Excision Repair Cross-Complementation Group 1 Enzyme as a Molecular Determinant of Responsiveness to Platinum-Based Chemotherapy for non Small-Cell Lung Cancer

Understanding Cancer's Defense against Topoisomerase-Active Drugs: A Comprehensive Review

In recent years, the emergence of cancer drug resistance has been one of the crucial tumor hallmarks that are supported by the level of genetic heterogeneity and complexities at cellular levels. Oxidative stress, immune evasion, metabolic reprogramming, overexpression of ABC transporters, and stemness are among the several key contributing molecular and cellular response mechanisms. Topo-active drugs, e.g., doxorubicin and topotecan, are clinically active and are utilized extensively against a wide variety of human tumors and often result in the development of resistance and failure to therapy. Thus, there is an urgent need for an incremental and comprehensive understanding of mechanisms of cancer drug resistance specifically in the context of topo-active drugs. This review delves into the intricate mechanistic aspects of these intracellular and extracellular topo-active drug resistance mechanisms and explores the use of potential combinatorial approaches by utilizing various topo-active drugs and inhibitors of pathways involved in drug resistance. We believe that this review will help guide basic scientists, pre-clinicians, clinicians, and policymakers toward holistic and interdisciplinary strategies that transcend resistance, renewing optimism in the ongoing battle against cancer.

Pharmacological Treatment of Patients with Metastatic, Recurrent or Persistent Cervical Cancer Not Amenable by Surgery or Radiotherapy: State of Art and Perspectives of Clinical Research

Cervical cancer patients with distant or loco-regional recurrences not amenable by surgery or radiotherapy have limited treatment options, and their 5-year overall survival (OS) rates range from 5% to 16%. The purpose of this paper is to assess the results obtained with chemotherapy and biological agents in this clinical setting. Several phase II trials of different cisplatin (CDDP)-based doublets and a phase III randomized trial showing a trend in response rate, progression-free survival, and OS in favor of CDDP + paclitaxel (PTX) compared with other CDDP-based doublets have been reviewed. The factors predictive of response to chemotherapy as well as the benefits and risks of the addition of bevacizumab to CDDP + PTX have been analyzed. The FDA has recently approved pembrolizumab for patients with recurrent or metastatic cervical cancer in progression on or after chemotherapy whose tumors were PD-L1 positive. Interesting perspectives of clinical research are represented by the use of immune checkpoint inhibitors alone or in addition to chemotherapy, whereas PARP inhibitors and PI3K inhibitors are still at the basic research phase, but promising.

Emerging role of phytochemicals in targeting predictive, prognostic, and diagnostic biomarkers of lung cancer

Lung-cancer is the foremost cause of cancer in humans worldwide, of which 80-85% cases are composed of non-small cell lung carcinoma. All treatment decisions depend on the pattern of biomarkers selection to enhance the response to the targeted therapies. Although advanced treatments are available for lung-cancer, the disease treatment remains not adequate. There are several synthetic chemotherapeutic agents available for the treatment of lung cancer. However, due to their toxic effect, survival rate is still 15-18%. Besides, medicinal plants are a huge reservoir of natural products that provide protective effects against lung cancer. Likewise, successful studies of potential phytochemicals in targeting lung-cancer biomarkers have created a novel paradigm for the discovery of potent drugs against lung-cancer. Hence, to defeat severe toxicity and resistance towards the synthetic drugs, detailed studies are required regarding the available phytochemicals and targets responsible for the treatment of lung-cancer. The present review provides a comprehensive information about the lung-cancer biomarkers under the classification of predictive, prognostic, and diagnostic type. Moreover, it discusses and enlists the phytochemicals with mode of action against different biomarkers, effective doses in in vitro, in vivo, and clinical studies, the limitations associated with usage of phytochemicals as a drug to prevent/cure lung-cancer and the latest techniques employed to overcome such issues.

ERCC1 expression status predicts the response and survival of patients with metastatic or recurrent cervical cancer treated via platinum-based chemotherapy

The deoxyribonucleic acid (DNA) repair gene encoding the excision-repair cross-complementation group 1 (ERCC1) protein is known to predict the response to platinum-based chemotherapy. Our aim was to explore whether ERCC1 expression predicted tumor response and survival in patients with recurrent or metastatic cervical cancer treated via platinum-based chemotherapy. We analyzed 32 such patients. ERCC1 expression was assessed immunohistochemically in pretreatment biopsy samples. Of the 32 patients, 13 (40.6%) were ERCC1 high. ERCC1-low patients exhibited a significantly higher response rate (73.7%) than did others (15.4%). The median progression-free survival differed significantly by ERCC1 status, being 135 days in ERCC1-high and 242 days in ERCC1-low patients (hazard ratio, 2.428; 95% confidence interval, 1.145-5.148, P = .032). Overall survival was significantly longer in ERCC1-low (617 days) than in ERCC1-high (320 days) patients (hazard ratio, 2.322; 95% confidence interval, 1.051-5.29; P = .037). Thus, pretreatment ERCC1 expression status can be used to predict tumor response and survival of patients with recurrent or metastatic uterine cervical cancer receiving platinum-based chemotherapy.

Cisplatin resistance in non-small cell lung cancer cells is associated with an abrogation of cisplatin-induced G2/M cell cycle arrest

The efficacy of cisplatin-based chemotherapy in cancer is limited by the occurrence of innate and acquired drug resistance. In order to better understand the mechanisms underlying acquired cisplatin resistance, we have compared the adenocarcinoma-derived non-small cell lung cancer (NSCLC) cell line A549 and its cisplatin-resistant sub-line A549^rCDDP²⁰⁰⁰ with regard to cisplatin resistance mechanisms including cellular platinum accumulation, DNA-adduct formation, cell cycle alterations, apoptosis induction and activation of key players of DNA damage response. In A549^rCDDP²⁰⁰⁰ cells, a cisplatin-induced G₂/M cell cycle arrest was lacking and apoptosis was reduced compared to A549 cells, although equitoxic cisplatin concentrations resulted in comparable platinum-DNA adduct levels. These differences were accompanied by changes in the expression of proteins involved in DNA damage response. In A549 cells, cisplatin exposure led to a significantly higher expression of genes coding for proteins mediating G₂/M arrest and apoptosis (mouse double minute 2 homolog (MDM2), xeroderma pigmentosum complementation group C (XPC), stress inducible protein (SIP) and p21) compared to resistant cells. This was underlined by significantly higher protein levels of phosphorylated Ataxia telangiectasia mutated (pAtm) and p53 in A549 cells compared to their respective untreated control. The results were compiled in a preliminary model of resistance-associated signaling alterations. In conclusion, these findings suggest that acquired resistance of NSCLC cells against cisplatin is the consequence of altered signaling leading to reduced G₂/M cell cycle arrest and apoptosis.

Prognostic and predictive factors in patients with metastatic or recurrent cervical cancer treated with platinum-based chemotherapy

BACKGROUND

Recognizing resistance or susceptibility to the current standard cisplatin and paclitaxel treatment could improve therapeutic outcomes of metastatic or recurrent cervical cancer.

METHODS

Forty-five tissue samples from patients participating in a phase II trial of cisplatin and ifosfamide, with or without paclitaxel were collected for retrograde analysis. Immunohistochemistry and genotyping was performed to test ERCC1, III β-tubulin, COX-2, CD4, CD8 and ERCC1 (C8092A and N118 N) and MDR1 (C3435T and G2677 T) gene polymorphisms, as possible predictive and prognostic markers. Results were statistically analyzed and correlated with patient characteristics and outcomes.

RESULTS

Patients with higher levels of ERCC1 expression had shorter PFS and OS than patients with low ERCC1 expression (mPFS:5.1 vs 10.2 months, p = 0.027; mOS:10.5 vs. 21.4 months, p = 0.006). Patients with TT in the site of ERCC1 N118 N and GT in the site of MDR1 G2677 T polymorphisms had significantly longer PFS (p = 0.006 and p = 0.027 respectively). ERCC1 expression and the ERCC1 N118 N polymorphism remained independent predictors of PFS. Interestingly, high III beta tubulin expression was associated with chemotherapy resistance and fewer responses [5/20 (25%)] compared to lower III β-tubulin expression [15/23 (65.2%)] (p = 0.008). Finally, ΙΙΙ β-tubulin levels and chemotherapy regimen were independent predictors of response to treatment.

CONCLUSIONS

ERCC1 expression proved to be a significant prognostic factor for survival in our metastatic or recurrent cervical cancer population treated with cisplatin based chemotherapy. ERCC1 N118 N and MDR1 G2677 T polymorphism also proved of prognostic significance for disease progression, while overexpression of III β-tubulin was positively correlated with chemotherapy resistance.

ERCC1 Expression in Non-Small Cell Lung and Esophageal Cancer

OBJECTIVE

"Excision Repair Cross-Complementation Group 1" (ERCC1) enzyme is a vitally important basic protein required for DNA repair. Recent studies suggest that ERCC1 is involved in resistance to antracycline-based chemotherapy regimens. In this study, we aimed to analyze ERCC1 expression in lung and esophageal cancer patients. We also aimed to investigate the possible correlation between the ERCC1 expression levels and patient demographic information.

MATERIALS AND METHODS

Twenty esophageal and 20 non-small cell lung cancer (NSCLC) patients diagnosed between December 2009 and December 2010, via either endoscopic, bronchoscopic or tru-cut biopsy, were included in this study. The ERCC1 expression levels were analyzed by the reverse transcriptase-polymerase chain reaction (RTPCR) method in RNA samples extracted from pathological biopsy specimens. The patient demographic information was also recorded.

RESULTS

There was no significant correlation between the ERCC1 expression level and demographic parameters, including the tumor, node, metastatis (TNM) staging, World Health Organization (WHO) grading, age, gender, hemoglobin level and albumin level, in the patient groups. The mean ERCC1 expression levels in the NSCLC and esophageal cancer patients were 0.71±0.85 and 0.62±0.78, respectively. The ERCC1 expression level was elevated in 15% of each patient group.

CONCLUSION

Analysis of the ERCC1 expression in NSCLC and esophageal cancer patients prior to chemotherapy would be useful for personalized chemotherapy regimens and would provide more accurate prognostic information for the patient.

Drug resistance and its significance for treatment decisions in non-small-cell lung cancer

Non-small-cell lung cancer (nsclc) constitutes about 85% of all lung cancers. Approximately 50% of patients diagnosed with nsclc present with advanced disease (stage iii or iv) that is not amenable to curative treatment. The number of patients with stage iiib or iv disease who are alive at 1 year after diagnosis has increased from 10% in the untreated population in the early 1980s to 50% in patients with a good performance status receiving treatment today. However, those statistics remain dismal, and the two dominant reasons are the large number of patients diagnosed with advanced-stage disease and the observed primary or secondary resistance to current therapies. The present article addresses the question of drug resistance in lung cancer, focusing on subjects that are currently topical and under intense scrutiny.

ERCC1 Expression Analysis to Guide Therapy in Non-Small Cell Lung Cancer

Worldwide, lung cancer accounts for approximately 1 million deaths each year, making it the most common cause of cancer-related mortality. Non-small cell lung cancer (NSCLC) accounts for approximately 85% of lung cancer cases and is often associated with a relatively poor prognosis. The majority of NSCLC patients present with advanced disease and have an average 5-year survival rate of 5%. Currently, the standard of care for NSCLC includes treatment with a platinum-based chemotherapy regimen. However, not all patients benefit equally from such treatment. Therefore, recent pharmacogenomic studies have been performed in order to identify specific biomarkers that may allow for patient-tailored treatment strategies. One such biomarker is expression of the excision repair cross-complementation group 1 protein, ERCC1.