RESUMO
Poorly differentiated esophageal adenocarcinoma (PDEAC) has a dismal prognosis. Glypican-1(GPC-1) is known to be upregulated in several cancer types in contrast to healthy tissues, rendering it as a biomarker. Nevertheless, the potential therapeutic targeting of GPC-1 has not been explored in PDEAC. There is accumulating evidence that GPC-1, via upregulation of PI3K/Akt/ERK signaling, plays a crucial role in the progression and chemoresistance in cancer. Pictilisib, a class I pan PI3K inhibitor, has shown promising antitumor results in clinical trials, however, has not gained widespread success due to acquired drug resistance. This study investigated the role of GPC-1 in chemo-resistant PDEAC and appraises the impact of targeted silencing of GPC-1 on the antitumor effects of Pictilisib in PDEAC cell lines. Immunohistochemistry assays in PDEAC tissue specimens demonstrated a pronounced intensity of staining with GPC-1. Upregulation of GPC-1 was found to be correlated with advanced stage and poor prognosis. In-vitro studies examined the influence of GPC-1 knockdown and Pictilisib, both as individual agents and in combination, on cytotoxicity, cell cycle distribution, apoptosis, and gene expression profiles. Silencing GPC-1 alone showed significantly reduced cell viability, migration, colony formation, epithelial-mesenchymal transition, and stemness in PDEAC cells. Significantly, knockdown of GPC-1 combined with low-dose Pictilisib led to enhancement of cytotoxicity, cell cycle arrest, and apoptosis in ESO-26 and OE-33 cells. In the xenograft mouse model, the combination of Pictilisib and GPC-1 knockdown exhibited synergy. These findings suggest that GPC-1 represents a promising target to augment chemosensitivity in esophageal adenocarcinoma.
RESUMO
BACKGROUND/AIM: The primary mode of therapy for individuals with locally advanced esophageal adenocarcinoma (EAC) is neoadjuvant chemotherapy, commonly 5-Fluorouracil (5-FU). However, approximately 30% of these patients develop resistance to therapy. Glypican-1 (GPC-1) has been identified as one of the key drivers of chemoresistance in cancer; however, its role in EAC cells has not been explored. The objective of the present study was to evaluate the role of GPC-1 in chemoresistance to 5-FU in EAC cells. MATERIALS AND METHODS: Cell viability to 5-FU was measured with CCK-8 assay, and GPC-1 expression was validated using western blot. 5-FU resistant cell lines were generated. The effect of lentivirus-mediated GPC-1 knockdown on FLO-1 cell viability, cell cycle, and apoptosis was evaluated. RESULTS: 5-FU resistant EAC cells showed increased GPC-1 expression and knockdown of GPC-1 increased cell death and apoptosis. Importantly, the knockdown of GPC-1 enhanced the antitumor effects of 5-FU in vitro via down-regulating AKT/ERK/ß-catenin signaling. CONCLUSION: Silencing GPC-1 has the potential to augment the efficacy of 5-FU chemotherapy in resistant EAC tumors.
