Proteomics and in silico approaches to extend understanding of the glutathione transferase superfamily of the tropical liver fluke Fasciola gigantica.

Fasciolosis is an important foodborne, zoonotic disease of livestock and humans, with global annual health and economic losses estimated at several billion US$. Fasciola hepatica is the major species in temperate regions, while F. gigantica dominates in the tropics. In the absence of commercially available vaccines to control fasciolosis, increasing reports of resistance to current chemotherapeutic strategies and the spread of fasciolosis into new areas, new functional genomics approaches are being used to identify potential new drug targets and vaccine candidates. The glutathione transferase (GST) superfamily is both a candidate drug and vaccine target. This study reports the identification of a putatively novel Sigma class GST, present in a water-soluble cytosol extract from the tropical liver fluke F. gigantica. The GST was cloned and expressed as an enzymically active recombinant protein. This GST shares a greater identity with the human schistosomiasis GST vaccine currently at Phase II clinical trials than previously discovered F. gigantica GSTs, stimulating interest in its immuno-protective properties. In addition, in silico analysis of the GST superfamily of both F. gigantica and F. hepatica has revealed an additional Mu class GST, Omega class GSTs, and for the first time, a Zeta class member.

Influence of antiestrogens on the migration of breast cancer cells using an in vitro wound model.

The metastasis of malignant tumor cells to other organs in the body is the major cause of cancer-related patient mortality. Therefore, the inhibition of tumor cell motility is critical in the prevention or control of tumor malignancy. In the present study, the antimetastatic potential of antiestrogens [tamoxifen (TAM); ICI-182,780 (ICI); and Analog II (AII)] on highly invasive, estrogen receptor (ER)-negative MDA-MB-231 (MDA) and non-invasive, ER-positive MCF-7 (MCF) human breast cancer cell lines was investigated using an in vitro wound model. Wounds were created in confluent cell cultures and repopulation of the wound space was evaluated by counting the number of cells that migrated into the wound area and by measuring the maximum distance traveled. In addition, the number of cells that were passively seeded into the wounded area was determined. ICI and AII reduced the number of MCF cells that migrated into the wounded area and reduced the number of viable passively seeded MDA cells. Unlike ICI and AII, TAM appeared to enhance MCF and MDA cell movement. This study indicates that the in vitro wound technique is applicable to the study of breast cancer cell movement in response to antiestrogens and other antimetastatic agents. It also demonstrates that antiestrogens differ in their influence on breast cancer cell migration.

Differential influence of antiestrogens on the in vitro release of gelatinases (type IV collagenases) by invasive and non-invasive breast cancer cells.

Matrix metalloproteinases (MMPs) play an important role in tumor cell invasion and cancer metastasis. Accordingly, a higher level of these enzymes has been associated with the invasive phenotype. In the present study the effect of the antiestrogens, Analog II (AII), ICI-182,780 (ICI), and tamoxifen (TAM), on the in vitro release of MMPs, particularly gelatinases A and B by the MDA-MB-231 (MDA) and MCF-7 (MCF) human breast cancer cell lines was investigated using a solid-phase radioassay and substrate gel zymography. Quantitatively, the enzyme activity was found to be higher in the incubation medium from estrogen receptor (ER)-negative and more metastatic MDA cells compared to ER-positive and less metastatic MCF cells. Tissue inhibitor of metalloproteinases-1 (TIMP-1) reduced the enzyme activity in media from both MDA (56.36%) and MCF (71.03%) cells. Differential antiestrogen effects on the two cell lines were observed following 4 days of treatment of cells at a concentration of 10(-6)M. The enzyme activity from MDA cells was not influenced by treatment with any of the antiestrogens, whereas, in MCF cells, ICI produced the greatest enzyme inhibition (47.93%), followed by AII (36.51%) and TAM (24.05%). Concurrent treatment of MCF cells with 17-beta-estradiol (10(-9)M) partially reversed the AII- and TAM-induced but did not alter ICI-induced inhibition of enzyme activity. Substrate gel zymography revealed that among the MMPs, the MDA cells released predominantly progelatinase A (72 kDa) along with minor bands of activated forms, 62 kDa and 59 kDa, whereas progelatinase B (92 kDa) was detected predominantly in the medium from MCF cells. Comparison of the overall antiestrogen effect indicates that ICI is the most potent inhibitor of enzyme activity in ER-positive MCF cells and that antiestrogen treatment may limit the metastatic potential of ER-positive breast cancer.