Bcl-2 expression in rituximab refractory cutaneous B-cell lymphoma

Rituximab has been established as an effective and safe therapy for cutaneous B-cell lymphoma (CBCL). Different survival pathways, that is the Raf/MEK/Erk- or the p38MAPK cascade, have been suggested as downstream mediators of rituximab and may be involved in treatment failure. Biopsies from four patients, suffering from different subtypes of CBCL, which were obtained at various time points of relapse during or after therapy with 375 mg rituximab per m2 of body surface area, were analysed for the expression of CD20, CD3, Ki-67, Raf-kinase inhibitory protein (RKIP) and bcl-2 by immunohistochemistry. No CD20-loss variants, that is the suggested main tumour escape mechanism to rituximab therapy, were observed in any specimen of relapsing CBCL. Notably, the expression of proapoptotic RKIP remained increased in these tumour samples. This was concomitated by a constant to slightly reduced proliferation status as demonstrated by Ki-67 staining. However, relapsing CBCL exhibited a strong upregulation of the antiapoptotic molecule bcl-2 in comparison to pretherapeutic levels. The immunohistochemical analyses of this case series of rituximab refractory CBCL suggest that upregulation of bcl-2 may play a major role in therapy resistance

Notch-dependent repression of miR-155 in the bone marrow niche regulates hematopoiesis in an NF-κB-dependent manner

The microRNA miR-155 has been implicated in regulating inflammatory responses and tumorigenesis, but its precise role in linking inflammation and cancer has remained elusive. Here, we identify a connection between miR-155 and Notch signaling in this context. Loss of Notch signaling in the bone marrow (BM) niche alters hematopoietic homeostasis and leads to lethal myeloproliferative-like disease. Mechanistically, Notch signaling represses miR-155 expression by promoting binding of RBPJ to the miR-155 promoter. Loss of Notch/RBPJ signaling upregulates miR-155 in BM endothelial cells, leading to miR-155-mediated targeting of the nuclear factor κB (NF-κB) inhibitor κB-Ras1, NF-κB activation, and increased proinflammatory cytokine production. Deletion of miR-155 in the stroma of RBPJ(-/-) mice prevented the development of myeloproliferative-like disease and cytokine induction. Analysis of BM from patients carrying myeloproliferative neoplasia also revealed elevated expression of miR-155. Thus, the Notch/miR-155/κB-Ras1/NF-κB axis regulates the inflammatory state of the BM niche and affects the development of myeloproliferative disorders

The oral HDAC inhibitor pracinostat (SB939) is efficacious and synergistic with the JAK2 inhibitor pacritinib (SB1518) in preclinical models of AML

Acute myeloid leukemia (AML) is currently treated with aggressive chemotherapy that is not well tolerated in many elderly patients, hence the unmet medical need for effective therapies with less toxicity and better tolerability. Inhibitors of FMS-like tyrosine kinase 3 (FLT3), JAK2 and histone deacetylase inhibitors (HDACi) have been tested in clinical studies, but showed only moderate single-agent activity. High efficacy of the HDACi pracinostat treating AML and synergy with the JAK2/FLT3 inhibitor pacritinib is demonstrated. Both compounds inhibit JAK-signal transducer and activator of transcription (STAT) signaling in AML cells with JAK2V617F mutations, but also diminish FLT3 signaling, particularly in FLT3-ITD (internal tandem duplication) cell lines. In vitro, this combination led to decreased cell proliferation and increased apoptosis. The synergy translated in vivo in two different AML models, the SET-2 megakaryoblastic AML mouse model carrying a JAK2V617F mutation, and the MOLM-13 model of FLT3-ITD-driven AML. Pracinostat and pacritinib in combination showed synergy on tumor growth, reduction of metastases and synergistically decreased JAK2 or FLT signaling, depending on the cellular context. In addition, several plasma cytokines/growth factors/chemokines triggered by the tumor growth were normalized, providing a rationale for combination therapy with an HDACi and a JAK2/FLT3 inhibitor for the treatment of AML patients, particularly those with FLT3 or JAK2 mutations

Superior efficacy of co-targeting GFI1/KDM1A and BRD4 against AML and post-MPN secondary AML cells.

There is an unmet need to overcome nongenetic therapy-resistance to improve outcomes in AML, especially post-myeloproliferative neoplasm (MPN) secondary (s) AML. Studies presented describe effects of genetic knockout, degradation or small molecule targeted-inhibition of GFI1/LSD1 on active enhancers, altering gene-expressions and inducing differentiation and lethality in AML and (MPN) sAML cells. A protein domain-focused CRISPR screen in LSD1 (KDM1A) inhibitor (i) treated AML cells, identified BRD4, MOZ, HDAC3 and DOT1L among the codependencies. Our findings demonstrate that co-targeting LSD1 and one of these co-dependencies exerted synergistic in vitro lethality in AML and post-MPN sAML cells. Co-treatment with LSD1i and the JAKi ruxolitinib was also synergistically lethal against post-MPN sAML cells. LSD1i pre-treatment induced GFI1, PU.1 and CEBPα but depleted c-Myc, overcoming nongenetic resistance to ruxolitinib, or to BETi in post-MPN sAML cells. Co-treatment with LSD1i and BETi or ruxolitinib exerted superior in vivo efficacy against post-MPN sAML cells. These findings highlight LSD1i-based combinations that merit testing for clinical efficacy, especially to overcome nongenetic therapy-resistance in AML and post-MPN sAML

Hydrogen sulfide removal by Thiobacillus thioparus bacteria on seashell bed biofilters

The aim of this research is to achieve an efficient and cheap methods to remove H2S from the factories emissions. Four serial cylinders are designed, 40 cm in height and 15 cm in diameter each. They are filled with bivalve seashells with 63% porosity which contains Thiobacillus thioparus bacteria to the maximum height of 27.5 cm. By mixing phosphoric acid and sodium sulfide, H2S gas is released and its concentration is measured as mg m(-3) before injecting into the cylinders. A permanent measuring instrument is equipped to control the gas coming out of the cylinders. In order to prevent the outdoor environment from pollution, first the gas is sent through two activated carbon columns and then sent through a ferrous chloride scrubber. Finally it is burnt directly by flames. There were 550 sample readings in 15 weeks. The changes in the discharge of the air which carries the gas are considered between 1-12 L min(-1) and the concentration of the influent pollutant is considered between 1-140 mg m(-3). Also the humidity in the atmosphere is fixed between 77-93% and the optimum temperature required for growing of the microorganisms is retained between 20.5-30 degrees C. After feeding the system for three weeks the efficiency started to increase so that by the end of the final week of this research the efficiency reached to 90% with the discharge of 6 L min(-1) of the carrier gas. The results achieved from this research show that because of not using Filamentous bacteria, clogging did not occur in the biological system in biofilters. The amount of head loss in cylinder was only 2 mm water and during this research, head loss was the same due to unclogging of filter. On the other hand the traditional methods are expensive in terms of using chemicals, carbon recycling and using fuel and etc. Therefore researchers have started new studies in this field. The above mentioned method, according to high efficiency, inexpensiveness and easiness of control and maintenance is considered one of the best methods

Antigenic modulation limits the efficacy of anti-CD20 antibodies: implications for antibody selection

Rituximab, a monoclonal antibody which targets CD20 on B-cells, is now central to the treatment of a variety of malignant and autoimmune disorders. Despite this success a substantial proportion of B-cell lymphomas are unresponsive or develop resistance, hence more potent anti-CD20 mAb are continually being sought. Here we demonstrate that type II (tositumomab-like) anti-CD20 mAb are 5 times more potent than type I (rituximab-like) reagents in depleting human CD20 Tg B-cells, despite both operating exclusively via activatory FcR-expressing macrophages. Much of this disparity in performance is attributable to type I mAb-mediated internalization of CD20 by B-cells leading to reduced macrophage recruitment and the degradation of CD20:mAb complexes, shortening mAb half-life. Importantly, human B cells from healthy donors, and most cases of Chronic Lymphatic Leukemia (CLL) and Mantle Cell Lymphoma, showed rapid CD20 internalization which paralleled that seen in the Tg mouse B cells, while most Follicular Lymphoma (FL) and Diffuse Large B-Cell Lymphoma (DLBCL) cells were far more resistant to CD20 loss. We postulate that differences in CD20 modulation may play a central role in determining the relative efficacy of rituximab in treating these diseases and strengthen the case for focusing on type II anti-CD20 mAb in the clinic. <br/