Inhibitions of several antineoplastic drugs on serum sialic Acid levels in mice bearing tumors

Analysis of Lycobetaine in Rat Plasma by LC-ESI-MS/MS

In this study, a selective and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometric method was developed and validated for the determination of lycobetaine in rat plasma. Berberine was selected as the internal standard, and rat plasma samples were pretreated via protein precipitation and further separated on a diamonsil octadecyl-silylated silica column using 0.2% (v/v) aqueous formic acid and methanol as the mobile phase. Selected reaction monitoring was performed using the transitions m/z 266.1 → 208.1 and m/z 336.1 → 320.0 to determine the concentrations of lycobetaine and internal standard, respectively. The injection volume was 1 µL, and the calibration curve was linear (R2 = 0.9998), while the validated lower limit of quantification was 25 ng/mL. Precision varied from 3.4% to 9.9%, and accuracy varied from -2.6% to 8.7%. Lycobetaine remained stable under all relevant analytical conditions tested in the study. The method was successfully applied to determine the plasma concentration of lycobetaine in a pharmacokinetic study. After intravenous administration of 10 mg/kg and oral administration of 200 mg/kg lycobetaine in rats, the pharmacokinetic parameters were calculated and the oral bioavailability of lycobetaine was determined as 7.30% ± 1.44%.

Sialylation: an Avenue to Target Cancer Cells

Tumorigenesis and metastasis are frequently associated with altered structure and expression of oligosaccharides on cell surface glycoproteins and glycolipids. The expression of sialylated glycoconjugates has been shown to change during development, differentiation, disease and oncogenic transformation. Abnormal sialylation in cancer cell is a distinctive feature associated with malignant properties including invasiveness and metastatic potential. The alterations in sialylation is accompanied by changes in sialic acid, sialidase activity, sialyltransferase (ST) activity or sialoproteins. The present review summarizes the reports on alterations of sialic acid, linkage specific STs and sialoproteins, sialidase activity together with different subtypes of ST and sialidases mRNA expressions in various cancers like lung, breast, oral, cervical, ovarian, pancreatic etc. Sialic acids are widely distributed in nature as terminal sugars of oligosaccharides attached to proteins or lipids. The increase shedding of sialic acid observed in malignant tumors may be due to different types of sialidases. The amount of sialic acid is governed by levels of sialidases and STs. Various types of STs are also involved in formation of different types sialylated tumor associated carbohydrate antigens which plays important role in metastasis. The alterations associated with sialylation aids in early diagnosis, prognosis and post treatment monitoring in various cancers. Recently newer drugs targeting different interplays of sialylation have been developed, which might have profound effect in inhibiting sialylation and thus cancer metastasis and infiltration.