All cells were incubated at 37° C and 5% CO2 and routinely checked for mycoplasma contamination. HeLa cells, which are derived from cervix adenocarcinoma (CCL-2, American Tissue Cell Culture (ATCC)) were cultured in EMEM (SH3024401, Hyclone) supplemented with 10% FBS. 293T cells, which are human embryonic kidney (HEK) cells that express and are transformed with large T antigen (CRL-3216, ATCC) were cultured in DMEM (25–501N, Genesee) with 10% FBS. Tera-1 cells, which originate from metastatic human GCT/teratoma (HTB-105, ATCC) were cultured in McCoy’s 5A (16600–082, Life Technologies) supplemented with 20% cosmic serum (SH3008702, Fisher Scientific).