Gv280 vector

miR-874-3p mimic non-targeting negative control (NC; 5'-ACUACUGAGUGACAGUAGA-3') or miR-874-3p mimic (5'-CUGCCCUGGCCCGAGGGACCGA-3') were inserted into the GV309 vector (Shanghai GeneChem Co., Ltd.); miR-874-3p inhibitor non-targeting NC (5'-CAGUACUUUUGUGUAGUACAA-3') or miR-874-3p inhibitor (5'-UCGGUCCCUCGGGCCAGGGCAG-3') were inserted into the GV280 vector (Shanghai GeneChem Co., Ltd.). For HDAC1 overexpression, the coding sequence of HDAC1 was inserted into the GV358 vector (Shanghai GeneChem Co., Ltd.). The empty vector was used as the NC for HDAC1 overexpression. 293T cells (American Type Culture Collection) were transfected with 20 µg the GV vector (GV309, GV280 or GV358) together with 15 µg pHelper 1.0 and 10 µg pHelper 2.0 vectors (both from Shanghai GeneChem Co., Ltd.) and then cultured at 37˚C in a humidified incubator in an atmosphere of 5% CO₂ for 48 h to produce lentiviral particles. Transduction was performed when cells were growing exponentially and were 70-80% confluent. Polybrene (8 µg/ml, Sigma-Aldrich; Merck KGaA) and appropriate lentiviral particles (10⁸ TU/ml, 5 µl) were added to cells for 16 h at 37˚C in a humidified incubator in an atmosphere of 5% CO₂. The medium containing lentiviral particles were removed from wells and fresh medium were added. Subsequent experiments were performed 24 h later.