scholarly journals mTORC2 promotes cell survival through c-Myc–dependent up-regulation of E2F1

2015 ◽  
Vol 211 (1) ◽  
pp. 105-122 ◽  
Author(s):  
Zhipeng Zou ◽  
Juan Chen ◽  
Anling Liu ◽  
Xuan Zhou ◽  
Qiancheng Song ◽  
...  
Keyword(s):  
Cell Survival ◽  
Tumor Model ◽  
Xenograft Tumor ◽  
In Vivo Experiments ◽  
Xenograft Tumor Model ◽  
Cancer Cell Survival ◽  
Consequent Reduction ◽  
Dependent Mechanism

Previous studies have reported that mTORC2 promotes cell survival through phosphorylating AKT and enhancing its activity. We reveal another mechanism by which mTORC2 controls apoptosis. Inactivation of mTORC2 promotes binding of CIP2A to PP2A, leading to reduced PP2A activity toward c-Myc serine 62 and, consequently, enhancement of c-Myc phosphorylation and expression. Increased c-Myc activity induces transcription of pri-miR-9-2/miR-9-3p, in turn inhibiting expression of E2F1, a transcriptional factor critical for cancer cell survival and tumor progression, resulting in enhanced apoptosis. In vivo experiments using B cell–specific mTORC2 (rapamycin-insensitive companion of mTOR) deletion mice and a xenograft tumor model confirmed that inactivation of mTORC2 causes up-regulation of c-Myc and miR-9-3p, down-regulation of E2F1, and consequent reduction in cell survival. Conversely, Antagomir-9-3p reversed mTORC1/2 inhibitor–potentiated E2F1 suppression and resultant apoptosis in xenograft tumors. Our in vitro and in vivo findings collectively demonstrate that mTORC2 promotes cell survival by stimulating E2F1 expression through a c-Myc– and miR-9-3p–dependent mechanism.

scholarly journals A Novel Anti-EGFR mAb Ame55 with Lower Toxicity and Better Efficacy than Cetuximab When Combined with Irinotecan

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Weiyi Qiu ◽  
Chang Zhang ◽  
Shuang Wang ◽  
Xiaoyan Yu ◽  
Qiong Wang ◽  
...  
Keyword(s):  
Tumor Model ◽  
Phage Library ◽  
Lovo Cell ◽  
Xenograft Tumor ◽  
Cynomolgus Monkeys ◽  
Lower Affinity ◽  
Egfr Inhibition ◽  
Xenograft Tumor Model

To improve efficacy and minimize toxicity of EGFR inhibition treatment, we developed Ame55, a novel anti-EGFR IgG1 with lower affinity to EGFR than cetuximab (C225) from a human phage library. Ame55 had lower bioactivity than cetuximab in vitro but similar antitumor efficacy as cetuximab in vivo. Moreover, Ame55 was more efficacious than cetuximab in a Lovo cell xenograft tumor model when combined with irinotecan (CPT-11). Ame55 concentrates in the mouse xenograft tumor and has less toxicity than cetuximab in cynomolgus monkeys in an overdose study.

scholarly journals LncRNA SNHG15 regulates osteosarcoma progression in vitro and in vivo via sponging miR-346 and regulating TRAF4 expression

2020 ◽  
Vol 15 (1) ◽  
pp. 423-436
Author(s):  
Xuewu Chen ◽  
Hongguang Xu
Keyword(s):  
Binding Sites ◽  
Biological Function ◽  
Tumor Model ◽  
Xenograft Tumor ◽  
Positive Effects ◽  
Xenograft Tumor Model ◽  
Nucleolar Rna ◽  
Common Primary Malignant Bone

AbstractOsteosarcoma (OS) is a common primary malignant bone tumor around the world. It has been reported that long noncoding RNAs (lncRNAs) take part in diverse pathological processes of OS; however, the mechanism remains unknown. This study aimed to uncover the profile of lncRNA small nucleolar RNA host gene 15 (SNHG15), its biological function, and its potential involvement in the mechanism of OS progression in vitro and in vivo. The expression of SNHG15 and TRAF4 was promoted in OS tissues opposite for that of miR-346. The silencing of SNHG15 limited the proliferation, invasion, and enhanced apoptosis of SaoS2 and HOS cells. Moreover, the putative binding sites between miR-346 and SNHG15 or TRAF4 were predicted by starBase and Targetscan software online, individually. Also, miR-346 deletion reversed the positive effects of SNHG15 elimination on proliferation, apoptosis, and invasion in cells. In addition, the upregulation of TRAF4 disrupted the biofunctional results from miR-346 promotion subsequently. Finally, SNHG15 knockdown repressed OS tumor growth in a xenograft tumor model. SNHG15 enhanced the progression of OS by regulating the miR-346/TRAF4 axis in vitro and in vivo.

scholarly journals Combining Sodium Butyrate With Cisplatin Increases the Apoptosis of Gastric Cancer In Vivo and In Vitro via the Mitochondrial Apoptosis Pathway

2021 ◽  
Vol 12 ◽  
Author(s):  
Yangbo Li ◽  
Pengzhan He ◽  
Yinghui Liu ◽  
Mingming Qi ◽  
Weiguo Dong
Keyword(s):  
Sodium Butyrate ◽  
Intestinal Flora ◽  
Tumor Model ◽  
Mitochondrial Apoptosis ◽  
Xenograft Tumor ◽  
Mouse Xenograft ◽  
Xenograft Tumor Model ◽  
Related Pathway

Introduction: The gastrointestinal malignancy, gastric cancer (GC), has a high incidence worldwide. Cisplatin is a traditional chemotherapeutic drug that is generally applied to treat cancer; however, drug tolerance affects its efficacy. Sodium butyrate is an intestinal flora derivative that has general anti-cancer effects in vitro and in vivo via pro-apoptosis effects and can improve prognosis in combination with traditional chemotherapy drugs. The present study aimed to assess the effect of sodium butyrate combined with cisplatin on GC.Methods: A Cell Counting Kit-8 assay was used to assess the viability of GC cells in vitro. Hoechst 33,258 staining and Annexin V-Phycoerythrin/7-Aminoactinomycin D were used to qualitatively and quantitatively detect apoptosis in GC cells. Intracellular reactive oxygen species (ROS) measurement and a mitochondrial membrane potential (MMP) assay kit were used to qualitatively and quantitatively reflect the function of mitochondria in GC cells. Western blotting was used to verify the above experimental results. A nude mouse xenograft tumor model was used to evaluate the anti-tumor efficacity of sodium and cisplatin butyrate in vivo.Results: Cisplatin combined with sodium butyrate increased the apoptosis of GC cells. In the nude mouse xenograft tumor model, sodium butyrate in combination with cisplatin markedly inhibited the growth of the tumor more effectively than either single agent. The combination of sodium butyrate and cisplatin increased the intracellular ROS, decreased the MMP, and suppressed the invasion and migration abilities of GC cells. Western blotting verified that the combination of sodium butyrate and cisplatin remarkably enhanced the levels of mitochondrial apoptosis-related pathway proteins.Conclusion: Sodium butyrate, a histone acetylation inhibitor produced by intestinal flora fermentation, combined with cisplatin enhanced the apoptosis of GC cells through the mitochondrial apoptosis-related pathway, which might be considered as a therapeutic option for GC.

scholarly journals Osteoblast-Derived Paracrine and Juxtacrine Signals Protect Disseminated Breast Cancer Cells from Stress

Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1366
Author(s):  
Russell Hughes ◽  
Xinyue Chen ◽  
Natasha Cowley ◽  
Penelope D. Ottewell ◽  
Rhoda J. Hawkins ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Survival ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Breast Cancer Cells ◽  
Metastatic Breast ◽  
Accessory Cell ◽  
Cancer Cell Survival

Metastatic breast cancer in bone is incurable and there is an urgent need to develop new therapeutic approaches to improve survival. Key to this is understanding the mechanisms governing cancer cell survival and growth in bone, which involves interplay between malignant and accessory cell types. Here, we performed a cellular and molecular comparison of the bone microenvironment in mouse models representing either metastatic indolence or growth, to identify mechanisms regulating cancer cell survival and fate. In vivo, we show that regardless of their fate, breast cancer cells in bone occupy niches rich in osteoblastic cells. As the number of osteoblasts in bone declines, so does the ability to sustain large numbers of breast cancer cells and support metastatic outgrowth. In vitro, osteoblasts protected breast cancer cells from death induced by cell stress and signaling via gap junctions was found to provide important juxtacrine protective mechanisms between osteoblasts and both MDA-MB-231 (TNBC) and MCF7 (ER+) breast cancer cells. Combined with mathematical modelling, these findings indicate that the fate of DTCs is not controlled through the association with specific vessel subtypes. Instead, numbers of osteoblasts dictate availability of protective niches which breast cancer cells can colonize prior to stimulation of metastatic outgrowth.

scholarly journals Circular RNA_CNST Promotes the Tumorigenesis of Osteosarcoma Cells by Sponging miR-421

2020 ◽  
Vol 29 ◽  
pp. 096368972092614
Author(s):  
Ji-Hai Wang ◽  
Xue-Jian Wu ◽  
Yong-Zhuang Duan ◽  
Feng Li
Keyword(s):  
Colony Formation ◽  
Specific Binding ◽  
Tumor Model ◽  
Gene Expression Omnibus ◽  
Pcr Analysis ◽  
Circular Rnas ◽  
Xenograft Tumor ◽  
Potential Biomarker

Circular RNAs (circRNAs) act crucial roles in the progression of multiple malignancies including osteosarcoma (OS). But, the underlying mechanisms by which hsa_circ_0017311 (circCNST) contributes to the tumorigenesis of OS remain poorly understood. Our present study aimed to explore the role and mechanisms of circCNST in OS tumorigenesis. The differentially expressed circRNAs were identified by the Gene Expression Omnibus database. The association of circCNST with clinicopathological features and prognosis in patients with OS was analyzed by RNA fluorescence in situ hybridization (FISH) and quantitative real-time polymerase chain reaction (PCR) analysis. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), colony formation assays, and a xenograft tumor model were conducted to assess the role of circCNST in OS cells in vitro and in vivo. CircCNST-specific binding with miR-421 was confirmed by FISH, luciferase gene report, and RNA immunoprecipitation assays. As a result, we found that the expression levels of circCNST were dramatically increased in OS tissues and cell lines as compared with the adjacent normal tissues, and it was associated with tumor size and poor survival in OS patients. Knockdown of circCNST repressed cell viability, colony formation, and xenograft tumor growth, while restored expression of circCNST reversed these effects. Furthermore, circCNST was colocalized with miR-421 in the cytoplasm and acted as a sponge of miR-421, which attenuated circCNST-induced proliferation-promoting effects in OS cells by targeting SLC25A3. In conclusion, our findings demonstrate that circCNST promotes the tumorigenesis of OS cells by sponging miR-421, and provides a potential biomarker for patients with OS.

scholarly journals Circular RNA circ-CDYL sponges miR-1180 to elevate yes-associated protein in multiple myeloma

2020 ◽  
Vol 245 (11) ◽  
pp. 925-932 ◽  
Author(s):  
Fang Chen ◽  
Xiaohui Wang ◽  
Shuang Fu ◽  
Shaokun Wang ◽  
Yu Fu ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Tumor Model ◽  
Circular Rna ◽  
Xenograft Tumor ◽  
Functional Assays ◽  
Xenograft Tumor Model ◽  
Therapeutic Possibility ◽  
Plasma Depletion ◽  
Potential Therapeutic Intervention

The covalently closed circular RNA has recently been proposed as a pivotal player in tumorigenesis. In the current study, we found that circ-CDYL was notably elevated in multiple myeloma tissue and plasma samples and had good diagnostic and prognostic efficacy. Functional assays showed that circ-CDYL enhanced the viability and DNA synthesis of multiple myeloma cells and inhibited apoptosis. Mechanically, cytoplasmic circ-CDYL was co-localized with miR-1180, and circ-CDYL absorbed miR-1180 to upregulate yes-associated protein (YAP), thereby facilitating multiple myeloma progression. Importantly, we further confirmed the existence of this circ-CDYL/miR-1180/YAP regulatory axis in vivo by using the xenograft tumor model. Taken together, our data demonstrate that circ-CDYL is novel promoter of multiple myeloma, and targeting circ-CDYL and its associated network implicates the therapeutic possibility for multiple myeloma patients. Impact statement Multiple myeloma (MM) is an extremely complex and heterogeneous disease, and its pathogenesis is poorly understood. Here, we described an important MM-related circular RNA (circRNA), circ-CDYL. It was remarkably increased in both MM cells and plasma. Depletion of circ-CDYL evidently stunted MM growth. Circ-CDYL could absorb miR-1180 and alleviated the repression of miR-1180 on YAP, leading to increased YAP expression, ultimately triggering MM uncontrolled growth. Therefore, our findings advance the understanding of MM pathogenesis, and also raise the possibility of considering circ-CDYL as a potential therapeutic intervention for MM.

scholarly journals ATM inhibition drives metabolic adaptation via induction of macropinocytosis

2020 ◽  
Author(s):  
Chi-Wei Chen ◽  
Raquel Buj ◽  
Erika S. Dahl ◽  
Kelly E. Leon ◽  
Erika L. Varner ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Survival ◽  
Cancer Cell ◽  
Metabolic Reprogramming ◽  
Metabolic Adaptation ◽  
Dependent Manner ◽  
Cancer Cell Survival ◽  
Branched Chain

SummaryMacropinocytosis is a nonspecific endocytic process that enhances cancer cell survival under nutrient-poor conditions. Ataxia-Telangiectasia mutated (ATM) is a tumor suppressor that plays a role in cellular metabolic reprogramming. We report that suppression of ATM increases macropinocytosis in an AMPK-dependent manner to promote cancer cell survival in nutrient-poor conditions. Combined inhibition of ATM and macropinocytosis suppressed proliferation and induced cell death both in vitro and in vivo. Metabolite analysis of the ascites and interstitial fluid from tumors indicated decreased branched chain amino acids (BCAAs) in the microenvironment of ATM-inhibited tumors. Supplementation of ATM inhibitor-treated cells with BCAAs abrogated AMPK phosphorylation and macropinocytosis and rescued the cell death that occurs due to combined inhibition of ATM and macropinocytosis. These data reveal a novel molecular basis of ATM-mediated tumor suppression whereby loss of ATM promotes pro-tumorigenic uptake of nutrients to promote cancer cell survival and reveal a metabolic vulnerability of ATM-inhibited cells.

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