Silencing Glypican-1 enhances the antitumor effects of Pictilisib via downregulating PI3K/Akt/ERK signaling in chemo-resistant esophageal adenocarcinoma.

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.

Targeting Glypican-1 Reverses Resistance to 5-Fluorouracil in Esophageal Adenocarcinoma Cells.

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.

Glypican 1 promotes proliferation and migration in esophagogastric adenocarcinoma via activating AKT/GSK/ß-catenin pathway.

Background: Glypican 1 (GPC1) is a heparan sulphate proteoglycan cell membrane protein. It is implicated in driving cancers of the breast, brain, pancreas, and prostate; however, its role in esophagogastric cancer (EGAC) remains unexplored. The aim of the study was to investigate and elucidate the molecular mechanistic of GPC1 in human EGAC. Methods: Thirty tissue and 120 microarray sections of EGAC were evaluated with Anti-GPC1 immunohistochemistry. Loss and gain of GPC1 function were performed using lentivirus transfection in EGAC cell lines. Mechanistically, AKT/GSK/ß-catenin pathway was evaluated using AKT inhibitor MK-2206 and Wnt/ß-catenin stimulant LiCl. Results: GPC1 overexpression was found in 102 cases (68%). Overexpression of GPC1 correlated with lymph node metastasis, poor differentiation and decreased overall survival. Lentivirus mediated GPC1 knockdown resulted in decreased cell proliferation, migration, invasion, and colony formation. Knockdown caused G0/G1 cell cycle arrest, increased apoptosis, and reduced epithelial mesenchymal transition (EMT). GPC1 mediated its effects by activation of AKT/GSK/ß-catenin pathway. Conclusions: This is the first descriptive study to decipher the role of GPC1 in EGAC. Our results suggest that GPC1 regulates cell proliferation and growth and may serve as an attractive oncotarget in EGAC.