ABSTRACT
p73 can activate transcription of p53-responsive genes, thereby inhibiting cell growth. An alternative promoter in the TP73 gene gives rise to an N-terminally truncated isoform of p73, ΔNp73, which lacks the transactivation domain of the full length TAp73 protein. TAp73 is considered pro-apoptotic, and ΔNp73 anti-apoptotic. In this study, we overexpressed ΔNp73ß in p53 wild type and p53 mutant colon cancer cell lines and further exposed the cells to cancer therapeutic drug cisplatin. The results showed that cisplatin decreased the protein expression levels of ΔNp73ß in a dose-dependent manner, and both TAp73 and p53 were upregulated after cisplatin treatment. Further, clonogenic potential and cell viability were decreased, and apoptotic cells increased, in p53 mutant and in p53 wild type cells. Cellular viability was significantly higher in ΔNp73ß-cells than mock-transfected cells. However, ΔNp73ß overexpression did not affect the cellular susceptibility to cisplatin. In conclusion, the overexpression of ΔNp73ß increases viability in p53 wild type and p53 mutant colon cancer cells, and cisplatin induces the degradation of ΔNp73ß in a dose-dependent manner.
Subject(s)
Cisplatin/pharmacology , DNA-Binding Proteins/metabolism , Nuclear Proteins/metabolism , Tumor Suppressor Protein p53/metabolism , Tumor Suppressor Proteins/metabolism , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Blotting, Western , Cell Survival/drug effects , Colonic Neoplasms/genetics , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , DNA-Binding Proteins/genetics , Dose-Response Relationship, Drug , HCT116 Cells , HT29 Cells , Humans , Mutation , Nuclear Proteins/genetics , Tumor Protein p73 , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Proteins/geneticsABSTRACT
BACKGROUND: The adaptor protein PINCH is overexpressed in the stroma of several types of cancer, and is an independent prognostic marker in colorectal cancer. In this study we further investigate the relationship of PINCH and survival regarding the response to chemotherapy in colorectal cancer. RESULTS: Paraffin-embedded tissue sections from 251 primary adenocarcinomas, 149 samples of adjacent normal mucosa, 57 samples of distant normal mucosa and 75 lymph node metastases were used for immunohistochemical staining. Stromal staining for PINCH increased from normal mucosa to primary tumour to metastasis. Strong staining in adjacent normal mucosa was related to worse survival independently of sex, age, tumour location, differentiation and stage (p = 0.044, HR, 1.60, 95% CI, 1.01-2.52). PINCH staining at the invasive margin tended to be related to survival (p = 0.051). In poorly differentiated tumours PINCH staining at the invasive margin was related to survival independently of sex, age and stage (p = 0.013, HR, 1.90, 95% CI, 1.14-3.16), while in better differentiated tumours it was not. In patients with weak staining, adjuvant chemotherapy was related to survival (p = 0.010, 0.013 and 0.013 in entire tumour area, invasive margin and inner tumour area, respectively), but not in patients with strong staining. However, in the multivariate analysis no such relationship was seen. CONCLUSIONS: PINCH staining in normal adjacent mucosa was related to survival. Further, PINCH staining at the tumour invasive margin was related to survival in poorly differentiated tumours but not in better differentiated tumours, indicating that the impact of PINCH on prognosis was dependent on differentiation status.
Subject(s)
Adenocarcinoma/mortality , Colorectal Neoplasms/mortality , DNA-Binding Proteins/metabolism , Adaptor Proteins, Signal Transducing , Adenocarcinoma/diagnosis , Adenocarcinoma/metabolism , Adult , Aged , Aged, 80 and over , Biomarkers, Tumor/metabolism , Cell Differentiation , Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/metabolism , Female , Humans , LIM Domain Proteins , Male , Membrane Proteins , Middle Aged , Retrospective Studies , Survival AnalysisABSTRACT
BACKGROUND AND PURPOSE: An exon 2 G4C14-->A4T14 polymorphism in the p73 gene was shown to be related to survival in several types of cancers, including colorectal cancer. The purpose was to investigate if this polymorphism was related to survival in rectal cancer patients with or without preoperative radiotherapy. MATERIALS AND METHODS: DNA extracted from tissue of 138 rectal cancer patients that received preoperative radiotherapy or had surgery alone was typed for the polymorphism by PCR using confronting two-pair primers. RESULTS: Among patients, 69% had GC/GC genotype, 27% had GC/AT and 4% had AT/AT. In the radiotherapy group, patients carrying the AT (GC/AT+AT/AT) allele had stronger expression of p53 (p=0.001) and survivin protein (p=0.03) than those carrying the GC/GC genotype. Further, among patients receiving preoperative radiotherapy the GC/GC genotype tended to be related to better survival (p=0.20). Patients with GC/GC genotype, along with negative p53 and weak survivin expression showed better survival than the other patients (p=0.03), even after adjusting for TNM stage and tumor differentiation (p=0.01, RR, 7.63, 95% CI, 1.50-38.74). In the non-radiotherapy group, the polymorphism was not related to survival (p=0.74). CONCLUSIONS: Results suggest that the p73 G4C14-->A4T14 polymorphism could be one factor influencing outcome of preoperative radiotherapy in rectal cancer patients.
