A novel human TINP1 gene promotes cell proliferation through inhibition of p53 and p21 expression.

Transforming growth factor (TGF)-β-inducible nuclear protein 1 (TINP1) is a novel gene, which is localized at chromosome 5q13 where frequent abnormalities in hairy cell leukemia (HCL) occur. The present study investigated the effects of TINP1 knockdown or overexpression on the viability and gene expression of various tumor cell lines. siTINP1 was designed to knock down TINP1 expression. Reverse transcription polymerase chain reaction (RT-PCR) and western blotting were performed to assess gene expression; the cell counting kit-8 (CCK-8) assay was used to detect cell viability, and luciferase and flow cytometry assays were used to determine gene activity. TINP1 was widely expressed in various cell lines. In addition, TINP1 siRNA was able to knock down TINP1 expression in HeLa cells. TINP1 overexpression significantly promoted tumor cell proliferation, which may be associated with the downregulation of p53 expression. Furthermore, TINP1 promoted a number of cell lines to the S phase of the cell cycle. TINP1 promotes cell proliferation and significantly reduces p53 and p21 expression.