Purpose: To estimate the maximum tolerated dose (MTD) for continuous oral administration of the g-secretase inhibitor PF-03084014, determine the recommended phase II dose (RP2D), and evaluate safety and preliminary activity in patients with advanced solid tumors.Experimental Design: This open-label, phase I study consisted of a dose-finding portion based on a 3þ3 design, followed by an expansion cohort. PF-03084014 was administered orally, twice daily (BID) for 21 continuous days. Tested doses ranged from 20 to 330 mg BID. In the expansion cohort, patients were to receive the estimated MTD or a lower dose of PF-03084014.Results: A total of 64 patients received treatment. The MTD was estimated to be 220 mg BID. The RP2D was determined to be 150 mg BID, based on the better safety profile versus the 220-mg BID dose, given comparable NOTCH-related target inhibition. The most common treatment-related adverse events were diarrhea, nausea, fatigue, hypophosphatemia, vomiting, rash, and decreased appetite, which were generally mild to moderate in severity. One patient with advanced thyroid cancer had a complete response, and five of seven response-evaluable patients with desmoid tumor achieved a partial response (71.4% objective response rate). Tumor responses were mostly durable, ranging from 1.74þ to 24þ months. PF-03084014 demonstrated a generally dose-dependent pharmacokinetic profile at doses ranging from 20 to 330 mg BID. Consistent downmodulation of NOTCHrelated HES4 gene expression was observed in peripheral blood from all evaluable patients.Conclusion: Further development of PF-03084014 for the treatment of patients with advanced solid tumors is warranted and currently under evaluation.

Unlike humans and yeast, Plasmodium falciparum, the agent of the most severe form of human malaria, utilizes host serine as a precursor for the synthesis of phosphatidylcholine via a plant-like pathway involving phosphoethanolamine methylation. The monopartite phosphoethanolamine methyltransferase, Pfpmt, plays an important role in the biosynthetic pathway of this major phospholipid by providing the precursor phosphocholine via a three-step S-adenosyl-L-methionine-dependent methylation of phosphoethanolamine. In vitro studies showed that Pfpmt has strong specificity for phosphoethanolamine. However, the in vivo substrate (phosphoethanolamine or phosphatidylethanolamine)is not yet known. We used yeast as a surrogate system to express Pfpmt and provide genetic and biochemical evidence demonstrating the specificity of Pfpmt for phosphoethanolamine in vivo. Wild-type yeast cells, which inherently lack phosphoethanolamine methylation, acquire this activity as a result of expression of Pfpmt. The Pfpmt restores the ability of a yeast mutant pem1⌬pem2⌬ lacking the phosphatidylethanolamine methyltransferase genes to grow in the absence of choline. Lipid analysis of the Pfpmt-complemented pem1⌬pem2⌬ strain demonstrates the synthesis of phosphatidylcholine but not the intermediates of phosphatidylethanolamine transmethylation. Complementation of the pem1⌬pem2⌬ mutant relies on specific methylation of phosphoethanolamine but not phosphatidylethanolamine. Interestingly, a mutation in the yeast choline-phosphate cytidylyltransferase gene abrogates the complementation by Pfpmt thus demonstrating that Pfpmt activity is directly coupled to the Kennedy pathway for the de novo synthesis of phosphatidylcholine.

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Background: Human cholesteryl ester transfer protein (CETP) transfers cholesteryl esters from high-density to low-density lipoprotein particles. Results: Crystallographic, mutagenesis, and biochemical studies illuminated inhibition mechanisms of CETP by torcetrapib and a structurally distinct compound, ((2R)-3-{[4-(4-chloro-3-ethylphenoxy)pyrimidin-2-yl][3-(1,1,2,2-tetrafluoroethoxy)benzyl]-amino}-1,1,1-trifluoropropan-2-ol. Conclusion: These small molecules inhibit CETP through blocking its lipid tunnel. Significance: Potential polar interactions at compound binding site may be utilized in design of inhibitors with improved physical properties.

Background: The high rate of mortality due to malaria and the worldwide distribution of parasite resistance to the commonly used antimalarial drugs chloroquine and pyrimethamine emphasize the urgent need for the development of new antimalarial drugs. An alternative approach to the long and uncertain process of designing and developing new compounds is to identify among the armamentarium of drugs already approved for clinical treatment of various human diseases those that may have strong antimalarial activity.

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Purpose: This study aimed to identify molecular determinants of sensitivity of non-small cell lung cancer (NSCLC) to anti-insulin-like growth factor receptor (IGF-IR) therapy.Experimental Design: A total of 216 tumor samples were investigated, of which 165 consisted of retrospective analyses of banked tissue and an additional 51 were from patients enrolled in a phase II study of figitumumab, a monoclonal antibody against IGF-IR, in stage IIIb/IV NSCLC. Biomarkers assessed included IGF-IR, epidermal growth factor receptor, IGF-II, IGF-IIR, insulin receptor substrate 1 (IRS-1), IRS-2, vimentin, and E-cadherin. Subcellular localization of IRS-1 and phosphorylation levels of mitogenactivated protein kinase and Akt1 were also analyzed.Results: IGF-IR was differentially expressed across histologic subtypes (P = 0.04), with highest levels observed in squamous cell tumors. Elevated IGF-IR expression was also observed in a small number of squamous cell tumors responding to chemotherapy combined with figitumumab (P = 0.008). Because no other biomarker/response interaction was observed using classical histologic subtyping, a molecular approach was undertaken to segment NSCLC into mechanism-based subpopulations. Principal component analysis and unsupervised Bayesian clustering identified three NSCLC subsets that resembled the steps of the epithelial to mesenchymal transition: E-cadherin high/IRS-1 low (epithelial-like), E-cadherin intermediate/IRS-1 high (transitional), and E-cadherin low/IRS-1 low (mesenchymal-like). Several markers of the IGF-IR pathway were overexpressed in the transitional subset. Furthermore, a higher response rate to the combination of chemotherapy and figitumumab was observed in transitional tumors (71%) compared with those in the mesenchymal-like subset (32%; P = 0.03). Only one epithelial-like tumor was identified in the phase II study, suggesting that advanced NSCLC has undergone significant dedifferentiation at diagnosis.Conclusion: NSCLC comprises molecular subsets with differential sensitivity to IGF-IR inhibition.

Phosphatidylcholine is the most abundant phospholipid in the membranes of Plasmodium falciparum, the agent of severe human malaria. The synthesis of this phospholipid occurs via two routes, the CDP-choline pathway, which uses host choline as a precursor, and the plant-like serine decarboxylase-phosphoethanolamine methyltransferase (SDPM) pathway, which uses host serine as a precursor. Although various components of these pathways have been identified, their cellular locations remain unknown. We have previously reported the identification and characterization of the phosphoethanolamine methyltransferase, Pfpmt, of P. falciparum and shown that it plays a critical role in the synthesis of phosphatidylcholine via the SDPM pathway. Here we provide the first evidence that the transmethylation step of the SDPM pathway occurs in the parasite Golgi apparatus. We show that the level of Pfpmt protein in the infected erythrocyte is regulated in a stage-specific fashion, with high levels detected during the trophozoite stage at the peak of parasite membrane biogenesis. Confocal microscopy revealed that Pfpmt is not cytoplasmic. Immunoelectron microscopy revealed that Pfpmt localizes to membrane structures that extend from the nuclear membrane but that it only partially co-localizes with the endoplasmic reticulum marker BiP. Using transgenic parasites expressing green fluorescent protein targeted to different cellular compartments, a complete co-localization was detected with Rab6, a marker of the Golgi apparatus. Together these studies provide the first evidence that the transmethylation step of the SDPM pathway of P. falciparum occurs in the Golgi apparatus and indicate an important role for this organelle in parasite membrane biogenesis.Malaria, the world's most important parasitic disease, is caused by intraerythrocytic protozoan parasites of the genus Plasmodium. More than 300 million clinical cases and more than 2 million deaths are reported each year with most deaths mainly caused by Plasmodium falciparum (1). Unlike other human pathogens that invade metabolically active host cells, P. falciparum invades mature erythrocytes that lack internal organelles and the metabolic pathways necessary for de novo lipid synthesis. During its intraerythrocytic life cycle, P. falciparum undergoes major metabolic and morphological changes and then divides asexually to produce up to 36 new daughter parasites (2). This rapid growth and multiplication requires active synthesis of new membranes and is fueled by lipid precursors derived from the host.Phosphatidylcholine is the major phospholipid in P. falciparum membranes, representing 50% of parasite phospholipids (for review, see Ref.3). Pharmacological studies demonstrated that inhibition of phosphatidylcholine biosynthesis is deleterious to parasite intraerythrocytic growth and multiplication, emphasizing the importance of the phospholipid metabolic pathways as possible targets for development of new antimalarial drugs (4 -10). Recent studies in P. falciparum identified two pathways of...