Published online Mar 14, 2018. doi: 10.3748/wjg.v24.i10.1072
Peer-review started: December 2, 2017
First decision: December 27, 2017
Revised: January 2, 2018
Accepted: January 16, 2018
Article in press: January 16, 2018
Published online: March 14, 2018
Hyperthermal intraperitoneal chemotherapy is an option to treat peritoneum invading gastrointestinal cancer. Until now the results of hyperthermal intraperitoneal chemotherapy (HIPEC) treatment are controversy, needing unification in selected parameters of the treatment. In different cancer centers, the procedure varies in time setting, hyperthermia level and different chemotherapy drugs are used.
As HIPEC is widely used in clinical practice, still there is a lack of studies, analyzing the impact of hyperthermia and cisplatin to cancer cells. The cellular response to the treatment is still not clear. There is no clear data defining optimal timing and temperature of the procedure.
Our objective was to analyze gastric, pancreatic and colorectal cancer cells response to hyperthermia and cisplatin treatment regarding viability, change of intracellular cisplatin concentration and apoptosis rate.
We used AGS (gastric cancer), T3M4 (pancreatic cancer) and Caco-2 (colorectal cancer) cells. Mimicking HIPEC procedure, cells were treated with specific to each cell line IC50 dose of cisplatin at the temperature regimens ranging from 37 °C to 45 °C. Treatment lasted for one hour. Later cells were harvested in normothermia, changing cisplatin containing media to fresh one. Immediately after experiment, intracellular cisplatin concentration was measured, using mass spectrometer analysis. For other readouts cells were harvested for 48 hours in normal conditions. MTT test was performed for cellular viability evaluation and isobologram analysis. We used flow cytometry to determine apoptosis change of hyperthermia and cisplatin treatment.
Cells responded to hyperthermia (ranging from 38 °C to 45 °C) in a different manner. Viability of AGS cells was the most hyperthermia-dependent, decreasing by 30% (from 41 °C to 45 °C). Caco-2 cell viability had no change in the interval from 38 °C to 42 °C. Higher temperature regimens dropped its viability rate by 14%-20%. T3M4 cells reacted differently. Viability dropped until 42 °C, but at higher temperature regimens, we observed increase of viability. While in simultaneous hyperthermia and cisplatin treatment, we observed no change of viability until 41 °C in all cancer cells. Higher temperatures inhibited cell growth. Interestingly, we observed peaks of viability in AGS (42 °C, increase by 33%) and T3M4 (43 °C, increase by 32%) cells. Putting all MTT data to isobologram analysis, we observed synergistic, antagonistic, or additive effects of combined treatment. Hyperthermia and cisplatin treatment was strongly antagonistic in AGS cells. In Caco-2 cells we observed synergistic, additive and antagonistic effects of simultaneous treatment. Few combined treatment regimens were additive for T3M4 cells, and remaining antagonistic. Cisplatin induced early apoptosis in Caco-2 and T3M4 cells 1.5-fold and 3.4-fold, respectively. Hyperthermia of 43 °C in addition to cisplatin induced early apoptosis as compared to cells treated in normothermia by 20% in Caco-2 and 19% in T3M4, respectively. Hyperthermia strongly decreased intracellular cisplatin concentration in AGS, Caco-2, and T3M4 cells by 30%, 20%, and 18%, respectively.
Our data suggest that HIPEC conditions have to be cancer type dependent and well revised. Particular temperature regimens can do more harm, than benefit, by activating cell division and growth.
To get better knowledge of hyperthermia and cisplatin treatment effects, future studies should include more cancer cell lines per cancer type. Also, in vivo vehicle should be established.