4_6-7/2010Cover Picture: Proteomics – Clinical Applications 6/10

Wolf in sheep's clothing or sheep in wolf's clothing

Proteomic studies had shown that breast cancer cells express much higher levels of TrkA (tyrosine kinase receptor, a neurotrophin) than did normal tissue. Furthermore, the in vitro invasiveness and in vivo metastatic capability of breast tumor cells were enhanced. To find out which proteins were involved in the enhancement, Lagadec et al. applied classic proteome techniques: 2-DE, MALDI-TOF and LC-MS/MS. Of the ∼1500 spots resolved, more than 20 were up- or down-regulated. In TrkA overexpressing cells, protein Ku86 was also found at increased levels, Western blots validating 2-DE and MS findings. Ku86 mRNA levels remained unchanged however. Ku proteins seem to be of the mobile sort - involved in cell migration, proliferation and invasion. Ku70 has been reported to stimulate cancer cell survival in the face of apoptosis. Thus, both Ku86 and Ku70 can help normal or cancer cells survive and grow.

Lagadec, C. et al., Proteomics Clin. Appl. 2010, 4, 580–590.

Antibody microarray proteomes segregate glioblastoma multiforme types

Glioblastoma multiforme (GBM), the most frequent and aggressive brain tumor type, does not appear to be a single disease on close examination. It shows a great deal of molecular heterogeneity and a “stealth” mechanism of infection that causes difficulty in selecting an appropriate therapy. Most therapies do not do much more than add a few days of survival except for some autoimmune therapies, which may give a 60% extension of survival. Getting such extensions is highly variable. Carlsson et al. took it as a challenge to adapt their earlier microarray technology for the analysis of GBM. Working with 18 GBMpatients and 17 controls, they prepared biotin-labelled serum samples and Alexa-647-labelled streptavidin detection reagents. The detection array comprised 138 human scFv antibodies against 60 different antibodies. After statistical analysis, it was clear that the binding information was sufficient to distinguish the patients that would benefit from immunotherapy.

Carlsson, A. et al., Proteomics Clin. Appl. 2010, 4, 591–602.

Looking for the end of the rainbow

About 30% of the time after a heart attack (MI), the heart attempts to reconstruct damaged areas, such as left ventricular remodeling (LVR) after damage to an anterior wall, but the result is usually ischemic heart failure. Fertin et al. used combinatorial peptide ligand library (CPLL) and SELDITOF-MS technology to minimize abundance disparity problems - too much albumin, too little of low abundance factors. Analyzing CPLL profiles from samples taken 4 times in the course of a year (at 0, 1, 3, and 12 months), 73 peaks exhibited modulation that correlated with the degree of remodeling. Interestingly, serum and plasma from the same patient did not correlate except in two cases. Most of the peaks could only be identified when treated by CPLL before SELDI-TOF-MS.

Fertin, M. et al., Proteomics Clin. Appl. 2010, 4, 654–673.

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