A novel antitumor protein, designated RE26, with anti-lymphoma activity was purified from a Tris-HCl buffer extract of Rozites emodensis (Berk.) Moser by three successive steps of ion exchange chromatography. SDS-PAGE and gel filtration chromatography revealed that RE26 is a monomeric protein of 26 kDa, and isoelectrofocusing assay indicated its isoelectric point of 4.3-4.4. RE26 has high stability over a wide pH range (pH 3-11) but is sensitive to temperature and only stable under 40 °C. Partial amino acid sequences of two RE26 peptide fragments were determined by Edman degradation as GLEEEETLLLLFFPP and GTEQE. The half-maximal inhibitory concentration (IC₅₀) of RE26 against tested lymphoma cell lines was around 4 μg/ml. In vitro experiments showed that RE26 could specifically bind to lymphoma cells; activate the caspases, including caspases 3, 8, and 9 in host cells; and induce apoptosis. Experiments in nude mice indicated local RE26 injection adjacent to tumor site could inhibit lymphoma formation.

Combination therapies are often needed for effective clinical outcomes in the management of complex diseases, but presently they are generally based on empirical clinical experience. Here we suggest a novel application of search algorithms -- originally developed for digital communication -- modified to optimize combinations of therapeutic interventions. In biological experiments measuring the restoration of the decline with age in heart function and exercise capacity in Drosophila melanogaster, we found that search algorithms correctly identified optimal combinations of four drugs using only one-third of the tests performed in a fully factorial search. In experiments identifying combinations of three doses of up to six drugs for selective killing of human cancer cells, search algorithms resulted in a highly significant enrichment of selective combinations compared with random searches. In simulations using a network model of cell death, we found that the search algorithms identified the optimal combinations of 6-9 interventions in 80-90% of tests, compared with 15-30% for an equivalent random search. These findings suggest that modified search algorithms from information theory have the potential to enhance the discovery of novel therapeutic drug combinations. This report also helps to frame a biomedical problem that will benefit from an interdisciplinary effort and suggests a general strategy for its solution.

Chemotherapy with ifosfamide, epirubicin and etoposide (IEV) is an effective treatment regimen for refractory/relapsed non-Hodgkin lymphoma (NHL). Rituximab has been shown to improve response rates, progression-free survival and overall survival in B-cell NHL. This study included 85 patients who were treated with IEV or rituximab-IEV (R-IEV) for refractory/relapsed B-cell NHL. The overall response rate was 40.7% (IEV) versus 68.8% (R-IEV). Fever occurred after 23.4% of IEV and 19.4% of R-IEV cycles. 94.9% of patients mobilized sufficient numbers of CD34+ cells (IEV) versus 93.8% (R-IEV). Fifty-five patients (64.7%) proceeded to high-dose therapy after IEV+/-rituximab. The median survival time was 60.0 months (IEV) and 19.5 months (R-IEV), and has not been reached for patients who received high-dose therapy. The addition of rituximab to IEV salvage chemotherapy increases the response rates in B-cell NHL without affecting stem cell mobilization, but overall survival for patients proceeding to high-dose chemotherapy is not improved.

To date little data exist about treatment of hematologic malignancies in patients with end-stage renal disease (ESRD). While administration of immunochemotherapy comprising the CD20-antibody rituximab is a well-established treatment strategy in patients with normal renal function, little information on safety and efficacy is available in the setting of ESRD. Here we describe for the first time a hemodialysis patient suffering from diffuse large B-cell Non-Hodgkin's lymphoma (DLBCL) who was treated with polychemotherapy (cyclophosphamide, doxorubicin, vincristine and prednisone) in combination with rituximab (R-CHOP). We observed no major adverse events and treatment resulted in a partial remission of the DLBCL. Thus, administration of R-CHOP may be considered as a safe therapeutic option in this setting. Of note, this patient had a previous history of hairy cell leukemia. A review of the literature was performed and the potential etiologic link of these two B-cell malignancies is discussed in the light of available information.

Targeted immunotherapy utilizing monoclonal antibodies has improved survival in both indolent and aggressive lymphoma significantly. Since malignant lymphomas are also responsive to radiation, the combination of targeted immunotherapy and radiation with radionuclide coupled to monoclonal antibodies is an attractive option to further improve treatment results. Zevalin is a commercially available variation of the murine anti-CD20 antibody ibritumomab coupled to Yttrium 90 via the tiuxetan chelator. The development of this novel drug as well as the results of the pivotal studies and clinical strategies to implement this treatment into the routine practice of lymphoma oncology are presented in this review.

Rituximab (chimeric anti-CD20 monoclonal antibody) is the first Food and Drug Administration approved antitumor antibody and is used in the treatment of B-non-Hodgkin's lymphoma (B-NHL). It is used as single monotherapy or in combination with chemotherapy and has improved the treatment outcome of patients with B-NHL. The in vivo mechanisms of rituximab-mediated antitumor effects include antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cell cytotoxicity (CDC), growth-inhibition and apoptosis. A subset of patients does not initially respond to rituximab and several responsive patients develop resistance to further rituximab treatment. The mechanism of rituximab unresponsiveness is not known. Besides the above-postulated mechanisms, rituximab has been shown to trigger the cells via CD-20. Studies performed with B-NHL cell lines as model systems revealed several novel mechanisms of rituximab-mediated effects that are involved in chemo/immunosensitization and the development of resistance to rituximab. Rituximab has been shown to inhibit the p38 mitogen-activated protein kinase, nuclear factor-kappaB (NF-kappaB), extracellular signal-regulated kinase 1/2 (ERK 1/2) and AKT antiapoptotic survival pathways, all of which result in upregulation of phosphatase and tensin homolog deleted on chromosome ten and Raf kinase inhibitor protein and in the downregulation of antiapoptotic gene products (particularly Bcl-2, Bcl-(xL) and Mcl-1), and resulting in chemo/immunosensitization. Further, rituximab treatment inhibits the overexpressed transcription repressor Yin Yang 1 (YY1), which negatively regulates Fas and DR5 expression and its inhibition leads to sensitization to Fas ligand and tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis. Rituximab-resistant clones were generated as model to examine the mechanism of in vivo rituximab unresponsiveness. These clones showed reduced expression of CD20 and hyperactivation of the above antiapoptotic signaling pathways and failure of rituximab to trigger the cells leading to inhibition of ADCC, CDC and chemo/immunosensitization. Interference with the hyperactivated pathways with various pharmacological and proteasome inhibitors reversed resistance. Furthermore, the above findings have identified several gene products that can serve as new prognostic/diagnostic biomarkers as well as targets for therapeutic intervention in B-NHL.

Non-Hodgkin lymphoma (NHL), a malignancy that manifests in the lymphatic system, is one of the most commonly occurring hematologic disease types in the United States and other Westernized countries. NHL is divided into a range of subtypes with differing clinical features and outcomes. Depending on the type of NHL and the patient's overall clinical presentation, treatment varies from systemic combined chemotherapy regimens with or without immunotherapy, radioimmunotherapy, and transplants to investigational options. Oncology nurses play a vital role in implementing successful treatment and management of patients with NHL as oncology care moves into an era of novel targeted therapies.

Recommended first-line treatment for posttransplant lymphoproliferative disorder (PTLD) is reduction in immunosuppressive therapy, irrespective of histopathological type. Second-line treatment with chemotherapy is generally reserved for tumors that fail to respond to reduced immunosuppression. In view of the similarities between monomorphic PTLD and non-Hodgkin's lymphoma in the general population, our policy is to treat monomorphic PTLD with anthracycline-based chemotherapy as first-line treatment.

A retrospective single-center analysis of 18 adults who developed PTLD following liver or kidney transplantation was undertaken, with particular emphasis on tumor histology, treatment received, and clinical outcome.

Of the 18 patients with PTLD, 13 had high-grade malignant lymphoma on diagnostic biopsy and received anthracycline-based chemotherapy and reduction in immunosuppression as first-line therapy. Nine (69%) of the 13 patients achieved complete remission and eight (62%) remained in complete remission five years after diagnosis. There was no graft loss from rejection or drug toxicity. Four (22%) patients had polymorphic PTLD on diagnostic biopsy (of which two were re-classified as monomorphic) and one had a low-grade malignant lymphoma. All five patients were treated by reduction in immunosuppression without chemotherapy and were in complete remission at a median of two years after diagnosis. Overall, complete remission was seen in 14 out of 18 patients (78%) at one year following diagnosis.

The use of anthracycline-based chemotherapy and reduction of immunosuppression as first-line treatment in adults with monomorphic PTLD is well tolerated and achieves sustained complete remission in around 70% of patients with a low risk of graft loss.

The incidence of non-Hodgkin's lymphoma (NHL) has markedly increased in the US and other westernized countries in recent years and presents a considerable clinical challenge. NHL is divided into subtypes that follow an aggressive or indolent course. Follicular lymphoma (FL), the most common indolent subtype, and mantle cell lymphoma (MCL), an aggressive subtype that accounts for approximately 5% of cases, are generally incurable. MCL has a relatively poor prognosis, with a median survival of 3-4 years. Despite improving response rates with new agents and regimens, the lack of demonstrated improvement in overall survival in many subtypes supports the development of novel approaches, such as proteasome inhibition. Bortezomib is the first proteasome inhibitor to be evaluated in human studies. It has already been approved as second-line treatment in multiple myeloma and is now under active investigation in NHL. The US FDA has granted bortezomib fast-track designation for relapsed and refractory MCL. In vitro and in vivo studies have demonstrated single-agent activity against various lymphoid tumors, and additive or synergistic effects in combination with other agents, including standard chemotherapy drugs employed in NHL. Phase 2 clinical trials indicate that bortezomib is well tolerated and active in several NHL subtypes, with response rates of 18-60% in FL and 39-56% in MCL. A number of combination trials are currently underway with a range of standard agents. Bortezomib has the potential to play a significant role throughout the NHL treatment algorithm in the future.

High-dose therapy (HDT) for non-Hodgkins lymphoma (NHL) and multiple myeloma (MM) is considered a feasible option for patients aged 60 years. This study compared the outcomes for all patients aged 60 years treated with HDT at the center to a matched cohort group aged <60 years. Results for patients who were 60 years at HDT between 1997--2002 were retrospectively analysed to assess efficacy and safety. Event-free (EFS) and overall survival (OS) rates were compared with a cohort group, matched by disease type, chemotherapy sensitivity, year of treatment and conditioning regimen. Patients with NHL were also matched by International Prognostic Index score. Forty patients aged 60 years were identified. Median age was 65 (range 60--76) with 22 MM and 18 NHL; 50% had 1 or more co-morbidity; 35% had cardiovascular co-morbidity vs. 18% of controls (p=0.075). Response rates (RR) following HDT for MM were: 4 (18%) complete responses (CR) and 18 (82%) partial responses (PR), giving an overall response rate (ORR) of 100%, vs. 77% for controls (p=0.02). For NHL patients there were: 8 CR (44%) and 4 PR (22%), giving an ORR of 67%, vs. 83% for controls (p=0.3). Transplant-related mortality was 8% compared to 5% in controls (p=0.6). Toxicities were similar with the exception of cardiac toxicity, which was significantly higher in patients aged 60 years vs. controls (50% grade 3 vs. 10%: p<0.0001). Atrial fibrillation was the most frequent cardiovascular toxicity (9 patients). At a median follow-up of 33 months, there is no significant difference between older vs. younger patients in median EFS (24 vs. 38 months: p=0.78) or OS (40 months vs. not reached: p=0.23). HDT is feasible and effective in selected patients 60 years with MM and NHL. Patients 60 years are more susceptible to cardiovascular toxicities, particularly atrial fibrillation, but have similar or better response rates following HDT and similar long-term outcomes to younger patients.

Forty patients with relapsed diffuse large B cell lymphoma (DLBCL) autografted in partial response (PR) (n = 23) or in refractory relapse (RR) (n = 17) achieved complete remission (CR) after autologous stem cell transplantation (ASCT). Salvage treatment consisted of ifosphamide, epirubicin and etoposide (IEV) in 33 patients and Cisplatinum, ARA-C and dexamethasone (DHAP) in 7 patients. All PR and 8 RR patients were conditioned with BEAM, while 9 RR cases received the BCV regimen. There were no significant differences between the two groups as age, serum LDH, duration of CR1 and IPI at relapse are concerned. Relapse rate after ASCT was 39% in PR group as opposed to 88% in RR group (p = 0.003). Median relapse free survival from ASCT was 6 months for RR patients as opposed to 34 months for PR patients (p = 0.003); median overall survival from ASCT was 10 months for RR subset as opposed to not reached for RR subgroup (p = 0.001). These data demonstrate that CR achieved after ASCT in DLBCL patients who are refractory to previous salvage therapy does not result in long-term disease control. Alternative preparative regimens, allogeneic SCT and/or monoclonal antibodies in the post-ASCT phase should be considered for RR patients despite CR achievement.

Less than 50% of all high-grade non-Hodgkin lymphoma (NHL) patients experience lasting disease-free survival. Risk-adapted treatment strategies require better tools for prediction of outcome. This investigation aimed to assess the value of positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose (FDG-PET) after two to three cycles of chemotherapy for prediction of progression-free survival (PFS) and overall survival (OS).

One hundred and twenty-one patients with high-grade NHL underwent FDG-PET. The therapy response on FDG-PET was correlated to PFS and OS using Kaplan-Meier survival analysis. Cox regression analyses were employed to test for independence of known pretreatment prognostic factors.

Fifty FDG-PET scans were negative, 19 scans showed minimal residual uptake (MRU), and 52 scans were positive. The estimated 5 year PFS was 88.8% for the PET-negative group, 59.3% for the MRU group, and 16.2% for the PET-positive group. Kaplan-Meier analyses showed strong associations between FDG-PET results and PFS (P <0.0001) and OS (P <0.01). Early interim FDG-PET was independent of the other prognostic factors.

Early interim FDG-PET is an accurate and independent predictor of PFS and OS. An early assessment of chemotherapy response with FDG-PET could provide the basis for selection of patients for alternative therapeutic strategies.

We investigated the apoptosis gene expression profile of chronic lymphocytic leukemia (CLL) cells in relation to (1) normal peripheral and tonsillar B-cell subsets, (2) IgV(H) mutation status, and (3) effects of cytotoxic drugs. In accord with their noncycling, antiapoptotic status in vivo, CLL cells displayed high constitutive expression of Bcl-2 and Flip mRNA, while Survivin, Bid and Bik were absent. Paradoxically, along with these antiapoptotic genes CLL cells had high-level expression of proapoptotic BH3-only proteins Bmf and Noxa. Treatment of CLL cells with fludarabine induced only the proapoptotic genes Bax and Puma in a p53-dependent manner. Interestingly, the degree of Puma induction was more pronounced in cells with mutated IgVH genes. Thus, disturbed apoptosis in CLL is the net result of both protective and sensitizing aberrations. This delicate balance can be tipped via induction of Puma in a p53-dependent matter, the level of which may vary between groups of patients with a different tendency for disease progression.

The clinical application of rituximab (chimeric mouse anti-human CD20 mAb, Rituxan, IDEC-C2B8), alone and/or combined with chemotherapy, has significantly ameliorated the treatment outcome of patients with relapsed and refractory low-grade or follicular non-Hodgkin's lymphoma (NHL). The exact in vivo mechanisms of action of rituximab are not fully understood, although antibody-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and apoptosis have been suggested. We have proposed that modifications of the cellular signaling pathways by rituximab may be crucial for its clinical response. The B-cell restricted cell surface phosphoprotein CD20 is involved in many cellular signaling events including proliferation, activation, differentiation, and apoptosis upon crosslinking. Monomeric rituximab chemosensitizes drug-resistant NHL cells via selective downregulation of antiapoptotic factors through the type II mitochondrial apoptotic pathway. Several signaling pathways are affected by rituximab which are implicated in the underlying molecular mechanisms of chemosensitization. ARL (acquired immunodeficiency syndrome (AIDS)-related lymphoma) and non-ARL cell lines have been examined as in vitro model systems. In ARL, rituximab diminishes the activity of the p38MAPK signaling pathway resulting in inhibition of the interleukin (IL)-10/IL-10R autocrine/paracrine cytokine autoregulatory loop leading to the inhibition of constitutive STAT-3 activity and subsequent downregulation of Bcl-2 expression leading to chemosensitization. Rituximab upregulates Raf-1 kinase inhibitor protein (RKIP) expression in non-ARL cells. Through physical association with Raf-1 and nuclear factor kappaB (NF-kappa B)-inducing kinase (NIK), RKIP negatively regulates two major survival pathways, namely, the extracellular signal-regulated kinase1/2 (ERK1/2) and the NF-kappa B pathways, respectively. Downmodulation of the ERK1/2 and NF-kappa B pathways inhibits the transcriptional activity of AP-1 and NF-kappa B transcription factors, respectively, both of which lead to the downregulation of Bcl-(xL) (Bcl-2 related gene (long alternatively spliced variant of Bcl-x gene)) transcription and expression and sensitization to drug-induced apoptosis. Bcl-(xL)-overexpressing cells corroborated the pivotal role of Bcl-(xL) in chemosensitization. The specificity of rituximab-mediated signaling and functional effects were corroborated by the use of specific pharmacological inhibitors. Many patients do not respond and/or relapse and the mechanisms of unresponsiveness are unknown. Rituximab-resistant B-NHL clones were generated to investigate the acquired resistance to rituximab-mediated signaling, and chemosensitization. Resistant clones display different phenotypic, genetic and functional properties compared to wild-type cells. This review summarizes the data highlighting a novel role of rituximab as a signal-inducing antibody and as a chemosensitizing agent through negative regulation of major survival pathways. Studies presented herein also reveal several intracellular targets modified by rituximab, which can be exploited for therapeutic and prognostic purposes in the treatment of patients with rituximab- and drug-refractory NHL.