Project description:P. falciparum is the deadliest causative agent of human malaria. This parasite has historically developed resistance to many drugs, including the current frontline treatments, so new therapeutic targets are needed Our previous work on guanine quadruplexes (G4s) in the parasite’s DNA and RNA has highlighted their influence on parasite biology, and also revealed G4 stabilising compounds as promising candidates for drug repositioning. In particular, quarfloxin, a former anticancer agent, kills blood-stage parasites at all developmental stages, with fast rates of kill and nanomolar potency. Here we explored the molecular mechanism of quarfloxin and its related derivative CX-5461. In vitro, both compounds bound to P. falciparum-encoded G4 sequences. In cellulo, quarfloxin was more potent than CX-5461, and could prevent establishment of blood-stage malaria in vivo in a murine model. CX-5461 showed clear DNA damaging activity, as reported in human cells, while quarfloxin caused weaker signatures of DNA damage. Both compounds caused transcriptional dysregulation in the parasite, but the affected genes were largely different, again suggesting different modes of action. Therefore, CX-5461 may act primarily as a DNA damaging agent in both Plasmodium parasites and mammalian cells, whereas the complete anti-malarial mode of action of quarfloxin may be parasite-specific, and remains elusive.
Project description:Platinum-based compounds exert their anti-neoplastic effect through direct binding to DNA, which blocks fundamental cellular process ultimately resulting in apoptotic cell death. However, many ovarian cancers become refractory to treatment with platinum-based compounds. To improve the existing therapies for ovarian cancer, we sought to identify potent, nontoxic and specific drug candidates that have anti-neoplastic effects towards cisplatin-sensitive and cisplatin-resistant ovarian cancer cells. Using a cell-based screening assay, we evaluated 56 compounds-derived from the Chinese medicinal plant, Phytolaccae, and one phytoaccagenin compound (Hu-17) was selected on the basis of its ability to dramatically decrease the viability of cisplatin-resistant SK-OV-3 cells.Using high-throughtput microarray system, we identified GO terms and pathway signatures enriched in Hu-17 and/or cisplatin treated SK-OV-3 cells.
Project description:We introduce a family of multivalent peptidomimetic conjugates that modulate the activity of the androgen receptor (AR). Bioactive ethisterone ligands were conjugated to a set of sequence-specific peptoid oligomers. Certain multivalent peptoid conjugates enhance AR-mediated transcriptional activation. We identify a linear and a cyclic conjugate that exhibit potent anti-proliferative activity in LNCaP-abl cells, a model of therapy-resistant prostate cancer. The linear conjugate blocks AR action by competing for ligand binding. In contrast, the cyclic conjugate is active despite its inability to compete against endogenous ligand for binding to AR in vitro, suggesting a non-competitive mode of action. These results establish a versatile platform to design competitive and non-competitive AR modulators with potential therapeutic significance. We use microarray analysis to further elucidate the mechanism of AR antagonism and show that the compounds (cyc and n=8) are distinct. We used microarray analysis to see genone-wide effects on LNCaP-abl cells with moduators of AR activity LNCaP-abl cells were treated with compound and RNA was extracted and hybridized on Affymetrix microarrays Treatments: Vehicle is just Ethanol treated LNCaP-abl cells that were used as a control. n=8 and cyc are peptoid conjugates that modulate AR activity. n=8 is linear and cyc is a cyclic compounds. We wanted to look at gene expression when LNCaP-abl cells were treated with these compounds to show that they are distinct. C3 is a small molecule that inhibits the interaction between AR and beta-catenin (co-regulator protein). Initial results with this compound show potent anti-proliferative activity in LNCaP-abl cells and we wanted to further investigate the mechanism of action of this compound.
Project description:Malaria continues to pose a significant public health threat, with millions of cases and hundreds of thousands of deaths reported annually, primarily in sub-Saharan Africa. The disease disproportionally affects children under five years of age residing in holoendemic Plasmodium falciparum transmission regions, who account for 94% of the cases and 80% of the mortality. Young children are highly vulnerable to developing life-threatening severe malarial anemia [SMA, hemoglobin (Hb)<5.0 g/dL]. The overall goal of the project was to identify critical gene pathways within the transcriptome that mediate disease severity and then target these specific genes with compounds that elicit expression profiles witnessed in children with milder forms of disease. To achieve this goal, we are investing the following specific aims: 1) Determine how changing temporal dynamics of gene pathways in the Malarial Immunity Transcriptome promote SMA during acute disease; 2) Determine how changes in gene pathways in the Malarial Immunity Transcriptome mediate malarial severity throughout the development of naturally acquired immunity; and 3) Identify immunotherapeutic targets in the Malarial Immunity Transcriptome that can be used to reduce malaria disease severity and improve clinical outcomes in future trials. To successfully complete these aims, we are determining how host profiles impact on acute disease over 14 days. We will utilize Ex vivo samples from the cohort to test the effect of immunotherapeutic compounds on host expression profiles. Accomplishing these goals will have broad reaching translational implications for: (1) identifying at-risk groups, and (2) prioritizing compounds that can be used to improve clinical outcomes in future immunotherapy trials.
Project description:Cerebral Malaria (HCM) is a serious neurological complication caused by Plasmodium falciparum infection. Currently the only treatment for HCM is the provision of anti-malarial drugs; however, such treatment by itself often fails to prevent death or development of neurological sequelae. To identify new potential adjunct treatments for HCM, we performed a non-biased whole brain transcriptomic time-course analysis of anti-malarial drug chemotherapy of murine experimental CM (ECM).
Project description:In a phenotypic screening approach of novel molecules composed of a synergistic combination of phthalimide, benzimidazole, and triazole scaffolds we discovered compounds with potent anti-leishmanial activity. The resulting early-lead compound PHT-39, which contains a trifluoromethyl substitution, demonstrated the highest efficacy in a Leishmania infantum intramacrophage assay, with an EC50 of 1.2+/- 3.2 μM.Cytotoxicity testing of PHT-39 in Hep-G2 cells indicated high selectivity of over 90-fold. To investigate the mechanism of action we carried out experiments in Trypanosoma brucei, which is also sensitive to PHT-39. Here we used a genome-wide RNAi library approach (PMID: 22278056; PMID: 21363968) to detect sensitivity determinants. This high-throughput phenotyping approach identified sensitivity determinants for PHT-39, which included a P-type ATPase that is crucial for the uptake of miltefosine and amphotericin, strongly indicating a shared route for cellular entry.
Project description:Most malaria drug development focuses on parasite stages detected in red-blood cells even though to achieve eradication next-generation drugs active against both erythrocytic and exo-erythrocytic forms would be preferable. We applied a multifactorial approach to a set of >4,000 commercially available compounds with previously demonstrated blood stage activity (IC50 < 1 µM), and identified chemical scaffolds with potent activity against both forms. From this screen, we identified an imidazolopiperazine scaffold series that was highly enriched among compounds active against Plasmodium liver stages. Our orally bioavailable lead imidazolopiperazine confers complete causal prophylactic protection (15 mg/kg) in rodent models of malaria and shows potent in vivo blood-stage therapeutic activity. The open source chemical tools resulting from our effort provide starting points for future drug discovery programs, as well as opportunities for researchers to investigate the biology of exo-erythrocytic forms.
Project description:Most malaria drug development focuses on parasite stages detected in red-blood cells even though to achieve eradication next-generation drugs active against both erythrocytic and exo-erythrocytic forms would be preferable. We applied a multifactorial approach to a set of >4,000 commercially available compounds with previously demonstrated blood stage activity (IC50 < 1 M-BM-5M), and identified chemical scaffolds with potent activity against both forms. From this screen, we identified an imidazolopiperazine scaffold series that was highly enriched among compounds active against Plasmodium liver stages. Our orally bioavailable lead imidazolopiperazine confers complete causal prophylactic protection (15 mg/kg) in rodent models of malaria and shows potent in vivo blood-stage therapeutic activity. The open source chemical tools resulting from our effort provide starting points for future drug discovery programs, as well as opportunities for researchers to investigate the biology of exo-erythrocytic forms. Genome DNA from IP resistant strains vs. Reference 3D7 or Dd2