scholarly journals Silybin suppresses cell proliferation and induces apoptosis of multiple myeloma cells via the PI3K/Akt/mTOR signaling pathway

2016 ◽  
Vol 13 (4) ◽  
pp. 3243-3248 ◽  
Author(s):  
NAN FENG ◽  
JIANMIN LUO ◽  
XIMIN GUO
Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1870-1870
Author(s):  
Yanyan Gu ◽  
Jonathan L. Kaufman ◽  
Lawrence H. Boise ◽  
Sagar Lonial

Abstract Abstract 1870 Introduction: The development and survival of normal plasma cells as well as multiple myeloma cells depend on an elaborately regulated ubiquitin proteasome system (UPS). Proteasome inhibitors such as bortezomib have proved to be highly active in the treatment of multiple myeloma. MLN4924, a newly developed investigational NEDD8 activating enzyme (NAE) inhibitor, exhibits promising anti-tumor effect through both clinical and laboratory observation. We sought to evaluate the individual signaling effects of MLN4924 in multiple myeloma, with the intent of further understanding the mechanism of action and identifying potential combinations. Methods: Human myeloma cell lines (MM.1S, MM.1R and U266) were treated with increasing concentrations of MLN4924 for 24, 48 and 72 hrs respectively or concurrently with bortezomib. Cell viability (MTT), apoptosis, western blot, RT-qPCR and siRNA assays were used to identify the cellular and molecular sequelae of MLN4924 treatment. Results: Single agent studies demonstrate that MLN4924 induces cytotoxicity in all three MM cell lines. Cytotoxicity is associated with increased apoptosis and suppression of AKT and mTOR signaling pathway, as detected by FACS and western blot. MLN4924 suppresses protein turnover of Cullin-ring ligases substrates leading to stabilization of specific proteins, such as p27, CDT1, NRF2. We find that REDD1, a substrate of CUL4 A–DDB 1–ROC1–β-TRCP ubiquitin ligase and negative regulator of mTOR pathway, increases in as early as 2 hours when treated with MLN4924. Knock-down of REDD1 using siRNA alleviates MLN4924 induced AKT, mTOR signaling suppression as well as the growth inhibition, which suggests that MLN4924 inhibits AKT, mTOR signaling through upregulating REDD1 protein leading to cytotoxicity. Combining MLN4924 with bortezomib synergistically enhances the antitumor effect of MLN4924. Western blot confirms the development of significantly increased procaspase and PARP cleavage, as well as substantial down regulation of AKT and mTOR signaling. Neither IL-6 nor IGF-1 is able to abrogate these combination effects. When we silence REDD1 in the combination assay in MM.1R, we find less cell apoptosis and suppression of AKT, mTOR pathway, which further support that REDD1 is an important regulator for MLN4924 induced cytotoxicity in MMs. Conclusion: MLN4924 is a potent investigational antitumor compound suppressing mTOR signaling pathways in myeloma cell lines. Down-regulation of the mTOR signaling pathway is associated with increased expression of REDD1. Combination of MLN4924 with the proteasome inhibitor bortezomib induces synergistic apoptosis in MMs cell lines which can overcome the prosurvival effects of growth factor (IL-6 and IGF-1). These findings could positively impact clinical combination strategies. Disclosures: Kaufman: Millenium: Consultancy; Onyx Pharmaceuticals: Consultancy; Novartis: Consultancy; Keryx: Consultancy; Merck: Research Funding; Celgene: Research Funding. Lonial:Millennium Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy; Novartis: Consultancy; Bristol-Myers Squibb: Consultancy; Onyx: Consultancy; Merck: Consultancy.


2021 ◽  
Vol 20 ◽  
pp. 153303382199007
Author(s):  
Wenlin Liu ◽  
Jiandong Zhan ◽  
Rong Zhong ◽  
Rui Li ◽  
Xiaoli Sheng ◽  
...  

Background: Laryngeal cancer is one of the most common malignant tumors among head and neck cancers. Accumulating studies have indicated that long noncoding RNAs (lncRNAs) play an important role in laryngeal cancer occurrence and progression, however, the functional roles and relative regulatory mechanisms of lncRNA growth arrest-specific transcript 5 (GAS5) in laryngeal cancer progression remain unclear. Methods: The expression of lncRNA GAS5 in both laryngeal cancer tissues and cell lines was evaluated using quantitative reverse transcription-polymerase chain reaction (RT-qPCR) assay. The relationships between lncRNA GAS5 expression and clinical parameters were also analyzed. To determine the biological function of lncRNA GAS5, a lncRNA GAS5-specific plasmid was first transfected into laryngeal cancer cells using lentiviral technology. Cell counting kit-8 assay, flow cytometry, and Transwell assays were used to detect in vitro cell proliferation, apoptosis, cycle distribution, and metastasis abilities, respectively. Furthermore, in vivo cell growth experiments were also performed using nude mice. Additionally, western blotting was performed to identify the underlying regulatory mechanism. Results: In the current study, lncRNA GAS5 was downregulated in laryngeal cancer tissues and its low expression was closely associated with poor tumor differentiation, advanced TNM stage, lymph node metastasis, and shorter overall survival time. In addition, lncRNA GAS5 upregulation significantly inhibited laryngeal cancer cell proliferation both in vitro and in vivo. Moreover, in response to lncRNA GAS5 overexpression, more laryngeal cancer cells were arrested at the G2/M stage, accompanied by increased cell apoptosis rates and suppressed migration and invasion capacities. Mechanistically, our data showed that the overexpression of lncRNA GAS5 significantly regulated the PI3K/AKT/mTOR signaling pathway. Conclusion: LncRNA GAS5 might act as a suppressor gene during laryngeal cancer development, as it suppressed cell proliferation and metastasis by regulating the PI3K/AKT/mTOR signaling pathway; thus, lncRNA GAS5 is a promising therapeutic biomarker for the treatment of laryngeal cancer.


Tumor Biology ◽  
2017 ◽  
Vol 39 (5) ◽  
pp. 101042831769756 ◽  
Author(s):  
Hui Shi ◽  
Jin Pu ◽  
Xiao-Li Zhou ◽  
Yun-Ye Ning ◽  
Chong Bai

This study aimed to investigate the effects of long non-coding RNA ROR (regulator of reprogramming) on cisplatin (DDP) resistance in patients with non-small-cell lung cancer by regulating PI3K/Akt/mTOR signaling pathway. Human cisplatin-resistant A549/DDP cell lines were selected and divided into control group, negative control group, si-ROR group, ROR over-expression group, Wortmannin group, and ROR over-expression + Wortmannin group. MTT assay was used to determine the optimum inhibitory concentration of DDP. Quantitative real-time polymerase chain reaction and western blotting were applied to detect expressions of long non-coding RNA ROR, PI3K, Akt, and mTOR. Colony-forming assay, scratch test, Transwell assay, and flow cytometry were conducted to detect cell proliferation, migration, invasion, and apoptosis, respectively. Tumor-formation assay was performed to detect the growth of transplanted tumors. Long non-coding RNA ROR expression was high in human A549/DDP cell lines. Compared with the control and negative control groups, the mRNA and protein expressions of PI3K, Akt, mTOR, and bcl-2 decreased, whereas the mRNA and protein expression of bax and the sensitivity of cells to DDP significantly increased. Cell proliferation, migration, and invasion abilities decreased in the si-ROR and Wortmannin groups. In comparison with control and negative control groups, the mRNA and protein expressions of PI3K, Akt, mTOR, and bcl-2 increased, whereas the mRNA and protein expressions of bax decreased, the sensitivity of cells to DDP significantly increased, and cell proliferation, migration, and invasion abilities decreased in the ROR over-expression group. For nude mice in tumor-formation assay, compared with control and negative control groups, the tumor weight was found to be lighter (1.03 ± 0.15) g, the protein expressions of PI3K, Akt, mTOR, and bcl-2 decreased, and the protein expression of bax increased in the si-ROR group. Long non-coding RNA ROR may affect the sensitivity of lung adenocarcinoma cells to DDP by targeting PI3K/Akt/mTOR signaling pathway.


2018 ◽  
Vol 32 ◽  
pp. 205873841881434 ◽  
Author(s):  
Genglong Zhu ◽  
Xialei Liu ◽  
Haijing Li ◽  
Yang Yan ◽  
Xiaopeng Hong ◽  
...  

Liver cancer is one of the most common and lethal cancers in human digestive system, which kills more than half a million people every year worldwide. This study aimed to investigate the effects of kaempferol, a flavonoid compound isolated from vegetables and fruits, on hepatic cancer HepG2 cell proliferation, migration, invasion, and apoptosis, as well as microRNA-21 (miR-21) expression. Cell viability was detected using cell counting kit-8 (CCK-8) assay. Cell proliferation was measured using 5-bromo-2′-deoxyuridine (BrdU) incorporation assay. Cell apoptosis was assessed using Guava Nexin assay. Cell migration and invasion were determined using two-chamber migration (invasion) assay. Cell transfection was used to change the expression of miR-21. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to analyze the expressions of miR-21 and phosphatase and tensin homologue (PTEN). Expression of key proteins involved in proliferation, apoptosis, migration, invasion, and phosphatidylinositol 3-kinase/protein kinase 3/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway were evaluated using western blotting. Results showed that kaempferol significantly inhibited HepG2 cell proliferation, migration, and invasion, and induced cell apoptosis. Kaempferol remarkably reduce the expression of miR-21 in HepG2 cells. Overexpression of miR-21 obviously reversed the effects of kaempferol on HepG2 cell proliferation, migration, invasion, and apoptosis. Moreover, miR-21 negatively regulated the expression of PTEN in HepG2 cells. Kaempferol enhanced the expression of PTEN and inactivated PI3K/AKT/mTOR signaling pathway in HepG2 cells. In conclusion, kaempferol inhibited proliferation, migration, and invasion of HepG2 cells by down-regulating miR-21 and up-regulating PTEN, as well as inactivating PI3K/AKT/mTOR signaling pathway.


2015 ◽  
Vol 79 (2) ◽  
pp. 101-109 ◽  
Author(s):  
Wei Xing ◽  
Wei Guo ◽  
Cun-Hua Zou ◽  
Ting-Ting Fu ◽  
Xiang-Yun Li ◽  
...  

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