Experimental and Therapeutic Medicine
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2021
·Vol. 21
·期 6
·1-11
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IF 2.447
Xiaoming Lin,Guangfei Wang,Ping Liu,Lei Han,Tong Wang,Kaili Chen,Yonglin Gao
The aim of the present study was to investigate the effects of gallic acid (GA) on the proliferation and apoptosis of colon cancer cells and to further clarify the mechanism of GA function associated with SRC and EGFR phosphorylation. HCT116 and HT29 cells were treated with different concentrations of GA for 24 h. Cell proliferation and apoptosis were analyzed using plate clone formation and flow cytometry assays, respectively. In addition, the expression of apoptosis‑related proteins was examined by western blotting. Furthermore, the level of STAT3, AKT, SRC and EGFR phosphorylation was analyzed by western blotting and immunofluorescence. Subsequently, the SRC inhibitor PP2 and the EGFR inhibitor gefitinib were used to analyze the GA‑associated mechanisms. In addition, a xenograft tumor model was established to confirm the effects of GA in vivo. The results indicated that GA inhibited cell proliferation and promoted cell apoptosis by upregulating the ratio of cleaved caspase‑3/pro‑caspase‑3 and cleaved caspase‑9/pro‑caspase‑9. Concurrently, GA decreased the level of phosphorylated (p)‑SRC, p‑EGFR, p‑AKT and p‑STAT3. Following treatment with PP2 and gefitinib in both cancer cell lines and animal model, GA was demonstrated to inhibit EGFR and SRC phosphorylation to downregulate STAT3 and AKT phosphorylation. In vivo, GA prevented tumor growth, promoted tumor apoptosis and decreased the level of p‑SRC, p‑EGFR, p‑STAT3 and p‑AKT. In conclusion, GA was indicated to suppress colon cancer proliferation by inhibiting SRC and EGFR phosphorylation.
研究领域:
肿瘤学
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分子生物学
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细胞生物学
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DOI
PubMed
高影响因子
Cell Communication and Signaling
·
2024
·Vol. 22
·期 1
·1-21
·
IF 8.2
Wu Chengyan,Hu Li,Liu Bing,Zeng Xingyue,Ma Haixiang,Cao Yongkai,Li Huijun,Zhang Xiaohan
Background Desensitization of G protein–coupled receptors (GPCRs) refers to the attenuation of receptor responsiveness by prolonged or intermittent exposure to agonists. The binding of β-arrestin to the cytoplasmic cavity of the phosphorylated receptor, which competes with the G protein, has been widely accepted as an extensive model for explaining GPCRs desensitization. However, studies on various GPCRs, including dopamine D 2 -like receptors (D 2 R, D 3 R, D 4 R), have suggested the existence of other desensitization mechanisms. The present study employed D 2 R/D 3 R variants with different desensitization properties and utilized loss-of-function approaches to uncover the mechanisms underlying GPCRs homologous desensitization, focusing on the signaling cascade that regulates the ubiquitination of AKT. Results AKT undergoes K8/14 ubiquitination by TRAF6, which occurs in the nucleus and promotes its membrane recruitment, phosphorylation and activation under receptor desensitization conditions. The nuclear entry of TRAF6 relies on the presence of the importin complex. Src regulates the nuclear entry of TRAF6 by mediating the interaction between TRAF6 and importin β1. Ubiquitinated AKT translocates to the plasma membrane where it associates with Mdm2 to phosphorylate it at the S166 and S186 residues. Thereafter, phosphorylated Mdm2 is recruited to the nucleus, resulting in the deubiquitination of β-Arr2. The deubiquitinated β-Arr2 then forms a complex with Gβγ, which serves as a biomarker for GPCRs desensitization. Like in D 3 R, ubiquitination of AKT is also involved in the desensitization of β 2 adrenoceptors. Conclusion Our study proposed that the property of a receptor that causes a change in the subcellular localization of TRAF6 from the cytoplasm to the nucleus to mediate AKT ubiquitination could initiate the desensitization of GPCRs.
研究领域:
细胞生物学
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分子生物学
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药理学
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信号转导
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DOI
PubMed
高影响因子
ACS Omega
·
2017
·
IF 0
Yijun Li,Xinyu Wen,Min Nie,Qi Wang
Dendritic β-nucleating agent (β-NA) can readily manipulate the formation of dendritic β-crystal with a unique toughening effect on polypropylene (PP) to drastically enhance the ductility. However, by the current method, the geometric size is too large to fully perform the nucleating efficiency. In this study, by comparatively investigating the effect of molecular weight of PP and diffusion of β-NAs in a PP melt, we proposed a novel carrier strategy that selective enrichment of β-NAs in a PP carrier was followed by directed migration into polymer matrix. Accordingly, the growth of NAs was controlled by the release from the PP carrier, which decreased the available amount of β-NAs during the growth stage. In this case, the viscosity difference between PP carrier and matrix determined the interfacial movement of β-NAs. When the PP carrier and matrix had same molecular weight, the diffusion and release became favorable to facilitate the formation of the dense and fine dendritic aggregates. As a result, the relative content of β-crystals reached 92%, with a drastic increase of ∼82% in the optimal condition compared to the directed compounded PP/β-NAs sample. This study can open a new avenue to tailor the topologies of β-NAs and the ensuing β-crystals for high-performance PP products.
研究领域:
材料科学
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高分子化学
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DOI
PubMed
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2023
·Vol. 24
·期 12
·10031
·
IF 5.6
Haiping Liu,Haixiang Ma,Xingyue Zeng,Chengyan Wu,Srijan Acharya,Sarabjeet Kour Sudan,Xiaohan Zhang
A class-A GPCR dopamine D2 receptor (D2R) plays a critical role in the proper functioning of neuronal circuits through the downstream activation of both G-protein- and β-arrestin-dependent signaling pathways. Understanding the signaling pathways downstream of D2R is critical for developing effective therapies with which to treat dopamine (DA)-related disorders such as Parkinson’s disease and schizophrenia. Extensive studies have focused on the regulation of D2R-mediated extracellular-signal-regulated kinase (ERK) 1/2 signaling; however, the manner in which ERKs are activated upon the stimulation of a specific signaling pathway of D2R remains unclear. The present study conducted a variety of experimental techniques, including loss-of-function experiments, site-directed mutagenesis, and the determination of protein interactions, in order to investigate the mechanisms underlying β-arrestin-biased signaling-pathway-mediated ERK activation. We found that the stimulation of the D2R β-arrestin signaling pathway caused Mdm2, an E3 ubiquitin ligase, to move from the nucleus to the cytoplasm and interact with tyrosine phosphorylated G-protein-coupled receptor kinase 2 (GRK2), which was facilitated by Src, a non-receptor tyrosine kinase. This interaction led to the ubiquitination of GRK2, which then moved to the plasma membrane and interacted with activated D2R, followed by the phosphorylation of D2R as well as the mediation of ERK activation. In conclusion, Mdm2-mediated GRK2 ubiquitination, which is selectively triggered by the stimulation of the D2R β-arrestin signaling pathway, is necessary for GRK2 membrane translocation and its interaction with D2R, which in turn mediates downstream ERK signaling. This study is primarily novel and provides essential information with which to better understand the detailed mechanisms of D2R-dependent signaling.Keywords:GRK2 ubiquitination;D2R-biased signaling;Src;ERK signaling
研究领域:
神经科学
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药理学
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细胞信号
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）