Antiangiogenic therapies in non-Hodgkin's lymphoma

Procarbazine, prednisolone and cyclophosphamide (PPC) oral combination chemotherapy protocol for canine lymphoma

Orally administered daily chemotherapy offers a novel treatment approach for canine lymphoma in a population of dogs that have failed or not tolerated maximum tolerable dose chemotherapy. A multidrug oral chemotherapy protocol was designed and implemented for the treatment of fifty dogs with multicentric lymphoma with minimal side effects. The protocol consisted of oral procarbazine, prednisolone and cyclophosphamide (PPC) administered daily. Efficacy and toxicity were evaluated by clinical and laboratory evaluation. An overall response rate of 70% was achieved, with 24% and 46% of dogs having a partial and complete response, respectively, to treatment with the PPC protocol. Response to the PPC protocol (complete or partial) and age were the only factors identified as prognostic for time from initiation of the PPC chemotherapy until death. Overall, the protocol was very well tolerated with only one dog requiring protocol discontinuation due to grade 4 thrombocytopenia. Eight dogs recorded gastrointestinal toxicities, seven grade I and one grade II toxicity. These findings demonstrate that the administration of a continuous oral combination chemotherapy can provide comparable survival times in the rescue setting in dogs with multicentric lymphoma with minimal side effects.

Angiogenesis in Lymph Nodes Is a Critical Regulator of Immune Response and Lymphoma Growth

Tumor-induced remodeling of the microenvironment in lymph nodes (LNs) includes the formation of blood vessels, which goes beyond the regulation of metabolism, and shaping a survival niche for tumor cells. In contrast to solid tumors, which primarily rely on neo-angiogenesis, hematopoietic malignancies usually grow within pre-vascularized autochthonous niches in secondary lymphatic organs or the bone marrow. The mechanisms of vascular remodeling in expanding LNs during infection-induced responses have been studied in more detail; in contrast, insights into the conditions of lymphoma growth and lodging remain enigmatic. Based on previous murine studies and clinical trials in human, we conclude that there is not a universal LN-specific angiogenic program applicable. Instead, signaling pathways that are tightly connected to autochthonous and infiltrating cell types contribute variably to LN vascular expansion. Inflammation related angiogenesis within LNs relies on dendritic cell derived pro-inflammatory cytokines stimulating vascular endothelial growth factor-A (VEGF-A) expression in fibroblastic reticular cells, which in turn triggers vessel growth. In high-grade B cell lymphoma, angiogenesis correlates with poor prognosis. Lymphoma cells immigrate and grow in LNs and provide pro-angiogenic growth factors themselves. In contrast to infectious stimuli that impact on LN vasculature, they do not trigger the typical inflammatory and hypoxia-related stroma-remodeling cascade. Blood vessels in LNs are unique in selective recruitment of lymphocytes via high endothelial venules (HEVs). The dissemination routes of neoplastic lymphocytes are usually disease stage dependent. Early seeding via the blood stream requires the expression of the homeostatic chemokine receptor CCR7 and of L-selectin, both cooperate to facilitate transmigration of tumor and also of protective tumor-reactive lymphocytes via HEV structures. In this view, the HEV route is not only relevant for lymphoma cell homing, but also for a continuous immunosurveillance. We envision that HEV functional and structural alterations during lymphomagenesis are not only key to vascular remodeling, but also impact on tumor cell accessibility when targeted by T cell-mediated immunotherapies.

Ki67 and CD31 Differential Expression in Cutaneous T-Cell Lymphoma and Its Mimickers: Association with Clinicopathological Criteria and Disease Advancement

Background

Cell proliferation and angiogenesis are important in progression of cancerous processes. Differentiating cutaneous T-cell lymphoma (CTCL) from its mimicking dermatoses and prognosticating it are challenging.

Aim

This study assesses cell proliferation and angiogenesis in different CTCL subtypes using immunohistochemistry (IHC) for Ki67 and CD31 to testify their usability in differentiating CTCL from mimicking dermatoses and discriminating CTCL subtypes from each other with correlation to clinicopathological parameters and disease advancement.

Patients and Methods

IHC for Ki67 and CD31 were applied to skin biopsies from 81 patients divided into CTCL (n=59) and dermatoses (n=22) groups. Hot-spot analysis was used to score Ki67 and CD31 microvascular density (MVD) semiquantitatively. Statistical analysis was performed to compare Ki67 index and MVD between CTCL and dermatoses. CTCL subgroups were compared to each other. Ki67 index and CD31 were compared to age, gender, skin and nodal involvement, blood tumor burden and TNMB stage.

Results and Conclusion

There were significant differences in proliferation index and MVD between dermatoses and CTCL, and between dermatoses and all CTCL subtypes with exception of Ki67 in early mycosis fungoides (MF) and CD31 in patch lesions. Increased cell proliferation and MVD were significantly associated with older age, T3 and 4 skin involvement, significant nodes (N1-3), positive blood tumor burden (B1,2) in CTCL and TNMB stage of MF. Both markers differentiated significantly late from early MF, classic MF from its variants and non-MF CTCL from total MF, but not from late MF. In conclusion, Ki67 and CD31 expression in skin biopsies using IHC reproduces the role of proliferation and angiogenesis in the differential diagnosis and prognostication of CTCL being expressed at higher levels in aggressive than indolent CTCL. Therapeutic targeting of cell proliferation and angiogenesis may improve patient’s outcome in CTCL. Usability of these markers into patient’s stratification should be considered in further studies.

Microenvironment Cell Contribution to Lymphoma Immunity

Lymphoma microenvironment is a complex system composed of stromal cells, blood vessels, immune cells as well as extracellular matrix, cytokines, exosomes, and chemokines. In this review, we describe the function, localization, and interactions between various cellular components. We also summarize their contribution to lymphoma immunity in the era of immunotherapy. Publications were identified from searching Pubmed. Primary literature was carefully evaluated for replicability before incorporating into the review. We describe the roles of mesenchymal stem/stromal cells (MSCs), lymphoma-associated macrophages (LAMs), dendritic cells, cytotoxic T cells, PD-1 expressing CD4+ tumor infiltrating lymphocytes (TILs), T-cells expressing markers of exhaustion such as TIM-3 and LAG-3, regulatory T cells, and natural killer cells. While it is not in itself a cell, we also include a brief overview of the lymphoma exosome and how it contributes to anti-tumor effect as well as immune dysfunction. Understanding the cellular players that comprise the lymphoma microenvironment is critical to developing novel therapeutics that can help block the signals for immune escape and promote tumor surveillance. It may also be the key to understanding mechanisms of resistance to immune checkpoint blockade and immune-related adverse events due to certain types of immunotherapy.

Risk factors for the evaluation of potential central nervous system metastasis in Burkitt's lymphoma: a case study and literature review

Burkitt's lymphoma (BL) is a malignancy of B lymphocytes. The rapid growth rate and frequent systemic spread result in most patients presenting with advanced disease at diagnosis. Cerebrospinal fluid cytology is the gold standard (with very high accuracy) for diagnosing BL central nervous system (CNS) metastasis; however, the low sensitivity of this method limits its clinical applications. Here, we report a case of BL with CNS metastasis. The levels of vascular endothelial growth factor (VEGF)-A and VEGF-C in the serum and cerebrospinal fluid were used to evaluate the status of BL remission and recurrence. Comparisons were made between VEGF and the other risk factors used in evaluating CNS metastasis. Although not in strict accordance, VEGF levels mirrored the disease course. Therefore, VEGF may reflect the status of BL CNS metastasis. Understanding the role of VEGF in CNS metastasis may help to improve the staging and risk classification of BL as well as the investigation of targeted therapy.

Autophagy in blood cancers: biological role and therapeutic implications

Autophagy is a cell recycling process the molecular apparatus of which has been identified over the past decade. Autophagy allows cells to survive starvation and inhospitable conditions and plays a key role in numerous physiological functions, including hematopoiesis and immune responses. In hematologic malignancies, autophagy can either act as a chemo-resistance mechanism or have tumor suppressive functions, depending on the context. In addition, autophagy is involved in other important aspects of blood cancers as it promotes immune competence and anti-cancer immunity, and may even help enhance patient tolerance to standard treatments. Approaches exploiting autophagy, either to activate or inhibit it, could find broad application in hematologic malignancies and contribute to improved clinical outcomes. These aspects are discussed here together with a brief introduction to the molecular machinery of autophagy and to its role in blood cell physiology.

Paradoxical regulation of hypoxia inducible factor-1α (HIF-1α) by histone deacetylase inhibitor in diffuse large B-cell lymphoma

Hypoxia inducible factor (HIF) is important in cancer, as it regulates various oncogenic genes as well as genes involved in cell survival, proliferation, and migration. Elevated HIF-1 protein promotes a more aggressive tumor phenotype, and greater HIF-1 expression has been demonstrated to correlate with poorer prognosis, increased risk of metastasis and increased mortality. Recent reports suggest that HIF-1 activates autophagy, a lysosomal degradation pathway which may promote tumor cell survival. We show here that HIF-1α expression is constitutively active in multiple diffuse large B cell lymphoma (DLBCL) cell lines under normoxia and it is regulated by the PI3K/AKT pathway. PCI-24781, a pan histone deacetylase inhibitor (HDACI), enhanced accumulation of HIF-1α and induced autophagy initially, while extended incubation with the drug resulted in inhibition of HIF-1α. We tested the hypothesis that PCI-24781- induced autophagy is mediated by HIF-1α and that inhibition of HIF-1α in these cells results in attenuation of autophagy and decreased survival. We also provide evidence that autophagy serves as a survival pathway in DLBCL cells treated with PCI-24781 which suggests that the use of autophagy inhibitors such as chloroquine or 3-methyl adenine in combination with PCI-24781 may enhance apoptosis in lymphoma cells.

Antitumor effects of Endostar on non-Hodgkin's lymphoma by regulating endothelial progenitor cells through protein kinase B-dependent pathway

Endothelial progenitor cells (EPCs) play an important role in non-Hodgkin's lymphoma (NHL) development. Endostar is an anti-angiogenic drug designed to stop cancer by nullifying a tumor's ability to obtain oxygen and nutrients. In this study, we examined the anti-angiogenic activities of Endostar on NHL cell lines and murine xenograft model of NHL in vitro and in vivo, respectively, and explored the underlying antiangiogenic mechanism of Endostar. Results showed that Endostar may inhibit the EPC proliferation by reducing the expression of p-protein kinase B, but not p-ERK expression. Our finding could lead to a better understanding of the effects of Endostar on NHL.

Prognostic significance of hypoxia inducible factor-1α and vascular endothelial growth factor expression in patients with diffuse large B-cell lymphoma treated with rituximab

We evaluated hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) expression and their prognostic significance in diffuse large B-cell lymphoma (DLBCL). Expression of HIF-1α and VEGF was studied in 78 patients and results correlated with clinicopathological and prognostic data. HIF-1α and VEGF were expressed in 67% and 84% of patients, respectively, and a significant correlation was demonstrated between them (p < 0.001). Outcome was analyzed according to treatment. HIF-1α positive patients given rituximab demonstrated improved outcome, with 5-year overall survival of 72% for those receiving rituximab versus 65% for those not receiving rituximab, and 5-year progression-free survival (PFS) 76% versus 57%. No correlation was demonstrated between HIF-1α and other prognostic biomarkers including BCL6, CD10 and MUM-1. We demonstrated significantly improved PFS (p = 0.003) in patients receiving rituximab and showing BCL6 overexpression. The results confirm the significant association between HIF-1α and VEGF expression and suggest that HIF-1α expression is a favorable prognostic factor in patients with DLBCL treated with rituximab.

Metronomic therapy for refractory/relapsed lymphoma: the PEP-C low-dose oral combination chemotherapy regimen

BACKGROUND

Metronomic therapy is the application of continuous, low dose chemotherapy. The doses of chemotherapy are usually not sufficient to destroy neoplastic cells, but impact the milieu, particularly angiogenesis.

OBJECTIVE

To determine if the oral PEP-C regimen, consisting of prednisone 20 mgm, etoposide 50 mgm, procarbazine 50 mgm, and cyclophosphamide 50 mgm given in either a daily, alternate day, or fractionated basis, is effective in a variety of lymphomas.

METHODS

One hundred twenty two patients were studied although the majority had low grade or mantle cell lymphoma. All had received at least two or more prior therapies.

RESULTS

Overall, 75% achieved an objective response (OR) with 38% complete responses (CRs) or CRs unconfirmed, and 37% partial responses. ORs were achieved in mantle cell (85%), follicular (88%), marginal zone (71%), and small lymphocytic (67%) lymphomas. Chemosensitive disease was more responsive. Toxicity was minimal.

CONCLUSION

The PEP-C regimen is an easily administered highly effective treatment for heavily pretreated mantle cell and low grade lymphomas.