Therese White

The lymph node microenvironment promotes B-cell receptor signaling, NF-κB activation, and tumor proliferation in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL), an incurable malignancy of mature B lymphocytes, involves blood, bone marrow, and secondary lymphoid organs such as the lymph nodes (LN). A role of the tissue microenvironment in the pathogenesis of CLL is hypothesized based on in vitro observations, but its contribution in vivo remains ill-defined. To elucidate the effects of tumor-host interactions in vivo, we purified tumor cells from 24 treatment-naive patients. Samples were obtained concurrently from blood, bone marrow, and/or LN and analyzed by gene expression profiling. We identified the LN as a key site in CLL pathogenesis. CLL cells in the LN showed up-regulation of gene signatures, indicating B-cell receptor (BCR) and nuclear factor-κB activation. Consistent with antigen-dependent BCR signaling and canonical nuclear factor-κB activation, we detected phosphorylation of SYK and IκBα, respectively. Expression of BCR target genes was stronger in clinically more aggressive CLL, indicating more effective BCR signaling in this subtype in vivo. Tumor proliferation, quantified by the expression of the E2F and c-MYC target genes and verified with Ki67 staining by flow cytometry, was highest in the LN and was correlated with clinical disease progression. These data identify the disruption of tumor microenvironment interactions and the inhibition of BCR signaling as promising therapeutic strategies in CLL. This study is registered at http://clinicaltrials.gov as NCT00019370.

Vaccine-induced tumor-specific immunity despite severe B-cell depletion in mantle cell lymphoma

The role of B cells in T-cell priming is unclear, and the effects of B-cell depletion on immune responses to cancer vaccines are unknown. Although results from some mouse models suggest that B cells may inhibit induction of T cell–dependent immunity by competing with antigen-presenting cells for antigens, skewing T helper response toward a T helper 2 profile and/or inducing T-cell tolerance, results from others suggest that B cells are necessary for priming as well as generation of T-cell memory. We assessed immune responses to a well-characterized idiotype vaccine in individuals with severe B-cell depletion but normal T cells after CD20-specific antibody–based chemotherapy of mantle cell lymphoma in first remission. Humoral antigen- and tumor-specific responses were detectable but delayed, and they correlated with peripheral blood B-cell recovery. In contrast, vigorous CD4+ and CD8+ antitumor type I T-cell cytokine responses were induced in most individuals in the absence of circulating B cells. Analysis of relapsing tumors showed no mutations or change in expression of target antigen to explain escape from therapy. These results show that severe B-cell depletion does not impair T-cell priming in humans. Based on these results, it is justifiable to administer vaccines in the setting of B-cell depletion; however, vaccine boosts after B-cell recovery may be necessary for optimal humoral responses.

Treatment-Induced Oxidative Stress and Cellular Antioxidant Capacity Determine Response to Bortezomib in Mantle Cell Lymphoma

Purpose: Proteasome inhibition disrupts protein homeostasis and induces apoptosis. Up to 50% of patients with relapsed mantle cell lymphoma (MCL) respond to bortezomib. We used gene expression profiling to investigate the connection between proteasome inhibition, cellular response, and clinical efficacy. Experimental Design: We assessed transcriptional changes in primary tumor cells from five patients during treatment with bortezomib in vivo, and in 10 MCL cell lines exposed to bortezomib in vitro, on Affymetrix microarrays. Key findings were confirmed by western blotting. Results: MCL cell lines exposed to bortezomib in vitro showed upregulation of endoplasmic reticulum and oxidative stress response pathways. Gene expression changes were strongest in bortezomib-sensitive cells and these cells were also more sensitive to oxidative stress induced by H2O2. Purified tumor cells obtained at several timepoints during bortezomib treatment in 5 previously untreated patients with leukemic MCL showed strong activation of the antioxidant response controlled by NRF2. Unexpectedly, activation of this homeostatic program was significantly stronger in tumors with the best clinical response. Consistent with its proapoptotic function, we found upregulation of NOXA in circulating tumor cells of responding patients. In resistant cells, gene expression changes in response to bortezomib were limited and upregulation of NOXA was absent. Interestingly, at baseline, bortezomib-resistant cells displayed a relatively higher expression of the NRF2 gene-expression signature than sensitive cells (P < 0.001). Conclusion: Bortezomib triggers an oxidative stress response in vitro and in vivo. High cellular antioxidant capacity contributes to bortezomib resistance. Clin Cancer Res; 17(15); 5101–12. ©2011 AACR.

Lymphomatoid Granulomatosis—A Single Institute Experience Pathologic Findings and Clinical Correlations

Lymphomatoid granulomatosis (LYG) is a rare angiocentric and angiodestructive Epstein-Barr virus (EBV)-associated B-cell lymphoproliferative disorder. It is hypothesized that these patients have dysregulated immune surveillance of EBV. We reviewed the biopsies of 55 patients with LYG who were referred for a prospective trial at the National Cancer Institute (1995 to 2010) and evaluated the histologic, immunohistochemical, in situ hybridization, and molecular findings of these biopsies in conjunction with clinical information. Grading of the lesions was based on morphologic features and the number of EBV-positive B cells. The median age was 46 years (M:F 2.2:1). Clinically, all patients had lung involvement (100%), with the next most common site being the central nervous system (38%). No patient had nodal or bone marrow disease. All patients had past EBV exposure by serology but with a low median EBV viral load. We reviewed 122 biopsies; the most common site was lung (73%), followed by skin/subcutaneous tissue (17%); other sites included kidney, nasal cavity, gastrointestinal tract, conjunctiva, liver, and adrenal gland. Histologically, the lesions showed angiocentricity, were rich in T cells, had large atypical B cells, and were positive for EBV. Grading was performed predominantly on the lung biopsy at diagnosis; they were distributed as follows: LYG grade 1 (30%), grade 2 (22%), and grade 3 (48%). Necrosis was seen in all grades, with a greater degree in high-grade lesions. Immunoglobulin gene rearrangement studies were performed, and a higher percentage of clonal rearrangements were seen in LYG grade 2 (50%) and grade 3 (69%) as compared with grade 1 (8%). LYG is a distinct entity that can usually be differentiated from other EBV-associated B-cell lymphoproliferative disorders on the basis of the combination of clinical presentation, histology, and EBV studies. Grading of these lesions is important because it dictates the treatment choice.

Phase I trial of 7-hydroxystaurosporine and fludararbine phosphate: in vivo evidence of 7-hydroxystaurosporine induced apoptosis in chronic lymphocytic leukemia

Abstract This is a phase I study of 7-hydroxystaurosporine (UCN-01) and fludararbine monophosphate (FAMP) in relapsed lymphoma. UCN-01 alone was administered in cycle 1 and with FAMP in cycles 2–6. FAMP was escalated in cohorts from 1 to 5 days. UCN-01 and FAMP pharmacokinetics and apoptosis of malignant lymphocytes was evaluated. Eighteen patients were enrolled. Standard FAMP with UCN-01 was tolerated without dose-limiting toxicity (DLT) and those seen were common to either agent alone. One patient died due to Stevens-Johnson syndrome. Seven of 18 patients responded. No pharmacological effect of UCN-01 by FAMP was noted. Lymphocytosis occurred in 15 of 18 patients following UCN-01 to paradoxically increase circulating tumor cells. UCN-01 induced apoptosis in six of eight patients with chronic lymphocytic leukemia (CLL). UCN-01 does not increase FAMP toxicity. Transient lymphocytosis followed by apoptosis occurs with UCN-01. Mobilization from tissue reservoirs may play a role in the induction of cell death in malignant lymphocytes.

Albumin enhanced morphometric image analysis in CLL.

The heterogeneity of lymphocytes from patients with chronic lymphocytic leukemia (CLL) and blood film artifacts make morphologic subclassification of this disease difficult.

Immunophenotypic Features Distinguishing Familial Chronic Lymphocytic Leukemia from Sporadic Chronic Lymphocytic Leukemia

Familial chronic lymphocytic leukemia (CLL) has the most frequent familial aggregation among hematological malignancies. Familial CLL families have been studied to identify susceptibility genes and other factors that contribute in the etiology of CLL. To date no study has been conducted to evaluate and compare patterns of cell surface antigen expression in familial CLL and sporadic CLL.

Phase II study of EPOCH infusional chemotherapy in relapsed or refractory Hodgkin's lymphoma (HL). A report on toxicity, efficacy and prognostic indicators of outcome

6598 Background: In relapsed/refractory HL, an effective and well tolerated salvage regimen has important roles both prior to autologous stem cell transplant (SCT) and as palliative therapy in patients (pts) who are ineligible for or have failed SCT. METHODS Eligible pts had relapsed/refractory HL and adequate organ function unless due to HL. Pts received fixed dose EPOCH chemotherapy (etoposide 200 mg/m2, vincristine 1.6 mg/m2 (no cap) and doxorubicin 40 mg/m2 CIVI x 96-hrs D1-4; cyclophosphamide 750 mg/m2 IV D5 and prednisone 60 mg/m2 qd D1-6 ) with G-CSF q21 days until disease progression or stabilization over ≥ 2 cycles. RESULTS Of 54 pts, median (range) age was 31 yrs (19-64), 35 (66%) were male, stage was III in 11(21%) and IV in 30(56%), and 29 (55%) had B symptoms. Histology included nodular sclerosis 34 (64%), mixed cellularity 3 (25%), and lymphocyte depleted 5 (9%) classical HL, and nodular lymphocyte predominant HL 1 (2%). 24 (45%) pts had had ≥ 2 prior regimens, 27 (51%) pts received chemotherapy within the previous 10 mos, and 40 (75%) pts had responded to their last treatment. Over 202 cycles, toxicities included fever and neutropenia on 9 (4%), grade (gr) 4 neutropenia on 31 (15%), gr 4 thrombocytopenia on 20 (10%), and ≥ gr 2 gastrointestinal toxicity on 20 (10%) cycles; ≥ gr 2 cardiotoxicity occurred in 2 (4%) and ≥ gr 2 neurotoxicity in 11 (20%) pts. There was one treatment related death. 45 (84%) pts responded with 23 (44%) CR and 21 (40%) PR. With a median follow-up of 68 mos, the median progression-free (PFS) and overall survivals (OS) are 10 and 40 mos, and at 68 mos median follow-up, PFS and OS are 21% and 41%. Among 33 pts who underwent SCT, median PFS is 15 mos and OS has not been reached. Multivariate analysis revealed that the no. of prior drugs and response to the preceding regimen significantly influenced OS and PFS; in addition PFS was significantly influenced by performance status and mos since previous chemotherapy. CONCLUSIONS EPOCH is well tolerated and has a high response rate in relapsed/refractory HL. It should be considered as salvage therapy prior to SCT or for palliation in incurable HL. No significant financial relationships to disclose.