Wnt/beta-catenin signaling activation by TIMP1 confers cisplatin-resistant gastric cancer cells to malignant behaviors and epithelial-mesenchymal transition

Objectives: Cisplatin (DDP) remains to be commonly employed in treating gastric cancer (GC) patients, particularly advanced-stage ones. However, acquired resistance to DDP often occurs, which causes a poor prognosis. This study aimed to understand the potential contribution of tissue inhibitor of metalloproteinase 1 (TIMP1) in acquired resistance to DDP in GC. Methods: Bioinformatics analysis was performed to explore the relation of TIMP1 expression with stages and survival rate in GC. The TIMP1 expression between the parental and DDP-resistant GC cell lines were detected by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The effect of TIMP1 on the ability of cells against DDP was elevated by CCK-8, wounding healing, and transwell assays after exposing DDP. The role of TIMP1 in stemness and EMT process was explored through spheres formation assay and detecting stem cell- and EMT-related markers. Finally, the regulation of TIMP1 in Wnt/beta-catenin signaling in DDP-resistant GC cells was also analyzed by western blot. Results: Bioinformatics analysis revealed that TIMP1 is highly expressed and closely related to tumor stage and poor survival in GC. The TIMP1 expression of DDP-resistant GC cell lines was significantly higher than that of the parental one. CCK-8, wounding healing, and transwell assays showed that the tolerance to DDP of DDP-resistant AGS (AGS/DDP) cells was significantly augmented compared with that of parental AGS cells, revealed by increased IC50 and enhanced migration and invasion when exposed to DDP. Stronger stemness and epithelial-mesenchymal transition could be also observed in AGS/DDP cells. These malignant phenotypes were eliminated by silencing TIMP1 but aggravated by overexpressing TIMP1 in AGS/DDP cells. The use of the Wnt/beta-catenin inhibitor could effectively reverse the function of TMIP1 overexpression in AGS/DDP cells, which suggested that the role of TIMP1 in DDP resistance relied on the Wnt/beta-catenin signaling. Conclusions: TIMP1 is an essential regulator of DDP resistance in GC, which may be a potential therapeutic target for cases that are refractory to DDP.