Disruption of cytochrome c oxidase function induces the Warburg effect and metabolic reprogramming.

Defects in mitochondrial oxidative phosphorylation complexes, altered bioenergetics and metabolic shift are often seen in cancers. Here we show a role for the dysfunction of the electron transport chain component cytochrome c oxidase (CcO) in cancer progression. We show that genetic silencing of the CcO complex by shRNA expression and loss of CcO activity in multiple cell types from the mouse and human sources resulted in metabolic shift to glycolysis, loss of anchorage-dependent growth and acquired invasive phenotypes. Disruption of the CcO complex caused loss of transmembrane potential and induction of Ca2+/Calcineurin-mediated retrograde signaling. Propagation of this signaling includes activation of PI3-kinase, IGF1R and Akt, Ca2(+)-sensitive transcription factors and also TGFß1, MMP16 and periostin, which are involved in oncogenic progression. Whole-genome expression analysis showed the upregulation of genes involved in cell signaling, extracellular matrix interactions, cell morphogenesis, cell motility and migration. The transcription profiles reveal extensive similarity to retrograde signaling initiated by partial mitochondrial DNA depletion, although distinct differences are observed in signaling induced by CcO dysfunction. The possible CcO dysfunction as a biomarker for cancer progression was supported by data showing that esophageal tumors from human patients show reduced CcO subunits IVi1 and Vb in regions that were previously shown to be the hypoxic core of the tumors. Our results show that mitochondrial electron transport chain defect initiates a retrograde signaling. These results suggest that a defect in the CcO complex can potentially induce tumor progression.

Expression of BMP-7 in human gastric cancer and its clinical significance.

BACKGROUND: Bone morphogenetic protein-7 (BMP-7) is a signalling molecule belonging to the transforming growth factor--superfamily. Recent studies have demonstrated the clinical impact of BMP-7 expression in various human cancers. However, there have been few reports detailing this in gastric cancer. METHODS: We immunohistochemically investigated the expression of BMP-7 in 233 gastric cancer patients to disclose the clinicopathological features of BMP-7-positive gastric cancer. RESULTS: Immunohistochemically, in human gastric cancer, BMP-7 expression was identified in cellular membranes but also in the cytoplasm of cancer cells. Bone morphogenetic protein-7-positive expression was found in 129 of 233 patients (55%). Bone morphogenetic protein-7 expression was correlated with tumour size, nodal involvement, lymphatic invasion, venous invasion and histology (P<0.05). Bone morphogenetic protein-7 expression was significantly correlated with patient postoperative outcome, especially in the undifferentiated group. Multivariate analysis revealed BMP-7 expression as one of the independent prognostic factors next to the depth of invasion and nodal involvement (P<0.01). CONCLUSIONS: From the data collected, it would be appropriate to conclude on the possible regulation of gastric cancer progression by autocrine or paracrine BMP-7 loops. We can use BMP-7 expression as one of the strong predictors of risk of tumour recurrence in gastric cancer.

Cyclooxygenase-2 expression is related to prognosis in patients with esophageal squamous cell carcinoma.

AIM: Esophageal carcinoma is one of the most aggressive malignancies. Many studies have examined various biological factors associated with the malignant potential of esophageal carcinoma. Cyclooxygenase (COX)-2 is overexpressed in various types of human malignancies, including esophageal carcinomas. Although some groups have described COX-2 expression in esophageal adenocarcinoma, few studies have reported COX-2 expression in esophageal squamous cell carcinoma (ESCC). METHODS: We immunohistochemically investigated relationships between COX-2 overexpression in surgical specimens of primary tumors in 228 patients with ESCC. Relationships between COX-2 expression and clinicopathological factors, including prognosis, were analyzed. COX-2 expressions were classified into 4 criteria: Score 0, no staining; Score 1, <10% staining; Score 2, 10-90% staining; and Score 3, >90% staining. RESULTS: Scores of COX-2 immunoreactivity in 228 patients were as follows: Score 0, 21 of 228; Score 1, 71of 228; Score 2, 117 of 228; and Score 3, 19 of 228, respectively. COX-2 expression was significantly correlated with depth of invasion and tumor stage (p=0.03 and p=0.04, respectively). The 5-year survival rate of patients decreased significantly with increased expression of COX-2 (p=0.005). Multivariate regression analysis indicated COX-2 expression as an independent prognostic factor for ESCC. CONCLUSIONS: COX-2 overexpression was significantly correlated with depth of invasion, tumor stage and survival in ESCC. Evaluation of COX-2 expression should be useful for determining tumor properties, including prognosis, in patients with ESCC.

Isolated tumour cells in blood and E-cadherin expression in oesophageal squamous cell cancer.

BACKGROUND: Patients with oesophageal squamous cell carcinoma have a high rate of recurrence, even after curative resection. The aim of this study was to examine the correlation between the presence of isolated tumour cells (ITCs) in the blood and recurrence, and between the presence of ITCs and E-cadherin expression in the primary tumour in these patients. METHODS: Blood samples obtained immediately before and after resection in 125 patients with oesophageal squamous cell carcinoma were examined by real-time reverse transcription-polymerase chain reaction using carcinoembryonic antigen mRNA. Blood samples from 28 healthy volunteers and 42 patients with benign diseases were used as controls. RESULTS: Seventy-seven patients (61.6 per cent) were ITC positive. ITC positivity correlated significantly with tumour depth, lymph node metastasis, stage, lymphatic invasion and venous invasion. Multivariable analysis revealed that tumour depth and ITC positivity were independent factors for a shortened haematogenous disease-free interval. A significant correlation was found between ITC positivity and reduced E-cadherin expression in the primary tumour (P < 0.001). ITC-positive patients with preserved E-cadherin expression had a longer disease-free interval (P = 0.016), haematogenous disease-free interval (P = 0.020) and overall survival (P = 0.004) than those with reduced E-cadherin expression. CONCLUSION: Examination of ITCs in the blood is useful for predicting haematogenous recurrence in patients with oesophageal squamous cell carcinoma.

Randomized controlled study on preoperative chemoradiotherapy followed by surgery versus surgery alone for esophageal squamous cell cancer in a single institution.

The purpose of the present study was to compare the clinical results between preoperative chemoradiotherapy followed by surgery (CRT group) and surgery alone (Surgery group) by a randomized controlled study. Twenty-two patients were assigned to the CRT group and 23 to the Surgery group. A total radiation dose of 40 Gy was applied and in the same period, intravenous chemotherapy was performed using cisplatin (7 mg over 2 h) and 5-fluorouracil (5-FU; 350 mg over 24 h). Surgical treatment was performed in 20 patients in the CRT group except for two patients with bone metastasis after CRT. According to histological effects of primary tumors, the number of patient with Grades 1, 2 and 3 was 11, 7 and 3, respectively. Frequency of lymphatic and venous invasion was significantly lower in the CRT group than in the Surgery group. The 5-year survival rate was 57% in the CRT group and 41% in the Surgery group (P = 0.58). According to the histological effect in the CRT group, 5-year survival was 30% for Grade 1, 83% for Grade 2 and 100% for Grade 3 (P = 0.0069). This randomized trial did not demonstrate a statistically significant survival difference between the CRT group and the Surgery group.

Expression of osteopontin in oesophageal squamous cell carcinoma.

Osteopontin is a multifunctional 34 kDa extracellular matrix protein with a cell-binding domain. It is involved cell adhesion and cell migration and is therefore considered to influence tumorigenesis and/or metastasis. The purpose of the present study was to evaluate the clinical significance of Osteopontin expression in oesophageal squamous cell carcinoma (ESCC). In the present study, we immunohistochemically investigated the relationship between Osteopontin expression and clinicopathological factors including prognosis in surgical specimens of primary tumours in 175 patients with ESCC. Osteopontin was expressed in 48% of 175 patients. Osteopontin expression was significantly correlated with lymph node metastasis, lymphatic invasion, and stage (P=0.0015, 0.037 and 0.033, respectively). Tumours with expressing Osteopontin exhibited more lymph node metastasis, lymphatic invasion and advanced stage than the tumour with negative Osteopontin expression. Five-year survival rate was better in patients with negative Osteopontin expression than in those with positive Osteopontin expression (P=0.035). However, multivariate analysis revealed that Osteopontin expression was not an independent prognostic factor. As our findings suggest that Osteopontin may play an important role in progress of ESCC, the evaluation of Osteopontin expression is useful for predicting the malignant properties of ESCC.

The role of salvage surgery for recurrence of esophageal squamous cell cancer.

AIM: A consensus treatment strategy for recurrent esophageal squamous cell cancer (ESCC) has not been established. The purpose of the present study was to analyse the mode of recurrence, and evaluate the role of surgical salvage treatment in recurrence of ESCC. METHODS: Recurrence was detected in 131 of 367 consecutive patients with ESCC. We retrospectively analysed the mode of recurrence and treatment for recurrence. Recurrence was divided into four types; lymph node, hematogeneous, mixed and local. Treatments were classified into four groups; chemotherapy alone (C group), radiation therapy +/- chemotherapy (R group), surgery +/- other therapy (S group), and no therapy (N group). RESULTS: Of the 131 recurrences, the number of patients with lymph node, hematogeneous, mixed and local recurrence was 43, 44, 40 and 4, respectively. The number of patients in the C, R, S, N groups was 35, 35, 24 and 37, respectively. Of the 24 patients who received surgical treatment for recurrence, the number of patients with lymph node, hematogeneous, mixed and local recurrence was 11, 6, 6 and 1, respectively. The number of lesions in hematogeneous recurrence was 2 or less. The survival rate from recurrence to death in the C, R, S and N groups was 0, 3.9, 6.7 and 0%, respectively. A statistically significant difference was found in these groups (p < 0.0001). CONCLUSIONS: Salvage surgery is one of the useful treatment tools for resectable metastatic lesions. In such cases, the number of lesions, recurrent sites and effectiveness of chemotherapy and/or radiotherapy should be carefully evaluated.