Synergistic Antitumor Activity of ZD6474, An Inhibitor of Vascular Endothelial Growth Factor Receptor and Epidermal Growth Factor Receptor Signaling, with Gemcitabine and Ionizing Radiation against Pancreatic Cancer

Long non-coding RNAs and tyrosine kinase-mediated drug resistance in pancreatic cancer

Pancreatic cancer (PC) is one of the most malignant tumors with a dismal survival rate, this is primarily due to inevitable chemoresistance. Dysfunctional tyrosine kinases (TKs) and long non-coding RNAs (lncRNAs) affect the drug resistance and prognosis of PC. Here, we summarize the mechanisms by which TKs or lncRNAs mediate drug resistance and other malignant phenotypes. We also discuss that lncRNAs play oncogenic or tumor suppressor roles and different mechanisms including lncRNA-proteins/microRNAs to mediate drug resistance. Furthermore, we highlight that lncRNAs serve as upstream regulators of TKs mediating drug resistance. Finally, we display the clinical significance of TKs (AXL, EGFR, IGF1R, and MET), clinical trials, and lncRNAs (LINC00460, PVT1, HIF1A-AS1). In the future, TKs and lncRNAs may become diagnostic and prognostic biomarkers or drug targets to overcome the drug resistance of PC.

1,3,4-Oxadiazole and 1,3,4-Thiadiazole Nortopsentin Derivatives against Pancreatic Ductal Adenocarcinoma: Synthesis, Cytotoxic Activity, and Inhibition of CDK1

A new series of nortopsentin analogs, in which the central imidazole ring of the natural lead was replaced by a 1,3,4-oxadiazole or 1,3,4-thiadiazole moiety, was efficiently synthesized. The antiproliferative activity of all synthesized derivatives was evaluated against five pancreatic ductal adenocarcinoma (PDAC) cell lines, a primary culture and a gemcitabine-resistant variant. The five more potent compounds elicited EC₅₀ values in the submicromolar-micromolar range, associated with a significant reduction in cell migration. Moreover, flow cytometric analysis after propidium iodide staining revealed an increase in the G2-M and a decrease in G1-phase, indicating cell cycle arrest, while a specific ELISA demonstrated the inhibition of CDK1 activity, a crucial regulator of cell cycle progression and cancer cell proliferation.

Phosphoproteomics guides effective low-dose drug combinations against pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a limited set of known driver mutations but considerable cancer cell heterogeneity. Phosphoproteomics provides a readout of aberrant signaling and has the potential to identify new targets and guide treatment decisions. Using two-step sequential phosphopeptide enrichment, we generate a comprehensive phosphoproteome and proteome of nine PDAC cell lines, encompassing more than 20,000 phosphosites on 5,763 phospho-proteins, including 316 protein kinases. By using integrative inferred kinase activity (INKA) scoring, we identify multiple (parallel) activated kinases that are subsequently matched to kinase inhibitors. Compared with high-dose single-drug treatments, INKA-tailored low-dose 3-drug combinations against multiple targets demonstrate superior efficacy against PDAC cell lines, organoid cultures, and patient-derived xenografts. Overall, this approach is particularly more effective against the aggressive mesenchymal PDAC model compared with the epithelial model in both preclinical settings and may contribute to improved treatment outcomes in PDAC patients.

Network-based approach for targeting human kinases commonly associated with amyotrophic lateral sclerosis and cancer

Background

Amyotrophic Lateral Sclerosis (ALS) is a rare progressive and chronic motor neuron degenerative disease for which at present no cure is available. In recent years, multiple genes encode kinases and other causative agents for ALS have been identified. Kinases are enzymes that show pleiotropic nature and regulate different signal transduction processes and pathways. The dysregulation of kinase activity results in dramatic changes in processes and causes many other human diseases including cancers.

Methods

In this study, we have adopted a network-based system biology approach to investigate the kinase-based molecular interplay between ALS and other human disorders. A list of 62 ALS-associated-kinases was first identified and then we identified the disease associated with them by scanning multiple disease-gene interaction databases to understand the link between the ALS-associated kinases and other disorders.

Results

An interaction network with 36 kinases and 381 different disorders associated with them was prepared, which represents the complexity and the comorbidity associated with the kinases. Further, we have identified 5 miRNAs targeting the majority of the kinases in the disease-causing network. The gene ontology and pathways enrichment analysis of those miRNAs were performed to understand their biological and molecular functions along with to identify the important pathways. We also identified 3 drug molecules that can perturb the disease-causing network by drug repurposing.

Conclusion

This network-based study presented hereby contributes to a better knowledge of the molecular underpinning of comorbidities associated with the kinases associated with the ALS disease and provides the potential therapeutic targets to disrupt the highly complex disease-causing network.

Destabilizers of the thymidylate synthase homodimer accelerate its proteasomal degradation and inhibit cancer growth

Drugs that target human thymidylate synthase (hTS), a dimeric enzyme, are widely used in anticancer therapy. However, treatment with classical substrate-site-directed TS inhibitors induces over-expression of this protein and development of drug resistance. We thus pursued an alternative strategy that led us to the discovery of TS-dimer destabilizers. These compounds bind at the monomer-monomer interface and shift the dimerization equilibrium of both the recombinant and the intracellular protein toward the inactive monomers. A structural, spectroscopic, and kinetic investigation has provided evidence and quantitative information on the effects of the interaction of these small molecules with hTS. Focusing on the best among them, E7, we have shown that it inhibits hTS in cancer cells and accelerates its proteasomal degradation, thus causing a decrease in the enzyme intracellular level. E7 also showed a superior anticancer profile to fluorouracil in a mouse model of human pancreatic and ovarian cancer. Thus, over sixty years after the discovery of the first TS prodrug inhibitor, fluorouracil, E7 breaks the link between TS inhibition and enhanced expression in response, providing a strategy to fight drug-resistant cancers.

A New Oxadiazole-Based Topsentin Derivative Modulates Cyclin-Dependent Kinase 1 Expression and Exerts Cytotoxic Effects on Pancreatic Cancer Cells

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal form of cancer characterized by drug resistance, urging new therapeutic strategies. In recent years, protein kinases have emerged as promising pharmacological targets for the treatment of several solid and hematological tumors. Interestingly, cyclin-dependent kinase 1 (CDK1) is overexpressed in PDAC tissues and has been correlated to the aggressive nature of these tumors because of its key role in cell cycle progression and resistance to the induction of apoptosis. For these reasons, CDK1 is one of the main causes of chemoresistance, representing a promising pharmacological target. In this study, we report the synthesis of new 1,2,4-oxadiazole compounds and evaluate their ability to inhibit the cell growth of PATU-T, Hs766T, and HPAF-II cell lines and a primary PDAC cell culture (PDAC3). Compound 6b was the most active compound, with IC₅₀ values ranging from 5.7 to 10.7 µM. Molecular docking of 6b into the active site of CDK1 showed the ability of the compound to interact effectively with the adenosine triphosphate binding pocket. Therefore, we assessed its ability to induce apoptosis (which increased 1.5- and 2-fold in PATU-T and PDAC3 cells, respectively) and to inhibit CDK1 expression, which was reduced to 45% in Hs766T. Lastly, compound 6b passed the ADME prediction, showing good pharmacokinetic parameters. These data demonstrate that 6b displays cytotoxic activity, induces apoptosis, and targets CDK1, supporting further studies for the development of similar compounds against PDAC.

Dynamic Evaluation of Circulating miRNA Profile in EGFR-Mutated NSCLC Patients Treated with EGFR-TKIs

Background: Resistance to EGFR-TKIs constitutes a major challenge for the management of EGFR-mutated NSCLC, and recent evidence suggests that deregulation of specific microRNAs (miRNAs) may influence resistance to targeted agents. In this retrospective study, we explored the role of specific plasmatic miRNAs (miR-21, miR-27a and miR-181a) as a surrogate for predicting EGFR-TKI performance in EGFR-mutated NSCLC patients. Methods: Plasma samples of 39 advanced EGFR-mutated NSCLC patients treated with EGFR-TKIs were collected at different points in time and miRNA levels were assessed by RT-PCR. Results: Higher basal values of miR-21 were reported in patients who achieved a partial/complete response (PR/CR) compared to those with stability/progression of disease (SD/PD) (p = 0.011). Along the same line, patients who experienced a clinical benefit lasting at least six months displayed higher basal levels of circulating miR-21 (p = 0.039). However, dynamic evaluation of miRNA values after two months from the start of EGFR-TKI treatment showed that patients who experienced SD had an increase in miR-21 levels (Fold Change [FC] = 2.6) compared to patients achieving PR/CR (p = 0.029). The same tendency was observed for miR-27a (FC = 3.1) and miR-181a (FC = 2.0), although without reaching statistical significance. Remarkably, preclinical studies showed an increase in miR-21 levels in NSCLC cells that became resistant after exposure to EGFR-TKIs. Conclusions: Our study provides interesting insights on the role of circulating miRNAs, in particular miR-21, and their dynamic change over time in predicting EGFR-TKI response in EGFR-mutated NSCLC.

Methods to Study Posttranslational Modification Patterns in Cytotoxic T-Cells and Cancer

Protein posttranslational modifications (PTMs) regulate intracellular signaling associated with development and progression of many diseases; thus, they are key to understanding pathological mechanisms and set up more tailored therapies. In addition, many posttranslationally modified proteins are released into biological fluids and can be used as new and more specific biomarkers. Based on this evidence, we analyzed the role of some PTMs in cancer and described the correlation between specific PTMs and T-cells activation/inhibition in cancer microenvironment. In the second part of this chapter, we analyzed the most commonly used approaches for qualitative and quantitative determination of PTMs. The comparison of three distinct but often complementary methodologies such as immunoblotting, mass spectrometry, and ELISA assays has allowed to highlight the pros and cons of each approach with a focus on their current application and their future developments to obtain more confident biomarkers and therapeutic targets useful for diagnosis, prognosis, and monitoring of the response to therapy.

Targeting the Extra-Cellular Matrix-Tumor Cell Crosstalk for Anti-Cancer Therapy: Emerging Alternatives to Integrin Inhibitors

The extracellular matrix (ECM) is a complex network composed of a multitude of different macromolecules. ECM components typically provide a supportive structure to the tissue and engender positional information and crosstalk with neighboring cells in a dynamic reciprocal manner, thereby regulating tissue development and homeostasis. During tumor progression, tumor cells commonly modify and hijack the surrounding ECM to sustain anchorage-dependent growth and survival, guide migration, store pro-tumorigenic cell-derived molecules and present them to enhance receptor activation. Thereby, ECM potentially supports tumor progression at various steps from initiation, to local growth, invasion, and systemic dissemination and ECM-tumor cells interactions have long been considered promising targets for cancer therapy. Integrins represent key surface receptors for the tumor cell to sense and interact with the ECM. Yet, attempts to therapeutically impinge on these interactions using integrin inhibitors have failed to deliver anticipated results, and integrin inhibitors are still missing in the emerging arsenal of drugs for targeted therapies. This paradox situation should urge the field to reconsider the role of integrins in cancer and their targeting, but also to envisage alternative strategies. Here, we review the therapeutic targets implicated in tumor cell adhesion to the ECM, whose inhibitors are currently in clinical trials and may offer alternatives to integrin inhibition.

Novel thienopyrimidine derivatives as dual EGFR and VEGFR-2 inhibitors: design, synthesis, anticancer activity and effect on cell cycle profile

Aim: Design and synthesis of thienopyrimidine derivatives as dual EGFR and VEGFR-2 inhibitors.Material and methods: A series of novel 6,7,8,9-tetrahydro-5H-cyclohepta[4,5]thieno[2,3-d]pyrimidine derivatives with different substituents on C-4 position was synthesized and evaluated for their anticancer activity against MCF-7 cell line. EGFR, VEGFR-2 inhibitory assay, the cell cycle analysis and apoptosis induction ability of the most potent compound 5f were evaluated.Results: Most of the compounds showed moderate to significant anticancer activity. Compound 5f exhibited the most potent anticancer activity being 1.73- and 4.64-folds more potent than erlotinib and doxorubicin, respectively. Compound 5f showed potent EGFR inhibitory activity being 1.18-folds more potent than reference standard erlotinib and it also showed good VEGFR-2 inhibitory activity at the micromolar level with IC₅₀ value 1.23 µM. Compound 5f caused induction of cell cycle arrest at G2/M phase and accumulation of cells in pre-G1 phase. Compound 5f induced cellular apoptosis.

Vandetanib plus gemcitabine versus placebo plus gemcitabine in locally advanced or metastatic pancreatic carcinoma (ViP): a prospective, randomised, double-blind, multicentre phase 2 trial

BACKGROUND

Erlotinib is an EGFR tyrosine kinase inhibitor that has shown a significant but only marginally improved median overall survival when combined with gemcitabine in patients with locally advanced and metastatic pancreatic cancer. Vandetanib is a novel tyrosine kinase inhibitor of VEGFR2, RET, and EGFR, all of which are in involved in the pathogenesis of pancreatic cancer. We investigated the clinical efficacy of vandetanib when used in combination with gemcitabine in patients with advanced pancreatic cancer.

METHODS

The Vandetanib in Pancreatic Cancer (ViP) trial was a phase 2 double-blind, multicentre, randomised placebo-controlled trial in previously untreated adult patients (aged ≥18 years) diagnosed with locally advanced or metastatic carcinoma of the pancreas confirmed by cytology or histology. Patients had to have an Eastern Cooperative Oncology Group (ECOG) score of 0-2 and a documented life expectancy of at least 3 months. Patients were randomly assigned 1:1 to receive vandetanib plus gemcitabine (vandetanib group) or placebo plus gemcitabine (placebo group) according to pre-generated sequences produced on the principle of randomly permuted blocks with variable block sizes of two and four. Patients were stratified at randomisation by disease stage and ECOG performance status. All patients received gemcitabine 1000 mg/m2 as a 30-min intravenous infusion, weekly, for 7 weeks followed by a 1-week break, followed by a cycle of 3 weeks of treatment with a 1-week break, until disease progression, and either oral vandetanib 300 mg per day once daily or matching placebo. Patients and investigators were masked to treatment assignment. The primary outcome measure was overall survival (defined as the difference in time between randomisation and death from any cause or the censor date) in the intention-to-treat population. This trial has been completed and the final results are reported. The study is registered at EudraCT, number 2007-004299-38, and ISRCTN, number ISRCTN96397434.

FINDINGS

Patients were screened and enrolled between Oct 24, 2011, and Oct 7, 2013. Of 381 patients screened, 142 eligible patients were randomly assigned to treatment (72 to the vandetanib group and 70 to the placebo group). At database lock on July 15, 2015, at a median follow-up of 24·9 months (IQR 24·3 to not attainable), 131 patients had died: 70 (97%) of 72 in the vandetanib group and 61 (87%) of 70 in the placebo group. The median overall survival was 8·83 months (95% CI 7·11-11·58) in the vandetanib group and 8·95 months (6·55-11·74) in the placebo group (hazard ratio 1·21, 80·8% CI 0·95-1·53; log rank χ21df 1·1, p=0·303). The most common grade 3-4 adverse events were neutropenia (35 [49%] of 72 patients in the vandetanib group vs 22 [31%] of 70 in the placebo group), thrombocytopenia (20 [28%] vs 16 [23%]), hypertension (nine [13%] vs 11 [16%]), leucopenia (12 [17%] vs 13 [19%]), and fatigue (17 [24%] vs 15 [21%]). No treatment-related deaths occurred during the study.

INTERPRETATION

The addition of vandetanib to gemcitabine monotherapy did not improve overall survival in advanced pancreatic cancer. Tyrosine kinase inhibitors might still have potential in the treatment of pancreatic cancer but further development requires the identification of biomarkers to specifically identify responsive cancer subtypes.

FUNDING

Cancer Research UK and AstraZeneca.

Antibody-free detection of protein phosphorylation using intrinsic peroxidase-like activity of platinum/carbon dot hybrid nanoparticles

Platinum and carbon dot hybrid nanomaterials are prepared for visualized detection of phosphoproteins without the need for antibodies or enzymes. This new strategy can be used for colorimetric detection of phosphoproteins induced by protein kinase as well as protein phosphorylation sites on cell membranes.

Targeted therapies for pancreatic adenocarcinoma: Where do we stand, how far can we go?

Pancreatic adenocarcinoma (usually referred to as pancreatic cancer) is a highly lethal and aggressive malignancy with a disease-related mortality almost equaling its incidence, and one of the most challenging cancers to treat. The notorious resistance of pancreatic cancer not only to conventional cytotoxic therapies but also to almost all targeted agents developed to date, continues to puzzle the oncological community and represents one of the biggest hurdles to reducing the death toll from this ominous disease. This editorial highlights the most important recent advances in preclinical and clinical research, with regards to targeted therapeutics for pancreatic cancer, outlines current challenges and provides an overview of potential future perspectives in this rapidly evolving field.

A randomized, multicenter, phase II study of vandetanib monotherapy versus vandetanib in combination with gemcitabine versus gemcitabine plus placebo in subjects with advanced biliary tract cancer: the VanGogh study

BACKGROUND

The management of biliary tract cancers (BTCs) is complex due to limited data on the optimal therapeutic approach. This phase II multicenter study evaluated the efficacy and tolerability of vandetanib monotherapy compared with vandetanib plus gemcitabine or gemcitabine plus placebo in patients with advanced BTC.

PATIENTS AND METHODS

Patients were randomized in a 1 : 1 : 1 ratio to three treatment groups: vandetanib 300 mg monotherapy (V), vandetanib 100 mg plus gemcitabine (V/G), gemcitabine plus placebo (G/P). Vandetanib (300 mg or 100 mg) or placebo was given in single oral daily doses. Gemcitabine 1000 mg/m(2) was i.v. infused on day 1 and day 8 of each 21-day cycle. The primary end point was progression-free survival (PFS). Secondary end points were: objective response rate (ORR), disease control rate, overall survival, duration of response, performance status and safety outcomes.

RESULTS

A total of 173 patients (mean age 63.6 years) were recruited at 19 centers across Italy. Median (95% confidence intervals) PFS (days) were 105 (72-155), 114 (91-193) and 148 (71-225), respectively, for the V, V/G and G/P treatment groups, with no statistical difference among them (P = 0.18). No statistical difference between treatments was observed for secondary end points, except ORR, which slightly favored the V/G combination over other treatments. The proportion of patients reporting adverse events (AEs) was similar for the three groups (96.6% in V arm, 91.4% in the V/G arm and 89.3% in the G/P arm).

CONCLUSIONS

Vandetanib treatment did not improve PFS in patients with advanced BTC. The safety profile of vandetanib did not show any additional AEs or worsening of already known AEs.

CLINICAL TRIAL NUMBER

NCT00753675.

Neoadjuvant therapy for pancreas cancer: Past lessons and future therapies

Pancreatic adenocarcinoma remains a most deadly malignancy, with an overall 5-year survival of 5%. A subset of patients will be diagnosed with potentially resectable disease, and while complete surgical resection provides the only chance at cure, data from trials of postoperative chemoradiation and/or chemotherapy demonstrate a modest survival advantage over those patients who undergo resection alone. As such, most practitioners believe that completion of multimodality therapy is the optimal treatment. However, the sequence of surgery, chemotherapy and radiation therapy is frequently debated, as patients may benefit from a neoadjuvant approach by initiating chemotherapy and/or chemoradiation prior to resection. Here we review the rationale for neoadjuvant therapy, which includes a higher rate of completion of multimodality therapy, minimizing the risk of unnecessary surgical resection for patients who develop early metastatic disease, improved surgical outcomes and the potential for longer overall survival. However, there are no prospective, randomized studies of the neoadjuvant approach compared to a surgery-first strategy; the established and ongoing investigations of neoadjuvant therapy for pancreatic cancer are discussed in detail. Lastly, as the future of therapeutic regimens is likely to entail patient-specific genetic and molecular analyses, and the treatment that is best applied based on those data, a review of clinically relevant biomarkers in pancreatic cancer is also presented.

Synergy of enediyne antibiotic lidamycin and temozolomide in suppressing glioma growth with potentiated apoptosis induction

The present work evaluated the synergistic efficacy of an enediyne antibiotic lidamycin (LDM) plus temozolomide (TMZ) against glioma in vitro and in vivo. LDM plus TMZ inhibited the proliferations of rat glioma C6 cells and human glioma U87 cells more efficiently than the single usage of LDM or TMZ. In addition, LDM also potentiated the apoptosis inductions by TMZ in rat C6 cells and human U87 cells. Meanwhile, the results of TdT-mediated dUTP Nick End Labeling assay for subcutaneous U87 tumor sections indicated an enhanced apoptosis induction in vivo by LDM plus TMZ, which confirmed the high potency of the combination for glioma therapy. As determined by Western blot, apoptosis signal pathways in C6 cells and U87 cells were markedly affected by the synergistic alteration of P53, bax, procaspase 3, and bcd-2 expression. In both subcutaneous U87 xenograft and C6 intracerebral orthotopic implant model, TMZ-induced glioma growth suppression was dramatically potentiated by LDM. As shown, the combination therapy efficiently reduced the tumor volumes and tumor weights of the human glioma U87 xenograft. Kaplan-Meier assay revealed that LDM plus TMZ dramatically prolonged the life span of C6 intracerebral tumor-bearing rats with decreased tumor size. This study indicates that the combination of LDM with TMZ might be a promising strategy for glioma therapy.

Effects of pemetrexed, gefitinib, and their combination on human colorectal cancer cells

PURPOSE

The study investigated the effects of pemetrexed, gefitinib, and their combination on human colorectal cancer cells.

METHODS

Six human colorectal cancer cells were exposed to pemetrexed, gefitinib, and their combination. Antitumor effects were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Thymidylate synthase (TS) mRNA expression and EGFR mutation were studied by real-time RT-PCR and DNA sequence determination. Pharmacological interaction was studied using the combination index method. Cell cycle distribution and apoptosis were determined by flow cytometry. Activity assay was performed to assess the effects of drugs on TS activity, and Western blot was performed to assess the protein expression of pEGFR, pAKT, and pERK 1/2.

RESULTS

Six colorectal cancer cells are all sensitive to pemetrexed, and TS gene expression of cells was negatively related to pemetrexed sensitivity. The cytotoxic synergism was observed in concurrent pemetrexed combined with gefitinib and sequential pemetrexed followed by gefitinib. The combination of pemetrexed and gefitinib modulated cell cycle and induced apoptosis. Pemetrexed combined with gefitinib decreased TS mRNA expression and in situ activity. Pemetrexed induced an EGFR-mediated activation of the phosphatidylinositol 3-kinase/AKT and ERK pathway, which was inhibited by gefitinib.

CONCLUSIONS

Pemetrexed is a promising agent, and pemetrexed combined with gefitinib has a significantly synergistic effect on colorectal cancer cells, which seems to present a strategy of pemetrexed combined with EGFR-TKIs in colorectal cancer treatment.

Preclinical emergence of vandetanib as a potent antitumour agent in mesothelioma: molecular mechanisms underlying its synergistic interaction with pemetrexed and carboplatin

Background:

Although pemetrexed, a potent thymidylate synthase (TS) inhibitor, enhances the cytoytoxic effect of platinum compounds against malignant pleural mesothelioma (MPM), novel combinations with effective targeted therapies are warranted. To this end, the current study evaluates new targeted agents and their pharmacological interaction with carboplatin–pemetrexed in human MPM cell lines.

Methods:

We treated H2052, H2452, H28 and MSTO-211H cells with carboplatin, pemetrexed and targeted compounds (gefitinib, erlotinib, sorafenib, vandetanib, enzastaurin and ZM447439) and evaluated the modulation of pivotal pathways in drug activity and cancer cell proliferation.

Results:

Vandetanib emerged as the compound with the most potent cytotoxic activity, which interacted synergistically with carboplatin and pemetrexed. Drug combinations blocked Akt phosphorylation and increased apoptosis. Vandetanib significantly downregulated epidermal growth factor receptor (EGFR)/Erk/Akt phosphorylation as well as E2F-1 mRNA and TS mRNA/protein levels. Moreover, pemetrexed decreased Akt phosphorylation and expression of DNA repair genes. Finally, most MPM samples displayed detectable levels of EGFR and TS, the variability of which could be used for patients’ stratification in future trials with vandetanib–pemetrexed–carboplatin combination.

Conclusion:

Vandetanib markedly enhances pemetrexed–carboplatin activity against human MPM cells. Induction of apoptosis, modulation of EGFR/Akt/Erk phosphorylation and expression of key determinants for pemetrexed and carboplatin activity contribute to this synergistic interaction, and, together with the expression of these determinants in MPM samples, warrant further clinical investigation.

A phase 2 trial of gemcitabine, 5-fluorouracil, and radiation therapy in locally advanced nonmetastatic pancreatic adenocarcinoma : cancer and Leukemia Group B (CALGB) 80003

BACKGROUND

The purpose of this study was to assess the efficacy and safety of 5-fluorouracil (5FU) and gemcitabine administered concurrently with radiation in patients with locally advanced, nonmetastatic pancreatic cancer.

METHODS

Eligible patients had histologically confirmed pancreatic adenocarcinoma deemed locally unresectable without evidence of metastatic disease. In addition, all patients underwent laparoscopy or laparotomy before study entry to rule out peritoneal carcinomatosis. Patients received radiation therapy (50.4 Gy) with concurrent infusional 5FU (200 mg/m(2) 5 days/week) and weekly gemcitabine (200 mg/m(2) ). After a 3-week break, patients received weekly gemcitabine at 1000 mg/m(2) for 3 of 4 weeks, for 4 cycles. The primary endpoint of the trial was the proportion of patients surviving 9 months from study entry. Secondary endpoints included objective tumor response, CA19-9 response, overall survival (OS) time to progression (TTP), and toxicity.

RESULTS

Between November 2001 and October 2004, 81 patients were enrolled, 78 of whom were eligible for analysis. With a median follow-up of 55.2 months, the median OS was 12.2 months (95% confidence interval [CI], 10.9-14.9) and the median TTP was 10 months (95% CI, 6.4-12.0). An objective tumor response was seen in 19 patients (25%), and among 56 patients with an elevated CA19-9 at baseline, 29 (52%) had a sustained CA19-9 response. Overall, 41% of patients had grade 3 or greater treatment-related gastrointestinal adverse events.

CONCLUSIONS

The combination of 5FU, gemcitabine, and radiation is well tolerated. Survival is comparable with the best results of other recent studies of 5FU and radiation or gemcitabine and radiation.

Phosphorylation assay based on multifunctionalized soluble nanopolymer

Quantitative phosphorylation analysis is essential to understanding cellular signal transductions. Here we present a novel technology for the highly efficient assay of protein phosphorylation in high-throughput format without the use of phospho-specific antibodies. The technique is based on a water-soluble, nanosize polymer, termed pIMAGO, that is multifunctionalized with titanium(IV) ions for specific binding to phosphoproteins and with biotin groups that allow for enzyme-linked spectrometric detection. The sensitivity, specificity, and quantitative nature of pIMAGO for phosphorylation assays were examined with standard phosphoproteins and with purified phosphoproteins from whole cell extracts. As low as 100 pg of phosphoprotein can be measured quantitatively with the pIMAGO chemiluminescence assay. The pIMAGO assay was applied to an in vitro kinase assay, kinase inhibitor screening, and measurement of endogenous phosphorylation events. The technique provides a universal, quantitative method for global phosphorylation analysis with high sensitivity and specificity.

Vandetanib restores head and neck squamous cell carcinoma cells' sensitivity to cisplatin and radiation in vivo and in vitro

PURPOSE

We investigated whether vandetanib, an inhibitor of the tyrosine kinase activities of vascular endothelial growth factor receptor-2 (VEGFR-2), epidermal growth factor receptor (EGFR), and rearranged during transfection (RET), could augment the antitumor activity of radiation with or without cisplatin in preclinical in vitro and in vivo models of human head and neck squamous cell carcinoma (HNSCC).

EXPERIMENTAL DESIGN

OSC-19 and HN5 HNSCC cells that were cisplatin and radioresistant were treated with vandetanib, cisplatin, and radiation alone or in combination in vitro and in vivo using an orthotopic nude mouse model. Treatment effects were assessed using clonogenic survival assay, tumor volume, bioluminescence imaging, tumor growth delay, survival, microvessel density, tumor and endothelial cell apoptosis, and EGFR and Akt phosphorylation data.

RESULTS

Vandetanib plus cisplatin radiosensitized HNSCC cells in vitro and in vivo. The combination treatment with vandetanib, cisplatin, and radiation was superior to the rest of treatments (including the double combinations) in antitumoral effects, prolonging survival, decreasing cervical lymph node metastases in vivo. It also increased both tumor and tumor-associated endothelial cell apoptosis and decreased microvessel density in vivo. An analysis of tumor growth delay data revealed that vandetanib plus cisplatin enhanced radioresponse in vivo. All vandetanib-containing treatments inhibited EGFR and Akt phosphorylation in vitro and in vivo.

CONCLUSION

The addition of vandetanib to combination therapy with cisplatin and radiation was able to effectively overcome cisplatin and radioresistance in in vitro and in vivo models of HNSCC. Further study of this regimen in clinical trials may be warranted.

Identification of microRNA-21 as a biomarker for chemoresistance and clinical outcome following adjuvant therapy in resectable pancreatic cancer

Background

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis. The high risk of recurrence following surgical resection provides the rationale for adjuvant therapy. However, only a subset of patients benefit from adjuvant therapy. Identification of molecular markers to predict treatment outcome is therefore warranted. The aim of the present study was to evaluate whether expression of novel candidate biomarkers, including microRNAs, can predict clinical outcome in PDAC patients treated with adjuvant therapy.

Methodology/Principal Findings

Formalin-fixed paraffin embedded specimens from a cohort of 82 resected Korean PDAC cases were analyzed for protein expression by immunohistochemistry and for microRNA expression using quantitative Real-Time PCR. Cox proportional hazards model analysis in the subgroup of patients treated with adjuvant therapy (N = 52) showed that lower than median miR-21 expression was associated with a significantly lower hazard ratio (HR) for death (HR = 0.316; 95%CI = 0.166–0.600; P = 0.0004) and recurrence (HR = 0.521; 95%CI = 0.280–0.967; P = 0.04). MiR-21 expression status emerged as the single most predictive biomarker for treatment outcome among all 27 biological and 9 clinicopathological factors evaluated. No significant association was detected in patients not treated with adjuvant therapy. In an independent validation cohort of 45 frozen PDAC tissues from Italian cases, all treated with adjuvant therapy, lower than median miR-21 expression was confirmed to be correlated with longer overall as well as disease-free survival. Furthermore, transfection with anti-miR-21 enhanced the chemosensitivity of PDAC cells.

Conclusions Significance

Low miR-21 expression was associated with benefit from adjuvant treatment in two independent cohorts of PDAC cases, and anti-miR-21 increased anticancer drug activity in vitro. These data provide evidence that miR-21 may allow stratification for adjuvant therapy, and represents a new potential target for therapy in PDAC.

ZD6474, a multitargeted inhibitor for receptor tyrosine kinases, suppresses growth of gliomas expressing an epidermal growth factor receptor mutant, EGFRvIII, in the brain

Epidermal growth factor receptor (EGFR) vIII is a mutated EGFR that is frequently overexpressed in glioblastomas and implicated in response to receptor tyrosine kinase inhibitors. In this study, we investigate the effect of ZD6474 (ZACTIMA, vandetanib), a dual inhibitor for vascular endothelial growth factor receptor 2 and EGFR on growth and angiogenesis of gliomas expressing EGFRvIII. We used two glioma xenograft models, U87MG cells overexpressing EGFRvIII and short-term cultured primary glioma GBM8 cells with EGFRvIII. ZD6474 inhibited tumor growth and angiogenesis and induced cell apoptosis in various brain gliomas. Moreover, significant inhibition of EGFRvIII-expressing U87MG and GBM8 gliomas was observed compared with their controls. Magnetic resonance imaging analysis using the apparent diffusion coefficient and three-dimensional T2*weighed measurements validated ZD6474 inhibition on tumor growth and angiogenesis in EGFRvIII-expressing GBM8 gliomas. Mechanistically, ZD6474 shows better inhibition of cell growth and survival of U87MG/EGFRvIII, GBM6, and GBM8 cells that express EGFRvIII than U87MG or GBM14 cells that have nondetectable EGFRvIII through attenuation of activated phosphorylation of signal transducer and activator of transcription 3, Akt, and Bcl-X(L) expression. Albeit in lesser extent, ZD6474 also displays suppressions of U87MG/EGFR and GBM12 cells that overexpress wild-type EGFR. Additionally, ZD6474 inhibits activation of extracellular signal-regulated kinase 1/2 in both types of cells, and expression of a constitutively active phosphoinositide 3-kinases partially rescued ZD6474 inhibition in U87MG/EGFRvIII cells. Taken together, these data show that ZD6474 significantly inhibited growth and angiogenesis of gliomas expressing EGFRvIII by specifically blocking EGFRvIII-activated signaling mediators, suggesting a potential application of ZD6474 in treatments for glioblastomas that overexpress EGFRvIII. Mol Cancer Ther; 9(4); 929-41. (c)2010 AACR.

The effects of vandetanib on paclitaxel tumor distribution and antitumor activity in a xenograft model of human ovarian carcinoma

This study was designed to determine the effects of vandetanib, a small-molecule receptor tyrosine kinase inhibitor of vascular endothelial growth factor and epidermal growth factor receptor, on paclitaxel (PTX) tumor distribution and antitumor activity in xenograft models of human ovarian carcinoma. Nude mice bearing A2780-1A9 xenografts received daily (5, 10, or 15 days) doses of vandetanib (50 mg/kg per os), combined with PTX (20 mg/kg intravenously). Morphologic and functional modifications associated with the tumor vasculature (CD31 and alpha-smooth muscle actin staining and Hoechst 33342 perfusion) and PTX concentrations in plasma and tumor tissues were analyzed. Activity was evaluated as inhibition of tumor growth subcutaneously and spreading into the peritoneal cavity. Vandetanib treatment produced no significant change in tumor vessel density, although a reduced number of large vessels, an increased percentage of mature vessels, and diminished tumor perfusion were evident. Pretreatment with vandetanib led to decreased tumor PTX levels within 1 hour of PTX injection, although 24 hours later, tumor PTX levels were comparable with controls. In efficacy studies, the combination of vandetanib plus PTX improved antitumor activity compared with vandetanib or PTX alone, with greater effects being obtained when PTX was administered before vandetanib. The combination of PTX plus vandetanib reduced tumor burden in the peritoneal cavity of mice and significantly increased their survival. Analysis of vascular changes and PTX tumor uptake in vandetanib-treated tumors may help to guide the scheduling of vandetanib plus PTX combinations and may have implications for the design of clinical trials with these drugs.

Vandetanib (Zactima, ZD6474) antagonizes ABCC1- and ABCG2-mediated multidrug resistance by inhibition of their transport function

BACKGROUND

ABCC1 and ABCG2 are ubiquitous ATP-binding cassette transmembrane proteins that play an important role in multidrug resistance (MDR). In this study, we evaluated the possible interaction of vandetanib, an orally administered drug inhibiting multiple receptor tyrosine kinases, with ABCC1 and ABCG2 in vitro.

METHODOLOGY AND PRINCIPAL FINDINGS

MDR cancer cells overexpressing ABCC1 or ABCG2 and their sensitive parental cell lines were used. MTT assay showed that vandetanib had moderate and almost equal-potent anti-proliferative activity in both sensitive parental and MDR cancer cells. Concomitant treatment of MDR cells with vandetanib and specific inhibitors of ABCC1 or ABCG2 did not alter their sensitivity to the former drug. On the other hand, clinically attainable but non-toxic doses of vandetanib were found to significantly enhance the sensitivity of MDR cancer cells to ABCC1 or ABCG2 substrate antitumor drugs. Flow cytometric analysis showed that vandetanib treatment significantly increase the intracellular accumulation of doxorubicin and rhodamine 123, substrates of ABCC1 and ABCG2 respectively, in a dose-dependent manner (P<0.05). However, no significant effect was shown in sensitive parental cell lines. Reverse transcription-PCR and Western blot analysis showed that vandetanib did not change the expression of ABCC1 and ABCG2 at both mRNA and protein levels. Furthermore, total and phosphorylated forms of AKT and ERK1/2 remained unchanged after vandetanib treatment in both sensitive and MDR cancer cells.

CONCLUSIONS

Vandetanib is unlikely to be a substrate of ABCC1 or ABCG2. It overcomes ABCC1- and ABCG2-mediated drug resistance by inhibiting the transporter activity, independent of the blockade of AKT and ERK1/2 signal transduction pathways.

Improving gemcitabine-mediated radiosensitization using molecularly targeted therapy: a review

In the last three decades, gemcitabine has progressed from the status of a laboratory cytotoxic drug to a standard clinical chemotherapeutic agent and a potent radiation sensitizer. In an effort to improve the efficacy of gemcitabine, additional chemotherapeutic agents have been combined with gemcitabine (both with and without radiation) but with toxicity proving to be a major limitation. Therefore, the integration of molecularly targeted agents, which potentially produce less toxicity than standard chemotherapy, with gemcitabine radiation is a promising strategy for improving chemoradiation. Two of the most promising targets, described in this review, for improving the efficacy of gemcitabine radiation are epidermal growth factor receptor and checkpoint kinase 1.

Matuzumab short-term therapy in experimental pancreatic cancer: prolonged antitumor activity in combination with gemcitabine

PURPOSE

The epidermal growth factor receptor ErbB-1 is commonly expressed in pancreatic cancer and ErbB-1 targeting has shown promising results. We wanted to evaluate matuzumab (EMD72000), a fully humanized ErbB-1-specific monoclonal antibody in combination with gemcitabine in experimental pancreatic cancer.

EXPERIMENTAL DESIGN

Using the human pancreatic cancer cell line L3.6pl, we investigated matuzumab in vitro and in vivo. ErbB-1 phosphorylation and downstream pathway activation were evaluated by Western blot. Proliferation and migration assays and fluorescence-activated cell sorting analysis were done. For in vivo studies, we used an orthotopic nude mice model in which 40 mg/kg of matuzumab+/-100 mg/kg of gemcitabine were administered twice weekly. Different treatment durations (7, 14, 21, and 25 days) and varying time points of treatment initiation (days 8, 15, 22, and 29) were evaluated. Ki67, CD31, and phosphorylated p44/42 mitogen-activated protein kinase (MAPK) immunohistochemistry were done.

RESULTS

ErbB-1 phosphorylation and downstream MAPK and AKT signaling were significantly reduced by matuzumab. Matuzumab significantly inhibited proliferation and migration in vitro, and induced tumor cell apoptosis in a dose-dependant manner. Matuzumab therapy significantly lowered tumor volume in vivo, reduced lymph node and liver metastases, and decreased microvessel density and tumor cell proliferation. These effects were significantly enhanced when gemcitabine was added. A significant and prolonged antitumor activity was even evident with short-term therapy (7 days) and with a late onset of therapy (day 22 after tumor cell injection).

CONCLUSIONS

Matuzumab is an effective agent with long-lasting antiproliferative, proapoptotic, antiangiogenic, and antimetastatic activity in human pancreatic cancer models. These effects might be potentiated by gemcitabine.

Pancreatic cancer: from molecular pathogenesis to targeted therapy

Pancreatic cancer is a deadly malignancy with still high mortality and poor survival despite the significant advances in understanding, diagnosis, and access to conventional and novel treatments. Though cytotoxic chemotherapy based on the purine analogue gemcitabine remains the standard approach in adjuvant and palliative setting the need for novel agents aiming at the main pathophysiological abnormalities and molecular pathways involved remains soaring. So far, evidence of clinical benefit, though small, exists only from the addition of the targeted agent erlotinib on the standard gemcitabine chemotherapy. Apart from the popular monoclonal antibodies and small molecules tyrosine kinase inhibitors, other novel compounds being tested in preclinical and clinical studies target mTOR, NF-kappaB, proteasome and histone deacetylase. These new drugs along with gene therapy and immunotherapy, which are also under clinical evaluation, may alter the unfavorable natural course of this disease. In this review we present the main pathophysiological alterations met in pancreatic cancer and the results of the florid preclinical and clinical research with regards to the targeted therapy associated to these abnormalities.

Molecular targeted therapies for pancreatic cancer

BACKGROUND

Pancreatic cancer cells express different mutations that increase the aggressiveness and confer resistance to conventional chemotherapy and radiotherapy. Molecules that selectively bind and inhibit these mutations are effective in other solid tumors and are now emerging as a complementary therapy in pancreatic cancer. The objective of this review is to describe the effect of drugs that inhibit specific mutations present in pancreatic cancer with special emphasis on clinical trials.

DATA SOURCES

We reviewed the English-language literature (MedLine) addressing the role of drugs that target mutations present in pancreatic cancer. Both preclinical and clinical studies were included.

CONCLUSIONS

Preclinical evidence supports the combination of conventional approved therapies plus drugs that block epidermal growth factor receptor and vascular growth endothelial factor or induce apoptosis. However, most of the current clinical evidence is limited to small phase I trials evaluating the toxicity and safety of these regimens. The results of additional randomized trials that are still undergoing will clarify the role of these drugs in pancreatic cancer.

Pharmacokinetic-directed dosing of vandetanib and docetaxel in a mouse model of human squamous cell carcinoma

Docetaxel, usually administered according to maximum tolerated dose (MTD), can inhibit endothelial cell proliferation at low nanomolar concentrations. Docetaxel may exert antiangiogenic effects if dosed so plasma levels are maintained at low nanomolar concentrations over a prolonged time. We evaluated metronomic and MTD-based dosing of docetaxel with and without vandetanib, a vascular endothelial growth factor receptor-2 and epidermal growth factor receptor tyrosine kinase inhibitor with antiangiogenic and antitumor activity, in a head and neck xenograft model. A murine physiologically based pharmacokinetic model was modified to predict docetaxel distribution following i.p. administration to design dosing regimens that target prespecified plasma concentrations, for antiendothelial effects (metronomic), or exposure, to mimic 30 mg/m2 (weekly/MTD) docetaxel in humans. Animals were treated for 28 days with 1 mg/kg/d (DTX1) or 6 mg/kg q4d (DTX6) docetaxel with or without vandetanib (15 mg/kg/d p.o.) in mice bearing UMSCC2 tumor xenografts. The DTX1 dosing scheme was adjusted to treatment for 10 days followed by 9 days off due to severe gastrointestinal toxicity. All treatment groups significantly reduced tumor volume, tumor proliferation (Ki-67), and tumor endothelial cell proliferation (Ki-67/von Willebrand factor) compared with control. Addition of vandetanib to docetaxel treatment significantly enhanced tumor growth inhibition over single-agent therapy. A positive correlation of tumor endothelial cell proliferation with tumor growth rates demonstrates vandetanib and docetaxel antiangiogenic effects. Due to the morbidity observed with DTX1 treatment, it is difficult to clearly ascertain if metronomic schedules will be effective for treatment. Docetaxel with vandetanib is effective in treating UMSCC2 xenografts at concentrations relevant to exposures in humans.

Biological approaches to therapy of pancreatic cancer

Pancreatic cancer is a lethal disease and notoriously difficult to treat. Only a small proportion is curative by surgical resection, whilst standard chemotherapy for patients with advanced disease has only modest effect with substantial toxicity. Clearly there is a need for the continual development of novel therapeutic agents to improve the current situation. Improvement of our understanding of the disease has generated a large number of studies on biological approaches targeting the molecular abnormalities of pancreatic cancer, including gene therapy and signal transduction inhibition, antiangiogenic and matrix metalloproteinase inhibition, oncolytic viral therapy and immunotherapy. This article provides a review of these approaches, both investigated in the laboratories and in subsequent clinical trials.

EGFR and VEGFR as potential target for biological therapies in HCC cells

Hepatocellular carcinoma (HCC) is a highly malignant cancer with poor prognosis. Inhibitors of EGFR and VEGFR for HCC treatment are currently under investigation. Gefitinib and vandetanib inhibit migration of HCC cells on Laminin-5 and Fibronectin, and invasion through matrigel. Both drugs inhibit p-EGFR after short time, while their efficacy on p-Erk1/2 and p-Akt is progressive and stable over time. PI3K/Akt and MEK/Erk1/2 inhibitors, inhibit migration and invasion as well as inducing de-phosphorylation of downstream effectors. Finally, both inhibitors, vandetanib and gefitinib down-regulated the secretion of matrix metalloproteases MMP-2 and MMP-9. All these biological effects seem to depend on the activity of gefitinib and vandetanib blocking activity towards p-EGFR mediated pathways.

Molecular mechanisms underlying the synergistic interaction of erlotinib, an epidermal growth factor receptor tyrosine kinase inhibitor, with the multitargeted antifolate pemetrexed in non-small-cell lung cancer cells

Because the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor erlotinib and the multitargeted antifolate pemetrexed are registered in the treatment of second-line non-small-cell lung cancer (NSCLC), empirical combinations of these drugs are being tested. This study investigated molecular mechanisms underlying their combination in six NSCLC cell lines. Cells were characterized by heterogeneous expression of pemetrexed determinants, including thymidylate synthase (TS) and dihydrofolate reductase (DHFR), and mutations potentially affecting chemosensitivity. Pharmacological interaction was studied using the combination index (CI) method, whereas cell cycle, apoptosis induction, and EGFR, extracellular signal-regulated kinases 1 and 2, and Akt phosphorylation were studied by flow cytometry, fluorescence microscopy, and enzyme-linked immunosorbent assays. Reverse-transcriptase polymerase chain reaction (RT-PCR), Western blot, and activity assays were performed to assess whether erlotinib influenced TS. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium assays demonstrated that EGFR and k-Ras mutations were related to erlotinib sensitivity, whereas TS and DHFR expression were related to pemetrexed sensitivity. Synergistic cytotoxicity was found in all cells, most pronounced with pemetrexed + erlotinib (24 h) --> erlotinib (48 h) sequence (CI, 0.09-0.40), which was associated with a significant induction of apoptosis. Pemetrexed increased EGFR phosphorylation and reduced Akt phosphorylation, which was additionally reduced by drug combination (-70.6% in H1650). Erlotinib significantly reduced TS expression and activity, possibly via E2F-1 reduction, as detected by RT-PCR and Western blot, and the combination decreased TS in situ activity in all cells. Erlotinib and pemetrexed showed a strong synergism in NSCLC cells, regardless of their genetic characteristics. Induction of apoptosis, modulation of EGFR and Akt phosphorylation, and changes in the expression of critical genes involved in pemetrexed activity contribute to this synergistic interaction and support the clinical investigation of these markers.

Targeting vascular endothelial growth factor (VEGF)-receptor-signaling in renal cell carcinoma

Metastatic renal cell carcinoma (RCC) is resistant to conventional chemotherapy. Combined data for a variety of immunotherapies resulted in an overall chance of partial (PR) or complete remission (CR) of only 12.9%. There is a clear need for novel, more effective therapies to prevent relapse, control metastases and improve overall survival. Improved understanding of RCC disease biology has led to the introduction of molecularly targeted treatment strategies in these cancers. Von Hippel-Lindau (VHL) gene inactivation is observed in most clear cell renal carcinoma, resulting in vascular endothelial growth factor (VEGF) over-expression and driving the malignant phenotype. This review discusses the efficacy of novel therapies targeting the VEGF receptor (VEGFR) (e.g. anti-VEGF antibodies, VEGFR tyrosine kinase inhibitors, mTOR inhibitors), some of which were recently approved by the Food and Drug Administration/European Medicines Evaluation Agency (FDA/EMEA) and represent the new treatment standards in RCC patients.