Epigenetics and its therapeutic potential in colorectal cancer

Effect of surface-engineered AuNPs on gene expression, bacterial interaction, protein denaturation, and toxicology assay: an in vitro and in vivo model

We investigated the in vitro and in vivo uses of pamoic acid functionalized gold nanoparticles (PA@AuNPs), with a focus on determining their safety and potential toxicity in living beings. To test this theory, the bacterial interaction of PA@AuNPs was studied using Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa cultures, as well as the inhibition of the bovine serum albumin (BSA) protein. The real-time polymerase chain reaction (RT-PCR) is used to measure the expression of target genes. PA@AuNPs caused dose-dependent cell death in MDA-MB-231, a triple-negative breast cancer (BC) cell line, with an LC50 of -42.23 μL mL-1. It also caused apoptosis in BC cells. The results indicated that in the early weeks, inflammatory cells (mostly neutrophils and macrophages) penetrated the connective tissue, but in the latter weeks, a substantial number of fibroblasts and fibrocytes were identified. Changes in vascular channels, extravasated red blood cells (RBCs), and necrosis are all indicators of growing tissue pathology. These data could point to a dynamic process including an anti-inflammatory response followed by tissue remodeling or repair. These findings show that PA@AuNPs were not hazardous to the tested Sprague Dawley rats, are highly biocompatible, and can be used in a variety of biological applications.

Differential expression and regulation of ADAD1, DMRTC2, PRSS54, SYCE1, SYCP1, TEX101, TEX48, and TMPRSS12 gene profiles in colon cancer tissues and their in vitro response to epigenetic drugs

Colon cancer (CC) is a significant cause of death worldwide, particularly in Saudi Arabia. To increase the accuracy of diagnosis and treatment, it is important to discover new specific biomarkers for CC. The main objectives of this research are to identify potential specific biomarkers for the early diagnosis of CC by analyzing the expressions of eight cancer testis (CT) genes, as well as to analyze how epigenetic mechanisms control the expression of these genes in CC cell lines. Tissue samples were collected from 15 male patients with CC tissues and matched NC tissues for gene expression analysis. The expression levels of specific CT genes, including ADAD1, DMRTC2, PRSS54, SYCE1, SYCP1, TEX101, TEX48, and TMPRSS12, were assessed using quantitative techniques. To validate the gene expression patterns, we used publicly available CC statistics. To investigate the effect of inhibition of DNA methylation and histone deacetylation on CT gene expression, in vitro experiments were performed using HCT116 and Caco-2 cell lines. There was no detected expression of the genes neither in the patient samples nor in NC tissues, except for TEX48, which exhibited upregulation in CC samples compared to NC tissues in online datasets. Notably, CT genes showed expression in testis samples. In vitro, experiments demonstrated significant enhancement in mRNA expression levels of ADAD1, DMRTC2, PRSS54, SYCE1, SYCP1, TEX101, TEX48, and TMPRSS12 following treatment with 5-aza-2'-deoxycytidine and trichostatin A in HCT116 and Caco-2 cell lines. Epigenetic treatments modify the expression of CT genes, indicating that these genes can potentially be used as biomarkers for CC. The importance of conducting further research to understand and target epigenetic mechanisms to improve CC treatment cannot be overemphasized.

Overexpression of circular RNA hsa_circ_0008621 facilitates colorectal cancer progression and predicts poor prognosis

Aim

To evaluate the potential role of serum and tissue hsa_circ_0008621 as a prognostic biomarker for CRC patients. Focused on the functional role of hsa_circ_0008621 in colorectal cancer (CRC).

Methods

Serum and tissue hsa_circ_0008621 expression were quantified by qRT-PCR in 157 CRC patients, as well as 100 serums from healthy controls. Serum and tissue hsa_circ_0008621 expression was evaluated for their prognostic role in CRC patients using Kaplan-Meier curves and Multivariate Cox proportional hazards analysis. To further characterize the biological role of hsa_circ_0008621 expression in CRC, in vitro hsa_circ_0008621 inhibition was performed and the effects on cellular growth, migration, invasion, apoptosis, and glycolysis were explored. Next, the downstream molecules for hsa_circ_0008621 were predicted.

Results

Hsa_circ_0008621 expression was significantly upregulated in CRC tissues and serums. Serum hsa_circ_0008621 levels were significantly up-regulated in advanced-staged samples. High serum hsa_circ_0008621 expression was associated with shorter overall survival and recurrence-free survival in CRC patients. Multivariate Cox regression analysis identified a high level of serum hsa_circ_0008621 expression as an independent prognostic factor with respect to overall survival and recurrence-free survival. Loss of function assays for hsa_circ_0008621 in vitro led to a significant decrease in cell proliferation, migration, invasion, and glycolysis, but an increase in cell apoptosis. Hsa_circ_0008621 can sponge miR-532-5p, which targets SLC16A3.

Conclusion

High level of serum hsa_circ_0008621 is associated with poor survival in CRC and promotes CRC progression, suggesting it to be a promising non-invasive prognostic biomarker and novel therapeutic target in CRC patients.

METTL3-induced circ_0008345 contributes to the progression of colorectal cancer via the microRNA-182-5p/CYP1A2 pathway

BACKGROUND

Circular RNA (circRNAs) have been found to play major roles in the progression of colorectal cancer (CRC). However, the functions of circ_0008345 (transcribed by PTK2) in regulating CRC development remain undefined. In this study, we aimed to explore the roles and underlying mechanisms of circ_0008345 in CRC.

METHODS

RNase R-treated total cellular RNA was used to verify the circular structure of circ_0008345, and a subcellular fractionation assay was performed to detect the subcellular localization of circ_0008345. RNA pull-down and dual-luciferase assays were used to verify the binding relation between microRNA (miR)-182-5p and circ_0008345 and/or CYP1A2. Colony formation assay, EdU, and Transwell assays were performed to detect the biological behavior of CRC cells in vitro, and CRC cells were injected into mice to observe the tumor formation. m6A immunoprecipitation was used to detect the m6A modification of circ_0008345 in CRC cells.

RESULTS

Circ_0008345, upregulated in CRC tissues and cells, was mainly present in the cytoplasm. Circ_0008345 bound to miR-182-5p, and miR-182-5p targeted CYP1A2, an oncogene in CRC. The colony formation, mobility, EdU-positive cell rate in vitro, and tumor growth in mice were inhibited after the knockdown of circ_0008345. However, the suppressing effects of sh-circ_0008345 on CRC and CYP1A2 expression were significantly reversed after further knockdown of miR-182-5p. METTL3 was the m6A modifier mediating circ_0008345 expression, and the suppression of METTL3 reduced the expression of circ_0008345.

CONCLUSIONS

METTL3-dependent m6A methylation upregulated circ_0008345, which blocked the inhibitory effect of miR-182-5p on CYP1A2, thereby exacerbating the malignant phenotype of CRC cells.

Recent progress of targeted nanocarriers in diagnostic, therapeutic, and theranostic applications in colorectal cancer

Cancer at the lower end of the digestive tract, colorectal cancer (CRC), starts with asymptomatic polyps, which can be diagnosed as cancer at a later stage. It is the fourth leading cause of malignancy-associated mortality worldwide. Despite progress in conventional treatment strategies, the possibility to overcome the mortality and morbidity issues with the enhancement of the lifespan of CRC patients is limited. With the advent of nanocarrier-based drug delivery systems, a promising revolution has been made in diagnosis, treatment, and theranostic purposes for cancer management. Herein, we reviewed the progress of miniaturized nanocarriers, such as liposomes, niosomes, solid lipid nanoparticles, micelles, and polymeric nanoparticles, employed in passive and active targeting and their role in theranostic applications in CRC. With this novel scope, the diagnosis and treatment of CRC have proceeded to the forefront of innovation, where specific characteristics of the nanocarriers, such as processability, flexibility in developing precise architecture, improved circulation, site-specific delivery, and rapid response, facilitate the management of cancer patients. Furthermore, surface-engineered technologies for the nanocarriers could involve receptor-mediated deliveries towards the overexpressed receptors on the CRC microenvironment. Moreover, the potential of clinical translation of these targeted miniaturized formulations as well as the possible limitations and barriers that could impact this translation into clinical practice were highlighted. The advancement of these newest developments in clinical research and progress into the commercialization stage gives hope for a better tomorrow.

The landscape of histone modifications in epigenomics since 2020

Histone proteins are a primary component of chromatin; therefore, any modifications to their structure are anticipated to affect the behavior of our genetic material, which is manifested in the form of phenotypic changes at a molecular, cellular or organic level. The majority of histone modifications are of either methylation or acetylation type that regulate gene expression. Though, not all of these modifications are concerned with the direct regulation of gene transcription. Throughout its 13-year run, Epigenomics has never ceased to cover these most gripping epigenetic stories, a significant proportion of which is in the matter of histones and their modifications. As such, the current perspective piece is intended to highlight original histone-oriented contributions published in Epigenomics since 2020.

Analysis of SDC2 gene promoter methylation in whole blood for noninvasive early detection of colorectal cancer

Objectives

Considering the limitations of the current approaches to colorectal cancer (CRC) screening, scientists strived to find noninvasive and more powerful biomarkers for the early diagnosis of CRC. Nowadays, there are different sources of biomarkers for CRC diagnosis. Blood-based samples including circulating cell-free tumor DNA (ctDNA) and DNA extracted from leukocytes in peripheral blood might be promising sources of noninvasive cancer biomarkers such as cancer-specific methylation patterns. In this study, we aimed to evaluate the noninvasive early diagnosis of CRC via quantitative promotor methylation analysis of SDC2 gene in whole blood.

Materials and Methods

Sixty-five CRC patients and 65 healthy participants were enrolled to assess promoter methylation of SDC2 gene in whole blood using the methylation quantification endonuclease-resistant DNA (MethyQESD) technique.

Results

Our findings demonstrated drastic hypermethylation of SDC2 in blood samples from CRC subjects (37.91%) compared with non-malignant individuals (17.02%) (P < 0.001). The sensitivity for detection of CRC by methylation of SDC2 was 81.54%, with a specificity of 69.23%. The ROC curve analysis demonstrated that the AUC was 0.847 (P < 0.001), indicating that the status of SDC2 promoter methylation in whole blood is an excellent biomarker of CRC diagnosis. Furthermore, our results showed that methylation level in CRC patients significantly increased in higher tumor stages, demonstrating that an increased percentage of methylation is correlated with tumor progression (P < 0.001).

Conclusion

SDC2 promoter methylation status in blood samples is a valuable cancer biomarker and holds high power and accuracy in distinguishing CRC patients from healthy subjects in the early stages of the disease.