Activation Of Janus Kinase Research Articles

Enhanced therapeutic effects of human mesenchymal stem cells transduced with superoxide dismutase 3 in a murine atopic dermatitis-like skin inflammation model.

The use of mesenchymal stem cells (MSCs) has been proposed to treat various autoimmune diseases. However, effective strategies for treating atopic dermatitis (AD) are still lacking, and the mechanisms underlying stem cell therapy remain largely unknown. In this study, we sought to explore potential clinical application of superoxide dismutase 3-transduced MSCs (SOD3-MSCs) to experimental AD-like skin inflammation in invitro and invivo and its underlying anti-inflammatory mechanisms. SOD3-MSCs were administered subcutaneously to mice with AD, and associated symptoms and biologic changes were evaluated. Human keratinocytes, mast cells, and murine T helper (Th) 2 cells were cocultured invitro with SOD3-MSCs to investigate potential therapeutic effects of SOD3-MSCs. In mice with AD, SOD3-MSCs ameliorated AD pathology and enhanced the efficacy of MSC therapy by controlling activated immune cells, by reducing expression levels of proinflammatory mediators in the skin, and by inhibiting the histamine H4 receptor (H4R)-mediated inflammatory cascade and activation of Janus kinase signal transducer and activator of transcription pathways. Similarly, coculture of SOD3-MSCs with mast cells, keratinocytes, and Th2 cells effectively dampened H4R-dependent persistent inflammatory responses by multiple mechanisms. Moreover, we also showed that SOD3 interacts with H4R and IL-4 receptor α. The functional significance of this interaction could be a markedly reduced inflammatory response in keratinocytes and overall AD pathogenesis, representing a novel mechanism for SOD3's anti-inflammatory effects. SOD3-MSCs can be potentially used as an effective and clinically relevant therapy for AD and other autoimmune disorders.

Salvianolic acid B as an anti-emphysema agent I: In vitro stimulation of lung cell proliferation and migration, and protection against lung cell death, and in vivo lung STAT3 activation and VEGF elevation

Emphysema causes progressive and life-threatening alveolar structural destruction/loss, yet remains irreversible and incurable to date. Impaired vascular endothelial growth factor (VEGF) signaling has been proposed as a new pathogenic mechanism, and if so, VEGF recovery may enable reversal of emphysema. Thus, we hypothesized that salvianolic acid B (Sal-B), a polyphenol in traditional Chinese herbal danshen, is an alveolar structural recovery agent for emphysema by virtue of VEGF stimulation/elevation via activation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), as stimulating lung cell proliferation and migration, and protecting against lung cell death. Using in vitro human lung microvascular endothelial (HMVEC-L) and alveolar epithelial (A549) cell systems, Sal-B was examined for 1) stimulation of cell proliferation by the MTT and BrdU assays; 2) promotion of cell migration by the scratch wound closure assay; 3) protection against emphysema-like induced cell death by the trypan blue exclusion and flow cytometry assays; and 4) mechanistic involvement of JAK2/STAT3/VEGF in these activities. Sal-B was also spray-dosed to the lungs of healthy rats for two weeks to verify the lung's STAT3 activation and VEGF elevation by western blot, as well as the absence of functional and morphological abnormalities. All the in vitro cell-based activities were concentration-dependent. At 25 μM, Sal-B 1) stimulated cell proliferation by 1.4–2.6-fold; 2) promoted migratory cell wound closure by 1.5–1.7-fold; and 3) protected against cell death induced with H2O2 (oxidative stress) and SU5416 (VEGF receptor blockade) by 49–86%. JAK2 and STAT3 inhibitors and VEGF receptor antagonist each opposed these Sal-B's activities by over 65%, suggesting the mechanistic involvement of JAK2/STAT3 activation and VEGF stimulation/elevation. In rats, Sal-B at 0.2 mg/kg enabled 1.9 and 1.5-fold increased STAT3 phosphorylation and VEGF elevation in the lungs, respectively, while causing no functional and morphological abnormalities. Hence, Sal-B was projected to be a new class of anti-emphysema agent capable of reversing alveolar structural destruction/loss via JAK2/STAT3/VEGF-dependent stimulation of lung cell proliferation and migration, and inhibition of induced lung cell death.

Efficacy of JAK1/2 inhibition in the treatment of chilblain lupus due to TREX1 deficiency

The type I interferonopathies, Mendelian disorders characterised by constitutive upregulation of the type I interferon (IFN) pathway, are associated with a spectrum of phenotypes particularly involving the brain and the...

Dexmedetomidine protects liver cell line L-02 from oxygen-glucose deprivation-induced injury by down-regulation of microRNA-711.

In liver transplantation, long-time portal vein blocking causes the occurrence of ischemic liver injury. Dexmedetomidine, a widely admired anesthetic, has been reported as a protective agent on organs under ischemic condition. The objective of this study was to reveal the role and underlying mechanism of dexmedetomidine in ischemic liver injury. L-02 cells were treated with dexmedetomidine during 6 h of oxygen-glucose deprivation (OGD) exposure. The expression of microRNA-711 (miR-711) in cell was overexpressed by miRNA transfection. Then, the following parameters were observed: cell viability, apoptosis, the expression of apoptosis-related proteins, and the expression and the release of Interleukin 1 beta (IL-1β) and Tumor necrosis factor alpha (TNF-α). Apoptosis and inflammation were induced following OGD exposure in L-02 cells, as cell viability was impaired, apoptotic cell rate was increased, caspase-3, and caspase-9 was cleaved, and the expression and release of TNF-α and IL-1β were increased. Dexmedetomidine attenuated OGD-induced apoptosis and inflammation, and dexmedetomidine down-regulated the expression of miR-711. Also, dexmedetomidine blocked the activation of p38 mitogen-activated protein kinase (p38MAPK) and Janus kinase (JAK)/signal transducer and activator of transcription protein (STAT) signaling upon OGD. Moreover, when miR-711 was overexpressed, dexmedetomidine did not protect L-02 cells against OGD, and did not block p38MAPK and JAK/STAT signaling pathways. Dexmedetomidine ameliorated OGD-induced cell apoptosis and inflammation in L-02 cells, exerting protective activities in ischemic liver injury. The anti-OGD effects of dexmedetomidine might be realized by down-regulation of miR-711 and suppression of p38MAPK and JAK/STAT signaling pathways.

Janus kinase JAK1 maintains the ovarian reserve of primordial follicles in the mouse ovary

Is the Janus kinase and signal transducer and activator of transcription (JAK-STAT) signalling pathway involved in ovarian follicle development and primordial follicle activation? JAK1 is a key factor involved in the regulation of primordial follicle activation and maintenance of the ovarian reserve. A series of integrated, intrinsic signalling pathways (including PI3K/AKT, mTOR and KITL) are responsible for regulating the ovarian reserve of non-growing primordial follicles and ultimately female fertility. The JAK-STAT signal transduction pathway is highly conserved with established roles in cell division and differentiation. Key pathway members (specifically JAK1, STAT3 and SOCS4) have been previously implicated in early follicle development. A laboratory animal study was undertaken using the C57Bl/6 inbred mouse strain as a model for human ovarian follicle development. To determine which Jak genes were most abundantly expressed during primordial follicle activation, mRNA expression was analysed across a developmental time-course, with ovaries collected from female mice at post-natal days 1 (PND1), 4 (PND4), 8 (PND8), as well as at 6 weeks (6WK) and 7 months (7MTH) (n ≥ 4). Functional analysis of JAK1 was performed on PND2 mouse ovaries subjected to in vitro explant culture treated with 12.5 μM Ruxolitinib (JAK inhibitor) or vehicle control (DMSO) for 48 h prior to histological assessment (n ≥ 4). The expression and localization of the JAK family during ovarian follicle development in the C57Bl/6 inbred mouse strain were evaluated using quantitative PCR, immunoblotting and immunolocalisation. Functional studies were undertaken using the JAK inhibitor Ruxolitinib to investigate the underpinning cellular mechanisms via biochemical in vitro inhibition and histological assessment of intact neonate ovaries. All experiments were replicated at least three times using tissue from different mice unless otherwise stated. Jak1 is the predominant Jak mRNA expressed in the C57Bl/6 mouse ovary across all developmental time-points assessed (P ≤ 0.05). Forty-eight hour inhibition of JAK1 with Ruxolitinib of PND2 ovaries in vitro demonstrated concomitant acceleration of primordial follicle activation and apoptosis (P ≤ 0.001) and upregulation of downstream JAK-STAT pathway members STAT3 and suppressors of cytokine signalling 4 (SOCS4). N/A. Results are shown in one species, the C57Bl/6 mouse strain as an established model of human ovary development. Ruxolitinib also inhibits JAK2, with decreased efficacy. However, Jak2 mRNA had limited expression in the mouse ovary, particularly at the neonatal stages of follicle development, thus any effect of Ruxolitinib on primordial follicle activation was unlikely to be mediated via this isoform. This study supports a key role for JAK1 in the maintenance and activation of primordial follicles, with potential for targeting the JAK-STAT pathway as a method of regulating the ovarian reserve and female fertility. This project has been funded by the Australian National Health and Medical Research Council (G1600095) and The Hunter Medical Research Institute Bob and Terry Kennedy Children's Research Project Grant in Pregnancy & Reproduction (G1501433). All authors declare no conflict of interests.

Targeted regulationof STAT3 by miR-29a in mediating Taxol resistance of nasopharyngeal carcinoma cell line CNE-1.

STAT3 is an important molecule in Janus kinase (JAK) signal transducer and activator of transcription (STAT) signal pathway, and facilitates expression of various oncogenic genes such as Bcl-2, thus is correlated with tumor onset, progression and drug resistance. MiR-29a down-regulation is associated with the pathogenesis of nasopharyngeal carcinoma. Bioinformatics analysis demonstrated a complementary binding between miR-29a and 3'-UTR of STAT3. This study aims to investigate the role of miR-29a in regulating STAT3, as well as in Taxol resistance of nasopharyngeal carcinoma CNE-1 cells. Dual luciferase reporter gene assay showed a regulatory relationship between miR-29a and STAT3. Rhodamine 123 repository in CNE-1 and CNE1/Taxol drug resistant cells was measured together with the expression of miR-29a, STAT3, and p-STAT3. Flow cytometry was used to measure cell apoptosis and PCNA expression under Taxol treatment. CNE-1/Taxol cells were treated with miR-29a mimic and or si-STAT3, followed by measuring the expression of miR-29a, STAT3, and p-STAT3 and cell apoptosis. CCK-8 assay was performed to evaluate cell proliferation. MiR-29a inhibited STAT3 expression. Significantly lower Rhodamine 123 repository, miR-29a expression and apoptosis and higher expression of STAT3, p-STAT3 and PCNA were observed in CNE-2/ Taxol cells than those in CNE-1 cells. Transfection of miR-29a mimic and/or si-STAT3 decreased STAT3, p-STAT3 and PCNA expression, inhibited proliferation and promoted cell apoptosis. MiR-29a down-regulation is correlated with drug resistance of nasopharyngeal carcinoma cell line CNE-1 and MiR-29a up-regulation decreases Taxol resistance of nasopharyngeal carcinoma CNE-1 cells possibly via inhibiting STAT3 and Bcl-2 expression.

Arctiin is a pharmacological inhibitor of STAT3 phosphorylation at tyrosine 705 residue and potentiates bortezomib-induced apoptotic and anti-angiogenic effects in human multiple myeloma cells

BackgroundArctiin is a main component from the fruits of Arctium lappa L., that can be prescribed for cold or flu in East Asian countries; it has also been found to exert chemopreventive actions against various tumor cells. HypothesisIn view of this evidence, we examined arctiin for its ability to trigger apoptosis and inhibit the activation of signal transducer and activator of transcription 3 (STAT3) in human multiple myeloma (MM) cells. MethodsWe evaluated the effect of arctiin on STAT3 signaling cascades and its regulated functional responses in MM cells. ResultsArctiin effectively blocked the constitutive activation of STAT3 phosphorylation in the residue of tyrosine 705. Arctiin also abrogated the constitutive activation of Src phosphorylation and Janus-activated kinases (JAKs) 1/2. Furthermore, it was found that arctiin treatment clearly enhanced the mRNA and protein levels of protein tyrosine phosphatase ε (PTPε), and the silencing of PTPε caused a reversal of the arctiin-induced PTPε expression and the blockadge of STAT3 phosphorylation. Interestingly, arctiin could not repress IL-6-induced STAT3 activation in serum-starved U266 cells and when arctiin was incubated with a complete culture medium in RPMI 8226 and MM.1S cells. Arctiin suppressed cell proliferation, accumulated cells in the G2/M cell-cycle phase, and induced apoptosis within U266 cells, although the knockdown of PTPε prevented PARP cleavage and caspase-3 activation induced by the arctiin. In addition, arctiin exerted cytotoxicity in MM cells, but did not do so in peripheral blood mononuclear cells. Arctiin down-modulated diverse oncogenic gene products regulated by STAT3, although the induction of apoptosis by arctiin was abrogated upon transfection with pMXs-STAT3C in mouse embryonic fibroblast (MEF) cells. Arctiin also potentiated bortezomib-induced antitumor effects in U266 cells. ConclusionOn the whole, our results indicate that arctiin is a potentially new inhibitor of constitutive STAT3 activation through the induction of PTPε in MM, cells and therefore has great value in treating various tumors sheltering constitutively activated STAT3.

Oncostatin M-induced blood-brain barrier impairment is due to prolonged activation of STAT3 signaling in vitro.

Oncostatin M (OSM) is a member of the interleukin (IL)-6 family cytokines. We previously demonstrated that OSM induces blood-brain barrier (BBB) impairment. However, functional characterization of IL-6 family cytokines in BBB regulation and the cytokine-related intracellular signaling pathway remain unclear. In this study, we demonstrate that among IL-6 family cytokines, including IL-6 and leukemia inhibitory factor (LIF), OSM is the most potent molecule for inducing BBB dysfunction via prolonged activation of signal transducer and activator of transcription (STAT) 3 following Janus-activated kinase (JAK) activation. OSM but not IL-6 and LIF (100 ng/mL for 24 hours) markedly produced increased sodium fluorescein permeability and decreased transendothelial electrical resistance in rat brain endothelial cell (RBEC) monolayers. This OSM-induced BBB dysfunction was accompanied by decreased levels of claudin-5 expression in RBECs, which were ameliorated by JAK inhibitor. We examined the time-course of STAT3 phosphorylation in RBECs treated with OSM, IL-6, and LIF. OSM upregulated STAT3 phosphorylation levels during a 24 hours period with a peak at 10 minutes. While IL-6 and LIF transiently increased phosphorylated STAT3 at 10 minutes after addition, this phosphorylation decreased during the period from 1 to 24 hours after addition. These findings suggest that OSM-induced sustained increases in STAT3 phosphorylation levels largely contribute to BBB impairment. Thus, elevated OSM levels and activation of brain endothelial JAK/STAT3 signaling pathway under pathological conditions should be considered as a possible hallmark for induction and development of BBB impairment.

PDGF‑BB promotes the differentiation and proliferation of MC3T3‑E1 cells through the Src/JAK2 signaling pathway.

Platelet-derived growth factor-BB (PDGF-BB) serves a critical function in human osteoblast differentiation and proliferation. Src and Janus kinase 2 (JAK2) are involved in these processes. In our previous study, it was identified that Src could promote the phosphorylation of JAK2. However, it has yet to be determined whether the Src/JAK2 signaling pathway affects PDGF-BB-mediated osteoblast differentiation and proliferation. In the present study, western blotting, polymerase chain reaction, alizarin red staining, alkaline phosphatase and Cell Counting kit-8 were employed to explore these questions. Firstly, it was demonstrated that PDGF-BB activates the Src/JAK2 signaling pathway in MC3T3-E1 cells in a time-dependent manner. Furthermore, it was demonstrated that PDGF-BB expression promoted MC3T3-E1 cell differentiation and proliferation; this process was suppressed by AG1295, SU6656 and AG490, which are inhibitors of PDGFR-β, Src and JAK2, respectively. SU6656 downregulated the activity of Src and JAK2, while AG490 only downregulated JAK2 activity. Therefore, it was concluded that Src is upstream of JAK2. PDGF-BB also upregulated the expression of osteogenesis-associated genes, and the formation of mineral nodules. However, these effects were markedly inhibited by treatment with SU6656. This indicated that PDGF-BB promoted MC3T3-E1 cell differentiation and proliferation by activating the Src/JAK2 signaling pathway. These results suggested that PDGF-BB may have potential applications in the treatment of osteoporosis and bone fractures.

Phase 1 dose-escalation study of momelotinib, a Janus kinase 1/2 inhibitor, combined with gemcitabine and nab-paclitaxel in patients with previously untreated metastatic pancreatic ductal adenocarcinoma

SummaryPurpose Preclinical evidence suggests the importance of Janus activating kinase (JAK) and TANK-binding kinase 1 (TBK1) in pancreatic ductal adenocarcinoma (PDAC). We evaluated the safety and efficacy of momelotinib (MMB), a JAK1/2 inhibitor with additional activity against TBK1, plus albumin-bound paclitaxel + gemcitabine (nab-P + G), in patients with previously untreated metastatic PDAC. Experimental Design Patients were enrolled into five cohorts of increasing doses of MMB between 100 and 200 mg administered once or twice daily in combination with nab-P + G in 28-day cycles to determine maximum tolerated dose (MTD). Safety, efficacy, pharmacokinetics, and pharmacodynamics were assessed for all patients. Results Twenty-five patients were enrolled. Dose-limiting toxicities of Grade 3 diarrhea occurred in 1 patient each in the 100 and 200 mg MMB once-daily dose groups. MTD was not reached. The 200 mg MMB twice-daily was the maximum administered dose. Objective response rate was 28% (all partial responses), and 13 (52%) patients had a best response of stable disease. The most common adverse events (AEs) were fatigue (80%), nausea (76%), and anemia (68%). Grade 3 or 4 AEs, most commonly neutropenia (32%), were reported by 88% of patients, of which 44% were considered related to MMB. Pharmacokinetic analyses showed MMB concentrations were too low for TBK1 inhibition. Conclusions MMB was safe and well tolerated in combination with nab-P + G. As no OS or PFS benefit vs nab-P + G was apparent in context of suboptimal engagement of the target TBK1, this study does not support further development of MMB as a first-line therapy in pancreatic cancer.

Receptor-mediated dimerization of JAK2 FERM domains is required for JAK2 activation.

Cytokines and interferons initiate intracellular signaling via receptor dimerization and activation of Janus kinases (JAKs). How JAKs structurally respond to changes in receptor conformation induced by ligand binding is not known. Here, we present two crystal structures of the human JAK2 FERM and SH2 domains bound to Leptin receptor (LEPR) and Erythropoietin receptor (EPOR), which identify a novel dimeric conformation for JAK2. This 2:2 JAK2/receptor dimer, observed in both structures, identifies a previously uncharacterized receptor interaction essential to dimer formation that is mediated by a membrane-proximal peptide motif called the 'switch' region. Mutation of the receptor switch region disrupts STAT phosphorylation but does not affect JAK2 binding, indicating that receptor-mediated formation of the JAK2 FERM dimer is required for kinase activation. These data uncover the structural and molecular basis for how a cytokine-bound active receptor dimer brings together two JAK2 molecules to stimulate JAK2 kinase activity.

Interferon Lambda: Toward a Dual Role in Cancer.

Interferon (IFN)-λ, a type III interferon (IFN), is a member of a new family of pleotropic cytokines that share high similarity with classical IFNs α and β (IFN-α/β), type I IFNs. IFN-λ acts as an antiviral agent and displays distinct biological functions, including tumor suppression. Although it activates the common Janus kinase (JAK) and signal transducer and activator of transcription (STAT) pathways, similar to IFN-α/β, IFN-λ differentially induces the expression of IFN-stimulated genes (ISGs). Novel evidence indicates that IFN-λ acts quite differently from IFN-α/β under both homeostasis and pathological situations. In contrast to IFN-α/β, IFN-λ is not involved in over-stimulation of the immune response or exacerbation of inflammation. However, the emergence of unexpected characteristics of IFN-λ, in the control of inflammation and promotion of immune suppression and cancer, reveals novel challenges and offers more strategic opportunities in the context of cancer and beyond. In this article, we discuss new evidence and potential consequences associated with the biology of IFN-λ and provide a different vision for building novel therapeutic strategies in oncology.

A genome-wide RNAi screen identifies MASK as a positive regulator of cytokine receptor stability.

Cytokine receptors often act via the Janus kinase and signal transducer and activator of transcription (JAK/STAT) pathway to form a signalling cascade that is essential for processes such as haematopoiesis, immune responses and tissue homeostasis. In order to transduce ligand activation, cytokine receptors must dimerise. However, mechanisms regulating their dimerisation are poorly understood. In order to better understand the processes regulating cytokine receptor levels, and their activity and dimerisation, we analysed the highly conserved JAK/STAT pathway in Drosophila, which acts via a single receptor, known as Domeless. We performed a genome-wide RNAi screen in Drosophila cells, identifying MASK as a positive regulator of Domeless dimerisation and protein levels. We show that MASK is able to regulate receptor levels and JAK/STAT signalling both in vitro and in vivo We also show that its human homologue, ANKHD1, is also able to regulate JAK/STAT signalling and the levels of a subset of pathway receptors in human cells. Taken together, our results identify MASK as a novel regulator of cytokine receptor levels, and suggest functional conservation, which may have implications for human health.This article has an associated First Person interview with the first author of the paper.

Role of janus kinase inhibitors in the treatment of alopecia areata.

Alopecia areata (AA) is a common hair loss disorder worldwide with characteristic exclamation mark hairs. Although AA is self-limited, it can last for several months or even years in some patients. Currently, there is no US Food and Drug Administration-approved treatment for AA. Many off-label treatments are available but with limited efficacy. Through a better understanding of molecular biology, many targeted therapies have emerged as new alternatives for various autoimmune diseases. Various janus kinase (JAK) and signal transducer and activator of transcription (STAT) proteins form signaling pathways, which transmit extracellular cytokine signals to the nucleus and induce DNA transcriptions. By inhibiting JAK, T-cell-mediated inflammatory responses are suppressed. Increasing evidence suggests that JAK inhibitors (JAKis) are effective in the treatment of many autoimmune diseases, including AA. Among these, several studies on tofacitinib, ruxolitinib, and baricitinib in AA had been published, demonstrating promising outcomes of these agents. Unlike oral formulations, efficacy of topical forms of tofacitinib and ruxolitinib reported in these studies is still unsatisfactory and requires improvement. This review aims to summarize evidence of the efficacy and safety of JAKis in the treatment of AA.

Adoptive Transfer of Interleukin-21-stimulated Human CD8+ T Memory Stem Cells Efficiently Inhibits Tumor Growth.

Memory stem T (TSCM) cells, a new subset of memory T cells with self-renewal and multipotent capacities, are considered as a promising candidates for adoptive cellular therapy. However, the low proportion of human TSCM cells in total CD8+ T cells limits their utility. Here, we aimed to induce human CD8+ TSCM cells by stimulating naive precursors with interleukin-21 (IL-21). We found that IL-21 promoted the generation of TSCM cells, described as CD45RA+CD45RO−CD62L+CCR7+CD122+CD95+ cells, with a higher efficiency than that observed with other common γ-chain cytokines. Upon adoptive transfer into an A375 melanoma mouse model, these lymphocytes mediated much stronger antitumor responses. Further mechanistic analysis revealed that IL-21 activated the Janus kinase signal transducer and activator of transcription 3 pathway by upregulating signal transducer and activator of transcription 3 phosphorylation and consequently promoting the expression of T-bet and suppressor of cytokine signaling 1, but decreasing the expression of eomesodermin and GATA binding protein 3. Our findings provide novel insights into the generation of human CD8+ TSCM cells and reveal a novel potential clinical application of IL-21.

Obovatol inhibits the growth and aggressiveness of tongue squamous cell carcinoma through regulation of the EGF‑mediated JAK‑STAT signaling pathway.

Migration and invasion are the most important characteristics of human malignancies which limit cancer drug therapies in the clinic. Tongue squamous cell carcinoma (TSCC) is one of the rarest types of cancer, although it is characterized by a higher incidence, rapid growth and greater potential for metastasis compared with other oral neoplasms worldwide. Studies have demonstrated that the phenolic compound obovatol exhibits anti‑tumor effects. However, the potential mechanisms underlying obovatol‑mediated signaling pathways have not been completely elucidated in TSCC. The present study investigated the anti‑tumor effects and potential molecular mechanisms mediated by obovatol in TSCC cells and tissues. The results of the present study demonstrated that obovatol exerted cytotoxicity in SCC9 TSCC cells, and inhibited their migration and invasion. In addition, obovatol induced apoptosis in SCC9 TSCC cells by increasing caspase 9/3 and apoptotic protease enhancing factor 1 expression levels. Western blot analysis demonstrated that obovatol inhibited the expression of pro‑epidermal growth factor (EGF), Janus kinase (JAK), and signal transducer and activator of transcription (STAT) in SCC9 TSCC cells. A study of the molecular mechanisms demonstrated that depletion of EGF reversed the obovatol‑mediated inhibition of SCC9 TSCC cell growth and aggressiveness. Animal experiments indicated that obovatol significantly inhibited TSCC tumor growth and increased the number of apoptotic cells in tumor tissues. In conclusion, the results of the present study provided scientific evidence that obovatol inhibited TSCC cell growth and aggressiveness through the EGF‑mediated JAK‑STAT signaling pathway, suggesting that obovatol may be a potential anti‑TSCC agent.

Combined deletion of the fibronectin-type III domains and the stalk region results in ligand-independent, constitutive activation of the Interleukin 6 signal-transducing receptor gp130

Gp130 is the common receptor within the Interleukin 6 cytokine family. Gp130 consists of 6 extracellular domains followed by a small stalk region connecting the last extracellular domain with the trans-membrane domain. Whereas the first three extracellular domains bind to IL-6-type cytokines, the domains 4–6 are needed for correct positioning of the intracellular domains to facilitate Janus kinase activation after cytokine binding. Interestingly, deletion within the cytokine-binding domain resulted in cytokine-independent constitutive activation of mutant gp130 receptors. Here, we tested the hypothesis, if deletions of the stalk region and/or domains 4–6 of gp130 might also result in constitutive receptor activation. Shortening of the stalk region of gp130 alone did, however, not result in constitutive receptor activation, whereas a gp130 receptor deletion variant only consisting of the three N-terminal cytokine binding domains but lacking all FNIII domains was biologically inactive. Importantly, combined deletion of the three FNIII domains plus shortening of the stalk region of gp130 resulted in ligand-independent, constitutive receptor activation of gp130.

MiR-26a-5p potentiates metastasis of human lung cancer cells by regulating ITGβ8- JAK2/STAT3 axis

Most lung cancer patients die of metastasis. Recent studies have indicated that dysregulated microRNAs (miRNAs) are involved not only in tumorigenesis, but also in metastasis. In the present study, we found that over-expression of miR-26a-5p potentiated the migration and invasion of lung cancer cells evidenced by wound healing assay and transwell assay, and metastasis-related genes MMP-9 and CD44 were up-regulated. We identified integrin-beta8 (ITGβ8) as a novel target of miR-26a, and ITGβ8 expression was negatively correlated with miR-26a-5p expression in lung cancer specimens. Mechanism study showed that miR-26a-5p enhanced lung cancer cell metastasis via activation of Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway, and ITGβ8 mediated the activation of JAK2/STAT3 pathway by miR-26a-5p. By using in vivo imaging technology, we found that miR-26a-5p enhanced both tumor growth and metastasis in vivo; and activated JAK2/STAT3 pathway. Taken together, our results demonstrated that miR-26a-5p potentiated lung cancer cell metastasis via JAK2/STAT3 pathway by targeting ITGβ8. This finding provides insights into the mechanism underlying miRNAs regulation on lung cancer metastasis; and suggests miR-26a-5p as a therapeutic target for lung cancer treatment.

Expression of p53 and its mechanism in prostate cancer.

The present study aimed to investigate the expression of tumor protein p53 (p53), and its mechanism of function, in prostate cancer (PC). Small interfering RNA (siRNA) was used to interfere with p53 expression in the PC cell line, DU145. Cell viability and p53 expression were analyzed using cell counting kit-8 (CCK-8) and western blotting. The effects of p53 expression on the proliferation, migration and adhesion abilities of PC cells were analyzed using Cell Counting kit-8, Transwell and adhesion assays. Changes in cell proliferation, migration and adhesion ability were observed following treatment with extracellular signal-regulated kinase (ERK) inhibitor, PD184352, and janus kinase (JNK) inhibitor, SP60012. The expression level of p53 declined 24 h after siRNA transfection (P<0.05). Furthermore, JNK and ERK, downstream proteins of the focal adhesion kinase (FAK)-Src proto-oncogene, non-receptor tyrosine kinase (Src) signaling pathway, were activated. These effects were associated with reduced proliferation, migration and adhesion abilities of PC cells compared with untransfected control cells (P<0.05). PD184352 and SP600125 treatments also resulted in reduced proliferation, migration and adhesion abilities of PC cells (P<0.05). In conclusion, PC cells exhibited low p53 expression, and the proliferation, migration and adhesion abilities of PC cells were promoted by inhibiting the activation of JNK and ERK. Together, these results suggest that p53 has potential as a therapeutic target in PC.

Hydrogen-rich solution attenuates myocardial injury caused by cardiopulmonary bypass in rats via the Janus-activated kinase 2/signal transducer and activator of transcription 3 signaling pathway.

The incidence of complications and mortality following open-heart surgery with cardiopulmonary bypass (CPB) is associated with the severity of the myocardial injury that occurs during surgery. Hydrogen-rich solution (HRS) may prevent antioxidant stress and inhibit apoptosis and inflammation. The present study was designed to investigate the effects of HRS on CPB-induced myocardial injury, and to investigate its potential regulation of the Janus-activated kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway. The HRS treatment resulted in the significant upregulation of malonyl dialdehyde (MDA) and myeloperoxidase (MPO), whilesuperoxide dismutase (SOD) levels were significantly downregulated, compared with the Sham group (P<0.05). Additionally, HRS treatment improved myocardial injury, and decreased the expression levels of cardiac troponins, heart-type fatty acid binding protein, interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, MDA and MPO, and increased SOD release in CPB rats (P<0.05). Additionally, in the CPB group without the HRS treatment, the expression levels of B-cell lymphoma (Bcl)-2, JAK2, phospho-JAK2 (p-JAK2), STAT3 and phospho-STAT3 (p-STAT3) were significantly decreased, and Bax was significantly increased, compared with the Sham group (P<0.05). By contrast, compared with the CPB group, the expression levels of B-cell lymphoma 2 (Bcl-2), JAK2, phosphorylated (p)-JAK2, STAT3 and p-STAT3 in the HRS group were significantly increased, and Bcl-2-associated X protein expression was significantly decreased (P<0.05). In JAK2 knockdown experiments using siRNA, HRS treatment following hypoxia/reoxygenation also significantly increased the viability of myocardial cells, decreased the rate of myocardial cell apoptosis, elevated the levels of SOD and suppressed the release of MDA and lactate dehydrogenase in the control siRNA and CPB groups (P<0.05). Furthermore, JAK2 siRNA attenuated these protective effects of HRS (P<0.05 vs. control siRNA, HRS and CPB groups). Additionally, the results demonstrated that the HRS treatment significantly increased the expression levels of p-JAK2, p-STAT3 and Bcl-2 in myocardial cells following hypoxia and decreased Bax expression in the control siRNA and CPB groups (P<0.05). In addition, JAK2 siRNA was determined to attenuate these effects of HRS (P<0.05 vs. control siRNA, HRS and CPB groups). Taken together, these results indicated that HRS may alleviate CPB-induced myocardial injury, inhibit myocardial cell apoptosis and protect myocardial cells through regulation of the JAK2/STAT3 signaling pathway.