Antonio Gutiérrez

Deletions Affecting Codons 557-558 of the c-KIT Gene Indicate a Poor Prognosis in Patients With Completely Resected Gastrointestinal Stromal Tumors: A Study by the Spanish Group for Sarcoma Research (GEIS)

PURPOSEnTo explore the prognostic value of mutations in c-KIT and PDGFR-alpha genes with respect to relapse-free survival (RFS) in patients with gastrointestinal stromal tumors (GIST). We have investigated the prognostic relevance of the type and position of the mutations, in addition to other clinicopathologic factors, in a large series of patients with GIST.nnnMETHODSnFor this study, 162 patients were selected according to the following criteria: completely resected tumors with negative margins attended between 1994 and 2001; no metastasis at diagnosis; tumor larger than 2 cm, c-KIT-positive immunostaining; and no other primary tumors.nnnRESULTSnThe median follow-up was 42 months for patients free of recurrence. Mutations were detected in 96 tumors (60%): 82 cases involving c-KIT and 14 cases involving PDFGR-alpha. Univariate analysis demonstrated the following as poor prognostic factors for RFS: tumors larger than 10 cm (P < .0001); mitotic count higher than 10 mitoses per 50 high-power fields (P < .0001); high risk index (P < .0001); intestinal GIST location (P = .0041); high cellularity (P < .0001); tumor necrosis (P < .0001); deletions affecting exon 11 (P = .0007); and deletions affecting codons 557 to 558 (P < .0001). After the multivariate analysis, only the high risk index (relative risk [RR], 12.36), high cellularity (RR, 3.97), and deletions affecting codons 557 to 558 of c-KIT (RR, 2.57) corresponded to independent prognostic factors for RFS in GIST patients.nnnCONCLUSIONnDeletions affecting codons 557 to 558 are relevant for the prognosis of RFS in GIST patients. This critical genetic alteration should be considered to be a new prognostic stratification variable for randomized trials exploring imatinib mesylate in the adjuvant setting in GIST patients.

Frontline autologous stem cell transplantation in high-risk peripheral T-cell lymphoma: a prospective study from The Gel-Tamo Study Group

Objective:u2002 Retrospective data shows that peripheral T‐cell lymphoma (PTCL) patients sensitive to conventional chemotherapy for aggressive lymphomas may respond better if this treatment is consolidated with frontline autologous stem cell transplantation (ASCT). Here, we present data from a prospective phase II trial of high‐dose chemotherapy and ASCT as a frontline consolidation therapy for aggressive nodal PTCL.

GEMOX‐R regimen is a highly effective salvage regimen in patients with refractory/relapsing diffuse large‐cell lymphoma: a phase II study

Objectives:u2002 The prognosis of old or immunocompromised patients with refractory or relapsing diffuse large‐cell lymphoma (DLCL) is very poor as the current standard of salvage therapy with autologous stem cell transplantation (ASCT) is not feasible for most of them. New active regimens with an acceptable toxicity profile are needed. We aim to report the results of a phase II trial of the GEMOX‐R regimen in DLCL.

Prolonged survival of patients with angioimmunoblastic T‐cell lymphoma after high‐dose chemotherapy and autologous stem cell transplantation. The GELTAMO experience

Objectives:u2002 Angioimmunoblastic T‐cell lymphoma (AIL) is a rare lymphoma with a poor prognosis and no standard treatment. Here, we report our experiences with 19 patients treated with high‐dose chemotherapy and autologous stem cell transplantation (HDC/ASCT) within the GELTAMO co‐operative group between 1992 and 2004.

Rituximab, gemcitabine and oxaliplatin: An effective regimen in patients with refractory and relapsing mantle cell lymphoma

Mantle cell lymphoma constitutes one of the lymphomas with poorest prognosis at relapse with limited effective salvage regimens due to advanced age. We present results of a new salvage regimen, rituximab, gemcitabine and oxaliplatin (GEMOX-R), in 14 patients with relapsing (n = 9) or refractory (n = 5) mantle cell lymphoma. The median number of cycles was 5.5 for a total of 72 cycles evaluated in the current study. The median age was 69.5 years with high-risk features. Patients received a mean number of prior treatment lines of 1.79. Sixty-four percent achieved CR (total response rate of 85%). With a median follow-up of 11 months, OS and PFS were 58% and 45% at 12 months. The major toxicity was thrombopenia grade III-IV (35%). Factors related with overall survival were ECOG performance status and a-IPI at GEMOX-R. We conclude that GEMOX-R displays an outstanding efficacy with an excellent toxicity profile in a pretreated elderly population.

Minerval induces apoptosis in Jurkat and other cancer cells.

Minerval is an oleic acid synthetic analogue that impairs lung cancer (A549) cell proliferation upon modulation of the plasma membrane lipid structure and subsequent regulation of protein kinase C localization and activity. However, this mechanism does not fully explain the regression of tumours induced by this drug in animal models of cancer. Here we show that Minerval also induced apoptosis in Jurkat T‐lymphoblastic leukaemia and other cancer cells. Minerval inhibited proliferation of Jurkat cells, concomitant with a decrease of cyclin D3 and cdk2 (cyclin‐dependent kinase2). In addition, the changes that induced on Jurkat cell membrane organization caused clustering (capping) of the death receptor Fas (CD95), caspase‐8 activation and initiation of the extrinsic apoptosis pathway, which finally resulted in programmed cell death. The present results suggest that the intrinsic pathway (associated with caspase‐9 function) was activated downstream by caspase‐8. In a xenograft model of human leukaemia, Minerval also inhibited tumour progression and induced tumour cell death. Studies carried out in a wide variety of cancer cell types demonstrated that apoptosis was the main molecular mechanism triggered by Minerval. This is the first report on the pro‐apoptotic activity of Minerval, and in part explains the effectiveness of this non‐toxic anticancer drug and its wide spectrum against different types of cancer.

Primary mediastinal large cell lymphoma (PMBL): frontline treatment with autologous stem cell transplantation (ASCT). The GEL‐TAMO experience

Given the excellent results obtained with present new induction regimens in PMBL, the role of frontline ASCT is controversial. We present 71 patients with PMBL receiving induction chemotherapy, followed by ASCT as frontline therapy from the GEL‐TAMO registry. Most patients presented with high‐risk clinical features. At transplant, 49% of patients were in CR, 32% in PR and 18% failed induction therapy; 53% received radiotherapy. After the transplant 75% of patients achieved CR. With a median follow‐up of 52.5 months, the OS, PFS and DFS at 4 years from diagnosis were, respectively, 84%, 81% and 81% for the first CR patients and 49%, 42% and 82% for the induction failure (PR and refractory) patients. Disease progression was the main cause of death (79%). By multivariate survival analysis the tumour score, refractory disease at transplant and radiotherapy were independent variables associated with OS and PFS. Our experience, with a prolonged follow‐up, shows that patients with PMBL presenting at diagnosis with high‐risk features or PR response to induction therapy have an encouraging survival with frontline ASCT. However, patients who received the transplant after failing the induction regimen have a very poor prognosis and should be tested with other innovative approaches. Finally, only a randomized trial could prove the value of ASCT as frontline therapy and also must be considered that addition to Rituximab to induction treatments could make ASCT unnecessary. Copyright

Nilotinib Counteracts P-Glycoprotein-Mediated Multidrug Resistance and Synergizes the Antitumoral Effect of Doxorubicin in Soft Tissue Sarcomas

The therapeutic effect of doxorubicin (DXR) in the treatment of soft tissue sarcomas (STS) is limited by its toxicity and the development of multidrug resistance (MDR), the latter mainly induced by high expression of efflux pumps (e.g., P-glycoprotein [P-gp]). Therefore, the search for alternative therapies, which sensitize these tumors to chemotherapy while maintaining a low toxicity profile, is a rational approach. We assessed efficacy and molecular mechanisms involved in the antiproliferative effects of the tyrosine kinase inhibitors, nilotinib and imatinib, as single agents or in combination with DXR, in human synovial sarcoma SW982 and leiomyosarcoma SK-UT-1 cells. As single compound nilotinib (1–10 µM) was more potent than imatinib inhibiting the growth of SK-UT-1 and SW982 cells by 33.5–59.6%, respectively. Importantly, only nilotinib synergized the antitumoral effect of DXR (0.05–0.5 µM) by at least 2-fold, which clearly surpassed the mere sum of effects according to isobolographic analysis. Moreover, nilotinib in combination with DXR had a sustained effect on cell number (−70.3±5.8%) even 12 days after withdrawal of drugs compared to DXR alone. On the molecular level, only nilotinib fully blocked FBS-induced ERK1 and p38 MAPK activation, hence, reducing basal and DXR-induced up-regulation of P-gp levels. Moreover, efflux activity of the MDR-related proteins P-gp and MRP-1 was inhibited, altogether resulting in intracellular DXR retention. In high-risk STS tumors 53.8% and 15.4% were positive for P-gp and MRP-1 expression, respectively, with high incidence of P-gp in synovial sarcoma (72.7%). In summary, nilotinib exhibits antiproliferative effects on cellular models of STS and sensitizes them to DXR by reverting DXR-induced P-gp-mediated MDR and inhibiting MRP-1 activity, leading to a synergistic effect with potential for clinical treatment.

Pharmacokinetic properties of rituximab.

Rituximab is a mouse/human chimeric IgG1kappa monoclonal antibody that targets the CD20 antigen found on the surface of malignant and normal B-lymphocytes. The mechanisms of action of rituximab involve complement-dependent cytotoxicity (CDC), complement-dependent cellular cytotoxicity (CDCC), antibody dependent cellular cytotoxicity (ADCC) and induction of apoptosis. Pharmacokinetic issues, tumor and molecular related factors mediate resistance to rituximab. Optimizing rituximab treatment requires a therapeutic project that might ideally be individualized and that includes enhancing of ADCC and CDC mechanisms, acting over apoptosis-regulating proteins and using synergistic conventional chemotherapeutic agents. Pharmacokinetic favourable schedules in specific diseases alone or associated to chemotherapeutic agents are not well known, therefore studies focusing on these issues are warranted. New information regarding targeting the lymphoma microenvironment and rituximab effects is the focus of current research.

Inhibition of c-Myc Down-Regulation by Sustained Extracellular Signal-Regulated Kinase Activation Prevents the Antimetabolite Methotrexate- and Gemcitabine-Induced Differentiation in Non-Small-Cell Lung Cancer Cells

Non-small-cell lung cancer (NSCLC) is characterized by severe resistance to chemotherapy. Here, we demonstrate that A549 adenocarcinoma cells permanently differentiate with the antimetabolites methotrexate (MTX) and gemcitabine (GE) when blocking the resistance mechanism that normally counteracts this process. MTX (1-10 μM) and GE (1 μM) induced growth arrest accompanied by sustained extracellular signal-regulated kinase (ERK1/2) phosphorylation and moderate reduction of c-Myc levels after 96 h, whereas only a low percentage of the cells differentiated. Combination with the mitogen-activated protein kinase kinase (MEK) inhibitor 1,4-diamino-2,3-dicyano-1,4-bis-(methylthio)butadiene (U0126) reduced MTX- or GE-induced ERK1/2 over-phosphorylation, nearly abolished c-Myc expression, and provoked radical morphological changes in all cells. Besides the appearance of multilamellar bodies and intracellular cytokeratin reorganization, modulation of molecular markers occurred in a manner consistent with differentiation (gelsolin, +300%; surfactant protein A and C, -70%). Similar to U0126, c-Myc inactivation with specific small interfering RNA initiated differentiation only in the presence of MTX, demonstrating that inhibition of the mitogen-activated protein kinase/ERK pathway alone or down-regulation of c-Myc is not sufficient to induce this process. It is noteworthy that withdrawal of antitumoral drugs and U0126 neither reversed differentiation nor reactivated proliferation. Our results reveal that maintenance of a certain threshold of c-Myc expression through sustained ERK1/2 activation represents a molecular mechanism that confers resistance to antimetabolite-induced differentiation in A549 cells, and provide a novel molecular basis for therapeutic strategies based on irreversible differentiation of cancer cells using conventional chemotherapeutic antimetabolites in combination with inhibitors of the MEK/ERK pathway or c-Myc.