The Effect of Glutathione Peroxidase-1 Knockout on Anticancer Drug Sensitivities and Reactive Oxygen Species in Haploid HAP-1 Cells

Abstract

The role of glutathione peroxidases (GPx) in cancer and their influence on tumor prognosis and the development of anticancer drug resistance has been extensively and controversially discussed. The aim of this study was to evaluate the influence of GPx1 expression on anticancer drug cytotoxicity. For this purpose, a GPx1 knockout of the near-haploid human cancer cell line HAP-1 was generated and compared to the native cell line with regards to morphology, growth and metabolic rates, and oxidative stress defenses. Furthermore, the IC50 values of two peroxides and 16 widely used anticancer drugs were determined in both cell lines. Here we report that the knockout of GPx1 in HAP-1 cells has no significant effect on cell size, viability, growth and metabolic rates. Significant increases in the cytotoxic potency of hydrogen peroxide and tert-butylhydroperoxide, the anticancer drugs cisplatin and carboplatin as well as the alkylating agents lomustine and temozolomide were found. While a concentration dependent increases in intracellular reactive oxygen species (ROS) levels were observed for both HAP-1 cell lines treated with either cisplatin, lomustine or temozolamide, no significant enhancement in ROS levels was observed in the GPx1 knockout compared to the native cell line except at the highest concentration of temozolamide. On the other hand, a ca. 50% decrease in glutathione levels was noted in the GPx1 knockout relative to the native line, suggesting that factors other than ROS levels alone play a role in the increased cytotoxic activity of these drugs in the GPx1 knockout cells.

Tetraploidy‐linked sensitization to CENP‐E inhibition in human cells

“…A previous study reported a hyperploidy‐selective efficacy of paclitaxel in the haploid‐diploid HAP1 mixed culture at a drug concentration (15 n m ) similar to that observed in this study [ 11 ] (Fig. 2 ), and another study reported an IC 50 value of paclitaxel in HAP1 cells (~ 3 n m ) close to the value obtained in this study [ 44 ] (Fig. 1 ).…”

Comprehensive Evaluation of Biological Effects of Pentathiepins on Various Human Cancer Cell Lines and Insights into Their Mode of Action

“…In particular, the fact that both HAP-1 and the GPx1-negative knockout variant responded similarly throughout the biological assays indicated a negligible impact of GPx1 expression on the cytotoxic mechanism of pentathiepins. Previous studies already compared these two cell lines with regards to their metabolism and antioxidant capacity, including several enzymes and intracellular GSH levels [ 22 ]. Additionally, we detected that catalase was most abundant in HAP-1, HAP-1.KO.GPx1, and the pancreatic cancer cell line DanG.…”

“…However, chemotherapeutic resistance mechanisms have been linked to increased expression of GPx1 [ 21 ]. Moreover, in a recent publication, GPx1 knockout cells proved to be significantly more sensitive to treatment with the chemotherapeutics cisplatin, lomustine, and temozolomide compared with the parental cell line [ 22 ]. Hence, therapeutic inhibition of the GPx1 may be a promising approach for potentiating cancer chemotherapy in drug-resistant cells, one which could be pursued by using pentathiepins.…”

Evaluate the value of prolonging the duration of tiopronin for injection administration in preventing hepatotoxicity

“…Another reported that MDR overexpressing cancer cells were more sensitive to tiopronin than native cells. Thus, tiopronin could find an additional indication in cancer therapy [15] .…”