Lentiviral shRNA silencing of BDNF inhibits in vivo multiple myeloma growth and angiogenesis via down‐regulated stroma‐derived VEGF expression in the bone marrow milieu

Abstract

Bone marrow (BM) neovascularization and vascular endothelial growth factor (VEGF) expression in multiple myeloma (MM) correlate with disease progression. Brain derived neurotrophic factor (BDNF) is highly expressed by malignant plasma cells isolated from the majority of MM patients. Recently, BDNF was identified as a potential proangiogenic factor for the promotion of endothelial cell survival, induction of neoangiogenesis in ischemic tissues, and increase of VEGF expression in neuroblastoma. Since tropomyosin receptor kinase B (TrkB), the receptor of BDNF, is expressed by stromal cells within the BM milieu, here we sought to evaluate the involvement of BDNF/TrkB in myeloma–marrow stroma interaction and its effects on BM angiogenesis. TrkB was abundantly expressed by bone marrow stromal cells (BMSCs) isolated from healthy donors. Stimulation of BMSCs with BDNF induced a time‐ and dose‐ dependent increase in VEGF secretion, which was completely abolished by K252α, an inhibitor of TrkB. BDNF triggered activation of signal transducer and activator of transcription 3 (STAT3) and activator protein‐1 (AP‐1), whereas STAT3 was involved in mediating VEGF expression. We further delineated the biological significance of BDNF in MM by using lentiviral short‐interfering RNA (shRNA). When myeloma cells were cocultured with BMSCs in a noncontact Transwell system, VEGF levels in supernatants were significantly decreased when BDNF expression was knocked down. Furthermore, silencing of BDNF expression significantly inhibited xenograft tumor growth and angiogenesis, and prolonged survival in mouse model. Our studies demonstrate that BDNF, as a potential stimulator of angiogenesis, contributes to MM tumorgenesis; it mediates stromal–MM cell interactions via selective activation of specific receptor TrkB and downstream signal transducer STAT3, regulating VEGF secretion. (Cancer Sci 2010; 101: 1117–1124)

Inhibition of BDNF in Multiple Myeloma Blocks Osteoclastogenesis via Down-Regulated Stroma-Derived RANKL Expression Both In Vitro and In Vivo

“…Basal levels of BDNF and RANKL in these marrow plasma were measured using Human BDNF Quantikine ELISA kit and Human RANKL Quantikine ELISA kit from R&D Systems (Minneapolis, MN). Human primary BMSCs and pre-osteoclasts were prepared and identified as previously described [22], [26]. Then a series of co- and triple- culture systems (MM-BMSCs, BMSCs-preOCs, MM-BMSCs-preOCs) were implemented and treated with various conditions.…”

Brain-Derived Neurotrophic Factor Knockdown Blocks the Angiogenic and Protective Effects of Angiotensin Modulation After Experimental Stroke

“…[8,9] In addition, VEGF expression has been shown to be regulated by BDNF. [31,32] It is still unknown whether BDNF regulates VEGF expression in the brain after stroke. Astrocytes and neurons are major sources of VEGF after stroke.…”

“…[51] In cancer tissues, VEGF expression was found to be regulated by BDNF. [32,31] Additionally, the expression of both proteins was demonstrated to be co-regulated. [47] Our data shows increase in VEGF expression with candesartan in NTC treated animals as compared to those treated with candesartan after BDNF knockdown.…”

Molecular and cellular mechanisms underlying the role of blood vessels in spinal cord injury and repair

“…2a), an event that is regulated by platelet-derived growth factor (PDGF-BB) produced by the "migrating" tip cells (Hellstrom et al 1999;Huang et al 2010). VEGF-C is an essential paracrine regulator of PDGF-BB expression; blockage of the VEGF type 3 receptor by using antibody AFL-4 prevents FGF-2 (fibroblast growth factor-2)-mediated blood flow recovery and causes capillary dilation in ischemic limbs (Onimaru et al 2009).…”

“…EPO might affect vascular remodeling by inducing VEGF secretion from neural progenitor cells and/or up regulating VEGF receptor 2 expression in endothelial cells (Wang et al 2008). EPO treatment has also been found to increase brain-derived neurotropic factor (BDNF) expression (Mahmood et al 2007), which could, through VEGF, promote angiogenesis (Zhang et al 2010).…”