Search

[Background] Solitary fibrous tumour (SFT) is a rare mesenchymal malignancy that lacks robust prognostic and predictive biomarkers. Interferon-stimulated gene 15 (ISG15) is a ubiquitin-like modifier, associated with tumour progression, and with poor survival of SFT patients, as previous published by our group. Here, we describe the role of ISG15 in the biology of this rare tumour., [Methods] ISG15 expression was assessed by immunohistochemistry in tissue microarrays from SFT patients and tested for correlation with progression-free survival and overall survival (OS). The effects of ISG15 knockdown or induction were investigated for cancer stem cell (CSC) characteristics and for drug sensitivity in unique in vitro models of SFT., [Results] The prognostic value of ISG15 for OS was validated at protein level in malignant SFT patients, prospectively treated with pazopanib and enrolled in GEIS-32 trial. In SFT in vitro models, ISG15 knockdown lead to a decrease in the expression of CSC-related genes, including SOX2, NANOG, ALDH1A1, ABCB1 and ABCC1. Likewise, ISG15 downregulation decreased the clonogenic/ tumoursphere-forming ability of SFT cells, while enhancing apoptotic cell death after doxorubicin, pazopanib or trabectedin treatment in 3D cell cultures. The regulation of CSC-related genes by ISG15 was confirmed after inducing its expression with interferon-β1; ISG15 induction upregulated 1.28- to 451-fold the expression of CSC-associated genes., [Conclusions] ISG15 is a prognostic factor in malignant SFT, regulating the expression of CSC-related genes and CSCs maintenance. Our results suggest that ISG15 could be a novel therapeutic target in SFT, which could improve the efficacy of the currently available treatments., The project was partially funded by the Instituto de Salud Carlos III (ISCIII)–Fondo Europeo de Desarrollo Regional (FEDER), project reference PI18/01728. The project was also funded by SELNET project. SELNET has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 825806. DSM. is the recipient of a Sara Borrell postdoctoral fellowship funded by the National Institute of Health Carlos III (ISCIII) (CD20/00155). JLMH is the recipient of a PFIS predoctoral fellowship funded by the National Institute of Health Carlos III (ISCIII) (FI19/00184).

Although the overall survival of advanced soft-tissue sarcoma (STS) patients has increased in recent years, the median progression-free survival is lower than 5 months, meaning that there is an unmet need in this population. Among second-line treatments for advanced STS, eribulin is an anti-microtubule agent that has been approved for liposarcoma. Here, we tested the combination of eribulin with gemcitabine in preclinical models of L-sarcoma. The effect in cell viability was measured by MTS and clonogenic assay. Cell cycle profiling was studied by flow cytometry, while apoptosis was measured by flow cytometry and Western blotting. The activity of eribulin plus gemcitabine was evaluated in in vivo patient-derived xenograft (PDX) models. In L-sarcoma cell lines, eribulin plus gemcitabine showed to be synergistic, increasing the number of hypodiploid events (increased subG1 population) and the accumulation of DNA damage. In in vivo PDX models of L-sarcomas, eribulin combined with gemcitabine was a viable scheme, delaying tumour growth after one cycle of treatment, being more effective in leiomyosarcoma. The combination of eribulin and gemcitabine was synergistic in L-sarcoma cultures and it showed to be active in in vivo studies. This combination deserves further exploration in the clinical context., Eribulin and funding was kindly provided by Eisai. The authors would also like to thank the SELNET project. SELNET has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 825806. J. Martin-Broto, D.S. Moura and N. Hindi would like to thank the International Accelerator Award funded by Cancer Research UK [C56167/A29363]. DSM is the recipient of a Sara Borrell postdoctoral fellowship funded by the National Institute of Health Carlos III (ISCIII) (CD20/00155). JLMH is the recipient of a PFIS predoctoral fellowship funded by the National Institute of Health Carlos III (ISCIII) (FI19/00184). The authors thank HUVR-IBiS Biobank (Andalusian Public Health System Biobank and ISCIII-Red de Biobancos PT17/0015/0041) for the processing and staining of PDX samples used in this study.

Rhabdomyosarcoma (RMS) in adults is a rare and aggressive disease, which lacks standard therapies for relapsed or advanced disease. This retrospective study aimed to describe the activity of BOMP-EPI (bleomycin, vincristine, methotrexate and cisplatin alternating with etoposide, cisplatin and ifosfamide), an alternative platinum-based regimen, in adult patients with relapsed/metastatic RMS. In the study, 10 patients with RMS with a median age at diagnosis of 20.8 years and a female/male distribution of 6/4 received a mean of 2.5 cycles of BOMP-EPI. The best RECIST response was a complete response in 1/10 (10%) patients, a partial response in 5/10 (50%), stable disease in 3/10 (30%) and progression in 1/10 (10%). With a median follow-up in the alive patients from the start of therapy of 30.5 months (15.7–258), all patients progressed with a median progression-free survival of 8.47 months (95% CI 8.1–8.8), and 7/10 patients died with a median overall survival of 24.7 months (95% CI 13.7–35.6). BOMP-EPI was an active chemotherapy regimen in adults with pediatric-type metastatic RMS, with outcomes in terms of survival that seem superior to what was expected for this poor-prognosis population. Low HMGB1 expression level was identified as a predictive factor of better response to this treatment.

MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate gene expression at the post-transcriptional level, and they have been described as being associated with tumor prognosis. Here, miRNA profiling was planned to explore new molecular prognostic biomarkers in localized intestinal high-risk GIST. Paraffin tumor blocks of 14 and 86 patients were used in the discovery and expansion sets, respectively. GeneChip miRNA v3.0 was employed to identify the miRNAs differentially expressed between relapsed and non-relapsed patient samples, which were validated in the expansion set, by qRT-PCR. RT2 Profiler PCR Array was used for the screening of let-7e targets. Expression levels were correlated with relapse-free survival and overall survival. In the discovery set, 39 miRNAs were significantly deregulated, let-7e and miR-550 being the most underexpressed and overexpressed miRNAs in the relapsed group, respectively. In the expansion set, the underexpression of let-7e or the overexpression of 4 of its target genes (ACVR1B, CASP3, COL3A1, and COL5A2) were statistically associated with worse relapse-free survival. The expression of let-7e and 4 of its target genes are potential prognostic biomarkers in high-risk localized intestinal GIST. The expression of these genes is a potential molecular tool useful for a more accurate prognosis in this subset of GIST patients.

Simple Summary For intestinal localized high-risk gastrointestinal stromal tumors (GIST) patients’ new molecular biomarkers are urgently needed for a more accurate prognosis. In our study, miRNA profiling analyses was planned to explore new molecular biomarkers with potential prognostic role in this clinical context. Our data, revealed that 39 microRNAs (miRNAs) were significantly deregulated when comparing patients with disease relapsed versus non-relapsed cases. The underexpression of a specific miRNA let-7e and the overexpression of 4 of its target genes (ACVR1B, CASP3, COL3A1 and COL5A2) correlated significantly with worse relapse-free survival. Overall, our results suggest that miRNA profiling is a potential molecular tool useful for a more accurate prognosis for intestinal localized high-risk GIST patients. Abstract MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate gene expression at the post-transcriptional level, and they have been described as being associated with tumor prognosis. Here, miRNA profiling was planned to explore new molecular prognostic biomarkers in localized intestinal high-risk GIST. Paraffin tumor blocks of 14 and 86 patients were used in the discovery and expansion sets, respectively. GeneChip miRNA v3.0 was employed to identify the miRNAs differentially expressed between relapsed and non-relapsed patient samples, which were validated in the expansion set, by qRT-PCR. RT2 Profiler PCR Array was used for the screening of let-7e targets. Expression levels were correlated with relapse-free survival and overall survival. In the discovery set, 39 miRNAs were significantly deregulated, let-7e and miR-550 being the most underexpressed and overexpressed miRNAs in the relapsed group, respectively. In the expansion set, the underexpression of let-7e or the overexpression of 4 of its target genes (ACVR1B, CASP3, COL3A1, and COL5A2) were statistically associated with worse relapse-free survival. The expression of let-7e and 4 of its target genes are potential prognostic biomarkers in high-risk localized intestinal GIST. The expression of these genes is a potential molecular tool useful for a more accurate prognosis in this subset of GIST patients.

A translational study was designed to analyze the expression of nucleotide excision repair (NER) and homologous recombination (HR) genes as potential predictive biomarkers for trabectedin in soft-tissue sarcoma (STS). This study is part of a randomized phase II trial comparing trabectedin plus doxorubicin versus doxorubicin in advanced STS. Gene expression levels were evaluated by qRT-PCR, while CUL4A protein levels were quantified by immunohistochemistry. Expression levels were correlated with patients&rsquo, progression-free survival (PFS) and overall survival (OS). Gene expression was also evaluated in cell lines and correlated with trabectedin sensitivity. In doxorubicin arm and in the whole series, which includes samples from both arms, no significant differences in terms of PFS were observed amongst the analyzed genes. In the group treated with trabectedin plus doxorubicin, the median of PFS was significantly longer in cases with CUL4A, ERCC1, or ERCC5 overexpression, while BRCA1 expression did not correlated with PFS. Gene expression had no prognostic influence in OS. CUL4A protein levels correlated with worse PFS in doxorubicin arm and in the whole series. In cell lines, only overexpression of ERCC1 was significantly correlated with trabectedin sensitivity. In conclusion, CUL4A, ERCC5, and mainly ERCC1 acted as predictive factors for trabectedin efficacy in advanced STS.

The classical activity of telomerase (TERT) is to maintain telomere homeostasis, ensuring chromosome stability and cellular proliferation. However, increasing evidences of telomere-independent human TERT functions have been lastly obtained. We report here that TERT directly binds to the TCF binding elements (TBE) located upstream the oncomiRMIR500Ainducing its expression and promoting cancer invasiveness. This function is independent of telomerase activity, since catalytic inactive TERT also inducesMIR500Aexpression and telomerase inhibitors directed against TERT, but not to its RNA componentTERC, inhibit telomerase-inducedMIR500Aexpression and cancer invasiveness. Mechanistically, telomerase-inducedMIR500Adown-regulates key genes of the Hedgehog signaling pathway, namely patched 1 (PTCH1), Gli family zinc finger 3 (GLI3) and cullin 3 (CUL3), increasing tumor invasiveness. Our results show a crucial role of the TERT/MIR500A/Hedgehog axis is tumor aggressiveness, pointing out to the relevance of inhibiting the extracurricular functions of telomerase to fight cancer.

11546 Background: Despite several second-line options are accessible for the treatment of advanced STS, there is a lack of predictive biomarkers available to support the rational selection of these drugs. Trabectedin specifically targets mononuclear cell lineage (macrophages and monocytes) that ultimately could inhibit tumor angiogenesis. Moreover, trabectedin seems to induce the expression of immune-checkpoint proteins (e.g. PD-L1); however, the predictive value of these factors remains unknown. We present the analyses of immune-checkpoint genes ( CD274, CD86, CTLA4, HAVCR2, LAG3 and PDCD1) and CD163, CD4, CD68 and CD8A expression as potential predictive factors of response to trabectedin in a subset of STS patients of the GEIS registry. Methods: Selection criteria included patients with STS, pretreated with at least 2 lines in the advanced setting (one line being trabectedin), with paraffin block available and ethic committee’s approval. Direct transcriptomics was performed using HTG Molecular Oncology Biomarker Pathway panel (HTG Molecular Diagnostics, Inc.; Tucson, AZ, USA), following manufacturers’ instructions. Data analyses were performed taking into account the median Log2 of expression of each gene and by correlating it with progression-free survival (PFS) for trabectedin, and overall survival measured from the starting date of trabectedin treatment (OS). Results: Among 387 registered patients, fitting with the inclusions criteria, 139 cases were used for gene expression analyses, as the discovery set. Patients had median age of 52 years, 54% were females and had a median follow-up from diagnosis of 44 months. High expression of CD274 (PD-L1) was significantly associated with better PFS of trabectedin (5.4 vs. 3.0 months; p= 0.006). Similar results were obtained with high expression of CTLA4 and LAG3: 6.0 vs 3.1 months; p = 0.005 and 5.4 vs 2.7 months; p = 0.042, respectively. Expression of CTLA4 and LAG3 showed no significant impact in OS; whereas CD274 high expression showed a trend towards better OS (17.9 vs 10.2 months; p = 0.077). Also, no significant correlation was achieved for CD163, CD4, CD68, CD8A, CD86 and HAVCR2; PDCD1 (PD-1) showed a trend towards better PFS of trabectedin, p = 0.114. Conclusions: The expression of selected immune-checkpoint genes exhibited a potential predictive value for trabectedin in advanced STS. Validation studies (at the transcriptional and protein level) are currently ongoing to confirm their potential predictive role.