scholarly journals ALKBH5 Functions As an Oncogene in Multiple Myeloma

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3326-3326
Author(s):  
Jianwei Qu ◽  
Yifan Hou ◽  
Qingxiao Chen ◽  
Jing Chen ◽  
YI LI ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Signaling Pathways ◽  
Gene Set Enrichment Analysis ◽  
Luciferase Reporter ◽  
Dependent Manner ◽  
Immunoprecipitation Assay ◽  
Enzymatic Function ◽  
Demethylation Activity

Abstract Background: RNA N 6-methyladenosine (m 6A) plays a critical role in regulating gene expression and determining cell fate. The dysregulation of m 6A modulators, including α-ketoglutarate-dependent dioxygenase AlkB homolog 5 (ALKBH5), has been reported to promote tumor development through their enzymatic function. However, the functions of mRNA m 6A and its modulators in multiple myeloma (MM) are largely unknown. Methods: We queried publicly available MM datasets to study the expression profile of m 6A modulators (METTL3, METTL14, WTAP, FTO, and ALKBH5) in MM and their relationships with clinical outcomes in patients with MM. Both gain- and loss-of-function studies were performed to investigate the role of ALKBH5 in MM. The cell proliferation assay, colony formation assay, Annexin V apoptosis analysis, and 5-ethynyl-2′-deoxyuridine (EdU) assay were performed to evaluate the functions of ALKBH5 in MM in vitro. Human MM cell line xenograft models were constructed to examine the effects of ALKBH5 knockdown or overexpression on MM growth in vivo. The rescue assay using catalytically inactive mutant ALKBH5-H204A was conducted to determine whether demethylation activity was required for the function of ALKBH5 in MM. Then, we performed RNA sequencing and m 6A sequencing to explore the key targets that mediated ALKBH5 function in MM. We investigated the gene regulatory mechanism of ALKBH5 in MM by m 6A immunoprecipitation assay, RNA immunoprecipitation assay, RNA decay assay, dual-luciferase reporter assay, and so forth. Gene set enrichment analysis and Western blotting were employed to determine the downstream signaling pathways regulated by ALKBH5 and the recognized target. Results: ALKBH5 was overexpressed in MM and associated with a poor prognosis in patients with MM. The increased ALKBH5 expression was required for the survival and growth of MM cells in vitro and in vivo. Mechanistically, m 6A demethylation activity was required for ALKBH5 to exert tumorigenic effects in MM. Tumor necrosis factor (TNF) receptor-associated factor 1 (TRAF1) was identified as a functionally important target of ALKBH5. ALKBH5 regulated TRAF1 expression via affecting mRNA stability of TRAF1 in an m 6A- and YTHDF2-dependent manner. ALKBH5 promoted MM cell growth and survival partly through TRAF1-mediated activation of NF-κB and MAPK signaling pathways. Conclusion: Our findings showed that ALKBH5 played an oncogenic role in MM and highlighted that ALKBH5 could potentially be a novel therapeutic target in MM. Disclosures No relevant conflicts of interest to declare.

scholarly journals RNA demethylase ALKBH5 promotes tumorigenesis in multiple myeloma via TRAF1-mediated activation of NF-κB and MAPK signaling pathways

Oncogene ◽  
2021 ◽  
Author(s):  
Jianwei Qu ◽  
Yifan Hou ◽  
Qingxiao Chen ◽  
Jing Chen ◽  
Yi Li ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Signaling Pathways ◽  
Critical Role ◽  
Enrichment Analysis ◽  
Mapk Signaling ◽  
Gene Set Enrichment Analysis ◽  
Dependent Manner ◽  
Growth And Survival ◽  
Mapk Signaling Pathways

AbstractN6-methyladenosine (m6A), an internal modification in mRNA, plays a critical role in regulating gene expression. Dysregulation of m6A modifiers promotes oncogenesis through enzymatic functions that disrupt the balance between the deposition and removal of m6A modification on critical transcripts. However, the roles of mRNA m6A in multiple myeloma (MM) are poorly understood. The present study showed that RNA demethylase ALKBH5 was overexpressed in MM and associated with a poor prognosis in MM patients. Knocking down ALKBH5 induced apoptosis and inhibited the growth of MM cells in vitro. Xenograft models and gene set enrichment analysis with patient transcriptome datasets also supported the oncogenic role of ALKBH5 in MM. Mechanistic studies showed that ALKBH5 exerted tumorigenic effects in myeloma in an m6A-dependent manner, and TNF receptor-associated factor 1 (TRAF1) was a critical target of ALKBH5. Specifically, ALKBH5 regulated TRAF1 expression via decreasing m6A abundance in the 3'-untranslated region (3'-UTR) of TRAF1 transcripts and enhancing TRAF1 mRNA stability. As a result, ALKBH5 promoted MM cell growth and survival through TRAF1-mediated activation of NF-κB and MAPK signaling pathways. Collectively, our data demonstrated that ALKBH5 played a critical role in MM tumorigenesis and suggested that ALKBH5 could be a novel therapeutic target in MM.

scholarly journals Anti-tumor activity of a novel proteasome inhibitor D395 against multiple myeloma and its lower cardiotoxicity compared with carfilzomib

2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Xuxing Shen ◽  
Chao Wu ◽  
Meng Lei ◽  
Qing Yan ◽  
Haoyang Zhang ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Proteasome Inhibitor ◽  
Osteoclast Differentiation ◽  
Dependent Manner ◽  
Serum Enzyme ◽  
Herg Channels ◽  
Anti Tumor Activity ◽  
Dose Dependent

AbstractCarfilzomib, a second-generation proteasome inhibitor, has significantly improved the survival rate of multiple myeloma (MM) patients, but its clinical application is still restricted by drug resistance and cardiotoxicity. Here, we identified a novel proteasome inhibitor, D395, and assessed its efficacy in treating MM as well as its cardiotoxicity at the preclinical level. The activities of purified and intracellular proteasomes were measured to determine the effect of D395 on the proteasome. CCK-8 and flow cytometry experiments were designed to evaluate the effects of D395 on cell growth and apoptosis. The effects of D395 and carfilzomib on serum enzyme activity, echocardiography features, cardiomyocyte morphology, and hERG channels were also compared. In our study, D395 was highly cytotoxic to MM cell lines and primary MM cells but not normal cells, and it was well tolerated in vivo. Similar to carfilzomib, D395 inhibited osteoclast differentiation in a dose-dependent manner. In particular, D395 exhibited lower cardiotoxicity than carfilzomib in all experiments. In conclusion, D395 is a novel irreversible proteasome inhibitor that has remarkable anti-MM activity and mild cardiotoxicity in vitro and in vivo.

Homeobox-A13 acts as a functional prognostic and diagnostic biomarker via regulating P53 and Wnt signaling pathways in lung cancer

2021 ◽  
pp. 1-16
Author(s):  
Yang Wang ◽  
Bo He ◽  
Yan Dong ◽  
Gong-Jin He ◽  
Xiao-Wei Qi ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Signaling Pathways ◽  
Cox Regression ◽  
Prognostic Significance ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Clinical Feature ◽  
Diagnostic Biomarker

BACKGROUND: The prognosis of lung cancer patients is poor without useful prognostic and diagnostic biomarker. To search for novel prognostic and diagnostic markers, we previously found homeobox-A13 (HOXA13) as a promising candidate in lung cancer. OBJECTIVE: To determine the precisely clinical feature, prognostic and diagnostic value, possible role and mechanism of HOXA13. METHODS: Gene-expression was explored by real-time quantitative-PCR, western-blot and tissue-microarray. The associations were analyzed by Chi-square test, Kaplan-Meier and Cox-regression. The roles and mechanisms were evaluated by MTS, EdU, transwell, xenograft tumor and luciferase-reporter assays. RESULTS: HOXA13 expression is increased in tumors, and correlated with age of patients. HOXA13 expression is associated with unfavorable overall survival and relapse-free survival of patients in four cohorts. Interestingly, HOXA13 has different prognostic significance in adenocarcinoma (ADC) and squamous-cell carcinoma (SCC), and is a sex- and smoke-related prognostic factor only in ADC. Importantly, HOXA13 can serve as a diagnostic biomarker for lung cancer, especially for SCC. HOXA13 can promote cancer-cell proliferation, migration and invasion in vitro, and facilitate tumorigenicity and tumor metastasis in vivo. HOXA13 acts the oncogenic roles on tumor growth and metastasis by regulating P53 and Wnt/β-catenin signaling activities in lung cancer. CONCLUSIONS: HOXA13 is a new prognostic and diagnostic biomarker associated with P53 and Wnt/β-catenin signaling pathways.

scholarly journals Positive Crosstalk Between Hedgehog and NF-κB Pathways Is Dependent on KRAS Mutation in Pancreatic Ductal Adenocarcinoma

2021 ◽  
Vol 11 ◽  
Author(s):  
Yuqiong Wang ◽  
Dan Wang ◽  
Yanmiao Dai ◽  
Xiangyu Kong ◽  
Xian Zhu ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Pancreatic Ductal Adenocarcinoma ◽  
Signaling Pathways ◽  
Kras Mutation ◽  
Biological Effects ◽  
Ductal Adenocarcinoma ◽  
Luciferase Reporter ◽  
Hh Signaling

It has been shown that aberrant activation of the Hedgehog (Hh) and nuclear factor-kappa B (NF-κB) signaling pathways plays an important role in the pancreatic carcinogenesis, and KRAS mutation is a hallmark of pancreatic ductal adenocarcinoma (PDAC). Until now, the role of KRAS mutation in the context of crosstalk between Hh and NF-κB signaling pathways in PDAC has not been investigated. This study was to determine whether the crosstalk between the Hh and NF-κB pathways is dependent on KRAS mutation in PDAC. The correlation between Gli1, Shh, NF-κB p65 expression and KRAS mutation in PDAC tissues was firstly examined by immunohistochemistry. Next, Western blotting, qPCR, and immunofluorescence were conducted to examine the biological effects of interleukin-1β (IL-1β) and tumor necrosis factor-alpha (TNF-α) as NF-κB signaling agonists, Shh as an Hh ligand alone or in combination with KRAS small interfering RNA (si-KRAS) in KRAS-mutant PDAC cells (MT-KRAS; SW1990 and Panc-1), wild-type KRAS PDAC cells (WT-KRAS; BxPC-3) and mutant KRAS knock-in BxPC-3 cells in vitro as well as tumor growth in vivo. KRAS mutation-dependent crosstalk between Hh and NF-κB in PDAC cells was further assessed by Ras activity and luciferase reporter assays. The aberrant Hh and NF-κB pathway activation was found in PDAC tissues with KRAS mutation. The same findings were confirmed in MT-KRAS PDAC cells and MT-KRAS knock-in BxPC-3 cells, whereas this activation was not observed in WT-KRAS PDAC cells. However, the activation was significantly down-regulated by KRAS silencing in MT-KRAS PDAC cells. Furthermore, MT-KRAS cancer cell proliferation and survival in vitro and tumor growth after inoculation with MT-KRAS cells in vivo were promoted by NF-κB and Hh signaling activation. The pivotal factor for co-activation of NF-κB and Hh signaling is MT-KRAS protein upregulation, showing that positive crosstalk between Hh and NF-κB pathways is dependent upon KRAS mutation in PDAC.

scholarly journals Network Pharmacology Analysis and Experiments Validation of the Inhibitory Effect of JianPi Fu Recipe on Colorectal Cancer LoVo Cells Metastasis and Growth

2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Xinyi Lu ◽  
Xingli Wu ◽  
Lin Jing ◽  
Lingjia Tao ◽  
Yingxuan Zhang ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Drug Targets ◽  
Biological Function ◽  
Network Pharmacology ◽  
Dependent Manner ◽  
Active Compounds ◽  
Dose Dependent ◽  
Potential Drug Targets

Objective. To analyze the active compounds, potential targets, and diseases of JianPi Fu Recipe (JPFR) based on network pharmacology and bioinformatics and verify the potential biological function and mechanism of JPFR in vitro and in vivo. Methods. Network pharmacology databases including TCMSP, TCM-PTD, TCMID, and DrugBank were used to screen the active compounds and potential drug targets of JPFR. Cytoscape 3.7 software was applied to construct the interaction network between active compounds and potential targets. The DAVID online database analysis was performed to investigate the potential effective diseases and involved signaling pathways according to the results of the GO function and KEGG pathways enrichment analysis. To ensure standardization and maintain interbatch reliability of JPFR, High Performance Liquid Chromatography (HPLC) was used to establish a “chemical fingerprint.” For biological function validation, the effect of JPFR on the proliferation and migration of CRC cells in vitro was investigated by CCK-8 and transwell and wound healing assay, and the effect of JPFR on the growth and metastasis of CRC cells in vivo was detected by building a lung metastasis model in nude mice and in vivo imaging. For the potential mechanism validation, the expressions of MALAT1, PTBP-2, and β-catenin in CRC cells and transplanted CRC tumors were detected by real-time PCR, western blot, and immunohistochemical staining analysis. Results. According to the rules of oral bioavailability (OB) > 30% and drug-likeness (DL) > 0.18, 244 effective compounds in JPFR were screened out, as well as the corresponding 132 potential drug targets. By the analysis of DAVID database, all these key targets were associated closely with the cancer diseases such as prostate cancer, colorectal cancer, bladder cancer, small cell lung cancer, pancreatic cancer, and hepatocellular carcinoma. In addition, multiple signaling pathways were closely related to JPFR, including p53, Wnt, PI3K-Akt, IL-17, HIF-1, p38-MAPK, NF-κB, PD-L1 expression and PD-1 checkpoint pathway, VEGF, JAK-STAT, and Hippo. The systematical analysis showed that various active compounds of JPFR were closely connected with Wnt/β-catenin, EGFR, HIF-1, TGFβ/Smads, and IL6-STAT3 signaling pathway, including kaempferol, isorhamnetin, calycosin, quercetin, medicarpin, phaseol, spinasterol, hederagenin, beta-sitosterol, wighteone, luteolin, and isotrifoliol. For in vitro experiments, the migration and growth of human CRC cells were inhibited by the JPFR extract in a dose-dependent way, and the expression of MALAT1, PTBP-2, β-catenin, MMP7, c-Myc, and Cyclin D1 in CRC cells were downregulated by the JPFR extract in a dose-dependent way. For in vivo metastasis experiments, the numbers of lung metastasis were found to be decreased by the JPFR extract in a dose-dependent manner, and the expressions of metastasis-associated genes including MALAT1, PTBP-2, β-catenin, and MMP7 in the lung metastases were downregulated dose dependently by the JPFR extract. For the orthotopic transplanted tumor experiments, the JPFR extract could inhibit the growth of orthotopic transplanted tumors and downregulate the expression of c-Myc and Cyclin D1 in a dose-dependent manner. Moreover, the JPFR extract could prolong the survival time of tumor-bearing mice in a dose-dependent manner. Conclusions. Through effective network pharmacology analysis, we found that JPFR contains many effective compounds which may directly target cancer-associated signaling pathways. The in vitro and in vivo experiments further confirmed that JPFR could inhibit the growth and metastasis of CRC cells by regulating β-catenin signaling-associated genes or proteins.

NVP-LAQ824 is a potent novel histone deacetylase inhibitor with significant activity against multiple myeloma

Blood ◽  
2003 ◽  
Vol 102 (7) ◽  
pp. 2615-2622 ◽  
Author(s):  
Laurence Catley ◽  
Ellen Weisberg ◽  
Yu-Tzu Tai ◽  
Peter Atadja ◽  
Stacy Remiszewski ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Histone Deacetylase ◽  
Hdac Inhibitors ◽  
Myeloma Cell ◽  
Parp Cleavage ◽  
Significant Activity ◽  
Dependent Manner

Abstract Histone deacetylase (HDAC) inhibitors are emerging as a promising new treatment strategy in hematologic malignancies. Here we show that NVP-LAQ824, a novel hydroxamic acid derivative, induces apoptosis at physiologically achievable concentrations (median inhibitory concentration [IC50] of 100 nM at 24 hours) in multiple myeloma (MM) cell lines resistant to conventional therapies. MM.1S myeloma cell proliferation was also inhibited when cocultured with bone marrow stromal cells, demonstrating ability to overcome the stimulatory effects of the bone marrow microenvironment. Importantly, NVP-LAQ824 also inhibited patient MM cell growth in a dose- and time-dependent manner. NVP-LAQ824-induced apoptotic signaling includes up-regulation of p21, caspase cascade activation, and poly (adenosine diphosphate [ADP]) ribose (PARP) cleavage. Apoptosis was confirmed with cell cycle analysis and annexin-propidium iodide staining. Interestingly, treatment of MM cells with NVPLAQ824 also led to proteasome inhibition, as determined by reduced proteasome chymotrypsin-like activity and increased levels of cellular polyubiquitin conjugates. Finally, a study using NVP-LAQ824 in a preclinical murine myeloma model provides in vivo relevance to our in vitro studies. Taken together, these findings provide the framework for NVP-LAQ824 as a novel therapeutic in MM. (Blood. 2003;102:2615-2622)

scholarly journals Enhanced Expression of miR-34a Enhances Escherichia coli Lipopolysaccharide-Mediated Endometritis by Targeting LGR4 to Activate the NF-κB Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Xiaofei Ma ◽  
Baoyi Yin ◽  
Shuai Guo ◽  
Talha Umar ◽  
Junfeng Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacterial Infections ◽  
Luciferase Reporter ◽  
Blue Staining ◽  
Histopathological Analysis ◽  
Dependent Manner ◽  
Luciferase Reporter Gene ◽  
Gram Staining

Background. Persistent endometritis caused by bacterial infections has lethal effects on the reproductive performance of dairy cattle, which compromises animal welfare and delays or prevents pregnancy. The microRNA (miRNA) miR-34 family plays a pivotal role in the inflammatory process; however, the precise mechanism of miR-34a in endometritis has not been thoroughly elucidated to date. Methods. In this study, the endometrium of cows diagnosed with endometritis was harvested for bacterial culture and Gram staining to evaluate bacterial contamination of the uterus. Based on this, a bovine endometrial epithelial cell (BEND) inflammation model and a mouse model stimulated with lipopolysaccharide (LPS) in vitro and in vivo were constructed. Cell viability was assessed by CCK-8, trypan blue staining, and flow cytometry. H&E was applied to histopathological analysis. Immunohistochemical, immunofluorescence, qRT-PCR, and western blot assays were performed to measure the mRNA and protein expression of relevant genes. Online databases, plasmid construction, and dual-luciferase reporter gene assays were used to predict and validate the interaction between miR-34a and its target gene LGR4. Finally, mice were injected vaginally with a local antagomir to validate the role of miR-34a in murine uterine inflammation. Results. In this study, we observed that Gram-negative bacteria, represented by Escherichia coli, are the predominant pathogenic agents responsible for the recurrent occurrence of endometritis in dairy cows. Further, miR-34a was found to repress the expression of LGR4 by targeting the 3 ′ untranslated region (3 ′ UTR) of LGR4. miR-34a was upregulated in bovine uterine tissues and bovine endometrial epithelial cells stimulated with LPS. miR-34a induced the release of the proinflammatory cytokines IL-1β, IL-6, and TNF-α by activating the phosphorylation of NF-κB p65. Furthermore, IL-1β upregulated miR-34a transcription and downregulated LGR4 expression in an IL-1β-dependent manner. Conclusions. Taken together, our study confirmed that miR-34a is regulated by IL-1β and suppresses the level of the LGR4 3 ′ UTR, which in turn exacerbates the inflammatory response. Thus, the knockdown of miR-34a might be a new direction for the treatment of endometritis.

scholarly journals Epigenetic regulation of ferroptosis via ETS1/miR-23a-3p/ACSL4 axis mediates sorafenib resistance in human hepatocellular carcinoma

2022 ◽  
Vol 41 (1) ◽  
Author(s):  
Yuanjun Lu ◽  
Yau-Tuen Chan ◽  
Hor-Yue Tan ◽  
Cheng Zhang ◽  
Wei Guo ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Drug Resistance ◽  
Molecular Mechanisms ◽  
Luciferase Reporter ◽  
Dependent Manner ◽  
Bioinformatics Analyses ◽  
Sorafenib Treatment ◽  
Hcc Cells

Abstract Background Drug resistance to sorafenib greatly limited the benefits of treatment in patients with hepatocellular carcinoma (HCC). MicroRNAs (miRNAs) participate in the development of drug resistance. The key miRNA regulators related to the clinical outcome of sorafenib treatment and their molecular mechanisms remain to be identified. Methods The clinical significance of miRNA-related epigenetic changes in sorafenib-resistant HCC was evaluated by analyzing publicly available databases and in-house human HCC tissues. The biological functions of miR-23a-3p were investigated both in vitro and in vivo. Proteomics and bioinformatics analyses were conducted to identify the mechanisms that regulating miR-23a-3p. Luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay were used to validate the binding relationship of miR-23a-3p and its targets. Results We found that miR-23a-3p was the most prominent miRNA in HCC, which was overexpressed in sorafenib non-responders and indicated poor survival and HCC relapse. Sorafenib-resistant cells exhibited increased miR-23a-3p transcription in an ETS Proto-Oncogene 1 (ETS1)-dependent manner. CRISPR-Cas9 knockout of miR-23a-3p improved sorafenib response in HCC cells as well as orthotopic HCC tumours. Proteomics analysis suggested that sorafenib-induced ferroptosis was the key pathway suppressed by miR-23a-3p with reduced cellular iron accumulation and lipid peroxidation. MiR-23a-3p directly targeted the 3′-untranslated regions (UTR) of ACSL4, the key positive regulator of ferroptosis. The miR-23a-3p inhibitor rescued ACSL4 expression and induced ferrotoptic cell death in sorafenib-treated HCC cells. The co-delivery of ACSL4 siRNA and miR-23a-3p inhibitor abolished sorafenib response. Conclusion Our study demonstrates that ETS1/miR-23a-3p/ACSL4 axis contributes to sorafenib resistance in HCC through regulating ferroptosis. Our findings suggest that miR-23a-3p could be a potential target to improve sorafenib responsiveness in HCC patients.

scholarly journals The Long Non-coding RNA TMPO-AS1  Promotes Bladder Cancer Growth and Progression via OTUB1-induced E2F1 Deubiquitination

2020 ◽  
Author(s):  
Yeyu Zhang ◽  
Yuxing Zhu ◽  
Mengqing Xiao ◽  
Yaxin Cheng ◽  
Dong He ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Molecular Mechanisms ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Dependent Manner ◽  
E2f Transcription Factor ◽  
Rna Immunoprecipitation ◽  
Regulatory Loop

Abstract BackgroundBladder cancer (BC) is the most common malignant tumor of the urinary system. Increasing evidence indicates long non-coding RNAs (lncRNAs) play crucial roles in cancer tumorigenesis, development, and progression. However, the role of TMPO antisense RNA 1 (TMPO-AS1) is still need to be explored in BC.MethodsThe lncRNA TMPO-AS1 expression was evaluated by bioinformatics analysis and further validated by qRT-PCR. Loss- and gain-of- function assays were performed to determine the biological functions of TMPO-AS1 in BC proliferation, migration, and invasion. Chromatin immunoprecipitation, luciferase reporter assays, western blotting, RNA pull-down, RNA immunoprecipitation assays, and fluorescence in situ hybridization were conducted to explore the molecular mechanisms of TMPO-AS1/E2F transcription factor 1 (E2F1) loop. ResultsTMPO-AS1 is upregulated in bladder cancer and is associated with BC patients’ poor prognoses. Functional experiments demonstrated that TMPO-AS1 promotes bladder cancer cell proliferation, migration, invasion, and inhibits cell apoptosis in vivo and in vitro. Mechanically, E2F1 is responsible for the TMPO-AS1 upregulation. Additionally, TMPO-AS1 facilitates the interaction of E2F1 with OTU domain-containing ubiquitin aldehyde binding 1 (OTUB1), leading to E2F1 deubiquitination and stabilization, thereby promotes BC malignant phenotypes. Furthermore, rescue experiments showed that TMPO-AS1 promotes BC growth in an E2F1-dependent manner.ConclusionsOur study is the first to uncover a novel positive regulatory loop of TMPO-AS1/E2F1 important for the promotion of BC malignant behaviors. The TMPO-AS1/E2F1 loop should be considered in the quest for new BC therapeutic options.

scholarly journals Cross-talk between SIM2s and NFκB regulates cyclooxygenase 2 expression in breast cancer

2019 ◽  
Vol 21 (1) ◽  
Author(s):  
Garhett L. Wyatt ◽  
Lyndsey S. Crump ◽  
Chloe M. Young ◽  
Veronica M. Wessells ◽  
Cole M. McQueen ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cyclooxygenase 2 ◽  
Luciferase Reporter ◽  
Signaling Proteins ◽  
Dependent Manner ◽  
Mcf7 Cells ◽  
Human Breast Carcinomas ◽  
Cox 2

Abstract Background Breast cancer is a leading cause of cancer-related death for women in the USA. Thus, there is an increasing need to investigate novel prognostic markers and therapeutic methods. Inflammation raises challenges in treating and preventing the spread of breast cancer. Specifically, the nuclear factor kappa b (NFκB) pathway contributes to cancer progression by stimulating proliferation and preventing apoptosis. One target gene of this pathway is PTGS2, which encodes for cyclooxygenase 2 (COX-2) and is upregulated in 40% of human breast carcinomas. COX-2 is an enzyme involved in the production of prostaglandins, which mediate inflammation. Here, we investigate the effect of Singleminded-2s (SIM2s), a transcriptional tumor suppressor that is implicated in inhibition of tumor growth and metastasis, in regulating NFκB signaling and COX-2. Methods For in vitro experiments, reporter luciferase assays were utilized in MCF7 cells to investigate promoter activity of NFκB and SIM2. Real-time PCR, immunoblotting, immunohistochemistry, and chromatin immunoprecipitation assays were performed in SUM159 and MCF7 cells. For in vivo experiments, MCF10DCIS.COM cells stably expressing SIM2s-FLAG or shPTGS2 were injected into SCID mice and subsequent tumors harvested for immunostaining and analysis. Results Our results reveal that SIM2 attenuates the activation of NFκB as measured using NFκB-luciferase reporter assay. Furthermore, immunostaining of lysates from breast cancer cells overexpressing SIM2s showed reduction in various NFκB signaling proteins, as well as pAkt, whereas knockdown of SIM2 revealed increases in NFκB signaling proteins and pAkt. Additionally, we show that NFκB signaling can act in a reciprocal manner to decrease expression of SIM2s. Likewise, suppressing NFκB translocation in DCIS.COM cells increased SIM2s expression. We also found that NFκB/p65 represses SIM2 in a dose-dependent manner, and when NFκB is suppressed, the effect on the SIM2 is negated. Additionally, our ChIP analysis confirms that NFκB/p65 binds directly to SIM2 promoter site and that the NFκB sites in the SIM2 promoter are required for NFκB-mediated suppression of SIM2s. Finally, overexpression of SIM2s decreases PTGS2 in vitro, and COX-2 staining in vivo while decreasing PTGS2 and/or COX-2 activity results in re-expression of SIM2. Conclusion Our findings identify a novel role for SIM2s in NFκB signaling and COX-2 expression.

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