Molecular Mechanisms of Synergistic Effect of PRIMA-1met and Oxaliplatin in Colorectal Cancer With Different p53 Status

Background: Oxaliplatin (L-OHP), a commonly used chemotherapy drug for colorectal cancer (CRC), is often limited in its long-term efficacy due to its associated toxicity and the development of drug resistance. A notable genetic feature in CRC is the frequent mutation of the p53 gene, which plays a critical role in the tumor suppressor pathway. PRIMA-1met (APR-246, eprenetapopt) is a promising therapeutic agent that restores the DNA-binding functionality of various mutant p53 proteins. This compound has advanced to Phase III clinical trials, and its potential to enhance treatment outcomes in CRC remains of great interest. Our study investigates the potential therapeutic synergy of combining PRIMA-1met with L-OHP in CRC, taking into account the different p53 statuses of the cancer cells.

Methods: To evaluate the effectiveness of the combination treatment, we employed several assays, including the Cell Counting Kit-8 (CCK-8) assay for assessing cell viability and the Chou-Talalay method to calculate the combination index (CI). Additionally, wound healing and colony formation assays were used to assess the impact of L-OHP, PRIMA-1met, and their combination on cancer cell migration and proliferation. Weighted gene co-expression network analysis (WGCNA) was performed on RNA-seq data to uncover key modules and central genes associated with different treatment responses. Furthermore, we utilized a xenograft CRC mouse model to evaluate the in vivo efficacy of the combination therapy.

Results: Our results showed that the combination of PRIMA-1met and L-OHP significantly enhanced cytotoxicity, migration inhibition, and colony formation suppression in CRC cells, regardless of the p53 status. This suggests the potential of this combination therapy to overcome both the toxicity and resistance commonly associated with L-OHP treatment. RNA-seq analysis revealed distinct responses between HCT116 cells with wild-type p53 and DLD-1 cells with mutant p53, highlighting pathway alterations that are central to tumorigenesis. WGCNA further identified critical gene modules and hub genes involved in the response to the combined therapy. In vivo experiments demonstrated that the combination treatment was more effective than PRIMA-1met alone and also reduced the toxicity associated with L-OHP.

Conclusions: In conclusion, our study uncovers the differential molecular mechanisms underlying the combination of PRIMA-1met and L-OHP in CRC cells with both wild-type and mutant p53. The data clearly show that this combined regimen offers a synergistic anti-CRC effect both in vitro and in vivo, and it also provides a protective effect against L-OHP-induced toxicity. These findings highlight the clinical potential of combining PRIMA-1met with L-OHP in CRC treatment, offering a strategy to improve therapeutic efficacy while minimizing adverse side effects. Further clinical trials are warranted to fully explore the potential of this combination therapy in clinical settings.