S1230

All mouse procedures were conducted in accordance with the Fred Hutchinson Cancer Center (FHCC) Institutional Animal Care and Use Committee (IACUC) guidelines and the ARRIVE guidelines. C57BL/6J (BL/6J) mice (000664, JAX) were purchased from the Jackson Laboratory. Injections of organoid cultures for the generation of subcutaneously grafted organoid tumors were conducted as described previously (47 (link)). Typically, 1 × 10⁶ to 2 × 10⁶ cells in a 100-μl suspension of 50% Matrigel (Corning) in phosphate-buffered saline (PBS) were injected into each flank of the mouse. When average tumor diameters of 3 to 5 mm³ were reached, mice were treated with a once daily intraperitoneal injection of vehicle or flavopiridol (5 mg/kg; S1230, Selleck) diluted with 5% dextrose in water solution (600063, Bound Tree Medical) for 21 days. Caliper measurements of tumors and body weights were recorded three times per week.

PDX models were acquired from the NCI PDMR: 8333975-119-r (lot no. CD1183), 463931-005-r (lot no. LS2265), 466636-057-r (lot no. MD0903), and 885724-159-r (lot no. AM1179). Vials of cryopreserved PDX tissue fragments were revived and subsequently repassaged as fresh whole tissue into both NSG (NOD scid gamma) and nude mice (Foxn1^nu). Freshly repassaged tissue was then used for implantation of study cohorts of nude mice (002019, JAX). All work in mice was approved by IACUC (FHCC IACUC protocol 50935-200016). Every PDX model tested negative for human pathogens (IDEXX h-IMPACT panel). An aseptic standardized procedure was used uniformly: ~1- to 2-mm³ PDX tissue chunks (37°C) were rinsed in RPMI, suspended in Matrigel (Corning), and implanted subcutaneously into the right flanks of 6- to 8-week-old female mice (see strain notes above) under isoflurane anesthesia. Preemptive analgesia was provided using buprenorphine SR (0.05 mg/kg). Post-surgically, tumor growth and body condition were monitored, and tumors were measured with electronic calipers. When average tumor diameters of 3 to 5 mm³ were reached, mice were treated with a once daily intraperitoneal injection of vehicle or flavopiridol (5 mg/kg; S1230, Selleck) diluted with 5% dextrose in water solution (600063, Bound Tree Medical) for 21 days. Caliper measurements of tumors and body weights were recorded three times per week.