PTK7 regulates radioresistance through nuclear factor-kappa B in esophageal squamous cell carcinoma.

Tumor radioresistance is a major reason for decreased efficiency of cancer radiation therapy. Although a number of factors involved in radioresistance have been identified, the molecular mechanisms underlying radioresistance of esophageal squamous cell carcinoma (ESCC) have not been elucidated. In this study, we investigated the role of oncogenic protein tyrosine kinase 7 (PTK7) in the resistance of ESCC to radiation therapy. ESCC cell lines with high PTK7 expression were more refractive to radiation than those with low PTK7 levels. In radioresistant ESCC cells, PTK7 knockdown by specific siRNAs decreased the survival of irradiated cells and increased radiation-induced apoptosis, while in radiosensitive ESCC cells, PTK7 overexpression promoted cell survival and inhibited radiation-induced apoptosis. We hypothesized that PTK7 could regulate the activation of transcription factor NF-kB known for its role in cancer radioresistance. Our results indicated that the inhibition of PTK7 suppressed nuclear translocation of NF-kB subunit p65 induced by radiation, suggesting relevance of PTK7 expression with NF-kB activation in radioresistant ESCC. Furthermore, the levels of inhibitor of apoptosis proteins (IAPs), XIAP, and survivin, encoded by NF-kB-regulated genes, were induced in irradiated radioresistant cells but not in radiosensitive cells, while PTK7 knockdown downregulated IAP expression. Our findings revealed a novel mechanism underlying radioresistance in ESCC, which is associated with PTK7 and NF-kB-dependent apoptosis. These results suggest that the manipulation of PTK7 expression can be instrumental in enhancing ESCC response to radiotherapy. This study demonstrates that PTK7 plays a significant role in ESCC radioresistance via the NF-kB pathway.

Epigenetic regulation of the novel tumor suppressor cysteine dioxygenase 1 in esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC), the most common subtype of esophageal cancer in East Asian countries, is still associated with a poor prognosis because of the high frequency of lymph node metastasis and invasion. In our previous study, we identified a novel methylation gene, cysteine dioxygenase 1 (CDO1) that is involved in the conversion of cysteine to cysteine sulfinate, and plays a key role in taurine biosynthesis. Decreased expression of CDO1 was observed in ESCC cell lines and tumors derived from patient tissues, and CDO1 silencing could be reversed by treatment with 5-aza-2'-deoxycytidine in six ESCC cell lines. Forced expression of CDO1 in three different ESCC cell lines, TE-4, TE-6, and TE-14, significantly decreased tumor cell growth, cell migration, invasion, and the ability of colony formation. Although CDO1 expression was not found to significantly correlate with survival in ESCC patients, our results suggest that methylation-regulated CDO1 may represent a functional tumor suppressor and a potentially valuable diagnostic biomarker for ESCC.

Oncogenic role of protein tyrosine kinase 7 in esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is a common subtype of esophageal cancer that is particularly prevalent in East Asian countries. Our previous expression profile analysis showed that the gene encoding protein tyrosine kinase 7 (PTK7) is upregulated in ESCC tissues. Here, we aimed to validate PTK7 as a prognostic factor and a candidate target for molecular treatment of ESCC. Both RT-PCR and Western blot analysis of tissues from ESCC patients revealed that PTK7 was significantly upregulated in tumor tissue samples of ESCC. Immunohistochemical staining of PTK7 showed that increased expression of PTK7 was inversely correlated with overall survival (P = 0.021). In vitro knockdown of PTK7 inhibited proliferation, survival, wound healing, and invasion of ESCC cells. In addition, PTK7 knockdown decreased phosphorylation of Akt, Erk, and focal adhesion kinase (FAK), important determinants of cell proliferation, survival, and migration. Therefore, our findings suggest that PTK7 has potential as a prognostic marker for ESCC and might also be a candidate for targeted therapy in the treatment of ESCC.

Accuracy of 16-channel multi-detector row chest computed tomography with thin sections in the detection of metastatic pulmonary nodules.

OBJECTIVES: The inaccuracy of conventional CT makes open thoracotomy and manual palpation inevitable in pulmonary metastasectomy. However, the introduction of multi-detector row CT technology made it possible to detect pulmonary nodules with a diameter of 1mm. The purpose of this study was to investigate the accuracy of 1mm thin-section 16-channel multi-detector row CT (TSMDCT) in the detection of metastatic pulmonary nodules. METHODS: Twenty-seven patients who underwent pulmonary metastasectomy between November 2005 and September 2006 were included in the study. The primary tumors were colorectal cancer (n=11), renal cell carcinoma (n=5), osteosarcoma (n=3), hepatocellular carcinoma (n=3), thymic tumor (n=2), bladder cancer (n=1), thyroid cancer (n=1), and primitive neuroectodermal tumor (n=1). TSMDCT was performed in all patients in order to evaluate the location and number of metastatic nodules. The patients were divided into osteosarcoma and non-osteosarcoma groups, and the accuracy of TSMDCT was evaluated by comparison with the pathologic diagnosis of metastatic nodules. RESULTS: A total of 117 nodules were detected preoperatively by TSMDCT scanning, and 198 nodules were resected during the operation. A total of 101 nodules were pathologically confirmed to be metastatic nodules. In the osteosarcoma group, the sensitivity, specificity, positive predictive value, and negative predictive value were 34%, 93%, 92%, and 38%, respectively. In the non-osteosarcoma group, the sensitivity, specificity, positive predictive value, and negative predictive value were 97%, 54%, 64%, and 96%, respectively. Subgroup analysis in the non-osteosarcoma group revealed that nodule size over 5mm, number of metastatic nodules less than five, and disease-free interval over 24 months showed 100% sensitivity by preoperative TSMDCT. CONCLUSIONS: TSMDCT with 1mm thickness image reconstruction showed high detection rate of metastatic pulmonary nodules in the patients with non-osteosarcoma. In highly selected subgroups, TSMDCT detected all the metastatic nodules which manual palpation could detect. Further study on the application of TSMDCT in thoracoscopic metastasectomy should be performed.

MiR-338-5p enhances the radiosensitivity of esophageal squamous cell carcinoma by inducing apoptosis through targeting survivin.

Radioresistance is a challenge in the treatment of esophageal squamous cell carcinoma (ESCC). MicroRNAs (miRNAs) are known to play an important role in the functional modification of cancer cells and recent studies have reported miRNA-mediated radiotherapy resistance. However, further research is necessary to reveal the regulation mechanisms, and treatment strategies using miRNA are yet to be established for ESCC. We compared the miRNA expression profiles of ESCC parental (TE-4) and acquired radioresistance (TE-4R) cell lines using a miRNA microarray and qRT-PCR. Our data showed that miR-338-5p, one of the target miRNA biomarkers, was significantly downregulated in TE-4R. Ectopic overexpression of miR-338-5p induced apoptosis and sensitivity to radiation treatment by interfering with survivin, which is a known inhibitor of apoptosis. Overexpression of survivin reversed miR-338-5p-induced apoptosis. Tumor xenograft experiments indicated that therapeutic delivery of the miR-338-5p mimics via direct injection into tumor mass increased sensitivity to radiation therapy. In conclusion, our findings suggest that miR-338-5p is a potential radiosensitizer and may be a therapeutic biomarker for radioresistant in ESCC.

Pulmonary Metastasectomy in Adult Patients with Synovial Sarcoma: A Single-Center Experience.

BACKGROUND: This study assessed the efficacy of pulmonary metastasectomy for synovial sarcoma in adult patients. METHODS: Fifty patients, diagnosed with pulmonary metastasis from June 1990 to August 2010, were reviewed retrospectively. Twenty-eight patients underwent complete pulmonary metastasectomy, and their survival was evaluated. Age, sex, time to metastatic progression, laterality, number of tumors, size of largest nodule, and number of metastasectomies were analyzed as potential prognostic factors. RESULTS: In all, 29 patients underwent at least one pulmonary metastasectomy, and 51 resections were performed. One intraoperative mortality occurred, and the 5-year survival rate was 58.4%. Bilateral metastases and early metastatic progression were associated with poor survival in multivariate analyses. CONCLUSION: Surgical resection can be a good option for treating pulmonary metastasis in patients with synovial sarcoma. Repeated resection was feasible with low mortality and morbidity.

Protein tyrosine kinase 7 plays a tumor suppressor role by inhibiting ERK and AKT phosphorylation in lung cancer.

Protein tyrosine kinase 7 (PTK7) is a catalytically inactive receptor tyrosine kinase that is also known as colon carcinoma kinase-4 (CCK-4). Recent reports have shown that PTK7 plays an important role in carcinogenesis, and it is known to be upregulated in gastric, colon and esophageal cancer, as well as in liposarcoma. However, the role of PTK7 in lung cancer has not been investigated. The aim of the present study was to investigate the expression levels and the role of PTK7 in lung cancer. We found that PTK7 expression was downregulated at the mRNA as well as protein levels in human lung squamous cell carcinoma (LSCC). Upon investigation of the functional role of PTK7 in LSCC, we found that overexpression of PTK7 in LSCC cells resulted in inhibition of cell proliferation, invasion and migration. Furthermore, we confirmed that these phenotypic changes are associated with the inactivation of AKT and ERK. Our findings suggest that PTK7 has different oncogenic roles in organs and target tumors.

Cetuximab inhibits cisplatin-induced activation of EGFR signaling in esophageal squamous cell carcinoma.

A malignant esophageal cancer, squamous cell carcinoma is one of the most prevalent cancers. Despite the use of present surgical techniques combined with various treatment modalities, the overall 5-year survival rate remains at 15-34%. Epidermal growth factor receptor (EGFR) is the most well studied receptor in various cancers and EGFR overexpression is detected in 40% of esophageal squamous cell carcinomas (ESCCs) and ESCC cell lines. To examine the EGFR antibody combination effect, we used treatment with cisplatin and cetuximab in ESCC cell lines, TE-4 and TE-8. Combination of cetuximab and cisplatin resulted in a growth inhibition only in the EGFR overexpressed TE-8 cell line. Furthermore, we confirmed that cisplatin-induced EGFR activation was inhibited by cetuximab in TE-8 but not in TE-4 cells. Our data suggest that cetuximab combined with cisplatin exerts antitumorigenic effects in vitro and in vivo via suppression of EGF signaling, which can be applied toward targeted ESCC treatments.

Integrin alpha 6: a novel therapeutic target in esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC), the most common subtype of esophageal cancer in East Asian countries, is a devastating disease characterized by distinctly high incidence and mortality rates. Our previous expression profile analysis showed that integrin alpha 6 (ITGA6) is highly expressed in ESCC tissues. To validate cell surface expression of ITGA6 as a novel target in ESCC, we investigated ITGA6 expression in tumor tissue samples and cell lines of ESCC and found that ITGA6 was upregulated in these cells. In vitro knockdown of ITGA6 in ESCC cells resulted in inhibition of cell proliferation, invasion and colony formation. In addition, we demonstrated that ITGA6 associates with integrin beta 4 (ITGB4), and that this heterodimer complex is upregulated in both ESCC tissues and cell lines. Moreover, our biodistribution results in an ESCC xenograft model indicated that ITGA6 is a possible target for antibody-related diagnostic and therapeutic modalities in ESCC. Thus, our findings suggest that ITGA6 plays an important role in tumorigenesis in ESCC and represents a potential therapeutic target in the treatment of ESCC.

BRCA1 gene mutation in thymic malignant melanoma.

We present a patient with triple primary malignancies: thyroid cancer, ovarian cancer, and thymic malignant melanoma. We suspected that gene mutations were involved in the occurrence of these multiple primary cancers, and blood analysis revealed the presence of BRCA1 gene mutations.

Genome-wide analysis of DNA methylation and the gene expression change in lung cancer.

INTRODUCTION: The recent DNA methylation studies on cancers have revealed the necessity of profiling an entire human genome and not to restrict the profiling to specific regions of the human genome. It has been suggested that genome-wide DNA methylation analysis enables us to identify the genes that are regulated by DNA methylation in carcinogenesis. METHODS: So, we performed whole-genome DNA methylation analysis for human lung squamous cell carcinoma (SCC), which is strongly related with smoking. We also performed microarrays using 21 pairs of normal lung tissues and tumors from patients with SCC. By combining these data, 30 hypermethylated and down-regulated genes, and 22 hypomethylated and up-regulated genes were selected. The gene expression level and DNA methylation pattern were confirmed by semiquantitative reverse-transcriptase polymerase chain reaction and pyrosequencing, respectively. RESULTS: By these validations, we selected five hypermethylated and down-regulated genes and one hypomethylated and up-regulated gene. Moreover, these six genes were proven to be actually regulated by DNA methylation by confirming the recovery of their DNA methylation pattern and gene expression level using a demethylating agent. The DNA methylation pattern of the CYTL1 promoter region was significantly different between early and advanced stages of SCC. CONCLUSION: In conclusion, by combining the whole-genome DNA methylation pattern and the gene expression profile, we identified the six genes (CCDC37, CYTL1, CDO1, SLIT2, LMO3, and SERPINB5) that are regulated by DNA methylation, and we suggest their value as target molecules for further study of SCC.

Good long-term outcomes after surgical treatment of simple and complex pulmonary aspergilloma.

BACKGROUND: The long-term outcomes of pulmonary aspergilloma have been known to depend on the underlying lung disease. We analyzed the surgical long-term outcomes for both simple and complex aspergilloma. METHODS: From 1981 to 1999, 90 surgical procedures were performed on 88 patients with pulmonary aspergilloma. The patients included 44 men and 44 women with a median age of 41 years (range, 12 to 69 years). The underlying lung diseases in the 72 complex aspergilloma cases were 57 tuberculosis (65%), 14 bronchiectases (16%), and 1 emphysema (1.1%). Sixteen (18%) had no underlying lung disease. The procedures performed were 52 lobectomies, 33 segmentectomies or wedge resections, 3 pneumonectomies, and 2 cavernostomies. RESULTS: One case of operative mortality (1.1%) occurred in complex aspergilloma. Among the other patients, 24 complications developed (27%): 11 prolonged air leaks (longer than 7 days), 7 persistent spaces, 3 postoperative bleedings, 2 empyemas, 2 pneumonias, and 1 wound infection. Risk factor analysis revealed old age and complex aspergilloma as significant risk factors for postoperative complication. One simple and 13 complex aspergilloma patients died during the follow-up period. Only 4 deaths were caused by pulmonary problems. The 10-year actuarial survival rates of simple and complex aspergilloma were 80.0% and 79.6%, respectively. There was no difference between the long-term survival of simple and complex aspergilloma. CONCLUSIONS: Although the postoperative morbidity rate was higher in complex aspergilloma, surgical treatment for both simple and complex aspergilloma could achieve satisfactory long-term outcomes in selected groups of patients.