Abstract PS17-54: Hepatocyte growth factor regulates the expression of chemokine family in vascular endothelial cells; potential implications in clinical breast cancer

Abstract

Abstract Background. Hepatocyte growth factor (HGF) is a powerful cellular migration stimulating cytokine (a motogen) of both epithelial and endothelial cells. The induced cell motility is mainly in the form of chemokinesis, namely undirectional movement of the cells in response to exogenous stimuli. HGF is a key angiogenic and lymphangiogenic factor, partially through its effects on endothelial cellular migration, adhesiveness and morphogenesis, which in turn contribute to the growth and spread of cancer cells including breast cancer cells. It has been suggested that HGF might directly or indirectly mediate chemotactic cell movement, namely chemotaxis. Here, we investigated the impact of HGF on the expression of the chemokine family, including the CCL (C-C Motif Chemokine Ligands) family and the CXCL (C-X-C Motif Chemokine Ligands) family and the subsequent consequence of these chemokines on endothelial and cancer cells. Method. Human recombinant hepatocyte growth factor and human recombinant CCLs were used in the study. Human vascular endothelial cells were challenged with HGF and their gene expression was profiled using gene microarray technology. The effects of the responsive chemokines were further tested on endothelial cells and the expression of the respective CCLs was knocked down in endothelial cells by way of siRNA. The impact on the paracellular permeability was assessed by PCP (paracellular permeability) assay using a fluorescence tracer and by transendothelial electrical resistance (TER). TER and cellular migration were also evaluated using automated electric cell substrate impedance sensing (ECIS) methods. Results. Within the concentrations known to induce biological functions in endothelial cells, HGF had a profound upregulatory effect on the expression of multiple chemokines, including CCL14, CCL20, CCL21, CCL28. CXCL family members also responded to HGF, including CXCL8 (p<0.001), CXCL3 (p<0.01), CXCL2 (p=0.01) and CXCL17 (p<0.05). We chose to further investigate the effects of a panel of CCLs which have significant clinical connections in breast cancer, notably CCL20 (otherwise known as LARC, Liver And Activation-Regulated Chemokine). High level CCL20 expression in breast cancer is correlated with a favourable relapse free survival (p=0.0021) of the patients (TCGA database, kmplot.com). CCL20 had a marginal inhibitory effect on the permeability of paracellular space, however, it had profound effects on the migration of cancer cells, seen by a marked increase in cellular migration. A similar stimulatory effect on cancer cells was seen in conditioned media from HGF activated endothelial cells, and partially abolished by siRNA to CCL20. Discussion. HGF exerts an upregulatory effect on the expression of certain chemokines from endothelial cells, which in turn acted on cancer cells by inducing chemotaxic effects. HGF, via regulation of chemokines, may regulate both directional and unidirectional migration of cancer cells, and impact the disease progression in breast cancer. Citation Format: Wenjing Gong, Andrew James Sanders, Tracey Amanda Martin, Yanan Gu, Ping Sun, Wen Guo Jiang. Hepatocyte growth factor regulates the expression of chemokine family in vascular endothelial cells; potential implications in clinical breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS17-54.