Synthesis and Aldose Reductase Inhibitory Activity of Botryllazine A Derivatives.

Aldose reductase (AR) is associated with the onset of diabetic complications. Botryllazine A and its analogues were synthesized and evaluated for human AR inhibitory activity. Analogues possessing aromatic bicyclic systems at the C5 position of the central pyrazine ring exhibited superior AR inhibiting activity relative to the parent botryllazine A. In addition, the benzoyl groups at positions C2 and C3 of the pyrazine ring were dispensable for this improved inhibitory activity. Conversely, a benzoyl group-containing phenolic hydroxyl groups-at either position C2 or C3 of the pyrazine ring was essential for attainment of high inhibitory activity approaching that of sorbinil (a highly effective AR inhibitor).

Regulation of ß-Catenin Phosphorylation by PR55ß in Adenoid Cystic Carcinoma.

BACKGROUND/AIM: Adenoid cystic carcinoma (AdCC) is a rare cancer of the salivary gland with high risk of recurrence and metastasis. Wnt signalling is critical for determining tumor grade in AdCC, as it regulates invasion and migration. ß-catenin dephosphorylation plays an important role in the Wnt pathway, but its underlying molecular mechanism remains unclear. MATERIALS AND METHODS: Because the regulatory subunits of protein phosphatase 2A (PP2A) drive Wnt signalling via target molecules, including ß-catenin, we used qRT-PCR and immunoblot analysis to investigate the expression of these subunits in an AdCC cell line (ACCS) and a more aggressive subline (ACCS-M). RESULTS: PR55ß was highly expressed in ACCS-M, suggesting its functional importance. In addition, PR55ß expression was associated with tumor grade, with ACCS-M exhibiting higher PR55ß levels. More importantly, knockdown of PR55ß in ACCS-M cells significantly reduced invasiveness and metastatic ability. Furthermore, dephosphorylation and total levels of ß-catenin were dependent on PR55ß in ACCS-M. Finally, we confirmed a correlation between PR55ß staining intensity and histopathological type in human AdCC tissues. CONCLUSION: Our study provides new insight into the interaction between PR55ß and ß-catenin and suggests that PR55ß may be a target for the clinical treatment of AdCC.

Deregulation of Nicotinamide N-Methyltransferase and Gap Junction Protein Alpha-1 Causes Metastasis in Adenoid Cystic Carcinoma.

BACKGROUND/AIM: Adenoid cystic carcinoma (AdCC) is a malignant tumor that occurs in the salivary glands and frequently metastasizes. The aim of this study was to identify factors mediating AdCC metastasis. MATERIALS AND METHODS: We established three AdCC cell lines by orthotropic transplantation and in vivo selection: parental, highly metastatic (ACCS-M-GFP), and lymph node metastatic (ACCS-LN-GFP) cells. RESULTS: We examined the three cell lines. DNA microarray indicated significantly altered processes in ACCS-LN-GFP cells: particularly, the expression of nicotinamide N-methyltransferase (NNMT) was enhanced the most. NNMT is associated with tumorigenesis and is a potential tumor biomarker. Concomitantly, we found-significant down-regulation of gap junction protein alpha-1. We suggest that ACCS-LN-GFP cells acquire cancer stem cell features involving the up-regulation of NNMT and the loss of gap junction protein alpha-1, leading to epithelial-mesenchymal transition and consequent AdCC metastasis. CONCLUSION: NNMT is a potential biomarker of AdCC.

Expression of erythropoietic cytokines in α-tocopherol transfer protein knockout mice with murine malaria infection.

Malaria infection leads to anemia in humans which generally occurs during the chronic phase of the infection. The role that erythropoietic molecules play for anemia during malaria at low parasitemia levels is still controversial due to the lack of suitable animal models which might mimic this condition. In this regard, α-tocopherol transfer protein knockout mice, with undetectable levels of vitamin E in circulation, were possibly used as a model to investigate the role that erythropoietic molecules such as erythropoietin (EPO), erythropoietin receptor (EPOR), and macrophage migration inhibitory factor (MIF) play on the outcome of anemia during uncomplicated malaria infection at low parasitemias. The results indicate that the degree of parasitemia unlikely plays any important effect on mRNA expression of EPO and EPOR in different organs. Moreover, even though EPO and EPOR productions are impaired in the kidney and bone marrow, respectively, other organs such as the liver and spleen intend to compensate production of these cytokines to prevent anemia in the infected animals.

Alpha-tocopherol transfer protein disruption confers resistance to malarial infection in mice.

BACKGROUND: Various factors impact the severity of malaria, including the nutritional status of the host. Vitamin E, an intra and extracellular anti-oxidant, is one such nutrient whose absence was shown previously to negatively affect Plasmodium development. However, mechanisms of this Plasmodium inhibition, in addition to means by which to exploit this finding as a therapeutic strategy, remain unclear. METHODS: alpha-TTP knockout mice were infected with Plasmodium berghei NK65 or Plasmodium yoelii XL-17, parasitaemia, survival rate were monitored. In one part of the experiments mice were fed with a supplemented diet of vitamin E and then infected. In addition, parasite DNA damage was monitored by means of comet assay and 8-OHdG test. Moreover, infected mice were treated with chloroquine and parasitaemia and survival rate were monitored. RESULTS: Inhibition of alpha-tocopherol transfer protein (alpha-TTP), a determinant of vitamin E concentration in circulation, confers resistance to malarial infection as a result of oxidative damage to the parasites. Furthermore, in combination with the anti-malarial drug chloroquine results were even more dramatic. CONCLUSION: Considering that these knockout mice lack observable negative impacts typical of vitamin E deficiency, these results suggest that inhibition of alpha-TTP activity in the liver may be a useful strategy in the prevention and treatment of malaria infection. Moreover, a combined strategy of alpha-TTP inhibition and chloroquine treatment might be effective against drug resistant parasites.