Goosecoid facilitates the metastasis of pancreatic adenocarcinoma by enhancing EMT and stemness via regulating TGF-β/SMAD2/3 signaling

Pancreatic adenocarcinoma (PAAD) is a highly aggressive malignant tumor of the gastrointestinal tract. Goosecoid (GSC), translated from a homeobox gene, is a protein participating in metastasis of assorted tumors. This study explores the role of GSC implicated in tumor metastasis, in PAAD progression. GSC expression in PAAD tissues and cells were tested by quantitative polymerase chain reaction (PCR) and western blot. GSC mRNA and protein expressions were elevated in PAAD tissues and cells. The impacts of GSC depletion or upregulation on PAAD cell proliferation, migration, invasion, cell cycle, and apoptosis were determined by colony formation assay, transwell assay, and flow cytometry. E-cadherin and N-cadherin expressions were tested through immunofluorescence to evaluate the epithelial-mesenchymal transition (EMT) process. The results showed that GSC depletion notably restrained cell proliferative and migratory capabilities and cell cycle, declined MMP2 and MMP9 activity, suppressed EMT process, and enhanced cell apoptosis. Nevertheless, GSC overexpression showed the opposite functions. Stem cell markers CD44 and CD133 were suppressed by GSC depletion and enhanced by GSC overexpression. Additionally, a sphere formation assay was implemented to test cell stemness. The levels of key proteins on TGF-β signaling were tested by western blot. GSC could activate TGF-β signaling in cells by promoting SMAD2/3 phosphorylation. The pathway inhibitor SIS3 notably counteracted the functions on cell malignant phenotypes induced by GSC overexpression. Moreover, xenograft tumor-bearing mouse models were established using male BALB/c nude mice to explore the effects of GSC knockdown on tumor growth and metastasis <i>in vivo</i>, and we found that GSC knockdown inhibited PAAD tumor growth and metastasis in xenograft models. GSC is expressed at a high level in PAAD and can facilitate PAAD metastasis by enhancing EMT and stemness via regulating TGF-β/SMAD2/3 signaling.