Endometrial cancer PDX-derived organoids (PDXOs) and PDXs with FGFR2c isoform expression are sensitive to FGFR inhibition

Endometrial cancer; Immunohistochemistry; Predictive markersCàncer d'endometri; Immunohistoquímica; Marcadors predictiusCáncer de endometrio; Inmunohistoquímica; Marcadores predictivosEndometrial cancer (EC) patients with metastatic/recurrent disease have limited treatment options and poor survival outcomes. Recently, we discovered the FGFR2c splice isoform is associated with poor prognosis in EC patients. Here we report the establishment of 16 EC patient-derived xenografts (PDX)-derived organoids (PDXOs) with or without FGFR2c expression. In vitro treatment of 5 EC PDXOs with BGJ398 showed significant cell death in 3 models with FGFR2c expression. PDXs with high/moderate FGFR2c expression showed significant tumour growth inhibition (TGI) following 21-day treatment with FGFR inhibitors (BGJ398 or pemigatinib) and significantly prolonged survival in 4/5 models. Pemigatinib + cisplatin combination therapy (n = 5) resulted in significant TGI and prolonged survival in one of two p53abn PDXs. All five models treated with cisplatin alone showed de novo resistance and no survival benefit. Seven-day treatment with BGJ398 revealed a significant reduction in angiogenesis and CD206 + M2 macrophages. These data collectively support the evaluation of FGFR inhibitors in a clinical trial

The 'Melanoma-enriched' microRNA miR-4731-5p acts as a tumour suppressor

We previously identified miR-4731-5p (miR-4731) as a melanoma-enriched microRNA following comparison of melanoma with other cell lines from solid malignancies. Additionally, miR-4731 has been found in serum from melanoma patients and expressed less abundantly in metastatic melanoma tissues from stage IV patients relative to stage III patients. As miR-4731 has no known function, we used biotin-labelled miRNA duplex pull-down to identify binding targets of miR-4731 in three melanoma cell lines (HT144, MM96L and MM253). Using the miRanda miRNA binding algorithm, all pulled-down transcripts common to the three cell lines (n=1092) had potential to be targets of miR-4731 and gene-set enrichment analysis of these (via STRING v9.1) highlighted significantly associated genes related to the ‘cell cycle’ pathway and the ‘melanosome’. Following miR-4731 overexpression, a selection (n=81) of pull-down transcripts underwent validation using a custom qRT-PCR array. These data revealed that miR-4731 regulates multiple genes associated with the cell cycle (e.g. CCNA2, ORC5L, and PCNA) and the melanosome (e.g. RAB7A, CTSD, and GNA13). Furthermore, members of the synovial sarcoma X breakpoint family (SSX) (melanoma growth promoters) were also down-regulated (e.g. SSX2, SSX4, and SSX4B) as a result of miR-4731 overexpression. Moreover, this down-regulation of mRNA expression resulted in ablation or reduction of SSX4 protein, which, in keeping with previous studies, resulted in loss of 2D colony formation. We therefore speculate that loss of miR-4731 expression in stage IV patient tumours supports melanoma growth by, in part; reducing its regulatory control of SSX expression levels

Complex structural rearrangements are present in high-grade dysplastic Barrett\u27s oesophagus samples

Background: Oesophageal adenocarcinoma (EAC) incidence is increasing and has a poor survival rate. Barrett’s oesophagus (BE) is a precursor condition that is associated with EAC and often occurs in conjunction with chronic gastro-oesophageal reflux, however many individuals diagnosed with BE never progress to cancer. An understanding of the genomic features of BE and EAC may help with the early identification of at-risk individuals. Methods: In this study, we assessed the genomic features of 16 BE samples using whole-genome sequencing. These included non-dysplastic samples collected at two time-points from two BE patients who had not progressed to EAC over several years. Seven other non-dysplastic samples and five dysplastic BE samples with high-grade dysplasia were also examined. We compared the genome profiles of these 16 BE samples with 22 EAC samples. Results: We observed that samples from the two non-progressor individuals had low numbers of somatic single nucleotide variants, indels and structural variation events compared to dysplastic and the remaining non-dysplastic BE. EAC had the highest level of somatic genomic variations. Mutational signature 17, which is common in EAC, was also present in non-dysplastic and dysplastic BE, but was not present in the non-progressors. Many dysplastic samples had mutations in genes previously reported in EAC, whereas only mutations in CDKN2A or in the fragile site genes appeared common in non-dysplastic samples. Rearrangement signatures were used to identify a signature associated with localised complex events such as chromothripsis and breakage fusion-bridge that are characteristic of EACs. Two dysplastic BE samples had a high contribution of this signature and contained evidence of localised rearrangements. Two other dysplastic samples also had regions of localised structural rearrangements. There was no evidence for complex events in non-dysplastic samples. Conclusions: The presence of complex localised rearrangements in dysplastic samples indicates a need for further investigations into the role such events play in the progression from BE to EAC

Cross-Platform Array Screening Identifies COL1A2, THBS1, TNFRSF10D and UCHL1 as Genes Frequently Silenced by Methylation in Melanoma

Epigenetic regulation of tumor suppressor genes (TSGs) has been shown to play a central role in melanomagenesis. By integrating gene expression and methylation array analysis we identified novel candidate genes frequently methylated in melanoma. We validated the methylation status of the most promising genes using highly sensitive Sequenom Epityper assays in a large panel of melanoma cell lines and resected melanomas, and compared the findings with those from cultured melanocytes. We found transcript levels of UCHL1, COL1A2, THBS1 and TNFRSF10D were inversely correlated with promoter methylation. For THBS1 and UCHL1 the effect of this methylation on expression was confirmed at the protein level. Identification of these candidate TSGs and future research designed to understand how their silencing is related to melanoma development will increase our understanding of the etiology of this cancer and may provide tools for its early diagnosis

Complex structural rearrangements are present in high-grade dysplastic Barrett’s oesophagus samples

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Abstract Background Oesophageal adenocarcinoma (EAC) incidence is increasing and has a poor survival rate. Barrett’s oesophagus (BE) is a precursor condition that is associated with EAC and often occurs in conjunction with chronic gastro-oesophageal reflux, however many individuals diagnosed with BE never progress to cancer. An understanding of the genomic features of BE and EAC may help with the early identification of at-risk individuals. Methods In this study, we assessed the genomic features of 16 BE samples using whole-genome sequencing. These included non-dysplastic samples collected at two time-points from two BE patients who had not progressed to EAC over several years. Seven other non-dysplastic samples and five dysplastic BE samples with high-grade dysplasia were also examined. We compared the genome profiles of these 16 BE samples with 22 EAC samples. Results We observed that samples from the two non-progressor individuals had low numbers of somatic single nucleotide variants, indels and structural variation events compared to dysplastic and the remaining non-dysplastic BE. EAC had the highest level of somatic genomic variations. Mutational signature 17, which is common in EAC, was also present in non-dysplastic and dysplastic BE, but was not present in the non-progressors. Many dysplastic samples had mutations in genes previously reported in EAC, whereas only mutations in CDKN2A or in the fragile site genes appeared common in non-dysplastic samples. Rearrangement signatures were used to identify a signature associated with localised complex events such as chromothripsis and breakage fusion-bridge that are characteristic of EACs. Two dysplastic BE samples had a high contribution of this signature and contained evidence of localised rearrangements. Two other dysplastic samples also had regions of localised structural rearrangements. There was no evidence for complex events in non-dysplastic samples. Conclusions The presence of complex localised rearrangements in dysplastic samples indicates a need for further investigations into the role such events play in the progression from BE to EAC

Gene expression array analysis to identify candidate tumor suppressor genes in melanoma

Melanoma is a complex multifactorial disease; therefore, a combination of various approaches is necessary to girt all aspects of its biology and identify the many different genes and factors involved in its etiology.Epigenetic regulation of tumor suppressor genes (TSGs) has been shown to play a central role in melanomagenesis. Here, we describe a new pipeline based on an integrative and comparative analysis of several array platform, post-demethylation treatment expression data, methylation array, and constitutive mRNA expression analysis to identify novel TSGs frequently methylated in melanoma

Complementation analyses suggest species-specific functions of the SNF5 homology domain

Inactivation on both alleles of the hSNF5/INI1 tumor suppressor gene which encodes a subunit of the human SWI/SNF chromatin remodelling complex occurs in most malignant rhabdoid tumors. No paralog of hSNF5/INI1 is identified in the human genome. In contrast, it has two homologs in the yeast Saccharomyces cerevisiae, SNF5 and SFH1 which encode core components of the ySWI/SNF and RSC complexes, respectively. The homology mainly concerns an approximately 200 amino acid region termed the SNF5 homology domain. We have tested the ability of the hSNF5/INI1-wild type gene product and of chimerical constructs in which the yeast SNF5 domains were replaced by that of the human protein, to complement yeast snf5 and sfh1 phenotypes. Neither growth deficiencies on different carbon sources of snf5 yeasts nor the lethality of the sfh1 phenotype could be rescued. This strongly suggests that the SNF5 homology domain presents species-specific functions

PI3K inhibitors synergize with FGFR inhibitors to enhance antitumor responses in FGFR2-mutant endometrial cancers

Improved therapeutic approaches are needed for the treatment of recurrent and metastatic endometrial cancer (EC). ECs display hyper-activation of the MAPK and PI3K pathways, the result of somatic aberrations in genes such as FGFR2, KRAS, PTEN, PIK3CA and PIK3R1. FGFR2, as well as the PI3K pathway, have emerged as potential therapeutic targets in EC. Activation of the PI3K pathway is seen in >90% of FGFR2mutant ECs. This study aimed to examine the efficacy of the pan-FGFR inhibitor BGJ398 with pan-PI3K inhibitors (GDC-0941, BKM120) and the p110α-selective inhibitor BYL719. We assessed synergy in three FGFR2mutant EC cell lines (AN3CA, JHUEM2 and MFE296) and the combination of BGJ398 and GDC-0941 or BYL719 showed strong synergy. A significant increase in cell death and decrease in long-term survival was seen when PI3K inhibitors were combined with BGJ398. Importantly, these effects were seen at low concentrations correlating to only partial inhibition of AKT. The combination of BGJ398 and GDC-0941 showed tumor regressions in vivo, whereas each drug alone only showed moderate tumor growth inhibition. BYL719 alone resulted in increased tumor growth of AN3CA xenografts, but in combination with BGJ398 resulted in tumor regression in both AN3CA and JHUEM2-derived xenografts. These data provide evidence that sub-therapeutic doses of PI3K inhibitors enhance the efficacy of anti-FGFR therapies and a combination therapy may represent a superior therapeutic treatment in FGFR2mutant EC patients

Targeting FGFR2c isoform, a novel therapeutic target with FGFR inhibitor in endometrial cancer

Purpose: Endometrial cancer (EC) is the most frequently diagnosed gynaecological cancer. The majority of women with EC are treated surgically and have a good outcome, however 25-30% of patients presenting with metastases or recurrent disease do not have effective therapies and have Method: BaseScope RNA ISH was used to detect FGFR2c expression in patient tumours, PDX models and PDXOs. PDXOs derived from three independent PDX tumours were established from each of five PDX models (3 showing high FGFR2c expression, 2 showing low/no FGFR2c expression). Each PDXO culture was treated with 300nM BGJ398 (pan-FGFRi) or DMSO for 72 h and assessed using a live-dead assay and confocal microscopy. PDXs from three models were engrafted subcutaneously into 8 weeks female NSG mice and when tumours reached 100-150mm3, mice were randomized (4 mice/arm) and treated with 30mg/Kg BGJ398 or vehicle daily for 21 days. Tumours were measured 3x/week and mice sacrificed when tumours reached 900mm3. Results and conclusion: FGFR2c expression was higher in PDXs representing the dMMR and p53wt subtype compared to p53mut subtype and similar expression levels were seen between patient tumours, PDXs and PDXOs. In vitro FGFRi with BGJ398 showed significant cell death occurred in PDXOs with high FGFR2c expression (pin vitro findings were validated in vivo using PDX68 carrying a FGFR2 C383R mutation and PDX52 and PDX59, both showing FGFR2 isoform switching. Significant tumour growth inhibition and a ~2-fold increase in survival was seen in all three models (PDX68, p<0.0001 and p<0.007; PDX52, p<0.02 and P<0.03; and PDX59 P<0.0001 and P<0.0006 respectively). In conclusion, our investigation revealed FGFRi (BGJ398) was effective in EC PDX models representing both mutational activation and isoform switching of FGFR2. As FGFR isoform switching occurs most commonly in the dMMR subtype where immune checkpoint inhibitors (ICIs) are approved, we propose the combination of ICIs and FGFRi may be more effective in women with FGFR2 activation compared to ICIs alone

Melanoma cell invasiveness is regulated by miR-211 suppression of the BRN2 transcription factor

To identify microRNAs potentially involved in melanomagenesis, we compared microRNA expression profiles between melanoma cell lines and cultured melanocytes. The most differentially expressed microRNA between the normal and tumor cell lines was miR-211. We focused on this pigment-cell-enriched miRNA as it is derived from the microphthalmia-associated transcription factor (MITF)-regulated gene, TRPM1 (melastatin). We find that miR-211 expression is greatly decreased in melanoma cells and melanoblasts compared to melanocytes. Bioinformatic analysis identified a large number of potential targets of miR-211, including POU3F2 (BRN2). Inhibition of miR-211 in normal melanocytes resulted in increased BRN2 protein, indicating that endogenous miR-211 represses BRN2 in differentiated cells. Over-expression of miR-211 in melanoma cell lines changed the invasive potential of the cells in vitro through directly targeting BRN2 translation. We propose a model for the apparent non-overlapping expression levels of BRN2 and MITF in melanoma, mediated by miR-211 expression