[Clinical translation of genomic medicine]. / Stor potential när genomikdata kan implementeras i klinisk rutin.

Recent technical developments and early clinical examples support that precision medicine has potential to provide novel diagnostic and therapeutic solutions for patients with complex diseases, who are not responding to existing therapies. Those solutions will require integration of genomic data with routine clinical, imaging, sensor, biobank and registry data. Moreover, user-friendly tools for informed decision support for both patients and clinicians will be needed. While this will entail huge technical, ethical, societal and regulatory challenges, it may contribute to transforming and improving health care towards becoming predictive, preventive, personalised and participatory (4P-medicine).

Multiplexed single-cell mass cytometry reveals distinct inhibitory effects on intracellular phosphoproteins by midostaurin in combination with chemotherapy in AML cells.

BACKGROUND: Fms-related tyrosine kinase 3 (FLT3) receptor serves as a prognostic marker and therapeutic target in acute myeloid leukemia (AML). Approximately one-third of AML patients carry mutation in FLT3, associated with unfavourable prognosis and high relapse rate. The multitargeted kinase inhibitor midostaurin (PKC412) in combination with standard chemotherapy (daunorubicin and cytarabine) was recently shown to increase overall survival of AML patients. For that reason, PKC412 has been approved for treatment of AML patients with FLT3-mutation. PKC412 synergizes with standard chemotherapy, but the mechanism involved is not fully understood and the risk of relapse is still highly problematic. METHODS: By utilizing the unique nature of mass cytometry for single cell multiparameter analysis, we have explored the proteomic effect and intracellular signaling response in individual leukemic cells with internal tandem duplication of FLT3 (FLT3-ITD) after midostaurin treatment in combination with daunorubicin or cytarabine. RESULTS: We have identified a synergistic inhibition of intracellular signaling proteins after PKC412 treatment in combination with daunorubicin. In contrast, cytarabine antagonized phosphorylation inhibition of PKC412. Moreover, we found elevated levels of FLT3 surface expression after cytarabine treatment. Interestingly, the surface localization of FLT3 receptor increased in vivo on the blast cell population of two AML patients during day 3 of induction therapy (daunorubicin; once/day from day 1-3 and cytarabine; twice/day from day 1-7). We found FLT3 receptor expression to correlate with intracellular cytarabine (AraC) response. AML cell line cultured with AraC with or without PKC412 had an antagonizing phosphorylation inhibition of pAKT (p = 0.042 and 0.0261, respectively) and pERK1/2 (0.0134 and 0.0096, respectively) in FLT3high compared to FLT3low expressing cell populations. CONCLUSIONS: Our study provides insights into how conventional chemotherapy affects protein phosphorylation of vital signaling proteins in human leukemia cells. The results presented here support further investigation of novel strategies to treat FLT3-mutated AML patients with PKC412 in combination with chemotherapy agents and the potential development of novel treatment strategies.

How personalised medicine will transform healthcare by 2030: the ICPerMed vision.

This commentary presents the vision of the International Consortium for Personalised Medicine (ICPerMed) on how personalised medicine (PM) will lead to the next generation of healthcare by 2030. This vision focuses on five perspectives: individual and public engagement, involvement of health professionals, implementation within healthcare systems, health-related data, and the development of sustainable economic models that allow improved therapy, diagnostic and preventive approaches as new healthcare concepts for the benefit of the public. We further identify four pillars representing transversal issues that are crucial for the successful implementation of PM in all perspectives. The implementation of PM will result in more efficient and equitable healthcare, access to modern healthcare methods, and improved control by individuals of their own health data, as well as economic development in the health sector.

The Critical Role of Dysregulated RhoB Signaling Pathway in Radioresistance of Colorectal Cancer.

PURPOSE: To explore whether the Rho protein is involved in the radioresistance of colorectal cancer and investigate the underlying mechanisms. METHODS AND MATERIALS: Rho GTPase expression was measured after radiation treatment in colon cancer cells. RhoB knockout cell lines were established using the CRISPR/Cas9 system. In vitro assays and zebrafish embryos were used for analyzing radiosensitivity and invasive ability. Mass cytometry was used to detect RhoB downstream signaling factors. RhoB and Forkhead box M1 (FOXM1) expression were detected by immunohistochemistry in rectal cancer patients who participated in a radiation therapy trial. RESULTS: RhoB expression was related to radiation resistance. Complete depletion of the RhoB protein increased radiosensitivity and impaired radiation-enhanced metastatic potential in vitro and in zebrafish models. Probing signaling using mass cytometry-based single-cell analysis showed that the Akt phosphorylation level was inhibited by RhoB depletion after radiation. FOXM1 was downregulated in RhoB knockout cells, and the inhibition of FOXM1 led to lower survival rates and attenuated migration and invasion abilities of the cells after radiation. In the patients who underwent radiation therapy, RhoB overexpression was related to high FOXM1, late Tumor, Node, Metastasis stage, high distant recurrence, and poor survival independent of other clinical factors. CONCLUSIONS: RhoB plays a critical role in radioresistance of colorectal cancer through Akt and FOXM1 pathways.

Putative Role of Nuclear Factor-Kappa B But Not Hypoxia-Inducible Factor-1α in Hypoxia-Dependent Regulation of Oxidative Stress in Hematopoietic Stem and Progenitor Cells.

Aims: Adaptation to low oxygen of hematopoietic stem cells (HSCs) in the bone marrow has been demonstrated to depend on the activation of hypoxia-inducible factor (HIF)-1α as well as the limited production of reactive oxygen species (ROS). In this study, we aimed at determining whether HIF-1α is involved in protecting HSCs from ROS. Results: Oxidative stress was induced by DL-buthionine-(S,R)-sulfoximine (BSO)-treatment, which increases the mitochondrial ROS level. Hypoxia rescued Lineage-Sca-1+c-kit+ (LSK) cells from BSO-induced apoptosis, whereas cells succumbed to apoptosis in normoxia. Apoptosis in normoxia was inhibited with the antioxidant N-acetyl-L-cysteine or by overexpression of anti-apoptotic BCL-2. Moreover, stabilized expression of oxygen-insensitive HIFs could not protect LSK cells from oxidative stress-induced apoptosis at normoxia, neither could short hairpin RNA to Hif-1α inhibit the protective effects by hypoxia in LSK cells. Likewise, BSO treatment of LSK cells from Hif-1α knockout mice did not suppress the effects seen in hypoxia. Microarray analysis identified the nuclear factor-kappa B (NF-κB) pathway as a pathway induced by hypoxia. By using NF-κB lentiviral construct and DNA-binding assay, we found increased NF-κB activity in cells cultured in hypoxia compared with normoxia. Using an inhibitor against NF-κB activation, we could confirm the involvement of NF-κB signaling as BSO-mediated cell death was significantly increased in hypoxia after adding the inhibitor. Innovation: HIF-1α is not involved in protecting HSCs and progenitors to elevated levels of ROS on glutathione depletion during hypoxic conditions. Conclusion: The study proposes a putative role of NF-κB signaling as a hypoxia-induced regulator in early hematopoietic cells.

Switchable presentation of cytokines on electroactive polypyrrole surfaces for hematopoietic stem and progenitor cells.

Hematopoietic stem cells are used in transplantations for patients with hematologic malignancies. Scarce sources require efficient strategies of expansion, including polymeric biomaterials mimicking architectures of bone marrow tissue. Tissue microenvironment and mode of cytokine presentation strongly influence cell fate. Although several cytokines with different functions as soluble or membrane-bound mediators have already been identified, their precise roles have not yet been clarified. A need exists for in vitro systems that mimic the in vivo situation to enable such studies. One way is to establish surfaces mimicking physiological presentation using protein-immobilization onto polymer films. However these films merely provide a static presentation of the immobilized proteins. It would be advantageous to also dynamically change protein presentation and functionality to better reflect the in vivo conditions. The electroactive polymer polypyrrole shows excellent biocompatibility and electrochemically alters its surface properties, becoming an interesting choice for such setups. Here, we present an in vitro system for switchable presentation of membrane-bound cytokines. We use interleukin IL-3, known to affect hematopoiesis, and show that when immobilized on polypyrrole films, IL-3 is bioavailable for the bone marrow-derived FDC-P1 progenitor cell line. Moreover, IL-3 presentation can be successfully altered by changing the redox state of the film, in turn influencing FDC-P1 cell viability. This novel in vitro system provides a valuable tool for stimuli-responsive switchable protein presentation allowing the dissection of relevant mediators in stem and progenitor cell behavior.

The stem cell regulator PEDF is dispensable for maintenance and function of hematopoietic stem cells.

Pigment epithelium derived factor (PEDF), a ubiquitously expressed 50 kDa secreted glycoprotein, was recently discovered to regulate self-renewal of neural stem cells and have a supportive effect on human embryonic stem cell growth. Here, we analyzed expression of PEDF in the murine hematopoietic stem cell (HSC) compartments and found that PEDF is highly expressed in primary long-term HSCs. Therefore, we characterized the hematopoietic system in a knockout mouse model for PEDF and using this model we surprisingly found that PEDF is dispensable for HSC regulation. PEDF knockout mice exhibit normal hematopoiesis in steady state conditions and the absence of PEDF lead to normal regeneration capacity in a serial competitive transplantation setting. Additionally, PEDF-deficient cells exhibit unaltered lineage distribution upon serial transplantations. When human cord blood stem and progenitor cells were cultured in media supplemented with recombinant PEDF they did not show changes in growth potential. Taken together, we report that PEDF is not a critical regulatory factor for HSC function during regeneration in vivo or growth of human stem/progenitor cells in vitro.

Hypoxia Mediates Differential Response to Anti-EGFR Therapy in HNSCC Cells.

Despite advances in the head and neck squamous cell carcinoma (HNSCC) treatment modalities, drug resistance and cancer recurrence are often reported. Hypoxia signaling through hypoxia-inducible factor 1 (HIF-1) promotes angiogenesis and metastasis by inducing epithelial-mesenchymal-transition (EMT). The aim of this study was to evaluate the impact of hypoxia on response to therapy as well as EMT and expression of stem cell markers in HNSCC cells. Five HNSCC cell lines (UT-SCC-2, UT-SCC-14, LK0412, LK0827, and LK0923) were selected for this study. The treatment sensitivity for radiation, cisplatin, cetuximab, and dasatinib was assessed by crystal violet assay. Gene expression of EMT and cancer stem cell (CSC) markers as well as protein level of EGFR signaling molecules were analyzed by qPCR and western blotting, respectively. Unlike UT-SCC-14 and LK0827, the LK0412 cell line became significantly more sensitive to cetuximab in hypoxic conditions. This cetuximab sensitivity was efficiently reversed after suppression of HIF-1α with siRNA. Additionally, hypoxia-induced EMT and expression of stem cell markers in HNSCC cells was partially revoked by treatment with cetuximab or knockdown of HIF-1α. In summary, our study shows that hypoxia might have a positive influence on the anti-EGFR therapy effectiveness in HNSCC. However, due to heterogeneity of HNSCC lesions, targeting HIF-1α may not be sufficient to mediate such a response. Further studies identifying a trait of hypoxia-specific response to cetuximab in HNSCC are advisable.

Pyruvate dehydrogenase kinase 1 is essential for transplantable mouse bone marrow hematopoietic stem cell and progenitor function.

BACKGROUND: Accumulating evidence suggests that hypoxic areas in the bone marrow are crucial for maintenance of hematopoietic stem cells (HSCs) by supporting a quiescent state of cell cycle and regulating the transplantation capacity of long-term (LT)-HSCs. In addition, HSCs seem to express a metabolic profile of energy production away from mitochondrial oxidative phosphorylation in favor of glycolysis. At oxygen deprivation, hypoxia inducible factor 1α (HIF-1α) is known to induce glycolytic enzymes as well as suppressing mitochondrial energy production by inducing pyruvate dehydrogenase kinase 1 (Pdk1) in most cell types. It has not been established whether PDK1 is essential for HSC function and mediates hypoxia-adapting functions in HSCs. While the Pdk gene family contains four members (Pdk1-4), it was recently shown that Pdk2 and Pdk4 have an important role in regulating LT-HSCs. PRINCIPLE FINDINGS: Here we demonstrate that PDK1 activity is crucial for transplantable HSC function. Whereas Pdkl, Pdk2, and Pdk3 transcripts were expressed at higher levels in different subtypes of HSCs compared to differentiated cells, we could not detect any major differences in expression between LT-HSCs and more short-term HSCs and multipotent progenitors. When studying HIF-1α-mediated regulation of Pdk activity in vitro, Pdk1 was the most robust target regulated by hypoxia, whereas Pdk2, Pdk3, and Pdk4 were not affected. Contrary, genetic ablation in a cre-inducible Hif-1α knockout mouse did not support a link between HIF-1α and Pdk1. Silencing of Pdk1 by shRNA lentiviral gene transfer partially impaired progenitor colony formation in vitro and had a strong negative effect on both long-term and short-term engraftment in mice. CONCLUSIONS: Our study demonstrates that PDK1 has broad effects in hematopoiesis and is a critical factor for engraftment of both HSCs and multipotent progenitors upon transplantation to recipient mice. While Pdk1 was a robust hypoxia-inducible gene mediated by HIF-1α in vitro, we could not find evidence of any in vivo links between Pdk1 and HIF-1α.

Coexpression of hyperactivated AKT1 with additional genes activated in leukemia drives hematopoietic progenitor cells to cell cycle block and apoptosis.

The phosphatidylinositol 3-kinase/AKT pathway is an integral component of signaling involved in the development of many cancers, including myeloid leukemias such as chronic myeloid leukemia and acute myeloid leukemia (AML). Increased AKT1 activity is frequently seen in AML patients, providing leukemic cells with growth and survival promoting signals. An important aspect of AKT1 function is its involvement in cellular metabolism and energy production. Under some circumstances, strong activation of AKT1 increases oxidative stress, which can cause apoptosis when cells progressively build up excess free radicals. This has been described in hematopoietic cells overexpressing activated AKT1; however, whether this is true in cells coexpressing other genetic events involved in leukemia is not known. This prompted us to investigate the effect of constitutively active AKT1 (myristoylated AKT1) in hematopoietic progenitor cells expressing constitutively active signal transducer and activator of transcription 5, Fms-related tyrosine kinase 3-internal tandem duplication, or antiapoptotic B-cell lymphoma 2. Surprisingly, myristoylated AKT1 was incompatible with proliferation driven by both signal transducer and activator of transcription 5 and Fms-related tyrosine kinase 3-internal tandem duplication, which triggered cell cycle block and apoptosis. Moreover, transplantable cells of B-cell lymphoma 2-transgenic mice were impaired in their engraftment ability to recipient mice when expressing hyperactivated AKT1. This was linked to AKT1-mediated proapoptotic functions and not to impairment in homing to the bone marrow. Although cells expressing hyperactivated AKT1 displayed higher levels of reactive oxygen species both in vitro and in vivo, the addition of the antioxidant N-acetyl-L-cysteine significantly reduced apoptosis. Taken together, the results indicate that constitutive AKT1 activity is incompatible with growth- and survival-promoting ability of other activated genes in AML.

Interleukin-1ß induced activation of the hypothalamus-pituitary-adrenal axis is dependent on interleukin-1 receptors on non-hematopoietic cells.

The proinflammatory cytokine interleukin-1ß (IL-1ß) plays a major role in the signal transduction of immune stimuli from the periphery to the central nervous system, and has been shown to be an important mediator of the immune-induced stress hormone release. The signaling pathway by which IL-1ß exerts this function involves the blood-brain-barrier and induced central prostaglandin synthesis, but the identity of the blood-brain-barrier cells responsible for this signal transduction has been unclear, with both endothelial cells and perivascular macrophages suggested as critical components. Here, using an irradiation and transplantation strategy, we generated mice expressing IL-1 type 1 receptors (IL-1R1) either in hematopoietic or non-hematopoietic cells and subjected these mice to peripheral immune challenge with IL-1ß. Following both intraperitoneal and intravenous administration of IL-1ß, mice lacking IL-1R1 in hematopoietic cells showed induced expression of the activity marker c-Fos in the paraventricular hypothalamic nucleus, and increased plasma levels of ACTH and corticosterone. In contrast, these responses were not observed in mice with IL-1R1 expression only in hematopoietic cells. Immunoreactivity for IL-1R1 was detected in brain vascular cells that displayed induced expression of the prostaglandin synthesizing enzyme cyclooxygenase-2 and that were immunoreactive for the endothelial cell marker CD31, but was not seen in cells positive for the brain macrophage marker CD206. These results imply that activation of the HPA-axis by IL-1ß is dependent on IL-1R1s on non-hematopoietic cells, such as brain endothelial cells, and that IL-1R1 on perivascular macrophages are not involved.

miR-20b regulates expression of proteinase-activated receptor-1 (PAR-1) thrombin receptor in melanoma cells.

The proteinase-activated receptor 1 (PAR-1) plays a central role in melanoma progression and its expression level is believed to correlate with the degree of cancer invasiveness. Here, we show that PAR-1 is post-transcriptionally regulated by miR-20b microRNA in human melanoma cells. PAR-1 was found to be expressed in metastatic melanoma cells but was barely detectable in primary melanoma. By transducing primary melanoma cells with a lentivirus containing a 3'-UTR construct of PAR-1 mRNA, we could show that endogenous melanoma microRNAs interacted with PAR-1 3'-UTR and silenced a fused luciferase reporter. Transfection of an inhibitor against miR-20b into primary melanoma cells reversed this process. Finally, transfection of miR-20b mimic into metastatic melanoma cells caused downregulation of the luciferase reporter. We conclude that miR-20b regulates expression of melanoma PAR-1 receptor, which may explain the differential expression of PAR-1 observed in human melanoma.

Single-nucleotide polymorphisms of ABCG2 increase the efficacy of tyrosine kinase inhibitors in the K562 chronic myeloid leukemia cell line.

OBJECTIVE: The tyrosine kinase inhibitors (TKIs) used in the treatment of chronic myeloid leukemia are substrates for the efflux transport protein ATP-binding cassette subfamily G member 2 (ABCG2). Variations in ABCG2 activity might influence pharmacokinetics and therapeutic outcome of TKIs. The role of ABCG2 single-nucleotide polymorphisms (SNPs) in TKI treatment is not clear and functional in-vitro studies are lacking. The aim of this study was to investigate the consequences of ABCG2 SNPs for transport and efficacy of TKIs [imatinib, N-desmethyl imatinib (CGP74588), dasatinib, nilotinib, and bosutinib]. MATERIALS AND METHODS: ABCG2 SNPs 34G>A, 421C>A, 623T>C, 886G>C, 1574T>G, and 1582G>A were constructed from ABCG2 wild-type cDNA and transduced to K562 cells by retroviral gene transfer. Variant ABCG2 expression in cell membranes was evaluated and the effects of ABCG2 SNPs on transport and efficacy of TKIs were measured as the ability of ABCG2 variants to protect against TKI cytotoxicity. RESULTS: Wild-type ABCG2 had a protective effect against the cytotoxicity of all investigated compounds except bosutinib. It was found that ABCG2 expression provided better protection against CGP74588 than its parent compound, imatinib. ABCG2 421C>A, 623T>C, 886G>C, and 1574T>G reduced cell membrane expression of ABCG2 and the protective effect of ABCG2 against imatinib, CGP74588, dasatinib, and nilotinib cytotoxicity. CONCLUSION: These findings show that the ABCG2 SNPs 421C>A, 623T>C, 886G>C, and 1574T>G increase the efficacy of investigated TKIs, indicating a reduced transport function that might influence TKI pharmacokinetics in vivo. Furthermore, the active imatinib metabolite CGP74588 is influenced by ABCG2 expression to a greater extent than the parent compound.

ABCB1 haplotypes do not influence transport or efficacy of tyrosine kinase inhibitors in vitro.

Single-nucleotide polymorphisms (SNPs) in the gene coding for the efflux-transport protein ABCB1 (P-glycoprotein) are commonly inherited as haplotypes. ABCB1 SNPs and haplotypes have been suggested to influence the pharmacokinetics and therapeutic outcome of the tyrosine kinase inhibitor (TKI) imatinib, used for treatment of chronic myeloid leukemia (CML). However, no consensus has yet been reached with respect to the significance of variant ABCB1 in CML treatment. Functional studies of variant ABCB1 transport of imatinib as well as other TKIs might aid the interpretation of results from in vivo association studies, but are currently lacking. The aim of this study was to investigate the consequences of ABCB1 variant haplotypes for transport and efficacy of TKIs (imatinib, its major metabolite N-desmethyl imatinib [CGP74588], dasatinib, nilotinib, and bosutinib) in CML cells. Variant haplotypes - including the 61A>G, 1199G>A, 1236C>T, 1795G>A, 2677G>T/A, and 3435T>C SNPs - were constructed in ABCB1 complementary DNA and transduced to K562 cells using retroviral gene transfer. The ability of variant cells to express ABCB1 protein and protect against TKI cytotoxicity was investigated. It was found that dasatinib and the imatinib metabolite CGP74588 are effectively transported by ABCB1, while imatinib, nilotinib, and bosutinib are comparatively weaker ABCB1 substrates. None of the investigated haplotypes altered the protective effect of ABCB1 expression against TKI cytotoxicity. These findings imply that the ABCB1 haplotypes investigated here are not likely to influence TKI pharmacokinetics or therapeutic efficacy in vivo.

Interleukin-6 primarily produced by non-hematopoietic cells mediates the lipopolysaccharide-induced febrile response.

Interleukin-6 (IL-6) is critical for the lipopolysaccharide (LPS)-induced febrile response. However, the exact source(s) of IL-6 involved in regulating the LPS-elicited fever is still to be identified. One known source of IL-6 is hematopoietic cells, such as monocytes. To clarify the contribution of hematopoietically derived IL-6 to fever, we created chimeric mice expressing IL-6 selectively either in cells of hematopoietic or, conversely, in cells of non-hematopoietic origin. This was performed by extinguishing hematopoietic cells in wild-type (WT) or IL-6 knockout (IL-6 KO) mice by whole-body irradiation and transplanting them with new stem cells. Mice on a WT background but lacking IL-6 in hematopoietic cells displayed normal fever to LPS and were found to have similar levels of IL-6 protein in the cerebrospinal fluid (CSF) and in plasma and of IL-6 mRNA in the brain as WT mice. In contrast, mice on an IL-6 KO background, but with intact IL-6 production in cells of hematopoietic origin, only showed a minor elevation of the body temperature after peripheral LPS injection. While they displayed significantly elevated levels of IL-6 both in plasma and CSF compared with control mice, the increase was modest compared with that seen in LPS injected mice on a WT background, the latter being approximately 20 times larger in magnitude. These results suggest that IL-6 of non-hematopoietic origin is the main source of IL-6 in LPS-induced fever, and that IL-6 produced by hematopoietic cells only plays a minor role.

Lipopolysaccharide-induced fever depends on prostaglandin E2 production specifically in brain endothelial cells.

Immune-induced prostaglandin E2 (PGE2) synthesis is critical for fever and other centrally elicited disease symptoms. The production of PGE2 depends on cyclooxygenase-2 and microsomal prostaglandin E synthase-1 (mPGES-1), but the identity of the cells involved has been a matter of controversy. We generated mice expressing mPGES-1 either in cells of hematopoietic or nonhematopoietic origin. Mice lacking mPGES-1 in hematopoietic cells displayed an intact febrile response to lipopolysaccharide, associated with elevated levels of PGE2 in the cerebrospinal fluid. In contrast, mice that expressed mPGES-1 only in hematopoietic cells, although displaying elevated PGE2 levels in plasma but not in the cerebrospinal fluid, showed no febrile response to lipopolysaccharide, thus pointing to the critical role of brain-derived PGE2 for fever. Immunohistochemical stainings showed that induced cyclooxygenase-2 expression in the brain exclusively occurred in endothelial cells, and quantitative PCR analysis on brain cells isolated by flow cytometry demonstrated that mPGES-1 is induced in endothelial cells and not in vascular wall macrophages. Similar analysis on liver cells showed induced expression in macrophages and not in endothelial cells, pointing at the distinct role for brain endothelial cells in PGE2 synthesis. These results identify the brain endothelial cells as the PGE2-producing cells critical for immune-induced fever.

The Q705K polymorphism in NLRP3 is a gain-of-function alteration leading to excessive interleukin-1ß and IL-18 production.

BACKGROUND: The Q705K polymorphism in NLRP3 has been implicated in several chronic inflammatory diseases. In this study we determine the functional role of this commonly occurring polymorphism using an in-vitro system. PRINCIPAL FINDINGS: NLRP3-WT and NLRP3-Q705K were retrovirally transduced into the human monocytic cell line THP-1, followed by the assessment of IL-1ß and IL-18 levels in the cell culture supernatant. THP-1 cells expressing the above NLRP3 variants were sorted based upon Green Fluorescent Protein (GFP) expression. Cytokine response to alum (one of the most widely used adjuvants in vaccines) in the cells stably expressing NLRP3-WT and NLRP3-Q705K were determined. IL-1ß and IL-18 levels were found to be elevated in THP-1 cells transduced with NLRP3-Q705K compared to the NLRP3-WT. Upon exposure to alum, THP-1 cells stably expressing NLRP3-Q705K displayed an increased release of IL-1ß, IL-18 and TNF-α, in a caspase-1 and IL-1 receptor-dependent manner. CONCLUSIONS: Collectively, these findings show that the Q705K polymorphism in NLRP3 is a gain-of-function alteration leading to an overactive NLRP3 inflammasome. The option of IL-1ß blockade may be considered in patients with chronic inflammatory disorders that are unresponsive to conventional treatments.

Irreversible pan-ERBB inhibitor canertinib elicits anti-leukaemic effects and induces the regression of FLT3-ITD transformed cells in mice.

Recent findings have indicated that tyrosine kinase inhibitors (TKIs) targeting the ERBB receptor family display anti-leukaemic effects, despite the lack of receptor expression on human leukaemic cells. The occurrence of activating mutations in the gene encoding FMS-like tyrosine kinase 3 (FLT3) in patients with acute myeloid leukaemia (AML) has rendered inhibition of this receptor a promising therapeutic target. Due to possibility of cross-reactivity, we investigated the effect of the irreversible pan-ERBB inhibitor canertinib (CI-1033) on leukaemic cells expressing FLT3. The drug had anti-proliferative and apoptotic effects on primary AML cells and human leukaemic cell lines expressing mutated FLT3. In several AML patient samples, a blast cell population expressing FLT3-internal tandem duplication (ITD) was eradicated by canertinib. Canertinib inhibited receptor autophosphorylation and kinase activity of both mutated and FLT3 ligand stimulated wildtype FLT3, leading to inhibition of the PI3-kinase and MAP kinase pathways. Apoptotic induction was dependent on pro-apoptotic BH3-only protein BCL2L11/BIM because siRNA silencing attenuated apoptosis. Moreover, the drug induced regression of cells expressing FLT3-ITD in a murine in vivo-transplantation model at previously described tolerated doses. These results indicate that canertinib, as an irreversible TKI, could constitute a novel treatment regimen in patients with mutated or overexpressed FLT3.

IL-7 mediates Ebf-1-dependent lineage restriction in early lymphoid progenitors.

Deficiencies in the IL-7 signaling pathway result in severe disruptions of lymphoid development in adult mice. To understand more about how IL-7 deficiency impacts early lymphoid development, we have investigated lineage restriction events within the common lymphoid progenitor (CLP) compartment in IL-7 knockout mice. This revealed that although IL-7 deficiency had a minor impact on the development of LY6D(-) multipotent CLPs, the formation of the lineage restricted LY6D(+) CLP population was dramatically reduced. This was reflected in a low-level transcription of B-lineage genes as well as in a loss of functional B-cell commitment. The few Ly6D(+) CLPs developed in the absence of IL-7 displayed increased lineage plasticity and low expression of Ebf-1. Absence of Ebf-1 could be linked to increased plasticity because even though Ly6D(+) cells develop in Ebf-1-deficient mice, these cells retain both natural killer and dendritic cell potential. This reveals that IL-7 is essential for normal development of Ly6D(+) CLPs and that Ebf-1 is crucial for lineage restriction in early lymphoid progenitors.