Figure 3.

Depletion of ABCG1 attenuates growth of tumors. (A) Relative mRNA levels of ABCG1 between the ABCG1-siRNA and the control-siRNA transfected LuM1 cells. The mRNA levels were normalized with the levels of an internal control Hprt1. *P = 0.0183, n = 3. Similar data were obtained from three independent experiments. (B) Western blot showing ABCG1 knockdown in LuM1. The siRNAs were transfected via electroporation. (C) The rate of LuM1 aggregates larger than 1,000 μm² in a 96-well plate. *P = 0.0177, n = 3. Similar data were obtained from three independent experiments. (D) Representative morphologies of tumoroids with or without ABCG1 depletion. Arrows, dead cells dissociated from tumoroids. Arrowheads, gaps between aggregates. Tumoroids in day 5 post-seeding periods were shown. The tumoroids were grown in ultra-low attachment plates. (E) Tumoroid cell growth with or without ABCG1 depletion. Tumoroids were grown in the 3D/stem condition. ***P = 0.0009 (day 6). n = 4 (biological replicates). Similar data were obtained from two independent experiments. (F) Immunohistochemistry showing ABCG1 in tumoroids cultured within 3D/serum or 3D/stem conditions or formed by ABCG1-depleted or control LuM1. Scale bars, 50 μm. ABCG1 positivity was shown on the bottom. Left two photomicrographs were magnified ones of Figure 2C.