression of microRNAs (miRNAs or miRs) is associated with a number of human diseases, including lung cancer. Although numerous differentially expressed miRNAs have been identified in lung cancer via microarray and sequencing methods, to the best of our knowledge, only a small portion of these miRNAs have been experimentally verified. In the present study, miR-1301-3p expression levels in lung tumor tissues and lung cancer cells were measured by reverse transcription-quantitative PCR (RT-qPCR) and by analyzing previously published data. Cell Counting Kit-8 and Transwell assays were used to analyze the function of miR-1301-3p in lung cancer tissues and cells. Bioinformatics analysis, RT-qPCR, western blotting and a dual-luciferase reporter assay were performed to investigate the mechanism of miR-1301-3p in lung cancer cells. It was identified that miR-1301-3p is an upregulated miRNA in lung cancer via analyzing previously published microarray and The Cancer Genome Atlas-lung squamous cell carcinoma project data, and the upregulation of miR-1301-3p was confirmed in collected clinical samples and cells. Inhibition of miR-1301-3p suppressed lung cancer cell proliferation and migration. In addition, miR-1301-3p inhibition upregulated E-cadherin, an epithelial cell maker, and downregulated vimentin, a mesenchymal cell marker. Using bioinformatics analysis, it was revealed that polymerase I and transcript release factor (PTRF) is a target of miR-1301-3p. RT-qPCR, western blotting and dual-luciferase reporter assays demonstrated that PTRF is targeted by miR-1301-3p in lung cancer cells. The rescue experiments indicated that silencing PTRF could attenuate the inhibition of cell proliferation and migration induced by miR-1301-3p inhibitor in lung cancer cells. Furthermore, a strong negative correlation between miR-1301-3p and PTRF mRNA was identified in clinical samples. In summary, the present data highlight the involvement of miR-1301-3p in the proliferation and migration of lung cancer cells, indicating that miR-1301-3p may be a promising biomarker for lung cancer.

Potential miRNAs for miRNA-Based Therapeutics in Breast Cancer

MicroRNAs (miRNAs) are small non-coding RNAs that can post-transcriptionally regulate the genes involved in critical cellular processes. The aberrant expressions of oncogenic or tumor suppressor miRNAs have been associated with cancer progression and malignancies. This resulted in the dysregulation of signaling pathways involved in cell proliferation, apoptosis and survival, metastasis, cancer recurrence and chemoresistance. In this review, we will first (i) provide an overview of the miRNA biogenesis pathways, and in vitro and in vivo models for research, (ii) summarize the most recent findings on the roles of microRNAs (miRNAs) that could potentially be used for miRNA-based therapy in the treatment of breast cancer and (iii) discuss the various therapeutic applications.

RNA-Seq Profiling of Serum Exosomal Circular RNAs Reveals Circ-PNN as a Potential Biomarker for Human Colorectal Cancer

Circular RNAs (circRNAs) are emerging as cardinal areas of focus in the non-coding RNA field. Growing evidences have revealed exosomal circRNAs as potential biomarkers for detection of various cancers. However, the clinical importance of most serum exosomal circRNAs in colorectal cancer (CRC) have rarely been investigated. In this study, we examined the possible clinical application of serum exosomal circRNAs in the diagnosis of CRC. Firstly, we conducted RNA sequencing (RNA-seq) analysis using fifty CRC and fifty healthy control serum samples to identify CRC-related circRNAs. The sequencing data showed 122 differentially expressed circRNAs including 100 up-regulated and 22 down-regulated circRNA transcripts in CRC patients. Then, eight most dysregulated circRNAs were selected for validation by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assay. Validation analysis revealed that the serum exosomal circ-PNN (hsa_circ_0101802) levels were significantly up-regulated in CRC cases compared with those in the healthy control groups. Receiver operating characteristic curve (ROC) analysis suggested that circ-PNN had significant value in CRC diagnosis with areas under the ROC curve (AUC) of 0.855 and 0.826 in the training and validation sets, respectively. We also found that the AUC of serum exosomal circ-PNN for early-stage CRC was 0.854. Finally, a network map based on circ-PNN was constructed to determine its potential miRNA-mRNAs binding. We also demonstrated that the expression of hsa-miR-6833-3P, hsa-let-7i-3p and hsa-miR-1301-3P were negatively correlated with circ-PNN in CRC patients. Collectively, our findings indicated that serum exosomal circ-PNN might be a potential non-invasive biomarker for the detection of CRC and may play a crucial role in the pathogenesis of CRC.

The low expression of miR-1976 in plasma samples indicating its biological functions in the progression of breast cancer

BACKGROUND

The incidence of breast cancer (BC) is the highest among women. Identification of miRNAs as biomarkers may help to improve the diagnosis of BC. The purpose of this study was to assess the expression levels of miR-1976 in plasma samples and the biological functions in the progression of BC.

METHODS

The expression levels of miR-1976 in plasma samples and tissues were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The associations between the expression levels and clinicopathological features were studied. Cell supernatants were used to simulate circulation. The biological functions of miR-1976 were assessed in vitro and in vivo.

RESULTS

The expression levels of miR-1976 in plasma samples were found significantly lower in patients with BC than those in healthy controls, and were associated with Ki-67. The expression levels in BC tissues were lower than those in adjacent normal tissues, and were correlated with the number of lymph nodes and Ki-67. The expression levels in BC cell supernatants and cell lines were lower than that in normal human breast epithelial cell line HBL-100. miR-1976 knockdown promoted proliferation in vitro and in vivo.

CONCLUSION

miR-1976 may serve as a promising non-invasive biomarker for the diagnosis of BC in the future.

The Role of E3, E4 Ubiquitin Ligase (UBE4B) in Human Pathologies

The genome is exposed daily to many deleterious factors. Ubiquitination is a mechanism that regulates several crucial cellular functions, allowing cells to react upon various stimuli in order to preserve their homeostasis. Ubiquitin ligases act as specific regulators and actively participate among others in the DNA damage response (DDR) network. UBE4B is a newly identified member of E3 ubiquitin ligases that appears to be overexpressed in several human neoplasms. The aim of this review is to provide insights into the role of UBE4B ubiquitin ligase in DDR and its association with p53 expression, shedding light particularly on the molecular mechanisms of carcinogenesis.

MicroRNAs in cancer cell death pathways: Apoptosis and necroptosis

To protect tissues and the organism from disease, potentially harmful cells are removed through programmed cell death processes, including apoptosis and necroptosis. These types of cell death are critically controlled by microRNAs (miRNAs). MiRNAs are short RNA molecules that target and inhibit expression of many cellular regulators, including those controlling programmed cell death via the intrinsic (Bcl-2 and Mcl-1), extrinsic (TRAIL and Fas), p53-and endoplasmic reticulum (ER) stress-induced apoptotic pathways, as well as the necroptosis cell death pathway. In this review, we discuss the current knowledge of apoptosis and necroptosis pathways and how these are impaired in cancer cells. We focus on how miRNAs disrupt apoptosis and necroptosis, thereby critically contributing to malignancy. Understanding which and how miRNAs and their targets affect cell death pathways could open up novel therapeutic opportunities for cancer patients. Indeed, restoration of pro-apoptotic tumor suppressor miRNAs (apoptomiRs) or inhibition of oncogenic miRNAs (oncomiRs) represent strategies that are currently being trialed or are already applied as miRNA-based cancer therapies. Therefore, better understanding the cancer type-specific expression of apoptomiRs and oncomiRs and their underlying mechanisms in cell death pathways will not only advance our knowledge, but also continue to provide new opportunities to treat cancer.

Gene expression alterations of human liver cancer cells following borax exposure

Borax is a boron compound that is becoming widely recognized for its biological effects, including lipid peroxidation, cytotoxicity, genotoxicity, antioxidant activity and potential therapeutic benefits. However, it remains unknown whether exposure of human liver cancer (HepG2) cells to borax affects the gene expression of these cells. HepG2 cells were treated with 4 mM borax for either 2 or 24 h. Gene expression analysis was performed using Affymetrix GeneChip Human Gene 2.0 ST Arrays, which was followed by gene ontology analysis and pathway analysis. The clustering result was validated using reverse transcription-quantitative polymerase chain reaction. A cell proliferation assay was performed using Celigo Image Cytometer Instrumentation. Following this, 2- or 24-h exposure to borax significantly altered the expression level of a number of genes in HepG2 cells, specifically 530 genes (384 upregulated and 146 downregulated) or 1,763 genes (1,044 upregulated and 719 downregulated) compared with the control group, respectively (≥2-fold; P<0.05). Twenty downregulated genes were abundantly expressed in HepG2 cells under normal conditions. Furthermore, the growth of HepG2 cells was inhibited through the downregulation of PRUNE1, NBPF1, PPcaspase-1, UPF2 and MBTPS1 (≥1.5-fold, P<0.05). The dysregulated genes potentially serve important roles in various biological processes, including the inflammation response, stress response, cellular growth, proliferation, apoptosis and tumorigenesis/oncolysis.

MicroRNA-498 promotes proliferation and migration by targeting the tumor suppressor PTEN in breast cancer cells

Triple negative breast cancer (TNBC) is a subtype of breast cancer with a poor prognosis and high mortality rate. The tumor suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN) plays an important role in cell proliferation and cell migration by negatively regulating the PI3K/Akt pathway. PTEN is downregulated by microRNAs in multiple cancers. However, few microRNAs have been reported to directly target PTEN in TNBC. In this study, microRNAs predicted to target PTEN were screened by immunoblotting and luciferase reporter assays. Expression levels of microRNA-498 (miR-498) were measured by TaqMan microRNA assays. We performed clonogenic, cell cycle and scratch wound assays to examine the oncogenic role of miR-498. We demonstrated that miR-498 directly targeted the 3'untranslated region of PTEN mRNA and reduced PTEN protein levels in TNBC cells. Compared with the non-tumorigenic breast epithelial cell line MCF-10A, TNBC cell lines overexpressed miR-498. Moreover, miR-498 promoted cell proliferation and cell cycle progression in TNBC cells in a PTEN-dependent manner. Suppressing miR-498 overexpression impaired the oncogenic effects of miR-498 on cell proliferation and cell migration. This study identified a novel microRNA (miR-498) overexpressed in TNBC cells and its oncogenic role in suppressing PTEN. These results provide new insight into the downregulation of PTEN and indicate a potential therapeutic target for treating TNBC.

Jianpi Jiedu decoction, a traditional Chinese medicine formula, inhibits tumorigenesis, metastasis, and angiogenesis through the mTOR/HIF-1α/VEGF pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine has been utilized for the treatment of cancer. Jianpi Jiedu decoction (JPJD), a traditional Chinese medicine formula, has been used for the treatment of colorectal cancer for decades. However, the underlying molecular mechanistic basis for the effect of JPJD on colorectal cancer is poorly understood.

AIM OF THE STUDY

The aim of this study was to identify the effects of JPJD on human colon cancer cells in vitro as well as in vivo and to investigate the mechanistic basis for the anticancer effect of JPJD.

MATERIALS AND METHODS

The in vitro antitumor activity of JPJD was assessed by MTT assay, flow cytometric analysis, wound-healing assay, transwell assays, and tube formation assays in order to assess cell activity, apoptosis, migration, invasion, and angiogenesis, respectively. The anticancer properties of JPJD in vivo were assessed by immunohistochemistry in a nude mouse xenograft model of HCT116 cells. In addition, the level of mTOR/HIF-1α/VEGF signaling pathway proteins in HCT116 cells and tumor tissue was evaluated by immunoblotting.

RESULTS

In vitro, JPJD significantly inhibited colorectal cancer cell lines viability and proliferation. Flow cytometry analysis demonstrated JPJD to induce HCT116 cell apoptosis. Additionally, JPJD effectively suppressed tumor cell migration, invasion, and angiogenesis by inhibiting the mTOR/HIF-1α/VEGF signaling pathway. In vivo, JPJD significantly inhibited HCT116 tumor growth in athymic nude mice, decreased the levels of CD34 as well as VEGF, and downregulated the mTOR/HIF-1α/VEGF pathway.

CONCLUSIONS

JPJD treatment produced anti-colorectal tumor effects by inhibiting tumorigenesis, metastasis, as well as angiogenesis through the mTOR/HIF-1α/VEGF pathway. Thus, these results provide a strong rationale for the therapeutic use of JPJD in cancer treatment. Further studies are required to investigate the mechanisms underlying anti-CRC effect of JPJD.

MicroRNA-1301 inhibits migration and invasion of osteosarcoma cells by targeting BCL9

Increasing reports demonstrated that miRNAs play a critical role in tumor development and progression. Previous studies revealed that miR-1301 was abnormally expressed in various cancers. However, its function and underlying mechanism in osteosarcoma (OS) remains unknown. In this study, miR-1301 expression was significantly down-regulated in both OS tissues and cell lines. Down-regulated miR-1301 was obviously associated with malignant clinical features and poor overall survival of OS patients. miR-1301 overexpression inhibited cell proliferation, migration and invasion. In addition, we identified BCL9 act as a direct target of miR-1301 by directly binding to its 3'-UTR. In clinical OS tissues, miR-1301 negatively correlated BCL9 expression. BCL9 was up-regulated in OS tissues and cells. BCL9 overexpression promoted OS progression. Moreover, restoration of BCL9 expression at least partially abolished the proliferation, migration and invasion of miR-1301 on OS cells. In conclusion, our data indicated that miR-1301 inhibited cell proliferation, migration and invasion of OS by targeting BCL9, and may represent a novel potential therapeutic target and prognostic marker for OS.

miR-1301-3p promotes prostate cancer stem cell expansion by targeting SFRP1 and GSK3β

Cancer stem cells promote tumor progression, drug-resistance, and relapse, and many microRNAs (miRNAs) play critical roles in the expansion of cancer stem cells. In the present study, we investigated the role of miR-1301-3p in the expansion of prostate cancer stem cells; miR-1301-3p was significantly upregulated in prostate cancer cells and tissues compared with normal prostate cells and tissues. Sphere formation and side population assays suggested that miR-1301-3p promoted the expansion of prostate cancer stem cells, and increased the expression of prostate cancer stem cell-associated genes, such as OCT4, SOX2, NANOG, CD44, KLF4, c-MYC, and MMP2. MiR-1301-3p targeted Wnt pathway inhibitors, GSK3β and SFRP1, and inhibited their expression by directly binding to their 3' untranslated regions. TOP/FOP luciferase assays suggested that miR-1301-3p activated the Wnt pathway, which was confirmed by increased β-catenin expression in the nucleus. Furthermore, the miR-1301-3p level correlated negatively with GSK3β and SFRP1 in prostate cancer tissues. In summary, we found that miR-1301-3p promoted the expansion of prostate cancer stem cells by inhibiting GSK3β and SFRP1, and activating the Wnt pathway.

EZH2 induces the expression of miR-1301 as a negative feedback control mechanism in triple negative breast cancer

Breast cancer is one of the most common malignancies in women. ERα, PR, and HER2 triple negative breast cancer (TNBC) is the current research focus because of the lack of effective targeted therapies. In our study, lentivirus systems were used to overexpress EZH2 and miR-1301 in TNBC cell lines. Western blot analysis and RT-qPCR were used to detect the protein and microRNA levels. The TCGA and Kaplan Meier plotter databases were used to analyze the EZH2 and miR-1301 expression levels in breast cancer. The effect of miR-1301 overexpression on cell proliferation, migration and colony formation were determined by using the sulforhodamine B (SRB) assay, wound healing assay and colony formation assay, respectively. Furthermore, an xenograft mouse model was used to investigate the function of miR-1301 overexpression in vivo. Finally, dual luciferase reporter assay was used to verify the binding site of EZH2 and miR-1301. We found that EZH2 induced the expression of miR-1301 in two TNBC cell lines, HCC1937 and HCC1806. Overexpression of miR-1301 suppressed TNBC cell proliferation, migration and colony formation, as well as the xenograft tumor growth in immunodeficient mice. Interestingly, miR-1301 inhibited the expression of EZH2 by binding to the 3'-UTR of EZH2 gene. These data suggest that EZH2 induces the expression of miR-1301 as a negative feedback control mechanism in TNBC.

The distinct role of strand-specific miR-514b-3p and miR-514b-5p in colorectal cancer metastasis

The abnormal expression of microRNAs (miRNAs) in colorectal cancer (CRC) progression has been widely investigated. It was reported that the same hairpin RNA structure could generate mature products from each strand, termed 5p and 3p, which binds different target mRNAs. Here, we explored the expression, functions, and mechanisms of miR-514b-3p and miR-514b-5p in CRC cells and tissues. We found that miR-514b-3p was significantly down-regulated in CRC samples, and the ratio of miR-514b-3p/miR-514b-5p increased from advanced CRC, early CRC to matched normal colorectal tissues. Follow-up functional experiments illustrated that miR-514b-3p and miR-514b-5p had distinct effects through interacting with different target genes: MiR-514b-3p reduced CRC cell migration, invasion and drug resistance through increasing epithelial marker and decreasing mesenchymal marker expressions, conversely, miR-514b-5p exerted its pro-metastatic properties in CRC by promoting EMT progression. MiR-514b-3p overexpressing CRC cells developed tumors more slowly in mice compared with control cells, however, miR-514b-5p accelerated tumor metastasis. Overall, our data indicated that though miR-514b-3p and miR-514b-5p were transcribed from the same RNA hairpin, each microRNA has distinct effect on CRC metastasis.

MicroRNA‑4284 promotes gastric cancer tumorigenicity by targeting ten-eleven translocation 1

Increasing evidence has shown that abnormal expression of miR-4284 participates in the progression of several types of cancer. However, the expression and the role of miR-4284 in gastric cancer remain largely unknown. Therefore, in the present study the miR-4284 expression levels in gastric cancer tissues and cell lines, was examined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and found that miR-4284 was significantly upregulated in 40 pairs of gastric cancer tissues and five gastric cancer cell lines compared to the corresponding normal tissues and GES-1 cell line. In addition, increased miR-4284 expression was positively associated with TNM stage (P=0.035), distal metastasis (P=0.022) and poor prognosis in gastric cancer patients. Furthermore, the overexpression of miR-4284 expression was shown to promote cell proliferation, clone formation, invasion and migration, while the suppression of miR-4284 expression induced opposite effects. Additionally, luciferase reporter assay was conducted and showed that ten-eleven translocation 1 (TET1), a tumor suppressor gene that regulating cell survival and metastasis, was a direct target of miR-4284. Upregulated miR-4284 decreased the mRNA and protein levels of TET1 in SGC-7901 cells and downregulated miR-4284 increased the mRNA and protein levels of TET1 in AGS cells. In addition, miR-4284 expression was negatively correlated with the TET1 expression in gastric cancer tissues. Moreover, inhibition of TET1 suppressed the effect of miR-4284 inhibitors on cell proliferation in AGS cells. Therefore, data demonstrated that miR-4284 could promote tumor cell growth, migration and invasion by directly targeting TET1 in gastric cancer, which may provide a potential therapeutic target for gastric cancer treatment.

MicroRNAs in cancer metastasis and angiogenesis

Cancer metastasis is a malignant process by which tumor cells migrate from their primary site of origin to other organs. It is the main cause of poor prognosis in cancer patients. Angiogenesis is the process of generating new blood capillaries from pre-existing vasculature. It plays a vital role in primary tumor growth and distant metastasis. MicroRNAs are small non-coding RNAs involved in regulating normal physiological processes as well as cancer pathogenesis. They suppress gene expression by specifically binding to the 3′-untranslated region (3′-UTR) of their target genes. They can thus act as oncogenes or tumor suppressors depending on the function of their target genes. MicroRNAs have shown great promise for use in anti-metastatic cancer therapy. In this article, we review the roles of various miRNAs in cancer angiogenesis and metastasis and highlight their potential for use in future therapies against metastatic cancer.

miR-342-3p suppresses cell proliferation and migration by targeting AGR2 in non-small cell lung cancer

AGR2 is a well-studied secreted protein that is involved in multiple biological processes including cell proliferation and migration. The mechanism by which AGR2 increases the growth and migration of non-small cell lung cancer cells (NSCLC) is still unknown. In this study, we report that AGR2 is directly targeted by miR-342-3p. Functional studies suggest that overexpression of miR-342-3p inhibits the proliferation and migration of non-small cell lung cancer cells. Overexpression of AGR2 counteracts the phenotypes induced by miR-342-3p. Moreover, AGR2 expression is up-regulated and negatively correlated with miR-342-3p levels in NSCLC cells and tissues. A meta-analysis of survival data indicates that NSCLC patients with high levels of AGR2 in their tumors have a worse prognosis. Collectively, the identification of miR-342-3p and AGR2 might facilitate the development of biomarkers and therapeutic targets for this devastating disease.