10 research outputs found
HDAC class I inhibitor domatinostat sensitizes pancreatic cancer to chemotherapy by targeting cancer stem cell compartment via FOXM1 modulation
Pancreatic ductal adenocarcinoma (PDAC) represents an unmet clinical need due to the very poor
prognosis and the lack of effective therapy. Here we investigated the potential of domatinostat (4SC-202), a new class
I histone deacetylase (HDAC) inhibitor, currently in clinical development, to sensitize PDAC to first line standard gemcitabine
(G)/taxol (T) doublet chemotherapy treatment.
Methods: Synergistic anti-tumor effect of the combined treatment was assessed in PANC1, ASPC1 and PANC28
PDAC cell lines in vitro as well as on tumor spheroids and microtissues, by evaluating combination index (CI), apoptosis,
clonogenic capability. The data were confirmed in vivo xenograft models of PANC28 and PANC1 cells in athymic
mice. Cancer stem cells (CSC) targeting was studied by mRNA and protein expression of CSC markers, by limiting
dilution assay, and by flow cytometric and immunofluorescent evaluation of CSC mitochondrial and cellular oxidative
stress. Mechanistic role of forkhead box M1 (FOXM1) and downstream targets was evaluated in FOXM1-overexpressing
PDAC cells.
Results: We showed that domatinostat sensitized in vitro and in vivo models of PDAC to chemotherapeutics commonly
used in PDAC patients management and particularly to GT doublet, by targeting CSC compartment through
the induction of mitochondrial and cellular oxidative stress. Mechanistically, we showed that domatinostat hampers
the expression and function of FOXM1, a transcription factor playing a crucial role in stemness, oxidative stress modulation
and DNA repair. Domatinostat reduced FOXM1 protein levels by downregulating mRNA expression and inducing
proteasome-mediated protein degradation thus preventing nuclear translocation correlated with a reduction of
FOXM1 target genes. Furthermore, by overexpressing FOXM1 in PDAC cells we significantly reduced domatinostatinducing
oxidative mitochondrial and cellular stress and abolished GT sensitization, both in adherent and spheroid
cells, confirming FOXM1 crucial role in the mechanisms described. Finally, we found a correlation of FOXM1 expression
with poor progression free survival in PDAC chemotherapy-treated patients
Valproic Acid Synergizes With Cisplatin and Cetuximab in vitro and in vivo in Head and Neck Cancer by Targeting the Mechanisms of Resistance
Recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) is a
devastating malignancy with a poor prognosis. The combination of cisplatin (CDDP) plus
cetuximab (CX) is one of the standard first-line treatments in this disease. However, this
therapeutic regimen is often associated with high toxicity and resistance, suggesting that
new combinatorial strategies are needed to improve its therapeutic index. In our study,
we evaluated the antitumor effects of valproic acid (VPA), a well-known antiepileptic
agent with histone deacetylase inhibitory activity, in combination with CDDP/CX doublet
in head and neck squamous cell carcinoma (HNSCC) models. We demonstrated, in
HNSCC cell lines, but not in normal human fibroblasts, that simultaneous exposure to
equitoxic doses of VPA plus CDDP/CX resulted in a clear synergistic antiproliferative and
pro-apoptotic effects. The synergistic antitumor effect was confirmed in four different
3D-self-assembled spheroid models, suggesting the ability of the combined approach
to affect also the cancer stem cells compartment. Mechanistically, VPA enhanced
DNA damage in combination treatment by reducing the mRNA expression of ERCC
Excision Repair 1, a critical player in DNA repair, and by increasing CDDP intracellular
concentration via upregulation at transcriptional level of CDDP influx channel copper
transporter 1 and downregulation of the ATPAse ATP7B involved in CDDP-export.
Valproic acid also induced a dose-dependent downregulation of epidermal growth factor
receptor (EGFR) expression and of MAPK and AKT downstream signaling pathways
and prevent CDDP- and/or CX-induced EGFR nuclear translocation, a well-known
mechanism of resistance to chemotherapy. Indeed, VPA impaired the transcription
of genes induced by non-canonical activity of nuclear EGFR, such as cyclin D1 and thymidylate synthase. Finally, we confirmed the synergistic antitumor effect also
in vivo in both heterotopic and orthotopic models, demonstrating that the combined
treatment completely blocked HNSCC xenograft tumors growth in nude mice. Overall,
the introduction of a safe and generic drug such as VPA into the conventional treatment
for R/M HNSCC represents an innovative and feasible antitumor strategy that warrants
further clinical evaluation. A phase II clinical trial exploring the combination of VPA and
CDDP/CX in R/M HNSCC patients is currently ongoing in our institute
HSP90 identified by a proteomic approach as druggable target to reverse platinum resistance in ovarian cancer
Acquired resistance to platinum (Pt)-based therapies is an urgent unmet need in the management of epithelial ovarian cancer (EOC) patients. Here, we characterized by an unbiased proteomics method three isogenic EOC models of acquired Pt resistance (TOV-112D, OVSAHO, and MDAH-2774). Using this approach, we identified several differentially expressed proteins in Pt-resistant (Pt-res) compared to parental cells and the chaperone HSP90 as a central hub of these protein networks. Accordingly, up-regulation of HSP90 was observed in all Pt-res cells and heat-shock protein 90 alpha isoform knockout resensitizes Pt-res cells to cisplatin (CDDP) treatment. Moreover, pharmacological HSP90 inhibition using two different inhibitors [17-(allylamino)-17-demethoxygeldanamycin (17AAG) and ganetespib] synergizes with CDDP in killing Pt-res cells in all tested models. Mechanistically, genetic or pharmacological HSP90 inhibition plus CDDP -induced apoptosis and increased DNA damage, particularly in Pt-res cells. Importantly, the antitumor activities of HSP90 inhibitors (HSP90i) were confirmed both ex vivo in primary cultures derived from Pt-res EOC patients ascites and in vivo in a xenograft model. Collectively, our data suggest an innovative antitumor strategy, based on Pt compounds plus HSP90i, to rechallenge Pt-res EOC patients that might warrant further clinical evaluation
Anti-VEGF Treatment–Resistant Pancreatic Cancers Secrete Proinflammatory Factors That Contribute to Malignant Progression by Inducing an EMT Cell Phenotype
Synergistic antitumor activity of histone deacetylase inhibitors and anti-ErbB3 antibody in NSCLC primary cultures via modulation of ErbB receptors expression
ErbB3, a member of the ErbB family receptors, has a key role in the development and progression of several cancers, including non-small cell lung cancer (NSCLC), and in the establishment of resistance to therapies, leading to the development of anti-ErbB3 therapies.
In this study we demonstrated, in a set of malignant pleural effusion-derived cultures of NSCLC, the synergistic antitumor effect of a histone deacetylase inhibitor (HDACi), such as vorinostat or valproic acid (VPA), in combination with the anti-ErbB3 monoclonal antibody (MoAb) A3. Synergistic interaction was observed in 2D and in 3D cultures conditions, both in fully epithelial cells expressing all ErbB receptors, and in cells that had undergone epithelial to mesenchymal transition and expressed low levels of ErbB3. We provided evidences suggesting that differential modulation of ErbB receptors by vorinostat or VPA, also at low doses corresponding to plasma levels easily reached in treated patients, is responsible for the observed synergism. In details, we showed in epithelial cells that both vorinostat and VPA induced time- and dose-dependent down-regulation of all three ErbB receptors and of downstream signaling. On the contrary, in A3-resistant mesenchymal cells, we observed time- and dose-dependent increase of mRNA and protein levels as well as surface expression of ErbB3, paralleled by down-regulation of EGFR and ErbB2. Our results suggest that the combination of a HDACi plus an anti-ErbB3 MoAb represents a viable strategy that warrants further evaluation for the treatment of NSCLC patients
Correction to: HDAC class I inhibitor domatinostat sensitizes pancreatic cancer to chemotherapy by targeting cancer stem cell compartment via FOXM1 modulation
Large oncosomes overexpressing integrin alpha-V promote prostate cancer adhesion and invasion via AKT activation
Background: Molecular markers for prostate cancer (PCa) are required to improve the early definition of patient outcomes. Atypically large extracellular vesicles (EVs), referred as "Large Oncosomes" (LO), have been identified in highly migratory and invasive PCa cells. We recently developed and characterized the DU145R80 subline, selected from parental DU145 cells as resistant to inhibitors of mevalonate pathway. DU145R80 showed different proteomic profile compared to parental DU145 cells, along with altered cytoskeleton dynamics and a more aggressive phenotype.
Methods: Immunofluorescence staining and western blotting were used to identify blebbing and EVs protein cargo. EVs, purified by gradient ultra-centrifugations, were analyzed by tunable resistive pulse sensing and multi-parametric flow cytometry approach coupled with high-resolution imaging technologies. LO functional effects were tested in vitro by adhesion and invasion assays and in vivo xenograft model in nude mice. Xenograft and patient tumor tissues were analyzed by immunohistochemistry.
Results: We found spontaneous blebbing and increased shedding of LO from DU145R80 compared to DU145 cells. LO from DU145R80, compared to those from DU145, carried increased amounts of key-molecules involved in PCa progression including integrin alpha V (αV-integrin). By incubating DU145 cells with DU145R80-derived LO we demonstrated that αV-integrin on LO surface was functionally involved in the increased adhesion and invasion of recipient cells, via AKT. Indeed either the pre-incubation of LO with an αV-integrin blocking antibody, or a specific AKT inhibition in recipient cells are able to revert the LO-induced functional effects. Moreover, DU145R80-derived LO also increased DU145 tumor engraftment in a mice model. Finally, we identified αV-integrin positive LO-like structures in tumor xenografts as well as in PCa patient tissues. Increased αV-integrin tumor expression correlated with high Gleason score and lymph node status.
Conclusions: Overall, this study is the first to demonstrate the critical role of αV-integrin positive LO in PCa aggressive features, adding new insights in biological function of these large EVs and suggesting their potential use as PCa prognostic markers
A High Percentage of BRAFV600E Alleles in Papillary Thyroid Carcinoma Predicts a Poorer Outcome
Track Reconstruction with Cosmic Ray Data at the Tracker Integration Facility
The subsystems of the CMS silicon strip tracker were integrated and commissioned at the Tracker Integration Facility (TIF) in the period from November 2006 to July 2007.
As part of the commissioning, large samples of cosmic ray data were recorded under various running conditions in the absence of a magnetic field.
Cosmic rays detected by scintillation counters were used to trigger the readout of up to 15\,\% of the final silicon strip detector, and over 4.7~million events were recorded.
This document describes the cosmic track reconstruction and presents results on the performance of track and hit reconstruction as from dedicated analyses