Raltitrexed as a synergistic hyperthermia chemotherapy drug screened in patient-derived colorectal cancer organoids

Objective:Organoids have recently been used as in vitro models to screen chemotherapy drugs in combination with hyperthermia treatment in colorectal cancer.Our research aimed to establish a library of patient-derived colorectal cancer organoids to evaluate synergism between chemotherapy drugs and hyperthermia;validate an index of the hyperthermia chemotherapy sensitization enhancement ratio(HCSER)to identify the chemotherapeutics most enhanced by hyperthermia;and recommend chemotherapy drugs for hyperthermic intraperitoneal treatment.Methods:Organoids were grown from cells extracted from colorectal cancer patient samples or colorectal cancer cell lines.Cells from both sources were encapsulated in 3 D Matrigel droplets,which were formulated in microfluidics and phase-transferred into identical cell-laden Matrigel microspheres.The microspheres were seeded in 96-well plates,with each well containing a single microsphere that developed into an organoid after 7 days.The organoids were used to evaluate the efficacy of chemotherapy drugs at both 37℃ as a control and 43℃ for 90 min to examine hyperthermia synergism.Cell viability was counted with 10%CCK8.Results:We successfully established a library of colorectal cancer organoids from 22 patient parental tumors.We examined the hyperthermia synergism of 7 commonly used hyperthermic intraperitoneal chemotherapy drugs.In 11 of the 22 patient organoids,raltitrexed had significant hyperthermia synergism,which was indexed as the highest HCSER score within each patient group.Conclusions:Our results primarily demonstrated the use of patient-derived colorectal cancer organoids as in vitro models to evaluate hyperthermia synergistic chemotherapeutics.We found that hyperthermia enhanced the effect of raltitrexed the most among the common anti-colorectal cancer drugs.