Bendamustine increases interleukin-10 secretion from B cells via p38 MAP kinase activation

Area of Science:

• Immunology
• Pharmacology
• Cell Biology

Background:

• Bendamustine is an alkylating agent used in cancer therapy.
• Its effects on B cell function beyond cytotoxicity are not fully understood.
• Interleukin-10 (IL-10) is a key anti-inflammatory cytokine with therapeutic potential in autoimmune diseases.

Purpose of the Study:

• To investigate the impact of bendamustine on B cell functions, specifically proliferation, IgM secretion, and IL-10 production.
• To elucidate the molecular mechanisms underlying bendamustine-induced IL-10 production.
• To explore the potential of bendamustine as a therapeutic agent for autoimmune diseases.

Main Methods:

• In vitro studies using Ramos cells (human B cell line) and peripheral blood mononuclear cells (PBMC) from healthy donors.
• Bendamustine treatment at varying concentrations (25-100μM).
• Assessment of cell proliferation, IgM secretion, IL-10 production, and p38 MAP kinase phosphorylation.
• Identification of Sp1 as a downstream transcription factor using molecular inhibitors and DNA binding assays.
• Stimulation of PBMC with anti-IgM, anti-CD40, recombinant human IL-21 (rhIL-21), and recombinant human soluble BAFF (rhsBAFF).

Main Results:

• Bendamustine significantly inhibited Ramos cell proliferation and IgM secretion in a dose-dependent manner.
• Bendamustine dramatically increased IL-10 production (>10-fold) by B cells at growth-inhibitory concentrations.
• The p38 MAP kinase-Sp1 pathway was identified as crucial for bendamustine-induced IL-10 production.
• Bendamustine enhanced IL-10 production in B cells from healthy donors under various stimulatory conditions.

Conclusions:

• Bendamustine exhibits immunomodulatory effects on B cells, inhibiting proliferation while potently inducing IL-10.
• The p38 MAP kinase and Sp1 signaling pathway mediates bendamustine-induced IL-10 production.
• Upregulation of IL-10 by bendamustine presents a novel therapeutic strategy for inflammatory and autoimmune diseases.