title: FRZB knockdown upregulates β-catenin activity and enhances cell aggressiveness in gastric cancer.
abstract: Studies have shown that FRZB correlates with gastric tumorigenicity and may play role in regulating the Wnt/β‑catenin signaling pathway. In the present study, we investigated the correlation between FRZB and the Wnt/β‑catenin signaling pathway using gastric cancer tissues and an FRZB‑knockdown gastric cancer cell line model. The protein levels of FRZB and β‑catenin were examined using immunohistochemical staining. FRZB-specific shRNAs were used to generate FRZB‑knockdown MKN45 gastric cancer cells. Cell proliferation assay, suspending culture and Annexin V/PI double staining analysis were used to investigate the role of FRZB knockdown in cell growth. In vitro migration/invasion assays were performed. The expression of Wnt/β‑catenin downstream targets was analyzed by RT-PCR. FRZB mRNA levels showed negative correlation with β‑catenin levels in paired non-tumor and tumor tissues. FRZB protein levels were negatively correlated with β‑catenin levels analyzed by IHC staining. Furthermore, high FRZB protein levels were correlated with membrane localization of β‑catenin. FRZB knockdown increased gastric cancer cell growth in monolayer and soft agar culture; it increased cell aggregates in suspending culture and rendered less apoptosis which indicated increased anti-anoikis growth. FRZB knockdown increased cell migration and invasion and increased the expression of Wnt/β‑catenin downstream targets such as MMP7 and cyclin D1. Our studies revealed that FRZB levels were correlated with β‑catenin subcellular localization. Knockdown of FRZB in gastric cancer cells increased cell growth and migration/invasion which was also accompanied by activation of Wnt/β‑catenin downstream targets. FRZB knockdown may upregulate the Wnt/β‑catenin pathway and promote aggressiveness in gastric cancer.
authors.affiliation: Department of Intensive Care Unit, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, P.R. China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Qin
authors.affiliation: Department of Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, P.R. China.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, P.R. China.
authors.forename: Jianfang
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, P.R. China.
authors.forename: Lu
authors.initials: L
authors.lastname: Zang
mesh_terms: D017209:Apoptosis / Q000235:genetics; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics; D019938:Cyclin D1 / Q000096:biosynthesis; D015972:Gene Expression Regulation, Neoplastic; D006023:Glycoproteins / Q000235:genetics*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D020783:Matrix Metalloproteinase 7 / Q000096:biosynthesis; D009361:Neoplasm Invasiveness / Q000235:genetics*; D034622:RNA Interference; D034741:RNA, Small Interfering; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology*; D015854:Up-Regulation; D051153:Wnt Proteins / Q000096:biosynthesis; D060449:Wnt Signaling Pathway; D051176:beta Catenin / Q000096:biosynthesis*; D000099274:Frizzled-Related Proteins
chemical_list: D019938:Cyclin D1; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D020783:Matrix Metalloproteinase 7; D034741:RNA, Small Interfering; D051153:Wnt Proteins; D051176:beta Catenin; D000099274:Frizzled-Related Proteins; C530104:CCND1 protein, human; C060932:MMP7 protein, human