Natural
antibodies have been found to have anti-tumorigenic function. This study was designed to investigate whether natural
IgG antibodies against
vascular endothelial growth factor receptor 1 (VEGFR1) could suppress the growth of
hepatocellular carcinoma (HCC) cells. Three HCC cell lines and A549
lung cancer cells were used for this study. They were grown, respectively, with human plasma positive or negative for anti-VEGFR1
IgG. Cell viability, apoptosis and VEGFR1 gene expression were examined. Three patients with HCC were recruited for a case study. The results showed that plasma anti-VEGFR1
IgG significantly inhibited the proliferation of all three HCC cell lines but not A549 cell line; the proportions of apoptotic cells were significantly higher in HCC cells treated with anti-VEGFR1
IgG positive plasma than those treated with
IgG negative plasma. The expression of the VEGFR1 gene was significantly higher in HCC cells than A549 cells. Of three HCC patients who received transfusion of anti-VEGFR1
IgG positive plasma, two cases with stage B showed a good response to the treatment but one with distant
metastasis did not. Human plasma
IgG against VEGFR1 may be a promising agent for anti-HCC
therapy.