Accelerator mass spectrometry allows for cellular quantification of doxorubicin at femtomolar concentrations

Abstract

Accelerator mass spectrometry (AMS) is a highly sensitive analytical methodology used to quantify the content of radioisotopes, such as 14 C, in a sample. The primary goals of this work were to demonstrate the utility of AMS in determining cellular [ 14 C]doxorubicin (DOX) concentrations and to develop a sensitive assay that is superior to high performance liquid chromatography (HPLC) for the quantification of DOX at the tumor level. In order to validate the superior sensitivity of AMS versus HPLC with fluorescence detection, we performed three studies comparing the cellular accumulation of DOX: one in vitro cell line study, and two in vivo xenograft mouse studies. Using AMS, we quantified cellular DOX content up to 4 hours following in vitro exposure at concentrations ranging from 0.2 pg/ml (345 fM) to 2 Fg/ml (3.45The results of this study show that, compared to standard fluorescence-based HPLC, the AMS method was over five orders of magnitude more sensitive. Two in vivo studies compared the sensitivity of AMS to HPLC using a nude mouse xenograft model in which breast cancer cells were implanted subcutaneously. After sufficiently large tumors formed, DOX was administered intravenously at two dose levels. Additionally, we tested the AMS method in a nude mouse xenograft model of multidrug resistance (MDR) in which each mouse was implanted with both wild type and MDR+ cells on opposite flanks. The results of the second and third studies showed that DOX concentrations were significantly higher in the wild type tumors compared to the MDR+ tumors, consistent with the MDR model. The extreme sensitivity of AMS should facilitate similar studies in humans to establish target site drug delivery and to potentially determine the optimal treatment dose and regimen.3

Detection of Adriamycin–DNA adducts by accelerator mass spectrometry at clinically relevant Adriamycin concentrations

“…AMS has exhibited over five orders of magnitude higher sensitivity for detection of radiocarbon-labelled Adriamycin compared to other routinely-used assays such as HPLC (48). DNA adduct studies with many DNA binders have also demonstrated linear dose responses using AMS detection (31).…”

"MS-Patch-Clamp" or the Possibility of Mass Spectrometry Hybridization with Patch-Clamp Setups for Single Cell Metabolomics and Channelomics

“…FTICR может provide a detection limit of approximately 30 zmol (≈ 18 000 molecules) for proteins with molecular weights ranging from 8 to 20 kDa [64]. To date the detection limit for accelerator massspectrometry in different analytical protocols is not as low as femtomolar [65,66] and attomolar [67,68], but even subattomolar [69] and zeptomolar [70][71][72] concentrations, corresponding to the sensitivity at the atomic level and satisfying the trend to the «accelerator mass spectrometryisotope measurements at the atomic level» [72]. Thus, the accuracy of MS-patch-clamp analysis can be significantly improved with the implementation of «accelerator MSpatch-clamp» concept.…”

Accelerator Mass Spectrometry-Enabled Studies: Current Status and Future Prospects

“…Researchers used AMS to quantify total cellular 14 C-anthracycline concentrations, following administration of doxorubicin, an anthracycline chemotherapeutic agent [55]. Two different mouse models were used:…”