Wirote Tuntiwechapikul

Ginger extract inhibits human telomerase reverse transcriptase and c-Myc expression in A549 lung cancer cells.

The rhizome of ginger (Zingiber officinale Roscoe) has been reputed to have many curative properties in traditional medicine, and recent publications have also shown that many agents in ginger possess anticancer properties. Here we show that the ethyl acetate fraction of ginger extract can inhibit the expression of the two prominent molecular targets of cancer, the human telomerase reverse transcriptase (hTERT) and c-Myc, in A549 lung cancer cells in a time- and concentration-dependent manner. The treated cells exhibited diminished telomerase activity because of reduced protein production rather than direct inhibition of telomerase. The reduction of hTERT expression coincided with the reduction of c-Myc expression, which is one of the hTERT transcription factors; thus, the reduction in hTERT expression might be due in part to the decrease of c-Myc. As both telomerase inhibition and Myc inhibition are cancer-specific targets for cancer therapy, ginger extract might prove to be beneficial as a complementary agent in cancer prevention and maintenance therapy.

Down-regulation of the human VEGF gene expression by perylene monoimide derivatives.

The proximal promoter region of the human vascular endothelial growth factor (VEGF) gene contains a guanine-rich strand that can act as a transcriptional silencer by forming an intramolecular G-quadruplex. In this study, we compared two perylene monoimide derivatives, PM1 and PM2, with the well-studied perylene diimide derivative, PIPER, and the well-studied porphyrin derivative, TmPyP(4), with regard to G-quadruplex formation, G-quadruplex binding selectivity, and human VEGF gene silencing in A549 lung cancer cells. The results show that these perylene derivatives can preferentially induce intramolecular G-quadruplex formation from a duplex containing the VEGF G-quadruplex motif in vitro. Incubating A549 lung cancer cells with these perylene derivatives, especially PM2, led to the reduction of both VEGF mRNA and VEGF protein. This study might provide the foundation for the rational design and development of new perylene derivatives as effective anti-angiogenesis agents for cancer therapy.

Curcuminoid derivatives enhance telomerase activity in an in vitro TRAP assay

The length of telomeres controls the life span of eukaryotic cells. Telomerase maintains the length of telomeres in certain eukaryotic cells, such as germline cells and stem cells, and allows these cells to evade replicative senescence. Here, we report for the first time a number of curcuminoid derivatives that enhance telomerase activity in an in vitro TRAP assay. A preliminary analysis of structure-activity relationships found that the minimal requirement for this enhanced telomerase activity is a curcuminoid core with at least one n-pentylpyridine side chain, while curcuminoids with two such side chains exhibit even greater activity. The finding here might lead to a new class of telomerase activators that act directly or indirectly on telomerase, rather than through the reactivation of the telomerase reverse transcriptase (TERT) gene associated with other telomerase activators found in the literature.

Aristolactam-type alkaloids from orophea enterocarpa and their cytotoxicities

A new aristolactam, named enterocarpam-III (10-amino-2,3,4,6-tetramethoxy phenanthrene-1-carboxylic acid lactam, 1) together with the known alkaloid stigmalactam (2), were isolated from Orophea enterocarpa. Their structures were elucidated on the basis of interpretation of their spectroscopic data. Compounds 1 and 2 exhibited significant cytotoxicities against human colon adenocarcinoma (HCT15) cell line with IC50 values of 1.68 and 1.32 μM, respectively.

Development of an ELISA strip for the detection of α thalassemias

α thalassemia is probably the most common of all single-gene disorders throughout the world. Most incidences of α thalassemia arise from the deletion of one (-α) or both (--) of the α globin genes, which are known as α+ thalassemia (-α/αα) or α thalassemia (--/αα), respectively.[1][1] The

Prevalence of α-thalassaemia genotypes in pregnant women in northern Thailand

Background & objectives: Alpha-thalassaemias are genetic disorders with high prevalence in northern Thailand. However, common genotypes and current data on the prevalence of α-thalassaemias have not been reported in this region. Therefore, the objective of the present study was to determine the prevalence of α-thalassaemia genotypes in pregnant women in northern Thailand. Methods: Genomic DNA was extracted from blood samples of pregnant women who came to Maharaj Nakorn Chiang Mai University Hospital during July 2009 to 2010. The common deletion and point mutation genotypes of α-thalassaemia were evaluated by gap- polymerase chain reaction (PCR) and PCR with restriction fragment length polymorphism (RFLP). Results: Genotypes of 638 pregnant women were: 409 samples (64.11%) being normal subjects (αα/αα) and 229 samples (35.89%) with α-thalassaemias. These 229 samples could be classified into deletional HbH disease (--SEA/-α3.7) for 18 samples (2.82%); heterozygous α0-thalassaemia --SEA type (--SEA/αα)) for 78 (12.23%); heterozygous α+-thalassaemia - α3.7 type (-α3.7/αα) for 99 (15.52%); homozygous α+-thalassaemia - α3.7 type (-α3.7/- α3.7) for five (0.78%); heterozygous α+-thalassaemia - α4.2 type (-α4.2/αα) for two (0.31%); and heterozygous HbCS (αCSα/αα) for 27 (4.23%) cases. Interpretation & conclusions: The prevalence of α-thalassaemias in pregnant women in northern Thailand was high. This finding supports the implementation of the prevention and control of this common genetic disorder by screening for α-thalassaemia genotypes.

Application of monoclonal and polyclonal antibodies to Hb Bart's for the detection of α thalassemias

Using a mouse monoclonal antibody (mAb) (“2D4”) with high specific reactivity to Hb Bart’s and a rabbit polyclonal antibody (“RPB”) with high reactivity to Hb Bart’s but low reactivity to HbF, an ELISA assay was developed for the quantification of Hb Bart’s in hemolysates of peripheral blood. In the preliminary study, hemoglobin solutions containing 4,000 μg/mL of hemoglobin were analyzed for the concentration of Hb Bart’s in samples collected from the following children and adult subjects of HbH families: 12 children with deletional HbH disease (--/3.7 ) or nondeletional HbH disease (HbH disease with HbCS) (--/ cs ), 12 adults with 0 thalassemia (--/ ), 12 adults with deletional or nondeletional + thalassemia (3.7 / or / cs ) and 12 normal adult subjects ( / ). The mean ± S.D. of Hb Bart’s concentration in those with deletional HbH disease or HbH disease with HbCS, 0 thalassemia, deletional or nondeletional + thalassemia, and normal subjects were 1,374±210 (range 1,164-1,584), 1,118±357 (range 761-1,475), 451 ± 230 (range 221-681), and 0 ng/mL, respectively. When the developed ELISA was further evaluated with additional samples of various types of thalassemia, including: 18 with deletional HbH disease (--/3.7 ); 21 of nondeletional HbH disease (HbH disease with HbCS) (--/ cs ); 33 with 0 thalassemia (--/ ); 19 with nondeletional + thalassemia ( / cs ); 11 with deletional + thalassemia (3.7 / ) and 58 normal subjects ( / ). It was found that the levels of Hb Bart’s in deletional + thalassemia was significantly lower than in 0 thalassemia (p<0.001). The levels of Hb Bart’s in 0 thalassemia was also significantly lower than in nondeletional and deletional HbH diseases (p=0.023 and p<0.001, respectively). When all types of thalassemia were compared with normal subjects, the Hb Bart’s levels in all types of thalassemia were significantly higher (p<0.0001). All of our results indicated that the developed ELISA was highly sensitive and specific for quantitative determination of Hb Bart’s in hemolysates. The ELISA assay might be used as a rapid screening test for the detection of thalassemias in general population.