Geny Piro

HDAC inhibitor vorinostat enhances the antitumor effect of gefitinib in squamous cell carcinoma of head and neck by modulating ErbB receptor expression and reverting EMT.

Potentiation of epidermal growth factor receptor (EGFR) inhibitors is required in squamous cell carcinoma of head and neck (SCCHN) to improve their therapeutic index. We demonstrated that the histone deacetylase inhibitor vorinostat in combination with the EGFR tyrosine kinase inhibitor gefitinib induced synergistic inhibition of proliferation, migration, and invasion as well as induction of apoptosis in SCCHN cells, including cells resistant to gefitinib. We provided evidence suggesting that differential modulation of ErbB receptors together with reversion of epithelial‐to‐mesenchymal transition (EMT) by vorinostat represent mechanistic bases for the observed synergism. We demonstrated in epithelial CAL27 cells expressing EGFR, ErbB2, and ErbB3 that vorinostat downregulated the expression and signaling of all three receptors. In gefitinib‐resistant KB and Hep‐2 cells, both of which had undergone EMT and expressed very low levels of ErbB3, vorinostat reverted the mesenchymal phenotype by inducing both E‐cadherin and ErbB3 and downregulating vimentin as well as EGFR and ErbB2. Both transcriptional and post‐translational mechanisms were involved in the modulation of ErbB receptors by vorinostat. Attenuation of all ErbB transcripts in CAL27 cells as well as induction of ErbB3 transcript in Hep‐2 and KB cells was seen upon vorinostat treatment. We showed that vorinostat induced ubiquitination of EGFR and ErbB2 and targeted them predominantly to lysosome‐degradation in all cell lines, while the induction of ErbB3‐ubiquitination in CAL27 cells led to proteasomes‐degradation. Overall, this study suggests that the vorinostat/gefitinib combination represents a promising therapeutic strategy that warrants further clinical evaluation in SCCHN, including tumors intrinsically resistant to EGFR‐inhibitors. J. Cell. Physiol. 226: 2378–2390, 2011.

Mechanisms of resistance to chemotherapeutic and anti-angiogenic drugs as novel targets for pancreatic cancer therapy

Pancreatic cancer remains one of the most lethal and poorly understood human malignancies and will continue to be a major unsolved health problem in the 21st century. Despite efforts over the past three decades to improve diagnosis and treatment, the prognosis for patients with pancreatic cancer is extremely poor with or without treatment, and incidence rates are virtually identical to mortality rates. Although advances have been made through the identification of relevant molecular pathways in pancreatic cancer, there is still a critical, unmet need for the translation of these findings into effective therapeutic strategies that could reduce the intrinsic drug resistance of this disease and for the integration of these molecularly targeted agents into established combination chemotherapy and radiotherapy regimens in order to improve patients’ survival. Tumors are heterogeneous cellular entities whose growth and progression depend on reciprocal interactions between genetically altered neoplastic cells and a non-neoplastic microenvironment. To date, most of the mechanisms of resistance studied have been related to tumor cell-autonomous signaling pathways. However, recent data suggest a putative important role of tumor microenvironment in the development and maintenance of resistance to classic chemotherapeutic and targeted therapies. This present review is meant to describe and discuss some of the most important advances in the comprehension of the tumor cell-autonomous and tumor microenvironment-related molecular mechanisms responsible for the resistance of pancreatic cancer to the proapoptotic activity of the classic chemotherapeutic agents and to the most novel anti-angiogenic drugs. We present some of the emerging therapeutic targets for the modulation of this resistant phenotype.

Acquired resistance to zoledronic acid and the parallel acquisition of an aggressive phenotype are mediated by p38-MAP kinase activation in prostate cancer cells

The nitrogen-containing bisphosphonates (N-BP) zoledronic acid (ZOL) inhibits osteoclast-mediated bone resorption, and it is used to prevent skeletal complications from bone metastases. ZOL has also demonstrated anticancer activities in preclinical models and, recently, in cancer patients, highlighting the interest in determining eventual mechanisms of resistance against this agent. In our study, we selected and characterised a resistant subline of prostate cancer (PCa) cells to better understand the mechanisms, by which tumour cells can escape the antitumour effect of ZOL. DU145R80-resistant cells were selected in about 5 months using stepwise increasing concentrations of ZOL from DU145 parental cells. DU145R80 cells showed a resistance index value of 5.5 and cross-resistance to another N-BP, pamidronate, but not to the non-nitrogen containing BP clodronate. Notably, compared with DU145 parental cells, DU145R80 developed resistance to apoptosis and anoikis, as well as overexpressed the anti-apoptotic protein Bcl-2 and oncoprotein c-Myc. Moreover, DU145R80 cells underwent epithelial to mesenchymal transition (EMT) and showed increased expression of the metalloproteases MMP-2/9, as well as increased invading capability. Interestingly, compared with DU145, DU145R80 cells also increased the gene expression and protein secretion of VEGF and the cytokines Eotaxin-1 and IL-12. At the molecular level, DU145R80 cells showed strong activation of the p38-MAPK-dependent survival pathway compared with parental sensitive cells. Moreover, using the p38-inhibitor SB203580, we completely reversed the resistance to ZOL, as well as EMT marker expression and invasion. Furthermore, SB203580 treatment reduced the expression of VEGF, Eotaxin-1, IL-12, MMP-9, Bcl-2 and c-Myc. Thus, for the first time, we demonstrate that the p38-MAPK pathway can be activated under continuous extensive exposure to ZOL in PCa cells and that the p38-MAPK pathway has a critical role in the induction of resistance, as well as in the acquisition of a more aggressive and invasive phenotype.

Vorinostat synergises with capecitabine through upregulation of thymidine phosphorylase.

Background:Potentiation of anticancer activity of capecitabine is required to improve its therapeutic index. In colorectal cancer (CRC) cells, we evaluated whether the histone deacetylase-inhibitor vorinostat may induce synergistic antitumour effects in combination with capecitabine by modulating the expression of thymidine phosphorylase (TP), a key enzyme in the conversion of capecitabine to 5-florouracil (5-FU), and thymidylate synthase (TS), the target of 5-FU.Methods:Expression of TP and TS was measured by real-time PCR, western blotting and immunohistochemistry. Knockdown of TP was performed by specific small interfering RNA. Antitumour activity of vorinostat was assessed in vitro in combination with the capecitabine active metabolite deoxy-5-fluorouridine (5′-DFUR) according to the Chou and Talay method and by evaluating apoptosis as well as in xenografts-bearing nude mice in combination with capecitabine.Results:Vorinostat induced both in vitro and in vivo upregulation of TP as well as downregulation of TS in cancer cells, but not in ex vivo treated peripheral blood lymphocytes. Combined treatment with vorinostat and 5′-DFUR resulted in a synergistic antiproliferative effect and increased apoptotic cell death in vitro. This latter effect was impaired in cells where TP was knocked. In vivo, vorinostat plus capecitabine potently inhibited tumour growth, increased apoptosis and prolonged survival compared with control or single-agent treatments.Conclusions:Overall, this study suggests that the combination of vorinostat and capecitabine is an innovative antitumour strategy and warrants further clinical evaluation for the treatment of CRC.

An FGFR3 autocrine loop sustains acquired resistance to trastuzumab in gastric cancer patients

Purpose: The majority of gastric cancer patients who achieve an initial response to trastuzumab-based regimens develop resistance within 1 year of treatment. This study was aimed at identifying the molecular mechanisms responsible for resistance. Experimental Design: A HER2+-trastuzumab sensitive NCI-N87 gastric cancer orthotopic nude mouse model was treated with trastuzumab until resistance emerged. Differentially expressed transcripts between trastuzumab-resistant and sensitive gastric cancer cell lines were annotated for functional interrelatedness by Ingenuity Pathway Analysis software. Immunohistochemical analyses were performed in pretreatment versus posttreatment biopsies from gastric cancer patients receiving trastuzumab-based treatments. All statistical tests were two-sided. Results: Four NCI-N87 trastuzumab-resistant (N87-TR) cell lines were established. Microarray analysis showed HER2 downregulation, induction of epithelial-to-mesenchymal transition, and indicated fibroblast growth factor receptor 3 (FGFR3) as one of the top upregulated genes in N87-TR cell lines. In vitro, N87-TR cell lines demonstrated a higher sensitivity than did trastuzumab-sensitive parental cells to the FGFR3 inhibitor dovitinib, which reduced expression of pAKT, ZEB1, and cell migration. Oral dovitinib significantly (P = 0.0006) reduced tumor burden and prolonged mice survival duration in N87-TR mouse models. A higher expression of FGFR3, phosphorylated AKT, and ZEB1 were observed in biopsies from patients progressing under trastuzumab-based therapies if compared with matched pretreatment biopsies. Conclusions: This study identified the FGFR3/AKT axis as an escape pathway responsible for trastuzumab resistance in gastric cancer, thus indicating the inhibition of FGFR3 as a potential strategy to modulate this resistance. Clin Cancer Res; 22(24); 6164–75. ©2016 AACR.

Rationale and clinical use of multitargeting anticancer agents

Human solid tumors contain genetically distinct subpopulations of tumor cells that can be enriched under selective pressure of specific treatments. This heterogeneous nature reflects the dynamism of drug response and it represents a fundamental driver of resistance. Moreover, the complexity of cancer disease is increased by the activity of cross-talking, redundant signaling pathways, escape pathways and compensatory events, which triggers activation of secondary growth and survival. Broad multi-targeted approaches are requested to overcome a complex, heterogeneous, and dynamic disease such as cancer.

Combined inhibition of IL1, CXCR1/2, and TGFβ signaling pathways modulates in-vivo resistance to anti-VEGF treatment.

Resistance of tumors to antiangiogenic therapies is becoming increasingly relevant. We recently identified interleukin-1 (IL1), CXC receptors (CXCR)1/2 ligands, and transforming growth factor &bgr; (TGF&bgr;) among the proinflammatory factors that were expressed at higher levels in murine models resistant to the antivascular endothelial growth factor (anti-VEGF) antibody bevacizumab. Here, we hypothesized that the combined inhibition of these proinflammatory signaling pathways might reverse this anti-VEGF resistance. Bevacizumab-resistant FGBR pancreatic cancer cells were treated in vitro with bevacizumab, the recombinant human IL1 receptor antagonist anakinra, the monoclonal antibody against TGF&bgr; receptor type II TR1, and a novel recombinant antibody binding CXCR1/2 ligands. The FGBR cells treated with these agents in combination had significantly higher levels of E-cadherin and lower levels of vimentin, IL6, phosphorylated p65, and SMAD2, and showed significantly lower migration rates than did their controls treated with the same agents without bevacizumab or with a single agent bevacizumab as a control. Consistently, the combination of these agents with bevacizumab reduced the FGBR tumor burden and significantly prolonged mice survival compared with bevacizumab in monotherapy. Tumors from mice receiving the combination treatment showed significantly lower expression of IL6 and phosphorylated SMAD2, higher expression of E-cadherin and lower levels of vimentin, and a significantly lower infiltration by CD11b+ cells compared with bevacizumab-treated controls. This study suggests that inhibition of IL1, CXCR1/2, and TGF&bgr; signaling pathways is a potential therapeutic approach to modulate the acquired resistance to anti-VEGF treatment by reversing epithelial–mesenchymal transition and inhibiting CD11b+ proangiogenic myeloid cells’ tumor infiltration.

TAK1-regulated expression of BIRC3 predicts resistance to preoperative chemoradiotherapy in oesophageal adenocarcinoma patients

Background:About 20% of resectable oesophageal carcinoma is resistant to preoperative chemoradiotherapy. Here we hypothesised that the expression of the antiapoptotic gene Baculoviral inhibitor of apoptosis repeat containing (BIRC)3 induced by the transforming growth factor β activated kinase 1 (TAK1) might be responsible for the resistance to the proapoptotic effect of chemoradiotherapy in oesophageal carcinoma.Methods:TAK1 kinase activity was inhibited in FLO-1 and KYAE-1 oesophageal adenocarcinoma cells using (5Z)-7-oxozeaenol. The BIRC3 mRNA expression was measured by qRT–PCR in 65 pretreatment frozen biopsies from patients receiving preoperatively docetaxel, cisplatin, 5-fluorouracil, and concurrent radiotherapy. Receiver operator characteristic (ROC) analyses were performed to determine the performance of BIRC3 expression levels in distinguishing patients with sensitive or resistant carcinoma.Results:In vitro, (5Z)-7-oxozeaenol significantly reduced BIRC3 expression in FLO-1 and KYAE-1 cells. Exposure to chemotherapeutic agents or radiotherapy plus (5Z)-7-oxozeaenol resulted in a strong synergistic antiapoptotic effect. In patients, median expression of BIRC3 was significantly (P<0.0001) higher in adenocarcinoma than in the more sensitive squamous cell carcinoma subtype. The BIRC3 expression significantly discriminated patients with sensitive or resistant adenocarcinoma (AUC-ROC=0.7773 and 0.8074 by size-based pathological response or Mandards tumour regression grade classifications, respectively).Conclusions:The BIRC3 expression might be a valid biomarker for predicting patients with oesophageal adenocarcinoma that could most likely benefit from preoperative chemoradiotherapy.

A circulating TH2 cytokines profile predicts survival in patients with resectable pancreatic adenocarcinoma

ABSTRACT Surgery is the only potentially curative option for patients with pancreatic ductal adenocarcinoma (PDAC), but metastatic relapse remains common. We hypothesized that the expression levels of inflammatory cytokines could predict recurrence of PDAC, thus allowing to select patients who most likely could benefit from surgical resection. We prospectively collected plasma at diagnosis from 287 patients with pancreatic resectable neoplasms. The expression levels of 23 cytokines were measured in 90 patients with PDAC by using a multiplex analyte profiling assay. Levels higher than cutoff identified of the TH2 cytokines interleukin (IL)4, IL5, IL6 of macrophage inflammatory protein (MIP)1α, granulocyte-macrophage colony-stimulating factor (GM-CSF), and monocyte chemoattractant protein (MCP)1, and of IL17α, IFNγ-induced protein (IP)10, and IL1b were significantly associated with a shorter median OS. In particular, levels of IL4 and IP10 higher than cutoff identified, and level of TH1 cytokines TNFα and INFγ, and of IL9 and IL1Rα lower than cutoff identified were significantly associated with a shorter DFS. In the multivariate analysis, high IP10 was confirmed as negatively associated with OS (HR = 3.097, p = 0.014) and IL4 and TNFα remain negatively (HR = 2.75, p = 0.002) and positively (HR = 0.224, p = 0.049) associated with DFS, respectively. Simultaneous expression of low IL4 and high TNFα identified patients with best prognosis (HR = 0.313, p < 0.0001). In conclusion, we demonstrated that, among a series of cytokines, IL4 is the most significant independent prognostic factor for DFS in resectable PDAC patients, and it could be useful to select patients with high risk of early recurrence who may avoid an unnecessary resection.

Homeobox B9 mediates resistance to anti-VEGF therapy in colorectal cancer patients

Purpose: The identification of predictive biomarkers for antiangiogenic therapies remains an unmeet need. We hypothesized that the transcription factor Homeobox B9 (HOXB9) could be responsible for the tumor resistance to the anti-VEGF agent bevacizumab. Experimental Design: HOXB9 expression and activation were measured in eight models of colorectal and pancreatic cancer with different resistance to bevacizumab. Serum levels of Angiopoietin-like Protein (Angptl)2, CXC receptor ligand (CXCL)1, IL8, and TGFβ1 in tumor-bearing mice were measured by multiplex xMAP technology. HOXB9 expression was measured by immunohistochemical analysis in 81 pretreatment specimens from metastatic colorectal cancer patients. Differences in progression-free survival (PFS) were determined using a log-rank test. Results: HOXB9-positive tumors were resistant to bevacizumab, whereas mice bearing HOXB9-negative tumors were cured by this agent. Silencing HOXB9 in bevacizumab-resistant models significantly (P < 0.05) reduced Angptl2, CXCL1, IL8, and TGFβ1 levels, reverted their mesenchymal phenotype, reduced CD11b+ cells infiltration, and restored, in turn, sensitivity to bevacizumab. HOXB9 had no prognostic value in patients treated with a first-line chemotherapeutic regimen noncontaining bevacizumab. However, patients affected by an HOXB9-negative tumor had a significantly longer PFS compared with those with an HOXB9-positive tumor if treated with a first-line regimen containing bevacizumab (18.0 months vs. 10.4 months; HR 2.037; 95% confidence interval, 1.006–4.125; P = 0.048). Conclusions: These findings integrate the complexity of numerous mechanisms of anti-VEGF resistance into the single transcription factor HOXB9. Silencing HOXB9 could be a promising approach to modulate this resistance. Our results candidate HOXB9 as predictive biomarker for selecting colorectal cancer patients for antiangiogenic therapy. Clin Cancer Res; 23(15); 4312–22. ©2017 AACR.