Aquaretic inhibits renal cancer proliferation: Role of vasopressin receptor-2 (V2-R).

Vasopressin (AVP) is a hormone with antidiuretic properties that is also involved in cellular proliferation of breast, pulmonary, and pancreatic neoplasias, attributable to the interaction with specific receptors, among which is the V2-R. Using a culture model of CAKI-2 and A498 cancer cells, our study aimed to verify if renal carcinoma cells also express V2-R and whether receptor activation modulates their proliferation. Immunofluorescence and RT-PCR showed that both CAKI-2 and A498 cells effectively synthesize and express the V2-R. Administration of the vasopressin analogue DDAVP induced an evident growth in both CAKI-2 and A498 cell lines. However, this proliferative effect was completely avoided by the preventive addition of the V2-R antagonist SR121463B (satavaptan). Our study shows for the first time that renal cancer may effectively synthesize and express the V2-R. Furthermore, AVP exerts in vitro a proliferative effect by acting on this receptor, as the selective V2-R blockage is able to completely prevent the cellular growth. A validation of these findings with in vivo models is required to ascertain if the eventual presence of V2-R could influence the aggressiveness of human renal neoplasias. From this point of view, a new, interesting therapeutical application of V2-R antagonists in the treatment of renal cancer could also be proposed, similar to that successfully described in the treatment of autosomal polycystic kidney disease (ADPKD).

The intracellular effects of non-ionic amphiphilic cyclodextrin nanoparticles in the delivery of anticancer drugs.

The aim of this study was to develop nanoparticles made of the amphiphilic cyclodextrin heptakis (2-O-oligo(ethyleneoxide)-6-hexadecylthio-)-beta-CD (SC16OH) entrapping docetaxel (Doc) and establish their in vivo potential. Doc-loaded SC16OH nanoparticles were prepared by the emulsion-solvent evaporation technique and fully characterized for size, zeta potential, amount of entrapped drug, release rate and degradation rate. Spherical vesicular nanoparticles displaying a hydrodynamic radius of about 95 nm which did not change upon storage as an aqueous dispersion, a negative zeta potential and entrapment efficiency of Doc very close to 100% were produced. DSC study highlighted the crystalline nature of SC16OH, unloaded and Doc-loaded SC16OH nanoparticles which resulted in their very slow dissolution during release stage and well-modulated release of entrapped Doc for about 8 weeks. Doc-loaded SC16OH nanoparticles were not hemolytic toward red blood cells as compared to a commercial Doc formulation (Taxotere) which shows a dose-dependent toxicity. After exposure of HEp-2 cells to equivalent doses of free Doc and Doc-loaded SC16OH nanoparticles, superior cell killing and cell damage were observed for nanoparticles. Finally, cell damage was attributed to aberrant mitosis which was found to be significantly higher for HEp-2 cells treated with Doc-loaded SC16OH nanoparticles as compared to free Doc likely due to the ability of nanoparticles to slowly release the drug allowing prolonged cell arrest in mitosis. Taken together, these results highlights a great potential of nanoparticles based on SC16OH in solid tumors therapy.

Involvement of gD/HVEM interaction in NF-kB-dependent inhibition of apoptosis by HSV-1 gD.

In the present paper, we aimed to verify whether the interaction of the glycoprotein D (gD) of herpes simplex 1 (HSV-1) with the HSV-1 receptor HVEM is involved in NF-kappaB-dependent protection against apoptosis by gD. To this purpose, first we utilized MAbs that interfere with gD/HVEM interaction and U937 cells that naturally express human HVEM on their surface. Pre-incubation with these MAbs, but not with a control antibody, partially reverted the protection of infectious HSV-1 towards anti-Fas induced apoptosis in U937 cells. Similarly, pre-incubation of UV-inactivated HSV-1 (UV-HSV-1) or recombinant gD with the same MAbs, significantly reduced the inhibition of Fas-mediated apoptosis by UV-HSV-1 or gD, respectively, in U937 cells. Moreover, coculture with stable transfectants expressing at surface level wild type gD protected U937 cells against Fas-induced apoptosis, while coculture with transfectants expressing a mutated form of gD, incapable to bind HVEM, did not protect. Finally, UV-HSV-1 protected against staurosporine-induced apoptosis in U937 cells as well as in the CHO transfectants expressing human HVEM on their surface, but not in the control CHO transfectants, which did not express HVEM. These results suggest that signaling triggered by binding of gD to HVEM could represent an additional mechanism of evasion from premature apoptotic death exerted by HSV-1-gD in HVEM-expressing cells, disclosing new opportunities of cell death manipulation by using gD preparations.

Involvement of HVEM receptor in activation of nuclear factor kappaB by herpes simplex virus 1 glycoprotein D.

The UV-inactivated herpes simplex virus 1 (HSV-1) and glycoprotein D (gD) of HSV-1 have been shown to activate nuclear factor kappaB (NF-kappaB) in U937 cells, but mechanisms involved in this activation have not been elucidated. Here we report that: (i) UV-inactivated HSV-1 induced an increased NF-kappaB activation in cells expressing human HVEM (for herpesvirus entry mediator) at surface level, naturally or following stable transfection, but not in cells in which this receptor was not detected by flow cytometry analysis, (ii) treatment with soluble gD induced a dose-dependent NF-kappaB activation in THP-1 cells naturally expressing HVEM, and a monoclonal antibody that prevents binding of gD to HVEM significantly reduced NF-kappaB activation by soluble gD in the same cells, (iii) coculture with transfectants expressing wild-type gD on their surface induced an approximately twofold increase in NF-kappaB activation in cells naturally expressing HVEM, while coculture with transfectants expressing a mutated form of gD, lacking its capability to bind HVEM, did not induce a similar effect and (iv) treatment with soluble gD induced a dose-dependent NF-kappaB activation in CHO transfectants expressing HVEM, but not in control CHO transfectants lacking any functional gD receptor. Overall, these results establish that HVEM is involved in NF-kappaB activation by HSV-1 gD.

Signaling pathway used by HSV-1 to induce NF-kappaB activation: possible role of herpes virus entry receptor A.

We have previously demonstrated that wild-type herpes simplex virus type 1 (HSV-1), as well as nonreplicating UV-inactivated HSV-1, promptly activates the nuclear factor-kappaB (NF-kappaB) in U937 monocytoid cells and that glycoprotein D (gD) of HSV-1 is sufficient by itself to exert a similar effect. We then investigated the signaling pathway used by HSV-1 to initiate NF-kappaB activation and, particularly, whether our observation could be related to the capability of HSV-1-gD to directly stimulate NF-kappaB through its interaction with the herpes virus entry receptor A (HveA). Here we report that: (a) co-cultivation of U937 cells with an adherent cell line expressing wild-type gD on its surface led to increased NF-kappaB activation, while co-cultivation with the same adherent cell line expressing a mutated form of gD, lacking the capability to bind HveA, did not cause the same effect; (b) exposure to UV-inactivated HSV-1 induced the activation of NF-kappaB in HveA-expressing U937 and THP-1 cells, but not in non-HveA-expressing HEp-2 cells; and (c) activation of NF-kappaB in U937 and THP-1 cells exposed to soluble gD was inhibited by an antibody able to interfere with gD-HveA interaction. These results suggest that HSV-1-gD-HveA interaction initiates a signal transduction pathway leading to NF-kappaB activation.