Cell culture and reagents

The rat pituitary tumor cell lines GH3 (ATCC CCL-82.1^TM; Manassas, VA) and MMQ (ATCC CCL-10609^TM; Manassas, VA) were purchased from the American Type Culture Collection, cultured in Ham’s F-12K (Kaighn’s) Medium (Gibco, USA, #21127030) supplemented with 2.5% fetal bovine serum (FBS, Gibco, USA, #10100-147), 15% horse serum (HS, Gibco, USA, #16050-122) and 100 U/mL penicillin/streptomycin (Gibco, USA, #15070-063), and incubated in a humidified incubator at 37 °C in 5% (v/v) CO₂.

GH3 cells, a double dicentric marker chromosomes cell line derived from a 7-month-old female Wistar-Furth rat in 1965 [16], which have the advantages of epithelial-like morphological characteristics and possess the ability of tumor formation in nude mice. The growth properties of GH3 cells are loosely adherent with floating clusters. The cells generate growth hormone at a great rate and also produce a small amount of prolactin as well [17, 18].

MMQ cells, a prolactin-secreting clonal pituitary cell line isolated from the 7315a rat pituitary tumor tissue, express functional dopamine 2 receptor (DRD2). Light microscopic examination reveals rounded or irregular tumor cells possessing large spherical nuclei and prominent nucleoli. The cells can exert its tumorigenic ability in nude mice with semisolid medium and the MMQ tumors only increase the levels of serum prolactin without affecting the levels of other pituitary hormones or corticosterone in vivo. MMQ cells grow mainly in the state of suspension [19].

ACT001 was generously provided by Accendatech Co., Ltd. (Tianjin, China) and dissolved in sterile water. The reagents used in this study were shown in Supplementary Table S1.