Biology subjects

Jachetti, E.

Publications and source records attributed to Jachetti, E..

4 recordsLinked to original sources

bioRxiv2026

ENPP3 expressed by HER2-positive breast cancer cells is associated with good prognosis by restraining epithelial-to-mesenchymal phenotype

Background Ectonucleotide pyrophosphatase/phosphodiesterase 3 (ENPP3/CD203c) is largely studied as a marker of mast cells and basophils. By depleting extracellular ATP, it prevents excessive activation of mast cells and basophils, hence reducing inflammation and allergic reactions. Recent findings have also shown that Enpp3 can deplete cGAMP, another molecule involved in STING activation and IFN-mediated pro-inflammation. Little is still known regarding the role of Enpp3 in non-immune cells although a few reports have described its expression in healthy tissues and tumors. Methods In silico analysis were performed to investigate the expression levels and the prognostic value of Enpp3 in breast cancer, together with ovarian, prostate and colon carcinoma. ENPP3 expression was evaluated in formalin-fixed, paraffin-embedded tumor samples of breast cancer patients by immunohistochemistry, and in mouse mammary cancer cell lines by western blots. Cells were treated with EGFR ligands to stimulate the EGFR/HER2 axis. A mouse-derived mammary cancer cell line was engineered by CRISPR/Cas9 to introduce a GFP sequence under the control of the Enpp3 promoter. GFP-positive and -negative cells were sorted and analyzed by gene expression profiling to identify genes and pathways associated with Enpp3 expression. Finally, wild type and Enpp3 knockout cells were injected in the fat pad of Wsh mice, which do not have mast cells, to evaluate the growth of the tumors which were further analyzed by immunohistochemistry. Results We provide evidence that HER2-positive cells express higher levels of ENPP3 in samples of breast cancer patients. Moreover, in vitro models confirmed that HER2 expression and EGFR stimulation result in up-regulation of Enpp3. We identified pathways that can concur to Enpp3 expression and showed that in vivo the absence of Enpp3 promotes tumor growth and development of tumors with a marked epithelial-to-mesenchymal phenotype. Finally, in a small cohort of HER2-positive breast cancer patients, we found that ENPP3 expression correlates with increased relapse-free survival. Conclusions Despite its potential immunosuppressive role, our findings support the notion that ENPP3 expression is promoted by HER2 in breast cancer, and that it is endowed with a positive prognostic value.

cancer biology↗

bioRxiv2026

Pharmacological targeting of EED is an effective therapeutic strategy in cellular models of incurable neuroendocrine prostate cancer

BackgroundNeuroendocrine Prostate Cancer (NEPC) is an incurable malignancy, originating from the trans-differentiation of prostate adenocarcinoma (PRAD). Compared to PRAD, NEPC shows over-activation of Polycomb Repressive complex-1(PRC1) and-2 (PRC2), which are multiprotein epigenetic writers that drive cancer progression via tumour suppressor gene silencing. Tazemetostat is a PRC2 inhibitor approved for the treatment of sarcomas and lymphomas. ORIC-944 is a novel EED (Embryonic Ectoderm Development) inhibitor, which is being tested in clinical trials. EED is an attractive target as it functions as a key component of both PRC1 and PRC2. Objective and MethodsWe compared the anticancer effects of tazemetostat and ORIC-944 in NEPC and PRAD cells. Cells were exposed to various concentrations of the two compounds to measure effects on cell viability (IC50) and apoptosis (flow cytometry). PRC2 inhibition was confirmed by measuring histone H3 Lys 27 trimethylation (H3K27me3) via ELISA and Western Blot. RNA Sequencing and pathway analysis was conducted to study modes of actions of tazemetostat vs ORIC-944. ResultsUnlike tazemetostat, ORIC-944 causes dose-dependent growth inhibition in both NEPC and PRAD cells. In this context, EED targeting achieves IC50 values that are comparable to those of compounds used for the clinical treatment of advanced prostate cancer. Moreover, ORIC-944 (but not tazemetostat) causes significant apoptosis in NEPC cells. Both tazemetostat and ORIC-944 reduce H3K27me3. Mechanistically, both compounds reactivate the expression of known PRC2 targets, such as genes that control neural differentiation. However, the EED inhibitor also reactivates PRC1 targets, including pro-apoptotic and anti-proliferating genes (e.g. metallothionines). This evidence suggests that EED inhibition is a promising therapeutic strategy for NEPC.

cancer biology↗

bioRxiv2024

EHZ2 inhibition enhances the activity of platinum chemotherapy in aggressive variant prostate cancer

BackgroundEZH2 promotes aggressive-variant prostate cancer (AVPC) progression via histone H3-Lysine-27 tri-methylation (H3K27me3). We hypothesize that epigenetic reprogramming via EZH2 inhibitors (EZH2i) improves the efficacy of chemotherapy in AVPC. MethodsWe studied the expression of EZH2 in clinical prostate cancer cohorts (bioinformatics). We determined the effect of EZH2i on both cellular- and cell-free-H3K27me3 levels. We measured effects of carboplatin with/without EZH2i on AVPC cell viability (IC50). We studied how EZH2i modulate gene expression (RNA Seq). ResultsEZH2 was significantly up-regulated in AVPC vs other prostate cancer types. EZH2i reduced both cellular and cell free-H3K27me3 levels. EZH2i significantly reduced carboplatin IC50. EZH2i reduced the expression of DNA repair and increased the expression of pro-apoptotic genes. Article HighlightsO_LIPolycomb-mediated gene silencing promotes prostate cancer progression C_LIO_LIAggressive-variant prostate cancers (AVPCs) are characterized by increased activity of the Polycomb-Repressive Complex 2 (PRC2) C_LIO_LIHere we show that PRC2 inhibitors are scarcely effective as monotherapy in ACPC cells C_LIO_LIHowever the combination of PRC2 inhibitors and carboplatin is highly synergistic C_LIO_LIRNA Seq studies revealed that PRC2 inhibitors enhance carboplatin activity by modulating several key pathways, including DNA repair and apoptosis. C_LI

pharmacology and toxicology↗

bioRxiv2021

Neutrophil extracellular traps arm DC vaccination against NPM-mutant myeloproliferation

Neutrophil extracellular traps (NET) are web-like chromatin structures composed by dsDNA and histones, decorated with anti-microbial proteins. Their interaction with dendritic cells (DC) allows DC activation and maturation toward presentation of NET-associated antigens. Differently from other types of cell death that imply protein denaturation, NETosis preserves the proteins localized onto the DNA threads for proper enzymatic activity and conformational status, including immunogenic epitopes. Besides neutrophils, leukemic cells can release extracellular traps displaying leukemia-associated antigens, prototypically mutant nucleophosmin (NPMc+) that upon mutation translocates from nucleolus to the cytoplasm localizing onto NET threads. We tested NPMc+ immunogenicity through a NET/DC vaccine to treat NPMc-driven myeloproliferation in transgenic and transplantable models. Vaccination with DC loaded with NPMc+ NET (NPMc+ NET/DC) reduced myeloproliferation in transgenic mice, favoring the development of antibodies to mutant NPMc and and the induction of a CD8+ T cell response. The efficacy of this vaccine was also tested in mixed NPMc/WT bone marrow chimeras in a competitive bone marrow transplantation setting, where the NPMc+ NET/DC vaccination impaired the expansion of NPMc+ in favor of WT myeloid compartment. NPMc+ NET/DC vaccination also achieved control of an aggressive leukemia transduced with mutant NPMc, effectively inducing an anti-leukemia CD8 T cell memory response. eTOC SummaryNPMc is an AML-triggering mutation inducing translocation of NPM into the cytoplasm, allowing its association to NET threads. On NET, NPMc becomes immunogenic acting as an alarmin and exposing immunogenic peptides. We demonstrate that NET can be exploited as anti-tumor weapons in DC-based vaccination strategies.

immunology↗