Strategies to enhance the therapeutic efficacy of autologous hematopoietic stem cell transplantation by posttransplantation adoptive transfer of T cells with engineered graft-versus-tumor activity

Role of hematopoietic stem cell transplantation for advanced-stage diffuse large cell B-cell lymphoma-B

The prognosis of patients with relapsed or refractory diffuse large cell B-cell lymphoma-B (DLCL-B) is poor with conventional salvage chemotherapy; therefore, high-dose therapy (HDT) combined with autologous stem cell transplant (ASCT) has become the treatment of choice for these patients. The outcomes of transplant are better in patients with chemosensitive relapse: those with a longer duration of first remission (>12 month) and those with an age-adjusted low-risk International Prognostic Index (IPI) at relapse. Several high-dose regimens with or without total body irradiation (TBI) have been used with similar outcomes. Relapse remains the most common cause of treatment failure, and thus the use of radioimmunotherapy (RIT) in the high-dose regimens and incorporation of rituximab in the transplant setting have been explored. Several studies have shown that RIT both at conventional dose and at high dose can be given in combination with high-dose chemotherapy regimens without additional toxicity or delay in hematopoietic recovery after ASCT. Additional studies using RIT in combination with high-dose chemotherapy and ASCT are ongoing, and preliminary results suggest that these approaches may be superior to conventional high-dose regimens. Since rituximab is an effective therapy for B-cell non-Hodgkin's lymphoma and given its limited toxicity, rituximab has been incorporated into HDT and ASCT for DLCL-B as in vivo purging, as part of high-dose regimens, and as maintenance therapy to prevent relapse. Preliminary results suggested that rituximab during ASCT and as maintenance therapy post-transplant reduces the risk of relapse and improves survival; however, these results need to be confirmed in phase III randomized trials. The role of ASCT during first remission as consolidative therapy in patients with DLCL-B remains controversial and should not be performed outside of the clinical trial setting. Allogeneic stem cell transplant (allo-SCT) for patients with relapsed DLCL-B is associated with significant toxicity and should be reserved for patients who relapse after ASCT or those with persistent marrow involvement. Innovative approaches are needed for primary refractory and chemoresistant relapsed DLCL-B since these patients have very poor outcomes after ASCT.

Current status of genetic modification of T cells for cancer treatment

Clinical studies of adoptive immunotherapy with T cells have shown activity directed at hematologic and solid malignancies and viral infections. Genetic modification of infused T cells offers the prospect of improving such therapies and has already been used to track infused T cells, insert suicide genes and redirect the immune response towards specific Ag. Pre-clinical studies are evaluating novel approaches to genetically modify T cells to confer resistance to tumor evasion mechanisms. There is also increasing interest in developing suicide gene strategies as a failsafe mechanism to eradicate genetically modified cells should adverse effects occur.

Development and evaluation of a micro- and nanoscale proteomic sample preparation method

Challenges associated with the efficient and effective preparation of micro- and nanoscale (micro- and nanogram) clinical specimens for proteomic applications include the unmitigated sample losses that occur during the processing steps. Herein, we describe a simple "single-tube" preparation protocol appropriate for small proteomic samples using the organic cosolvent, trifluoroethanol (TFE) that circumvents the loss of sample by facilitating both protein extraction and protein denaturation without requiring a separate cleanup step. The performance of the TFE-based method was initially evaluated by comparisons to traditional detergent-based methods on relatively large scale sample processing using human breast cancer cells and mouse brain tissue. The results demonstrated that the TFE-based protocol provided comparable results to the traditional detergent-based protocols for larger, conventionally sized proteomic samples (>100 microg protein content), based on both sample recovery and numbers of peptide/protein identifications. The effectiveness of this protocol for micro- and nanoscale sample processing was then evaluated for the extraction of proteins/peptides and shown effective for small mouse brain tissue samples (approximately 30 microg total protein content) and also for samples of approximately 5000 MCF-7 human breast cancer cells (approximately 500 ng total protein content), where the detergent-based methods were ineffective due to losses during cleanup and transfer steps.