DNA repair, genome stability and cancer: a historical perspective

Versatile and programmable dual-mode logic gold nanoflares for intracellular correlated DNA repair enzymes imaging

In situ monitoring of correlated DNA repair enzyme activities in living cells is crucial for clinical and biomedical research. Here, we introduce a versatile, programmable dual-mode logic gold nanoflares strategy for OR/AND gate logic imaging the activity of apurinic/apyrimidinic endonuclease 1 (APE1) and flap endonuclease 1 (FEN1) within cells. The logic gold nanoflares were designed via conjugating enzyme-activatable sites modified branched double-stranded DNA structures to gold nanoparticles. These meticulously engineered nanoflares specifically respond to APE1 and FEN1 in living cells through logic biocomputing, emitting a fluorescent signal that allows for the sensitive monitor of APE1 and FEN1 activities. In vitro experiments demonstrate that the nanoflares are highly biocompatible and can make effectively and sensitively judgments on the two enzyme targets across various cancer cell lines. This OR/AND dual-mode logic gold nanoflare strategy offers a straightforward tool for the comprehensive analysis of multiple DNA repair enzymes, presenting promising applications in disease diagnosis, drug efficacy evaluation, and programmable therapeutics.

A novel high-throughput single-molecule technique DNA curtain: applications for DNA metabolism

The advancement of single-molecule imaging techniques has significantly enhanced our understanding of biomolecular reactions and cellular processes that remain obscured in ensemble measurements. In particular, DNA curtains are high-throughput hybrid methods integrating total internal reflection fluorescence microscopy, lipid fluidity, microfluidics, and nano-fabrication, enabling the direct visualization of protein-DNA interactions in real time. The techniques have emerged as powerful tools for probing molecular dynamics of diverse DNA metabolic processes, including DNA damage repair and chromatin dynamics. This review not only highlights recent applications of DNA curtain techniques for elucidating mechanisms underlying DNA damage repair and chromatin dynamics, but also shows how DNA curtain techniques have provided novel insights into the interplay between DNA metabolic processes in the chromatin context.

Multi-Omics Pan-Cancer Profiling of HSD17B10 Unveils Its Prognostic Potential, Metabolic Regulation, and Immune Microenvironment Interactions

This study systematically analyzed the expression and clinical significance of Hydroxysteroid 17-beta dehydrogenase type 10 (HSD17B10) in 33 cancers by integrating TCGA, GTEx, and other multi-omics databases. HSD17B10 was highly expressed in 14 cancers, like GBM and LGG, but low in 5, such as KIRC. Its expression correlated closely with overall survival (OS) and disease-free survival (DFS). In GBM-LGG, LGG, and other cancers, high HSD17B10 expression was linked to lower survival rates, indicating that it could be an independent prognostic marker. HSD17B10 also had a two-way relationship with the tumor's immune microenvironment. In cancers such as GBM-LGG, high expression correlated positively with immune/stromal scores. However, in most cancers like LUAD, it was negatively associated with B- and T-cell infiltration. Epigenetic analysis showed that low methylation in the HSD17B10 promoter region might drive its high expression in tumors such as SARC, and specific methylation sites (e.g., CG26323797) were significantly related to patient survival. Functional enrichment analysis revealed that HSD17B10 participated in tumor progression by regulating oxidative phosphorylation, mitochondrial metabolism, and RNA methylation. Single-cell and spatial transcriptome data further demonstrated that HSD17B10 had a cell-type-specific expression pattern in colorectal cancer. This study provides a theoretical basis for HSD17B10 as a pan-cancer prognostic marker and therapeutic target.

ANP32E drives vulnerability to ATR inhibitors by inducing R-loops-dependent transcription replication conflicts in triple negative breast cancer

Oncogene-induced replicative stress (RS) drives tumor progression by disrupting genome stability, primarily through transcription-replication conflicts (TRCs), which promote R-loop accumulation and trigger the DNA damage response (DDR). In this study, we investigate the role of chromatin regulators in exacerbating TRCs and R-loop accumulation in cancer. We find that in breast cancer patients, the simultaneous upregulation of MYC and the H2A.Z-specific chaperone ANP32E correlates with increased genomic instability. Genome-wide analyses reveal that ANP32E-driven H2A.Z turnover alters RNA polymerase II processivity, leading to the accumulation of long R-loops at TRC sites. Furthermore, we show that ANP32E overexpression enhances TRC formation and activates an ATR-dependent DDR, predisposing cancer cells to R-loop-mediated genomic fragility. By exploiting the vulnerability of ANP32E-expressing cancer cells to ATR inhibitors, we find that tumors relied on this DDR pathway, whose inhibition halts their pro-metastatic capacity. These findings identify ANP32E as a key driver of TRC-induced genomic instability, indicating ATR inhibition as a potential therapeutic strategy for ANP32E-overexpressing tumors.

Suppressed DNA repair capacity in flight attendants after air travel

Elevated cancer risk and compromised reproductive health have been well documented in flight attendants (FA), but the etiology remains unknown. Many studies using cell and animal models suggest that air travel related exposures might plausibly explain the adverse health outcomes observed in flight crew, but our understanding of the underlying biological mechanisms is incomplete. During air travel, FA are constantly exposed to complex mixtures of mutagens in the flight cabin that may contribute to genomic instability by inducing DNA damage and interfering with DNA repair. Defects in DNA repair capacity (DRC) have been associated with risk of cancer and other diseases. To explore our hypothesis that alterations in DNA damage and repair in FA are related to flight travel, we conducted a pilot study of FA's DNA damage and assess global DNA repair efficiency pre and post flight. We collected venous blood samples from nine FA before and after flight. Differential blood cell counts were carried out to assess immune responses and functional assays were performed to assess the DNA damage response. The CometChip assay was employed to quantify baseline DNA damage and repair kinetics for DNA damage induced by X-rays. Fluorescence multiplex based host cell reactivation (FM-HCR) assays were utilized to assess DRC in five major DNA repair pathways. Our findings revealed a significant increase in lymphocyte counts as well as diminished repair of ionizing radiation induced DNA damage and excision of 8oxoG:C lesions in after flight samples. Our results illustrate the potential for using biological samples to identify molecular mechanisms that may implicate impaired genomic stability and altered immune responses in the etiology of excess cancer in FAs.

DNA damage repair-related methylated genes RRM2 and GAPDH are prognostic biomarkers associated with immunotherapy for lung adenocarcinoma

Research has highlighted the significant role of methylated genes associated with DNA damage repair in pathogenesis of Lung adenocarcinoma (LUAD). However, the potential of DNA damage repair-related gene (DDRG) methylation as a prognostic biomarker remains underexplored. This study aimed to assess the prognostic value of methylated DDRGs in LUAD. Analysis of the TCGA-LUAD dataset revealed differentially expressed genes (DEGs) and differentially methylated genes (DE-MGs), from which methylated DE-DDRGs were identified. An independent prognostic risk model was constructed based on these methylated DE-DDRGs by integrating risk scores with clinical features. Additionally, the study examined responses to immunotherapy. Results indicated that CLU exhibited hypermethylation and elevated expression in LUAD tissues, while eight other genes (BUB1B, SHCBP1, RRM2, RPL39L, TRIP13, GAPDH, ENO1, and CENPM) showed high expression and hypomethylation. Among these, RRM2 and GAPDH were significantly linked to poorer overall survival. Furthermore, single-sample gene set enrichment analysis (ssGSEA) revealed that patients with LUAD in the high-risk group had lower immune scores and less immune cell infiltration. TIDE analysis suggested that patients in the low-risk group may exhibit greater sensitivity to immune checkpoint inhibitor therapy. In conclusion, RRM2 and GAPDH represent promising prognostic and immunotherapeutic biomarkers, offering new avenues for LUAD treatment strategies.

Role of HSP40 proteins in genome maintenance, insulin signaling and cancer therapy

The DnaJ heat shock protein family (HSP40) is the biggest chaperone family in mammalian cells, mainly functioning as cochaperone of HSP70 to maintain proteostasis and cellular homeostasis under both normal and stressful conditions. Although the functions of HSP70s have been extensively studied in diverse biological pathways and senesces including genome maintenance, HSP40s' biological functions at basal state or in response to exogenous insults remain largely under-investigated. Emerging evidence shows that HSP40 proteins participate in genome maintenance pathways and modulate cancer therapy efficacy. This review aims to summarize recent progresses regarding HSP40's functions in genome maintenance and cancer therapy, and provides hints for future studies in the field.

Solid pancancer analysis reveals immune and hematopoietic stem cell and DNA damage repair signatures to distinguish different cancer subtypes

PURPOSE

Immunity, stemness, and DNA damage repair (DDR) are crucial for cancer development and therapy resistance. With advancements in multiomics technology, the exploration of cancers related to immunity, stemness, and the DDR has triggered interest, but the combination of these levels for analyzing multiple cancers remains insufficient.

METHODS

In this study, 9906 solid tumor samples from 31 TCGA cancer types were clustered on the basis of the enrichment levels of 13 gene sets associated with stemness, immunity, and DDR. Moreover, a soft ensemble model was constructed on the basis of the enrichment levels of these 13 gene sets to predict cancer subtypes via other omics data.

RESULTS

We identified four pancancer subtypes, termed C1, C2, C3, and C4, which presented distinct molecular and clinical features, including the immune microenvironment, stemness, genome instability, intratumor heterogeneity, methylation levels, tumor progression, sensitivity to chemotherapy and immunotherapy, and survival prognosis. The soft ensemble model validated this subtyping method in two breast cancer datasets (gene expression level), a pancancer proteomic dataset (protein expression level), and a pancancer cell line dataset (cell line gene expression level).

CONCLUSION

Our findings indicate that immune, stemness, and DDR signature-based subtyping offers new perspectives on cancer biology and holds promise for improving the clinical management of cancers.

Identification of DNA damage and repair gene-related markers in pancreatic ductal adenocarcinoma by single-cell and bulk RNA sequencing

BACKGROUND

The DNA damage response (DDR) has a major impact on the development and progression of pancreatic ductal adenocarcinoma (PDAC). Investigating biomarkers linked to the DDR may facilitate prognostic assessment and prediction of immunological characteristics for patients with PDAC.

METHODS

The single-cell RNA sequencing (scRNA-seq) dataset GSE212966 was obtained from the GEO database, whereas the bulk RNA-seq data were sourced from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases. Least absolute shrinkage and selection operator (LASSO) and univariate Cox regression analyses were used to select genes to construct a prognostic risk model. Finally, the correlations of the model score with drug sensitivity, immunological checkpoints, and immune infiltration were assessed.

RESULTS

We used 16 DDR marker genes to construct a predictive model. Furthermore, we established that the model had strong performance in both the training and validation cohorts. For PDAC, the model risk score served as an independent predictor of prognosis. There were notable differences in the proportions of the immune cells in the tumor microenvironment and drug sensitivity between the high and low risk score groups. The study confirmed that the risk score model is useful for predicting the immunotherapy response. Our experiments verified that knockdown of LY6D inhibits cell proliferation, promotes apoptosis and DNA damage.

CONCLUSION

Our creative integration of bulk RNA sequencing and scRNA-seq data allowed us to construct a DDR-related prognostic model. Our model can be used to predict the immunological features, treatment response and prognosis of PDAC with a relatively high degree of accuracy.

Comprehensive Genetic Profile of Chinese Muscle-Invasive Bladder Cancer Cohort

OBJECTIVE

The aim of our study was to characterize the spectrum of mutations in muscle-invasive bladder cancer (MIBC) in the Chinese population, identifying mutational features and exploring potential therapeutic targets.

METHODS

We collected samples from 62 Chinese patients with MIBC. For each patient, tumor tissues or blood samples were collected and sequenced by whole exome sequencing.

RESULTS

Our findings revealed the most frequently mutated genes included TP53 (41%), TTN (41%), HYDIN (34%), FRG1 (33%), ZNF717 (23%), AHNAK2 (21%), MUC4 (21%), KMT2D (20%), CDC27 (18%) and IGSF3 (18%). The most frequently mutated DNA damage repair (DDR) genes were TP53 (49%), SMARCA4 (10%), ERCC2 (8%), BRAC2 (6%), HERC2 (6%), HLTF (6%), PALB2 (6%) and POLG (6%). Additionally, our analysis confirmed an association between DDR mutations and high TMB (P = .022). Significant differences in MSI were observed between smokers and nonsmokers (P = .022), drinkers and nondrinkers (P = .018). By analyzing the data of 323 white MIBC samples from TCGA database, we identified frequently mutated driver genes in both our cohort and TCGA white cohort, including TP53, KMT2D, KMT2C, and FGFR3. Our study also revealed genes with distinct mutation frequencies compared to the TCGA white cohort, including FRG1, CDC27, IGSF3, MUC16, and ARID1A.

CONCLUSIONS

Our study provided comprehensive insights into genomic alterations in a cohort of Chinese MIBC, which could provide potential clues for clinical applications.

p53 activates circASCC3 to repress R-loops and enhance resistance to chemotherapy

The tumor suppressor p53 can trigger tumor resistance to chemotherapy by facilitating DNA damage repair and maintaining genomic integrity. Here, we report that a p53-induced circular RNA circASCC3 promotes chemotherapeutic resistance by resolving R-loops. Our results reveal that p53 directly activates the transcription of ASCC3, the host gene of circASCC3. In addition, the RNA-binding protein SFPQ is identified to inhibit the formation of circASCC3 by associating with its flanking regions. Importantly, p53 facilitates the formation of circASCC3 by repressing the expression of SFPQ. CircASCC3 has a marginal effect on the survival and growth of cancer cells under normal growing conditions but surprisingly boosts their survival and growth in response to DNA damage stress. Mechanistic analysis reveals that circASCC3 binds to the DEAD-box RNA helicase DDX5 to inhibit its proteasomal degradation. This results in the prevention of R-loop accumulation due to DNA damage, thereby conferring tumor resistance to chemotherapy. Together, our study uncovers that p53 activates circASCC3 to promote R-loop resolution, which maintains genomic stability and potentially contributes to chemoresistance.

hnRNPA2B1 deacetylation by SIRT6 restrains local transcription and safeguards genome stability

Repair of double strand breaks (DSBs) by RNA-binding proteins (RBPs) is vital for ensuring genome integrity. DSB repair is accompanied by local transcriptional repression in the vicinity of transcriptionally active genes, but the mechanism by which RBPs regulate transcriptional regulation is unclear. Here, we demonstrated that RBP hnRNPA2B1 functions as a RNA polymerase-associated factor that stabilizes the transcription complex under physiological conditions. Following a DSB, hnRNPA2B1 is released from damaged chromatin, reducing the efficiency of RNAPII complex assembly, leading to local transcriptional repression. Mechanistically, SIRT6 deacetylates hnRNPA2B1 at K113/173 residues, enforcing its rapid detachment from DSBs. This process disrupts the integrity of the RNAPII complex on active chromatin, which is a pre-requisite for transient but complete repression of local transcription. Functionally, the overexpression of an acetylation mimic stabilizes the transcription complex and facilitates the functioning of the transcription machinery. hnRNPA2B1 acetylation status was negatively correlated with SIRT6 expression, and acetylation mimic enhanced radio-sensitivity in vivo. Our findings demonstrate that hnRNPA2B1 is crucial for transcriptional repression. We have uncovered the missing link between DSB repair and transcriptional regulation in genome stability maintenance, highlighting the potential of hnRNPA2B1 as a therapeutic target.

Why are RNA processing factors recruited to DNA double-strand breaks?

DNA double-strand break (DSB) induction leads to local transcriptional silencing at damage sites, raising the question: Why are RNA processing factors (RPFs), including splicing factors, rapidly recruited to these sites? Recent findings show that DSBs cluster in a chromatin compartment termed the 'D compartment', where DNA damage response (DDR) genes relocate and undergo transcriptional activation. Here, we propose two non-mutually exclusive models to elucidate the rationale behind the recruitment of RPFs to DSB sites. First, RPFs circulate through the D compartment to process transcripts of the relocated DDR genes. Second, the D compartment serves as a 'post-translational modifications (PTMs) hub', altering RPF activity and leading to the production of unique DNA damage-induced transcripts, which are essential for orchestrating the DDR.

Impact of a Cancer-Associated Mutation on Poly(ADP-ribose) Polymerase1 Inhibition

Poly(ADP-ribose) polymerase1 (PARP1) plays a vital role in DNA repair, and its inhibition in cancer cells may cause cell apoptosis. In this study, we investigated the effects of a PARP1 variant, V762A, which is strongly associated with several cancers in humans, on the inhibition of PARP1 by three FDA-approved inhibitors: niraparib, rucaparib, and talazoparib. Specifically, we compared the inhibition of the mutant to that of wild-type (WT) PARP1. Additionally, we investigated how the mutation influences the binding of these inhibitors to PARP1. Our work suggests that while mutant PARP1 exhibits only minor differences in residual fluctuations, backbone deviations, and residue motion correlations compared to the WT under niraparib and rucaparib inhibitions, it shows significant and distinct differences in these features when inhibited by talazoparib. Among the three inhibitions, talazoparib inhibition uniquely lowers the average residue fluctuations in the mutant than the WT including lower fluctuations of mutant's N- and C-terminal residues in the catalytic domain, conserved H-Y-E traid residues, and donor loop (D-loop) residues which are important for catalysis more effectively than other inhibitions. However, talazoparib also significantly enhances destabilizing interactions between the mutation site in the HD domain in the mutant than WT. Further, among the three inhibitions, talazoparib inhibition uniquely and significantly disrupts the functional fluctuations of terminal regions in the mutant, which are otherwise present in the WT. The mutation and inhibition do not significantly affect PARP1's essential dynamics. Lastly, these inhibitors bind to the V762A mutant more effectively than to the WT, with similar binding free energies between them.

UVC-Induced Oxidative Stress and DNA Damage Repair Status in Head and Neck Squamous Cell Carcinoma Patients with Different Responses to Nivolumab Therapy

Accumulation of evidence highlighted the crosstalk between DNA damage repair and the immune system. Herein, we tested the hypothesis that in head and neck squamous cell carcinoma (HNSCC), the DNA repair capacity of patients' PBMCs correlates with therapeutic response to immune checkpoint blockade. Following in vitro UVC irradiation, oxidative stress, apurinic/apyrimidinic (AP) lesions, endogenous/baseline DNA damage, and DNA damage repair efficiency were evaluated in three HNSCC (UM-SCC-11A, Cal-33, BB49) and two normal cell lines (RPMI-1788, 1BR-3h-T), as well as in peripheral blood mononuclear cells (PBMCs) from 15 healthy controls (HC) and 49 recurrent/metastatic HNSCC patients at baseline (8 responders, 41 non-responders to subsequent nivolumab therapy). HNSCC cell lines showed lower DNA repair efficiency, increased oxidative stress, and higher AP sites than normal ones (all p < 0.001). Moreover, patients' PBMCs exhibited increased endogenous/baseline DNA damage, decreased DNA repair capacity, augmented oxidative stress, and higher AP sites than PBMCs from HC (all p < 0.001). Importantly, PBMCs from responders to nivolumab therapy showed lower endogenous/baseline DNA damage, higher DNA repair capacities, decreased oxidative stress, and reduced AP sites than non-responders (all p < 0.05). Together, we demonstrated that oxidative stress status and DNA repair efficiency in PBMCs from HNSCC patients are correlated with the response to immune checkpoint blockade.

DPH2 is a biomarker associated with cell death, immunity and prognosis based on pan-cancer analysis

OBJECTIVE

DPH2, also known as DPH2L2, is one of two human genes similar to yeast dph2. One DPH2 variant has been linked to diphthamide syndrome, a disorder affecting ribosome function. While studies on DPH2 in a single cancer type have been documented, no comprehensive investigations of DPH2 across pan-cancer have been reported, its role in tumor pathogenesis and development remains unclear.

METHODS

The predictive significance and immune and biological roles of DPH2 in 33 different cancer types were investigated. We conducted a comprehensive analysis of DPH2 in pan-cancer using various bioinformatics tools, including expression, prognosis, its association with immune infiltration, cell death, methylation, and many other aspects. In addition, qRT-PCR and immunohistochemistry experiments confirmed DPH2 expression in prostate adenocarcinoma (PRAD) tissues, DPH2 biological function in PRAD was assessed using in vitro experiments, and used immunofluorescence to validate the proteins associated with DPH2.

RESULTS

The DPH2 expression was high in most tumors and showed significant correlations with OS and PFI. Our experimental findings confirmed that DPH2 is highly expressed in PRAD, while DPH2 knockdown inhibited prostate cancer cell proliferation, invasion, and migration. Furthermore, our data suggest that DPH2 may significantly influence immune cell infiltration. DPH2 was significantly correlated with cell death-related genes. DPH2 can influence cancer progression through changes in DNA methylation levels, or N6-methyladenosine site modification. GSEA and GSVA revealed that DPH2 levels were significantly associated with enrichment for oncogenic and immune-related pathways. Drug sensitivity analysis revealed that the elevated DPH2 expression is linked to development of resistance against numerous anticancer medications.

CONCLUSION

DPH2 has potential as a novel prognostic biomarker that may significantly impact tumor onset and progression. Consequently, DPH2 could serve as a target for new cancer treatments.

DNA damage response and repair gene mutations predict clinical outcomes in biliary tract cancer

BACKGROUND

This study aims to explore the genetic characteristics of biliary tract cancer (BTC), with a particular focus on the impact of DNA damage response and repair (DDR) genes on clinical outcomes.

METHODS

A total of 180 patients with BTC and next-generation sequencing data were retrospectively analyzed. Clinical outcomes were compared between DDR-positive and DDR-negative groups.

RESULTS

DDR mutations were found in 28.3% of patients, with ATM (7.8%), BAP1 (5.6%), and BRCA2 (3.3%) being the most common. DDR-positive patients receiving first-line platinum-based chemotherapy (n = 73) had a significantly higher objective response rate (50.0% vs. 14.9 %; p = .001), longer median progression-free survival (mPFS) (7.7 vs. 3.8 months; p = .001) and longer median overall survival (28.6 vs. 11.9 months; p < .001). Multivariate analysis confirmed that deleterious DDR gene mutations were independently associated with prolonged mPFS (hazard ratio [HR], 0.37; 95% CI, 0.20-0.67; p < .001) and median overall survival (mOS) (HR, 0.19; 95% CI, 0.08-0.46; p < .001). In 56 patients receiving immunotherapy combined with chemotherapy, DDR-positive patients had a significantly higher overall response rate (45% vs. 8.3%; p = .001), longer mPFS (7.7 vs. 3.8 months; p = .009), and longer mOS (12.7 vs. 8.8 months; p = .011). Multivariate analysis showed that the presence of deleterious DDR gene mutations was associated with significantly longer mPFS (HR, 0.34; 95% CI, 0.16-0.73); p = .005] and mOS (HR, 0.23; 95% CI, 0.08-0.62; p = .004).

CONCLUSION

Deleterious DDR gene mutations are associated with improved clinical outcomes in patients with BTC treated with platinum-based chemotherapy or immunotherapy combined with chemotherapy.

Mouse ZGRF1 helicase facilitates DNA repair and maintains efficient fertility

The recently characterised human ZGRF1 helicase promotes genomic stability by facilitating DNA interstrand crosslink repair. In its absence, human cells exhibit greater sensitivity towards anti-cancer drugs such as mitomycin C and camptothecin. Moreover, the downregulation of ZGRF1 expression is associated with increased survival in cancer patients. These attributes point to ZGRF1 as a potential anti-cancer drug target. Here, we investigated the role of ZGRF1 in tumorigenesis using the mouse model. We generated a ZGRF1 mutant mouse and find that it is viable and displays normal development. However, at a cellular level, mouse embryonic fibroblasts exhibit sensitivity to ICLs and show elevated levels of the DNA damage marker γH2AX. In the absence of ZGRF1, the rates of tumorigenesis and tumour-free survival in Eμ-Myc and Trp53 knockout mice remained largely unaffected. These findings suggest a potential role for ZGRF1 in the proliferation of specific cancer types, highlighting avenues for further research in other cancer models. Additionally, beyond its known function in DNA repair, our study also reveals that ZGRF1 promotes meiotic recombination and that its loss results in reduced fertility in mice manifested as a 30 % reduction in meiotic crossovers and a 15 % reduction in litter size.

Pan-Cancer Analysis of the Prognostic and Immunotherapeutic Value of PDGFB

Introduction

Cancer is a widespread epidemic that affects millions of individuals across the world. Identifying novel cancer targets is crucial to developing more effective cancer treatments. Platelet-derived growth factor-B (PDGFB) plays a critical role in various tumor processes, including angiogenesis and lymphatic metastasis. However, there is a lack of research on the role of PDGFB in these processes.

Methods

To address this issue, we conducted a comprehensive analysis utilizing multiple online databases to investigate the expression, prognostic, tumor stemness, and immunological effect of PDGFB. In addition, clinical samples were validated using immunohistochemistry.

Results

Our findings revealed that PDGFB was highly expressed in a diverse range of cancer types, and its expression and genetic modifications were significantly associated with clinical outcomes in certain tumors. In general, high expression of PDGFB in tumors is associated with poor prognosis. Surprisingly, PDGFB was found to be highly expressed in renal clear cell carcinoma but was associated with good prognosis. In contrast, PDGFB was low expressed in lung carcinoma, but its expression was found to improve patient survival. These findings demonstrate the complex role of PDGFB in different cancer types. The study also demonstrated that PDGFB was linked to RNA and DNA stemness in 15 and 36 tumor types, respectively, and had a positive association with tumor lymphocyte infiltration. Notably, PDGFB was found to be associated with immune modulators. PDGFB, which is involved in various immune responses, influences the malignant characteristics of various cancer types and controls immune cell infiltration. We confirmed that PDGFB positively correlated with CD8 and PDL1 expression in lower grade glioma.

Conclusion

This study concludes that PDGFB may serve as a potential prognostic marker and a potential targetable pathway in cancer immunotherapy. Overall, the study sheds new light on the role of PDGFB in cancer and highlights its potential clinical significance.

Enhanced pharmacological activities of AKR1C3-activated prodrug AST-3424 in cancer cells with defective DNA repair

AST-3424 is a novel and highly tumor-selective prodrug. AST-3424 is activated by AKR1C3 to release a toxic bis-alkylating moiety, AST 2660. In this study, we have investigated the essential role of DNA repair in AST-3424 mediated pharmacological activities in vitro and in vivo. We show here that AST-3424 is effective as a single therapeutic agent against cancer cells to induce cytotoxicity, DNA damage, apoptosis and cell cycle arrest at G2 phase in a dose- and AKR1C3-dependent manner in both p53-proficient H460 (RRID:CVCL_0459) and p53-deficient HT-29 cells (RRID:CVCL_0320). The combination of abrogators of G2 checkpoint with AST-3424 was only synergistic in HT-29 but not in H460 cells. The enhanced activity of AST-3424 in HT-29 cells was due to impaired DNA repair ability via the attenuation of cell cycle G2 arrest and reduced RAD51 expression. Furthermore, we utilized a BRCA2 deficient cell line and two PDX models with BRCA deleterious mutations to study the increased activity of AST-3424. The results showed that AST-3424 exhibited enhanced in vitro cytotoxicity and superior and durable in vivo anti-tumor effects in cells deficient of DNA repair protein BRCA2. In summary, we report here that when DNA repair capacity is reduced, the in vitro and in vivo activity of AST-3424 can be further enhanced, thus providing supporting evidence for the further evaluation of AST-3424 in the clinic.

The multifaceted roles of aldolase A in cancer: glycolysis, cytoskeleton, translation and beyond

Cancer, a complicated disease characterized by aberrant cellular metabolism, has emerged as a formidable global health challenge. Since the discovery of abnormal aldolase A (ALDOA) expression in liver cancer for the first time, its overexpression has been identified in numerous cancers, including colorectal cancer (CRC), breast cancer (BC), cervical adenocarcinoma (CAC), non-small cell lung cancer (NSCLC), gastric cancer (GC), hepatocellular carcinoma (HCC), pancreatic cancer adenocarcinoma (PDAC), and clear cell renal cell carcinoma (ccRCC). Moreover, ALDOA overexpression promotes cancer cell proliferation, invasion, migration, and drug resistance, and is closely related to poor prognosis of patients with cancer. Although originally discovered to promote cancer initiation and progression by accelerating glycolysis, recent studies have revealed its atypical roles in cancer, e.g., adjusting cytoskeleton, regulating mRNA translation, cell signaling pathways, and DNA repair. These aforementioned findings challenge our traditional understanding of ALDOA function and prompt deep exploration of its novel roles in tumor biology. The present review summarizes the latest insights into ALDOA as a potential cancer biomarker and therapeutic target.

The association of the chemotherapy response score and homologous recombination deficiency in patients undergoing interval tumor reductive surgery following neoadjuvant chemotherapy

OBJECTIVES

In patients undergoing interval tumor reductive surgery, a good response to neoadjuvant chemotherapy may limit available tumor for homologous recombination deficiency testing. The objective of this study was to assess whether the chemotherapy response score predicts homologous recombination status.

METHODS

We identified patients with advanced epithelial ovarian cancer (diagnosed January 2019 to 20 June 2023) who received neoadjuvant chemotherapy, underwent interval surgery, and for whom a chemotherapy response score was reported (1=no or minimal tumor response, 2=appreciable tumor response, 3=complete or near complete response with no residual tumor). Comparisons were made using ANOVAs or Kruskal-Wallis test for continuous variables and χ2 or Fisher's exact test for categorical variables.

RESULTS

The cohort consisted of 234 patients with advanced ovarian cancer who underwent interval surgery following neoadjuvant chemotherapy. Of those who underwent germline genetic testing, 22% (51/232) had a pathogenic BRCA1 or BRCA2 mutation and of those with tumors sent for testing, 65% were found to have homologous recombination deficiency (66/146). With increasing chemotherapy response scores, a higher likelihood of a complete gross resection was observed (50% (chemotherapy response score, CRS 1) vs 77% (CRS 2) vs 88% (CRS 3), p<0.001). On multivariable analysis, CRS 2 (adjusted odds ratio=3.28, 95% CI 1.12 to 9.60, p=0.03) and CRS 3 (5.83, 1.79 to 18.93, p=0.003) were independently associated with homologous recombination deficiency compared with CRS 1.

CONCLUSION

A positive response to chemotherapy at the time of interval tumor reductive surgery defined by the chemotherapy response score was associated with homologous recombination status and the likelihood of achieving a complete gross resection.

Mitochondrial DNA damage, repair, and replacement in cancer

Mitochondria are vital organelles with their own DNA (mtDNA). mtDNA is circular and composed of heavy and light chains that are structurally more accessible than nuclear DNA (nDNA). While nDNA is typically diploid, the number of mtDNA copies per cell is higher and varies considerably during development and between tissues. Compared with nDNA, mtDNA is more prone to damage that is positively linked to many diseases, including cancer. Similar to nDNA, mtDNA undergoes repair processes, although these mechanisms are less well understood. In this review, we discuss the various forms of mtDNA damage and repair and their association with cancer initiation and progression. We also propose horizontal mitochondrial transfer as a novel mechanism for replacing damaged mtDNA.

RAD51 Expression as a Biomarker to Predict Efficacy of Platinum-Based Chemotherapy and PD-L1 Blockade for Muscle-Invasive Bladder Cancer

RAD51, a key recombinase that catalyzes homologous recombination (HR), is commonly overexpressed in multiple cancers. It is curial for DNA damage repair (DDR) to maintain genomic integrity which could further determine the therapeutic response. Herein, we attempt to explore the clinical value of RAD51 in therapeutic guidance in muscle-invasive bladder cancer (MIBC). In this retrospective study, a total of 823 patients with MIBC were included. Zhongshan hospital (ZSHS) cohort (n=134) and The Cancer Genome Atlas-Bladder Cancer (TCGA-BLCA) cohort (n=391) were included for the investigation of chemotherapeutic response. The IMvigor210 cohort (n=298) was utilized to interrogate the predictive efficacy of RAD51 status to programmed cell death ligand-1 (PD-L1) blockade. In addition, the association of RAD51 with genomic instability and tumor immune contexture was investigated. Patients with RAD51 overexpression were more likely to benefit from both platinum-based chemotherapy and immunotherapy rather than RAD51-low patients. The TMB high PD-L1 high RAD51 high subgroup possessed the best clinical benefits from PD-L1 blockade. RAD51-high tumors featured by genomic instability were correlated to highly inflamed and immunogenic contexture with activated immunotherapeutic pathway in MIBC. RAD51 could serve as a prognosticator for treatment response to platinum-based chemotherapy and PD-L1 inhibitor in MIBC patients. Besides, it could also improve the predictive efficacy of TMB and PD-L1.

A comprehensively prognostic and immunological analysis of PARP11 in pan-cancer

Poly (ADP-ribose) polymerase family member 11 (PARP11) has important immune regulatory functions in viral infection and tumor immune response. Particularly, PARP11 showed protumor activities in multiple preclinical murine models. However, no systematic pan-cancer analysis has been conducted to explore PARP11 function. In this study, we used multiple databases to assess PARP11 expression, which is associated with clinical outcomes, immune checkpoint factors, prognostic significance, genomic characteristics, and immunological aspects. The analysis revealed varying expression levels of PARP11 across different cancer types and a significant correlation between its expression and immune cell infiltration. Insights from the CellMiner database suggest a strong link between PARP11 expression and sensitivity to anticancer drugs, highlighting its potential as a therapeutic target. Moreover, PARP11 expression correlates with patient survival during anti-PD1 and anti-CTLA4 treatments, suggesting that PARP11 would be a predictor of immune checkpoint inhibitor treatment. In summary, PARP11 would be a potential immunoregulatory target and a diagnosis and prognosis marker for certain types of cancers. The detailed mechanisms of PARP11 in tumor immune responses need to be further investigated.

Not only the top: Type I topoisomerases function in multiple tissues and organs development in plants

BACKGROUND

DNA topoisomerases (TOPs) are essential components in a diverse range of biological processes including DNA replication, transcription and genome integrity. Although the functions and mechanisms of TOPs, particularly type I TOP (TOP1s), have been extensively studied in bacteria, yeast and animals, researches on these proteins in plants have only recently commenced.

AIM OF REVIEW

In this review, the function and mechanism studies of TOP1s in plants and the structural biology of plant TOP1 are presented, providing readers with a comprehensive understanding of the current research status of this essential enzyme.The future research directions for exploring the working mechanism of plant TOP1s are also discussed.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Over the past decade, it has been discovered TOP1s play a vital role in multiphasic processes of plant development, such as maintaining meristem activity, gametogenesis, flowering time, gravitropic response and so on. Plant TOP1s affects gene transcription by modulating chromatin status, including chromatin accessibility, DNA/RNA structure, and nucleosome positioning. However, the function and mechanism of this vital enzyme is poorly summarized although it has been systematically summarized in other species. This review summarized the research progresses of plant TOP1s according to the diverse functions and working mechanism in different tissues.

Systematic identification of pathogenic variants of non-small cell lung cancer in the promoters of DNA-damage repair genes

BACKGROUND

Deficiency in DNA-damage repair (DDR) genes, often due to disruptive coding variants, is linked to higher cancer risk. Our previous study has revealed the association between rare loss-of-function variants in DDR genes and the risk of lung cancer. However, it is still challenging to study the predisposing role of rare regulatory variants of these genes.

METHODS

Based on whole-genome sequencing data from 2984 patients with non-small cell lung cancer (NSCLC) and 3020 controls, we performed massively parallel reporter assays on 1818 rare variants located in the promoters of DDR genes. Pathway- or gene-level burden analyses were performed using Firth's logistic regression or generalized linear model.

FINDINGS

We identified 750 rare functional regulatory variants (frVars) that showed allelic differences in transcriptional activity within the promoter regions of DDR genes. Interestingly, the burden of frVars was significantly elevated in cases (odds ratio [OR] = 1.17, p = 0.026), whereas the burden of variants prioritized solely based on bioinformatics annotation was comparable between cases and controls (OR = 1.04, p = 0.549). Among the frVars, 297 were down-regulated transcriptional activity (dr-frVars) and 453 were up-regulated transcriptional activity (ur-frVars); especially, dr-frVars (OR = 1.30, p = 0.008) rather than ur-frVars (OR = 1.06, p = 0.495) were significantly associated with risk of NSCLC. Individuals with NSCLC carried more dr-frVars from Fanconi anemia, homologous recombination, and nucleotide excision repair pathways. In addition, we identified seven genes (i.e., BRCA2, GTF2H1, DDB2, BLM, ALKBH2, APEX1, and RAD51B) with promoter dr-frVars that were associated with lung cancer susceptibility.

INTERPRETATION

Our findings indicate that functional promoter variants in DDR genes, in addition to protein-truncating variants, can be pathogenic and contribute to lung cancer susceptibility.

FUNDING

National Natural Science Foundation of China, Youth Foundation of Jiangsu Province, Research Unit of Prospective Cohort of Cardiovascular Diseases and Cancer of Chinese Academy of Medical Sciences, and Natural Science Foundation of Jiangsu Province.

Recent advances in reactive oxygen species (ROS)-responsive drug delivery systems for photodynamic therapy of cancer

Reactive oxygen species (ROS)-responsive drug delivery systems (DDSs) have garnered significant attention in cancer research because of their potential for precise spatiotemporal drug release tailored to high ROS levels within tumors. Despite the challenges posed by ROS distribution heterogeneity and endogenous supply constraints, this review highlights the strategic alliance of ROS-responsive DDSs with photodynamic therapy (PDT), enabling selective drug delivery and leveraging PDT-induced ROS for enhanced therapeutic efficacy. This review delves into the biological importance of ROS in cancer progression and treatment. We elucidate in detail the operational mechanisms of ROS-responsive linkers, including thioether, thioketal, selenide, diselencide, telluride and aryl boronic acids/esters, as well as the latest developments in ROS-responsive nanomedicines that integrate with PDT strategies. These insights are intended to inspire the design of innovative ROS-responsive nanocarriers for enhanced cancer PDT.

BRAF V600E-induced distinct DNA damage response defines the therapeutic potential of p53 activation for TP53 wild-type colorectal cancer

BRAF V600E, one of the most frequent mutations in the MAPK pathway, confers poor prognosis to colorectal cancers (CRCs), partly because of chemotherapeutic resistance. Oncogene-induced DNA damage responses (DDRs) that primarily activate p53 are important mechanistic barriers to the malignant transformation of cells; however, the mechanism underlying this impairment in cancer remains unknown. Here, we evaluated the responses of BRAFV600E-induced DDRs in two CRC cell lines, SW48 and LIM1215, both of which harbor wild-type TP53, KRAS, and BRAF. BRAFV600E transduction exhibited distinct phenotypes in these cells: SW48 cell proliferation markedly decreased, whereas that of LIM1215 increased. BRAFV600E expression induced the activation of oncogene-induced DDR signaling in SW48 cells, but not in LIM1215 cells, whereas chemotherapeutic agents similarly activated DDRs in both cell lines. Knockdown experiments revealed that these responses in SW48 cells were mediated by p53-p21 pathway activation. Comet assay (both alkaline and neutral) revealed that BRAFV600E increased single-strand breaks to the same extent in both cell lines; however, in the case of LIM1215 cells, it only facilitated double-strand breaks. Furthermore, the proliferation of LIM1215 cells, wherein no oncogene-induced DDRs occurred, was synergistically inhibited upon MDM2 inhibitor-mediated p53 activation combined with MEK inhibition. Taken together, these distinct DDR signaling responses highlight the novel characteristics of BRAFV600E-mutated CRC cells and define the therapeutic potential of p53 activation combined with MAPK inhibition against TP53 wild-type CRC harboring a BRAFV600E mutation.

Disruption of RNA Splicing Increases Vulnerability of Cells to DNA-PK Inhibitors

DNA-dependent protein kinase (DNA-PK) is a key effector of non-homologous end joining (NHEJ)-mediated double-strand break (DSB) repair. Since its identification, a substantial body of evidence has demonstrated that DNA-PK is frequently overexpressed in cancer, plays a critical role in tumor development and progression, and is associated with poor prognosis in cancer patients. Recent studies have also uncovered novel functions of DNA-PK, shifting the paradigm of the role of DNA-PK in oncogenesis and renewing interest in targeting DNA-PK for cancer therapy. To gain genetic insight into the cellular pathways requiring DNA-PK activity, we used a CRISPR/Cas9 screen to identify genes in which defects cause hypersensitivity to DNA-PK inhibitors. We identified over one hundred genes involved in DNA replication, cell cycle regulation, and RNA processing that promoted cell survival when DNA-PK kinase activity was suppressed. This gene set will be useful for characterizing novel biological processes that require DNA-PK activity and identifying predictive biomarkers of response to DNA-PK inhibition in the clinic. We also validated several genes from this set and reported previously undescribed genes that modulate the response to DNA-PK inhibitors. In particular, we found that compromising the mRNA splicing pathway led to marked hypersensitivity to DNA-PK inhibition, providing a possible rationale for the combined use of splicing inhibitors and DNA-PK inhibitors for cancer therapy.

Homologous recombination deficiency score is an independent prognostic factor in esophageal squamous cell carcinoma

Homologous recombination deficiency (HRD) represents an impairment in the homologous recombination repair (HRR) pathway, crucial for repairing DNA double-strand breaks and contributing to genomic instability in cancer. The HRD score may be a more reliable biomarker than HRR-related gene mutations for identifying patients sensitive to poly(ADP-ribose) polymerase inhibitors. Despite its relevance in various cancers, the HRD score remains underexplored in esophageal squamous cell carcinoma (ESCC). We retrospectively analyzed HRD scores in 96 ESCC patients, examining correlations with clinical characteristics and survival outcomes, and validated our findings using the TCGA dataset. Genomic sequencing utilized a custom superHRD next-generation sequencing panel, and HRD scores were calculated from 54,000 single-nucleotide polymorphisms using Kruskal-Wallis rank-sum tests and two cut-off points for analysis. Higher HRD scores correlated with advanced tumor stages, recurrence, and mutations in TP53 and ABCB1, while APC mutations were linked to lower HRD scores. Patients with high HRD scores had significantly shorter disease-free survival (p = 0.013) and a trend toward shorter overall survival (OS) (p = 0.005), particularly those not receiving adjuvant therapy. Conversely, HRD-high patients undergoing adjuvant therapy showed a trend toward longer OS (p = 0.015). Multivariate analysis identified HRD as an independent prognostic factor (hazard ratio = 2.814 for recurrence, p = 0.015). Validation with the TCGA dataset supported these findings. This study highlights the associations between HRD scores, clinical characteristics, and genomic mutations in ESCC, suggesting HRD as a potential prognostic biomarker. HRD assessment may aid in patient stratification and personalized treatment strategies, warranting further investigation to validate the therapeutic implications of HRD scores in ESCC.

Annual space weather fluctuations and telomere length dynamics in a longitudinal cohort of older men: the Normative Aging Study

BACKGROUND

Space weather has been associated with increased risk of cardiovascular diseases in space and flight crew. However, limited research has focused on the ground population, particularly among the elderly who are vulnerable to aging-related diseases.

OBJECTIVE

We evaluated the association between space weather alterations and biological aging using leukocyte telomere length as a biomarker in healthy elderly men.

METHODS

We used data from the Normative Aging Study, a longitudinal cohort of healthy elderly men in Massachusetts, USA. Leukocyte telomere length and health information were measured at in-person examinations approximately every three years, contributing to a total of 1,850 visits from 791 participants. Regional space weather information was collected daily, including cosmic ray-induced ionization, neutrons, sunspot number, interplanetary magnetic field, and Kp-index as our exposure of interest. We used mixed-effects models with a random intercept per individual to evaluate the associations between annual averages of space weather indicators and relative telomere length while accounting for participant demographics, environmental parameters, and secular trends.

RESULTS

The mean age at baseline was 72.36 years. A one-year increment in age is associated with a 1.21% reduction in leukocyte telomere length. In the fully adjusted model accounting for individual and environmental factors, an interquartile range (IQR) increase of annual cosmic ray induced ionization (110.0 ion pairs cm-3 sec-1) was associated with a 17.64% (95%CI: -27.73%, -7.55%) decrease in leukocyte telomere length, equivalent to 15-years age increment. Solar and geomagnetic activities were associated with increased leukocyte telomere length, but the association became absent after adjusting for cosmic ray indicators.

IMPACT

Galactic cosmic rays may accelerate the aging process in populations on the Earth, despite the protection by the Earth's atmosphere and magnetic field. This research enhances our understanding of how changes in space weather can impact health, highlights potential risks from space to Earth's inhabitants, and helps inform health strategies for vulnerable populations.

ATR promotes mTORC1 activity via de novo cholesterol synthesis

DNA damage and cellular metabolism exhibit a complex interplay characterized by bidirectional feedback mechanisms. Key mediators of the DNA damage response and cellular metabolic regulation include Ataxia Telangiectasia and Rad3-related protein (ATR) and the mechanistic Target of Rapamycin Complex 1 (mTORC1), respectively. Previous studies have established ATR as a regulatory upstream factor of mTORC1 during replication stress; however, the precise mechanisms by which mTORC1 is activated in this context remain poorly defined. Additionally, the activity of this signaling axis in unperturbed cells has not been extensively investigated. Here, we demonstrate that ATR promotes mTORC1 activity across various cellular models under basal conditions. This effect is particularly enhanced in cells following the loss of p16, which we have previously associated with hyperactivation of mTORC1 signaling and here found have increased ATR activity. Mechanistically, we found that ATR promotes de novo cholesterol synthesis and mTORC1 activation through the upregulation of lanosterol synthase (LSS), independently of both CHK1 and the TSC complex. Furthermore, the attenuation of mTORC1 activity resulting from ATR inhibition was rescued by supplementation with lanosterol or cholesterol in multiple cellular contexts. This restoration corresponded with enhanced localization of mTOR to the lysosome. Collectively, our findings demonstrate a novel connection linking ATR and mTORC1 signaling through the modulation of cholesterol metabolism.

Development of a prognostic model related to homologous recombination deficiency in glioma based on multiple machine learning

Background

Despite advances in neuro-oncology, treatments of glioma and tools for predicting the outcome of patients remain limited. The objective of this research is to construct a prognostic model for glioma using the Homologous Recombination Deficiency (HRD) score and validate its predictive capability for glioma.

Methods

We consolidated glioma datasets from TCGA, various cancer types for pan-cancer HRD analysis, and two additional glioma RNAseq datasets from GEO and CGGA databases. HRD scores, mutation data, and other genomic indices were calculated. Using machine learning algorithms, we identified signature genes and constructed an HRD-related prognostic risk model. The model's performance was validated across multiple cohorts. We also assessed immune infiltration and conducted molecular docking to identify potential therapeutic agents.

Results

Our analysis established a correlation between higher HRD scores and genomic instability in gliomas. The model, based on machine learning algorithms, identified seven key genes, significantly predicting patient prognosis. Moreover, the HRD score prognostic model surpassed other models in terms of prediction efficacy across different cancers. Differential immune cell infiltration patterns were observed between HRD risk groups, with potential implications for immunotherapy. Molecular docking highlighted several compounds, notably Panobinostat, as promising for high-risk patients.

Conclusions

The prognostic model based on the HRD score threshold and associated genes in glioma offers new insights into the genomic and immunological landscapes, potentially guiding therapeutic strategies. The differential immune profiles associated with HRD-risk groups could inform immunotherapeutic interventions, with our findings paving the way for personalized medicine in glioma treatment.

Combination of radiotherapy and immunotherapy in duality with the protumoral action of radiation

Radiotherapy is widely used to treat various cancers. Its combination with immune checkpoint inhibitors is intensively studied preclinically and clinically. Although the first results were very encouraging, the number of patients who respond positively remains low, and the therapeutic benefit is often temporary. This review summarizes how radiation can stimulate an antitumor immune response and its combination with immunotherapy based on inhibiting immune checkpoints. We will provide an overview of radiotherapy parameters that should be better controlled to avoid downregulating the antitumor immune response. The low response rate of combining radiotherapy and immunotherapy could, at least in part, be caused by the stimulation of cancer cell invasion and metastasis development that occur at similar doses and number of radiation fractions. To end on a positive note, we explore how a targeted inhibition of the inflammatory cytokines induced by radiation with a cyclooxygenase-2 inhibitor could both support an antitumor immune response and block radiation-induced metastasis formation.

UHRF1-mediated ubiquitination of nonhomologous end joining factor XLF promotes DNA repair in human tumor cells

UHRF1 (Ubiquitin-like with PHD and Ring Finger domains 1) is a crucial E3 ubiquitin ligase and epigenetic regulator with pivotal roles in various biological processes, including the maintenance of DNA methylation, regulation of gene expression, and facilitation of DNA damage repair. In this study, we unveil that UHRF1 interacts with the nonhomologous end joining factor XLF (also known as Cernunnos) following DNA double strand breaks in HeLa cells. Furthermore, we demonstrate that UHRF1 catalyzes lysine 63-linked polyubiquitination of XLF, rather than lysine 48-linked polyubiquitination. Notably, this polyubiquitination of XLF by UHRF1 does not affect its protein stability; instead, it enhances the recruitment of XLF to the sites of DNA damage. These findings shed light on the role of UHRF1 as a novel regulator of DNA repair through XLF in tumor cells.

Internal Overview of Prostatic Cancer Cases and Quality of BRCA1 and BRCA2 NGS Data from the FFPE Tissue

Background: Comprehensive genomic profiling (CGP) has gained an important role in patients with advanced prostate cancer following the introduction of PARP inhibitors in daily clinical practice. Here, we report an overview of CGP results, specifically of BRCA1 and BRCA2 HRD-repair system genes, from patients with prostate cancer analyzed in our institution, and we compare our results with those available from more recent scientific literature. Methods: The study cohort consisted of 70 patients. Somatic DNA was extracted from Formalin-Fixed Paraffin-Embedded (FFPE) tissue using a MagCore Genomic DNA FFPE One-Step Kit for MagCore System. The DNA was quantified by EasyPGX® Real-Time qPCR and EasyPGX® Analysis Software (version 4.0.13). Tissue somatic DNA libraries were prepared with Myriapod® NGS BRCA1-2 panel-NG035 and sequenced in a Mi-Seq® System. The sequence alignment in hg19 and the variant calling were performed using Myriapod® NGS Data Analysis Software version 5.0.8 NG900-SW 5.0.8 with a software detection limit (LoD) of 95%. Variants with a coverage of 500 and VAF% ≥ 5 were evaluated. Results: Tumor tissue NGS was unsuccessful in 46/70 patients (66%). Mutations of the BRCA2 gene were detected in 4 of the samples: (1) BRCA2 ex10 c.1244A>G p.His415Arg VAF = 51.03%; (2) BRCA2 ex11 c.5946delT p.Ser1982fs VAF = 72.1%; (3) BRCA2 ex11 c.3302A>G p.His1101Arg VAF = 52.9%; and (4) BRCA2 ex11 c.3195_3198delTAAT p.Asn1066fs VAF = 51.1%. Conclusions: The results from our internal overview seem to support the data and to confirm the performance of the technical issues reported in the literature. Considering the advanced age of our patients, with 84% of men over the age of 65, the application of alternative and less invasive procedures such as liquid biopsy, could be a more suitable solution for some cases.

Identification of two heterogeneous subtypes of hepatocellular carcinoma with distinct pathway activities and clinical outcomes based on gene set variation analysis

Background

High heterogeneity is an essential feature of malignant tumors. This study aims to reveal the drivers of hepatocellular carcinoma heterogeneity for prognostic stratification and to guide individualized treatment.

Methods

Omics data and clinical data for two HCC cohorts were derived from the Cancer Genome Atlas (TCGA) and the International Cancer Genome Atlas (ICGC), respectively. CNV data and methylation data were downloaded from the GSCA database. GSVA was used to estimate the transcriptional activity of KEGG pathways, and consensus clustering was used to categorize the HCC samples. The pRRophetic package was used to predict the sensitivity of samples to anticancer drugs. TIMER, MCPcounter, quanTIseq, and TIDE algorithms were used to assess the components of TME. LASSO and COX analyses were used to establish a prognostic gene signature. The biological role played by genes in HCC cells was confirmed by in vitro experiments.

Results

We classified HCC tissues into two categories based on the activity of prognostic pathways. Among them, the transcriptional profile of cluster A HCC is similar to that of normal tissue, dominated by cancer-suppressive metabolic pathways, and has a better prognosis. In contrast, cluster B HCC is dominated by high proliferative activity and has significant genetic heterogeneity. Meanwhile, cluster B HCC is often poorly differentiated, has a high rate of serum AFP positivity, is prone to microvascular invasion, and has shorter overall survival. In addition, we found that mutations, copy number variations, and aberrant methylation were also crucial drivers of the differences in heterogeneity between the two HCC subtypes. Meanwhile, the TME of the two HCC subtypes is also significantly different, which offers the possibility of precision immunotherapy for HCC patients. Finally, based on the prognostic value of molecular subtypes, we developed a gene signature that could accurately predict patients' OS. The riskscore quantified by the signature could evaluate the heterogeneity of HCC and guide clinical treatment. Finally, we confirmed through in vitro experiments that RFPL4B could promote the progression of Huh7 cells.

Conclusion

The molecular subtypes we identified effectively exposed the heterogeneity of HCC, which is important for discovering new effective therapeutic targets.

Development and therapeutic potential of DNA-dependent protein kinase inhibitors

The deployment of DNA damage response (DDR) combats various forms of DNA damage, ensuring genomic stability. Cancer cells' propensity for genomic instability offers therapeutic opportunities to selectively kill cancer cells by suppressing the DDR pathway. DNA-dependent protein kinase (DNA-PK), a nuclear serine/threonine kinase, is crucial for the non-homologous end joining (NHEJ) pathway in the repair of DNA double-strand breaks (DSBs). Therefore, targeting DNA-PK is a promising cancer treatment strategy. This review elaborates on the structures of DNA-PK and its related large protein, as well as the development process of DNA-PK inhibitors, and recent advancements in their clinical application. We emphasize our analysis of the development process and structure-activity relationships (SARs) of DNA-PK inhibitors based on different scaffolds. We hope this review will provide practical information for researchers seeking to develop novel DNA-PK inhibitors in the future.

Molecular regulation of DNA damage and repair in female infertility: a systematic review

DNA damage is a key factor affecting gametogenesis and embryo development. The integrity and stability of DNA are fundamental to a woman's successful conception, embryonic development, pregnancy and the production of healthy offspring. Aging, reactive oxygen species, radiation therapy, and chemotherapy often induce oocyte DNA damage, diminished ovarian reserve, and infertility in women. With the increase of infertility population, there is an increasing need to study the relationship between infertility related diseases and DNA damage and repair. Researchers have tried various methods to reduce DNA damage in oocytes and enhance their DNA repair capabilities in an attempt to protect oocytes. In this review, we summarize recent advances in the DNA damage response mechanisms in infertility diseases such as PCOS, endometriosis, diminished ovarian reserve and hydrosalpinx, which has important implications for fertility preservation.

Platinum-based chemotherapy: trends in organic nanodelivery systems

Despite the investment in platinum drugs research, cisplatin, carboplatin and oxaliplatin are still the only Pt-based compounds used as first line treatments for several cancers, with a few other compounds being approved for administration in some Asian countries. However, due to the severe and worldwide impact of oncological diseases, there is an urge for improved chemotherapeutic approaches. Furthermore, the pharmaceutical application of platinum complexes is hindered by their inherent toxicity and acquired resistance. Nanodelivery systems rose as a key strategy to overcome these challenges, with recognized versatility and ability towards improving the safety, bioavailability and efficacy of the available drugs. Among the known nanocarriers, organic systems have been widely applied, taking advantage of their potential as drug vehicles. Researchers have mainly focused on the development of lipidic and polymeric carriers, including supramolecular structures, with an overall improvement of encapsulated platinum complexes. Herein, an overview of recent trends and strategies is presented, with the main focus on the encapsulation of platinum compounds into organic nanocarriers, showcasing the evolution in the design and development of these promising systems. This comprehensive review highlights formulation methods as well as characterization procedures, providing insights that may be helpful for the development of novel platinum nanocarriers aiming at future pharmaceutical applications.

The multifaceted functions of DNA-PKcs: implications for the therapy of human diseases

The DNA-dependent protein kinase (DNA-PK), catalytic subunit, also known as DNA-PKcs, is complexed with the heterodimer Ku70/Ku80 to form DNA-PK holoenzyme, which is well recognized as initiator in the nonhomologous end joining (NHEJ) repair after double strand break (DSB). During NHEJ, DNA-PKcs is essential for both DNA end processing and end joining. Besides its classical function in DSB repair, DNA-PKcs also shows multifaceted functions in various biological activities such as class switch recombination (CSR) and variable (V) diversity (D) joining (J) recombination in B/T lymphocytes development, innate immunity through cGAS-STING pathway, transcription, alternative splicing, and so on, which are dependent on its function in NHEJ or not. Moreover, DNA-PKcs deficiency has been proven to be related with human diseases such as neurological pathogenesis, cancer, immunological disorder, and so on through different mechanisms. Therefore, it is imperative to summarize the latest findings about DNA-PKcs and diseases for better targeting DNA-PKcs, which have shown efficacy in cancer treatment in preclinical models. Here, we discuss the multifaceted roles of DNA-PKcs in human diseases, meanwhile, we discuss the progresses of DNA-PKcs inhibitors and their potential in clinical trials. The most updated review about DNA-PKcs will hopefully provide insights and ideas to understand DNA-PKcs associated diseases.

The mutagenic consequences of defective DNA repair

Multiple separate repair mechanisms safeguard the genome against various types of DNA damage, and their failure can increase the rate of spontaneous mutagenesis. The malfunction of distinct repair mechanisms leads to genomic instability through different mutagenic processes. For example, defective mismatch repair causes high base substitution rates and microsatellite instability, whereas homologous recombination deficiency is characteristically associated with deletions and chromosome instability. This review presents a comprehensive collection of all mutagenic phenotypes associated with the loss of each DNA repair mechanism, drawing on data from a variety of model organisms and mutagenesis assays, and placing greatest emphasis on systematic analyses of human cancer datasets. We describe the latest theories on the mechanism of each mutagenic process, often explained by reliance on an alternative repair pathway or the error-prone replication of unrepaired, damaged DNA. Aided by the concept of mutational signatures, the genomic phenotypes can be used in cancer diagnosis to identify defective DNA repair pathways.

Pan-cancer analysis of the disulfidptosis-related gene RPN1 and its potential biological function and prognostic significance in gliomas

Background

Numerous studies have shown a strong correlation between disulfidptosis and various cancers. However, the expression and function of RPN1, a crucial gene in disulfidptosis, remain unclear in the context of cancer.

Methods

Gene expression and clinical information on lung adenocarcinoma were obtained from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases. RPN1 expression was analyzed using the Timer2.0 and the Human Protein Atlas (HPA) databases. Prognostic significance was assessed using Cox regression analysis and Kaplan-Meier curves. Genetic mutations and methylation levels were examined using the cBioPortal and UALCAN platforms, respectively. The relationship between RPN1 and tumor mutation burden (TMB) and microsatellite instability (MSI) across different cancer types was analyzed using the Spearman correlation coefficient. The relationship between RPN1 and immune cell infiltration was analyzed using the Timer2.0 database, whereas variations in drug sensitivity were explored using the CellMiner database. Receiver operating characteristic curves validated RPN1's diagnostic potential in glioma, and its correlation with immune checkpoint inhibitors (ICIs) was assessed using Spearman's correlation coefficient. Single-sample gene set enrichment analysis elucidated a link between RPN1 and immune cells and pathways. In addition, a nomogram based on RPN1 was developed to predict patient prognosis. The functional impact of RPN1 on glioma cells was confirmed using scratch and Transwell assays.

Result

RPN1 was aberrantly expressed in various cancers and affected patient prognosis. The main mutation type of RPN1 in the cancer was amplified. RPN1 exhibited a positive correlation with myeloid-derived suppressor cells, neutrophils, and macrophages, and a negative correlation with CD8+ T cells and hematopoietic stem cells. RPN1 expression was associated with TMB and MSI in various cancers. The expression of RPN1 affected drug sensitivity in cancer cells. RPN1 was positively correlated with multiple ICIs in gliomas. RPN1 also affected immune cell infiltration into the tumor microenvironment. RPN1 was an independent prognostic factor for gliomas, and the nomogram demonstrated excellent predictive performance. Interference with RPN1 expression reduces the migratory and invasive ability of glioma cells.

Conclusion

RPN1 exerts multifaceted effects on different stages of cancer, including immune infiltration, prognosis, and treatment outcomes. RPN1 expression affects the prognosis and immune microenvironment infiltration in patients with glioma, making RPN1 a potential target for the treatment of glioma.

Pathogenic variants in human DNA damage repair genes mostly arose after the latest human out-of-Africa migration

Introduction

The DNA damage repair (DDR) system in human genome is pivotal in maintaining genomic integrity. Pathogenic variation (PV) in DDR genes impairs their function, leading to genome instability and increased susceptibility to diseases, especially cancer. Understanding the evolution origin and arising time of DDR PV is crucial for comprehending disease susceptibility in modern humans.

Methods

We used big data approach to identify the PVs in DDR genes in modern humans. We mined multiple genomic databases derived from 251,214 modern humans of African and non-Africans. We compared the DDR PVs between African and non-African. We also mined the DDR PVs in the genomic data derived from 5,031 ancient humans. We used the DDR PVs from ancient humans as the intermediate to further the DDR PVs between African and non-African.

Results and discussion

We identified 1,060 single-base DDR PVs across 77 DDR genes in modern humans of African and non-African. Direct comparison of the DDR PVs between African and non-African showed that 82.1% of the non-African PVs were not present in African. We further identified 397 single-base DDR PVs in 56 DDR genes in the 5,031 ancient humans dated between 45,045 and 100 years before present (BP) lived in Eurasian continent therefore the descendants of the latest out-of-Africa human migrants occurred 50,000-60,000 years ago. By referring to the ancient DDR PVs, we observed that 276 of the 397 (70.3%) ancient DDR PVs were exclusive in non-African, 106 (26.7%) were shared between non-African and African, and only 15 (3.8%) were exclusive in African. We further validated the distribution pattern by testing the PVs in BRCA and TP53, two of the important genes in genome stability maintenance, in African, non-African, and Ancient humans. Our study revealed that DDR PVs in modern humans mostly emerged after the latest out-of-Africa migration. The data provides a foundation to understand the evolutionary basis of disease susceptibility, in particular cancer, in modern humans.

Somatic and intergenerational G4C2 hexanucleotide repeat instability in a human C9orf72 knock-in mouse model

Expansion of a G4C2 repeat in the C9orf72 gene is associated with familial Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD). To investigate the underlying mechanisms of repeat instability, which occurs both somatically and intergenerationally, we created a novel mouse model of familial ALS/FTD that harbors 96 copies of G4C2 repeats at a humanized C9orf72 locus. In mouse embryonic stem cells, we observed two modes of repeat expansion. First, we noted minor increases in repeat length per expansion event, which was dependent on a mismatch repair pathway protein Msh2. Second, we found major increases in repeat length per event when a DNA double- or single-strand break (DSB/SSB) was artificially introduced proximal to the repeats, and which was dependent on the homology-directed repair (HDR) pathway. In mice, the first mode primarily drove somatic repeat expansion. Major changes in repeat length, including expansion, were observed when SSB was introduced in one-cell embryos, or intergenerationally without DSB/SSB introduction if G4C2 repeats exceeded 400 copies, although spontaneous HDR-mediated expansion has yet to be identified. These findings provide a novel strategy to model repeat expansion in a non-human genome and offer insights into the mechanism behind C9orf72 G4C2 repeat instability.

BER genes expression in oral and pre-oral cancer: Combinatorial approach to propose potential biomarker

OBJECTIVE

DNA repair genes and their variants have been found to alter the risk of oral cancer.

METHOD

The level of expression of XRCC3, NBS1, and OGG1 genes among 20 cases of oral cancer, 6 pre-oral cancer, and 50 healthy control subjects was measured with RT-PCR. All the subjects were also genotyped for XRCC3 rs861539 C>T, NBS1 rs1805794 C>G, and OGG1 rs1052133 C>G polymorphisms by the PCR-RFLP method; their genotypes were correlated with their level of expression. Further, a localized fold structure analysis of the mRNA sequence surrounding the studied SNPs was performed with RNAfold.

RESULTS

Results showed increased expression of XRCC3, NBS1, and OGG1 transcripts among oral cancer (4.49 fold, 3.45 fold, and 3.27 fold) as well as pre-oral cancer (3.04 fold, 5.32 fold, and 1.74 fold) as compared to control subjects. The transcript level of OGG1 was found to be significantly increased (6.68 fold, p-value 0.009) with the GG genotype compared to the CC genotype. The C>T polymorphism of XRCC3 and the C>G polymorphism of OGG1 result in an apparent change in its mRNA secondary structure. Folding energy with the C allele for XRCC3 C>T polymorphism was lower than that of the T allele (MFE C vs T: -50.20 kcal/mol vs -48.70 kcal/mol). In the case of OGG1 C>G polymorphism MFE for the C allele was higher (-23.30 kcal/mole) than with the G allele (-24.80 kcal/mol).

CONCLUSION

Our results showed elevated levels of XRCC3, NBS1, and OGG1 both in oral cancer and pre-oral cancer conditions, which indicates their role as prospective biomarkers of oral cancer and pre-cancerous lesions. SNPs in these genes alter their level of expression, possibly by altering the secondary structure of their transcript. However, due to the small sample size our study can only provide a suggestive conclusion and warned future study with large sample size to verify our findings.

Evolutionary feedback from the environment shapes mechanisms that generate genome variation

Darwin recognized that 'a grand and almost untrodden field of inquiry will be opened, on the causes and laws of variation.' However, because the Modern Synthesis assumes that the intrinsic probability of any individual mutation is unrelated to that mutation's potential adaptive value, attention has been focused on selection rather than on the intrinsic generation of variation. Yet many examples illustrate that the term 'random' mutation, as widely understood, is inaccurate. The probabilities of distinct classes of variation are neither evenly distributed across a genome nor invariant over time, nor unrelated to their potential adaptive value. Because selection acts upon variation, multiple biochemical mechanisms can and have evolved that increase the relative probability of adaptive mutations. In effect, the generation of heritable variation is in a feedback loop with selection, such that those mechanisms that tend to generate variants that survive recurring challenges in the environment would be captured by this survival and thus inherited and accumulated within lineages of genomes. Moreover, because genome variation is affected by a wide range of biochemical processes, genome variation can be regulated. Biochemical mechanisms that sense stress, from lack of nutrients to DNA damage, can increase the probability of specific classes of variation. A deeper understanding of evolution involves attention to the evolution of, and environmental influences upon, the intrinsic variation generated in gametes, in other words upon the biochemical mechanisms that generate variation across generations. These concepts have profound implications for the types of questions that can and should be asked, as omics databases become more comprehensive, detection methods more sensitive, and computation and experimental analyses even more high throughput and thus capable of revealing the intrinsic generation of variation in individual gametes. These concepts also have profound implications for evolutionary theory, which, upon reflection it will be argued, predicts that selection would increase the probability of generating adaptive mutations, in other words, predicts that the ability to evolve itself evolves.

An analysis of AURKB's prognostic and immunological roles across various cancers

Aurora kinase B (AURKB), an essential regulator in the process of mitosis, has been revealed through various studies to have a significant role in cancer development and progression. However, the specific mechanisms remain poorly understood. This study, therefore, seeks to elucidate the multifaceted role of AURKB in diverse cancer types. This study utilized bioinformatics techniques to examine the transcript, protein, promoter methylation and mutation levels of AURKB. The study further analysed associations between AURKB and factors such as prognosis, pathological stage, biological function, immune infiltration, tumour mutational burden (TMB) and microsatellite instability (MSI). In addition, immunohistochemical staining data of 50 cases of renal clear cell carcinoma and its adjacent normal tissues were collected to verify the difference in protein expression of AURKB in the two tissues. The results show that AURKB is highly expressed in most cancers, and the protein level of AURKB and the methylation level of its promoter vary among cancer types. Survival analysis showed that AURKB was associated with overall survival in 12 cancer types and progression-free survival in 11 cancer types. Elevated levels of AURKB were detected in the advanced stages of 10 different cancers. AURKB has a potential impact on cancer progression through its effects on cell cycle regulation as well as inflammatory and immune-related pathways. We observed a strong association between AURKB and immune cell infiltration, immunomodulatory factors, TMB and MSI. Importantly, we confirmed that the AURKB protein is highly expressed in kidney renal clear cell carcinoma (KIRC). Our study reveals that AURKB may be a potential biomarker for pan-cancer and KIRC.

DNA double-strand break repair capacity and its pathway gene variants predict the risk and prognosis of lung cancer

OBJECTIVES

This study aims to investigate the association between DNA double-strand breaks (DSBs) repair capacity, variations in DSBs-related genes, and the occurrence and prognosis of lung cancer in the Chinese population.

METHODS

Peripheral blood mononuclear cells (PBMC) were collected from 98 lung cancer patients and 60 healthy individuals. The individual DSBs repair capacity was assessed by measuring changes in γ-H2AX levels after treatment with etoposide. Exonic sequencing of 45 DSBs-related genes was performed on PBMC DNA. Logistic regression analysis was conducted to examine the relationship between lung cancer risk and DSBs repair capacity as well as germlines gene variations. Survival analysis employed the Cox proportional hazards regression model, Kaplan-Meier method, and Log-rank test.

RESULTS

Lower DSBs repair capacity predicted an increased risk of developing lung cancer (OR = 0.94, 95 %CI = 0.917-0.964, P＜0.001). Among lung cancer patients, higher DSBs repair capacity was associated with shorter progression-free survival (PFS) during first-line treatment (HR = 1.80, 95 %CI = 1.10-3.00, P = 0.031). Patients with BRCA1 mutations had shorter overall survival (OS) (HR = 1.92, 95 %CI = 1.12-3.28, P = 0.018). Patients with FOXO3 mutations had shorter PFS (HR = 4.23, 95 %CI = 1.44-12.36, P = 0.009). Analysis of patients treated with immune checkpoint inhibitors (ICIs) indicated that LIG4 mutations were associated with shorter PFS (HR = 2.90, 95 %CI = 1.00-8.10, P = 0.041).

CONCLUSIONS

This study concludes that assessing DSBs repair capacity holds promise for predicting both lung cancer risk and prognosis in the Chinese population. Further large-scale studies and functional validation of specific gene mutations related to double-strand breaks are necessary for confirmation.