EGFR exon 19-deletion aberrantly regulate ERCC1 expression that may partly impaired DNA damage repair ability in non-small cell lung cancer

A Novel DNA Repair-Gene Model to Predict Responses to Immunotherapy and Prognosis in Patients With EGFR-Mutant Non-Small Cell Lung Cancer

BACKGROUND

The epidermal growth factor receptor mutant (EGFRm) non-small cell lung cancer (NSCLC) has a unique "cold" immune profile. DNA damage repair (DDR) genes are closely related to tumorigenesis and the effectiveness of immunotherapy in many tumors. However, the role and mechanism of DDR in the genesis and progression of EGFRm NSCLC remain unclear.

METHODS

This study included 101 EGFRm NSCLC samples from The Cancer Genome Atlas (TCGA) dataset and a GSE31210 dataset (external set) from the GEO database. Cluster analysis was used to identify different subtypes of EGFRm NSCLC based on the expression of DDR genes. Univariate and LASSO regression analysis was used to develop a DDR-based predictive model. The prognostic significance of this model was assessed using Cox regression, Kaplan-Meier, and receiver operating characteristic (ROC) curve analyses. Bioinformatics analysis was performed to investigate the clinicopathological characteristics and immune profiles associated with this model. In vitro experiment was performed to testify the role of DDR genes in EGFRm NSCLC.

RESULTS

We identified two subtypes of EGFRm NSCLC: DDR-activated and DDR-suppressed. The DDR-activated subtype showed more aggressive clinical behavior and poorer prognosis and was more responsive to immunotherapy. A prognostic model for EGFRm NSCLC was constructed using four DDR genes: CAPS, FAM83A, IGLV8-61, and SLC7A5. The derived risk score could serve as an independent prognostic indicator. High- and low-risk patients exhibited distinct clinicopathological characteristics, immune profiles, and responses to immunotherapy. The T-cell inflammation and Tumor Immune Dysfunction and Exclusion (TIDE) scores differed between the high- and low-risk subgroups, with both showing enhanced effectiveness of immunotherapy in the low-risk subgroup. Targeted therapy such as BI.2536, an inhibitor of polo-like kinase 1, could be effective for patients with high-risk EGFRm NSCLC. Meanwhile, in vitro detection approved the role of DDR genes in EGFRm NSCLC response.

CONCLUSION

This study demonstrated a diversity of DDR genes in EGFRm NSCLC and developed a predictive model using these genes. This model could assist in identifying potential candidates for immunotherapy and in assessing personalized treatment and prognosis of patients with EGFRm NSCLC.

Strength of selection in lung tumors correlates with clinical features better than tumor mutation burden

Single nucleotide substitutions are the most common type of somatic mutations in cancer genome. The goal of this study was to use publicly available somatic mutation data to quantify negative and positive selection in individual lung tumors and test how strength of directional and absolute selection is associated with clinical features. The analysis found a significant variation in strength of selection (both negative and positive) among tumors, with median selection tending to be negative even though tumors with strong positive selection also exist. Strength of selection estimated as the density of missense mutations relative to the density of silent mutations showed only a weak correlation with tumor mutation burden. In the "all histology together" analysis we found that absolute strength of selection was strongly correlated with all clinically relevant features analyzed. In histology-stratified analysis selection was strongest in small cell lung cancer. Selection in adenocarcinoma was somewhat higher compared to squamous cell carcinoma. The study suggests that somatic mutation- based quantifying of directional and absolute selection in individual tumors can be a useful biomarker of tumor aggressiveness.

Clinical translation for targeting DNA damage repair in non-small cell lung cancer: a review

Despite significant advancements in screening, diagnosis, and treatment of non-small cell lung cancer (NSCLC), it remains the primary cause of cancer-related deaths globally. DNA damage is caused by the exposure to exogenous and endogenous factors and the correct functioning of DNA damage repair (DDR) is essential to maintain of normal cell circulation. The presence of genomic instability, which results from defective DDR, is a critical characteristic of cancer. The changes promote the accumulation of mutations, which are implicated in cancer cells, but these may be exploited for anti-cancer therapies. NSCLC has a distinct genomic profile compared to other tumors, making precision medicine essential for targeting actionable gene mutations. Although various treatment options for NSCLC exist including chemotherapy, targeted therapy, and immunotherapy, drug resistance inevitably arises. The identification of deleterious DDR mutations in 49.6% of NSCLC patients has led to the development of novel target therapies that have the potential to improve patient outcomes. Synthetic lethal treatment using poly (ADP-ribose) polymerase (PARP) inhibitors is a breakthrough in biomarker-driven therapy. Additionally, promising new compounds targeting DDR, such as ATR, CHK1, CHK2, DNA-PK, and WEE1, had demonstrated great potential for tumor selectivity. In this review, we provide an overview of DDR pathways and discuss the clinical translation of DDR inhibitors in NSCLC, including their application as single agents or in combination with chemotherapy, radiotherapy, and immunotherapy.

Gene network analysis of oxaliplatin-resistant colorectal cancer to target a crucial gene using chitosan/hyaluronic acid/protamine polyplexes containing CRISPR-Cas9

Colorectal cancer (CRC) treatment is dramatically hampered by resistance to oxaliplatin alone or in the combination of irinotecan or 5-fluorouracil and leucovorin. This study aims to design and assess Chitosan/Hyaluronic Acid/Protamine sulfate (CS/HA/PS) polyplexes loaded with CRISPR plasmid for targeting a key gene in cancer drug resistance. Here, recent findings were considered to validate oxaliplatin-resistant CRC-related genes and systems biology approaches employed to detect the critical gene. The polyplexes were characterized according to particle size, zeta potential, and stability. Moreover, carrier toxicity and transfection efficiency were assessed on oxaliplatin-resistant HT-29 cells. The post-transfection evaluations were performed to confirm gene disruption-mediated CRISPR. Eventually, excision cross complementation group 1(ERCC1), a crucial member of the nucleotide excision repair pathway, was selected to be targeted using CRISPR/Cas9 to reverse oxaliplatin resistance in HT-29 cells. CS/HA/PS polyplexes containing CRISPR/Cas9 plasmid exhibited negligible toxicity and comparable transfection efficiency with Lipofectamine™. Following the efficient gene delivery, sequences in CRISPR/Cas9 target sites were altered, ERCC1 was downregulated, and drug sensitivity was successfully restored in oxaliplatin-resistant cells. Findings indicate that CS/HA/PS/CRISPR polyplexes provide a potential strategy for delivering cargo and targeting oxaliplatin resistance-related gene to manipulate drug resistance as a rising concern in cancer therapeutic approaches.

Experimental study of EGFR-TKI aumolertinib combined with ionizing radiation in EGFR mutated NSCLC brain metastases tumor

Aumolertinib is an irreversible third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), although it has been administered for the treatment of epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC). However, it is unclear whether aumolertinib combined with ionizing radiation (IR) has potential therapeutic effects in treating brain metastases (BM) tumors from NSCLC. This study explored the anti-tumor effects of aumolertinib combined with IR in epidermal growth factor receptor mutated (EGFRm) NSCLC BM tumors. First, we established a xenograft model of NSCLC BM tumors in BALB/c nude mice and assessed the anti-tumor effects of this combination. Furthermore, we examined the concentrations of aumolertinib in brain tissue and blood using liquid chromatography-mass spectrometry (LC-MS); after that, we used CCK-8, colony formation, flow cytometry assay, and immunofluorescence staining to detect the effects of aumolertinib combined with IR upon PC-9 and NCI-H1975 cells, such as cell proliferation, survival, apoptosis, cycle distribution, the situation of DNA damage, and the expression levels of relevant proteins which were detected via western blotting; finally, we chose a clinical case with which to explore the clinical benefits to the EGFRm NSCLC BM patient after the treatment of the aforementioned combination. The experiments of NSCLC BM tumor animal models demonstrated that the combination enhanced the therapeutic effects and increased the intracranial accumulation of aumolertinib; the combination can inhibit cell proliferation and survival, delay the repair of DNA damage, and increase the rates of cell apoptosis and aumolertinib abrogated G2/M phase arrest, which the IR induced; the clinical study verified that the combination demonstrated better patient benefits. In conclusion, our study demonstrated that combining aumolertinib and IR has promising anti-tumor effects in EGFR-mutant NSCLC and that this combined treatment modality may be employed as a potential therapeutic strategy for EGFR-mutant NSCLC BM patients clinically.

Humoral immune response to epidermal growth factor receptor in lung cancer

The aim of this study was to explore the potential value of autoantibody to epidermal growth factor receptor (EGFR) in the diagnosis of lung cancer (LC) and its relation with EGFR mutations. Enzyme-linked immunosorbent assay (ELISA) was performed to detect the level of autoantibody to EGFR in sera from 254 LC patients and 222 normal controls (NCs). Besides, the mRNA and protein levels of EGFR were investigated in Gene Expression Profiling Interactive Analysis (GEPIA) and Human Protein Atlas (HPA) database, respectively. The level of autoantibody to EGFR (anti-EGFR) in LC even different types of LC was obviously higher than that in NC (P < 0.05). The area under the curve (AUC) of anti-EGFR was 0.695 (95% CI 0.645-0.742) when comparing LC patients with NC, while the AUC of carcinoembryonic antigen (CEA) was 0.681 (95% CI 0.629-0.730). Moreover, by integrating anti-EGFR with CEA to diagnose LC, the AUC was up to 0.784 (95% CI 0.737-0.826). However, the expression level of autoantibody to EGFR had no difference between LC patients with and without EGFR gene mutation (P > 0.05). EGFR mRNA expression level was obviously upregulated in squamous cell carcinoma (SCC) tissues compared with normal tissues (P < 0.05), but not in adenocarcinoma (ADC) (P > 0.05). The study confirmed that anti-EGFR could be a potential biomarker for LC diagnosis; additionally, it could improve the diagnostic value of CEA in clinical work.

Association of hOGG1-Cys variants with occurrence of p53 and EGFR deletion mutations in non-small cell lung cancer

Background

The human 8‐oxoguanine DNA glycosylase 1 (hOGG1) gene encodes a DNA glycosylase that removes 8‐hydroxy‐2‐deoxyguanine (8‐OH‐dG) DNA damage to protect against gene mutations. The association of hOGG1 Ser326Cys polymorphism with lung cancer risk has predicted that hOGG1‐Cys variants are less effective at removing 8‐OH‐dG damage from DNA; therefore, these variants might show an increased occurrence of tumor suppressor gene and oncogene mutations. However, no evidence has yet supported this hypothesis.

Methods

Direct sequencing was performed to examine the mutations of p53 and EGFR genes in lung tumors from patients with non‐small cell lung cancer (NSCLC). Polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) was used to examine hOGG1 Ser326Cys polymorphism in this study population.

Results

A total of 99 p53‐mutated and 99 EGFR‐mutated patients with NSCLC were selected to explore the possible associations of these mutations with hOGG1 Ser326Cys polymorphism. The p53‐mutated and EGFR‐mutated patients were divided into nondeletion and deletion subgroups. P53 deletion mutations were more commonly observed in male than in female patients (P = 0.030). However, EGFR exon 19 deletion mutations were more prevalent in female and adenocarcinoma patients than in male and squamous cell carcinoma patients (P = 0.028 for genders, P = 0.017 for tumor histology). Interestingly, p53 and EGFR exon 19 deletion mutations were more frequent in patients with hOGG1 Ser/Cys + Cys/Cys hOGG1‐Cys variants than with the hOGG1 Ser/Ser genotype (P = 0.010 for p53, P = 0.032 for EGFR).

Conclusions

We suggest that the association of hOGG1 Ser326Cys polymorphism with lung cancer risk could be partially explained by increases in p53 and EGFR deletion mutations.

Key points

Significant findings of the study

NSCLC patients with hOGG1‐Cys variants may have a higher risk of p53 and EGFR deletion mutations than with hOGG1 Ser/Ser genotype.

What this study adds

NSCLC patients with hOGG1‐Cys variants might be helpful to predict patients having higher risk of EGFR exon 19 deletion mutations and these patients who were treated with gefitinib or erlotinib could be a higher risk to occur EGFR T790M mutation.

NSCLC patients with hOGG1‐Cys variants may have higher risk of p53 and EGFR deletion mutations than with hOGG1 Ser/Ser genotype. NSCLC patients with hOGG1‐Cys variants might be helpful to predict patients with higher risk of EGFR exon 19 deletion mutations and these patients who were treated with gefitinib and erlotinib were more common to occur EGFR T790M mutation.