The importance of voltage-dependent Ca2+ channels (VDCCs) in pain transmission has been noticed gradually, as several VDCC blockers have been shown to be effective in inhibiting this process. In particular, the N-type VDCC has attracted attention, because inhibitors of this channel are effective in various aspects of pain-related phenomena. To understand the genuine contribution of the N-type VDCC to the pain transmission system, we generated mice deficient in this channel by gene targeting. We report here that mice lacking N-type VDCCs show suppressed responses to a painful stimulus that induces inflammation and show markedly reduced symptoms of neuropathic pain, which is caused by nerve injury and is known to be difficult to treat by currently available therapeutic methods. This finding clearly demonstrates that the N-type VDCC is essential for development of neuropathic pain and, therefore, controlling the activity of this channel can be of great importance for the management of neuropathic pain.

Hormone antagonists can be effective tools to delineate receptor signaling pathways and their resulting downstream physiological actions. Mutation of the receptor binding domain (RBD) of human H2 relaxin (deltaH2) impaired its biological function as measured by cAMP signaling. In a competition assay, deltaH2 exhibited antagonistic activity by blocking recombinant H2 relaxin from binding to receptors on THP-1 cells. In a flow cytometry-based binding assay, deltaH2 demonstrated weak binding to 293T cells expressing the LGR7 receptor in the presence of biotinylated H2 relaxin. When human prostate cancer cell lines (PC-3 and LNCaP) were engineered to overexpress eGFP, wild-type (WT) H2, or deltaH2, and subsequently implanted into NOD/SCID mice, tumor xenografts overexpressing deltaH2 displayed smaller volumes compared to H2 and eGFP controls. Plasma osmolality readings and microvessel density and area assessment suggest that deltaH2 modulates physiological parameters in vivo. In a second murine model, intratumoral injections of lentivectors engineered to express deltaH2/eGFP led to suppressed tumor growth compared to controls. This study provides further evidence supporting a role for H2 relaxin in prostate tumor growth. More importantly, we report how mutation of the H2 relaxin RBD confers the hormone derivative with antagonistic properties, offering a novel reagent for relaxin research.

Matrix metalloproteinase-2 (MMP-2) is a stroma-derived MMP belonging to the type IV collagenase family. It is believed to mediate tumor cell behavior by degrading deposits of type IV collagen, a major component of the basement membrane. The membrane type 1-MMP (MT1-MMP) is a highly potent activator of MMP-2 and is expressed in many tumor and stromal cells. However, the roles played by stromal MMP-2 in tumor progression in vivo remain poorly understood. We established a colon epithelial cell line from an Mt1-mmp This MT1-MMP-dependent tumor growth of MT1rev cells was enhanced in Mmp-2 À/À mice as long as MMP-2 was supplied via transfection or coimplantation of MMP-2-positive fibroblasts. MT1rev cells cultured in vitro in a three-dimensional collagen gel matrix also required the MT1-MMP/MMP-2 axis for rapid proliferation. MT1rev cells deposit type IV collagen primarily at the cell-collagen interface, and these deposits seem scarce at sites of invasion and proliferation. These data suggest that cooperation between stroma-derived MMP-2 and tumor-derived MT1-MMP may play a role in tumor invasion and proliferation via remodeling of the tumor-associated basement membrane. To our knowledge, this is the first study demonstrating that MT1-MMP-dependent tumor growth in vivo requires stromal-derived MMP-2. It also suggests that MMP-2 represents a potential target for tumor therapeutics.

Thoracoscopic stand-alone appendectomy is potentially safe and may allow surgeons to achieve relatively simple, complete LAA closure. Further experience may demonstrate this technique to be a viable option for thromboembolism prevention in nonvalvular AF.