By downregulating Ku80, hsa-miR-526b suppresses non-small cell lung cancer

Exosome miR-101-3p derived from bone marrow mesenchymal stem cells promotes radiotherapy sensitivity in non-small cell lung cancer by regulating DNA damage repair and autophagy levels through EZH2

BACKGROUND AND OBJECTIVE

The morbidity rate of non-small cell lung cancer (NSCLC) increases with age, highlighting that NSCLC is a serious threat to human health. The aim of this study was mainly to describe the role of exosomal miR-101-3p derived from bone marrow mesenchymal stem cells (BMSCs) in NSCLC.

METHODS

A549 or NCI-H1703 cells (1×105/mouse) were injected into nude mice to establish an NSCLC animal model. RTqPCR, Western blotting and comet assays were used to assess the changes in gene expression, proteins and DNA damage repair.

RESULTS

miR-101-3p and RAI2 were found to be expressed at low levels in NSCLC, while EZH2 was highly expressed. In terms of function, miR-101-3p downregulated EZH2. In addition, exosomal miR-101-3p derived from BMSCs promoted the expression of RAI2, inhibited DNA damage repair, and inhibited the activation of the PI3K/AKT/mTOR signaling pathway by inhibiting EZH2, thereby promoting autophagy and decreasing cell viability and finally enhancing the sensitivity of NSCLC to radiotherapy and inhibiting the malignant biological behavior of NSCLC.

CONCLUSION

Exosomal miR-101-3p derived from BMSCs can inhibit DNA damage repair, promote autophagy, enhance the radiosensitivity of NSCLC, and inhibit the progression of NSCLC by inhibiting EZH2.

The role of HIF-1α-mediated autophagy in ionizing radiation-induced testicular injury

Testis, as a key organ for maintaining male fertility, are extremely sensitive to ionizing radiation (IR). IR-induced testicular dysfunction and infertility are common adverse effects of radiation therapy in patients with pelvic cancer. To study the phenotype and mechanism of IR-induced testicular injury, the mice were irradiated with different radiation doses (0, 2 and 5 Gy) below the semi-lethal dose for one month. Our present results showed that testicular weight and the serum testosterone levels significantly decreased with the structural injury of the testis in an IR dose-dependent manner, indicating that IR caused not only the structural damage of the testis, but also the functional damage. Further analysis by TUNEL staining and Western blotting found that IR induced the apoptosis in a dose-dependent manner as indicated by increased expressions of cleaved caspase3, p53 and Bax on Day 15 after IR treatment. Combined with significantly increased oxidative stress, these results indicated that IR-induced testicular damage may be a long-term, progressively aggravated process, accompanied by apoptosis. Given the role of autophagy in apoptosis, the present study also detected and analyzed the localization and expressions of autophagy-related proteins LC-3I/II, beclin1, p62 and Atg12 in testicular cells, and found that LC-3II, beclin1 and Atg12 expressions significantly increased in the testicular cells of mice irradiated with 2 Gy and 5 Gy, while p62 expression significantly decreased with 5 Gy, implying autophagy was involved in the apoptosis of testicular cells induced by IR. Furthermore, the expressions of HIF-1α and BNIP3 were significantly enhanced in the testis cells of mice irradiated with 2 Gy and 5 Gy, suggesting the potential role of HIF-1α/BNIP3-mediated autophagy in the apoptosis of testicular cells induced by IR. Taken together, our findings demonstrated that HIF-1α/BNIP3-mediated autophagy not only plays a protective effect on the testicular cells of mice irradiated with 2 Gy, but also induces the apoptosis of the testicular cells of mice irradiated with 5 Gy, indicating the double effects on apoptosis, which will help us further understanding the molecular mechanisms of IR-induced testicular injury, and will facilitate us further studies on testicular radioprotection.

miR-526b-5p/c-Myc/Foxp1 participates in recurrent spontaneous abortion by regulating the proliferation, migration, and invasion of trophoblasts

PURPOSE

As a member of the C19MC family, miR-526b-5p is mainly expressed in the placental tissue and is a well-known tumor suppressor microRNA. However, its effect on the function of trophoblasts and its role in the development of recurrent spontaneous abortion (RSA) remains unclear.

METHODS

Transcriptome sequencing, quantitative real-time polymerase chain reaction (RT-qPCR), Western blot, 5-ethynyl-2'-deoxyuridine (Edu) proliferation analysis, cell counting kit-8 (CCK8) assay, Transwell assays, and wound healing were used to detect the proliferation, migration, and invasion capacity of trophoblasts. Target genes of miR-526b-5p were obtained by the dual luciferase reporter system. The promoter-reporter system and ChIP-qPCR were used to prove that c-Myc positively regulated the expression of Foxp1 RESULTS: The miR-526b-5p levels were significantly higher in patients with RSA than in controls. High expression of miR-526b-5p inhibited the proliferation, migration, and invasion of trophoblast cell line. By contrast, low expression of miR-526b-5p promoted the proliferation and migration of trophoblast cell line. Target genes of miR-526b-5p were c-Myc and Foxp1. c-Myc positively regulated the expression of Foxp1 by binding to the Foxp1 promoter location -146/-135. Finally, miR-526b-5p impeded the proliferation, migration, and invasion of trophoblasts by negatively regulating c-Myc by rescue experiments.

CONCLUSION

Thus, miR-526b-5p affected the proliferation, migration, and invasion of trophoblasts by targeting c-Myc and Foxp1. Low expression of c-Myc further deactivated the positive transcriptional regulation of c-Myc on Foxp1, which may be the mechanism of RSA. This study provides potential therapeutic targets and clues for the diagnosis and treatment of RSA.

Silencing CircEIF3I/miR-526b-5p Axis Epigenetically Targets HGF/c-Met Signal to Hinder the Malignant Growth, Metastasis and Angiogenesis of Hepatocellular Carcinoma

BACKGROUND

Hepatocyte growth factor (HGF)/c-mesenchymal-epithelial transition factor (c-Met) is important for the diagnosis and prognosis of hepatocellular carcinoma (HCC). Circular RNAs (circRNAs) are key regulators of HCC progression, and this study focused on circRNA eukaryotic translation initiation factor 3 subunit I (circEIF3I) with HGF/c-Met in HCC.

METHODS

Levels of circEIF3I, microRNA (miR)-526b-5p, HGF, E-cadherin, N-cadherin, and Vimentin were detected by Gene Expression Omnibus database, quantitative PCR and western blotting. Cell functions were measured by detecting cell growth (cell proliferation assay with WST-1 and EdU, colony formation assay, flow cytometry, caspase 3 activity assay, and nude mouse tumorigenicity assay), metastasis (transwell assay and western blotting), angiogenesis (endothelial tube formation assay). Molecular interaction was determined dual-luciferase reporter assay, RNA immunoprecipitation, and Pearson correlation analysis.

RESULTS

Expression of circEIF3I was upregulated in HCC tissues. Knockdown of circEIF3I suppressed cell proliferation epithelial-mesenchymal transition, migration, invasion and tube formation ability but promoted apoptosis of HCC cells. CircEIF3I could sponge miR-526b-5pto regulate downstream HGF. Functionally, circEIF3I regulation in HCC cell progression was associated with miR-526b-5p sponging function and HGF upregulation could attenuate tumor-inhibiting roles of miR-526b-5p. HCC tumor growth was delayed by interfering circEIF3I.

CONCLUSION

CircEIF3I was an oncogenic circRNA in HCC-, and interfering circEIF3I exhibited anti-HCC activity via circEIF3I-miR-526b-5p-HGF/c-Met pathway.

DNA Damage Response in Cancer Therapy and Resistance: Challenges and Opportunities

Resistance to chemo- and radiotherapy is a common event among cancer patients and a reason why new cancer therapies and therapeutic strategies need to be in continuous investigation and development. DNA damage response (DDR) comprises several pathways that eliminate DNA damage to maintain genomic stability and integrity, but different types of cancers are associated with DDR machinery defects. Many improvements have been made in recent years, providing several drugs and therapeutic strategies for cancer patients, including those targeting the DDR pathways. Currently, poly (ADP-ribose) polymerase inhibitors (PARP inhibitors) are the DDR inhibitors (DDRi) approved for several cancers, including breast, ovarian, pancreatic, and prostate cancer. However, PARPi resistance is a growing issue in clinical settings that increases disease relapse and aggravate patients' prognosis. Additionally, resistance to other DDRi is also being found and investigated. The resistance mechanisms to DDRi include reversion mutations, epigenetic modification, stabilization of the replication fork, and increased drug efflux. This review highlights the DDR pathways in cancer therapy, its role in the resistance to conventional treatments, and its exploitation for anticancer treatment. Biomarkers of treatment response, combination strategies with other anticancer agents, resistance mechanisms, and liabilities of treatment with DDR inhibitors are also discussed.

Interactions between miRNAs and Double-Strand Breaks DNA Repair Genes, Pursuing a Fine-Tuning of Repair

The repair of DNA damage is a crucial process for the correct maintenance of genetic information, thus, allowing the proper functioning of cells. Among the different types of lesions occurring in DNA, double-strand breaks (DSBs) are considered the most harmful type of lesion, which can result in significant loss of genetic information, leading to diseases, such as cancer. DSB repair occurs through two main mechanisms, called non-homologous end joining (NHEJ) and homologous recombination repair (HRR). There is evidence showing that miRNAs play an important role in the regulation of genes acting in NHEJ and HRR mechanisms, either through direct complementary binding to mRNA targets, thus, repressing translation, or by targeting other genes involved in the transcription and activity of DSB repair genes. Therefore, alteration of miRNA expression has an impact on the ability of cells to repair DSBs, which, in turn, affects cancer therapy sensitivity. This latter gives account of the importance of miRNAs as regulators of NHEJ and HRR and places them as a promising target to improve cancer therapy. Here, we review recent reports demonstrating an association between miRNAs and genes involved in NHEJ and HRR. We employed the Web of Science search query TS (“gene official symbol/gene aliases*” AND “miRNA/microRNA/miR-”) and focused on articles published in the last decade, between 2010 and 2021. We also performed a data analysis to represent miRNA–mRNA validated interactions from TarBase v.8, in order to offer an updated overview about the role of miRNAs as regulators of DSB repair.

MicroRNAs and the DNA damage response: How is cell fate determined?

It is becoming clear that the DNA damage response orchestrates an appropriate response to a given level of DNA damage, whether that is cell cycle arrest and repair, senescence or apoptosis. It is plausible that the alternative regulation of the DNA damage response (DDR) plays a role in deciding cell fate following damage. MicroRNAs (miRNAs) are associated with the transcriptional regulation of many cellular processes. They have diverse functions, affecting, presumably, all aspects of cell biology. Many have been shown to be DNA damage inducible and it is conceivable that miRNA species play a role in deciding cell fate following DNA damage by regulating the expression and activation of key DDR proteins. From a clinical perspective, miRNAs are attractive targets to improve cancer patient outcomes to DNA-damaging chemotherapy. However, cancer tissue is known to be, or to become, well adapted to DNA damage as a means of inducing chemoresistance. This frequently results from an altered DDR, possibly owing to miRNA dysregulation. Though many studies provide an overview of miRNAs that are dysregulated within cancerous tissues, a tangible, functional association is often lacking. While miRNAs are well-documented in 'ectopic biology', the physiological significance of endogenous miRNAs in the context of the DDR requires clarification. This review discusses miRNAs of biological relevance and their role in DNA damage response by potentially 'fine-tuning' the DDR towards a particular cell fate in response to DNA damage. MiRNAs are thus potential therapeutic targets/strategies to limit chemoresistance, or improve chemotherapeutic efficacy.

Circ_0001821 knockdown suppresses growth, metastasis, and TAX resistance of non-small-cell lung cancer cells by regulating the miR-526b-5p/GRK5 axis

Non-small-cell lung cancer (NSCLC) remains a huge obstacle to human health. Certain circular RNAs endow with crucial regulatory roles in NSCLC progression. Here, we investigated the functional effects of circ_0001821 on cellular behaviors of NSCLC cells and explored the possible mechanism. The expression of circ_0001821, microRNA (miR)-526b-5p, and G protein-coupled receptor kinase 5 (GRK5) was determined by quantitative real-time polymerase chain reaction or Western blot assay. Clonogenicity in NSCLC cells was detected via colony formation assay. Cell migration and invasion were monitored by Transwell assay. Cell sensitivity to paclitaxel (TAX) evaluated by Cell Counting Kit-8 assay. Cell apoptosis was assessed by flow cytometry, caspase-3 activity, and caspase-9 activity. The targeted relationship between miR-526b-5p and circ_0001821 or GRK5 was confirmed by dual-luciferase reporter or RNA pull-down assay. Moreover, the role of circ_0001821 in vivo was examined by xenograft model assay. The results presented that the expression of circ_0001821 and GRK5 was increased, while miR-526b-5p expression was decreased in NSCLC tissues and cells. Circ_0001821 knockdown reduced colony formation ability and metastasis ability but enhanced TAX sensibility and apoptosis of NSCLC cells, which was attenuated by miR-526b-5p inhibition or GRK5 overexpression. Circ_0001821 targeted miR-526b-5p, and miR-526b-5p targeted GRK5. Circ_0001821 could upregulate GRK5 expression by sponging miR-526b-5p. Depletion of circ_0001821 also blocked tumor growth in vivo. In conclusion, the depletion of circ_0001821 inhibited NSCLC progression, at least in part, by modulating the miR-526b-5p/GRK5 axis.

The Role of RNA in DNA Breaks, Repair and Chromosomal Rearrangements

Incorrect reparation of DNA double-strand breaks (DSB) leading to chromosomal rearrangements is one of oncogenesis's primary causes. Recently published data elucidate the key role of various types of RNA in DSB formation, recognition and repair. With growing interest in RNA biology, increasing RNAs are classified as crucial at the different stages of the main pathways of DSB repair in eukaryotic cells: nonhomologous end joining (NHEJ) and homology-directed repair (HDR). Gene mutations or variation in expression levels of such RNAs can lead to local DNA repair defects, increasing the chromosome aberration frequency. Moreover, it was demonstrated that some RNAs could stimulate long-range chromosomal rearrangements. In this review, we discuss recent evidence demonstrating the role of various RNAs in DSB formation and repair. We also consider how RNA may mediate certain chromosomal rearrangements in a sequence-specific manner.

Role of microRNAs in Lung Carcinogenesis Induced by Asbestos

MicroRNAs are a class of small noncoding endogenous RNAs 19–25 nucleotides long, which play an important role in the post-transcriptional regulation of gene expression by targeting mRNA targets with subsequent repression of translation. MicroRNAs are involved in the pathogenesis of numerous diseases, including cancer. Lung cancer is the leading cause of cancer death in the world. Lung cancer is usually associated with tobacco smoking. However, about 25% of lung cancer cases occur in people who have never smoked. According to the International Agency for Research on Cancer, asbestos has been classified as one of the cancerogenic factors for lung cancer. The mechanism of malignant transformation under the influence of asbestos is associated with the genotoxic effect of reactive oxygen species, which initiate the processes of DNA damage in the cell. However, epigenetic mechanisms such as changes in the microRNA expression profile may also be implicated in the pathogenesis of asbestos-induced lung cancer. Numerous studies have shown that microRNAs can serve as a biomarker of the effects of various adverse environmental factors on the human body. This review examines the role of microRNAs, the expression profile of which changes upon exposure to asbestos, in key processes of carcinogenesis, such as proliferation, cell survival, metastasis, neo-angiogenesis, and immune response avoidance.

A circGLIS3/miR-644a/PTBP1 positive feedback loop promotes the malignant biological progressions of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a severe cancer which critically threatens human health in the world. Circular RNAs (circRNAs) are non-coding RNAs that involve in cancer progression. We want to explore the roles of circRNAs in NSCLC in this study. In current study, circGLIS3 was found to be highly expressed in NSCLC tissues and cell lines and high circGLIS3 level was correlated to malignant characteristics and poor prognosis of NSCLC. Functional experiments suggested that circGLIS3 promoted proliferation, migration and invasion and arrested apoptosis of NSCLC cells in vitro. CircGLIS3 also participated in the in vivo process by accelerate NSCLC tumor growth and metastasis. Mechanistically, circGLIS3 could sponging multiple anti-cancer miRNAs including miR-526b, miR-198, miR-498 and miR-664a. Here, we for the first time confirmed that miR-644a was downregulated and functioned as a tumor suppression gene in NSCLC. In addition, we found PTBP1 as a novel target of miR-644a and circGLIS3 could raise the expression of PTBP1 via miR-644a. And PTBP1 could bind to the flanking introns of circGLIS3 and thereby promoting looping of circGLIS3. In conclusion, CircGLIS3 functions as an oncogene via sponging multiple tumor-suppressive miRNAs in NSCLC. A circGLIS3/miR-644a/PTBP1 positive feedback loop exists in the tumorigenesis and development of NSCLC.

Jack of all trades? The versatility of RNA in DNA double-strand break repair

The mechanisms by which RNA acts in the DNA damage response (DDR), specifically in the repair of DNA double-strand breaks (DSBs), are emerging as multifaceted and complex. Different RNA species, including but not limited to; microRNA (miRNA), long non-coding RNA (lncRNA), RNA:DNA hybrid structures, the recently identified damage-induced lncRNA (dilncRNA), damage-responsive transcripts (DARTs), and DNA damage-dependent small RNAs (DDRNAs), have been shown to play integral roles in the DSB response. The diverse properties of these RNAs, such as sequence, structure, and binding partners, enable them to fulfil a variety of functions in different cellular contexts. Additionally, RNA can be modified post-transcriptionally, a process which is regulated in response to cellular stressors such as DNA damage. Many of these mechanisms are not yet understood and the literature contradictory, reflecting the complexity and expansive nature of the roles of RNA in the DDR. However, it is clear that RNA is pivotal in ensuring the maintenance of genome integrity. In this review, we will discuss and summarise recent evidence which highlights the roles of these various RNAs in preserving genomic integrity, with a particular focus on the emerging role of RNA in the DSB repair response.

miR-623 suppresses cell proliferation, migration and invasion through direct inhibition of XRCC5 in breast cancer

Background/Aims: MicroRNAs (miRNAs) are short, non-coding RNA molecules that control gene expression trough negative translational regulation. MiR-623 is a tumor suppressor, and it’s function and mechanism in breast cancer has not been reported.

Results: Exogenous overexpression of miR-623 suppressed cell proliferation, migration and invasion, meanwhile, but promoted cell apoptosis. MiR-623 knockdown displayed opposite results. Overexpression of miR-623 resulted in the downregulation of CDK4/6 as well as the inhibition of the phosphatidylinositol-3-kinase (PI3K)/Akt and Wnt/β-Catenin signaling pathways. MiR-623 knockdown displayed opposite results. Results of the reporter assay revealed that the luciferase activity was decreased in XRCC5-wt cells, suggesting that miR-623 could directly combine with 3’ UTR of XRCC5. MiR-623 significantly suppressed XRCC5 expression, which is critical for miR-623-induced proliferation and migration block in breast cancer cells.

Conclusion: miR-623 suppressed cell proliferation, migration and invasion through downregulation of cyclin dependent kinases and inhibition of the phosphatidylinositol-3-kinase (PI3K)/Akt and Wnt/β-Catenin pathways by targeting XRCC5.

Methods: miR-623 was either overexpressed in breast cancer cell lines through exogenous transfection or knocked down by specific siRNA. Cell proliferation, migration and invasion were examined using CCK-8, colony formation and transwell assay. The direct target of miR-623 was verified using luciferase reporter gene assay.

A potential prognostic model based on miRNA expression profile in The Cancer Genome Atlas for bladder cancer patients

Background

This study aimed to construct prognostic model by screening prognostic miRNA signature of bladder cancer.

Methods

The miRNA expression profile data of bladder cancer (BC) in The Cancer Genome Atlas (TCGA) were obtained and randomly divided into the training set and the validation set. Differentially expressed miRNAs (DEMs) between BC and normal control samples in the training set were firstly identified, and DEMs related to prognosis were screened by Cox Regression analysis. Then, the MiR Score system was constructed using X-Tile based cutoff points and verified in the validation set. The prognostic clinical factors are selected out by univariate and multivariate Cox Regression analysis. Finally, the mRNAs related to prognosis were screened and the biological pathway analysis was carried out.

Results

We identified the 7-miRNA signature was significantly associated with the patient’s Overall Survival (OS). A prognostic model was constructed based on the prognostic 7-miRNA signature, and possessed a relative satisfying predicted ability both in the training set and validation set. In addition, univariate and multivariate Cox Regression analysis showed that age, lymphovascular invasion and MiR Score were considered as independent prognostic factors in BC patients. Furthermore, based on MiR Score prognostic model, several differentially expressed genes (DEGs), such as WISP3 and UNC5C, as well as their related biological pathway(s), including cell–cell adhesion and neuroactive ligand-receptor interaction, were considered to be related to BC prognosis.

Conclusion

The prognostic model which was constructed based on the prognostic 7-miRNA signature presented a high predictive ability for BC.

The genetic script of metastasis

Metastasis is a pivotal event that changes the course of cancers from benign and treatable to malignant and difficult to treat, resulting in the demise of patients. Understanding the genetic control of metastasis is thus crucial to develop efficient and sustainable targeted therapies. Here we discuss the alterations in epigenetic mechanisms, transcription, chromosomal instability, chromosome imprinting, non-coding RNAs, coding RNAs, mutant RNAs, enhancers, G-quadruplexes, and copy number variation to dissect the genetic control of metastasis. We conclude that the genetic control of metastasis is predominantly executed through epithelial to mesenchymal transition and evasion of cell death. We discuss how genetic regulatory mechanisms can be harnessed for therapeutic purposes to achieve sustainable control over cancer metastasis.

LOC134466 methylation promotes oncogenesis of endometrial carcinoma through LOC134466/hsa-miR-196a-5p/TAC1 axis

To investigate possible mechanism of abnormal methylation of long non-coding RNA (lncRNA) on endometrial carcinoma (EC) progression, we detected the genome methylation profiling of endometrial carcinoma by bioinformatic analysis. Accordingly, gene LOC134466 was chosen for the further research. We also found that TAC1 was the target gene of LOC134466 and miRNA, hsa-miR-196a-5p, might form a connection between LOC134466 and TAC1. The relationship was further proved by dual-luciferase reporter assay. In vitro studies, DNA methylation and expression were determined by MSP and qRT-PCR respectively. Cell proliferation, apoptosis and cell cycle were demonstrated by colony formation assay, Annexin V/PI double staining and flow cytometry. Besides, the function of LOC134466 and TAC1 in EC was further confirmed by Tumor Xenograft. Our results indicated that EC progression was promoted by hypermethylated LOC134466 and TAC1. Moreover, TAC1 transcription was regulated by LOC134466 via hsa-miR-196a-5p binding. LOC134466 and TAC1 demethylation by 5-Aza-2-Deoxycytidine inhibited EC cells proliferation and accelerated cell apoptosis. Furthermore, the expression of TACR1, TACR2 and TACR3 was remarkably decreased through LOC134466 and TAC1 treatments. Our findings establish a novel regulatory axis, LOC134466/hsa-miR-196a-5p/TAC1. Downregulation of the axis promoted EC development through TACR3, which further activated neuroactive ligand-receptor interaction.

lncRNA PVT1 accelerates progression of non-small cell lung cancer via targeting miRNA-526b/EZH2 regulatory loop

Biological function of plasmacytoma variant translocation 1 (PVT1) in influencing the progression of non-small cell lung cancer (NSCLC) through Micro ribonucleic acid (miRNA)-526b/EZH2 regulatory loop was elucidated. Relative levels of PVT1 and miRNA-526b in NSCLC tissues were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Prognostic potential of PVT1 in NSCLC was assessed by Kaplan-Meier curves. The interaction among PVT1/miRNA-526b/EZH2 regulatory loop was confirmed by dual-luciferase reporter gene assay. Regulatory effects of PVT1/miRNA-526b/EZH2 axis on viability and wound closure of A549 cells were evaluated by cell counting kit-8 (CCK-8) and wound closure assay, respectively. PVT1 was upregulated in NSCLC tissues, while miRNA-526b was downregulated. PVT1 level was negatively related to that of miR-526 in NSCLC tissues. Worse survival was seen in NSCLC patients expressing high level of PVT1 compared to those with low level. Knockdown of PVT1 attenuated viability and wound closure ability in A549 cells, which were partially reversed after miRNA-526b knockdown. miRNA-526b is the downstream target of PVT1 and its level was negatively regulated by PVT1. EZH2 is the target gene of miRNA-526b. Transfection of miRNA-526b mimic remarkably downregulated EZH2 in A549 cells. Importantly, the attenuated viability and wound closure ability in A549 cells overexpressing miRNA-526b were reversed after EZH2 overexpression. PVT1 is upregulated in NSCLC, and predicts a poor prognosis. PVT1 accelerates the progression of NSCLC via targeting miRNA-526b/EZH2 regulatory loop.

YY1 promotes colorectal cancer proliferation through the miR-526b-3p/E2F1 axis

We previously reported that E2F1 expression is up-regulated and positively correlated with the malignant phenotypes of colorectal cancer (CRC). However, the underlying mechanisms leading to the aberrant up-regulation of E2F1 in CRC have not been clarified. In this study, we observed that miR-526b-3p directly targets the 3'UTR of E2f1 mRNA, leading to reduced E2F1 expression. Overexpression of miR-526b-3p inhibited the proliferation of CRC cells by decreasing the level of E2F1. We also found that the Ying Yang 1 (YY1)-dependent transcriptional suppression of miR-526b-3p is responsible for the up-regulation of E2F1 in CRC, in which YY1 binds to the promoter of miR-526b gene and recruits histone deacetylase (HDAC). Knockdown of YY1 led to cell cycle arrest and diminished colony formation in CRC cells partly through relieving the miR-526b-3p suppression. Clinical analysis showed that YY1 and E2F1 were negatively correlated with miR-526b-3p in CRC tissues. Moreover, a high level of YY1 and E2F1, or a low level of miR-526b-3p, predicted poor survival of CRC patients. In conclusion, our findings highlight the dysregulation of the YY1/miR-526b-3p/E2F1 axis in CRC development, implicating a novel regulatory pathway for E2F1 as a potential therapeutic target in CRC.

LncRNA LOXL1-AS1 promotes invasion and proliferation of non-small-cell lung cancer through targeting miR-324-3p

LncRNAs are played crucial roles in athogenesis of NSCLC. LOXL1-AS1 involved in development of several tumors. So far, there is no study about expression and function pattern of the LOXL1-AS1 in NSCLC. In this reference, we firstly proved that LOXL1-AS1 was overexpressed in NSCLC cell lines (H23, A549, H1299 and SPC-A1) compared to 16HBE cell. The expression of LOXL1-AS1 was overexpressed in NSCLC specimens than adjacent control specimens. We found that 29 of 40 cases showed higher LOXL1-AS1 expression in NSCLC samples as compared to adjacent control specimens. Ectopic expression of LOXL1-AS1 promoted H1299 cell and H23 cell proliferation. LOXL1-AS1 overexpression promoted ki-67 and cyclin D1 expression in the NSCLC cell. Overexpression of LOXL1-AS1 promoted cell invasion and induced N-cadherin and Vimentin expression and suppressed E-cadherin expression in the NSCLC cell. LOXL1-AS1 acts as one sponge for miR-324-3p in NSCLC cell. Moreover, the expression of miR-324-3p was lower in NSCLC specimens than adjacent control specimens. We found that 24 of 40 cases showed lower miR-324-3p expression in NSCLC samples as compared to adjacent control specimens. Further correlation assay indicated a negative association between miR-324-3p and LOXL1-AS1 expression. miR-324-3p restoration attenuates the function of LOXL1-AS1 overexpression on NSCLC cell. These results indicated that LOXL1-AS1 enhanced NSCLC cell proliferation and invasion via sponging miR-324-3p in NSCLC cell.

Circ_SPECC1 enhances the inhibition of miR-526b on downstream KDM4A/YAP1 pathway to regulate the growth and invasion of gastric cancer cells

Gastric cancer (GC) is a common malignant tumor, and many studies have shown that circular RNAs (circRNAs) play important roles in the progress of GC. This study showed that circ_SPECC1 was down-regulated in various GC cell lines, significantly inhibited GC cell proliferation and invasion, and promote apoptosis, which might play an anti-oncogene role. Circ_SPECC1 was mainly located in the cytoplasm, and its sequence contained multiple potential binding sites of miR-526b. Pull-down experiments with biotinylated miR-526b mimics and circ_SPECC1 probe showed that they could enrich each other. RIP experiments found hat anti-AGO2 antibody could significantly enrich circ_SPECC1. Further dual luciferase reporter gene assay also confirmed that miR-526b could bind directly to circ_SPECC1. miR-526b was also down-regulated in GC cells, and one of its important target genes was KDM4A. Both circ_SPECC1 and miR-526b inhibited the expression of KDM4A and its downstream effector YAP1, but miR-526b inhibitors terminated the above-mentioned inhibition of circ_SPECC1, and KDM4A overexpression reversed the inhibition of circ_SPECC1 and miR-526b on YAP1 expression. Both miR-526b and KDM4A siRNA inhibited GC cell proliferation and invasion, and promote apoptosis; KDM4A overexpression had the opposite effects, and significantly blocked the regulation of miR-526b on cell growth and invasion. Therefore, circ_SPECC1 can enhance miR-526b inhibitory effect on downstream KDM4A/YAP1 pathway by adsorbing it, thus inhibiting GC cell growth and invasion. These findings enrich the mechanism of circRNAs in GC and will provide more new targets for the prevention and treatment of GC.

Overexpression of miR-623 suppresses progression of hepatocellular carcinoma via regulating the PI3K/Akt signaling pathway by targeting XRCC5

It has been reported that miR-623 is deregulated in lung adenocarcinoma and inhibits tumor growth and invasion. However, it is unclear whether miR-623 has a role in the progression of hepatocellular carcinoma (HCC). Herein, we found that miR-623 was significantly downregulated in HCC, and that its expression was related to poor clinical outcomes of patients with HCC. Upregulation of miR-623 decreased cell proliferation, viability, migration, and invasion and further promoted apoptosis in 7721, Huh7, and Bel-7402 cells. Moreover, we also observed that miR-623 regulated the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), Wnt/β-catenin, and extracellular regulated protein kinases/c-Jun N-terminal kinase (ERK/JNK) signaling pathways as well as the expression level of related proteins. Further, X-ray repair cross complementing 5 (XRCC5) was a direct target for miR-623, and the suppression of PI3K/Akt, Wnt/β-catenin, and ERK/JNK signaling pathways and cell proliferation and invasion abilities caused by miR-623 in HCC cells was significantly reversed by the upregulation of XRCC5. Collectively, our data suggested that miR-623 suppressed the progression of HCC by regulating the PI3K/Akt, Wnt/β-catenin, and ERK/JNK pathways by targeting XRCC5 in HCC in vitro, indicating that miR-623 may be a target for the therapy of HCC.

MiR-199a-5p suppresses non-small cell lung cancer via targeting MAP3K11

MicroRNAs (miRNAs) comprise a class of short, non-coding RNAs that directly target 3'UTR of mRNA, causing subsequent degradation or suppression of translation. Here, we verified that miR-199a-5p was significantly down-regulated in mouse NSCLC tissues and human patient samples. To further study the function of miR-199a-5p, lentivirus system was adopted to construct stably over-expressing miR-199a-5p A549, SPC-A1 and H1299 cell lines. Then, miR-199a-5p played a tumor suppression role via directly targeting MAP3K11 gene in non-small cell lung cancer (NSCLC). Elevated miR-199a-5p suppressed cell proliferation and arrested cell cycle in G1 phase. We found that MAP3K11 was negatively correlated with miR-199a-5p in NSCLC patient tissues and mouse xenograft tumors. Our results suggest that miR-199a-5p together with its target gene MAP3K11 is a key factor and constitutes a complicated regulation network in NSCLC.

miR-526b-3p serves as a prognostic factor and regulates the proliferation, invasion, and migration of glioma through targeting WEE1

Background: MicroRNAs play important roles in cancer progression including glioma. In this study, we aimed to explore the expression pattern, prognostic potential, and functional role of miR-526b-3p in human glioma.

Materials and methods: The expression of miR-526b-3p in glioma tissues and the adjacent non-tumor tissues was determined by quantitative RT-PCR. The chi-square test was performed to evaluate the statistical associations between miR-526b-3p level and patient characteristics. The prognostic value of miR-526b-3p was analyzed by Kaplan–Meier and Cox regression analyses. The function of miR-526b-3p was analyzed by MTT, colony formation assay, transwell assay, and flow cytometry analysis in vitro. The binding between miR-526b-3p and predicted target WEE1 was verified using dual luciferase assay and Western blot analysis.

Results: We found that miR-526b-3p expression was significantly downregulated in both glioma tissues and cell lines. Downregulation of miR-526b-3p was significantly associated with advanced WHO grade, lower KPS score, and inferior patient outcomes. Functional investigation indicated that overexpression of miR-526b-3p suppressed cell proliferation, migration, and invasion, and promoted apoptosis in glioma cell lines. Mechanically, WEE1 was identified as direct targets of miR-526b-3p and overexpression of WEE1 significantly suppressed the levels of WEE1. Moreover, re-introduction of WEE1 abrogates the suppression of motility and invasiveness induced by miR-526b-3p in glioma cells.

Conclusion: These findings indicate that miR-526b-3p may target WEE1 and inhibit glioma tumorigenesis and progression.

By downregulating PBX3, miR-526b suppresses the epithelial-mesenchymal transition process in cervical cancer cells

Aim: Research on novel mutant genes may develop the treatment of cervical cancer (CC). The role of miRNA-526b in epithelial-mesenchymal transition (EMT) of CC was investigated. Methods: The role and the molecular mechanism of miRNA-526b in CC and its effect on EMT were analyzed in clinical specimens and oncology experiments. Results: miRNA-526b was proved to be decreased in CC and associated with malignant clinicopathological characters. The character of miRNA-526b in EMT was also inspected in CC cells and tumor models. miRNA-526b was found to be able to inhibit the EMT property of CC cells by directly targeting PBX3. Conclusion: miRNA-526b restoration may be deliberated as a new treatment strategy of CC.

Long noncoding RNA LINC01296 induces non-small cell lung cancer growth and progression through sponging miR-5095

Long noncoding RNAs (lncRNAs) played in authentic biological cell roles such as cell apoptosis, cycle, differentiation, development, migration and invasion. However, the expression pattern and function of a new lncRNA LINC01296 in non-small cell lung cancer (NSCLC) are unknown and need to be studied. In our study, we indicate that the expression of LINC01296 was overexpressed in NSCLC samples compared to adjacent non-tumor tissues. Ectopic expression of LINC01296 promoted NSCLC cell proliferation and migration. Moreover, we demonstrated that LINC01296 has a potential binding site for miR-5095 by using online program tool StarBase. Overexpression of LINC01296 inhibited the expression of miR-5095 in the A549 cell. Furthermore, the miR-5095 expression was downregulated in the NSCLC tissues than in the adjacent non-tumor tissues. In addition, we found that there is a negative correlation between miR-5095 expression and LINC01296 level in the NSCLC tissues. Overexpression of miR-5095 suppressed NSCLC cell proliferation and migration. Finally, we demonstrate that ectopic expression of LINC01296 promoted cell proliferation and migration via inhibiting miR-5095 expression. These results suggested that LINC01296 might act a role as an oncogene in the tumorigenesis and development of NSCLC.

Entamoeba histolytica Up-Regulates MicroRNA-643 to Promote Apoptosis by Targeting XIAP in Human Epithelial Colon Cells

MicroRNAs (miRNAs) are small non-coding RNAs that function as negative regulators of gene expression. Recent evidences suggested that host cells miRNAs are involved in the progression of infectious diseases, but its role in amoebiasis remains largely unknown. Here, we reported an unexplored role for miRNAs of human epithelial colon cells during the apoptosis induced by Entamoeba histolytica. We demonstrated for the first time that SW-480 colon cells change their miRNAs profile in response to parasite exposure. Our data showed that virulent E. histolytica trophozoites induced apoptosis of SW-480 colon cells after 45 min interaction, which was associated to caspases-3 and -9 activation. Comprehensive profiling of 667 miRNAs using Taqman Low-Density Arrays showed that 6 and 15 miRNAs were significantly (FC > 1.5; p < 0.05) modulated in SW-480 cells after 45 and 75 min interaction with parasites, respectively. Remarkably, no significant regulation of the 6-miRNAs signature (miR-526b-5p, miR-150, miR-643, miR-615-5p, miR-525, and miR-409-3p) was found when SW-480 cells were exposed to non-virulent Entamoeba dispar. Moreover, we confirmed that miR-150, miR-643, miR-615-5p, and miR-525 exhibited similar regulation in SW-480 and Caco2 colon cells after 45 min interaction with trophozoites. Exhaustive bioinformatic analysis of the six-miRNAs signature revealed intricate miRNAs-mRNAs co-regulation networks in which the anti-apoptotic XIAP, API5, BCL2, and AKT1 genes were the major targets of the set of six-miRNAs. Of these, we focused in the study of functional relationships between miR-643, upregulated at 45 min interaction, and its predicted target X-linked inhibitor of apoptosis protein (XIAP). Interestingly, interplay of amoeba with SW-480 cells resulted in downregulation of XIAP consistent with apoptosis activation. More importantly, loss of function studies using antagomiRs showed that forced inhibition of miR-643 leads to restoration of XIAP levels and suppression of both apoptosis and caspases-3 and -9 activation. Congruently, mechanistic studies using luciferase reporter assays confirmed that miR-643 exerts a postranscripcional negative regulation of XIAP by targeting its 3′-UTR indicating that it's a downstream effector. In summary, we provide novel lines of evidence suggesting that early-branched eukaryote E. histolytica may promote apoptosis of human colon cells by modulating, in part, the host microRNome which highlight an unexpected role for miRNA-643/XIAP axis in the host cellular response to parasites infection.

Ku86 alleviates human umbilical vein endothelial cellular apoptosis and senescence induced by a low dose of ionizing radiation

Objective

The aim of this study was to observe the effect of Ku86 on cellular senescence and apoptosis induced by various doses of ionizing radiation in human umbilical vein endothelial cells (HUVECs).

Methods

Senescence-associated β-galactosidase activity was detected to evaluate cell senescence. Apoptosis was determined by flow cytometry and a caspase enzyme determination kit. p16^Ink4a, Sirt1, superoxide dismutase 2 (SOD2), xanthine oxidase (XOD), and Bcl-2 protein expression levels were measured by western blotting.

Results

Low doses of ionizing radiation induced cellular senescence and apoptosis in a dose-dependent manner. The Ku86 protein was negatively correlated with ionization intensity. After transfection of Ku86 with a vector (pcDNA 3.1), or interference with siRNA (si-Ku86), apoptosis/senescence and related protein expression were observed. Western blot results revealed that this induction of senescence was associated with activated Sirt1 and SOD2, and downregulation of p16^Ink4a and XOD in 0.2 Gy ionizing radiation. The expression levels of apoptosis-associated proteins, such as Bcl-2, cleaved caspase-3, caspase-8, and caspase-9, were significantly altered in both the presence and absence of Ku86 with ionizing radiation (0.2 Gy).

Conclusions

Our study revealed that Ku86 overexpression inhibits HUVEC apoptosis and senescence induced by low doses of ionizing radiation.

A Bioinformatics Approach to Explore MicroRNAs as Tools to Bridge Pathways Between Plants and Animals. Is DNA Damage Response (DDR) a Potential Target Process?

MicroRNAs, highly-conserved small RNAs, act as key regulators of many biological functions in both plants and animals by post-transcriptionally regulating gene expression through interactions with their target mRNAs. The microRNA research is a dynamic field, in which new and unconventional aspects are emerging alongside well-established roles in development and stress adaptation. A recent hypothesis states that miRNAs can be transferred from one species to another and potentially target genes across distant species. Here, we propose to look into the trans-kingdom potential of miRNAs as a tool to bridge conserved pathways between plant and human cells. To this aim, a novel multi-faceted bioinformatic analysis pipeline was developed, enabling the investigation of common biological processes and genes targeted in plant and human transcriptome by a set of publicly available Medicago truncatula miRNAs. Multiple datasets, including miRNA, gene, transcript and protein sequences, expression profiles and genetic interactions, were used. Three different strategies were employed, namely a network-based pipeline, an alignment-based pipeline, and a M. truncatula network reconstruction approach, to study functional modules and to evaluate gene/protein similarities among miRNA targets. The results were compared in order to find common features, e.g., microRNAs targeting similar processes. Biological processes like exocytosis and response to viruses were common denominators in the investigated species. Since the involvement of miRNAs in the regulation of DNA damage response (DDR)-associated pathways is barely explored, especially in the plant kingdom, a special attention is given to this aspect. Hereby, miRNAs predicted to target genes involved in DNA repair, recombination and replication, chromatin remodeling, cell cycle and cell death were identified in both plants and humans, paving the way for future interdisciplinary advancements.

Identification of differentially expressed miRNAs in early-stage cervical cancer with lymph node metastasis across The Cancer Genome Atlas datasets

Background and aim

Previous studies have suggested that lymph node metastasis (LNM) in early-stage cervical cancer (CESC) may affect the prognosis of patients and the outcomes of subsequent adjuvant therapy. However, research focused on miRNA expression in early-stage CESC patients with LNM remains limited. Therefore, it is necessary to identify prognostic miRNAs and determine their molecular mechanisms.

Methods

We evaluated the differentially expressed genes in early-stage CESC patients with LNM compared to patients without LNM and evaluated the prognostic significance of these differentially expressed genes by analyzing a public dataset from The Cancer Genome Atlas. Potential molecular mechanisms were investigated by gene ontology, the Kyoto Encyclopedia of Genes and Genomes, and protein–protein interaction network analyses.

Results

According to the The Cancer Genome Atlas data, hsa-miR-508, hsa-miR-509-2, and hsa-miR-526b expression levels were significantly lower in early-stage CESC patients with LNM than in patients without LNM. A multivariate analysis suggested that three miRNAs were prognostic factors for CESC (P<0.05). The target genes were identified to be involved in the MAPK, cAMP, PI3K/Akt, mTOR, and estrogen cancer signaling pathways. Protein–protein interaction network analysis showed that TP53, MMP1, NOTCH1, SMAD4, and NFKB1 were the most significant hub proteins.

Conclusion

Our results indicate that hsa-miR-508, hsa-miR-509-2, and hsa-miR-526b may be potential diagnostic biomarkers for early-stage CESC with LNM, and serve as prognostic predictors for patients with CESC.

Functional validation of miRNAs targeting genes of DNA double-strand break repair to radiosensitize non-small lung cancer cells

DNA-Double strand breaks (DSBs) generated by radiation therapy represent the most efficient lesions to kill tumor cells, however, the inherent DSB repair efficiency of tumor cells can cause cellular radioresistance and impact on therapeutic outcome. Genes of DSB repair represent a target for cancer therapy since their down-regulation can impair the repair process making the cells more sensitive to radiation. In this study, we analyzed the combination of ionizing radiation (IR) along with microRNA-mediated targeting of genes involved in DSB repair to sensitize human non-small cell lung cancer (NSCLC) cells. MicroRNAs are natural occurring modulators of gene expression and therefore represent an attractive strategy to affect the expression of DSB repair genes. As possible IR-sensitizing targets genes we selected genes of homologous recombination (HR) and non-homologous end joining (NHEJ) pathway (i.e. RAD51, BRCA2, PRKDC, XRCC5, LIG1). We examined these genes to determine whether they may be real targets of selected miRNAs by functional and biological validation. The in vivo effectiveness of miRNA treatments has been examined in cells over-expressing miRNAs and treated with IR. Taken together, our results show that hsa-miR-96-5p and hsa-miR-874-3p can directly regulate the expression of target genes. When these miRNAs are combined with IR can decrease the survival of NSCLC cells to a higher extent than that exerted by radiation alone, and similarly to radiation combined with specific chemical inhibitors of HR and NHEJ repair pathway.

Regulation of DNA Double-Strand Break Repair by Non-Coding RNAs

DNA double-strand breaks (DSBs) are deleterious lesions that are generated in response to ionizing radiation or replication fork collapse that can lead to genomic instability and cancer. Eukaryotes have evolved two major pathways, namely homologous recombination (HR) and non-homologous end joining (NHEJ) to repair DSBs. Whereas the roles of protein-DNA interactions in HR and NHEJ have been fairly well defined, the functions of small and long non-coding RNAs and RNA-DNA hybrids in the DNA damage response is just beginning to be elucidated. This review summarizes recent discoveries on the identification of non-coding RNAs and RNA-mediated regulation of DSB repair.

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.

Role of long non-coding RNA in drug resistance in non-small cell lung cancer

Lung cancer is the leading cause of cancer-associated death, and non-small cell lung cancer (NSCLC) accounts for 85% of all lung cancer cases. Many drugs have been used to treat NSCLC in order to improve patient prognosis. Platinum-based chemotherapy is the first-line treatment for locally advanced or metastatic patients. For patients with activating EGFR mutations, tyrosine kinase inhibitors are the best treatment choice. NSCLC initially exhibits an excellent response to treatment; however, acquired resistance has been observed in many patients, leading to ineffective treatment. Clinical resistance is an impediment in the treatment of patients with advanced NSCLC. Many sequencing technologies have shown that long non-coding RNA (lncRNA) is expressed differently between drug-resistant and drug-sensitive lung cancer cells. We review the literature on lncRNA in drug resistance of NSCLC. The aim of this review is to gain insight into the molecular mechanisms of drug resistance, mainly focusing on the role of lncRNA in NSCLC.

MicroRNA-411 promoted the osteosarcoma progression by suppressing MTSS1 expression

MicroRNAs (miRNAs) play crucial roles in the progression of different tumors. In our study, we investigated the expression and roles of miR-411 in human osteosarcoma. In this study, we first confirmed that the miR-411 expression was higher in the serum of patients with osteosarcoma than in the serum of healthy volunteers. In addition, we found that the miR-411 expression was upregulated in the osteosarcoma tissues compared to that in the matched normal bone tissues. We also demonstrated that the miR-411 expression was upregulated in the four osteosarcoma cell lines. Elevated expression of miR-411 promoted osteosarcoma cell proliferation and migration. Moreover, we identified that metastasis suppressor protein 1 (MTSS1) was a direct target gene of miR-411 in the osteosarcoma cell. We also demonstrated that the MTSS1 expression was downregulated in the osteosarcoma tissues compared to that in the matched normal bone tissues. In addition, MTSS1 expression level was inversely correlated with miR-411 expression in the osteosarcoma tissues. Furthermore, elevated expression of miR-411 enhanced the osteosarcoma cell proliferation and migration through inhibiting the MTSS1 expression. These data suggested that miR-411 played as oncogene in the osteosarcoma partly by inhibiting the MTSS1 expression.

MiR-652-3p is upregulated in non-small cell lung cancer and promotes proliferation and metastasis by directly targeting Lgl1

Our previous study found that miR-652-3p is markedly upregulated in the serum of patients with NSCLC and suggesting that miR-652-3p is a potential biomarker for the early diagnosis of NSCLC. In this study, we detected the expression of miR-652-3p in NSCLC tumor tissues and cell lines and investigated the effect of miR-652-3p on the proliferation and metastasis of NSCLC cells. Our results showed that the expression of miR-652-3p was significantly upregulated in tumor tissues of 50 patients with NSCLC, and it was significantly higher in patients with positive lymph node metastasis, advanced TNM stage and poor prognosis. Using functional analyses by overexpressing or suppressing miR-652-3p in NSCLC cells, we demonstrated that miR-652-3p promoted cell proliferation, migration, invasion and inhibited cell apoptosis. Moreover, the lethal(2) giant larvae 1 (Lgl1) was identified as a direct and functional target of miR-652-3p. Overexpression or knockdown of miR-652-3p led to decreased or increased expression of Lgl1 protein, and the binding site mutation of LLGL1 3'UTR abrogated the responsiveness of the luciferase reporters to miR-652-3p. Overexpression of Lgl1 partially attenuated the function of miR-652-3p. Collectively, these results revealed that miR-652-3p execute a tumor-promoter function in NSCLC through direct binding and regulating the expression of Lgl1.

microRNA-526b servers as a prognostic factor and exhibits tumor suppressive property by targeting Sirtuin 7 in hepatocellular carcinoma

Recent studies have reported that microRNA-526b (miR-526b) is implicated in the growth and metastasis of cancer cells. However, the clinical significance of miR-526b and its role as well as underlying mechanisms are largely unknown in hepatocellular carcinoma (HCC). Here, we detected miR-526b expression difference between HCC and matched nontumor tissues with qRT-PCR. We found that miR-526b displayed lower expression in HCC patient tissues and cells. Clinical analysis revealed that low miR-526b expression correlated with large tumor size, venous infiltration, advanced tumor-node-metastasis (TNM) stage. Furthermore, miR-526b underexpression independently predicted poor prognosis of HCC patients. Functionally, we demonstrated that miR-526b inhibited proliferation, migration and invasion of HCC cells in vitro. Moreover, miR-526b overexpression restrained the tumor growth and pulmonary metastasis in vivo. Mechanistically, we proved that miR-526b could directly bind to 3′UTR of sirtuin 7 (SIRT7) mRNA and repressed its expression. miR-526b and SIRT7 showed a negative correlation in HCC tissues. More importantly, up-regulating SIRT7 expression antagonized miR-526b-inhibited proliferation, migration and invasion in SMMC-7721 cells. Furthermore, miR-526b suppressed epithelial-to-mesenchymal transition (EMT) of HCC cells. Immunoblotting analysis indicated that miR-526b reduced the levels of phosphorylated ERK (p-ERK), c-Myc, Cyclin D1, c-Jun, SNAIL and SLUG in HCC cells. SIRT7 restoration promoted phosphorylation of ERK and EMT in miR-526b overexpressing SMMC-7721 cells. Taken together, this is the first time we demonstrated that miR-526b might function as a prognostic biomarker and suppressed SIRT7 expression, and subsequently led to the growth and metastasis of HCC. Our findings provide miR-526b/SIRT7 axis as a promising drug target for HCC.

BANCR: a cancer-related long non-coding RNA

Long non-coding RNAs (lncRNAs) are a group of non-protein-coding RNAs with more than 200 nucleotides in length. lncRNAs are involved in diverse biological processes, including development, cell proliferation and differentiation. Emerging evidences also suggest that lncRNAs may participate in cancer development by functioning as tumor suppressors and oncogenes. BRAF-activated non-coding RNA (BANCR) was first identified as an oncogene in melanoma. Later studies demonstrated that BANCR was frequently deregulated in human cancers, including lung cancer, gastric cancer, colorectal cancer, thyroid cancer and osteosarcoma. Nevertheless, the direction of deregulation was tissue-specific in which BANCR could as an oncogene or tumor-suppressor gene. In this review, we compile current evidences concerning the functional roles and molecular mechanisms of BANCR in tumor development.

MicroRNA-526a targets p21-activated kinase 7 to inhibit tumorigenesis in hepatocellular carcinoma

MicroRNAs belong to a series of noncoding RNAs and have diverse roles in several biological processes. The association between aberrant microRNA expression and tumorigenesis is complex and remains to be fully elucidated. The present study investigated whether microRNA (miR) ‑526a can suppress the progression of hepatocellular carcinoma (HCC) in vitro and in vivo. Reverse transcription‑quantitative polymerase chain reaction, luciferase reporter assay, invasion assay, western blotting and in vivo implantation were used to investigate the potential function of miR‑526a. The present study observed that the level of miR‑526a was downregulated in HCC tissues and well‑established cell lines. In addition, the ectopic introduction of miR‑526a into Huh7 and HepG2 cells significantly attenuated HCC tumorigenesis, including proliferation, migration and invasion. The growth of tumor xenografts was also inhibited following transfection with miR‑526a. Using overlapping strategies, p21‑activated kinase 7 (PAK7) was predicted to be a target for miR‑526a, and this was verified experimentally. An inverse correlation was found between miR‑526a and PAK7 in HCC tissues. The results of the present study revealed a novel function of miR‑526a and may provide crucial insight into therapeutic interventions targeting microRNAs.

Ku80 correlates with neoadjuvant chemotherapy resistance in human lung adenocarcinoma, but reduces cisplatin/pemetrexed-induced apoptosis in A549 cells

Background

Ku80 is a DNA repair protein which involves in cell apoptosis and chemoresistance. However, it is unclear whether Ku80 correlates with the efficiency of neoadjuvant chemotherapy in human lung adenocarcinoma, and modulates cisplatin/pemetrexed-induced lung cancer cell apoptosis in vitro.

Methods

We recruited 110 patients with stage IIIA lung adenocarcinoma, who received 2 cycles of neoadjuvant chemotherapy, and their lungs were reevaluated by CT scan. Immunohistochemistry and qRT-PCR was performed to detect the expression level of Ku80. A549 cells were transfected by lentiviral vector containing shRNA and full length cDNA to knockdown or upregulate Ku80 gene expression. CCK8 assay, flow cytometry and Western blot were employed to determine the viability and apoptosis of A549 cells treated with cisplatin combined with pemetrexed.

Results

Ku80 expression was detected in 76 patients (69%). There were 38 patients who responded to chemotherapy, where Ku80 was positively expressed in 7 cases (18.4%). Immunohistochemical score of Ku80 protein in the response group (2.079 ± 1.617) to chemotherapy was lower than that in the nonresponse group (5.597 ± 2.114, P < 0.05). Tissue samples from the nonresponse group exhibited higher Ku80 mRNA levels compared to the response group. Ku80 knockdown by shRNA augmented cisplatin/pemetrexed-induced decline in viability, whereas Ku80 overexpression attenuated viability reduction induced by these drugs compared to control A549 cells. Both flow cytometry and Western blot analysis displayed that the apoptotic rate of Ku80 shRNA-transfected A549 cells was significantly increased compared to control cells treated with cisplatin/pemetrexed, which was lowered by Ku80 overexpression.

Conclusion

Ku80 could predict the probability of resistance to neoadjuvant chemotherapy in lung adenocarcinoma, and reduced cisplatin and pemetrexed-induced apoptosis in A549 cells.

MicroRNAs, DNA Damage Response, and Cancer Treatment

As a result of various stresses, lesions caused by DNA-damaging agents occur constantly in each cell of the human body. Generally, DNA damage is recognized and repaired by the DNA damage response (DDR) machinery, and the cells survive. When repair fails, the genomic integrity of the cell is disrupted—a hallmark of cancer. In addition, the DDR plays a dual role in cancer development and therapy. Cancer radiotherapy and chemotherapy are designed to eliminate cancer cells by inducing DNA damage, which in turn can promote tumorigenesis. Over the past two decades, an increasing number of microRNAs (miRNAs), small noncoding RNAs, have been identified as participating in the processes regulating tumorigenesis and responses to cancer treatment with radiation therapy or genotoxic chemotherapies, by modulating the DDR. The purpose of this review is to summarize the recent findings on how miRNAs regulate the DDR and discuss the therapeutic functions of miRNAs in cancer in the context of DDR regulation.

LncRNA-RMRP Acts as an Oncogene in Lung Cancer

Accumulating studies have demonstrated that long noncoding RNAs (lncRNAs) act a crucial role in the development of tumors. However, the role of lncRNAs in lung cancer remains largely unknown. In this study, we demonstrated that theexpression of RMRP was upregulated in lung adenocarcinoma tissues compared to the matched adjacent normal tissues. Moreover, of 35 lung adenocarcinoma samples, RMRP expression was upregulated in 25 cases (25/35; 71.4%) compared to the adjacent normal tissues. We also showed that RMRP expression was upregulated in lung adenocarcinoma cell lines (A549, SPC-A1, H1299 and H23) compared to the bronchial epithelial cell line (16HBE). Ectopic expression of RMRP promoted lung adenocarcinoma cell proliferation, colony formation and invasion. In addition, overexpression of RMRP inhibited the miR-206 expression in the H1299 cell and increased the KRAS, FMNL2 and SOX9 expression, which were the target genes of miR-206. Re-expression of miR-206 reversed the RMRP-induced the H1299 cell proliferation and migration. Our data proved that RMRP acted as an oncogene LncRNA to promote the expression of KRAS, FMNL2 and SOX9 by inhibiting miR-206 expression in lung cancer. These data suggested that RMRP might serve as a therapeutic target in lung adenocarcinoma.

Hsa-miR-623 suppresses tumor progression in human lung adenocarcinoma

Our previous study revealed that Ku80 was overexpressed in lung cancer tissues and hsa-miR-623 regulated the Ku80 expression; however, the detailed function of hsa-miR-623 in lung cancer was unclear. We identified that hsa-miR-623 bound to the 3'-UTR of Ku80 mRNA, thus significantly decreasing Ku80 expression in lung adenocarcinoma cells. Hsa-miR-623 was downregulated in lung adenocarcinoma tissues compared with corresponding non-tumorous tissues, and its expression was inversely correlated with Ku80 upregulation. Downregulation of hsa-miR-623 was associated with poor clinical outcomes of lung adenocarcinoma patients. Hsa-miR-623 suppressed lung adenocarcinoma cell proliferation, clonogenicity, migration and invasion in vitro. Hsa-miR-623 inhibited xenografts growth and metastasis of lung adenocarcinoma in vivo. Ku80 knockdown in lung adenocarcinoma cells suppressed tumor properties in vitro and in vivo similar to hsa-miR-623 overexpression. Further, hsa-miR-623 overexpression decreased matrix metalloproteinase-2 (MMP-2) and MMP-9 expression levels, with decreased ERK/JNK phosphorylation. Inhibition of hsa-miR-623 or overexpression of Ku80 promoted lung adenocarcinoma cell invasion, activated ERK/JNK phosphorylation and increased MMP-2/9 expressions, which could be reversed by ERK kinase inhibitor or JNK kinase inhibitor. In summary, our results showed that hsa-miR-623 was downregulated in lung adenocarcinoma and suppressed the invasion and metastasis targeting Ku80 through ERK/JNK inactivation mediated downregulation of MMP-2/9. These findings reveal that hsa-miR-623 may serve as an important therapeutic target in lung cancer therapy.

A genetic polymorphism at miR-526b binding-site in the lincRNA-NR_024015 exon confers risk of esophageal squamous cell carcinoma in a population of North China

Esophageal squamous cell carcinoma (ESCC) may be caused by a combination of environmental factors and genetic variants. The present study was to evaluate the association between haplotype-tagging SNPs (htSNPs) of lincRNA-NR_024015 and the risk of ESCC. We selected htSNPs across the whole 1469 bp lincRNA-NR_024015 locus and 2 kb upstream as well as 2 kb downstream regions of the gene and conducted a case-control study in 581 ESCC cases and 677 healthy controls to test the effects of functional lincRNA-NR_024015 htSNPs on ESCC susceptibility. Of the seven potential functional htSNPs, rs8506 AA genotype was found to be associated with increased risk of ESCC. Further stratification analysis showed that the risk effect was more pronounced in male patients and patients with TNM stage III and IV. LincRNA-NR_024015 was predominantly expressed in cytoplasm of esophageal cancer cells. The expression level of lincRNA-NR_024015 in ESCC tumor tissues was significantly higher than that in corresponding normal tissues and rs8506 genotype has a genotype-specific effect on lincRNA-NR_024015 expression. Furthermore, rs8506 G to A variant might influence lincRNA-NR_024015 expression and function by disrupting the binding of hsa-miR-526b to the site. High expression level of lincRNA-NR_024015 and rs8506 A allele were associated with poor ESCC patients' survival. These findings indicate that functional polymorphism rs8506 G>A in lincRNA-NR_024015 exon may be a genetic modifier for the development of ESCC and lincRNA-NR_024015 may be a useful marker for the prediction of the biological behavior of ESCC. © 2016 Wiley Periodicals, Inc.

MicroRNA‑187 is an independent prognostic factor in lung cancer and promotes lung cancer cell invasion via targeting of PTRF

MicroRNAs (miRNAs) are involved in the progression of different types of cancers giving new hope for cancer treatment. The role and regulatory mechanism of microRNA‑187 (miR‑187) are largely unknown. In the present study, 74 patients with non‑small cell lung cancer (NSCLC) were selected. Tumor tissues and matched normal tissues were collected for determining the expression level of miR‑187. Cell research was performed to detect the function of miR‑187. The expression level was measured and miR‑187 was found to be overexpressed in the NSCLC cell lines and tissues. Overexpression of miR‑187 promoted cell proliferation in the A549 and H1650 cell lines. Moreover, overexpression of miR‑187 also promoted cell migration and invasion. Polymerase I and transcript release factor (PTRF) was identified as a target of miR‑187. Overexpression of miR‑187 suppressed the expression of PTRF. Knockdown of PTRF promoted lung cancer cell invasion, and overexpression of PTRF had a negative effect on lung cancer cell invasion. The PTRF messenger RNA (mRNA) levels in cancer tissues were significantly lower than those in their adjacent normal lung tissues as determined by real‑time PCR (RT‑PCR). The expression of the PTRF protein was significantly weaker than that in the adjacent normal lung tissues using immunohistochemical staining. The findings revealed that miR‑187 promotes cell growth and invasion by targeting PTRF and miR‑187 may be a new prognostic factor for NSCLC.

BRD7 Acts as a Tumor Suppressor Gene in Lung Adenocarcinoma

Lung cancer is one of the most malignant tumors and the leading cause of cancer-related deaths worldwide. Among lung cancers, 40% are diagnosed as adenocarcinoma. Bromodomain containing 7 (BRD7) is a member of bromodomain-containing protein family. It was proved to be downregulated in various cancers. However, the role of BRD7 in lung adenocarcinoma is still unknown. Western blot and qRT-PCR was performed to measure the BRD7 expression in lung adenocarcinoma tissues and cells. CCK8 and migration assay was done to detect the functional role of BRD7 in lung adenocarcinoma. In this study, we showed that the expression of BRD7 was downregulated in lung adenocarcinoma tissues and cells. The lower of BRD7 levels in patients with lung adenocarcinoma was associated with shortened disease-free survival. Furthermore, overexpression of BRD7 inhibited lung adenocarcinoma cell proliferation and migration. Inhibition of BRD7 expression promoted cell proliferation and migration by activating ERK phosphorylation. Overexpression of BRD7 inhibited cyclin D and myc expression. Our findings are consistent with a tumor suppressor role for BRD7 in lung adenocarcinoma tumorigenesis.

miR-526b targets 3' UTR of MMP1 mRNA

Regulation of matrix metalloproteinases (MMPs) is important for many physiological processes involving cancers, inflammation, tissue remodeling and skin aging. Here, we report the novel finding that the expression of MMP1 mRNA is downregulated by the overexpression of miR-526b which is a member of chromosome 19 microRNA cluster (C19MC). Our analysis using reporter constructs containing the 3' untranslated region (3' UTR) of MMP1 and its mutant form showed that the region from 377-383 in the 3' UTR of MMP1 is critical for targeting by miR-526b. In addition, the expression pattern of miR-526b and MMP1 mRNA showed reverse relation between adult dermal and neonatal fibroblasts. We show for the first time that miR-526b, an miRNA belonging to C19MC, can target the 377-383 region of the MMP1 3' UTR.

miR-211 promotes non-small cell lung cancer proliferation by targeting SRCIN1

MicroRNAs (miRNAs) are a class of small non-coding RNAs that, when dysregulated, are involved in the initiation and progression of various cancers, including lung cancer, in humans. In the current study, qRT-PCR was performed to measure miR-211 expression in human non-small cell lung cancer (NSCLC) cell lines and tissues. Cell proliferation, cell cycle, colony formation, and invasion were performed to detect the functional role of miR-211 in human NSCLC cell line. We used luciferase reporter assay to find the potential target of miR-211. We found that miR-211 expression was upregulated in human non-small cell lung cancer (NSCLC) cell lines and tissues. The overexpression of miR-211 enhanced NSCLC cell proliferation, colony formation, and invasion. SRC kinase signaling inhibitor 1 (SRCIN1) was identified as a direct target of miR-211. SRCIN1 silencing promoted cell proliferation, and SRCIN1 expression was downregulated in human NSCLC cell lines. Thus, miR-211 may function as an oncogenic miRNA in NSCLC, partly by regulating SRCIN1, and the modulation of miR-211 expression represents a potential strategy for the treatment of NSCLC patients.