Abstract 2359: Adrenergic regulation of MCP-1 leads to enhanced macrophage recruitment and ovarian carcinoma growth

Increased adrenergic signaling is known to promote tumor progression, but the underlying mechanisms remain poorly understood. Tumor associated macrophages (TAMs) are key components of the tumor microenvironment that contribute to pro-inflammatory processes and tumor growth. Recently, it has been reported that patients with higher levels of adrenergic signaling have higher counts of MMP-9-producing TAMs. Here, we examined factors responsible for stress-mediated effects on monocyte/macrophage recruitment into the tumor microenvironment and the resultant effects on tumor growth. Conditioned media from norepinephrine- or epinephrine-treated ADRB positive SKOV3ip1 ovarian cancer cells had significantly increased levels of pro-inflammatory cytokines, such as MCP1, fractalkine, IL6, IL8 and VEGF. MCP1, a key modulator of monocyte/macrophage recruitment, gene and protein levels were significantly increased in vitro after catecholamine exposure, which was mediated by cAMP and PKA, while this effect was abrogated by a beta-blocker. SKOV3ip1 tumor samples from mice, subjected to daily restraint stress, had elevated MCP1 gene and protein expression levels, increased CD14+ cells, and increased infiltration of CD68+ cells. Both, propranolol, a non-specific beta-blocker, and hMCP1 siRNA packaged in DOPC nanoparticles significantly abrogated daily restraint stress-induced tumor growth and inhibited infiltration of CD68+ and F4/80+ cells. Of patient samples evaluated (n = 462), 28% had elevat...
Source: Cancer Research - Category: Cancer & Oncology Authors: Tags: Tumor Biology Source Type: research