Short tandem repeat analysis

KSHV⁺ human PEL cell lines, BCBL-1 (obtained from NIH AIDS Research & Reference Reagent Program, Rockville, MD, #3233) and BC-3 (obtained from American Type Culture Collection (ATCC), Manassas, VA, CRL-2277), Raji Burkitt lymphoma cells (obtained from Japanese Collection of Research Bioresources Cell Bank (JCRB), Osaka, Japan, #JCRB9012), and B95-8 monkey lymphocytes (obtained from JCRB, #JCRB9123) were maintained in RPMI 1640 (Nacalai Tesque, Kyoto, Japan) supplemented with 10% fetal bovine serum (FBS), penicillin (100 U/mL), and streptomycin (100 μg/mL). Human keratinocytes HaCaT cells (established by Dr. Norbert E. Fusenig [10 (link)] and obtained from Dr. Peter M. Howley of Harvard Medical School) were maintained in DMEM (Nacalai Tesque, Kyoto, Japan) supplemented with 10% FBS serum, penicillin (100 U/mL), and streptomycin (100 μg/mL). All cells were maintained in a humidified incubator at 37 °C and 5% CO₂. Lytic reactivation was performed using 20 ng/mL 12-O-tetradecanoylphorbol-13-acetate (TPA), and 1.5 mM sodium butyrate for BC-3 cells, and 0.6 mM sodium valproate for BCBL-1 cells as reported previously [11 (link), 12 (link)]. The integrity of the cell lines used in this study was confirmed using short tandem repeat analysis (Takara Bio Inc., Shiga, Japan), and the cells were confirmed to be negative for mycoplasma by PCR.

Prostate cancer cell lines, DU145, PC3, and LNCaP were purchased from the American Type Culture Collection (ATCC). LNCaP95 was a generous gift from Dr. Jun O. Luo (Johns Hopkins University, Baltimore, MD, USA). Cells were authenticated by short tandem repeat analysis (Takara Bio Inc., Shiga, Japan) and then tested by DDC Medical (Thermo Fisher Scientific, Waltham, MA, USA) in April 2018, to ensure that the cells were mycoplasma-free. Cells were maintained as monolayer cultures at 37 °C and 5% CO₂. The cell line DU145 was cultured in DMEM supplemented with 10% FBS, PC-3 in RPMI 1640 with 10% FBS, LNCaP in phenol red-free RPMI 1640 with 10% FBS, and LNCaP95 in phenol red-free RPMI 1640 with 10% charcoal stripped serum (CSS). A docetaxel-resistant cell line variant, LNCaP95-DR, was developed over a period of 6 months by exposure to gradually increased concentrations of docetaxel (Sigma-Aldrich, St. Louis, MO, USA). A time-matched parental cell line, LNCaP95-C, was developed in a medium containing vehicle (DMSO) at the corresponding concentration. Finally, LNCaP95-DR cells were maintained in medium containing 15 nM docetaxel.