gms | German Medical Science

Introduction: Peritoneal carcinomatosis (PC) may arise from a variety of tumors but a significant proportion originates from colorectal cancer (CRC). The combination of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) has shown promising results for the treatment of PC of colorectal cancer. CD133+ colon cancer cells represent a highly tumorigenic subpopulation with stem cell characteristics. The goal of our study is to investigate the effects of HIPEC on human colon cancer cells as well as the CD133+ subpopulation in vitro and in vivo.

Material and methods: Human colon cancer cells (HT29) are sorted using the stem cell marker CD133 by flow cytometry. HT29 cells as well as the CD133+ subpopulation are injected in the peritoneal cavity of Balb/c nu/nu mice that will be then subjected to the HIPEC procedure. Upon sacrifice of the animals macroscopic analysis of tumor spread as well as immunohistochemical staining of selected tumor specimen will be performed. In vitro, cell viability using hyperthermia (42°c) combined with different chemotherapies is analyzed.

Results: In vitro the IC50 of different chemotherapies in HT29 as well as CD133 HT29 cells significantly decreased after treatment with hyperthermia (42°c) as compared to normothermia. Pilot in vivo experiments indicated a significant inhibition of PC from HT29 whole cell population using HIPEC compared to repetitive intraperitoneal injection of chemotherapy as already recently described in the literature. The in vivo effects of HIPEC on CD133 colon cancer cell induced peritoneal carcinosis are still under investigation.

Conclusion: So far our results suggest that hyperthermia can significantly increase chemotherapy induced cytotoxicity of HT29 human colon cancer cells as well as their CD133 subpopulation in vitro. There are already promising clinical results regarding the application of HIPEC for therapy of colon cancer peritoneal carcinosis, however, the in vivo effect on the CD133 stem cell like subpopulation needs further evaluation.