scholarly journals The mitochondrial deubiquitinase USP30 regulates AKT/mTOR signaling

2021 ◽  
Author(s):  
Ruohan Zhang ◽  
Judith Krigman ◽  
Serra Ozgen ◽  
Hongke Luo ◽  
Yutong Zhao ◽  
...  

Mitophagy is an intracellular mechanism to maintain mitochondrial health by removing dysfunctional mitochondria. The E3 ligase Parkin ubiquitinates the membrane proteins on targeted mitochondria to initiate mitophagy, and USP30 antagonizes this Parkin-dependent mitophagy. AKT/mTOR signaling is a master regulator of cell proliferation, differentiation, survival, and growth. Although mounting evidence showed mitophagy and AKT/mTOR signaling interact with each other during mitophagy, the specific mechanisms between Parkin/USP30 and AKT/mTOR signaling have not been elucidated. This research artificially expressed Parkin and USP30 in Hela cells and compared AKT/mTOR and apoptosis signals between Hela cells, HeLa Parkin cells, and Hela Parkin USP30 cells during mitophagy. The study results suggest that Parkin promotes AKT degradation via ubiquitination, which induces cell apoptosis during mitochondrial stress. On the contrary, USP30 protects AKT via deubiquitination. These findings provide new insights into the roles of Parkin and USP30 in cell apoptosis and physiological and pathological functions of USP30 beyond mitophagy.

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.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jianwen Long ◽  
Xianming Pi

To investigate whether Polyphyllin I (PPI) might induce the autophagy and apoptosis of melanoma cells by regulating PI3K/Akt/mTOR signal pathway. Melanoma A375 cells were incubated with different concentrations of Polyphyllin I (0, 1.5, 3.0, and 6.0 mg/L) and PI3K/Akt/mTOR signaling pathway activator IGF-1(20 mg/L). CCK-8 assay was utilized to detect cell proliferation; Cell apoptosis and cell cycle were measured by flow cytometry; Western blot was used to examine the expressions of proteins. Immunofluorescence analysis was performed to evaluate autophagy of A375 cells; In addition, xenograft-bearing nude mice were applied to study the role of Polyphyllin I on melanoma development, melanoma cell proliferation, as well as melanoma cell apoptosis in vivo. The outcomes represented that Polyphyllin I promoted A375 cell apoptosis via upregulating Bax level and cleaved caspase-3 level and downregulating Bcl-2 level, inhibited the growth of A375 cells at the G0/G1 phase, and enhanced cell autophagy via regulating the levels of Beclin 1, LC3II, and p62. However, IGF-1 (an activator of PI3K/Akt/mTOR signal pathway) attenuated these changes that Polyphyllin I induced. Furthermore, the xenograft model experiment confirmed that Polyphyllin I treatment suppressed xenograft tumor growth, increased apoptotic index evaluated by the TUNEL method, and reduced the level of Ki67 in tumor tissues in vivo. In conclusion, Polyphyllin I treatment enhanced melanoma cell autophagy and apoptosis, as well as blocked melanoma cell cycle via suppressing PI3K/Akt/mTOR signal pathway. Meanwhile, Polyphyllin I treatment suppressed the development of melanoma in vivo. Therefore, Polyphyllin I possibly is a promising molecular targeted agent used in melanoma therapy.


2018 ◽  
Vol 48 (1) ◽  
pp. 371-384 ◽  
Author(s):  
Guanghua Liu ◽  
Xin Zhao ◽  
Jingmin Zhou ◽  
Xiangming Cheng ◽  
Zixing Ye ◽  
...  

Background/Aims: Emerging evidence suggests that long non-coding RNAs (lncRNAs) play a vital regulatory role in the pathogenesis and progression of renal cell carcinoma (RCC). We aim to determine lncRNA profiles in clear cell RCC (ccRCC) and investigate key lncRNAs involved in ccRCC tumorigenesis and progression. Methods: RNA sequencing technique and qPCR were used to determine the candidate lncRNAs in ccRCC tissues. The correlations between lncRNA P73 antisense RNA 1T (TP73-AS1) levels and survival outcomes were analyzed to elucidate its clinical significance. The underlying mechanisms of TP73-AS1 in ccRCC were analyzed through in vitro functional assays. Results: We found TP73-AS1 was upregulated in 40 ccRCC tissues compared with adjacent normal renal tissues and increased TP73-AS1 was correlated to aggressive clinicopathologic features and unfavorable prognosis. Knockdown of TP73-AS1 suppressed cell proliferation, invasion and induced cell apoptosis. We also identified KISS-1 metastasis-suppressor (KISS1) was significantly upregulated in TP73-AS1 knockdown cells. Further, we revealed that TP73-AS1 suppressed KISS1 expression through the interaction with Enhancer of zeste homolog 2 (EZH2) and the specific binding to KISS1 gene promoter region. Knockdown of KISS1 partly reversed TP73-AS1 knockdown-induced inhibition of cell proliferation and promotion of apoptosis. We further determined that TP73-AS1 knockdown activated PI3K/Akt/mTOR signaling pathway, while overexpression of TP73-AS1 induced inhibition of PI3K/Akt/mTOR pathway and these effects could be partly abolished by overexpression of KISS1. Conclusion: In conclusion, we identified that TP73-AS1 as an oncogenic lncRNA in the development of ccRCC and a potential target for human renal carcinoma treatment.


2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Yaohua Fan ◽  
MingJian Fei ◽  
Yan Li ◽  
Zhenzhen Gao ◽  
Yuzhang Zhu ◽  
...  

Thyroid cancer (TC) is the most common endocrine malignant disease with a rising morbidity year by year. Accumulating studies have shown that microRNAs (miRNAs) play a regulatory role in the progression of various tumors, but the molecular regulatory mechanism of miR-196a-2 in TC is still unknown. qRT-PCR was employed to measure the expression of miR-196a-2 and NRXN1 mRNA in TC cells, while western blot was used to detect the protein expression of NRXN1. CCK-8, colony formation and flow cytometry assays were used to measure cell proliferation and apoptosis of TC cells. Dual-luciferase reporter gene assay was used to predict and verify the targeted binding relationship between miR-196a-2 and NRXN1. Our study results manifested that miR-196a-2 was dramatically overexpressed in cells of TC, while NRXN1 was lowly expressed. miR-196a-2 could promote cell proliferation and inhibit cell apoptosis of TC. Additionally, miR-196a-2 could also target and inhibit the expression of NRXN1. Silencing NRXN1 could reverse the inhibitory effect of miR-196a-2 downregulation on cell proliferation of TC, as well as the promoting effect on cell apoptosis. In a conclusion, we found that miR-196a-2 could promote cell proliferation and inhibit cell apoptosis of TC by targeting NRXN1. Therefore, miR-196a-2/NRXN1 is potential to be a molecular therapeutic target for TC.


2020 ◽  
Author(s):  
Kang Zhu ◽  
He Bai ◽  
Mingzhu Mu ◽  
Yuanyuan Xue ◽  
Zhao Duan

Abstract Background Given its crucial role in human malignancies, how Ring finger protein 6 (RNF6) functions in cervical cancer has yet to be elucidated. In our research, we explored the biological significance of RNF6 in cervical cancer HeLa cells and its possible regulatory mechanism. Methods The expression levels of RNF6 mRNA and protein in cervical cancer tissues and cells were both analyzed, the former by Gene Expression Profiling Interactive Analysis (GEPIA), and the latter by quantitative real-time PCR (qRT-PCR) and immunohistochemistry assays. In vitro cell proliferation was tested through MTT assay and flow cytometer was used to detected Cell apoptosis. The activation of ERK(extracellular signal regulated kinase) was explored by Western Blot. Results In the present research, we found that the expression of RNF6 was high in both primary tissues and cervical cancer cells. RNF6 could promote cervical cancer HeLa cells growth. Once knockdown of RNF6 in cervical cancer cells, cell proliferation could be suppressed and cell apoptosis was promoted. Moreover, its elevation had an adverse effect on the prognosis of cervical cancer. Further studies showed that ERK activation is one of the potential mechanisms. Conclusion These findings provided evidence that the up-regulated RNF6 could activate the MAPK/ERK pathway to regulate the cell growth in cervical cancer, which suggested that RNF6 could be a promising target for diagnosis and treatment for cervical cancer.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hong-Bo Li ◽  
Jun-Kai Chen ◽  
Ze-Xin Su ◽  
Qing-Lin Jin ◽  
Li-Wen Deng ◽  
...  

Abstract Background Osteosarcoma is the most common primary bone tumor in children and adolescents. However, some patients with osteosarcoma develop resistance to chemotherapy, leading to a poor clinical prognosis. Hence, effective therapeutic agents that can improve the response to chemotherapy drugs to improve the prognosis of patients with osteosarcoma are urgently needed. Cordycepin has recently emerged as a promising antitumor drug candidate. This study aims to explore the effect of cordycepin in suppressing osteosarcoma in vivo and in vitro and the synergistic effect of cordycepin combined with cisplatin and to demonstrate the underlying molecular mechanism. Methods CCK-8 assay was performed to investigate the inhibition effect of cordycepin combined with cisplatin in osteosarcoma cell lines. The colony formation and invasion abilities were measured by colony formation assay and Transwell assay. Osteosarcoma cells apoptosis was detected by flow cytometry. Western blot analysis were used to detect the expression of cell apoptosis-related proteins and AMPK and AKT/mTOR signaling pathway-related proteins. Finally, we performed the in vivo animal model to further explore whether cordycepin and cisplatin exert synergistic antitumor effects. Results Notably, we found that treatment with cordycepin inhibited cell proliferation, invasion, and induced apoptosis in osteosarcoma cells in vitro and in vivo. Moreover, the combination of cordycepin and cisplatin led to marked inhibition of osteosarcoma cell proliferation and invasion and promoted osteosarcoma cell apoptosis in vitro and in vivo. Mechanistically, we demonstrated that cordycepin enhanced the sensitivity of osteosarcoma cells to cisplatin by activating AMPK and inhibiting the AKT/mTOR signaling pathway. Conclusions In brief, this study provides comprehensive evidence that cordycepin inhibits osteosarcoma cell growth and invasion and induces osteosarcoma cell apoptosis by activating AMPK and inhibiting the AKT/mTOR signaling pathway and enhances the sensitivity of osteosarcoma cells to cisplatin, suggesting that cordycepin is a promising treatment for osteosarcoma.


2016 ◽  
Vol 38 (3) ◽  
pp. 1030-1039 ◽  
Author(s):  
Gang Wang ◽  
Chengzhong Cai ◽  
Lei Chen

Background/Aims: Thyroid carcinoma (TC) is a highly lethal malignant cancer and its carcinogenesis remains undetermined. Dysregulation of microRNAs (miRNAs) is well known to be involved in the development of various cancers, including TC, whereas a role of miR-3666 in the pathogenesis of TC has not been appreciated. Methods: We analyzed the levels of MET and miR-3666 in TC tissue and the relationship of miR-3666 levels with patients' prognosis. We then overexpressed miR-3666 by miRNA mimics transfection and inhibited miR-3666 by miRNA antisense transfection in TC cells. Cell survival and growth were analyzed by CCK-8 assay and MTT assay, respectively. Cell apoptosis and proliferation were analyzed by flow cytometry. Bioinformatics analyses were applied to predict miR-3666 targets, which was then confirmed using luciferase reporter assay. Results: We detected significantly higher levels of MET, and significantly lower levels of miR-3666 in TC tissue, compared to the adjacent non-tumor tissue. Moreover, the low miR-3666 levels were associated with poor survival of the patients. Overexpression of miR-3666 significantly inhibited cell growth, while depletion of miR-3666 increased cell growth in TC cells. Moreover, the effects of miR-3666 on cell growth appeared to result from alteration in cell proliferation, rather than changes in cell apoptosis. MiR-3666 was found to bind to the 3'-UTR of MET mRNA to inhibit its translation in TC cells. Conclusion: Reduced miR-3666 levels in TC tissue may promotes TC growth, possibly through MET-mediated cell proliferation.


2020 ◽  
Vol 40 (4) ◽  
Author(s):  
Liheng Liu ◽  
Haili Jiang ◽  
Xiaoxin Wang ◽  
Xin Wang ◽  
Liying Zou

Abstract Endometrial cancer (EC) is the most common gynecologic malignancy in world. It has been reported that the mutation rate of FBXW7 is frequent in EC, but the specific functions of FBXW7 remain unknown in EC. In the present study, we revealed the role and mechanism of FBXW7 in EC cells. Compared with adjacent nontumor tissues, the FBXW7 expression level was lower in EC tissues. However, the level of STYX was in contrast with the expression of FBXW7 in EC tissues. And STYX interacted with FBXW7 and then down-regulated its expression level in EC. Over-expression of FBXW7 inhibited cell proliferation and facilitated apoptosis in EC cells, whereas silencing FBXW7 acted an opposite effect on EC cells. And the process of FBXW7 participated the proliferation and apoptosis in EC was regulated by STYX. FBXW7 suppressed the expression of Notch pathway related protein, and further inhibited the phosphorylation of mTOR. In addition, we also found that mTOR activitor (MHY1485) and Notch activator (Jagged-1) reversed the effect of over-expressing FBXW7 on cell proliferation and cell apoptosis. And Notch inhibitor (DAPT) counteracted the impact of over-expressing STYX on cell proliferation and cell apoptosis. Collectively, the present study verified that STYX inhibited the expression level of FBXW7 in EC, and then promoted cell proliferation but suppressed apoptosis through Notch–mTOR signaling pathway, which promoted carcinogenesis and progression of EC.


2021 ◽  
Vol 11 (8) ◽  
pp. 1560-1564
Author(s):  
Minhong Luo ◽  
Hao Liu ◽  
Caiju Mo ◽  
Qiang Wu ◽  
Zhenwei Chen ◽  
...  

This study investigated whether GLP-1 affects islet β cells in high glucose and the possible mechanism. INS-1 cells are separated into group A (treated with 5.6 mmol/L glucose), group B (group A+100 nmo1/L liraglutide), group C (cells were cultured in 16.7 mmol/L glucose) and group D (group C+100 nmo1/L liraglutide) followed by analysis of cell activity by CCK-8, apoptosis by Hoechst staining, INS level by ELISA, AMPK/mTOR signaling protein level by immunoblotting and RT-PCR. Compared with group A, cell proliferation was significantly increased in group B (P <0.05) and decreased in group C which had lower cell proliferation than group D (P <0.05). However, opposite results were obtained regarding cell apoptosis in four groups (P <0.05); group B showed higher INS level (145.36±8.55 pg/ml) and group C had lower level (80.14±5.36 pg/ml) than group A (105.23±7.78 pg/ml) (P <0.05). Meanwhile, AMPK and p-AMPK levels were significantly lower in group B and higher in group C than group A (P <0.05) with lower level in group D than group C (P <0.05). Whereas, opposite expression profile of p-mTOR and mTOR was found in these groups (P <0.05). High glucose inhibits INS-1 cell proliferation and promotes apoptosis. GLP-1 analogue inhibits INS-1 cell apoptosis in high glucose and accelerate proliferation possibly via regulation of AMPK/mTOR signaling pathway.


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