ΔNp73 and its effector targets promote colorectal peritoneal carcinosis and predict survival.

Peritoneal metastasis of colorectal origin appears in ~10-15% of patients at the time of diagnosis and in 30-40% of cases with disease progression. Locoregional spread through the peritoneum is considered stage IVc and is associated with a poor prognosis. The development of a regional therapeutic strategy based on cytoreductive surgery, and hyperthermic intra-abdominal chemotherapy has significantly altered the course of the disease. Although recent evidence supports the benefits of cytoreductive surgery, the benefits of hyperthermic intra-abdominal chemotherapy are, however, still a matter of debate. Understanding the molecular alterations underlying the disease is crucial for developing new therapeutic strategies. Here, we evaluated the involvement in peritoneal dissemination of the oncogenic isoform of TP73, ΔNp73, and its effector targets in in vitro and mouse models, and in 30 patients diagnosed with colorectal peritoneal metastasis. In an orthotopic mouse model, we observed that tumor cells overexpressing ΔNp73 present a higher avidity for the peritoneum and that extracellular vesicles secreted by ΔNp73-upregulating tumor cells enhance their dissemination. In addition, we identified that tumor cells overexpressing ΔNp73 present with dysregulation of genes associated with an epithelial/mesothelial-to-mesenchymal transition (MMT) and that mesothelial cells exposed to the conditioned medium of tumor cells with upregulated ΔNp73 present a mesenchymal phenotype. Lastly, ΔNp73 and its effector target RNAs were dysregulated in our patient series, there were positive correlations between ΔNp73 and its effector targets, and MSN and ITGB4 (ΔNp73 effectors) predicted patient survival. In conclusion, ΔNp73 and its effector targets are involved in the peritoneal dissemination of colorectal cancer and predict patient survival. The promotion of the EMT/MMT and modulation of the adhesion capacity in colorectal cancer cells might be the mechanisms triggered by ΔNp73. Remarkably, ΔNp73 protein is a druggable protein and should be the focus of future studies. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

In-depth proteomics characterization of ∆Np73 effectors identifies key proteins with diagnostic potential implicated in lymphangiogenesis, vasculogenesis and metastasis in colorectal cancer.

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related death worldwide. Alterations in proteins of the p53-family are a common event in CRC. ΔNp73, a p53-family member, shows oncogenic properties and its effectors are largely unknown. We performed an in-depth proteomics characterization of transcriptional control by ∆Np73 of the secretome of human colon cancer cells and validated its clinical potential. The secretome was analyzed using high-density antibody microarrays and stable isotopic metabolic labeling. Validation was performed by semiquantitative PCR, ELISA, dot-blot and western blot analysis. Evaluation of selected effectors was carried out using 60 plasma samples from CRC patients, individuals carrying premalignant colorectal lesions and colonoscopy-negative controls. In total, 51 dysregulated proteins were observed showing at least 1.5-foldchange in expression. We found an important association between the overexpression of ∆Np73 and effectors related to lymphangiogenesis, vasculogenesis and metastasis, such as brain-derived neurotrophic factor (BDNF) and the putative aminoacyl tRNA synthase complex-interacting multifunctional protein 1 (EMAP-II)-vascular endothelial growth factor C-vascular endothelial growth factor receptor 3 axis. We further demonstrated the usefulness of BDNF as a potential CRC biomarker able to discriminate between CRC patients and premalignant individuals from controls with high sensitivity and specificity.

ΔNp73, TAp73 and Δ133p53 Extracellular Vesicle Cargo as Early Diagnosis Markers in Colorectal Cancer.

The early diagnosis of colorectal cancer is a key factor in the overall survival of the patients. The actual screening programs include different approaches with significant limitations such as unspecificity, high invasiveness, and detection at late stages of the disease. The specific content of extracellular vesicles derived from malignant cells may represent a non-invasive technique for the early detection of colorectal cancer. Here, we studied the mRNA levels of ΔNp73, TAp73, and Δ133p53 in plasma-derived extracellular vesicles from healthy subjects (n = 29), individuals with premalignant lesions (n = 49), and colorectal cancer patients (n = 42). Extracellular vesicles' ΔNp73 levels were already significantly high in subjects with premalignant lesions. Δ133p53 levels were statistically increased in colorectal cancer patients compared to the other two groups and were associated with patients' survival. Remarkably, TAp73 mRNA was not detected in any of the individuals. The evaluation of ΔNp73, Δ133p53 and CEA sensitivity, specificity and AUC values supports ΔNp73 as a better early diagnosis biomarker and CEA as the best to identify advanced stages. Thus, low levels of CEA and a high content of ΔNp73 may identify in screening programs those individuals at higher risk of presenting a premalignant lesion. In addition, Δ133p53 emerges as a potential prognosis biomarker in colorectal cancer.