Effect of YangZheng XiaoJi Extract, DME-25, on Endothelial Cells and their Response to Avastin

Abstract

Background: Angiogenesis is a cellular process that has been identified as a key target for therapy in solid cancer. However, over the course of anti-angiogenic therapies, cancer cells acquire resistance to these therapies after an initial period of success. DME-25 is an extract from Yang Zheng Xiao Ji, a traditional Chinese medicine that has been reported to benefit patients with cancer by alleviating chemotherapy-associated symptoms and possibly inhibiting key cancer cell traits. This study aimed to explore if DME-25 on its own and in combination with avastin affected endothelial cell behaviour in vitro in the presence of hypoxic lung cancer-conditioned medium (CM). Materials and Methods: Two lung cancer cell lines, A549 and SK-MES-1, were exposed to hypoxic conditions (O₂ ≤1%) for 4 h, after which CM, and RNA were collected. Transcript expression of several influential angiogenic markers in lung cancer cells were assessed following hypoxic/normoxic conditions. Lung cancer CM was added in combination with avastin and DME-25, before or after vascular endothelial growth factor (VEGF) depletion, to endothelial cells (HECV) and cell migration and microtubule formation were assessed in vitro. Results: HECV cell migration was reduced in the presence of avastin, although less efficiently in the presence of lung cancer CM. A combination of DME-25 and avastin with lung cancer CM significantly reduced HECV cell migration irrespective of culture under hypoxia or normoxia. Depletion of VEGF from the CM reduced the inhibitory capacity of avastin, however, it appeared to have little impact on the anti-angiogenic effects of DME-25. Conclusion: DME-25 inhibits tubule formation irrespectively of the factors secreted by normoxic or hypoxic lung cancer cell CM depleted of VEGF.