Alterations in APC, BECN1, and TP53 gene expression levels in colon cancer cells caused by monosodium glutamate

Colorectal cancer (CRC) is a disease with high incidence worldwide. As of 2018, it is the second leading cause of cancer deaths in the world. In Saudi Arabia, the incidence of this disease has been increasing in the younger population. Both genetic and lifestyle factors may have contributed to its increased incidence and pathogenesis. Monosodium glutamate (MSG) is a food flavor enhancer that can be found in many commercial foods, and it can sometimes be used as a substitute to table salt. MSG has been investigated for its possible genotoxicity, yielding controversial results. In the present study, the effect of MSG on cell viability and its effect on expression of APC, BECN1, and TP53 genes in SW620 and SW480 colon cancer cell lines were studied. TP53 is a tumor suppressor gene that functions in modifying DNA errors and/or inducing apoptosis of damaged cells, and both APC and BECN1 genes are involved in CRC and are of importance in cellular growth and metastasis. Cancer cell viability was analyzed using MTT assay, and the results showed a significant increase in the number of viable cells after 24 h of treatment with MSG with different concentrations (0.5, 1.0, 10, 50, and 100mM). Moreover, gene expression results showed a significant increase in the expression levels of APC and BECN1 under specified conditions in both cell lines; conversely, TP53 showed a significant decrease in expression in SW620 cells. Thus, it can be concluded that MSG possibly confers a pro-proliferative effect on CRC cells.

New mutation of the TP53 gene associated with the hereditary breast cancer in a young Tuvinian woman

Background. The identification of the ethnospecific mutations associated with hereditary breast cancer remains challenging. Next generation sequencing (Ngs) technology fully enables the compilation of germline variants associated with the risk for inherited diseases. Despite the success of the Ngs, up to 20 % of molecular tests report genetic variant of unknown significance (Vus) or novel variants that have never been previously described and their clinical significances are unknown. To obtain extended information about the variants of the unknown significance, it is necessary to use an alternative approach for the analysis of the Ngs data. To obtain extended characteristic about the unknown significance variants, it is necessary to search for additional tools for the analysis of the Ngs data. Material and methods. We reclassified the mutation of the unknown significance using the activedrivedb database that assessed the effect of mutations on sites of post-translational modifications, and the proteinpaint tool that complemented the existing cancer genome portals and provided a comprehensive and intuitive view of cancer genomic data. Results. In this study, we report a 44-year-old tuvinian woman with a family history of breast cancer. Based on the Ngs data, mutational analysis revealed the presence of the lrg_321t1: c.80c>t heterozygous variant in exon 2, which led to the proline to leucine change at codon 27 of the protein. In the dbpubmed database, this mutation was determined as unknown significance due to data limitation. According to the data of the activedriverdb tool, this mutation is located distally at the site of post-translational protein modification, which is responsible for binding to kinases that regulate genes of the cell cycle, etc. (atm, chek2, cdk, mapk). In accordance with proteinpaint tool, the lrg_321t1: c.80c>t mutation is located in functionally specialized transactivation domains and codon of the tp53 gene, where the pathogenic mutation associated with li-Fraumeni syndrome has been earlier described. Conclusion. This report is the first to describe a new variant in the tp53 gene (rs1555526933), which is likely to be associated with hereditary cancer-predisposing syndrome, including li-Fraumeni syndrome, in a tuvinian Bc patient with young-onset and familial Bc.

Somatic Mutations in TP53 Gene in Colombian Patients With Non-melanoma Skin Cancer

Background/Aim: Non-melanoma skin cancer is the most common cancer in the world. Somatic mutations in the TP53 gene are associated with the development of this cancer. To describe mutations in exons 5-8 of the TP53 gene in a sample of Colombian patients with non-melanoma skin cancer. Materials and Methods: One hundred and fifteen patients with non-melanoma skin cancer were included. Exons 5-8 were amplified and analyzed by PCR-High Resolution Melting and Sanger sequencing. Results: Fifty-seven patients with basal cell carcinomas and 58 with squamous cell carcinomas were studied. 16% of patients with basal cell carcinoma and 26% of patients with squamous cell carcinoma had mutations in the TP53 gene. The most frequent mutations were substitutions, while three patients had deletions. The most frequent mutation was p.R158G. Conclusion: The analysis showed that Colombian individuals with non-melanoma skin cancer have genetic TP53 variants different from those reported as recurrent for this disease.

p53 Immunohistochemistry Patterns Are Surrogate Biomarkers for TP53 Mutations in Gastrointestinal Neuroendocrine Neoplasms

Aims. The aim of this study was to establish p53 immunohistochemistry (IHC) patterns to predict TP53 mutations in gastrointestinal neuroendocrine neoplasms (GI-NENs) and to determine whether p53 IHC patterns could be used for the differential diagnosis of neuroendocrine neoplasms. Methods. TP53 gene sequencing and p53 IHC were performed on formalin-fixed paraffin-embedded (FFPE) tissue samples from 92 patients diagnosed with GI-NENs from five medical centers. Results. The cohort included 35 well-differentiated neuroendocrine tumors and 57 poorly differentiated neuroendocrine carcinomas. Gene sequencing revealed 38 wild-type TP53 and 54 TP53 mutations. p53 expression was interpreted as follows: pattern A, p53 was absent from all tumor cells; pattern B, scattered and weak p53 expression in 1-20% of tumor cells; and pattern C was subclassified as pattern C1: variable p53 staining intensity in 21-60% of tumor cells and tumor cell nests with focal strong positive p53 staining and pattern C2: strong p53 staining in more than 60% of tumor cells. p53 IHC patterns were evaluated as a binary classifier where pattern B predicted wild-type TP53, and patterns A and C predicted TP53 mutations. The sensitivity, specificity, and overall accuracy of this binary classification to predict TP53 status were 0.963, 0.868, and 0.924, respectively. p53 IHC patterns were also correlated with TP53 mutation types. Most cases with pattern A harboured loss-of-function (LOF) mutations, whereas patterns B and C tended to indicate wild-type TP53 and gain-of-function (GOF) mutations, respectively. Furthermore, most of the well-differentiated NETs showed pattern B, whereas pattern C2 was more common in poorly differentiated NECs. Finally, staining interpretation between different observers also yielded high reproducibility. Conclusions. p53 IHC patterns may be used as predictors of TP53 gene mutations and therefore could be potential surrogate markers for TP53 mutations in GI-NENs and could distinguish between well-differentiated NETs and poorly differentiated NECs.

Modified Gold Nanoparticles to Overcome the Chemoresistance to Gemcitabine in Mutant p53 Cancer Cells

Mutant p53 proteins result from missense mutations in the TP53 gene, the most mutated in human cancer, and have been described to contribute to cancer initiation and progression. Therapeutic strategies for targeting mutant p53 proteins in cancer cells are limited and have proved unsuitable for clinical application due to problems related to drug delivery and toxicity to healthy tissues. Therefore, the discovery of efficient and safe therapeutic strategies that specifically target mutant p53 remains challenging. In this study, we generated gold nanoparticles (AuNPs) chemically modified with low molecular branched polyethylenimine (bPEI) for the efficient delivery of gapmers targeting p53 mutant protein. The AuNPs formulation consists of a combination of polymeric mixed layer of polyethylene glycol (PEG) and PEI, and layer-by-layer assembly of bPEI through a sensitive linker. These nanoparticles can bind oligonucleotides through electrostatic interactions and release them in the presence of a reducing agent as glutathione. The nanostructures generated here provide a non-toxic and powerful system for the delivery of gapmers in cancer cells, which significantly downregulated mutant p53 proteins and altered molecular markers related to cell growth and apoptosis, thus overcoming chemoresistance to gemcitabine.

Case Report : Li-Fraumeni Syndrome with Central Nervous System Tumors in Two Siblings

Background Li-Fraumeni syndrome (LFS) is a rare autosomal dominant cancer predisposition syndrome caused by germline TP53 gene mutations. It is characterized by high risk of early-onset cancer, and has been confirmed as associated with multiple tumors clinically. So pediatricians should be more alert to LFS in children with tumors. Choroid plexus carcinoma (CPC) is a rare, malignant tumor which account for less than 1% of all central nervous system (CNS) tumors. However, when such tumorigenesis occurs, it is important to be vigilant for the presence of LFS. Case presentation The first patient is a 32-month-old boy admitted for convulsions and then was found intracranial space-occupying lesion. Underwent operation, he was diagnosis as choroid plexus carcinoma (WHO Grade III). After 5 months, his elder sister, a 13-year-old girl, was brought to emergency department for confusion and intermittent convulsions. Surgery was performed immediately after head CT examination found the lesion. The pathology result indicated glioblastoma. Because the siblings of the same family have successively suffered from malignant tumors, we performed genetic testing on this family. TP53 gene mutation occurred in both children of these two cases from their father, and their other brother was not spared either. So the two siblings both met the diagnostic criteria of LFS. Then they all received systematic anti-tumor therapy, and follow-up hitherto. Conclusion Here we reported a rare LFS case that two siblings were inherited the same TP53 germline mutations from their father. They suffered from choroid plexus carcinoma and glioblastoma and were finally diagnosed with LFS. In this LFS family, the primary tumors of the two children were both central nervous system tumors, which were not reported in the previous literature. It is suggested that clinicians should be alert to LFS related tumors, which is helpful for early diagnosis. Timely detection of TP53 gene is an important way for early diagnosis of LFS, especially in children with tumor. The incidence of secondary tumor in LFS patients is significantly higher, and other family members of the LFS patient also have an increased risk of suffering from the tumors. Therefore, early diagnosis and timely tumor surveillance can obtain better therapeutic effect and prognosis for both proband and their family.