Radiation sensitivities of 31 human oesophageal squamous cell carcinoma cell lines

Effects of JWA, XRCC1 and BRCA1 mRNA expression on molecular staging for personalized therapy in patients with advanced esophageal squamous cell carcinoma

BACKGROUND

DNA damage repair genes JWA, XRCC1 and BRCA1 were associated with clinical outcomes and could convert the response to the cisplatin-based therapy in some carcinomas. The synergistic effects of JWA, XRCC1 and BRCA1 mRNA expression on personalized therapy remain unknown in advanced esophageal squamous cell carcinoma (ESCC).

METHODS

We employed quantitative real-time polymerase chain reaction (qPCR) to determine the expression of JWA, XRCC1 and BRCA1 mRNA in paraffin-embedded specimen from 172 patients with advanced ESCC who underwent the first-line cisplatin-or docetaxel-based treatments.

RESULTS

High JWA or XRCC1mRNA expression was correlated with longer median overall survival (mOS) in all the patients (both P<0.001) or in subgroups with different regimens (all P<0.05), but not correlated with response rate (RR, all P>0.05). Multivariate analysis revealed that high JWA (HR 0.22; 95% CI 0.13-0.37; P<0.001) or XRCC1 (HR 0.36; 95% CI 0.21-0.63; P<0.001) mRNA expression emerged as the independent prognostic factors for ESCC patients in this cohort. But no significant difference in prognostic efficacy was found between JWA plus XRCC1 and JWA alone through ROC analysis. Further subgroup analysis showed cisplatin-based treatments could improve mOS of patients with low JWA expression (P<0.05), especially in those with low BRCA1 expression simultaneously (P<0.001); while in patients with high JWA expression, high BRCA1 mRNA expression was correlated with increased mOS in docetaxel-based treatments (P=0.044).

CONCLUSION

JWA, XRCC1and BRCA1 mRNA expression could be used as predictive markers in molecular staging for personalized therapy in patients with advanced ESCC who received first-line cisplatin- or docetaxel-based treatments.

Risk factors and gene expression in esophageal cancer

Esophageal cancer is a significant worldwide health problem because of its poor prognosis and high incidence in certain parts of the world. Tobacco smoke and alcohol consumption are significant risk factors for esophageal squamous cell carcinoma, whereas frequent gastroesophageal reflux and subsequent inflammatory reactions play a role in causing the adenocarcinoma. Esophageal carcinogenesis involves multiple genetic alterations. A large body of knowledge has been generated regarding molecular alterations associated with esophageal carcinogenesis. These alterations include aberrant cell cycle control, DNA repair, cellular enzymes, growth factor receptors, and nuclear receptors. This chapter reviews the most frequent gene alterations and their correlation with risk factors as well as the prevention strategies in esophageal cancer.

[Radiochemotherapy for oesophageal cancer: a locoregional failure history]

Esophageal cancer is characterized by various degrees of lymph node invasion and metastasis, both of which are associated with a poor prognosis. Exclusive concomitant radiochemotherapy (RCT) at a dose of 50 Gy delivered over 25 sessions, according to the RTOG 85-01 protocol, has led to improved five-year survival in 25% of patients, whereas no patients survive for five years using radiotherapy alone. Surgery, even when combined with preoperative RCT, also gives disappointing results for locally advanced tumors, which casts serious doubts on the usefulness of preoperative radiotherapy. By varying the fractionation schedule, the length of treatment or the radiotherapy volumes, it has become possible to obtain levels of locoregional relapse of around 35 to 45%. The increasing incidence of adenocarcinoma, which differs from epidermoid cancer with regard to the degree of lymph node invasion, has revived discussion on radiotherapy volumes. Given this difference between these two histological forms, we propose here a number of recommendations concerning radiotherapy volumes for patients presenting with cancer of the esophagus. Finally, analysis of the results for locoregional relapse according to the dose of radiation and the recommended radiotherapy volumes, has led us to investigate why increasing the dose of radiation has no impact in esophageal cancers.

[Resectable adenocarcinoma of the oesophagogastric junction care: which perioperative treatment?]

Adenocarcinoma of the oesophagogastric junction has an ominous prognosis. Until now, oesophageal adenocarcima care was close to the squamous cell cancer one whereas adenocarcinoma of the cardia was mixed with gastric cancers. Results from randomised studies mixed them without making distinctions. Nevertheless, context, natural history and clinical outcome differ. Five-year survival rate is around 40 %, all stages included. Results from several phase-III studies or meta-analysis allowed to define three therapeutic strategies applicable to adenocarcinoma of the oesophagus and the oesophagogastric junction. In Europe, in the case of a resectable tumour, preoperative chemotherapy became a standard treatment since results from the Magic trial. In the United States, post-operative radiochemotherapy according to the "Macdonald" scheme is used in case of a resected tumour with a R0 surgery. Actually, modern techniques of irradiation could reduce the rate of gastro-intestinal toxicities. The survival benefit from preoperative radiochemotherapy is still very controversial with high rates of postoperative morbidity and mortality. We have performed a review of the literature with a methodological analysis of data with a high level of evidence in order to advise perioperative treatment guidelines for patients with a resectable adenocarcinoma of the lower oesophagus or gastro-oesophageal junction. Results from pre- or postoperative strategies and the role of radiotherapy will need to be analysed in the future through a randomised study.

Gene expression profile changes correlating with radioresistance in human cell lines

PURPOSE

To identify gene expression profiles specific to radioresistance of human cells.

METHODS AND MATERIALS

Global gene expression profiles of a total of 15 tumor and normal fibroblast cell lines were analyzed using DNA microarrays and statistical clustering methods. Initially, six of the cell lines were categorized into radioresistant (RG) or nonradioresistant (NRG) groups according to the radiation dose required to reduce their survival to 10% (D10). Genes for which expression was specific to each group at 1 or 3 h after irradiation were identified using statistical procedures including analysis of variance and a two-dimensional hierarchical clustering method. The remaining nine cell lines were subjected to the k-nearest neighbor pattern classification.

RESULTS

The nine test cell lines were successfully classified by their D10 value using 46 and 44 genes for which transcription levels had significantly changed at 1 and 3 h after irradiation, respectively. Of these genes, 25 showed altered expression at both time points in the NRG or RG, but independently were unable to classify the test cell lines.

CONCLUSIONS

Radioresistant cell lines analyzed in this study showed certain radiation-induced changes in gene expression profiles that are different from the profile changes of the more-sensitive cell lines.