Unique features of the mode of action of ET-743

This paper describes the current knowledge of the primary mode of action of a natural product, ecteinascidin 743 (ET-743), derived from the marine tunicate Ecteinascidia turbinata. ET-743 was initially selected for preclinical development because of its potent antitumor activity observed against several human solid tumor types. In vitro, the drug is cytotoxic in the nanomolar range, and in the case of some very sensitive cell lines, in the picomolar range. The large potency differences observed among several solid tumor types indicate that this compound possesses some tumor selectivity, but the molecular basis of these differential effects remains to be elucidated. The present studies were undertaken to evaluate the mechanism of action of ET-743 in this context. The available information on ET-743 binding to DNA and its effects on transcriptional regulation point to a unique behavior of this drug, as it independently affects specific gene transcription in a promoter-dependent way. In addition, ET-743 shows a peculiar pattern of selectivity in cells with different defects in their DNA-repair pathways. These results highlight a unique property of ET-743, possibly explaining why it possesses antitumor activity against tumors that are refractory to standard anticancer drugs, all of which certainly act by mechanisms that are different from that of ET-743

Clinical, biochemical and molecular characterization of prosaposin deficiency

Prosaposin (PSAP) deficiency is an ultra-rare, fatal infantile lysosomal storage disorder (LSD) caused by variants in the PSAP gene, with 7 subjects reported so far. Here, we provide the clinical, biochemical and molecular characterization of two additional PSAP deficiency cases. Lysoplex, a targeted resequencing approach was utilized to identify the variant in the first patient, while quantification of plasma lysosphingolipids (lysoSLs), assessed by liquid chromatography mass spectrometry (LC-MS/MS) and brain magnetic resonance imaging (MRI), followed by Sanger sequencing allowed to attain diagnosis in the second case. Functional studies were carried out on patients' fibroblast lines to explore the functional impact of variants. The two patients were homozygous for two different truncating PSAP mutations (c.895G>T, p.Glu299*; c.834_835delGA, p.Glu278Aspfs*27). Both variants led to a complete lack of processed transcript. LC-MS/MS and brain MRI analyses consistently provided a distinctive profile in the two children. Quantification of specific plasma lysoSLs revealed elevated levels of globotriaosylsphingosine (lysoGb3) and glucosylsphingosine (GlSph), and accumulation of autophagosomes, due to a decreased autophagic flux, was observed. This report documents the successfully use of plasma lysoSLs profiling in the PSAP deficiency diagnosis, as a reliable and informative tool to obtain a preliminary information in infantile cases with complex traits displaying severe neurological signs and visceral involvement.Prosaposin (PSAP) deficiency is an ultra-rare, fatal infantile lysosomal storage disorder (LSD) caused by variants in the PSAP gene, with seven subjects reported so far. Here, we provide the clinical, biochemical and molecular characterization of two additional PSAP deficiency cases. Lysoplex, a targeted resequencing approach was utilized to identify the variant in the first patient, while quantification of plasma lysosphingolipids (lysoSLs), assessed by liquid chromatography mass spectrometry (LC-MS/MS) and brain magnetic resonance imaging (MRI), followed by Sanger sequencing allowed to attain diagnosis in the second case. Functional studies were carried out on patients' fibroblast lines to explore the functional impact of variants. The two patients were homozygous for two different truncating PSAP mutations (c.895G>T, p.Glu299*; c.834_835delGA, p.Glu278Aspfs*27). Both variants led to a complete lack of processed transcript. LC-MS/MS and brain MRI analyses consistently provided a distinctive profile in the two children. Quantification of specific plasma lysoSLs revealed elevated levels of globotriaosylsphingosine (LysoGb3) and glucosylsphingosine (GlSph), and accumulation of autophagosomes, due to a decreased autophagic flux, was observed. This report documents the successful use of plasma lysoSLs profiling in the PSAP deficiency diagnosis, as a reliable and informative tool to obtain a preliminary information in infantile cases with complex traits displaying severe neurological signs and visceral involvement

Conservative management of early-stage epithelial ovarian cancer: results of a large retrospective series

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IGFBP-4 tumor and serum levels are increased across all stages of epithelial ovarian cancer

<p>Abstract</p> <p>Background</p> <p>We sought to identify candidate serum biomarkers for the detection and surveillance of EOC. Based on RNA-Seq transcriptome analysis of patient-derived tumors, highly expressed secreted proteins were identified using a bioinformatic approach.</p> <p>Methods</p> <p>RNA-Seq was used to quantify papillary serous ovarian cancer transcriptomes. Paired end sequencing of 22 flash frozen tumors was performed. Sequence alignments were processed with the program ELAND, expression levels with ERANGE and then bioinformatically screened for secreted protein signatures. Serum samples from women with benign and malignant pelvic masses and serial samples from women during chemotherapy regimens were measured for IGFBP-4 by ELISA. Student's t Test, ANOVA, and ROC curves were used for statistical analysis.</p> <p>Results</p> <p>Insulin-like growth factor binding protein (IGFBP-4) was consistently present in the top 7.5% of all expressed genes in all tumor samples. We then screened serum samples to determine if increased tumor expression correlated with serum expression. In an initial discovery set of 21 samples, IGFBP-4 levels were found to be elevated in patients, including those with early stage disease and normal CA125 levels. In a larger and independent validation set (82 controls, 78 cases), IGFBP-4 levels were significantly increased (p < 5 × 10^-5). IGFBP-4 levels were ~3× greater in women with malignant pelvic masses compared to women with benign masses. ROC sensitivity was 73% at 93% specificity (AUC 0.816). In women receiving chemotherapy, average IGFBP-4 levels were below the ROC-determined threshold and lower in NED patients compared to AWD patients.</p> <p>Conclusions</p> <p>This study, the first to our knowledge to use RNA-Seq for biomarker discovery, identified IGFBP-4 as overexpressed in ovarian cancer patients. Beyond this, these studies identified two additional intriguing findings. First, IGFBP-4 can be elevated in early stage disease without elevated CA125. Second, IGFBP-4 levels are significantly elevated with malignant versus benign disease. These findings provide the rationale for future validation studies.</p

The disruption of the CCDC6 - PP4 axis induces a BRCAness like phenotype and sensitivity to PARP inhibitors in high-grade serous ovarian carcinoma

Treatment with PARP inhibitors (PARPi) is primarily effective against high-grade serous ovarian cancers (HGSOC) with BRCA1/2 mutations or other deficiencies in homologous recombination (HR) repair mechanisms. However, resistance to PARPi frequently develops, mostly as a result of BRCA1/2 reversion mutations. The tumour suppressor CCDC6 is involved in HR repair by regulating the PP4c phosphatase activity on γH2AX. In this work, we reported that in ovarian cancer cells, a physical or functional loss of CCDC6 results synthetic lethal with the PARP-inhibitors drugs, by affecting the HR repair. We also unravelled a role for CCDC6 as predictive marker of PARPi sensitivity in ovarian cancer, and the impact of CCDC6 downregulation in overcoming PARPi resistance in these tumours

OC152: Prevalence of cancer and optimal cut‐off levels for mathematical models to distinguish between benign and malignant adnexal masses

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ajcr0000112d

Abstract: Epithelial ovarian cancer is a malignancy with high rate of death due to an advanced disease at diagnosis and frequent relapse after chemotherapy. Nowadays, there is a lack of knowledge for clear risk factors and predictive and/or prognostic genetic markers although genomic alterations such as mutations in p53, PTEN, BRCA1/BRCA2, HER2, KRAS and PI3K genes have been associated to this pathology. A genomic variant in the 3&apos; untraslated region of cancer related gene KRAS, is able to disrupt the let-7 miRNA binding site. The SNP, commonly named KRAS-LCS6, determines the substitution of the more abundant T-allele to a G-allele which was observed to increase the KRAS expression and in turn to activate the downstream pathway at higher levels if compared to the T-allele. In this study we assessed the role of the KRAS-LCS6 polymorphism (rs61764370) in 97 early (stages I and II) and 232 advanced (stages III and IV) ovarian cancer patients in order to associate this SNP to any physiopathological characteristic of the patients cohort, including progression free survival and overall survival, with a follow up data longer than ten years. Our data indicate that KRAS-LCS6 polymorphism is not relevant in ovarian cancer, in fact, in our cohort of patients, is not associated to any outcome or physiopathological characteristic

Application of RNA-Seq transcriptome analysis: CD151 is an Invasion/Migration target in all stages of epithelial ovarian cancer

<p>Abstract</p> <p>Background</p> <p>RNA-Seq allows a theoretically unbiased analysis of both genome-wide transcription levels and mutation status of a tumor. Using this technique we sought to identify novel candidate therapeutic targets expressed in epithelial ovarian cancer (EOC).</p> <p>Methods</p> <p>Specifically, we sought candidate invasion/migration targets based on expression levels across all tumors, novelty of expression in EOC, and known function. RNA-Seq analysis revealed the high expression of CD151, a transmembrane protein, across all stages of EOC. Expression was confirmed at both the mRNA and protein levels using RT-PCR and immunohistochemical staining, respectively.</p> <p>Results</p> <p>In both EOC tumors and normal ovarian surface epithelial cells we demonstrated CD151 to be localized to the membrane and cell-cell junctions in patient-derived and established EOC cell lines. We next evaluated its role in EOC dissemination using two ovarian cancer-derived cell lines with differential levels of CD151 expression. Targeted antibody-mediated and siRNA inhibition or loss of CD151 in SKOV3 and OVCAR5 cell lines effectively inhibited their migration and invasion.</p> <p>Conclusion</p> <p>Taken together, these findings provide the first proof-of-principle demonstration for a next generation sequencing approach to identifying candidate therapeutic targets and reveal CD151 to play a role in EOC dissemination.</p

Platinum sensitivity and DNA repair in a recently established panel of patient-derived ovarian carcinoma xenografts

A xenobank of patient-derived (PDX) ovarian tumor samples has been established consisting of tumors with different sensitivity to cisplatin (DDP), from very responsive to resistant. As the DNA repair pathway is an important driver in tumor response to DDP, we analyzed the mRNA expression of 20 genes involved in the nucleotide excision repair, fanconi anemia, homologous recombination, base excision repair, mismatch repair and translesion repair pathways and the methylation patterns of some of these genes. We also investigated the correlation with the response to platinum-based therapy. The mRNA levels of the selected genes were evaluated by Real Time-PCR (RT-PCR) with ad hoc validated primers and gene promoter methylation by pyrosequencing. All the DNA repair genes were variably expressed in all 42 PDX samples analyzed, with no particular histotype-specific pattern of expression. In high-grade serous/endometrioid PDXs, the CDK12 mRNA expression levels positively correlated with the expression of TP53BP1, PALB2, XPF and POLB. High-grade serous/endometrioid PDXs with TP53 mutations had significantly higher levels of POLQ, FANCD2, RAD51 and POLB than high-grade TP53 wild type PDXs. The mRNA levels of CDK12, PALB2 and XPF inversely associated with the in vivo DDP antitumor activity; higher CDK12 mRNA levels were associated with a higher recurrence rate in ovarian patients with low residual tumor. These data support the important role of CDK12 in the response to a platinum based therapy in ovarian patients