Colorectal cancer biomarker discovery and validation using LC-MS/MS-based proteomics in blood: truth or dare?

Globally, colorectal cancer (CRC) is the third most common malignant neoplasm. However, highly sensitive, specific, noninvasive tests that allow CRC diagnosis at an early stage are still needed. As circulatory blood reflects the physiological status of an individual and/or the disease status for several disorders, efforts have been undertaken to identify candidate diagnostic CRC markers in plasma and serum. In this review, the challenges, bottlenecks and promising properties of mass spectrometry (MS)-based proteomics in blood are discussed. More specifically, important aspects in clinical design, sample retrieval, sample preparation, and MS analysis are presented. The recent developments in targeted MS approaches in plasma or serum are highlighted as well.

Neuropeptide biology in Drosophila.

Drosophila melanogaster is since decades the most important invertebrate model. With the publishing of the genome sequence, Drosophila also became a pioneer in (neuro)peptide research. Neuropeptides represent a major group of signaling molecules that outnumber all other types of neurotransmitters/modulators and hormones. By means of bioinformatics 119 (neuro)peptide precursor genes have been predicted from the Drosophila genome. Using the neuropeptidomics technology 46 neuropeptides derived from 19 of these precursors could be biochemically characterized. At the cellular level, neuropeptides usually exert their action by binding to membrane receptors, many of which belong to the family of G-protein coupled receptors or GPCRs. Such receptors are the major target for many contemporary drugs. In this chapter, we will describe the identification, localization and functional characterization of neuropeptide-receptor pairs in Drosophila melanogaster.

Unraveling the protective effect of a Drosophila phosphatidylethanolamine-binding protein upon bacterial infection by means of proteomics.

This study addresses the biological function of CG18594, a Drosophila melanogaster phosphatidylethanolamine-binding protein (PEBP) that we named PEBP1, by combining fly genetics, survival experiments and differential proteomics. We demonstrate that transgenic flies overexpressing PEBP1 are highly protected against bacterial infection due to the release of immunity-related proteins in their hemolymph. Apart from proteins that have been reported earlier to participate in insect immunity, we also identify proteins involved in metabolism and signaling, and, in addition, twelve (hypothetical) proteins with unknown function. This is the first report demonstrating an immune function for a Drosophila PEBP protein.

How functional genomics and genetics complements insect endocrinology.

Insects are the most abundant animal group on Earth and have been the subject of genetic and physiological studies since the beginning of the 19th century. The public interest in understanding their biology increased as many insects have proven to exert a severe impact on human welfare and the environment. To trigger insect physiological and endocrinological research, the genome of several economical and ecological important insect species was recently sequenced. Following the availability of these genomic data many so called 'post-genomic' technologies have been developed to characterise gene function and to unravel signalling pathways underlying biological processes. For some species genomic research is further complemented with mutagenesis and reverse genetic studies. In the following, we present an overview of genomic and functional genetic methodologies that boosted endocrine research in insects.