Metastasis of cancer cells is a complex process involving multiple steps including invasion, angiogenesis, and trafficking of cancer cells through blood vessels, extravasations, organ-specific homing, and growth. While matrix metalloproteinases, urokinase-type plasminogen activator, and cytokines play a major role in invasion and angiogenesis, chemokines such as stromal derived factor-1␣ (SDF-1␣) and their receptors such as CXCR4 are thought to play a critical role in motility, homing, and proliferation of cancer cells at specific metastatic sites. We and others have previously reported that the extracellular signal-activated transcription factor NF-B up-regulates the expression of matrix metalloproteinases, urokinase-type plasminogen activator, and cytokines in highly metastatic breast cancer cell lines. In this report, we demonstrate that NF-B regulates the motility of breast cancer cells by directly up-regulating the expression of CXCR4. Overexpression of the inhibitor of B (IB) in breast cancer cells with constitutive NF-B activity resulted in reduced expression of CXCR4 and a corresponding loss of SDF-1␣-mediated migration in vitro. Introduction of CXCR4 cDNA into IB-expressing cells restored SDF-1␣-mediated migration. Electrophoretic mobility shift assays and transient transfection assays revealed that the NF-B subunits p65 and p50 bind directly to sequences within the ؊66 to ؉7 region of the CXCR4 promoter and activate transcription. We also show that the cell surface expression of CXCR4 and the SDF-1␣-mediated migration are enhanced in breast cancer cells isolated from mammary fat pad xenografts compared with parental cells grown in culture. A further increase in CXCR4 cell surface expression and SDF-1␣-mediated migration was observed with cancer cells that metastasized to the lungs. Taken together, these results implicate NF-B in the migration and the organ-specific homing of metastatic breast cancer cells.Morbidity and mortality in cancer are mainly due to organspecific metastasis and the failure of chemotherapeutic drugs to selectively kill cancer cells at the sites of metastasis. Metastasis is a non-random process, and each cancer type has its own preferred sites of metastasis (1). For example, breast cancer cells preferentially metastasize to the regional lymph nodes, lungs, liver, and bone (1, 2). Prostate cancers usually metastasize to bone. While there has been considerable progress in identifying genes that promote the metastasis of cancer cells, little is known about the genes that enable cancer cells to seed, survive, and proliferate at sites of metastasis. Three models of organ-specific metastasis are currently under consideration: 1) selective survival and proliferation of cancer cells in a particular organ due to local production of appropriate growth factors, 2) organ-specific endothelial cells trapping circulating tumor cells by expressing appropriate adhesion molecules on their surface, and 3) organ-specific attractant molecules helping in homing cancer cells to specific sites (3). While...

Beta-transducin repeats-containing proteins (b-TrCP) serve as the substrate recognition subunits for the SCF b-TrCP E3 ubiquitin ligases. These ligases ubiquitinate specifically phosphorylated substrates and play a pivotal role in the regulation of cell division and various signal transduction pathways, which, in turn, are essential for many aspects of tumorigenesis. We review the functions of the SCF b-TrCP ligases in the light of their relevance to cell growth, survival and transformation. Mechanisms underlying b-TrCP regulation and their aberration in human and animal cancer as well as prospective of targeting bTrCP as a means of anticancer therapy are also discussed.

The deubiquitylating enzyme USP7 (HAUSP) sits at a critical node regulating the activities of numerous proteins broadly characterized as tumor suppressors, DNA repair proteins, immune responders, viral proteins, and epigenetic modulators. Aberrant USP7 activity may promote oncogenesis and viral disease making it a compelling target for therapeutic intervention. Disclosed drug discovery programs have identified inhibitors of USP7 such as P005091 with cellular proof of concept and anti-proliferative activity in cancer models. Taken together, USP7 inhibitors hold promise as a new strategy for the treatment of disease.

In vitro propagation followed by PCR, and a PCR-based method capable of the direct detection of Blastocystis in faeces were utilized to detect Blastocystis from various hosts in Australia, including primates and their handlers from the Perth Zoo. In addition, Blastocystis isolates from dogs and humans living in a localized endemic community in Thailand were also characterized genetically. PCR-based detection directly from faeces was shown to be more sensitive compared with in vitro culture for the detection of Blastocystis. Moreover, phylogenetic analysis of Blastocystis isolates amplified utilizing in vitro techniques prior to PCR revealed that this method favoured the preferential amplification of Blastocystis subtype 5 over subtype 1. This study is the first to provide molecular-based evidence supporting the zoonotic potential of Blastocystis in dogs, possums and primates in a natural setting.

Inhibitors of the cancer-related cysteine isopeptidase human ubiquitin-specific proteases 7 (USP7) and 47 (USP47) are considered to have potential as cancer therapeutics, owing to their ability to stabilize the tumor suppressor p53 and to decrease DNA polymerase β (Polβ), both of which are potential anticancer effects. A new class of dual small molecule inhibitors of these enzymes has been discovered. Compound 1, a selective inhibitor of USP7 and USP47 with moderate potency, demonstrates inhibition of USP7 in cells and induces elevated p53 and apoptosis in cancer cell lines. Compound 1 has been shown to demonstrate modest activity in human xenograft multiple myeloma and B-cell leukemia in vivo models. This activity may be the result of dual inhibition of USP7 and USP47. To address issues regarding potency and developability, analogues of compound 1 have been synthesized and tested, leading to improvements in potency, solubility, and metabolic reactivity profile. Further optimization is expected to yield preclinical candidates and, ultimately, clinical candidates for the treatment of multiple myeloma, prostate cancer, and other cancers.