Maspin acts as an HDAC1 inhibitor by modulating downstream genes in bladder carcinoma cells. (A) RT4_shCOL, RT4_shMaspin, HT_shCOL, HT_shMaspin, T24-DNA, and T24-maspin cells were lysed, and the protein levels of maspin, acetyl-H3, HDAC1, and β-Actin were determined through immunoblot assays. The RT4_shCOL, RT4_shMaspin (B), T24-DNA, and T24-maspin cells (C) were extracted, and the net HDAC activity in the nuclei lysis solution was determined by using the HDAC1 immunoprecipitation and activity assay kit (±SE, n = 3). (D) RT4_shCOL, RT4_shMaspin, HT_shCOL, HT_shMaspin, T24-DNA, and T24-Maspin cells were lysed, and the protein levels of maspin, p21, MMP9, cyclin D1, vimentin, and β-Actin were determined through immunoblot assays. The numbers indicate the ratio of the target gene/β-Actin in relation to RT4_shCOL, HT_shCOL, or T24-DNA cells. (E) The mRNA ratio of maspin, cyclin D1, p21, vimentin MMP9, and MMP2 between HT_shCOL and HT_shMaspin cells was determined using RT-qPCR assays (±SE, n = 3). ** p < 0.01.