Pathologic Correlates of Primary Central Nervous System Lymphoma Defined in an Orthotopic Xenograft Model
15 Mar 2009-Clinical Cancer Research (American Association for Cancer Research)-Vol. 15, Iss: 6, pp 1989-1997
TL;DR: Intracerebral implantation of Raji cells results in a reproducible and invasive xenograft model, which recapitulates the histopathology and molecular features of PCNSL, and is suitable for preclinical testing of novel agents.
Abstract: Purpose: The prospect for advances in the treatment of patients with primary central nervous system lymphoma (PCNSL) is likely dependent on the systematic evaluation of its pathobiology. Animal models of PCNSL are needed to facilitate the analysis of its molecular pathogenesis and for the efficient evaluation of novel therapeutics. Experimental Design: We characterized the molecular pathology of CNS lymphoma tumors generated by the intracerebral implantation of Raji B lymphoma cells in athymic mice. Lymphoma cells were modified for bioluminescence imaging to facilitate monitoring of tumor growth and response to therapy. In parallel, we identified molecular features of lymphoma xenograft histopathology that are evident in human PCNSL specimens. Results: Intracerebral Raji tumors were determined to faithfully reflect the molecular pathogenesis of PCNSL, including the predominant immunophenotypic state of differentiation of lymphoma cells and their reactive microenvironment. We show the expression of interleukin-4 by Raji and other B lymphoma cell lines in vitro and by Raji tumors in vivo and provide evidence for a role of this cytokine in the M2 polarization of lymphoma macrophages both in the murine model and in diagnostic specimens of human PCNSL. Conclusion: Intracerebral implantation of Raji cells results in a reproducible and invasive xenograft model, which recapitulates the histopathology and molecular features of PCNSL, and is suitable for preclinical testing of novel agents. We also show for the first time the feasibility and accuracy of tumor bioluminescence in the monitoring of a highly infiltrative brain tumor.
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TL;DR: Progress in in vitro screening platforms as well as orthotopic and 'orthometastatic' xenograft mouse models has enabled comprehensive characterization of the impact of the tumour microenvironment on therapeutic efficacy, which can hopefully bridge the gap between preclinical studies and clinical trials of anticancer agents.
Abstract: The role of stromal cells and the tumour microenvironment in general in modulating tumour sensitivity is increasingly becoming a key consideration for the development of active anticancer therapeutics. Here, we discuss how these tumour-stromal interactions affect tumour cell signalling, survival, proliferation and drug sensitivity. Particular emphasis is placed on the ability of stromal cells to confer - to tumour cells - resistance or sensitization to different classes of therapeutics, depending on the specific microenvironmental context. The mechanistic understanding of these microenvironmental interactions can influence the evaluation and selection of candidate agents for various cancers, in both the primary site as well as the metastatic setting. Progress in in vitro screening platforms as well as orthotopic and 'orthometastatic' xenograft mouse models has enabled comprehensive characterization of the impact of the tumour microenvironment on therapeutic efficacy. These recent advances can hopefully bridge the gap between preclinical studies and clinical trials of anticancer agents.
395 citations
TL;DR: This review will focus on PCNSL in the immunocompetent host, an uncommon variant of extranodal non-Hodgkin lymphoma that has been challenging to study and an effective standard of care has been difficult to establish.
Abstract: Primary central nervous system (CNS) lymphoma (PCNSL), an uncommon variant of extranodal non-Hodgkin lymphoma (NHL), can affect any part of the neuraxis including the eyes, brain, leptomeninges, or spinal cord. It accounts for approximately 3% of all the primary CNS tumors diagnosed each year in the United States. Congenital or acquired immunodeficiency is the only established risk factor for PCNSL, and individuals with human immunodeficiency virus (HIV) infection are at greater risk for developing this tumor. Infection with HIV likely accounted for the increased incidence in PCNSL observed from 1970 to 2000, but over the last decade the number of cases of PCNSL has stabilized or decreased to about 0.47 cases per 100 000 persons. Owing to the rarity of PCNSL, the disease has been challenging to study and an effective standard of care has been difficult to establish. Unfortunately, although durable remissions may be achieved for some patients with PCNSL, the tumor relapses in most cases. In this review, we will focus on PCNSL in the immunocompetent host.
180 citations
Cites background from "Pathologic Correlates of Primary Ce..."
...Recently, the first mouse model of PCNSL was developed; it could potentially be used to test new therapeutic agents that target these molecular abnormalities including the IL-4 signaling pathway.(4)...
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TL;DR: It is demonstrated for the first time that elevated CXCL13 concentration in cerebrospinal fluid (CSF) is prognostic and that CXC chemokine ligand and IL-10 mediate chemotaxis of lymphoma cells isolated from CNS lymphoma lesions.
178 citations
Cites methods from "Pathologic Correlates of Primary Ce..."
...To enable the generation of adequate numbers of cells for in vitro assays, patient-derived lymphoma cells were implanted into the cerebrum of NOD-SCID g mice whereupon they expanded to form visible tumors within 4 weeks, according to an Institutional Animal Care and Use Committee–approved protocol.(17) At necropsy, intracranial lymphoma xenografts were isolated, and malignant B cells purified by CD191 selection by MACS (Miltenyi Biotech) for in vitro migration assays....
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TL;DR: POM is a promising therapeutic agent for CNS lymphoma with excellent CNS penetration, significant preclinical therapeutic activity, and a major impact on the tumor microenvironment.
Abstract: Primary CNS lymphoma carries a poor prognosis. Novel therapeutic agents are urgently needed. Pomalidomide (POM) is a novel immunomodulatory drug with anti-lymphoma activity. CNS pharmacokinetic analysis was performed in rats to assess the CNS penetration of POM. Preclinical evaluation of POM was performed in two murine models to assess its therapeutic activity against CNS lymphoma. The impact of POM on the CNS lymphoma immune microenvironment was evaluated by immunohistochemistry and immunofluorescence. In vitro cell culture experiments were carried out to further investigate the impact of POM on the biology of macrophages. POM crosses the blood brain barrier with CNS penetration of ~ 39%. Preclinical evaluations showed that it had significant therapeutic activity against CNS lymphoma with significant reduction in tumor growth rate and prolongation of survival, that it had a major impact on the tumor microenvironment with an increase in macrophages and natural killer cells, and that it decreased M2-polarized tumor-associated macrophages and increased M1-polarized macrophages when macrophages were evaluated based on polarization status. In vitro studies using various macrophage models showed that POM converted the polarization status of IL4-stimulated macrophages from M2 to M1, that M2 to M1 conversion by POM in the polarization status of lymphoma-associated macrophages is dependent on the presence of NK cells, that POM induced M2 to M1 conversion in the polarization of macrophages by inactivating STAT6 signaling and activating STAT1 signaling, and that POM functionally increased the phagocytic activity of macrophages. Based on our findings, POM is a promising therapeutic agent for CNS lymphoma with excellent CNS penetration, significant preclinical therapeutic activity, and a major impact on the tumor microenvironment. It can induce significant biological changes in tumor-associated macrophages, which likely play a major role in its therapeutic activity against CNS lymphoma. POM should be further evaluated in clinical trials.
74 citations
Cites background from "Pathologic Correlates of Primary Ce..."
...When they were treated with IL4 followed by POM, they expressed pSTAT1 and iNOS, and did not express pSTAT6 and YM1/FXIIIA, indicating conversion of their polarization from M2 to M1 via activation of STAT1 signalling and inactivation of STAT6 signalling....
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...These cells expressed pSTAT6 and YM1/FXIIIA [12] on treatment with IL4 followed by DMSO, indicating M2 polarization via IL4/STAT6 signalling pathway....
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...In experiments in which IL-4 was used to induce M2 polarization of macrophages, cells were treated with IL-4 (20ng/ml) for 48 hours followed by treatment with POM (10ug/ml) or DMSO control for 48 hours....
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...It has been shown that macrophages in PCNSL are M2 polarized related to upregulation of IL4 in CNS lymphoma [12,13]....
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...POM converted the IL-4-induced M2 polarization of macrophages as indicated by FXIII A and pSTAT6 expression to M1 polarization as indicated by iNOS and pSTAT1 expression....
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TL;DR: The cell lines and murine models used to study lymphomagenesis, the lymphoma microenvironment, and the efficacy of new therapies are summarized to improve understanding of the molecular and cellular mechanisms of tumor genesis and development as well as the fundamental processes governing the interaction of tumors and their host tissues.
Abstract: Human B-cell lymphomas, the fourth most common hematologic malignancy, are currently the subject of extensive research. The limited accessibility of biopsies, the heterogeneity among patients, and the subtypes of lymphomas have necessitated the development of animal models to decipher immune escape mechanisms and design new therapies. Here, we summarize the cell lines and murine models used to study lymphomagenesis, the lymphoma microenvironment, and the efficacy of new therapies. These data allow us to understand the role of the immune system in the fight against tumors. Exploring the advantages and limitations of immunocompetent versus immunodeficient models improves our understanding of the molecular and cellular mechanisms of tumor genesis and development as well as the fundamental processes governing the interaction of tumors and their host tissues. We posit that these basic preclinical investigations will open up new and promising approaches to designing better therapies.
68 citations
References
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TL;DR: Ym1 is established as a highly inducible STAT6-dependent transcript in TH2-biased inflammation and Cis-active elements in the Ym1 promoter that are required for this transcriptional response are defined.
232 citations
01 Jan 2008
TL;DR: Results show that MC can predict outcome of FL patients and that rituximab is able to circumvent the unfavorable outcome associated with high MC.
Abstract: Purpose High amounts of intratumoral macrophages have been shown to correlate with poor prognosis in patients with follicular lymphoma (FL) treated with chemotherapy without rituximab. We tried to establish whether intratumoral macrophage count ( MC) definitely is able to predict the outcome of FL patients in the rituximab era. Patients and Methods We analyzed immunohistochemical CD68 expression in 194 FL patients from the FL-2000 trial, randomly assigned to receive cyclophosphamide, doxorubicin, etoposide, prednisolone, and interferon (CHVP-I) or rituximab plus CHVP-I. Immunohistochemistry was performed on paraffin sections using anti-CD68 KP1 antibody, and stained macrophages were scored on high-power field (hpf) in either intrafollicular ( IF) or extrafollicular (EF) areas. Results For IF MC, the best cutoff point was estimated at 10 macrophages/ hpf. Low IF MC was significantly associated with a better event-free survival (EFS; P =.011). However, this effect was observed only in the CHVP-I arm ( P =.012) and not in the rituximab plus CHVP-I arm. Using a cutoff of 15 IF MC, we found no significant association with EFS. For EF MC, fewer than 22 macrophages/ hpf were associated with better EFS in the CHVP-I arm ( P =.02) but not in the rituximab plus CHVP-I arm. Conclusion These results show that MC can predict outcome of FL patients and that rituximab is able to circumvent the unfavorable outcome associated with high MC.
219 citations
TL;DR: This is the first description of a biological mechanism and functional significance of PNI, and three of 15 genes up-regulated in the cDNA microarray were involved in the apoptosis signaling pathway (NFκB), and its downstream targets defender against cell death 1 and PIM-2.
Abstract: Perineural invasion (PNI) is the major mechanism of prostate cancer spread outside the prostate. Apoptotic and proliferation indices were determined in PNI cells using the PNI in vitro model and human PNI in tissue microarrays. RNA was extracted from the PNI model and controls and evaluated by cDNA microarray analysis. Differential expression of candidate genes was confirmed by real-time quantitative PCR, fluorescence, and immunohistochemistry using tissue microarrays. Genistein and BAY 11-7085 were added to the supernatant of cocultures and controls in microchamber cultures. The significance of nuclear factor B (NFB) nuclear translocation in human PNI was analyzed using Kaplan-Meier analysis. An increase in proliferation and a decrease in apoptosis were observed in human PNI cells and the PNI model as compared with controls. Three of 15 genes up-regulated in the cDNA microarray were involved in the apoptosis signaling pathway (NFB), and its downstream targets defender against cell death 1 and PIM-2. The increase was corroborated by real-time quantitative PCR and immunofluorescence. NFB nuclear translocation was seen in the in vitro model and human tissues, where strong nuclear expression was associated with a decrease in recurrence-free survival. Addition of genistein and BAY 11-7085 resulted in a decrease in NFB, PIM-2 and defender against cell death 1 as well as a reversal of the inhibition of apoptosis. This is the first description of a biological mechanism and functional significance of PNI. Cancer cells in a perineural location acquire a survival and growth advantage using a NFB survival pathway. Targeting PNI might help detain local spread of the tumor and influence survival.
207 citations
TL;DR: This combination of rituximab and temozolomide provides a reasonable therapeutic alternative for older patients with progressive PCNSL and merits further study.
Abstract: The authors evaluated the efficacy of a combination of rituximab and temozolomide for recurrent or refractory primary CNS lymphoma (PCNSL). Fifteen patients with a median age of 69 years had a 53% objective response rate with acceptable toxicity. Median overall survival is 14 months and median progression free survival of responding patients is 7.7 months. This combination merits further study and provides a reasonable therapeutic alternative for older patients with progressive PCNSL.
196 citations
TL;DR: It is demonstrated that interleukin-4 (IL-4) is expressed by tumor vasculature as well as by tumor cells in CNS lymphomas, and high expression of activated STAT6 in tumors was associated with short survival in an independent set of patients with primary CNS lymphoma who were treated with high-dose intravenous methotrexate therapy.
195 citations
"Pathologic Correlates of Primary Ce..." refers background in this paper
...and a candidate mediator of CNS lymphoma invasiveness (7)....
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...significant role for IL-4 signal transduction in CNS lymphoma pathogenesis (7)....
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...PCNSL diagnostic specimens, the results of which showed that IL-4 RNA was reproducibly expressed by lymphoma cells in PCNSL (7) as well as in cases of nodal large B-cell lymphoma....
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...In addition to Bcl-6 and MUM-1, gene expression analyses have revealed ectopic expression of interleukin-4 (IL-4), a B-cell growth factor, by tumor cells and endothelia in PCNSL specimens (7)....
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