scholarly journals Periodic Mechanical Stress Activates PKCδ-Dependent EGFR Mitogenic Signals in Rat Chondrocytes via PI3K-Akt and ERK1/2

2016 ◽  
Vol 39 (4) ◽  
pp. 1281-1294 ◽  
Author(s):  
Peng He ◽  
Nan Shen ◽  
Gongming Gao ◽  
Xuefeng Jiang ◽  
Huiqing Sun ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Phosphorylation Site ◽  
Growth Factor Receptor ◽  
Cell Counting ◽  
Chondrocyte Proliferation ◽  
Extracellular Signal ◽  
Investigation Methods ◽  
Direct Cell ◽  
Sense And Respond ◽  
Static Conditions

Background/Aims: The present study aimed to analyze the mechanisms by which periodic mechanical stress is translated into biochemical signals, and to verify the important role of signaling molecules including phosphatidylinositol-3-kinase (PI3K)-Akt, protein kinase C (PKC), and epidermal growth factor receptor (EGFR) in chondrocyte proliferation. The effects of periodic mechanical stress on the mitogenesis of chondrocytes have been studied extensively in recent years. However, the mechanisms underlying the ability of chondrocytes to sense and respond to periodic mechanical stress need further investigation. Methods: Two steps were undertaken in the experiment. In the first step, the cells were pretreated with shRNA targeted to Akt or EGFR or PKCδ or control scrambled shRNA. Moreover, they were pretreated with LY294002, GF109203X, Gö6976, rottlerin, and AG1478. They were maintained under static conditions or periodic mechanical stress for 3 days, 8 h per day, prior to direct cell counting and CCK-8 assay, respectively. In the second step, the cells were pretreated with shRNA targeted to Akt or EGFR or PKCδ or control scrambled shRNA. Moreover, they were pretreated with LY294002, AG1478, and rottlerin. They were maintained under static conditions or periodic mechanical stress for 1 h prior to Western blot analysis. Results: Proliferation was inhibited by pretreatment with PKC or PKCδ inhibitor GF109203X or rottlerin and by short hairpin RNA (shRNA) targeted to PKCδ, but not by PKCα inhibitor Gö6976 in chondrocytes in response to periodic mechanical stress. Meantime, rottlerin and shRNA targeted to PKCδ also attenuated EGFR, Akt, and ERK1/2 activation. Furthermore, inhibiting EGFR activity by AG1478 and shRNA targeted to EGFR abrogated chondrocyte proliferation and phosphorylation levels of Akt and extracellular signal-regulated kinase (ERK)1/2 subjected to periodic mechanical stress, while the phosphorylation site of PKCδ was not affected. In addition, pretreatment with the PI3K-Akt-selective inhibitor LY294002 and shRNA targeted to Akt reduced periodic mechanical stress-induced chondrocyte proliferation and phosphorylation of ERK1/2, while the phosphorylation levels of EGFR and PKCδ were not inhibited. Conclusion: These findings suggested that periodic mechanical stress promoted chondrocyte proliferation through PKCδ-EGFR-PI3K-Akt-ERK1/2. They provide a stronger viewpoint for further investigations into chondrocyte mechanobiology under periodic mechanical stress and the ways to improve the quality of tissue-engineered cartilage.

scholarly journals Periodic Mechanical Stress Stimulates Cav-1-Dependent IGF-1R Mitogenic Signals in Rat Chondrocytes Through ERK1/2

2018 ◽  
Vol 48 (4) ◽  
pp. 1652-1663 ◽  
Author(s):  
Kewei Ren ◽  
Jilei Tang ◽  
Xuefeng Jiang ◽  
Huiqing Sun ◽  
Luming Nong ◽  
...  
Keyword(s):  
Western Blot ◽  
Mechanical Stress ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Biological Effects ◽  
Phosphorylation Site ◽  
Cell Counting ◽  
Mechanical Stimuli ◽  
Chondrocyte Proliferation ◽  
Static Conditions

Background/Aims: The biological effects of periodic mechanical stress on the mitogenesis of chondrocytes have been studied extensively over the past few years. However, the mechanisms underlying the ability of chondrocytes to sense and respond to mechanical stimuli remain to be determined. In the current study, we analyzed the mechanisms by which periodic mechanical stress is translated into biochemical signals and verified the key role of non-integrin mechanosensors including Caveolin-1 (Cav-1), and insulin-like growth factor-1 receptor (IGF-1R) in chondrocyte proliferation. Methods: Two steps were undertaken in the experiment. In the first step, the cells were maintained under static conditions or periodic mechanical stress for 0 h and 1 h prior to Western blot analysis. In the second step, the cells were pretreated with short hairpin RNA (shRNA) targeted to Cav-1 or IGF-1R or control scrambled shRNA. Moreover, they were pretreated with their selective inhibitors methyl β-cyclodextrin (MCD) or Linsitinib (OSI-906). They were maintained under static conditions or periodic mechanical stress for 1 h prior to Western blot analysis, and for 3 days, 8 h per day, prior to direct cell counting and CCK-8 assay, respectively. Results: Periodic mechanical stress significantly induced sustained phosphorylation of Cav-1 at Tyr14 and IGF-1R at Tyr1135/1136. Proliferation was inhibited by pretreatment with Cav-1 inhibitor MCD and by shRNA targeted to Cav-1 in chondrocytes in response to periodic mechanical stress. Meantime, MCD and shRNA targeted to Cav-1 also attenuated IGF-1R, and extracellular signal-regulated kinase (ERK)1/2 activation. In addition, inhibiting IGF-1R activity by Linsitinib and shRNA targeted to IGF-1R abrogated chondrocyte proliferation and phosphorylation level of ERK1/2 subjected to periodic mechanical stress, while the phosphorylation site of Cav-1 was not affected. Conclusion: These findings collectively suggested that periodic mechanical stress promoted chondrocyte proliferation through Cav-1-IGF-1R-ERK1/2.

scholarly journals Periodic Mechanical Stress INDUCES Chondrocyte Proliferation and Matrix Synthesis via CaMKII-Mediated Pyk2 Signaling

2017 ◽  
Vol 42 (1) ◽  
pp. 383-396 ◽  
Author(s):  
Wenwei Liang ◽  
Zeng Li ◽  
Zhen Wang ◽  
Jinchun Zhou ◽  
Huanghe Song ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Cell Counting ◽  
Synthesis Methods ◽  
Matrix Synthesis ◽  
Gene Expressions ◽  
Chondrocyte Proliferation ◽  
Direct Cell ◽  
Engineered Cartilage ◽  
Signal Activation

Background/Aims: Periodic mechanical stress can promote chondrocyte proliferation and matrix synthesis to improve the quality of tissue-engineered cartilage. Although the integrin β1–ERK1/2 signal cascade has been implicated in periodic mechanical stress-induced mitogenic effects in chondrocytes, the precise mechanisms have not been fully established. The current study was designed to probe the roles of CaMKII and Pyk2 signaling in periodic mechanical stress-mediated chondrocyte proliferation and matrix synthesis. Methods: Chondrocytes were subjected to periodic mechanical stress, proliferation was assessed by direct cell counting and CCK-8 assay; gene expressions were analyzed using quantitative real-time PCR, protein abundance by Western blotting. Results: Mechanical stress, markedly enhanced the phosphorylation levels of Pyk2 at Tyr402 and CaMKII at Thr286. Both suppression of Pyk2 with Pyk2 inhibitor PF431396 or Pyk2 shRNA and suppression of CaMKII with CaMKII inhibitor KN-93 or CaMKII shRNA blocked periodic mechanical stress-induced chondrocyte proliferation and matrix synthesis. Additionally, either pretreatment with KN-93 or shRNA targeted to CaMKII prevented the activation of ERK1/2 and Pyk2 under conditions of periodic mechanical stress. Interestingly, in relation to periodic mechanical stress, in the context of Pyk2 inhibition with PF431396 or its targeted shRNA, only the phosphorylation levels of ERK1/2 were abrogated, while CaMKII signal activation was not affected. Moreover, the phosphorylation levels of CaMKII- Thr286 and Pyk2- Tyr402 were abolished after pretreatment with blocking antibody against integrinβ1 exposed to periodic mechanical stress. Conclusion: Our results collectively indicate that periodic mechanical stress promotes chondrocyte proliferation and matrix synthesis through the integrinβ1–CaMKII–Pyk2–ERK1/2 signaling cascade.

scholarly journals Periodic Mechanical Stress Stimulates GIT1-Dependent Mitogenic Signals in Rat Chondrocytes Through ERK1/2 Activity

2018 ◽  
Vol 50 (3) ◽  
pp. 1015-1028 ◽  
Author(s):  
Kewei Ren ◽  
Jilei Tang ◽  
Xuefeng Jiang ◽  
Huiqing Sun ◽  
Luming Nong ◽  
...  
Keyword(s):  
Western Blot ◽  
Mechanical Stress ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Cell Counting ◽  
Mechanical Stimuli ◽  
Wild Type ◽  
Integrin Β1 ◽  
Chondrocyte Proliferation ◽  
Blocking Antibody

Background/Aims: The mitogenic effects of periodic mechanical stress on chondrocytes have been studied extensively, but the mechanisms whereby chondrocytes sense and respond to mechanical stimuli remain to be determined. We explored the question and verified the key role of G protein coupled receptor kinase interacting protein 1 (GIT1) signaling in periodic mechanical stress-induced chondrocyte proliferation. Methods: Two steps were undertaken in the experiment. In the first step, the cells were maintained under non-pressure conditions or periodic mechanical stress for 1 h prior to Western blot analysis. In the second step, the cells were pretreated with short hairpin RNA (shRNA) targeted to GIT1 or Src or control scrambled shRNA, or transfected with GIT1 wild-type or GIT1 mutant Y321F, or focal adhesion kinase (FAK) wild-type or FAK mutants Y397F or Y576F/Y577, respectively. Moreover, the cells were pretreated with blocking antibody against integrin β1 or PP2. Then the cells were maintained under non-pressure conditions or periodic mechanical stress for 1 h prior to Western blot analysis, and for 3 days, 8 h per day, prior to direct cell counting and CCK-8 assay, respectively. Results: Periodic mechanical stress significantly induced sustained phosphorylation of GIT1 at Tyr321. Reduction of GIT1 with shRNA targeted to GIT1 and GIT1 mutant Y321F inhibited periodic mechanical stress-promoted chondrocyte proliferation, accompanied by attenuated extracellular signal-regulated kinase (ERK)1/2 and FAK phosphorylation at Tyr576/577. However, activation of Src and FAK-Tyr397 was not prevented upon GIT1 suppression. Furthermore, pretreatment with blocking antibody against integrin β1, Src-selective inhibitor, PP2, and shRNA targeted to Src blocked GIT1 activation under periodic mechanical stress. In addition, GIT1 phosphorylation at Tyr321 was not reduced upon pretreatment with FAK mutants Y397F or Y576F/Y577 under conditions of periodic mechanical stress. Conclusion: These findings collectively suggested that periodic mechanical stress promoted chondrocyte proliferation through at least two separate pathways, integrin β1-Src-GIT1-FAK(Tyr576/577)-ERK1/2, and the other parallel GIT1-independent integrin β1-FAK(Tyr397)-ERK1/2.

scholarly journals Proteomic Analysis Reveals Grb2 as a Key Regulator of Periodic Mechanical Stress Transduction in Chondrocytes

2017 ◽  
Vol 44 (4) ◽  
pp. 1509-1525 ◽  
Author(s):  
Shun Xu ◽  
Zeng Li ◽  
Zhen Wang ◽  
Chenjun Zhai ◽  
Wenwei Liang ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Proteomic Analysis ◽  
Lentiviral Vector ◽  
Biological Effects ◽  
Growth Factor Receptor ◽  
Fold Increase ◽  
Mechanical Stimuli ◽  
Proteomic Data ◽  
Extracellular Signal ◽  
First Time

Background/Aims: Periodic mechanical stress could significantly promote chondrocyte proliferation and matrix synthesis. However, the mechanisms underlying the ability of chondrocyte detecting and responding to periodic mechanical stimuli have not been well delineated. Methods: Quantitative proteomic analysis was performed to construct the differently expressed proteome profiles of chondrocyte under pressure. Then a combination of Western blot, quantitative real-time PCR, lentiviral vector and histological methods were used to confirm the proteomic results and investigate the mechanoseing mechanism. Results: Growth factor receptor-bound protein 2 (Grb2), a component of integrin adhesome, was found a 1.49-fold increase in dynamic stress group. This process was mediated through integrin β1, leading to increased phosphorylation of focal adhesion kinase (FAK) and extracellular signal–regulated kinase 1/2 (ERK1/2) respectively and then produce the corresponding biological effects. Conclusion: This was the first time to demonstrate Grb2 has such an important role in periodic mechanotransduction, and the proteomic data could facilitate the further investigation of chondrocytes mechanosensing.

scholarly journals Role of thyroid hormone-integrin αvβ3-signal and therapeutic strategies in colorectal cancers

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Yu-Chen S. H. Yang ◽  
Po-Jui Ko ◽  
Yi-Shin Pan ◽  
Hung-Yun Lin ◽  
Jacqueline Whang-Peng ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Cancer Cell ◽  
Growth Factor Receptor ◽  
Integrin Αvβ3 ◽  
Ras Signaling ◽  
Structural Protein ◽  
Cancer Cell Growth ◽  
Ras Pathway ◽  
Extracellular Signal ◽  
Cell Progression

AbstractThyroid hormone analogues—particularly, l-thyroxine (T4) has been shown to be relevant to the functions of a variety of cancers. Integrin αvβ3 is a plasma membrane structural protein linked to signal transduction pathways that are critical to cancer cell proliferation and metastasis. Thyroid hormones, T4 and to a less extend T3 bind cell surface integrin αvβ3, to stimulate the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway to stimulate cancer cell growth. Thyroid hormone analogues also engage in crosstalk with the epidermal growth factor receptor (EGFR)-Ras pathway. EGFR signal generation and, downstream, transduction of Ras/Raf pathway signals contribute importantly to tumor cell progression. Mutated Ras oncogenes contribute to chemoresistance in colorectal carcinoma (CRC); chemoresistance may depend in part on the activity of ERK1/2 pathway. In this review, we evaluate the contribution of thyroxine interacting with integrin αvβ3 and crosstalking with EGFR/Ras signaling pathway non-genomically in CRC proliferation. Tetraiodothyroacetic acid (tetrac), the deaminated analogue of T4, and its nano-derivative, NDAT, have anticancer functions, with effectiveness against CRC and other tumors. In Ras-mutant CRC cells, tetrac derivatives may overcome chemoresistance to other drugs via actions initiated at integrin αvβ3 and involving, downstream, the EGFR-Ras signaling pathways.

Molecular Mechanism and Prediction of Sorafenib Chemoresistance in Human Hepatocellular Carcinoma

2015 ◽  
Vol 33 (6) ◽  
pp. 771-779 ◽  
Author(s):  
Naoshi Nishida ◽  
Masayuki Kitano ◽  
Toshiharu Sakurai ◽  
Masatoshi Kudo
Keyword(s):  
Hepatocellular Carcinoma ◽  
Growth Factor ◽  
Kinase Inhibitor ◽  
Epithelial Mesenchymal Transition ◽  
Growth Factor Receptor ◽  
Stem Cell Markers ◽  
Mesenchymal Transition ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Underlying Mechanisms

Hepatocellular carcinoma (HCC) is the second leading cause of cancer death worldwide, and prognosis remains unsatisfactory when the disease is diagnosed at an advanced stage. Many molecular targeted agents are being developed for the treatment of advanced HCC; however, the only promising drug to have been developed is sorafenib, which acts as a multi-kinase inhibitor. Unfortunately, a subgroup of HCC is resistant to sorafenib, and the majority of these HCC patients show disease progression even after an initial satisfactory response. To date, a number of studies have examined the underlying mechanisms involved in the response to sorafenib, and trials have been performed to overcome the acquisition of drug resistance. The anti-tumor activity of sorafenib is largely attributed to the blockade of the signals from growth factors, such as vascular endothelial growth factor receptor and platelet-derived growth factor receptor, and the downstream RAF/mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase (MEK)/ERK cascade. The activation of an escape pathway from RAF/MEK/ERK possibly results in chemoresistance. In addition, there are several features of HCCs indicating sorafenib resistance, such as epithelial-mesenchymal transition and positive stem cell markers. Here, we review the recent reports and focus on the mechanism and prediction of chemoresistance to sorafenib in HCC.

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