PDX Model Establishment and Drug Efficacy

HB214 PDX establishment and drug efficacy studies were performed as described previously^{31 (link),47 (link)}. HB214 tumor fragments were engrafted in the interscapular region of 6–12-week-old female athymic nude mice (Athymic NudeFoxn1nu, ENVIGO, Gannat, France). After latency period, mice bearing tumor of 62–256 mm³ were randomly assigned to each treatment arm according to their tumor volume to obtain homogenous mean and median tumor volume in each arm. The control group was not treated during all the course of the experiment. Irinotecan HCl trihydrate (MedChem, Monmouth Junction, New Jersey) (dissolved in 99% NaCl 0.9%; 2.5 mg/kg) was administrated intraperitoneally daily for five consecutive days per week for three weeks or first for three consecutive days then one day off followed by five consecutive days per week for two weeks. MK-1775 (MedChem) (dissolved in 0.5% Methylcellulose; 60 mg/kg) was administrated orally three time per week for three or four weeks. Treatments were stopped prematurely if toxicity causing >15% body weight loss was observed. Tumor volumes were measured two to three time per week depending on the tumor growth. Tumors diameters (length and width) are measured with a caliper (digimatic Solaire, IP67) and tumor volume (TV) is calculated using the formula TV (mm³) = [length (mm) × width (mm)²]/2, where the length and the width are the longest and the shortest diameters of the tumor measured perpendicularly, respectively. All animals were weighed at tumor measurement time and were observed every day for physical, behavior, and clinical signs. Control and drug-treated tumors were collected for standard protein and paraffin block preparation.