Identification of a Novel Pathway in BCR/ABL Signal Transduction Involving Akt-Independent Activation of PLC-gamma/mTOR/p70-S6K.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2120-2120
Author(s):  
Boyka Markova ◽  
Christoph Huber ◽  
Thomas Fischer
Keyword(s):  
Signaling Pathway ◽  
Cell Lines ◽  
Alternative Pathway ◽  
Therapeutic Targets ◽  
Specific Inhibitor ◽  
Physical Interaction ◽  
Alternative Mechanism ◽  
Imatinib Treatment ◽  
Short Term Treatment ◽  
P70 S6k

Abstract In BCR/ABL positive CML, defining new, additional therapeutic targets in the pathways, activated by BCR/ABL is critical for the development of new treatment strategies, especially for patients resistant or refractory to Imatinib. While studying the involvement of PI3K/Akt/mTOR signaling pathway in the development of such resistance we have uncovered the existence of additional, Akt-independent mechanism of activation of mTOR/p70-S6 Kinase pathway. Short term treatment with Imatinib (1μM, 4 hours) of the BCR/ABL-positive cell lines LAMA84, AR320, KCL22, K562, Ba/F3-BCR/ABL caused downregulation of p70-S6K phosphorylation and of S6 ribosomal protein phosphorylation without decreasing phosphorylation levels of Akt, as detected by Western blotting using the respective phosphorylation-specific antibodies p-p70-S6K (Thr389), p-S6 (Ser240/244) and p-Akt (Ser473). Inhibition of Akt by the specific inhibitor SH-6 (10μM, 4 hours treatment) did not affect the phosphorylation of p70-S6K and S6. These results were consistent in all analyzed cell lines, and led us to consider alternative mechanism for mTOR/p70-S6K pathway activation. One such mechanism, recently described in FGF9 signaling is a Phospholipase-C-gamma (PLCγ)-controlled Calcium signaling pathway (Wing et al., JBC, 19937–47, 2005), involving Ca/Calmodulin (CaM) and Ca/Calmodulin-dependent Kinase (CaM-K). In all BCR/ABL+ cell lines analyzed we could detect strong PLCγ activation (examined by p-PLCγ-Tyr783 antibody), which was effectively suppressed by Imatinib treatment (1μM, 4 hours). Incubation of the cells for 30 minutes with 10μM U73122, a specific PLC inhibitor, in contrast to the inactive analog U73343, significantly blocked p70-S6K and S6 phosphorylation. The actual mechanism of the Akt-independent mTOR/p70-S6K activation by BCR/ABL is not yet entirely understood. In general, PLCγ activation in turn leads to the activation of different PKC isoform and increase in Ca-dependent signaling. By employing inhibitors of Calmodulin (W7), CaM-K (KN-93) and the PKC inhibitor PKC-412 we are currently studying the participation of these molecules in the pathway. The function of PLCγ/mTOR/p70-S6K pathway for the BCR/ABL driven cells is also analyzed in proliferation (MTT) and apoptosis assays where cells are treated with Imatinib alone or in combination with U73122. Knocking down of PLCγ and other involved molecules is another approach which we will utilize to better understand the necessity/sufficiency of PLCγ for full activation of mTOR/p70-S6K pathway in the BCR/ABL+ cells, as well as the (physical) interaction of PLCγ and BCR/ABL. In summary, we demonstrate the existence of additional, Akt-independent, PLCγ-dependent mode of activation of mTOR/p70-S6K which operates in BCR/ABL-positive cells. This alternative pathway may prove novel therapeutic targets for CML treatment.

scholarly journals Super-Enhancer Profiling Identifies Novel Oncogenes and Therapeutic Targets in Multiple Myeloma

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 362-362
Author(s):  
Jianbiao Zhou ◽  
Yunlu Jia ◽  
Tze King Tan ◽  
Tae-Hoon Chung ◽  
Takaomi Sanda ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Lines ◽  
Plasma Cell ◽  
Conflicts Of Interest ◽  
Cell Cancer ◽  
Ectopic Expression ◽  
Therapeutic Targets ◽  
Physical Interaction ◽  
Rna Seq ◽  
Normal Plasma

Background: Multiple myeloma (MM) is an aggressive neoplastic plasma cell cancer characterized by diversely cytogenetic abnormalities. MM can be divided into subtypes with immunoglobulin heavy chain (IGH) gene translocations involving CCND1-3, FGFR3/MMSET, MAFs and hyperdiploid myeloma containing trisomies of several odd numbered chromosomes 3, 5, 7, 9, 11, 15, 19, and 21. Although several new drugs have been introduced into clinic, treatment for MM patients remains challenge and refractory/resistant to therapy is often seen. Thus, a better understanding of the molecular pathogenesis of MM can lead to generate new prognostic classification and identify new therapeutic targets. Super-enhancers (SEs) are defined as large clusters of cis-acting enhancers, marked by high level bindings of acetylation of histone H3 lysine 27 (H3K27ac) and mediator complex. SEs have been shown to control genes for maintaining cellular identity and also key tumor drivers in various malignancies. Methods: H3K27Ac ChIP-seq and RNA-seq were performed on primary MM patient samples, MM cell lines. Normal plasma cells and lymphoma cell lines were served as controls. We systematically compared SEs and their associated genes of normal and cancerous tissue. THZ1, a CDK7 inhibitor, was used to efficiently down-regulate SE-associated genes. Combinatory analysis of THZ1-sensitive and SE-associated gene revealed a number of promising MM oncogenes. CRISPR/Cas9 technology and ectopic expression experiments in conjunction with cellular functional assays were performed to determine the effects of candidate SE-genes on MM cells. Circularized chromatin conformation capture followed by sequencing (4C-seq) was applied to explore the direct contact of SE and promoter. Results: SE analysis uncovered some cell lineage-specific transcription factors (TFs) and known oncogenes in MM. Several key TFs, including IRF4, PRDM1, MYC and XBP1, were identified in most MM samples, confirming the origin of MM cells. These data reinforce the concept that SE establishment is a key component of MM biology. The acquisition of SEs around oncogene drivers is widely observed during tumorigenesis. ST3GAL6 and ADM were two known oncogenic drivers in myeloma cells, which were associated with super-enhancers in all MM samples but not in normal plasma cell and lymphoma cells. We also found SE constituents for multiple subtype-specific key oncogenes such as CCND1 in t(11;14) cells, C-MAF in t(14;16) cells, and NSD2 and FGFR3 in t(4;14) cells. Furthermore, THZ1 showed prominent anti-neoplastic effect against MM cells. SE-associated genes were more sensitive to THZ1 compared with those genes associated with typical enhancers (TEs). By overlapping THZ1-sensitve gene with SE-associated genes, we identified a number of novel MM oncogenes, including MAGI2, EDEM3, HJURP, LAMP5, MBD1 and UCK2 as a potential druggable kinase. The expression level of MAGI2 and HJURP confers poor prognosis in several MM datasets. MAGI2 silencing in MM cells decreased cell proliferation and induced apoptosis. qRT-PCR and Western blot analysis confirmed the overexpression of HJURP in t(4;14) cells relative to non-t(4;14) MM cells. Furthermore, 4C-seq analysis revealed the physical interaction between HJURP-SE and promoter and THZ1 treatment diminished this interaction. Motif search at SE constituents revealed a highly significant enrichment of NSD2 recognition. Significant reduction of NSD2 binding at HJURP-SE region was observed in KMS11 infected with NSD2-specific shRNAs. Interestingly, blocking SE sites by CRISPR/Cas9i or silencing HJURP by shRNA led to decreased HJURP expression and cell apoptosis, whereas overexpression of this gene promoted cell growth. Taken together, our data demonstrated that HJURP is a novel SE-associated oncogene in t(4;14) MM. Conclusions: Our integrative approaches by combing H3K27Ac ChIP-seq, RNA-seq and THZ1-sensitive transcript defined the landscape of SE and identified SE-associated novel oncogenes, as well as lineage-specific TFs in MM. Furthermore, we also revealed subtype-specific SE-driving oncogenic program in MM. Taken together, these results not provide novel insight into the MM pathology, but also offer novel, potential therapeutic targets, such as MAGI2, and HJURP for the treatment of MM patients. Disclosures No relevant conflicts of interest to declare.

A possible alternative mechanism of kinin generation in vivo by cathepsin L

2005 ◽  
Vol 386 (7) ◽  
pp. 699-704 ◽  
Author(s):  
Luciano Puzer ◽  
Juliana Vercesi ◽  
Marcio F.M. Alves ◽  
Nilana M.T. Barros ◽  
Mariana S. Araujo ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Enzyme Inhibitor ◽  
Alternative Pathway ◽  
Cathepsin L ◽  
Specific Inhibitor ◽  
Cysteine Proteases ◽  
Hypotensive Effect ◽  
Alternative Mechanism

Abstract We investigated the ability of cathepsin L to induce a hypotensive effect after intravenous injection in rats and correlated this decrease in blood pressure with kinin generation. Simultaneously with blood pressure decrease, we detected plasma kininogen depletion in the treated rats. The effect observed in vivo was abolished by pre-incubation of cathepsin L with the cysteine peptidase-specific inhibitor E-64 (1 μM) or by previous administration of the bradykinin B2 receptor antagonist JE049 (4 mg/kg). A potentiation of the hypotensive effect caused by cathepsin L was observed by previous administration of the angiotensin I-converting enzyme inhibitor captopril (5 mg/kg). In vitro studies indicated that cathepsin L excised bradykinin from the synthetic fluorogenic peptide Abz-MTSVIRRPPGFSPFRAPRV-NH2, based on the Met375–Val393 sequence of rat kininogen (Abz=o-aminobenzoic acid). In conclusion, our data indicate that in vivo cathepsin L releases a kinin-related peptide, and in vitro experiments suggest that the kinin generated is bradykinin. Although it is well known that cysteine proteases are strongly inhibited by kininogen, cathepsin L could represent an alternative pathway for kinin production in pathological processes.

Inhibiting Alternative Non Homologus Endjoining (NHEJ) Pathways: Therapeutic Targets in Chronic Myeloid Leukemia (CML).

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1088-1088
Author(s):  
Annahita Sallmyr ◽  
Lisa Tobin ◽  
Alan E. Tomkinson ◽  
Feyruz V. Rassool
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Cell Lines ◽  
Small Molecule ◽  
Myeloid Leukemia ◽  
Therapeutic Targets ◽  
Chronic Phase ◽  
Dna Ligase ◽  
Imatinib Treatment ◽  
Dna Ligases ◽  
Dna Deletions

Abstract BCR-ABL fusion tyrosine kinase in chronic myeloid leukemia (CML), induces high levels of ROS that generate DNA double strand breaks (DSBs). We previously showed that CML cells repair DSBs by aberrant non homologous end-joining (NHEJ) that is characterized by large DNA deletions. The generation of DNA deletions represents a mechanism by which genomic alterations may be acquired in the progression of chronic phase CML to blast crisis. Recently, we demonstrated that a “back-up” or alternative NHEJ pathway is involved in aberrant repair of DSBs in CML. Proteins in this pathway include, DNA ligase IIIα, XRCC1 and poly(-ADP) ribose polymerase (PARP). We have identified that NHEJ proteins, DNA ligase IIIα and WRN are overexpressed in CML. This increased expression appears to be dependent on the presence of BCR-ABL. “Knockdown” of these proteins leads to an accumulation of unrepaired DSBs, demonstrating their essential involvement in DSB repair in CML cells. The goal of the current study is to evaluate the effect of inhibiting “back-up” DNA repair proteins in proliferation and apoptosis of BCR-ABL-positive CML compared with standard Imatinib therapy. To evaluate whether “back-up” repair proteins may be therapeutic targets, we used siRNA down-regulation and small molecule inhibition of DNA ligase IIIα and PARP in BCR-ABL positive cell lines. Importantly, we have recently identified small molecule inhibitors of DNA Ligases by computer aided drug design (CADD). Inhibition of DNA ligases and PARP result in a significant increase in apoptosis of CML cells (K562, Kasumi 4, MEG01 and KU812 and P210 MO7e), comparable with the cell death observed with imatinib treatment. Importantly, CML cell lines resistant to imatinib treatment demonstrate similar apoptotic levels in response to “back-up” repair protein inhibition. These inhibitors are in the process of being tested in CML xenografts and mouse models for therapeutic efficacy in vivo. Our data suggest that the survival of CML cells is at least in part maintained by repair of DSBs using “Back-up” NHEJ. The main proteins involved in this pathway, which include DNA ligase IIIα, XRCCI, DNA Ligase I, PARP and WRN have the potential to be novel therapeutic targets in CML patients that have acquired resistance to imatinib.

scholarly journals Synergistic Co-Targeting of BTK and BCL2 in Mantle Cell Lymphoma

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 708-708 ◽  
Author(s):  
Yangguang Li ◽  
Myriam N. Bouchlaka ◽  
Kreg Grindle ◽  
Brad S Kahl ◽  
Shigeki Miyamoto ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Cell Lines ◽  
Therapeutic Strategy ◽  
Cell Lymphoma ◽  
Acquired Resistance ◽  
Specific Inhibitor ◽  
Proteasomal Degradation ◽  
Primary Resistance ◽  
Mantle Cell ◽  
Bcl2 Expression

Abstract Mantle cell lymphoma (MCL), a B-cell non-Hodgkin lymphoma, remains incurable with current treatment modalities. Bruton tyrosine kinase (BTK), a key component of the early BCR signaling pathway, has emerged as a promising therapeutic target. Ibrutinib, a specific inhibitor that binds covalently to the active site of BTK at cysteine 481, has been approved for the treatment of MCL. In a recent Phase II study, treatment for relapsed or refractory MCL with Ibrutinib alone achieved a response rate of 68%. Although this response rate is striking, approximately one third of patients show primary resistance, and acquired resistance with a C481S mutation in BTK can also develop. To overcome primary and acquired resistance to BTK inhibition, a combinatory strategy that targets multiple pathways is needed. Here, we focused on the BCL2 anti-apoptotic pathway. Our previous study established FBXO10 as the E3 ubiquitin ligase that targets BCL2 for proteasomal degradation and revealed reduced levels of FBXO10 expression in MCL cell lines. To examine BCL2 and FBXO10 expression in patient samples, we performed immunohistochemical (IHC) analysis in a tissue microarray (TMA) that contained 62 MCL cases. Our data showed high levels of BCL2 expression but no or low FBXO10 expression in MCL cases. Based on this initial expression analysis, we hypothesized that a defect in FBXO10-mediated proteasomal degradation contributes to high BCL2 expression in MCL. To test this hypothesis, we genetically manipulated FBXO10 expression in MCL cell lines. Flow cytometric analysis revealed that overexpression of FBXO10 resulted in reduced BCL2 expression. Inversely, we silenced endogenous FBXO10 by shRNA. Indeed, after blocking protein synthesis by cycloheximide, the amount of BCL2 protein was sustained in these FBXO10 shRNA-expressing cells. These results indicate that BCL2 is the predominantly expressed anti-apoptotic protein in MCL, due to a specific defect in its proteasomal degradation. Inhibition of BCL2 by the specific inhibitor ABT-199 killed cancer cells in culture and also inhibited xenografted tumor growth. BCL2 is a target gene of the BTK/canonical NF-κB signaling pathway. We next analyzed BTK expression in the above TMA and found that BTK was highly expressed and positively correlated with BCL2 expression in these cases. BTK inhibition reduced BCL2 expression as shown in the BCR-dependent cell lines Jeko and Mino. RNA-seq analysis confirmed that a set of anti-apoptotic genes (e.g. BCL2, BCL-XL and DAD1) was downregulated by BTK shRNA. The downregulated genes also included those that are critical for B cell growth and proliferation, such as BCL6, MYC, PIK3CA and BAFF-R. Elevated BCL2, however, can also result from other mechanisms, such as amplification. Indeed, this genomic alteration is present in some MCL cell lines, including Granta-519 and Z138 used for this study. Since these cell lines are insensitive or less sensitive to Ibrutinib, we hypothesized that BCL2 upregulation is a mechanism underlying primary resistance to Ibrutinib, and thus targeting BCL2 by ABT-199 increases or restores sensitivity of these cells to Ibrutinib. The results supported this hypothesis and demonstrated a synergistic effect of ABT-199 and Ibrutinib on growth inhibition of Granta-519 and Z138 cells both in vitro and in vivo. In summary, this study elucidated mechanisms of BCL2 overexpression and association with the BCR/BTK signaling pathway in MCL. Our data provided a mechanistic rationale for co-targeting of these two oncogenic pathways by ABT-199 and Ibrutinib as a new therapeutic strategy in a pre-clinical setting. Most importantly, the findings indicate that this combination has a synergistic effect on the killing of both BCR-dependent and independent MCL cells. Since these two signaling pathways are deregulated in DLBCL and follicular lymphoma, co-targeting by Ibrutinib and ABT-199 may provide an attractive therapeutic strategy for these additional lymphoma patients as well. Disclosures Kahl: Roche/Genentech: Consultancy; Seattle Genetics: Consultancy; Millennium: Consultancy; Cell Therapeutics: Consultancy; Celgene: Consultancy; Infinity: Consultancy; Pharmacyclics: Consultancy; Juno: Consultancy.

scholarly journals Integrated Analyses of Competing Endogenous RNA Network Reveal Potential Therapeutic Targets in Chronic Lymphocytic Leukemia

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2624-2624
Author(s):  
Xin Zhang ◽  
Ya Zhang ◽  
Yang Han ◽  
Zheng Tian ◽  
Xinting Hu ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Signaling Pathway ◽  
Cell Lines ◽  
Therapeutic Targets ◽  
Enrichment Analysis ◽  
Lymphocytic Leukemia ◽  
Functional Enrichment ◽  
Differentially Expressed ◽  
Cerna Network ◽  
And Control

Abstract Introduction Chronic lymphocytic leukemia (CLL) is a highly heterogeneous disease characterized by malignant clonal expansion of mature B lymphocytes. Competitive endogenous RNAs(ceRNAs) such as long noncoding RNAs (lncRNAs) and circular RNAs (circ RNAs) have miRNA response elements (MREs) and can bind to miRNAs to influence mRNA expression. An increasing number of studies have shown that the ceRNA network played an important role in the initiation and progression of tumors. However, the roles and functions of the ceRNA network in chronic lymphocytic leukemia (CLL) are still unclear. This study aims to explore the molecular mechanism of CLL and provide potential prognostic markers and therapeutic targets through the integrated analysis of the ceRNA network in CLL. Methods The expression profile of RNAs of CLL patients, CLL cell lines (MEC1 and EHEB) and healthy group were obtained by the illumina sequencing. R software was used for functional enrichment analysis. The data in the genome microarray map GSE22762 was used for survival analysis. The circRNA-miRNA-mRNA ceRNA networks were visualized by Cytoscape 3.7.2. The expression of the circRNA hsa_circ_0007675/hsa-miR-185-3p/TCF7L1 axis were verified by Quantitative real-time PCR and the correlation between hsa_circ_0007675 and TCF7L1 was analyzed. Results In total, we identified 57 differentially expressed mRNAs (DEmRNAs), 1391 DElncRNAs, 335 DEmiRNAs and 2413 DEcircRNAs by comparing CLL patients with healthy donors. Meanwhile, 482 mRNAs, 6085 lncRNAs, 302 miRNAs and 1847 circRNAs were explored differently expressed between CLL cell lines and healthy donors. GO analysis results showed that the functions of differentially expressed genes (DEGs) between CLL patients and control are mainly enriched in sequence−specific DNA binding, chromatin and gene expression (Figure 1A) while between CLL cell lines and control they were mainly enriched in oxidoreductase activity, ribosomal subunit and lipid metabolism (Figure 1C). KEGG pathway analysis revealed that the DEGs between CLL patients and control were mainly enriched in Notch signaling pathway, JAK-STAT signaling pathway and cGMP-PKG signaling pathway (Figure 1B). Meanwhile between CLL cell lines and control, DEGs were mainly enriched in mTOR signaling pathway, cell cycle and p53 signaling pathway (Figure 1D). The survival analyses showed that 15 DEGs (INIP, IL3RA, CHD1, NLRP12, IL20RB, HNRNPC, B3GALT4, SIT1, ACOT8, PCLAF, C19orf18, SELENOS, OR7A17, PCDH7, PHGDH) were significantly differentially expressed in the survival analyses. The overall survival of the high expression group of INIP, IL3RA, CHD1, NLRP12, IL20RB and HNRNPC were higher than that of the low expression group (Figure 2A-F) while the overall survival of the low expression group of B3GALT4, SIT1, ACOT8, PCLAF, C19orf18, SELENOS, OR7A17, PCDH7 and PHGDH were higher than that of the high expression group (Figure 2G-O). The ceRNA network were built by Cytoscape3.7.2. In total, 11 mRNA nodes, 19 miRNA nodes, 251 circRNA nodes were identified as differentially expressed profiles between CLL patients and control (Figure 3A). We verified the circRNA hsa_circ_0007675/hsa-miR-185-3p/TCF7L1 axis. Compared with normal people, the expression of TCF7L1 and hsa_circ_0007675 in patient specimens were significantly increased (p<0.05; Figure 3B, D) whereas the expression of hsa-miR-185-3p was downregulated (p<0.05; Figure 3C). TCF7L1 and hsa_circ_0007675 were positively correlated (p＜0.001, R=0.7834; Figure 3E). The correlation analysis of TCF7L1 and other genes were shown in Figure 3F. The interaction mechanism between them is that hsa_circ_0007675 can sponge hsa-miR-185-3p, thereby inhibiting the inhibitory effect of hsa-miR-185-3p on TCF7L1 and finally upregulate the expression of TCF7L1(Figure 3G). Conclusions In this study, we identified the expression profile of RNAs in CLL patients and CLL cell lines. Functional enrichment analysis and survival analysis revealed the potential functions of DEGs. The ceRNA network we established can help to further understand the pathogenesis of CLL and provide potential prognostic biomarkers and novel therapeutic targets. Keywords: Chronic lymphocytic leukemia; Competing endogenous RNA; Non-coding RNAs; Prognostic biomarkers; Therapeutic targets Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

MAPK: A Key Player in the Development and Progression of Stroke

2020 ◽  
Vol 19 (4) ◽  
pp. 248-256
Author(s):  
Yangmin Zheng ◽  
Ziping Han ◽  
Haiping Zhao ◽  
Yumin Luo
Keyword(s):  
Ischemic Stroke ◽  
Signaling Pathway ◽  
Complex Disease ◽  
Therapeutic Targets ◽  
Cell Types ◽  
Mapk Signaling ◽  
Mapk Signaling Pathway ◽  
Effective Prevention ◽  
Prevention And Treatment ◽  
Different Cell Types

Conclusion: Stroke is a complex disease caused by genetic and environmental factors, and its etiological mechanism has not been fully clarified yet, which brings great challenges to its effective prevention and treatment. MAPK signaling pathway regulates gene expression of eukaryotic cells and basic cellular processes such as cell proliferation, differentiation, migration, metabolism and apoptosis, which are considered as therapeutic targets for many diseases. Up to now, mounting evidence has shown that MAPK signaling pathway is involved in the pathogenesis and development of ischemic stroke. However, the upstream kinase and downstream kinase of MAPK signaling pathway are complex and the influencing factors are numerous, the exact role of MAPK signaling pathway in the pathogenesis of ischemic stroke has not been fully elucidated. MAPK signaling molecules in different cell types in the brain respond variously after stroke injury, therefore, the present review article is committed to summarizing the pathological process of different cell types participating in stroke, discussed the mechanism of MAPK participating in stroke. We further elucidated that MAPK signaling pathway molecules can be used as therapeutic targets for stroke, thus promoting the prevention and treatment of stroke.

scholarly journals Hsa_circ_0005273 facilitates breast cancer tumorigenesis by regulating YAP1-hippo signaling pathway

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Xuehui Wang ◽  
Changle Ji ◽  
Jiashu Hu ◽  
Xiaochong Deng ◽  
Wenfang Zheng ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Signaling Pathway ◽  
Cell Lines ◽  
Luciferase Reporter ◽  
Circular Rnas ◽  
Hippo Signaling ◽  
Hippo Signaling Pathway ◽  
Potential Biomarker

Abstract Background Circular RNAs (circRNAs), a novel class of endogenous RNAs, have shown to participate in the development of breast cancer (BC). Hsa_circ_0005273 is a circRNA generated from several exons of PTK2. However, the potential functional role of hsa_circ_0005273 in BC remains largely unknown. Here we aim to evaluate the role of hsa_circ_0005273 in BC. Methods The expression level of hsa_circ_0005273 and miR-200a-3p were examined by RT-qPCR in BC tissues and cell lines. The effect of knocking down hsa_circ_0005273 in BC cell lines were evaluated by examinations of cell proliferation, migration and cell cycle. In addition, xenografts experiment in nude mice were performed to evaluate the effect of hsa_circ_0005273 in BC. RNA immunoprecipitation assay, RNA probe pull-down assay, luciferase reporter assay and fluorescence in situ hybridization were conducted to confirm the relationship between hsa_circ_0005273, miR-200a-3p and YAP1. Results Hsa_circ_0005273 is over-expressed in BC tissues and cell lines, whereas miR-200a-3p expression is repressed. Depletion of hsa_circ_0005273 inhibited the progression of BC cells in vitro and in vivo, while overexpression of hsa_circ_0005273 exhibited the opposite effect. Importantly, hsa_circ_0005273 upregulated YAP1 expression and inactivated Hippo pathway via sponging miR-200a-3p to promote BC progression. Conclusions Hsa_circ_0005273 regulates the miR-200a-3p/YAP1 axis and inactivates Hippo signaling pathway to promote BC progression, which may become a potential biomarker and therapeutic target.

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