RESUMO
BACKGROUND: Resection remains the best treatment for carcinoma of the esophagus in terms of local control, but local recurrence and distant metastasis remain an issue after surgery. Chemo-radiotherapy (CRT) followed by surgery was associated with significantly improved survival benefit, but the effectiveness of neoadjuvant therapy in patients with resectable esophageal carcinoma remains controversial. The aim of this study was to evaluate the effects of neoadjuvant chemoradiotherapy in resectable esophageal carcinoma compared to surgery alone (SA). METHODS: A search for publications that compared the efficacy of CRT with SA in resectable esophageal carcinoma was conducted. After a rigorous review of the quality, the data were extracted from eligible trials. The major outcomes measures were odds ratios (ORs). The ORs with their corresponding 95% confidence intervals were the principal measure of effects. For the meta-analysis, Revman 5.3 software was used to analyze the combined pooled ORs using fixed- or random-effects models according to the heterogeneity. RESULTS: Our findings revealed that, compared with SA, neoadjuvant CRT was associated with improved overall survival (OS) and progression-free survival times, but the 3- and 5-year OS did not show a statistical difference (P≥0.05). The adjuvant chemotherapy group did not show significant improvement on reference rate and metastasis rate compared with the control group. CONCLUSION: CRT does significantly improve progression-free survival and OS in patients with esophageal cancer compared with SA. However, further assessment is still warranted on the role of CRT in future trials with well-selected patients.
RESUMO
Betulin is a common triterpene that can be readily obtained from various plants, particularly birch trees, in their natural environment. Specific tumor cells are sensitive to betulin, whereas healthy cells are not. Betulin was observed to stimulate programmed cell death of various cancer cell lines; however, the precise molecular mechanism of action of betulin remains unknown. The present study used colon cancer cells, in which mass apoptosis triggered by betulin was identified, and the apoptotic process was demonstrated to occur via the activation of caspase-3 and -9 pathways. In addition, release of cytochrome c was detected. Furthermore, the pro-apoptotic member of the Bcl-2 protein family, NOXA, was induced following treatment with betulin, and the downregulation of NOXA markedly suppressed the release of cytochrome c and apoptosis in colon cancer cells. Conversely, the overexpression of NOXA further enhanced betulin-induced apoptosis. The present study therefore offers novel insights into the mechanism of action of the natural compound betulin against tumors.
