fThe drug target profile proposed by the Medicines for Malaria Venture for a malaria elimination/eradication policy focuses on molecules active on both asexual and sexual stages of Plasmodium, thus with both curative and transmission-blocking activities. The aim of the present work was to investigate whether the class of monovalent ionophores, which includes drugs used in veterinary medicine and that were recently proposed as human anticancer agents, meets these requirements. The activity of salinomycin, monensin, and nigericin on Plasmodium falciparum asexual and sexual erythrocytic stages and on the development of the Plasmodium berghei and P. falciparum mosquito stages is reported here. Gametocytogenesis of the P. falciparum strain 3D7 was induced in vitro, and gametocytes at stage II and III or stage IV and V of development were treated for different lengths of time with the ionophores and their viability measured with the parasite lactate dehydrogenase (pLDH) assay. The monovalent ionophores efficiently killed both asexual parasites and gametocytes with a nanomolar 50% inhibitory concentration (IC 50 ). Salinomycin showed a fast speed of kill compared to that of standard drugs, and the potency was higher on stage IV and V than on stage II and III gametocytes. The ionophores inhibited ookinete development and subsequent oocyst formation in the mosquito midgut, confirming their transmission-blocking activity. Potential toxicity due to hemolysis was excluded, since only infected and not normal erythrocytes were damaged by ionophores. Our data strongly support the downstream exploration of monovalent ionophores for repositioning as new antimalarial and transmission-blocking leads.

BackgroundMedicinal plants are a validated source for discovery of new leads and standardized herbal medicines. The aim of this study was to assess the activity of Vernoniaamygdalina leaf extracts and isolated compounds against gametocytes and sporogonic stages of Plasmodiumberghei and to validate the findings on field isolates of Plasmodium falciparum.MethodsAqueous (Ver-H2O) and ethanolic (Ver-EtOH) leaf extracts were tested in vivo for activity against sexual and asexual blood stage P. berghei parasites. In vivo transmission blocking effects of Ver-EtOH and Ver-H2O were estimated by assessing P. berghei oocyst prevalence and density in Anopheles stephensi mosquitoes. Activity targeting early sporogonic stages (ESS), namely gametes, zygotes and ookinetes was assessed in vitro using P. berghei CTRPp.GFP strain. Bioassay guided fractionation was performed to characterize V.amygdalina fractions and molecules for anti-ESS activity. Fractions active against ESS of the murine parasite were tested for ex vivo transmission blocking activity on P.falciparum field isolates. Cytotoxic effects of extracts and isolated compounds vernolide and vernodalol were evaluated on the human cell lines HCT116 and EA.hy926.ResultsVer-H2O reduced the P. berghei macrogametocyte density in mice by about 50% and Ver-EtOH reduced P. berghei oocyst prevalence and density by 27 and 90%, respectively, in An.stephensi mosquitoes. Ver-EtOH inhibited almost completely (>90%) ESS development in vitro at 50 μg/mL. At this concentration, four fractions obtained from the ethylacetate phase of the methanol extract displayed inhibitory activity >90% against ESS. Three tested fractions were also found active against field isolates of the human parasite P. falciparum, reducing oocyst prevalence in Anopheles coluzzii mosquitoes to one-half and oocyst density to one-fourth of controls. The molecules and fractions displayed considerable cytotoxicity on the two tested cell-lines.ConclusionsVernonia amygdalina leaves contain molecules affecting multiple stages of Plasmodium, evidencing its potential for drug discovery. Chemical modification of the identified hit molecules, in particular vernodalol, could generate a library of druggable sesquiterpene lactones. The development of a multistage phytomedicine designed as preventive treatment to complement existing malaria control tools appears a challenging but feasible goal.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-015-0812-2) contains supplementary material, which is available to authorized users.

Chemopreventive effects and associated mechanisms of Withaferin A (WA) against intestinal and colon carcinogenesis remain unknown. We investigated the chemopreventive effect of WA on transgenic mouse APCMin/+ and chemically induced azoxymethane/dextran sodium sulfate (AOM/DSS) models of intestinal and colon carcinogenesis. Oral WA administration (4 mg/kg and 3mg/kg) inhibited tumor initiation and progression of intestinal polyp formation in APCMin/+ mice and colon carcinogenesis in the AOM/DSS mouse model. WA-administered mice showed a significant reduction in both number (duodenum, 33% (p>0.05); jejunum, 32% (p<0.025); ileum, 43% (p<0.001); and colon 59% (p<0.01) and size of polyps in APCMin/+ mice compared to the respective controls. Similarly, tumor multiplicity was significantly reduced (p<0.05) in the colon of WA-administered AOM/DSS mice. Pathological analysis showed reduced adenomas and tissue inflammation in WA-administered mouse models. Molecular studies suggested that WA inhibited the expression of inflammatory (IL-6, TNFα and COX2), pro-survival (pAKT, Notch1, and NF-κB), markers in APCMin/+ and AOM/DSS models. The results suggest that WA is a potent agent for preventing colon carcinogenesis and further investigation is required to show clinical utility of the agent.

Androgen ablation therapy is the primary therapeutic option for locally advanced and metastatic castration-resistant prostate cancer (CRPC). We investigated therapeutic effect of a dietary metabolite Urolithin A (UroA) and dissected the molecular mechanism in CRPC cells. Treatment with UroA inhibited cell proliferation in both androgen receptor-positive (AR ) (C4-2B) and androgen receptor-negative (AR ) (PC-3) cells however, AR CaP cells were more sensitive to UroA treatment as compared with AR CaP cells. Inhibition of the AR signaling was responsible for the UroA effect on AR CaP cells. Ectopic expression of AR in PC-3 cells sensitized them to UroA treatment as compared to the vector-expresseing PC-3 cells, which suggests that AR could be a target of UroA. Similarly, in enzalutamide-resistant C4-2B cells, a downregulation of AR expression also suppressed cell proliferation which was observed with the UroA treatment. Oral administration of UroA significantly suppressed the growth of C4-2B xenografts (P = 0.05) compared with PC-3 xenografts (P = 0.069) without causing toxicity to animals. Immunohistochemistry analysis confirmed in vitro findings such as downregulation of AR/pAKT signaling in UroA-treated C4-2B tumors, which suggests that UroA may be a potent chemo-preventive and therapeutic agent for CRPC.

Epidemiological evidence suggests that cadmium (Cd) is one of the causative factors of prostate cancer, but the effect of Cd on benign prostatic hyperplasia (BPH) remains unclear. This study aimed to determine whether Cd exposure could malignantly transform BPH1 cells and, if so, to dissect the mechanism of action. We deciphered the molecular signaling responsible for BPH1 transformation via RNA-sequencing and determined that Cd induced the expression of zinc finger of the cerebellum 2 (ZIC2) in BPH1 cells. We noted Cd exposure increased ZIC2 expression in the Cdtransformed BPH1 cells that in turn promoted anchorage-independent spheroids and increased expression of stem cell drivers, indicating their role in stem cell renewal. Subsequent silencing of ZIC2 expression in transformed cells inhibited spheroid formation, stem cell marker expression, and tumor growth in nude mice. At the molecular level, ZIC2 interacts with the glioma-associated oncogene family (GLI) zinc finger 1 (GLI1), which activates prosurvival factors (nuclear factor NFκB, B-cell lymphoma-2 (Bcl2), as well as an X-linked inhibitor of apoptosis protein (XIAP)) signaling in Cd-exposed BPH1 cells. Conversely, overexpression of ZIC2 in BPH1 cells caused spheroid formation confirming the oncogenic function of ZIC2. ZIC2 activation and GLI1 signaling induction by Cd exposure in primary BPH cells confirmed the clinical significance of this oncogenic function. Finally, human BPH specimens had increased ZIC2 versus adjacent healthy tissues. Thus, we report direct evidence that Cd exposure induces malignant transformation of BPH via activation of ZIC2 and GLI1 signaling. Oncogenesis 1234567890():,; 1234567890():,; 1234567890():,; 1234567890():,;

The stronger activity of NA, when compared to AzaA, could not be explained by an additive or synergistic effect by other azadirachtins (B, D and I) present in NA. In fact, the addition of these compounds at 50µM concentration to AzaA did not evidence any decrease of the IC against early sporogonic stages to that obtained with AzaA alone. It is likely that other non-limonoid compounds present in NA may contribute to AzaA activity and enhanced pharmacodynamics against exflagellation both in vitro and in vivo.

The recent emergence of resistance, toxicity paradigm and limited efficacy of conventional antifungal drugs necessitate the identification of de novo targets in fungal metabolism. One of the most critical physiological processes during in vivo pathogenesis is maintenance of iron homeostasis. The most life threatening opportunistic human fungal pathogens like Aspergillus, Candida and Cryptococcus exploit the siderophore mediated iron uptake mechanism either for survival, virulence, propagation or resistance to oxidative stress envisaged in vivo during infection. Areas covered: In this review, we will highlight the metabolic pathways; specifically siderophore biosynthesis, uptake and utilisation, triggered in the fungal pathogens in iron starving conditions and the various putative targets viable in these pathways to be recruited as novel therapeutic antidotes either via biosynthetic enzymes catalytic site inhibitors or as drug conjugates through trojan horse approach and further role in the development of fungal specific reliable diagnostic markers. Expert opinion: Siderophores are the weapons released by a pathogen to conquer the battle for iron acquisition. Hence, the fungal siderophore biosynthetic pathways along with their uptake and utilisation mechanisms represent an ideal target for pathogen specific, host friendly therapeutic strategy which would block the proliferation of parasite without causing any harm to the mammalian host.

Fecundity, bloodmeal size, and survival are among the most important parameters in the overall fitness of mosquitoes. Impact of an intervention that affects fecundity can be assessed by directly counting the eggs laid by exposed mosquitoes, which is usually done manually. We have developed a macroinstruction, which can be used to count thousands of Anopheles stephensi Liston eggs in a few minutes, to provide an alternative and adaptable method to egg counting as a measure of fecundity. The macro was developed using a scanner and a computer running AxioVision Rel. 4.8 software, a freely accessible software compatible with Windows XP/7/Vista. Using this semiautomated method, it is possible to reduce time, avoid human error and bias, and obtain improved consistency in studies measuring mosquito fecundity.