Retroviral-mediated gene transfer of THAP1 inhibits EC proliferation. (A) Indirect immunofluorescence analysis of HUVECs transduced with pMLV-MCS (HUVEC-MCS) or pMLV-THAP1 (HUVEC-THAP1) retroviral expression vectors, with anti-THAP1 polyclonal antibodies. Nuclei were counterstained with DAPI. (B) Western blot analysis of HUVEC-MCS and HUVEC-THAP1 with anti-THAP1 polyclonal antibodies or anti–αtubulin (loading control) mouse monoclonal antibody. (C) Analysis of cell proliferation in HUVEC-MCS and HUVEC-THAP1. Expression of THAP1 results in inhibition of EC proliferation. (D) TUNEL labeling of apoptotic nuclei in HUVECs transduced with pMLV-MCS (HUVEC-MCS) or pMLV-THAP1 (HUVEC-THAP1) retroviral expression vectors, and incubated in low-serum media for 24 hours. Nuclei were counterstained with DAPI. (E) Apoptosis levels were quantified in HUVEC-MCS and HUVEC-THAP1 incubated in high-serum (20% FCS) or low-serum (0.5% FCS) media for 24 hours. TUNEL labeling of apoptotic nuclei was performed at day 4 after infection and at least 500 cells were counted for each condition. Results are mean and SD of 2 independent retroviral transduction experiments.