p53 R267W mutation disrupts p21-mediated cell cycle arrest, boosting lung cancer cell proliferation and migration

Pathogenic germline variants in TP53 are central drivers of hereditary tumor predisposition syndromes. While oncogenic mechanisms of hotspot mutations in p53's DNA-binding domain are well-established, the functional consequences of non-hotspot missense mutations remain poorly understood. This study addresses this gap by characterizing the molecular pathogenesis and clinical significance of the p53 non-hotspot mutation p.Arg267Trp (p.R267W), focusing on its impact on lung cancer progression and p21 (CDKN1A) regulation.

Researchers characterized the p53 R267W mutation's impact using non-small cell lung cancer cell models (A549 and NCI-H1299). They performed functional assays including CCK-8 cell proliferation, clonogenic assay, Transwell migration, wound healing assay, qPCR, Western blot, single luciferase reporter assay, and flow cytometry. These techniques assessed the mutation's effect on TP53 target gene (CDKN1A) regulation, tumor-suppressive phenotypes (proliferation, colony formation, migration), and cell cycle arrest capability, comparing R267W mutant cells to wild-type controls.

Experiments confirmed that the p53 R267W mutant does not affect p53 protein stability, hypothesizing impairment results from DNA-binding domain conformational disruption. The mutant TP53 exhibited significantly reduced transcriptional activity (P<0.001), leading to a concomitant reduction in CDKN1A mRNA expression and diminished cell cycle arrest capability compared to wild type. At the tumor-suppressive functional level, the R267W mutant significantly reduced inhibition rates of non-small cell lung cancer cell proliferation, colony formation, and migration relative to wild type (P<0.05). This indicates a clear oncogenic role for this specific non-hotspot mutation.

The R267W variant drives cell cycle dysregulation and malignant phenotypes in lung cancer by disrupting TP53's transcriptional functions.