Unraveling the oncogenic potential of p53 amyloids in colorectal cancer.

e15117 Background: Mutations in the p53 tumor suppressor gene are present in more than 50% of cancers, contributing to tumorigenesis. Recent research has shown that both wild-type and mutant p53 proteins can form amyloid structures, leading to the loss of normal tumor-suppressing functions and the acquisition of gain-of-function (GOF) properties that promote oncogenesis. Certain TP53 mutations stabilize the protein, facilitating its aggregation in the cytoplasm and nucleus. This study explores the structure-function relationship of uncharacterized p53 mutations (R267W, Y220H, G245V) and investigates their role in disrupting oncogenic signaling networks and cellular pathways. Methods: HCT-116(p53 null) cell line was transfected with the wt and mutant p53 plasmids, followed by treatment of amyloid-forming peptide “p8” for amyloid formation in wt p53. Western blotting, qPCR, immunoflourescence, immunoprecipitation, apoptosis, spheroid formation, cell viability, and cell cycle arrest assays were conducted to validate the oncogenic role of p53 amyloids in colorectal cancer (CRC). Transcriptome profiling was conducted to identify perturbed molecular signalling pathways, that induce changes in amyloid-forming and non-amyloid mutants, along with wild-type p53 amyloid. Furthermore, to elucidate the functional implications of p53 mutations and their role in tumorigenesis, we performed structural analysis of wild-type and mutant forms of p53 using Molecular dynamics simulations. Results: It was found that, unlike Y220H, the G245V and R267W p53 mutations form amyloid structures within cells. Our findings indicate that p53 amyloids do not display the tumor suppressive functions of wild-type p53 and also actively promote oncogenic functions in colorectal cancer cells such as EMT, stemness, proliferation, chemoresistance, loss of cell cycle arrest and apoptosis. Transcriptomic analysis further highlighted the signaling pathways disrupted by amyloid-forming mutants and wild-type amyloids, contributing to oncogenesis in colorectal cancer. Additionally, Molecular dynamics simulations revealed the stability of wild-type p53 amyloids and amyloid-forming mutants through analyses of root mean square deviation (RMSD), hydrogen bonding, secondary structure dynamics, and entropy calculations. Conclusions: The oncogenic role of p53 amyloids is emerging as a significant and novel factor in the pathogenesis of colorectal cancer. Targeting p53 amyloids has the potential to enhance prognostic accuracy in treatment-resistant CRC and offers a promising avenue for precision medicine therapies.