Characterization of a new trabectedin-resistant myxoid liposarcoma cell line that shows collateral sensitivity to methylating agents

• Published in: International journal of cancer 2012-07, Vol.131 (1), p.59-69
• Main Authors: Uboldi, S., Bernasconi, S., Romano, M., Marchini, S., Fuso Nerini, I., Damia, G., Ganzinelli, M., Marangon, E., Sala, F., Clivio, L., Chiorino, G., Giandomenico, S. Di, Rocchi, M., Capozzi, O., Margison, G.P., Watson, A.J., Caccuri, A.M., Pastore, A., Fossati, A., Mantovani, R., Grosso, F., Tercero, J.C., Erba, E., D'Incalci, M.
• Format: Article
• Language: English
• Subjects: Antineoplastic Agents, Alkylating - pharmacology; Antitumor agents; Apoptosis; Biological and medical sciences; C-Reactive Protein - genetics; Cancer; CCAAT-Enhancer-Binding Protein-alpha - genetics; CCAAT-Enhancer-Binding Protein-beta - genetics; Cell fusion; Cell Line, Tumor; Cell lines; Cellular stress response; Chromatin; Collateral; Complementation; Dacarbazine - analogs & derivatives; Dacarbazine - pharmacology; Deoxyribonucleic acid; Dermatology; Dioxoles - pharmacology; Disease resistance; DNA; DNA Methylation; DNA methyltransferase; DNA Modification Methylases - deficiency; DNA Modification Methylases - genetics; DNA Modification Methylases - metabolism; DNA Repair; DNA Repair Enzymes - deficiency; DNA Repair Enzymes - genetics; DNA Repair Enzymes - metabolism; Drug Resistance, Neoplasm; Fibronectins - genetics; FUS gene; FUS-CHOP; Fusion protein; Gene fusion; Genes; Humans; Immunoprecipitation; Liposarcoma, Myxoid - drug therapy; Liposarcoma, Myxoid - genetics; Liposarcoma, Myxoid - metabolism; Liposarcoma, Myxoid - pathology; Medical research; Medical sciences; Methylguanine; Mutation; myxoid liposarcoma; Nucleotide excision repair; O6-methylguanine-DNA methyltransferase; Oncogene Proteins, Fusion - genetics; Oncogene Proteins, Fusion - metabolism; Promoter Regions, Genetic; Promoters; resistance; RNA-Binding Protein FUS - genetics; RNA-Binding Protein FUS - metabolism; Serum Amyloid P-Component - genetics; Signal Transduction; Temozolomide; Tetrahydroisoquinolines - pharmacology; trabectedin; Transcription Factor CHOP - genetics; Transcription Factor CHOP - metabolism; Tumor Suppressor Proteins - deficiency; Tumor Suppressor Proteins - genetics; Tumor Suppressor Proteins - metabolism; Tumors; Tumors of the skin and soft tissue. Premalignant lesions; Ultraviolet Rays
• ISSN: 0020-7136; 1097-0215
• DOI: 10.1002/ijc.26340

Myxoid Liposarcomas (MLS), characterized by the expression of FUS‐CHOP fusion gene are clinically very sensitive to the DNA binding antitumor agent, trabectedin. However, resistance eventually occurs, preventing disease eradication. To investigate the mechanisms of resistance, a trabectedin resistant cell line, 402‐91/ET, was developed. The resistance to trabectedin was not related to the expression of MDR related proteins, uptake/efflux of trabectedin or GSH levels that were similar in parental and resistant cells. The 402‐91/ET cells were hypersensitive to UV light because of a nucleotide excision repair defect: XPG complementation decreased sensitivity to UV rays, but only partially to trabectedin. 402‐91/ET cells showed collateral sensitivity to temozolomide due to the lack of O6‐methylguanine‐DNA‐methyltransferase (MGMT) activity, related to the hypermethylation of MGMT promoter. In 402‐91 cells chromatin immunoprecipitation (ChIP) assays showed that FUS‐CHOP was bound to the PTX3 and FN1 gene promoters, as previously described, and trabectedin caused FUS‐CHOP detachment from DNA. Here we report that, in contrast, in 402‐91/ET cells, FUS‐CHOP was not bound to these promoters. Differences in the modulation of transcription of genes involved in different pathways including signal transduction, apoptosis and stress response between the two cell lines were found. Trabectedin activates the transcription of genes involved in the adipogenic‐program such as c/EBPα and β, in 402‐91 but not in 402‐91/ET cell lines. The collateral sensitivity of 402‐91/ET to temozolomide provides the rationale to investigate the potential use of methylating agents in MLS patients resistant to trabectedin.