Haematologica 2004;89: supplement no. 6 - Supplements ...

104Postersand the intrinsic apoptotic pathways were triggeredby such treatment. CK2 blockade coupled withchemotherapeutics resulted in an additive cytotoxiceffect. Basal and TNFα dependent IkB degradation, aswell as NFkB transcriptional activity upon TNFα stimulationwere impaired by CK2 blockage in MM cells.A partial nuclear co-localization of the catalytic asubunit of CK2 and p50/p105 was observed by confocalmicroscopy in MM cells. Moreover, endogenousp50/p105 and CK2 could be immunoprecipitated inMM cell lines. We conclude d that CK2 is a kinase pivotalfor survival and proliferation of MM cells and itsselective blockade is strongly cytotoxic to malignantplasma cells. CK2 regulates IkB protein levels andNFkB transcriptional activity, this latter effect beingpossibly mediated through physical association withNFkB transcription factors. Our findings suggest thatthe CK2 inhibition could be exploited as a novel therapeuticapproach for MM.PO-067N-RAS AND K-RAS MUTATIONAL ANALYSIS IN NEWLYDIAGNOSED MULTIPLE MYELOMA PATIENTS: EVIDENCE FORTWO NOVEL ACTIVATING MUTATIONSoverini S, Cavo M, Tosi P, Terragna C, Zamagni E,Cellini C, Ottaviani E, Amabile M, Renzulli M, PoerioA, Grafone T, Cangini D, Tacchetti P, Tura S,Baccarani M, Martinelli GIstituto di Ematologia e Oncologia Medica "Seràgnoli",Università di Bologna, ItalyThe RAS family members are among the most commonlymutated oncogenes in multiple myeloma(MM). Activating mutations of N-RAS and K-RAShave been demonstrated to result in growth factorindependence and suppression of apoptosis of MMplasma cells. Nevertheless, the incidence and prognosticsignificance of RAS gene mutations in MM hasto date been reported with some discrepancies. Thisissue has now gained new interest since the recentdevelopment of novel anticancer drugs (such as thefarnesyl transferase inhibitors) acting by blockingoncogenic RAS-signaling pathway, which could besuccessfully exploited for the therapy of a subset ofMM patients. We investigated RAS gene mutations in85 newly diagnosed MM patients, who were randomizedto receive either a single or double autologousperipheral blood stem cell (PBSC) auto-transplant(s),following remission induction chemotherapywith VAD and high-dose cyclophosphamide. Forthis purpose, genomic DNA obtained from bone marrowsamples was analyzed by primer-specific amplificationof N- and K-RAS exons 1 and 2, followed bydirect automatic sequencing. We detected a total of31 point mutations in 30 out of 77 (39%) evaluablepatients. Nine mutations were found in N-RAS: oneat codon 12, two at codon 13 and six at codon61.Twenty-two mutations were found in K-RAS: eightat codon 12, four at codon 13, five at codon 16, twoat codon 31, two at codon 61.One patient showedevidence of two distinct K-RAS mutations (both atcodon 13 and at codon 61). To our knowledge, this isthe first time that K-RAS mutations at codons 16(AAG to AAC) and 31 (GAA to CAA) are reported inMM. To date, such mutations have been found onlyin adrenocortical tumors and have recently beendemonstrated as activating. No significant associationwas observed between any RAS mutation andage, gender, bone marrow infiltration, stage of disease,immunoglobulin isotype, creatinine, C-reactiveprotein and β-2-microglobulin levels. As far asresponse to treatment was concerned, no major differencesemerged between patients with and withouta mutated RAS gene. However, patients whoshowed mutations affecting K-RAS codons 12 and13 (n=12) had a significantly shorter event-free survival(EFS; median, 21 vs. 32 months; p = 0.03) withrespect to patients who did not (n=65). It is concludedthat: a) RAS activating mutations are a frequentevent (39%) in newly diagnosed MM patients;b) in our series of patients treated with high-dosechemotherapy and single or double PBSC autotransplant(s),K-RAS mutations at codons 12-13 are associatedto a worse outcome in terms of EFS, thus confirmingthe hypotesis that different RAS gene mutationscause a different degree of activation of thedownstream effector pathways. Analysis of a largerseries of patients is required to consider the impacton clinical outcome of the previously unreported K-RAS mutations at codon 16 and 31.Funding: This work was supported by University ofBologna, Progetti di Ricerca ex-60% (M. C. ); by MIURand FIRB projects; by COFIN 2003, by the Italian Associationfor Cancer Research (AIRC), by the Fondazionedel Monte di Bologna e Ravenna and by AIL.PO-068RANK/RANKL EXPRESSION IN MULTIPLE MYELOMA BONEMARROW ENVIRONMENT AND ITS ROLE IN IL-6 AND IL-11UP-REGULATIONColla S, Morandi F, Rizzoli V, Giuliani NCattedra di Ematologia, Università di Parma, ItalyThe receptor activator of NF-kB ligand (RANKL) hasa critical role in osteoclast activation. Recently it hasbeen demonstrated that human multiple myeloma(MM) cells up-regulate RANKL in human bone marrowstromal cells (BMSC). To further investigate therole of RANKL in the pathophysiology of MM we haveevaluated the expression of RANKL and its receptorhaematologica vol. 89[suppl. n. 6]:september 2004