Acentrosomal spindle organization renders cancer cells dependent on the kinesin HSET.

Centrosomes represent the major microtubule organizing centers (MTOCs) of animal somatic cells and orchestrate bipolar spindle assembly during mitotic cell division. In meiotic cells, the kinesin HSET compensates for the lack of centrosomes by focusing acentrosomal MTOCs into two spindle poles. By clustering multiple centrosomes into two spindle poles, HSET also mediates bipolar mitosis in cancer cells with supernumerary centrosomes. However, although dispensable in non-transformed human cells, the role of HSET in cancer cells with two centrosomes has remained elusive. In this study, we demonstrate that HSET is required for proper spindle assembly, stable pole-focusing and survival of cancer cells irrespective of normal or supernumerary centrosome number. Strikingly, we detected pronounced acentrosomal MTOC structures in untreated mitotic cancer cells. While in most cancer cells these acentrosomal MTOCs were rapidly incorporated into the assembling bipolar spindle, some cells eventually established bipolar spindles with acentrosomal poles and free centrosomes. These observations demonstrate that acentrosomal MTOCs were functional and that both centrosomal and acentrosomal mechanisms were required for bipolar spindle organization. Our study shows that HSET is critical for clustering acentrosomal and centrosomal MTOCs during spindle formation in human cancer cells with two bona fide centrosomes. Furthermore, we show that in checkpoint-defective cancer cells, acentrosomal spindle formation and HSET-dependence are partially mediated by a constitutive activation of the DNA damage response. In summary, we propose that acentrosomal spindle assembly mechanisms are hyperactive in cancer cells and promote HSET, a key driver of acentrosomal spindle organization, as an attractive target for cancer therapy.

Th17 cells, not IL-17+ γδ T cells, drive arthritic bone destruction in mice and humans.

The mechanism whereby IL-17 drives rheumatoid arthritis remains incompletely understood. We demonstrate that anti-IL-17 therapy in collagen-induced arthritis ameliorates bone damage by reducing the number of osteoclasts in joints. We found equal numbers of CD4(+) Th17 and IL-17 producing γδ T cells in the joints of arthritic mice, and in vitro, both populations similarly induced osteoclastogenesis. However, individual depletion and adoptive transfer studies revealed that in vivo, Th17 cells dominated with regard to bone destruction. Unlike γδ T cells, Th17 cells were found in apposition to tartrate-resistant acid phosphatase positive osteoclasts in subchondral areas of inflamed joints, a pattern reproduced in patient biopsies. This localization was caused by Ag-specific retention, because OVA-primed Th17 cells showed a γδ T cell-like diffuse distribution. Because IL-23, as produced by osteoclasts, enhanced T cell-mediated osteoclastogenesis, we propose that Ag-specific juxtaposition is key to foster the molecular cross talk of Th17 cells and osteoclasts, thus driving arthritic bone destruction.

Angiogenesis is present in experimental autoimmune encephalomyelitis and pro-angiogenic factors are increased in multiple sclerosis lesions.

BACKGROUND: Angiogenesis is a common finding in chronic inflammatory diseases; however, its role in multiple sclerosis (MS) is unclear. Central nervous system lesions from both MS and experimental autoimmune encephalomyelitis (EAE), the animal model of MS, contain T cells, macrophages and activated glia, which can produce pro-angiogenic factors. Previous EAE studies have demonstrated an increase in blood vessels, but differences between the different phases of disease have not been reported. Therefore we examined angiogenic promoting factors in MS and EAE lesions to determine if there were changes in blood vessel density at different stages of EAE. METHODS: In this series of experiments we used a combination of vascular casting, VEGF ELISA and immunohistochemistry to examine angiogenesis in experimental autoimmune encephalomyelitis (EAE). Using immunohistochemistry we also examined chronic active MS lesions for angiogenic factors. RESULTS: Vascular casting and histological examination of the spinal cord and brain of rats with EAE demonstrated that the density of patent blood vessels increased in the lumbar spinal cord during the relapse phase of the disease (p < 0.05). We found an increased expression of VEGF by inflammatory cells and a decrease in the recently described angiogenesis inhibitor meteorin. Examination of chronic active human MS tissues demonstrated glial expression of VEGF and glial and blood vessel expression of the pro-angiogenic receptor VEGFR2. There was a decreased expression of VEGFR1 in the lesions compared to normal white matter. CONCLUSIONS: These findings reveal that angiogenesis is intimately involved in the progression of EAE and may have a role in MS.

Costs of dose escalation among ulcerative colitis patients treated with adalimumab in Germany.

AIMS: We determined adalimumab utilisation and associated drug costs in patients with ulcerative colitis (UC), focusing on patients requiring dose escalation. METHODS: The retrospective cohort study analysed the de-identified prescription data of the Arvato Health Analytics (Munich, Germany) database (2010-2015) in adult UC patients undergoing adalimumab therapy. RESULTS: A total of 154 patients were newly treated with adalimumab (average 39.6 years, 53% females), with a mean dose of 2.93 mg/day. Within 12 months, 69 patients (45%) received a dose increase of > 50% (doubled dose in 48 patients; 32%), with the escalation reported at 169.3 ± 99.3 days. A subsequent dose de-escalation to the standard dose occurred in 50 (32%) of patients that initially had a dose increase of > 50% (after 94.7 ± 49.6 days). Direct drug costs were 28,846 € in the overall study population, 24,934 € in patients on standard dose, 36,094 € in patients with dose increase, and 32,742 € in patients with increase and subsequent decrease. CONCLUSION: Dose escalation occurred frequently, and in one third of patients the dose was at least doubled. Dose escalations were associated with substantial increases in direct drug costs. Dose escalation of adalimumab can severely affect both the health care system and the drug budget of the physician. It needs to be considered that other biologic medications may constitute a more cost-effective alternative.

Treatment patterns, health care resource use and outcomes in metastatic triple-negative breast cancer in Germany: retrospective chart review study (OBTAIN).

Background: There is limited data on the real-life situation and outcomes of patients with metastatic triple-negative breast cancer (mTNBC) in Germany. The aim of this chart review was to describe the current treatment patterns, resource use and outcomes in this patient group. Methods: Retrospective data collection in 30 gyneco-oncological sites (hospitals and office-based) across Germany between January and April 2017. Index date was defined as initiation of treatment with gemcitabine, vinorelbin, capecitabine or eribulin therapy following discontinuation of taxane and/or anthracycline therapy. Results: In the 91 evaluable patients, median time between primary diagnosis and index date was 20.9 months (range 0-187 months). Ten percent of patients had no distant metastases, while 57% had newly diagnosed metastases. Cancer stage at index date was mostly IV (82 patients). A number of 135 different regimens (monotherapy or combination therapy) were used. For first-line chemo treatment, 29 patients received monotherapy and 54 patients combination therapy. Bevacizumab and paclitaxel were also the most frequently used single substances among all therapy lines together and for first-line therapy. While taxanes were at least occasionally administered for second-line therapy, no patient received taxanes for third-line therapy. Chemotherapy modifications in terms of dose reduction or treatment interruption were rare. However, the therapy was terminated in more than two thirds of all cases. Fifty-nine patients were hospitalized at least once. For first-, second- and third-line therapy, median overall survival was 19.1/10.8/14.6 months, and median progression-free survival was 7.7/2.5/5.6 months. Conclusion: In clinical routine, a wide variety of treatment approaches is applied, while outcomes in terms of survival are poor. New treatment options are needed for this challenging tumor type.

Methyldopa blocks MHC class II binding to disease-specific antigens in autoimmune diabetes.

Major histocompatibility (MHC) class II molecules are strongly associated with many autoimmune disorders. In type 1 diabetes (T1D), the DQ8 molecule is common, confers significant disease risk, and is involved in disease pathogenesis. We hypothesized that blocking DQ8 antigen presentation would provide therapeutic benefit by preventing recognition of self-peptides by pathogenic T cells. We used the crystal structure of DQ8 to select drug-like small molecules predicted to bind structural pockets in the MHC antigen-binding cleft. A limited number of the predicted compounds inhibited DQ8 antigen presentation in vitro, with 1 compound preventing insulin autoantibody production and delaying diabetes onset in an animal model of spontaneous autoimmune diabetes. An existing drug with a similar structure, methyldopa, specifically blocked DQ8 in patients with recent-onset T1D and reduced inflammatory T cell responses to insulin, highlighting the relevance of blocking disease-specific MHC class II antigen presentation to treat autoimmunity.

IL-17 producing T cells in mouse models of multiple sclerosis and rheumatoid arthritis.

Multiple Sclerosis (MS) and Rheumatoid Arthritis (RA) are amongst the most common autoimmune diseases in the northern hemisphere. There is mounting evidence that in both afflictions, not only environmental and genetic factors influence disease, but cellular components such as autoreactive T cells also contribute to pathology. Animal models are key in the study and subsequent therapeutic development for human autoimmune diseases. As patient material is often difficult to obtain and in some cases--as in MS, where the central nervous system (CNS) is concerned--even not accessible, animal models provide a multifaceted tool to explore disease-underlying mechanisms. The pro-inflammatory T cell cytokine IL-17 has recently moved to center stage due to its crucial role in autoimmune diseases including MS and RA. A plethora of studies in animal models has sustained the relevance of this cytokine pathway for the development of autoimmunity and shed light on its cellular sources and patho-mechanisms. This review addresses the role of IL-17 producing T lymphocytes, in particular CD4(+) and γδ T cells, in three commonly used mouse models for MS and RA, namely experimental autoimmune encephalomyelitis (EAE), collagen-induced arthritis (CIA), and antigen-induced arthritis (AIA). Comparing and combining knowledge gained from different animal models will broaden our understanding of the IL-17 biology and facilitate the translation to the human diseases.

The critical role of kinase activity of interleukin-1 receptor-associated kinase 4 in animal models of joint inflammation.

OBJECTIVE: We have previously reported that the kinase activity of interleukin-1 receptor-associated kinase 4 (IRAK-4) is important for Toll-like receptor and interleukin-1 receptor signaling in vitro. Using mice devoid of IRAK-4 kinase activity (IRAK-4 KD mice), we undertook this study to determine the importance of IRAK-4 kinase function in complex disease models of joint inflammation. METHODS: IRAK-4 KD mice were subjected to serum transfer-induced (K/BxN) arthritis, and migration of transferred spleen lymphocytes into joints and cartilage and bone degradation were assessed. T cell response in vivo was tested in antigen-induced arthritis (AIA) by measuring the T cell-dependent antigen-specific IgG production and frequency of antigen-specific T cells in the spleen and lymph nodes. T cell allogeneic response was tested in vitro by mixed lymphocyte reaction (MLR). RESULTS: Lipopolysaccharide-induced local neutrophil influx into subcutaneous air pouches was impaired in IRAK-4 KD mice. These mice were also protected from inflammation in the K/BxN and AIA models, as shown by reduced swelling of joints. Histologic analysis of joints of K/BxN serum-injected mice revealed that bone erosion, osteoclast formation, and cartilage matrix proteoglycan loss were reduced in IRAK-4 KD mice. Assessment of T cell response by MLR, by frequency of antigen-specific clones, and by production of antigen-specific IgG did not reveal substantial differences between IRAK-4 KD and wild-type mice. CONCLUSION: These results demonstrate that IRAK-4 is a key component for the development of proarthritis inflammation, but that it is not crucial for T cell activation. Therefore, the kinase function of IRAK-4 appears to be an attractive therapeutic target in chronic inflammation.

Spontaneous relapsing-remitting EAE in the SJL/J mouse: MOG-reactive transgenic T cells recruit endogenous MOG-specific B cells.

We describe new T cell receptor (TCR) transgenic mice (relapsing-remitting [RR] mice) carrying a TCR specific for myelin oligodendrocyte glycoprotein (MOG) peptide 92-106 in the context of I-A(s). Backcrossed to the SJL/J background, most RR mice spontaneously develop RR experimental autoimmune encephalomyelitis (EAE) with episodes often altering between different central nervous system tissues like the cerebellum, optic nerve, and spinal cord. Development of spontaneous EAE depends on the presence of an intact B cell compartment and on the expression of MOG autoantigen. There is no spontaneous EAE development in B cell-depleted mice or in transgenic mice lacking MOG. Transgenic T cells seem to expand MOG autoreactive B cells from the endogenous repertoire. The expanded autoreactive B cells produce autoantibodies binding to a conformational epitope on the native MOG protein while ignoring the T cell target peptide. The secreted autoantibodies are pathogenic, enhancing demyelinating EAE episodes. RR mice constitute the first spontaneous animal model for the most common form of multiple sclerosis (MS), RR MS.