Examples of mature PCDD projects:

1. Inhibitors of Phosphatidylcholine Transfer Protein
Diseases: Diabetes and Atherosclerosis
PI: David E. Cohen (BWH)

Project Description:  Phosphatidylcholine transfer protein (PC-TP) is a 25 kD cytosolic lipid binding protein that is highly expressed in liver and macrophages and catalyzes the transfer of phosphatidylcholines between membranes in vitro. Research in the Cohen laboratory has demonstrated that PC-TP regulates hepatic lipid and glucose metabolism. Mice lacking PC-TP (Pctp-/-) are sensitized to insulin action. In addition, PC-TP-deficient mice are protected against atherosclerosis. Because it is such a highly specific lipid binding protein, these in vivo observations strongly suggest that PC-TP might be a highly attractive molecular target for a novel therapy in diabetes and atherosclerosis. A high throughput assay to measure PC-TP activity was developed at the PCDD and used to screen 130,000 compounds. From these efforts two compound series were selected for optimization studies, which are continuing.

Reference: Wagle, N.; Xian, J.; Shishova, E.Y.; Wei, J.; Glicksman, M.A.; Cuny, G.D.; Stein, R.L.; Cohen, D.E. “Small Molecule Inhibitors of Phosphatidylcholine Transfer Protein/StarD2 Identified by High Throughput Screening” Anal. Biochem. 2008, 383, 85 – 92.

2. Inhibitors of BMP signaling pathway 
Diseases: Fibrodysplasia ossificans progressiva (FOP) and anemia of inflammation.
PI: Randall Peterson (MGH), Kenneth Bloch (MGH) and Paul Yu (MGH)

Project Description:  Bone morphogenetic protein (BMP) signaling is important through its control on gene transcription, cell differentiation and cell proliferation.  BMP cell signaling is mediated through a combination of two classes of receptor kinases, termed type I (ALK2, ALK3 and ALK6) and type II (BMPRII, ActRIIa, and ActRIIb).  Following BMP receptor binding, the kinase domain of the type I component phosphorylates SMAD1/5/8, which serves as gene regulators.  Aberrant BMP signaling is associated with a variety of diseases.  Several conditions (i.e. fibrodysplasia ossificans progressiva and anemia of inflammation) are associated with a gain-of-function in BMP signaling and might be treatable with an inhibitor of BMP signaling.  A medicinal chemistry project was launched to prepare derivatives of dorsomorphin, a moderately potent BMP signaling inhibitor discovered by Peterson, Bloch and Yu, to increase potency and selectivity and to optimize its pharmaceutical properties. A potent and metabolically stable analog has been identified (LDN-193189) with an EC50 = 5 nM for inhibition of SMAD1/5/8 phosphorylation, a LogD of 2.2, solubility of 1.21 mg/mL in phosphate buffer, in vitro t1/2 in mouse liver microsomes of 82 min, in vivo t1/2 of 1.6 h in mouse following bolus intraperitoneal administration, and has been dose at 3 mg/kg/day in mice for > 6 weeks with no observable signs of toxicity.  This compound has also demonstrated efficacy in animal models of FOP and anemia of inflammation.

References: (a) Yu, P.B.; Deng, D.Y.; Lai, C.S.; Hong, C.C.; Cuny, G.D.; Bouxsein, M.L.; Peterson, R.T.; Katagiri, T.; Fukuda, T.; Mishina, Y.; Bloch, K.D. “BMP type I receptor inhibition reduces heterotopic ossification” Nat. Med. 2008, 14, 1363 – 1369. (b) Cuny, G. D.; Yu, P.B.; Laha, J.K.; Xing, X.; Liu, J.-F.; Lai, C.S.; Deng, D.Y.; Sachidanandan, C.; Bloch, K. D.; Peterson, R. T. “Structure activity relationship study of bone morphogenetic protein (BMP) signaling inhibitors” Bioorg. Med. Chem. Lett. 2008, 18, 4388 – 4392.

3. Novel anesthetic agents
Disease: Anesthesia during surgery.
PI: Douglas Raines (MGH); Stuart Forman (MGH)

Project Description:  Etomidate is an imidazole-based intravenous sedative/general anesthetic agent that is distinguished by its ability to maintain hemodynamic stability in sick, elderly, and traumatized patients.  However because etomidate potently inhibits the P450 enzyme 11 beta-hydroxylase, leading to prolonged suppression of adrenocortical steroid synthesis with potentially fatal consequences, its clinical use is effectively limited to single bolus administration for the induction of anesthesia.  The goal of the project is to develope structural analogues of etomidate that produce sedation/general anesthesia but lack the ability to inhibit adrenocortical function.  A medicinal chemistry project was launched to prepare derivatives of etomidate.  An analog has been identified that is ~ 2.5-times less potent as an anesthesia then etomidate, but does not show inhibition of adrenocortical function at the efficatious dose.  Currently, efforts are being made to determine a therapeutic index for this analog and to continue studying its anasthetic properties.

4.  Inhibitors of Haspin Kinase
Disease: Cancer
PI: Jonathan M.G Higgins (BWH)

Project Description:  The mechanisms that regulate chromosome segregation in mitosis are vital to understand how cancer develops, and to discover new ways to prevent and treat cancer. Recently new selective anti-mitotic drugs such as aurora kinase inhibitors have shown great promise in pre-clinical experiments and there is much interest in identifying new drug targets in mitosis. Prof. Higgins recently identified haspin as a novel kinase required for mitosis. Similar to other mitotic kinases such as Polo-like kinase-1 and the aurora kinases, haspin represents a new target for the development of targeted anti-mitotic cancer therapeutics.  An enzyme based assay using full length haspin kinase was developed at PCDD. Histone H3 peptide (1-21) is used as the substrate and detection is done by Homogeneous Time Resolve Fluorescence (LANCE). Hits were retested with natural full length histone as the substrate in a 33P-ATP radioactive assay. In addition, promising hits are evaluated in a cellular assay to determine the inhibition of H3T3 phosphorylation and their ability to block mitosis.  Currently, two structure series of inhibitors are being optimized and studies in various cellular and cancer models.

Reference: Patnaik, D.; Xian, J.; Glicksman, M.A.; Cuny, G.D.; Stein, R.L.; Higgins, J.M.G. “Identification of small molecule inhibitors of the mitotic kinase Haspin by high throughput screening using a homogenous Time-Resolved Fluorescence Resonance Energy Transfer assay” J. Biomol. Screen. 2008, 13, 1025 – 1034.