Nitric Oxide-Induced Apoptosis of Human Dental Pulp Cells Is Mediated by the Mitochondria-Dependent Pathway

Nitric oxide (NO) is recognized as a mediator and regulator of inflammatory responses. NO is produced by nitric oxide synthase (NOS), and NOS is abundantly expressed in the human dental pulp cells (HDPCs). NO produced by NOS can be cytotoxic at higher concentrations to HDPCs. However, the mechanism by which this cytotoxic pathway is activated in cells exposed to NO is not known. The purpose of this study was to elucidate the NO-induced cytotoxic mechanism in HDPCs. Sodium nitroprusside (SNP), a NO donor, reduced the viability of HDPCs in a dose- and time-dependent manner. We investigated the in vitro effects of nitric oxide on apoptosis of cultured HDPCs. Cells showed typical apoptotic morphology after exposure to SNP. Besides, the number of Annexin V positive cells was increased among the SNP-treated HDPCs. SNP enhanced the production of reactive oxygen species (ROS), and N-acetylcysteine (NAC) ameliorated the decrement of cell viability induced by SNP. However, a soluble guanylate cyclase inhibitor (ODQ) did not inhibited the decrement of cell viability induced by SNP. SNP increased cytochrome c release from the mitochondria to the cytosol and the ratio of Bax/Bcl-2 expression levels. Moreover, SNP-treated HDPCs elevated activities of caspase-3 and caspase-9. While pretreatment with inhibitors of caspase (z-VAD-fmk, z-DEVD-fmk) reversed the NO-induced apoptosis of HDPCs. From these results, it can be suggested that NO induces apoptosis of HDPCs through the mitochondria-dependent pathway mediated by ROS and Bcl-2 family, but not by the cyclic GMP pathway.

The Relatioships Between Tumor-related Gene Expression and Tumor Budding, Tumor Nodule and Lymph Node Extracapsular Extension in Colorectal Cancer

PURPOSE: Despite the similar lymph node metastasis observed in patients with advanced colorectal cancer (CRC), there was a different clinical outcome. The relationships between tumor-related gene expression and prognostic factors such as tumor budding, tumor nodule and extracapsular extension (ECE) of lymph nodes in patients with CRC remain unclear yet. The purpose of this study was to evaluate the relationship between expression of molecular markers such as vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), matrix metalloproteinases (MMPs) and E-cadherin and the tumor budding, tumor nodule and ECE of lymph nodes in patients with stage III CRC. METHODS: The tissue of 87 patients with stage III CRC were investigated for expressions of molecular markers using immunohistochemical methods. RESULTS: VEGF and MMP-9 expression in tumor tissue were positively associated with the colorectal cancer prognostic factors such as tumor budding, tumor nodule and extracapsular lymph node extension (P<0.05). But, MMP-2, EGF and E-cadherin expression were of no value with regard to them. CONCLUSION: Our results suggest that molecular markers, in particular VEGF and MMP-9, may provide additional prognostic information regarding tumor budding, ECE and tumor nodule.

Correlation between the Expression of Nuclear Factor-kappaB p65 Protein with the Expression of Nuclear Factor-kappaB p50 Protein and the Clinicopathologic Factors in Colorectal Cancer

PURPOSE: Nuclear Factor-kappaB p65 (NF-kappaB p65) and nuclear Factor-kappaB1 p50 (NF-kappaB p65) have been shown to play roles in cell proliferation, apoptosis, cytokine production and oncogenesis. This study was designed to investigate the expressions of NF-kappaB p65 and NF-kappaB p50 proteins in premalignant lesions and colorectal adenocarcinoma. METHODS: Paraffin sections of 20 normal mucosa specimens, 20 low grade tubular adenoma specimens, 20 high grade tubular adenoma specimens and 64 adenocarcinoma specimens were analyzed immunohistochemically for the expressions of NF-kappaB p65 and NF-kappaB p50 proteins. RESULTS: The expressions of NF-kappaB p65 and NF-kappaB p50 proteins were significantly higher in the adenocarcinoma tissue compared with that in the normal mucosa, the low grade tubular adenoma and the high grade tubular adenoma tissues. The frequency of a NF-kappaB p50 expression was higher in the poorly differentiated histologic grade specimens, in the presence of nodal metastasis and in the high stage specimens. There were significant correlations between the NF-kappaB p65 and NF-kappaB p50 proteins. CONCLUSION: The expressions of NF-kappaB p65 and NF-kappaB p50 proteins may play a role in the pathogenesis of colorectal carcinoma.

The Influence of Expressions of Cyclin B1 and D1 on Clinicopathologic Prognostic Factors and Survival Rate in Gastric Cancer

PURPOSE: Disturbance in normal cell cycles by cell cycle control factors is an important process of cancer carcinogenesis. The aims of this dissertation were identify the influence of cyclin B1 and D1 on the growth and expression of gastric cancer and their effects on the prognosis. METHOD: The subjects were 128 patients selected from those who underwent gastric surgery for their gastric cancer between January 1995 and December 1998. Immunohistochemical staining was conducted for cyclin B1 and D1 using paraffin embedded tissues, followed by analysis of their protein expressions, possible prognostic factors and survival rate. RESULTS: Cyclin B1 expression was founded in 48 of the 128 patients (37.5%), and that of cyclin D1 in 96 (75%). Both cyclin B1 and D1 showed no statistical significance with T-stage, location of tumors or histologic types. However, for the case of any significance with lymph node metastasis, the higher the N-stage, the greater was the expression of cyclin B1 (P=0.014). For the case of any significance with life term, the Kaplan-Meier method showed the greater the expression of cyclin B1, the shorter the life term (P=0.042). CONCLUSION: An association was indicated between cyclin B1 and lymph node metastasis in gastric cancer, but has no relation with the T-stage, histologic type or location of tumors. Cyclin D1 shows no association with lymph node metastasis, T-stage, histologic type or location of tumors. However, cyclin B1 showed a significant association with the survival rate.