Species Used for Drug Testing Reveal Different Inhibition Susceptibility for 17beta-Hydroxysteroid Dehydrogenase Type 1

Steroid-related cancers can be treated by inhibitors of steroid metabolism. In searching for new inhibitors of human 17beta-hydroxysteroid dehydrogenase type 1 (17β-HSD 1) for the treatment of breast cancer or endometriosis, novel substances based on 15-substituted estrone were validated. We checked the specificity for different 17β-HSD types and species. Compounds were tested for specificity in vitro not only towards recombinant human 17β-HSD types 1, 2, 4, 5 and 7 but also against 17β-HSD 1 of several other species including marmoset, pig, mouse, and rat. The latter are used in the processes of pharmacophore screening. We present the quantification of inhibitor preferences between human and animal models. Profound differences in the susceptibility to inhibition of steroid conversion among all 17β-HSDs analyzed were observed. Especially, the rodent 17β-HSDs 1 were significantly less sensitive to inhibition compared to the human ortholog, while the most similar inhibition pattern to the human 17β-HSD 1 was obtained with the marmoset enzyme. Molecular docking experiments predicted estrone as the most potent inhibitor. The best performing compound in enzymatic assays was also highly ranked by docking scoring for the human enzyme. However, species-specific prediction of inhibitor performance by molecular docking was not possible. We show that experiments with good candidate compounds would out-select them in the rodent model during preclinical optimization steps. Potentially active human-relevant drugs, therefore, would no longer be further developed. Activity and efficacy screens in heterologous species systems must be evaluated with caution

Clofazimine for Treatment of Cryptosporidiosis in Human Immunodeficiency Virus Infected Adults: An Experimental Medicine, Randomized, Double-blind, Placebo-controlled Phase 2a Trial

Background: We evaluated efficacy, pharmacokinetics (PK), and safety of clofazimine (CFZ) in HIV-infected patients with cryptosporidiosis. Methods: We performed a randomized, double-blind, placebo-controlled study. Primary outcomes in Part A were reduction in Cryptosporidium shedding, safety, and PK. Primary analysis was according to protocol (ATP). Part B of the study compared CFZ PK in matched HIV-infected individuals without cryptosporidiosis. Results: Twenty Part A and 10 Part B participants completed the study ATP. Almost all Part A participants had high viral loads and low CD4 counts, consistent with failure of antiretroviral (ARV) therapy. At study entry, the Part A CFZ group had higher Cryptosporidium shedding, total stool weight, and more diarrheal episodes compared to the placebo group. Over the inpatient period, compared to those who received placebo, the CFZ group Cryptosporidium shedding increased by 2.17 log2 Cryptosporidium per gram stool (95% upper confidence limit: 3.82), total stool weight decreased by 45.3 g (p=0.37), and number of diarrheal episodes increased by 2.32 (p=0.87). The most frequent solicited adverse effects were diarrhea, abdominal pain, and malaise. Three CFZ and 1 placebo subjects died during the study. Plasma levels of CFZ in participants with cryptosporidiosis were 2-fold lower than Part B controls. Conclusion: Our findings do not support the efficacy of CFZ for the treatment of cryptosporidiosis in a severely immunocompromised HIV population. However, this trial demonstrates a pathway to assess the therapeutic potential of drugs for cryptosporidiosis treatment. Screening persons with HIV for diarrhea, and especially Cryptosporidium infection, may identify those failing ARV therapy

BCG promotes cord blood monocyte-derived dendritic cell maturation with nuclear Rel-B up-regulation and cytosolic IκB α and β degradation

Mycobacterium bovis bacillus Calmette-Guerin (BCG) is given to millions of neonates in developing countries as a vaccine against Mycobacterium tuberculosis; however, little is known about the initiation of response in neonatal dendritic cells (DCs) to BCG. To address this issue, the interaction of BCG with human cord blood monocyte-derived DCs was studied. We showed that BCG could promote cord blood monocyte-derived DC maturation by up-regulation of CD80, CD83, CD86, CD40, and MHC class II molecules and down-regulation of mannose receptor. BCG was able to induce similar levels of tumor necrosis factor-α and IL-10 but no bioactive IL-12p70 production from cord blood DCs as from adult blood DCs. Functionally BCG-treated cord blood DCs had higher ability to induce mixed lymphocyte reaction than non-BCG-treated cord blood DCs. Both non-BCG-treated and BCG-treated cord blood DCs efficiently induced a high level of IL-10, medium level of interfer-on-γ, but little IL-4 production by cord blood naïve CD4+ T cells. Heat shock protein 65, a key component of BCG, had no effect on cord blood DC maturation in terms of CD86, MHC class II, and mannose receptor up-regulation. During the BCG-induced maturation process of cord blood DCs, nuclear transcription factor Rel-B was up-regulated and cytosolic Rel-B down-regulated with cytosolic IκB α and β degradation. These results suggest that BCG can promote cord blood monocyte-derived DC maturation, and that the mechanism is through the up-regulation of nuclear Rel-B secondary to the degradation of cytosolic IκB α and β.link_to_subscribed_fulltex