Transposable elements (TEs), once considered genomic "junk", are now recognized as critical regulators of genome function and human disease. These mobile genetic elements-including retrotransposons (long interspersed nuclear elements [LINE-1], Alu, short interspersed nuclear element-variable numbers of tandem repeats-Alu [SVA], and human endogenous retrovirus [HERV]) and DNA transposons-are tightly regulated by multilayered mechanisms that operate from transcription through to genomic integration. Although typically silenced in somatic cells, TEs are transiently activated during key developmental stages-such as zygotic genome activation and cell fate determination-where they influence chromatin architecture, transcriptional networks, RNA processing, and innate immune responses. Dysregulation of TEs, however, can lead to genomic instability, chronic inflammation, and various pathologies, including cancer, neurodegeneration, and aging. Paradoxically, their reactivation also presents new opportunities for clinical applications, particularly as diagnostic biomarkers and therapeutic targets. Understanding the dual role of TEs-and balancing their contributions to normal development and disease-is essential for advancing novel therapies and precision medicine.
Humans ; DNA Transposable Elements/physiology* ; Animals ; Long Interspersed Nucleotide Elements/genetics* ; Neoplasms/genetics* ; Genomic Instability/genetics* ; Endogenous Retroviruses/genetics*

Carcinoma, Non-Small-Cell Lung/genetics* ; Drug Resistance, Neoplasm/genetics* ; ErbB Receptors/metabolism* ; Genomic Instability ; Humans ; Lung Neoplasms/genetics* ; Neoplasm Proteins/metabolism* ; Protein Kinase Inhibitors/therapeutic use*

OBJECTIVE: To assess the association of genomic instability of epithelial cadherin 1 (CDH1) gene and clinicopathological characteristics of gastric cancer. METHODS: In total 120 paraffin-embedded gastric cancer tissue specimen were prepared, and genomic DNA was extracted. The genomic instability of the CDH1 gene was analyzed by immunohistochemistry and silver staining PCR-single-strand conformation polymorphism. RESULTS: The number of information individuals (heterozygotes) was 98 for the D16S752 locus. The detection rates for microsatellite instability (MSI) and loss of heterozygosity (LOH) at the D16S752 locus and the positive rate of CDH1 protein were 19.39%, 16.33% and 51.02%, respectively. The detection rate of MSI in TNM stages I or II was significantly higher than that in stages III or IV (P<0.05) while the detection rate of LOH was significantly lower than that in stages III or IV (P<0.05). The positive rate of CDH1 protein in TNM stages III or IV was significantly lower than that in stages I or II (P<0.05). The detection rate of MSI of cases with lymph node metastasis was significantly lower than that of without lymph node metastasis (P<0.05) while the detection rate of LOH was significantly higher than that without lymph node metastasis (P<0.05). The positive rate of CDH1 protein in patients with lymph node metastasis was significantly lower than that in patients without lymph node metastasis (P<0.05). The positive rate of CDH1 protein in MSI-positive group was significantly higher than that in MSI-negative group (P<0.05), and the positive rate of CDH1 protein in the LOH-positive group was significantly lower than that the LOH-negative group (P<0.05). CONCLUSION The genomic instability of the CDH1 gene is associated with the progression of gastric cancer. MSI at the D16S752 locus may be used as a molecular marker for early gastric cancer, while LOH at this locus mostly occurs in advanced gastric cancer and can be regarded as an effective indicators for malignancy evaluation and prognosis.
Humans ; Stomach Neoplasms/pathology* ; Lymphatic Metastasis ; Cdh1 Proteins/genetics* ; Microsatellite Instability ; Loss of Heterozygosity ; Genomic Instability ; Microsatellite Repeats ; Antigens, CD/genetics* ; Cadherins/genetics*

Lymphoma is one of the most common malignant tumor of the hematologic system. The genome instability is not only an important molecular basis for the development of lymphoma, but also has important value in the diagnosis and prognosis of lymphoma. There are 2 types of genome instability: Microsatellite instability (MSI/MIN) at gene level and chromosomal instability at chromosome level. Through the study on genes associated with lymphoma, the unstable genes associated with lymphoma could be found, meanwhile the mechanism of its occurrence and development of lymphoma could be explored, and the important basis of molecular biology could also be provided in the field of current hot lymphoma precision medical research.
Genomic Instability ; Humans ; Lymphoma/genetics* ; Microsatellite Instability ; Microsatellite Repeats ; Neoplasms

DNA methylation is an epigenetic modification that forms an important regulation mechanism of gene expression in organisms across kingdoms. Aberrant patterns of DNA methylation can lead to plant developmental abnormalities. In this article, we briefly discuss DNA methylation in plants and summarize its functions and biological roles in regulating gene expression and maintaining genomic stability, plant development, as well as plant responses to biotic and abiotic stresses. We intended to provide a concise reference for further understanding of the mechanism of DNA methylation and potential applications of epigenetic manipulation for crop improvement.
Crop Production ; trends ; DNA Methylation ; Epigenesis, Genetic ; Gene Expression Regulation, Plant ; Genomic Instability ; Plants ; genetics ; Research ; trends ; Stress, Physiological

DNA damage response (DDR) is essential for maintaining genome stability and protecting cells from tumorigenesis. Ubiquitin and ubiquitin-like modifications play an important role in DDR, from signaling DNA damage to mediating DNA repair. In this report, we found that the E3 ligase ring finger protein 126 (RNF126) was recruited to UV laser micro-irradiation-induced stripes in a RNF8-dependent manner. RNF126 directly interacted with and ubiquitinated another E3 ligase, RNF168. Overexpression of wild type RNF126, but not catalytically-inactive mutant RNF126 (CC229/232AA), diminished ubiquitination of H2A histone family member X (H2AX), and subsequent bleomycin-induced focus formation of total ubiquitin FK2, TP53-binding protein 1 (53BP1), and receptor-associated protein 80 (RAP80). Interestingly, both RNF126 overexpression and RNF126 downregulation compromised homologous recombination (HR)-mediated repair of DNA double-strand breaks (DSBs). Taken together, our findings demonstrate that RNF126 negatively regulates RNF168 function in DDR and its appropriate cellular expression levels are essential for HR-mediated DSB repair.
Carrier Proteins ; metabolism ; Cell Line, Tumor ; DNA Breaks, Double-Stranded ; DNA Repair ; genetics ; DNA-Binding Proteins ; metabolism ; Genomic Instability ; HeLa Cells ; Histones ; metabolism ; Humans ; Nuclear Proteins ; metabolism ; RNA Interference ; RNA, Small Interfering ; genetics ; Signal Transduction ; Tumor Suppressor p53-Binding Protein 1 ; metabolism ; Ubiquitin ; Ubiquitin-Protein Ligases ; genetics ; metabolism ; Ubiquitination

Human mesenchymal stem cells (MSCs) have emerged as attractive cellular vehicles to deliver therapeutic genes for ex-vivo therapy of diverse diseases; this is, in part, because they have the capability to migrate into tumor or lesion sites. Previously, we showed that MSCs could be utilized to deliver a bacterial cytosine deaminase (CD) suicide gene to brain tumors. Here we assessed whether transduction with a retroviral vector encoding CD gene altered the stem cell property of MSCs. MSCs were transduced at passage 1 and cultivated up to passage 11. We found that proliferation and differentiation potentials, chromosomal stability and surface antigenicity of MSCs were not altered by retroviral transduction. The results indicate that retroviral vectors can be safely utilized for delivery of suicide genes to MSCs for ex-vivo therapy. We also found that a single retroviral transduction was sufficient for sustainable expression up to passage 10. The persistent expression of the transduced gene indicates that transduced MSCs provide a tractable and manageable approach for potential use in allogeneic transplantation.
Adolescent ; Animals ; Cell Death/drug effects ; Cell Line, Tumor ; Cell Proliferation/drug effects ; Cell Transformation, Neoplastic/drug effects/pathology ; Child ; Cytosine Deaminase/*genetics/therapeutic use ; Fluorouracil/pharmacology ; Genetic Therapy ; Genomic Instability/drug effects ; Humans ; Karyotype ; Mesenchymal Stromal Cells/*cytology/drug effects/metabolism ; Mice ; Multipotent Stem Cells/cytology/drug effects/metabolism ; Neoplasms/therapy ; Retroviridae/*metabolism ; Time Factors ; *Transduction, Genetic

Genomic instability, which occurs through both genetic mechanisms (underlying inheritable phenotypic variations caused by DNA sequence-dependent alterations, such as mutation, deletion, insertion, inversion, translocation, and chromosomal aneuploidy) and epigenomic aberrations (underlying inheritable phenotypic variations caused by DNA sequence-independent alterations caused by a change of chromatin structure, such as DNA methylation and histone modifications), is known to promote tumorigenesis and tumor progression. Mechanisms involve both genomic instability and epigenomic aberrations that lose or gain the function of genes that impinge on tumor suppression/prevention or oncogenesis. Growing evidence points to an epigenome-wide disruption that involves large-scale DNA hypomethylation but specific hypermethylation of tumor suppressor genes, large blocks of aberrant histone modifications, and abnormal miRNA expression profile. Emerging molecular details regarding the modulation of these epigenetic events in cancer are used to illustrate the alterations of epigenetic molecules, and their consequent malfunctions could contribute to cancer biology. More recently, intriguing evidence supporting that genetic and epigenetic mechanisms are not separate events in cancer has been emerging; they intertwine and take advantage of each other during tumorigenesis. In addition, we discuss the collusion between epigenetics and genetics mediated by heterochromatin protein 1, a major component of heterochromatin, in order to maintain genome integrity.
Biology ; Carcinogenesis ; Chromatin ; DNA ; DNA Methylation ; Epigenomics* ; Genes, Tumor Suppressor ; Genetics* ; Genome ; Genomic Instability ; Heterochromatin ; Histones ; MicroRNAs ; Sequence Deletion

The DNA damage response is critical for cells to maintain genome stability and survival. In this review, we discuss approaches to targeting critical elements of the DNA damage response for radiosensitization and chemosensitization. In addition, we also discuss strategies for targeting DNA damage response and DNA repair defects in cancer cells for synthetic lethality.
Antineoplastic Agents ; therapeutic use ; Cell Death ; DNA Damage ; genetics ; DNA Repair ; genetics ; Dose-Response Relationship, Radiation ; Drug Resistance, Neoplasm ; Genomic Instability ; Humans ; Neoplasms ; drug therapy ; genetics ; pathology ; radiotherapy ; Poly(ADP-ribose) Polymerase Inhibitors ; Poly(ADP-ribose) Polymerases ; pharmacology ; Radiation Dosage

Chromatin ; genetics ; metabolism ; Epigenesis, Genetic ; Genomic Instability ; Histones ; metabolism ; Humans ; Neoplasms ; metabolism ; pathology ; Ubiquitin-Protein Ligases ; genetics ; metabolism