Bevacizumab modulates epithelial-to-mesenchymal transition in the retinal pigment epithelial cells via connective tissue growth factor up-regulation.
OBJECTIVE
To investigate the effect of bevacizumab treatment on connective tissue growth factor (CTGF) expression and the induction of epithelial-to-mesenchymal transition in ARPE-19 cells and human donor retinal pigment epithelium (HRPE) cells in vitro.


METHODS
We quantitated the protein and gene expression level of CTGF by ELISA. The effect of Fc-Fc receptor (Fc-FcR) interaction on CTGF expression was evaluated by CD64 siRNA silencing. Expression of epithelial-to-mesenchymal transition markers, alpha-smooth muscle actin (α-SMA) and zona occludens protein (ZO-1) was evaluated by Western blot. Cell migration and collagen gel contraction assay were examined by light microscopy, and collagen production was measured by ELISA.


RESULTS
Bevacizumab stimulation increased CTGF expression in ARPE-19 and HRPE cells in a dose-dependent manner. CD64 gene silencing inhibited the effect of bevacizumab-induced CTGF up-regulation. Bevacizumab increased the expression of α-SMA and decreased the expression of ZO-1 in ARPE-19 cells. Bevacizumab also caused the release of type-1 collagen and increased cell migration and contraction of collagen.


CONCLUSIONS
Bevacizumab exerts pro-fibrotic effects on human RPE cells at clinical doses by up-regulation of CTGF expression via an Fc-FcR interaction. This effect of bevacizumab may be one of the underlying mechanisms involved in age-related macular degeneration therapy or intravitreal bevacizumab-associated complications.
Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan.
Ching-Long
CL
Chen
Chang-Min
CM
Liang
Yi-Hao
YH
Chen
Ming-Cheng
MC
Tai
Da-Wen
DW
Lu
Jiann-Torng
JT
Chen
D000199:Actins / Q000378:metabolism; D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology*; D000068258:Bevacizumab; D015153:Blotting, Western; D002460:Cell Line; D002465:Cell Movement; D024042:Collagen Type I / Q000378:metabolism; D055513:Connective Tissue Growth Factor / Q000235:genetics* / Q000378:metabolism*; D003470:Culture Media; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000502:physiology*; D020868:Gene Silencing; D006801:Humans; D034741:RNA, Small Interfering / Q000235:genetics; D017452:Receptors, IgG / Q000235:genetics; D055213:Retinal Pigment Epithelium / Q000187:drug effects* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
C541116:ACTA2 protein, human; D000199:Actins; D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; D024042:Collagen Type I; D003470:Culture Media; D034741:RNA, Small Interfering; D017452:Receptors, IgG; C569042:TJP1 protein, human; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D062826:Zonula Occludens-1 Protein; D055513:Connective Tissue Growth Factor; D000068258:Bevacizumab