Biphenyl Gal and GalNAc FmlH Lectin Antagonists of Uropathogenic E. coli (UPEC): Optimization through Iterative Rational Drug Design.

The F9/Yde/Fml pilus, tipped with the FmlH adhesin, has been shown to provide uropathogenic Escherichia coli (UPEC) a fitness advantage in urinary tract infections (UTIs). Here, we used X-ray structure guided design to optimize our previously described ortho-biphenyl Gal and GalNAc FmlH antagonists such as compound 1 by replacing the carboxylate with a sulfonamide as in 50. Other groups which can accept H-bonds were also tolerated. We pursued further modifications to the biphenyl aglycone resulting in significantly improved activity. Two of the most potent compounds, 86 (IC50 = 0.051 µM) and 90 (IC50 = 0.034 µM), exhibited excellent metabolic stability in mouse plasma and liver microsomes but showed only limited oral bioavailability (<1%) in rats. Compound 84 also showed a good pharmacokinetic (PK) profile in mice after IP dosing with compound exposure above the IC50 for 6 h. These new FmlH antagonists represent new antivirulence drugs for UTIs.

Abnormal accumulation and recycling of glycoproteins visualized in Niemann-Pick type C cells using the chemical reporter strategy.

Niemann-Pick type C (NPC) disease is characterized by impaired cholesterol efflux from late endosomes and lysosomes and secondary accumulation of lipids. Although impaired trafficking of individual glycoproteins and glycolipids has been noted in NPC cells and other storage disorders, there is currently no effective way to monitor their localization and movement en masse. Using a chemical reporter strategy in combination with pharmacologic treatments, we demonstrate a disease-specific and previously unrecognized accumulation of a diverse set of glycoconjugates in NPC1-null and NPC2-deficient fibroblasts within endocytic compartments. These labeled vesicles do not colocalize with the cholesterol-laden compartments of NPC cells. Experiments using the endocytic uptake marker dextran show that the endosomal accumulation of sialylated molecules can be largely attributed to impaired recycling as opposed to altered fusion of vesicles. Treatment of either NPC1-null or NPC2-deficient cells with cyclodextrin was effective in reducing cholesterol storage as well as the endocytic accumulation of sialoglycoproteins, demonstrating a direct link between cholesterol storage and abnormal recycling. Our data further demonstrate that this accumulation is largely glycoproteins, given that inhibitors of O-glycan initiation or N-glycan processing led to a significant reduction in staining intensity. Taken together, our results provide a unique perspective on the trafficking defects in NPC cells, and highlight the utility of this methodology in analyzing cells with altered recycling and turnover of glycoproteins.

D-galactose receptor-targeted in vivo spectral fluorescence imaging of peritoneal metastasis using galactosamin-conjugated serum albumin-rhodamine green.

The wavelength resolved spectral fluorescence imaging technique using a fluorescein-conjugated avidin has been reported to visualize submillimeter implants of ovarian cancer because of its highly targeted and quickly cleared pharmacokinetics. However, clinical application of avidin was hampered by its strong immunogenicity. As a clinically feasible alternative to avidin, which targets the same D-galactose receptor but is made from a nonimmunogenic source, with even better binding capability by multiplying binding sites but still maintaining a favorable characteristic of high isoelectric point, a serum albumin conjugated with 23 galactosamine and 2 rhodamine green molecules (GmSA-RhodG) was designed and synthesized. GmSA-RhodG showed more than 10-fold rapid and higher uptake by SHIN3 ovarian cancer cells than both avidin- and no galactosamine-conjugated albumin (bovine serum)-RhodG. Sensitivity and specificity of GmSA-RhodG to detect red fluorescence labeled peritoneal cancer foci in mouse cancer model were 100%/99% (n=566), respectively for approximately 1-mm lesions and even smaller lesions were detected in vivo. These results indicate that GmSA-RhodG is not only a clinically feasible alternative but more efficient targeting reagent for D-galactose receptors than avidin-RhodG.

Two-color in vivo dynamic contrast-enhanced pharmacokinetic imaging.

Optical imaging is unique among in vivo imaging methods because it is possible to simultaneously resolve two or more probes emitting at different wavelengths of light. We employed two near-infrared (NIR) fluorescent optical probes, each labeled with a different protein, to simultaneously evaluate the pharmacokinetics of each probe. Dynamic optical imaging was performed in live mice after the coinjection of bovine serum albumin (BSA) and galactosamine-conjugated bovine serum albumin (GmSA) labeled with either Cy5.5 or Cy7 NIR dyes. The pharmacokinetics of BSA and GmSA were independently and simultaneously visualized. Next, two-color dynamic imaging of biotinylated BSA (b-BSA) and BSA labeled with Cy5.5 or Cy7 was performed before and after an avidin "chase." Following avidin injection, fluorescently labeled b-BSA rapidly accumulated in the liver, while minimal liver uptake of BSA was noted. Thus, multicolor dynamic contrast-enhanced optical imaging can be performed to noninvasively track the pharmacokinetics of different proteins. This imaging technique can be applied to a wide variety of optically labeled proteins in order to simultaneously track their biodistribution.

Hepatic drug targeting: phase I evaluation of polymer-bound doxorubicin.

PURPOSE: Preclinical studies have shown good anticancer activity following targeting of a polymer bearing doxorubicin with galactosamine (PK2) to the liver. The present phase I study was devised to determine the toxicity, pharmacokinetic profile, and targeting capability of PK2. PATIENTS AND METHODS: Doxorubicin was linked via a lysosomally degradable tetrapeptide sequence to N-(2-hydroxypropyl)methacrylamide copolymers bearing galactosamine. Targeting, toxicity, and efficacy were evaluated in 31 patients with primary (n = 25) or metastatic (n = 6) liver cancer. Body distribution of the radiolabelled polymer conjugate was assessed using gamma-camera imaging and single-photon emission computed tomography. RESULTS: The polymer was administered by intravenous (i.v.) infusion over 1 hour, repeated every 3 weeks. Dose escalation proceeded from 20 to 160 mg/m(2) (doxorubicin equivalents), the maximum-tolerated dose, which was associated with severe fatigue, grade 4 neutropenia, and grade 3 mucositis. Twenty-four hours after administration, 16.9% +/- 3.9% of the administered dose of doxorubicin targeted to the liver and 3.3% +/- 5.6% of dose was delivered to tumor. Doxorubicin-polymer conjugate without galactosamine showed no targeting. Three hepatoma patients showed partial responses, with one in continuing partial remission 47 months after therapy. CONCLUSION: The recommended PK2 dose is 120 mg/m(2), administered every 3 weeks by IV infusion. Liver-specific doxorubicin delivery is achievable using galactosamine-modified polymers, and targeting is also seen in primary hepatocellular tumors.

Preliminary clinical study of the distribution of HPMA copolymers bearing doxorubicin and galactosamine.

Galactose-targeted delivery of macromolecules and drug conjugates to asialoglycoprotein receptor (ASGPR) positive cells has been widely documented in animals, although targeting in humans has never been demonstrated. In this study we report the pharmacokinetics and imaging determined in the first patient enrolled in a phase I clinical study of the poly[N-(2-hydroxypropyl)methacrylamide] copolymer bearing doxorubicin and galactosamine, known as PK2. Gradient high performance liquid chromatography (HPLC) evaluation of plasma and urine has been combined with 123I-based imaging to show biphasic clearance of the drug from the plasma (half-lives of 78+/-1 and 990+/-15), and approximately 30% delivery of the drug to the hepatic region, as determined by planar whole body imaging at 24 h. This patient has a multifocal hepatoma, and single photon emission computed tomography (SPECT) analysis showed a ratio of tumour tissue to normal liver uptake of approximately 1:3, at 24 h. On the basis of this patient, effective hepatic targeting can be achieved following an intravenous dose of 20 mg/m2 doxorubicin as PK2, however the therapeutic usefulness of this targeted drug has yet to be established.

Targeting of N-(2-hydroxypropyl)methacrylamide copolymer-doxorubicin conjugate to the hepatocyte galactose-receptor in mice: visualisation and quantification by gamma scintigraphy as a basis for clinical targeting studies.

N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers containing doxorubicin and galactosamine have been developed to target the hepatocyte galactose receptor with the aim of organ-specific chemotherapy of primary and metastatic liver disease. Previous biodistribution studies in rats and mice have used tyrosinamide incorporated into the copolymer structure to permit labelling with 125I, enabling quantification of polymer distribution by dissection analysis. Radiolabelling of this copolymer with 131I, a radionuclide suitable for gamma scintigraphy, and the imaging analysis of its biodistribution in mice are reported. The present studies are the first to confirm the feasibility of imaging HPMA copolymer biodistribution, and such gamma scintigraphy will be of great value for clinical pharmacokinetic studies with this compound. Gamma scintigraphy is virtually the only non-invasive method of assessing hepatic uptake of this and similar materials.

[The antitoxic function of the liver in D-galactosamine poisoning]. / Antitoksicheskaia funktsiia pecheni pri intoksikatsii D-galaktozaminom.

Two intragastric administrations of 500 mg/kg of D-galactosamine reduce the RNA and the cytochrome P-45, and b5 content in the hepatic microsomes of rats; inhibit the activity of aminopyrine-N-demethylase, hexobarbital hydroxylase, aniline-p-hydroxylase, and glutathione-S-transferase; reduce the rate of NADP.H and NAD.H oxidation; accelerate inactivation of cytochrome P-450 to cytochrome P-420; reduce the number of points of hexobarbital binding with N-octilamine, though increase the hemoprotein affinity to these substrates. Destruction of the nucleus, endoplasmic reticulum, and mitochondria occurs in the hepatocytes of D-galactosamine poisoned rats.