A human colonic adenoma cell line PCIAA derived from a familial polyposis coli patient was passaged in culture to form an intermediate premalignant clonogenic variant AA/Cl and, upon treatment with differentiating and carcinogenic agents, a cell line AA/Cl/SB10 which is tumourigenic in nude mice. These three mucin-secreting cell lines have been used as a model to study the changes in 0-glycan biosynthesis during the progression to cancer. Several glycosyltransferases involved in the synthesis, elongation and termination of the common 0-glycan core structures were found to decrease in the progression sequence towards adenocarcinoma. Higher activity of a number of enzymes was seen in the intermediate cell line. 0-glycan biosynthesis in the original PCIAA cell line was closest to the normal human colonic phenotype, since all four common mucin 0-glycan cores and their extended structures could be synthesized; core 3 fl-GlcNAc-transferase and a6-sialyltransferase acting on GalNAc-mucin were still detectable and core 2 P6-GlcNAc-transferase activity was accompanied by core 4 and I P6-GlcNAc-transferase activities. During progression towards adenocarcinoma, the expression of a6-sialyltransferase, core 3 fl-GlcNAc-transferase, core 4 and I P6-GlcNAc-transferases were turned off. Using monoclonal antibodies, Tn antigen, sialylTn antigen, 0-acetyl-sialomucin and sialyl-Lea determinants were not detected in secreted or cellular mucin isolated from any of the cell lines. The exposure of MUCl epitopes was seen in the malignant line, whereas sialyl-Le" determinants were found only in the premalignant PC/AA line. Sulfotransferase activities using core 1 substrate, GalPl-3GalNAca-benzy1, were high in PCIAA cells and progressively decreased upon development to adenocarcinoma, and this decrease correlated with mucin sulfation. In summary, the synthesis of less abundant, sialylated, fucosylated and extended, unbranched core 1 structures should be facilitated in the malignant cells. This is the first report of glycosyltransferase changes in human premalignant cells developing to tumourigenic cells. The data demonstrate that these cell lines are an excellent model to study the changes and regulation of mucin oligosaccharide biosynthesis during progression to cancer.The glycosylation of secreted and membrane-bound mucins is sensitive to cellular differentiation and transformation. It has previously been shown that glycosyltransferases assembling the 0-glycan chains of mucins are significantly changed in human colon cancer tissue compared to normal tissue [l]. Since there is great variability between individuals, and tissue represents a mixture of different cell types, we have now chosen cultured cell lines to study the assembly of mucin carbohydrate chains during tumour progression.Familial polyposis coli is an inherited disease in which individuals will develop colon carcinoma at a much earlier age than expected normally. Generally, most colonic carci- Np, p-nitrophenyl. noma are thought to originate from polyps and human coloni...

(2017) Clinical disposition, metabolism and invitro drug-drug interaction properties of omadacycline, Xenobiotica, 47:8, 682-696, DOI: 10.1080/00498254.2016 Omadacycline was a substrate of P-glycoprotein, but not of the other transporters. 3. Omadacycline metabolic stability was confirmed in six healthy male subjects who received a single 300 mg oral dose of [ 14 C]-omadacycline (36.6 mCi). Absorption was rapid with peak radioactivity ($610 ngEq/mL) between 1-4 h in plasma or blood. The AUC last of plasma radioactivity (only quantifiable to 8 h due to low radioactivity) was 3096 ngEq h/mL and apparent terminal half-life was 11.1 h. Unchanged omadacycline reached peak plasma concentrations ($563 ng/mL) between 1-4 h. Apparent plasma half-life was 17.6 h with biphasic elimination. Plasma exposure (AUC inf ) averaged 9418 ng h/mL, with high clearance (CL/F, 32.8 L/h) and volume of distribution (Vz/F 828 L). No plasma metabolites were observed. 4. Radioactivity recovery of the administered dose in excreta was complete (>95%); renal and fecal elimination were 14.4% and 81.1%, respectively. No metabolites were observed in urine or feces, only the omadacycline C4-epimer.

UDP-GlcNAc: GalNAc-R beta 3-GlcNAc-transferase (core 3 beta 3-GlcNAc-T, where GlcNAc is N-acetyl-D-glucosamine, GalNAc is N-acetyl-D-galactosamine and T is transferase) is expressed in a tissue-specific fashion and is high in normal colonic tissue, but downregulated in colon cancer. To further study the control of this enzyme, we examined the activity in pig, rat and human colonic tissues, and several human cancer cell lines. The enzyme was difficult to solubilize by detergents and was extremely unstable in the solubilized form. Using synthetic derivatives of the GalNAc-R substrate, we showed that the specificity of the enzyme in normal rat and human colonic mucosa requires all the substituents of the GalNAc-sugar ring of substrates for maximal activity. Core 3 beta 3-GlcNAc-T was significantly influenced by the structure of the aglycon group. None of the inactive substrate derivatives could inhibit the activity. N-Iodoacetamido-galactosamine alpha-benzyl was a weak substrate and significantly inhibited the incorporation of GLcNAc into GalNAc alpha-benzyl by human colonic homogenates. Surprisingly, none of the colonic cancer cell lines or any other cancer and leukaemia cells examined exhibited detectable activity of the enzyme, although a number of other glycosyltransferase activities involved in O-glycan biosynthesis were active. Mixing experiments did not reveal an endogenous inhibitor in HL60 cells or an activator of core 3 beta 3-GlcNAc-T in human colonic mucosa. Thus, the lack of core 3 beta 3-GlcNAc-T in human colonic mucosa. Thus, the lack of core 3 beta 3-GlcNAc-T activity in cancer cell lines may be due to cell transformation or cell culturing.

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Renal transplant recipients exhibit variability in mycophenolic acid (MPA) and MPA glucuronide (MPAG) pharmacokinetics, which are influenced by clinical and demographic factors. Racial influence on MPA and MPAG pharmacokinetics was investigated in 53 patients: 17 African American males, 22 Caucasian males, and 14 females receiving mycophenolate mofetil (MMF) and cyclosporine. A 12-hour steady-state pharmacokinetic study was conducted. Enterohepatic circulation of MPA was characterized by a second plasma concentration peak and was included in a novel statistical model with MPAG. MPA clearance in African American males was 26.5 ± 14.4 L/h versus 17.9 ± 6.1 L/h in Caucasian males (P = .035) and 16.1 ± 4.6 L/h in Caucasian females (P = .024) with no difference noted in MPA troughs. Enterohepatic circulation occurred less frequently in African American males (23%) compared with Caucasian males (42%) and Caucasian females (50%) (P > .05). Cyclosporine exposure was correlated with MPA and MPAG pharmacokinetics, whereas creatinine clearance influenced MPAG pharmacokinetics. A racial difference was noted with more rapid MPA clearance in African American males compared with Caucasians. The results support differential MPA dosing and the role of therapeutic drug monitoring in addition to considering the influence of renal function and concurrent immunosuppressives on MPA and MPAG pharmacokinetics.