Radiation with STAT3 Blockade Triggers Dendritic Cell-T cell Interactions in the Glioma Microenvironment and Therapeutic Efficacy.

PURPOSE: Patients with central nervous system (CNS) tumors are typically treated with radiotherapy, but this is not curative and results in the upregulation of phosphorylated STAT3 (p-STAT3), which drives invasion, angiogenesis, and immune suppression. Therefore, we investigated the combined effect of an inhibitor of STAT3 and whole-brain radiotherapy (WBRT) in a murine model of glioma. EXPERIMENTAL DESIGN: C57BL/6 mice underwent intracerebral implantation of GL261 glioma cells, WBRT, and treatment with WP1066, a blood-brain barrier-penetrant inhibitor of the STAT3 pathway, or the two in combination. The role of the immune system was evaluated using tumor rechallenge strategies, immune-incompetent backgrounds, immunofluorescence, immune phenotyping of tumor-infiltrating immune cells (via flow cytometry), and NanoString gene expression analysis of 770 immune-related genes from immune cells, including those directly isolated from the tumor microenvironment. RESULTS: The combination of WP1066 and WBRT resulted in long-term survivors and enhanced median survival time relative to monotherapy in the GL261 glioma model (combination vs. control P < 0.0001). Immunologic memory appeared to be induced, because mice were protected during subsequent tumor rechallenge. The therapeutic effect of the combination was completely lost in immune-incompetent animals. NanoString analysis and immunofluorescence revealed immunologic reprograming in the CNS tumor microenvironment specifically affecting dendritic cell antigen presentation and T-cell effector functions. CONCLUSIONS: This study indicates that the combination of STAT3 inhibition and WBRT enhances the therapeutic effect against gliomas in the CNS by inducing dendritic cell and T-cell interactions in the CNS tumor.

Sinomenine hydrochloride inhibits the progression of plasma cell mastitis by regulating IL-6/JAK2/STAT3 pathway.

Plasma cell mastitis (PCM) is a special form of mastitis characterized by periductal inflammation and large-scale plasma cell infiltration. At present, the recurrence rate of PCM after excision is quite high, making PCM a major problem for mammary surgeons. However, no effective drug exists for the treatment of PCM. Numerous studies have demonstrated that Sinomenine hydrochloride (SH) has potent anti-inflammatory and immunoregulatory properties. However, the efficacy and the underlying mechanisms of SH in the treatment of PCM remain unclear. In the present study, we first investigated the therapeutic effects of SH in the PCM mouse model and clarified the possible mechanisms. We found that the levels of plasmocytes and lymphocytes infiltration were alleviated significantly in the 100 mg/kg SH group compared to the control group. In addition, few CD138+ plasma cells were found in the mammary glands of the 100 mg/kg SH group. The levels of Bcl-2 in the 100 mg/kg SH group were dramatically decreased compared with those in the saline group. Mechanistically, we demonstrated that SH inhibited the progression of PCM mainly through downregulating IL-6/JAK2/STAT3 levels. Collectively, our results suggested that SH could inhibit the progression of PCM by suppressing IL-6/JAK2/STAT3 cascades and ultimately achieve a therapeutic effect in PCM. This study provides theoretical support for the clinical application of SH in the treatment of PCM.

Inhibition of ErbB kinase signalling promotes resolution of neutrophilic inflammation.

Neutrophilic inflammation with prolonged neutrophil survival is common to many inflammatory conditions, including chronic obstructive pulmonary disease (COPD). There are few specific therapies that reverse neutrophilic inflammation, but uncovering mechanisms regulating neutrophil survival is likely to identify novel therapeutic targets. Screening of 367 kinase inhibitors in human neutrophils and a zebrafish tail fin injury model identified ErbBs as common targets of compounds that accelerated inflammation resolution. The ErbB inhibitors gefitinib, CP-724714, erbstatin and tyrphostin AG825 significantly accelerated apoptosis of human neutrophils, including neutrophils from people with COPD. Neutrophil apoptosis was also increased in Tyrphostin AG825 treated-zebrafish in vivo. Tyrphostin AG825 decreased peritoneal inflammation in zymosan-treated mice, and increased lung neutrophil apoptosis and macrophage efferocytosis in a murine acute lung injury model. Tyrphostin AG825 and knockdown of egfra and erbb2 by CRISPR/Cas9 reduced inflammation in zebrafish. Our work shows that inhibitors of ErbB kinases have therapeutic potential in neutrophilic inflammatory disease.

Effect of propofol on myocardial ischemia/reperfusion injury in rats through JAK/STAT signaling pathway.

OBJECTIVE: The aim of this study was to investigate the influences of propofol on myocardial ischemia/reperfusion injury in rats through the Janus kinase/signal transducers and the activators of transcription (JAK/STAT) signaling pathway. MATERIALS AND METHODS: A total of 48 Sprague-Dawley (SD) rats were randomly divided into four groups, including: the sham-operation group (n=12), the model group (n=12), the propofol group (n=12) and the inhibitor group (n=12). The rats in the sham-operation group only received thoracotomy, without the modeling of the ischemia/reperfusion injury. The model of myocardial ischemia/reperfusion injury was established in the rats of the model group, and the rats were given normal saline for intervention. The rats in the propofol group were utilized to prepare the model of myocardial ischemia/reperfusion injury and were intervened with propofol. Meanwhile, the rats in the inhibitor group received intervention with AG490 after the establishment of myocardial ischemia/reperfusion injury model. Immunohistochemistry was applied to detect the expressions of B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax). Western blotting was utilized to measure the relative protein expressions of phosphorylated JAK2 (p-JAK2) and p-STAT3. The messenger ribonucleic acid (mRNA) expressions of Bax and Bcl-2 were determined via quantitative Polymerase Chain Reaction (qPCR). Furthermore, cell apoptosis was examined using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. RESULTS: Immunohistochemistry results showed that compared with the sham-operation group, the positive expression of Bax remarkably increased (p<0.05), while Bcl-2 notably decreased (p<0.05) in the model group, propofol group, and inhibitor group. The propofol group and inhibitor group showed a significant lower positive expression of Bax (p<0.05) and evident higher positive expression of Bcl-2 (p<0.05) when compared with the model group. However, there were no significant differences in the positive expressions of Bax and Bcl-2 between the propofol group and inhibitor group (p>0.05). According to the results of Western blotting, the relative protein expression levels of p-JAK2 and p-STAT3 proteins were remarkably elevated in the model group, propofol group and inhibitor group in comparison with those in the sham-operation group (p<0.05). Propofol group and inhibitor group exhibited remarkably lower protein expression levels of p-JAK2 and p-STAT3 compared with the model group (p<0.05). However, no significant differences were observed in the protein expressions of p-JAK2 and p-STAT3 between propofol group and inhibitor group (p>0.05). The results of qPCR manifested that the mRNA expression of Bax was notably higher (p<0.05), whereas Bcl-2 was significantly lower (p<0.05) in the model group, propofol group and inhibitor group than those of the sham-operation group. Compared with the model group, the mRNA expression of Bax was evidently declined (p<0.05), while Bcl-2 was significantly elevated (p<0.05) in the propofol group and inhibitor group. Meanwhile, there were no evident differences in the mRNA expressions of Bax and Bcl-2 between the propofol group and inhibitor group (p>0.05). Subsequent TUNEL assay indicated that the model group, propofol group, and inhibitor group showed remarkably higher apoptosis rate than the sham-operation group (p<0.05). Moreover, the apoptosis rate was remarkably reduced in the propofol group and inhibitor group in comparison with the model group (p<0.05). However, no significant difference was observed in the apoptosis rate between propofol group and inhibitor group (p>0.05). CONCLUSIONS: Propofol inhibits myocardial cell apoptosis after myocardial ischemia/reperfusion injury by repressing the JAK/STAT signaling pathway.

Anti-vasospastic Effects of Epidermal Growth Factor Receptor Inhibitors After Subarachnoid Hemorrhage in Mice.

Subarachnoid hemorrhage (SAH) is a devastating disease. Cerebral vasospasm is still an important cause of post-SAH poor outcomes, but its mechanisms remain unveiled. Activation of epidermal growth factor receptor (EGFR) is suggested to cause vasoconstriction in vitro, but no report has demonstrated the involvement of EGFR in vasospasm development after SAH in vivo. Cross-talk of EGFR and vascular endothelial growth factor (VEGF) receptor, which may affect post-SAH vasospasm, was also reported in cancer cells, but has not been demonstrated in post-SAH vasospasm. The aim of this study was to investigate whether EGFR as well as EGFR-VEGF receptor cross-talk engage in the development of cerebral vasospasm in a mouse SAH model. C57BL6 mice underwent endovascular perforation SAH or sham modeling. At 30 min post-modeling, mice were randomly administrated vehicle or 2 doses of selective EGFR inhibitors intracerebroventricularly. A higher dose of the inhibitor significantly prevented post-SAH neurological impairments at 72 h and vasospasm at 24 h associated with suppression of post-SAH activation of EGFR and extracellular signal-regulated kinase (ERK) 1/2 in the cerebral artery wall, especially in the smooth muscle cell layers. Anti-EGFR neutralizing antibody also showed similar effects. However, neither expression levels of VEGF nor activation levels of a major receptor of VEGF, VEGF receptor-2, were affected by SAH and two kinds of EGFR inactivation. Thus, this study first showed that EGFR-ERK1/2 pathways may be involved in post-SAH vasospasm development, and that EGFR-VEGF receptor cross-talk may not play a significant role in the development of vasospasm in mice.

Tescalcin/c-Src/IGF1Rß-mediated STAT3 activation enhances cancer stemness and radioresistant properties through ALDH1.

Tescalcin (TESC; also known as calcineurin B homologous protein 3, CHP3) has recently reported as a regulator of cancer progression. Here, we showed that the elevation of TESC in non-small cell lung cancer (NSCLC) intensifies epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) properties, consequently enhancing the cellular resistance to γ-radiation. TESC expression and the phosphorylation (consequent activation) of signal transducer and activator of transcription 3 (STAT3) were upregulated in CSC-like ALDH1high cells than in ALDH1low cells sorted from A549 NSCLC cells. Knockdown of TESC suppressed CSC-like properties as well as STAT3 activation through inhibition of insulin-like growth factor 1 receptor (IGF1R), a major signaling pathway of lung cancer stem cells. TESC activated IGF1R by the direct recruitment of proto-oncogene tyrosine kinase c-Src (c-Src) to IGF1Rß complex. Treatment of IGF1R inhibitor, AG1024, also suppressed c-Src activation, implicating that TESC mediates the mutual activation of c-Src and IGF1R. STAT3 activation by TESC/c-Src/IGF1R signaling pathway subsequently upregulated ALDH1 expression, which enhanced EMT-associated CSC-like properties. Chromatin immunoprecipitation and luciferase assay demonstrated that STAT3 is a potential transcription activator of ALDH1 isozymes. Ultimately, targeting TESC can be a potential strategy to overcome therapeutic resistance in NSCLC caused by augmented EMT and self-renewal capacity.

Stat3/Oct-4/c-Myc signal circuit for regulating stemness-mediated doxorubicin resistance of triple-negative breast cancer cells and inhibitory effects of WP1066.

Doxorubicin (Dox) is widely used in the treatment of triple-negative breast cancer cells (TNBCs), however resistance limits its effectiveness. Cancer stem cells (CSCs) are associated with Dox resistance in MCF-7 estrogen receptor positive breast cancer cells. Signal transducer and activator of transcription 3 (Stat3) may functionally shift non-CSCs towards CSCs. However, whether Stat3 drives the formation of CSCs during the development of resistance in TNBC, and whether a Stat3 inhibitor reverses CSC-mediated Dox resistance, remains to be elucidated. In the present study, human MDA-MB-468 and murine 4T1 mammary carcinoma cell lines with the typical characteristics of TNBCs, were compared with estrogen receptor-positive MCF-7 cells as a model system. The MTT assay was used to detect cytotoxicity of Dox. In addition, the expression levels of CSC-specific markers and transcriptional factors were measured by western blotting, immunofluorescence staining and flow cytometry. The mammosphere formation assay was used to detect stem cell activity. Under long-term continuous treatment with Dox at a low concentration, TNBC cultures not only exhibited a drug-resistant phenotype, but also showed CSC properties. These Dox-resistant TNBC cells showed activation of Stat3 and high expression levels of pluripotency transcription factors octamer-binding transcription factor-4 (Oct-4) and c-Myc, which was different from the high expression of superoxide dismutase 2 (Sox2) in Dox-resistant MCF-7 cells. WP1066 inhibited the phosphorylation of Stat3, and decreased the expression of Oct-4 and c-Myc, leading to a reduction in the CD44-positive cell population, and restoring the sensitivity of the cells to Dox. Taken together, a novel signal circuit of Stat3/Oct-4/c-Myc was identified for regulating stemness-mediated Dox resistance in TNBC. The Stat3 inhibitor WP1066 was able to overcome the resistance to Dox through decreasing the enrichment of CSCs, highlighting the therapeutic potential of WP1066 as a novel sensitizer of Dox-resistant TNBC.

Nucleolin and ErbB2 inhibition reduces tumorigenicity of ErbB2-positive breast cancer.

ErbB2, a member of the ErbB family of receptor tyrosine kinases, is an essential player in the cell's growth and proliferation signaling pathways. Amplification or overexpression of ErbB2 is observed in ∼30% of breast cancer patients, and often drives cellular transformation and cancer development. Recently, we have shown that ErbB2 interacts with the nuclear-cytoplasmic shuttling protein nucleolin, an interaction which enhances cell transformation in vitro, and increases mortality risk and disease progression rate in human breast cancer patients. Given these results, and since acquired resistance to anti-ErbB2-targeted therapy is a major obstacle in treatment of breast cancer, we have examined the therapeutic potential of targeting the ErbB2-nucleolin complex. The effect of the nucleolin-specific inhibitor GroA (AS1411) on ErbB2-positive breast cancer was tested in vivo, in a mouse xenograft model for breast cancer; as well as in vitro, alone and in combination with the ErbB2 kinase-inhibitor tyrphostin AG-825. Here, we show that in vivo treatment of ErbB2-positive breast tumor xenografts with GroA reduces tumor size and leads to decreased ErbB2-mediated signaling. Moreover, we found that co-treatment of breast cancer cell lines with GroA and the ErbB2 kinase-inhibitor tyrphostin AG-825 enhances the anti-cancer effects exerted by GroA alone in terms of cell viability, mortality, migration, and invasiveness. We, therefore, suggest a novel therapeutic approach, consisting of combined inhibition of ErbB2 and nucleolin, which has the potential to improve breast cancer treatment efficacy.

[Intrathecal injection of AG-490 reduces bone-cancer-induced spinal cord astrocyte reaction and thermal hyperalgesia in a mouse model].

OBJECTIVE: To investigate the role of spinal interleukin-6-Janus kinase 2 (IL-6-JAK2) signaling transduction pathway in regulating astrocytes activation during the maintenance of bone cancer pain (BCP).
 Methods: NCTC 2472 fibrosarcoma cells were injected into the femur marrow cavity in C3H/HeNCrlVr male mice to establish BCP model and they were replaced by the equal volume of α-MEM in the sham model. The paw withdrawal latency (PWL) was measured after inoculation of tumor cells. The lumbar enlargement of spinal cord (L3-L5) was isolated, and Real-time RT-PCR and Western blot were used to detect the expression of spinal glial fibrillary acidic protein (GFAP) and JAK2 mRNA and protein, respectively. The expression level of spinal GFAP mRNA indirectly reflect astrocytes activation level. Pain behaviors and spinal cord GFAP mRNA and protein expression were observed at the given time points after intrathecal administration of JAK2 antagonist AG-490.
 Results: The PWL at 10, 14, 21 d after operation in BCP model group were significantly shorter than that in the sham group (P<0.05); the spinal GFAP and JAK2 mRNA and protein levels were higher in the BCP model group in comparison to mice in the sham group (P<0.05); intrathecal injection of JAK2 agonist AG-490 (30 or 90 nmol) significantly alleviated PWL, and downregulated the expression of spinal GFAP mRNA and protein (P<0.05).
 Conclusion: The IL-6-JAK2 signaling pathway plays an important role in maintaining the BCP by regulating the expression of GFAP in the spinal cord. Intrathecal injection of AG-490 can reduce the BCP, and inhibit the activation of IL-6-JAK2 signaling pathway, which may be one of the mechanisms for spinal astrocyte activation.

The epidermal growth factor receptor inhibitor AG1478 inhibits eosinophilic inflammation in upper airways.

Mucus hypersecretion and eosinophil infiltration are important characteristics of eosinophilic inflammation in upper airways, such as allergic rhinitis and chronic rhinosinusitis with nasal polyp. EGFR transactivation induces mucus and inflammatory cytokine secretion from airway epithelial cells. However, the roles of EGFR in eosinophilic inflammation in upper airways are still unknown. The purpose of the study is to elucidate the effects of the EGFR inhibitor AG1478 on eosinophilic airway inflammation. AG1478 significantly inhibited thrombin-induced GM-CSF secretion from nasal epithelial cells and thrombin-induced secretion of eotaxin-1 and RANTES from nasal fibroblasts. Intranasal instillation of AG1478 inhibited OVA-induced goblet cell metaplasia, mucus production and eosinophil/neutrophil infiltration in rat nasal epithelium, as did intraperitoneal injection of AG1478. These results indicate that EGFR transactivation plays an important role in eosinophilic airway inflammation. Intranasal instillation of an EGFR inhibitor may be a new therapeutic approach for the treatment of intractable eosinophilic inflammation in upper airways.

Transforming growth factor ß1 promotes migration and invasion in HepG2 cells: Epithelial­to­mesenchymal transition via JAK/STAT3 signaling.

Transforming growth factor ß1 (TGFß1) is a cytokine with multiple functions. TGFß1 significantly induces migration and invasion of liver cancer cells. However, the molecular mechanisms underlying this effect remain unclear. Epithelial­to­mesenchymal transition (EMT) is crucial for the development of invasion and metastasis in human cancers. The aim of the present study was to determine whether TGFß1­induced EMT promoted migration and invasion in HepG2 cells. The underlying mechanism and the effect of EMT on HepG2 cells were also investigated. The results demonstrated that TGFß1 may induce EMT to promote migration and invasion of HepG2 cells, and this effect depends on activation of the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) signaling pathway. JAK/STAT3 signaling is involved in human malignancies, including lung cancer, and is implicated in cell transformation, tumorigenicity, EMT and metastasis. In the present study, TGFß1 also activated JAK/STAT3 signaling in HepG2 cells and promoted Twist expression, but these events were abolished by treatment with the STAT3 inhibitor AG490. Additionally, Twist siRNA blocked TGFß1­induced EMT. Thus, TGFß1 was shown to induce EMT, thereby promoting the migration and invasion of HepG2 cells via JAK/STAT3/Twist signaling.

Src-dependent EGFR transactivation regulates lung inflammation via downstream signaling involving ERK1/2, PI3Kδ/Akt and NFκB induction in a murine asthma model.

The molecular mechanisms underlying asthma pathogenesis are poorly characterized. In this study, we investigated (1) whether Src mediates epidermal growth factor receptor (EGFR) transactivation; (2) if ERK1/2, PI3Kδ/Akt and NF-κB are signaling effectors downstream of Src/EGFR activation; and (3) if upstream inhibition of Src/EGFR is more effective in downregulating the allergic inflammation than selective inhibition of downstream signaling pathways. Allergic inflammation resulted in increased phosphorylation of EGFR, Akt, ERK1/2 and IκB in the lung tissues from ovalbumin (OVA)-challenged BALB/c mice. Treatment with inhibitors of Src (SU6656) or EGFR (AG1478) reduced EGFR phosphorylation and downstream signaling which resulted in the inhibition of the OVA-induced inflammatory cell influx in bronchoalveolar lavage fluid (BALF), perivascular and peribronchial inflammation, fibrosis, goblet cell hyper/metaplasia and airway hyper-responsiveness. Treatment with pathway-selective inhibitors for ERK1/2 (PD89059) and PI3Kδ/Akt (IC-87114) respectively, or an inhibitor of NF-κB (BAY11-7085) also reduced the OVA-induced asthmatic phenotype but to a lesser extent compared to Src/EGFR inhibition. Thus, Src via EGFR transactivation and subsequent downstream activation of multiple pathways regulates the allergic airway inflammatory response. Furthermore, a broader upstream inhibition of Src/EGFR offers an attractive therapeutic alternative in the treatment of asthma relative to selectively targeting the individual downstream signaling effectors.

Insulin growth factor inhibitor as a potential new anti-schistosoma drug: An in vivo experimental study.

BACKGROUND AND OBJECTIVE: Tyrphostin "AG1024" is an insulin growth factor-1 receptor (IGF-1R) inhibitor that displayed an effect on the viability of larval and mature schistosomes in vitro. We sought to investigate the possible in vivo role of AG1024 as a potential new anti-Schistosoma drug against immature and adult stages of Schistosoma mansoni and its effect on the degree of hepatic fibrosis and insulin pathway. METHODS: The study included a control non-infected group and 5 groups of S. manosoni-infected CD-1 albino mice (20 mice each) assigned to treatment as follows: vehicle-treated, early AG1024, 30µg/100µl DMSO, IP for 10days started 30days post-infection (dpi), early praziquantel (PZQ), 500mg/kg orally for 2days (30dpi), late AG1024 (60dpi), and late PZQ (60dpi). All mice were sacrificed 12 weeks post-infection. Parasitological, chemical and histopathological parameters were studied. Immunohistochemistry of TGF-ß and GLUT4 in liver sections was done to further evaluate the effect of AG1024 on the degree of hepatic fibrosis and insulin signaling pathway, respectively. RESULTS: Early administration of AG1024 (30dpi) resulted in significant reduction of hepatic and intestinal tissue egg count with a reduction of 79.99% and 89.1% respectively. Late administration of AG1024 (60dpi) led to 77.78% reduction of intestinal eggs count; however, hepatic egg count wasn't reduced significantly. No reduction in worm burden was recorded for both administration regimens. Both regimens lead to significant decrease of both ALT and AST, mean hepatic granuloma diameter but an increase in fibrosis percentage (65.2% and 55% respectively). Both early and late treatment with AG1024 showed a significant increment of TGF-ß expression by 71.4% and 39.3%, respectively (p<0.0001) compared to PZQ-treated and infected non-treated groups. Hepatic GLUT4 expression was significantly decreased compared to infected non-treated group (p<0.001) and the corresponding PZQ-treated group. CONCLUSION: Early AG1024 administration induced more significant results compared to early PZQ with a promising activity against egg production and subsequent reduction of tissue egg load rather than direct schistosomicidal effect; however, it induced granuloma fibrosis, TGF-ß expression, and disrupted the insulin signaling pathway.

B7-H3 is related to tumor progression in ovarian cancer.

B7-H3, a co-stimulatory molecule, has been found expressed in ovarian cancer, but its role and mechanism is not clear. In this study, we further verified the expression of B7-H3 in ovarian carcinoma and normal epithelial ovarian tissues. Three ovarian cancer cell lines, A2780, SKOV3 and HO8910 were selected to explore the effects of B7-H3 on proliferation, apoptosis, migration and invasion. We found that B7-H3 was mainly located in the cytoplasm of ovarian cancer cells as determined by immunofluorescence staining. The ability of cell invasion, migration, proliferation decreased after silencing B7-H3 whereas the apoptosis increased, which was related to the upregulation of Bax, caspase-8, cleaved caspase-8 and the downregulation of Bcl-2, Bcl-xl, matrix metalloproteinase-2 (MMP2) by western blotting. In addition, B7-H3 enhanced the H08910 cell capacities in invasion, migration and proliferation. Expression of the phosphorylation signal transducer and activator of transcription 3 (pStat3) molecules and their upstream molecules phosphorylation Janus kinase 2 (pJak2) were significantly increased. In order to investigate whether B7-H3 plays a role in this pathway, we treated the overexpressed HO8910 cells with AG490 (inhibitors of Jak2). Our findings revealed that B7-H3 affect ovarian cancer progression through the Jak2/Stat3 pathway, indicating that B7-H3 has the potential to be a useful prognostic marker.

Influence and mechanism of 5-aminolevulinic acid-photodynamic therapy on the metastasis of esophageal carcinoma.

BACKGROUD: Photodynamic therapy (PDT) for the treatment of esophageal cancer was more and more popularly used since it was approved for the treatment of advanced esophageal cancer in 1996. It has been reported to influence the tumor growth and metastasis via a variety of signaling pathways, but its mechanism remains to be further studied. This research studied the effects of ALA-PDT on esophageal carcinoma in vitro and in vivo, discovering its molecular regulating mechanism and the way to enhence the PDT effect. METHODS: Eca-109 cells were incubated with a medium containing EGFR tyrphostin AG1478 or PI3K inhibitor LY294002, then with ALA, and the cells were irradiated with the laser 6h later. The cell viability was measured with MTT assay, and the migration ability was detected by transwell experiments 24h post-ALA-PDT. The gene and protein expression on EGFR/PI3K/AKT signaling pathway was analyzed by realtime PCR and Western blotting respectively. Then, RFP-Eca-109 burdened nude mice model was constructed, and were treated with ALA-PDT when the tumor volume reached 150-350mm3. The gene and protein expression were analyzed 24h and 50days post-ALA-PDT. RESULTS: Our study showed that ALA-PDT respectively combined with AG1478, LY294002 could synergistically reduce the growth and migration ability of the Eca-109 cells in vitro and significantly down-regulate the protein expression of EGFR/PI3K and PI3K/AKT, meanwhile, significantly down-regulate the gene expression of EGFR when combining with AG1478. Forthermore, ALA-PDT could significantly decrease the tumor growth and metastasis and down-regulate the gene expression of EGFR and the protein expression of EGFR and PI3K in the tumor of mice. CONCLUSION: This study revealed a molecular mechanism of ALA-PDT and developed a new modality application of therapy, by combining ALA-PDT with small molecular inhibitors, for better effect in the clinical practice of esophageal carcinoma.

STAT3 inhibition by WP1066 suppresses the growth and invasiveness of bladder cancer cells.

Signal transducer and activator of transcription 3 (STAT3) regulates the expression of genes mediating cell survival, proliferation and angiogenesis and is aberrantly activated in various types of malignancies, including bladder cancer. We examined whether it could be a novel therapeutic target for bladder cancer using the STAT3 inhibitor WP1066. In T24 and UMUC-3 bladder cancer cells, 5 µM WP1066 prevented the phosphorylation of STAT3 and 2.5 µM WP1066 decreased cell survival and proliferation significantly (P<0.01). WP1066 also induced apoptosis accompanied by the suppression of the expression of Bcl-2 and Bcl-xL in T24 cells. Moreover, the covered area in a wound and the number of cells invading through a Matrigel chamber decreased significantly (P<0.01) when cells were treated with WP1066. The activities of MMP-2 and MMP-9 were also decreased by treatment with 10 µM WP1066. Our results revealed that using WP1066 to inhibit the STAT3 signaling pathway suppressed the viability and invasiveness of bladder cancer cells effectively and could be a novel therapeutic strategy against bladder cancer.

Reversible meiotic arrest of bovine oocytes by EGFR inhibition and follicular hemisections.

The objective of this study was to investigate the effects of inhibiting the epidermal growth factor receptor (EGFR) pathway on meiosis blockage and resumption, mRNA expression of genes involved in oocyte maturation and cumulus expansion, and embryo development. Bovine cumulus-oocyte complexes (COCs) were cultured for 15 h in the presence of the EGFR inhibitor (AG1478) and follicular hemisections (FHS). Most of the oocytes (89.3%) remained at the germinal vesicle (GV) stage when cultured in the presence of FHS and 5 µM AG1478. The inhibitory effect was reversible as most oocytes (83.8%) completed meiosis after additional 20 h maturation. Embryo development to the blastocyst stage was similar (P > 0.05) between FHS and 5 µM AG1478 treated (39.3%) and control (41.1%) groups. In cumulus cells, mRNA abundance of early growth response protein 1 (EGR1), tumor necrosis factor alpha-induced protein 6 (TNFAIP6) and hyaluronan synthase 2 (HAS2) genes, and phosphorylated extracellular regulated kinase (p-ERK1/2) protein were lower in COCs treated with AG1478 plus FHS compared with FHS alone (P < 0.05). In granulosa cells of FHS, AG1478 treatment reduced transcript levels of PGR and ADAMTS1 (P < 0.05). The inhibitory effect of AG1478 on meiotic progression was not reverted by treatment with angiotensin II (ANG II) or prostaglandins (PGF2α or PGE2). This study demonstrates that inhibition of EGFR in the presence of FHS is a reliable approach to promote reversible arrest of bovine oocytes at the GV stage.

Cetuximab promotes SN38 sensitivity via suppression of heat shock protein 27 in colorectal cancer cells with wild-type RAS.

Combination treatment with cetuximab and CPT-11 produces beneficial and synergistic effects in wild-type RAS metastatic colorectal cancer (mCRC) patients. However, the mechanism underlying this synergism is not yet understood. We examined whether cetuximab had a synergistic effect with CPT-11 and its active metabolite, SN38, and examined the molecular mechanism of the synergism between cetuximab and SN38 in CRC cells with various mutational status. We hypothesized that cetuximab promotes sensitivity to SN38 via suppression of heat shock protein 27 (HSP27), a protein involved in multidrug resistance through blocking the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway, which is associated with chemosensitivity. Four human CRC cell lines with different RAS and BRAF mutational status were used. Expression levels of HSP27 protein correlated with SN38 sensitivity in these cell lines (R=0.841, p=0.159). Exposure to cetuximab and various concentration of AG490, an inhibitor of JAK2, STAT3 and HSP27 protein levels, except in the KRAS G12V mutant line, SW620. A synergistic effect of cetuximab in combination with SN38 was observed in RAS and BRAF wild-type cells (here, Caco2), but not in the three other RAS- or BRAF-mutated cell lines. These results indicate that cetuximab may promote sensitivity to SN38 via suppression of HSP27 through blocking the JAK/STAT pathway in Caco2 cells. The mutational status of numerous downstream effectors, such as RAS and BRAF, is important in mono- or combination therapy with cetuximab. In conclusion, cetuximab may promote SN38 sensitivity via suppression of HSP27, through blocking the JAK/STAT signaling pathway, and shows synergistic effects when combined with SN38 in wild-type RAS CRC cells.

α7 Nicotinic Acetylcholine Receptor Stimulation Attenuates Neuroinflammation through JAK2-STAT3 Activation in Murine Models of Intracerebral Hemorrhage.

Accounting for high mortality and morbidity rates, intracerebral hemorrhage (ICH) remains one of the most detrimental stroke subtypes lacking a specific therapy. Neuroinflammation contributes to ICH-induced brain injury and is associated with unfavorable outcomes. This study aimed to evaluate whether α7 nicotinic acetylcholine receptor (α7nAChR) stimulation ameliorates neuroinflammation after ICH. Male CD-1 mice and Sprague-Dawley were subjected to intracerebral injection of autologous blood or bacterial collagenase. ICH animals received either α7nAChR agonist PHA-543613 alone or combined with α7nAChR antagonist methyllycaconitine (MLA) or Janus kinase 2 (JAK2) antagonist AG490. Neurobehavioral deficits were evaluated at 24 hours, 72 hours, and 10 weeks after ICH induction. Perihematomal expressions of JAK2, signal transducer and activator of transcription 3 (STAT3), tumor necrosis factor-α (TNF-α), and myeloperoxidase (MPO) were quantified via Western blot. Histologic volumetric analysis of brain tissues was conducted after 10 weeks following ICH induction. PHA-543613 improved short-term neurobehavioral (sensorimotor) deficits and increased activated perihematomal JAK2 and STAT3 expressions while decreasing TNF-α and MPO expressions after ICH. MLA reversed these treatment effects. PHA-543613 also improved long-term neurobehavioral (sensorimotor, learning, and memory) deficits and ameliorated brain atrophy after ICH. These treatment effects were reduced by AG490. α7nAChR stimulation reduced neuroinflammation via activation of the JAK2-STAT3 pathway, thereby ameliorating the short- and long-term sequelae after ICH.

Migration of oral squamous cell carcinoma cells are induced by HGF/c-Met signalling via lamellipodia and filopodia formation.

The activation of receptor tyrosine kinases (RTKs) results in cellular effects including cell proliferation, survival, migration and invasion; RTKs also play an important role in tumourigenesis. It has been reported that EGFR signalling controls the migration of oral squamous cell carcinoma (OSCC) SAS and HSC3 cells but not of HSC4 cells, although the proliferation of HSC4 cells is regulated by EGF/EGFR. In the present study, we investigated the roles of EGFR and the c-Met signalling pathway in cell migration via filopodia and lamellipodia formation, which may be prerequisites for migration. To explore the role of c-Met in cell migration, we inhibited c-Met RTK activity using the c-Met inhibitor SU11274 and activated c-Met using hepatocyte growth factor (HGF) in three OSCC cell lines HSC4, SAS and Ca9-22 and investigated migration potency using a wound healing assay. We showed that inhibition of c-Met significantly suppressed, and activation of c-Met significantly promoted, the migration of OSCC cells. Additionally, the migration of SAS and Ca9-22 cells was inhibited by the EGFR inhibitors AG1478 and cetuximab and promoted by EGF treatment. Moreover, migration potency was correlated with lamellipodia formation. Furthermore, western blot analyses demonstrated that SU11274 decreased and HGF increased lamellipodin protein levels as well as phosphorylated c-Met levels. Collectively, we demonstrated that c-Met signalling induced lamellipodia formation by upregulating lamellipodin, thereby promoting the migration of OSCC cells.