Correction: Establishment and characterisation of a new patient-derived model of myxoid liposarcoma with acquired resistance to trabectedin.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Fluorescence in situ hybridization (FISH) provides estimates of minute and interstitial BAP1, CDKN2A, and NF2 gene deletions in peritoneal mesothelioma.

The aim of this study was to assess the performance of fluorescence in situ hybridization (FISH) in identifying the copy number profiles of the three key peritoneal mesothelioma tumor suppressor genes BAP1, CDKN2A, and NF2, with particular emphasis on minute homozygous deletions, a copy number abnormality recently unveiled at the 3p21 (BAP1) chromosomal region using high-throughput methods. FISH was performed on 75 formalin-fixed-paraffin-embedded peritoneal mesotheliomas and recognized two types of monoallelic loss (monosomy, and hemizygous deletion) and two types of biallelic loss (canonical homozygous deletion with a complete loss of FISH signal and homozygous deletion with diminished signal). Diminished FISH signals revealed deletions occurring within the genomic region covered by the gene-specific probe and affected all three tumor suppressors. BAP1 homozygous deletions with diminished signal outnumbered canonical homozygous deletions (13 vs 3): conversely, canonical homozygous deletions were prevalent for CDKN2A (2 vs 14). Diminished signal homozygous deletion was the only pattern of biallelic loss observed for NF2 (2 cases). Hemizygous deletion mainly affected BAP1 (21 vs 6), while monosomy was prevalent for CDKN2A (14 vs 7) and particularly for NF2 where it accounts for all monoallelic losses. FISH/immunohistochemistry (BAP1, CDKN2A, and MTAP) correlation showed that all homozygous deletions, including those with diminished signals, resulted in a null BAP1 and CDKN2A immunophenotype but only canonical CDKN2A homozygous deletions resulted in MTAP loss of expression. BAP1 hemizygous deletion, but not monosomy, was also invariably associated with loss of protein expression whereas neither type of CDKN2A monoallelic loss correlated with p16 or MTAP immunohistochemistry. Array comparative genomic hybridization performed on a spontaneously emerging peritoneal mesothelioma cell line provided support for the interpretation of the FISH patterns and allowed us to extend the number of chromatin remodeling factors involved in mesothelioma to SETD7 and PCGF5, two previously unreported genes.

NR4A3 fusion proteins trigger an axon guidance switch that marks the difference between EWSR1 and TAF15 translocated extraskeletal myxoid chondrosarcomas.

Extraskeletal myxoid chondrosarcoma (EMC) is a rare sarcoma histotype with uncertain differentiation. EMC is hallmarked by the rearrangement of the NR4A3 gene, which in most cases fuses with EWSR1 or TAF15. TAF15-translocated EMC seem to feature a more aggressive course compared to EWSR1-positive EMCs, but whether the type of NR4A3 chimera impinges upon EMC biology is still largely undefined. To gain insights on this issue, a series of EMC samples (7 EWSR1-NR4A3 and 5 TAF15-NR4A3) were transcriptionally profiled. Our study unveiled that the two EMC variants display a distinct transcriptional profile and that the axon guidance pathway is a major discriminant. In particular, class 4-6 semaphorins and axonal guidance cues endowed with pro-tumorigenic activity were more expressed in TAF15-NR4A3 tumors; vice versa, class 3 semaphorins, considered to convey growth inhibitory signals, were more abundant in EWSR1-NR4A3 EMC. Intriguingly, the dichotomy in axon guidance signaling observed in the two tumor variants was recapitulated in in vitro cell models engineered to ectopically express EWSR1-NR4A3 or TAF15-NR4A3. Moreover, TAF15-NR4A3 cells displayed a more pronounced tumorigenic potential, as assessed by anchorage-independent growth. Overall, our results indicate that the type of NR4A3 chimera dictates an axon guidance switch and impacts on tumor cell biology. These findings may provide a framework for interpretation of the different clinical-pathological features of the two EMC variants and lay down the bases for the development of novel patient stratification criteria and therapeutic approaches. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Pazopanib for treatment of advanced extraskeletal myxoid chondrosarcoma: a multicentre, single-arm, phase 2 trial.

BACKGROUND: Extraskeletal myxoid chondrosarcoma is a rare sarcoma with low sensitivity to cytotoxic chemotherapy. Retrospective evidence suggests that antiangiogenic drugs could be a treatment option. We aimed to investigate the activity of pazopanib, an antiangiogenic drug, in patients with advanced extraskeletal myxoid chondrosarcoma. METHODS: In this single-arm, open-label phase 2 trial, three parallel independent cohorts of different histotypes of advanced sarcomas were recruited (extraskeletal myxoid chondrosarcoma, typical solitary fibrous tumour, and malignant-dedifferentiated solitary fibrous tumour). In each cohort, patients received pazopanib. In this Article, we report the results of the cohort of patients with advanced extraskeletal myxoid chondrosarcoma. Separate reporting of the three cohorts was prespecified in the study protocol. In this cohort, adult patients (aged ≥18 years) with a diagnosis of NR4A3-translocated, metastatic, or unresectable extraskeletal myxoid chondrosarcoma, who had Response Evaluation Criteria in Solid Tumors (RECIST) progression in the previous 6 months, and had an Eastern Cooperative Oncology Group performance status of 0-2, were enrolled at 11 study sites of the Spanish, Italian, and French sarcoma groups. Patients received oral pazopanib (800 mg/day) continuously, until disease progression, unacceptable toxicity, death, non-compliance, patient refusal, or investigator's decision. The primary endpoint was the proportion of patients achieving an objective response according to RECIST 1·1 in the modified intention-to-treat population (patients who provided consent and had a central molecularly confirmed diagnosis of extraskeletal myxoid chondrosarcoma). The safety analysis included all patients who received at least one dose of pazopanib. This study is registered with ClinicalTrials.gov, number NCT02066285. FINDINGS: Between June 24, 2014, and Jan 17, 2017, 26 patients entered the study and started pazopanib. Of these, 23 met the eligibility criteria for the modified intention-to-treat analysis. Median follow-up was 27 months (IQR 18-30). 22 patients (one patient died before the primary analysis) were evaluable for the primary endpoint: four (18% [95% CI 1-36]) had a RECIST objective response. No deaths or grade 4 adverse events occurred. The most frequent grade 3 adverse events were hypertension (nine [35%] of 26 patients), increased concentration of alanine aminotransferase (six [23%]), and increased aspartate aminotransferase (five [19%]). INTERPRETATION: Pazopanib had clinically meaningful antitumour activity in patients with progressive and advanced extraskeletal myxoid chondrosarcoma, and could be considered a suitable option after failure to respond to first-line anthracycline-based chemotherapy in these patients. FUNDING: Spanish Group for Research on Sarcomas, Italian Sarcoma Group, French Sarcoma Group, GlaxoSmithKline, and Novartis.

Identification of mutations associated with acquired resistance to sunitinib in renal cell cancer.

Sunitinib is one of the most widely used targeted therapeutics for renal cell carcinoma (RCC), but acquired resistance against targeted therapies remains a major clinical challenge. To dissect mechanisms of acquired resistance and unravel reliable predictive biomarkers for sunitinib in RCC, we sequenced the exons of 409 tumor-suppressor genes and oncogenes in paired tumor samples from an RCC patient, obtained at baseline and after development of acquired resistance to sunitinib. From newly arising mutations, we selected, using in silico prediction models, six predicted to be deleterious, located in G6PD, LRP1B, SETD2, TET2, SYNE1, and DCC. Consistently, immunoblotting analysis of lysates derived from sunitinib-desensitized RCC cells and their parental counterparts showed marked differences in the levels and expression pattern of the proteins encoded by these genes. Our further analysis demonstrates essential roles for these proteins in mediating sunitinib cytotoxicity and shows that their loss of function renders tumor cells resistant to sunitinib in vitro and in vivo. Finally, sunitinib resistance induced by continuous exposure or by inhibition of the six proteins was overcome by treatment with cabozantinib or a low-dose combination of lenvatinib and everolimus. Collectively, our results unravel novel markers of acquired resistance to sunitinib and clinically relevant approaches for overcoming this resistance in RCC.

Establishment and characterisation of a new patient-derived model of myxoid liposarcoma with acquired resistance to trabectedin.

BACKGROUND: Myxoid liposarcoma is a histological subtype of liposarcoma particularly sensitive to trabectedin. In clinical use this drug does not cause cumulative toxicity, allowing prolonged treatment, generally until disease progression. No other effective therapies are available for trabectedin-resistant patients. METHODS: Through repeated in vivo treatment in athymic nude mice, we have obtained a patient-derived xenograft with acquired resistance to trabectedin. RESULTS: At basal level, the morphology of the resistant and sensitive models did not differ, in keeping with the finding that the transcriptional profiles of the resistant and sensitive tumours were very similar. After trabectedin treatment adipogenesis was induced in the parental xenograft but not in the resistant one, as assessed by pathological and molecular analysis. A defective transcription-coupled-nucleotide excision repair in the resistant tumour due to mutation of the UVSSA gene may be implicated in the mechanism of resistance. CONCLUSIONS: This is the first in vivo model of myxoid liposarcoma with acquired resistance to trabectedin. Although further studies are necessary to characterise the resistance mechanisms, this is a useful tool for studying new therapeutic strategies to overcome trabectedin resistance in patients.

Molecular Signatures for Combined Targeted Treatments in Diffuse Malignant Peritoneal Mesothelioma.

Background-There are currently no effective therapies for diffuse malignant peritoneal mesothelioma (DMPM) patients with disease recurrence. In this study, we investigated the biology of DMPM by analyzing the EGFR family, Axl, and MET, in order to assess the presence of cross-talk between these receptors, suggesting the effectiveness of combined targeted treatments in DMPM. Method-We analyzed a series of 22 naïve epithelioid DMPM samples from a single institute, two of which showed higher-grade malignancy ("progressed"). EGFR, HER2, HER3, Axl, and MET activation and expression were investigated by biochemical analysis, real-time PCR immunofluorescence, immunohistochemistry, next-generation sequencing, miRNA, and mRNA in situ hybridization. Results-In most DMPMs, a strong EGFR activation was associated with HER2, HER3, Axl, and MET co-activation, mediated mainly by receptor heterodimerization and autocrine-paracrine loops induced by the expression of their cognate ligands. Axl expression was downregulated by miRNA34a. Mutations in MET Sema domain were exclusively found in two "progressed" DMPMs, and the combined Axl and MET inhibition reduced cellular motility in a DMPM cell line obtained from a "progressed" DMPM. Conclusion-The results indicate that the coordinated activity of multiple cross-talks between RTKs is directly involved in the biology of DMPM, suggesting the combined inhibition of PIK3 and mTOR as an effective strategy that may be easily implemented in clinical practice, and indicating that the combined inhibition of EGFR/HER2 and HER3 and of Axl and MET deserves further investigation.

Imatinib and everolimus in patients with progressing advanced chordoma: A phase 2 clinical study.

BACKGROUND: We present the results of an academic phase 2 study on imatinib plus everolimus in patients who have progressive advanced chordoma. METHODS: In January 2011, 43 adult chordoma patients were enrolled in the study and received imatinib 400 mg/day and everolimus 2.5 mg/day until progression or limiting toxicity. Eligible patients had progressed in the 6 months before study entry. PDGFRB, S6, and 4EBP1 expression and phosphorylation were evaluated by way of immunohistochemistry and/or western blotting. The primary endpoint was the overall response rate (ORR) according to Choi criteria. Secondary endpoints were RECIST 1.1 response, progression-free survival (PFS), overall survival (OS), correlation between S6/4EBP1 phosphorylation and response. RESULTS: Thirteen of 43 patients were pretreated with imatinib. Among 40 of the 43 patients who were evaluable by Choi criteria, the best responses were 9 with partial response (ORR, 20.9%), 24 with stable disease (SD) (ORR, 55.8%), and 7 with progressive disease (ORR, 16.3%). Forty-two patients were evaluable by RECIST criteria, with 1 partial response (ORR, 2.3%), 37 stable disease (ORR, 86%), and 4 progressive disease (ORR, 9.3%). The median PFS according to Choi criteria was 11.5 months (range, 4.6-17.6 months), and 58.8% and 48.1% of patients were progression-free at 9 and 12 months, respectively. The median PFS by RECIST criteria was 14 months; the median OS was 47.1 months. When assessable, S6/4EBP1 was phosphorylated in a high and moderate/low proportion of tumor cells in responsive and nonresponsive patients, respectively. Toxicity caused a temporary and definitive treatment discontinuation in 60.5% and 30.2% of patients, respectively. CONCLUSIONS: Imatinib plus everolimus showed a limited activity in progressing advanced chordoma. Interestingly, the amount of tumor cells activated for mammalian target of rapamycin effectors correlated with the response. Toxicity was not negligible.

Self-Assembled Nanomicelles as Curcumin Drug Delivery Vehicles: Impact on Solitary Fibrous Tumor Cell Protein Expression and Viability.

Solitary fibrous tumors (SFTs) are rare soft tissue sarcomas that rely on several epithelial-mesenchymal transition (EMT) protein regulators for invasion/metastatic progression. Curcumin (CUR) has several pharmacological activities, including anticancer activity and the ability to suppress the EMT process. However, poor absorption, rapid metabolism, and side effects at high doses limit the clinical applications of CUR. Here we present the results obtained by treating SFT cells with free CUR and three different CUR-loaded nanomicelles (NMs), each of which has its surface decorated with different ligands. All CUR-loaded NMs were more efficient in suppressing SFT cell viability and expression of EMT markers than CUR alone. Combined treatments with the pan-histone deacetylase dual inhibitor SAHA revealed a differential ability in inhibiting EMT markers expression and SFT cell invasiveness, depending on the NM-ligand type. Finally, combinations of photodynamic therapy and CUR-loaded NM administrations resulted in almost complete SFT cell viability abrogation 24 h after laser irradiation.

Sirolimus in Advanced Epithelioid Hemangioendothelioma: A Retrospective Case-Series Analysis from the Italian Rare Cancer Network Database.

BACKGROUND: The aim of this study was to report on sirolimus activity in a series of patients with hemangioendothelioma (HE) treated at the National Cancer Institute, Milan (Istituto Nazionale Tumori; INT) and within the Italian Rare Cancer Network ("Rete Tumori Rari"; RTR). METHODS: We retrospectively reviewed patients with advanced and progressing epithelioid hemangioendothelioma (EHE) treated with sirolimus at the INT and/or within the RTR. Pathologic review and molecular analysis for WWTR1 rearrangement were performed. Sirolimus was administered until unacceptable toxicity or progression, with the dose being adjusted to reach target plasma levels of 15-20 ng/dL. Responses were assessed using the Response Evaluation Criteria In Solid Tumors (RECIST) criteria. RESULTS: Since 2005, 18 patients (17 EHE, 1 retiform HE; 1 locally advanced, 17 metastatic; WWTR1 rearrangement: 16) have been identified, with 17/18 patients being evaluable for response. Mean sirolimus daily dose was 4.5 mg. According to RECIST, best responses in EHE were 1 partial response (PR), 12 stable disease (SD), and 3 progressive disease (PD); the patient with retiform HE also achieved a PR, lasting >2 years. Four patients with a reversed interval progression on interruption were observed. Median overall survival was 16 months, and median progression-free survival was 12 months (range 1-45), with four patients progression-free at 24 months. The clinical benefit (complete response [CR] + PR + SD >6 months) was 56 %. Seven patients receiving sirolimus experienced an increase in pleural/peritoneal effusion plus worsening of tumor-related symptoms; six of these patients died within 1-8 months from evidence of effusion progression, while a RECIST PD was assessed in two of seven patients. CONCLUSIONS: A clinical benefit was achieved in 56 % of patients receiving sirolimus, which lasted >24 months in four patients. Most patients with pleural effusion did not benefit from sirolimus and had a poor outcome.

Antiangiogenic activity of trabectedin in myxoid liposarcoma: involvement of host TIMP-1 and TIMP-2 and tumor thrombospondin-1.

Trabectedin is a marine natural product, approved in Europe for the treatment of soft tissue sarcoma and relapsed ovarian cancer. Clinical and experimental evidence indicates that trabectedin is particularly effective against myxoid liposarcomas where response is associated to regression of capillary networks. Here, we investigated the mechanism of the antiangiogenic activity of trabectedin in myxoid liposarcomas. Trabectedin directly targeted endothelial cells, impairing functions relying on extracellular matrix remodeling (invasion and branching morphogenesis) through the upregulation of the inhibitors of matrix metalloproteinases TIMP-1 and TIMP-2. Increased TIMPs synthesis by the tumor microenvironment following trabectedin treatment was confirmed in xenograft models of myxoid liposarcoma. In addition, trabectedin upregulated tumor cell expression of the endogenous inhibitor thrombospondin-1 (TSP-1, a key regulator of angiogenesis-dependent dormancy in sarcoma), in in vivo models of myxoid liposarcomas, in vitro cell lines and primary cell cultures from patients' myxoid liposarcomas. Chromatin Immunoprecipitation analysis showed that trabectedin displaced the master regulator of adipogenesis C/EBPß from the TSP-1 promoter, indicating an association between the up-regulation of TSP-1 and induction of adipocytic differentiation program by trabectedin. We conclude that trabectedin inhibits angiogenesis through multiple mechanisms, including directly affecting endothelial cells in the tumor microenvironment--with a potentially widespread activity--and targeting tumor cells' angiogenic activity, linked to a tumor-specific molecular alteration.

Periprosthetic effusions surrounding breast expander: a flow cytometric, immunohistochemical and molecular characterization.

INTRODUCTION: The synthesis of the periprosthetic capsule during implant-based breast reconstruction is the result of a coordinate cascade of inflammatory events ending in a fibrous tissue deposition around the expander or implant. Although the development of small volumes of fluid is one of the complications of prosthetic-based breast reconstruction, the characterization of the periprosthetic effusions coupled with the micro-textured devices, that have been recently introduced after the recall of macro-textured ones, is still lacking. The investigation of these periprosthetic effusions and paired capsules in terms of immunological content were the primary and secondary aims of the present study, respectively. METHODS: For this, 68 women, 41 of whom had periprosthetic effusions at the time of expander replacement with implant, were recruited. For each case, capsule and healthy dermal tissues were taken and for women with periprosthetic effusion, peripheral blood was also collected. Periprosthetic effusions and peripheral blood were characterized by cytometry while capsules and dermal tissues by immunohistochemistry and Nanostring analysis. RESULTS: The results showed an increase of Th1, Th2 lymphocytes and a HLA-DR+bright CD16+ cells (likely representing monocytes-derived macrophages) in periprosthetic effusions in respect to peripheral blood. These pro-inflammatory cells were counterbalanced by the gain of suppressive CD4 Treg cells. In the corresponding capsules, immunohistochemistry revealed the absence of Th1 cells and the presence of tissutal FOXP3 Treg. No significant difference in expression of inflammatory-related genes between capsules and dermal tissues was present. CONCLUSIONS: These results suggest the presence of a Treg-controlled inflammation in both periprosthetic effusions and capsules.

Monocytes in leukapheresis products affect the outcome of CD19-targeted CAR T-cell therapy in patients with lymphoma.

ABSTRACT: CD19-directed chimeric antigen receptor (CAR) T cells can induce durable remissions in relapsed/refractory large B-cell lymphomas (R/R LBCLs), but 60% of patients do not respond or relapse. Biological mechanisms explaining lack of response are emerging, but they are largely unsuccessful in predicting disease response at the patient level. Additionally, to maximize the cost-effectiveness of CAR T-cell therapy, biomarkers able to predict response and survival before CAR T-cell manufacturing would be desirable. We performed transcriptomic and functional evaluations of leukapheresis products in 95 patients with R/R LBCL enrolled in a prospective observational study, to identify correlates of response and survival to tisagenlecleucel and axicabtagene ciloleucel. A signature composed of 4 myeloid genes expressed by T cells isolated from leukapheresis products is able to identify patients with a very short progression-free survival (PFS), highlighting the impact of monocytes in CAR T-cell therapy response. Accordingly, response and PFS were also negatively influenced by high circulating absolute monocyte counts at the time of leukapheresis. The combined evaluation of peripheral blood monocytes at the time of leukapheresis and the 4-gene signature represents a novel tool to identify patients with R/R LBCL at very high risk of progression after CAR T-cell therapy and could be used to plan trials evaluating CAR T cells vs other novel treatments or allogeneic CAR T cells. However, it also highlights the need to incorporate monocyte depletion strategies for better CAR T production.

Receptor tyrosine kinase pathway analysis sheds light on similarities between clear-cell sarcoma and metastatic melanoma.

To highlight possible similarities and differences in receptor tyrosine kinase (RTK) and downstream signalling activation profiles between clear-cell sarcomas (CCS) and metastatic melanomas (MM), frozen, and paired-matched fixed samples of six CCS with EWSR1 rearrangement (EWSR1+), five CCS without EWSR1 rearrangement (EWSR1-), and seven MM were investigated by means of biochemical, immunohistochemical, FISH, molecular analyses, and immunofluorescence confocal microscopy. Fixed samples of a further 10 CCS and 14 MM were investigated by means of sequencing for BRAF, NRAS, and KRAS mutations and FISH analyses for the gain of chromosomes 22 and 8. RTK analysis of all CCS/MM samples showed activation of short-form (sf) recepteur d'origine nantais (RON) RTK and of PDGFRB, MET, and HER3. Analysis of downstream signaling revealed consistent phosphorylation patterns of PI3K/AKT, RSK, and the mTOR targets S6 and 4EBP1. Analysis of frozen and fixed material from 21 CCS and 21 MM showed the presence of the V600E BRAF mutation in 2/12 EWSR1+ and 3/9 EWSR1- CCS and 9/21 MM and demonstrated a significant (P < 0.001) correlation between the gain of chromosomes 22 and 8 and EWSR1- CCS. Our results show that BRAF mutation can also be present in CCS and support the proposed aberration of chromosomes 22 and 8 as a possibly useful nonrandom hallmark of EWSR1- CCS. Besides, they broaden the spectrum of the similarities of RTK pathway activation between CCS and MM, thus suggesting that new drugs found to be active in melanoma and RON inhibitors could have a role in CCS treatment. © 2011 Wiley Periodicals, Inc.

Correlation between biological and mechanical properties of extracellular matrix from colorectal peritoneal metastases in human tissues.

Peritoneal metastases (PM) are common routes of dissemination for colorectal cancer (CRC) and remain a lethal disease with a poor prognosis. The properties of the extracellular matrix (ECM) are important in cancer development; studying their changes is crucial to understand CRC-PM development. We studied the elastic properties of ECMs derived from human samples of normal and neoplastic PM by atomic force microscopy (AFM); results were correlated with patient clinical data and expression of ECM components related to metastatic spread. We show that PM progression is accompanied by stiffening of the ECM, increased cancer associated fibroblasts (CAF) activity and increased deposition and crosslinking in neoplastic matrices; on the other hand, softer regions are also found in neoplastic ECMs on the same scales. Our results support the hypothesis that local changes in the normal ECM can create the ground for growth and spread from the tumour of invading metastatic cells. We have found correlations between the mechanical properties (relative stiffening between normal and neoplastic ECM) of the ECM and patients' clinical data, like age, sex, presence of protein activating mutations in BRAF and KRAS genes and tumour grade. Our findings suggest that the mechanical phenotyping of PM-ECM has the potential to predict tumour development.

Fatty acid synthase as a new therapeutic target for HER2-positive gastric cancer.

PURPOSE: Trastuzumab is an HER2-specific agent approved as the gold-standard therapy for advanced HER2-positive (HER2+) gastric cancer (GC), but the high rate and rapid appearance of resistance limit its clinical efficacy, resulting in the need to identify new vulnerabilities. Defining the drivers influencing HER2+ cancer stem cell (CSC) maintenance/survival could represent a clinically useful strategy to counteract tumor growth and therapy resistance. Accumulating evidence show that targeting crucial metabolic hubs, as the fatty acid synthase (FASN), may be clinically relevant. METHODS: FASN protein and transcript expression were examined by WB and FACS and by qRT-PCR and GEP analyses, respectively, in trastuzumab-sensitive and trastuzumab-resistant HER2+ GC cell lines cultured in adherent (2D) or gastrosphere promoting (3D) conditions. Molecular data were analyzed in silico in public HER2+ GC datasets. The effectiveness of the FASN inhibitor TVB3166 to overcome anti-HER2 therapy resistance was tested in vitro in gastrospheres forming efficiency bioassays and in vivo in mice bearing trastuzumab-resistant GC cells. RESULTS: We compared the transcriptome profiles of HER2+ GC cells cultured in 2D versus 3D conditions finding a significant enrichment of FASN in 3D cultures. FASN upregulation significantly correlated with high stemness score and poor prognosis in HER2+ GC cases. TVB3166 treatment significantly decreased GCSCs in all cell targets. HER2 and FASN cotargeting significantly decreased the capability to form gastrospheres versus monotherapy and reduced the in vivo growth of trastuzumab-resistant GC cells. CONCLUSION: Our findings indicate that cotargeting HER2 and FASN increase the benefit of anti-HER2 therapy representing a new opportunity for metabolically combating trastuzumab-resistant HER2+ GC.

Effectiveness of irinotecan plus trabectedin on a desmoplastic small round cell tumor patient-derived xenograft.

This study exploited a novel patient-derived xenograft (PDX) of desmoplastic small round cell tumor (DSRCT), which reproduces histomorphological and molecular characteristics of the clinical tumor, to assess the activity of cytotoxic and targeted anticancer agents. Antitumor effect was moderate for doxorubicin, pazopanib and larotrectenib [maximum tumor volume inhibition (max TVI), 55-66%], while trabectedin had higher activity (max TVI, 82%). Vinorelbine, irinotecan and eribulin achieved nearly complete tumor growth inhibition (max TVI, 96-98%), although tumors regrew after the end of treatment. The combination of irinotecan with either eribulin or trabectedin resulted in complete responses, which were maintained until the end of the experiment for irinotecan plus trabectedin. Irinotecan-based combinations nearly abrogated the expression of proteins of the G2/M checkpoint, preventing cell entrance in mitosis, and induced apoptotic and necroptotic cell death. Consistently, irinotecan plus trabectedin resulted in reprogramming of DSCRT transcriptome, with downregulation of E2F targets, G2/M checkpoint and mitotic spindle gene sets. This study emphasizes the importance of patient-derived preclinical models to explore new treatments for DSRCT and fosters clinical investigation into the activity of irinotecan plus trabectedin.

A2AR Expression and Immunosuppressive Environment Independent of KRAS and GNAS Mutations in Pseudomyxoma Peritonei.

In pseudomyxoma peritonei (PMP), KRAS and GNAS mutations are frequent. We hypothesized that these mutations may contribute to the suppression of antitumor immunity: KRAS may induce GMCSF expression, while GNAS may enhance the expression of cyclic adenosine monophosphate and A2AR signaling. This study aimed to explore possible mechanisms facilitated by KRAS and GNAS mutations for escaping immune surveillance. Additionally, we looked for new potential therapeutic and prognostic targets in this rare disease which is poorly characterized at the molecular level. GM-CSF, A2AR, CD73, CD39, and PD-L1 expression was investigated by immunohistochemistry in 40 PMPs characterized for GNAS and KRAS mutational status. Immune cell populations were studied by immunohistochemistry and nanostring nCounter®. Following the criteria of a prognostic nomogram reported for PMP, we stratified the patients into two different risk groups, with 28 "low-risk" and 12 "high-risk" patients. We observed the expression of GM-CSF (74%); CD39 (37%); CD73 (53%); A2AR (74%); and PD-L1 (16%) which was unrelated to GNAS or KRAS status. The tumor microenvironment showed the presence of CD4+ T cells (86%); CD8+ T cells (27%); CD20+ B (67%); CD15+ cells (86%); and CD163+ M2 macrophages (67%), while CD56+ NK cells were absent. CD163 expression (27%) in PMP tumor cells was associated with poor prognosis. GNAS mutation and A2AR expression were not associated with a specific immune transcriptional signature. However, the expression assay revealed 21 genes associated with prognosis. The "high-risk" patients exhibited worse progression-free survival (HR = 2.3, CI 95%: 1.1-5.1, p = 0.034) and significant downregulation of MET, IL8, PPARG, DTX4, HMGA1, ZIC2, WNT5B, and CCRL2. In conclusion, we documented the presence of immunosuppressive factors such as GM-CSF, A2AR, and PD-L1 in PMP. These factors were not associated with GNAS and KRAS status and could be explored as therapeutic molecular targets. Additionally, a set of potential prognostic biomarkers, including CD163 expression in tumor cells, deserve further investigation.

Guadecitabine plus ipilimumab in unresectable melanoma: five-year follow-up and integrated multi-omic analysis in the phase 1b NIBIT-M4 trial.

Association with hypomethylating agents is a promising strategy to improve the efficacy of immune checkpoint inhibitors-based therapy. The NIBIT-M4 was a phase Ib, dose-escalation trial in patients with advanced melanoma of the hypomethylating agent guadecitabine combined with the anti-CTLA-4 antibody ipilimumab that followed a traditional 3 + 3 design (NCT02608437). Patients received guadecitabine 30, 45 or 60 mg/m2/day subcutaneously on days 1 to 5 every 3 weeks starting on week 0 for a total of four cycles, and ipilimumab 3 mg/kg intravenously starting on day 1 of week 1 every 3 weeks for a total of four cycles. Primary outcomes of safety, tolerability, and maximum tolerated dose of treatment were previously reported. Here we report the 5-year clinical outcome for the secondary endpoints of overall survival, progression free survival, and duration of response, and an exploratory integrated multi-omics analysis on pre- and on-treatment tumor biopsies. With a minimum follow-up of 45 months, the 5-year overall survival rate was 28.9% and the median duration of response was 20.6 months. Re-expression of immuno-modulatory endogenous retroviruses and of other repetitive elements, and a mechanistic signature of guadecitabine are associated with response. Integration of a genetic immunoediting index with an adaptive immunity signature stratifies patients/lesions into four distinct subsets and discriminates 5-year overall survival and progression free survival. These results suggest that coupling genetic immunoediting with activation of adaptive immunity is a relevant requisite for achieving long term clinical benefit by epigenetic immunomodulation in advanced melanoma patients.

Decellularized extracellular matrix as scaffold for cancer organoid cultures of colorectal peritoneal metastases.

Peritoneal metastases (PM) from colorectal cancer (CRC) are associated with poor survival. The extracellular matrix (ECM) plays a fundamental role in modulating the homing of CRC metastases to the peritoneum. The mechanisms underlying the interactions between metastatic cells and the ECM, however, remain poorly understood, and the number of in vitro models available for the study of the peritoneal metastatic process is limited. Here, we show that decellularized ECM of the peritoneal cavity allows the growth of organoids obtained from PM, favoring the development of three-dimensional (3D) nodules that maintain the characteristics of in vivo PM. Organoids preferentially grow on scaffolds obtained from neoplastic peritoneum, which are characterized by greater stiffness than normal scaffolds. A gene expression analysis of organoids grown on different substrates reflected faithfully the clinical and biological characteristics of the organoids. An impact of the ECM on the response to standard chemotherapy treatment for PM was also observed. The ex vivo 3D model, obtained by combining patient-derived decellularized ECM with organoids to mimic the metastatic niche, could be an innovative tool to develop new therapeutic strategies in a biologically relevant context to personalize treatments.