Anti-CD20 antibody rituximab is now essential for the treatment of CD20-positive B-cell lymphomas. Decreased expression of CD20 is one of the major mechanisms underlying both innate and acquired ...resistance to rituximab. In this study, we show that histone deacetylase (HDAC) inhibitors augment the cytotoxic activity of rituximab by enhancing the surface expression of CD20 antigen on lymphoma cells. HDAC inhibitors, valproic acid (VPA) and romidepsin, increased CD20 expression at protein and mRNA levels in B-cell lymphoma cell lines with relatively low CD20 expression levels. The VPA-mediated increase in CD20 expression occurred at 1 m, which is clinically achievable and safe, but insufficient for inducing cell death. Chromatin immunoprecipitation assays revealed that HDAC inhibitors transactivated the CD20 gene through promoter hyperacetylation and Sp1 recruitment. HDAC inhibitors potentiated the activity of rituximab in complement-dependent cytotoxic assays. In mouse lymphoma models, HDAC inhibitors enhanced CD20 expression along with histone hyperacetylation in transplanted cells, and acted synergistically with rituximab to retard their growth. The combination with HDAC inhibitors may serve as an effective strategy to overcome rituximab resistance in B-cell lymphomas.
Hemorrhagic shock and encephalopathy syndrome (HSES) is the most severe form of acute encephalopathy that progresses rapidly, often resulting in death or severe neurological sequelae. We report the ...case of a 4-year-old girl with HSES with shock and impaired consciousness.
Blood test results showed hypercytokinemia, and the 4-year-old patient was immediately admitted to the intensive care unit. Within 4 h of symptom onset, she received mild brain hypothermia therapy with a target body temperature of 35°C. Methylprednisolone pulse, high dose immunoglobulin, and large doses of circulatory drugs were administered.
After 72 h of brain hypothermia therapy, targeted temperature management with a target body temperature between 36°C and 37°C was continued for 96 h. The patient was diagnosed with HSES based on acute encephalopathy with shock, hypercytokinemia, low platelet count, coagulation disorder, renal damage, and intestinal bleeding. Magnetic resonance imaging results revealed no signs of any specific acute encephalopathy. She was discharged without neurological sequelae 28 days after symptom onset.
Mild brain hypothermia therapy initiated in the early stages followed by targeted temperature management may be an effective way to improve neurological outcomes in children suffering from HSES.
Tumor suppressor protein p19(ARF) (Arf; p14(ARF) in humans) functions in both p53-dependent and -independent modes to counteract hyper-proliferative signals caused by proto-oncogene activation, but ...its p53-independent activities remain poorly understood. Using the tandem affinity purification-tag technique, we purified Arf-containing protein complexes and identified p68 DEAD-box protein (DDX5) as a novel interacting protein of Arf. In this study, we found that DDX5 interacts with c-Myc, and harbors essential roles for c-Myc-mediated transcription and its transforming activity. Furthermore, when c-Myc was forcibly expressed, the expression level of DDX5 protein was drastically increased through the acceleration of protein synthesis of DDX5, suggesting the presence of an oncogenic positive feedback loop including c-Myc and DDX5. Strikingly, Arf blocked the physical interaction between DDX5 and c-Myc, and drove away DDX5 from the promoter of c-Myc target genes. These observations most likely indicate the mechanism by which Arf causes p53-independent tumor-suppressive activity.
Notch receptor has an important role in both development and cancer. We previously reported that inhibition of the Notch3 by γ-secretase inhibitor (GSI) induces apoptosis and suppresses tumour ...proliferation in non-small-cell lung cancer. Although radiation is reported to induce Notch activation, little is known about the relationship between radiation and Notch pathway.
We examined the effect of combining GSI and radiation at different dosing in three Notch expressing lung cancer cell lines. The cytotoxic effect of GSI and radiation was evaluated using MTT assay and clonogenic assay in vitro and xenograft models. Expressions of Notch pathway, mitogen-activated protein kinase (MAPK) pathway and Bcl-2 family proteins were investigated using western blot analysis.
We discovered that the antitumour effect of combining GSI and radiation was dependent on treatment schedule. γ-Secretase inhibitor administration after radiation had the greatest growth inhibition of lung cancer in vitro and in vivo. We showed that the combination induced apoptosis of lung cancer cell lines through the regulation of MAPK and Bcl-2 family proteins. Furthermore, activation of Notch after radiation was ameliorated by GSI administration, suggesting that treatment with GSI prevents Notch-induced radiation resistance.
Notch has an important role in lung cancer. Treatment with GSI after radiation can significantly enhance radiation-mediated tumour cytotoxicity.
The Notch signaling pathway has been recognized as a key factor for the pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL), because of the high incidence of activating mutations of Notch1. ...Notch inhibition could serve as a new treatment strategy for T-ALL; however, the attempts to perturb Notch signaling pathways have been unsuccessful so far. In this study, we found that proteasome inhibitors exert cytotoxic effects on T-ALL cells with constitutive activation of Notch1 to a similar extent as myeloma cells. The proteasome inhibitor bortezomib repressed the transcription of Notch1 and downstream effectors including Hes1, GATA3, RUNX3 and nuclear factor-κB (NF-κB) (p65 and p50), coincided with downregulation of the major transactivator Sp1 and its dissociation from Notch1 promoter. Overexpression of the Notch1 intracellular domain (NICD) significantly ameliorated bortezomib-induced cytotoxicity against T-ALL cells. Drug combination studies revealed that bortezomib showed synergistic or additive effects with key drugs for the treatment of T-ALL such as dexamethasone (DEX), doxorubicin and cyclophosphamide, which were readily abolished by NICD overexpression. The synergy of bortezomib and DEX was confirmed in vivo using a murine xenograft model. Our findings provide a molecular basis and rationale for the inclusion of proteasome inhibitors in treatment strategies for T-ALL.
The usefulness of endobronchial ultrasonography (EBUS) with guide-sheath (GS) as a guide for transbronchial biopsy (TBB) for diagnosing peripheral pulmonary lesions (PPL)s and for improving ...diagnostic accuracy was evaluated in this study. EBUS-GS-guided TBB was performed in 24 patients with 24 PPLs of < or =30 mm in diameter (average diameter=18.4 mm). A 20-MHz radial-type ultrasound probe, covered with GS was inserted via a working bronchoscope channel and advanced to the PPL in order to produce an EBUS image. The probe with the GS was confirmed to reach the lesion by EBUS imaging and X-ray fluoroscopy. When the lesion was not identified on the EBUS image, the probe was removed and a curette was used to lead the GS to the lesion. After localising the lesion, the probe was removed, and TBB and bronchial brushing were performed via the GS. Nineteen peripheral lesions (79.2%) were visualised by EBUS. All patients whose PPLs were visible on EBUS images subsequently underwent an EBUS-GS-guided diagnostic procedure. A total of 14 lesions (58.3%) were diagnosed. Even when restricted to PPLs <20 mm in diameter, the diagnostic sensitivity was 53%. In conclusion, endobronchial ultrasonography with guide sheath-guided transbronchial biopsy was feasible and effective for diagnosing peripheral pulmonary lesions.
Lactobacillus reuteri is a heterofermentative lactic acid bacterium that naturally inhabits the gut of humans and other animals. The probiotic effects of L. reuteri have been proposed to be largely ...associated with the production of the broad-spectrum antimicrobial compound reuterin during anaerobic metabolism of glycerol. We determined the complete genome sequences of the reuterin-producing L. reuteri JCM 1112T and its closely related species Lactobacillus fermentum IFO 3956. Both are in the same phylogenetic group within the genus Lactobacillus. Comparative genome analysis revealed that L. reuteri JCM 1112T has a unique cluster of 58 genes for the biosynthesis of reuterin and cobalamin (vitamin B12). The 58-gene cluster has a lower GC content and is apparently inserted into the conserved region, suggesting that the cluster represents a genomic island acquired from an anomalous source. Two-dimensional nuclear magnetic resonance (2D-NMR) with 13C3-glycerol demonstrated that L. reuteri JCM 1112T could convert glycerol to reuterin in vivo, substantiating the potential of L. reuteri JCM 1112T to produce reuterin in the intestine. Given that glycerol is shown to be naturally present in feces, the acquired ability to produce reuterin and cobalamin is an adaptive evolutionary response that likely contributes to the probiotic properties of L. reuteri.
Multiple myeloma (MM) is incurable, mainly because of cell adhesion-mediated drug resistance (CAM-DR). In this study, we performed functional screening using short hairpin RNA (shRNA) to define the ...molecule(s) responsible for CAM-DR of MM. Using four bona fide myeloma cell lines (KHM-1B, KMS12-BM, RPMI8226 and U266) and primary myeloma cells, we identified CD29 (beta1-integrin), CD44, CD49d (alpha4-integrin, a subunit of VLA-4), CD54 (intercellular adhesion molecule-1 (ICAM-1)), CD138 (syndecan-1) and CD184 (CXC chemokine receptor-4 (CXCR4)) as major adhesion molecules expressed on MM. shRNA-mediated knockdown of CD49d but not CD44, CD54, CD138 and CD184 significantly reversed CAM-DR of myeloma cells to bortezomib, vincristine, doxorubicin and dexamethasone. Experiments using blocking antibodies yielded almost identical results. Bortezomib was relatively resistant to CAM-DR because of its ability to specifically downregulate CD49d expression. This property was unique to bortezomib and was not observed in other anti-myeloma drugs. Pretreatment with bortezomib was able to ameliorate CAM-DR of myeloma cells to vincristine and dexamethasone. These results suggest that VLA-4 plays a critical role in CAM-DR of MM cells. The combination of bortezomib with conventional anti-myeloma drugs may be effective in overcoming CAM-DR of MM.
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