Signal transducer and activator of transcription 3 activation up-regulates interleukin-6 autocrine production: a biochemical and genetic study of established cancer cell lines and clinical isolated human cancer cells

Defective N-glycosylation of IL6 induces metastasis and tyrosine kinase inhibitor resistance in lung cancer

The IL6-GP130-STAT3 pathway facilitates lung cancer progression and resistance to tyrosine kinase inhibitors. Although glycosylation alters the stability of GP130, its effect on the ligand IL6 remains unclear. We herein find that N-glycosylated IL6, especially at Asn73, primarily stimulates JAK-STAT3 signaling and prolongs STAT3 phosphorylation, whereas N-glycosylation-defective IL6 (deNG-IL6) induces shortened STAT3 activation and alters the downstream signaling preference for the SRC-YAP-SOX2 axis. This signaling shift induces epithelial-mesenchymal transition (EMT) and migration in vitro and metastasis in vivo, which are suppressed by targeted inhibitors and shRNAs against SRC, YAP, and SOX2. Osimertinib-resistant lung cancer cells secrete a large amount of deNG-IL6 through reduced N-glycosyltransferase gene expression, leading to clear SRC-YAP activation. deNG-IL6 contributes to drug resistance, as confirmed by in silico analysis of cellular and clinical transcriptomes and signal expression in patient specimens. Therefore, the N-glycosylation status of IL6 not only affects cell behaviors but also shows promise in monitoring the dynamics of lung cancer evolution.

p27 specifically decreases in squamous carcinoma, and mediates NNK-induced transformation of human bronchial epithelial cells

Lung cancer remains the leading cause of cancer-related deaths, with cigarette smoking being the most critical factor, linked to nearly 90% of lung cancer cases. NNK, a highly carcinogenic nitrosamine found in tobacco, is implicated in the lung cancer-causing effects of cigarette smoke. Although NNK is known to mutate or activate certain oncogenes, its potential interaction with p27 in modulating these carcinogenic effects is currently unexplored. Recent studies have identified specific downregulation of p27 in human squamous cell carcinoma, in contrast to adenocarcinoma. Additionally, exposure to NNK significantly suppresses p27 expression in human bronchial epithelial cells. Subsequent studies indicates that the downregulation of p27 is pivotal in NNK-induced cell transformation. Mechanistic investigations have shown that reduced p27 expression leads to increased level of ITCH, which facilitates the degradation of Jun B protein. This degradation in turn, augments miR-494 expression and its direct regulation of JAK1 mRNA stability and protein expression, ultimately activating STAT3 and driving cell transformation. In summary, our findings reveal that: (1) the downregulation of p27 increases Jun B expression by upregulating Jun B E3 ligase ITCH, which then boosts miR-494 transcription; (2) Elevated miR-494 directly binds to 3'-UTR of JAK1 mRNA, enhancing its stability and protein expression; and (3) The JAK1/STAT3 pathway is a downstream effector of p27, mediating the oncogenic effect of NNK in lung cancer. These findings provide significant insight into understanding the participation of mechanisms underlying p27 inhibition of NNK induced lung squamous cell carcinogenic effect.

Importance of IL-6 trans-signaling and high autocrine IL-6 production in human osteoarthritic chondrocyte metabolism

OBJECTIVE

Neutralization of Interleukin (IL)-6-signaling by antibodies is considered a promising tool for the treatment of osteoarthritis (OA). To gain further insight into this potential treatment, this study investigated the effects of IL-6-signaling and IL-6 neutralization on chondrocyte metabolism and the release of IL-6-signaling-related mediators by human chondrocytes.

DESIGN

Chondrocytes were collected from 49 patients with advanced knee/hip OA or femoral neck fracture. Isolated chondrocytes were stimulated with different mediators to analyze the release of IL-6, soluble IL-6 receptor (sIL-6R) and soluble gp130 (sgp130). The effect of IL-6 and IL-6/sIL-6R complex as well as neutralization of IL-6-signaling on the metabolism was analyzed.

RESULTS

OA chondrocytes showed high basal IL-6 production and release, which was strongly negatively correlated with the production of cartilage-matrix-proteins. Chondrocytes produced and released sIL-6R and sgp130. The IL-6/sIL-6R complex significantly increased nitric oxide, prostaglandin E2 and matrix metalloproteinase 1 production, decreased Pro-Collagen Type II and mitochondrial ATP production, and increased glycolysis in OA chondrocytes. Neutralization of IL-6-signaling by antibodies did not significantly affect the metabolism of OA chondrocytes, but blocking of glycoprotein 130 (gp130)-signaling by SC144 significantly reduced the basal IL-6 release.

CONCLUSION

Although IL-6 trans-signaling induced by IL-6/sIL-6R complex negatively affects OA chondrocytes, antibodies against IL-6 or IL-6R did not affect chondrocyte metabolism. Since inhibition of gp130-signaling reduced the enhanced basal release of IL-6, interfering with gp130-signaling may ameliorate OA progression because high cellular release of IL-6 correlates with reduced production of cartilage-matrix-proteins.

Ginsenoside Re protects against kainate-induced neurotoxicity in mice by attenuating mitochondrial dysfunction through activation of the signal transducers and activators of transcription 3 signaling

It was demonstrated that ginsenosides exert anti-convulsive potentials and interleukin-6 (IL-6) is protective from excitotoxicity induced by kainate (KA), a model of temporal lobe epilepsy. Ginsenosides-mediated mitochondrial recovery is essential for attenuating KA-induced neurotoxicity, however, little is known about the effects of ginsenoside Re (GRe), one of the major ginsenosides. In this study, GRe significantly attenuated KA-induced seizures in mice. KA-induced redox changes were more evident in mitochondrial fraction than in cytosolic fraction in the hippocampus of mice. GRe significantly attenuated KA-induced mitochondrial oxidative stress (i.e. increases in reactive oxygen species, 4-hydroxynonenal, and protein carbonyl) and mitochondrial dysfunction (i.e. the increase in intra-mitochondrial Ca2+ and the decrease in mitochondrial membrane potential). GRe or mitochondrial protectant cyclosporin A restored phospho-signal transducers and activators of transcription 3 (STAT3) and IL-6 levels reduced by KA, and the effects of GRe were reversed by the JAK2 inhibitor AG490 and the mitochondrial toxin 3-nitropropionic acid (3-NP). Thus, we used IL-6 knockout (KO) mice to investigate whether the interaction between STAT3 and IL-6 is involved in the GRe effects. Importantly, KA-induced reduction of manganese superoxide dismutase (SOD-2) levels and neurodegeneration (i.e. astroglial inhibition, microglial activation, and neuronal loss) were more prominent in IL-6 KO than in wild-type (WT) mice. These KA-induced detrimental effects were attenuated by GRe in WT and, unexpectedly, IL-6 KO mice, which were counteracted by AG490 and 3-NP. Our results suggest that GRe attenuates KA-induced neurodegeneration via modulating mitochondrial oxidative burden, mitochondrial dysfunction, and STAT3 signaling in mice.

Autocrine Regulation of Interleukin-6 via the Activation of STAT3 and Akt in Cardiac Myxoma Cells

Plasma concentrations of a pleiotropic cytokine, interleukin (IL)-6, are increased in patients with cardiac myxoma. We investigated the regulation of IL-6 in cardiac myxoma. Immunohistochemical staining and reverse transcription-polymerase chain reaction (RT-PCR) revealed that IL-6 and its receptors, IL-6 receptor (IL-6R) and gp130, co-existed in the myxoma cells. Myxoma cells were cultured, and an antibody array assay showed that a conditioned medium derived from the cultured myxoma cells contained increased amounts of IL-6. Signal transducer and activator of transcription (STAT) 3 and Akt were constitutively phosphorylated in the myxoma cells. An enzyme-linked immunosorbent assay (ELISA) showed that the myxoma cells spontaneously secreted IL-6 into the culture medium. Real-time PCR revealed that stimulation with IL-6 + soluble IL-6R (sIL6R) significantly increased IL-6 mRNA in the myxoma cells. Pharmacological inhibitors of STAT3 and Akt inhibited the IL-6 + sIL-6R-induced gene expression of IL-6 and the spontaneous secretion of IL-6. In addition, IL-6 + sIL-6R-induced translocation of phosphorylated STAT3 to the nucleus was also blocked by STAT3 inhibitors. This study has demonstrated that IL-6 increases its own production via STAT3 and Akt pathways in cardiac myxoma cells. Autocrine regulation of IL-6 may play an important role in the pathophysiology of patients with cardiac myxoma.

The BK Channel Limits the Pro-Inflammatory Activity of Macrophages

Macrophages play a crucial role in the innate immune response, serving as key effector cells in the defense against pathogens. Although the role of the large-conductance voltage and calcium-activated potassium channel, also known as the KCa1.1 or BK channel, in regulating neurotransmitter release and smooth muscle contraction is well known, its potential involvement in immune regulation remains unclear. We employed BK-knockout macrophages and noted that the absence of a BK channel promotes the polarization of macrophages towards a pro-inflammatory phenotype known as M1 macrophages. Specifically, the absence of the BK channel resulted in a significant increase in the secretion of the pro-inflammatory cytokine IL-6 and enhanced the activity of extracellular signal-regulated kinases 1 and 2 (Erk1/2 kinases), Ca2+/calmodulin-dependent protein kinase II (CaMKII), and the transcription factor ATF-1 within M1 macrophages. Additionally, the lack of the BK channel promoted the activation of the AIM2 inflammasome without affecting the activation of the NLRC4 and NLRP3 inflammasomes. To further investigate the role of the BK channel in regulating AIM2 inflammasome activation, we utilized BK channel inhibitors, such as paxilline and iberiotoxin, along with the BK channel activator NS-11021. Pharmacological inactivation of the BK channel increased, and its stimulation inhibited IL-1β production following AIM2 inflammasome activation in wild-type macrophages. Moreover, wild-type macrophages displayed increased calcium influx when activated with the AIM2 inflammasome, whereas BK-knockout macrophages did not due to the impaired extracellular calcium influx upon activation. Furthermore, under conditions of a calcium-free medium, IL-1β production following AIM2 inflammasome activation was increased in both wild-type and BK-knockout macrophages. This suggests that the BK channel is required for the influx of extracellular calcium in macrophages, thus limiting AIM2 inflammasome activation. In summary, our study reveals a regulatory role of the BK channel in macrophages under inflammatory conditions.

Dynamic IL-6R/STAT3 signaling leads to heterogeneity of metabolic phenotype in pancreatic ductal adenocarcinoma cells

Malignancy is enabled by pro-growth mutations and adequate energy provision. However, global metabolic activation would be self-terminating if it depleted tumor resources. Cancer cells could avoid this by rationing resources, e.g., dynamically switching between "baseline" and "activated" metabolic states. Using single-cell metabolic phenotyping of pancreatic ductal adenocarcinoma cells, we identify MIA-PaCa-2 as having broad heterogeneity of fermentative metabolism. Sorting by a readout of lactic acid permeability separates cells by fermentative and respiratory rates. Contrasting phenotypes persist for 4 days and are unrelated to cell cycling or glycolytic/respiratory gene expression; however, transcriptomics links metabolically active cells with interleukin-6 receptor (IL-6R)-STAT3 signaling. We verify this by IL-6R/STAT3 knockdowns and sorting by IL-6R status. IL-6R/STAT3 activates fermentation and transcription of its inhibitor, SOCS3, resulting in delayed negative feedback that underpins transitions between metabolic states. Among cells manifesting wide metabolic heterogeneity, dynamic IL-6R/STAT3 signaling may allow cell cohorts to take turns in progressing energy-intense processes without depleting shared resources.

Trinity of inflammation, innate immune cells and cross-talk of signalling pathways in tumour microenvironment

Unresolved inflammation is a pathological consequence of persistent inflammatory stimulus and perturbation in regulatory mechanisms. It increases the risk of tumour development and orchestrates all stages of tumorigenesis in selected organs. In certain cancers, inflammatory processes create the appropriate conditions for neoplastic transformation. While in other types, oncogenic changes pave the way for an inflammatory microenvironment that leads to tumour development. Of interest, hallmarks of tumour-promoting and cancer-associated inflammation are striking similar, sharing a complex network of stromal (fibroblasts and vascular cells) and inflammatory immune cells that collectively form the tumour microenvironment (TME). The cross-talks of signalling pathways initially developed to support homeostasis, change their role, and promote atypical proliferation, survival, angiogenesis, and subversion of adaptive immunity in TME. These transcriptional and regulatory pathways invariably contribute to cancer-promoting inflammation in chronic inflammatory disorders and foster "smouldering" inflammation in the microenvironment of various tumour types. Besides identifying common target sites of numerous cancer types, signalling programs and their cross-talks governing immune cells' plasticity and functional diversity can be used to develop new fate-mapping and lineage-tracing mechanisms. Here, we review the vital molecular mechanisms and pathways that establish the connection between inflammation and tumour development, progression, and metastasis. We also discussed the cross-talks between signalling pathways and devised strategies focusing on these interaction mechanisms to harness synthetic lethal drug combinations for targeted cancer therapy.

Blood transcriptome analysis suggests an indirect molecular association of early life adversities and adult social anxiety disorder by immune-related signal transduction

Social anxiety disorder (SAD) is a psychiatric disorder characterized by severe fear in social situations and avoidance of these. Multiple genetic as well as environmental factors contribute to the etiopathology of SAD. One of the main risk factors for SAD is stress, especially during early periods of life (early life adversity; ELA). ELA leads to structural and regulatory alterations contributing to disease vulnerability. This includes the dysregulation of the immune response. However, the molecular link between ELA and the risk for SAD in adulthood remains largely unclear. Evidence is emerging that long-lasting changes of gene expression patterns play an important role in the biological mechanisms linking ELA and SAD. Therefore, we conducted a transcriptome study of SAD and ELA performing RNA sequencing in peripheral blood samples. Analyzing differential gene expression between individuals suffering from SAD with high or low levels of ELA and healthy individuals with high or low levels of ELA, 13 significantly differentially expressed genes (DEGs) were identified with respect to SAD while no significant differences in expression were identified with respect to ELA. The most significantly expressed gene was MAPK3 (p = 0.003) being upregulated in the SAD group compared to control individuals. In contrary, weighted gene co-expression network analysis (WGCNA) identified only modules significantly associated with ELA (p ≤ 0.05), not with SAD. Furthermore, analyzing interaction networks of the genes from the ELA-associated modules and the SAD-related MAPK3 revealed complex interactions of those genes. Gene functional enrichment analyses indicate a role of signal transduction pathways as well as inflammatory responses supporting an involvement of the immune system in the association of ELA and SAD. In conclusion, we did not identify a direct molecular link between ELA and adult SAD by transcriptional changes. However, our data indicate an indirect association of ELA and SAD mediated by the interaction of genes involved in immune-related signal transduction.

Suppression of Platelet-Derived Growth Factor Receptor-Alpha Overcomes Resistance to Trastuzumab through STAT3-Dependent IL-6 Reduction in HER2-Positive Breast Cancer Cells

Platelet-derived growth factor receptor (PDGFR) plays an essential role in the proliferation and invasion of malignant cancer cells. However, the functional role of PDGFR alpha (PDGFRA) in HER2-positive (HER2+) breast cancer has not been fully clarified yet. Thus, the objective of this study was to investigate the clinical significance of PDGFRA and the therapeutic potential of PDGFR inhibitors as part of an effort to overcome trastuzumab (TRZ) resistance. Aberrant PDGFRA expression is closely associated with decreased survival in HER2+ breast cancers. Therefore, we established BT474 trastuzumab-sensitive (TRZ_S) and trastuzumab-resistant (TRZ_R) cells to investigate the association between PDGFR signaling and TRZ resistance. We found that PDGFRA was significantly upregulated in the BT474 TRZ_R cells. In addition, IL-6 expression, which was also found to be upregulated in the TRZ_R cells, was induced by PDGFC, a ligand of PDGFR. Next, we investigated the effects of ponatinib and sunitinib, PDGFR inhibitors, on the BT474 TRZ_R and HCC1954 (TRZ-resistant cell line) cells. These inhibitors decreased cell viability and migration in a dose-dependent manner. Additionally, IL-6 expression was decreased by ponatinib in both the BT474 TRZ_R and HCC1954 cells. In contrast, IL-6 was not suppressed by TRZ, implying that the PDGFRA/STAT3/IL-6 axis is associated with resistance to TRZ. In addition, we found that STAT3 and ERK phosphorylation were increased in the BT474 TRZ_R cells. IL-6 expression was suppressed by a STAT3 inhibitor, indicating that IL-6 expression is modulated downstream of STAT3. Taken together, these results suggest that PDGFRA could serve as a therapeutic target to overcome TRZ resistance.

TRAIL receptors promote constitutive and inducible IL-8 secretion in non-small cell lung carcinoma

Interleukin-8 (IL-8/CXCL8) is a pro-angiogenic and pro-inflammatory chemokine that plays a role in cancer development. Non-small cell lung carcinoma (NSCLC) produces high amounts of IL-8, which is associated with poor prognosis and resistance to chemo-radio and immunotherapy. However, the signaling pathways that lead to IL-8 production in NSCLC are unresolved. Here, we show that expression and release of IL-8 are regulated autonomously by TRAIL death receptors in several squamous and adenocarcinoma NSCLC cell lines. NSCLC constitutively secrete IL-8, which could be further enhanced by glucose withdrawal or by treatment with TRAIL or TNFα. In A549 cells, constitutive and inducible IL-8 production was dependent on NF-κB and MEK/ERK MAP Kinases. DR4 and DR5, known regulators of these signaling pathways, participated in constitutive and glucose deprivation-induced IL-8 secretion. These receptors were mainly located intracellularly. While DR4 signaled through the NF-κB pathway, DR4 and DR5 both regulated the ERK-MAPK and Akt pathways. FADD, caspase-8, RIPK1, and TRADD also regulated IL-8. Analysis of mRNA expression data from patients indicated that IL-8 transcripts correlated with TRAIL, DR4, and DR5 expression levels. Furthermore, TRAIL receptor expression levels also correlated with markers of angiogenesis and neutrophil infiltration in lung squamous carcinoma and adenocarcinoma. Collectively, these data suggest that TRAIL receptor signaling contributes to a pro-tumorigenic inflammatory signature associated with NSCLC.

Exosome-loaded hydrogels: a new cell-free therapeutic approach for skin regeneration

The treatment of unhealable and chronic cutaneous wounds is a significant challenge for the healthcare system. Hence, there has been heightened interest in the development of innovative therapeutic approaches for the acceleration of wound healing. Regenerative medicine based on mesenchymal stem cells (MSCs) has shown appropriate potential in skin repair. The regenerative properties of stem cells are mainly attributed to paracrine effects of secreted products, including exosomes. There are advantages to using exosomes as a cell-free approach instead of direct application of stem cells. Exosomes have nanoscale dimension and are immune-tolerant, Exosomes have the nanoscale dimension and are immune-tolerant. They can easily endocytose, and transfer the cargo content to recipient cells. They contribute to the regulation of the wound healing process by activating specific signaling pathways. To preserve exosome bioactivity and controlled release of effective concentration during prolonged wound care, the design of an optimized delivery system is necessary. Accordingly, hydrogels with their unique properties are promising candidates as exosome delivery and wound management products. This article investigates the characteristics of exosomes, their molecular mechanism in wound healing, and the advantages of the hydrogel delivery system. Also, published reports on the potential of exosome-loaded hydrogels in skin regeneration have been reviewed.

Resveratrol protects human nucleus pulposus cells from degeneration by blocking IL-6/JAK/STAT3 pathway

Background

Nucleus pulposus cells’ (NPCs’) degeneration is mainly responsible for the intervertebral disc degeneration (IDD), which is closely related to inflammatory response. Among the major proinflammatory factors that are related to NPCs’ degeneration, interleukin-6 (IL-6) and its downstream JAK/STAT3 pathway have received recent attention. The goal of our study is to figure out whether or how resveratrol (RSV) can protect NPCs from degeneration by affecting IL6/JAK/STAT3 pathway.

Methods

Different concentrations of RSV were added to NPCs’ mediums. Cell viability was measured by MTT assay and crystal violet staining. Cell cycle and apoptosis were analyzed by flow cytometry. Protein expression level was determined by western blot. mRNA expression level was measured by qPCR.

Results

Our study showed that RSV improved NPCs’ cell viability. It also inhibited cell apoptosis and cell cycle arrest, which were accompanied by the increased expression level of heat shock protein 90 (HSP90) and N-Cadherin. What’ more, RSV also improved the NPCs’ degeneration which was reflected in the increase of extracellular matrix (collagen II, Aggrecan). Moreover, RSV significantly attenuated the level of IL-6 secretion, which was accompanied by less phosphorylation of the transcription factors Janus kinase 1 (JAK1) and signal transducer and activator of transcription 3 (STAT3).

Conclusion

RSV exerted its protective effect on HNPCs’ degeneration by improving cell survival and function. The possible mechanism may be associated with the suppression of JAK/STAT3 phosphorylation and the decreased IL-6 production, which could be explained by a blockage of the positive feedback control loop between IL-6 and JAK/STAT3 pathway.

miR-4293 upregulates lncRNA WFDC21P by suppressing mRNA-decapping enzyme 2 to promote lung carcinoma proliferation

Non-coding RNAs (ncRNAs) involve in diverse biological processes by post-transcriptional regulation of gene expression. Emerging evidence shows that miRNA-4293 plays a significant role in the development of non-small cell lung cancer. However, the oncogenic functions of miR-4293 have not been studied. Our results demonstrated that miR-4293 expression is markedly enhanced in lung carcinoma tissue and cells. Moreover, miR-4293 promotes tumor cell proliferation and metastasis but suppresses apoptosis. Mechanistic investigations identified mRNA-decapping enzyme 2 (DCP2) as a target of miR-4293 and its expression is suppressed by miR-4293. DCP2 can directly or indirectly bind to WFDC21P and downregulates its expression. Consequently, miR-4293 can further promote WFDC21P expression by regulating DCP2. With a positive correlation to miR-4293 expression, WFDC21P also plays an oncogenic role in lung carcinoma. Furthermore, knockdown of WFDC21P results in functional attenuation of miR-4293 on tumor promotion. In vivo xenograft growth is also promoted by both miR-4293 and WFDC21P. Overall, our results establish oncogenic roles for both miR-4293 and WFDC21P and demonstrate that interactions between miRNAs and lncRNAs through DCP2 are important in the regulation of carcinoma pathogenesis. These results provided a valuable theoretical basis for the discovery of lung carcinoma therapeutic targets and diagnostic markers based on miR-4293 and WFDC21P.

Endothelial cells response to neutrophil-derived extracellular vesicles miRNAs in anti-PR3 positive vasculitis

In vasculitis disorders, inflammation affects blood vessels. Granulomatosis with polyangiitis (GPA) is a chronic systemic vasculitis distinguished by the presence of anti-proteinase-3 autoantibodies (anti-PR3). In this study we analyzed the molecular signature of human umbilical endothelial cells (HUVECs) in response to neutrophil-derived extracellular vesicles (EVs). EVs were obtained from anti-PR3-activated neutrophils, purified and characterized by flow cytometry, nanoparticle tracking and miRNA screening. HUVECs were stimulated with EVs and miRNA/mRNA expression was measured. Cell culture media proteins were identified by antibody microarrays and selected cytokines were measured. Comparison of differentially expressed miRNAs/mRNAs between non-stimulated and EV-stimulated HUVECs revealed two regulatory patterns. Significant up-regulation of 14 mRNA transcripts (including CXCL8, DKK1, IL1RL1, ANGPT-2, THBS1 and VCAM-1) was accompanied by 11 miRNAs silencing (including miR-661, miR-664a-3p, miR-377-3p, miR-30d-5p). Significant down-regulation was observed for nine mRNA transcripts (including FASLG, CASP8, STAT3, GATA3, IRAK1 and IL6) and accompanied by up-regulation of 10 miRNAs (including miR-223-3p, miR-142-3p, miR-211-5p). Stimulated HUVECs released IL-8, Dickkopf-related protein 1 (DKK-1), soluble interleukin (IL)-1 like receptor-1 (ST2), growth differentiation factor 15 (GDF-15), angiopoietin-2, endoglin, thrombospondin-1 and vascular adhesion molecule-1 (VCAM-1). Moreover, transfection of HUVECs with mimics of highly expressed in EVs miR-223-3p or miR-142-3p, stimulated production of IL-8, ST2 and endoglin. Cytokines released by HUVECs were also elevated in blood of patients with GPA. The most increased were IL-8, DKK-1, ST2, angiopoietin-2 and IL-33. In-vitro stimulation of HUVECs by neutrophil-derived EVs recapitulates contribution of endothelium in autoimmune vasculitis. Proinflammatory phenotype of released cytokines corresponds with the regulatory network of miRNAs/mRNAs comprising both EVs miRNA and endothelial cell transcripts.

Development of the CK-MB-1 trastuzumab-resistant HER2-positive breast cancer cell line and xenograft animal models

Background

Patients with human epidermal growth factor receptor 2 (HER2)‐positive breast cancer who fail to respond to anti‐HER2 treatments have poor prognoses. Most trastuzumab‐resistant breast cancer cell lines available from biobanks feature either phosphoinositide‐3‐kinase, catalytic, alpha (PIK3CA) mutation or the loss of phosphatase and tensin homolog (PTEN). However, PIK3CA mutations and/or PTEN loss do not account for most trastuzumab‐resistant tumors in humans.

Methods

Breast cancer cells were collected from one patient's malignant ascites. These cells were cultured and maintained to develop a stable cell line, which we named CK‐MB‐1. We used western blotting to evaluate protein expression. The PIK3CA status of CK‐MB‐1 cells was analyzed using Sanger sequencing and validated using next‐generation sequencing. In vivo, CK‐MB‐1 xenograft tumor models were developed in zebrafish and immunodeficient mice.

Results

CK‐MB‐1 cells maintained the major characteristics of the parental tumor including HER2 positivity and estrogen receptor negativity. The HER2 gene amplification of CK‐MB‐1 cells was detected by fluorescence in situ hybridization. The integrity of PTEN was confirmed by its positive protein expression and the absence of gene mutations. No common PIK3CA mutation was detected. Compared with the findings in two other HER2‐positive trastuzumab‐resistant cell lines, CK‐MB‐1 cells exhibited greater resistance to trastuzumab, chemotherapeutics, and small‐molecule drugs. Trastuzumab resistance in CK‐MB‐1 cells was confirmed in vivo using the NOD SCID mouse model.

Conclusions

CK‐MB‐1 cells represent a stable HER2‐positive trastuzumab‐resistant breast cancer cell line. The resistance of CK‐MB‐1 cells does not originate from the PTEN or phosphoinositide 3‐kinase signaling pathway, which can provide an alternative approach for potential drugs.

Prebiotic Potential and Anti-Inflammatory Activity of Soluble Polysaccharides Obtained from Soybean Residue

In the present study, we assessed the extraction of low molecular weight soluble polysaccharides (MESP) from soybean by-products using microwave-assisted enzymatic technology and proposed the chemical structure of MESP using Fourier transform-infrared spectroscopy, gas chromatography, and ¹H and ¹³C nuclear magnetic resonance spectrum analysis. The results suggested that MESP mainly comprised arabinose, rhamnose, and glucuronic acid with (1→4) glycosidic linkages in the backbone. Compared with inulin, MESP was found to selectively stimulate the growth of Lactobacillus probiotics. Moreover, the results of in vitro fermentation indicated that MESP significantly increased the concentrations of both acetate and butyrate (p < 0.05). MESP were treated on lipopolysaccharide (LPS)-stimulated RAW264.7 cells to determine the anti-inflammatory effect in vitro. It was observed that MESP inhibited nitric oxide, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-10 production. Furthermore, Western blotting results indicated that MESP significantly attenuated LPS-induced downregulation of phosphorylation levels of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) in macrophages. The underlying mechanism might involve inhibition of the expression of pro-inflammatory cytokines, presumably via JAK2/STAT3 pathway. Collectively, the results of our study paved way for the production of MESP, which may be potentially used as nutraceutical ingredients for prebiotics and anti-inflammatory agents, from soybean residue.

Mechanical pain of the lower extremity after compression of the upper spinal cord involves signal transducer and activator of transcription 3-dependent reactive astrocytes and interleukin-6

Chronic pain is one of the main symptoms of spinal disorders such as spinal canal stenosis. A major cause of this pain is related to compression of the spinal cord, and chronic pain can develop at the level of the compressed spinal segment. However, in many patients chronic pain arises in an area that does not correspond to the compressed segment, and the underlying mechanism involved remains unknown. This was investigated in the present study using a mouse model of spinal cord compression in which mechanical pain of the hindpaws develops after compression of the first lumbar segment (L1) of the spinal cord. Compression induced the activation of astrocytes in the L1 spinal dorsal horn (SDH)-but not the L4 SDH that corresponds to the hindpaws-and activated signal transducer and activator of transcription 3 (STAT3). Suppressing reactive astrocytes by expressing a dominant negative form of STAT3 (dnSTAT3) in the compressed SDH prevented mechanical pain. Expression of interleukin (IL)-6 was also upregulated in the compressed SDH, and it was inhibited by astrocytic expression of dnSTAT3. Intrathecal administration of a neutralizing anti-IL-6 antibody reversed the compression-induced mechanical pain. These results suggest that astrocytic STAT3 and IL-6 in the compressed SDH are involved in remote mechanical pain observed in the lower extremity, and may provide a target for treating chronic pain associated with spinal cord compression such as spinal canal stenosis.

JAK/STAT3 and NF-κB Signaling Pathways Regulate Cancer Stem-Cell Properties in Anaplastic Thyroid Cancer Cells

Background: Anaplastic thyroid carcinoma (ATC) is one of the most aggressive and refractory cancers, and a therapy with a new concept needs to be developed. Recently, research on cancer stem cells (CSCs) has progressed, and CSCs have been suggested to be responsible for metastasis, recurrence, and therapy resistance. In ATC-CSCs, aldehyde dehydrogenase (ALDH) activity is the most reliable marker to enrich CSCs. However, it is just a marker and is not involved in CSC properties. The present study therefore aimed to identify key signaling pathways specific for ATC-CSCs. Methods: A small interfering RNA library targeting 719 kinases was used in a sphere formation assay and cell survival assay using ATC cell lines to select target molecules specific for CSC properties. The functions of the selected candidates were confirmed by sphere formation, cell survival, soft agar, and nude mice xenograft assays using small compound inhibitors. Results: The study focused on PDGFR, JAK, and PIM, whose small interfering RNAs had a higher inhibitory effect on sphere formation, as well as a lower or no effect on regular cell growth in both FRO and KTC3 cells. Next, inhibitors of PDGFR, JAK, STAT3, PIM and NF-κB were used, and all of them successfully suppressed sphere formation in a dose-dependent manner but not regular cell growth, confirming the screening results. Inhibition of the JAK/STAT3 and NF-κB pathways also reduced anchorage-independent growth in soft agar and tumor growth in nude mice. Conclusions: These results suggest that JAK/STAT3 and NF-κB signals play important roles in ATC-CSCs. Targeting these signaling pathways may be a promising approach to treat ATC.

Therapeutic Implication of SOCS1 Modulation in the Treatment of Autoimmunity and Cancer

The suppressor of cytokine signaling (SOCS) family of intracellular proteins has a vital role in the regulation of the immune system and resolution of inflammatory cascades. SOCS1, also called STAT-induced STAT inhibitor (SSI) or JAK-binding protein (JAB), is a member of the SOCS family with actions ranging from immune modulation to cell cycle regulation. Knockout of SOCS1 leads to perinatal lethality in mice and increased vulnerability to cancer, while several SNPs associated with the SOCS1 gene have been implicated in human inflammation-mediated diseases. In this review, we describe the mechanism of action of SOCS1 and its potential therapeutic role in the prevention and treatment of autoimmunity and cancer. We also provide a brief outline of the other JAK inhibitors, both FDA-approved and under investigation.

Long non‑coding RNA DILC is involved in sepsis by modulating the signaling pathway of the interleukin‑6/signal transducer and activator of transcription 3/Toll‑like receptor 4 axis

Sepsis is characterized by systemic inflammatory responses. In the present study, the role of deleted in liver cancer 1 (DILC), interleukin (IL)‑6, signal transducer and activator of transcription 3 (STAT3), and Toll‑like receptor 4 (TLR4) in the pathogenesis of sepsis was investigated. Reverse transcription‑quantitative polymerase chain reaction analysis and western blotting were performed to evaluate the effects of lipopolysaccharide (LPS) on the expression of DILC, IL‑6, STAT3, and TLR4, in addition to the effects of DILC and IL‑6 on the synthesis of tumor necrosis factor (TNF‑α), chemokine ligand 5 (CCL5), E‑selectin and C‑X‑C motif chemokine receptor 1 (CXCR1). In addition, the regulatory association between DILC, IL‑6, STAT3 and TLR4 was investigated. LPS reduced the expression level of DILC, and enhanced the expression of IL‑6, STAT3 and TLR4. DILC directly and negatively regulated the synthesis of IL‑6, as demonstrated by the markedly decreased luciferase activity in cells transfected with a wild‑type DILC plasmid. On the other hand, compared with the scramble control, DILC and IL‑6 small interfering (si)RNAs significantly suppressed the expression of IL‑6, STAT3 and TLR4. In addition, DILC siRNA enhanced the expression of IL‑6, STAT3 and TLR4, whereas the expression levels of TNF‑α, CCL5, E‑selectin and CXCR1 in LPS‑treated THP‑1 cells were downregulated following transfection with DILC and IL‑6 siRNAs. In patients with sepsis, DILC expression was inhibited, although the expression levels of IL‑6, STAT3 and TLR4 were upregulated. In addition, the expression levels of TNF‑α, CCL5, E‑selectin and CXCR1 in patients with sepsis were higher compared with normal subjects. Therefore, DILC may mediate the crosstalk between the cascades of IL‑6/STAT3 and TNF‑α signaling, indicating that DILC may act as a prognostic biomarker of sepsis, and may serve as a potential therapeutic target for the treatment of sepsis.

Overexpressed HO-1 is associated with reduced STAT3 activation in preeclampsia placenta and inhibits STAT3 phosphorylation in placental JEG-3 cells under hypoxia

INTRODUCTION

Inadequate trophoblast invasion and placentation are widely believed to contribute to preeclampsia, and multiple lines of evidence indicate the involvement of hypoxia in preeclampsia. However, the molecular mechanisms underlying the association of placental hypoxia with preeclampsia are not clear.

MATERIAL AND METHODS

The present study focused on the role in preeclampsia of heme oxygenase 1 (HO-1), which is an inducible isoform of HO in response to hypoxia, via examining the expression of HO-1 and the expression and phosphorylation (Tyr705) of Signal transducer and activator of transcription (STAT) 3 in preeclamptic placentas via the immunohistochemical method, western blotting assay and RT-qPCR method. Then we investigated the regulation by HO-1 of the expression and phosphorylation of STAT3 in human placental choriocarcinoma JEG-3 cells under hypoxia.

RESULTS

There was upregulation of HO-1 at both mRNA (1.506 ±0.08347 (N = 37) vs. 1.000 ±0.08854 (N = 31), p < 0.0001) and protein (0.630 ±0.155 (N = 35) vs. 0.310 ±0.052, 0.630 ±0.155 (N = 35), p < 0.001) levels and a reduced level of STAT3 phosphorylation (Tyr 705) in the preeclamptic placental tissues, compared to normal placental tissues (0.143 ±0.027 (N = 35) vs. 0.194 ±0.028 (N = 35), p < 0.01). Also, in vitro experiments demonstrated that HO-1 was markedly promoted by hypoxia in human placental choriocarcinoma JEG-3 cells, 6 or 12 h post treatment (p < 0.05 or p < 0.01). However, the STAT3 phosphorylation (Tyr 705) was attenuated by sustained hypoxia (p < 0.01). Moreover, it was demonstrated that HO-1 overexpression significantly inhibited the hypoxia-promoted STAT3 phosphorylation (Tyr 705).

CONCLUSIONS

HO-1 was overexpressed in PE placenta, in association with reduced STAT3 phosphorylation (Tyr 705). HO-1 inhibits the STAT3 phosphorylation in placental JEG-3 cells under hypoxia. Thus, we speculate that overexpressed HO-1 might contribute to the reduced STAT3 phosphorylation (Tyr 705) and the pathogenesis of preeclampsia.

Image-Based Profiling Can Discriminate the Effects of Inhibitors on Signaling Pathways under Differential Ligand Stimulation

A major advantage of image-based phenotypic profiling of compounds is that numerous image features can be sampled and quantitatively evaluated in an unbiased way. However, since this assay is a discovery-oriented screening, it is difficult to determine the optimal experimental setup in advance. In this study, we examined whether variable cellular stimulation affects the efficacy of the image-based profiling of compounds. Seven different epidermal growth factor receptor (EGFR) ligands were used, and the expression of EGFR signaling molecules was monitored at various time points. Significant quantitative differences in image features were detected among the differentially treated samples. Next, 14 different compounds that affect EGFR signaling were profiled. Nearly half of the compounds were classified into distinct clusters, irrespective of differential ligand stimulation. The results suggest that image-based phenotypic profiling is quite robust in its ability to predict compound interaction with its target. Although this method will have to be validated in other experimental systems, the robustness of image-based compound profiling demonstrated in this work provides a valid basis for further study and its extended application.

Genetic predisposition to lung adenocarcinoma among never-smoking Chinese with different epidermal growth factor receptor mutation status

OBJECTIVES

The inconsistent findings from genetic association studies may be related to the heterogeneity in different molecular subtypes of lung cancer. This study evaluated the predisposing single-nucleotide polymorphisms (SNPs) in epidermal growth factor receptor (EGFR) mutant and EGFR wild-type lung adenocarcinoma separately among never-smokers.

MATERIALS AND METHODS

This was a two-stage case-control study. Never-smokers with pathologically confirmed lung adenocarcinoma and healthy controls were recruited in Hong Kong and Macau. Genomic DNA was extracted and genotyped by MassARRAY. In the discovery stage, 51 SNPs were investigated at the SNP, gene and pathway level among 103 EGFR mutant and 78 EGFR wild-type lung adenocarcinoma cases compared with matched controls. In the validation stage, SNPs that were identified with significant lung cancer risk were replicated in a separate cohort of 84 lung adenocarcinoma cases and compared with 103 Chinese Han, Beijing and 105 Chinese Han, Southern public controls from the 1000 genome database.

RESULTS AND CONCLUSION

The genetic association of IL-6 rs2069840 with EGFR mutant lung adenocarcinoma was ascertained. In the discovery stage, haplotype GGG in three SNPs (rs2069840, rs2069852, rs2066992) of IL-6, synergetic effects of IL-6 rs2069840 and environmental tobacco smoke in the workplace were found to be related to EGFR mutant lung adenocarcinoma. ERCC2 rs238406 showed a marginally significant association with EGFR mutant lung adenocarcinoma in the validation stage (P=0.096). ERCC2 rs50871 and ATM rs611646 showed significant association with EGFR wild-type lung adenocarcinoma in the discovery stage. In conclusion, IL-6 rs2069840 conferred susceptibility to EGFR mutant lung adenocarcinoma in a Hong Kong and Macau never-smoking Chinese population.

Clinical implications of the novel cytokine IL-38 expressed in lung adenocarcinoma: Possible association with PD-L1 expression

Interleukin (IL)-38, a novel member of the IL-1 cytokine family, is homologous to IL-1 receptor antagonist (IL-1Ra) and IL-36Ra, and has been reported to act as an antagonist. IL-38 expression is found in tonsil, placenta, and spleen, and recent studies suggest an association between IL-38 and autoimmune diseases. However, whether IL-38 plays a role in carcinogenesis or cancer growth is unclear. In the present study, we identified increases in IL-38 expression by immunohistochemistry in multiple types of cancer cells. In the examination of 417 surgically resected primary lung adenocarcinomas, Fisher's exact tests showed significant associations between high IL-38 expression and high tumor grades, an advanced T status, advanced N status, advanced stage, and the presence of pleural and vessel invasions. Survival analyses by the Kaplan-Meier method showed that patients with high expression of IL-38 had significantly shorter disease-free survival and shorter overall survival after surgery than patients with low expression of IL-38 (log-rank test: P = 0.0021 and P = 0.0035, respectively). Moreover, programmed cell death-ligand 1 (PD-L1)-positive cases showed higher expression of IL-38 than PD-L1-negative cases (Wilcoxon rank-sum test: P < 0.0001). In conclusion, IL-38 was expressed in tumor cells of various cancers, and IL-38 expression was associated with poor survival of lung adenocarcinoma patients. IL-38 may affect host immunity or the tumor microenvironment, and contribute to the progression of lung adenocarcinoma.

Identification of novel small molecules that inhibit STAT3-dependent transcription and function

Activation of Signal Transducer and Activator of Transcription 3 (STAT3) has been linked to several processes that are critical for oncogenic transformation, cancer progression, cancer cell proliferation, survival, drug resistance and metastasis. Inhibition of STAT3 signaling has shown a striking ability to inhibit cancer cell growth and therefore, STAT3 has become a promising target for anti-cancer drug development. The aim of this study was to identify novel inhibitors of STAT-dependent gene transcription. A cellular reporter-based system for monitoring STAT3 transcriptional activity was developed which was suitable for high-throughput screening (Z’ = 0,8). This system was used to screen a library of 28,000 compounds (the ENAMINE Drug-Like Diversity Set). Following counter-screenings and toxicity studies, we identified four hit compounds that were subjected to detailed biological characterization. Of the four hits, KI16 stood out as the most promising compound, inhibiting STAT3 phosphorylation and transcriptional activity in response to IL6 stimulation. In silico docking studies showed that KI16 had favorable interactions with the STAT3 SH2 domain, however, no inhibitory activity could be observed in the STAT3 fluorescence polarization assay. KI16 inhibited cell viability preferentially in STAT3-dependent cell lines. Taken together, using a targeted, cell-based approach, novel inhibitors of STAT-driven transcriptional activity were discovered which are interesting leads to pursue further for the development of anti-cancer therapeutic agents.

Abnormal repression of SHP-1, SHP-2 and SOCS-1 transcription sustains the activation of the JAK/STAT3 pathway and the progression of the disease in multiple myeloma

Sustained activation of JAK/STAT3 signaling pathway is classically described in Multiple Myeloma (MM). One explanation could be the silencing of the JAK/STAT suppressor genes, through the hypermethylation of SHP-1 and SOCS-1, previously demonstrated in MM cell lines or in whole bone marrow aspirates. The link between such suppressor gene silencing and the degree of bone marrow invasion or the treatment response has not been evaluated in depth. Using real-time RT-PCR, we studied the expression profile of three JAK/STAT suppressor genes: SHP-1, SHP-2 and SOCS-1 in plasma cells freshly isolated from the bone marrows of MM patients and healthy controls. Our data demonstrated an abnormal repression of such genes in malignant plasma cells and revealed a significant correlation between such defects and the sustained activation of the JAK/STAT3 pathway during MM. The repressed expression of SHP-1 and SHP-2 correlated significantly with a high initial degree of bone marrow infiltration but was, unexpectedly, associated with a better response to the induction therapy. Collectively, our data provide new evidences that substantiate the contribution of JAK/STAT suppressor genes in the pathogenesis of MM. They also highlight the possibility that the decreased gene expression of SHP-1 and SHP-2 could be of interest as a new predictive factor of a favorable treatment response, and suggest new potential mechanisms of action of the therapeutic molecules. Whether such defect helps the progression of the disease from monoclonal gammopathy of unknown significance to MM remains, however, to be determined.

Early Secreted Antigenic Target of 6-kDa of Mycobacterium tuberculosis Stimulates IL-6 Production by Macrophages through Activation of STAT3

As early secreted antigenic target of 6 kDa (ESAT-6) of Mycobacterium tuberculosis (Mtb) is an essential virulence factor and macrophages are critical for tuberculosis infection and immunity, we studied ESAT-6 stimulated IL-6 production by macrophages. ESAT-6 stimulated significantly higher IL-6 secretion by murine bone marrow derived macrophages (BMDM) compared to culture filtrate protein 10 kDa (CFP10) and antigen 85A. Polymyxin B, an LPS blocker, did not affect ESAT-6 stimulated macrophage IL-6 production. ESAT-6 but not Pam3CSK4 induced IL-6 by TLR2 knockout BMDM. ESAT-6 induced phosphorylation and DNA binding of STAT3 and this was blocked by STAT3 inhibitors but not by rapamycin. STAT3 inhibitors suppressed ESAT-6-induced IL-6 transcription and secretion without affecting cell viability. This was confirmed by silencing STAT3 in macrophages. Blocking neither IL-6Rα/IL-6 nor IL-10 affected ESAT-6-induced STAT3 activation and IL-6 production. Infection of BMDM and human macrophages with Mtb with esat-6 deletion induced diminished STAT3 activation and reduced IL-6 production compared to wild type and esat-6 complemented Mtb strains. Administration of ESAT-6 but not CFP10 induced STAT3 phosphorylation and IL-6 expression in the mouse lungs, consistent with expression of ESAT-6, IL-6 and phosphorylated-STAT3 in Mtb-infected mouse lungs. We conclude that ESAT-6 stimulates macrophage IL-6 production through STAT3 activation.

Lapatinib increases motility of triple-negative breast cancer cells by decreasing miRNA-7 and inducing Raf-1/MAPK-dependent interleukin-6

Lapatinib, a dual epidermal growth factor receptor (EGFR) and HER2 tyrosine kinase inhibitor (TKI), has been approved for HER2-positive breast cancer patients. Nevertheless, its inhibitory effect on EGFR did not deliver clinical benefits for triple-negative breast cancer (TNBC) patients even EGFR overexpression was frequently found in this disease. Moreover, lapatinib was unexpectedly found to enhance metastasis of TNBC cells, but the underlying mechanisms are not fully understood. In this study, we explored that the level of interleukin-6 (IL-6) was elevated in lapatinib-treated TNBC cells. Treatment with IL-6 antibody abolished the lapatinib-induced migration. Mechanistically, the signaling axis of Raf-1/mitogen-activated protein kinases (MAPKs), c-Jun N-terminal kinases (JNKs), p38 MAPK, and activator protein 1 (AP-1) was activated in response to lapatinib treatment to induce IL-6 expression. Furthermore, our data showed that microRNA-7 directly binds and inhibits Raf-1 3'UTR activity, and that down-regulation of miR-7 by lapatinib contributes to the activation of Raf-1 signaling pathway and the induction of IL-6 expression. Our results not only revealed IL-6 as a key regulator of lapatinib-induced metastasis, but also explored the requirement of miR7/Raf-1/MAPK/AP-1 axis in lapatinib-induced IL-6 expression.

The Exosome - A Naturally Secreted Nanoparticle and its Application to Wound Healing

Wound healing is a complex process and often delayed in patients with underlying chronic conditions. The cost of wound care is a significant burden to the society, warranting new techniques to prompt wound healing. Several studies have reported on the beneficial effects of mesenchymal stem cells (MSCs) function in recruiting host cells, releasing secretory factors and matrix proteins thereby increasing wound heal. These secrete bioactive trophic factors from MSCs also includes extracellular vesicles (EVs) or exosomes. Recent studies have shown that EVs are one of the key secretory products of MSCs mediating cell-to-cell communication to enhance wound healing. Current knowledge related to the potential use of EVs in wound healing is reviewed and the promising future for EVs - a naturally secreted nanoparticle - as an alternative to cell-based therapy is discussed.

Image-based compound profiling reveals a dual inhibitor of tyrosine kinase and microtubule polymerization

Small-molecule compounds are widely used as biological research tools and therapeutic drugs. Therefore, uncovering novel targets of these compounds should provide insights that are valuable in both basic and clinical studies. I developed a method for image-based compound profiling by quantitating the effects of compounds on signal transduction and vesicle trafficking of epidermal growth factor receptor (EGFR). Using six signal transduction molecules and two markers of vesicle trafficking, 570 image features were obtained and subjected to multivariate analysis. Fourteen compounds that affected EGFR or its pathways were classified into four clusters, based on their phenotypic features. Surprisingly, one EGFR inhibitor (CAS 879127-07-8) was classified into the same cluster as nocodazole, a microtubule depolymerizer. In fact, this compound directly depolymerized microtubules. These results indicate that CAS 879127-07-8 could be used as a chemical probe to investigate both the EGFR pathway and microtubule dynamics. The image-based multivariate analysis developed herein has potential as a powerful tool for discovering unexpected drug properties.

MiR-125a promotes paclitaxel sensitivity in cervical cancer through altering STAT3 expression

Cervical cancer (CC) is one of the most common malignancies in women. Paclitaxel is the front-line chemotherapeutic agent for treating CC. However, its therapeutic efficacy is limited because of chemoresistance, the mechanism of which remains poorly understood. Here, we used microRNA (miRNA) arrays to compare miRNA expression levels in the CC cell lines, HeLa and CaSki, with their paclitaxel resistance counterparts, HeLa/PR and CaSki/PR. We demonstrate that miR-125a was one of most significantly downregulated miRNAs in paclitaxel-resistant cells, which also acquired cisplatin resistance. And that the upregulation of miR-125a sensitized HeLa/PR and CaSki/PR cells to paclitaxel both in vitro and in vivo and to cisplatin in vitro. Moreover, we determined that miR-125a increased paclitaxel and cisplatin sensitivity by downregulating STAT3. MiR-125a enhanced paclitaxel and cisplatin sensitivity by promoting chemotherapy-induced apoptosis. Clinically, miR-125a expression was associated with an increased responsiveness to paclitaxel combined with cisplatin and a more favorable outcome. These data indicate that miR-125a may be a useful method to enable treatment of chemoresistant CC and may also provide a biomarker for predicting paclitaxel and cisplatin responsiveness in CC.

Sip-jeon-dea-bo-tang, a traditional herbal medicine, ameliorates cisplatin-induced anorexia via the activation of JAK1/STAT3-mediated leptin and IL-6 production in the fat tissue of mice

Despite its therapeutic advantages, chemotherapy can also cause adverse effects, including anorexia and loss of appetite. Although numerous patients with cancer have been reported to suffer from anorexia during or following chemotherapy, treatment options for anorexia remain to be determined. In Asian countries, traditional medicines are widely used to treat problems with appetite; sip-jeon-dea-bo-tang (SJDBT) is one of those medicines used for the treatment of anorexia. The present study demonstrated that SJDBT ameliorated cisplatin-induced anorexia. In a mouse model of chemotherapy-induced anorexia, oral administration of SJDBT prevented the cisplatin-induced reduction of food intake, inhibiting weight loss. The results of multiplex assays showed that SJDBT only altered the levels of interleukin (IL)-6 and leptin in the serum and fat tissue. In addition, SJDBT maintained the serum leptin level and increased the serum IL-6 level, whereas cisplatin reduced the levels of both serum leptin and IL-6. Furthermore, SJDBT was revealed to increase the levels of leptin and IL-6 in the fat tissue by activating the JAK1/STAT3 signaling pathway. In conclusion, the present results revealed that SJDBT ameliorated cisplatin-induced anorexia, suggesting its usefulness in the prevention of anorexia during chemotherapy.

Mesenchymal Stem Cell Exosomes Induce Proliferation and Migration of Normal and Chronic Wound Fibroblasts, and Enhance Angiogenesis In Vitro

Although chronic wounds are common and continue to be a major cause of morbidity and mortality, treatments for these conditions are lacking and often ineffective. A large body of evidence exists demonstrating the therapeutic potential of mesenchymal stem cells (MSCs) for repair and regeneration of damaged tissue, including acceleration of cutaneous wound healing. However, the exact mechanisms of wound healing mediated by MSCs are unclear. In this study, we examined the role of MSC exosomes in wound healing. We found that MSC exosomes ranged from 30 to 100-nm in diameter and internalization of MSC exosomes resulted in a dose-dependent enhancement of proliferation and migration of fibroblasts derived from normal donors and chronic wound patients. Uptake of MSC exosomes by human umbilical vein endothelial cells also resulted in dose-dependent increases of tube formation by endothelial cells. MSC exosomes were found to activate several signaling pathways important in wound healing (Akt, ERK, and STAT3) and induce the expression of a number of growth factors [hepatocyte growth factor (HGF), insulin-like growth factor-1 (IGF1), nerve growth factor (NGF), and stromal-derived growth factor-1 (SDF1)]. These findings represent a promising opportunity to gain insight into how MSCs may mediate wound healing.

JAK2/STAT3 inhibition attenuates noise-induced hearing loss

Signal transducers and activators of transcription 3 (STAT3) is a stress responsive transcription factor that plays a key role in oxidative stress-mediated tissue injury. As reactive oxygen species (ROS) are a known source of damage to tissues of the inner ear following loud sound exposure, we examined the role of the Janus kinase 2 (JAK2)/STAT3 signaling pathway in noise induce hearing loss using the pathway specific inhibitor, JSI-124. Mice were exposed to a moderately damaging level of loud sound revealing the phosphorylation of STAT3 tyrosine 705 residues and nuclear localization in many cell types in the inner ear including the marginal cells of the stria vascularis, type II, III, and IV fibrocytes, spiral ganglion cells, and in the inner hair cells. Treatment of the mice with the JAK2/STAT3 inhibitor before noise exposure reduced levels of phosphorylated STAT3 Y705. We performed auditory brain stem response and distortion product otoacoustic emission measurements and found increased recovery of hearing sensitivity at two weeks after noise exposure with JAK2/STAT3 inhibition. Performance of cytocochleograms revealed improved outer hair cell survival in JSI-124 treated mice relative to control. Finally, JAK2/STAT3 inhibition reduced levels of ROS detected in outer hair cells at two hours post noise exposure. Together, these findings demonstrate that inhibiting the JAK2/STAT3 signaling pathway is protective against noise-induced cochlear tissue damage and loss of hearing sensitivity.

Dendritic cell-mediated survival signals in Eμ-Myc B-cell lymphoma depend on the transcription factor C/EBPβ

The capacity of dendritic cells (DCs) to regulate tumour-specific adaptive immune responses depends on their proper differentiation and homing status. Whereas DC-associated tumour-promoting functions are linked to T-cell tolerance and formation of an inflammatory milieu, DC-mediated direct effects on tumour growth have remained unexplored. Here we show that deletion of DCs substantially delays progression of Myc-driven lymphomas. Lymphoma-exposed DCs upregulate immunomodulatory cytokines, growth factors and the CCAAT/enhancer-binding protein β (C/EBPβ). Moreover, Eμ-Myc lymphomas induce the preferential translation of the LAP/LAP* isoforms of C/EBPβ. C/EBPβ(-/-) DCs are unresponsive to lymphoma-associated cytokine changes and in contrast to wild-type DCs, they are unable to mediate enhanced Eμ-Myc lymphoma cell survival. Antigen-specific T-cell proliferation in lymphoma-bearing mice is impaired; however, this immune suppression is reverted by the DC-restricted deletion of C/EBPβ. Thus, we show that C/EBPβ-controlled DC functions are critical steps for the creation of a lymphoma growth-promoting and -immunosuppressive niche.

Phosphatase of regenerating liver-3 is regulated by signal transducer and activator of transcription 3 in acute myeloid leukemia

Overexpression of protein-tyrosine phosphatase of regenerating liver 3 (PRL-3) has been identified in about 50% of patients with acute myeloid leukemia (AML). The mechanism of regulation of PRL-3 remains obscure. Signal transducer and activator of transcription 3 (STAT3), a latent transcriptional factor, has also been often found to be activated in AML. We first identified STAT3-consensus-binding sites in the promoter of PRL-3 genes. Then we experimentally validated the direct binding and transcriptional activation. We applied shRNA-mediated knockdown and overexpression approaches in STAT3(-/-) liver cells and leukemic cells to validate the functional regulation of PRL-3 by STAT3. A STAT3 core signature, derived through data mining from publicly available gene expression data, was employed to correlate PRL-3 expression in large AML patient samples. We discovered that STAT3 binds to the -201 to -210 region of PRL-3, which was conserved between human and mouse. Importantly, PRL-3 protein was significantly reduced in mouse STAT3-knockout liver cells compared with STAT3-wild type counterparts, and ectopic expression of STAT3 in these cells led to a pronounced increase in PRL-3 protein. We demonstrated that STAT3 functionally regulated PRL-3, and STAT3 core signature was enriched in AML with high PRL-3 expression. Targeting either STAT3 or PRL-3 reduced leukemic cell viability. Silencing PRL-3 impaired invasiveness and induced leukemic cell differentiation. In conclusion, PRL-3 was transcriptionally regulated by STAT3. The STAT3/PRL-3 regulatory loop contributes to the pathogenesis of AML, and it might represent an attractive therapeutic target for antileukemic therapy.

Autophagy promotes radiation-induced senescence but inhibits bystander effects in human breast cancer cells

Ionizing radiation induces cellular senescence to suppress cancer cell proliferation. However, it also induces deleterious bystander effects in the unirradiated neighboring cells through the release of senescence-associated secretory phenotypes (SASPs) that promote tumor progression. Although autophagy has been reported to promote senescence, its role is still unclear. We previously showed that radiation induces senescence in PTTG1-depleted cancer cells. In this study, we found that autophagy was required for the radiation-induced senescence in PTTG1-depleted breast cancer cells. Inhibition of autophagy caused the cells to switch from radiation-induced senescence to apoptosis. Senescent cancer cells exerted bystander effects by promoting the invasion and migration of unirradiated cells through the release of CSF2 and the subsequently activation of the JAK2-STAT3 and AKT pathways. However, the radiation-induced bystander effects were correlated with the inhibition of endogenous autophagy in bystander cells, which also resulted from the activation of the CSF2-JAK2 pathway. The induction of autophagy by rapamycin reduced the radiation-induced bystander effects. This study reveals, for the first time, the dual role of autophagy in radiation-induced senescence and bystander effects.

IL-6 and related cytokines as the critical lynchpins between inflammation and cancer

Inflammatory responses play pivotal roles in cancer development, including tumor initiation, promotion, progression, and metastasis. Cytokines are now recognized as important mediators linking inflammation and cancer, and are therefore potential therapeutic and preventive targets as well as prognostic factors. The interleukin (IL)-6 family of cytokines, especially IL-6 and IL-11, is highly up-regulated in many cancers and considered as one of the most important cytokine families during tumorigenesis and metastasis. This review discusses molecular mechanisms linking the IL-6 cytokine family to solid malignancies and their treatment.

SOCS1 hypermethylation mediated by DNMT1 is associated with lipopolysaccharide-induced inflammatory cytokines in macrophages

Macrophages activation which releases the pro-inflammatory cytokines is an essential event in the process of inflammation. SOCS1 has been shown to act as a negative regulator of cytokine signals and plays a key role in the suppression of tissue injury and inflammatory diseases. DNA methylation mediated by specific DNA methyltransferases1 (DNMT1) which contributes to the epigenetic silencing of multiple genes. SOCS1 promoter hypermethylation is by far the best categorized epigenetic change in tumors. Our study with a view to investigate whether the loss of SOCS1 due to SOCS1 promoter methylation was involved in the course of inflammatory cytokines released from lipopolysaccharide (LPS)-stimulated macrophages. Here, we found that treatment of LPS-induced RAW264.7 macrophage cells with the DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-azadC) reduced aberrant promoter hypermethylation of SOCS1 and prevented the loss of the expression of SOCS1 in macrophages which secret inflammatory cytokines. Knockdown of DNMT1 gene not only attenuated the SOCS1 gene promoter methylation but also up-regulated the expression of SOCS1 in activated RAW264.7 cells. Furthermore, silencing of DNMT1 prevented the activation of JAK2/STAT3 pathway in LPS-induced RAW264.7 cells. These studies demonstrated that DNMT1-mediated SOCS1 hypermethylation caused the loss of SOCS1 expression results in negative regulation of activation of the JAK2/STAT3 pathway, and enhanced the release of LPS-induced pro-inflammatory cytokines such as TNF-α and IL-6 in macrophages.

Radiation-induced senescence in securin-deficient cancer cells promotes cell invasion involving the IL-6/STAT3 and PDGF-BB/PDGFR pathways

Securin overexpression correlates with poor prognosis in various tumours. We have previously shown that securin depletion promotes radiation-induced senescence and enhances radiosensitivity in human cancer cells. However, the underlying molecular mechanisms and the paracrine effects remain unknown. In this study, we showed that radiation induced senescence in securin-deficient human breast cancer cells involving the ATM/Chk2 and p38 pathways. Conditioned medium (CM) from senescent cells promoted the invasion and migration of non-irradiated cancer and endothelial cells. Cytokine assay analysis showed the up-regulation of various senescence-associated secretory phenotypes (SASPs). The IL-6/STAT3 signalling loop and platelet-derived growth factor-BB (PDGF-BB)/PDGF receptor (PDGFR) pathway were important for CM-induced cell migration and invasion. Furthermore, CM promoted angiogenesis in the chicken chorioallantoic membrane though the induction of IL-6/STAT3- and PDGF-BB/PDGFR-dependent endothelial cell invasion. Taken together, our results provide the molecular mechanisms for radiation-induced senescence in securin-deficient human breast cancer cells and for the SASP responses.

Human metapneumovirus inhibits the IL-6-induced JAK/STAT3 signalling cascade in airway epithelium

The host cytokine IL-6 plays an important role in host defence and prevention of lung injury from various pathogens, making IL-6 an important mediator in the host's susceptibility to respiratory infections. The cellular response to IL-6 is mediated through a Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) signal transduction pathway. Human metapneumovirus (hMPV) is an important causative agent of viral respiratory infections known to inhibit the IFN-mediated activation of STAT1. However, little is known about the interactions between this virus and other STAT signalling cascades. Herein, we showed that hMPV can attenuate the IL-6-mediated JAK/STAT3 signalling cascade in lung epithelial cells. HMPV inhibited a key event in this pathway by impeding the phosphorylation and nuclear translocation of STAT3 in A549 cells and in primary normal human bronchial epithelial cells. Further studies established that hMPV interrupted the IL-6-induced JAK/STAT pathway early in the signal transduction pathway by blocking the phosphorylation of JAK2. By antagonizing the IL-6-mediated JAK/STAT3 pathway, hMPV perturbed the expression of IL-6-inducible genes important for apoptosis, cell differentiation and growth. Infection with hMPV also differentially regulated the effects of IL-6 on apoptosis. Thus, hMPV regulation of these genes could usurp the protective roles of IL-6, and these data provide insight into an important element of viral pathogenesis.