Dysregulation of global microRNA expression in splenic marginal zone lymphoma and influence of chronic hepatitis C virus infection.
Leukemia. 2012 Feb 6;
Authors: Peveling-Oberhag J, Crisman G, Schmidt A, Döring C, Lucioni M, Arcaini L, Rattotti S, Hartmann S, Piiper A, Hofmann WP, Paulli M, Küppers R, Zeuzem S, Hansmann ML
Abstract
The precise molecular pathogenesis of splenic marginal zone lymphoma (SMZL) is still unknown. Clinical and epidemiologic data suggest that chronic hepatitis C virus (HCV) infection may play an etiological role in a subset of cases. We performed a large-scale miRNA expression profiling analysis of 381 miRNAs by quantitative reverse-transcription PCR (Q-RT-PCR) of 26 microdissected splenic tissue samples (7 HCV(+) SMZL; 8 HCV(-) SMZL and 11 non-neoplastic splenic controls). Single assay Q-RT-PCR and miRNA in situ hybridisation were used to confirm the results in an independent cohort. Unsupervised hierarchical clustering of miRNA expression profiles demonstrated a distinct signature of SMZL compared to the normal splenic marginal zone. Supervised analysis revealed differentially expressed miRNAs, including miRNAs with previously recognized tumor suppressive or oncogenic potential. Five miRNAs were found significantly overexpressed in SMZL, including miR-21, miR-155, and miR-146a, while seven miRNAs showed significantly reduced expression, including miR-139, miR-345, miR-125a, and miR-126. Furthermore, we identified miR-26b, a miRNA known to have tumor suppressive properties, as significantly downregulated in SMZL arising in HCV positive patients (P=0.0016). In conclusion, there is a characteristic dysregulation of miRNA expression in SMZL with a possible implication in its molecular tumorigenesis.Leukemia accepted article preview online, 6 February 2012; doi:10.1038/leu.2012.29.
PMID: 22307176 [PubMed - as supplied by publisher]
Standardization of flow cytometry in myelodysplastic syndromes: a report from an international consortium and the European leukemianet working group.
Leukemia. 2012 Feb 6;
Authors: Westers TM, Ireland R, Kern W, Alhan C, Balleisen JS, Bettelheim P, Burbury K, Cullen M, Cutler JA, Della Porta MG, Dräger AM, Feuillard J, Font P, Germing U, Haase D, Johansson U, Kordasti S, Loken MR, Malcovati L, Te Marvelde JG, Matarraz S, Milne T, Moshaver B, Mufti GJ, Ogata K, Orfao A, Porwit A, Psarra K, Richards SJ, Subirá D, Tindell V, Vallespi T, Valent P, van der Velden VH, de Witte TM, Wells DA, Zettl F, Béné MC, van de Loosdrecht AA
Abstract
Flow cytometry (FC) is increasingly recognized as an important tool in the diagnosis and prognosis of myelodysplastic syndromes (MDS). However, validation of current assays and agreement upon the techniques are prerequisites for its widespread acceptance and application in clinical practice. Therefore, a working group was initiated (Amsterdam, 2008) to discuss and propose standards for FC in MDS. In 2009 and 2010, representatives from 23, mainly European, institutes participated in the 2nd and 3rd European LeukemiaNet (ELN) MDS workshops. In the present report, minimal requirements to analyze dysplasia are refined. The proposed core markers should enable a categorization of FC results in cytopenic patients as “normal”, “suggestive of” or “diagnostic of” MDS. A FC report should include a description of validated FC abnormalities such as aberrant marker expression on myeloid progenitors and, furthermore, dysgranulopoiesis and/or dysmonocytopoiesis if at least two abnormalities are evidenced. The working group is dedicated to initiate further studies to establish robust diagnostic and prognostic FC panels in MDS. An ultimate goal is to refine and improve diagnosis and prognostic scoring systems. Finally, the working group stresses that FC should be part of an integrated diagnosis, rather than a separate technique.Leukemia accepted article preview online, 6 February 2012; doi:10.1038/leu.2012.30.
PMID: 22307178 [PubMed - as supplied by publisher]
Preclinical activity of LBH589 alone or in combination with chemotherapy in a xenogeneic mouse model of human acute lymphoblastic leukemia.
Leukemia. 2012 Feb 6;
Authors: Vilas-Zornoza A, Agirre X, Abizanda G, Moreno C, Segura V, De Martino Rodriguez A, José-Eneriz ES, Miranda E, Martín-Subero JI, Garate L, Blanco-Prieto MJ, Jalón JG, Rio P, Rifón J, Cigudosa JC, Martinez-Climent JA, Román-Gómez J, Calasanz MJ, Ribera JM, Prósper F
Abstract
Histone deacetylases (HDACs) have been identified as therapeutic targets due to their regulatory function in chromatin structure and organization. Here we analyzed the therapeutic effect of LBH589, a class I-II HDAC inhibitor, in acute lymphoblastic leukemia (ALL). In vitro, LBH589 induced dose-dependent antiproliferative and apoptotic effects, which were associated with increased H3 and H4 histone acetylation. Intravenous (i.v.) administration of LBH589 in immunodeficient BALB/c-RAG2(-/-)γc(-/-) mice in which human-derived T and B-ALL cell lines were injected induced a significant reduction in tumor growth. Using primary ALL cells, a xenograft model of human leukemia in BALB/c-RAG2(-/-)γc(-/-) mice was established, allowing continuous passages of transplanted cells to several mouse generations. Treatment of mice engrafted with T or B-ALL cells with LBH589 induced an in vivo increase in the acetylation of H3 and H4, which was accompanied with prolonged survival of LBH589-treated mice in comparison with those receiving Vincristine and Dexametasone. Notably, the therapeutic efficacy of LBH589 was significantly enhanced in combination with Vincristine and Dexametasone. Our results demonstrate the therapeutic activity of LBH589 in combination with standard chemotherapy in pre-clinical models of ALL and suggest that this combination may be of clinical value in the treatment of patients with ALL.Leukemia accepted article preview online, 6 February 2012; doi:10.1038/leu.2012.31.
PMID: 22307227 [PubMed - as supplied by publisher]
Consequences of heat shock protein 72 (Hsp72) expression and activity on stress-induced apoptosis in CD30(+) NPM-ALK(+) anaplastic large-cell lymphomas.
Leukemia. 2012 Jan 6;
Authors: Bonvini P, Zorzi E, Mussolin L, Pillon M, Romualdi C, Peron M, d’Amore ES, Lamant L, Rosolen A
Abstract
Understanding the mechanisms that control stress-induced apoptosis is critical to explain how tumours respond to treatment, as cancer cells frequently escape drug toxicity by regulating stress response through heat shock protein (HSP) expression. The overexpression of Hsp72, in particular, results in increased incidence of cell transformation, and correlates with poor prognosis in a wide range of cancers. We have shown that Hsp72 assists folding of oncogenic NPM-ALK kinase in anaplastic large-cell lymphomas (ALCLs), but its role in the maintenance of the malignant phenotype remains uncertain. Therefore, we assessed Hsp72 expression in ALCLs, investigating more in detail the mechanisms that regulate its status and activity. We found that Hsp72 is unique among the HSPs involved in tumourigenesis to be overexpressed in ALK(+) tumours and cell lines and to be induced by stress. Different from other HSPs, Hsp72 prevents cell injury, Bax activation and death by apoptosis in ALK(+) cells, acting both upstream and downstream of mitochondria. Conversely, Hsp72 is underexpressed in ALK(-) ALCL cells, and it is unable to protect cells from apoptosis under stress. Moreover, when Hsp72 expression is reduced following NPM-ALK inhibition, lymphoma cells undergo apoptosis, demonstrating the importance of Hsp72 in regulating ALCL stress response and drug sensitivity.Leukemia advance online publication, 6 January 2012; doi:10.1038/leu.2011.367.
PMID: 22289917 [PubMed - as supplied by publisher]
The CD49d/CD29 complex is physically and functionally associated with CD38 in B-cell chronic lymphocytic leukemia cells.
Leukemia. 2012 Jan 6;
Authors: Zucchetto A, Vaisitti T, Benedetti D, Tissino E, Bertagnolo V, Rossi D, Bomben R, Dal Bo M, Del Principe MI, Gorgone A, Pozzato G, Gaidano G, Del Poeta G, Malavasi F, Deaglio S, Gattei V
Abstract
CD49d and CD38 are independent negative prognostic markers in chronic lymphocytic leukemia (CLL). Their associated expression marks a disease subset with a highly aggressive clinical course. Here, we demonstrate a constitutive physical association between the CD49d/CD29 integrin complex and CD38 in primary CLL cells and B-cell lines by (i) cocapping, (ii) coimmunoprecipitation and (iii) cell adhesion experiments using CD49d-specific substrates (vascular-cell adhesion molecule-1 or CS-1/H89 fibronectin fragments). The role of CD38 in CD49d-mediated cell adhesion was studied in CD49d(+)CD38(+) and CD49d(+)CD38(-) primary CLL cells, and confirmed using CD38 transfectants of the originally CD49d(+)CD38(-) CLL-derived cell line Mec-1. Results indicate that CD49d(+)CD38(+) cells adhered more efficiently onto CD49d-specific substrates than CD49d(+)CD38(-) cells (P<0.001). Upon adhesion, CD49d(+)CD38(+) cells underwent distinctive changes in cell shape and morphology, with higher levels of phosphorylated Vav-1 than CD49d(+)CD38(-) cells (P=0.0006) and a more complex distribution of F-actin to the adhesion sites. Lastly, adherent CD49d(+)CD38(+) cells were more resistant to serum-deprivation-induced (P<0.001) and spontaneous (P=0.03) apoptosis than the CD49d(+)CD38(-) counterpart. Altogether, our results point to a direct role for CD38 in enhancing CD49d-mediated adhesion processes in CLL, thus providing an explanation for the negative clinical impact exerted by these molecules when coexpressed in neoplastic cells.Leukemia advance online publication, 6 January 2012; doi:10.1038/leu.2011.369.
PMID: 22289918 [PubMed - as supplied by publisher]
Monoclonal antibodies against ROR1 induce apoptosis of chronic lymphocytic leukemia (CLL) cells.
Leukemia. 2012 Jan 6;
Authors: Daneshmanesh AH, Hojjat-Farsangi M, Khan AS, Jeddi-Tehrani M, Akhondi MM, Bayat AA, Ghods R, Mahmoudi AR, Hadavi R, Osterborg A, Shokri F, Rabbani H, Mellstedt H
Abstract
ROR1 is a receptor tyrosine kinase (RTK) recently identified to be overexpressed at the gene and protein levels in chronic lymphocytic leukemia (CLL). Monoclonal antibodies (MAbs) against RTKs have been successfully applied for therapy of solid tumors. We generated five MAbs against the Ig (n=1), cysteine-rich (CRD) (n=2) and kringle (KNG) (n=2) domains, respectively, of the extracellular part of ROR1. All CLL patients (n=20) expressed ROR1 on the surface of the leukemic cells. A significantly higher frequency of ROR1 expression was found in patients with progressive versus non-progressive disease, and in those with unmutated versus mutated IgVH genes. All five MAbs alone induced apoptosis in the absence of complement or added effector cells (Annexin-V and MTT, as well as cleavage of poly-(ADP ribose)-polymerase, caspase-8 and caspase-9) of CLL cells but not of normal B cells. Most effective were MAbs against CRD and KNG, significantly superior to rituximab (P<0.005). Cross-linking of anti-ROR1 MAbs using the F(ab’)(2) fragments of anti-Fc antibodies significantly augmented apoptosis. Two of the MAbs induced complement-dependent cytotoxicity (CDC) similar to that of rituximab and one anti-ROR1 MAb (KNG) (IgG1) showed killing activity by antibody-dependent cellular cytotoxicity. The identified ROR1 epitopes may provide a basis for generating human ROR1 MAbs for therapy.Leukemia advance online publication, 6 January 2012; doi:10.1038/leu.2011.362.
PMID: 22289919 [PubMed - as supplied by publisher]
Loss-of-function mutations within the IL-2 inducible kinase ITK in patients with EBV-associated lymphoproliferative diseases.
Leukemia. 2012 Jan 6;
Authors: Linka RM, Risse SL, Bienemann K, Werner M, Linka Y, Krux F, Synaeve C, Deenen R, Ginzel S, Dvorsky R, Gombert M, Halenius A, Hartig R, Helminen M, Fischer A, Stepensky P, Vettenranta K, Köhrer K, Ahmadian MR, Laws HJ, Fleckenstein B, Jumaa H, Latour S, Schraven B, Borkhardt A
Abstract
The purpose of this study was the appraisal of the clinical and functional consequences of germline mutations within the gene for the IL-2 inducible T-cell kinase, ITK. Among patients with Epstein-Barr virus-driven lymphoproliferative disorders (EBV-LPD), negative for mutations in SH2D1A and XIAP (n=46), we identified two patients with R29H or D500T,F501L,M503X mutations, respectively. Human wild-type (wt) ITK, but none of the mutants, was able to rescue defective calcium flux in murine Itk(-/-) T cells. Pulse-chase experiments showed that ITK mutations lead to varying reductions of protein half-life from 25 to 69% as compared with wt ITK (107 min). The pleckstrin homology domain of wt ITK binds most prominently to phosphatidylinositol monophosphates (PI(3)P, PI(4)P, PI(5)P) and to lesser extend to its double or triple phosphorylated derivates (PIP2, PIP3), interactions which were dramatically reduced in the patient with the ITK(R29H) mutant. ITK mutations are distributed over the entire protein and include missense, nonsense and indel mutations, reminiscent of the situation in its sister kinase in B cells, Bruton’s tyrosine kinase.Leukemia advance online publication, 6 January 2012; doi:10.1038/leu.2011.371.
PMID: 22289921 [PubMed - as supplied by publisher]
