The cross-talk between the macro and micro-environment in precursor lesions of pancreatic cancer leads to new and promising circulating biomarkers.

Pancreatic cancer (PC) is a clinically challenging tumor to combat due to its advanced stage at diagnosis as well as its resistance to currently available therapies. The absence of early symptoms and known detectable biomarkers renders this disease incredibly difficult to detect/manage. Recent advances in the understanding of PC biology have highlighted the importance of cancer-immune cell interactions, not only in the tumor micro-environment but also in distant systemic sites, like the bone marrow, spleen and circulating immune cells, the so-called macro-environment. The response of the macro-environment is emerging as a determining factor in tumor development by contributing to the formation of an increasingly immunogenic micro-environment promoting tumor homeostasis and progression. We will summarize the key events associated with the feedback loop between the tumor immune micro-environment (TIME) and the tumor immune macroenvironment (TIMaE) in pancreatic precancerous lesions along with how it regulates disease development and progression. In addition, liquid biopsy biomarkers capable of diagnosing PC at an early stage of onset will also be discussed. A clearer understanding of the early crosstalk between micro-environment and macro-environment could contribute to identifying new molecular therapeutic targets and biomarkers, consequently improving early PC diagnosis and treatment.

Paper-based electrochemical device for early detection of integrin αvß6 expressing tumors.

Despite progress in the prevention and diagnosis of cancer, current technologies for tumor detection present several limitations including invasiveness, toxicity, inaccuracy, lengthy testing duration and high cost. Therefore, innovative diagnostic techniques that integrate knowledge from biology, oncology, medicinal and analytical chemistry are now quickly emerging in the attempt to address these issues. Following this approach, here we developed a paper-based electrochemical device for detecting cancer-derived Small Extracellular Vesicles (S-EVs) in fluids. S-EVs were obtained from cancer cell lines known to express, at a different level, the αvß6 integrin receptor, a well-established hallmark of numerous epithelial cancer types. The resulting biosensor turned out to recognize αvß6-containing S-EVs down to a limit of 0.7*103 S-EVs/mL with a linear range up to 105 S-EVs /mL, and a relative standard deviation of 11%, thus it may represent a novel opportunity for αvß6 expressing cancers detection.

New Insights into the Identification of Metabolites and Cytokines Predictive of Outcome for Patients with Severe SARS-CoV-2 Infection Showed Similarity with Cancer.

SARS-CoV-2 infection is characterized by several clinical manifestations, ranging from the absence of symptoms to severe forms that necessitate intensive care treatment. It is known that the patients with the highest rate of mortality develop increased levels of proinflammatory cytokines, called the "cytokine storm", which is similar to inflammatory processes that occur in cancer. Additionally, SARS-CoV-2 infection induces modifications in host metabolism leading to metabolic reprogramming, which is closely linked to metabolic changes in cancer. A better understanding of the correlation between perturbed metabolism and inflammatory responses is necessary. We evaluated untargeted plasma metabolomics and cytokine profiling via 1H-NMR (proton nuclear magnetic resonance) and multiplex Luminex assay, respectively, in a training set of a limited number of patients with severe SARS-CoV-2 infection classified on the basis of their outcome. Univariate analysis and Kaplan-Meier curves related to hospitalization time showed that lower levels of several metabolites and cytokines/growth factors, correlated with a good outcome in these patients and these data were confirmed in a validation set of patients with similar characteristics. However, after the multivariate analysis, only the growth factor HGF, lactate and phenylalanine retained a significant prediction of survival. Finally, the combined analysis of lactate and phenylalanine levels correctly predicted the outcome of 83.3% of patients in both the training and the validation set. We highlighted that the cytokines and metabolites involved in COVID-19 patients' poor outcomes are similar to those responsible for cancer development and progression, suggesting the possibility of targeting them by repurposing anticancer drugs as a therapeutic strategy against severe SARS-CoV-2 infection.

HDAC class I inhibitor domatinostat sensitizes pancreatic cancer to chemotherapy by targeting cancer stem cell compartment via FOXM1 modulation.

BACKGROUND: 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 domatinostat-inducing 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. CONCLUSIONS: Overall, we suggest a novel therapeutic strategy based on domatinostat to improve efficacy and to overcome resistance of commonly used chemotherapeutics in PDAC that warrant further clinical evaluation.

Epigenetic Approaches to Overcome Fluoropyrimidines Resistance in Solid Tumors.

Although fluoropyrimidines were introduced as anticancer agents over 60 years ago, they are still the backbone of many combination chemotherapy regimens for the treatment of solid cancers. Like other chemotherapeutic agents, the therapeutic efficacy of fluoropyrimidines can be affected by drug resistance and severe toxicities; thus, novel therapeutic approaches are required to potentiate their efficacy and overcome drug resistance. In the last 20 years, the deregulation of epigenetic mechanisms has been shown to contribute to cancer hallmarks. Histone modifications play an important role in directing the transcriptional machinery and therefore represent interesting druggable targets. In this review, we focused on histone deacetylase inhibitors (HDACis) that can increase antitumor efficacy and overcome resistance to fluoropyrimidines by targeting specific genes or proteins. Our preclinical data showed a strong synergistic interaction between HDACi and fluoropyrimidines in different cancer models, but the clinical studies did not seem to confirm these observations. Most likely, the introduction of increasingly complex preclinical models, both in vitro and in vivo, cannot recapitulate human complexity; however, our analysis of clinical studies revealed that most of them were designed without a mechanistic approach and, importantly, without careful patient selection.

Plasma metabolomics, lipidomics and cytokinomics profiling predict disease recurrence in metastatic colorectal cancer patients undergoing liver resection.

Purpose: In metastatic colorectal cancer (mCRC) patients (pts), treatment strategies integrating liver resection with induction chemotherapy offer better 5-year survival rates than chemotherapy alone. However, liver resection is a complex and costly procedure, and recurrence occurs in almost 2/3rds of pts, suggesting the need to identify those at higher risk. The aim of this work was to evaluate whether the integration of plasma metabolomics and lipidomics combined with the multiplex analysis of a large panel of plasma cytokines can be used to predict the risk of relapse and other patient outcomes after liver surgery, beyond or in combination with clinical morphovolumetric criteria. Experimental design: Peripheral blood metabolomics and lipidomics were performed by 600 MHz NMR spectroscopy on plasma from 30 unresectable mCRC pts treated with bevacizumab plus oxaliplatin-based regimens within the Obelics trial (NCT01718873) and subdivided into responder (R) and non-R (NR) according to 1-year disease-free survival (DFS): ≥ 1-year (R, n = 12) and < 1-year (NR, n = 18). A large panel of cytokines, chemokines, and growth factors was evaluated on the same plasma using Luminex xMAP-based multiplex bead-based immunoassay technology. A multiple biomarkers model was built using a support vector machine (SVM) classifier. Results: Sparse partial least squares discriminant analysis (sPLS-DA) and loading plots obtained by analyzing metabolomics profiles of samples collected at the time of response evaluation when resectability was established showed significantly different levels of metabolites between the two groups. Two metabolites, 3-hydroxybutyrate and histidine, significantly predicted DFS and overall survival. Lipidomics analysis confirmed clear differences between the R and NR pts, indicating a statistically significant increase in lipids (cholesterol, triglycerides and phospholipids) in NR pts, reflecting a nonspecific inflammatory response. Indeed, a significant increase in proinflammatory cytokines was demonstrated in NR pts plasma. Finally, a multiple biomarkers model based on the combination of presurgery plasma levels of 3-hydroxybutyrate, cholesterol, phospholipids, triglycerides and IL-6 was able to correctly classify patients by their DFS with good accuracy. Conclusion: Overall, this exploratory study suggests the potential of these combined biomarker approaches to predict outcomes in mCRC patients who are candidates for liver metastasis resection after induction treatment for defining personalized management and treatment strategies.

Effect of Bevacizumab in Combination With Standard Oxaliplatin-Based Regimens in Patients With Metastatic Colorectal Cancer: A Randomized Clinical Trial.

Importance: Although bevacizumab is a standard of care in combination treatments for metastatic colorectal cancer (mCRC), its clinical benefit has been limited. Objective: To determine whether sequential scheduling of bevacizumab administration in combination with chemotherapy improves treatment efficacy in patients with mCRC, in keeping with the tumor vascular normalization hypothesis. Design, Setting, and Participants: This open-label, randomized clinical phase 3 trial was conducted from May 8, 2012, to December 9, 2015, at 3 Italian centers. Patients aged 18 to 75 years with unresectable, previously untreated, or single line-treated mCRC were recruited. Follow-up was completed December 31, 2019, and data were analyzed from February 26 to July 24, 2020. Interventions: Patients received 12 biweekly cycles of standard oxaliplatin-based regimens (modified FOLFOX-6 [levo-folinic acid, fluorouracil, and oxaliplatin]/modified CAPOX [capecitabine and oxaliplatin]) plus bevacizumab administered either on the same day as chemotherapy (standard arm) or 4 days before chemotherapy (experimental arm). Main Outcomes and Measures: The primary end point was the objective response rate (ORR) measured with Response Evaluation Criteria in Solid Tumors, version 1.1. Secondary end points included progression-free survival, overall survival, safety, and quality of life (QOL). Results: Overall, 230 patients (136 men [59.1%]; median age, 62.3 [interquartile range, 53.3-67.6] years) were randomly assigned to the standard arm (n = 115) or the experimental arm (n = 115). The median duration of follow-up was 68.3 (95% CI, 61.0-70.0) months. No difference in ORR (57.4% [95% CI, 47.8%-66.6%] in the standard arm and 56.5% [95% CI, 47.0-65.7] in the experimental arm; P = .89) or progression-free survival (10.5 [95% CI, 9.1-12.3] months in the standard arm and 11.7 [95% CI, 9.9-12.9] months in the experimental arm; P = .15) was observed. However, the median overall survival was 29.8 (95% CI, 22.5-41.1) months in the experimental arm compared with 24.1 (95% CI, 18.6-29.8) months in the standard arm (adjusted hazard ratio, 0.73; 95% CI, 0.54-0.99; P = .04). Moreover, the experimental arm was associated with a significant reduction in the rate of severe diarrhea (6 [5.3%] vs 19 [16.5%]; P = .006) and nausea (2 [1.8%] vs 8 [7.0%]; P = .05) and improved physical functioning (mean [SD] change from baseline, 0.65 [1.96] vs -7.41 [2.95] at 24 weeks; P = .02), and constipation scores (mean [SD] change from baseline, -17.2 [3.73] vs -0.62 [4.44]; P = .003). Conclusions and Relevance: In this randomized clinical trial, sequential administration of bevacizumab plus chemotherapy did not improve ORR, the primary end point. However, the overall survival advantage, fewer adverse effects, and better health-related QOL associated with sequential bevacizumab administration might provide the basis for exploring antiangiogenic combination treatments with innovative perspectives. Trial Registration: EudraCT Identifier: 2011-004997-27; ClinicalTrials.gov Identifier: NCT01718873.

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.

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.

Synergistic antitumor interaction of valproic acid and simvastatin sensitizes prostate cancer to docetaxel by targeting CSCs compartment via YAP inhibition.

BACKGROUND: Despite the introduction of several novel therapeutic approaches that improved survival, metastatic castration-resistant prostate cancer (mCRPC) remains an incurable disease. Herein we report the synergistic antitumor interaction between two well-known drugs used for years in clinical practice, the antiepileptic agent with histone deacetylase inhibitory activity valproic acid and the cholesterol lowering agent simvastatin, in mCRPC models. METHODS: Synergistic anti-tumor effect was assessed on PC3, 22Rv1, DU145, DU145R80, LNCaP prostate cancer cell lines and EPN normal prostate epithelial cells, by calculating combination index (CI), caspase 3/7 activation and colony formation assays as well as on tumor spheroids and microtissues scored with luminescence 3D-cell viability assay. Cancer stem cells (CSC) compartment was studied evaluating specific markers by RT-PCR, western blotting and flow cytometry as well as by limiting dilution assay. Cholesterol content was evaluated by 1H-NMR. Overexpression of wild-type YAP and constitutively active YAP5SA were obtained by lipofectamine-based transfection and evaluated by immunofluorescence, western blotting and RT-PCR. 22Rv1 R_39 docetaxel resistant cells were selected by stepwise exposure to increasing drug concentrations. In vivo experiments were performed on xenograft models of DU145R80, 22Rv1 parental and docetaxel resistant cells, in athymic mice. RESULTS: We demonstrated the capacity of the combined approach to target CSC compartment by a novel molecular mechanism based on the inhibition of YAP oncogene via concurrent modulation of mevalonate pathway and AMPK. Because both CSCs and YAP activation have been associated with chemo-resistance, we tested if the combined approach can potentiate docetaxel, a standard of care in mCRCP treatment. Indeed, we demonstrated, both in vitro and in vivo models, the ability of valproic acid/simvastatin combination to sensitize mCRPC cells to docetaxel and to revert docetaxel-resistance, by mevalonate pathway/YAP axis modulation. CONCLUSION: Overall, mCRPC progression and therapeutic resistance driven by CSCs via YAP, can be tackled by the combined repurposing of two generic and safe drugs, an approach that warrants further clinical development in this disease.

Randomized phase II study of valproic acid in combination with bevacizumab and oxaliplatin/fluoropyrimidine regimens in patients with RAS-mutated metastatic colorectal cancer: the REVOLUTION study protocol.

BACKGROUND: Despite effective treatments, metastatic colorectal cancer (mCRC) prognosis is still poor, mostly in RAS-mutated tumors, thus suggesting the need for novel combinatorial therapies. Epigenetic alterations play an important role in initiation and progression of cancers, including CRC. Histone-deacetylase inhibitors (HDACi) have shown activity in combination with chemotherapy in the treatment of solid tumors. Owing to its HDACi activity and its safe use for epileptic disorders, valproic acid (VPA) is a good candidate for anticancer therapy that we have largely explored preclinically translating our findings in currently ongoing clinical studies. We have shown in CRC models that HDACi, including VPA, induces synergistic antitumor effects in combination with fluoropyrimidines. Furthermore, unpublished results from our group demonstrated that VPA induces differentiation and sensitization of CRC stem cells to oxaliplatin. Moreover, preclinical and clinical data suggest that HDACi may prevent/reverse anti-angiogenic resistance. METHODS/DESIGN: A randomized, open-label, two-arm, multicenter phase-II study will be performed to explore whether the addition of VPA to first line bevacizumab/oxaliplatin/fluoropyrimidine regimens (mFOLFOX-6/mOXXEL) might improve progression-free survival (PFS) in RAS-mutated mCRC patients. A sample size of 200 patients was calculated under the hypothesis that the addition of VPA to chemotherapy/bevacizumab can improve PFS from 9 to 12 months, with one-sided alpha of 0.20 and a power of 0.80. Secondary endpoints are overall survival, objective response rate, metastases resection rate, toxicity, and quality of life. Moreover, the study will explore several prognostic and predictive biomarkers on blood samples, primary tumors, and on resected metastases. DISCUSSION: The "Revolution" study aims to improve the treatment efficacy of RAS-mutated mCRC through an attractive strategy evaluating the combination of VPA with standard cancer treatment. Correlative studies could identify novel biomarkers and could add new insight in the mechanism of interaction between VPA, fluoropyrimidine, oxaliplatin, and bevacizumab. TRIAL REGISTRATION: EudraCT: 2018-001414-15; ClinicalTrials.gov identifier: NCT04310176.

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.

Implication for Cancer Stem Cells in Solid Cancer Chemo-Resistance: Promising Therapeutic Strategies Based on the Use of HDAC Inhibitors.

Resistance to therapy in patients with solid cancers represents a daunting challenge that must be addressed. Indeed, current strategies are still not effective in the majority of patients; which has resulted in the need for novel therapeutic approaches. Cancer stem cells (CSCs), a subset of tumor cells that possess self-renewal and multilineage differentiation potential, are known to be intrinsically resistant to anticancer treatments. In this review, we analyzed the implications for CSCs in drug resistance and described that multiple alterations in morphogenetic pathways (i.e. Hippo, Wnt, JAK/STAT, TGF-, Notch, Hedgehog pathways) were suggested to be critical for CSC plasticity. By interrogating The Cancer Genome Atlas (TCGA) datasets, we first analyzed the prevalence of morphogenetic pathways alterations in solid tumors with associated outcomes. Then, by highlighting epigenetic relevance in CSC development and maintenance, we selected histone deacetylase inhibitors (HDACi) as potential agents of interest to target this subpopulation based on the pleiotropic effects exerted specifically on altered morphogenetic pathways. In detail, we highlighted the role of HDACi in solid cancers and,specifically,in the CSC subpopulation and we pointed out some mechanisms by which HDACi are able to overcome drug resistance and to modulate stemness. Although, further clinical and preclinical investigations should be conducted to disclose the unclear mechanisms by which HDACi modulate several signaling pathways in different tumors. To date, several lines of evidence support the testing of novel combinatorial therapeutic strategies based on the combination of drugs commonly used in clinical practice and HDACi to improve therapeutic efficacy in solid cancer patients.

Vorinostat Potentiates 5-Fluorouracil/Cisplatin Combination by Inhibiting Chemotherapy-Induced EGFR Nuclear Translocation and Increasing Cisplatin Uptake.

The 5-fluorouracil/cisplatin (5FU/CDDP) combination is one of the most widely used treatment options for several solid tumors. However, despite good anticancer responses, this regimen is often associated with high toxicity and treatment resistance. In our study, we evaluated whether the histone deacetylase inhibitor (HDACi), vorinostat, may induce synergistic antitumor and proapoptotic effects in combination with 5FU/CDDP in squamous cancer cell models. We demonstrated in cancer cell lines, including the intrinsic CDDP-resistant Cal27 cells, that simultaneous exposure to equitoxic doses of vorinostat plus 5FU/CDDP results in strong synergistic antiproliferative and proapoptotic effects related to cell-cycle perturbation and DNA damage induction. These effects were confirmed in vivo in both orthotopic and heterotopic xenograft mouse models of Cal27 cells. Mechanistically, vorinostat reverted 5FU/CDDP-induced EGFR phosphorylation and nuclear translocation, leading to the impairment of nuclear EGFR noncanonical induction of genes such as thymidylate synthase and cyclin D1. These effects were exerted by vorinostat, at least in part, by increasing lysosomal-mediated EGFR protein degradation. Moreover, vorinostat increased platinum uptake and platinated DNA levels by transcriptionally upregulating the CDDP influx channel copper transporter 1 (CTR1). Overall, to our knowledge, this study is the first to demonstrate the ability of vorinostat to inhibit two well-known mechanisms of CDDP resistance, EGFR nuclear translocation and CTR1 overexpression, adding new insight into the mechanism of the synergistic interaction between HDACi- and CDDP-based chemotherapy and providing the rationale to clinically explore this combination to overcome dose-limiting toxicity and chemotherapy resistance.

A standardized flow cytometry network study for the assessment of circulating endothelial cell physiological ranges.

Circulating endothelial cells (CEC) represent a restricted peripheral blood (PB) cell subpopulation with high potential diagnostic value in many endothelium-involving diseases. However, whereas the interest in CEC studies has grown, the standardization level of their detection has not. Here, we undertook the task to align CEC phenotypes and counts, by standardizing a novel flow cytometry approach, within a network of six laboratories. CEC were identified as alive/nucleated/CD45negative/CD34bright/CD146positive events and enumerated in 269 healthy PB samples. Standardization was demonstrated by the achievement of low inter-laboratory Coefficients of Variation (CVL), calculated on the basis of Median Fluorescence Intensity values of the most stable antigens that allowed CEC identification and count (CVL of CD34bright on CEC ~ 30%; CVL of CD45 on Lymphocytes ~ 20%). By aggregating data acquired from all sites, CEC numbers in the healthy population were captured (medianfemale = 9.31 CEC/mL; medianmale = 11.55 CEC/mL). CEC count biological variability and method specificity were finally assessed. Results, obtained on a large population of donors, demonstrate that the established procedure might be adopted as standardized method for CEC analysis in clinical and in research settings, providing a CEC physiological baseline range, useful as starting point for their clinical monitoring in endothelial dysfunctions.

Synergistic antitumor interaction between valproic acid, capecitabine and radiotherapy in colorectal cancer: critical role of p53.

BACKGROUND: Recurrence with distant metastases has become the predominant pattern of failure in locally advanced rectal cancer (LARC), thus the integration of new antineoplastic agents into preoperative fluoropyrimidine-based chemo-radiotherapy represents a clinical challenge to implement an intensified therapeutic strategy. The present study examined the combination of the histone deacetylase inhibitor (HDACi) valproic acid (VPA) with fluoropyrimidine-based chemo-radiotherapy on colorectal cancer (CRC) cells. METHODS: HCT-116 (p53-wild type), HCT-116 p53-/- (p53-null), SW620 and HT29 (p53-mutant) CRC cell lines were used to assess the antitumor interaction between VPA and capecitabine metabolite 5'-deoxy-5-fluorouridine (5'-DFUR) in combination with radiotherapy and to evaluate the role of p53 in the combination treatment. Effects on proliferation, clonogenicity and apoptosis were evaluated, along with γH2AX foci formation as an indicator for DNA damage. RESULTS: Combined treatment with equipotent doses of VPA and 5'-DFUR resulted in synergistic effects in CRC lines expressing p53 (wild-type or mutant). In HCT-116 p53-/- cells we observed antagonist effects. Radiotherapy further potentiated the antiproliferative, pro-apoptotic and DNA damage effects induced by 5'-DFUR/VPA combination in p53 expressing cells. CONCLUSIONS: These results highlighted the role of VPA as valuable candidate to be added to preoperative chemo-radiotherapy in LARC. On these bases we launched the ongoing phase I/II study of VPA and short-course radiotherapy plus capecitabine as preoperative treatment in low-moderate risk rectal cancer (V-shoRT-R3).

Tissue transglutaminase (TG2) is involved in the resistance of cancer cells to the histone deacetylase (HDAC) inhibitor vorinostat.

Vorinostat demonstrated preclinical and clinical efficacy in human cancers and is the first histone deacetylase inhibitor (HDACi) approved for cancer treatment. Tissue transglutaminase (TG2) is a multifunctional enzyme that catalyzes a Ca2+ dependent transamidating reaction resulting in covalent cross-links between proteins. TG2 acts also as G-protein in trans-membrane signaling and as a cell surface adhesion mediator. TG2 up-regulation has been demonstrated in several cancers and its expression levels correlate with resistance to chemotherapy and metastatic potential. We demonstrated that the anti-proliferative effect of the HDACi vorinostat is paralleled by the induction of TG2 mRNA and protein expression in cancer cells but not in ex vivo treated peripheral blood lymphocytes. This effect was also shared by other pan-HDACi and resulted in increased TG2 transamidating activity. Notably, high TG2 basal levels in a panel of cancer cell lines correlated with lower vorinostat antiproliferative activity. Notably, in TG2-knockdown cancer cells vorinostat anti-proliferative and pro-apoptotic effects were enhanced, whereas in TG2-full-length transfected cells were impaired, suggesting that TG2 could represent a mechanism of intrinsic or acquired resistance to vorinostat. In fact, co-treatment of tumor cells with inhibitors of TG2 transamidating activity potentiated the antitumor effect of vorinostat. Moreover, vorinostat-resistant MCF7 cells selected by stepwise increasing concentrations of the drug, significantly overexpressed TG2 protein compared to parental cells, and co-treatment of these cells with TG2 inhibitors reversed vorinostat-resistance. Taken together, our data demonstrated that TG2 is involved in the resistance of cancer cells to vorinostat, as well as to other HDACi.

Synthesis of Arylpiperazine Derivatives as Protease Activated Receptor 1 Antagonists and Their Evaluation as Antiproliferative Agents.

BACKGROUND: Protease activated receptor-1 (PAR1) is a G-coupled receptor activated by α-thrombin and other proteases. Several reports have demonstrated the PAR1 involvement in tumorigenesis and tumor progression. In order to investigate on potential use of PAR1 antagonists as antiproliferative agents. AIMS: We have identified a series of arylpiperazine derivatives acting as PAR1 antagonists; the selected molecules have been evaluated for their antiproliferative properties. METHOD: All the compounds inhibited the growth of a panel of cell lines expressing PAR1; two of them, compounds 13 and 15, were able to inhibit, in a dose dependent manner, the growth of the selected cell lines with the lowest IC50 values, and were further characterized to define the mechanism responsible for the observed antiproliferative effect. RESULT: This study directed us to the identification of two interesting leads that may help to further validate PAR1 as an important therapeutic target for cancer treatment.

Phase II clinical study of valproic acid plus cisplatin and cetuximab in recurrent and/or metastatic squamous cell carcinoma of Head and Neck-V-CHANCE trial.

BACKGROUND: Recurrent/metastatic squamous cell carcinoma of the head and neck (SCCHN) has a poor prognosis and the combination of cisplatin and cetuximab, with or without 5-fluorouracil, is the gold standard treatment in this stage. Thus, the concomitant use of novel compounds represents a critical strategy to improve treatment results. Histone deacetylase inhibitors (HDACi) enhance the activity of several anticancer drugs including cisplatin and anti-Epidermal Growth Factor Receptor (anti-EGFR) compounds. Preclinical studies in models have shown that vorinostat is able to down regulate Epidermal Growth Factor Receptor (EGFR) expression and to revert epithelial to mesenchimal transition (EMT). Due to its histone deacetylase (HDAC) inhibiting activity and its safe use as a chronic therapy for epileptic disorders, valproic acid (VPA) has been considered a good candidate for anticancer therapy. A reasonable option may be to employ the combination of cisplatin, cetuximab and VPA in recurrent/metastatic SCCHN taking advantage of the possible positive interaction between histone deacetylase inhibitors, cisplatin and/or anti-EGFR. METHOD/DESIGN: V-CHANCE is a phase 2 clinical trial evaluating, in patients with recurrent/metastatic squamous cell carcinoma of the head and neck never treated with first-line chemotherapy, the concomitant standard administration of cisplatin (on day 1, every 3 weeks) and cetuximab (on day 1, weekly), in combination with oral VPA given daily from day -14 with a titration strategy in each patient (target serum level of 50-100 µg/ml). Primary end point is the objective response rate measured according to Response Evaluation Criteria in Solid Tumors (RECIST). Sample size, calculated according to Simon 2 stage minimax design will include 21 patients in the first stage with upper limit for rejection being 8 responses, and 39 patients in the second stage, with upper limit for rejection being 18 responses. Secondary endpoints are time to progression, duration of response, overall survival, safety. Objectives of the translational study are the evaluation on tumor samples of markers of treatment efficacy/resistance (i.e. γH2AX, p21/WAF, RAD51, XRCC1, EGFR, p-EGFR, Ki-67) and specific markers of VPA HDAC inhibitory activity (histones and proteins acetylation, Histone deacetylase isoforms) as well as valproate test, histones and proteins acetylation of peripheral blood mononuclear cell, tested on blood samples at baseline and at different time points during treatment. DISCUSSION: Overall, this study could provide a less toxic and more effective first-line chemotherapy regimen in patients with recurrent/metastatic squamous cell carcinoma of the head and neck by demonstrating the feasibility and efficacy of cisplatin/cetuximab plus valproic acid. Moreover, correlative studies could help to identify responder patients, and will add insights in the mechanism of the synergistic interaction between these agents. EUDRACT NUMBER: 2014-001523-69 TRIAL REGISTRATION: ClinicalTrials.gov number, NCT02624128.