Adam Lerner

Final Results From a Multicenter, International, Pivotal Study of Romidepsin in Refractory Cutaneous T-Cell Lymphoma

PURPOSE The primary objective of this study was to confirm the efficacy of romidepsin in patients with treatment refractory cutaneous T-cell lymphoma (CTCL). PATIENTS AND METHODS This international, pivotal, single-arm, open-label, phase II study was conducted in patients with stage IB to IVA CTCL who had received one or more prior systemic therapies. Patients received romidepsin as an intravenous infusion at a dose of 14 mg/m(2) on days 1, 8, and 15 every 28 days. Response was determined by a composite assessment of total tumor burden including cutaneous disease, lymph node involvement, and blood (Sézary cells). RESULTS Ninety-six patients were enrolled and received one or more doses of romidepsin. Most patients (71%) had advanced stage disease (≥ IIB). The response rate was 34% (primary end point), including six patients with complete response (CR). Twenty-six of 68 patients (38%) with advanced disease achieved a response, including five CRs. The median time to response was 2 months, and the median duration of response was 15 months. A clinically meaningful improvement in pruritus was observed in 28 (43%) of 65 patients, including patients who did not achieve an objective response. Median duration of reduction in pruritus was 6 months. Drug-related adverse events were generally mild and consisted mainly of GI disturbances and asthenic conditions. Nonspecific, reversible ECG changes were noted in some patients. CONCLUSION Romidepsin has significant and sustainable single-agent activity (including improvement in pruritus) and an acceptable safety profile, making it an important therapeutic option for treatment refractory CTCL.

p130Cas Regulates the Activity of AND-34, a Novel Ral, Rap1, and R-Ras Guanine Nucleotide Exchange Factor

We previously identified a novel murine protein, AND-34, with a carboxyl-terminal domain homologous to Ras family guanine nucleotide exchange factors (GEFs), which bound to the focal adhesion docking protein p130Cas. Work by others has implicated both the human homologue of AND-34, BCAR3, and human p130Cas, BCAR1, in the resistance of breast cancer cells to the anti-estrogen tamoxifen. Here we report that AND-34 displays GEF activity on RalA, Rap1A, and R-Ras but not Ha-Ras GTPases in cells. In contrast to several other Ral-GEFs, the Ral GEF activity of AND-34 is not augmented by constitutively active Ha-RasVal-12, consistent with the absence of a detectable Ras-binding domain. Efficient binding to AND-34 required both the Src-binding domain and a flanking carboxyl-terminal region of p130Cas. The p130Cas-binding site mapped to a carboxyl-terminal sequence within the AND-34 GEF domain. Overexpression of p130Cas, but not an AND-34-binding mutant of p130Cas, inhibited the Ral GEF activity of co-transfected AND-34. This work identifies a new potential function for p130Cas and a new regulatory pathway involved in the control of Ral, Rap, and R-Ras GTPases that may participate in the progression of breast cancer cells to tamoxifen resistance.

Cyclic nucleotide phosphodiesterases as targets for treatment of haematological malignancies

The cAMP signalling pathway has emerged as a key regulator of haematopoietic cell proliferation, differentiation and apoptosis. In parallel, general understanding of the biology of cyclic nucleotide PDEs (phosphodiesterases) has advanced considerably, revealing the remarkable complexity of this enzyme system that regulates the amplitude, kinetics and location of intracellular cAMP-mediated signalling. The development of therapeutic inhibitors of specific PDE gene families has resulted in a growing appreciation of the potential therapeutic application of PDE inhibitors to the treatment of immune-mediated illnesses and haematopoietic malignancies. This review summarizes the expression and function of PDEs in normal haematopoietic cells and the evidence that family-specific inhibitors will be therapeutically useful in myeloid and lymphoid malignancies.

The cAMP Signaling Pathway as a Therapeutic Target in Lymphoid Malignancies

Certain subsets of lymphoid cells, such as thymocytes or peripheral B cells, undergo apoptosis after treatment with agents which elevate intracellular 3,5 cyclic adenosine monophosphate (cAMP). Investigators have also noted induction of apoptosis of chronic lymphocytic leukemia (CLL) cells following treatment with methylxanthines, a phenomenon that may, at least in part, be due to the activity of these drugs as non-specific phosphodiesterase (PDE) inhibitors. We discuss three general strategies for altering cAMP-mediated signal transduction in lymphoid cells. After a review of what is known about the expression and regulation of PDE families in human lymphoid cells, we focus on the use of isoform-specific PDE inhibitors as potential therapeutic agents in CLL. Our work has suggested that despite the presence of PDE1, PDE3B, PDE4 and PDE7 enzymes in CLL, inhibition of PDE4 results in uniquely potent induction of apoptosis in CLL cells. This effect is relatively specific as comparable treatment of human peripheral blood T cells does not induce apoptosis. Clinical trials utilizing PDE4 inhibitors are indicated in the therapy of CLL patients resistant to standard therapy.

A Phase II trial of Belinostat (PXD101) in patients with relapsed or refractory peripheral or cutaneous T-cell lymphoma

Belinostat is a pan‐histone deacetylase inhibitor with antitumour and anti‐angiogenic properties. An open label, multicentre study was conducted in patients with peripheral T‐cell lymphoma (PTCL) or cutaneous T‐cell lymphoma (CTCL) who failed ≥1 prior systemic therapy and were treated with belinostat (1000 mg/m2 intravenously ×5 d of a 21‐d cycle). The primary endpoint was objective response rate (ORR). Patients with PTCL (n = 24) had received a median of three prior systemic therapies (range 1–9) and 40% had stage IV disease. Patients with CTCL (n = 29) had received a median of one prior skin‐directed therapy (range 0–4) and four prior systemic therapies (range 1–9); 55% had stage IV disease. The ORRs were 25% (PTCL) and 14% (CTCL). Treatment‐related adverse events occurred in 77% of patients; nausea (43%), vomiting (21%), infusion site pain (13%) and dizziness (11%) had the highest incidence. Treatment‐related serious adverse events were Grade 5 ventricular fibrillation; Grade 4 thrombocytopenia; Grade 3 peripheral oedema, apraxia, paralytic ileus and pneumonitis; and Grade 2 jugular vein thrombosis. Belinostat monotherapy was well tolerated and efficacious in patients with recurrent/refractory PTCL and CTCL. This trial was registered at www.clinicaltrials.gov as NCT00274651.

Cardiac Output Monitoring: Is There a Gold Standard and How Do the Newer Technologies Compare?

As a principal determinant of oxygen delivery and of blood pressure, cardiac output (CO) represents an important hemodynamic variable. Its accurate measurement, therefore, is important to the clinician caring for critically ill patients in a variety of care environments. Though the first clinical measurement of CO occurred 70 years ago, it was the introduction of the pulmonary artery catheter (PAC) with thermodilution-based determination of CO in the 1970s that set the stage for practical and widespread clinical measurement of CO. Although the usefulness and accuracy of this technique have justified its consideration as a “practical” gold standard in CO measurement, its drawbacks have driven the search for newer, less invasive measurement techniques. The last decade has seen the introduction of several such devices into the clinical arena. This article will serve to give a brief review of the history of CO measurement, to provide a discussion of the measurement of accuracy as it relates to CO measurement, and to discuss some of the newer methods and devices for CO measurement and how they have fared against a “practical” gold standard.

Cross-linking of T-cell receptors on double-positive thymocytes induces a cytokine-mediated stromal activation process linked to cell death.

To investigate molecular events associated with the intrathymic process of negative selection, we established an in vivo system using an anti‐CD3 epsilon monoclonal antibody to induce synchronous apoptosis in the thymus of AND T‐cell receptor (TCR) transgenic RAG‐2−/− mice in a non‐selecting haplotype. This model eliminates endogenous negative selection as well as gene activation in the mature thymocyte compartment, offering an ideal source of tester (anti‐CD3 epsilon‐treated) and driver (untreated) thymus RNA for representational difference analysis (RDA). Fourteen mRNA sequences that are up‐regulated in the thymuses of such mice 2–6 h after anti‐CD3 epsilon treatment were identified. Surprisingly, the majority of these transcripts were derived from stromal cells rather than the TCR‐cross‐linked CD4+CD8+TCRlow thymocytes including the macrophage products IL‐1, the chemokine Mig and the transcription factor LRG‐21. IFN‐gamma secretion from the CD4+CD8+TCRlow thymocytes regulates macrophage Mig production. Three other cytokines (IL‐4, GM‐CSF and TNF‐alpha), known to activate a variety of stromal cells, are also induced in the same thymocyte population undergoing apoptosis. Expression of a TNF‐alpha‐inducible gene, B94, in stromal cells after TCR ligation further supports the notion of cross‐talk between thymocytes and stroma. Thus, TCR‐triggered immature thymocytes elaborate cytokines which may regulate the delivery of further signals from stromal cells required for apoptosis.

Four cases of cardiopulmonary thromboembolism during liver transplantation without the use of antifibrinolytic drugs

Orthotopic liver transplantation (OLT) is one of the most demanding surgical procedures performed. Intraoperative bleeding can be substantial and related to both surgical and nonsurgical causes. A less common but previously reported phenomenon is intraoperative cardiopulmonary thromboembolism precipitating major patient morbidity and mortality. In this paper, we present four cases of intraoperative thromboembolism during OLT. These cases were performed without the concomitant use of antifibrinolytic drugs. We performed a review and analysis of previously reported cases of intraoperative thromboembolism during OLT. Possible causes of thromboembolism, clinical management, use of thromboelastography, and the role of antifibrinolytic drugs are discussed.

The GDP Exchange Factor AND-34 Is Expressed in B Cells, Associates With HEF1, and Activates Cdc42

AND-34, a novel GDP exchange factor, is expressed constitutively at significant levels in murine splenic B cells, but not in murine splenic T cells or thymocytes. In B cell lines, anti-IgM treatment up-regulates AND-34 transcript levels. B cell AND-34 associates with both the docking molecules p130Cas and HEF1. AND-34 binds by its GDP exchange factor domain to the C terminus of HEF1, a region of HEF1 previously implicated in apoptotic, adhesion, and cell cycle-regulated signaling. Overexpression of AND-34 in murine B cell lines activates the Rho family GTPase Cdc42, but not Rac, Rho, RalA, or Rap1. Consistent with this, a subpopulation of AND-34 overexpressing B cells have long filamentous actin-containing cellular extensions. AND-34 overexpression augments both autophosphorylation and kinase activity of the Cdc42/Rac-responsive serine/threonine kinase PAK1. As previously reported for lymphoid cells transfected with constitutively active Cdc42, AND-34 overexpression inhibits SDF-1α-induced B cell polarization. These studies suggest that p130Cas and HEF1-associated AND-34 may regulate B cell adhesion and motility through a Cdc42-mediated signaling pathway.

CD40 Ligand-mediated Activation of the de Novo RelB NF-κB Synthesis Pathway in Transformed B Cells Promotes Rescue from Apoptosis

CD40, a tumor necrosis factor receptor family member, is expressed on B lymphocytes. Interaction between CD40 and its ligand (CD40L), expressed on activated T lymphocytes, is critical for B cell survival. Here, we demonstrate that CD40 signals B cell survival in part via transcriptional activation of the RelB NF-κB subunit. CD40L treatment of chronic lymphocytic leukemia cells induced levels of relB mRNA. Similarly, CD40L-mediated rescue of WEHI 231 B lymphoma cells from apoptosis induced upon B cell receptor (surface IgM) engagement led to increased relB mRNA levels. Recently, we characterized a new de novo synthesis pathway for the RelB NF-κB subunit, induced by the cytomegalovirus IE1 protein, in which binding of p50/p65 NF-κB and c-Jun/Fra-2 AP-1 complexes to the relB promoter works in synergy to potently activate transcription (Wang, X., and Sonenshein, G. E. (2005) J. Virol. 79, 95–105). CD40L treatment of WEHI 231 cells caused induction of AP-1 family members Fra-2, c-Jun, JunD, and JunB. Cotransfection of Fra-2 with the Jun AP-1 subunits and p50/c-Rel NF-κB led to synergistic activation of the relB promoter. Ectopic expression of relB or RelB knockdown using small interfering RNA demonstrated the important role of this subunit in control of WEHI 231 cell survival and implicated activation of the anti-apoptotic factors Survivin and manganese superoxide dismutase. Thus, CD40 engagement of transformed B cells activates relB gene transcription via a process we have termed the de novo RelB synthesis pathway, which protects these cells from apoptosis.