RNA interference for epidermal growth factor receptor enhances the radiosensitivity of esophageal squamous cell carcinoma cell line Eca109

The present study investigated the effects of small interfering RNAs (siRNAs) specific to the epidermal growth factor receptor (EGFR) gene, on the radiosensitivity of esophageal squamous cell carcinoma cells. EGFR gene siRNAs (EGFR-siRNA) were introduced into esophageal cancer Eca109 cells using Lipofectamine® 2000. The EGFR messenger (m)RNA expression levels, EGFR protein expression and cell growth were assessed using reverse transcription-polymerase chain reaction analysis, western blot analysis and a Cell Counting Kit-8 (CCK-8), respectively. In addition, colony assays were used to determine the inhibitory effects of X-ray radiation on EGFR-silenced cells. EGFR mRNA and protein levels were reduced in the Eca109 cells transfected with EGFR-siRNA. The relative EGFR mRNA expression levels were reduced to 26.74, 9.52 and 4.61% in Eca109 cells transfected with EGFR-siRNA1, 2 and 3, respectively. These mRNA levels were significantly reduced compared with the those of the control group (42.44%; P<0.0001). Transfection with siRNA3 resulted in the greatest reduction in EGFR mRNA expression, with an inhibition rate of 85%. The relative EGFR protein expression levels were reduced to 24.05, 34.91 and 34.14% in Eca109 cells transfected with EGFR-siRNA1, 2 and 3, respectively. These protein levels were significantly reduced compared with those of the control group (78.57%; P<0.0001). Transfection with siRNA1 resulted in the greatest reduction in EGFR protein expression, with an inhibition rate of 72.84%. This reduction in EGFR expression inhibited the proliferation of Eca109 cells, which was identified using the CCK-8 assay. The proliferation inhibition ratio was 28.2%. The cells treated with irradiation in addition to EGFR-siRNA, demonstrated reduced radiobiological parameters (D0, Dq and SF2) compared with those of cells treated with irradiation only, with a sensitization enhancing ratio of 1.5. In conclusion, suppression of EGFR expression may enhance the radiosensitivity of esophageal cancer Eca109 cells and therefore may represent a promising approach for future clinical practice.

Definitive chemoradiotherapy for esophageal carcinoma

Radiation therapy plays an important role in the treatment of esophageal cancer. Radiation therapy may be combined with chemotherapy, used as a component of induction therapy, used in the adjuvant setting, or used for palliation of advanced disease. Chemotherapy is also occasionally used as a solitary treatment modality for patients with esophageal cancer. Current treatment protocols include multiple agents, and agents directed against specific molecular targets have been investigated in clinical trials. This article discusses future directions related to the selection of radiation treatment protocols, novel targeted chemotherapeutic agents, and the selection of patients for surgery.

SCOPE1: a randomised phase II/III multicentre clinical trial of definitive chemoradiation, with or without cetuximab, in carcinoma of the oesophagus

BACKGROUND

Chemoradiotherapy is the standard of care for patients with oesophageal cancer unsuitable for surgery due to the presence of co-morbidity or extent of disease, and is a standard treatment option for patients with squamous cell carcinoma of the oesophagus. Modern regimens of chemoradiotherapy can lead to significant long-term survival. However the majority of patients will die of their disease, most commonly with local progression/recurrence of their tumours. Cetuximab may overcome one of the principal mechanisms of tumour radio-resistance, namely tumour repopulation, in patients treated with chemoradiotherapy.The purpose of this research is first to determine whether the addition of cetuximab to definitive chemoradiotherapy for treatment of patients with non-metastatic carcinoma of the oesophagus is active (in terms of failure-free rate), safe, and feasible within the context of a multi-centre randomised controlled trial in the UK. If the first stage is successful then the trial will continue to accrue sufficient patients to establish whether the addition of cetuximab to the standard treatment improves overall survival.

METHODS/DESIGN

SCOPE1 is a two arm, open, randomised multicentre Phase II/III trial. Eligible patients will have histologically confirmed carcinoma of the oesophagus and have been chosen to receive definitive chemoradiotherapy by an accredited multidisciplinary team including a specialist Upper GI surgeon. 420 patients will be randomised to receive definitive chemoradiotherapy with or without cetuximab using a 1:1 allocation ratio.During Phase II of the study, the trial will assess safety (toxicity), activity (failure-free rate) and feasibility (recruitment rate and protocol dose modifications/delays) in 90 patients in the experimental arm. If the experimental arm is found to be active, safe, and feasible by the Independent Data Monitoring Committee then recruitment will continue into Phase III. This second stage will recruit a further 120 patients into each arm and compare the overall survival of both groups.All patients randomised into Phase II will contribute to the Phase III comparison of overall survival. In addition to overall survival, Phase III of the study will also assess toxicity, health related quality of life and cost effectiveness. A detailed radiotherapy protocol and quality assurance procedure has been incorporated into this trial.

TRIAL REGISTRATION

ISRCTN: ISRCTN47718479.

Barrett's esophagus: treatments of adenocarcinomas II

The following topics are explored in this collection of commentaries on treatments of adenocarcinomas related to Barrett's esophagus: the importance of intraoperative frozen sections of the margins for the detection of high dysplasia; the preferable way for sentinel node dissection; the current role of robotic surgery and of video-endoscopic approach; the value of the Siewert's classification of adenocarcinomas; the indications of two-step esophagectomy; the evaluation of pathological complete response; the role of PET scan in staging and response assessment; the role of p53 in the selection of adenocarcinomas patients; chemotherapy regimens for adenocarcinomas; the use of monoclonal antibodies in the control of cell proliferation; he attempt to define a stage-specific strategy, and the possible indications of selective therapy; and changes in mortality rates from esophageal cancer.

Esophageal cancer: adjuvant therapy

In the United States, esophageal cancer is an uncommon but aggressive malignancy. Prior research has focused on the incorporation of chemotherapy and radiotherapy in both the pre- and postoperative setting. Both squamous cell and adenocarcinoma histologies have been treated in trials, with adenocarcinoma now the predominant histology seen in the United States. Although preoperative chemotherapy improves survival compared with surgery alone, the addition of concurrent radiotherapy to preoperative chemotherapy improves rates of curative resection, reduces local tumor recurrence, and achieves a significant rate of pathologic complete response. Combined preoperative chemoradiotherapy is the preferred preoperative strategy for locally advanced esophageal cancers in the United States. Definitive chemoradiotherapy alone appears to be equivalent in terms of overall survival compared with chemoradiotherapy followed by surgery in squamous cancers, although the addition of surgery after chemoradiotherapy may afford superior local control of disease. Postoperatively, survival is improved with postoperative chemotherapy and radiotherapy in adenocarcinoma of the gastroesophageal junction, if none has been delivered preoperatively. Ongoing research involves evaluating regimens with newer chemotherapeutic drugs, such as paclitaxel or irinotecan, as well as the incorporation of targeted molecular therapies.

Activation of growth factor receptors in esophageal cancer--implications for therapy

Esophageal cancer is a highly aggressive disease and is the seventh most common cause of cancer-related death in the western world. Worldwide, it ranks as the sixth most frequent cause of cancer death. Despite advances in surgical techniques and treatment, the prognosis of esophageal cancer remains poor, with very few long-term survivors. The need for novel strategies to detect esophageal cancer earlier and to improve current therapy is urgent. It is well established that growth factors and growth factor receptor-mediated signaling pathways are important components of the transformation process in many forms of cancer, including esophageal cancer. With the recent advances in drug development, there are emerging possibilities to use growth factor signal transduction pathways in targeted therapy. This review provides a summary of the role of growth factors and their receptors in esophageal cancer and discusses their potential roles as biomarkers and as targets in therapy.

Paclitaxel given by a weekly 1-h infusion in advanced esophageal cancer

BACKGROUND

The purpose of the study was to evaluate the efficacy of weekly paclitaxel (Taxol) in advanced esophageal cancer.

PATIENTS AND METHODS

One hundred and two patients with advanced esophageal cancer were treated with paclitaxel 80 mg/m2 weekly over a 1-h infusion. One cycle was defined as 4 weeks of therapy. Ninety-five patients were assessable for toxicity and 86 patients who completed at least two cycles of treatment were assessable for response. Sixty-six patients had adenocarcinoma (66%) and 65 patients (68%) had no prior chemotherapy.

RESULTS

A median of three cycles was delivered (range 1-11). Partial responses (PRs) were seen in 11 patients [13%, 95% confidence interval (CI) 6% to 20%]. In patients without prior chemotherapy, PRs were seen in 10 patients (15%, 95% CI 6% to 24%), with comparable response in adenocarcinoma (8/50, 16%) and squamous carcinoma (2/15, 13%). Limited response was seen in patients with prior chemotherapy (1/21, 5%). The median duration of response was 172 days. The median survival was 274 days. Therapy was well tolerated with minimal hematologic or grade 3 or 4 toxicity.

CONCLUSION

Weekly paclitaxel has limited activity in esophageal cancer. The median survival, modest activity, and tolerance of therapy indicate that weekly paclitaxel may be an option in patients unable to tolerate combination chemotherapy.

Multimodality treatment of esophageal cancer: A review of the current status and future directions

Surgical resection will cure only 15% to 20% of patients with seemingly localized esophageal cancer. Multimodality therapy has the potential to increase the cure rate by improving locoregional control and preventing systemic relapse. Randomized trials demonstrate that chemoradiation followed by surgery decreases local relapse as compared with surgery alone; however, the effect on overall survival remains uncertain. The additional impact of surgery following chemoradiation also remains unclear, with two randomized trials demonstrating an improvement in locoregional control without a benefit in survival. Morbidity and mortality of trimodality therapy have limited potential gains. Incorporation of docetaxel, irinotecan, and oxaliplatin into chemotherapy regimens prior to chemoradiation or as adjuvant therapy may decrease systemic recurrence. New radiation sensitizers may improve locoregional control. Biologic agents, such as cetuximab, trastuzumab, erlotinib, and bevacizumab, may enhance chemoradiation and target systemic micrometastases. Advances in radiation oncology and surgery may decrease morbidity and mortality from trimodality therapy, improving patient outcome.