Tylophorine Analogs Allosterically Regulates Heat Shock Cognate Protein 70 And Inhibits Hepatitis C Virus Replication.

Tylophorine analogs have been shown to exhibit diverse activities against cancer, inflammation, arthritis, and lupus in vivo. In this study, we demonstrated that two tylophorine analogs, DCB-3503 and rac-cryptopleurine, exhibit potent inhibitory activity against hepatitis C virus (HCV) replication in genotype 1b Con 1 isolate. The inhibition of HCV replication is at least partially mediated through cellular heat shock cognate protein 70 (Hsc70). Hsc70 associates with the HCV replication complex by primarily binding to the poly U/UC motifs in HCV RNA. The interaction of DCB-3503 and rac-cryptopleurine with Hsc70 promotes the ATP hydrolysis activity of Hsc70 in the presence of the 3' poly U/UC motif of HCV RNA. Regulating the ATPase activity of Hsc70 may be one of the mechanisms by which tylophorine analogs inhibit HCV replication. This study demonstrates the novel anti-HCV activity of tylophorine analogs. Our results also highlight the importance of Hsc70 in HCV replication.

Tylophorine Analog DCB-3503 Inhibited Cyclin D1 Translation through Allosteric Regulation of Heat Shock Cognate Protein 70.

Tylophorine analog DCB-3503 is a potential anticancer and immunosuppressive agent that suppresses the translation of cellular regulatory proteins, including cyclin D1, at the elongation step. However, the molecular mechanism underlying this phenomenon remains unknown. This study demonstrates that DCB-3503 preferentially binds to heat shock cognate protein 70 (HSC70), which is a determinant for cyclin D1 translation by binding to the 3'-untranslated region (3' UTR) of its mRNA. DCB-3503 allosterically regulates the ATPase and chaperone activities of HSC70 by promoting ATP hydrolysis in the presence of specific RNA binding motifs (AUUUA) of cyclin D1 mRNA. The suppression of cyclin D1 translation by DCB-3503 is not solely caused by perturbation of the homeostasis of microRNAs, although the microRNA processing complex is dissociated with DCB-3503 treatment. This study highlights a novel regulatory mechanism of protein translation with AUUUA motifs in the 3' UTR of mRNA by HSC70, and its activity can be allosterically modulated by DCB-3503. DCB-3503 may be used to treat malignancies, such as hepatocellular carcinoma or breast cancer with elevated expression of cyclin D1.

1,2-cis Alkyl glycosides: straightforward glycosylation from unprotected 1-thioglycosyl donors.

A 1,2-cis-alkyl glycosidation protocol that makes use of unprotected phenyl 1-thioglycosyl donors is reported. Glycosylation of various functionalized alcohols was accomplished in moderate to high yield and selectivity to give the 1,2-cis-glycosides. In order to quickly develop optimum glycosylation conditions, an FIA (flow injection analysis)-ESI-TOF-MS method was developed that enabled rapid and quantitative evaluation of yield on small scale. This methodology, coupled with NMR spectroscopy, allowed for rapid evaluation of the overall reactions.

Structural evidence for inter-residue hydrogen bonding observed for cellobiose in aqueous solution.

The structure of the disaccharide cellulose subunit cellobiose (4-O-ß-D-glucopyranosyl-D-glucose) in solution has been determined via neutron diffraction with isotopic substitution (NDIS), computer modeling and nuclear magnetic resonance (NMR) spectroscopic studies. This study shows direct evidence for an intramolecular hydrogen bond between the reducing ring HO3 hydroxyl group and the non-reducing ring oxygen (O5') that has been previously predicted by computation and NMR analysis. Moreover, this work shows that hydrogen bonding to the non-reducing ring O5' oxygen is shared between water and the HO3 hydroxyl group with an average of 50% occupancy by each hydrogen-bond donor. The glycosidic torsion angles φ(H) and ψ(H) from the neutron diffraction-based model show a fairly tight distribution of angles around approximately 22(°) and -40(°), respectively, in solution, consistent with the NMR measurements. Similarly, the hydroxymethyl torsional angles for both reducing and non-reducing rings are broadly consistent with the NMR measurements in this study, as well as with those from previous measurements for cellobiose in solution.

Medicare Part D policy update and implications for 2010.

BACKGROUND: Medicare Part D has changed since its inception in 2006, with some changes defined by statute and others resulting from guidance issued by the Centers for Medicare & Medicaid Services (CMS). This article describes and catalogs the changes for 2010. OBJECTIVES: To review changes to the benefit for 2010 and interpret these changes and provide implications for plan sponsors, pharmacists, beneficiaries, and pharmaceutical companies. METHODS: We reviewed policy statements and other communications from the CMS released between January 1, 2009, and November 30, 2009, as well as any related Medicare Part D publications. RESULTS: Changes to Part D in 2010 include an update of the standard benefit design, negotiated price definition change, addition of utilization management limitations, introduction of a nonmatched National Drug Code list, and new guidance for medication therapy management programs. CONCLUSIONS: The year 2010 represents a year of favorable changes to Medicare Part D for beneficiaries. Although some patients will still face the coverage gap in the coming year, the trend toward a more robust benefit with enhanced patient protections continues.

Synthesis of a C-linked hyaluronic acid disaccharide mimetic.

The synthesis of a C-disaccharide that is designed as a mimetic for the repeating unit disaccharide of hyaluronic acid is described. The target compound was obtained via the SmI2-promoted coupling reaction of the sulfone, 2-acetamido-4,6-O-benzylidene-3-O-tert-butyldimethylsilyl-1,2-dideoxy-1-pyridinylsulfonyl-beta-D-glucopyranose (6), and the aldehyde, p-methoxyphenyl 2,3-di-O-benzyl-4-deoxy-4-C-formyl-6-O-p-methoxybenzyl-beta-D-glucopyranoside (14).

Structure-activity studies of phenanthroindolizidine alkaloids as potential antitumor agents.

Five phenanthroindolizidine alkaloids (PA) were chemically synthesized and seven were isolated from Tylophora atrofolliculata. To facilitate future drug design of phenanthroindolizidine alkaloids as potential antitumor agents, we have explored the structure-activity relationships (SAR) of this class of compounds. We demonstrated that DCB-3503 and tylophorinidine (PA-7) were among the most active compounds against tumor growth both in vitro and in vivo. In the hepatocellular carcinoma cell line HepG2, the GI(50)s of DCB-3503 and PA-7 were 35+/-5 nM and 11+/-5 nM, respectively. DCB-3503 and PA-7 significantly inhibited HepG2 tumor growth in nude mice at a dose of 9 mg/kg given by intraperitoneal (ip) injections twice a day every third day for a total of four cycles (P<0.05 for DCB-3503 and P<0.01 for PA-7). Their potent antitumor activities correlated with their potent NF-kappaB-inhibitory effects and their cyclin D1 down-regulatory effects.

Inhibition of cell growth and nuclear factor-kappaB activity in pancreatic cancer cell lines by a tylophorine analogue, DCB-3503.

A tylophorine analogue, DCB-3503, has been shown to have potent activity against tumor growth in vitro and in vivo, as well as activity in an autoimmune disease model in vivo. This study focuses on investigating the mechanisms responsible for antitumor activity of DCB-3503. The concentrations for inhibiting 50% growth/colony formation ability are 50/162 and 40/149 nmol/L for PANC-1 and HPAC cells, respectively. The growth inhibition effects are associated with DCB-3503-induced reprogramming of tumor cells. DCB-3503 could interfere with cell cycle progression. Several cell cycle regulatory proteins, including cyclin D(1), are down-regulated by DCB-3503. Using several different transcription elements coupled with a reporter gene, it was found that the nuclear factor-kappaB (NF-kappaB) signaling pathway is the most sensitive pathway mediator affected by DCB-3503. The inhibition of NF-kappaB activity is dependent on the down-regulation of nuclear phosphorylated p65, a component of the active form of the NF-kappaB complex. Such a decrease in nuclear phosphorylated p65 can be reversed by a proteosome inhibitor. Furthermore, the activity and protein expression of nuclear IkappaB kinase alpha, which is responsible for p65 phosphorylation, is suppressed and down-regulated in cells treated with DCB-3503. In summary, DCB-3503 could affect cell cycle regulatory proteins and is a potent modulator of NF-kappaB function. It is a potentially useful compound in the management of cancers in which cyclin D1 overexpression and high NF-kappaB activity play a pivotal role.