p53 Isoforms as Cancer Biomarkers and Therapeutic Targets

Toxocara Canis Increases the Potential of Breast Cancer by Reducing the Expression of the P53 Protein

INTRODUCTION

Breast cancer is considered the most frequent type of cancer in women with high mortality worldwide, and most importantly, it is the second most common cancer. However, some breast cancer-related risk factors remain unknown. So, the current study was designed to evaluate the effect of Toxocara canis on the biomarkers correlated with proliferation, apoptosis, inflammation, and angiogenesis in 4T1 tumor-bearing mice infected with Toxocara canis for the first time.

METHODS

Mice were categorized into four groups: A) control, B) treated with 4T1+ Toxocara canis, C) treated with Toxocara canis, and D) treated with 4T1. The expression of Ki-67 and P53 was then evaluated by using the immunohistochemical technique. In addition, the levels of transforming growth factor-β, Interferon gamma-γ, Interleukin 10, tumor necrosis factor-α and vascular endothelial growth factor as well as anti- Toxocara canis IgG were determined using the enzyme-linked immunosorbent assay method.

RESULTS

The expression of Ki-67 was significantly increased in the 4T1+ Toxocara canis group than control and Toxocara canis groups (P < 0.001 and P < 0.001, respectively). Moreover, a significant decrease in P53 was found in the 4T1+ Toxocara canis group than in the control and Toxocara canis groups (P < 0.001 and P < 0.001, respectively). Also, the 4T1+ Toxocara canis group significantly reduced the expression of P53 more than 4T1 tumor-bearing mice (P = 0.005). In addition, the 4T1+ Toxocara canis group had an increasing tumor necrosis factor-α and vascular endothelial growth factor than controls (P = 0.004 and P = 0.002, respectively). Furthermore, a significant reduction in Interleukin 10 was found in the 4T1+ Toxocara canis group than in the control group (P = 0.004).

CONCLUSION

Our findings showed that Toxocara canis could probably increase the potential of breast cancer by reducing P53 in 4T1 tumor-bearing mice infected with Toxocara canis more than other groups.

The presence of a G-quadruplex prone sequence upstream of a minimal promoter increases transcriptional activity in the yeast Saccharomyces cerevisiae

Non-canonical secondary structures in DNA are increasingly being revealed as critical players in DNA metabolism, including modulating the accessibility and activity of promoters. These structures comprise the so-called G-quadruplexes (G4s) that are formed from sequences rich in guanine bases. Using a well-defined transcriptional reporter system, we sought to systematically investigate the impact of the presence of G4 structures on transcription in yeast Saccharomyces cerevisiae. To this aim, different G4 prone sequences were modeled to vary the chance of intramolecular G4 formation, analyzed in vitro by Thioflavin T binding test and circular dichroism and then placed at the yeast ADE2 locus on chromosome XV, downstream and adjacent to a P53 response element (RE) and upstream from a minimal CYC1 promoter and Luciferase 1 (LUC1) reporter gene in isogenic strains. While the minimal CYC1 promoter provides basal reporter activity, the P53 RE enables LUC1 transactivation under the control of P53 family proteins expressed under the inducible GAL1 promoter. Thus, the impact of the different G4 prone sequences on both basal and P53 family protein-dependent expression was measured after shifting cells onto galactose containing medium. The results showed that the presence of G4 prone sequences upstream of a yeast minimal promoter increased its basal activity proportionally to their potential to form intramolecular G4 structures; consequently, this feature, when present near the target binding site of P53 family transcription factors, can be exploited to regulate the transcriptional activity of P53, P63 and P73 proteins.

The Important Role of Protein Kinases in the p53 Sestrin Signaling Pathway

p53, a crucial tumor suppressor and transcription factor, plays a central role in the maintenance of genomic stability and the orchestration of cellular responses such as apoptosis, cell cycle arrest, and DNA repair in the face of various stresses. Sestrins, a group of evolutionarily conserved proteins, serve as pivotal mediators connecting p53 to kinase-regulated anti-stress responses, with Sestrin 2 being the most extensively studied member of this protein family. These responses involve the downregulation of cell proliferation, adaptation to shifts in nutrient availability, enhancement of antioxidant defenses, promotion of autophagy/mitophagy, and the clearing of misfolded proteins. Inhibition of the mTORC1 complex by Sestrins reduces cellular proliferation, while Sestrin-dependent activation of AMP-activated kinase (AMPK) and mTORC2 supports metabolic adaptation. Furthermore, Sestrin-induced AMPK and Unc-51-like protein kinase 1 (ULK1) activation regulates autophagy/mitophagy, facilitating the removal of damaged organelles. Moreover, AMPK and ULK1 are involved in adaptation to changing metabolic conditions. ULK1 stabilizes nuclear factor erythroid 2-related factor 2 (Nrf2), thereby activating antioxidative defenses. An understanding of the intricate network involving p53, Sestrins, and kinases holds significant potential for targeted therapeutic interventions, particularly in pathologies like cancer, where the regulatory pathways governed by p53 are often disrupted.

RNA Overwriting of Cellular mRNA by Cas13b-Directed RNA-Dependent RNA Polymerase of Influenza A Virus

Dysregulation of mRNA processing results in diseases such as cancer. Although RNA editing technologies attract attention as gene therapy for repairing aberrant mRNA, substantial sequence defects arising from mis-splicing cannot be corrected by existing techniques using adenosine deaminase acting on RNA (ADAR) due to the limitation of adenosine-to-inosine point conversion. Here, we report an RNA editing technology called "RNA overwriting" that overwrites the sequence downstream of a designated site on the target RNA by utilizing the RNA-dependent RNA polymerase (RdRp) of the influenza A virus. To enable RNA overwriting within living cells, we developed a modified RdRp by introducing H357A and E361A mutations in the polymerase basic 2 of RdRp and fusing the C-terminus with catalytically inactive Cas13b (dCas13b). The modified RdRp knocked down 46% of the target mRNA and further overwrote 21% of the mRNA. RNA overwriting is a versatile editing technique that can perform various modifications, including addition, deletion, and mutation introduction, and thus allow for repair of the aberrant mRNA produced by dysregulation of mRNA processing, such as mis-splicing.

Variation in Fatty Acid Synthase, Ki67 and p53 Esophageal Mucosa Expressions in Barrett's Esophagus Patients Treated for One Year with Two Esomeprazole Different Regimens

Barrett's esophagus (BE) is an acquired pre-malignant condition that results from chronic gastroesophageal reflux. The malignant transformation occurred in 0.5% of patients/year and was independent of medical and endoscopic conservative treatments. Fatty acid synthase (FAS) is a multifunctional enzyme that catalyzes the synthesis of long-chain fatty acids from acetyl-coenzyme A, malonyl-coenzyme A, a reduced form of nicotinamide adenine dinucleotide phosphate (NADPH), and adenosine triphosphate. Activation of FAS is closely linked to malignant transformation. The aim of the present study was to evaluate the variation of FAS, p53, and Ki67 expressions in two groups of 21 BE patients each, after one year of continuous (group A) or discontinuous (group B) treatment with esomeprazole 40 mg/day in comparison to the initial expression. In both the two groups of BE patients, biopsies were taken from pathologic sites of the mucosa for histological and immuno-histochemical detection of FAS, Ki67, and p53 at entry and after one year of Esomeprazole 40 mg treatment. FAS expression was positive when a strong granular cytoplasmic staining was observed in esophageal cells. Ki67 and p53 were defined as positive when nuclear staining was clearly detected at ×10 magnification. FAS expression was reduced in 43% of patients treated with Esomeprazole continuously in comparison to the 10% of patients treated with Esomeprazole on demand (p = 0.002). Ki67 expression was reduced in 28% of continuously treated patients in comparison to 5% of patients treated on demand (p = 0.001). The p53 expression decreased in 19% of continuously treated patients in comparison to an increase in 2 patients (9%) treated on demand (p = 0.05). Continuously Esomeprazole treatment could help in the diminution of metabolic and proliferative activities in the esophageal columnar epithelium and in part it can help prevent the oxidative damage against cellular DNA, resulting in a diminution in p53 expression.

RNA Transcript Diversity in Neuromuscular Research

Three decades since the Human Genome Project began, scientists have now identified more then 25,000 protein coding genes in the human genome. The vast majority of the protein coding genes (>  90%) are multi-exonic, with the coding DNA being interrupted by intronic sequences, which are removed from the pre-mRNA transcripts before being translated into proteins, a process called splicing maturation. Variations in this process, i.e. by exon skipping, intron retention, alternative 5' splice site (5'ss), 3' splice site (3'ss), or polyadenylation usage, lead to remarkable transcriptome and proteome diversity in human tissues. Given its critical biological importance, alternative splicing is tightly regulated in a tissue- and developmental stage-specific manner. The central nervous system and skeletal muscle are amongst the tissues with the highest number of differentially expressed alternative exons, revealing a remarkable degree of transcriptome complexity. It is therefore not surprising that splicing mis-regulation is causally associated with a myriad of neuromuscular diseases, including but not limited to amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), Duchenne muscular dystrophy (DMD), and myotonic dystrophy type 1 and 2 (DM1, DM2). A gene's transcript diversity has since become an integral and an important consideration for drug design, development and therapy. In this review, we will discuss transcript diversity in the context of neuromuscular diseases and current approaches to address splicing mis-regulation.

The Association of Increased Oxidative Stress and Tumor Biomarkers Related to Polyaromatic Hydrocarbons Exposure for Different Occupational Workers in Makkah, Saudi Arabia

INTRODUCTION

Exposure to occupational polyaromatic hydrocarbons (PAHs) is correlated with several adverse effects on human health, including bladder, lung, and skin cancer. The correlation between PAH exposure and oxidative stress and tumor markers needs to be further explored. Therefore, we conducted this study to examine the effect of acute exposure to PAHs on oxidative stress and tumor marker levels in occupational workers during the Hajj season in Makkah.

METHODS

We conducted a cross-sectional study of 105 workers during Hajj; 60 workers were employed in the open air for ≥eight hours/day, exposed them to high levels of considerable traffic and huge crowds, and 45 workers served as our control group who were unexposed and working in a rural area. Using high-performance liquid chromatography, we analyzed participants' urinary 1-hydroxypyrene to determine PAH levels. Oxidative stress markers malondialdehyde (MDA), glutathione S-transferase (GST), and lactate dehydrogenase (LDH) were analyzed in serum using a spectrophotometer. The serum p53 and p21 proteins were analyzed using an enzyme-linked immunosorbent assay. We used IBM SPSS Statistics for Windows, Version 21.0 (IBM Corp., Armonk, NY, USA) to calculate multivariate logistic regression analysis for oxidative stress and tumor markers such as age, working period, and smoking status risk factors. Additionally, we evaluated associations between oxidative stress and tumor markers.

RESULTS

The mean levels of MDA, GST, and LDH were significantly elevated in exposed workers compared to the control group (p<.001). Also, p53 and p21 protein levels were significantly higher in the occupationally exposed group than in the unexposed control group (p<0.05). No significant correlation between age and increased levels of p53 and p21 was found.

CONCLUSIONS

 In our study, PAH exposure is significantly correlated with higher levels of oxidative stress and tumor marker levels in occupational workers. The evaluation of oxidative stress and tumor marker indicators can efficiently identify workers at high risk of PAH exposure and may assist in preventing future health concerns. More biomarkers should be included in other longitudinal studies to address exposure related to different health risks among workers, especially cancer risk. More prospective studies are required to validate diagnostic utilities and efficiencies of different biomarker combinations.

Mechanism of Resveratrol-Induced Programmed Cell Death and New Drug Discovery against Cancer: A Review

Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a polyphenol found in grapes, red wine, peanuts, and apples, has been reported to exhibit a wide range of biological and pharmacological properties. In addition, resveratrol has been reported to intervene in multiple stages of carcinogenesis. It has also been known to kill several human cancer cells through programmed cell death (PCD) mechanisms such as apoptosis, autophagy, and necroptosis. However, resveratrol has limitations in its use as an anticancer agent because it is susceptible to photoisomerization owing to its unstable double bond, short half-life, and is rapidly metabolized and eliminated. Trans-(E)-resveratrol is nontoxic, and has several biological and pharmacological activities. However, little is known about the pharmacological properties of the photoisomerized cis-(Z)-resveratrol. Therefore, many studies on resveratrol derivatives and analogues that can overcome the shortcomings of resveratrol and increase its anticancer activity are underway. This review comprehensively summarizes the literature related to resveratrol-induced PCD, such as apoptosis, autophagy, necroptosis, and the development status of synthetic resveratrol derivatives and analogues as novel anticancer drugs.

The recent advancements in the early detection of cancer biomarkers by DNAzyme-assisted aptasensors

Clinical diagnostics rely heavily on the detection and quantification of cancer biomarkers. The rapid detection of cancer-specific biomarkers is of great importance in the early diagnosis of cancers and plays a crucial role in the subsequent treatments. There are several different detection techniques available today for detecting cancer biomarkers. Because of target-related conformational alterations, high stability, and target variety, aptamers have received considerable interest as a biosensing system component. To date, several sensitivity-enhancement strategies have been used with a broad spectrum of nanomaterials and nanoparticles (NPs) to improve the limit and sensitivity of analyte detection in the construction of innovative aptasensors. The present article aims to outline the research developments on the potential of DNAzymes-based aptasensors for cancer biomarker detection.