ABSTRACT
Multicellular tumor spheroids (MCTS) can simulate the structure and metabolic characteristics of tumors in vivo, which is of great significance to study the metabolic phenotype of tumor cells and the mechanism of drug intervention. In this study, esophageal cancer MCTS were constructed, and MCTS frozen sections were prepared after treated with different formulations of paclitaxel (PTX) including common PTX injection, PTX liposome and albumin bound PTX. MCTS mass spectrometry imaging analysis method was established by using air flow assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI). The visualization of the permeation and enrichment process of PTX in MCTs after PTX treatment was realized, and the spatially resolved metabolomics of PTX injection group was studied. The results showed that the permeation and enrichment behavior of PTX in MCTs model were related to the formulations. The changes of endogenous metabolites in MCTs of esophageal cancer after treated with PTX injection had temporal and spatial characteristics. The metabolic changes of MCTS during the initial 0-4 hours were dominated by the down-regulation of middle-high polarity metabolites and some lipids in the central region of MCTS, while the metabolic changes of MCTS during 8-72 hours were mainly up-regulated by lipid metabolites in the peripheral region of MCTS. The combination of in vivo tumor-associated MCTs model with label free, highly sensitive and high coverage mass spectrometry imaging technology provided a new method and strategy for the study of pharmacometabolomics.
ABSTRACT
PURPOSE: To establish new in vitro model systems that better reflect in vivo condition, multicellular tumor spheroids(MTS) and raft culture were developed using cell lines of squamous cell carcinoma(SCCHN) of the head and neck. In these 3-dimensional systems, the expression of cell surface molecules which are important for modulation of physiology of tumor cells were studied with or without the treatment of interferon(IFN)-gamma. MATERIALS AND METHODS: Four SCCHN cell lines were used for MTS and raft culture. The effects of interferon-gamma on SCCHN cells were examined by immunohistochemistry. RESULTS: All cell lines formed MTS, but only Tu-138 showed a good stratification at the air-liquid interface in the raft culture system. Immunohistochemical studies of MTS using monoclonal antibodies revealed a strong staining for MHC class I, no staining for MHC-DR, a weak patch expression of ICAM-1 and a central strong staining for integrin a 6. Staining patterns were similar for the raft cultures except integrin a 6(intense full-thickness positivity). In both systems, IFN-gamma enhanced the expression of MHC-DR and ICAM-1. No significant change was found in the expression of MHC class I and integrin a 6. CONCLUSIONS: MTS and raft culture system were established successfully from the SCCHN cell lines. IFN-gamma can modulate the surface molecules of tumor cells in the 3-dimensional culture systems.