scholarly journals Arginine Methyltransferase PRMT5 Methylates and Destabilizes Mxi1 to Confer Radioresistance in Lung Cancer

Author(s):  
Xijie Yang ◽  
Zhen Zeng ◽  
Xiaohua Jie ◽  
Ye Wang ◽  
Jun Han ◽  
...  

Abstract BackgroundRadioresistance is regarded as the main cause of local recurrence and distant metastasis in lung cancer. However, the underlying mechanisms of radioresistance remain incompletely understood. This study investigates the roles and regulatory mechanisms of arginine methyltransferase PRMT5 in lung cancer radioresistance.MethodsImmunoprecipitation assay and GST pulldown were used to detect the protein-protein interaction. The methylation of Mxi1 was determined by in vivo and in vitro arginine methylation assays. In vivo ubiquitination and CHX chase assays were performed to examine the stability of Mxi1. The biological effects of PRMT5 and its specific inhibitor EPZ015666 in lung cancer were evaluated both in vitro and in vivo.ResultsWe show that the arginine methyltransferase PRMT5 interacts with and methylates Mxi1, which promotes the binding of the β-Trcp ligase to Mxi1, facilitating the ubiquitination and degradation of Mxi1 in lung cancer. Furthermore, genetic blockade of PRMT5 impairs DNA damage repair and enhances lung cancer radiosensitivity in vitro and in vivo, and these phenotypes are partially reversed by Mxi1 silencing. More importantly, pharmacological inhibition of PRMT5 with the specific inhibitor EPZ015666 leads to extraordinary radiosensitization in vitro and in vivo in lung cancer.ConclusionsOur data indicate that PRMT5 methylates and destabilizes Mxi1 to confer radioresistance, suggesting that PRMT5 may be a promising radiosensitization target in lung cancer.

Author(s):  
Xiaohua Jie ◽  
William Pat Fong ◽  
Rui Zhou ◽  
Ye Zhao ◽  
Yingchao Zhao ◽  
...  

AbstractRadioresistance is regarded as the main barrier to effective radiotherapy in lung cancer. However, the underlying mechanisms of radioresistance remain elusive. Here, we show that lysine-specific demethylase 4C (KDM4C) is overexpressed and correlated with poor prognosis in lung cancer patients. We provide evidence that genetical or pharmacological inhibition of KDM4C impairs tumorigenesis and radioresistance in lung cancer in vitro and in vivo. Moreover, we uncover that KDM4C upregulates TGF-β2 expression by directly reducing H3K9me3 level at the TGF-β2 promoter and then activates Smad/ATM/Chk2 signaling to confer radioresistance in lung cancer. Using tandem affinity purification technology, we further identify deubiquitinase USP9X as a critical binding partner that deubiquitinates and stabilizes KDM4C. More importantly, depletion of USP9X impairs TGF-β2/Smad signaling and radioresistance by destabilizing KDM4C in lung cancer cells. Thus, our findings demonstrate that USP9X-mediated KDM4C deubiquitination activates TGF-β2/Smad signaling to promote radioresistance, suggesting that targeting KDM4C may be a promising radiosensitization strategy in the treatment of lung cancer.


2020 ◽  
Vol 52 (9) ◽  
pp. 1007-1015
Author(s):  
Zhe Zhang ◽  
Li Nong ◽  
Menglei Chen ◽  
Xiaoli Gu ◽  
Weiwei Zhao ◽  
...  

Abstract Vasculogenic mimicry (VM) refers to a new tubular network of the blood supply system with abundant extracellular matrix. VM is similar to capillaries but does not involve endothelial cells. As a traditional herbal medicine commonly used in China, baicalein possesses anti-inflammatory and lipoxygenase activities. However, the effects of baicalein on the process of VM formation in non-small cell lung cancer (NSCLC) and the underlying mechanisms have remained poorly understood. In this study, baicalein was found to inhibit the viability and motility of A549 cells and induced the breakage of the cytoskeletal actin filament network. In addition, baicalein significantly decreased the formation of VM and downregulated the expressions of VM-associated factors, such as VE-cadherin, EphA2, MMP14, MMP2, MMP9, PI3K and LAMC2, similar to the effects of ROCK inhibitors. Indeed, baicalein inhibited RhoA/ROCK expression in vitro and in vivo, suggesting the underlying mechanisms of reduced VM formation. Collectively, baicalein suppressed the formation of VM in NSCLC by targeting the RhoA/ROCK signaling pathway, indicating that baicalein might serve as an emerging drug for NSCLC.


2021 ◽  
Author(s):  
kunwei niu ◽  
Shibin Qu ◽  
Xuan Zhang ◽  
Jimin Dai ◽  
Jianlin Wang ◽  
...  

Abstract Background: Hepatocellular carcinoma (HCC) is often diagnosed at a late stage, when the prognosis is poor. The regulation of long non-coding RNAs (lncRNAs) plays a crucial role in HCC. However, the precise regulatory mechanisms of lncRNA signaling in HCC remain largely unknown. We study aim to investigate the underlying mechanisms of lncRNA (upregulated in hepatocellular carcinoma) URHC in HCC. Methods: RT-qPCR, fluorescence in situ hybridization (FISH) staining, EdU, colony formation, and tumor xenografts experiments were used to identify localized and biological effects of URHC on HCC cells in vitro and in vivo. The bioinformatics analysis, Dual-luciferase reporter assay, and rescue experiments revealed the potential mechanism of URHC.Results: URHC silencing may inhibit the HCC cells proliferation in vitro and in vivo. We found that URHC was mainly localized in the cytoplasm. The expression of miR-5007-3p was negatively regulated by URHC. And miR-5007-3p could reverse the effect of URHC in HCC cells. The expression of DNAJB9 was negatively regulated by miR-5007-3p but positively regulated by URHC. These suggesting of lncRNA-URHC positively regulated the level of DNAJB9 by sponging miR-5007-3p.Conclusion: Together, our study elucidated the role of URHC as a miRNA sponge in HCC, and shed new light on lncRNA-directed diagnostics and therapeutics in HCC.


2006 ◽  
Vol 26 (6) ◽  
pp. 2273-2285 ◽  
Author(s):  
Tatsuji Fujiwara ◽  
Yasutake Mori ◽  
Dong Ling Chu ◽  
Yoshihisa Koyama ◽  
Shingo Miyata ◽  
...  

ABSTRACT HuD is an RNA-binding protein that has been shown to induce neuronal differentiation by stabilizing labile mRNAs carrying AU-rich instability elements. Here, we show a novel mechanism of arginine methylation of HuD by coactivator-associated arginine methyltransferase 1 (CARM1) that affected mRNA turnover of p21cip1/waf1 mRNA in PC12 cells. CARM1 specifically methylated HuD in vitro and in vivo and colocalized with HuD in the cytoplasm. Inhibition of HuD methylation by CARM1 knockdown elongated the p21cip1/waf1 mRNA half-life and resulted in a slow growth rate and robust neuritogenesis in response to nerve growth factor (NGF). Methylation-resistant HuD bound more p21cip1/waf1 mRNA than did the wild type, and its overexpression upregulated p21cip1/waf1 protein expression. These results suggested that CARM1-methylated HuD maintains PC12 cells in the proliferative state by committing p21cip1/waf1 mRNA to its decay system. Since the methylated population of HuD was reduced in NGF-treated PC12 cells, downregulation of HuD methylation is a possible pathway through which NGF induces differentiation of PC12 cells.


2020 ◽  
Author(s):  
kunwei niu ◽  
Shibin Qu ◽  
Xuan Zhang ◽  
Jimin Dai ◽  
Jianlin Wang ◽  
...  

Abstract Background: To investigate the underlying mechanisms of lncRNA URHC in HCC. Methods: RT-qPCR, FISH staining, EdU, colony formation, and tumor xenografts experiments were used to identify localized and biological effects of URHC on HCC cells in vitro and in vivo. The Bioinformatics analysis, Dual- luciferase reporter assay, and rescue experiments revealed the potential mechanism of URHC. Results: We found that URHC was mainly localized in the cytoplasm. URHC silencing may inhibit the HCC cells proliferation. And URHC positively regulated the level of DNAJB9 by sponging miR-5007-3p. Conclusion: Together, our study elucidated the role of URHC as a miRNA sponge in HCC, and shed new light on lncRNA-directed diagnostics and therapeutics in HCC.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Kunwei Niu ◽  
Shibin Qu ◽  
Xuan Zhang ◽  
Jimin Dai ◽  
Jianlin Wang ◽  
...  

Background. Hepatocellular carcinoma (HCC) is often diagnosed at a late stage, when the prognosis is poor. The regulation of long noncoding RNAs (lncRNAs) plays a crucial role in HCC. However, the precise regulatory mechanisms of lncRNA signaling in HCC remain largely unknown. Our study aims to investigate the underlying mechanisms of lncRNA (upregulated in hepatocellular carcinoma) URHC in HCC. Objective. To study the in vivo and in vitro localization and biological effects of URHC on liver cancer cells. Through bioinformatics analysis, dual-luciferase reporter gene analysis and rescue experiments revealed the possible mechanism of URHC. Methods. RT-qPCR, fluorescence in situ hybridization (FISH) staining, EdU, colony formation, and tumor xenograft experiments were used to identify localized and biological effects of URHC on HCC cells in vitro and in vivo. The bioinformatics analysis, dual-luciferase reporter assay, and rescue experiments revealed the potential mechanism of URHC. Results. URHC silencing may inhibit the HCC cells’ proliferation in vitro and in vivo. We found that URHC was mainly localized in the cytoplasm. The expression of miR-5007-3p was negatively regulated by URHC. And miR-5007-3p could reverse the effect of URHC in HCC cells. The expression of DNAJB9 was negatively regulated by miR-5007-3p but positively regulated by URHC. These suggestive of lncRNA-URHC positively regulated the level of DNAJB9 by sponging miR-5007-3p. Conclusion. Together, our study elucidated the role of URHC as a miRNA sponge in HCC and shed new light on lncRNA-directed diagnostics and therapeutics in HCC.


2021 ◽  
Vol 9 (9) ◽  
pp. e002408
Author(s):  
Clément Anfray ◽  
Francesco Mainini ◽  
Elisabeth Digifico ◽  
Akihiro Maeda ◽  
Marina Sironi ◽  
...  

BackgroundTumor-associated macrophages (TAMs) play a key immunosuppressive role that limits the ability of the immune system to fight cancer and hinder the antitumoral efficacy of most treatments currently applied in the clinic. Previous studies have evaluated the antitumoral immune response triggered by (TLR) agonists, such as poly(I:C), imiquimod (R837) or resiquimod (R848) as monotherapies; however, their combination for the treatment of cancer has not been explored. This study investigates the antitumoral efficacy and the macrophage reprogramming triggered by poly(I:C) combined with R848 or with R837, versus single treatments.MethodsTLR agonist treatments were evaluated in vitro for toxicity and immunostimulatory activity by Alamar Blue, ELISA and flow cytometry using primary human and murine M-CSF-differentiated macrophages. Cytotoxic activity of TLR-treated macrophages toward cancer cells was evaluated with an in vitro functional assay by flow cytometry. For in vivo experiments, the CMT167 lung cancer model and the MN/MCA1 fibrosarcoma model metastasizing to lungs were used; tumor-infiltrating leukocytes were evaluated by flow cytometry, RT-qPCR, multispectral immunophenotyping, quantitative proteomic experiments, and protein–protein interaction analysis.ResultsResults demonstrated the higher efficacy of poly(I:C) combined with R848 versus single treatments or combined with R837 to polarize macrophages toward M1-like antitumor effectors in vitro. In vivo, the intratumoral synergistic combination of poly(I:C)+R848 significantly prevented tumor growth and metastasis in lung cancer and fibrosarcoma immunocompetent murine models. Regressing tumors showed increased infiltration of macrophages with a higher M1:M2 ratio, recruitment of CD4+ and CD8+ T cells, accompanied by a reduction of immunosuppressive CD206+ TAMs and FOXP3+/CD4+ T cells. The depletion of both CD4+ and CD8+ T cells resulted in complete loss of treatment efficacy. Treated mice acquired systemic antitumoral response and resistance to tumor rechallenge mediated by boosted macrophage cytotoxic activity and T-cell proliferation. Proteomic experiments validate the superior activation of innate immunity by poly(I:C)+R848 combination versus single treatments or poly(I:C)+R837, and protein–protein-interaction network analysis reveal the key activation of the STAT1 pathway.DiscussionThese findings demonstrate the antitumor immune responses mediated by macrophage activation on local administration of poly(I:C)+R848 combination and support the intratumoral application of this therapy to patients with solid tumors in the clinic.


2021 ◽  
Vol 11 (12) ◽  
pp. 2395-2400
Author(s):  
Yue-Jiao Cao ◽  
Zhi-Peng Li ◽  
Nan Zhou ◽  
Jia-Ping Liu

The cis-platinum (CDDP) is a first line chemotherapeutics drugs to combat lung cancer. However, its efficacy is largely limited due to the off-target delivery and multidrug resistance (MDR) upon in vivo applications. In order to solve this problem, here in our study, we prepared ultra-small lipidpolymer nanoparticles (USLPNPs) using one-pot method and to load CDDP (USLPNPs-CDDP) for the effective lung cancer therapy. Our results showed that the size of USLPNPs-CDDP was 20 nm and the stability of this platform was high. The sustained drug release afforded the long-lasting administration of CDDP to treat cancers. Most importantly, the USLPNPs-CDDP was able to bypass the CDDP resistance of A549/CDDP cells, which resulted in better anticancer benefits as compared to free CDDP both in vitro and in vivo.


2017 ◽  
Vol 44 (4) ◽  
pp. 1311-1324 ◽  
Author(s):  
Qian Fan ◽  
Xiuting Hu ◽  
Haiyang Zhang ◽  
Shengguang Wang ◽  
Huilai Zhang ◽  
...  

Background/Aims: MicroRNAs (miRNAs) have emerged as major regulators of tumour development and progression in non-small cell lung cancer (NSCLC). However, the role of miR-193a-3p in NSCLC is still unclear. Methods: Quantitative RT-PCR was used to detect miR-193a-3p expression levels in NSCLC tumour tissues. CCK8, EdU and cell migration assays were performed to analyse the biological functions of miR-193a-3p in NSCLC cells. Luciferase reporter assays were used to validate the bioinformatics-predicted target genes of miR-193a-3p. Western blotting and RNA/DNA interference carried out to evaluate the association between miR-193a-3p and KRAS. Results: miR-193a-3p expression was decreased in the NSCLC tumour tissues. We investigated the biological effects of miR-193a-3p both in vivo and in vitro and found that enforced expression of miR-193a-3p inhibited tumour formation and suppressed cell proliferation and cell migration. KRAS was found to be a potential target of miR-193a-3p, and dual luciferase reporter assays showed that miR-193a-3p directly binds to the 3’-untranslated region (3’-UTR) of KRAS mRNA. In addition, we found that changing the expression of KRAS had the opposite results to those induced by miR-193a-3p in the NSCLC cells. Importantly, simultaneous overexpression of miR-193a-3p and KRAS could counteract the effects of both on cellular functions. Conclusion: These findings highlight an important role for miR-193a-3p as a tumour suppressor in NSCLC pathogenesis via the regulation of KRAS expression.


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