Potentiation of Anticancer Activity of G2/M Blockers by Mild Hyperthermia.

BACKGROUND/AIM: Hyperthermia (HT), combined with chemotherapy, has been used to treat various types of cancer. This study aimed to investigate the HT-sensitivity of malignant and non-malignant cells, and then evaluate the combination effect of docetaxel (DTX) and a newly synthesized chromone derivative (compound A) with HT. MATERIALS AND METHODS: The number of viable cells was determined using the MTT method. Cell cycle distribution was analyzed using a cell sorter, and DNA fragmentation pattern was detected using agarose gel electrophoresis. RESULTS: Among 12 cultured cells, oral squamous cell carcinoma (OSCC), especially Ca9-22 cells, and myelogenous leukemia cells showed higher sensitivity to HT than lung carcinoma and glioblastoma cell lines, while normal oral cells were the most resistant. Cytotoxicity of DTX on Ca9-22 cells was maximum at 41-42°C and 45~60 min exposure to HT. DXT, compound A, and HT induced G2/M arrest of Ca-22 cells. Mild HT enhanced the DTX- and compound A-induced subG1 arrest, in a synergistic fashion. CONCLUSION: The combination G2/M blockers and mild-HT can potentially be used for the treatment of OSCC.

Extracellular Spermine Activates DNA Methyltransferase 3A and 3B.

We first demonstrated that long-term increased polyamine (spermine, spermidine, putrescine) intake elevated blood spermine levels in mice and humans, and lifelong consumption of polyamine-rich chow inhibited aging-associated increase in aberrant DNA methylation, inhibited aging-associated pathological changes, and extend lifespan of mouse. Because gene methylation status is closely associated with aging-associated conditions and polyamine metabolism is closely associated with regulation of gene methylation, we investigated the effects of extracellular spermine supplementation on substrate concentrations and enzyme activities involved in gene methylation. Jurkat cells and human mammary epithelial cells were cultured with spermine and/or D,L-alpha-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase. Spermine supplementation inhibited enzymatic activities of adenosylmethionine decarboxylase in both cells. The ratio of decarboxylated S-adenosylmethionine to S-adenosyl-L-methionine increased by DFMO and decreased by spermine. In Jurkat cells cultured with DFMO, the protein levels of DNA methyltransferases (DNMTs) 1, 3A and 3B were not changed, however the activity of the three enzymes markedly decreased. The protein levels of these enzymes were not changed by addition of spermine, DNMT 3A and especially 3B were activated. We show that changes in polyamine metabolism dramatically affect substrate concentrations and activities of enzymes involved in gene methylation.

Recent Progress of Basic Studies of Natural Products and Their Dental Application.

The present article reviews the research progress of three major polyphenols (tannins, flavonoids and lignin carbohydrate complexes), chromone (backbone structure of flavonoids) and herbal extracts. Chemical modified chromone derivatives showed highly specific toxicity against human oral squamous cell carcinoma cell lines, with much lower toxicity against human oral keratinocytes, as compared with various anticancer drugs. QSAR analysis suggests the possible correlation between their tumor-specificity and three-dimensional molecular shape. Condensed tannins in the tea extracts inactivated the glucosyltransferase enzymes, involved in the biofilm formation. Lignin-carbohydrate complexes (prepared by alkaline extraction and acid-precipitation) and crude alkaline extract of the leaves of Sasa species (SE, available as an over-the-counter drug) showed much higher anti-HIV activity, than tannins, flavonoids and Japanese traditional medicine (Kampo). Long-term treatment with SE and several Kampo medicines showed an anti-inflammatory and anti-oxidant effects in small size of clinical trials. Although the anti-periodontitis activity of synthetic angiotensin II blockers has been suggested in many papers, natural angiotensin II blockers has not yet been tested for their possible anti-periodontitis activity. There should be still many unknown substances that are useful for treating the oral diseases in the natural kingdom.

Future expectations for Japanese pharmacists as compared to the rest of the world.

It is important to share information about other countries' pharmacists to optimize cross-border medical cooperation. This paper examines the dispensing systems and the work done by pharmacists in the United Kingdom, Germany, France, Thailand, and Malaysia so as to compare these countries' medical practices and develop a cohesive vision for the future of Japanese pharmacists. All five of the countries have dispensing assistants. Pharmacists in Japan have duties of inventory control, drug dispensing, and providing medication advice. In contrast, assistants working in other countries are responsible for some aspects of dispensing and inventory control, allowing the pharmacists to spend their time and competency in instructing patients on how to take their medication. Because of this, pharmacists were actively involved with health promotion intervention in the United Kingdom, Germany, and France. It is hoped that work done by Japanese pharmacists would transition from primarily dispensing drugs to patient care, advice, and counseling to enrich overall health promotion and health/nutrition counseling.

Long-term oral polyamine intake increases blood polyamine concentrations.

Although the intracellular de novo synthesis of the polyamines decreases with age, there is no similar trend in blood polyamine levels, but rather there is wide individual variability. We hypothesized that dietary polyamines attenuate a decrease in blood polyamine levels with age and augment the previously observed individual variability. The effect of a polyamine rich diet, in both mice and humans, on blood polyamine concentrations was examined in this study. Jc1:ICR male mice were fed test diets containing 3 different polyamine concentrations. Healthy human male volunteers added 50 to 100 g of the polyamine-rich fermented soybean product, natto, to their daily intake. After 26 wk, the mean blood spermine concentration in mice receiving the test diet with high polyamine concentrations was 10.1+/-2.4 micromol/L, while the mean concentrations found in mice fed with a diet with normal or low polyamine concentrations were 5.2+/-0.9 and 4.7+/-0.5 micromol/L, respectively (p<0.05). A mean daily intake of 66.4+/-3.7 g (range=46.4-89.3 g) of natto for 2 mo by human volunteers increased the mean blood spermine concentration by a factor of 1.39 (n=10) (p<0.01), while in control volunteers (n=7), asked to exclude polyamine-rich foods from their diet, blood spermine concentration remained unchanged. The individual variability of blood polyamine levels was enhanced after polyamine intake in mice and, to a lesser extent, in humans. The long-term oral intake of enhanced polyamine diets increases blood polyamine levels in both mice and humans.