Ruxolitinib for the treatment of acute graft-versus-host disease: a retrospective analysis.

Steroid-refractory acute graft-versus-host disease (aGvHD) is a serious complication after allogeneic hematopoietic stem cell transplantation, associated with significant mortality. Ruxolitinib was the first drug approved for aGvHD, based on results of the REACH2 trial; however, real-world data are limited. We retrospectively analyzed the safety and efficacy of ruxolitinib for treatment of aGvHD at our center from March 2016 to August 2022 and assessed biomarkers of risk. We identified 49 patients receiving ruxolitinib as second- (33/49), third- (11/49), fourth- (3/49), or fifth-line (2/49) treatment. Ruxolitinib was started on median day 11 (range, 7-21) after aGvHD onset; median duration of administration was 37 days (range, 20-86), with 10 patients continuing treatment at last follow-up. Median follow-up period was 501 days (range, 95-905). In the primary analysis at the 1-month assessment, overall response rate was 65%, and failure-free survival was 78%. Infectious complications ≥ CTCAE Grade III were observed in 10/49 patients within 1-month followup. Patients responding to ruxolitinib therapy required fewer steroids and exhibited lower levels of the serum biomarkers regenerating islet-derived protein 3-alpha, suppression of tumorigenicity 2, and the Mount Sinai Acute GVHD International Consortium algorithm probability. A univariate regression model revealed steroid-dependent aGvHD as a significant predictor of better response to ruxolitinib. Within 6-months follow-up, four patients experienced recurrence of underlying malignancy, and eight died due to treatment-related mortality. Overall, ruxolitinib was welltolerated and showed response in heavily pretreated patients, with results comparable to those of the REACH2 trial. Biomarkers may be useful predictors of response to ruxolitinib.

Efficacy and safety of ruxolitinib in the treatment of chronic graft-versus-host disease: a retrospective analysis.

Steroid-refractory chronic graft-versus-host disease (cGvHD) is associated with significant morbidity and mortality, with ruxolitinib being the first drug approved for its treatment. We retrospectively analyzed the safety and efficacy of ruxolitinib for treatment of cGvHD at our center between 07/2015 and 12/2022 and identified 48 patients receiving ruxolitinib as second (18/48) or advanced (30/48) treatment line. Ruxolitinib was started on median day 340 (range 119-595) after cGvHD onset; median duration of administration was 176 (range, 79-294) days with 16/48 patients continuing treatment at last follow-up. National Institutes of Health organ grading and the intensity of immunosuppression were assessed at the start of ruxolitinib treatment and repeated after 1, 3, 6, and 12 months. Response assessment was terminated at the start of any additional new immunosuppressant treatment. The median time of follow-up was 582 (range, 104-1161) days. At the primary analysis after six months on ruxolitinib treatment, the overall response rate was 33%, and failure-free survival was 58%. Infectious adverse events ≥ CTCAE grade III were observed in 10/48 patients. The response rate was not associated with the severity of cGvHD, number of previous treatment lines, or number of additional agents combined with ruxolitinib applying a univariate regression model. At the time of the 12-month follow-up, four patients experienced recurrence of the underlying malignancy and two patients had experienced non-relapse-related mortality. Overall, ruxolitinib was relatively well-tolerated and showed outcomes comparable to the REACH3 trial in a heavily pretreated patient population.

Systemic Lupus Erythematosus and Cytokine Storm.

Systemic lupus erythematosus (SLE) is the prototype of autoimmune diseases and can manifest with a plethora of clinical signs and symptoms associated with a myriad of laboratory abnormalities. An infrequent but potentially lethal complication of SLE is macrophage activation syndrome (MAS). The diagnosis of MAS in SLE can be very challenging due to similarities in presentation of both flares and infections, such as fever, lymphadenopathy, splenomegaly, and cytopenias. These aggravating factors contribute to the increased risk of poor outcomes in SLE-associated MAS. Indeed, at the moment MAS remains invariably lethal if untreated and still has a high mortality rate with treatment. In this chapter, we discuss several aspects of MAS in the context of SLE and in particular, the pathogenesis of MAS in SLE, how MAS presents in pediatric versus adult SLE, and, finally, MAS treatment in SLE and future directions.

Real-world analysis of ruxolitinib in myelofibrosis: interim results focusing on patients who were naïve to JAK inhibitor therapy treated within the JAKoMo non-interventional, phase IV trial.

Ruxolitinib (RUX) is a Janus kinase 1/2 inhibitor (JAKi) approved in the EU for treating disease­related splenomegaly or symptoms in adults patients with myelofibrosis (MF). This is an interim analysis of JAKoMo, a prospective, non­interventional, phase IV study in MF. Between 2012-2019 (cutoff March 2021), 928 patients (JAKi-naïve and -pretreated) enrolled from 122 German centers. This analysis focuses on JAKi-naïve patients. RUX was administered according to the Summary of Product Characteristics. Compared to the COMFORT-I, -II, and JUMP trials, patients in JAKoMo were older (median 73 years), had poorer Eastern Cooperative Oncology Group (ECOG) performance statuses (16.5% had ECOG ≥ 2), and were more transfusion dependent (48.5%). JAKoMo represents the more challenging patients with MF encountered outside of interventional studies. However, patients with low-risk International Prognostic Scoring System (IPSS) scores or without palpable splenomegaly were also included. Following RUX treatment, 82.5% of patients experienced rapid (≤ 1 month), significant decreases in palpable spleen size, which remained durable for 24 months (60% patients). Symptom assessment scores improved significantly in Month 1 (median -5.2) up to Month 12 (-6.2). Common adverse events (AEs) were anemia (31.2%) and thrombocytopenia (28.6%). At cutoff, 54.3% of patients had terminated the study due to, death, AEs, or deterioration of health. No new safety signals were observed. Interim analysis of the JAKoMo study confirms RUX safety and efficacy in a representative cohort of real-world, elderly, JAKi-naïve patients with MF. Risk scores were used in less than half of the patients to initiate RUX treatment.Trial registration: NCT05044026; September 14, 2021.

Interferon gamma regulates a complex pro-survival signal network in chronic lymphocytic leukemia.

BACKGROUND: It is known that the microenvironmental cytokine interferon gamma (IFN-γ) provides a survival advantage for chronic lymphocytic leukemia (CLL) cells. However, the mechanisms involved in this effect have not been properly investigated. METHODS: Herein, we conducted a comprehensive screening of the effects of IFN-γ on signaling pathways and gene expression profiles in CLL cells by using western blotting, real-time quantitative reverse transcription (RT-qPCR) and high-throughput RNA sequencing (RNA-seq). RESULTS: We found that IFN-γ not only activated the pro-survival signal transducer and activator of transcription 3 (STAT3), but also activated the protein kinase B and extracellular signal-regulated kinase signaling pathways. RNA-seq analysis showed that IFN-γ stimulation changed the expression profiles of more than 500 genes, with 391 being up-regulated and 123 down-regulated. These genes are involved in numerous biological processes, including anti-apoptosis, cell migration, and proliferation. IFN-γ significantly up-regulated the expression of CD38, BCL6, CXCL9, BCL2A1, SCOS3, IL-10, HGF, EGFR, THBS-1, FN1, and MUC1, which encode proteins potentially associated with disease progression, worse prognosis or poor response to treatment. Blocking janus kinases1/2 (JAK1/2) or STAT3 signal by specific inhibitors affected the expression of most genes, suggesting a pivotal role of the JAK1/2-STAT3 pathway in IFN-γ pro-survival effects in CLL. CONCLUSIONS: Our data demonstrate that IFN-γ regulates a complex pro-survival signal network in CLL through JAK1/2-STAT3, which provides a rational explanation for IFN-γ promoting CLL cells survival and drug resistance.

EPN3 plays oncogenic role in non-small cell lung cancer by activating the JAK1/2-STAT3 pathway.

The effect of Epsin 3 (EPN3) on non-small cell lung cancer (NSCLC) has not yet been clearly elucidated. This study identified the exact function of EPN3 on NSCLC progression. EPN3 expression in NSCLC patients were analyzed based on the Cancer Genome Atlas database. Kaplan-Meier analysis was implemented to research the effect of EPN3 on patients' survival. EPN3 expression in clinical tissues of 62 NSCLC cases was monitored by real-time quantitative reverse transcription polymerase chain reaction, immunohistochemistry and Western blot. A549 and H1299 cells were transfected with EPN3 shRNA and treated by RO8191 (20 µM). Proliferation was researched by cell counting kit-8 and 5-ethnyl-2 deoxyuridine assays. Apoptosis was monitored by flow cytometry. Migration and invasion was assessed by Transwell experiment. EPN3 effect on A549 cell in vivo growth was researched using nude mice. RO8191 (200 µg) was intratumoral injected into mice. Immunohistochemistry and Western blot was implemented to monitor protein expression in cells and xenograft tumor tissues. EPN3 was abnormally up-regulated in NSCLC patients and cells, indicating a lower overall survival. Loss of EPN3 weakened proliferation, migration and invasion, induced apoptosis, and repressed epithelial-mesenchymal transition in NSCLC cells. Loss of EPN3 inactivated the JAK1/2-STAT3 pathway in NSCLC cells. RO8191 treatment reversed the inhibition of EPN3 knockdown on the malignant phenotype of NSCLC cells. RO8191 intratumoral injection reversed the suppression of EPN3 silencing on NSCLC cell in vivo growth. EPN3 acted as an oncogene in NSCLC via activating the JAK1/2-STAT3 pathway. EPN3 may be a promising target for NSCLC treatment.

Design and synthesis of the 4H-chromenone derivatives against psoriasis.

On basis of Quercetin moiety, two series of 20 new compounds were designed and synthesized accordingly in this study, and their anti-inflammatory activities in vitro and in vivo were evaluated. At last, compound 8A2: 3- (1- (2- (4- (5-bromo-2-chlorobenzoyl) piperazin-1-yl) ethyl)-1H-1,2,3-triazol-4-yl) methoxy)-5,7-dimethoxy-2-(3,4,5-trimethoxyphenyl)-4H-chromen-4-one with low toxicity was found the best one for inhibiting of NO. Meanwhile, this compound could significantly inhibit the expression of IL-6 (Interleukin-6), TNF-α (Tumor necrosis factor-α) and IL-17 (Interleukin-17), and also significantly down-regulate IL-17 mRNA psoriasis model in vitro. Further studies were performed to establish mouse psoriasis model induced by Imiquimod (IMQ), and the preliminary mechanism indicated that compound 8A2 may alleviate mouse psoriasis through obstructed the JAK1/2-STAT1/3 pathway. This study should be provide a basis for further study of effective treatment of psoriasis.

GRP78 facilitates M2 macrophage polarization and tumour progression.

This study investigated the regulation of GRP78 in tumour-associated macrophage polarization in lung cancer. First, our results showed that GRP78 was upregulated in macrophages during M2 polarization and in a conditioned medium derived from lung cancer cells. Next, we found that knocking down GRP78 in macrophages promoted M1 differentiation and suppressed M2 polarization via the Janus kinase/signal transducer and activator of transcription signalling. Moreover, conditioned medium from GRP78- or insulin-like growth factor 1-knockdown macrophages attenuated the survival, proliferation, and migration of lung cancer cells, while conditioned medium from GRP78-overexpressing macrophages had the opposite effects. Additionally, GRP78 knockdown reduced both the secretion of insulin-like growth factor 1 and the phosphorylation of the insulin-like growth factor 1 receptor. Interestingly, insulin-like growth factor 1 neutralization downregulated GRP78 and suppressed GRP78 overexpression-induced M2 polarization. Mechanistically, insulin-like growth factor 1 treatment induced the translocation of GRP78 to the plasma membrane and promoted its association with the insulin-like growth factor 1 receptor. Finally, IGF-1 blockade and knockdown as well as GRP78 knockdown in macrophages inhibited M2 macrophage-induced survival, proliferation, and migration of lung cancer cells both in vitro and in vivo.

[Maxing Shigan Decoction improves lung and colon tissue damage caused by influenza virus infection through JAK1/2-STAT1 signaling pathway].

Based on Janus kinase 1/2-signal transducer and activator of transcription 1(JAK1/2-STAT1) signaling pathway, this study explored the immune mechanism of Maxing Shigan Decoction in alleviating the lung tissue and colon tissue damage in mice infected with influenza virus. The influenza virus infection was induced in mice by nasal drip of influenza virus. The normal group, model group, oseltamivir group, antiviral granule group, and Maxing Shigan Decoction group were designed. After intragastric administration of corresponding drugs or normal saline for 3 or 7 days, the body mass was measured, and lung index, spleen index, and thymus index were calculated. Based on hematoxylin-eosin(HE) staining, the pathological changes of lung tissue and colon tissue were observed. Enzyme-linked immunosorbent assay(ELISA) was used to detect serum levels of inflammatory factors interleukin-8(IL-8) and interferon-γ(IFN-γ), Western blot and real-time quantitative polymerase chain reaction(RT-qPCR) to determine the protein and mRNA levels of JAK1, JAK2, STAT1, interferon regulatory factor 9(IRF9), and IFN-γ in lung tissue and colon tissue. The results showed that after 3 and 7 days of administration, the body mass, spleen index, and thymus index were lower(P<0.05 or P<0.01), and the lung index was higher(P<0.01) in the model group than in the normal group. Moreover, the model group showed congestion, edema, and infiltration of a large number of lymphocytes and macrophages in the lung tissue, irregular structure of colon mucosa, ulceration and shedding of epithelial cells, and infiltration of a large number of inflammatory cells. The model group had higher levels of serum IFN-γ(P<0.01), higher protein and mRNA expression of JAK1, JAK2, STAT1, IRF9, IFN-γ in lung tissue(P<0.05 or P<0.01), higher level of JAK2 protein in colon tissue(P<0.01), and higher protein and mRNA levels of STAT1 and IRF9(P<0.05 or P<0.01) than the normal group. Compared with the model group, Maxing Shigan Decoction group had high body mass, spleen index, and thymus index(P<0.05 or P<0.01), low lung index(P<0.05 or P<0.01), and significant alleviation of pathological injury in lung and colon. Moreover, lower serum level of IFN-γ(P<0.05 or P<0.01), protein and mRNA levels of JAK1, JAK2, STAT1, IRF9, and IFN-γ in lung tissue(P<0.05 or P<0.01), JAK2 protein level in colon tissue(P<0.01), and protein and mRNA levels of STAT1 and IRF9(P<0.05 or P<0.01) were observed in the Maxing Shigan Decoction group than in the model group. After 3 days of administration, the level of serum IL-8 in the model group was significantly higher than that in the normal group(P<0.01), and the level in the Maxing Shigan Decoction group was significantly reduced(P<0.01). In conclusion, Maxing Shigan Decoction can significantly up-regulate body mass, spleen index, and thymus index, down-regulate lung index, reduce the levels of IL-8 and IFN-γ, and down-regulate protein and mRNA levels of JAK1, JAK2, STAT1, IRF9, and IFN-γ in lung tissue and protein and mRNA levels of JAK2, STAT1, and IRF9 in colon tissue, and alleviate pathological damage of lung tissue and colon tissue. The mechanism is the likelihood that it inhibits the activation of JAK1/2-STAT1 signaling pathway to alleviate the damage to lung and colon tissue damage.

Ruxolitinib reverses checkpoint inhibition by reducing programmed cell death ligand-1 (PD-L1) expression and increases anti-tumour effects of T cells in multiple myeloma.

Multiple myeloma (MM) tumour cells evade host immunity through a variety of mechanisms, which may potentially include the programmed cell death ligand-1 (PD-L1):programmed cell death protein-1 (PD-1) axis. This interaction contributes to the immunosuppressive bone marrow (BM) microenvironment, ultimately leading to reduced effector cell function. PD-L1 is overexpressed in MMBM and is associated with the resistance to immune-based approaches for treating MM. Ruxolitinib (RUX), an inhibitor of the Janus kinase (JAK) family of protein tyrosine kinases, is approved for myeloproliferative diseases. We investigated the effects of RUX alone or in combination with anti-MM agents on the expression of PD-L1 and T-cell cytotoxicity in MM. We showed that the expression of the PD-L1 gene was markedly increased in BM mononuclear cells from patients with MM with progressive disease versus those in complete remission. Furthermore, RUX treatment resulted in a concentration-dependent reduction of PD-L1 gene expression in the MM tumour cells cultured alone or co-cultured with stromal cells compared with untreated cells. The results also demonstrated that RUX increased MM cell apoptosis in the presence of interleukin-2-stimulated T cells to a similar degree as the treatment with anti-PD-1 or anti-PD-L1 antibodies. In summary, these results indicate that RUX can block PD-L1 expression resulting in augmentation of anti-MM effects of T cells.

Citarinostat and Momelotinib co-target HDAC6 and JAK2/STAT3 in lymphoid malignant cell lines: a potential new therapeutic combination.

Histone deacetylase (HDAC) inhibitors represent an encouraging class of antitumor drugs. HDAC inhibitors induce a series of molecular and biological responses and minimal toxicity to normal cells. Citarinostat (Acy-241) is a second generation, orally administered, HDAC6-selective inhibitor. Momelotinib (CYT387) is an orally administered inhibitor of Janus kinase/signal transducer of transcription-3 (JAK/STAT3) signaling. Momelotinib showed efficacy in patients with myelofibrosis. We hypothesized that both HDAC and JAK/STAT pathways were important in lymphoproliferative disorders, and that inhibiting JAK/STAT3 and HDAC simultaneously might enhance the efficacy of momelotinib and citarinostat without increasing toxicity. Accordingly, we tested the citarinostat + momelotinib combination in lymphoid cell lines. Citarinostat + momelotinib showed strong cytotoxicity; it significantly reduced mitochondrial membrane potential, down-regulated Bcl-2 and Bcl-xL, and activated caspases 9 and 3. Caspase-8 was upregulated in only two lymphoid cell lines, which indicated activation of the extrinsic apoptotic pathway. We identified a lymphoid cell line that was only slightly sensitive to the combination treatment. We knocked down thioredoxin expression by transfecting with small interfering RNA that targeted thioredoxin. This knockdown increased cell sensitivity to the combination-induced cell death. The combination treatment reduced Bcl-2 expression, activated caspase 3, and significantly inhibited cell viability and clonogenic survival.

Myeloproliferative blood cancers as a human neuroinflammation model for development of Alzheimer's disease: evidences and perspectives.

Chronic inflammation and involvement of myeloid blood cells are associated with the development of Alzheimer's disease (AD). Chronic inflammation is a highly important driving force for the development and progression of the chronic myeloproliferative blood cancers (MPNs), which are characterized by repeated thrombotic episodes years before MPN-diagnosis, being elicited by elevated erythrocytes, leukocytes, and platelets. Mutations in blood cells, the JAK2V617F and TET2-mutations, contribute to the inflammatory and thrombogenic state. Herein, we discuss the MPNs as a human neuroinflammation model for AD development, taking into account the many shared cellular mechanisms for reduction in cerebral blood, including capillary stalling with plugging of blood cells in the cerebral microcirculation. The therapeutic consequences of an association between MPNs and AD are immense, including reduction in elevated cell counts by interferon-alpha2 or hydroxyurea and targeting the chronic inflammatory state by JAK1-2 inhibitors, e.g., ruxolitinib, in the future treatment of AD.

Discovery of triazolo [1,5-a] pyridine derivatives as novel JAK1/2 inhibitors.

Small molecule JAK inhibitors have been demonstrated efficacy in rheumatoid arthritis, inflammatory bowel disease, and psoriasis with the approval of several drugs. Aiming to develop potent JAK1/2 inhibitors, two series of triazolo [1,5-a] pyridine derivatives were designed and synthesized by various strategies. The pharmacological results identified the optimized compounds J-4 and J-6, which exerted high potency against JAK1/2, and selectivity over JAK3 in enzyme assays. Furthermore, J-4 and J-6 effectively suppressed proliferation of JAK1/2 high-expression BaF3 cells accompanied with acceptable metabolic stability in liver microsomes. Therefore, J-4 and J-6 might serve as promising JAK1/2 inhibitors for further investigation.

IL-6 stimulation of DNA replication is JAK1/2 mediated in cross-talk with hyperactivated ERK1/2 signaling.

Myeloproliferative neoplasms (MPNs) are developing resistance to therapy by JAK1/2 inhibitor ruxolitinib. To explore the mechanism of ruxolitinib's limited effect, we examined the JAK1/2 mediated induction of proliferation related ERK1/2 and AKT signaling by proinflammatory interleukin-6 (IL-6) in MPN granulocytes and JAK2V617F mutated human erythroleukemia (HEL) cells. We found that JAK1/2 or JAK2 inhibition prevented the IL-6 activation of STAT3 and AKT pathways in polycythemia vera and HEL cells. Further, we showed that these inhibitors also blocked the IL-6 activation of the AKT pathway in primary myelofibrosis (PMF). Only JAK1/2 inhibitor ruxolitinib largely activated ERK1/2 signaling in essential thrombocythemia and PMF (up to 4.6 fold), with a more prominent activation in JAK2V617F positive granulocytes. Regarding a cell cycle, we found that IL-6 reduction of HEL cells percentage in G2M phase was reversed by ruxolitinib (2.6 fold). Moreover, ruxolitinib potentiated apoptosis of PMF granulocytes (1.6 fold). Regarding DNA replication, we found that ruxolitinib prevented the IL-6 augmentation of MPN granulocytes frequency in the S phase of the cell cycle (up to 2.9 fold). The inflammatory stimulation induces a cross-talk between the proliferation linked pathways, where JAK1/2 inhibition is compensated by the activation of the ERK1/2 pathway during IL-6 stimulation of DNA replication.

Expression of pro-inflammatory cytokines and mediators induced by Bisphenol A via ERK-NFκB and JAK1/2-STAT3 pathways in macrophages.

Macrophages not only play an important role in the innate immune response but also participate in many inflammatory and infectious diseases including asthma, diabetes, obesity, cardiovascular diseases, and cancers. Bisphenol A (BPA) is the most commonly used component for plastic products. However, BPA is an endocrine disruptor for mammals and participates in several inflammatory and infectious diseases. Up until now, there are no researches demonstrated the potential role of BPA in macrophage activation and its relative mechanism. BPA promoted the generation of proinflammatory cytokines IL-1ß, IL-6, and TNFα in a concentration-dependent manner (P < 0.05). BPA was identified to increase the expression of proinflammatory mediators NO and PGE2, and its upstream factors iNOS, COX2, and cPLA2 in a concentration-dependent manner (P < 0.05). Phosphorylation and nuclear translocation of NF-κB p65 were significantly induced by BPA via IκB degradation (P < 0.05). In addition, phosphorylation of ERK significantly induced by BPA at a concentration which was less than that for phosphorylation of p38 MAPK and JNK (P < 0.05). Furthermore, phosphorylation of STAT3 significantly induced by BPA at a concentration lower than that for phosphorylation of STAT1 (P < 0.05). Phosphorylation of JAK1 and JAK2 was also significantly induced by BPA in a concentration-dependent manner (P < 0.05).

Outcomes of Allogeneic Hematopoietic Cell Transplantation in Patients with Myelofibrosis with Prior Exposure to Janus Kinase 1/2 Inhibitors.

The impact of Janus kinase (JAK) 1/2 inhibitor therapy before allogeneic hematopoietic cell transplantation (HCT) has not been studied in a large cohort in myelofibrosis (MF). In this retrospective multicenter study, we analyzed outcomes of patients who underwent HCT for MF with prior exposure to JAK1/2 inhibitors. One hundred consecutive patients from participating centers were analyzed, and based on clinical status and response to JAK1/2 inhibitors at the time of HCT, patients were stratified into 5 groups: (1) clinical improvement (n = 23), (2) stable disease (n = 31), (3) new cytopenia/increasing blasts/intolerance (n = 15), (4) progressive disease: splenomegaly (n = 18), and (5) progressive disease: leukemic transformation (LT) (n = 13). Overall survival (OS) at 2 years was 61% (95% confidence interval [CI], 49% to 71%). OS was 91% (95% CI, 69% to 98%) for those who experienced clinical improvement and 32% (95% CI, 8% to 59%) for those who developed LT on JAK1/2 inhibitors. In multivariable analysis, response to JAK1/2 inhibitors (P = .03), dynamic international prognostic scoring system score (P = .003), and donor type (P = .006) were independent predictors of survival. Among the 66 patients who remained on JAK1/2 inhibitors until stopped for HCT, 2 patients developed serious adverse events necessitating delay of HCT and another 8 patients had symptoms with lesser severity. Adverse events were more common in patients who started tapering or abruptly stopped their regular dose ≥6 days before conditioning therapy. We conclude that prior exposure to JAK1/2 inhibitors did not adversely affect post-transplantation outcomes. Our data suggest that JAK1/2 inhibitors should be continued near to the start of conditioning therapy. The favorable outcomes of patients who experienced clinical improvement with JAK1/2 inhibitor therapy before HCT were particularly encouraging, and need further prospective validation.

Initial solid tumor testing (stage 1) of AZD1480, an inhibitor of Janus kinases 1 and 2 by the pediatric preclinical testing program.

BACKGROUND: AZD1480 is an ATP competitive inhibitor of Janus kinases 1 and 2 (JAK1, 2) that has been shown to inhibit the growth of solid tumor models. This agent was selected for testing the putative role of JAK/STAT signaling in the standard PPTP solid tumor models. PROCEDURES: AZD1480 was tested against the PPTP in vitro cell line panel at concentrations from 1.0 nM to 10 µM and against the PPTP in vivo solid tumor xenograft panels at (60 mg/kg once daily (SID) × 5) for three consecutive weeks. Additional studies evaluated 5 to 20 mg/kg BID × 5 with SID dosing at 7-30 mg/kg at weekends for three consecutive weeks. RESULTS: In vitro the median relative IC50 (rIC50 ) for the PPTP cell lines was 1.5 µM, with a range from 0.3 µM to 5.9 µM. The two cell lines with rIC50 values of 0.3 µM both had ALK activating genomic alterations. AZD1480 demonstrated statistically significant differences (P < 0.05) in EFS distribution compared to control in 89% of the solid tumor xenografts. AZD1480 induced intermediate (EFS T/C > 2) or high-level growth inhibition in 15 of 30 (50%) solid tumor xenografts. Tumor regressions were observed in three of six Wilms tumor models at doses that induced inhibition of Stat3(Y705) phosphorylation. CONCLUSIONS: AZD1480 demonstrated significant tumor growth inhibition against most PPTP solid tumor xenografts, similar to that observed for antiangiogenic agents tested by the PPTP. Tumor regressing activity was noted for Wilms tumor xenografts.

Local complement activation and modulation in mucosal immunity.

The complement system is an evolutionarily conserved arm of innate immunity, which forms one of the first lines of host response to pathogens and assists in the clearance of debris. A deficiency in key activators/amplifiers of the cascade results in recurrent infection, whereas a deficiency in regulating the cascade predisposes to accelerated organ failure, as observed in colitis and transplant rejection. Given that there are over 60 proteins in this system, it has become an attractive target for immunotherapeutics, many of which are United States Food and Drug Administration-approved or in multiple phase 2/3 clinical trials. Moreover, there have been key advances in the last few years in the understanding of how the complement system operates locally in tissues, independent of its activities in circulation. In this review, we will put into perspective the abovementioned discoveries to optimally modulate the spatiotemporal nature of complement activation and regulation at mucosal surfaces.

P-glycoprotein (MDR1/ABCB1) and breast cancer resistance protein (BCRP/ABCG2) restrict brain accumulation of the JAK1/2 inhibitor, CYT387.

CYT387 is an orally bioavailable, small molecule inhibitor of Janus family of tyrosine kinases (JAK) 1 and 2. It is currently undergoing Phase I/II clinical trials for the treatment of myelofibrosis and myeloproliferative neoplasms. We aimed to establish whether the multidrug efflux transporters P-glycoprotein (P-gp; MDR1; ABCB1) and breast cancer resistance protein (BCRP;ABCG2) restrict oral availability and brain penetration of CYT387. In vitro, CYT387 was efficiently transported by both human MDR1 and BCRP, and very efficiently by mouse Bcrp1 and its transport could be inhibited by specific MDR1 inhibitor, zosuquidar and/or specific BCRP inhibitor, Ko143. CYT387 (10 mg/kg) was orally administered to wild-type (WT), Bcrp1(-/-), Mdr1a/1b(-/-) and Bcrp1;Mdr1a/1b(-/-) mice and plasma and brain concentrations were analyzed. Over 8h, systemic exposure of CYT387 was similar between all the strains, indicating that these transporters do not substantially limit oral availability of CYT387. Despite the similar systemic exposure, brain accumulation of CYT387 was increased 10.5- and 56-fold in the Bcrp1;Mdr1a/1b(-/-) mice compared to the WT strain at 2 and 8h after CYT387 administration, respectively. In single Bcrp1(-/-) mice, brain accumulation of CYT387 was more substantially increased than in Mdr1a/1b(-/-) mice, suggesting that CYT387 is a slightly better substrate of Bcrp1 than of Mdr1a at the blood-brain barrier. These results indicate a marked and additive role of Bcrp1 and Mdr1a/1b in restricting brain penetration of CYT387, potentially limiting efficacy of this compound against brain (micro) metastases positioned behind a functional blood-brain barrier.