Project description:The objective of this randomized controlled trial was to evaluate the role colonic self-expanding metal stent (SEMS) placement as a bridge to surgery in patients with acute malignant left-sided colonic obstruction. The study was designed to test the hypothesis that SEMS placement could be effectively and safely used in this group of patients to relieve colonic obstruction thereby allowing safe recovery and medical stabilization before proceeding to elective surgery
Project description:The intestinal epithelium consistently exposes to various injuries and exhibits remarkable regenerative capacity. Although small intestinal regeneration has been extensively investigated, the mechanisms governing colonic regeneration remain poorly understood. Here, we identify irradiation-induced regenerative cells (IRECs), a previously unrecognized colonic enterocyte population, emerges following irradiation injury. IRECs, marked by the gene YuanShangCao (Ysc), undergo dedifferentiation and transition into a stem-like state, contributing to epithelial regeneration. IREC ablation severely impairs colonic repair. Mechanistically, YSC promotes colonic regeneration by preventing the lysosomal degradation of YAP. Furthermore, we demonstrate a critical role of p53 in colonic regeneration by inducing Ysc expression. Together, our findings define IRECs as an irradiation injury-induced enterocyte population that dedifferentiate into stem cells in colon epithelial repair and establish the p53-YSC-YAP axis plays a key role in this process, deepening the understanding of colonic diseases.
Project description:Mice with colonic tumors (chemically induced by AOM/DSS) were treated with Nutlin or control vehicle solution to analyze p53 target gene expression in vivo.
Project description:The p53 tumor suppressor binds DNA cooperatively as a tetramer, mediated by salt-bridge interactions between p53 residues E180 and R181. Variants at the R181 residue are one of the most commonly identified TP53 pathogenic variants by germline genetic testing. We show that families with TP53 p.R181H and p.R181C variants show an attenuated cancer risk phenotype compared to patients with classic Li Fraumeni Syndrome due to hotspot loss of function variants. Despite this phenotype, we find that p53 R181H and R181C variants have reduced ability to bind to p53 promotor target sequences and transactivate p53 target genes. We further show that p53 R181H and R181C retain wild-type p53 structure and tetramerization. In addition, R181-mutant cells undergo apoptosis through wild-type p53 activity at the mitochondria. These results indicate that retention of transcription-independent p53 tumor suppressor function may result in a reduced penetrance cancer risk syndrome in humans.