Abstract 3133: Glypican-1 is a potential marker of prognosis and involved in chemoresistance of cisplatin in esophageal squamous cell cancer
Authors: Nishigaki Takahiko , Takahashi Tsuyoshi , Serada Satishi , Fujimoto Minoru , Hara Hisashi , Miyazaki Yasuhiro , Makino Tomoki , Kurokawa Yukinori , Yamasaki Makoto , Nakajima Kiyokazu , Takiguchi Shuji , Mori Masaki , Doki Yuichiro , Naka Tetsuji 
Published: July 2016

[Introduction]Despite recent improvements in multi-treatment approaches, including surgery, radiotherapy and chemotherapy, the prognosis for patients with Esophageal squamous cell cancer (ESCC) remains unsatisfactory. In addition, predicting a prognosis and treatment response for ESCC had been constantly being required but remains difficult, even when using the TNM system. We identified Glypican-1(GPC1) as a novel disease specific antigen of ESCC by quantitative proteomic analysis focused on cell surface membrane proteins. GPC1 is one of the cell-surface heparan sulfate proteoglycans which has been reported as a prognostic factor in pancreatic cancer.

[Objectives]This study aimed to clarify correlations between GPC1 expression and the prognosis in patient with ESCC and also reveal the association of GPC1 with the drug resistance to chemotherapeutic agents in squamous cancer cell lines and esophageal cancer patients treated with chemotherapy.

[Methods]ESCC tissues were obtained from 175 patients who underwent esophagectomy at Osaka University Hospital(Osaka, Japan), from 2001 to 2013 and were subjected to immunohistochemistry. We performed immunohistochemical (IHC) assessment using anti-GPC1 antibody and investigated the association between GPC1 expression and the clinicopathological parameters. We divided the patients into two groups such as high expression group (HG) and low expression group (LG). Furthermore, we investigated associations between GPC1 expression and clinical response of neo-adjuvant chemotherapy for patients with ESCC. We established GPC1 knocked out cells of TE-14 using Crisper-Cas9 system and stable GPC1-transfected cells of LK-2(Lung squamous cell carcinoma cell line) using pcDNA3.1-GPC1 plasmid transfection. To investigate the relationship between GPC1 expression and sensitivity to cisplatin (CDDP), we examined sensitivity to CDDP by the WST-8 assay.

[Results]The patients characteristics as follows, age (median) = 64yrs(39-80), gender (Male: Female) = 155:20. By the IHC analysis, 99 patients were classified into HG and 76 were LG. HG patients exhibited a poorer prognosis compared with the LG patients. (p&lt;0.001) In multivariate analyses pT, pN, and GPC1 high expression were became significant prognostic factors (p&lt;0.01).

We clarified there was a significant negative correlation between histological responses and GPC1 expression in patient with neoadjuvant chemo therapy. Furthermore, in vitro experiments showed that the IC50 values for CDDP of GPC1 expressing cells (TE-14 and GPC1 transfected LK-2) were significantly higher than that of GPC1 no-expressing cells (GPC1 knocked out TE-14 and LK-2).

[Conclusion]Our study showed that GPC1 was an independent prognostic factor in esophageal cancer. Furthermore, we showed that GPC1 was a critical molecule for chemoresistance to cisplatin.

Citation Format: Takahiko Nishigaki, Tsuyoshi Takahashi, Satishi Serada, Minoru Fujimoto, Hisashi Hara, Yasuhiro Miyazaki, Tomoki Makino, Yukinori Kurokawa, Makoto Yamasaki, Kiyokazu Nakajima, Shuji Takiguchi, Masaki Mori, Yuichiro Doki, Tetsuji Naka. Glypican-1 is a potential marker of prognosis and involved in chemoresistance of cisplatin in esophageal squamous cell cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3133.