VEGF induces MCL-1 upregulation and protects multiple myeloma cells against apoptosis

Authors:
Le Gouill S, Podar K, Amiot M, Hideshima T, Chauhan D, Itshitsuka K, Kumar S, Raje N, Richardson PG, Harousseau JL and Anderson KC
In:
Source: Blood
Publication Date: (2004)
Issue: 104(9): 2886-2892
Research Area:
Cancer Research/Cell Biology
Cells used in publication:
MM.1S
Species: human
Tissue Origin: blood
Platform:
Nucleofector® I/II/2b
Abstract
Interleukin-6 (IL-6) triggers multiple myeloma (MM) cell proliferation and protects against apoptosis by up-regulating myeloid cell leukemia 1 (Mcl-1). Vascular endothelial growth factor (VEGF) induces modest proliferation of MM cells and induces IL-6 secretion in a paracrine loop involving MM cells and bone marrow stromal cells. Using murine embryonic fibroblast cell lines as a model (Mcl-1(wt/wt) and Mcl-1(Delta/null) MEFs), we here demonstrate that deletion of Mcl-1 reduces fetal bovine serum (FBS)-, VEGF-, and IL-6-induced proliferation. We also show that VEGF up-regulates Mcl-1 expression in a time- and dose-dependent manner in 3 human MM cell lines and MM patient cells. Importantly, we demonstrate that the pan-VEGF inhibitor, GW654652, inhibits VEGF-induced up-regulation of Mcl-1 and, as with Mcl-1 siRNA, is associated with decreased proliferation and induction of apoptosis. Finally, we show that VEGF protects MM patient cells against FBS starvation-induced apoptosis. Our studies therefore demonstrate that VEGF-induced MM cell proliferation and survival are mediated via Mcl-1, providing the preclinical framework for novel therapeutics targeting Mcl-1 and/or VEGF to improve patient outcome in MM.