Impact of ERCC1 expression on treatment outcome in small-cell lung cancer patients treated with platinum-based chemotherapy

Gene Expression Levels of the Prolyl Hydroxylase Domain Proteins PHD1 and PHD2 but Not PHD3 Are Decreased in Primary Tumours and Correlate with Poor Prognosis of Patients with Surgically Resected Non-Small-Cell Lung Cancer

Simple Summary

Hypoxia correlates with poor prognosis in several cancer types, including lung cancer. Prolyl hydroxylase domain proteins (PHDs) belong to an evolutionarily conserved superfamily of dioxygenases that play a role in cell oxygen sensing and homeostasis. In this study, we evaluated PHD1, PHD2 and PHD3 mRNA expression in 60 NSCLC tumours and compared it to that in normal lungs and evaluated the prognostic significance of these differences for distinguishing the survival of NSCLC patients treated with radical surgery. Our results showed that the mRNA expression PHD1 and PHD2 in NSCLC primary tumours was decreased, which correlated with larger tumour size and poor prognosis of patients. PHD1 also showed borderline independent prognostic value in multivariate analysis. In contrast, we found no associations between PHD3 expression and any of the observed parameters. Our results suggest that loss of PHD1 and PHD2 expression is associated with the development and progression of NSCLC, whereas PHD1 could be further assessed as a prognostic marker in NSCLC.

Abstract

Background: Hypoxia correlates with poor prognosis in several cancer types, including lung cancer. Prolyl hydroxylase domain proteins (PHDs) play a role in cell oxygen sensing, negatively regulating the hypoxia-inducible factor (HIF) pathway. Our study aim was to evaluate PHD1, PHD2 and PHD3 mRNA expression levels in primary tumours and normal lungs of non-small-cell lung cancer (NSCLC) patients and to correlate it with selected regulators of HIF signalling, with clinicopathological characteristics and overall survival (OS). Methods: Tumour tissue samples were obtained from 60 patients with surgically resected NSCLC who were treated with radical surgery. In 22 out of 60 cases, matching morphologically normal lung tissue was obtained. PHD1, PHD2 and PHD3 mRNA expressions were measured using RT-qPCR. Results: The PHD1 and PHD2 mRNA levels in primary tumours were significantly decreased compared to those in normal lungs (both p < 0.0001). PHD1 and PHD2 expression in tumours was positively correlated (r_s = 0.82; p < 0.0001) and correlated well with HIF pathway downstream genes HIF1A, PKM2 and PDK1. Decreased PHD1 and PHD2 were associated with larger tumour size, higher tumour stage (PHD1 only) and squamous cell carcinoma. Patients with low PHD1 and patients with low PHD2 expression had shorter OS than patients with high PHD1 (p = 0.02) and PHD2 expression (p = 0.01). PHD1 showed borderline independent prognostic values in multivariate analysis (p = 0.06). In contrast, we found no associations between PHD3 expression and any of the observed parameters. Conclusions: Our results show that reduced expression of PHD1 and PHD2 is associated with the development and progression of NSCLC. PHD1 could be further assessed as a prognostic marker in NSCLC.

Interplay between BRCA1 and GADD45A and Its Potential for Nucleotide Excision Repair in Breast Cancer Pathogenesis

A fraction of breast cancer cases are associated with mutations in the BRCA1 (BRCA1 DNA repair associated, breast cancer type 1 susceptibility protein) gene, whose mutated product may disrupt the repair of DNA double-strand breaks as BRCA1 is directly involved in the homologous recombination repair of such DNA damage. However, BRCA1 can stimulate nucleotide excision repair (NER), the most versatile system of DNA repair processing a broad spectrum of substrates and playing an important role in the maintenance of genome stability. NER removes carcinogenic adducts of diol-epoxy derivatives of benzo[α]pyrene that may play a role in breast cancer pathogenesis as their accumulation is observed in breast cancer patients. NER deficiency was postulated to be intrinsic in stage I of sporadic breast cancer. BRCA1 also interacts with GADD45A (growth arrest and DNA damage-inducible protein GADD45 alpha) that may target NER machinery to actively demethylate genome sites in order to change the expression of genes that may be important in breast cancer. Therefore, the interaction between BRCA1 and GADD45 may play a role in breast cancer pathogenesis through the stimulation of NER, increasing the genomic stability, removing carcinogenic adducts, and the local active demethylation of genes important for cancer transformation.

ERCC1_202 Is A Prognostic Biomarker in Advanced Stage Non-Small Cell Lung Cancer Patients Treated with Platinum-Based Chemotherapy

Purpose: To develop a qPCR method to examine the 202 isoform of excision repair cross-complementation group 1 (ERCC1_202) and to evaluate its clinical utility as a predictive biomarker for platinum-based chemotherapy in non-small cell lung cancer (NSCLC). Methods: The relative complementary DNA (cDNA) quantification for ERCC1_202 was conducted using a fluorescence-based, real-time detection method and β-actin was used as a reference gene. Results: A strong correlation was observed between ERCC1_202 mRNA and ERCC1 mRNA levels in NSCLC cells (P < 0.001). 28 patients completed this research. Our results implied that as ERCC1_202 levels increased, the risk of progression (HR = 4.296, P = 0.011) and death (HR = 6.503, P = 0.001) increased. At multivariate analysis, high expression of ERCC1_202 was shown to be an independent predictive factor for time to progression (P = 0.047), and progression-free survival (P = 0.014). However, the high expression of ERCC1_202 was not an independent predictive factor for response (P = 0.324). Conclusions: This study suggests that the efficacy of platinum-based chemotherapy can be improved when customized according to the expression of ERCC1_202.

Chemosensitizing effect of shRNA-mediated ERCC1 silencing on a Xuanwei lung adenocarcinoma cell line and its clinical significance

Lung cancer is a common fatal malignancy in both men and women. Xuanwei, Yunnan has the highest incidence of lung cancer in China. The area has a specific risk factor in the domestic combustion of bituminous coal, and lung cancer patients from this area tend to be resistant to platinum-based treatments. However, little is known about the mechanism of platinum resistance in patients from Xuanwei. Herein, we used lentiviral infection with shRNA to silence expression of the DNA repair enzyme ERCC1 in XWLC05 both in its RNA and protein expression level, a lung adenoma cell line derived from a patient from Xuanwei. ERCC1 expression in this cell line is high and contributes to its resistance to cisplatin. Suppression of ERCC1 decreased XWLC05 proliferation in vitro (IC50 of cisplatin 1.34 µM for shRNA-infected cells vs. 4.54 µM for control cells) and increased the apoptotic rate after treatment with cisplatin (81.2% shRNA cells vs. 58% control cells, P<0.05). Progression-free survival was longer in ERCC1-negative lung adenoma patients than those with high ERCC1 levels (30 vs. 11 months, P<0.0001). ERCC1 expression was identified as a prognostic marker for overall survival in the patient cohort with operable lesions. Taken together, our data identify ERCC1 as a disease marker in lung adenoma patients from Xuanwei and confirm the significance of resection for the subsequent effect of platinum treatment in these patients. Additional studies are needed to determine the mechanism of ERCC1-induced platinum resistance in lung adenoma patients from Xuanwei.

The prognostic value of whole blood SOX2, NANOG and OCT4 mRNA expression in advanced small-cell lung cancer

BACKGROUND

The data on expression and clinical impact of cancer stem cell markers SOX2, NANOG and OCT4 in lung cancer is still lacking. The aim of our study was to compare SOX2, NANOG and OCT4 mRNA expression levels in whole blood between advanced small-cell lung cancer (SCLC) patients and healthy controls, and to correlate mRNA expression with progression-free survival (PFS) after first-line chemotherapy and overall survival (OS) in advanced SCLC patients.

PATIENTS AND METHODS

50 advanced SCLC patients treated with standard chemotherapy and followed at University Clinic Golnik, Slovenia, between 2009 and 2013 were prospectively included. SOX2, NANOG and OCT4 mRNA expression levels were determined using TaqMan qPCR in whole blood collected prior to chemotherapy. Whole blood of 34 matched healthy individuals with no cancerous disease was also tested.

RESULTS

SOX2 mRNA expression was significantly higher in whole blood of SCLC patients compared to healthy controls (p = 0.006). Significant correlation between SOX2 mRNA expression levels and the number of distant metastatic sites was established (p = 0.027). In survival analysis, patients with high SOX2 expression had shorter OS (p = 0.017) and PFS (p = 0.046). In multivariate Cox analysis, an independent value of high SOX2 expression for shorter OS (p = 0.002), but not PFS was confirmed. No significant differences were observed for NANOG or OCT4 expression levels when comparing SCLC patients and healthy controls neither when analysing survival outcomes in SCLC patients.

CONCLUSIONS

SOX2 mRNA expression in whole blood might be a promising non-invasive marker for molecular screening of SCLC and important prognostic marker in advanced chemotherapy-treated SCLC patients, altogether indicating important role of cancer stem-like cell (CSC) regulators in cancer spread. Further evaluation of SOX2 as a possible screening/prognostic marker and a therapeutic target of SCLC is warranted.

Therapeutic biomarkers in lung neuroendocrine neoplasia

The well-known classification of neuroendocrine neoplasms of the lung into four major subtypes (including typical and atypical carcinoids and small- and large-cell neuroendocrine carcinomas) has a proven prognostic validity but only partially helps to predict the response to specific therapies. Therapeutic biomarkers are incompletely known and include morphological, immunophenotypic, and molecular markers. Morphology alone has no specific predictive role, nor has any immunophenotypic marker been proven to bear predictive implications. Ki67 is a relevant prognostic marker and can indirectly predict response to chemotherapy, when levels are extremely high in high-grade neuroendocrine (NE) carcinomas. The expression of somatostatin receptors, especially of the type 2A, has been shown to predict response to somatostatin analog treatments, paralleling the information derived from octreotide scintigraphy. mTOR pathway is targeted by specific inhibitors, but the exact cellular molecules predicting response are still to be defined. It seems that high levels of phosphorylated forms of mTOR and of its downstream factor S6K are associated to a better response to rapalogs in experimental models. Data from gene expression profiling and mutational analyses are currently emerging, providing a more detailed map of different molecular activation pathways, potentially leading to a more accurate molecular classification of lung NE tumors as well as to the discovery of new therapeutic targets. The combination of mutational profiles with those of upregulated or downregulated genes also by gene gains or losses may ultimately provide a better characterization of NE tumor histological types in terms of response to specific chemotherapy or biotherapy.

The prognostic value of excision repair cross-complementation group 1 (ERCC1) in patients with small cell lung cancer (SCLC) receiving platinum-based chemotherapy: evidence from meta-analysis

Recently, the correlation between the efficacy of platinum-based chemotherapy and ERCC1 expression in patients with SCLC has attracted wide-spread attention, and a lot of investigations have been conducted, whereas conflicting results were presented. Therefore, we performed the present meta-analysis of eligible studies to derive a more precise evaluation of the association between ERCC1 expression and the clinical outcome in SCLC patients receiving platinum-based chemotherapy. A literature search for relevant studies was conducted in the electronic databases of PubMed, EMBASE and Web of Science. The inclusive criteria were SCLC patients treated by platinum-based chemotherapy, and evaluated the relationship between ERCC1 expression and the clinical outcomes [including overall response rate (ORR), overall survival (OS) or progression-free survival (PFS)]. Odds ratio (OR) or hazard ratio (HR) with 95% confidence interval (CI) was calculated to assess the risk. A total of nine studies including 1129 patients were included in final analysis. Our analysis indicated that positive/high ERCC1 expression was associated with unfavorable OS (HR = 1.18, 95%CI = 1.02–1.37) and PFS (HR = 1.46, 95%CI = 1.14–1.88). Subgroup analysis according to disease stage suggested the significant relationship was found in limited stage (LS-SCLC), but not in extensive stage (ES-SCLC). However, no significant association was found between ERCC1 expression and ORR. Our analysis suggested ERCC1 expression may be a prognostic factor in SCLC patients receiving platinum-based chemotherapy, especially for LS-SCLC.

The role of DNA repair pathways in cisplatin resistant lung cancer

Platinum chemotherapeutic agents such as cisplatin are currently used in the treatment of various malignancies such as lung cancer. However, their efficacy is significantly hindered by the development of resistance during treatment. While a number of factors have been reported that contribute to the onset of this resistance phenotype, alterations in the DNA repair capacity of damaged cells is now recognised as an important factor in mediating this phenomenon. The mode of action of cisplatin has been linked to its ability to crosslink purine bases on the DNA, thereby interfering with DNA repair mechanisms and inducing DNA damage. Following DNA damage, cells respond by activating a DNA-damage response that either leads to repair of the lesion by the cell thereby promoting resistance to the drug, or cell death via activation of the apoptotic response. Therefore, DNA repair is a vital target to improving cancer therapy and reduce the resistance of tumour cells to DNA damaging agents currently used in the treatment of cancer patients. To date, despite the numerous findings that differential expression of components of the various DNA repair pathways correlate with response to cisplatin, translation of such findings in the clinical setting are still warranted. The identification of alterations in specific proteins and pathways that contribute to these unique DNA repair pathways in cisplatin resistant cancer cells may potentially lead to a renewed interest in the development of rational novel therapies for cisplatin resistant cancers, in particular, lung cancer.

Prognostic significance of BRCA1, ERCC1, RRM1, and RRM2 in patients with advanced non-small cell lung cancer receiving chemotherapy

The aim of this study was to examine the prognostic value of breast cancer susceptibility gene 1 (BRCA1), excision repair cross-complementation 1 (ERCC1), ribonucleotide reductase subunit M1 (RRM1), and ribonucleotide reductase subunit M2 (RRM2) in patients with advanced non-small cell lung cancer (NSCLC) who received platinum-based chemotherapy. A total of 214 patients with histologically or cytologically confirmed advanced NSCLC were enrolled in this study. The relative complementary DNA (cDNA) quantification for BRCA1, ERCC1, RRM1, and RRM2 was conducted using a fluorescence-based, real-time detection method, and β-actin was used as a reference gene. A strong correlation was observed between ERCC1 and RRM1 messenger RNA (mRNA) levels (P = 0.0385). There were inverse significant correlations between BRCA1 and ERCC1 (P < 0.0001) or RRM1 (P < 0.0001) mRNA levels. As BRCA1 levels increased, the probability of response increased (odds ratio [OR] = 0.49; P < 0.001) and the risk of progression (hazard ratio [HR] = 1.52; P = 0.034) and death (HR = 1.45; P = 0.024) decreased. As ERCC1, RRM1, and RRM2 levels increased, the probability of response decreased (ERCC1, OR = 0.42, P < 0.001; RRM1, OR = 0.85, P = 0.083; RRM2, OR = 0.42, P = 0.005) and the risk of progression (ERCC1, HR = 1.59, P = 0.002; RRM1, HR = 1.48, P = 0.039; RRM2, HR = 1.49, P = 0.041) and death (ERCC1, HR = 1.62, P = 0.008; RRM1, HR = 1.52, P = 0.023; RRM2, HR = 1.48, P = 0.017) increased. At multivariate analysis, low expression of ERCC1 was shown to be an independent predictive factor for response to chemotherapy (P = 0.018), time to progression (P = 0.025), and overall survival (P = 0.038). Furthermore, concomitant low expression levels of ERCC1, RRM1, and RRM2 and the high expression level of BRCA1 were predictive of a better outcome (P = 0.014). This study suggests that the efficacy of platinum-based chemotherapy can be improved when customized according to the mRNA expression of BRCA1, ERCC1, RRM1, and RRM2.

ERCC1 and BRCA1 mRNA expression predicts the clinical outcome of non-small cell lung cancer receiving platinum-based chemotherapy

Objective: We conducted a perspective study to investigate the association between mRNA expression quantities of ERCC1, BRCA1, RRM1 and RRM2 and response to chemotherapy and clinical outcome of advance Non-Small Cell Lung Cancer.(NSCLC).

Methods: Two hundred eight patients who were diagnosed as advanced stage NSCLC were included in our study. A fluorescence-based and real-time detection method was used to determine the relative cDNA quantification for ERCC1, BRCA1, RRM1 and RRM2, and β-actin was used as the reference gene.

Results: The median expression levels of ERCC1, BRCA1, RRM1 and RRM2 mRNA were 0.67±0.17, 0.095±0.012, 0.24±0.17 and 2.45±0.32, respectively. Our study found that the low ERCC1 (OR=1.82, 95% CI=1.01-3.20) and Low BRCA1 (OR=2.53, 95%CI=1.38-4.64) mRNA expression was more likely to response to chemotherapy when compared with high expression, respectively. Multivariate Cox regression analysis indicated that patients with low mRNA expression of ERCC1 and BRCA1 attained 0.43 (OR=0.43, 95%CI=0.27-0.89) and 0.37 (OR=0.37, 95%CI=0.22-0.66) fold risk of death from NSCLC. However, we found RMM1 and RRM2 mRNA expression could not influence the response to chemotherapy and clinical outcome of NSCLC.

Conclusion: ERCC1 and BRCA1 mRNA expression could be important predictive markers for individualized platinum-based chemotherapy for NSCLC patients.

Expression levels of ERCC1 and RRM1 mRNA and clinical outcome of advanced non-small cell lung cancer

Objective: We conducted a study to understand the genetic effect of ERCC1 and RRM1 on the chemotherapy response and clinical outcome of Non-Small Cell Lung Cancer (NSCLC).

Methods: The relative cDNA quantification for ERCC1 and RRM1 was conducted using a fluorescence-based real-time detection method among 294 NSCLC patients.

Results: Compared with the internal reference gene β-action, the median levels of ERCC1 and RRM1 expression were 2.43×10^-2 and 0.11×10^-2, respectively. Our study showed response to platinum-containing regimen chemotherapy was high in those with high ERCC1 expression, and the OR (95% CI) were 1.73(1.06-2.81). An apparently high response to chemotherapy was decreased when patients were carrying both high expression of ERCC1 and RRM1, with OR (95% CI) of 2.57(1.21-4.90). Patients with high expression of ERCC1 were associated with a longer OS by multivariate Cox proportional hazards model. Moreover, those carrying both high levels of ERCC1 and RRM1 were seem to have a longer OS when compared with those with low expression (HR=0.31, 95% CI=0.13-0.62 for OS).

Conclusion: This observation could be used in personalized chemotherapy, increase the response rate and prolonged survival time, and could encourage to explore the predictive value of other genes.

Markers of response to platinum-based chemotherapy in lung cancer

SUMMARY Non-small-cell lung cancer (NSCLC) is the most common cause of cancer-related deaths among men and women worldwide. Despite the development of molecular targeted therapies, platinum-based combination chemotherapy remains the most effective systemic chemotherapy for NSCLC patients. Unfortunately, the outcomes of platinum-based therapies, in particular those containing cisplatin, have reached a plateau due to the development of both intrinsic and acquired resistance. While significant variations in response to platinum-based chemotherapeutic regimens exist, defining molecular features that may determine resistance or response to chemotherapy is critical. This review will focus on some of the emerging biomarkers that are predictive of response to such treatments that may offer potential in the future management of NSCLC patients.