scholarly journals Da Cheng Qi Decoction Alleviates Cerulein-Stimulated AR42J Pancreatic Acinar Cell Injury via the JAK2/STAT3 Signaling Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zehua Zhou ◽  
Ying Chen ◽  
Wenmin Dong ◽  
Rui An ◽  
Kun Liang ◽  
...  
Keyword(s):  
Protein Expression ◽  
Signaling Pathway ◽  
Acinar Cell ◽  
Biochemical Markers ◽  
Cell Injury ◽  
Pancreatic Acinar Cell ◽  
Stat3 Pathway ◽  
Jak2 Inhibitor ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway

Background. Acute pancreatitis (AP) is a common acute abdomen inflammation, characterized by the dysregulation of digestive enzyme production and secretion. Many studies have shown that Da Cheng Qi Decoction (DCQD) is a secure, effective prescription on AP. In this study, cerulein-stimulated AR42J cells damage model was established to further explore the feasibility and underlying mechanism of DCQD as a potential inhibitor of JAK2/STAT3 pathway for the treatment of AP. Methods. Cell viability of DCQD was measured using a cell counting Kit-8 assay. Pancreatic biochemical markers such as amylase, lipase, and C-reactive protein production were measured by assay kits, respectively. Cytokines (TNF-α, IL-6, IL-10, and IL-1β) were assayed by ELISA. Protein location and protein expression were detected by immunofluorescence staining and Western blotting, respectively. Gene expression was assessed by real-time PCR. For mechanistic analysis of the effect of DCQD on JAK2/STAT3 signaling pathway, selective JAK2 inhibitor (Fedratinib) and STAT3 inhibitor (Stattic) as well as STAT3 activator (Garcinone D) were used. Results. DCQD protected cells by regulating cerulein-induced inflammation and reducing the secretion of pancreatic biochemical markers. Moreover, DCQD could not only inhibit the nuclear translocation of p-STAT3, but also decrease the mRNA expression of JAK2 and STAT3 as well as the ratio of p-JAK2/JAK2 and p-STAT3/STAT3 in protein level. Additionally, DCQD could regulate the mRNA and protein expression of JAK2/STAT3 downstream effectors, Bax and Bcl-XL. The activated effect of cerulein on JAK2/STAT3 pathway was also reversed by JAK2 inhibitor Fedratinib or STAT3 inhibitor Stattic. And the overexpression of JAK2/STAT3 pathway, via STAT3 activator Garcinone D, did exert damage on cells, which bore a resemblance to cerulein. Conclusion. The activation of JAK2/STAT3 pathway may play a key role in the pathogenesis of cerulein-stimulated AR42J pancreatic acinar cell injury. DCQD could improve inflammatory cytokines and cell injury, which might be mediated by suppressing the activation of JAK2/STAT3 signaling pathway.

scholarly journals Da Cheng Qi Decoction Alleviates Cerulein-Stimulated AR42J Pancreatic Acinar Cell Injury via the JAK2/STAT3 Signalling Pathway

2020 ◽  
Author(s):  
Zehua Zhou ◽  
Ying Chen ◽  
Wenmin Dong ◽  
Rui An ◽  
Kun Liang ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Acinar Cell ◽  
Biochemical Markers ◽  
Cell Injury ◽  
Pancreatic Acinar Cell ◽  
Cell Counting ◽  
Stat3 Pathway ◽  
Jak2 Inhibitor ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway

Abstract Background: Acute pancreatitis (AP) is a common acute abdomen, characterized by the dysregulation of digestive enzyme production and secretion. Many studies have shown that Da Cheng Qi Decoction (DCQD) is a secure, effective prescription on AP. In this study, cerulein-stimulated AR42J cells damage model was established to further explore the feasibility and underlying mechanism of DCQD as a potential JAK2/STAT3 pathway inhibitor for the treatment of AP. Methods: Cell viability of DCQD was measured using a Cell Counting Kit-8 assay. Pancreatic biochemical markers such as amylase, lipase and C-reactive protein production were measured by assay kits respectively. Cytokines (TNF-α, IL-6, IL-10 and IL-1β) were assayed by ELISA. Protein location was detected by immunofluorescence staining. Proteins expression was quantified by Western blotting, and gene expression was assessed by real‑time PCR. For mechanistic analysis of the effect of DCQD on JAK2/STAT3 signaling pathway, selective JAK2 inhibitor (Fedratinib) and STAT3 inhibitor (Stattic) as well as STAT3 activator (Garcinone D) were used.Results: DCQD protected cells by regulating cerulein-induced inflammation and reducing the secretion of pancreatic biochemical markers. The mechanisms mediating these effects may be related to the suppression of the JAK2/STAT3 pathway. Additionally, DCQD significantly attenuated cell injury and regulated the expression of downstream targets Bax and Bcl-XL. Moreover, treatment with JAK2 inhibitor Fedratinib or STAT3 inhibitor Stattic reversed the activated effect of cerulein on JAK2/STAT3 pathway. And the activation of JAK2/STAT3 pathway, via STAT3 activator Garcinone D, did exert damage on cells, which bore a resemblance to cerulein.Conclusion: The activation of JAK2/STAT3 pathway may play a key role in the pathogenesis of cerulein-stimulated AR42J pancreatic acinar cell injury. DCQD could improve inflammatory cytokines and cell injury, which might be mediated by suppressing the activation of JAK2/STAT3 signaling pathway.

scholarly journals Inhibition of the SOCS1-JAK2-STAT3 Signaling Pathway Confers Neuroprotection in Rats with Ischemic Stroke

2017 ◽  
Vol 44 (1) ◽  
pp. 85-98 ◽  
Author(s):  
Xiao-Lei Wang ◽  
Chun-Mei Qiao ◽  
Jiong-Ou Liu ◽  
Chun-Yang Li
Keyword(s):  
Ischemic Stroke ◽  
Protein Expression ◽  
Cell Viability ◽  
Signaling Pathway ◽  
Rat Model ◽  
Caspase 3 ◽  
Neuronal Cells ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway ◽  
Mrna And Protein Expression

Background: The present study aims to investigate the protective effects of the SOCS1-JAK2-STAT3 signaling pathway on neurons in a rat model of ischemic stroke. Methods: Our study was conducted using an ischemic stroke rat model. After the microglia were extracted, 40 neonatal Sprague-Dawley (SD) rats were assigned into the blank, AG490, model and negative control (NC) groups. The neurological function of all the rats was evaluated. Histopathological changes were observed. qRT-PCR and western blotting were applied to measure the expression of genes and proteins in the SOCS1-JAK2-STAT3 signaling pathway and related to apoptosis. The TUNEL assay was conducted to calculate the cellular morphology and apoptosis of neuronal cells. Cell viability was detected using the MTT assay. In addition, immunoassays were used to measure the content of superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA) as well as the levels of oxidative stress. Results: Compared with the blank group, the model and NC groups showed higher neurological function scores—the cytoplasm of the neurons were cavitated, the organelles were reduced with unclear margins, some of the neurons were necrotic, and apoptosis was increased. In addition, the NC and model groups exhibited decreased cell viability, lower mRNA and protein expression of SOCS1 SOCS3 and bcl-2 and reduced SOD and GSH levels but higher mRNA and protein expression levels of AK2, STAT3,Bax and caspase-3 as well as increased protein expression of P-JAK2, P-STAT3 and activated caspase-3 (c-caspase-3). Moreover, the MDA levels were up-regulated in the NC and model groups. In contrast, opposing trends were found in the AG490 group compared with the NC and model groups. Conclusion: These data demonstrate that inhibiting the SOCS1-JAK2-STAT3 signaling pathway can reduce the loss of nerve function and apoptosis of neuronal cells, which provides a new target for the clinical treatment of ischemic stroke.

Acute Monocytic Leukemia Associated Antigen MLAA-34 up-Regulates JAK2/STAT3 Expression and JAK2/STAT3 Enhances MLAA-34 Activation in a Positive Feedback Loop

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1393-1393
Author(s):  
Bo Lei ◽  
Ju Bai ◽  
Wanggang Zhang ◽  
Aili He ◽  
Yinxia Chen ◽  
...  
Keyword(s):  
Western Blot ◽  
Signaling Pathway ◽  
Expression Vectors ◽  
Acute Monocytic Leukemia ◽  
U937 Cells ◽  
Rt Pcr ◽  
Monocytic Leukemia ◽  
Stat3 Pathway ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway

Abstract Backgroud: The MLAA-34 gene (GenBank no. AY288977.2) was first discovered in acute monocytic leukemia (M5) in an effort to identify monocytic leukemia-associated antigens by serologic analysis of a recombinant cDNA expression library (SEREX). Previous study showed that high MLAA-34 levels were independently associated with a poorer relapse-free survival and overall survival in AML patients. The MLAA-34 is located on 13q14.2 and has been confirmed to be a novel splice variant of CAB39L (calcium binding protein 39-like). Both mRNA and protein levels of MLAA-34 were found to be higher in U937 cells and M5 patients. The study confirmed that MLAA-34 plays a role in the antiapoptosis of U937 cells, and has the function of oncogenes. Objective: This study is to explore the relationship of MLAA-34 and JAK2/STAT3 signaling pathway so as to further clarify antiapoptotic mechanisms of MLAA-34. Method: Potential binding sites for STAT3 was identified by computer-assisted analysis of the core promoter of MLAA-34 gene. We analyzed the role of STAT3 in the regulation of MLAA-34 gene expression in U937 cells by site-specific mutation, chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assay (EMSA). The expression of MLAA-34 was detected by RT-PCR and western blot after over-expressing and interfering STAT3. Through the different concentrations of AG490 (JAK2 inhibitors) and different concentrations of IL- 6 (JAK2 activator) study JAK2/STAT3 signaling pathway upregulated MLAA-34 expression. The gene chip and co-IP were applied to study the MLAA-34-induced JAK2/STAT3 activation. Peripheral blood mononuclear cells and bone marrow (BM) cells of M5 patients were obtained. In M5 patients, mRNA and protein expression of JAK-2, STAT3, p-STAT3 and MLAA-34 were determined by quantitative RT-PCR and western blot respectively to verify the forward feedback regulation pathway. Result: The reporter assay showed that the activity of reporter gene was downregulated after the mutation of STAT3 binding sites. ChIP assay and EMSA showed that STAT3 can directly bind to MLAA-34 gene promoter. The expression vectors of MLAA-34 as well as siRNA eukaryotic expression vectors respectively targeting STAT3 were successfully constructed. RT-PCR and western blot results showed that STAT3 can increase the level of MLAA-34. Research of administration of different concentrations of AG490 and different concentrations of IL-6 showed that JAK2/STAT3 signaling pathway could upregulate MLAA-34 expression. AML-M5 NOD / SCID mice leukemia model was successfully constructed,.Konckdown of MLAA-34 gene can promote apoptosis of leukemia cells, inhibit tumor growth and prolong survival time. Total RNA from shRNA-MLAA-34/U937 and Vec/U937 cells were analyzed by Human Genome U133 chip. Heat-map showed reduced expression of JAK2/STAT3 pathway genes. The result was verified by qPCR and western blot. CO-IP showed that MLAA-34 could form a complex with endogenous JAK2 under the enhanced role of IL-6. Thereby activating JAK2 may directly or indirectly dependent on the presence of MLAA-34. Furthermore, we detected JAK-2, STAT3, P-STAT3 and MLAA-34 gene and protein level in M5 patients, the results showed that they have a positive correlation. Conclusion: JAK2/STAT3 pathway up-regulates MLAA-34 transcription, and MLAA-34 enhances JAK2/STAT3 pathway activation. The forward feedback regulation may have profound therapeutic implications for M5 and could help invent novel approaches in treatment for acute monocytic leukemia. Disclosures No relevant conflicts of interest to declare.

scholarly journals Da-Cheng-Qi Decoction Alleviates Intestinal Injury in Rats with Severe Acute Pancreatitis by Inhibiting the JAK2-STAT3 Signaling Pathway

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Wenyin Jin ◽  
Yinfeng Shen
Keyword(s):  
Acute Pancreatitis ◽  
Signaling Pathway ◽  
Inflammatory Cytokines ◽  
Severe Acute Pancreatitis ◽  
Terminal Ileum ◽  
Intestinal Injury ◽  
Janus Kinase ◽  
Jak2 Inhibitor ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway

Objective. To investigate the effect of Da-Cheng-Qi decoction (DCQD) on treating intestinal injury in rats with severe acute pancreatitis (SAP), based on the Janus kinase 2 (JAK2)/signal transducers and transcription 3 (STAT3) signaling pathway. Methods. Rats were randomly divided into the SAP group, SAP + ruxolitinib (JAK2 inhibitor) group, SAP + Stattic (STAT3 inhibitor) group, SAP + DCQD group, and sham operation group. They were further divided into 3-hour, 6-hour, 12-hour, and 18-hour subgroups. Levels of amylase and the inflammatory cytokines tumor necrosis factor-α, interleukin 6, interleukin 10, and interleukin 4 in plasma were tested. The messenger ribonucleic acid (mRNA) expression of JAK2 and STAT3 and the protein expression of phosphorylated JAK2 (p-JAK2) and phosphorylated STAT3 (p-STAT3) in the pancreas and terminal ileum tissues were examined. Results. Rats with SAP had severe changes in plasma levels of amylase and inflammatory cytokines and showed an overexpression of JAK2 mRNA, STAT3 mRNA, p-JAK2 protein, and p-STAT3 protein in the pancreas and terminal ileum. The events could be downregulated by treatment with DCQD, JAK2 inhibitor, and STAT3 inhibitor. Conclusions. In rats with SAP, DCQD ameliorated inflammatory cytokines and intestinal injury, which may be closely associated with the inhibition of the JAK2/STAT3 signaling pathway.

scholarly journals JAK2/STAT3 Pathway Mediates Protection of Metallothionein Against Doxorubicin-Induced Cytotoxicity in Mouse Cardiomyocytes

2015 ◽  
Vol 35 (3) ◽  
pp. 317-326 ◽  
Author(s):  
Jing Rong ◽  
Lizhong Li ◽  
Li Jing ◽  
Haiqin Fang ◽  
Shuangqing Peng
Keyword(s):  
Protein Expression ◽  
Anticancer Agents ◽  
Messenger Rna ◽  
Protein Tyrosine Kinase ◽  
Kinase Inhibitor ◽  
Reactive Oxygen Species Generation ◽  
Stat3 Pathway ◽  
Jak2 Inhibitor ◽  
Stat3 Signaling Pathway

Doxorubicin (Dox) is one of the most important anticancer agents; however, its clinical application is limited by its severe cardiotoxicity. In our previous study, we found that the gene expression levels of the Janus-activated kinase/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway were different between MT−/− cardiomyocytes and MT+/+ cardiomyocytes when they were treated with Dox. Thus, this study was intended to investigate the role of JAK2/STAT3 pathway in metallothionein (MT) protection of Dox-induced cardiotoxicity. Tyrphostin AG490 (α-cyano-(3,4-dihydroxy)-N-benzylcinnamide) is a synthetic protein tyrosine kinase inhibitor which at first has been considered as a specific JAK2 inhibitor and can inhibit the JAK2/STAT3 signaling pathway. In the present study, AG490 was used to assess the role of JAK2/STAT3 in MT protection against Dox-induced cardiotoxicity. The AG490 can attenuate the MT protection by increasing lactate dehydrogenase and the number of apoptotic cells. Interestingly, pretreated with AG490, MT−/− cardiomyocytes were more sensitive than MT+/+ to Dox-induced cytotoxicity as measured by reactive oxygen species generation, lipid peroxidation, and protein carbonylation. Metallothionein 1 and MT-2 messenger RNA were upregulated by Dox, and AG490 decreased the protein expression of MT-1 and MT-2. After Dox treatment, the protein expression of p-Jak2 and p-Stat3 levels was significantly increased in MT+/+ cardiomyocytes, suggesting that the JAK2/STAT3 pathway was partially involved in MT protection against Dox-induced cardiotoxicity.

scholarly journals Renoprotective Effect of the Recombinant Anti-IL-6R Fusion Proteins by Inhibiting JAK2/STAT3 Signaling Pathway in Diabetic Nephropathy

2021 ◽  
Vol 12 ◽  
Author(s):  
Nanwen Zhang ◽  
Qingmei Zheng ◽  
Yaduan Wang ◽  
Juan Lin ◽  
He Wang ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Signaling Pathway ◽  
Interleukin 6 ◽  
Fusion Proteins ◽  
Mesangial Cells ◽  
Glomerular Mesangial Cells ◽  
Stat3 Pathway ◽  
Renoprotective Effect ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway

Diabetic nephropathy the main reason for end stage renal disease is a common microvascular complication in patients with type 1 and type 2 diabetes. The interleukin-6 (IL-6), acting as a pleiotropic cytokine, play key roles in main autoimmune disorders. The recombinant anti-IL-6R fusion proteins (VHH-0031) constructed and obtained in our lab is a dual target-directed single domain-based fusion protein against the interleukin-6 receptor. This study aims to explore the renoprotective effect of VHH-0031 in diabetic nephropathy. VHH-0031 treatment alleviated renal inflammation, morphologic injury and renal insufficiency in both Goto-Kakizaki rats and STZ-induced Sprague Dawley rats. These renoprotective effects of VHH-0031 are associated with alleviating inflammation and suppression of the JAK2/STAT3 signaling pathway. The mesangial cells treated with VHH-0031 exhibited anti-proliferation, anti-inflammation and inactivation of JAK2/STAT3 pathway under high glucose condition. In conclusion, this study demonstrates that VHH-0031 exhibited a potent protective effect in kidney of diabetic rats and its mechanism may be concerned with the inhibition of the IL-6R/JAK2/STAT3 pathway of glomerular mesangial cells.

scholarly journals LINC00893 Inhibits The Progression of Prostate Cancer Through miR-3173-5p/SOCS3/JAK2/STAT3 Pathway

2021 ◽  
Author(s):  
Chuigong Yu ◽  
Yu Fan ◽  
Yu Zhang ◽  
Lupeng Liu ◽  
Gang Guo
Keyword(s):  
Prostate Cancer ◽  
Signaling Pathway ◽  
Cell Lines ◽  
Janus Kinase ◽  
Luciferase Reporter ◽  
Mesenchymal Transition ◽  
Stat3 Pathway ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway

Abstract Background: Prostate cancer (PCa) is one of the most common malignant tumors in the male urinary system. In recent years, the morbidity and mortality of PCa have been increasing due to the limited effects of existing treatment strategies. Long non-coding RNA (lncRNA) LINC00893 inhibits the proliferation and metastasis of papillary thyroid cancer (PTC) cells, but its role in PCa has not been reported. Our study aims to clarify the role and underlying mechanism of LINC00893 in regulating the progression of PCa.Methods: We analyzed LINC00893 expression through TCGA database. We also collected 66 paires of PCa tissues and matched para-cancerous tissues as well as cell lines and assessed LINC00893 expression. Subsequently, we conducted gain-of-function assays to confirm the role of LINC00893 in PCa. CCK-8, EdU, colony information and transwell assays were implemented to detect cell proliferation, colony formation and metastasis abilities, respectively. RT-qPCR and western blot assays were used to quantify the expression of mRNA and protein. Dual-luciferase reporter, RNA-binding protein immunoprecipitation (RIP) and RNA pull down assays were conducted to evaluate the interaction of molecules. Spearman correlation coefficient analysis was conducted to detect the correlation between molecules.Results: We found that the LINC00893 expression in PCa tissues and cell lines was upregulated compared with matched controls, and patients with low expression of LINC00893 suffered a low overall survival rate. Overexpression of LINC00893 hindered the proliferation, epithelial-mesenchymal transition (EMT) as well as metastasis of PCa cells in vitro and in vivo. In terms of mechanism, suppressor of cytokine signaling 3 (SOCS3)/Janus Kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway occupied a central position in the regulation of PCa progression by LINC00893. LINC00893 weakened the inhibition role of miR-3173-5p on SOCS3 expression through functioning as a miR-3173-5p sponge, which inhibited the JAK2/STAT3 signaling pathway. Conclusions: LINC00893 suppresses the progression of prostate cancer through miR-3173-5p/SOCS3/JAK2/STAT3 pathway. our data uncovers a novel mechanism by which LINC00893 hinders the progression of PCa, which enriches the molecular network of LINC00893 regulating the PCa progression and laies a theoretical foundation for PCa targeted therapy.

Polycyclic polyprenylated acylphloroglucinols from Garcinia xanthochymus fruits exhibit antitumor effects through inhibition of the STAT3 signaling pathway

2020 ◽  
Vol 11 (12) ◽  
pp. 10568-10579
Author(s):  
Jing Xu ◽  
Shan Jin ◽  
Fei Gan ◽  
Hui Xiong ◽  
Zhinan Mei ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Antitumor Effects ◽  
Stat3 Pathway ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway ◽  
Garcinia Xanthochymus

PPAPs from Garcinia xanthochymus fruits exhibit antitumor effects through STAT3 pathway.

scholarly journals MicroRNA-21 Regulates the Proliferation, Differentiation, and Apoptosis of Human Renal Cell Carcinoma Cells by the mTOR-STAT3 Signaling Pathway

2016 ◽  
Vol 24 (5) ◽  
pp. 371-380 ◽  
Author(s):  
Tao Liang ◽  
Xiao-Yong Hu ◽  
Yong-Hui Li ◽  
Bin-Qiang Tian ◽  
Zuo-Wei Li ◽  
...  
Keyword(s):  
Renal Cell Carcinoma ◽  
Protein Expression ◽  
Cell Carcinoma ◽  
Mrna Expression ◽  
Signaling Pathway ◽  
Renal Cell ◽  
Caspase 3 ◽  
Human Renal Cell Carcinoma ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway

MicroRNA-21 (miRNA-21), a kind of short, noncoding RNAs, functioned as a tumor marker and was upregulated in renal cell carcinoma (RCC). However, the underlying mechanisms of miRNA-21 in RCC were uncertain. Therefore, the effects and mechanisms of miRNA-21 on the proliferation, differentiation, and apoptosis of cultured human RCC cells were further investigated in this study. After slicing miRNA-21 in RCC cells, the viability, mRNA expression of C/EBPα and PPARγ, caspase 3 activity, and protein expression of mTOR, STAT3, and pSTAT3 were determined. It was found that knockdown of miRNA-21 downregulated the optical density (OD) value of cells, inhibited mRNA expression of PPARγ and C/EBPα, and enhanced activity of caspase 3. Furthermore, protein expression of pSTAT3 was also decreased in the absence of miRNA-21. Notably, miRNA-21-changed proliferation, differentiation, and apoptosis of human RCC cells were partially regulated following the block of the mTOR-STAT3 signaling pathway by the mTOR inhibitor (XL388). It was indicated that miRNA-21 promoted proliferation and differentiation and decreased apoptosis of human RCC cells through the activation of the mTOR-STAT3 signaling pathway.

scholarly journals The PAK1-Stat3 Signaling Pathway Activates IL-6 Gene Transcription and Human Breast Cancer Stem Cell Formation

Cancers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1527 ◽  
Author(s):  
Ji-Hyang Kim ◽  
Hack Sun Choi ◽  
Su-Lim Kim ◽  
Dong-Sun Lee
Keyword(s):  
Breast Cancer ◽  
Signaling Pathway ◽  
Cell Formation ◽  
Janus Kinase ◽  
Mobility Shift ◽  
Mammosphere Formation ◽  
Jak2 Inhibitor ◽  
Stat3 Signaling ◽  
Group I ◽  
Stat3 Signaling Pathway

Cancer stem cells (CSCs) have unique properties, including self-renewal, differentiation, and chemoresistance. In this study, we found that p21-activated kinase (PAK1) inhibitor (Group I, PAK inhibitor, IPA-3) and inactivator (ivermectin) treatments inhibit cell proliferation and that tumor growth of PAK1-knockout cells in a mouse model is significantly reduced. IPA-3 and ivermectin inhibit CSC formation. PAK1 physically interacts with Janus Kinase 2 (JAK2), and JAK2 inhibitor (TG101209) treatment inhibits mammosphere formation and reduces the nuclear PAK1 protein level. PAK1 interacts with signal transducer and activator of transcription 3 (Stat3), and PAK1 and Stat3 colocalize in the nucleus. We show through electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (ChIP), and reporter assays that the PAK1/Stat3 complex binds to the IL-6 promoter and regulates the transcription of the IL-6 gene. Inhibition of PAK1 and JAK2 in mammospheres reduces the nuclear pStat3 and extracellular IL-6 levels. PAK1 inactivation inhibits CSC formation by decreasing pStat3 and extracellular IL-6 levels. Our results reveal that JAK2/PAK1 dysregulation inhibits the Stat3 signaling pathway and CSC formation, the PAK1/Stat3 complex regulates IL-6 gene expression, PAK1/Stat3 signaling regulates CSC formation, and PAK1 may be an important target for treating breast cancer.

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