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LncRNA HOTAIR enhances breast cancer radioresistance through facilitating HSPA1A expression via sequestering miR-449b-5p.

ABSTRACT: BACKGROUND:Breast cancer (BRCA) is the leading cause of cancer-related death in women worldwide. Pre- and postoperative radiotherapy play a pivotal role in BRCA treatment but its efficacy remains limited and plagued by the emergence of radiation resistance, which aggravates patient prognosis. The long noncoding RNA (lncRNA)-implicated mechanisms underlying radiation resistance are rarely reported. The aim of this study was to determine whether lncRNA HOX transcript antisense RNA (HOTAIR) modulated the radiosensitivity of breast cancer through HSPA1A. METHODS:A Gammacell 40 Exactor was used for irradiation treatment. Bioinformatic tools and luciferase reporter assay were adopted to explore gene expression profile and demonstrate the interactions between lncRNA, miRNA and target mRNA 3'-untranslated region (3'-UTR). The expression levels of certain genes were determined by real-time PCR and western-blot analyses. in vitro and in vivo functional assays were conducted by cell viability and tumorigenicity assays. RESULTS:The levels of oncogenic lncRNA HOTAIR were positively correlated with the malignancy of BRCA but reversely correlated with the radiosensitivity of breast cancer cells. Moreover, the expression levels of HOTAIR were positively associated with those of heat shock protein family A (Hsp70) member 1A (HSPA1A) in clinical BRCA tissues and HOTAIR upregulated HSPA1A at the mRNA and protein levels in irradiated BRCA cells. Mechanistically, miR-449b-5p restrained HSPA1A expression through targeting the 3'-UTR of HSPA1A mRNA, whereas HOTAIR acted as a competing sponge to sequester miR-449b-5p and thereby relieved the miR-449b-5p-mediated HSPA1A repression. Functionally, HOTAIR conferred decreased radiosensitivity on BRCA cells, while miR-449b-5p overexpression or HSPA1A knockdown abrogated the HOTAIR-enhanced BRCA growth under the irradiation exposure both in vitro and in vivo. CONCLUSIONS:LncRNA HOTAIR facilitates the expression of HSPA1A by sequestering miR-449b-5p post-transcriptionally and thereby endows BRCA with radiation resistance. KEY POINTS:Therapeutically, HOTAIR and HSPA1A may be employed as potential targets for BRCA radiotherapy. Our findings shed new light into the mechanism by which lncRNAs modulate the radiosensitivity of tumors.

SUBMITTER: Zhang S

PROVIDER: S-EPMC7327697 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature

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LncRNA HOTAIR enhances breast cancer radioresistance through facilitating HSPA1A expression via sequestering miR-449b-5p.

Zhang Shuqin S Wang Bin B Xiao Huiwen H Dong Jiali J Li Yuan Y Zhu Changchun C Jin Yuxiao Y Li Hang H Cui Ming M Fan Saijun S

Thoracic cancer 20200506 7

<h4>Background</h4>Breast cancer (BRCA) is the leading cause of cancer-related death in women worldwide. Pre- and postoperative radiotherapy play a pivotal role in BRCA treatment but its efficacy remains limited and plagued by the emergence of radiation resistance, which aggravates patient prognosis. The long noncoding RNA (lncRNA)-implicated mechanisms underlying radiation resistance are rarely reported. The aim of this study was to determine whether lncRNA HOX transcript antisense RNA (HOTAIR) ...[more]

PMID: 32374522

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Project description:BackgroundLung cancer, especially lung squamous cell carcinoma (LUSC), is one of the most common malignant tumors worldwide. Currently, radiosensitization research is a vital direction for the improvement of LUSC therapy. Long non-coding RNAs (lncRNAs) can be novel biomarkers due to their multiple functions in cancers. However, the function and mechanism of lncRNA KCNQ1OT1 in the radioresistance of LUSC remain to be elucidated.MethodsThe clonogenic assay was employed to determine the radioresistance of SK-MES-1R and NCI-H226R cells. Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot were conducted for the detection of gene expression. Cell proliferation was determined by the methyl thiazolyl tetrazolium (MTT) assay, colony formation assay, and 5-ethynyl-2'-deoxyuridine (EdU) staining, and cell apoptosis was assessed by flow cytometry. The relationships between genes were also evaluated by applying the luciferase reporter and radioimmunoprecipitation (RIP) assays.ResultsRadioresistant LUSC cells (SK-MES-1R and NCI-H226R) had strong resistance to X-ray irradiation, and lncRNA KCNQ1OT1 was highly expressed in SK-MES-1R and NCI-H226R cells. Moreover, knockdown of lncRNA KCNQ1OT1 prominently suppressed proliferation, attenuated radioresistance, and accelerated the apoptosis of SK-MES-1R and NCI-H226R cells. More importantly, we verified that miR-491-5p was a regulatory target of lncRNA KCNQ1OT1, and Xenopus kinesin-like protein 2 (TPX2) and RING finger protein 2 (RNF2) were the target genes of miR-491-5p. The rescue experiment results also demonstrated that miR-491-5p was involved in the inhibition of cell proliferation and the downregulation of TPX2 and RNF2 expression mediated by lncRNA KCNQ1OT1 knockdown in SK-MES-1R and NCI-H226R cells.ConclusionsLncRNA KCNQ1OT1 was associated with the radioresistance of radioresistant LUSC cells, and the lncRNA KCNQ1OT1/miR-491-5p/TPX2-RNF2 axis might be used as a therapeutic target to enhance the radiosensitivity of radioresistant LUSC cells.

Project description:BackgroundLong non-coding ribonucleic acids (lncRNAs) are believed to play crucial roles in cardiovascular diseases; however, details of the underlying mechanisms by which this occurs remain unclear.MethodsA mouse heart failure (HF) model was established using isoproterenol (ISO), and confirmed by immunostaining and echocardiography. RNA-sequencing was performed to screen the differential lncRNA expression profiles and heart failure relative lncRNA (HFRL) was selected as the target which was validated by quantitative real-time polymerase chain reaction (qRT-PCR). In HL-1 cells, the cardiac function, inflammatory, and fibrosis-related genes expression changes were examined by qRT-PCR after silencing of HFRL by lentivirus. Meanwhile, Cell Counting Kit-8 (CCK-8) assays were used to detect the effects of HFRL on the cell proliferation and viability. Reactive oxygen species (ROS) assays were also used to explore the role of HFRL in oxidative damage. Next, bioinformatics analysis was conducted to predict the potential binding microRNAs (mmu-miR-149-5p) to HFRL, which was confirmed by RNA-pulldown assays. The target gene of miR-149-5p was also predicted and further validated by Dual-luciferase reporter assays, qRT-PCR, and western blot. To investigate the synergistic regulatory effect of HFRL and miR-149-5p, HL-1 cells were infected with the lentivirus of HFRL with or without simultaneous knockdown of miR-149-5p. Then, qRT-PCR and western blot were used to examine cardiac function, inflammatory, and fibrosis-related gene expression changes, respectively. In HL-1 cells, CCK-8 assays were performed to detect the proliferation and viability. ROS assays were used to explore the oxidative damage.ResultsThe administration of ISO induced mice fibrosis, inflammation, and HF. The in-vitro results showed that knockdown of HFRL suppressed cardiomyocyte proliferation and viability, attenuated inflammatory, cardiac function, and fibrosis-related gene expression, and promoted oxidative damage. HFRL was found to bind to mmu-miR-149-5p and inversely target the 3'-untranscripted region of the collagen 22A1 gene. Thus, HFRL affected cardiomyocyte inflammation, proliferation, viability, oxidative damage, and pro-fibrotic function via sequestration to miR-149-5p.ConclusionsThe HFRL/miR-149-5p axis plays an important role in regulating cardiac inflammation, proliferation, and fibrosis via a synergistic effect, which suggests that HFRL might be a novel target for HF.

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LncRNA HOTAIR enhances breast cancer radioresistance through facilitating HSPA1A expression via sequestering miR-449b-5p.

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LncRNA HOTAIR enhances breast cancer radioresistance through facilitating HSPA1A expression via sequestering miR-449b-5p.

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