Fibroblasts in Nodular Sclerosing Classical Hodgkin Lymphoma Are Defined by a Specific Phenotype and Protect Tumor Cells from Brentuximab-Vedotin Induced Injury.

Martin-Leo Hansmann,Claudia Döring,Maciej Giefing,Ralf Küppers,Katrin Bankov,Chiara Cencioni,Sylvia Hartmann,Adam Ustaszewski,Carlo Gaetano,Marco Herling,Francesco Spallotta

doi:10.3390/cancers11111687

Abstract

Classical Hodgkin lymphoma (cHL) is one of the most common malignant lymphomas in Western Europe. The nodular sclerosing subtype of cHL (NS cHL) is characterized by a proliferation of fibroblasts in the tumor microenvironment, leading to fibrotic bands surrounding the lymphoma infiltrate. Several studies have described a crosstalk between the tumour cells of cHL, the Hodgkin- and Reed-Sternberg (HRS) cells, and cancer-associated fibroblasts. However, to date a deep molecular characterization of these fibroblasts is lacking. Thus, the aim of the present study is a comprehensive characterization of these fibroblasts. Gene expression profiling and methylation profiles of fibroblasts isolated from primary lymph node suspensions revealed persistent differences between fibroblasts obtained from NS cHL and lymphadenitis. NS cHL derived fibroblasts exhibit a myofibroblastic phenotype characterized by myocardin (MYOCD) expression. Moreover, TIMP3, an inhibitor of matrix metalloproteinases, was strongly upregulated in NS cHL fibroblasts, likely contributing to the accumulation of collagen in sclerotic bands of NS cHL. As previously shown for other types of cancer-associated fibroblasts, treatment by luteolin could reverse this fibroblast phenotype and decrease TIMP3 secretion. NS cHL fibroblasts showed enhanced proliferation when they were exposed to soluble factors released from HRS cells. For HRS cells, soluble factors from fibroblasts were not sufficient to protect them from Brentuximab-Vedotin induced cell death. However, HRS cells adherent to fibroblasts were protected from Brentuximab-Vedotin induced injury. In summary, we confirm the importance of fibroblasts for HRS cell survival and identify TIMP3 which probably contributes as a major factor to the typical fibrosis observed in NS cHL.

Highlights

Classical Hodgkin lymphoma is one of the most frequent malignant lymphomas
Fibroblasts were isolated from cell suspensions of Classical Hodgkin lymphoma (cHL) and lymphadenitis lymph node biopsy specimens
We identified MYOCD and tissue inhibitor of metalloproteinase 3 (TIMP3) as generally deregulated genes in cHL fibroblasts

Summary

Introduction

Classical Hodgkin lymphoma (cHL) is one of the most frequent malignant lymphomas. Unlike in most other types of B cell lymphoma, the tumor cells in HL, the Hodgkin-Reed-Sternberg (HRS) cells only represent a minority in the infiltrate, frequently around 1% [1]. In Western Europe, the nodular sclerosing (NS cHL) subtype is most frequently encountered This subtype mainly affects adolescents, occurs frequently in mediastinal localization and is usually not Epstein–Barr virus-associated [2]. In this subtype, a proliferation of fibroblasts is observed, leading to sclerosing bands that confine nodular compartments [3]. Malignant cells recruit and re-educate their surrounding cells to establish a tumor-supportive milieu This affects the biology and function of FRCs. Once reprogrammed to cancer-associated fibroblasts (CAFs), they can induce remodeling of the extracellular matrix (ECM) [5]. The induction of ABC-transporters was shown in vitro for CAFs isolated from lymph nodes affected by follicular lymphoma and diffuse large B cell lymphoma [9]

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