Mass spectrometry study of hemoglobin‐oxaliplatin complexes in colorectal cancer patients and potential association with chemotherapeutic responses

Abstract

Oxaliplatin is the most active platinum (Pt)-containing anticancer drug for the treatment of advanced colorectal cancer. We report here the study of potential association of the levels of oxaliplatin-protein complexes in 19 cancer patients with treatment efficacy using size-exclusion high-performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC/ICPMS) and nanoelectrospray ionization mass spectrometry (nanoESI-MS) techniques. Blood samples from 19 colorectal cancer patients were collected at 1 and 48 h after the first infusion of oxaliplatin. HPLC/ICPMS quantification of the oxaliplatin-protein complexes showed that the levels of Pt-protein complexes in plasma samples at 48 h were reduced by approximately 50% compared to those at 1 h, whereas those in hemolysates did not change significantly. The concentrations of hemoglobin (Hb)-oxaliplatin complexes determined by HPLC/ICPMS ranged from 3.1 to 8.7 microM. NanoESI-MS analysis of the patient hemolysates showed three distinct mass spectral profiles of the Hb-oxaliplatin complexes: (1) 1:1, (2) 1:1 with 1:2, and (3) multiple complexes of 1:1, 1:2, 1:3, and 1:4, corresponding to the Hb-oxaliplatin complex concentrations determined by HPLC/ICPMS. Potential association of variables including Hb-oxaliplatin complex concentrations with time to progress as the treatment efficacy indicator was analyzed using the Cox model. Multivariate analysis of the potential predictors showed that the statistically significant variables were Hb-oxaliplatin complex concentration (p = 0.02), performance status (p = 0.02), baseline neutrophil count (p = 0.05), and the site of the primary cancer (colon vs. rectal, p = 0.01). The hazard ratio for the concentration of the Hb-oxaliplatin complexes was 2.4, suggesting that the risk of cancer progression significantly increased with increasing of Hb-oxaliplatin complexes in patients. These results demonstrate that the level of the Hb-oxaliplatin complexes in erythrocytes is a potential biomarker for indicating inter-patient variations in oxaliplatin treatment efficacy.

Hyphenated techniques as tools for speciation analysis of metal-based pharmaceuticals: developments and applications

“…This was demonstrated after SEC separation by the simultaneous detection of platinum and iron, as the loss of the heme group resulted in a decrease in the Hb peak area as monitored by the iron isotope 57 Fe using ICP-MS detection [64]. Furthermore, the interactions of other platinum species with Hb were investigated by the same group, which led to the discovery of structural changes in the heme group [65,66].…”

Quantification of Noble Metals in Biological and Environmental Samples

“…Investigation of the interaction of platinum drugs with blood proteins, albumin, and transferrin [159]; oxaliplatin with hemoglobin in blood samples of colorectal cancer patients [160]; the adducts of ZD 0743 with urine proteins [161]; and cisplatin, transplatin, and oxaliplatin with low molecular weight proteins [162] are examples of the potential of HPLC ICP MS, ESI MS, MALDI MS, and tandem MS techniques in such studies. Interaction of the drugs with sulfur-containing ligands (methionine and cysteine) can result in the generation of adducts of higher toxicity than the parent compounds.…”

Mass spectrometric quantification of the binding ratio of metal‐based anticancer complexes with protein thiols

“…Several methods for characterizing the metal–protein binding site have been set up, such as X‐ray crystallography, NMR spectroscopy and mass spectrometry (MS) . Moreover, a combination of nanoelectrospray MS and high‐performance liquid chromatography (HPLC)–inductively coupled plasma MS was applied to examine the interaction of a metal‐based anticancer drug with hemoglobin, and its therapeutic effects in the blood of cancer patients was also explored . However, a reliable method for evaluating the metal‐to‐thiol binding ratio which can be directly associated with the actual influence of a metal complex is still missing.…”

“…[22][23][24][25][26][27][28][29][30][31][32][33][34] Moreover, a combination of nanoelectrospray MS and high-performance liquid chromatography (HPLC)-inductively coupled plasma MS was applied to examine the interaction of a metalbased anticancer drug with hemoglobin, and its therapeutic effects in the blood of cancer patients was also explored. 35,36 However, a reliable method for evaluating the metal-to-thiol binding ratio which can be directly associated with the actual influence of a metal complex is still missing. Therefore, a simple and accurate way to measure the ratio of each metal-thiol binding is in great demand.…”