Heat shock protein 27 (Hsp27) is a chaperone implicated as an independent predictor of clinical outcome in prostate cancer. Our aim was to characterize changes in Hsp27 after androgen withdrawal and during androgen-independent progression in prostate xenografts and human prostate cancer to assess the functional significance of these changes using antisense inhibition of Hsp27. A tissue microarray was used to measure changes in Hsp27 protein expression in 232 specimens from hormone naive and posthormone-treated cancers. Hsp27 expression was low or absent in untreated human prostate cancers but increased beginning 4 weeks after androgen-ablation to become uniformly highly expressed in androgen-independent tumors. Androgen-independent human prostate cancer PC-3 cells express higher levels of Hsp27 mRNA in vitro and in vivo, compared with androgen-sensitive LNCaP cells. Phosphorothioate Hsp27 antisense oligonucleotides (ASOs) and small interference RNA potently inhibit Hsp27 expression, with increased caspase-3 cleavage and PC3 cell apoptosis and 87% decreased PC3 cell growth. Hsp27 ASO and small interference RNA also enhanced paclitaxel chemosensitivity in vitro, whereas in vivo, systemic administration of Hsp27 ASO in athymic mice decreased PC-3 tumor progression and also significantly enhanced paclitaxel chemosensitivity. These findings suggest that increased levels of Hsp27 after androgen withdrawal provide a cytoprotective role during development of androgen independence and that ASO-induced silencing can enhance apoptosis and delay tumor progression.

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In a search for more effective anti-diabetic treatment, we used a process coupling low-affinity biochemical screening with highthroughput co-crystallography in the design of a series of compounds that selectively modulate the activities of all three peroxisome proliferator-activated receptors (PPARs), PPAR␣, PPAR␥, and PPAR␦. Transcriptional transactivation assays were used to select compounds from this chemical series with a bias toward partial agonism toward PPAR␥, to circumvent the clinically observed side effects of full PPAR␥ agonists. Co-crystallographic characterization of the lead molecule, indeglitazar, in complex with each of the 3 PPARs revealed the structural basis for its PPAR pan-activity and its partial agonistic response toward PPAR␥. Compared with full PPAR␥-agonists, indeglitazar is less potent in promoting adipocyte differentiation and only partially effective in stimulating adiponectin gene expression. Evaluation of the compound in vivo confirmed the reduced adiponectin response in animal models of obesity and diabetes while revealing strong beneficial effects on glucose, triglycerides, cholesterol, body weight, and other metabolic parameters. Indeglitazar has now progressed to Phase II clinical evaluations for Type 2 diabetes mellitus (T2DM).adiponectin ͉ diabetes ͉ partial agonist ͉ PPAR pan-agonist ͉ Scaffold-based drug discovery T herapeutic approaches to Type 2 diabetes mellitus (T2DM), which currently affects Ϸ6% of adults in the United States (US Department of Health and Human Services, Centers for Disease Control and Prevention, Atlanta, GA; 2005), are generally polypharmaceutical in nature, targeting effects on insulin sensitivity and elements of the coincident dyslipidemia and cardiovascular diseases (1). However, polypharmacy in these treatment regimens has been cited as a potential additional risk factor (2), with many patients on 4 or more concomitant medications. A more effective strategy would be to use a single agent that possesses combined benefits from simultaneous inhibition or stimulation of several related targets, without the risks associated with combination therapy. However, optimizing activities against several targets is a complex design problem that necessitates judicious choice of targets and requires new ways in which therapeutic agents are generated.Two classes of marketed therapeutics, the fibrates (as lipidlowering agents) and the glitazones (as insulin-sensitizing drugs) target related receptors known as PPAR␣ and PPAR␥, respectively, whereas a third member of the subfamily, PPAR␦, has been the target of intense preclinical interest as an avenue for treatment of dyslipidemia (3). A pan-agonist, capable of stimulating the 3 peroxisome proliferator-activated receptors (PPARs) as a group, would be expected to be particularly useful in the treatment of T2DM from the standpoints of both efficacy and reduction in the additional risk factors associated with polypharmacy. Despite the close structural relationship between these 3 receptors, the search for compounds whi...