Activating JNK Signaling Pathway Research Articles

Tripterine Inhibits Proliferation and Promotes Apoptosis of Keloid Fibroblasts by Targeting ROS/JNK Signaling.

Keloids are benign skin tumors characterized by excessive fibroblast proliferation and collagen deposition. The current treatment of keloids with hormone drug injection, surgical excision, radiotherapy, physical compression, laser therapy, cryotherapy often have unsatisfactory outcomes. The phytochemical compounds have shown great potential in treating keloids. Tripterine, a natural triterpene derived from the traditional Chinese medicine Thunder God Vine (Tripterygium wilfordii), was previously reported to exhibit an anti-scarring bioactivity in mouse embryonic fibroblast NIH/3T3 cells. Accordingly, our study was dedicated to explore its role in regulating the pathological phenotypes of keloid fibroblasts. Human keloid fibroblasts were treated with tripterine (0-10 μM) for 24 hours. Cell viability, proliferation, migration, apoptosis, and extracellular matrix (ECM) deposition were determined by CCK-8, EdU, wound healing, Transwell, flow cytometry, western blotting, and RT-qPCR assays. The effects of tripterine treatment on reactive oxygen species (ROS) generation and JNK activation in keloid fibroblasts were assessed by DCFH-DA staining and western blotting analysis. Tripterine at the concentrations higher than 4 μM attenuated the viability of human keloid fibroblasts in a dose-dependent manner. Treatment with tripterine (4, 6, and 8 μM) dose-dependently inhibited cell proliferation and migration, promoted cell apoptosis, reduced α-SMA, Col1, and Fn expression, induced ROS production, and enhanced JNK phosphorylation in keloid fibroblasts. Collectively, tripterine ameliorates the pathological characteristics of keloid fibroblasts that are associated with keloidformation and growth by inducing ROS generation and activating JNK signalingpathway.

Rac2 enhances activation of microglia and astrocytes, inflammatory response, and apoptosis via activating JNK signaling pathway and suppressing SIRT1 expression in chronic constriction injury-induced neuropathic pain.

Neuropathic pain (NP) is pain caused by injury or dysfunction of the somatosensory system. The role of Rac2, a member of the Rac family, which is expressed in neutrophils, macrophages, and adult T cells, in NP remains unclear. Using a chronic constriction injury (CCI)-induced NP model in rats, we found that Rac2 expression was elevated in rats with CCI-induced NP and that overexpression of Rac2 aggravated the NP. Rac2 overexpression also aggravated the inflammatory response, induced activation of microglia and astrocytes, and enhanced apoptosis whereas knockdown of Rac2 had the opposite effects. Rac2 suppressed SIRT1 expression via activating the c-Jun N-terminal kinase (JNK) signaling pathway. In rescue experiments, SRT1720, an activator of SIRT1, reversed the effect of Rac2 on glial activation, inflammatory response, and apoptosis. These findings indicate that Rac2 enhances the activation of microglia and astrocytes, inflammatory response, and apoptosis via activating the JNK signaling pathway and suppressing SIRT1 expression in CCI-induced NP.

EVL Promotes Osteo-/Odontogenic Differentiation of Dental Pulp Stem Cells via Activating JNK Signaling Pathway.

Human dental pulp stem cells (hDPSCs) were recognized as a suitable and promising source of stem cells in dental pulp regeneration. However, the mechanism by which hDPSCs differentiation into osteo-/odontogenic lineage remains unclear. Ena/VASP-like protein (EVL) has been found to be involved in diverse biological processes. In this study, we explored the role and underlying mechanism of EVL in osteo-/odontogenic differentiation of hDPSCs. Expression of EVL was detected in hDPSCs by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot (WB) analyses during osteo-/odontogenic differentiation. The function of EVL in osteo-/odontogenic differentiation and involvement of MAPK signaling pathways were evaluated by alkaline phosphatase (ALP) staining and activity, alizarin red staining (ARS), and qRT-PCR and western blot analyses. The expression of EVL was upregulated during osteo-/odontogenic differentiation of hDPSCs. Overexpression of EVL significantly increased osteo-/odontogenic capacity of hDPSCs, which was reflected in increased alkaline phosphatase (ALP) staining, ALP activity, mineralized nodule formation, and the expressions of genes related to osteo-/odontogenic differentiation, while downregulation of EVL inhibited it. In addition, EVL activated the JNK pathway and phosphorylation of p38 MAPK during differentiation procedure of hDPSCs. The EVL-enhanced differentiation of DPSCs was suppressed by blocking the JNK pathway, rather than the p38 MAPK pathway. EVL promotes the osteo-/odontogenic differentiation of hDPSCs by activating the JNK pathway, providing a future target for osteo-/odontogenic differentiation and dental pulp regeneration.

Effects of p16/pRb and JNK signaling pathways in hydroquinone-induced malignant transformation of TK6 cells

Objective: To investigate the cell cycle and apoptosis in hydroquinone (HQ) -induced malignant transformation of TK6 cells and its related regulatory mechanisms. Methods: TK6 cells were exposed to 20 μmol/L HQ, 24 h/time, once a week, for 19 weeks as experimental group and TK6 cells treated with phosphate buffer (PBS) for 19 weeks was used as control group from March 2014. In regulatory mechanism research, the cells were divided into four groups: control group, experimental group, control inhibitor group and experimental inhibitor group (inhibitor groups were added 10 μmol/L P600125) . Cell cycle and apoptosis were detected by flow cytometry. The protein expression of cell cycle-related proteins and JNK signaling pathway proteins were detected by Western blot. Results: Flow cytometry showed that compared with control group, the ratio of cells in the G0/G1 phase of the experimental group was significantly decreased (P=0.001) , and the ratio of cells in the S phase was significantly increased (P=0.002) . Western blotting demonstrated that the protein expressions of p-Rb (Ser780) , E2F1, Cyclin D1, p-p16 (Ser152) , JNK1, p-JNK1 (Thr183/Tyr185) , c-jun, p-c-jun (Ser63) (P=0.015, 0.021, 0.001, 0.001, 0.005, 0.001, 0.039, 0.003) were up-regulated, while the protein expressions of Rb (P=0.048) and p16 (P=0.002) were significantly down-regulated. After exposed to SP600125, compared with experimental group, there were no significant changes in cell cycle distribution (P=0.946) and apoptosis rate (P=0.923) in experimental inhibitor group. The expression of c-jun (P=0.040) protein was down-regulated, while the expression of Rb (P=0.027) protein was up-regulated in experimental inhibitor group. Conclusion: In HQ-induced TK6 cells malignant transformation, the cell cycle is arrested in the S phase, and the p16/pRb signaling pathway is inhibited, while the JNK signaling pathway is activated. However, the activated JNK signaling pathway may not be involved in the regulation of cell cycle.

ANLN Serves as an Oncogene in Bladder Urothelial Carcinoma via Activating JNK Signaling Pathway

Introduction: To understand the significance of ANLN (anillin, actin-binding protein)-mediated c-Jun N-terminal kinase (JNK) signal pathway on the progression of bladder urothelial carcinoma (BLCA). Methods: The Cancer Genome Atlas (TCGA) database was utilized to perform the clinical significance of ANLN in BLCA. Then, ANLN expression was determined in human normal primary bladder epithelial cells (BdEC) and BLCA cells. Later, ANLN knockdown was performed in BLCA cells, where the expression of MAPK8, MAPK9, and p-JNK/JNK was detected. BLCA cells were divided into the Mock, siNC, siANLN, SP600125 (a selective JNK inhibitor), and ANLN + SP600125 group, followed by measurements of real-time quantitative polymerase chain reaction, 3-4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, Annexin V-FITC/PI, Wound-healing, Transwell, and immunofluorescence assays. Results: ANLN was upregulated in the BLCA tissues, which showed a relation with the stage of patients. Besides, BLCA patients with high expression of ANLN had a worse prognosis than those with low expression of ANLN. Besides, the expression of ANLN in the BLCA tissues was positively correlated with MAPK8 and MAPK9. SP600125 suppressed the JNK signal pathway, reduced the proliferation, and increased BLCA cell apoptosis, with the reductions in the invasion and migration and the upregulation of phospho-histone H3 Ser-10 (pHH3), which was abolished by the overexpression of ANLN. Conclusion: ANLN, as an oncogene of BLCA, may associate with the activation of JNK signal pathway. Inhibiting ANLN could deactivate the JNK signal pathway, thereby suppressing the proliferation, invasion, and migration while promoting the apoptosis of BLCA cells.

Isoalantolactone Enhances the Antitumor Activity of Doxorubicin by Inducing Reactive Oxygen Species and DNA Damage.

Colon cancer is one of the most common cancer in the world. Doxorubicin (DOX) is a classical anti-tumor drug which widely used in treatment of cancers, however, high toxicity limited its further clinical application. Thus, it is urgent to find new drugs with low toxicity and high efficiency to treat colon cancer. Isoalantolactone (IATL), an isomeric sesquiterpene lactone isolated from the plant of inula helenium, has been reported to have anti-cancer activity against a variety of cancer cells. However, the function of IATL in colon cancer remains unclear. Here, we demonstrated that IATL inhibited colon cancer cell growth by increasing cellular reactive oxygen species (ROS) production. Further study showed that ROS accumulation contributed to DNA damage and JNK signaling pathway activation. In addition, we found that IATL markedly enhanced DOX-induced cell cytotoxicity in colon cancer cells. IATL in combination with DOX significantly increased the ROS production, induced DNA damage and activated JNK signaling pathway. Taken together, our data suggested that combined treatment with IATL and DOX may serve as a potential therapeutics for colon cancer.

Nanosecond pulsed electric fields prime mesenchymal stem cells to peptide ghrelin and enhance chondrogenesis and osteochondral defect repair in vivo.

Mesenchymal stem cells (MSCs) are important cell sources in cartilage tissue development and homeostasis, and multiple strategies have been developed to improve MSCs chondrogenic differentiation with an aim of promoting cartilage regeneration. Here we report the effects of combining nanosecond pulsed electric fields (nsPEFs) followed by treatment with ghrelin (a hormone that stimulates release of growth hormone) to regulate chondrogenesis of MSCs. nsPEFs and ghrelin were observed to separately enhance the chondrogenesis of MSCs, and the effects were significantly enhanced when the bioelectric stimulation and hormone were combined, which in turn improved osteochondral tissue repair of these cells within Sprague Dawley rats. We further found that nsPEFs can prime MSCs to be more receptive to subsequent stimuli of differentiation by upregulated Oct4/Nanog and activated JNK signaling pathway. Ghrelin initiated chondrogenic differentiation by activation of ERK1/2 signaling pathway, and RNA-seq results indicated 243 genes were regulated, and JAK-STAT signaling pathway was involved. Interestingly, the sequential order of applying these two stimuli is critical, with nsPEFs pretreatment followed by ghrelin enhanced chondrogenesis of MSCs in vitro and subsequent cartilage regeneration in vivo, but not vice versa. This synergistic prochondrogenic effects provide us new insights and strategies for future cell-based therapies.

Prevention of acetaminophen-induced hepatocyte injury: JNK inhibition and GSTA1 involvement

Glutathione S-transferase A1 (GSTA1) is a detoxification enzyme and a sensitive marker for hepatotoxicity. We investigated the effects of JNK inhibition on different degrees of Acetaminophen (APAP)-induced hepatocyte injury and GSTA1 expression. This study aimed to investigate the role of JNK signaling pathway in APAP-induced different degrees of hepatocyte injury and its correlation with GSTA1 by inhibiting the phosphorylation of JNK by SP600125. 6 and 8 mM APAP induced different degrees of hepatocyte injury and apoptosis, both activated JNK signaling pathway. In contrast, JNK inhibitor significantly reduced activation of JNK and c-JUN on exposure to APAP. Meanwhile, the levels of hepatocyte injury, oxidative stress, and apoptosis obviously decreased. Importantly, GSTA1 expression was significantly increased by JNK inhibition. JNK inhibition attenuates APAP-induced hepatocyte injury and oxidative stress and increases GSTA1 expression. Furthermore, GSTA1 may be involved in this signaling pathway for detoxification.

The regulatory role of SFRP5/WNT5A axis in allergic rhinitis through inhibiting JNK pathway activation and lowering mucin generation in human nasal epithelial cells

Allergic rhinitis (AR) is tightly associated with type 2 inflammation. SFRP5 combined with WNT5A mainly inhibits chronic inflammatory response, atherosclerosis, and other metabolic disorders. However, the effect of SFRP5/WNT5A axis on recombinant human interleukin-13 (rhIL-13)-induced inflammation has not been studied. In this study, we aimed to investigate whether secreted frizzled-related protein 5 (SFRP5) could modulate the production of cytokines relevant to eosinophil infiltration and mucin secretion through blocking the activation of Wnt family 5A (WNT5A) signaling pathway. A mouse model of AR demonstrated low expression of SFRP5 and high expression of WNT5A, and indicated that the number of eosinophil and goblet cells was increased, concomitant with elevated IL-13, colony stimulating factor 2 (CSF2), chemokine ligand 11 (CCL11), Mucin 4, and Mucin 5AC levels. Furthermore, lentivirus-SFRP5 overexpression up-regulated the expression of SFRP5 but down-regulated WNT5A level, and inhibited the activation of JNK pathway via decreasing p-JNK1/2 (Thr183/Tyr185) and p-c-Jun (Ser73) protein expressions in rhIL-13-treated human nasal epithelial cells (HNEpCs). Noticeably, SFRP5 overexpression markedly reduced rhIL-13-induced inflammatory protein and mucin generation through lowered CSF2, CCL11, Mucin 4, as well as Mucin 5AC levels. Taken together, these findings confirmed the regulatory role of SFRP5/WNT5A axis in rhIL-13-mediated inflammatory response in HNEpCs.

The Interleukin-33/ST2 axis promotes glioma mesenchymal transition, stemness and TMZ resistance via JNK activation.

IL-33 is an important member of the IL-1 family which has pleiotropic activities in innate and adaptive immune responses. Recently, some researchers have focused on the function of cellular immunity in the development of tumor. The biological role of IL-33 in glioma is poorly understood. In this study, we showed that glioma cells and tissues expressed higher levels of IL-33 and its receptor ST2 compared to normal brain. Clinically, IL-33 expression was associated with poor survival in patients with glioma. Administration of human IL-33 enhanced cell migration, invasion, epithelial to mesenchymal transition and stemness. Anti-ST2 blocked these effects of IL-33 on tumor. Mechanistically, IL-33 activated JNK signaling pathway via ST2 and increased the expression of key transcription factors that controlled the process of EMT and stemness. Moreover, IL-33 prevented temozolomide induced tumor apoptosis. Anti-ST2 or knockdown IL-33 increased the sensitivity of tumor to temozolomide. Thus, targeting the IL-33/ST2 axis may offer an opportunity to the treatment of glioma patients.

Coronarin D suppresses proliferation, invasion and migration of glioma cells via activating JNK signaling pathway

Coronarin D (CD) is one of the primary components of the Hedychium coronarium rhizomes and possesses strong anticancer effects via preventing cell growth in many cancer cells. The study was aimed to explore the molecular mechanisms underlying effects of CD on proliferation, invasion and migration of gliomas cells. Gliomas cell lines U251 was employed for detecting cells viability and proliferation by Cell Counting Kit-8 assay and colony formation assay. In addition, scratch wound healing and transwell assays were performed for the analysis of U251 cells invasion and migration respectively. Furthermore, the expression of p-Akt/Akt, p-p38/p38, p-ERK/ERK, p-JNK/JNK, p-STAT3/STAT3, cyclinE, cyclinD1, CTGF, MMP-2 and MMP-9 were measured by Western blotting. CD could suppress proliferation, invasion and migration of glioma cells and induced reduction of cyclinE, cyclinD1, CTGF, MMP-2 and MMP-9 expression via activating JNK signaling pathway. CD treatment suppressed expression of p-AKT, p38, and ERK and elevated expression of p-JNK in concentration- and time-dependent manners. Moreover, CD significantly induced reduction of phosphorylated STAT3 expression. Exposure of cells to the JNK-specific inhibitor SP600125 reduced the cytotoxicity effects of CD, combination of CD and SP600125 corrected overexpression of phosphorylated JNK and reduction of phosphorylated STAT3. Pretreatment of SP600125 also improves gliomas cells viability and invasion. The results revealed that CD may remarkably suppress gliomas cell growth through JNK and STAT3 signaling. In present study, these findings revealed that CD induces suppression of cell viability in gliomas cells and possesses therapeutic effect on gliomas.

RETRACTED: ANXA3 Silencing Ameliorates Intracranial Aneurysm via Inhibition of the JNK Signaling Pathway

Intracranial aneurysm (IA) rupture is a major cause of stroke death. Alteration of vascular smooth muscle cell (VSMC) function and phenotypic modulation plays a role in aneurysm progression. In the present study, we investigated the role of Annexin A3 (ANXA3) silencing in IA with the interaction of the c-Jun N-terminal kinase (JNK) signaling pathway. In IA and VSMCs of IA, the relationship between ANXA3 and the JNK signaling pathway was verified. To investigate the specific mechanism of ANXA3 silencing in IA, we transfected VSMCs with the overexpressed or small interfering RNA (siRNA) of ANXA3, or treated them with an inhibitor of the JNK signaling (SP600125). Cell counting kit-8 (CCK-8) assay was conducted to detect cell viability, and flow cytometry was conducted to assess cell cycle and apoptosis so as to evaluate the gain- and loss-of-function of ANXA3 and investigate the involvement of the JNK signaling pathway. The aneurysm wall of IA cells demonstrated an elevated level of ANXA3 expression and an activated JNK signaling pathway. VSMCs treated with siRNA-ANXA3 or SP600125 showed decreased expression of JNK, caspase-3, osteopontin (OPN), Bax, and matrix metalloproteinase-9 (MMP-9), as well as phosphate (p)-JNK, but increased the expression of α smooth muscle actin (α-SMA), β-tubulin, and Bcl-2. ANXA3 silencing or inactivation of the JNK signaling pathway also enhanced proliferation and repressed apoptosis of VSMCs. Collectively, this study shows that the silencing of ANXA3 can rescue VSMC function in IAs by inhibiting the phosphorylation and activation of the JNK signaling pathway. These findings may provide a potential therapy for the molecular treatment of IAs.

Liraglutide promotes apoptosis of HepG2 cells by activating JNK signaling pathway.

To study the effect and mechanism of liraglutide on the apoptosis of human hepatocellular carcinoma HepG2 cells. HepG2 cell was treated with different concentrations of liraglutide at 0, 1, 10, 100, and 1000 nmol/L. The effect of liraglutide on HepG2 proliferation was detected by Cell Counting Kit-8 (CCK-8) method; the effect of liraglutide on the protein expression of c-Jun NH2-terminal Kinase (JNK) and phosphorylated JNK (p-JNK) was detected by Western blot; the degree of HepG2 apoptosis was observed by flow cytometry, and JNK pathway blocker SP600125 was used to further confirm that liraglutide promoted HepG2 apoptosis by regulating JNK signaling pathway. The proliferation inhibition rate of HepG2 cells increased with time and the increase in the concentration of liraglutide. The proliferation inhibition rate was the strongest when cultured for 48 h, and the IC50 (half maximal inhibitory concentration) was about 100 nmol/L of liraglutide. 100 nmol/L liraglutide was selected as the intervention condition for subsequent use of SP600165. The apoptosis rate of HepG2 cells increased with the increase of liraglutide's concentration. The apoptosis rate of HepG2 cells at blocker SP600125+100 nmol/L liraglutide was significantly lower than that at 100 nmol/L liraglutide alone (p<0.05). There was no significant difference in the expression of JNK protein in HepG2 cells at different concentrations of liraglutide (p>0.05). There was no significant difference in the expression of JNK protein in HepG2 cells using JNK pathway blocker SP600125 (p>0.05), while using JNK pathway blocker SP600125 significantly up-regulated the expression of p-JNK protein in HepG2 cells than 100 nmol/L of liraglutide alone (p<0.05). Liraglutide can promote the apoptosis of hepatocellular carcinoma HepG2 cells in a dose-dependent manner, and its mechanism may act by promoting the activation of the JNK signaling pathway.

Study on effect and mechanism of Honokiol enhancing tumor necrosis factor-related apoptosis inducing ligand against hepatocellular carcinoma HepG2 cells via activating JNK signaling pathway

Objective: To investigate the effect and intrinsic mechanism of Honokiol (HNK) enhanced tumor necrosis factor-related apoptosis inducing ligand (TRAIL) on hepatocellular carcinoma HepG2 cells. Methods: HepG2 cells were routinely cultured. Firstly, a concentration gradient of HNK was given to observe its effect on the vitality of tumor cells. Western blot were used to detect change in the expression levels of c-jun N-terminal kinase (JNK), death receptor 4 (DR4), and DR5.Secondly, we observed the effect of combined drugs (HNK and TRAIL) on the vitality of tumor cells. Apoptosis-related protein expression levels were detected to determine the apoptosis condition. Thirdly, JNK inhibitor SP600125 was used to block the JNK pathway, and it was evaluated whether JNK signaling pathway mediated the DR4 and DR5 levels and finally, the subcutaneous tumor model of nude mice was constructed, and enhancement effect of HNK on TRAIL was confirmed in vivo. Results: Cell vitality was decreased (P < 0.05) in a dose-dependent manner after treatment with gradient HNK. Combined effect of TRAIL and HNK was superior to that of single drug administration (P < 0.05). Western blot analysis showed that pJNK level increased after HNK treatment and TRAIL receptor DR4 and DR5 expression were up-regulated. Combined application of HNK and TRAIL, B lymphocyte tumor factor 2 (BCL2) decreased significantly while Bcl2 related X protein (Bax) increased significantly. Blocking JNK pathway by SP600125, the expression of DR4 and DR5 decreased (P < 0.05), Bax expression decreased and Bcl2 expression increased compared with HNK+TRAIL group. In vivo results showed that TRAIL inhibited the growth of subcutaneous tumors, and enhanced inhibition effect in combination with TRAIL and HNK. Conclusion: HNK may enhance the inhibitory effect of TRAIL on HepG2 cells by activating JNK pathway and then upregulating the expression of DR4 and DR5.

Bone morphogenetic protein 7 regulates insulin signal transduction in mice

Objective To analyze the effects of bone morphogenetic protein 7 (BMP 7) on insulin signaling pathway in mice and its involved molecular mechanisms. Methods To increase BMP7 expression in liver, adenovirus bearing BMP7 was injected into mice via tail vein. The impact of BMP7 overexpression on glucose metabolism was assayed by glucose tolerance test and insulin tolerance test. The levels of proteins involved in insulin signaling pathway and c-Jun N-terminal kinase (JNK) signaling pathway were analyzed by Western blot. Results The blood glucose level was increased by BMP7 overexpression (P<0.05), while the glucose tolerance and insulin tolerance were decreased by BMP7. The p-Akt and p-GSK3β in liver and epididymal white adipose tissue (WAT) were reduced in the BMP7-overexpressed mice (P<0.01), indicating insulin signal transduction was inhibited. In gastrocnemius muscle, the insulin signal transduction was not altered by BMP7. Mechanistically, the JNK pathway was activated by BMP7 in liver and epididymal WAT (P<0.01), while the JNK pathway in skeletal muscle was not changed. Conclusions In mice, BMP7 elevated blood sugar and decreased glucose and insulin tolerance. BMP7 inhibited the insulin signaling pathway in liver and WAT. These inhibitory effects on insulin signaling pathway was likely to be achieved by an activating JNK signaling pathway. (Chin J Endocrinol Metab, 2018, 34: 398-403) Key words: Bone morphogenetic protein 7; Insulin signaling transduction; JNK; Insulin resistance; Diabetes mellitus, experimental

Cordyceps militaris Fraction induces apoptosis and G2/M Arrest via c-Jun N-Terminal kinase signaling pathway in oral squamous carcinoma KB Cells.

Background:Cordyceps militaris fraction (CMF) has been shown to possess in vitro antitumor activity against human chronic myeloid leukemia K562 cells in our previous research. Materials and Methods:The in vitro inhibitory activities of CMF on the growth of KB cells were evaluated by viability assay. The apoptotic and cell cycle influences of CMF were detected by 4′,6-diamidino-2-phenylindole staining and flow cytometry assay. The expression of different apoptosis-associated proteins and cell cycle regulatory proteins was examined by Western blot assay. The nuclear localization of c-Jun was observed by fluorescence staining.Objective:The objective of this study was to investigate the antiproliferative effect of CMF as well as the mechanism underlying the apoptosis and cell cycle arrest it induces in KB cells.Results:CMF suppressed KB cells’ proliferation in a dose- and time-dependent manner. Flow cytometric analysis indicated that CMF induced G2/M cell cycle arrest and apoptosis. Western blot analysis revealed that CMF induced caspase-3, caspase-9, and PARP cleavages, and increased the Bax/Bcl-2 ratio. CMF also led to increased expression of p21, decreased expression of cyclin B1, mitotic phosphatase cdc25c, and mitotic kinase cdc2, as well as unchanged expression of p53. In addition, CMF stimulated c-Jun N-terminal kinases (JNK) protein phosphorylations, resulting in upregulated expression of c-Jun and nuclear localization of c-Jun. Pretreatment with JNK inhibitor SP600125 suppressed CMF-induced apoptosis and G2/M arrest.Conclusions:CMF is capable of modulating c-Jun caspase and Bcl-2 family proteins through JNK-dependent apoptosis, which results in G2/M phase arrest in KB cells. CMF could be developed as a promising candidate for the new antitumor agents.SUMMARY CMF exhibited strong anticancer activity against oral squamous carcinoma KB cellsCMF inhibited KB cells’ proliferation via induction of apoptosis and G2/M cell cycle arrestCMF activated JNK signaling pathway and promoted the nuclear localization of c-JunCMF regulated the apoptosis- and cell cycle-related proteins in a manner dependent on JNK/c-Jun pathway. Abbreviations used: CMF: Cordyceps militaris fraction; OSCC: Oral squamous cell carcinoma; JNK: c-Jun N-terminal kinase.

The CCL17-CCR4 axis between endometrial stromal cells and macrophages contributes to the high levels of IL-6 in ectopic milieu.

Endometriosis is a chronic inflammatory disease characterized by the elevation of proinflammatory cytokines, such as IL-6, in the peritoneal fluid. However, the precise mechanism of the highly elevated IL-6 levels in ectopic milieu remains unclear. The aim of this study was to investigate whether the cross talk between endometrial stromal cells (ESCs) and macrophages contributes to the elevated IL-6 production. Samples of endometrium and ectopic tissues were obtained from patients with or without endometriosis. The peripheral blood samples were collected from healthy volunteers. Enzyme-linked immunosorbent assay (ELISA) was for IL-6 levels in peritoneal fluid and cell culture supernatant. In-Cell Western assay was used for protein expression of CCL17 and phosphorylation levels of ERK, JNK, and P38. Immunohistochemistry was performed on normal, eutopic endometrium and ectopic tissues to analyze CCL17 expression. Flow cytometry was applied to detect the expression of CCR4, IL-6, and the phosphorylation levels of NF-κB. Patients with endometriosis have higher levels of IL-6 in peritoneal fluid compared to the control. The co-culture of ESCs and macrophages produce more IL-6 than cultured alone, respectively. The eutopic endometrium had significantly higher expression of CCL17 compared to normal endometrium, and the ectopic tissues had the highest expression. IL-6 induced CCL17 secretion in ESCs via activating JNK signaling pathway, CCL17 upregulated the expression of its receptor CCR4 on macrophages. Furthermore, CCL17-CCR4 axis subsequently led to excessive IL-6 production in macrophages by activating NF-κB. These findings suggest that the cross talk between ESCs and macrophages promotes the expression of CCL17 in ESCs and CCR4 on macrophages, which contributes to the high levels of IL-6 in ectopic milieu.

Etoposide Induces Apoptosis in Activated Human Hepatic Stellate Cells via ER Stress.

The activation of hepatic stellate cells (HSCs) plays a vital role in the progression of liver fibrosis, and the induction of HSCs apoptosis may attenuate or reverse fibrogenesis. The therapeutic effects of etoposide(VP-16), a widely used anticancer agent, on HSCs apoptosis and liver fibrosis resolution are still unclear. Here, we report that VP-16 reduced the proliferation of LX-2 cells and led to significantly high levels of apoptosis, as indicated by Annexin V staining and the proteolytic cleavage of the executioner caspase-3 and PARP. Additionally, the unfolded protein response regulators CHOP, BIP, caspase-12, p-eIF2α and IRE1α, which are considered endoplasmic reticulum (ER) stress markers, were upregulated by VP-16. The strong inhibitory effect of VP-16 on LX-2 cells was mainly dependent on ER stress, which activated JNK signaling pathway. Remarkably, VP-16 treatment decreased the expression of α-SMA and type I collagen and simultaneously increased the ratio of matrix metalloproteinases (MMPs) to tissue inhibitor of matrix metalloproteinases (TIMPs). In contrast, VP-16 induced significantly more apoptosis in HSCs than in normal hepatocytes. Taken together, our findings demonstrate that VP-16 exerts a proapoptotic effect on LX-2 cells and has an antifibrogenic effect on collagen deposition, suggesting a new strategy for the treatment of liver fibrosis.

Gambogic acid inhibits growth, induces apoptosis, and overcomes drug resistance in human colorectal cancer cells.

The emergence of chemoresistance is a major limitation of colorectal cancer (CRC) therapies and novel biologically based therapies are urgently needed. Natural products represent a novel potential anticancer therapy. Gambogic acid (GA), a small molecule derived from Garcinia hanburyi Hook. f., has been demonstrated to be highly cytotoxic to several types of cancer cells and have low toxicity to the hematopoietic system. However, the potential role of GA in colorectal cancer and its ability to overcome the chemotherapeutic resistance in CRC cells have not been well studied. In the present study, we showed that GA directly inhibited proliferation and induced apoptosis in both 5-fluorouracil (5-FU) sensitive and 5-FU resistant colorectal cancer cells; induced apoptosis via activating JNK signaling pathway. The data, therefore, suggested an alternative strategy to overcome 5-FU resistance in CRC and that GA could be a promising medicinal compound for colorectal cancer therapy.

ZnO nanoparticle-induced oxidative stress triggers apoptosis by activating JNK signaling pathway in cultured primary astrocytes

It has been documented in in vitro studies that zinc oxide nanoparticles (ZnO NPs) are capable of inducing oxidative stress, which plays a crucial role in ZnO NP-mediated apoptosis. However, the underlying molecular mechanism of apoptosis in neurocytes induced by ZnO NP exposure was not fully elucidated. In this study, we investigated the potential mechanisms of apoptosis provoked by ZnO NPs in cultured primary astrocytes by exploring the molecular signaling pathways triggered after ZnO NP exposure. ZnO NP exposure was found to reduce cell viability in MTT assays, increase lactate dehydrogenase (LDH) release, stimulate intracellular reactive oxygen species (ROS) generation, and elicit caspase-3 activation in a dose- and time-dependent manner. Apoptosis occurred after ZnO NP exposure as evidenced by nuclear condensation and poly(ADP-ribose) polymerase-1 (PARP) cleavage. A decrease in mitochondrial membrane potential (MMP) with a concomitant increase in the expression of Bax/Bcl-2 ratio suggested that the mitochondria also mediated the pathway involved in ZnO NP-induced apoptosis. In addition, exposure of the cultured cells to ZnO NPs led to phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-related kinase (ERK), and p38 mitogen-activated protein kinase (p38 MAPK). Moreover, JNK inhibitor (SP600125) significantly reduced ZnO NP-induced cleaved PARP and cleaved caspase-3 expression, but not ERK inhibitor (U0126) or p38 MAPK inhibitor (SB203580), indicating that JNK signaling pathway is involved in ZnO NP-induced apoptosis in primary astrocytes.