Pan-drug and drug-specific mechanisms of 5-FU, irinotecan (CPT-11), oxaliplatin, and cisplatin identified by comparison of transcriptomic and cytokine responses of colorectal cancer cells

Abstract

Colorectal cancer (CRC) caused over 900,000 deaths worldwide in 2020. A majority of late-stage CRC patients are treated with 5-fluorouracil (5-FU) combined with either irinotecan (CPT-11), oxaliplatin, or both. Despite their widespread use, the mechanisms of efficacy and toxicity of these drugs remain incompletely understood. While previous work has investigated cellular responses to these agents individually, we directly compare the transcriptomic and cytokine profiles of HCT116 wild-type and p53−/− colorectal cancer cells treated with these drugs and report pan-drug, drug-specific, drug class-specific, p53-independent, and p53-dependent signatures. We observed downregulation of histone genes by 5-FU (that significantly correlates with improved survival in CRC patients) and upregulation of FOS and ATF3 by oxaliplatin (which may contribute to peripheral neuropathy). BTG2 was identified as a top gene upregulated by all four drugs, suggesting its critical role in the cellular response to chemotherapy in CRC. Soluble TRAILR2 (death receptor 5; DR5) is a decoy receptor for TRAIL, an apoptosis-inducing cytokine. TRAILR2 was down-regulated by oxaliplatin and 5-FU, was not affected by CPT-11, and was increased by cisplatin. There was an increase in IL-8 by oxaliplatin and increase in ferritin by cisplatin which may contribute to cancer cell survival. Novel drug-specific mechanisms of efficacy or toxicity identified in these signatures may be targeted with combination therapies or development of new targeted therapies. Together, the findings here contribute to our understanding of the molecular bases of efficacy and toxicity of chemotherapeutic agents often used for treatment of GI cancer such as CRC.

Differential p53-Mediated Cellular Responses to DNA-Damaging Therapeutic Agents

“…We recently published a study that directly compared the p53 transcriptional response in HCT116 colorectal cancer cells treated with 5-FU, irinotecan, oxaliplatin, or cisplatin at equitoxic doses [ 13 ]. Multiple types of signatures were established including p53-dependent, p53-independent, pan-drug, drug-specific, and drug class-specific.…”

“…SAT1, which plays a critical role in ferroptosis, was upregulated in a p53-dependent, oxaliplatin-specific manner which suggests an oxaliplatin-specific role in this mode of cell death in colorectal cancer cells [ 57 ]. Despite the majority of the response to the drugs being drug-specific, several genes were regulated across 5-FU, irinotecan, oxaliplatin, and cisplatin including BTG2, suggesting a critical role of this DNA damage response protein in the cellular response to chemotherapy in colorectal cancer [ 13 , 58 ]. Many questions remain, including why differences were observed across the similar platinum-based drugs cisplatin and oxaliplatin, and what part of the p53 regulatory network mediates these differential responses.…”

“…TLR3 can play an anti-cancer role by regulating downstream signaling that enhances expression of pro-inflammatory cytokines, chemokines, and interferons [ 56 ]. Our lab’s recent investigation revealed unique, p53-dependent upregulation of TLR3 by irinotecan compared to treatment with 5-FU, oxaliplatin, or cisplatin at equitoxic doses in colorectal cancer cells, suggesting a novel irinotecan-specific impact on the TME [ 13 ]. Furthermore, earlier studies demonstrate that the induction of TLRs varied across treatment with the DNA-damaging agents doxorubicin, 5-FU, ionizing radiation, and UV irradiation as well as across different cell lines [ 78 ].…”

“…This raises the question of alternative p53 transcriptional programs including ferroptosis, regulation of stemness, and metabolism [ 8 ] which may also be induced in a drug-specific manner. In fact, SAT1, which contributes to p53-mediated ferroptosis [ 57 ], was uniquely upregulated by oxaliplatin compared to treatment with 5-FU, irinotecan, or cisplatin in colorectal cancer cells [ 13 ] which indicates a potential unique role of oxaliplatin in this mode of cell death that is distinct from classical p53-mediated apoptosis. Also recognized are non-transcriptional functions of p53 that affect a wide range of cellular processes such as apoptosis, growth suppression, DNA repair [ 94 , 95 ].…”

“…p53 regulates hundreds of target genes [ 8 ] and is controlled by a complex regulatory network [ 9 ], therefore it is not surprising that p53 target gene selection varies across contexts including cell type, tissue type, and treatment type or dose. For example, distinct p53 target induction profiles were observed across the spleen, thymus, and intestine of γ-radiation-treated mice [ 10 , 11 ]; qualitatively different p53 signaling patterns were observed across a panel of twelve cell lines treated with different doses of DNA damage [ 12 ]; and treatment of colorectal cancer cells with either 5-fluorouracil, irinotecan (CPT-11), oxaliplatin, or cisplatin revealed drug-specific p53-dependent gene signatures [ 13 ]. Investigation of these differential p53 responses to DNA-damaging agents across multiple levels of the p53 regulatory network has revealed that p53 target selectivity may be regulated on different levels depending on context [ 14 , 15 ].…”