Overexpression of NEIL3 associated with altered genome and poor survival in selected types of human cancer

Dysregulation of base excision repair factors associated with low tumor immunogenicity in head and neck cancer: implication for immunotherapy

Background

Head and neck squamous carcinoma (HNSCC) is caused by different exogenous risk factors including smoking cigarettes, alcohol consumption, and HPV infection. Base excision repair (BER) is the frontline to repair oxidative DNA damage, which is initiated by the DNA N-glycosylase proteins (OGG1) and other BER factors including DNA polymerase β (POLB).

Objective

Explore whether BER genes' (OGG1, POLB) overexpression in HNSCC alters genomic integrity, immunogenicity, and its role in prognostic value.

Design

RNA sequencing (RNA-Seq) and clinical information (age, gender, histological grade, survival status, and stage) of 530 patients of HNSCC were retrieved from the Cancer Genome Atlas. Patients' data are categorized HPV positive or negative to analyze the tumor data including the tumor stage, POLB, and OGG1 gene expression.

Methods

RNA-Seq of HNSCC data retrieved and mutation count and aneuploidy score were compared using an unpaired t-test. The TIMER algorithm was used to calculate the tumor abundance of six infiltrating immune cells (CD4+ T cells, CD8+ T cells, B cells, neutrophils, macrophages, and dendritic cells) based on RNA-Seq expression profile data. The correlation between the POLB, OGG1, and immune cells was calculated by Spearman correlation analysis using TIMER 2.0.

Results

Our data analysis reveals that BER genes frequently overexpressed in HNSCC tumors and increase mutation count. In addition, OGG1 and POLB overexpression are associated with low infiltration of immune cells, low immune checkpoint gene expression (PD-1, cytotoxic T-lymphocyte antigen 4, program death ligand 1, and program death ligand 2), and innate immune signaling genes. Furthermore, dysregulated BER factors in Human papillomavirus (HPV) positive tumors had better overall survival.

Conclusion

Our analysis suggests that dysregulation of the BER genes panel might be a potential prognosis marker and/or an attractive target for an immune checkpoint blockade in HNSCC cancers. However, our observation still requires further experimental-based scientific validation studies.

Identification of prognostic models for glycosylation-related subtypes and tumor microenvironment infiltration characteristics in clear cell renal cell cancer

Background

One of the most fatal forms of cancer of the urinary system, renal cell carcinoma (RCC), significantly negatively impacts human health. Recent research reveals that abnormal glycosylation contributes to the growth and spread of tumors. However, there is no information on the function of genes related to glycosylation in RCC.

Methods

In this study, we created a technique that can be used to guide the choice of immunotherapy and chemotherapy regimens for RCC patients while predicting their survival prognosis. The Cancer Genome Atlas (TCGA) provided us with patient information, while the GeneCards database allowed us to collect genes involved in glycosylation. GSE29609 was used as external validation to assess the accuracy of prognostic models. The "ConsensusClusterPlus" program created molecular subtypes based on genes relevant to glycosylation discovered using differential expression analysis and univariate Cox analysis. We examined immune cell infiltration as measured by estimate, CIBERSORT, TIMER, and ssGSEA algorithms, Tumor Immune Dysfunction and Exclusion (TIDE) and exclusion of tumour stemness indices (TSIs) based on glycosylation-related molecular subtypes and risk profiles. Stratification, somatic mutation, nomogram creation, and chemotherapy response prediction were carried out based on risk factors.

Results

We built and verified 16 gene signatures associated with the prognosis of ccRCC patients, which are independent prognostic variables, and identified glycosylation-related genes by bioinformatics research. Cluster 2 is associated with lower human leukocyte antigen expression, worse overall survival, higher immunological checkpoints, and higher immune escape scores. In addition, cluster 2 had significantly better angiogenic activity, mesenchymal EMT, and stem ability scores. Higher immune checkpoint genes and human leukocyte antigens are associated with lower overall survival and a higher risk score. Higher estimated and immune scores, lesser tumor purity, lower mesenchymal EMT, and higher stem scores were all characteristics of the high-risk group. High amounts of tumor-infiltrating lymphocytes, a high mutation load, and a high copy number alteration frequency were present in the high-risk group.Discussion.According to our research, the 16-gene prognostic signature may be helpful in predicting prognosis and developing individualized treatments for patients with renal clear cell carcinoma, which may result in new personalized management options for these patients.

Integrating single-cell and bulk expression data to identify and analyze cancer prognosis-related genes

Compared with traditional evaluation methods of cancer prognosis based on tissue samples, single-cell sequencing technology can provide information on cell type heterogeneity for predicting biomarkers related to cancer prognosis. Therefore, the bulk and single-cell expression profiles of breast cancer and normal cells were comprehensively analyzed to identify malignant and non-malignant markers and construct a reliable prognosis model. We first screened highly reliable differentially expressed genes from bulk expression profiles of multiple breast cancer tissues and normal tissues, and inferred genes related to cell malignancy from single-cell data. Then we identified eight critical genes related to breast cancer to conduct Cox regression analysis, calculate polygenic risk score (PRS), and verify the predictive ability of PRS in two data groups. The results show that PRS can divide breast cancer patients into high-risk group and low-risk group. PRS is related to the overall survival time and relapse-free interval and is a prognosis factor independent of conventional clinicopathological characteristics. Breast cancer is usually regarded as a cancer with a relatively good prognosis. In order to further explore whether this workflow can be applied to cancer with poor prognosis, we selected lung cancer for a comparative study. The results show that this workflow can also build a reasonable prognosis model for lung cancer. This study provides new insight and practical source code for further research on cancer biomarkers and drug targets. It also provides basis for survival prediction, treatment response prediction, and personalized treatment.

NEIL3 promotes cell proliferation of ccRCC via the cyclin D1-Rb-E2F1 feedback loop regulation

Nei endonuclease VIII-like 3 (NEIL3), a novel tumor-related gene, is differentially expressed and involved in pathophysiological processes in multiple tumors. However, the potential biological functions and molecular mechanisms of NEIL3 in human clear cell renal cell carcinoma (ccRCC) have not been identified. In this research, we demonstrated that NEIL3, transcriptionally activated by E2F1, served as an oncogene to facilitate cell proliferation and cell cycle progression and contribute to tumorigenesis via the cyclin D1-Rb-E2F1 feedback loop in ccRCC. First, we found that NEIL3 expression was upregulated in ccRCC tissues and cell lines compared with matched adjacent nontumor tissues and renal tubular epithelial cells and was also positively correlated with adverse clinicopathological characteristics, such as advanced cancer stages and higher tumor grades, and acted as an independent prognostic marker in ccRCC. Mechanistically, we demonstrated that NEIL3 promoted cell proliferation, DNA replication and cell cycle progression in vitro and tumor growth in vivo. Furthermore, we found that NEIL3 overexpression activated the cyclin D1-Rb-E2F1 pathway, and the E2F1 upregulation transcriptionally activated NEIL3 expression, thus forming a feedback loop. In addition, there was a positive correlation between NEIL3 and E2F1 expression in clinical specimens of ccRCC. Taken together, our results suggest that NEIL3 serves as a proto-oncogene in ccRCC and presents as a novel candidate for ccRCC diagnosis and treatment.

Transcriptional factor MAZ promotes cisplatin-induced DNA damage repair in lung adenocarcinoma by regulating NEIL3

BACKGROUND

Cisplatin remains a common chemotherapy drug for lung adenocarcinoma (LUAD) in clinical treatment. Long-term use of cisplatin in patients may lead to acquired drug resistance, resulting in poor prognoses of patients. NEIL3 was a glycosylase-encoding gene highly expressed in LUAD. NEIL3 can repair telomerase DNA damage in the S phase. Nevertheless, there are few reports on whether NEIL3 is involved in cisplatin resistance and its related mechanisms in LUAD.

METHODS

The expression of NEIL3 in LUAD patients was analyzed by bioinformatics. The regulator upstream of NEIL3 was predicted via hTFtarget. The possibly involved pathways of NEIL3 were obtained by performing Gene Set Enrichment Analysis. qRT-PCR and western blot were applied to test the expression level of genes and protein LUAD cells. Dual-luciferase assay and chromatin immunoprecipitation (ChIP) assay were conducted to validate the binding relationship between MAZ and NEIL3. Cell function assays were performed to test the DNA damage, cell viability, cell migration and invasion, and cell cycle of LUAD cells in the treatment group.

RESULTS

NEIL3 and its upstream regulatory factor MAZ were highly expressed in LUAD tissue, and NEIL3 was enriched in cell cycle and mismatch repair pathways. Dual-luciferase assay and ChIP assay proved that MAZ could target NEIL3. Cell experiments identified that MAZ/NEIL3 axis could repress DNA damage to advance cisplatin resistance of cancer cells, and foster cell migration and invasion in LUAD.

CONCLUSION

MAZ-activated NEIL3 could propel the cisplatin resistance in LUAD by repressing DNA damage.

NEIL3-mediated proteasomal degradation facilitates the repair of cisplatin-induced DNA damage in human cells

Anti-neoplastic effect of DNA cross-linking agents such as cisplatin, mitomycin C, and psoralen is attributed to their ability to induce DNA interstrand cross-links (ICLs), which block replication, transcription, and linear repair pathways by preventing DNA strand separation and trigger apoptosis. It is generally agreed that the Fanconi anemia (FA) pathway orchestrates the removal of ICLs by the combined actions of various DNA repair pathways. Recently, attention has been focused on the ability of the NEIL3-initiated base excision repair pathway to resolve psoralen- and abasic site-induced ICLs in an FA-independent manner. Intriguingly, overexpression of NEIL3 is associated with chemo-resistance and poor prognosis in many solid tumors. Here, using loss- and gain-of-function approaches, we demonstrate that NEIL3 confers resistance to cisplatin and participates in the removal of cisplatin-DNA adducts. Proteomic studies reveal that the NEIL3 protein interacts with the 26S proteasome in a cisplatin-dependent manner. NEIL3 mediates proteasomal degradation of WRNIP1, a protein involved in the early step of ICL repair. We propose that NEIL3 participates in the repair of ICL-stalled replication fork by recruitment of the proteasome to ensure a timely transition from lesion recognition to repair via the degradation of early-step vanguard proteins.

Pan-Cancer Landscape of NEIL3 in Tumor Microenvironment: A Promising Predictor for Chemotherapy and Immunotherapy

With the aim of enhancing the understanding of NEIL3 in prognosis prediction and therapy administration, we conducted a pan-cancer landscape analysis on NEIL3. The mutation characteristics, survival patterns, and immune features of NEIL3 across cancers were analyzed. Western blotting, qPCR, and immunohistochemistry were conducted to validate the bioinformatics results. The correlation between NEIL3 and chemotherapeutic drugs, as well as immunotherapies, was estimated. NEIL3 was identified as an oncogene with prognostic value in predicting clinical outcomes in multiple cancers. Combined with the neoantigen, tumor mutational burden (TMB), and microsatellite instability (MSI) results, a strong relationship between NEIL3 and the TME was observed. NEIL3 was demonstrated to be closely associated with multiple immune parameters, including infiltrating immunocytes and pro-inflammatory chemokines, which was verified by experiments. More importantly, patients with a higher expression of NEIL3 were revealed to be more sensitive to chemotherapeutic regimens and immune checkpoint inhibitors in selected cancers, implying that NEIL3 may be an indicator for therapeutic administration. Our study indicated NEIL3 has a strong association with the immune microenvironment and phenotypic changes in certain types of cancers, which facilitated the improved understanding of NEIL3 across cancers and highlighted the potential for clinical application of NEIL3 in precision medical stratification.

Biological Functions of the DNA Glycosylase NEIL3 and Its Role in Disease Progression Including Cancer

The accumulation of oxidative DNA base damage can severely disrupt the integrity of the genome and is strongly associated with the development of cancer. DNA glycosylase is the critical enzyme that initiates the base excision repair (BER) pathway, recognizing and excising damaged bases. The Nei endonuclease VIII-like 3 (NEIL3) is an emerging DNA glycosylase essential in maintaining genome stability. With an in-depth study of the structure and function of NEIL3, we found that it has properties related to the process of base damage repair. For example, it not only prefers the base damage of single-stranded DNA (ssDNA), G-quadruplex and DNA interstrand crosslinks (ICLs), but also participates in the maintenance of replication fork stability and telomere integrity. In addition, NEIL3 is strongly associated with the progression of cancers and cardiovascular and neurological diseases, is incredibly significantly overexpressed in cancers, and may become an independent prognostic marker for cancer patients. Interestingly, circNEIL3, a circular RNA of exon-encoded origin by NEIL3, also promotes the development of multiple cancers. In this review, we have summarized the structure and the characteristics of NEIL3 to repair base damage. We have focused on NEIL3 and circNEIL3 in cancer development, progression and prognosis.

Identification of Candidate Genes in Breast Cancer Induced by Estrogen Plus Progestogens Using Bioinformatic Analysis

Menopausal hormone therapy (MHT) was widely used to treat menopause-related symptoms in menopausal women. However, MHT therapies were controversial with the increased risk of breast cancer because of different estrogen and progestogen combinations, and the molecular basis behind this phenomenon is currently not understood. To address this issue, we identified differentially expressed genes (DEGs) between the estrogen plus progestogens treatment (EPT) and estrogen treatment (ET) using the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) data. As a result, a total of 96 upregulated DEGs were first identified. Seven DEGs related to the cell cycle (CCNE2, CDCA5, RAD51, TCF19, KNTC1, MCM10, and NEIL3) were validated by RT-qPCR. Specifically, these seven DEGs were increased in EPT compared to ET (p < 0.05) and had higher expression levels in breast cancer than adjacent normal tissues (p < 0.05). Next, we found that estrogen receptor (ER)-positive breast cancer patients with a higher CNNE2 expression have a shorter overall survival time (p < 0.05), while this effect was not observed in the other six DEGs (p > 0.05). Interestingly, the molecular docking results showed that CCNE2 might bind to 17β-estradiol (−6.791 kcal/mol), progesterone (−6.847 kcal/mol), and medroxyprogesterone acetate (−6.314 kcal/mol) with a relatively strong binding affinity, respectively. Importantly, CNNE2 protein level could be upregulated with EPT and attenuated by estrogen receptor antagonist, acolbifene and had interactions with cancer driver genes (AKT1 and KRAS) and high mutation frequency gene (TP53 and PTEN) in breast cancer patients. In conclusion, the current study showed that CCNE2, CDCA5, RAD51, TCF19, KNTC1, MCM10, and NEIL3 might contribute to EPT-related tumorigenesis in breast cancer, with CCNE2 might be a sensitive risk indicator of breast cancer risk in women using MHT.

TRIM26 Maintains Cell Survival in Response to Oxidative Stress through Regulating DNA Glycosylase Stability

Oxidative DNA base lesions in DNA are repaired through the base excision repair (BER) pathway, which consequently plays a vital role in the maintenance of genome integrity and in suppressing mutagenesis. 8-oxoguanine DNA glycosylase (OGG1), endonuclease III-like protein 1 (NTH1), and the endonuclease VIII-like proteins 1-3 (NEIL1-3) are the key enzymes that initiate repair through the excision of the oxidized base. We have previously identified that the E3 ubiquitin ligase tripartite motif 26 (TRIM26) controls the cellular response to oxidative stress through regulating both NEIL1 and NTH1, although its potential, broader role in BER is unclear. We now show that TRIM26 is a central player in determining the response to different forms of oxidative stress. Using siRNA-mediated knockdowns, we demonstrate that the resistance of cells to X-ray radiation and hydrogen peroxide generated as a consequence of trim26 depletion can be reversed through suppression of selective DNA glycosylases. In particular, a knockdown of neil1 or ogg1 can enhance sensitivity and DNA repair rates in response to X-rays, whereas a knockdown of neil1 or neil3 can produce the same effect in response to hydrogen peroxide. Our study, therefore, highlights the importance of TRIM26 in balancing cellular DNA glycosylase levels required for an efficient BER response.

Role of germline variants in the metastasis of breast carcinomas

Most cancer-related deaths in breast cancer patients are associated with metastasis, a multistep, intricate process that requires the cooperation of tumour cells, tumour microenvironment and metastasis target tissues. It is accepted that metastasis does not depend on the tumour characteristics but the host’s genetic makeup. However, there has been limited success in determining the germline genetic variants that influence metastasis development, mainly because of the limitations of traditional genome-wide association studies to detect the relevant genetic polymorphisms underlying complex phenotypes. In this work, we leveraged the extreme discordant phenotypes approach and the epistasis networks to analyse the genotypes of 97 breast cancer patients. We found that the host’s genetic makeup facilitates metastases by the dysregulation of gene expression that can promote the dispersion of metastatic seeds and help establish the metastatic niche—providing a congenial soil for the metastatic seeds.

NEIL3 Mediates Lung Cancer Progression and Modulates PI3K/AKT/mTOR Signaling: A Potential Therapeutic Target

Background. Nei endonuclease VIII-like 3 (NEIL3) is widely involved in pathophysiological processes of the body; however, its role in lung cancer has not been conclusively determined. Objective. This study is aimed at exploring the role of NEIL3 in lung cancer. Methods. The public data used in this study were downloaded from The Cancer Genome Atlas (TCGA) database. “Limma” in R was used for the analysis of differentially expressed genes. Clinical correlations and prognostic analyses were performed using the survival package in R. The proliferative abilities of lung cancer cells were evaluated by the CCK8 and colony formation assays while their invasive and migration abilities were assessed by the transwell and wound healing assays. Quantitative real-time PCR (qRT-PCR) and western blot analyses were utilized to detect RNA and protein levels. Biological differences between groups were determined by gene set enrichment analysis (GSEA). Tumor Immune Dysfunction and Exclusion (TIDE) as well as Genomics of Drug Sensitivity in Cancer (GDSC) was used for immunotherapeutic and chemotherapeutic sensitivity analyses. Results. NEIL3 was upregulated in NSCLC tissues and cell lines, implying that it is involved in lung cancer initiation and progression. Clinical correlation and prognostic analyses showed that NEIL3 was associated with worse clinical features (stage and T and N classifications) and poor prognostic outcomes. In vitro, NEIL3 significantly enhanced NSCLC proliferation, invasion, and migration. GSEA indicated that NEIL3 might be involved in PI3K/AKT/mTOR, G2/M checkpoints, and E2F target pathways. Inhibition of NEIL3 suppressed cyclinD1 and p-AKT protein levels; however, it had no effects on AKT levels, indicating that NEIL3 can partially activate the PI3K/AKT/mTOR signaling pathway. The predicted result of TIDE indicated that immunotherapeutic nonresponders had elevated NEIL3 levels. Moreover, there was a positive correlation between NEIL3 levels and chemosensitivity to cisplatin and paclitaxel. Conclusion. In general, NEIL3 mediates NSCLC progression and affects sensitivity to immunotherapy and chemotherapy; therefore, it is a potential molecular target for treatment.

In Silico Analysis of the Correlation of KIF2C with Prognosis and Immune Infiltration in Glioma

Glioblastoma (GBM) is one of the most commonly pivotal malignant caners. Numerous reports have revealed the crucial roles of immune infiltration in the initiation and progression of GBM. In this study, we first identified differentially expressed genes (DEGs) in the progression of GBM using CGGA databases. Totally, 156 upregulated DEGs and 251 downregulated DEGs were revealed. By constructing a protein-protein interaction network, KIF2C was identified as a hub gene in GBM. Further analysis revealed an evidently positive association existing in KIF2C expression and the advanced stages of gliomas. Higher expression of KIF2C was in WHO grade IV samples relative to that in grade III and grade II samples. In addition, our results showed that KIF2C was higher in IDH1 wild-type samples than IDH1 mutant glioma samples, in 1p/19q noncodel samples than 1p/19q code glioma samples, and in recurrent samples than primary glioma samples. Moreover, our results showed that higher expression of KIF2C correlated with shorter survival time in both primary and recurrent gliomas and could act as a potential biomarker for the prognosis of GBM. Further analysis demonstrated that higher expression of KIF2C was related to higher levels of endothelial cell, T cell CD8+ naïve, common lymphoid progenitor, T cell CD4+ Th2, T cell CD4+ Th2, macrophage, macrophage M1, T cell CD4+ memory, and T cell CD4+ effector memory, but was related to lower levels of NK cell, B cell plasma, T cell CD4+ Th1, T cell regulatory (Tregs), neutrophil, and T cell NK. We thought this study could provide potential biomarkers for the prediction of prognosis and immune infiltration of gliomas.

Identification of the Signature Genes and Network of Reactive Oxygen Species Related Genes and DNA Repair Genes in Lung Adenocarcinoma

Reactive Oxygen Species (ROS) are present in excess amounts in patients with tumors, and these ROS can kill and destroy tumor cells. Therefore, tumor cells upregulate ROS-related genes to protect them and reduce their destructing effects. Cancer cells already damaged by ROS can be repaired by expressing DNA repair genes consequently promoting their proliferation. The present study aimed to identify the signature genes of and regulating network of ROS-related genes and DNA repair genes in lung adenocarcinoma (LUAD) using transcriptomic data of public databases. The LUAD transcriptome data in the TCGA database and gene expressions from Gene Expression Omnibus (GEO) were analyzed and samples were clustered into 5 ROS-related categories and 6 DNA repair categories. Survival analysis revealed a significant difference in patient survival between the two classification methods. In addition, the samples corresponding to the two categories overlap, thus, the gene expression profile of the same sample with different categories and survival prognosis was further explored, and the connection between ROS-related and DNA repair genes was investigated. The interactive sample recombination classification was used, revealing that the patient's prognosis was worse when the ROS-related and DNA repair genes were expressed at the same time. The further research on the potential regulatory network of the two categories of genes and the correlation analysis revealed that ROS-related genes and DNA repair genes have a mutual regulatory relationship. The ROS-related genes namely NQO1, TXNRD1, and PRDX4 could establish links with other DNA repair genes through the DNA repair gene NEIL3, thereby balancing the level of ROS. Therefore, targeting ROS-related genes and DNA repair genes might be a promising strategy in the treatment of LUAD. Finally, a survival prognostic model of ROS-related genes and DNA repair genes was established (TERT, PRKDC, PTTG1, SMUG1, TXNRD1, CAT, H2AFX, and PFKP). The risk score obtained from our survival prognostic model could be used as an independent prognostic factor in LUAD patients.

Identification of DNA Damage Repair-Associated Prognostic Biomarkers for Prostate Cancer Using Transcriptomic Data Analysis

In the recent decade, the importance of DNA damage repair (DDR) and its clinical application have been firmly recognized in prostate cancer (PC). For example, olaparib was just approved in May 2020 to treat metastatic castration-resistant PC with homologous recombination repair-mutated genes; however, not all patients can benefit from olaparib, and the treatment response depends on patient-specific mutations. This highlights the need to understand the detailed DDR biology further and develop DDR-based biomarkers. In this study, we establish a four-gene panel of which the expression is significantly associated with overall survival (OS) and progression-free survival (PFS) in PC patients from the TCGA-PRAD database. This panel includes DNTT, EXO1, NEIL3, and EME2 genes. Patients with higher expression of the four identified genes have significantly worse OS and PFS. This significance also exists in a multivariate Cox regression model adjusting for age, PSA, TNM stages, and Gleason scores. Moreover, the expression of the four-gene panel is highly correlated with aggressiveness based on well-known PAM50 and PCS subtyping classifiers. Using publicly available databases, we successfully validate the four-gene panel as having the potential to serve as a prognostic and predictive biomarker for PC specifically based on DDR biology.

NEIL3 contributes toward the carcinogenesis of liver cancer and regulates PI3K/Akt/mTOR signaling

Liver cancer is one of the top three fatal types of cancer and it causes several thousands of mortalities each year. The main treatment is surgical resection which shows little benefit for patients with recurrence or metastasis. NEIL3 promotes progression and predicts survival in cancer. However, its role in liver cancer remains unclear. Based on data in the TCGA database, NEIL3 exhibited much higher expression in liver cancer tissues and was clinically correlated with tumor grade in patients with liver cancer. Furthermore, high NEIL3 expression caused shorter survival times. In liver cancer cell lines, NEIL3 showed abundant expression. When NEIL3 was knocked down in HepG2 and Huh-7 cells, cell abilities including proliferation, growth, migration and invasion, exhibited deficiency to different extents. Cell cycle transition was blocked at the G2 phase and the cell apoptotic rate increased notably. In addition, the phosphorylation levels of Akt, PI3K and mTOR were increased following NEIL3-overexpression but decreased following NEIL3-knockdown. In conclusion, NEIL3 contributes toward development and/or progression in liver cancer and regulates PI3K/Akt/mTOR signaling.

NEIL3 may act as a potential prognostic biomarker for lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is the leading cause of cancer-related death. This study aimed to develop and validate reliable prognostic biomarkers and signature.

METHODS

Differentially expressed genes were identified based on three Gene Expression Omnibus (GEO) datasets. Based on 1052 samples' data from our cohort, GEO and The Cancer Genome Atlas, we explored the relationship of clinicopathological features and NEIL3 expression to determine clinical effect of NEIL3 in LUAD. Western blotting (22 pairs of tumor and normal tissues), Real-time quantitative PCR (19 pairs of tumor and normal tissues), and immunohistochemical analyses (406-tumor tissues subjected to microarray) were conducted. TIMER and ImmuCellAI analyzed relationship between NEIL3 expression and the abundance of tumor-infiltrating immune cells in LUAD. The co-expressed-gene prognostic signature was established based on the Cox regression analysis.

RESULTS

This study identified 502 common differentially expressed genes and confirmed that NEIL3 was significantly overexpressed in LUAD samples (P < 0.001). Increased NEIL3 expression was related to advanced stage, larger tumor size and poor overall survival (p < 0.001) in three LUAD cohorts. The proportions of natural T regulatory cells and induced T regulatory cells increased in the high NEIL3 group, whereas those of B cells, Th17 cells and dendritic cells decreased. Gene set enrichment analysis indicated that NEIL3 may activate cell cycle progression and P53 signaling pathway, leading to poor outcomes. We identified nine prognosis-associated hub genes among 370 genes co-expressed with NEIL3. A 10-gene prognostic signature including NEIL3 and nine key co-expressed genes was constructed. Higher risk-score was correlated with more advanced stage, larger tumor size and worse outcome (p < 0.05). Finally, the signature was verified in test cohort (GSE50081) with superior diagnostic accuracy.

CONCLUSIONS

This study suggested that NEIL3 has the potential to be an immune-related therapeutic target and an independent predictor of LUAD prognosis. We also developed a prognostic signature for LUAD with a precise diagnostic accuracy.

The overexpression of DNA repair genes in invasive ductal and lobular breast carcinomas: Insights on individual variations and precision medicine

In the era of precision medicine, analyzing the transcriptomic profile of patients is essential to tailor the appropriate therapy. In this study, we explored transcriptional differences between two invasive breast cancer subtypes; infiltrating ductal carcinoma (IDC) and lobular carcinoma (LC) using RNA-Seq data deposited in the TCGA-BRCA project. We revealed 3854 differentially expressed genes between normal ductal tissues and IDC. In addition, IDC to LC comparison resulted in 663 differentially expressed genes. We then focused on DNA repair genes because of their known effects on patients' response to therapy and resistance. We here report that 36 DNA repair genes are overexpressed in a significant number of both IDC and LC patients' samples. Despite the upregulation in a significant number of samples, we observed a noticeable variation in the expression levels of the repair genes across patients of the same cancer subtype. The same trend is valid for the expression of miRNAs, where remarkable variations between patients' samples of the same cancer subtype are also observed. These individual variations could lie behind the differential response of patients to treatment. The future of cancer diagnostics and therapy will inevitably depend on high-throughput genomic and transcriptomic data analysis. However, we propose that performing analysis on individual patients rather than a big set of patients' samples will be necessary to ensure that the best treatment is determined, and therapy resistance is reduced.

Focus on DNA Glycosylases-A Set of Tightly Regulated Enzymes with a High Potential as Anticancer Drug Targets

Cancer is the second leading cause of death with tens of millions of people diagnosed with cancer every year around the world. Most radio- and chemotherapies aim to eliminate cancer cells, notably by causing severe damage to the DNA. However, efficient repair of such damage represents a common mechanism of resistance to initially effective cytotoxic agents. Thus, development of new generation anticancer drugs that target DNA repair pathways, and more particularly the base excision repair (BER) pathway that is responsible for removal of damaged bases, is of growing interest. The BER pathway is initiated by a set of enzymes known as DNA glycosylases. Unlike several downstream BER enzymes, DNA glycosylases have so far received little attention and the development of specific inhibitors of these enzymes has been lagging. Yet, dysregulation of DNA glycosylases is also known to play a central role in numerous cancers and at different stages of the disease, and thus inhibiting DNA glycosylases is now considered a valid strategy to eliminate cancer cells. This review provides a detailed overview of the activities of DNA glycosylases in normal and cancer cells, their modes of regulation, and their potential as anticancer drug targets.