RHBDD1 Promotes the Growth and Stemness Characteristics of Gastric Cancer Cells by Activating Wnt/β-catenin Signaling Pathway

Backgrounds: Gastric cancer (GC) is threatening public health, with at least one million new cases reported each year. Rhomboid domain-containing protein 1 (RHBDD1) has been identified to regulate the proliferation, migration, and metastasis of cancer cells. However, the role of RHBDD1 in GC has not been elucidated. Objects: This study aimed to investigate the role of RHBDD1 on the growth, metastasis, and stemness characteristics of GC. Methods: RHBDD1 expression was analyzed from the TCGA databank. qRT-PCR was conducted to evaluate the transcription level of RHBDD1. Western blots were used to evaluate the protein expression of RHBDD1, CD133, CD44, Nanog, beta-catenin and c-myc. Colony formation assay and transwell assay were conducted to evaluate the growth and metastasis of NCI-N87 cells, respectively. Sphere-forming assay was performed to study the stemness characteristics. The nude mice xenotransplantation model and immunohistochemistry (IHC) were performed to evaluate the growth of GC in vivo. Results: RHBDD1 expression is elevated in GC cells and clinical tissues. RHBDD1 expression is positively associated with cell proliferation and metastasis of GC cells. RHBDD1 knockdown suppresses the expression of CD133, CD44 and Nanog and attenuates sphere-forming ability. RHBDD1 activates the Wnt/beta-catenin pathway via promoting the expression of beta-catenin / c-myc and inducing beta-catenin translocation into nuclear. RHBDD1 knockdown inhibits the growth of GC in nude mice xenotransplantation model. Conclusion: RHBDD1 is highly expressed in GC, and its knockdown inhibits the growth, metastasis and stemness characteristics of GC cells through activating the Wnt/beta-catenin pathway, suggesting that RHBDD1 has the potential to be a novel therapeutic target for GC treatment.