A study of natural IgG antibodies against ATP-binding cassette subfamily C member 3 in oral squamous cell carcinoma

Abstract

Aims: ATP-binding cassette subfamily C member 3 (ABCC3) is involved in multidrug resistance and is overexpressed in some solid tumors. Recent work revealed an increase in circulating anti-ABCC3 antibodies in lung and esophageal cancers. This in vitro study was undertaken to investigate the effects of the natural IgG antibody against the ABCC3-derived peptide antigen on proliferation of oral squamous cell carcinoma (OSCC) cells and augment the development of efficient and effective treatments in patients with OSCC. Subjects and Methods: An in-house enzyme-linked immunosorbent assay was applied to detect anti-ABCC3 IgG antibody in human plasma. Two OSCC cell lines, CAL27 and SCC15, were cultured with 20% plasma either positive or negative for anti-ABCC3 IgG. Cell proliferation was quantified by the CCK-8 method, and cell apoptosis and cell cycle distribution were analyzed by flow cytometry. The expression of the ABCC3 gene in the cell lines was analyzed by reverse transcriptase quantitative real-time polymerase chain reaction. Results: The results showed that plasma anti-ABCC3 IgG significantly inhibited the proliferation of CAL27 cells but not SCC15 cells, although ABCC3 was expressed in both cell lines. The proportion of apoptotic cells was significantly higher in CAL27 cells treated with anti-ABCC3 IgG-positive plasma than in those treated with IgG-negative plasma. Cell cycle progression was arrested in CAL27 cells treated with anti-ABCC3 IgG-positive plasma. Conclusions: Our data suggest that human plasma anti-ABCC3 IgG may be a promising agent in anti-OSCC therapy, although further studies are needed to arrive at a definitive conclusion.