Oral cancer among Khat users: finding evidence from DNA analysis of nine cancer-related gene mutations

Background Khat leaves contain the alkaloid cathinone. Research shows that khat might provoke toxicity, mutagenicity, as well as carcinogenicity. Methods Two groups were identified as khat abusers and were categorized by abuse time and diagnosis of oral squamous cell carcinoma (OSCC). Here, 41 participants from Group 2 were short-term khat users, and 42 participants were long-term khat users. The control group included 30 healthy individuals. The coding exons included nine cancer-related genes and were analysed. The histopathological research was conducted with H&E staining along with the TP53 protein expression by implementing immunohistochemical analyses. Results Here, 41 short-term khat users carried seven somatic mutations in four out of nine cancer-related genes: 29/41(70.73%) ARID1A, 24/41(58.53%) MLH1, 34/41(82.92%) PIK3CA and 36/41(87.80%) TP53. The 42 long-term khat users incorporated nine somatic mutations in five out of nin ecancer-related genes: 40/42(95.23%) ARID1A, 36/42(85.71%) ARID2, 29/42(69.04%) PIK3CA, 27/42(64.28%) MLH1, and 35/42(83.33%) TP53. Every khat user had somatic mutations related to OSCC affecting the gingiva and the lower lip. TP53 protein expression was confirmed in all immunohistochemical oral tests. Carcinoma was also positive in the histopathological analysis. Conclusions Khat is a mutagenic and carcinogenic plant that provoked OSCC among short-term khat users (<15 years of use) and long-term users (>15 years of use).

TP53 Inhibited AR Signaling Promote Enzalutamide Resistance in LNCaP cell

Background: To perform gene screening and search key knockout gene associated with enzalutamide resistance in LNCaP cells. Methods: Genome-scale CRISPR-Cas9 transfection were done to screen genes associated with enzalutamide resistance in LNCaP cells. Bioinformatic analysis of TP53 and AR expression correlated with prostate adenocarcinoma by using TCGA database. Knockout interfering RNA (shRNA) were synthesized in lentivirus and transfected into LNCaP cells by using Lipofectamine 3000. TP53 and AR detection was performed by using conventional molecular biology methods, such as western blot, RT-PCR and flow cytometer et al. Results: 27 high (NES<-1.7, P<0.01) and 26 low (NES>1.7, P<0.01) expressed genes were identified in enzalutamide resistance Cells. TP53 interacted with AR may play an important role in the development of enzalutamide resistance from PPI and RNA-seq data. Data from TCGA support that patient with TP53&AR low expression endured higher pathology stage, Gleason grades, more disease progress, recurrence, positive lymphnotes examination numbers and more abnormal bones scan results. LNCaP cell dealt with enzalutamide or with TP53 knockout showed inhibited cell cycle at G0~G1, increased apoptosis percentage and also inhibited cell proliferation. Conclusions: Current data support that TP53 protein inhabiting AR signaling promote enzalutamide resistance in LNCaP cell.

Evolutionary Action Score of TP53 Mutations: Integrated Clinico-pathologic And Protein Structural Analysis in Myelodysplastic Syndromes

ABSTRACTTo determine the impact of TP53 mutations on the phenotype and outcome of myelodysplastic syndromes, we quantified the deleterious effects of missense TP53 mutations using the computationally-derived evolutionary action score (higher score indicates worse impact), based on the phylogenetic divergence of the sequence position and amino acid change perturbation, and correlated with clinico-pathologic-genomic features in 270 newly-diagnosed TP53-mutant patients primarily treated with hypomethylating agents. Using recursive partitioning and regression trees, we identified a subset of patients with low-EAp53 mutations (≤52) with improved overall survival (OS) (n=17, 6%) compared to high-EAp53 (n=253, 94%) [median OS, 48 vs. 10 months; p=0.01]. Compared to high-EAp53, low-EAp53 patients had lower cytogenetic complexity, lower TP53 protein expression, lacked multi-allelic TP53 alterations, but had more somatic mutations in other genes. There was no difference in median TP53 variant allele frequency or distribution of R-IPSS. 3D-protein modeling showed clustering of poor-outcome mutations, indicating structural location influences outcome.

Design, Synthesis, and Biological Evaluation of Aromatic Amide-Substituted Benzimidazole-Derived Chalcones. The Effect of Upregulating TP53 Protein Expression

A series of benzimidazole-derived chalcones containing aromatic amide substituent were designed and synthesized. All of the chalcone compounds were tested for their in vitro antitumor activity against human cancer cell lines (HCT116, HepG2, A549, and CRL-5908). The antiproliferative activity of compounds 3, 6, 9, 14, 15, 16 against HCT116 cells was significantly better than that that of 5-Fluorouracil (IC50: 94.63 µM). The antitumor activity of these compounds showed obvious differences between the wild type HCT116 and mutant HCT116 (TP53−/−) cells. A preliminary mechanistic study suggested that these compounds act by upregulating the expression of TP53 protein in tumor cells without inhibiting the MDM2-TP53 interaction.

Mapping of TP53 protein network using Cytoscape software

TP53 acts as a tumor suppressor in cancer. It induces cell cycle arrest or apoptosis in response to cellularstress and damage. p53 gene alteration could cause uncontrolled cell proliferation. In the present study, weused TP53 gene as the seed in the construction of a protein-protein interaction network to identify genesthat might involve in tumorgenesis process with TP53. TP53 protein interaction database was obtainedfrom STRING version 9.1 program. High-throughput experimental data, literature data and hypotheticalstudies have been used to determine the roles of candidate genes in TP53 pathway. A total 500 genes fromSTRING database loaded into Cytoscape version 2.8.3. The 1762 protein interactions were assembled andvisualized in y organic form. We found eight specific non-overlapping clusters of various sizes, whichemerged from the huge network of protein-interactors using MCODE version 1.32 clustering algorithm.Biological Networks Gene Ontology (BiNGO) was used to determine two ontologies (molecular function andbiological process) involved in the protein network. Most of the genes mainly participated in gene andprotein expression, cell signaling and metabolism. A better understanding of the relationship between thegenes could aid in developing prognostic markers and better therapeutic strategies in cancer treatment.

Relevance of TP53 for CLL diagnostics

TP53 disruption in chronic lymphocytic leukaemia (CLL) is a well-established prognostic marker and informs on the appropriate course of treatment for patients. TP53 status is commonly assessed by fluorescence in situ hybridisation for del(17 p) and Sanger sequencing for TP53 mutations. At present, current screening methods for TP53 mutations fail to detect diagnostically relevant mutations potentially leading to inappropriate treatment decisions. In addition, low levels of mutations that are proving to be clinically relevant may not be discovered with current less sensitive techniques. This review describes the structure, function and regulation of the TP53 protein, the mutations found in cancer and CLL, the relevance of TP53 disruption in CLL and the current screening methods for TP53 mutations including next-generation sequencing.