azd-1480 and Disease-Models--Animal

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

Intratumoral heterogeneity is a hallmark of glioblastoma (GBM) tumors, thought to negatively influence therapeutic outcome. Previous studies showed that mesenchymal tumors have a worse outcome than the proneural subtype. Here we focus on STAT3 as its activation precedes the proneural-mesenchymal transition. We first establish a STAT3 gene signature that stratifies GBM patients into STAT3-high and -low cohorts. STAT3 inhibitor treatment selectively mitigates STAT3-high cell viability and tumorigenicity in orthotopic mouse xenograft models. We show the mechanism underlying resistance in STAT3-low cells by combining STAT3 signature analysis with kinome screen data on STAT3 inhibitor-treated cells. This allows us to draw connections between kinases affected by STAT3 inhibitors, their associated transcription factors and target genes. We demonstrate that dual inhibition of IGF-1R and STAT3 sensitizes STAT3-low cells and improves survival in mice. Our study underscores the importance of serially profiling tumors so as to accurately target individuals who may demonstrate molecular subtype switching.

Topics: Animals; Cell Survival; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Synergism; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Genetic Predisposition to Disease; Glioblastoma; Humans; Imidazoles; Insulin-Like Growth Factor Binding Protein 2; Mice; Pyrazines; Pyrazoles; Pyrimidines; Receptor, IGF Type 1; STAT3 Transcription Factor; Temozolomide; Xenograft Model Antitumor Assays

Janus kinase 2/signal transducer and activators of transcription 1 (JAK2/STAT1) signaling is a common pathway that contributes to numerous inflammatory disorders, including different forms of acute lung injury (ALI). However, the role of JAK2/STAT1 in ventilator-induced lung injury (VILI) and its underlying mechanism remain unclear. In this study, using lipopolysaccharide (LPS) inhalation plus mechanical ventilation as VILI mouse model, we found that the administration of JAK2 inhibitor AZD1480 markedly attenuated lung destruction, diminished protein leakage, and inhibited cytokine release. In addition, when mouse macrophage-like RAW 264.7 cells were exposed to LPS and cyclic stretch (CS), AZD1480 prevented cell autophagy, reduced apoptosis, and suppressed lactate dehydrogenase release by downregulating JAK2/STAT1 phosphorylation levels and inducing HMGB1 translocation from the nucleus to the cytoplasm. Furthermore, HMGB1 and STAT1 knockdown attenuated LPS+CS-induced autophagy and apoptosis in RAW 264.7 cells. In conclusion, these findings reveal the connection between the JAK2/STAT1 pathway and HMGB1 translocation in mediating lung inflammation and cell death in VILI, suggesting that these molecules may serve as novel therapeutic targets for VILI.

Topics: Animals; Cell Death; Disease Models, Animal; Drug Evaluation, Preclinical; HMGB1 Protein; Inflammation; Janus Kinase 2; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Pyrazoles; Pyrimidines; RAW 264.7 Cells; Respiration, Artificial; STAT1 Transcription Factor; Ventilator-Induced Lung Injury

Lung cancer patients with mutations in epidermal growth factor receptor (EGFR) benefit from treatments targeting tyrosine kinase inhibitors (TKIs). However, both intrinsic and acquired resistance of tumors to TKIs are common, and EGFR variants have been identified that are resistant to multiple TKIs. In the present study, we characterized selected EGFR variants previously observed in lung cancer patients and expressed in a murine bone marrow pro-B Ba/F3 cell model. Among these EGFR variants, we report that an exon 20 deletion/insertion mutation S768insVGH is resistant to erlotinib (a first-generation TKI), but sensitive to osimertinib (a third-generation TKI). We also characterized a rare exon 21 germline variant, EGFR P848L, which transformed Ba/F3 cells and conferred resistance to multiple EGFR-targeting TKIs. Our analysis revealed that P848L (a) does not bind erlotinib; (b) is turned over less rapidly than L858R (a common tumor-derived EGFR mutation); (c) is not autophosphorylated at Tyr 1045 [the major docking site for Cbl proto-oncogene (c-Cbl) binding]; and (d) does not bind c-Cbl. Using viability assays including 300 clinically relevant targeted compounds, we observed that Ba/F3 cells transduced with EGFR P848L, S768insVGH, or L858R have very different drug-sensitivity profiles. In particular, EGFR P848L, but not L858R or S768insVGH, was sensitive to multiple Janus kinase 1/2 inhibitors. In contrast, cells driven by L858R, but not by P848L, were sensitive to multikinase MAPK/extracellular-signal-regulated kinase (ERK) kinase and ERK inhibitors including EGFR-specific TKIs. These observations suggest that continued investigation of rare TKI-resistant EGFR variants is warranted to identify optimal treatments for cancer.

Topics: Animals; Cell Proliferation; Cell Survival; Cells, Cultured; Disease Models, Animal; ErbB Receptors; Genetic Variation; HEK293 Cells; Humans; Lung Neoplasms; Mice; Mice, Transgenic; Microscopy, Fluorescence; Mutation; Nitriles; Protein Kinase Inhibitors; Proto-Oncogene Mas; Pyrazoles; Pyrimidines

Inflammatory modulation mediated by microglial M1/M2 polarization is one of the main pathophysiological processes involved in early brain injury (EBI) after subarachnoid haemorrhage (SAH). Previous studies have shown that recombinant human erythropoietin (rhEPO) alleviates EBI following experimental SAH. However, the mechanisms of this beneficial effect are still poorly understood. Recent research has suggested that EPO shows anti-inflammatory properties. Therefore, we tried to analyse whether rhEPO administration influenced microglial M1/M2 polarization in early brain injury after SAH and to identify the underlying molecular mechanism of any such effect. We found that treatment with rhEPO markedly ameliorated SAH-induced EBI, as shown by reductions in brain cell apoptosis, neuronal necrosis, albumin exudation and brain edema. Moreover, the expression levels of p-JAK2 and p-STAT3 were significantly increased in the cortex after SAH induction and were further increased by EPO treatment; in addition, the p-JAK2 inhibitor AZD1480 impaired the protective effect of EPO against SAH-induced EBI in vivo. Furthermore, EPO promoted the polarization of microglia towards the protective M2 phenotype and alleviated inflammation. In cultured microglia under oxyhemoglobin (OxyHb) treatment, EPO up-regulated the expression of the EPO receptor (EPOR), which did not occur in response to OxyHb treatment alone, and EPO magnified OxyHb-induced increases in p-JAK2 and p-STAT3 and modulated OxyHb-challenged microglial polarization towards M2. Interestingly, the effect of EPO on microglia polarization was cancelled by EPOR knockdown or by p-JAK2 or p-STAT3 inhibition, suggesting a core role of the EPOR/JAK2/STAT3 pathway in modulating microglial function and phenotype. In conclusion, the therapeutic effect of rhEPO on the early brain injury after SAH may relate to its modulation of inflammatory response and microglia M1/M2 polarization, which may be mediated in part by the EPOR/JAK2/STAT3 signalling pathway. These results improved the understanding of the anti-inflammatory effect of EPO on microglia polarization, which might optimize the therapeutic modalities of EPO treatment with SAH.

Topics: Animals; Anti-Inflammatory Agents; Brain Edema; Cell Differentiation; Cell Line; Cerebral Cortex; Disease Models, Animal; Erythropoietin; Gene Expression Regulation; Humans; Injections, Intraventricular; Janus Kinase 2; Mice; Mice, Inbred C57BL; Microglia; Neurons; Oxyhemoglobins; Pyrazoles; Pyrimidines; Receptors, Erythropoietin; Recombinant Proteins; Signal Transduction; STAT3 Transcription Factor; Stereotaxic Techniques; Subarachnoid Hemorrhage

Overcoming drug resistance is one of the greatest challenges in the treatment of multiple myeloma (MM). The interaction of myeloma cells with the bone marrow (BM) microenvironment is a major factor contributing to drug resistance. Tumour-associated macrophages (TAMs) with different polarization states constitute an important component of this microenvironment. Previous studies have revealed a role of TAMs in MM cell survival and drug resistance; however, the impact of macrophage polarization (anti-tumoural 'M1' versus pro-tumoural 'M2'-like phenotype) in this process has not yet been described. Here, the presence of TAMs was confirmed in BM sections from MM patients, both at diagnosis and relapse, with two M2 markers, CD163 and CD206. By following different TAM subpopulations during disease progression in the syngeneic murine 5T33MM model, we demonstrated a decrease in the number of inflammatory monocytes and an increase in the number of M2-oriented TAMs in BM. Co-culture experiments demonstrated that macrophages provide a survival benefit to myeloma cells that is maintained after treatment with several classes of anti-myeloma agent (melphalan and bortezomib); the greatest effect was observed with M2-polarized macrophages. The pro-survival effect was associated with activation of the STAT3 pathway in 5T33MM cells, less cleavage of caspase-3, and thus less apoptosis. AZD1480, an ATP-competitive JAK2 inhibitor, abrogated the observed TAM-mediated MM cell survival, and partially inhibited resistance to bortezomib. Despite having only a small quantitative impact on myeloid cells in vivo, AZD1480 treatment alone and in combination with bortezomib significantly reduced tumour load. In conclusion, M2 TAMs are present in the MM microenvironment, and contribute to MM cell survival and protection from drug-induced apoptosis. As a result of TAM-induced activation of the STAT3 pathway, 5T33MM cells are sensitized to AZD1480 treatment. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Antineoplastic Agents; Apoptosis; Biomarkers, Tumor; Bortezomib; Disease Models, Animal; Female; Humans; Macrophage Activation; Macrophages; Male; Mice; Mice, Inbred C57BL; Middle Aged; Multiple Myeloma; Myeloid Cells; Pyrazoles; Pyrimidines; STAT3 Transcription Factor; Tumor Microenvironment; Young Adult

Ovarian carcinoma is the fifth leading cause of death among women in the United States. Persistent activation of STAT3 is frequently detected in ovarian carcinoma. STAT3 is activated by Janus family kinases (JAK) via cytokine receptors, growth factor receptor, and non-growth factor receptor tyrosine kinases. Activation of STAT3 mediates tumor cell proliferation, survival, motility, invasion, and angiogenesis, and recent work demonstrates that STAT3 activation suppresses antitumor immune responses and supports tumor-promoting inflammation. We hypothesized that therapeutic targeting of the JAK/STAT3 pathway would inhibit tumor growth by direct effects on ovarian carcinoma cells and by inhibition of cells in the tumor microenvironment (TME). To test this, we evaluated the effects of a small-molecule JAK inhibitor, AZD1480, on cell viability, apoptosis, proliferation, migration, and adhesion of ovarian carcinoma cells in vitro. We then evaluated the effects of AZD1480 on in vivo tumor growth and progression, gene expression, tumor-associated matrix metalloproteinase (MMP) activity, and immune cell populations in a transgenic mouse model of ovarian carcinoma. AZD1480 treatment inhibited STAT3 phosphorylation and DNA binding, and migration and adhesion of cultured ovarian carcinoma cells and ovarian tumor growth rate, volume, and ascites production in mice. In addition, drug treatment led to altered gene expression, decreased tumor-associated MMP activity, and fewer suppressor T cells in the peritoneal TME of tumor-bearing mice than control mice. Taken together, our results show pharmacologic inhibition of the JAK2/STAT3 pathway leads to disruption of functions essential for ovarian tumor growth and progression and represents a promising therapeutic strategy.

Topics: Analgesics; Animals; Apoptosis; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Cluster Analysis; Disease Models, Animal; Female; Gene Expression; Gene Expression Profiling; Humans; Integrin alphaVbeta3; Janus Kinases; Matrix Metalloproteinases; Mice; Mice, Transgenic; Ovarian Neoplasms; Pyrazoles; Pyrimidines; Signal Transduction; STAT3 Transcription Factor; Xenograft Model Antitumor Assays

Aberrant activation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) 3 has been implicated in cell proliferation and survival of many cancers including head and neck squamous cell carcinoma (HNSCC). AZD1480, an orally active pharmacologic inhibitor of JAK1/JAK2, has been tested in several cancer models. In the present study, the in vitro and in vivo effects of AZD1480 were evaluated in HNSCC preclinical models to test the potential use of JAK kinase inhibition for HNSCC therapy. AZD1480 treatment decreased HNSCC proliferation in HNSCC cell lines with half maximal effective concentration (EC50) values ranging from 0.9 to 4 μM in conjunction with reduction of pSTAT3(Tyr705) expression. In vivo antitumor efficacy of AZD1480 was demonstrated in patient-derived xenograft (PDX) models derived from two independent HNSCC tumors. Oral administration of AZD1480 reduced tumor growth in conjunction with decreased pSTAT3(Tyr705) expression that was observed in both PDX models. These findings suggest that the JAK1/2 inhibitors abrogate STAT3 signaling and may be effective in HNSCC treatment approaches.

Topics: Animals; Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Gene Dosage; Gene Expression; Head and Neck Neoplasms; Humans; Janus Kinase 1; Janus Kinase 2; Janus Kinases; Mice; Phosphorylation; Protein Kinase Inhibitors; Pyrazoles; Pyrimidines; RNA, Messenger; Signal Transduction; Squamous Cell Carcinoma of Head and Neck; STAT3 Transcription Factor; Tumor Burden; Xenograft Model Antitumor Assays

Metastatic prostate cancer is lethal and lacks effective strategies for prevention or treatment, requiring novel therapeutic approaches. Interleukin-6 (IL-6) is a cytokine that has been linked with prostate cancer pathogenesis by multiple studies. However, the direct functional roles of IL-6 in prostate cancer growth and progression have been unclear. In the present study, we show that IL-6 is produced in distant metastases of clinical prostate cancers. IL-6-activated signaling pathways in prostate cancer cells induced a robust 7-fold increase in metastases formation in nude mice. We further show that IL-6 promoted migratory prostate cancer cell phenotype, including increased prostate cancer cell migration, microtubule reorganization, and heterotypic adhesion of prostate cancer cells to endothelial cells. IL-6-driven metastasis was predominantly mediated by Stat3 and to lesser extent by ERK1/2. Most importantly, pharmacologic inhibition of Jak1/2 by AZD1480 suppressed IL-6-induced signaling, migratory prostate cancer cell phenotypes, and metastatic dissemination of prostate cancer in vivo in nude mice. In conclusion, we demonstrate that the cytokine IL-6 directly promotes prostate cancer metastasis in vitro and in vivo via Jak-Stat3 signaling pathway, and that IL-6-driven metastasis can be effectively suppressed by pharmacologic targeting of Jak1/2 using Jak1/2 inhibitor AZD1480. Our results therefore provide a strong rationale for further development of Jak1/2 inhibitors as therapy for metastatic prostate cancer.

Topics: Animals; Cell Adhesion; Cell Line, Tumor; Cell Movement; Disease Models, Animal; Gene Expression; Humans; Interleukin-6; Janus Kinase 1; Janus Kinase 2; Male; MAP Kinase Signaling System; Mice; Mice, Nude; Neoplasm Metastasis; Phenotype; Prostatic Neoplasms; Pyrazoles; Pyrimidines; STAT3 Transcription Factor

Acute myeloid leukemia (AML) is sustained by small populations of leukemia stem cells (LSCs) that can resist available treatments and represent important barriers to cure. Although previous studies have shown increased signal transducer and activator of transcription (STAT)3 and STAT5 phosphorylation in AML leukemic blasts, the role of Janus kinase (JAK) signaling in primary AML compared with normal stem cells has not been directly evaluated. We show here that JAK/STAT signaling is increased in LSCs, particularly from high-risk AML. JAK2 inhibition using small molecule inhibitors or interference RNA reduced growth of AML LSCs while sparing normal stem cells both in vitro and in vivo. Increased JAK/STAT activity was associated with increased expression and altered signaling through growth factor receptors in AML LSCs, including receptor tyrosine kinase c-KIT and FMS-related tyrosine kinase 3 (FLT3). Inhibition of c-KIT and FLT3 expression significantly inhibited JAK/STAT signaling in AML LSCs, and JAK inhibitors effectively inhibited FLT3-mutated AML LSCs. Our results indicate that JAK/STAT signaling represents an important signaling mechanism supporting AML LSC growth and survival. These studies support continued evaluation of strategies for JAK/STAT inhibition for therapeutic targeting of AML LSCs.

Topics: Animals; Antigens, CD34; Cell Proliferation; Cell Survival; Disease Models, Animal; Female; Gene Expression Regulation, Leukemic; Humans; Janus Kinase 2; Janus Kinases; Leukemia, Myeloid, Acute; Mice; Neoplastic Stem Cells; Phenotype; Phosphorylation; Pyrazoles; Pyrimidines; Receptors, Growth Factor; RNA Interference; Signal Transduction; STAT Transcription Factors; STAT3 Transcription Factor; STAT5 Transcription Factor; Xenograft Model Antitumor Assays

AZD1480 is a potent, competitive small-molecule inhibitor of JAK1/2 kinase which inhibits STAT3 phosphorylation and tumor growth. Here we investigated the effects of AZD1480 on the function of different immune cell populations in a melanoma model. When MO4 tumor-bearing mice were treated with AZD1480 we observed a strong inhibition of tumor growth as well as a prolonged survival. Moreover, a significant decrease in the percentage of myeloid-derived suppressor cells (MDSCs) was observed after treatment with AZD1480. However, AZD1480 enhanced the suppressive capacity of murine MDSCs while at the same time impairing the proliferative as well as the IFN-γ secretion capacity of murine T cells. The addition of AZD1480 to co-cultures of human MDSCs and T cells does not affect the suppressive activity of MDSCs but it does reduce the IFN-γ secretion and the proliferative capacity of T cells. We showed that although AZD1480 has the ability to delay the tumor growth of MO4 tumor-bearing mice, this drug has detrimental effects on several aspects of the immune system. These data indicate that systemic targeting of the JAK/STAT pathway by JAK1/2 inhibition can have divergent effects on tumor growth and anti-tumor immune responses.

Topics: Animals; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Female; Humans; Janus Kinase 2; Melanoma; Melanoma, Experimental; Mice; Mice, Inbred C57BL; Myeloid Cells; Pyrazoles; Pyrimidines; Random Allocation; Signal Transduction; Xenograft Model Antitumor Assays

We have recently reported that interferon gamma receptor deficient (IFNγR-/-) allogeneic donor T cells result in significantly less graft-versus-host disease (GvHD) than wild-type (WT) T cells, while maintaining an anti-leukemia or graft-versus-leukemia (GvL) effect after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We demonstrated that IFNγR signaling regulates alloreactive T cell trafficking to GvHD target organs through expression of the chemokine receptor CXCR3 in alloreactive T cells. Since IFNγR signaling is mediated via JAK1/JAK2, we tested the effect of JAK1/JAK2 inhibition on GvHD. While we demonstrated that pharmacologic blockade of JAK1/JAK2 in WT T cells using the JAK1/JAK2 inhibitor, INCB018424 (Ruxolitinib), resulted in a similar effect to IFNγR-/- T cells both in vitro (reduction of CXCR3 expression in T cells) and in vivo (mitigation of GvHD after allo-HSCT), it remains to be determined if in vivo administration of INCB018424 will result in preservation of GvL while reducing GvHD. Here, we report that INCB018424 reduces GvHD and preserves the beneficial GvL effect in two different murine MHC-mismatched allo-HSCT models and using two different murine leukemia models (lymphoid leukemia and myeloid leukemia). In addition, prolonged administration of INCB018424 further improves survival after allo-HSCT and is superior to other JAK1/JAK2 inhibitors, such as TG101348 or AZD1480. These data suggest that pharmacologic inhibition of JAK1/JAK2 might be a promising therapeutic approach to achieve the beneficial anti-leukemia effect and overcome HLA-barriers in allo-HSCT. It might also be exploited in other diseases besides GvHD, such as organ transplant rejection, chronic inflammatory diseases and autoimmune diseases.

Topics: Animals; Disease Models, Animal; Gene Expression Regulation, Leukemic; Graft vs Host Disease; Graft vs Leukemia Effect; Hematopoietic Stem Cell Transplantation; Interferon gamma Receptor; Janus Kinase 1; Janus Kinase 2; Leukemia, Lymphoid; Leukemia, Myeloid; Mice; Mice, Inbred BALB C; Mice, Knockout; Nitriles; Protein Kinase Inhibitors; Pyrazoles; Pyrimidines; Pyrrolidines; Receptors, Interferon; Signal Transduction; Sulfonamides; T-Lymphocytes; Transplantation, Homologous; Whole-Body Irradiation

Progression of prostate cancer to the lethal castrate-resistant stage coincides with loss of responsiveness to androgen deprivation and requires development of novel therapies. We previously provided proof-of-concept that Stat5a/b is a therapeutic target protein for prostate cancer. Here, we show that pharmacologic targeting of Jak2-dependent Stat5a/b signaling by the Jak2 inhibitor AZD1480 blocks castrate-resistant growth of prostate cancer.. Efficacy of AZD1480 in disrupting Jak2-Stat5a/b signaling and decreasing prostate cancer cell viability was evaluated in prostate cancer cells. A unique prostate cancer xenograft mouse model (CWR22Pc), which mimics prostate cancer clinical progression in patients, was used to assess in vivo responsiveness of primary and castrate-resistant prostate cancer (CRPC) to AZD1480. Patient-derived clinical prostate cancers, grown ex vivo in organ explant cultures, were tested for responsiveness to AZD1480.. AZD1480 robustly inhibited Stat5a/b phosphorylation, dimerization, nuclear translocation, DNA binding, and transcriptional activity in prostate cancer cells. AZD1480 reduced prostate cancer cell viability sustained by Jak2-Stat5a/b signaling through induction of apoptosis, which was rescued by constitutively active Stat5a/b. In mice, pharmacologic targeting of Stat5a/b by AZD1480 potently blocked growth of primary androgen-dependent as well as recurrent castrate-resistant CWR22Pc xenograft tumors, and prolonged survival of tumor-bearing mice versus vehicle or docetaxel-treated mice. Finally, nine of 12 clinical prostate cancers responded to AZD1480 by extensive apoptotic epithelial cell loss, concurrent with reduced levels of nuclear Stat5a/b.. We report the first evidence for efficacy of pharmacologic targeting of Stat5a/b as a strategy to inhibit castrate-resistant growth of prostate cancer, supporting further clinical development of Stat5a/b inhibitors as therapy for advanced prostate cancer.

Topics: Aged; Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Survival; Disease Models, Animal; Humans; Janus Kinase 2; Male; Mice; Middle Aged; Neoplasm Grading; Neoplasm Metastasis; Neoplasm Staging; Orchiectomy; Phosphorylation; Prostatic Neoplasms; Protein Binding; Protein Multimerization; Protein Transport; Pyrazoles; Pyrimidines; Receptors, Androgen; Signal Transduction; STAT3 Transcription Factor; STAT5 Transcription Factor; Transcriptional Activation; Tumor Burden; Xenograft Model Antitumor Assays

Determining the mechanism of treatment failure of VEGF signaling inhibitors for malignant glioma patients would provide insight into approaches to overcome therapeutic resistance. In this study, we demonstrate that human glioblastoma tumors failing bevacizumab have an increase in the mean percentage of p-STAT3-expressing cells compared to samples taken from patients failing non-antiangiogenic therapy containing regimens. Likewise, in murine xenograft models of glioblastoma, the mean percentage of p-STAT3-expressing cells in the gliomas resistant to antiangiogenic therapy was markedly elevated relative to controls. Administration of the JAK/STAT3 inhibitor AZD1480 alone and in combination with cediranib reduced tumor hypoxia and the infiltration of VEGF inhibitor-induced p-STAT3 macrophages. Thus, the combination of AZD1480 with cediranib markedly reduced tumor volume, and microvascular density, indicating that up regulation of the STAT3 pathway can mediate resistance to antiangiogenic therapy and combinational approaches may delay or overcome resistance.

Topics: Angiogenesis Inhibitors; Animals; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Brain Neoplasms; Cell Hypoxia; Cell Line, Tumor; Disease Models, Animal; Drug Interactions; Female; Glioblastoma; Humans; Immunohistochemistry; Intermediate Filament Proteins; Macrophages; Mice; Mice, Inbred C57BL; Mice, Nude; Nerve Tissue Proteins; Nestin; Pyrazoles; Pyrimidines; Quinazolines; Signal Transduction; STAT3 Transcription Factor; Xenograft Model Antitumor Assays