The study of isotopic enrichment of water in human plasma and erythrocyte.

Life does not sustain without water. For water, there is a natural abundance of stable isotope hydrogen and oxygen. Water molecules get across cell membranes through a plasma membrane protein, named aquaporin. Moreover, the kidney is the main organ to maintain water homeostasis. Here, we study the stable isotopic ratios of hydrogen and oxygen in human blood plasma and erythrocyte corresponding to kidney functions. We extract waters from human plasma and erythrocyte, collected from 110 participants, including 51 clinically stable outpatients with end-stage renal disease (ESRD) and 59 subjects with normal renal function (NRF). We observed that (i) both extracellular (blood plasma) and intracellular (erythrocyte) biology waters are isotopic differences between the ESRD and NRF participants, (ii) the natural abundance of isotopic waters of ESRD is hypo-isotopic, and (iii) the isotopic enrichment of water between erythrocyte and blood plasma are distinct. In addition, we introduce an empirical formula using entropy transformation to describe isotopic water enrichment for biology. Accordingly, the natural abundance of stable isotope water of blood plasma and erythrocyte may be possibly put in practice a new sign for assessments of kidney dysfunctions.

Active and stable liquid water innovatively prepared using resonantly illuminated gold nanoparticles.

The properties of confined liquid water, or liquid water in contact with hydrophobic surfaces, are significantly different from those of bulk liquid water. However, all of water's commonly described properties are related to inert "bulk liquid water" which comprises a tetrahedral hydrogen-bonded network. In this work, we report an innovative and facile method for preparing small water clusters (SWCs) with reduced affinity hydrogen bonds by letting bulk water flow through supported Au nanoparticles (NPs) under resonant illumination to give NP-treated (AuNT) water at constant temperature. Utilizing localized surface plasmon resonance on illuminated Au NPs, the strong hydrogen bonds of bulk water can be disordered when water is located at the illuminated Au/water interface. The prepared SWCs are free of Au NPs. The energy efficiency for creating SWCs is ∼17%. The resulting stable AuNT water exhibits distinct properties at room temperature, which are significantly different from the properties of untreated bulk water, examples being their ability to scavenge free hydroxyl and 2,2-diphenyl-1-picrylhydrazyl radicals and to effectively reduce NO release from lipopolysaccharide-induced inflammatory cells.

Assessment of renal function by the stable oxygen and hydrogen isotopes in human blood plasma.

Water (H(2)O) is the most abundant and important molecule of life. Natural water contains small amount of heavy isotopes. Previously, few animal model studies have shown that the isotopic composition of body water could play important roles in physiology and pathophysiology. Here we study the stable isotopic ratios of hydrogen (δ(2)H) and oxygen (δ(18)O) in human blood plasma. The stable isotopic ratio is defined and determined by δ(sample) = [(R(sample)/R(STD))-1] * 1000, where R is the molar ratio of rare to abundant, for example, (18)O/(16)O. We observe that the δ(2)H and the δ(18)O in human blood plasma are associated with the human renal functions. The water isotope ratios of the δ(2)H and δ(18)O in human blood plasma of the control subjects are comparable to those of the diabetes subjects (with healthy kidney), but are statistically higher than those of the end stage renal disease subjects (p<0.001 for both ANOVA and Student's t-test). In addition, our data indicate the existence of the biological homeostasis of water isotopes in all subjects, except the end stage renal disease subjects under the haemodialysis treatment. Furthermore, the unexpected water contents (δ(2)H and δ(18)O) in blood plasma of body water may shed light on a novel assessment of renal functions.

Synthesis and antitumor evaluation of novel bis-triaziquone derivatives.

Aziridine-containing compounds have been of interest as anticancer agents since late 1970s. The design, synthesis and study of triaziquone (TZQ) analogues with the aim of obtaining compounds with enhanced efficacy and reduced toxicity are an ongoing research effort in our group. A series of bis-type TZQ derivatives has been prepared and their cytotoxic activities were investigated. The cytotoxicity of these bis-type TZQ derivatives were tested on three cancer lines, including breast cancer (BC-M1), oral cancer (OEC-M1), larynx epidermal cancer (Hep2) and one normal skin fibroblast (SF). Most of these synthetic derivatives displayed significant cytotoxic activities against human carcinoma cell lines, but weak activities against SF. Among tested analogues the bis-type TZQ derivative 1a showed lethal effects on larynx epidermal carcinoma cells (Hep2), with an LC(50) value of 2.02 microM, and also weak cytotoxic activity against SF cells with an LC(50) value over 10 microM for 24 hr treatment. Comparing the viability of normal fibroblast cells treated with compound 1a and TZQ, the LC(50) value of the latter was 2.52 microM, indicating more toxicity than compound 1a. This significantly decreased cytotoxicity of compound 1a towards normal SF cells, while still maintaining the anticancer activity towards Hep2 cells is an interesting feature. Among the seven compounds synthesized, compound 1c has similar toxicity effects on the three cancer cell lines and SF normal cells as the TZQ monomer.

Antitumor activity of a novel bis-aziridinylnaphthoquinone (AZ4) mediating cell cycle arrest and apoptosis in non-small cell lung cancer cell line NCI-H460.

AIM: The cytotoxic activities of a series of bis-aziridinylnaphthoquinone, AZ1 to AZ4, on human lung carcinoma cell lines, H460, and normal lung cells fibroblast cell line, MRC-5, and the mechanisms of H460 cells induced by AZ4 were investigated. METHODS: The MTT assay was used to determine the cell proliferation. Cell cycle was analysed by FACS. The activity of caspase 3, 8 and 9 was determined by cell-permeable fluorogenic detection system. Western blot assay was used to evaluate the regulation of cyclin B, Cdc-2, p53, p21, and the Bcl-2 protein. RESULTS: AZ1 to AZ4 displayed various cytotoxicity activities against H460 and MRC-5 cells. Compared to those compounds, AZ4 was with the most effective agent among the 5 tested analogues at reducing H460 cell viability with an IC(50) value of 1.23 micromol/L; it also exhibited weak cytotoxicity against MRC-5 cells with an IC(50) value of 12.7 micromol/L. The results show that growth arrest on the G2-M phase of H460 cells induced by AZ4 for 24 h was discovered, and this might be altered with the reduced Cdc-2 protein expression of 47% at 2.0 micromol/L AZ4, but not with cyclin B protein expression. The AZ4 treated cells were then led to apoptosis after 48 h. This was associated with the activation of apoptotic enzyme caspase 3 and mediated by caspase 8, but not caspase 9 at various concentrations of AZ4 after being cultured for 48 h and 30 h, respectively. The anti-apoptotic protein (Bcl-2) expression in H460 cells altered by 39% with downregulation, and the p53 protein by 25% with upregulation after being cultured with 2.0 micromol/L AZ4 for 48 h. In a time-dependent manner, the expression of the p53 and p21 proteins were increased to the maximum at 24 h, and then decreased at 48. CONCLUSION: AZ4 represents a novel antitumor aziridinylnaphthoquinone with therapeutic potential against the non-small cell lung cancer cells.

The lethal effect of bis-type azridinylnaphthoquinone derivative on oral cancer cells (OEC-M1) associated with anti-apoptotic protein bcl-2.

Several drugs of aziridinylbenzoquinone analogs have undergone clinical trials as potential antitumor drugs. These bioreductive compounds are designed to kill tumor cells preferentially within the hypoxic microenvironment. From our previous reported data, it was found that the synthesized 2-aziridin-1-yl-3-[(2-[2-[(3-aziridin-1-yl-1,4-dioxo-1,4-dihydronaphthalen-2-yl)thio]ethoxy]ethyl)thio]naphthoquinone (AZ-1) is a bioreductive compound with potent lethal effect on oral cancer cell, OEC-M1. It was found in this study that the lethal effect of the oral cancer cell lines OEC-M1 induced by AZ-1 was mediated through the cell cycle arrest and apoptosis pathway. The LC50 values of OEC-M1 and KB cells induced by AZ-1 compound were 0.72 and 1.02 microM, respectively, which were much lower than that of normal fibroblast cells (SF with LC50 = 5.6 microM) with more than 90% of normal fibroblasts surviving as compared to control at a concentration of AZ-1 as high as 2 microM. It was interesting to note that the LC50 of monotype diaziridinylbenzoquinone compound, diaziquone (AZQ), was 50 microM on OEC-M1 cells. Comparing the cytotoxicity of AZ-1 and AZQ on OEC-M1 cells, AZ-1 is approximately 70 times more potent than AZQ. By using Western blot, both G2/M phase cell cycle arresting protein, cyclin B, and anti-apoptotic protein, bcl-2, were expressed in OEC-M1 cell when the concentrations of AZ-1 were increased from 0.125 to 0.5 microM and then decreased from 1 to 2 microM of AZ-1 treatment as compared with control for 24 h. Both proteins were expressed most abundantly at 0.5 microM AZ-1. However, the expression of bcl-2 protein in OEC-M1 was significantly decreasing in a dose-dependent manner and was only about 50% protein level at 2 microM AZ-1 for 48h as compared with control. The cell survival check protein p53 increased from 1.72- to 2.8-fold and 1.36- to 2.16-fold at concentrations of AZ-1 from 0.125 to 2.0 microM in a dose-dependently increasing manner on OEC-M1 as compared with control for 24 and48 h treatments, respectively. The apoptotic-related phenomena were observed, which included apoptotic body formation and the enzyme activity change of caspase-3. The apoptotic bodies and caspase-3 activity of OEC-M1 were induced only at 2 microM AZ-1 for a 24h treatment, yet apoptotic body formation was observed at as low as 0.5 microM AZ-1 and in a dose-dependently increasing manner for a 48 h treatment. The caspase-3 activity was increased 20.6%, 26.8%, and 84.2%, respectively, at 0.5, 1, and 2muM concentrations of AZ-1 for a 48 h treatment as compared with control. These results indicate that AZ-1 induced the cell death of OEC-M1 through the G2/M phase arrest of cell cycle and anti-apoptosis first and then apoptosis following a 48 h treatment. All of the pathway might be associated with bcl-2 and p53 protein expression. We propose that the AZ-1 could be used as anti-oral cancer drug for future studies with animal models.

The p53-dependent apoptotic pathway of breast cancer cells (BC-M1) induced by the bis-type bioreductive compound aziridinylnaphthoquinone.

INTRODUCTION: Several aziridinylbenzoquinone drugs have undergone clinical trials as potential antitumor drugs. These bioreductive compounds are designed to kill cells preferentially within the hypoxia tumor microenvironment. The bioreductive compound of bis-type naphthoquinone synthesized in our laboratory, 2-aziridin-1-yl-3-[(2-{2-[(3-aziridin-1-yl-1,4-dioxo-1,4-dihydronaphthalen-2-yl)thio]ethoxy}ethyl)thio]naphthoquinone (AZ-1), had the most potent death effect on the breast cancer cells BC-M1 in our previous screening. In the present study, we determined that the mechanism of the death effect of BC-M1 cells induced by AZ-1 was mediated by the apoptosis pathway. METHODS: We evaluated the cytotoxicity of AZ-1 and the anti-breast cancer drugs tamoxifen and paclitaxel to BC-M1 cells and MCF-7 cells by the MTT assay and measured the apoptosis phenomena by Hoechst 33258 staining for apoptotic bodies. We also quantified the sub-G1 peak area and the ratio of the CH2/CH3 peak area of the cell membrane in BC-M1 cells by flow cytometry and 1H-NMR spectra, respectively. The apoptosis-related protein expressions, including p53, p21, the RNA-relating protein T-cell restricted intracellular antigen-related protein, cyclin-dependent kinase 2 (cell cycle regulating kinase) and pro-caspase 3, were detected by western blot, and the caspase-3 enzyme activity was also quantified by an assay kit. RESULTS: AZ-1 induced two of the breast cancer cell lines, with IC50 = 0.51 microM in BC-M1 cells and with IC50= 0.57 microM in MCF-7 cells, and showed less cytotoxicity to normal fibroblast cells (skin fibroblasts) with IC50= 5.6 microM. There was a 10-fold difference between two breast cancer cell lines and normal fibroblasts. Of the two anti-breast cancer drugs, tamoxifen showed IC50= 0.12 microM to BC-M1 cells and paclitaxel had much less sensitivity than AZ-1. The expression of p53 protein increased from 0.5 to 1.0 microM AZ-1 and decreased at 2.0 microM AZ-1. The p21 protein increased from 0.5 microM AZ-1, with the highest at 2 microM AZ-1. Regarding the AZ-1 compound-induced BC-M1 cells mediating the apoptosis pathway, the apoptotic body formation, the sub-G1 peak area, the ratio of CH2/CH3 of phospholipids in the cell membrane and the enzyme activity of caspase-3 were all in direct proportion with the dose-dependent increase of the concentration of AZ-1. The death effect-related proteins, including T-cell restricted intracellular antigen-related protein, cyclin-dependent kinase 2, and pro-caspase-3, all dose-dependently decreased with AZ-1 concentration. CONCLUSIONS: The AZ-1-induced cell death of BC-M1 cells mediating the apoptosis pathway might be associated with p53 protein expression, and AZ-1 could have the chance to be a candidate drug for anti-breast cancer following more experimental evidence, such as animal models.

A novel bis-aziridinylnaphthoquinone with anti-solid tumor activity in which induced apoptosis is associated with altered expression of Bcl-2 protein.

Aziridine-containing compounds have been of interest as anticancer agents since the late 1970s. The design, synthesis, and study of aziridinylnaphthoquinone analogues to obtain compounds with enhanced activity/toxicity profiles are an ongoing research effort in our group. A series of bis-aziridinylnaphthoquinone derivatives has been prepared, and the cytotoxic activities of these synthetic bis-aziridinylnaphthoquinone derivatives has been investigated. The synthetic derivatives displayed significant cytotoxicity against human carcinoma cell lines and weak cytotoxic activities against skin fibroblasts (SF). The bis-aziridinylnaphthoquinone 1 c was the most effective of the tested analogues at reducing the viability of Hep2 cells, with an LD(50) value of 5.23 microM, and also exhibited weak cytotoxic activity against SF cells, with an LD(50) value of 54.12 microM. The DNA alkylation and DNA interstrand cross-linking abilities of 1 c were also investigated. Bis-aziridinylnaphthoquinone 1 c was an effective agent for alkylation of DNA after chemical reduction in vitro, and its bifunctional alkylating moieties were able to cross-link DNA. We also report here our efforts to determine direct antitumor effects of 1 c on Hep2 cells. Growth arrest in Hep2 cells was preceded by early induction of G(2)-M cell cycle arrest at 0.75 microM of 1 c after culture for 24 h, and was then followed by apoptosis after 60 h. This was associated with decreased expression of antiapoptotic bcl2 protein (by 78 %) upon culture with 3.0 microM of 1 c after 60 h. Our results suggest that 1 c is a novel antitumor aziridinylnaphthoquinone with therapeutic potential against solid tumors.

Synthesis and biological evaluation of novel bis-aziridinylnaphthoquinone derivatives.

A series of bis-aziridinylnaphthoquinone derivatives has been prepared. The cytotoxic activities and DNA alkylation abilities of these synthetic bis-aziridinylnaphthoquinone derivatives were investigated. They displayed significant cytotoxicity against human carcinomna cell lines and weak cytotoxic activities against HL60 and skin fibroblast (SF). The bisaziridinylnaphthoquinone 1a was the most potent agent among those tested, with an LD50 value of 0.57 microM against the BC-M1 cell line. It exhibited the weakest activity against SF and HL60 with LD50 values of 5.67 and 20.1 microM, respectively, and it was able to alkylate DNA after chemical reduction in vitro. The analogues without aziridinyl moiety 2a and 3a lack DNA alkylation abilities.

Efficient synthesis of 'redox-switched' naphthoquinone thiol-crown ethers and their biological activity evaluation.

Series of naphthoquinone thiol-crown ethers had been prepared. The antibacterial, antifungal, and cytotoxic activities of these synthetic naphthoquinone thiol-crown ethers were investigated. All of the compounds tested displayed antibacterial, cytotoxic and antifungal activities. The bis-naphthoquinone thiol-crown ether 7a was the most potent inhibitor among tested analogues against Staphylococcus aureus methicillin resistance with MIC value of 2.68 microM.