nNav1.5 expression is associated with glutamate level in breast cancer cells

Abstract Background: Glutamate and voltage-gated sodium channels, both have been the target of intense investigation for its involvement in carcinogenesis and progression of malignant disease. Breast cancer with increased level of glutamate often metastasize to other organs (especially bone), whilst re-expression of 'neonatal' Nav1.5, nNav1.5 in breast cancer is known to promote cell invasion in vitro, metastasis in vivo and positive lymph node metastasis in patients. Methods: In this study, the role of nNav1.5 in regulating glutamate level in human breast cancer cells was examined using pharmacological approach (VGSCs specific blocker, TTX, glutamate release inhibitor, riluzole and siRNA-nNav1.5). Effect of these agents were evaluated based on endogenous and exogenous glutamate concentration using glutamate fluorometric assay, mRNA expression of nNav1.5 using qPCR and finally, invasion using 3D culture assay. Results: Endogenous and exogenous glutamate levels were significantly higher in aggressive human breast cancer cells, MDA-MB-231 cells compared to less aggressive human breast cancer cells, MCF-7 and non-cancerous human breast epithelial cells, MCF-10A. Treatment with TTX to MDA-MB-231 cells resulted in significant reduction of endogenous and exogenous glutamate levels corresponded with significant suppression of cell invasion. Subsequently, downregulation of nNav1.5 gene was observed in TTX-treated cells. Conclusions: An interesting link between nNav1.5 expression and glutamate level in aggressive breast cancer cells was detected and requires further investigation.

Effect of normabaric hyperoxia treatment on neuronal damage following fluid percussion injury in the striatum of mice: A morphological approach.

Traumatic brain injury (TBI) causes significant mortality in most developing countries worldwide. At present, it is imperative to identify a treatment to address the devastating post-TBI consequences. Therefore, the present study has been performed to assess the specific effect of immediate exposure to normabaric hyperoxia (NBO) after fluid percussion injury (FPI) in the striatum of mice. To execute FPI, mice were anesthetised and sorted into (i) a TBI group, (ii) a sham group without injury and (iii) a TBI group treated with immediate exposure to NBO for 3 h. Afterwards, brains were harvested for morphological assessment. The results revealed no changes in morphological and neuronal damage in the sham group as compared to the TBI group. Conversely, the TBI group showed severe morphological changes as well as neuronal damage as compared to the TBI group exposed to NBO for 3 h. Interestingly, our findings also suggested that NBO treatment could diminish the neuronal damage in the striatum of mice after FPI. Neuronal damage was evaluated at different points of injury and the neighbouring areas using morphology, neuronal apoptotic cell death and pan-neuronal markers to determine the complete neuronal structure. In conclusion, immediate exposure to NBO following FPI could be a potential therapeutic approach to reduce neuronal damage in the TBI model.

Association of Mitochondrial DNA 10398 Polymorphism in Invasive Breast Cancer in Malay Population of Peninsular Malaysia

Background: The mitochondrial DNA (mtDNA) 10398 polymorphism is hypothesised to alter a mitochondrial subunit of the electron transfer chain and is associated with several neurodegenerative disorders and cancers. Methods: In this study, an mtDNA polymorphism at nucleotide position 10398 was screened in 101 Malay female patients with invasive breast cancer and 90 age-matched healthy female controls using minisequencing analysis. Results: The Malay women with the 10398G variant showed a significantly increased risk of invasive breast cancer (OR = 2.29, 95% CI 1.25–4.20, P = 0.007). Immunohistochemistry analysis was conducted to investigate the effect of this polymorphism on the levels of apoptosis in breast cancer cells. The level of Bax (a pro-apoptotic protein) expression was significantly higher than that of Bcl-2 (an anti-apoptotic protein) in patients carrying the G allele (P = 0.016) but not in those carrying the A allele (P = 0.48). Conclusion: Based on these findings, we propose that the mtDNA 10398 polymorphism may be a potential risk marker for breast cancer susceptibility in the Malay population.

Lymphatic channel density in colorectal adenocarcinoma.

Aims : The purpose of this study was to count the number of lymphatic channels present in colorectal adenocarcinoma and correlate it with site, size, and stage of tumor, lymph node metastasis. Material and Methods: A total of 29 cases of colorectal carcinomas were retrieved from the archives of the pathology department, School of Medical Sciences. One paraffin block containing tumor was selected from each case. Sections of three to five micron thickness were cut from this paraffin block and stained using the monoclonal antibody D2-40[DAKO] specifically to stain lymphatic channel endothelium in normal and neoplastic tissue. The highest number of lymphatic channels in an area of 0.196mm 2 [high power field] was counted in each tumor using NIKON microscope. These findings were correlated with the clinical parameters and also with lymph node metastasis. Statistical software used: SPSS version 11. Results : The highest density of lymphatic channels in colorectal carcinoma was counted after identifying the appropriate "hot spot". The lymphatic channel density was in the range of 15 - 50/ 0.196 mm 2 [high power field]. There was poor association of this lymphatic channel density with site, size, and stage of tumor and also with lymph node metastasis. This result is in concordance with results of studies done elsewhere. Conclusion : In this study no significant association was seen between lymphatic channel density and site, size, stage and lymph node metastasis in colorectal carcinoma. This indicates that lymphatic channel proliferation does not influence tumor aggressiveness. Further studies are needed to validate our findings.