Knockdown of lncRNA PCAT6 Enhances Radiosensitivity in Triple-Negative Breast Cancer Cells by Regulating miR-185-5p/TPD52 Axis

Mechanisms of radioresistance and radiosensitization strategies for Triple Negative Breast Cancer

Breast cancer is one of the most common malignant tumors in women. Triple-negative breast cancer (TNBC) is a molecular subtype of breast cancer that is characterized by a high risk of recurrence and poor prognosis. With the increasingly prominent role of radiotherapy in TNBC treatment, patient resistance to radiotherapy is an attractive area of clinical research. Gene expression changes induced by multiple mechanisms can affect the radiosensitivity of TNBC cells to radiotherapy through a variety of ways, and the enhancement of radioresistance is an important factor in the malignant progression of TNBC. The above pathways mainly include DNA damage repair, programmed cell death, cancer stem cells (CSC), antioxidant function, tumor microenvironment, and epithelial-mesenchymal transition (EMT) pathway. Tumor cells can reduce the damage of radiotherapy to themselves through the above ways, resulting in radioresistance. Therefore, in this review, we aim to summarize the strategies for immunotherapy combined with radiotherapy, targeted therapy combined with radiotherapy, and epigenetic therapy combined with radiotherapy to identify the best treatment for TNBC and improve the cure and survival rates of patients with TNBC. This review will provide important guidance and inspiration for the clinical practice of radiotherapy for TNBC, which will help deepen our understanding of this field and promote its development.

Non-coding RNAs modulation in breast cancer radioresponse: mechanisms and therapeutic implications

Breast cancer is the most frequent type of cancer in women, with significant incidence and fatality rates. Radiation therapy is an important therapeutic option for breast cancer patients. However, tumor cells' resistance to radiation can limit therapy efficacy, resulting in recurrence and death. Non-coding RNAs (ncRNAs) are a class of small RNA molecules that do not translate into proteins but can affect the translation of target mRNA. Several investigations on breast cancer have demonstrated abnormal expression of ncRNAs in response to radiation. Non-coding RNAs are essential in controlling numerous processes such as DNA damage response, cancer stem cell pathways, cell cycle regulation, cell death, and inflammation. Dysregulation of ncRNAs after irradiation influences radiosensitivity or radioresistance of breast cancer cells. Understanding the molecular mechanisms underlying Radiation response can lead to innovative treatment ways to reduce breast cancer radioresistance and increase radiotherapy's efficacy. This review summarizes current research on ncRNA dysregulation following irradiation and analyzes ncRNAs' function and mechanism in modifying breast cancer cell radiosensitivity and radioresistance.

Exploring the clinical potential of circulating LncRNAs in breast cancer: insights into primary signaling pathways and therapeutic interventions

Breast cancer (BC) occupies the top spot among women on a global scale. The tumor has a significant degree of heterogeneity, displaying a notable prevalence of medication resistance, recurrence, and metastasis, rendering it one of the most lethal forms of malignant neoplasms. The timely identification, ongoing evaluation of therapeutic interventions, and accurate prediction of outcomes play crucial roles in determining the overall survival rates of women with BC. Nevertheless, the absence of precise biomarkers remains a significant determinant impacting the overall well-being and both the physical and emotional health of BC patients. Long noncoding RNA (lncRNA) exerts regulatory control over several genes and signaling pathways, hence assuming crucial roles in the development of neoplastic growth. Recently, research has indicated that the atypical expression of circulating lncRNAs in various biological bodily fluids has a noteworthy impact on the early detection, pathological categorization, staging, monitoring of therapy outcomes, and evaluation of prognosis in cases of BC. This article aims to assess the potential clinical utility of circulating lncRNAs in the context of BC focusing on specific primary signaling pathways; Wnt/β-catenin, Notch, TGF-β, and hedgehog (Hh), in addition to some therapeutic interventions.

Non-coding RNAs as modulators of radioresponse in triple-negative breast cancer: a systematic review

Triple-negative breast cancer (TNBC), characterized by high invasiveness, is associated with poor prognosis and elevated mortality rates. Despite the development of effective therapeutic targets for TNBC, systemic chemotherapy and radiotherapy (RdT) remain prevalent treatment modalities. One notable challenge of RdT is the acquisition of radioresistance, which poses a significant obstacle in achieving optimal treatment response. Compelling evidence implicates non-coding RNAs (ncRNAs), gene expression regulators, in the development of radioresistance. This systematic review focuses on describing the role, association, and/or involvement of ncRNAs in modulating radioresponse in TNBC. In adhrence to the PRISMA guidelines, an extensive and comprehensive search was conducted across four databases using carefully selected entry terms. Following the evaluation of the studies based on predefined inclusion and exclusion criteria, a refined selection of 37 original research articles published up to October 2023 was obtained. In total, 33 different ncRNAs, including lncRNAs, miRNAs, and circRNAs, were identified to be associated with radiation response impacting diverse molecular mechanisms, primarily the regulation of cell death and DNA damage repair. The findings highlighted in this review demonstrate the critical roles and the intricate network of ncRNAs that significantly modulates TNBC's responsiveness to radiation. The understanding of these underlying mechanisms offers potential for the early identification of non-responders and patients prone to radioresistance during RdT, ultimately improving TNBC survival outcomes.

LncRNA PCAT6 mediates UBFD1 expression via sponging miR-545-3p in breast cancer cells

Background

LncRNA PCAT6 has been shown to involve in carcinogenesis of different tumors. In this study, we investigated underline mechanism by which PCAT6 promoted breast cancer cell progression.

Methods

RIP was used to identify lncRNAs associated with IMP1. Bioinformatics assays were used to predict potential miRNAs that interact with PCAT6 and mRNAs that are targeted by miR-545-3p. RNA-seq and RT-qPCR were used to analyze differential expression of lncRNAs and miRNA-targeted genes. Luciferase reporter and RNA pull-down assays were performed to identify the molecular interactions between PCAT6 and individual miRNAs. The role of PCAT6-mediated cell proliferation and invasion were tested by CCK-8 and transwell assays following loss-of-function and gain-of-function effects.

Results

We identified that PCAT6 is one of the lncRNAs that associated with IMP1. PCAT6 not only binds to IMP1, but also acts as a ceRNA to interact with multiple miRNAs, including miR-545-3p. Binding of IMP1 destabilized PCAT6, while competitive interaction with miR-545-3p allowed PCAT6 to positively regulate UBFD1 expression. Silencing UBFD1 mRNA could effectively rescue PCAT6-induced cell proliferation and invasive abilities.

Conclusions

Our study provided evidence that PCAT6 activates UBFD1 expression via sponging miR-545-3p to increase carcinogenesis of breast cancer cells. Based on the nature of UBFD1 as a polyubiquitin binding protein, our study suggested that ubiquitin pathway might contribute to breast cancer progression.

Long noncoding RNA FTX promotes epithelial-mesenchymal transition of epithelial ovarian cancer through modulating miR-7515/TPD52 and activating Met/Akt/mTOR

Overexpressed long noncoding RNA FTX is associated with low survival rate of epithelial ovarian cancer (EOC) patients, and enhances tumor infiltration. Thus, we aim to illuminate the undefined underlying mechanisms. Real-time quantitative polymerase chain reaction was applied to detect the expressions of FTX, miR-7515, miR-342-3p, miR-940, miR-150-5p, miR-205-5p and tumor protein D52 (TPD52). Cell counting kit-8 and transwell assays were utilized to explore the cell viability, migration or invasion of EOC cells. Western blot was conducted to measure the expressions of E-cadherin, N-cadherin, Met, phosphorylated (p)-Met, Akt, p-Akt, mTOR and p-mTOR. LncBase and TargetScan predicted the binding of miR-7515 with FTX, and the binding of TPD52 with miR-7515, respectively. The two bindings were further validated by dual luciferase reporter assay. As a result, FTX sponged miR-7515 and miR-7515 targeted to TPD52. FTX was overexpressed in four EOC cell lines. Overexpressed FTX enhanced the cell viability, migration or invasion of EOC cells, elevated N-cadherin and TPD52 expressions, phosphorylated Met/Akt/mTOR, and inhibited E-cadherin expression. All these influences were subsequently reversed by miR-7515 mimic. Collectively, FTX regulates miR-7515/TPD52 to facilitate the migration, invasion or epithelial-mesenchymal transition of EOC through activating Met/Akt/mTOR signaling pathway.

Multigenerational genetic effects of paternal cadmium exposure on ovarian granulosa cell apoptosis

To explore whether paternal cadmium (Cd) exposure causes ovarian granulosa cell (GC) apoptosis in offspring and the multigenerational genetic effects. From postnatal day 28 (PND28) until adulthood (PND56), SPF male Sprague-Dawley (SD) rats were gavaged daily with varying concentrations of CdCl_2. (0, 0.5, 2, and 8 mg/kg). After treatment, the F1 generation was produced by mating with untreated female rats, and the F1 generation male rats were mated with untreated female rats to produce the F2 generation. Apoptotic bodies (electron microscopy) and significantly higher apoptotic rates (flow cytometry) were observed in both F1 and F2 ovarian GCs following paternal Cd exposure. Moreover, the mRNA (qRTPCR) or protein (Western blotting) levels of bax, bcl2, bcl-xl, caspase 3, caspase 8, and caspase 9 were changed to varying degrees. Apoptosis-related miRNAs (qRTPCR) and methylation modifications of apoptosis-related genes (bisulfite-sequencing PCR) in ovarian GCs were further detected. Compared with those of controls, the expression patterns of miRNAs in F1 and F2 offspring were different after paternal Cd exposure, while the average methylation level of apoptosis-related genes did not change significantly (except for individual loci). In summary, there are paternal genetic intergenerational and transgenerational effects on ovarian GC apoptosis induced by paternal Cd exposure. These genetic effects were related to the upregulation of BAX, BCL-XL, Cle-CASPASE 3, and Cle-CASPASE 9 in F1 and the upregulation of Cle-CASPASE 3 in F2 progeny. Important changes in apoptosis-related miRNAs were also observed.

Recent Clinical Advances on Long Non-Coding RNAs in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a more aggressive type of breast cancer due to its heterogeneity and complex molecular mechanisms. TNBC has a high risk for metastasis, and it is difficult to manage clinical conditions of the patients. Various investigations are being conducted to overcome these challenges using RNA, DNA, and proteins for early diagnosis and treatment. Recently, long non-coding RNAs (lncRNAs) have emerged as a novel target to treat the multistep process of TNBC. LncRNAs regulate epigenetic expression levels, cell proliferation and apoptosis, and tumour invasiveness and metastasis. Thus, lncRNA-based early diagnosis and treatment options could be helpful, especially for patients with severe TNBC. lncRNAs are expressed in a highly specific manner in cells and tissues and are involved in TNBC progression and development. lncRNAs could be used as sensitive and specific targets for diagnosis, treatment, and monitoring of patients with TNBC. Therefore, the exploration of novel diagnostic and prognostic biomarkers is of extreme importance. Here, we discuss the molecular advances on lncRNA regulation of TNBC and lncRNA-based early diagnosis, treatment, and drug resistance.

Role of microRNA/lncRNA Intertwined With the Wnt/β-Catenin Axis in Regulating the Pathogenesis of Triple-Negative Breast Cancer

Objective (s): In this mini-review, we aimed to discuss the Wnt/β-catenin signaling pathway modulation in triple-negative breast cancer, particularly the contribution of lncRNAs and miRNAs in its regulation and their possible entwining role in breast cancer pathogenesis, proliferation, migration, or malignancy.

Background: Malignant tumor formation is very high for breast cancer in women and is a leading cause of death all over the globe. Among breast cancer subtypes, triple-negative breast cancer is rife in premenopausal women, most invasive, and prone to metastasis. Complex pathways are involved in this cancer’s pathogenesis, advancement, and malignancy, including the Wnt/β-catenin signaling pathway. This pathway is conserved among vertebrates and is necessary for sustaining cell homeostasis. It is regulated by several elements such as transcription factors, enhancers, non-coding RNAs (lncRNAs and miRNAs), etc.

Methods: We evaluated lncRNAs and miRNAs differentially expressed in triple-negative breast cancer (TNBC) from the cDNA microarray data set literature survey. Using in silico analyses combined with a review of the current literature, we anticipated identifying lncRNAs and miRNAs that might modulate the Wnt/β-catenin signaling pathway.

Result: The miRNAs and lncRNAs specific to triple-negative breast cancer have been identified based on literature and database searches. Tumorigenesis, metastasis, and EMT were all given special attention. Apart from cross-talk being essential for TNBC tumorigenesis and treatment outcomes, our results indicated eight upregulated and seven downregulated miRNAs and 19 upregulated and three downregulated lncRNAs that can be used as predictive or diagnostic markers. This consolidated information could be useful in the clinic and provide a combined literature resource for TNBC researchers working on the Wnt/β-catenin miRNA/lncRNA axis.

Conclusion: In conclusion, because the Wnt pathway and miRNAs/lncRNAs can modulate TNBC, their intertwinement results in a cascade of complex reactions that affect TNBC and related processes. Their function in TNBC pathogenesis has been highlighted in molecular processes underlying the disease progression.

Radiation therapy for triple-negative breast cancer: emerging role of microRNAs as biomarkers and radiosensitivity modifiers. A systematic review

PURPOSE

Radiation therapy (RT) for triple-negative breast cancer (TNBC) treatment is currently delivered in the adjuvant setting and is under investigation as a booster of neoadjuvant treatments. However, TNBC radioresistance remains an obstacle, so new biomarkers are needed to select patients for any integration of RT in the TNBC therapy sequence. MicroRNAs (miRs) are important regulators of gene expression, involved in cancer response to ionizing radiation (IR) and assessable by tumor tissue or liquid biopsy. This systematic review aimed to evaluate the relationships between miRs and response to radiation in TNBC, as well as their potential predictive and prognostic values.

METHODS

A thorough review of studies related to miRs and RT in TNBC was performed on PubMed, EMBASE, and Web of Science. We searched for original English articles that involved dysregulation of miRs in response to IR on TNBC-related preclinical and clinical studies. After a rigorous selection, 44 studies were chosen for further analysis.

RESULTS

Thirty-five miRs were identified to be TNBC related, out of which 21 were downregulated, 13 upregulated, and 2 had a double-side expression in this cancer. Expression modulation of many of these miRs is radiosensitizing, among which miR-7, -27a, -34a, -122, and let-7 are most studied, still only in experimental models. The miRs reported as most influencing/reflecting TNBC response to IR are miR-7, -27a, -155, -205, -211, and -221, whereas miR-21, -33a, -139-5p, and -210 are associated with TNBC patient outcome after RT.

CONCLUSION

miRs are emerging biomarkers and radiosensitizers in TNBC, worth further investigation. Dynamic assessment of circulating miRs could improve monitoring and TNBC RT efficacy, which are of particular interest in the neoadjuvant and the high-risk patients' settings.

MiR-125b-5p/TPD52 Axis Affects Proliferation, Migration and Invasion of Breast Cancer Cells

Aberrant gene expression caused by miRNAs disorders plays a relevant role in multiple steps of tumorigenesis. In this attempt, we studied the functional role of miR-125b-5p and TPD52 in breast cancer. TPD52 mRNA and miR-125b-5p levels were assessed via qRT-PCR, and TPD52 protein level was analyzed via western blot. By performing CCK-8, transwell invasion and wound healing assays, the phenotype changes in breast cancer cells were assessed. miR-125b-5p was proven as an upstream miRNA of TPD52 in breast cancer via TargetScan database, luciferase activity, and western blot. MiR-125b-5p was prominently decreased while TPD52 was dramatically increased in breast cancer cells. Functional assays exhibited that forced level of TPD52 facilitated cell proliferation, invasion and migration in breast cancer. In the end, the rescue assay proved that miR-125b-5p was a cancer repressor and modulated breast cancer progression by targeting TPD52. All above offer potential biomarkers for breast cancer treatment.

Role of non-coding RNAs in response of breast cancer to radiation therapy

Breast cancer ranks as the first common cancer with a high incidence rate and mortality among women. Radiation therapy is the main therapeutic method for breast cancer patients. However, radiation resistance of tumor cells can reduce the efficacy of treatment and lead to recurrence and mortality in patients. Non-coding RNA (ncRNAs) refers to a group of small RNA molecules that are not translated into protein, while they have the ability to modulate the translation of target mRNA. Several studies have reported the altered expression of ncRNAs in response to radiation in breast cancer. NcRNAs have been found to influence on radiation response of breast cancer by regulating various mechanisms, including DNA damage response, cell cycle regulation, cell death, inflammatory response, cancer stem cell and EGFR related pathways. This paper aimed to provide a summary of current findings on ncRNAs dysregulation after irradiation. We also present the function and mechanism of ncRNAs in modulating radiosensitivity or radioresistance of breast cancer cells.

The elevation of miR-185-5p alleviates high-fat diet-induced atherosclerosis and lipid accumulation in vivo and in vitro via SREBP2 activation

OBJECTIVE

SREBP2, a member of the SREBP family, is a primary regulator of lipid metabolism. In recent years, an increasing number of studies have suggested that miRNAs regulate lipid metabolism-related genes. It was speculated in this study that miRNAs may be implicated in the regulation of lipid accumulation in macrophages by SREBP2 protein.

METHODS AND RESULTS

GSE34812, GSE132651 and GSE28829 datasets comprised of atherosclerosis samples were downloaded to explore the gene expression profiles related to the miRNAs and SREBP2, and miR-185-5p was predicted to be a target of SREBP2. The GO annotations and KEGG pathway analysis were adopted for functional classification of differentially expressed genes, and lipid metabolic process was an enriched pathway in atherosclerosis. Besides, the effects of SREBP2 on increasing lipid accumulation were investigated in vivo using miR-185-5p mimic/apoE^-/- mice and miR-185-5p NC/apoE^-/- mice. All mice fed with a HFD suffered from atherosclerosis. Moreover, the effects of miR-185-5p on atherosclerotic plaque formation in mice were analyzed. An in vitro assay was also performed to determine the effect of miR-185-5p on ox-LDL-stimulated RAW 264.7 macrophages. Finally, miR-185-5p mimic was transfected into cultured macrophages. The results showed that the miR-185-5p elevation might regulate lipid accumulation in mice by targeting SREBP2. Furthermore, miR-185-5p mimic repressed the activation of SREBP1, SREBP2, LDLR, SCD-1, HMGCR as well as NLRP3, IL-1β, TNF-α in HFD fed mice or ox-LDL-stimulated macrophages.

CONCLUSIONS

our study demonstrated that miR-185-5p effectively alleviates atherosclerosis and lipid accumulation by regulating the miR-185-5p/SREBP2 axis.

PCAT6 May Be a Whistler and Checkpoint Target for Precision Therapy in Human Cancers

Simple Summary

Prostate cancer-associated transcript 6 (PCAT6), as a newly discovered carcinogenic long non-coding RNA (lncRNA), is abnormally expressed in multiple diseases. With the accumulation of studies on PCAT6, we have a deeper understanding of its biological functions and mechanisms. Therefore, in this review, the various molecular mechanisms by which PCAT6 promotes multiple tumorigenesis and progression are summarized and discussed. Furthermore, its potential diagnostic, prognostic, and immunotherapeutic values are also clarified.

Abstract

LncRNAs are involved in the occurrence and progressions of multiple cancers. Emerging evidence has shown that PCAT6, a newly discovered carcinogenic lncRNA, is abnormally elevated in various human malignant tumors. Until now, PCAT6 has been found to sponge various miRNAs to activate the signaling pathways, which further affects tumor cell proliferation, migration, invasion, cycle, apoptosis, radioresistance, and chemoresistance. Moreover, PCAT6 has been shown to exert biological functions beyond ceRNAs. In this review, we summarize the biological characteristics of PCAT6 in a variety of human malignancies and describe the biological mechanisms by which PCAT6 can facilitate tumor progression. Finally, we discuss its diagnostic and prognostic values and clinical applications in various human malignancies.

Long Noncoding RNA CRNDE Functions as an Oncogene to Facilitate Aggressive Behaviors of Nasopharyngeal Carcinoma Cells by Modulating miR-3163/TWIST1 Axis

Long noncoding RNA (lncRNA) CRNDE has been broadly implicated in many malignancies. The aim of this study was to explore the function and potential mechanisms of CRNDE in nasopharyngeal carcinoma (NPC). Here, we discovered that CRNDE level was increased in NPC tissues and cell lines. Additionally, elevated CRNDE positively correlated with large tumor size, advanced TNM stage, distant metastasis, EBV infection and worse prognosis. Furthermore, depletion of CRNDE significantly impaired the capacity of proliferation, migration and invasion in NPC cells. Mechanically, CRNDE could serve as a molecular sponge of miR-3163 to regulate the expression of TWIST1. Importantly, the inhibitory effects of CRNDE knockdown on cell proliferation and metastasis were blocked by silence of miR-3163 or restoration of TWIST1 expression. Overall, our data highlighted that CRNDE could promote NPC progression via altering miR-3163/TWIST1 axis, suggesting CRNDE as a potential prognostic biomarker and therapeutic target for NPC treatment.

Non-Coding RNAs Associated With Radioresistance in Triple-Negative Breast Cancer

The resistance that Triple-Negative Breast Cancer (TNBC), the most aggressive breast cancer subtype, develops against radiotherapy is a complex phenomenon involving several regulators of cell metabolism and gene expression; understanding it is the only way to overcome it. We focused this review on the contribution of the two leading classes of regulatory non-coding RNAs, microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), against ionizing radiation-based therapies. We found that these regulatory RNAs are mainly associated with DNA damage response, cell death, and cell cycle regulation, although they regulate other processes like cell signaling and metabolism. Several regulatory RNAs regulate multiple pathways simultaneously, such as miR-139-5p, the miR-15 family, and the lncRNA HOTAIR. On the other hand, proteins such as CHK1 and WEE1 are targeted by several regulatory RNAs simultaneously. Interestingly, the study of miRNA/lncRNA/mRNA regulation axes increases, opening new avenues for understanding radioresistance. Many of the miRNAs and lncRNAs that we reviewed here can be used as molecular markers or targeted by upcoming therapeutic options, undoubtedly contributing to a better prognosis for TNBC patients.

A Novel Prognostic Prediction Model for Colorectal Cancer Based on Nine Autophagy-Related Long Noncoding RNAs

Introduction

Colorectal cancer (CRC) is the most common gastrointestinal cancer and has a low overall survival rate. Tumor–node–metastasis staging alone is insufficient to predict patient prognosis. Autophagy and long noncoding RNAs play important roles in regulating the biological behavior of CRC. Therefore, establishing an autophagy-related lncRNA (ARlncRNA)-based bioinformatics model is important for predicting survival and facilitating clinical treatment.

Methods

CRC data were retrieved from The Cancer Genome Atlas. The database was randomly divided into train set and validation set; then, univariate and multivariate Cox regression analyses were performed to screen prognosis-related ARlncRNAs for prediction model construction. Interactive network and Sankey diagrams of ARlncRNAs and messenger RNAs were plotted. We analyzed the survival rate of high- and low-risk patients and plotted survival curves and determined whether the risk score was an independent predictor of CRC. Receiver operating characteristic curves were used to evaluate model sensitivity and specificity. Then, the expression level of lncRNA was detected by quantitative real-time polymerase chain reaction, and the location of lncRNA was observed by fluorescence in situ hybridization. Additionally, the protein expression was detected by Western blot.

Results

A prognostic prediction model of CRC was built based on nine ARlncRNAs (NKILA, LINC00174, AC008760.1, LINC02041, PCAT6, AC156455.1, LINC01503, LINC00957, and CD27-AS1). The 5-year overall survival rate was significantly lower in the high-risk group than in the low-risk group among train set, validation set, and all patients (all p < 0.001). The model had high sensitivity and accuracy in predicting the 1-year overall survival rate (area under the curve = 0.717). The prediction model risk score was an independent predictor of CRC. LINC00174 and NKILA were expressed in the nucleus and cytoplasm of normal colonic epithelial cell line NCM460 and colorectal cancer cell lines HT29. Additionally, LINC00174 and NKILA were overexpressed in HT29 compared with NCM460. After autophagy activation, LINCC00174 expression was significantly downregulated both in NCM460 and HT29, while NKILA expression was significantly increased.

Conclusion

The new ARlncRNA-based model predicts CRC patient prognosis and provides new research ideas regarding potential mechanisms regulating the biological behavior of CRC. ARlncRNAs may play important roles in personalized cancer treatment.

Screening and Bioinformatics Analysis of Competitive Endogenous RNA Regulatory Network --Related to Circular RNA in Breast Cancer

Purpose

Circular RNA as a competitive endogenous RNA (ceRNA) plays a significant role in the pathogenesis and progression of breast cancer. In this study, a circular RNA-related ceRNA regulatory network was constructed, which provides new biomarkers and therapeutic targets for the treatment of breast cancer. Materials and methods. The expression profile datasets (GSE101123, GSE143564, GSE50428) of circRNAs, miRNAs, and mRNAs were downloaded from the GEO database, and then differentially expressed RNAs (DEcircRNAs, DEmiRNAs, DEmRNAs) were obtained through the CSCD, TargetScan, miRDB, and miRTarBase databases. CircRNA-miRNA pairs and miRNA-mRNA pairs were constructed. Finally, a ceRNA regulatory network was established. Downstream analysis of the ceRNA network included GO, KEGG analysis, survival analysis, sub-network construction, the BCIP, and qRT-PCR verification.

Results

In total, 144 differentially expressed (DE) DEcircRNA, 221 DEmiRNA, and 1211 DEmRNA were obtained, and 96 circRNA-miRNA pairs and 139 miRNA-mRNA pairs were constructed by prediction. The ceRNA regulatory network (circRNA-miRNA-mRNA) was constructed, which included 42 circRNA, 36miRNA, and 78 mRNA. GO function annotation showed genes were mainly enriched in receptor activity activated by transforming growth factor beta (TGF-beta) and in the regulation of epithelial cell apoptosis. KEGG analysis showed genes were mainly enriched in the TGF-beta signaling, PI3K-Akt signaling, and Wnt signaling pathways. Four genes associated with survival and prognosis of breast cancer were obtained by survival analysis, the prognostic sub-network included 4 circRNA, 4 miRNA, and 4 mRNA. BCIP analysis and qRT-PCR verification confirmed that relative mRNA expression levels were consistent with those in the GEO database.

Conclusion

A circRNA-related ceRNA regulatory network was constructed for breast cancer in this study and key genes affecting pathogenesis and progression were identified. These findings may help better understand and further explore the molecular mechanisms that affect the progression and pathogenesis of breast cancer.

Long Noncoding RNAs Regulate the Radioresistance of Breast Cancer

Breast cancer (BRCA) has severely threatened women's health worldwide. Radiotherapy is a treatment for BRCA, which applies high doses of ionizing radiation to induce cancer cell death and reduce disease recurrence. Radioresistance is one of the most important elements that affect the therapeutic efficacy of radiotherapy. Long noncoding RNAs (lncRNAs) are suggested to dominate crucial roles in regulating the biological behavior of BRCA. Currently, some studies indicate that overexpression or inhibition of lncRNAs can greatly alter the radioresistance of BRCA. In this review, we summarized the knowledge on the classification and function of lncRNAs and the molecular mechanism of BRCA radioresistance, listed lncRNAs related to the BRCA radioresistance, highlighted their underlying mechanisms, and discussed the potential application of these lncRNAs in regulating BRCA radioresistance.

LncRNA GAS5 enhances radiosensitivity of hepatocellular carcinoma and restricts tumor growth and metastasis by miR-144-5p/ATF2

BACKGROUND

This study aimed to evaluate the biologic role of growth arrest-specific 5 (GAS5) in radiosensitivity of hepatocellular carcinoma (HCC).

METHODS

The levels of GAS5, miR-144-5p, and activating transcription factor 2 (ATF2) were quantified in HCC tissues and cell lines. RNA immunoprecipitation (RIP) and RNA pull-down assays were used to test the interaction between GAS5 and miR-144-5p. The regulatory relationship between miR-144-5p and ATF2 was identified by the dual-luciferase reporter (DLR) assay. A nude mouse model of HCC was induced to verify the effect of GAS5 on radiosensitivity of HCC in vivo.

RESULTS

Lower levels of GAS5 and ATF2, and higher levels of miR-144-5p, were found in radiation-resistant human HCC tissues and cell lines. Overexpression of ATF2 or GAS5 enhanced the radiosensitivity of HCC cell lines, while knockdown of ATF2 or GAS5 decreased the radiosensitivity. In addition, GAS5 acted as a miR-144-5p sponge, and miR-144-5p inversely regulated ATF2. Also, GAS5 mediated ATF2 levels through miR-144-5p, and increased the radiosensitivity of HCC by suppressing miR-144-5p both in vivo and in vitro.

CONCLUSION

Overexpression of GAS5 upregulates ATF2 through miR-144-5p and is able to enhance the radiosensitivity of HCC.

A review on the role of PCAT6 lncRNA in tumorigenesis

Prostate cancer-associated transcript 6 (PCAT6) is a long non-coding RNA (lncRNA) firstly identified in 2013 through an integrative genomic analysis of different cancer tissues. This oncogenic lncRNA has been found to regulate carcinogenesis process in different tissues, including breast, ovary, stomach, bladder, colon, pancreas and liver. The role of PCAT6 in sequestering certain microRNAs has been well established. For instance, miR-4723-5p, miR-185-5p, miR-143-3p, miR-30, miR-15a, miR-513a and miR-204, and miR-326 are among those being sequestered by PCAT6. Over-expression of PCAT6 has been associated with poor clinical outcomes in diverse types of cancers including ovarian, bladder, colorectal and pancreatic cancers. In the present review, we summarize the impact of PCAT6 in the development of diverse types of cancers, based on the results of functional studies in cell lines, experiments in xenograft models of cancers and expression studies in samples obtained from human subjects.

Multifaceted roles of long non-coding RNAs in triple-negative breast cancer: biology and clinical applications

Triple-negative breast cancer (TNBC) is a heterogeneous breast cancer subtype that lacks targeted therapy due to the absence of estrogen, progesterone, and HER2 receptors. Moreover, TNBC was shown to have a poor prognosis, since it involves aggressive phenotypes that confer significant hindrance to therapeutic treatments. Recent state-of-the-art sequencing technologies have shed light on several long non-coding RNAs (lncRNAs), previously thought to have no biological function and were considered as genomic junk. LncRNAs are involved in various physiological as well as pathological conditions, and play a key role in drug resistance, gene expression, and epigenetic regulation. This review mainly focuses on exploring the multifunctional roles of candidate lncRNAs, and their strong association with TNBC development. We also summarise various emerging research findings that establish novel paradigms of lncRNAs function as oncogenes and/or tumor suppressors in TNBC development, suggesting their role as prospective therapeutic targets.

Identification and Roles of miR-29b-1-3p and miR29a-3p-Regulated and Non-Regulated lncRNAs in Endocrine-Sensitive and Resistant Breast Cancer Cells

Despite improvements in the treatment of endocrine-resistant metastatic disease using combination therapies in patients with estrogen receptor α (ERα) primary tumors, the mechanisms underlying endocrine resistance remain to be elucidated. Non-coding RNAs (ncRNAs), including microRNAs (miRNA) and long non-coding RNAs (lncRNA), are targets and regulators of cell signaling pathways and their exosomal transport may contribute to metastasis. Previous studies have shown that a low expression of miR-29a-3p and miR-29b-3p is associated with lower overall breast cancer survival before 150 mos. Transient, modest overexpression of miR-29b1-3p or miR-29a-3p inhibited MCF-7 tamoxifen-sensitive and LCC9 tamoxifen-resistant cell proliferation. Here, we identify miR-29b-1/a-regulated and non-regulated differentially expressed lncRNAs in MCF-7 and LCC9 cells using next-generation RNA seq. More lncRNAs were miR-29b-1/a-regulated in LCC9 cells than in MCF-7 cells, including DANCR, GAS5, DSCAM-AS1, SNHG5, and CRND. We examined the roles of miR-29-regulated and differentially expressed lncRNAs in endocrine-resistant breast cancer, including putative and proven targets and expression patterns in survival analysis using the KM Plotter and TCGA databases. This study provides new insights into lncRNAs in endocrine-resistant breast cancer.

The Role of lncRNA PCAT6 in Cancers

Long non-coding RNA (lncRNA) PCAT6 is a member of the Prostate Cancer Associated Transcripts family of molecules. In this review, we focus on the latest studies involving PCAT6 in the diagnosis, treatment, and prognosis of malignant tumors of the digestive, respiratory, urinary, reproductive, motion, and nervous systems. PCAT6 was found to be highly expressed in gastric cancer, colon cancer, hepatocellular carcinoma, lung cancer, bladder cancer, ovarian cancer, breast cancer, cervical cancer, osteosarcoma, glioblastoma, and other tumors. PCAT6 can promote the development and progression of different types of malignant tumors through various mechanisms. Overall, these findings suggest that PCAT6 may play an increasingly vital role in the clinical assessment of these malignant tumors. It can function as an oncogene and may be used as a potential new prognostic biomarker of these tumors.

PCAT6 may be a new prognostic biomarker in various cancers: a meta-analysis and bioinformatics analysis

Background

LncRNA prostate cancer-associated transcript 6 (PCAT6) has been reported to be dysregulated in several cancers and is associated with tumor progression. Here, we have performed a meta-analysis to assess the general prognostic role of PCAT6 in malignancies.

Methods

Four public databases (Embase, Pubmed, Web of Science, Cochrane Library) were used to identify eligible studies, then data was extracted and associations between prognostic indicators and clinical characteristics were combined to estimate hazard ratio (HR) or odds ratio (OR) with a 95% confidence interval (CI). Publication bias was measured using the Begg's test, and the stability of the combined results was measured using sensitivity analysis. Subsequently, results were validated using Gene Expression Profiling Interactive Analysis (GEPIA) and the National Genomics Data Center (NGDC).

Results

Ten studies were considered eligible for inclusion. In total, 937 patients and eight types of cancer were included. Our results revealed that overexpression of PCAT6 was significantly associated with a shorter OS (HR = 1.82; 95% CI, [1.40, 2.38]; P < 0.0001) and progression-free survival (PFS) (HR = 1.66; 95% CI, [1.22, 2.25]; P < 0.0001) in cancer patients, and that PCAT6 overexpression was significantly associated with individual tumor clinicopathological parameters, including TNM stage (OR = 0.29; 95% CI, [0.09, 0.94]; P = 0.04), gender (OR = 1.84; 95% CI, [1.31, 2.59]; P = 0.0005), and whether the tumor was metastatic (OR = 5.02; 95% CI, [1.36, 18.57]; P = 0.02). However, PCAT6 overexpression was not correlated with patient age and tumor differentiation. PCAT6 expression was significantly up-regulated in four types of cancer, which was validated using the GEPIA cohort. Combining OS and disease-free survival (DFS) of these four types of cancer revealed a shorter OS and DFS in patients with PCAT6 overexpression. PCAT6 expression in various types of cancer was also validated in NGDC. A total of eight cancers were analyzed and PCAT6 was highly expressed in all eight cancers. Further functional predictions suggest that PCAT6 is correlated with tumor prognosis, and that PCAT6 may be useful as a new tumor-specific marker.

Conclusions

LncRNA PCAT6 is highly expressed in multiple cancer types and its upregulation was significantly associated with patient prognosis and poorer clinical features, thereby suggesting that PCAT6 may be a novel prognostic factor in multiple cancer types.

Long non-coding RNA PCAT6 regulates bladder cancer progression via the microRNA-143-3p/PDIA6 axis

Although long non-coding (lnc)RNAs have been reported to be involved in the pathological development of bladder cancer, the functions of lncRNA prostate cancer-associated transcript 6 (PCAT6) and its underlying mechanism of action in bladder cancer remain unknown. The present study aimed to investigate the effect of PCAT6 in bladder cancer progression and explore its potential application as a novel treatment target. The expression of PCAT6 and miR-143-3p in bladder cancer tissues, adjacent normal tissues and cell lines was measured using reverse transcription-quantitative PCR. Fluorescence in situ hybridization assay was used to detect the subcellular localization of PCAT6. MTT, EdU, Transwell and wound healing assays were conducted to assess the biological function of PCAT6 on cell proliferation, migration and invasion. Putative binding sites between miR-143-3p and PCAT6 or PDIA6 were predicted using starBase, Lncbase and TargetScan analyzes. Dual-luciferase reporter assay was also used to confirm the potential binding between PCAT6 and miR-143-3p. RNA immunoprecipitation assay was performed to verify the possible interaction between PCAT6 and miR-143-3p. Western blotting was used to measure the expression of PDIA6. The results demonstrated that the expression levels of PCAT6 were upregulated in bladder cancer tissues relative to those in adjacent normal bladder tissues. Knockdown of PCAT6 served a role in suppressing the proliferation, migration and invasion of T24T and EJ bladder cancer cells. PCAT6 knockdown contributed to a reduction of PDIA6 expression at the mRNA and protein levels compared with that in negative control-transfected cells, whilst the miR-143-3p inhibitor partially mitigated this reduction effect. In addition, rescue experiments revealed that the miR-143-3p inhibitors reversed the effects of PCAT6 silencing on the malignant phenotypes of bladder cancer. Collectively, the results of the present study demonstrated that PCAT6 may serve an oncogenic role in bladder cancer via the miR-143-3p/PDIA6 axis. These results may provide a potential therapeutic target for the treatment of bladder cancer.

Enzalutamide-Induced Upregulation of PCAT6 Promotes Prostate Cancer Neuroendocrine Differentiation by Regulating miR-326/HNRNPA2B1 Axis

Our previous studies have demonstrated that Enzalutamide-induced upregulation of long non-coding RNA p21 (lncRNA-p21) facilitates prostate cancer (PCa) neuroendocrine differentiation (NED). Given the important role of lncRNAs in PCa pathogenesis, and given that lots of lncRNAs are dys-regulated in neuroendocrine PCa (NEPC) patients, we next explored the biological function and underlying mechanism of lncRNA-PCAT6 (PCAT6) in mediating Enzalutamide-induced NED. The level of PCAT6 in Enzalutamide-treated PCa cells and NEPC samples were assessed using quantitative RT-PCR (qPCR). The effect of PCAT6 on PCa cell proliferation, invasion, and NED was evaluated through CCK-8, transwell, qPCR, western blot analysis, Xenograft mouse model, and in vivo lung metastasis model. We found that PCAT6 was highly expressed in NE-like cells (PC3, DU145, and NCI-H660) compared with androgen-sensitive LNCaP cells. PCAT6 was also highly expressed in NEPC tissues. Enzalutamide treatment resulted in a significant increase of PCAT6 level in a dose- and time-dependent fashion. Functionally, PCAT6 overexpression promoted NED of C4-2 cells, as evidenced by an increased expression of NE markers (NSE, ChgA, and SYP), whereas PCAT6 knockdown in NCI-H661 cells repressed NED. Furthermore, PCAT6 overexpression promoted PCa cell proliferation and invasion in vitro and in vivo. Mechanistically, PCAT6 functioned as competing endogenous (ce) RNA via absorbing miR-326, thus resulting in a de-suppression of Hnrnpa2b1 target gene. The current results demonstrate that PCAT6 acted as a tumor activator in PCa progression by sponging miR-326 and increasing Hnrnpa2b1 expression and that the PCAT6/miR-326/Hnrnpa2b1 signaling might be a new therapeutic target for PCa.

Long noncoding RNAs in triple-negative breast cancer: A new frontier in the regulation of tumorigenesis

In recent years, triple-negative breast cancer (TNBC) has emerged as the most aggressive subtype of breast cancer and is usually associated with increased mortality worldwide. The severity of TNBC is primarily observed in younger women, with cases ranging from approximately 12%-24% of all breast cancer cases. The existing hormonal therapies offer limited clinical solutions in completely circumventing the TNBC, with chemoresistance and tumor recurrences being the common hurdles in the path of TNBC treatment. Accumulating evidence has correlated the dysregulation of long noncoding RNAs (lncRNAs) with increased cell proliferation, invasion, migration, tumor growth, chemoresistance, and decreased apoptosis in TNBC. Various clinical studies have revealed that aberrant expression of lncRNAs in TNBC tissues is associated with poor prognosis, lower overall survival, and disease-free survival. Due to these specific characteristics, lncRNAs have emerged as novel diagnostic and prognostic biomarkers for TNBC treatment. However, the underlying mechanism through which lncRNAs perform their actions remains unclear, and extensive research is being carried out to reveal it. Therefore, understanding of mechanisms regulating the modulation of lncRNAs will be a substantial breakthrough in effective treatment therapies for TNBC. This review highlights the association of several lncRNAs in TNBC progression and treatment, along with their possible functions and mechanisms.

m6 A modification of lncRNA PCAT6 promotes bone metastasis in prostate cancer through IGF2BP2-mediated IGF1R mRNA stabilization

BACKGROUND

Bone metastasis is the leading cause of tumor-related death in prostate cancer (PCa) patients. Long noncoding RNAs (lncRNAs) have been well documented to be involved in the progression of multiple cancers. Nevertheless, the role of lncRNAs in PCa bone metastasis remains largely unclear.

METHODS

The expression of prostate cancer-associated transcripts was analyzed in published datasets and further verified in clinical samples and cell lines by RT-qPCR and in situ hybridization assays. Colony formation assay, MTT assay, cell cycle analysis, EdU assay, Transwell migration and invasion assays, wound healing assay, and in vivo experiments were carried out to investigate the function of prostate cancer-associated transcript 6 (PCAT6) in bone metastasis and tumor growth of PCa. Bioinformatic analysis, RNA pull-down, and RIP assays were conducted to identify the proteins binding to PCAT6 and the potential targets of PCAT6. The therapeutic potential of targeting PCAT6 by antisense oligonucleotides (ASO) was further explored in vivo.

RESULTS

PCAT6 was upregulated in PCa tissues with bone metastasis and increased PCAT6 expression predicted poor prognosis in PCa patients. Functional experiments found that PCAT6 knockdown significantly inhibited PCa cell invasion, migration, and proliferation in vitro, as well as bone metastasis and tumor growth in vivo. Mechanistically, METTL3-mediated m6 A modification contributed to PCAT6 upregulation in an IGF2BP2-dependent manner. Furthermore, PCAT6 upregulated IGF1R expression by enhancing IGF1R mRNA stability through the PCAT6/IGF2BP2/IGF1R RNA-protein three-dimensional complex. Importantly, PCAT6 inhibition by ASO in vivo showed therapeutic potential against bone metastasis in PCa. Finally, the clinical correlation of METTL3, IGF2BP2, IGF1R, and PCAT6 was further demonstrated in PCa tissues and cells.

CONCLUSIONS

Our study uncovers a novel molecular mechanism by which the m6 A-induced PCAT6/IGF2BP2/IGF1R axis promotes PCa bone metastasis and tumor growth, suggesting that PCAT6 may serve as a promising prognostic marker and therapeutic target against bone-metastatic PCa.

Long non-coding DANCR targets miR-185-5p to upregulate LIM and SH3 protein 1 promoting prostate cancer via the FAK/PI3K/AKT/GSK3β/snail pathway

BACKGROUND

Long non-coding RNA differentiation antagonizing non-protein coding RNA (DANCR) acts as an oncogene in different cancers, although its roles in prostate cancer are not fully reported. We aimed to explore its mechanism in facilitating the malignancy of prostate cancer.

METHODS

The expression of DANCR, microRNA (miR)-185-5p and LIM and SH3 protein 1 (LASP1) in 40 pairs of prostate cancer tissues and normal tissues, five prostate cancer cell lines and one epithelial cell line was assessed by a quantitative real-time polymerase chain reaction, western blotting and immunohistochemistry, respectively. In transfected PC3 and C4-2 cells, cell proliferation, migration, invasion, cell cycle distribution and epithelial-mesenchymal transition (EMT) protein expression were tested via cell counting kit-8, wound healing, transwell, flow cytometry and western blot assays, respectively. The interactions between DANCR, miR-185-5p and LASP1 were verified by a dual-luciferase reporter assay. Rescue experiments were conducted to determine the roles of DANCR on the malignant properties of PC3 and C4-2 cells. The involvement of the signaling pathway was examined using a p-FAK inhibitor.

RESULTS

DANCR and LASP1 expression was enhanced, whereas miR-185-5p expression was diminished in prostate cancer tissues and cell lines. Knockdown of DANCR suppressed cell proliferation, migration, invasion, G1-S transition and expression of EMT proteins of the transfected PC3 and C4-2 cells. DANCR sponged miR-185-5p to upregulate LASP1 expression. DANCR-miR-185-5p-LASP1 axis activates the FAK/PI3K/AKT/GSK3β/Snail pathway to promote the malignant properties of PC3 and C4-2 cells.

CONCLUSIONS

These findings suggest that DANCR exerts oncogenic roles in prostate cancer via the miR-185-5p/LASP1 axis activating the FAK/PI3K/AKT/GSK3β/Snail pathway. It can be a potential biomarker in the diagnosis and monitoring of prostate cancer.

lncRNA PCAT6 facilitates cell proliferation and invasion via regulating the miR-326/hnRNPA2B1 axis in liver cancer

Liver cancer is one of the most common malignant human tumors with the highest morbidity and mortality rates of all cancer types in China. Evidence suggests that long non-coding RNA prostate cancer-associated transcript 6 (PCAT6) plays an essential role in tumor progression. However, the roles and mechanism of PCAT6 in liver cancer remain unclear. The present study showed that the expression of PCAT6 and heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) was upregulated in liver cancer tissues compared with non-cancerous tissues and were associated with poor overall survival time, whereas microRNA (miR)-326 expression was downregulated. Moreover, knockdown of PCAT6 significantly inhibited the proliferation and invasion of liver cancer cells in vitro and in vivo. A dual-luciferase reporter gene assay demonstrated that PCAT6 could bind to miR-326 and that hnRNPA2B1 was a direct target gene of miR-326. Mechanistically, silenced PCAT6 suppressed the malignant phenotype of liver cancer cells through upregulating the inhibitory effect of miR-326 on hnRNPA2B1 expression. Taken together, these data demonstrated that knockdown of PCAT6 inhibited liver cancer progression through regulation of the miR-326/hnRNPA2B1 axis, suggesting that PCAT6 functions as an oncogene and may be a useful biomarker for the future diagnosis and treatment of liver cancer.

Promising role of long non-coding RNA PCAT6 in malignancies

Long non-coding RNAs (lncRNAs), a newly identified class of non-coding RNA (ncRNA), are defined as RNA molecules at least 200 nucleotides in length that are not translated into proteins. LncRNAs contribute to a wide range of biological processes and are master regulators of disease occurrence, development, and response to therapy in human malignancies. The lncRNA prostate cancer‑associated transcript 6 (PCAT6) is upregulated in various human malignancies, including lung cancer, hepatocellular carcinoma, cervical cancer, osteosarcoma, glioblastoma, colorectal cancer, breast cancer, gastric cancer, gastrointestinal stromal tumors, and pancreatic ductal adenocarcinoma. High expression of PCAT6 is closely correlated with aggressive clinicopathological characteristics and poor prognosis in cancer patients, suggesting it is an oncogenic lncRNA. PCAT6 overexpression also facilitates cell proliferation, invasion, and migration while attenuating apoptosis, indicating that it might serve as a new prognostic biomarker and therapeutic target for malignancies. Here, we discuss the molecular mechanisms, regulatory functions, and potential clinical applications of PCAT6 in cancer.

The long non-coding RNA landscape in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a type of breast cancer that has a higher risk of distant recurrence and metastasis, leading to a relatively aggressive biological behaviour and poor outcome. So far, the clinical management of TNBC is challenging because of its heterogeneity and paucity of specific targeted therapy. Recently, various studies have identified a lot of differently expressed long non-coding RNAs (lncRNAs) in TNBC. Those lncRNAs have been reported to play important roles in the multistep process of TNBC tumorigenesis. Here, we review the biological characteristics of lncRNAs, and present the current state of knowledge concerning the expression, function and regulation of lncRNAs in TNBC. Accumulating studies explored the potential lncRNAs-based therapeutics in TNBC, including the techniques of genetic modification using antisense oligonucleotides, locked nucleic acid and RNA nanotechnology. In current review, we also discuss the future prospects of studies about lncRNAs in TNBC and development of lncRNA-based strategies for clinical TNBC patients.

Single-cell long noncoding RNA (lncRNA) transcriptome implicates MALAT1 in triple-negative breast cancer (TNBC) resistance to neoadjuvant chemotherapy

Cumulative evidence suggests added benefit for neoadjuvant chemotherapy (NAC) in a subset of triple-negative breast cancer (TNBC) patients. Herein we identified the long noncoding RNA (lncRNA) transcriptional landscape associated with TNBC resistance to NAC, employing 1758 single cells from three extinction and three persistence TNBC patients. Using Iterative Clustering and Guide-gene Selection (ICGS) and uniform manifold approximation and projection (UMAP) dimensionality reduction analysis, we observed single cells derived from each patient to largely cluster together. Comparing the lncRNA transcriptome from single cells through the course of NAC treatment revealed minimal overlap based on lncRNA transcriptome, suggesting substantial effects of NAC on lncRNA transcription. The differential analysis revealed upregulation of 202 and downregulation of 19 lncRNAs in the persistence group, including upregulation of five different transcripts encoding for the MALAT1 lncRNA. CRISPR/Cas9-mediated MALAT1 promoter deletion in BT-549 TNBC model enhanced sensitivity to paclitaxel and doxorubicin, suggesting a role for MALAT1 in conferring resistance. Mechanistically, whole transcriptome analysis of MALAT1-KO cells revealed multiple affected mechanistic networks as well as oxidative phosphorylation canonical and angiogenesis functional category. Interestingly, lncRNA profiling of MALAT1-depleted TNBC also revealed a number of altered lncRNAs in response to MALAT1 deletion, suggesting a reciprocal relationship between MALAT1 and a number of lncRNAs, including NEAT1, USP3-AS1, and LINC-PINT, in TNBC. Elevated expression of MALAT1, USP3-AS1, and LINC-PINT correlated with worse clinical outcomes in BC patients. Our data revealed the lncRNA transactional portrait and highlighted a complex regulatory network orchestrated by MALAT1 in the context of TNBC resistance to NAC therapy.

Emerging role of non-coding RNAs in response of cancer cells to radiotherapy

Radiotherapy is an effective method for treatment of a large proportion of human cancers. Yet, the efficacy of this method is precluded by the induction of radioresistance in tumor cells and the radiation-associated injury of normal cells surrounding the field of radiation. These restrictions necessitate the introduction of modalities for either radiosensitization of cancer cells or protection of normal cells against adverse effects of radiation. Non-coding RNAs (ncRNAs) have essential roles in the determination of radiosensitivity. Moreover, ncRNAs can modulate radiation-induced side effects in normal cells. Several microRNAs (miRNAs) such as miR-620, miR-21 and miR-96-5p confer radioresistance, while other miRNAs including miR-340/ 429 confer radiosensitivity. The expression levels of a number of miRNAs are associated with radiation-induced complications such as lung fibrosis or oral mucositis. The expression patterns of several long non-coding RNAs (lncRNAs) such as MALAT1, LINC00630, HOTAIR, UCA1 and TINCR are associated with response to radiotherapy. Taken together, lncRNAs and miRNAs contribute both in modulation of response of cancer cells to radiotherapy and in protection of normal cells from the associated side effects. The current review provides an overview of the roles of these transcripts in these aspects.

LncRNA ADAMTS9-AS1 Restrains the Aggressive Traits of Breast Carcinoma Cells via Sponging miR-513a-5p

Purpose

Long noncoding RNAs (lncRNAs) exert important functions in the progression of cancers. Currently, we aim to investigate the potential roles of lncRNA ADAM Metallopeptidase with Thrombospondin Type 1 Motif 9 Antisense RNA 1 (ADAMTS9-AS1) in breast carcinoma.

Materials and Methods

The expressions of ADAMTS9-AS1 and miR-513a-5p in breast carcinoma tissues and cell lines were detected using qRT-PCR. Cell Counting Kit-8 (CCK-8) and transwell assays were used to assess the viability and invasive ability of breast cancer cells. The direct interaction between ADAMTS9-AS1 and miR-513a-5p was predicted using bioinformatics tools. The target of miR-513a-5p, ZFP36 Ring Finger Protein (ZFP36) was validated by luciferase assay. The expression of ZFP36 was measured using Western blot assay. Breast cancer MDA-MB-231 cells growth in vivo was evaluated using xenograft tumor assay.

Results

ADAMTS9-AS1 was downregulated in breast cancer tissues as well as cell lines. Upregulation of ADAMTS9-AS1 suppressed the growth and invasiveness of breast carcinoma cells in vitro as well as inhibiting cellgrowth in vivo. Furthermore, ZFP36 was manifested as the target gene of miR-513a-5p and negatively modulated by ADAMTS9-AS1. In addition, overexpression of ADAMTS9-AS1 neutralized the promoting impact of miR-513a-5p on the aggressiveness of breast cancer cells.

Conclusion

In conclusion, lncRNA ADAMTS9-AS1 inhibited the aggressive phenotypes of breast carcinoma cells via sponging miR-513a-5p and regulating ZFP36.

Non-Coding RNAs in Cancer Radiosensitivity: MicroRNAs and lncRNAs as Regulators of Radiation-Induced Signaling Pathways

Radiotherapy is a cancer treatment that applies high doses of ionizing radiation to induce cell death, mainly by triggering DNA double-strand breaks. The outcome of radiotherapy greatly depends on radiosensitivity of cancer cells, which is determined by multiple proteins and cellular processes. In this review, we summarize current knowledge on the role of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), in determining the response to radiation. Non-coding RNAs modulate ionizing radiation response by targeting key signaling pathways, including DNA damage repair, apoptosis, glycolysis, cell cycle arrest, and autophagy. Additionally, we indicate miRNAs and lncRNAs that upon overexpression or inhibition alter cellular radiosensitivity. Current data indicate the potential of using specific non-coding RNAs as modulators of cellular radiosensitivity to improve outcome of radiotherapy.