Functional evaluation of germline TP53 variants identified in Brazilian families at-risk for Li-Fraumeni syndrome.

Germline TP53 pathogenic variants can lead to a cancer susceptibility syndrome known as Li-Fraumeni (LFS). Variants affecting its activity can drive tumorigenesis altering p53 pathways and their identification is crucial for assessing individual risk. This study explored the functional impact of TP53 missense variants on its transcription factor activity. We selected seven TP53 missense variants (c.129G > C, c.320A > G, c.417G > T, c.460G > A, c,522G > T, c.589G > A and c.997C > T) identified in Brazilian families at-risk for LFS. Variants were created through site-directed mutagenesis and transfected into SK-OV-3 cells to assess their transcription activation capabilities. Variants K139N and V197M displayed significantly reduced transactivation activity in a TP53-dependent luciferase reporter assay. Additionally, K139N negatively impacted CDKN1A and MDM2 expression and had a limited effect on GADD45A and PMAIP1 upon irradiation-induced DNA damage. Variant V197M demonstrated functional impact in all target genes evaluated and loss of Ser15 phosphorylation. K139N and V197M variants presented a reduction of p21 levels after irradiation. Our data show that K139N and V197M negatively impact p53 functions, supporting their classification as pathogenic variants. This underscores the significance of conducting functional studies on germline TP53 missense variants classified as variants of uncertain significance to ensure proper management of LFS-related cancer risks.

Exploring CDKN1A Upregulation Mechanisms: Insights into Cell Cycle Arrest Induced by NC2603 Curcumin Analog in MCF-7 Breast Cancer Cells.

Breast cancer stands out as one of the most prevalent malignancies worldwide, necessitating a nuanced understanding of its molecular underpinnings for effective treatment. Hormone receptors in breast cancer cells substantially influence treatment strategies, dictating therapeutic approaches in clinical settings, serving as a guide for drug development, and aiming to enhance treatment specificity and efficacy. Natural compounds, such as curcumin, offer a diverse array of chemical structures with promising therapeutic potential. Despite curcumin's benefits, challenges like poor solubility and rapid metabolism have spurred the exploration of analogs. Here, we evaluated the efficacy of the curcumin analog NC2603 to induce cell cycle arrest in MCF-7 breast cancer cells and explored its molecular mechanisms. Our findings reveal potent inhibition of cell viability (IC50 = 5.6 µM) and greater specificity than doxorubicin toward MCF-7 vs. non-cancer HaCaT cells. Transcriptome analysis identified 12,055 modulated genes, most notably upregulation of GADD45A and downregulation of ESR1, implicating CDKN1A-mediated regulation of proliferation and cell cycle genes. We hypothesize that the curcumin analog by inducing GADD45A expression and repressing ESR1, triggers the expression of CDKN1A, which in turn downregulates the expression of many important genes of proliferation and the cell cycle. These insights advance our understanding of curcumin analogs' therapeutic potential, highlighting not just their role in treatment, but also the molecular pathways involved in their activity toward breast cancer cells.

Novel SNPs in the growth arrest and DNA damage-inducible protein 45 alpha gene (GADD45A) associated with meat quality traits in Berkshire pigs.

This study was conducted to evaluate the porcine gene GADD45A (growth arrest and DNA-damage-inducible protein 45 alpha) as a positional candidate controlling quantitative trait loci (QTL) for meat quality traits on chromosome 6 (SSC6). Four exons of the porcine GADD45A gene were defined from cDNA and BAC clone sequences. A total of 4 single nucleotide polymorphisms (SNPs) were identified in porcine GADD45A. The association of these SNPs (g.196A>G, g.392C>A, g.955T>C and g.3247A>T) with meat quality traits was evaluated in 678 Berkshire pigs. The genotype distribution of only one SNP (g.3247A>T) conformed to Hardy Weinberg equilibrium in the pig population analyzed in this study, and the other SNPs were not in Hardy-Weinberg equilibrium. All four SNPs were significantly associated with meat quality traits. Three SNPS (g.196A>G, g.392C>A, and g.955T>C) showed similar significant association patterns for drip loss, cooking loss, meat color (lightness; MC_L and yellowness; MC_B), shear force and water-holding capacity traits. By contrast, g.3247A>T had a different association pattern with other traits such as intramuscular fat content (IMF) and backfat thickness (BF), drip loss, MC_L, and moisture. These findings will provide useful information for genetic characterization or association studies in other pig populations. Additionally, these markers can potentially be applied in pig breeding programs to improve meat quality traits, including IMF and BF.