Growth suppression of colorectal cancer expressing S492R EGFR by monoclonal antibody CH12 / 医学前沿

Colorectal cancer (CRC) is a common malignant tumor in the digestive tract, and 30%-85% of CRCs express epidermal growth factor receptors (EGFRs). Recently, treatments using cetuximab, also named C225, an anti-EGFR monoclonal antibody, for CRC have been demonstrated to cause an S492R mutation in EGFR. However, little is known about the biological function of S492R EGFR. Therefore, we attempted to elucidate its biological function in CRC cells and explore new treatment strategies for this mutant form. Our study indicated that EGFR and S492R EGFR accelerate the growth of CRC cells in vitro and in vivo and monoclonal antibody CH12, which specifically recognizes an EGFR tumor-specific epitope, can bind efficiently to S492R EGFR. Furthermore, mAb CH12 showed significantly stronger growth suppression activities and induced a more potent antibody-dependent cellular cytotoxicity effect on CRC cells bearing S492R EGFR than mAb C225. mAb CH12 obviously suppressed the growth of CRC xenografts with S492R EGFR mutations in vivo. Thus, mAb CH12 may be a promising therapeutic agent in treating patients with CRC bearing an S492R EGFR mutation.

Preparados homeopáticos e ambiente de cultivo na produção e rendimento de quercetina em carqueja [Baccharis trimera (Less) DC. ] / Homeopathic preparations and crop environments through production and yield of quercetin on carqueja plants [Baccharis trimera (Less) DC. ]

A carqueja (Baccharis trimera) é uma espécie da família Asteraceae muito utilizada na medicina popular por apresentar várias atividades biológicas relacionadas à seus metabólitos secundários, entre eles os flavonoides. Este experimento teve como objetivo avaliar os efeitos de preparados homeopáticos e do ambiente de cultivo na produção e rendimento de flavonoides totais expressos em quercetina por plantas de carqueja. Foi adotado o esquema fatorial 6 x 2 no delineamento inteiramente casualisado, sendo 5 tratamentos homeopáticos: Silicea CH6, CH12, CH30, D7 e Equisetum D7 e controle (etanol 70%) x 2 ambientes de cultivo: estufa e tela de sombreamento 50%, com 4 repetições, totalizando 48 unidades experimentais. Os tratamentos homeopáticos foram aplicados na concentração de 25 gotas/500 mL de água destilada usando borrifadores manuais. Cada planta recebeu 10 mL da solução por aplicação, via foliar. As aplicações foram realizadas sempre pela manha, três vezes por semana, em dias alternados, durante dois meses (27/07/2010 a 27/09/2010). A interação entre os fatores, assim como os fatores independentes foram comparados pelo teste Tukey a 5% de probabilidade. O efeito dos preparados homeopáticos e dos dois ambientes de cultivo em plantas de carqueja foi avaliado pelas variáveis: massa fresca (MFPA), massa seca (MSPA) e teor de quercetina (QCT) na parte aérea das plantas. As variáveis MFPA e QCT foram influenciadas pelos ambientes de cultivo, pelos preparados homeopáticos e pela interação entre os dois fatores. A variável MSPA foi influenciada apenas pela interação dos fatores. Plantas cultivadas em ambiente com 50% de sombreamento associadas à aplicação dos preparados homeopáti-cos Silicea CH6 e D7, apresentaram maior rendimento em querceti-na. Plantas cultivadas na estufa associadas à aplicação do Equisetum D7 apresentaram menor rendimento em quercetina.

The carqueja plant (Baccharis trimera) is a specie of the family Asteraceae widely used in folk medicine for presenting various biological activities, due to the high content of secondary metabolites, including flavonoids. The objective of this study was to evaluate the effect of homeopathic preparations and crop environments through production and yield of quercetina on carqueja plants. The experiment was a factorial scheme (6X2) on completely randomized design with 5 homeopathic treatments: Silicea CH6, CH12, CH30, D7 and Equisetum D7 e control (70% ethanol) x 2 crop environments: greenhouse and shade 50% and 4 replicates, totaling 48 experimental units. The treatments were applied at concentration of 25 drops/500 mL of distilled water using hand sprayers. Each plant received 10 mL via leaves. The prepara-tions were sprayed always on mornings, three times a week on alternate days during two months (27/09/2010 to 27/11/2010). The interaction between the factors as well as the independents factors were compared by the Tukey test at 5% probability. The effect of homeopathic preparations and the two crop environments on carqueja plants were evaluated through the variables: fresh matter of aerial part (FMAP), dry matter of aerial part (DMAP) and flavonoids content (QCT). The variables FMAP and QCT were significantly influenced by the crop environments, the preparations and interaction between the two factors. The DMAP was only influenced by the interaction of the two factors. The 50% shade environment associated with Silicea CH6 or D7 increased yield of quercetin. The greenhouse environment associated with Equisetum D7 decreased yield of quercetin.

Characterization of Mouse B Lymphoma Cells (CH12F3-2A) for the Study of IgA Isotype Switching

BACKGROUND: It is well known that IgA isotype switching is induced by TGF-beta1. LPS-activated mouse normal B cells well differentiate into IgA secreting plasma cells under the influence of TGF-beta1. Nevertheless, there are lots of difficulties in studying normal B cells in detail because it is not simple to obtain highly purified B cells, showing low reproducibility and transfection efficacy, moreover impossible to keep continuous culture. To overcome these obstacles, it is desperately needed to develop B cell line which acts like normal B cells. In the present study, we investigated whether CH12F3-2A lymphoma cells are appropriate for studying IgA isotype switching event. METHODS: CH12F3-2A B cell line was treated with LPS and TGF-beta1, then levels of germ-line (GL) transcripts were measured by RT-PCR, and GLalpha promoter activity was measured by luciferase assay. In addition, membrane IgA (mIgA) expression and IgA secretion were determined by FACS and ELISA, respectively. RESULTS: TGF-beta1, regardless of the presence of LPS, increased level of GLalpha transcripts but not GLgamma2b transcripts. However, IgA secretion was increased dramatically by co-stimulation of LPS and TGF-beta1. Both mIgA and IgA secretion in the presence of TGF-beta1 were further increased by over-expression of Smad3/4. Finally, GLalpha promoter activity was increased by TGF-beta1. CONCLUSION: CH12F3-2A cell line acts quite similarly to the normal B cells which have been previously reported regarding IgA expression. Thus, CH12F3-2A lymphoma cell line appears to be adequate for the investigation of the mechanism(s) of IgA isotype switching at the cellular and molecular levels.