MicroR-760 suppresses cancer stem cell subpopulation and breast cancer cell proliferation and metastasis: By down-regulating NANOG

Crosstalk between lipid metabolism and EMT: emerging mechanisms and cancer therapy

Lipids are the key component of all membranes composed of a variety of molecules that transduce intracellular signaling and provide energy to the cells in the absence of nutrients. Alteration in lipid metabolism is a major factor for cancer heterogeneity and a newly identified cancer hallmark. Reprogramming of lipid metabolism affects the diverse cancer phenotypes, especially epithelial-mesenchymal transition (EMT). EMT activation is considered to be an essential step for tumor metastasis, which exhibits a crucial role in the biological processes including development, wound healing, and stem cell maintenance, and has been widely reported to contribute pathologically to cancer progression. Altered lipid metabolism triggers EMT and activates multiple EMT-associated oncogenic pathways. Although the role of lipid metabolism-induced EMT in tumorigenesis is an attractive field of research, there are still significant gaps in understanding the underlying mechanisms and the precise contributions of this interplay. Further study is needed to clarify the specific molecular mechanisms driving the crosstalk between lipid metabolism and EMT, as well as to determine the potential therapeutic implications. The increased dependency of tumor cells on lipid metabolism represents a novel therapeutic target, and targeting altered lipid metabolism holds promise as a strategy to suppress EMT and ultimately inhibit metastasis.

Cancer stem cells: The important role of CD markers, Signaling pathways, and MicroRNAs

For the first time, a subset of small cancer cells identified in acute myeloid leukemia has been termed Cancer Stem Cells (CSCs). These cells are notorious for their robust proliferation, self-renewal abilities, significant tumor-forming potential, spread, and resistance to treatments. CSCs are a global concern, as it found in numerous types of cancer, posing a real-world challenge today. Our review encompasses research on key CSC markers, signaling pathways, and MicroRNA in three types of cancer: breast, colon, and liver. These factors play a critical role in either promoting or inhibiting cancer cell growth. The reviewed studies have shown that as cells undergo malignant transformation, there can be an increase or decrease in the expression of different Cluster of Differentiation (CD) markers on their surface. Furthermore, alterations in essential signaling pathways, such as Wnt and Notch1, may impact CSC proliferation, survival, and movement, while also providing potential targets for cancer therapies. Additionally, some research has focused on MicroRNAs due to their dual role as potential therapeutic biomarkers and their ability to enhance CSCs' response to anti-cancer drugs. MicroRNAs also regulate a wide array of cellular processes, including the self-renewal and pluripotency of CSCs, and influence gene transcription. Thus, these studies indicate that MicroRNAs play a significant role in the malignancy of various tumors. Although the gathered information suggests that specific CSC markers, signaling pathways, and MicroRNAs are influential in determining the destiny of cancer cells and could be advantageous for therapeutic strategies, their precise roles and impacts remain incompletely defined, necessitating further investigation.

Methods for assessing the effect of microRNA on stemness genes

According to the latest concepts, for micrometastasis to develop into macrometastasis, differentiated cancer cells must revert to a dedifferentiated state. Activation of stemness genes plays a key role in this transition. Suppression of stemness gene expression using microRNAs can become the basis for the development of effective anti-metastatic drugs. This article provides an overview of the existing methods for assessing the effect of microRNAs on stemness genes and cancer cell dedifferentiation.

Reciprocal interplays between MicroRNAs and pluripotency transcription factors in dictating stemness features in human cancers

The interplay between microRNAs (miRNAs) and pluripotency transcription factors (TFs) orchestrates the acquisition of cancer stem cell (CSC) features during the course of malignant transformation, rendering them essential cancer cell dependencies and therapeutic vulnerabilities. In this review, we discuss emerging themes in tumor heterogeneity, including the clonal evolution and the CSC models and their implications in resistance to cancer therapies, and then provide thorough coverage on the roles played by key TFs in maintaining normal and malignant stem cell pluripotency and plasticity. In addition, we discuss the reciprocal interactions between miRNAs and MYC, OCT4, NANOG, SOX2, and KLF4 pluripotency TFs and their contributions to tumorigenesis. We provide our view on the potential to interfere with key miRNA-TF networks through the use of RNA-based therapeutics as single agents or in combination with other therapeutic strategies, to abrogate the CSC state and render tumor cells more responsive to standard and targeted therapies.

METTL1 drives tumor progression of bladder cancer via degrading ATF3 mRNA in an m7G-modified miR-760-dependent manner

7-methylguanosine (m⁷G) modification is recently found to conservatively exist in RNA internal position besides mRNA caps and mediates the various RNA metabolisms. As the core confirmed transmethylase of m⁷G modification, METTL1 has been reported in certain human cancers. However, the role of internal m⁷G at miRNAs and its core writer METTL1 in bladder cancer (BCa) remains to be elucidated. Here, we demonstrated that METTL1 was indispensable for BCa proliferation and metastasis in vitro and in vivo. By combining miRNA sequencing, m⁷G methylated RNA immunoprecipitation (MeRIP) and RIP, we identified METTL1 promoted the processing of miR-760 in an m⁷G-dependent manner. Transcription sequencing suggested that METTL1 indirectly degrades tumor suppressor ATF3 mRNA mediated by miR-760. Together, we concluded a regulatory axis composed of METTL1/m⁷G/miR-760/ATF3 in regulating BCa progression and provided potential therapeutic targets for BCa.

Advances in Biomarkers and Endogenous Regulation of Breast Cancer Stem Cells

Breast cancer is one of the most common cancers. Even if breast cancer patients initially respond to treatment, developed resistance can lead to a poor prognosis. Cancer stem cells (CSCs) are a group of undifferentiated cells with self-renewal and multipotent differentiation characteristics. Existing evidence has shown that CSCs are one of the determinants that contribute to the heterogeneity of primary tumors. The emergence of CSCs causes tumor recurrence, metastasis, and therapeutic resistance. Previous studies indicated that different stemness-associated surface markers can identify other breast cancer stem cell (BCSC) subpopulations. Deciphering the critical signaling networks that are involved in the induction and maintenance of stemness is essential to develop novel BCSC-targeting strategies. In this review, we reviewed the biomarkers of BCSCs, critical regulators of BCSCs, and the signaling networks that regulate the stemness of BCSCs.

CCL18 promotes breast cancer progression by exosomal miR-760 activation of ARF6/Src/PI3K/Akt pathway

The small GTPase ADP-ribosylation factor 6 (ARF6) mediates chemokine (C-C motif) ligand 18 (CCL18)-induced activation of breast cancer (BC) metastasis through its downstream effector AMAP1. However, the molecular mechanisms underlying CCL18 up-regulating ARF6 remain largely unclear. Here, microRNAs (miRNAs) that target ARF6 were predicted and selected in high metastatic BC cells treated with CCL18. Next, we assessed the role of exosomal miR-760 in vitro and in vivo. We further analyzed the expression of ARF6, AMAP1, and phosphorylated (p)-AMAP1 in tumor and adjacent normal tissues. We first observed that CCL18 increased the expression of ARF6 and p-AMAP1 and activated the Src/phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. ARF6 knockdown significantly impaired CCL18-induced malignant cellular behaviors and the Src/PI3K/Akt signaling pathway. Next, ARF6 was confirmed as a target gene of miR-760 in exosomes derived from CCL18-stimulated high metastatic BC cells. Moreover, recipient MCF-7 cells could effectively uptake these miR-760-rich exosomes that significantly promoted proliferation, tumor growth in vivo, migration, invasion, and chemoresistance by activating ARF6-mediated Src/PI3K/Akt signaling and the epithelial-mesenchymal transition (EMT) pathway. Together, our results support that exosomal miR-760 secreted by CCL18-stimulated high metastatic BC cells promoted the malignant behaviors in low metastatic BC cells by up-regulating the ARF6-mediated Src/PI3K/Akt signaling pathway.

Nanog, as a key cancer stem cell marker in tumor progression

Cancer stem cells (CSCs) are a small population of malignant cells that induce tumor onset and development. CSCs share similar features with normal stem cells in the case of self-renewal and differentiation. They also contribute to chemoresistance and metastasis of cancer cells, leading to therapeutic failure. To identify CSCs, multiple cell surface markers have been characterized, including Nanog, which is found at high levels in different cancers. Recent studies have revealed that Nanog upregulation has a substantial association with the advanced stages and poor prognosis of malignancies, playing a pivotal role through tumorigenesis of multiple human cancers, including leukemia, liver, colorectal, prostate, ovarian, lung, head and neck, brain, pancreatic, gastric and breast cancers. Nanog through different signaling pathways, like JAK/STAT and Wnt/β-catenin pathways, induces stemness, self-renewal, metastasis, invasiveness, and chemoresistance of cancer cells. Some of these signaling pathways are common in various types of cancers, but some have been found in one or two cancers. Therefore, this review aimed to focus on the function of Nanog in multiple cancers based on recent studies surveying the suitable approaches to target Nanog and inhibit CSCs residing in tumors to gain favorable results from cancer treatments.

Linc01133 promotes proliferation and metastasis of human renal cell carcinoma through sponging miR-760

Renal cell carcinoma (RCC) is one of the most frequent human tumors and has brought great threats to the health of the people around the globe. It was reported that linc01133, a long non-coding RNA (lncRNA), was involved in the pathogenesis and development of several human cancer. But the biological role of linc01133 in RCC is still not understood. The present study aimed to investigate the biological functions of linc01133 in RCC. We did some biological experiments in this study, including quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, MTT assay, wound healing assay, Transwell invasion assay and xenograft tumor assay. In this study, we found the expression levels of linc01133 markedly increased in the RCC tissues compared with the normal tissues. And we found that the over-expressing of linc01133 promoted cell proliferation, migration and invasion, the interfering of linc01133 inhibited cell proliferation, migration and invasion. Furthermore, we found that the interfering of linc01133 inhibited tumor growth in murine xenograft models. Additionally, we found that linc01133 promotes RCC cell proliferation, migration and invasion through sponging miR-760. Collectively, our work preliminarily illuminated the tumor-promoting role of linc01133 in RCC and the potential molecular mechanism. Thus, our study may provide some evidence for the treatment of RCC.

Long Non-coding RNA FOXD2-AS1 Promotes Proliferation, Migration, and Invasion in Cholangiocarcinoma Through Regulating miR-760/E2F3 Axis

BACKGROUND

Long non-coding RNA (lncRNA) has been testified to influence the initiation and evolution of sundry carcinomas. Recently, lncRNA FOXD2 adjacent opposite strand RNA 1 (FOXD2-AS1) has been found to display vital regulating functions in various cancers.

METHODS

qRT-PCR was used to verify the dysregulation of FOXD2-AS1 expression in CCA cells and tissues, and the correlation of FOXD2-AS1 expression with clinicopathological characteristics was investigated. The viability, migration, and invasion of CCA cells were verified through CCK-8 assay, colony formation experiment, wound healing assay, and transwell assay. The regulatory networks of FOXD2-AS1 were analyzed by Bioinformatic prediction and dual-luciferase reporter assay.

RESULTS

We discovered that FOXD2-AS1 was significantly upregulated in CCA and its up-regulation was closely correlated with terminal TNM stage, lymph node metastasis and poor survival in the current research. In addition, it was revealed that FOXD2-AS1 was an independent prognostic factor. Functional tests uncovered that the cell viability, migration, and invasion could be restrained through downregulating the expression of FOXD2-AS1, while FOXD2-AS1 overexpression could facilitate the cell viability, migration, and invasion. Mechanistically, FOXD2-AS1 was founded to interact directly with miR-760 and the oncogene E2F3 was the downstream target of miR-760 through bioinformatic prediction and dual-luciferase reporter assays. Finally, we testified that FOXD2-AS1 could competitively sponge miR-760 and further upregulated the E2F3 expression to play a vital part in cholangiocarcinoma.

CONCLUSIONS

This research revealed that lncRNA FOXD2-AS1 could enhance CCA malignant progression through regulating the miR-760/E2F3 axis and was expected to be a prognostic biomarker and therapeutic target for cholangiocarcinoma.

Hyaluronidase and pH Dual-Responsive Nanoparticles for Targeted Breast Cancer Stem Cells

pH-responsive and CD44 receptor-mediated targeted nanoparticles for eliminating cancer stem cells (CSCs) were developed based on complexes of PEG-poly(β-amino ester) (PEG-PBAE) micelles (PPM) coated with hyaluronic acid (HA) (HA-coated PPM complex, or HPPMc). Thioridazine (Thz) was loaded into HPPMc with a decent drug loading content. The release results of the drug in vitro showed that Thz was released from the HPPMc, which was stimulated by both the acidic pH and specific enzymes. Cytotoxicity studies on mammospheres (MS) revealed that the toxicity potential of Thz-loaded HPPMc (Thz–HPPMc) at pH 5.5 was better than drug solutions. Compared with that at pH 7.4, a higher cellular uptake of a coumarin-6 (C6)-labeled complex at pH 5.5 was observed, which demonstrated that complexes were efficiently taken up in MS. Meanwhile, free HA competitively inhibited the cellular uptake of HPPMc, which revealed that the uptake mechanism was CD44 receptor-mediated endocytosis. Within the acidic endolysosomal environment, the protonation of PBAE facilitated the escape of the complex from the lysosome and releases the drug. The results of in vivo distribution studies and tumor suppression experiments showed that HPMMc could stay in the tumor site of BALB/c nude mice for a longer period of time, and Thz–HPPMc could significantly improve the tumor-suppressing effect. All these results demonstrated the great potential of the multifunctional nanoparticle system for eliminating CSCs.

The Alterations and Potential Roles of MCMs in Breast Cancer

The minichromosome maintenance (MCM) protein family plays a key role in eukaryotic DNA replication and has been confirmed to be associated with the occurrence and progression of many tumors. However, the expression levels, functions, and prognostic values of MCMs in breast cancer (BC) have not been clearly and systematically explained. In this article, we studied the transcriptional levels of MCMs in BC based on the Oncomine database. Kaplan-Meier plotter was used to analyze prognostic value of MCMs in human BC patients. Furthermore, we constructed a MCM coexpression gene network and performed functional annotation analysis through DAVID to reveal the functions of MCMs and coexpressed genes. The data showed that the expression of MCM2–8 and MCM10 but not MCM1 and MCM9 was upregulated in BC. Kaplan-Meier plotter analysis revealed that high transcriptional levels of MCM2, MCM4–7, and MCM10 were significantly related to low relapse-free survival (RFS) in BC patients. In contrast, high levels of MCM1 and MCM9 predicted high RFS for BC patients. This study suggests that MCM2, MCM4–7, and MCM10 possess great potential to be valuable prognostic biomarkers for BC and that MCM1 and MCM9 may serve as potential treatment targets for BC patients.

Competing Endogenous RNA Networks in Glioma

Gliomas are the most common and malignant primary brain tumors. Various hallmarks of glioma, including sustained proliferation, migration, invasion, heterogeneity, radio- and chemo-resistance, contribute to the dismal prognosis of patients with high-grade glioma. Dysregulation of cancer driver genes is a leading cause for these glioma hallmarks. In recent years, a new mechanism of post-transcriptional gene regulation was proposed, i.e., "competing endogenous RNA (ceRNA)." Long non-coding RNAs, circular RNAs, and transcribed pseudogenes act as ceRNAs to regulate the expression of related genes by sponging the shared microRNAs. Moreover, coding RNA can also exert a regulatory role, independent of its protein coding function, through the ceRNA mechanism. In the latest glioma research, various studies have reported that dysregulation of certain ceRNA regulatory networks (ceRNETs) accounts for the abnormal expression of cancer driver genes and the establishment of glioma hallmarks. These achievements open up new avenues to better understand the hidden aspects of gliomas and provide new biomarkers and potential efficient targets for glioma treatment. In this review, we summarize the existing knowledge about the concept and logic of ceRNET and highlight the emerging roles of some recently found ceRNETs in glioma progression.

miR-760 mediated the proliferation and metastasis of hepatocellular carcinoma cells by regulating HMGA2

BACKGROUND

The purpose of our study was to investigate the roles of miR-760 and its potential mechanisms in HCC.

METHODS

The functions of miR-760 were identified and measured by MTT, colony formation, transwell, and flow cytometry assays. Luciferase assay was applied to verify the direct binding of miR-760 on HMGA2 3'untranslated region (3'UTR). Then, in vitro experiment was used to investigate the biological effects of miR-760 and HMGA2. Luciferase and ChIP assays were used to detect the validity of SP1 binding sites on the miR-760 promoter.

RESULTS

We demonstrated that miR-760 overexpression suppressed cell proliferation, migration, and invasion in HCC. Besides, HMGA2 was demonstrated as a direct target gene of miR-760. Furthermore, we found that methylation may result in the downregulation of miR-760, and SP1 could inhibit the transcription of miR-760.

CONCLUSIONS

Our study demonstrated that SP1/miR-760/HMGA2 may serve as a molecular regulatory axis for HCC treatment.

Identification of potential key genes and miRNAs involved in Hepatoblastoma pathogenesis and prognosis

Hepatoblastoma (HB) is one of the most common liver malignancies in children, while the molecular basis of the disease is largely unknown. Therefore, this study aims to explore the key genes and molecular mechanisms of the pathogenesis of HB using a bioinformatics approach. The gene expression dataset GSE131329 was used to find differentially expressed genes (DEGs). Functional and enrichment analyses of the DEGs were performed by the EnrichR. Then, the protein-protein interaction (PPI) network of the up-regulated genes was constructed and visualized using STRING database and Cytoscape software, respectively. MCODE was used to detect the significant modules of the PPI network, and cytoHubba was utilized to rank the important nodes (genes) of the PPI modules. Overall, six ranking methods were employed and the results were validated by the Oncopression database. Moreover, the upstream regulatory network and the miRNA-target interactions of the up-regulated DEGs were analyzed by the X2K web and the miRTarBase respectively. A total of 594 DEGs, including 221 up- and 373 down-regulated genes, were obtained, which were enriched in different cellular and metabolic processes, human diseases, and cancer. Furthermore, 15 hub genes were screened, out of which, 11 were validated. Top 10 transcription factors, kinases, and miRNAs were also determined. To the best of our knowledge, the association of RACGAP1, MKI67, FOXM1, SIN3A, miR-193b, and miR-760 with HB was reported for the first time. Our findings may be used to shed light on the underlying mechanisms of HB and provide new insights for better prognosis and therapeutic strategies.

Nitric oxide-targeted therapy inhibits stemness and increases the efficacy of tamoxifen in estrogen receptor-positive breast cancer cells

Cancer stem cells (CSCs) are involved in the resistance of estrogen (ER)-positive breast tumors against endocrine therapy. On the other hand, nitric oxide (NO) plays a relevant role in CSC biology, although there are no studies addressing how this important signaling molecule may contribute to resistance to antihormonal therapy in ER+ breast cancer. Therefore, we explored whether targeting NO in ER+ breast cancer cells impacts CSC subpopulation and sensitivity to hormonal therapy with tamoxifen. NO was targeted in ER+ breast cancer cells by specific NO depletion and NOS2 silencing and mammosphere formation capacity, stem cell markers and tamoxifen sensitivity were analyzed. An orthotopic breast tumor model in mice was also performed to analyze the efficacy of NO-targeted therapy plus tamoxifen. Kaplan-Meier curves were made to analyze the association of NOS2 gene expression with survival of ER+ breast cancer patients treated with tamoxifen. Our results show that targeting NO inhibited mamosphere formation, CSC markers expression and increased the antitumoral efficacy of tamoxifen in ER+ breast cancer cells, whereas tamoxifen-resistant cells displayed higher expression levels of NOS2 and Notch-1 compared with parental cells. Notably, NO-targeted therapy plus tamoxifen was more effective than either treatment alone in an orthotopic breast tumor model in immunodeficient mice. Furthermore, low NOS2 expression was significantly associated with a higher metastasis-free survival in ER+ breast cancer patients treated with tamoxifen. In conclusion, our data support that NO-targeted therapy in ER+ breast cancer may contribute to increase the efficacy of antihormonal therapy avoiding the development of resistance to these treatments.

MicroRNA-760 inhibits cell viability and migration through down-regulating BST2 in gastric cancer

Gastric cancer is one of the most common types of carcinoma with a threat to global health. MicroRNA-760 (miR-760) was significantly down-regulated in the primary tumour of patients with advanced gastric cancer. However, the role of miR-760 in gastric cancer is still unclear. Herein, miR-760 was down-regulated in gastric cancer tissues. Moreover, miR-760 overexpression and knockdown were conducted in gastric cancer cells (MGC-803 and SGC-7901) in vitro. The in vitro functional assays proved that miR-760 overexpression reduced cell viability, cell cycle, migration and invasion, promoted apoptosis and suppressed MMP activity in MGC-803 cells. Conversely, miR-760 knockdown led to the opposite in SGC-7901 cells. Notably, bone marrow stromal antigen 2 (BST2) was verified as a target gene of miR-760. MiR-760 mimics down-regulated BST2 level in gastric cancer tissues and in MGC-803 cells, whereas miR-760 inhibitor up-regulated its level in SGC-7901 cells. MiR-760-regulated cell properties through reduction of BST2. In addition, miR-760 inhibited tumourigenesis in a nude mouse xenograft model in vivo. In conclusion, our results demonstrated that miR-760 exhibited a suppressive role in gastric cancer via inhibiting BST2, indicating that miR-760/BST2 axis may provide promising therapeutic target for gastric cancer.

Androgen downregulation of miR-760 promotes prostate cancer cell growth by regulating IL6

Prostate cancer (PCa) is one of the most common malignancies in Western countries. Studies have shown that androgen contributes to the progression of PCa, but how androgen promotes PCa remains largely unknown. Here, we demonstrated that androgen suppressed the expression of miR-760 depending on the interaction between androgen and androgen receptor (AR). miR-760 was downregulated in prostate cancer tissues compared with normal tissues. Functional experiments showed that miR-760 downregulation promoted the proliferation and growth of LNCaP and 22rv1 cells. In contrast, miR-760 ectopic expression inhibited the proliferation of LNCaP and 22rv1 cells. DNA synthesis was suppressed by miR-760. Mechanistically, miR-760 bound to the 3'UTR of interleukin 6 (IL6). A mutation in the binding site disrupted their interaction. In addition, silencing of IL6 suppressed the proliferation of LNCaP and 22rv1 cells. IL6 was upregulated in PCa tissues. Our study reveals that androgen downregulates miR-760 to promote the growth of PCa cells by regulating IL6.

The oncogenic potential of NANOG: An important cancer induction mediator

Cancer stem cells (CSCs) are a unique population in the tumor, but they only comprise 2%-5% of the tumor bulk. Although CSCs share several features with embryonic stem cells, CSCs can give rise to the tumor cells. CSCs overexpress embryonic transcription factor NANOG, which is downregulated in differentiated tissues. This transcription factor confers CSC's stemness, unlimited self-renewal, metastasis, invasiveness, angiogenesis, and drug-resistance with the assistance of WNT, OCT4, SOX2, Hedgehog, BMI-1, and other complexes. NANOG facilitates CSCs development via multiple pathways, like angiogenesis and lessening E-cadherin expression levels, which paves the road for metastasis. Moreover, NANOG represses apoptosis and leads to drug-resistance. This review aims to highlight the pivotal role of NANOG and the pertained pathways in CSCs. Also, this current study intends to demonstrate that targeting NANOG can dimmish the CSCs, sensitize the tumor to chemotherapy, and eradicate the cancer cells.

The Role of Breast Cancer Stem Cell-Related Biomarkers as Prognostic Factors

Breast cancer is one of the leading causes of cancer-related deaths in women worldwide, and its incidence is on the rise. A small fraction of cancer stem cells was identified within the tumour bulk, which are regarded as cancer-initiating cells, possess self-renewal and propagation potential, and a key driver for tumour heterogeneity and disease progression. Cancer heterogeneity reduces the overall efficacy of chemotherapy and contributes to treatment failure and relapse. The cell-surface and subcellular biomarkers related to breast cancer stem cell (BCSC) phenotypes are increasingly being recognised. These biomarkers are useful for the isolation of BCSCs and can serve as potential therapeutic targets and prognostic tools to monitor treatment responses. Recently, the role of noncoding microRNAs (miRNAs) has extensively been explored as novel biomarker molecules for breast cancer diagnosis and prognosis with high specificity and sensitivity. An in-depth understanding of the biological roles of miRNA in breast carcinogenesis provides insights into the pathways of cancer development and its utility for disease prognostication. This review gives an overview of stem cells, highlights the biomarkers expressed in BCSCs and describes their potential role as prognostic indicators.

Signaling pathways and microRNAs, the orchestrators of NANOG activity during cancer induction

Cancer stem cells (CSCs) are a small part of cancer cells inside the tumor that have similar characteristics to normal stem cells. CSCs stimulate tumor initiation and progression in a variety of cancers. Several transcription factors such as NANOG, SOX2, and OCT4 maintain the characteristics of CSCs and their upregulation is seen in many malignancies resulting in increased metastasis, invasion, and recurrence. Among these factors, NANOG plays an important role in regulating the self-renewal and pluripotency of CSCs and the clinical significance of NANOG has been suggested as a marker of CSCs in many cancers. The up and down-regulation of NANOG is associated with several important signaling pathways, including JAK/STAT, Wnt/β-catenin, Notch, TGF-β, Hedgehog, and several microRNAs (miRNAs). In this review, we will investigate the function of NANOG in CSCs and the molecular mechanism of its regulation by signaling pathways and miRNAs. We will also investigate targeting NANOG with different techniques, which is a promising treatment strategy for cancer treatment.

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.

Association of miR-760 with cancer: An overview

MicroRNAs (miRNAs) are small non-coding RNA molecules of around 22 nucleotides in length. They are crucially involved in the post transcriptional regulation and thus play a significant role in the modulation of different diseases. Several studies have suggested that miRNA expression is dysregulated in various cancers through different mechanisms and the dysregulated miRNA in return affects different cancer hallmarks including cell proliferation, cell death suppression, metastasis and angiogenesis. Compilation of the available miRNA data can be a stimulator for proper understanding of the correlation between the miRNA expression and cancer progression. In this review, we have focussed on the role of miR-760 in the progression of different cancer. MicroRNA-760 (miR-760) has been found to be down regulated in various cancers, thus it can be utilized as a possible prognostic marker for cancer detection. Here, we have tried to fill a gap regarding the role of miR-760 in relation to cervical cancer also. Moreover, unravelling the role of miR-760 in different cancers will enlighten the researchers with proper understanding of biology of miR-760 in regulation of different cancers.

MicroRNA-760 acts as a tumor suppressor in gastric cancer development via inhibiting G-protein-coupled receptor kinase interacting protein-1 transcription

BACKGROUND

Gastric cancer (GC) has become a serious threat to people's health. Accumulative evidence reveals that dysregulation of numerous microRNAs (miRNAs) has been found during malignant formation. So far, the role of microRNA-760 (miR-760) in the development of GC is largely unknown.

AIM

To measure the expression level of miR-760 in GC and investigate its role in gastric tumorigenesis.

METHODS

Real-time quantitative polymerase chain reaction and Western blot analysis were used to measure the expression of miR-760 and G-protein-coupled receptor kinase interacting protein-1 (GIT1). Cell growth was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and cell colony formation assays. Apoptosis was assessed by flow cytometric analysis. The relationship between miR-760 and GIT1 was verified by luciferase reporter assay.

RESULTS

The results showed that the expression of miR-760 was decreased in GC and associated with poor clinical outcomes in GC patients. Furthermore, miR-760 restrained cell proliferation and cell colony formation and induced apoptosis in GC cells. In addition, miR-760 directly targeted GIT1 and negatively regulated its expression in GC. GIT1 was upregulated in GC and predicted a worse prognosis in GC patients. We also found that upregulation of GIT1 weakened the inhibitory effect of miR-760 in GC.

CONCLUSION

In conclusion, miR-760 targets GIT1 to inhibit cell growth and promote apoptosis in GC cells. Our data demonstrate that miR-760 may be a potential target for the treatment of GC.

LncRNA KCNQ1OT1 enhanced the methotrexate resistance of colorectal cancer cells by regulating miR-760/PPP1R1B via the cAMP signalling pathway

We aimed to explore the mechanism of the KCNQ1OT1/miR‐760/PPP1R1B axis acting to regulate methotrexate (MTX) resistance of colorectal cancer (CRC). Differentially expressed mRNAs and lncRNAs in MTX‐sensitive CRC cell lines and MTX‐resistant cell lines were determined through microarray analysis. Application of bioinformatics analysis was aimed to uncover the relationships among the lncRNAs/miRNAs/mRNAs, and to demonstrate the effects of cAMP signalling pathway in MTX‐resistant CRC. The expression level of RNA and proteins was, respectively, detected using qRT‐PCR and Western blot assays, whereas the dual‐luciferase reporter gene assay was implemented to verify the targeted relationship. The influence of the lncRNA/miRNA/mRNA axis on biological functions of MTX‐resistant cells and on the growth of tumours determined through both vitro and vivo experiments. LncRNA KCNQ1OT1 and PPP1R1B mRNA were overexpressed in MTX‐resistant CRC tumour cells. KCNQ1OT1 functioned as a sponge of miR‐760, which targeted PPP1R1B. Knockdown of KCNQ1OT1 enhanced chemosensitivity towards MTX through the sponging of miR‐760. MiR‐760 expressed at low levels targeted PPP1R1B in the activated cAMP signalling pathway under MTX treatment. Knockdown of KCNQ1OT1 dampened the proliferation of MTX‐resistant (HT29/MTX) cells by regulating the miR‐760/PPP1R1B axis, which also induced cell cycle arrest together with apoptosis. KCNQ1OT1 regulated the expression of PPP1R1B and the downstream genes CREB and CBP in the cAMP signalling pathway. MTX showed a suppressive function on CRC progression. KCNQ1OT1 enhanced the MTX resistance of CRC cells by regulating miR‐760‐mediated PPP1R1B expression via the cAMP signalling pathway.

Long non-coding RNA LOC730100 enhances proliferation and invasion of glioma cells through competitively sponging miR-760 from FOXA1 mRNA

Glioma is the most malignant cancer in central nervous system. And researchers have indicated that long noncoding RNAs (lncRNAs) are closely related with glioma progression. Nevertheless, LOC730100 function in glioma is ill studied. In the current research, we showed that LOC730100 expression was increased in glioma tissues and cell lines. Furthermore, LOC730100 upregulation is linked to a poor prognosis in glioma patients. Loss-of-function assays showed that LOC730100 knockdown inhibited proliferation, migration and invasion of glioma cells, but increasing apoptosis. Notably, we found that LOC730100 was mainly localized in the cytoplasm of glioma cells. We demonstrated that LOC730100 was a competing endogenous RNA (ceRNA) for miR-760 and promoted the expression of FOXA1. We proved that miR-760 suppresses glioma progression and FOXA1 overexpression reversed it. In conclusion, our findings revealed that LOC730100 promoted glioma progression through regulating miR-760/FOXA1 axis.

MicroRNAs and breast cancer stem cells: Potential role in breast cancer therapy

MicroRNAs (miRNAs) can control cancer and cancer stem cells (CSCs), and this topic has drawn immense attention recently. Stem cells are a tiny population of a bulk of tumor cells that have enormous potential in expansion and metastasis of the tumor. miRNA have a crucial role in the management of the function of stem cells. This role is to either promote or suppress the tumor. In this review, we investigated the function and different characteristics of CSCs and function of the miRNAs that are related to them. We also demonstrated the role and efficacy of these miRNAs in breast cancer and breast cancer stem cells (BCSC). Eventually, we revealed the metastasis, tumor formation, and their role in the apoptosis process. Also, the therapeutic potential of miRNA as an effective method for the treatment of BCSC was described. Extensive research is required to investigate the employment or suppression of these miRNAs for therapeutics approached in different cancers in the future.

Prognostic role of miR-760 in hepatocellular carcinoma

Previous studies have demonstrated that microRNA (miR)-760 serves an important role in various cancer types. However, to the best of our knowledge, its role in hepatocellular carcinoma (HCC) has not been fully elucidated. The current study investigated the prognostic role of miR-760 in HCC by using the Kaplan-Meier plotter database. The current data indicated that low expression of miR-760 was associated with higher overall survival (OS) for all patients with HCC from both the RNA-seq [hazard ratio (HR)=2.04; 95% confidence interval (CI)=1.44–2.89; P=4.9×10⁻⁵] and the non-commercial spotted microarray (HR=1.71; CI=1.05–2.76; P=0.028). In the RNA-seq platform, a lower expression of miR-760 was strongly associated with improved OS in male patients with HCC, but not in female patients with HCC. Additionally, low expression of miR-760 was associated with improved OS in patients with stage I, II and III HCC, and was associated with improved OS in Asian and Caucasian patients. The current results indicated that miR-760 serves as an oncogene for HCC and high expression of miR-760 is significantly associated with tumor progression and poor prognosis in patients with HCC.

Long noncoding RNA SNHG6 promotes the progression of colorectal cancer through sponging miR-760 and activation of FOXC1

Background

Colorectal cancer (CRC) is one of most common cancers worldwide. Long non-coding RNA SNHG6 has been reported to act as essential regulators in several cancers. However, the functional role and molecular mechanism of SNHG6 in colorectal cancer remain unclear.

Methods

Quantitative real-time polymerase chain reaction (PCR) was performed to evaluate the SNHG6 expression in CRC tissues. Colony formation, transwell assays and in vivo mice models were carried out to assess the effect of SNHG6 on CRC biological functions.

Results

In the present study, we showed that the expression of SNHG6 was significantly upregulated in CRC tissues and cell lines. High expression of SNHG6 was associated with shorter overall survival in CRC patients. Functionally, SNHG6 knockdown significantly inhibited cell proliferation, invasion and migration both in vitro and in vivo. Mechanically, miR-760 was a direct target of SNHG6, and repression of miR-760 could rescue the inhibitory effect of SNHG6 knockdown on CRC progression. In addition, SNHG6 positively regulated FOXC1 expression through sponging miR-760 in CRC cells, thus indicating that SNHG6 exerted an oncogenic role in CRC by acting as a ceRNA of miR-760.

Conclusion

Our results indicate that long non-coding RNA SNHG6 promotes colorectal cancer progression by sequestering miR-760 and activating FOXC1, our findings suggest that SNHG6 may serve as a potential therapeutic target for CRC.

MicroRNA-760 Inhibits Doxorubicin Resistance in Hepatocellular Carcinoma through Regulating Notch1/Hes1-PTEN/Akt Signaling Pathway

Accumulating studies have suggested that microRNA-760 (miR-760) plays an important role in chemoresistance of various cancer cells. However, whether miR-760 regulates the chemoresistance of hepatocellular carcinoma (HCC) remains unclear. In this study, we found that miR-760 was decreased in HCC cell lines, and doxorubicin (Dox) treatment significantly decreased miR-760 expression in HCC cells. Overexpression of miR-760 sensitized HCC cells to Dox-induced cytotoxicity and apoptosis, whereas miR-760 inhibition showed the opposite effects. Notch1 was predicted as a target gene of miR-760. miR-760 negatively regulated Notch1 expression and Notch1/Hes1 signaling. Overexpression of miR-760 increased PTEN expression and decreased the phosphorylation of Akt. Activation of Notch signaling significantly reversed the inhibitory effect of miR-760 on Dox-resistance and abrogated the effect of miR-760 on the PTEN/Akt signaling pathway in HCC cells. Overall, our results demonstrate that miR-760 inhibits Dox-resistance in HCC cells through inhibiting Notch1 and promoting PTEN expression.

MiR-760 suppresses non-small cell lung cancer proliferation and metastasis by targeting ROS1

MicroRNAs (miRNAs) have been shown to be critical regulators in many types of tumors. The aim of our study was to investigate the role of miR-760 in non-small cell lung cancer (NSCLC). We demonstrated that the expression of miR-760 was downregulated in NSCLC tissues compared with the adjacent normal tissues. We also demonstrated that the expression of miR-760 was downregulated in the NSCLC cell lines. Overexpression of miR-760 suppressed the NSCLC cell proliferation, cell cycle, and migration. Moreover, we identified that ROS1 was a direct target of miR-760 in the NSCLC cell. Elevated expression of miR-760 suppressed ROS1 expression in the NSCLC cell. We also demonstrated that the expression of ROS1 was higher in the NSCLC tissues than in the adjacent lung tissues. MiR-760 expression level was reversely associated with the expression level of ROS1 in the NSCLC tissues. In summary, we showed that miR-760 suppressed the NSCLC cell proliferation, cell cycle, and migration through regulating the ROS1 expression. These data suggested that miR-760 may act as a tumor suppressor gene in the NSCLC partly through regulating ROS1 expression.

MiR-760 suppresses human colorectal cancer growth by targeting BATF3/AP-1/cyclinD1 signaling

Background

Recent studies have reported that microRNAs (miRNAs) often function as negative post-transcriptional regulators with altered expression levels found in colorectal cancer (CRC). There have been few studies on miRNAs that regulate the oncogenic alterations in CRC. Here, we aim to explore the anti-cancer miRNA and the potential mechanisms by which miRNAs modulate CRC progression.

Methods

We performed an integrated analysis of CRC miRNA expression datasets in The Cancer Genome Atlas (TCGA). The miRNA with the lowest expression, miR-760, was validated in an independent validation sample cohort of 76 CRC tissues. Functional assays, such as CCK-8 assay, colony formation assay, and CFSE staining, were used to determine the oncogenic role of miR-760 in human CRC progression. Furthermore, western blotting and dual-luciferase reporter assay were used to determine the mechanism by which miR-760 promotes proliferation of CRC cells. Xenograft nude mouse models were used to determine the role of miR-760 in CRC tumorigenicity in vivo. Immunohistochemical assays were conducted to study the relationship between miR-760 expression and basic leucine zipper transcriptional factor ATF-like 3 (BATF3) expression in human CRC samples.

Results

miR-760 was markedly downregulated in CRC tissues, and low miR-760 expression was associated with poor prognosis among CRC patients. Upregulation of miR-760 suppressed CRC cell proliferation, whereas downregulation of miR-760 promoted CRC proliferation in vitro. Additionally, we identified BATF3 as a direct target of miR-760, and that the essential biological function of miR-760 during CRC progression both in vitro and in vivo is to suppress the expression of BATF3 and downstream cyclinD1 via AP-1 transcription factor. Finally, we showed a significant correlation between miR-760 and BATF3 expression in CRC tissues.

Conclusions

miR-760 inhibited CRC growth by downregulating BATF3/AP-1/ cyclinD1 signaling.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0757-8) contains supplementary material, which is available to authorized users.

MiR-760 enhances TRAIL sensitivity in non-small cell lung cancer via targeting the protein FOXA1

Non-small cell lung cancer (NSCLC) is one of the leading cause of death worldwide. TNF-related apoptosis-inducing ligand (TRAIL) is a promising anti-tumor agent with the ability to kill tumor cells while spare normal ones. MicroRNAs (miRNAs) are small, non-coding RNAs that play vital roles in carcinogenesis. Although miR-760 has been reported to be dysregulated in a variety of cancers, the role of miR-760 in NSCLC is not fully understood, and the relationship between miR-760 dysregulation and TRAIL sensitivity is still elusive. In the current study, we found that miR-760 is significantly downregulated in NSCLC tissues and cell lines. We also found that ectopic expression of miR-760, by targeting the FOXA1, enhanced TRAIL sensitivity in NSCLC cells. Correspondingly, silencing of FOXA1 also sensitized NSCLC cell to TRAIL-induced apoptosis and proliferation inhibition. In summary, these findings suggest that miR-760 should be considered as a tumor suppressor since it negatively regulates the oncogene protein FOXA1 and regulated TRAIL sensitivity in NSCLC cells.

MicroRNA‑760 inhibits cell proliferation and invasion of colorectal cancer by targeting the SP1‑mediated PTEN/AKT signalling pathway

Colorectal cancer (CRC), one of the most commonly diagnosed types of cancer worldwide, is the third most prevalent and fourth most frequent cause of cancer‑related mortality. Dysregulated microRNAs (miRNAs) have potential regulatory roles in the development and progression of various cancer types. Therefore, the investigation of the miRNAs involved in CRC formation and progression may lead to the development of highly effective therapeutic strategies for CRC. In the present study, miRNA‑760 (miR‑760) was frequently downregulated in CRC tissues and cell lines. The low levels of miR‑760 expression were significantly correlated with the tumor size, lymph node metastasis and TNM stage of CRC. Functional assays revealed that restoring miR‑760 expression inhibited CRC cell proliferation and invasion in vitro. The results of bioinformatics analysis, luciferase reporter assay, reverse transcription‑quantitative polymerase chain reaction and western blot analysis suggested that specificity protein 1 (SP1) is a direct target of miR‑760 in CRC. The high expression of SP1 in CRC tissues was inversely correlated with the expression of miR‑760. Rescue experiments demonstrated that enforced SP1 expression rescued the tumor‑suppressing effects of miR‑760 on CRC cell proliferation and invasion. In addition, miR‑760 overexpression is involved in the regulation of the PTEN/AKT signalling pathway. Collectively, the present data demonstrated that miR‑760 directly targets SP1 to inactivate the PTEN/AKT signalling pathway, thus implicating miR‑760 in the regulation of CRC cell proliferation and invasion. Therefore, miR‑760 may be a novel biomarker and therapeutic target for CRC.

Mechanisms of aortic dissection smooth muscle cell phenotype switch

OBJECTIVE

To investigate the expression of Nanog homeobox (NANOG) in thoracic aortic dissection (TAD) and the role of NANOG in regulating human aortic vascular smooth muscle cells (VSMCs) phenotype switch.

METHODS

Aortic specimens were collected from 20 patients undergoing TAD and 10 controls. VSMCs were isolated by adherent cultivation approach. The expression of NANOG, osteopontin (OPN), and VSMCs phenotype markers were determined by quantitative real-time polymerase chain reaction, Western blot, immunohistochemistry, and immunofluorescence. Cell counting, scratch wound-healing assay, Transwell migration, and apoptosis assays were used for cell function assessment. Deoxyribonucleic acid-protein binding detection was performed by chromatin immunoprecipitation.

RESULTS

Our experiment results showed that NANOG and OPN were highly expressed in TAD aortic wall and VSMCs, both accompanying VSMCs phenotype switch. Overexpression of NANOG induced the up-regulation of VSMCs synthetic marker matrix metalloproteinase 2 and the down-regulation of VSMCs contractile markers α-smooth muscle actin and smooth muscle 22α. Overexpression of NANOG also enhanced the proliferation, migration, and antiapoptosis capabilities of VSMCs. The results also showed that these functions of NANOG was via OPN and NANOG directly up-regulated OPN by binding to its promoter region.

CONCLUSIONS

Our study suggests that NANOG is highly expressed in TAD aortic wall and VSMCs. Increased NANOG promotes VSMCs phenotype switch by directly up-regulating OPN through binding to its promoter region.