Mantle cell lymphoma (MCL) is considered incurable. Intensive immunochemotherapy with stem cell support has not been tested in large, prospective series. In the 2nd Nordic MCL trial, we treated 160 consecutive, untreated patients younger than 66 years in a phase 2 protocol with dose-intensified induction immunochemotherapy with rituximab (R) ؉ cyclophosphamide, vincristine, doxorubicin, prednisone (maxi-CHOP), alternating with R ؉ highdose cytarabine. Responders received highdose chemotherapy with BEAM or BEAC (carmustine, etoposide, cytarabine, and melphalan/cyclophosphamide) with R-in vivo purged autologous stem cell support. Overall and complete response was achieved in 96% and 54%, respectively. The 6-year overall, event-free, and progressionfree survival were 70%, 56%, and 66%, respectively, with no relapses occurring after 5 years. Multivariate analysis showed Ki-67 to be the sole independent predictor of event-free survival. The nonrelapse mortality was 5%. The majority of stem cell products and patients assessed with polymerase chain reaction (PCR) after transplantation were negative. Compared with our historical control, the Nordic MCL-1 trial, the event-free, overall, and progression-free survival, the duration of molecular remission, and the proportion of PCR-negative stem cell products were significantly increased (P < .001). Intensive immunochemotherapy with in vivo purged stem cell support can lead to long-term progression-free survival of MCL and perhaps cure. Registered at www.isrctn.org as #ISRCTN 87866680.

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Determinants of di erentiation and apoptosis in myelomonocytic leukemia cells (U937) exposed to the novel hybrid polar compound SAHA (suberoylanilide hydroxamic acid) have been examined. In contrast to hexamethylenbisacetamide (HMBA), SAHA-related maturation was limited and accompanied by marked cytoxicity. SAHA-mediated apoptosis occurred within the G 0 G 1 and S phase populations, and was associated with decreased mitochondrial membrane potential, caspase-3 activation, PARP degradation, hypophosphorylation/cleavage of pRB, and down-regulation of c-Myc, c-Myb, and B-Myb. Enforced expression of Bcl-2 or Bclx L inhibited SAHA-induced apoptosis, but only modestly potentiated di erentiation. While SAHA induced the cyclin-dependent kinase inhibitor p21 CIP1 , antisense ablation of this CDKI increased, rather than decreased, SAHA-related lethality. In contrast, conditional expression of wild-type p53 failed to modify SAHA actions, but markedly potentiated HMBA-induced apoptosis. Finally, SAHA modestly increased expression/activation of the stress-activated protein kinase (SAPK/JNK); moreover, SAHA-related lethality was partially attenuated by a dominant-negative c-Jun mutant protein (TAM67). SAHA did not stimulate mitogen-activated protein kinase (MAPK), nor was lethality diminished by the speci®c MEK/MAPK inhibitor PD98059. These ®ndings indicate that SAHA potently induces apoptosis in human leukemia cells via a pathway that is p53-independent but at least partially regulated by Bcl-2/Bcl-x L , p21 CIP1 , and the c-Jun/AP-1 signaling cascade.

IntroductionTransforming growth factor beta (TGF-␤) is recognized as a highly pleiotropic family of growth factors involved in the regulation of numerous physiologic processes including development, hematopoiesis, wound healing, and immune response. The 3 isoforms of this growth factor that have been identified in mammals (TGF-␤1, -␤2, and -␤3) are encoded by distinct genetic loci and share a high level of homology. They act on virtually all cell types and mediate similar cellular responses in vitro, like regulation of proliferation, differentiation, apoptosis, and extracellular matrix synthesis. [1][2][3] In vivo, however, they demonstrate partly unique sets of physiologic functions due to different tissue distribution and temporal expression during development. [4][5][6] The TGF-␤ isoforms exert all their cellular functions through formation of a tetrameric complex with the 2 cell surface receptors T␤RI and T␤RII. Complex formation leads to phosphorylation of T␤RI on serine/threonine residues and propagation of the intracellular signal to the nucleus through a chain of phosphorylations of Smads, which regulate gene expression in cooperation with other transcription factors. 7 A growing body of evidence suggests TGF-␤ to be one of the major regulators of immune function, acting both by suppressive and stimulatory mechanisms on leukocytes to achieve a balanced immune response. [8][9][10] The suppressive mode of action has been highlighted by studies demonstrating inhibition of interleukin 1 (IL-1)-, IL-2-, and IL-7-dependent thymocyte proliferation by TGF-␤ 11-16 through autocrine and paracrine mechanisms, 13,17,18 whereas immunostimulatory functions were suggested by the capacity of TGF-␤ to induce cytokine expression in T cells and to promote effector expansion by inhibition of apoptosis. [19][20][21] Moreover, the influence of TGF-␤ on the development and function of other cells of the immune system, such as B cells, macrophages, and dendritic cells, has been reported. 10 Striking evidence for the importance of TGF-␤ in immune regulation was reported from studies on TGF-␤-null animals that demonstrated postnatal lethality and massive multifocal inflammation affecting multiple organs. 9,22,23 The uncontrolled inflammatory reaction has been ascribed to autoimmune mechanisms including autoantibodies and autoreactive T cells. [24][25][26][27] However, attempts to develop the phenotype by transplanting TGF-␤1-null bone marrow to healthy recipient mice unexpectedly resulted in minute inflammatory signs that did not cause clinical symptoms. 25 This raised the possibility that the presence of immune cells deficient for TGF-␤1 is not sufficient to cause the inflammatory phenotype. Alternatively, TGF-␤1-deficient donor cells may be responsive to endocrine or paracrine sources of TGF-␤1 produced by recipient tissues.Further evidence strongly suggests a role of TGF-␤ in the regulation of inflammation using dominant-negative transgenic For personal use only. on May 12, 2018. by guest www.bloodjournal.org From mouse models...

SummaryMantle cell lymphoma (MCL) is a heterogenic non-Hodgkin lymphoma entity, with a median survival of about 5 years. In 2008 we reported the early -based on the median observation time of 4 years -results of the Nordic Lymphoma Group MCL2 study of frontline intensive induction immunochemotherapy and autologous stem cell transplantation (ASCT), with more than 60% event-free survival at 5 years, and no subsequent relapses reported. Here we present an update after a median observation time of 6·5 years. The overall results are still excellent, with median overall survival and response duration longer than 10 years, and a median eventfree survival of 7·4 years. However, six patients have now progressed later than 5 years after end of treatment. The international MCL Prognostic Index (MIPI) and Ki-67-expression were the only independent prognostic factors. Subdivided by the MIPI-Biological Index (MIPI + Ki-67, MIPI-B), more than 70% of patients with low-intermediate MIPI-B were alive at 10 years, but only 23% of the patients with high MIPI-B. These results, although highly encouraging regarding the majority of the patients, underline the need of a risk-adapted treatment strategy for MCL. The study was registered at www.isrctn.org as ISRCTN 87866680.

Diamond-Blackfan anemia (DBA) is a congenital erythroid hypoplasia caused by a functional haploinsufficiency of genes encoding for ribosomal proteins. Among these genes, ribosomal protein S19 (RPS19) is mutated most frequently. Generation of animal models for diseases like DBA is challenging because the phenotype is highly dependent on the level of RPS19 down-regulation. We report the generation of mouse models for RPS19-deficient DBA using transgenic RNA interference that allows an inducible and graded down-regulation of Rps19. Rps19-deficient mice develop a macrocytic anemia together with leukocytopenia and variable platelet count that with time leads to the exhaustion of hematopoietic stem cells and bone marrow failure. Both RPS19 gene transfer and the loss of p53 rescue the DBA phenotype implying the potential of the models for testing novel therapies. This study demonstrates the feasibility of transgenic RNA interference to generate mouse models for human diseases caused by haploinsufficient expression of a gene. (Blood. 2011;118(23): 6087-6096) IntroductionDiamond-Blackfan anemia (DBA; Online Mendelian Inheritance in Man [OMIM] no. 105650) is a rare congenital erythroid hypoplasia that presents early in infancy. The classic hematologic profile of DBA consists of macrocytic anemia with selective absence of erythroid precursors in a normocellular bone marrow, normal or slightly decreased neutrophil, and variable platelet count. 1 During the course of the disease some patients show decreased bone marrow cellularity that often correlates with neutropenia and thrombocytopenia. 2 However, DBA is a developmental disease because ϳ 30%-47% of patients show a broad spectrum of physical abnormalities including craniofacial, heart, and upper limb malformations, and short stature. 1,[3][4][5] All known DBA disease genes encode for ribosomal proteins that collectively explain the genetic basis for ϳ 55% of DBA cases. [6][7][8][9][10][11] Twenty-five percent of the patients have mutations in a gene coding for ribosomal protein S19 (RPS19) making it the most common DBA gene. 6 The majority of the mutations completely disrupt the expression of the RPS19, whereas the rest are missense mutations interfering with the assembly of RPS19 into 40S ribosomal subunits. [12][13][14] All patients are heterozygous with respect to RPS19 mutations suggesting a functional haploinsufficiency of RPS19 as the basis for disease pathology.Despite of the recent advances in DBA genetics, the pathophysiology of the disease remains elusive. Cellular studies on patients together with successful marrow transplantation 15 have demonstrated the intrinsic nature of the hematopoietic defect. DBA patients have a variable deficit in burst-forming unit-erythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) progenitors with substantially reduced clonogenic output that correlates with the age of the patient. 2,16-19 A similar age-dependent decrease in granulocyte-macrophage progenitor (GMP) numbers has been reported. 20 Although present at normal freq...

Gaucher disease (GD) is an autosomal recessive lysosomal storage disorder caused by mutations in the glucosidase, beta, acid (GBA) gene that encodes the lysosomal enzyme glucosylceramidase (GCase). GCase deficiency leads to characteristic visceral pathology and, in some patients, lethal neurological manifestations. Here, we report the generation of mouse models with the severe neuronopathic form of GD. To circumvent the lethal skin phenotype observed in several of the previous GCase-deficient animals, we genetically engineered a mouse model with strong reduction in GCase activity in all tissues except the skin. These mice exhibit rapid motor dysfunction associated with severe neurodegeneration and apoptotic cell death within the brain, reminiscent of neuronopathic GD. In addition, we have created a second mouse model, in which GCase deficiency is restricted to neural and glial cell progenitors and progeny. These mice develop similar pathology as the first mouse model, but with a delayed onset and slower disease progression, which indicates that GCase deficiency within microglial cells that are of hematopoietic origin is not the primary determinant of the CNS pathology. These findings also demonstrate that normal microglial cells cannot rescue this neurodegenerative disease. These mouse models have significant implications for the development of therapy for patients with neuronopathic GD.lysosomal storage disorder ͉ glucocerebrosidase deficiency ͉ neurodegeneration ͉ knockout mice ͉ gene therapy

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