Mechanism of action of trabectedin in desmoplastic small round cell tumor cells

Abstract

BackgroundDesmoplastic small round cell tumor (DSRCT) is a rare and highly aggressive disease, that can be described as a member of the family of small round blue cell tumors. The molecular diagnostic marker is the t(11;22)(p13;q12) translocation, which creates an aberrant transcription factor, EWS-WT1, that underlies the oncogenesis of DSRCT. Current treatments are not very effective so new active drugs are needed. Trabectedin, now used as a single agent for the treatment of soft tissue sarcoma, was reported to be active in some pre-treated DSRCT patients. Using JN-DSRCT-1, a cell line derived from DSRCT expressing the EWS-WT1 fusion protein, we investigated the ability of trabectedin to modify the function of the chimeric protein, as in other sarcomas expressing fusion proteins. After detailed characterization of the EWS-WT1 transcripts structure, we investigated the mode of action of trabectedin, looking at the expression and function of the oncogenic chimera.MethodsWe characterized JN-DSRCT-1 cells using cellular approaches (FISH, Clonogenicity assay) and molecular approaches (Sanger sequencing, ChIP, GEP).ResultsJN-DSRCT-1 cells were sensitive to trabectedin at nanomolar concentrations. The cell line expresses different variants of EWS-WT1, some already identified in patients. EWS-WT1 mRNA expression was affected by trabectedin and chimeric protein binding on its target gene promoters was reduced. Expression profiling indicated that trabectedin affects the expression of genes involved in cell proliferation and apoptosis.ConclusionsThe JN-DSRCT-1 cell line, in vitro, is sensitive to trabectedin: after drug exposure, EWS-WT1 chimera expression decreases as well as binding on its target promoters. Probably the heterogeneity of chimera transcripts is an obstacle to precisely defining the molecular mode of action of drugs, calling for further cellular models of DSRCT, possibly growing in vivo too, to mimic the biological complexity of this disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-017-3091-1) contains supplementary material, which is available to authorized users.

Current Approaches for Personalized Therapy of Soft Tissue Sarcomas

“…Trabectedin appears to bind directly with the chimeric protein and to impair transactivating activity of FUS-CHOP [37]. Similar results were obtained for trabectedin and EWS-WTI1-positive desmoplastic small round cell tumor [38], myxoid liposarcoma with EWS-DDIT3 [39], and Ewing's sarcoma with EWS-FLI1 translocation [40].…”

“…In vitro/in vivo studies [38] Inhibition of EWS-WT1 downstream target IGF1R with monoclonal antibody ganitumab Phase II clinical trial completed [42] Inhibition of EWS-WT1 downstream targets (mTOR, Notch, PDGFRB) with known approved inhibitors Phases I-II are ongoing or completed without significantly improvement of therapy outcomes [90] Endometrial stromal sarcoma, low grade t(7; 17) (p15; q21) JAZF1-JJAZ1 (aberrant transcription)…”

Trabectedin arrests a doxorubicin-resistant PDGFRA-activated liposarcoma patient-derived orthotopic xenograft (PDOX) nude mouse model

“…TRAB has been demonstrated as a therapeutic option in STS [ 56 , 57 , 80 – 86 ], recurrent ovarian cancer [ 87 ], metastatic breast cancer [ 88 ], solitary fibrous tumor (SFT)-PDXs [ 89 ], desmoplastic small round cell tumor [ 90 ], juvenile myelomonocytic leukaemia and chronic myelomonocytic leukaemia [ 91 ]. Recently, we reported that TRAB is efficacious on an osteosarcoma cisplatinum-resistant lung metastasis [ 67 ], a BRAF-V600E mutated melanoma [ 30 , 32 ] and a gemcitabine (GEM)-resistant pancreatic cancer [ 25 ].…”

Targeting Transcription Factors for Cancer Treatment

“…More recently, ET743 also alters DNA binding of another fused transcription factor protein: EWS-WT1 that originates from t(11;22)(p13;q12) and is responsible for desmoplastic small round cell tumors. Indeed, EWS-WT1 interaction with EGFR promoter is reduced upon ET743 treatment in JN-DSRCT-1 cells as evidenced using ChIP experiments [ 268 ].…”