Nuclear survivin and its relationship to DNA damage repair genes in non-small cell lung cancer investigated using tissue array

Tissue microarray analyses of the essential DNA repair factors ATM, DNA-PKcs and Ku80 in head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) negative for Human Papillomavirus (HPV) has remained a difficult to treat entity, whereas tumors positive for HPV are characterized by radiosensitivity and favorable patient outcome. On the cellular level, radiosensitivity is largely governed by the tumor cells` ability to repair radiation-induced DNA double-strand breaks (DSBs), but no biomarker is established that could guide clinical decision making. Therefore, we tested the impact of the expression levels of ATM, the central kinase of the DNA damage response as well as DNA-PKcs and Ku80, two major factors in the main DSB repair pathway non-homologous end joining (NHEJ).

METHODS

A tissue microarray of a single center HNSCC cohort was stained for ATM, DNA-PKcs and Ku80 and the expression scored based on staining intensity and the percentages of tumor cells stained. Scores were correlated with clinicopathological parameters and survival.

RESULTS

Samples from 427 HNSCC patients yielded interpretable stainings and were scored following an established algorithm. The majority of tumors showed strong expression of both NHEJ factors, whereas the expression of ATM varied more. The expression scores of ATM and DNA-PKcs were not associated with patient survival. For HPV-negative HNSCC, the minority of tumors without strong Ku80 expression trended towards superior survival when treatment included radiotherapy. Focusing stronger on staining intensity to define the subgroup with lowest and therefore potentially insufficient expression levels in the HPV-negative subgroup, we observed significantly better overall survival for patients treated with radiotherapy but not with surgery alone.

CONCLUSIONS

Our data suggest that HPV-negative HNSCC with particularly low Ku80 expression represent a highly radiosensitive subpopulation. Confirmation in independent cohorts is required.

Expression of immune checkpoint PD-1 in non-small cell lung cancer is associated with tumor cell DNA-dependent protein kinase

Immunotherapy using immune checkpoint inhibitors has demonstrated durable responses and has significantly improved survival in patients with non-small cell lung cancer (NSCLC). Moreover, immunotherapy is increasingly used in combination with cytotoxic treatments such as chemotherapy and radiotherapy. Although the combined treatments are more effective, the underling mechanisms that lead to higher antitumor activity are not fully understood. Therefore, the aim of the current retrospective study was to determine the relationship between expression of immune checkpoints [programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1)] and the enzyme DNA-dependent protein kinase (DNA-PK), which is part of a key pathway involved in the repair of cytotoxic cancer therapy induced damage. Surgically excised NSCLC tissues (n=121) were histologically examined for overall extent of inflammation (score 0-3). Expression levels of PD-1 (number of PD-1 positive cells), PD-L1 [tumor proportion score (TPS); %] and DNA-PK (proportion of DNA-PK positive tumor cells; %) were determined using immunohistochemistry. Expressions of these markers were compared in different clinicopathological subgroups and later used for nonparametric Spearman correlation analysis to determine associations. In patients with NSCLC, PD-1 was significantly expressed in males (P=0.030) and in patients with no or trivial inflammation scores (P=0.030). PD-L1 expression was also significantly higher in current smokers (P=0.025). Correlation analysis was based on the individual values of patients and revealed a significant association between one of the targets of immune checkpoint inhibitors and tumor cell DNA-PK. Tumors with higher numbers of PD-1 positive cells also demonstrated higher tumor cell DNA-PK expressions (P=0.027). The results demonstrated a significant positive correlation between the PD-1/PD-L1 axis and tumor cell DNA-PK expression in patients with NSCLC. Further studies are required to clarify the significance of this correlation and its effect on the efficacy of immunotherapy and cytotoxic cancer therapy combinations.

Clinicopathological and Prognostic Significance of Inhibitor of Apoptosis Protein (IAP) Family Members in Lung Cancer: A Meta-Analysis

Lung cancer is the most common cause of cancer-related death worldwide. Approximately 85% is non-small-cell and 15% is small-cell lung cancer. The inhibitor of apoptosis proteins (IAPs) represent a heterogeneous family of anti-apoptotic proteins, some members of which have been reported to correlate with clinical outcome in lung cancer. We screened PubMed, Web of Science, and Scopus for studies that investigated the prognostic value and clinicopathological features of IAPs in lung cancer. Forty-five eligible studies with 4428 patients assessed the expression of the IAPs survivin, XIAP, livin, and BRUCE. The pooled hazard ratio (HR) of 33 studies that analyzed overall survival (OS) revealed a positive correlation between survivin expression and poor prognosis. Seven studies displayed a strong association between survivin and disease recurrence. Two studies that assessed the expression of XIAP and livin, respectively, proved a significant relationship of these IAPs with poor OS. Meta-analyses of clinicopathological variables revealed a significant association between survivin and T stage, UICC stage, the presence of lymph node metastasis, and grade of differentiation. In conclusion, high expression of distinct IAPs significantly correlates with prognosis in lung cancer. Therefore, lung cancer patients might benefit from a targeted therapy against specific IAPs.

Comparative Transcriptional Analysis of Pulmonary Arterial Hypertension Associated With Three Different Diseases

Pulmonary arterial hypertension (PAH) is a severe cardiovascular disorder with high mortality. Multiple clinical diseases can induce PAH, but the underlying molecular mechanisms shared in PAHs associated with different diseases remain unclear. The aim of this study is to explore the key candidate genes and pathways in PAH associated with congenital heart disease (CHD-PAH), PAH associated with connective tissue disease (CTD-PAH), and idiopathic PAH (IPAH). We performed differential expression analysis based on a public microarray dataset GSE113439 and identified 1,442 differentially expressed genes, of which 80.3% were upregulated. Subsequently, both pathway enrichment analysis and protein–protein interaction network analysis revealed that the “Cell cycle” and “DNA damage” processes were significantly enriched in PAH. The expression of seven upregulated candidate genes (EIF2AK2, TOPBP1, CDC5L, DHX15, and CUL1–3) and three downregulated candidate genes (DLL4, EGFL7, and ACE) were validated by qRT-PCR. Furthermore, cell cycle-related genes Cul1 and Cul2 were identified in pulmonary arterial endothelial cells (PAECs) in vitro. The result revealed an increased expression of Cul2 in PAECs after hypoxic treatment. Silencing Cul2 could inhibit overproliferation and migration of PAECs in hypoxia. Taken together, according to bioinformatic analyses, our work revealed that “Cell cycle” and “DNA damage” process-related genes and pathways were significantly dysregulated expressed in PAHs associated with three different diseases. This commonality in molecular discovery might broaden the genetic perspective and understanding of PAH. Besides, silencing Cul2 showed a protective effect in PAECs in hypoxia. The results may provide new treatment targets in multiple diseases induced by PAH.

Survivin as a biological biomarker for diagnosis and therapy

Introduction: Survivin (SVN) is a member of the inhibitor of apoptosis (IAP) protein family that promotes cellular proliferation and inhibits apoptosis. Overexpression of SVN is associated with autoimmune disease, hyperplasia, and tumors and can be used as a biomarker in these diseases. SVN is widely recognized as a tumor-associated antigen (TAA) and has become an important target for cancer diagnosis and treatment.Areas covered: We reviewed SVN research progress from the PubMed and clinical trials focused on SVN from https://clinicaltrials.gov since 2000 and anticipate future developments in the field. The trials reviewed cover various modalities including diagnostics for early detection and disease progression, small molecule inhibitors of the SVN pathway and immunotherapy targeting SVN epitopes.Expert opinion: The most promising developments involve anti-SVN immunotherapy, with several therapeutic SVN vaccines under evaluation in phase I/II trials. SVN is an important new immune-oncology target that expands the repertoire of individualized combination treatments for cancer.

Druggable binding sites in the multicomponent assemblies that characterise DNA double-strand-break repair through non-homologous end joining

Non-homologous end joining (NHEJ) is one of the two principal damage repair pathways for DNA double-strand breaks in cells. In this review, we give a brief overview of the system including a discussion of the effects of deregulation of NHEJ components in carcinogenesis and resistance to cancer therapy. We then discuss the relevance of targeting NHEJ components pharmacologically as a potential cancer therapy and review previous approaches to orthosteric regulation of NHEJ factors. Given the limited success of previous investigations to develop inhibitors against individual components, we give a brief discussion of the recent advances in computational and structural biology that allow us to explore different targets, with a particular focus on modulating protein-protein interaction interfaces. We illustrate this discussion with three examples showcasing some current approaches to developing protein-protein interaction inhibitors to modulate the assembly of NHEJ multiprotein complexes in space and time.

miR-101-3p sensitizes lung adenocarcinoma cells to irradiation via targeting BIRC5

Lung adenocarcinoma (LUAD) has been considered as the most common cause of cancer-associated mortality. Radiotherapy resistance is one of the main reasons for LUAD treatment failure. The microRNA (miR)-101-3p has been previously reported to function as a tumor suppressor in several types of cancer, including LUAD. The present study aimed to explore the role and mechanism of miR-101-3p on radioresistance of lung adenocarcinoma cells through bioinformatics analysis and biological experiments. Based on the analysis of Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) data, it was demonstrated that the expression of miR-101-3p was low in LUAD tissues compared with normal lung tissues and was associated with poor prognosis of patients with LUAD. The results of the CCK-8 assay, colony formation assay, immunofluorescence staining, caspase-3 activity assay and western blotting demonstrated that miR-101-3p overexpression sensitized LUAD cells to ionizing radiation by decreasing the abilities of LUAD cell proliferation, colony formation, DNA damage repair and increasing caspase-3 activity and apoptosis of LUAD cells following ionizing radiation. Furthermore, according to bioinformatics analysis and luciferase assay, baculoviral IAP repeat containing 5 (BIRC5) was identified as a direct target of miR-101-3p. Increased BIRC5 expression reversed the miR-101-3p-mediated increase in LUAD cell radiotherapy sensitivity. Taken together, the results of the present study demonstrated that miR-101-3p may be considered as a potential target that can enhance LUAD cell sensitivity to radiotherapy, which may provide a new strategy to improve therapy in patients with LUAD.

Identification and validation of an autophagy-related long non-coding RNA signature as a prognostic biomarker for patients with lung adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is the most predominant pathological subtype of lung cancer, accounting for 40–70% of all lung cancer cases. Although significant improvements have been made in the screening, diagnosis, and precise management in recent years, the prognosis of LUAD remains bleak. This study aimed to investigate the prognostic significance of autophagy-related long non-coding RNAs (lncRNAs) and construct an autophagy-related lncRNA prognostic model in LUAD.

Methods

The gene expression data of LUAD patients were obtained from The Cancer Genome Atlas (TCGA) database. All autophagy-related genes were downloaded from the Human Autophagy Database (HADb). Spearman’s correlation test was exploited to identify potential autophagy-related lncRNAs. The multivariate Cox regression analysis was used to construct the prognostic signature, which divided LUAD patients into high-risk and low-risk groups. Subsequently, the receiver operating characteristic (ROC) curves were generated to assess the predictive ability of this prognostic model for overall survival (OS) in these individuals. Then, the Gene set enrichment analysis (GSEA) was conducted to execute pathway enrichment analysis. Finally, a multidimensional validation was exploited to verify our findings.

Results

A total of 1,144 autophagy-related lncRNAs were identified to construct the co-expression network via Spearman’s correlation test (|R²| >0.4 and P≤0.001). Ultimately, a 16 autophagy-related lncRNAs prognostic model was constructed, and the area under the ROC curve (AUC) was 0.775. The results of GSEA enrichment analysis showed that the genes in the high-risk group were mainly enriched in cell cycle and p53 signaling pathways. The results of the multidimensional database validation indicated that the expression level of BIRC5 was significantly correlated with the expression level of TMPO-AS1. Furthermore, both TMPO-AS1 and BIRC5 had a higher expression level in LUAD samples. LUAD patients with high expression levels of TMPO-AS1 and BIRC5 were correlated with advanced disease stage and poor OS.

Conclusions

In summary, our results suggested that the prognostic signature of the 16 autophagy-related lncRNAs has significant prognostic value for LUAD patients. Furthermore, TMPO-AS1 and BIRC5 are potential predictors and therapeutic targets in these individuals.

DNA-dependent protein kinase: effect on DSB repair, G2/M checkpoint and mode of cell death in NSCLC cell lines

Purpose: To evaluate the effect of NU7026, a specific inhibitor of DNA-PKcs, on DNA-double strand break (DSB) repair in a cell cycle specific manner, on the G2/M checkpoint, mitotic progression, apoptosis and clonogenic survival in non-small-cell lung carcinoma (NSCLC) cell lines with different p53 status. Material and methods: Cell cycle progression, and hyperploidy were evaluated using flow cytometry. Polynucleation as a measure for mitotic catastrophe (MC) was evaluated by fluorescence microscopy. DSB induction and repair were measured by constant-gel electrophoresis and γH2AX assay. The efficiency of DSB rejoining during the cell cycle was assessed by distinguishing G1 and G2/M phase cells on the basis of the DNA content in flow cytometry. The overall effect on cell death was determined by apoptosis and the surviving fraction after irradiation with 2 Gy (SF2) assessed by clonogenic survival. Results: DSB signaling upon treatment with NU7026, as measured by γH2AX signaling, was differently affected in G1 and G2/M cells. The background level of γH2AX was significantly higher in G2/M compared to G1 cells, whereas NU7026 had no effect on the background level. The steepness of the initial dose effect relation at 1 h after irradiation was less pronounced in G2/M compared to G1 cells. NU7026 had no significant effect on the initial dose-effect relation of γH2AX signaling. In comparison, NU7026 significantly slowed down the repair kinetics and increased the residual γH2AX signal at 24 h after irradiation in the G1 phase of all cell lines, but was less effective in G2/M cells. NU7026 significantly increased the fraction of G2/M phase cells upon irradiation. Moreover, NU7026 significantly increased mitotic catastrophe and hyperploidy, as a measure for mitotic failure after low irradiation doses of about 4 Gy, but decreased both at higher doses of 20 Gy. In addition, radiation induced apoptosis increased in A549, H520 and H460 but decreased in H661 upon NU7026 treatment, with a significant reduction of SF2 in all NSCLC cell lines. Conclusion: Overall, NU7026 significantly influences the cell cycle progression through the G2- and M-phases and thereby determines the fate of cells. The impairment of DNA-PK upon treatment with NU7026 affects the efficiency of the NHEJ system in a cell cycle dependent manner, which may be of relevance for a clinical application of DNA-PK inhibitors in tumor therapy.

Survivin is a prognostic marker and therapeutic target for extranodal, nasal-type natural killer/T cell lymphoma

Background

The relationship between survivin and extranodal, nasal-type natural killer/T cell lymphoma (ENKTCL) was unclearly established yet. We here studied the potential prognostic roles of survivin and its implication as a target in ENKTCL therapy.

Methods

ENKTCL patients' peripheral blood were collected and tested by ELISA. ENKTCL cell lines were cultured with or without survivin inhibitor and tested by MTT and Flow cytometry. According to the gene expression profiles from the ArrayExpress Archive under E-TABM-702, survivin co-regulated cluster was established by Coupled Two-way Clustering Algorithm.

Results

Seventeen point six percent of total 17 ENKTCL patients were serum survivin-positive. These patients had poorer outcome than that of negative cases (P<0.01). Analysis of survivin co-regulation genes in ENKTCL revealed that survivin was significantly involved in pluripotency, drug resistance, cell cycle and proliferation, indicating that it should be one of key regulators in ENKTCL and might be a latent therapeutic target. Our results just showed that YM155, a survivin inhibitor, had strong anti-tumor effect on ENKTCL cell lines in a dose dependent manner. It increased sub-G1 phase population and reduced G1- and G2-M phase populations (P<0.05). In addition, combining YM155 with DDP induced a larger decrease in cell viability than either agent alone and had a higher inhibition rate than Bliss index, suggesting their synergistic inhibition.

Conclusions

We concluded that survivin was a potential prognostic marker and a critical regulatory molecule in the pathological process of ENKTCL. It would be a promising target in drugs discovery for ENKTCL therapy.

[Advances in molecular mechanism of vascular remodeling in pulmonary arterial hypertension]

Pulmonary arterial hypertension (PAH) is a clinical hemodynamic syndrome characterized by elevated pulmonary arterial pressure and pulmonary vascular resistance leading to right heart failure and death. Vascular remodeling is the most prominent histopathological feature of PAH, which is regulated by many factors. Endoplasmic reticulum stress, calcium disorder and mitochondrial dysfunction are involved in the vascular cell proliferation and apoptosis by regulating intracellular calcium homeostasis and cellular metabolism. Epigenetic phenomenon such as DNA damage and abnormal expression of miRNA are also involved in the regulation of abnormal proliferation of vascular cells. Vascular cell phenotype switching including endothelial-mesenchymal transition and smooth muscle cell phenotype switching play an important role in abnormal proliferation of vascular cells. Vascular remodeling is produced by a variety of cells and molecular pathways, and aiming at multiple targets which is expected to find a new breakthrough in the treatment of PAH,and to improve abnormal vascular remodeling, delay or even reverse the progression of PAH.

Prognostic Value of BIRC5 in Lung Adenocarcinoma Lacking EGFR, KRAS, and ALK Mutations by Integrated Bioinformatics Analysis

Objective

This study was aimed at investigating the prognostic significance of Baculoviral IAP repeat containing 5 (BIRC5) in lung adenocarcinoma (LAD) lacking EGFR, KRAS, and ALK mutations (triple-negative (TN) adenocarcinomas).

Methods

The gene expression profiles were obtained from Gene Expression Omnibus (GEO). The identification of the differentially expressed genes (DEGs) was performed by GeneSpring GX. Gene set enrichment analysis (GSEA) was used to execute gene ontology function and pathway enrichment analysis. The protein interaction network was constructed by Cytoscape. The hub genes were extracted by MCODE and cytoHubba plugin from the network. Then, using BIRC5 as a candidate, the prognostic value in LAD and TN adenocarcinomas was verified by the Kaplan-Meier plotter and The Cancer Genome Atlas (TCGA) database, respectively. Finally, the mechanism of BIRC5 was predicted by a coexpressed network and enrichment analysis.

Results

A total of 38 upregulated genes and 121 downregulated genes were identified. 9 hub genes were extracted. Among them, the mRNA expression of 5 genes, namely, BIRC5, MCM4, CDC20, KIAA0101, and TRIP13, were significantly upregulated among TN adenocarcinomas (all P < 0.05). Notably, only the overexpression of BIRC5 was associated with unfavorable overall survival (OS) in TN adenocarcinomas (log rank P = 0.0037). TN adenocarcinoma patients in the BIRC5 high-expression group suffered from a significantly high risk of distant metastasis (P = 0.046), advanced N stage (P = 0.033), and tumor-bearing (P = 0.031) and deceased status (P = 0.003). The mechanism of BIRC5 and coexpressed genes may be linked closely with the cell cycle.

Conclusion

Overexpressed in tumors, BIRC5 is associated with unfavorable overall survival in TN adenocarcinomas. BIRC5 is a potential predictor and therapeutic target in TN adenocarcinomas.

The Role of the Core Non-Homologous End Joining Factors in Carcinogenesis and Cancer

DNA double-strand breaks (DSBs) are deleterious DNA lesions that if left unrepaired or are misrepaired, potentially result in chromosomal aberrations, known drivers of carcinogenesis. Pathways that direct the repair of DSBs are traditionally believed to be guardians of the genome as they protect cells from genomic instability. The prominent DSB repair pathway in human cells is the non-homologous end joining (NHEJ) pathway, which mediates template-independent re-ligation of the broken DNA molecule and is active in all phases of the cell cycle. Its role as a guardian of the genome is supported by the fact that defects in NHEJ lead to increased sensitivity to agents that induce DSBs and an increased frequency of chromosomal aberrations. Conversely, evidence from tumors and tumor cell lines has emerged that NHEJ also promotes chromosomal aberrations and genomic instability, particularly in cells that have a defect in one of the other DSB repair pathways. Collectively, the data present a conundrum: how can a single pathway both suppress and promote carcinogenesis? In this review, we will examine NHEJ's role as both a guardian and a disruptor of the genome and explain how underlying genetic context not only dictates whether NHEJ promotes or suppresses carcinogenesis, but also how it alters the response of tumors to conventional therapeutics.

DNA-PK Inhibition by NU7441 Enhances Chemosensitivity to Topoisomerase Inhibitor in Non-Small Cell Lung Carcinoma Cells by Blocking DNA Damage Repair

BACKGROUND

DNA double-strand breaks (DSBs) are the most cytotoxic form of DNA damage and are induced by ionizing radiation and specific chemotherapeutic agents, such as topoisomerase inhibitors. Cancer cells acquire resistance to such therapies by repairing DNA DSBs. A major pathway for the repair of DNA DSBs is non-homologous end-joining (NHEJ), which requires DNA-dependent protein kinase (DNA-PK) activity. In this study, we investigated the effect of NU7441, a synthetic small-molecule compound, as a specific inhibitor of DNA-PK on the chemosensitization of non-small cell lung carcinoma (NSCLC) A549 cells.

METHODS

The combined effects of chemotherapeutic agents and NU7441 were evaluated by isobologram analysis using Cell Counting Kit-8. DNA DSBs were assessed by immunofluorescence assay. Apoptosis was examined by flow cytometry using an Annexin V apoptosis kit. Activation of DNA-PK was assayed by western blotting.

RESULTS

The combination of NU7441 and topoisomerase inhibitors such as amrubicin and irinotecan had a synergistic effect on cell proliferation in A549 cells. NU7441 increased 53BP1 foci and apoptosis induced by topoisomerase inhibitors and decreased phospho-DNA-dependent protein kinase, catalytic subunit (pDNA-PKcs) (S2056) protein expression caused by topoisomerase inhibitors. Interestingly, mitotic inhibitors such as pacritaxel did not cause the pDNA-PKcs (S2056) protein expression and the combination of NU7441 and pacritaxel had an only additive effect.

CONCLUSION

NU7441 inhibited the growth of NSCLC cells and enhanced the chemosensitization to topoisomerase inhibitors by blocking DNA repair. A combination of NU7441 and topoisomerase inhibitor may be a promising treatment for NSCLC.

Prognostic significance of nuclear or cytoplasmic nucleolin expression in human non-small cell lung cancer and its relationship with DNA-PKcs

This study investigated the expression of nucleolin in tissue samples in patients with non-small cell lung cancer (NSCLC). Nucleolin was studied to determine whether it has a prognostic value and if its levels correlate with various clinicopathologic parameters. The relationship between nucleolin and expression of DNA-PKcs was also evaluated. Immunohistochemistry was used for detecting the expression levels of nucleolin and DNA-PKcs in tissues from 225 stage IA to IIIB NSCLC patients who underwent lung surgery. Nucleolin was observed predominantly in the cytoplasm, and some levels were observed in the nucleus. Nucleolin expression was higher in NSCLC tissues than adjacent normal lung tissues. Among 225 NSCLC patients, 117 (52.0 %) had high expression of nucleolin. The expression of nucleolin was significantly associated with pathologic stage (P = 0.013) and T status (P = 0.043). Multivariate analysis revealed that nucleolin, cytoplasmic nucleolin, and nuclear nucleolin expression were independent prognostic factors for both overall survival (OS) (P < 0.001) and disease-free survival (DFS) (P < 0.001). A high level of nuclear nucleolin served as an independent prognostic factor for better survival, while a high level of cytoplasmic nucleolin was closely associated with worse prognosis in NSCLC patients. The expression of nucleolin and cytoplasmic nucleolin positively correlated with DNA-PKcs (P < 0.001). These data suggest that nucleolin could be an effective treatment target and prognostic factor for patients with NSCLC.

DNA Damage and Pulmonary Hypertension

Pulmonary hypertension (PH) is defined by a mean pulmonary arterial pressure over 25 mmHg at rest and is diagnosed by right heart catheterization. Among the different groups of PH, pulmonary arterial hypertension (PAH) is characterized by a progressive obstruction of distal pulmonary arteries, related to endothelial cell dysfunction and vascular cell proliferation, which leads to an increased pulmonary vascular resistance, right ventricular hypertrophy, and right heart failure. Although the primary trigger of PAH remains unknown, oxidative stress and inflammation have been shown to play a key role in the development and progression of vascular remodeling. These factors are known to increase DNA damage that might favor the emergence of the proliferative and apoptosis-resistant phenotype observed in PAH vascular cells. High levels of DNA damage were reported to occur in PAH lungs and remodeled arteries as well as in animal models of PH. Moreover, recent studies have demonstrated that impaired DNA-response mechanisms may lead to an increased mutagen sensitivity in PAH patients. Finally, PAH was linked with decreased breast cancer 1 protein (BRCA1) and DNA topoisomerase 2-binding protein 1 (TopBP1) expression, both involved in maintaining genome integrity. This review aims to provide an overview of recent evidence of DNA damage and DNA repair deficiency and their implication in PAH pathogenesis.

The study of the relation of DNA repair pathway genes SNPs and the sensitivity to radiotherapy and chemotherapy of NSCLC

To analyze the relation between SNPs in DNA repair pathway-related genes and sensitivity of tumor radio-chemotherapy, 26 SNPs in 20 DNA repair genes were genotyped on 176 patients of NSCLC undertaking radio-chemotherapy treatment. In squamous cell carcinoma (SCC), as the rs2228000, rs2228001 (XPC), rs2273953 (TP73), rs2279744 (MDM2), rs2299939 (PTEN) and rs8178085, rs12334811 (DNA-PKcs) affected the sensitivity to chemotherapy, so did the rs8178085, rs12334811 to radiotherapy. Moreover rs344781, rs2273953 and rs12334811 were related with the survival time of SCC. In general, the “good” genotype GG (rs12334811) showed greater efficacy of radio-chemotherapy and MSF (24 months) on SCC. In adenocarcinoma, as the rs2699887 (PIK3), rs12334811 (DNA-PKcs) influenced the sensitivity to chemotherapy, so did the rs2299939, rs2735343 (PTEN) to radiotherapy. And rs402710, rs80270, rs2279744 and rs2909430 impacted the survival time of the adenocarcinoma patients. Both GG (rs2279744) and AG (rs2909430) showed a shorter survival time (MFS = 6). Additionally, some SNPs such as rs2228000, rs2228001 and rs344781 were found to regulate the expression of DNA repair pathway genes through eQTLs dataset analysis. These results indicate that SNPs in DNA repair pathway genes might regulate the expression and affect the DNA damage repair, and thereby impact the efficacy of radio-chemotherapy and the survival time of NSCLC.

Survivin protein expression is involved in the progression of non-small cell lung cancer in Asians: a meta-analysis

Background

Surviving expression might serve as a prognostic biomarker predicting the clinical outcome of non-small cell lung cancer (NSCLC). The study was conducted to explore the potential correlation of survivin protein expression with NSCLC and its clinicopathologic characteristics.

Methods

PubMed, Medline, Cochrane Library, CNKI and Wanfang database were searched through January 2016 with a set of inclusion and exclusion criteria. Data was extracted from these articles and all statistical analysis was conducted by using Stata 12.0.

Results

A total of 28 literatures (14 studies in Chinese and 14 studies in English) were enrolled in this meta-analysis, including 3206 NSCLC patients and 816 normal controls. The result of meta-analysis demonstrated a significant difference of survivin positive expression between NSCLC patients and normal controls (RR = 7.16, 95 % CI = 4.63-11.07, P < 0.001). To investigate the relationship of survivin expression and clinicopathologic characteristics, we performed a meta-analysis in NSCLC patients. Our results indicates survivin expression was associated with histological differentiation, tumor-node-metastasis (TNM) stage and lymph node metastasis (LNM) (RR = 0.80, 95 % CI = 0.73-0.87, P < 0.001; RR = 0.75, 95 % CI = 0.67-0.84, P < 0.001; RR = 1.14, 95 % CI = 1.01-1.29, P = 0.035, respectively), but not pathological type and tumor size. (RR = 1.00, 95 % CI = 0.93-1.07, P = 0.983; RR = 0.95, 95 % CI = 0.86-1.05, P = 0.336, respectively).

Conclusion

Higher expression of survivin in NSCLC patients was found when compared to normal controls. Survivin expression was associated with the clinicopathologic characteristics of NSCLC and may serves as an important biomarker for NSCLC progression.

NSCLC cells demonstrate differential mode of cell death in response to the combined treatment of radiation and a DNA-PKcs inhibitor

The current standard of care for lung cancer consists of concurrent chemotherapy and radiation. Several studies have shown that the DNA-PKcs inhibitor NU7441 is a highly potent radiosensitizer, however, the mechanism of NU7441's anti-proliferation effect has not been fully elucidated. In this study, the combined effect of NU7441 and ionizing radiation (IR) in a panel of non-small cell lung cancer cell lines (A549, H460 and H1299) has been investigated. We found that NU7441 significantly enhances the effect of IR in all cell lines. The notable findings in response to this combined treatment are (i) prolonged delay in IR-induced DNA DSB repair, (ii) induced robust G2/M checkpoint, (iii) increased aberrant mitosis followed by mitotic catastrophe specifically in H1299, (iv) dramatically induced autophagy in A549 and (v) IR-induced senescence specifically in H460. H1299 cells show greater G2 checkpoint adaptation after combined treatment, which can be attributed to higher expression level of Plk1 compared to A549 and H460. The enhanced autophagy after NU7441 treatment in A549 is possibly due to the higher endogenous expression of pS6K compared to H1299 and H460 cells. In conclusion, choice of cell death pathway is dependent on the mutation status and other genetic factors of the cells treated.

Prognostic implications of survivin and lung resistance protein in advanced non-small cell lung cancer treated with platinum-based chemotherapy

Platinum-based chemotherapy is the first-line treatment for non-small cell lung cancer (NSCLC), but the chemotherapy often results in the development of chemoresistance. The present study aimed to explore the prognostic implications of survivin and lung resistance protein (LRP) in advanced NSCLC treated with platinum-based chemotherapy. Tumor samples were collected from 61 hospitalized patients with stage IIIB-IV NSCLC that underwent platinum-based chemotherapy. All patient samples were collected in the Oncology Department of the Third Affiliated Hospital of Guangxi Medical University between January 2006 and January 2011. Cytoplasmic survivin and LRP expression were evaluated using immunohistochemistry. The expression of LRP and survivin reached 77% (47/61) and 76% (45/61), respectively. Positive expression of survivin was associated with a lower median progression-free survival (PFS) time (4 vs. 9 months; P=0.038) and a lower median overall survival (OS) time compared with the absence of survivin expression (9 vs. 16 months; P=0.039). Patients with LRP and survivin expression (n=41) demonstrated a median PFS time of 4 months. However, patients with either LRP or survivin expression (n=10) demonstrated a median PFS time of 8 months, which is similar to the median PFS time of the 10 patients with no expression of LRP and survivin (9 months; P=0.022). Either the expression of survivin or the combined expression of LRP and survivin is associated with a poor prognosis in advanced NSCLC treated with platinum-based chemotherapy.

MicroR-545 enhanced radiosensitivity via suppressing Ku70 expression in Lewis lung carcinoma xenograft model

Objective

Radiotherapy is an important therapeutic method for lung cancer. However, in clinical situations, cellular resistance to radiotherapy is a significant component of tumor treatment failure. Thus, clarification in cellular mechanism underlying radiosensitivity of cancer cell is urgently needed. In this study, we established a radiation model of Lewis lung carcinoma in C57BL/6 mice and investigated the possible signaling molecule involved in this process.

Methods

C57BL/6 mice were subcutaneously transplanted with Lewis lung carcinoma cells and locally irradiated followed by measurement in tumor volume. Levels of miR-545 and Ku70 mRNA expression were determined by using Quantitative Real-Time PCR. Expression of Ku70 was determined by using western blot assay. Cell viability was analyzed by MTT assay. Cell apoptosis was examined by using TUNEL assay.

Results

In mice bearing Lewis lung carcinoma tumor, local radiotherapy suppressed tumor growth as well as enhanced expression of miR-545 and downregulated Ku70 level. Inhibition of miR-545 expression reduced radiosensitivity of Lewis tumor. In vitro Lewis lung carcinoma cells experiment, we observed that miR-545 regulated Ku70 expression by targeting Ku70 3′UTR and this process was involved in radiotherapy. This was demonstrated by result of cell proliferation assay in which irradiation reduced apoptosis of cells was mediated by miR-545 inactivation which was reversed by Ku70 silence.

Conclusion

miR-545 increased radiosensitivity of Lewis lung carcinoma via inhibiting Ku70 expression.