COL6A1 Inhibits the Malignant Development of Bladder Cancer by Regulating FBN1

Bladder cancer (BLCA) is a prevalent malignancy worldwide with a high recurrence rate. Collagen Type VI Alpha 1 (COL6A1) plays a key role in several cancer types. In this study, we aimed to explore the role of COL6A1 in BLCA. COL6A1 expression in BLCA was determined using The Cancer Genome Atlas database and real-time quantitative polymerase chain reaction (RT-qPCR). Counting Kit-8, wound-healing, and transwell assays were used to assess the effect of COL6A1 on T24 and 5637 cells. Apoptosis in BLCA cell lines was explored using western blotting and flow cytometry. Co-immunoprecipitation was performed to determine interactions between proteins. The role of COL6A1 in tumor growth in nude mice was evaluated by hematoxylin-eosin, immunohistochemical, and terminal deoxynucleotidyl transferase dUTP Nick-End Labeling. In BLCA, COL6A1 expression was downregulated. Moreover, the COL6A1 overexpression suppressed the viability, migration, and invasion, while promoting apoptosis of BLCA cell lines, with increased Caspase-3, Bax, and p53, and decreased Bcl-2. Conversely, silencing of COL6A1 promoted proliferation, migration, and invasion, while inhibiting apoptosis in BLCA cell lines. In vivo, COL6A1 inhibits tumor growth and progression. Fibrillin-1 (FBN1) was positively correlated with COL6A1 expression. COL6A1 could bind to FBN1 in BLCA cell lines. The expression of FBN1 in BLCA cell lines decreased after COL6A1 silencing, whereas COL6A1 overexpression upregulated FBN1 expression. COL6A1 was downregulated and exerted an inhibitory effect on the development of BLCA, and its expression was positively correlated with the expression of FBN1.