There are numerous reports describing the direct or indirect cellular toxicity of bevacizumab. In this study, we measured the direct toxicity of bevacizumab and determined its modulation by growth factors in cultured human corneal fibroblasts.
To measure the toxicity of bevacizumab and ranibizumab on corneal fibroblasts, lactate dehydrogenase (LDH) assays, fluorescence-activated cell sorting analyses, and Ki-67 staining were performed. The role of vascular endothelial growth factor (VEGF) in bevacizumab-related toxicity was evaluated after suppression of VEGF expression using small interfering RNA (siRNA) and VEGF receptor inhibition with SU1498. We evaluated alteration of cellular toxicity and anti-angiogenic function of bevacizumab with cotreatment of basic fibroblast growth factor (bFGF) or nerve growth factor (NGF) using human corneal fibroblasts and human umbilical vein endothelial cells (HUVECs).
Application of bevacizumab induced cellular toxicity and delayed proliferation in a dose-dependent manner, but ranibizumab did not cause cellular damage. Elevated LDH observed after bevacizumab treatment was decreased by cotreatment with varying concentrations of fetal bovine serum. However, VEGF cotreatment, VEGF suppression, and VEGF receptor blocking did not influence bevacizumab-induced cell death. Cotreatment of cells with bFGF or NGF and 2 mg/mL bevacizumab reduced LDH elevation. Low-dose bFGF or NGF did not interfere with the antiangiogenic function of bevacizumab as measured by the tube formation assay and MTS (dimethylthiazol-diphenyltetrazolium bromide) assay of HUVECs.
This study determined the cellular toxicity of bevacizumab and its modulation with bFGF or NGF. Cotreatment with bFGF or NGF with bevacizumab reduced cellular damage without interfering with the original antiangiogenic function. Some components of serum have a protective effect on bevacizumab-induced corneal epithelial change.