Fucosyl monosialoganglioside: Quantitative analysis of specific potential biomarkers of lung cancer in biological matrices using immunocapture extraction/tandem mass spectrometry

RATIONALE

Certain lung cancer patients express elevated Fucosyl Monosialoganglioside (Fuc-GM1) in circulation compared to control groups. Several sensitive methods involving characterization of Fuc-GM1 have been reported. However, a highly specific and sensitive method for quantifying multiple potential Fuc-GM1 biomarkers present in various biological matrices has not been reported to date.

METHODS

Individual Fuc-GM1 analogs in a commercially obtained standard mixture were characterized using HPLC/UV/MS and high-resolution mass spectrometry (HRMS). Proprietary antibodies, mAb1 and mAb2, were used to selectively capture and pre-concentrate the soluble and drug-bound forms of Fuc-GM1 molecules present in human serum and whole blood, eliminating the background matrix components. Immunocapture extraction (ICE) followed by HPLC/MS/MS was used to quantify specific Fuc-GM1 analogs in biological matrices.

RESULTS

The concentration of individual Fuc-GM1 analogs in the standard mixture was estimated to be 7-34%, using HPLC/UV/MS. Using the standard mixture spiked into the biological matrices (100 μL), the lower limit of quantification (LLOQ) of each analog was 0.2-0.4 ng/mL with a dynamic range of up to 200 ng/mL. The applicability of the ICE-HPLC/MS/MS method was demonstrated by detecting endogenous Fuc-GM1 analogs present in rat blood and in several lung cancer cell lines.

CONCLUSIONS

This highly specific and sensitive HPLC/MS/MS method for quantifying individual potential Fuc-GM1 biomarkers in serum and whole blood can play a critical role in patient stratification strategies and during drug treatment. This method can be employed for monitoring both free (soluble) form and antibody drug-bound Fuc-GM1.

Dramatic elevation in urinary amino terminal titin fragment excretion quantified by immunoassay in Duchenne muscular dystrophy patients and in dystrophin deficient rodents

Enzyme-linked and electrochemiluminescence immunoassays were developed for quantification of amino (N-) terminal fragments of the skeletal muscle protein titin (N-ter titin) and qualified for use in detection of urinary N-ter titin excretion. Urine from normal subjects contained a small but measurable level of N-ter titin (1.0 ± 0.4 ng/ml). A 365-fold increase (365.4 ± 65.0, P = 0.0001) in urinary N-ter titin excretion was seen in Duchene muscular dystrophy (DMD) patients. Urinary N-ter titin was also evaluated in dystrophin deficient rodent models. Mdx mice exhibited low urinary N-ter titin levels at 2 weeks of age followed by a robust and sustained elevation starting at 3 weeks of age, coincident with the development of systemic skeletal muscle damage in this model; fold elevation could not be determined because urinary N-ter titin was not detected in age-matched wild type mice. Levels of serum creatine kinase and serum skeletal muscle troponin I (TnI) were also low at 2 weeks, elevated at later time points and were significantly correlated with urinary N-ter titin excretion in mdx mice. Corticosteroid treatment of mdx mice resulted in improved exercise performance and lowering of both urinary N-ter titin and serum skeletal muscle TnI concentrations. Low urinary N-ter titin levels were detected in wild type rats (3.0 ± 0.6 ng/ml), while Dmd^mdx rats exhibited a 556-fold increase (1652.5 ± 405.7 ng/ml, P = 0.002) (both at 5 months of age). These results suggest that urinary N-ter titin is present at low basal concentrations in normal urine and increases dramatically coincident with muscle damage produced by dystrophin deficiency. Urinary N-ter titin has potential as a facile, non-invasive and translational biomarker for DMD.

Abstract 3802: Selective cytotoxicty and mechanism of Myrothamnus flabellifolius, an edible medicinal plant, on acute myeloid leukemia cells

Current therapies for acute myeloid leukemia involve chemotherapy and radiation, which cause damage to normal and cancerous cells. There is a dire need to discover novel drugs that target only cancer cells. Myrothamnus flabellifolius is a South African resurrection plant known for its anti-viral, anti-microbial and anti-inflammatory properties. Human myeloid leukemia (HL-60) cells and normal (TK-6) lymphocytes were treated with the methanolic extract of M. flabellifolius. Cancer cells treated with extract depicted a significant reduction in viability as compared to normal cells. The first part of this project involved fractionation of the methanolic extract using HPLC and testing each fraction on the normal and leukemic cell lines to find a fraction that selectively killed the cancer cells. A phytochemical analysis was also conducted for characterization of the anticancer compounds. In terms of mechanism, the loss in HL-60 viability was accompanied by the induction of caspase dependent apoptosis by way of caspase-7 cleavage. Heat shock proteins are molecular chaperones that aid in protein reassembly under stressful conditions and protect cells from apoptosis. TK-6 cells express heat shock protein 70 at a high level while HL-60 cells do not express the protein under normal conditions. The expression of HSP70 exhibits a positive correlation with the viability of cells post treatment with extract, indicating that this vital protein plays an important role in the survival of cells post treatment with M. flabellifolius extract.

Citation Format: Abeer Badiab, Jasjit Dhillon, Fizal Nabbie, Bela Peethambaran. Selective cytotoxicty and mechanism of Myrothamnus flabellifolius, an edible medicinal plant, on acute myeloid leukemia cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3802. doi:10.1158/1538-7445.AM2015-3802

Immunoassay-based measurement of clinical biomarkers for monitoring changes in nasal cavity

BACKGROUND

Many drugs for treatment of allergies, migraine headaches, inflammation, and other indications are administered into the nasal cavity providing access to the immune and central nervous systems. One of the concerns for using this route of administration is potential damage to the nasal epithelium and mucosal regions. We assembled a panel of clinical biomarkers that can be used to monitor changes in the nasal epithelium, mucosa, and olfactory regions in preparation for clinical trials involving drugs administered via intranasal route. These biomarkers included albumin, elastase, IL-6, IL-8, lactoferrin, myeloperoxidase and nerve growth factor.

METHODS

Immunoassays were developed and used to measure changes in these biomarkers in nasal lavage samples collected twice daily from 30 assumed-healthy volunteers over a 2-day period. Various statistical methods including analysis of variance (ANOVA), paired t-test and Pearson's product-moment correlation were used to evaluate the data.

RESULTS

Although the basal levels of these biomarkers were varied among subjects, the data show that the concentrations of albumin, elastase and IL-8 were significantly higher in samples collected in the morning compared to samples collected later during the day. Pre-washing nasal cavity prior to collecting nasal lavage samples did alter the measurement of elastase and albumin, but did not influence the levels of the other biomarkers.

CONCLUSIONS

These data show that this panel of biomarkers can be used to monitor changes in the nasal cavity including those affected by diurnal fluctuations. These results also provide useful baseline values and sources of variability for each biomarker that could be used to help design clinical trials.

Determination of metformin in plasma by high-performance liquid chromatography after ultrafiltration

A rapid high-performance liquid chromatography (HPLC) method was developed for determination of metformin, an oral antidiabetic agent, in plasma. Sample preparation entailed a 30-min centrifugation of plasma through a micron filter with direct injection of the protein-free ultrafiltrate into an HPLC system consisting of a cation-exchange extraction column (7.5x4.6 mm), a column switching valve, and a cation-exchange analytical column (250x4.6 mm). The eluent was monitored at 232 nm. Metformin was well resolved at a retention time of about 5 min. There was less than 2% loss of metformin during ultrafiltration and good linearity was established from 0.10 to 40 mg/l of metformin hydrochloride. The lower limit of quantitation was about 0.05 mg/l, at which concentration the signal-to-noise was above 10. The intra- and inter-assay coefficients of variation at plasma concentrations of metformin hydrochloride between 0.25 and 25 mg/l were typically 0.8-1.4% and 3.5-6.4%, respectively. This method offers a rapid sample preparation time and achieves excellent sensitivity without resorting to extraction and evaporation techniques.