Search Results (316)

A mutation detection strategy based on mismatch digestion was applied previously in barley seedlings carrying the chloroplast mutator (cpm) genotype through many generations. Sixty-one mutations were detected along with four large indels: a 15 bp insertion in the intergenic region between tRNA^His and rps19 genes, a 620 bp deletion in the psbA gene, a 79 bp deletion in the intergenic region between rpl33 and rps18 genes and a 45 bp deletion in the rps3 gene. The present investigation aims to understand the mechanisms producing the large indels and to better characterize the cpm mutagenic effect. Whole plastome sequencing revealed novel polymorphisms that were identified either in regions not previously examined or in regions that were explored but not detected through celery juice extract (CJE) digestion. The 620 bp deletion in the psbA gene was lethal when homoplastomic, whereas the 45 bp deletion in the rps3 gene did not affect the viability of the seedlings even in homoplastomy. The presence of direct repeats at the borders of large indels suggests that they could have originated by illegitimate recombination because of CPM protein malfunction. A truncated mismatch repair MSH1 protein identified in cpm seedlings suggests that CPM is involved in organellar genome stability maintenance. Full article

Background/Objectives: Colorectal cancer (CRC) remains a leading cause of cancer-related deaths, with notable sex-specific differences in its incidence, diagnosis, and outcomes. Our previous work identified casein kinase 2 alpha (CK2α) as being capable of impairing DNA mismatch repair (MMR) via phosphorylation of MLH1, thereby increasing the tumor mutational burden. This study aimed to investigate sex-specific differences in CK2α protein expression in CRC. Methods: Immunohistochemical (IHC) analysis was performed on 161 CRC tumors and adjacent normal tissues to quantify the CK2α protein levels. A multi-cohort meta-analysis of proteomic and clinical data was conducted to validate our findings and assess the correlations with age, sex, and relevant signaling pathways. Results: Female CRC patients exhibited significantly higher CK2α expression than male patients, which was confirmed in two independent cohorts. Additionally, CK2α expression was positively correlated with age in female but not male patients. Cross-cohort correlation analyses linked CK2α levels with key proteins involved in estrogen receptor signaling and aging, including DEAD-box helicase 5 (DDX5), histone deacetylase 1 (HDAC1), proliferating cell nuclear antigen (PCNA), prohibitin-2 (PHB2), H/ACA ribonucleoprotein complex subunit 2 (NHP2), and dual-specificity mitogen-activated protein kinase kinase 3 (MAP2K3). Conclusions: CK2α is significantly overexpressed in the tumor tissue of female CRC patients and shows a strong age-related correlation. These findings suggest a sex- and age-specific regulatory mechanism potentially influenced by estrogen signaling or menopause. Such dimorphisms underscore the need for sex-specific strategies in CRC biomarker development and therapy. Full article

Background: Blue light (BL) irradiation has been shown to induce photobiomodulation (PBM) in cells. Here, we investigate its influence on cell types involved in wound healing. Methods: Cellular responses of immortalized human keratinocytes (HaCaTs), normal human dermal fibroblasts (NHDFs), and human umbilical vein endothelial cells (HUVECs) after light treatment at 450 nm were analyzed by kinetic assays on cell viability, proliferation, ATP quantification, migration assay, and apoptosis assay. Gene expression was evaluated by transcriptome analysis. Results: A biphasic effect was observed on HaCaTs, NHDFs, and HUVECs. Low-fluence (4.5 J/cm²) irradiation stimulated cell viability, proliferation, and migration. mRNA sequencing indicated involvement of transforming growth factor beta (TGF-β), ErbB, and vascular endothelial growth factor (VEGF) pathways. High-fluence (18 J/cm²) irradiation inhibited these cellular activities by downregulating DNA replication, the cell cycle, and mismatch repair pathways. Conclusions: HaCaTs, NHDFs, and HUVECs exhibited a dose-dependent pattern after BL irradiation. These findings broaden the view of PBM following BL irradiation of these three cell types, thereby promoting their potential application in wound healing and angiogenesis. Our data on low-fluence BL at 450 nm indicates clinical potential for a novel modality in wound therapy. Full article

Replication timing (RT), the temporal order of DNA replication during S phase, influences regional mutation rates, yet the mechanistic basis for RT-associated mutagenesis remains incompletely defined. To identify drivers of RT-dependent mutation biases, we analyzed whole-genome sequencing data from cells with disruptions in DNA replication/repair genes or exposed to mutagenic compounds. Mutation distributions between early- and late-replicating regions were compared using bootstrapping and statistical modeling. We identified 14 genes that exhibit differential effects in early- or late-replicating regions, encompassing multiple DNA repair pathways, including mismatch repair (MLH1, MSH2, MSH6, PMS1, and PMS2), trans-lesion DNA synthesis (REV1) and double-strand break repair (DCLRE1A and PRKDC), DNA polymerases (POLB, POLE3, and POLE4), and other genes central to genomic instability (PARP1 and TP53). Similar analyses of mutagenic compounds revealed 19 compounds with differential effects on replication timing. These results establish replication timing as a critical modulator of mutagenesis, with distinct DNA repair pathways and exogenous agents exhibiting replication timing-specific effects on genomic instability. Our systematic bioinformatics approach identifies new DNA repair genes and mutagens that exhibit differential activity during the S phase. These findings pave the way for further investigation of factors that contribute to genome instability during cancer transformation. Full article

Background: The profile of germline genetic variants among colorectal cancer patients in Panama has not yet been explored. Methods: We recruited 95 patients with colorectal cancer in an Oncology Reference Hospital Unit in the Azuero region of central Panama, which exhibited the highest prevalence of colorectal cancer in Panama. DNA analysis was performed with a panel of 113 genes with germline mutations for cancer (TruSight^® Cancer Sequencing Panel from Illumina, San Diego, CA, USA). Results: Among the 95 cases, 10 pathogenic/likely pathogenic variants (P/LP) were identified in the MUTYH, TP53, CHEK2, PALB2, ATM, and BARD1 genes, representing 10% of the total. The variant 1103G>A (p.Gly368Asp) in MUTYH was the most prevalent. The variant at c.1675_1676delCAinsTG (p.Gln559Ter) in PALB2 is new and is reported for the first time in this study. Variants were most frequently detected in the MUTYH and CHEK2 genes, affecting four and two patients, respectively. Notably, none of the 95 Panamanian patients in the initial colorectal cancer cohort had mutations in mismatch repair (MMR) genes. These genes are among the most frequently mutated in other cohorts around the world. Conclusions: The atypical profile of germline genetic variants in this population may be related to the unique characteristics of the Azuero population in Panama’s central region. This profile may partly explain the high prevalence of colorectal cancer among its inhabitants. Full article

Purpose: Neuroendocrine carcinomas (NECs) are aggressive tumors treated with cisplatin-based chemotherapy, though responses vary. As DNA damage response (DDR) pathways influence cisplatin sensitivity, this single-center retrospective study evaluates the efficacy of first-line cisplatin in recurrent or metastatic NEC based on DDR mutation status. Materials and Methods: This study analyzed patients with grade 3 recurrent or metastatic NEC treated with first-line etoposide plus cisplatin at Samsung Medical Center between January 2019 and September 2023. All patients underwent next-generation sequencing to determine DDR mutation status, defined by pathogenic alterations in major DNA repair pathways. Clinical outcomes were assessed per RECIST v1.1. Survival analyses were conducted using Kaplan–Meier methods and Cox regression models, with significance set at p ≤ 0.05. Results: A total of 40 patients with NEC were included in this study. There were 16 patients with DDR wild-type (WT) and 24 patients with DDR mutant type (MT). The most common primary tumor sites were the pancreas (25.0%), stomach (20.0%), and gallbladder/duct (12.5%). Among 40 patients, those with DDR mutations (n = 24) showed significantly higher objective response (58.3% vs. 12.5%) and disease control rates (91.7% vs. 50.0%) compared to patients with DDR WT (n = 16). The median progression-free survival (PFS) showed the favorable trend in the DDR mutant group (8.0 vs. 4.3 months; p = 0.15), with similar trends observed across homologous recombination repair (HRR), Fanconi anemia (FA), and mismatch repair (MMR) subgroups. Conclusions: This study revealed that patients with DDR mutations had significantly higher response to first-line etoposide–cisplatin, suggesting DDR mutation status as a potential predictive marker to guide treatment and improve outcomes in recurrent or metastatic NEC. Full article

Background: Lynch syndrome (LS) is an autosomal dominant disease caused by germline pathogenic variants in one of the DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6, and PMS2) or the EPCAM gene. LS patients harboring genetic variants in one of the MMR genes display a heterogeneous phenotype in terms of cancer penetrance (lifetime cancer risk) and expressivity (malignancies in gastrointestinal or other specific organs). Methods: DNA samples from the index cases of Family 1 and Family 2 were analyzed using a next-generation sequencing (NGS) multigene panel comprising 25 genes involved in major hereditary cancer predisposition syndromes. This NGS analysis revealed a variant of uncertain significance (VUS) in the PMS2 gene (NM_000535.7: c.184G>A; p.Gly62Arg) of both index cases, which was validated by Sanger sequencing. The structural and functional impact of this VUS was evaluated in silico using twelve different prediction tools and by immunohistochemical analysis of MMR proteins. Results: Based on the personal and family history of the two families, tumor pathology, and protein in silico analysis, the novel PMS2 gene variant described in this study may be associated with hereditary LS. Considering the low penetrance of PMS2 gene variants in LS-associated tumors and the intrafamilial variability of the associated clinical phenotypes, the multidisciplinary approach proposed in this study could significantly support the evaluation of suspected LS cases carrying PMS2 variants. Full article

Background: This study is the first to investigate the association between colorectal cancer (CRC) risk and the hMLH1 −93G>A and hMSH2 1032G>A polymorphisms of mismatch repair (MMR) genes in the Azerbaijani population. Methods: Peripheral blood samples containing EDTA were collected from the study subjects (134 patients and 137 controls), and genomic DNA was extracted using the non-enzymatic salting-out method. Genotypes were determined by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP), and the results were visualized through agarose gel electrophoresis. Results: Overall, no statistically significant correlation was observed between CRC risk and the hMLH1 −93G>A polymorphism in the heterozygous GA (OR = 0.760; 95% CI = 0.374–1.542; p = 0.446), the mutant AA (OR = 1.474; 95% CI = 0.738–2.945; p = 0.270), or the A allele (OR = 1.400; 95% CI = 0.984–1.995; p = 0.062). However, in contrast to the dominant model, a statistically significant association was found between the recessive model and an increased CRC risk, with an odds ratio of 1.788 (95% CI = 1.102–2.900; p = 0.018). The hMLH1 −93G>A polymorphism was identified at a significantly higher frequency across the TNM stages, with the distribution showing statistical significance (p < 0.05). Additionally, no statistically significant association was observed between the hMSH2 1032G>A polymorphism and CRC risk. Conclusions: Although no overall association was observed for hMLH1 −93G>A, our findings suggest a potential link with increased colorectal cancer risk under the recessive model in the Azerbaijani population. Further studies are warranted to confirm this model-specific association and investigate the underlying biological mechanisms. Full article

The DNA mismatch repair (MMR) system plays a crucial role in repairing DNA damage and regulating cell cycle arrest induced by cadmium (Cd) stress. To elucidate the mechanism by which miRNAs target AtMSH2 in regulating Arabidopsis’ response to Cd stress, the wild-type Arabidopsis, Atmsh2 mutant, and three miRNA-overexpressing transgenic lines were grown hydroponically in half-strength MS solution containing cadmium (Cd) at concentrations of 0, 0.5, 1, 2, and 3 mg/L for 5 days. miRNA-seq analysis, bioinformatics prediction, dual-luciferase reporter assays, and qRT-PCR results demonstrated that miR5651, miR170-3p, and miR171a-3p specifically targeted AtMSH2 and their expression levels showed a significant negative correlation. Compared to wild-type (WT) Arabidopsis, Cd stress tolerance was significantly enhanced in miRNA-overexpressing transgenic lines. Moreover, exogenous application of these three miRNAs in half-strength MS liquid medium also markedly improved Cd stress tolerance in wild-type Arabidopsis. Furthermore, the expression of these three miRNAs expression was further upregulated by Cd stress in a dose-dependent manner. Additionally, DNA damage response in miRNA-overexpressing transgenic lines was promoted based on the expression of DNA repair, DNA damage signaling, and cell cycle genes, which differed from both wild-type and Atmsh2 plants. Taken together, miR5651, miR170-3p, and miR171a-3p participated in Cd stress response and improved plant Cd tolerance by mediating the expression of AtMSH2. Our study provides novel insights into the epigenetic mechanisms of Cd tolerance in plants, which sheds light on breeding for stress resilience in phytoremediation. Full article

Sarcomyxa edulis is a characteristic low-temperature, edible mushroom in Northeast China. It has a delicious taste and rich nutritional and medicinal value. S. edulis can undergo explosive fruiting, neat fruiting, and unified harvesting, making it suitable for factory production. The molecular mechanisms underlying fruiting body development in S. edulis remain poorly understood. This study employed transcriptome analysis to compare the post-ripening mycelium (NPM) and primordial fruiting bodies (PRMs) of the thermostable S. edulis strain PQ650759, which uniquely forms primordia under constant temperature. A total of 4862 differentially expressed genes (DEGs) (|log2(fold change)| ≥ 1) were identified and found to be predominantly enriched in biological processes such as cell wall organization, DNA replication, and carbohydrate metabolism. KEGG pathway analysis revealed significant enrichment in 20 metabolic pathways, including mismatch repair, yeast cell cycle, and starch/sucrose metabolism. Ten candidate genes (e.g., SKP1, MRE11, GPI) linked to cell cycle regulation, DNA repair, and energy metabolism were randomly selected and prioritized for functional analysis. Quantitative PCR validation confirmed the reliability of transcriptome data, with expression trends consistent across both methods. Our findings provide critical insights into the molecular regulation of fruiting body development in S. edulis and establish a foundation for future mechanistic studies and strain optimization in industrial cultivation. Full article

Locally advanced rectal cancer treatment has shifted toward personalized, risk-adapted strategies that balance oncologic control with functional preservation while minimizing toxicity. A multidisciplinary team approach is essential, tailoring treatment guided by individual patient risk factors and priorities. Traditional neoadjuvant chemoradiation and subsequent total mesorectal excision has improved local control, but concerns remain regarding systemic failure and treatment-related morbidity. Total neoadjuvant therapy is now widely considered a preferred approach for more advanced tumors, enhancing systemic control, improving chemotherapy compliance, and facilitating organ preservation in select patients. Recent studies highlight that response-based treatment adaptation allows for better patient stratification, with selected patients who respond well to preoperative chemotherapy potentially omitting radiation without compromising outcomes and omitting surgery for patients with complete clinical responses to chemoradiation and chemotherapy. Advances in molecular profiling, particularly in mismatch repair deficiency or microsatellite instability-high tumors, have enabled the implementation of immune checkpoint inhibitors, permitting select patients to avoid both radiation and surgery, thereby reducing treatment-related toxicities. Future research should focus on validating predictive biomarkers, such as circulating tumor DNA, refining patient selection, and optimizing treatment monitoring while also developing novel therapeutic strategies to further personalize locally advanced rectal cancer management. Full article

Methods: We retrospectively and cross-sectionally reviewed the cases of 648 patients with a histological diagnosis of colon adenocarcinoma. Of these, 166 had partial molecular studies, and 42 cases were selected based on the availability of the genetic markers targeted in this study. We analyzed the frequency of mutations in these genes, as well as their correlation with microsatellite instability (MSI). Results: A high mutation rate was found in the KRAS gene (52.4%). NRAS mutations were less frequent (8.9%), whereas BRAF mutations were observed in 20.8% of cases. This allowed us to identify a patient subgroup with MSI, representing 12.1% of cases. Among the 42 patients analyzed for KRAS, NRAS, BRAF, and MSI mutations, a significant association was observed between KRAS mutations and microsatellite stability, while no association was found between NRAS mutations and MSI. BRAF mutations showed a statistically significant association with MSI (p < 0.05), with the most common mutation being c.1799T > A, p.Val600Glu. The objective of this study is to demonstrate that the NGS-based method for evaluating MSI is rigorously valid compared to the results obtained using IHC and PCR. Conclusions: Comprehensive NGS profiling from the start improves diagnostic efficiency by saving time, tissue, and costs compared to gene-by-gene analysis. It also enables better molecular characterization and facilitates tailored therapeutic strategies, particularly in identifying candidates for targeted therapy and immunotherapy. This approach supports efficient tumor classification based on using KRAS, BRAF, NTRK, ERBB2, and PIK3CA as key markers, along with MSI status. We recommend that, if initial NGS is not feasible, start with KRAS analysis, then test BRAF and MSI if no mutation is found. Full article

Colorectal cancer (CRC) remains a major health burden in Japan, with precision medicine playing an increasingly critical role in treatment optimization. Key biomarkers, including RAS, BRAF, microsatellite instability/mismatch repair, and human epidermal growth factor receptor 2, can be used as a guide for molecularly targeted therapies and immunotherapy. Advances in molecular diagnostics, including comprehensive genomic profiling, have enabled more precise treatment selection such as RET and NTRK fusions. Nationwide initiatives, such as c-CAT and SCRUM-Japan, can leverage real-world data to refine clinical strategies. Recent developments in circulating tumor DNA analysis have led to novel approaches for minimal residual disease monitoring, as demonstrated by the CIRCULATE-Japan GALAXY study. However, certain challenges persist, including the time required for genetic testing, the limited availability of targeted therapies, and disparities in access to molecular tumor boards. This review summarizes the current landscape of precision medicine in CRC in Japan, emphasizing key biomarkers, genetic testing strategies, targeted therapies, and emerging technologies. Future research should focus on expanding clinical trial access, accelerating drug approvals, and integrating real-world data into clinical practice to further advance precision medicine. Full article

Colorectal cancer (CRC) is the third most common cancer in the world, with increasing incidence and mortality rates. Standard conventional treatments for CRC are surgery, chemotherapy, and radiotherapy. Recently, immunotherapy has been introduced as a promising alternative to CRC treatment that utilizes patients’ immune system to combat cancer cells. The beneficial effect of immune checkpoint inhibitors, specifically anti-PD-1/ PD-L1, has been ascribed to the abundance of DNA replication errors that result in the formation of neoantigens. Such neoantigens serve as distinct flags that amplify the immune response when checkpoint inhibitors (ICIs) are administered. DNA replication errors in CRC patients are expressed as two statuses: the first is the deficient mismatch repair (MSI-H/dMMR) with a higher overall immune response and survival rate than the second status of patients with proficient mismatch repair (MSS/pMMR). There is a limitation to using anti-PD-1/PD-L1 as it is only confined to MSI-H/dMMR, where there is an abundance of T-cell inhibitory ligands (PD-L1). This calls for investigating new therapeutic interventions to widen the scope of ICIs’ role in the treatment of CRC. Autophagy modulation provides a good example. Autophagy is a cellular process that plays a crucial role in maintaining cellular homeostasis and has been studied for its impact on tumor development, progression, and response to treatment. In this review, we aim to highlight autophagy as a potential determinant in tumor immune response and to study the impact of autophagy on the tumor immune microenvironment. Moreover, we aim to investigate the value of a combination of anti-PD-1/PD-L1 agents with autophagy modulators as an adjuvant therapeutic approach for CRC treatment. Full article

Background: Defective DNA repair systems result in the accumulation of mutations, loss of genomic integrity, and eventually cancer. Following initial malignant transformation due to specific DNA damage and defective DNA repair, cancer cells become reliant upon other DNA repair pathways for their survival. The co-occurrence of specific repair deficiencies brings catastrophic outcomes such as cell death for cancer cells and thus holds promise as a potential therapeutic strategy. Exploring the co-occurrence and mutual exclusivity of mutational signatures provides valuable knowledge regarding combinations of defective repair pathways that are cooperative and confer selective advantage to cancer cells and those that are detrimental and cannot be tolerated by them. Methods: Taking advantage of mutational signature profiling, we analyzed whole-genome sequences of 1014 breast cancers to reveal the underlying mutational processes and their interrelationships. Results: We found an inverse relationship between deficiencies of homologous recombination (HRd) and non-homologous end joining (NHEJd) with reactive oxygen species (ROS). Moreover, HRd and NHEJd co-occurred with APOBEC but were mutually exclusive with mismatch repair deficiency (MMRd) and ROS. Our analysis revealed that SBS8 and SBS39 signatures of currently unknown etiology correlate with NHEJd. ID1 and ID2 signatures co-occur with ROS and have mutual exclusivity with HRd, SBS8, SBS39 and NHEJd. The ID4 signature, with currently unknown etiology, has mutual exclusivity with HRd and NHEJd and co-occurred with ROS. On the other hand, the ID15 signature, with currently unknown etiology, co-occurred with SBS8, SBS39, HRd, NHEJd and DBS2, while having an inverse relationship with MMRd and ROS. Comparing the mutational signatures of HRd and non-HRd TNBC genomes reveals the unique presence of ROS signatures in non-HRd tumors and the lack of ROS signature in HRd tumors. Conclusion: Taken together, these analyses indicate the possible application of mutation signatures and their interactions in advancing patient stratification and suggest appropriate therapies targeting the make-up of individual tumors’ mutational processes. Ultimately, this information provides the opportunity to discover promising synthetic lethal candidates targeting DNA repair systems. Full article