Role of Reactive Oxygen Species in the Abrogation of Oxaliplatin Activity by Cetuximab in Colorectal Cancer

Abstract

Background:The antibody cetuximab, targeting epidermal growth factor receptor (EGFR), is used to treat metastatic colorectal cancer (mCRC). Clinical trials suggest reduced benefit from the combination of cetuximab with oxaliplatin. The aim of this study was to investigate potential negative interactions between cetuximab and oxaliplatin.Methods:Thiazolyl blue tetrazolium bromide (MTT) assay and Calcusyn software were used to characterize drug interactions. Reactive oxygen species (ROS) were measured by flow cytometry and real-time polymerase chain reaction oxidative stress arrays identified genes regulating ROS production. Chromatin immunoprecipitation (ChIP) measured signal transducer and activator of transcription 1 (STAT-1) binding to dual oxidase 2 (DUOX2) promoter. SW48, DLD-1 KRAS wild-type cell lines and DLD-1 xenograft models exposed to cetuximab, oxaliplatin, or oxaliplatin + cetuximab (control [saline]; n = 3 mice per treatment group) were used. Statistical tests were two-sided.Results:Cetuximab and oxaliplatin exhibited antagonistic effects on cellular proliferation and apoptosis (caspase 3/7 activity reduced by 1.4-fold, 95% confidence interval [CI] = 0.78 to 2.11, P = .003) as opposed to synergistic effects observed with the irinotecan metabolite 7-Ethyl-10-hydroxycamptothecin (SN-38). Although both oxaliplatin and SN-38 produced ROS, only oxaliplatin-mediated apoptosis was ROS dependent. Production of ROS by oxaliplatin was secondary to STAT1-mediated transcriptional upregulation of DUOX2 (3.1-fold, 95% CI = 1.75 to 2.41, P < .001). Inhibition of DUOX2 induction and p38 activation by cetuximab reduced oxaliplatin cytotoxicity.Conclusions:Inhibition of STAT1 and DUOX2-mediated ROS generation by cetuximab impairs p38-dependent apoptosis by oxaliplatin in preclinical models and may contribute to reduced efficacy in clinical settings. Understanding the rationale for unexpected trial results will inform improved rationales for combining EGFR inhibitors with chemotherapeutic agents in future therapeutic use.

AMPKα1 confers survival advantage of colorectal cancer cells under metabolic stress by promoting redox balance through the regulation of glutathione reductase phosphorylation

“…Collectively, these results indicated that GSR Thr507 is most likely the inducible phosphorylation substrates of AMPKα1 in CRC cells under glucose deprivation and that it plays critical roles in GSR activity and likely functions accounting for the protective roles of AMPKα1 in cell survival under nutrient stress. AMPKα1 is a potential target in CRC Chemotherapeutic agents were previously reported to induce redox stress in cancer cells [20]. We therefore hypothesized that knockdown of AMPKα1 could sensitize CRC cells to oxaliplatin treatment.…”

Aminooxyacetic acid (AOAA) sensitizes colon cancer cells to oxaliplatin via exaggerating apoptosis induced by ROS

“…As the standard chemotherapy regimens, FOLFOX and XELOX still play an irreplaceable role in the treatment of CRC in advanced stages. Oxaliplatin (OXA), a third-generation platinum drug, is a DNA-interacting agent that disrupts DNA replication and transcription and induces ROS production, promoting apoptosis [2] [3]. Although OXA improves the objective response and median overall survival rates, the main dose-limiting toxicity, peripheral sensory neuropathy and drug resistance still limit its widespread use.…”

HER4 isoform CYT2 and its ligand NRG1III are expressed at high levels in human colorectal cancer

“…At the time of diagnosis, synchronous metastases can be found in almost 20-25% of patients with CRC, and the majority of patients with stage III disease have a poor prognosis within 5 years of diagnosis. The mainstream drugs used for advanced CRC include 5-fluorouracil, capecitabine, oxaliplatin, irinotecan, vascular endothelial growth factor (VEGF) antibody and epidermal growth factor receptor (EGFR) antibody, which may be used as a single agent or in combination in the first or secondary line of therapy (2,3). However, these therapies are limited in application due to their toxic and adverse effects.…”