An iron-based beverage, HydroFerrate fluid (MRN-100), alleviates oxidative stress in murine lymphocytes in vitro

BackgroundSeveral studies have examined the correlation between iron oxidation and H2O2 degradation. The present study was carried out to examine the protective effects of MRN-100 against stress-induced apoptosis in murine splenic cells in vitro. MRN-100, or HydroFerrate fluid, is an iron-based beverage composed of bivalent and trivalent ferrates.MethodsSplenic lymphocytes from mice were cultured in the presence or absence of MRN-100 for 2 hrs and were subsequently exposed to hydrogen peroxide (H2O2) at a concentration of 25 μM for 14 hrs. Percent cell death was examined by flow cytometry and trypan blue exclusion. The effect of MRN-100 on Bcl-2 and Bax protein levels was determined by Western blot.ResultsResults show, as expected, that culture of splenic cells with H2O2 alone results in a significant increase in cell death (apoptosis) as compared to control (CM) cells. In contrast, pre-treatment of cells with MRN-100 followed by H2O2 treatment results in significantly reduced levels of apoptosis. In addition, MRN-100 partially prevents H2O2-induced down-regulation of the anti-apoptotic molecule Bcl-2 and upregulation of the pro-apoptotic molecule Bax.ConclusionOur findings suggest that MRN-100 may offer a protective effect against oxidative stress-induced apoptosis in lymphocytes

Arsenic Trioxide Exerts Antimyeloma Effects by Inhibiting Activity in the Cytoplasmic Substrates of Histone Deacetylase 6

Arsenic trioxide (As2O3) has shown remarkable efficacy for the treatment of multiple myeloma (MM). Histone deacetylases (HDAC) play an important role in the control of gene expression, and their dysregulation has been linked to myeloma. Especially, HDAC6, a unique cytoplasmic member of class II, which mainly functions as α-tubulin deacetylase and Hsp90 deacetylase, has become a target for drug development to treat cancer due to its major contribution in oncogenic cell transformation. However, the mechanisms of action for As2O3 have not yet been defined. In this study, we investigated the effect of As2O3 on proliferation and apoptosis in human myeloma cell line and primary myeloma cells, and then we studied that As2O3 exerts antimyeloma effects by inhibiting activity in the α-tubulin and Hsp90 through western blot analysis and immunoprecipitation. We found that As2O3 acts directly on MM cells at relatively low concentrations of 0.5∼2.5 µM, which effects survival and apoptosis of MM cells. However, As2O3 inhibited HDAC activity at the relatively high concentration and dose-dependent manner (great than 4 µM). Subsequently, we found that As2O3 treatment in a dose- and time-dependent fashion markedly increased the level of acetylated α-tubulin and acetylated Hsp90, and inhibited the chaperone association with IKKα activities and increased degradation of IKKα. Importantly, the loss of IKKα-associated Hsp90 occurred prior to any detectable loss in the levels of IKKα, indicating a novel pathway by which As2O3 down-regulates HDAC6 to destabilize IKKα protein via Hsp90 chaperone function. Furthermore, we observed the effect of As2O3 on TNF-α-induced NF-κB signaling pathway was to significantly reduced phosphorylation of Ser-536 on NF-κB p65. Therefore, our studies provide an important insight into the molecular mechanism of anti-myeloma activity of As2O3 in HDAC6-Hsp90-IKKα-NFκB signaling axis and the rationale for As2O3 can be extended readily using all the HDAC associated diseases

Patient-derived glioblastoma cells show significant heterogeneity in treatment responses to the inhibitor-of-apoptosis-protein antagonist birinapant.

BACKGROUND: Resistance to temozolomide (TMZ) greatly limits chemotherapeutic effectiveness in glioblastoma (GBM). Here we analysed the ability of the Inhibitor-of-apoptosis-protein (IAP) antagonist birinapant to enhance treatment responses to TMZ in both commercially available and patient-derived GBM cells. METHODS: Responses to TMZ and birinapant were analysed in a panel of commercial and patient-derived GBM cell lines using colorimetric viability assays, flow cytometry, morphological analysis and protein expression profiling of pro- and antiapoptotic proteins. Responses in vivo were analysed in an orthotopic xenograft GBM model. RESULTS: Single-agent treatment experiments categorised GBM cells into TMZ-sensitive cells, birinapant-sensitive cells, and cells that were insensitive to either treatment. Combination treatment allowed sensitisation to therapy in only a subset of resistant GBM cells. Cell death analysis identified three principal response patterns: Type A cells that readily activated caspase-8 and cell death in response to TMZ while addition of birinapant further sensitised the cells to TMZ-induced cell death; Type B cells that readily activated caspase-8 and cell death in response to birinapant but did not show further sensitisation with TMZ; and Type C cells that showed no significant cell death or moderately enhanced cell death in the combined treatment paradigm. Furthermore, in vivo, a Type C patient-derived cell line that was TMZ-insensitive in vitro and showed a strong sensitivity to TMZ and TMZ plus birinapant treatments. CONCLUSIONS: Our results demonstrate remarkable differences in responses of patient-derived GBM cells to birinapant single and combination treatments, and suggest that therapeutic responses in vivo may be greatly affected by the tumour microenvironment

Clinical guidelines for treating caries in adults following a minimal intervention policy?Evidence and consensus based report

Objectives: In 2002, FDI (World Dental Federation) published a policy advocating that caries be treated by minimal intervention (MI). This MI policy has been accepted worldwide and is taught in universities. But acceptance in general dental practice has been slower, especially in Japan where healthcare payment and practice favour drilling and filling. To help disseminate this MI policy into general practice, the Japanese Society of Conservative Dentistry developed an evidence-based clinical guideline for restoring carious permanent teeth in adult patients. Methods: The guideline was developed by a committee of nine university clinicians and a librarian. The committee selected the most frequent clinical questions in treating caries and used electronic databases to search and assess the best scientific evidence for each. Members then added their clinical experience and discussed to reach consensus on each question on treating caries with MI policy. Graded recommendations and guidance were made for each clinical question. The provisional guideline was strengthened after review and discussion with university researchers and general practitioners. Results: The guideline addresses the 16 most frequent clinical questions in treating adult caries, including restorative methods and how to tackle root caries. Recommendations for treatment using MI policy were developed using the best scientific evidence and consensus of experienced clinicians. Clinical significance: The guideline offers a practical expert view of treating caries with the MI policy that incorporates the best scientific evidence, the latest techniques, the most preferable materials and the general consensus of expert clinicians