A mutation in caspase-9 decreases the expression of BAFFR and ICOS in patients with immunodeficiency and lymphoproliferation.

Lymphocyte apoptosis is mainly induced by either death receptor-dependent activation of caspase-8 or mitochondria-dependent activation of caspase-9. Mutations in caspase-8 lead to autoimmunity/lymphoproliferation and immunodeficiency. This work describes a heterozygous H237P mutation in caspase-9 that can lead to similar disorders. H237P mutation was detected in two patients: Pt1 with autoimmunity/lymphoproliferation, severe hypogammaglobulinemia and Pt2 with mild hypogammaglobulinemia and Burkitt lymphoma. Their lymphocytes displayed defective caspase-9 activity and decreased apoptotic and activation responses. Transfection experiments showed that mutant caspase-9 display defective enzyme and proapoptotic activities and a dominant-negative effect on wild-type caspase-9. Ex vivo analysis of the patients' lymphocytes and in vitro transfection experiments showed that the expression of mutant caspase-9 correlated with a downregulation of BAFFR (B-cell-activating factor belonging to the TNF family (BAFF) receptor) in B cells and ICOS (inducible T-cell costimulator) in T cells. Both patients carried a second inherited heterozygous mutation missing in the relatives carrying H237P: Pt1 in the transmembrane activator and CAML interactor (TACI) gene (S144X) and Pt2 in the perforin (PRF1) gene (N252S). Both mutations have been previously associated with immunodeficiencies in homozygosis or compound heterozygosis. Taken together, these data suggest that caspase-9 mutations may predispose to immunodeficiency by cooperating with other genetic factors, possibly by downregulating the expression of BAFFR and ICOS.

Solid lipid nanoparticles of cholesteryl butyrate inhibit the proliferation of cancer cells in vitro and in vivo models.

BACKGROUND AND PURPOSE: Solid lipid nanoparticles containing cholesteryl butyrate (cholbut SLN) can be a delivery system for the anti-cancer drug butyrate. These nanoparticles inhibit adhesion of polymorphonuclear and tumour cells to endothelial cells and migration of tumour cells, suggesting that they may act as anti-inflammatory and anti-tumour agents. Here we have evaluated the effects of cholbut SLN on tumour cell growth using in vitro and in vivo models. EXPERIMENTAL APPROACH: Cholbut SLNs were incubated with cultures of four tumour cell lines, and cell growth was analysed by assessing viability, clonogenic capacity and cell cycle. Effects on intracellular signalling was assessed by Western blot analysis of Akt expression. The in vivo anti-tumour activity was measured in two models of PC-3 cell xenografts in SCID/Beige mice. KEY RESULTS: Cholbut SLN inhibited tumour cell line viability, clonogenic activity, Akt phosphorylation and cell cycle progression. In mice injected i.v. with PC3-Luc cells and treated with cholbut SLN, . in vivo optical imaging and histological analysis showed no metastases in the lungs of the treated mice. In another set of mice injected s.c. with PC-3 cells and treated with cholbut SLN when the tumour diameter reached 2 mm, analysis of the tumour dimensions showed that treatment with cholbut SLN substantially delayed tumour growth. CONCLUSION AND IMPLICATIONS: Cholbut SLN were effective in inhibiting tumour growth in vitro and in vivo. These effects may involve, in part, inhibition of Akt phosphorylation, which adds another mechanism to the activity of this multipotent drug.

Dynamic air-water exchange of polychlorinated biphenyls in the New York-New Jersey Harbor Estuary.

Simultaneous measurements of polychlorinated biphenyls (PCBs) in the air and water over Raritan Bay and New York Harbor were taken in July 1998, allowing the first determinations of air-water exchange fluxes for this heavily impacted system. Average gas-phase concentrations of sigmaPCBs were 1.0 ng m(-3) above Raritan Bay and 3.1 ng m(-3) above New York Harbor. A similar gradient was observed for dissolved water concentrations (1.6 and 3.8 ng L(-1), respectively). Shallow slopes of log K(oc) vs log K(ow) plots indicated a colloidal contribution to the dissolved concentrations, and a three-phase partitioning model was therefore applied. PCBs associated with colloids ranged from 6% to 93% for trichloro- to nonachlorobiphenyls, respectively. Air-water gas exchange fluxes of sigmaPCBs exhibited net volatilization for both Raritan Bay at +400 ng m(-2) day(-1) and New York Harbor at +2100 ng m(-2) day(-1). The correction for the colloidal interactions decreased the volatilization flux of sigmaPCBs by about 15%. Net air-water exchange fluxes of PCBs are expected to remain positive throughout the year due to the large water-air fugacity gradient and relatively constant seasonal water concentrations. The volatilization fluxes are approximately 40 times greater than atmospheric deposition of PCBs via both wet and dry particle deposition, suggesting that the estuary acts as a net source of PCBs to the atmosphere year-round.