Effects of the incubation in vitro with sorbents on serum proteomic pattern and cytokines concentration in cancer patients during chemotherapy

In cancer patients, chemotherapy is often complicated by different adverse effects, which may be due either to a direct toxic effects of the administered drugs or may be mediated via the action of different cytokines, proteins or factors, whose expression is stimulated by chemotherapy. Proteomic approach, applied to the examination of plasma components, has the potentiality to single out eventual variations in the expression of a high number of proteins, by means of 2D-electrophoresis (2DE). The subsequent analysis of the amminoacydic sequence, by means of mass spectrometry (MALDI), can allow the identification of the most relevant proteic spots or constellations of spots found with 2DE. Thus, it becomes possible to identify proteic mediators, up to now unknown, linked with the adverse effects to chemotherapy, and to assess the eventual effect of protective interventions. The aim of this study was to evaluate in cancer patients the effects of chemotherapy on the serum proteomic pattern and cytokines concentration, and the eventual variations induced by the incubation in vitro of plasma with sorbents. Serum samples of three female adult patients (62-69 years), one affected by rectal cancer and two by ovarian cancer, were examined before and 4 days after the first cycle of chemotherapy with fluorouracil (one patient) and carboplatin-taxane combination (two patients). The analytical determinations demonstrated that the incubation in vitro of serum samples with sorbents totally absorbed IL-16, IL-8, MDC, MMP-3, and markedly reduced the concentration of Factor VII, IL-7, MCP-1, MIP-1a, MIP-1b, PAI-1, and RANTES. Many of these molecules are low-molecular weight proteins (LMWP). Using 2-DE with different pH ranges allowed to detect a high number of low molecular mass spots. Difference in the expression of proteins, either over- or hypo-expression, were found between normal sera and the samples of cancer patients before chemotherapy. Evident differences were also found between pre- and post-chemotherapy serum samples, particularly in the range of LMWP (MW < 66,000 D). Finally, the incubation of serum samples with sorbents induced a reduction of expression of proteins. This effect was more evident in the range of MW < 29,000 D. Some proteic spots were no more appreciable after incubation on sorbent. Within the cancer patients maps 10 spots have been chosen for identification with MALDI-TOF analysis. Proteomic analysis demonstrated that the incubation on sorbent normalizes the over-expression of some proteins induced by chemotherapy. Furthermore, the proteomic analysis of serum could allow the discovery of new biomarkers of disease and a better knowledge of pathophysiology of adverse effects of chemotherapy.