Lymphoma cell adhesion-induced expression of B cell-activating factor of the TNF family in bone marrow stromal cells protects non-Hodgkin's B lymphoma cells from apoptosis

Abstract

This study explores whether lymphoma cell adhesion-induced B cell-activating factor (BAFF) expression in bone marrow stromal cells (BMSCs) protects B lymphoma cells from apoptosis. We first showed protection of lymphoma cells from apoptosis by conditioned medium of a stromal cell-lymphoma cell coculture, either spontaneous or induced by mitoxantrone, implying a role for soluble factor(s) in lymphoma cell survival.

A microenvironment-mediated c-Myc/miR-548m/HDAC6 amplification loop in non-Hodgkin B cell lymphomas

“…Presence of DC gene expression signature in lymphoma indicates prognosis (26). Our and other studies have shown that cell adhesion to stroma cells (HK and HS-5 cells) confers a multidrug-resistant phenotype and that disruption of cell adhesion-mediated signaling may increase the efficacy of cytotoxic agents (2,(27)(28)(29)(30). To this end, our laboratory has focused on identifying targets that contribute to stroma-mediated drug resistance and tumor progression.…”

“…Tubastatin A was purchased from BioVision Incorporated, and mitoxantrone was purchased from Sigma-Aldrich. At the indicated times, cells were collected and washed, and Western blot and apoptosis analyses were then performed as previously described (28,46). JQ1 was provided by James E. Bradner (Dana-Farber Cancer Institute, Boston, Massachusetts, USA), and DZNep was provided by Victor E. Marquez (National Cancer Institute, NIH, Frederick, Maryland, USA).…”

“…The human lymphoma cell lines Jeko-1, HBL-2, SUDHL-4, and SUDHL-10 were provided and maintained as previously described (28). SUDHL-4 and SUDHL-10 are germinal center-type large B cell lymphoma cell lines, and Jeko-1 and HBL-2 are MCL cell lines.…”

“…Diffuse large B cell lymphoma and MCL cells were obtained from fresh biopsy-derived lymphoma tissues (lymph nodes) after informed consent from patients. The primary lymphoma cells and CD19-positive cells were isolated by using CD19 microbeads with the AutoMACS Magnetic Cell Sorter according to the manufacturer's instructions (Miltenyi Biotec), as described previously (28). Either lymphoma cell lines or CD19-sorted lymphoma cells (from diffuse large cell lymphomas, 1.5 × 10 6 cells/ml) were adhered to a preestablished monolayer of HK cells or kept in suspension for 12 to 24 hours.…”

“…HDAC6 small hairpin RNAs (pSM2 shRNA vector) and control shRNAs (pSM2 nonsilencing) were obtained from Cold Spring Harbor Laboratory. For transient expression, cell lines were transfected by electroporation using Nucleofector according to the manufacturer's instructions and as described previously (28). For additional shRNA knockdown experiments, Jeko-1 or SUDHL-4 cells were transfected with 0.5 μg psiHIV-U6 of OmicsLink shHDAC6 RNA Expression Clones: shHDAC6.GC1, shHDAC6.GC2, shHDAC6.GC3, shHDAC6.GC4, and sh-scrambled control (GeneCopoeia).…”