The incidence of malignant melanoma is growing rapidly worldwide and there is still no effective therapy for metastatic disease. Melanoma is the second most common cancer among young adults in the UK, where incidence rates have more than quadrupled since the 1970s. Increased expression of a number of DNA repair genes has been reported in melanoma and this likely contributes to its extreme resistance to conventional DNA-damaging chemotherapeutics. One such chemotherapeutic that is effective against a range of other cancers, but not melanoma, is cisplatin. The DNA repair proteins ERCC1 and XPF are needed to remove cisplatin-induced DNA damage and we have investigated the response of these proteins to cisplatin in melanoma. The expression of both genes is induced by cisplatin. Use of a MEK inhibitor showed that ERCC1, but not XPF induction was regulated by the mitogen-activated protein kinase (MAPK) pathway, with reduction in expression of DUSP6, the phosphatase that inactivates the extracellular signal-regulated kinase (ERK), being particularly important. DUSP6 overexpression prevented cisplatin induction of both ERCC1 and XPF, resulting in increased sensitivity to cisplatin. A novel ERCC1 mRNA was found that initiated upstream of the normal transcription initiation site, and was strongly regulated by both cisplatin and the MAPK pathway and its role in cisplatin resistance merits further study. The cisplatin induction of ERCC1 and XPF provides important insights into the resistance of melanoma to DNA-damaging chemotherapeutics, which is one of the major obstacles to melanoma treatment.
Approximately 15-20% of ovarian cancer patients receiving platinum-based chemotherapy are primary platinum-resistant. Identification of these patients and transfer to other more effective therapy could reduce the morbidity of ovarian cancer. ERCC1 is a DNA repair gene which can complex with XPF to repair cisplatin-induced DNA damage and cause chemotherapy resistance. In this study, we found a novel ERCC1 transcript initiated upstream of the normal transcription initiation site. The expression of this larger ERCC1 transcript dramatically increased following cisplatin treatment in ovarian cancer cells and was regulated by the MAPK pathway. This phenomenon conferred enhanced cisplatin resistance on ovarian cancer cells, and was confirmed with chemosensitive and chemoresistant patients’ samples. Our data suggested that larger ERCC1 transcript levels correlated with the outcome of platinum-based chemotherapy.
Background:Cerebral glucose metabolism changes are always observed in patients suffering from malignant tumors. This preliminary study aimed to investigate the brain glucose metabolism changes in patients with lung cancer of different histological types.Methods:One hundred and twenty patients with primary untreated lung cancer, who visited People's Hospital of Zhengzhou University from February 2012 to July 2013, were divided into three groups based on histological types confirmed by biopsy or surgical pathology, which included adenocarcinoma (52 cases), squamous cell carcinoma (43 cases), and small-cell carcinoma (25 cases). The whole body 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) of these cases was retrospectively studied. The brain PET data of three groups were analyzed individually using statistical parametric maps (SPM) software, with 50 age-matched and gender-matched healthy controls for comparison.Results:The brain resting glucose metabolism in all three lung cancer groups showed regional cerebral metabolic reduction. The hypo-metabolic cerebral regions were mainly distributed at the left superior and middle frontal, bilateral superior and middle temporal and inferior and middle temporal gyrus. Besides, the hypo-metabolic regions were also found in the right inferior parietal lobule and hippocampus in the small-cell carcinoma group. The area of the total hypo-metabolic cerebral regions in the small-cell carcinoma group (total voxel value 3255) was larger than those in the adenocarcinoma group (total voxel value 1217) and squamous cell carcinoma group (total voxel value 1292).Conclusions:The brain resting glucose metabolism in patients with lung cancer shows regional cerebral metabolic reduction and the brain hypo-metabolic changes are related to the histological types of lung cancer.
Abstract. The bark of Pinus massoniana is a traditionalChinese medicine for the treatment of various health disorders. Previous studies have demonstrated that P. massoniana bark extract (PMBE) may induce the apoptosis of hepatoma and cervical cancer cells. However, whether PMBE is able to inhibit the migration of lung cancer cells requires further investigation. In the current study, the effects of PMBE on the viability of human lung cancer A549 cells were detected using an MTT assay. The migration of lung cancer cells following exposure to PMBE were quantified using wound healing and Transwell assays, respectively. The expression levels of matrix metalloproteinase (MMP)-9 were determined using western blotting. The results revealed that PMBE significantly inhibited the growth of the lung cancer cells. In addition, the wound closure rate and the migration of the lung cancer cells were suppressed by PMBE. Furthermore, the expression levels of MMP-9 were reduced. These findings indicated that PMBE is able to restrict the migration and invasion of lung cancer cells, and that PMBE may serve as a novel therapeutic agent for patients with metastatic lung cancer in the future.
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