Antiangiogenic and antitumor activity of a novel vascular endothelial growth factor receptor-2 tyrosine kinase inhibitor ZD6474 in a metastatic human pancreatic tumor model

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.

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.

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.

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.

Alteration in the balance of prosurvival and proapoptotic signalling pathways leads to sequence-dependent synergism between docetaxel and sorafenib in human non-small cell lung cancer cell lines

To examine the antiproliferative effect of the combination of docetaxel and sorafenib, applied to the representative non-small cell lung cancer cell line A549 cells either wild type or with acquired resistance to docetaxel (A549/D). The aim of this study is to evaluate the synergistic effect of combination treatment on cell growth inhibition and to elucidate the involved molecular mechanisms. A549 cells with acquired resistance to docetaxel were established by continuous exposure to docetaxel. We examined the effect of different combinatorial treatment on cell proliferation and cell cycle distribution. In addition, the effect of combinatorial treatments on proliferative and apoptotic signalling pathway were studied. Our results showed that the synergistic effect presented when A549 cells were treated with docetaxel followed by sorafenib or when A549/D cells were treated in reverse sequence. Furthermore, we suggested that synergistic effect in A549/D cells was caused by inhibiting P-gp function and altering in the balance of growth and apoptotic signalling pathways. Our data suggested a potential role of sorafenib in chemosensitizing docetaxel-resistant cancer cells. This study also provides molecular evidence for applying different therapeutic strategies for patients with different genetic and proteomic profile.

Role of vandetanib in the management of medullary thyroid cancer

Traditionally available treatments, like cytotoxic chemotherapy and external-beam radiation therapy, are limited and essentially ineffective for metastatic medullary thyroid carcinoma (MTC). In the last decade, small-molecule tyrosine kinase inhibitors (TKI) have been introduced in the field of thyroid cancer, after having been shown effective in a wide variety of other tumors. This review focuses on vandetanib (ZD6474, Zactima™; AstraZeneca) and its role in the treatment of MTC. Vandetanib is an oral TKI that targets VEGF receptors 2 and 3, RET, and at higher concentrations, the epidermal growth factor (EGF) receptor. This drug has been tested in two important phase II studies which demonstrated that both the 100 and 300 mg/day dosage of vandetanib have antitumor activity on advanced MTC. A phase III trial (ZETA trial) evaluating vandetanib in 331 patients with locally advanced or metastatic MTC showed a significant prolongation of PFS for patients receiving vandetanib compared with placebo. Toxicity surveillance in all studies reported high rates of adverse effects with diarrhea, rash, fatigue and nausea being the most commonly experienced by patients. Vandetanib is currently approved in the United States for unresectable locally advanced or metastatic MTC and has become a new standard of care in this rare and indolent pathology.

Advances in research of antiangiogenic drugs for gastric cancer

Gastric cancer is the most common cancer of the digestive system and the first leading cause of cancer deaths in China. Conventional surgery and chemotherapeutic regimens can not significantly improve the poor prognosis of gastric cancer. In recent years, molecular targeted therapy has become a hot topic in the treatment of cancers, and many antiangiogenic drugs for treatment of gastric cancer have been developed, including monoclonal antibodies or soluble receptors that bind and neutralize vascular endothelial growth factor (VEGF), tyrosine kinase receptor inhibitors, and antibodies against VEGF receptors (VEGFRs).

Phase I dose-finding study of vandetanib in combination with gemcitabine in locally advanced unresectable or metastatic pancreatic adenocarcinoma

OBJECTIVES

Vandetanib is an oral inhibitor of vascular endothelial growth factor receptor, epidermal growth factor receptor and RET (REarranged during Transfection) signaling. The primary objective of this open-label phase I trial was to determine the maximum tolerated dose (MTD) and recommended dose (RD) of vandetanib in combination with gemcitabine in patients with unresectable, locally advanced or metastatic pancreatic adenocarcinoma (PAC).

METHODS

Patients received vandetanib (100 or 300 mg/day) plus gemcitabine (1,000 mg/m(2) i.v. on days 1, 8 and 15 per 28-day cycle) until disease progression, unacceptable toxicity or withdrawal of patient consent. The MTD was determined by the assessment of dose-limiting toxicity (DLT) during the first 28 days of treatment.

RESULTS

Fifteen patients were treated. No DLTs occurred in the first cohort of vandetanib 100 mg (n = 3) and recruitment continued at the 300-mg dose level. At the 300-mg dose, 3 out of 12 patients (including 2 in the expansion cohort) experienced DLTs (aphasia, elevated liver enzymes and neutropenia; all of them grade 3), thus exceeding the MTD. No objective responses were observed, with stable disease being the best response in 78% of evaluable patients.

CONCLUSIONS

Vandetanib 100 mg/day is the RD in combination with gemcitabine in the treatment of patients with advanced PAC.

Targeted molecular therapy of head and neck squamous cell carcinoma with the tyrosine kinase inhibitor vandetanib in a mouse model

BACKGROUND

We investigated the effects of vandetanib, an inhibitor of vascular endothelial growth factor receptor 2 (VEGFR-2) and epidermal growth factor receptor (EGFR), alone and in combination with paclitaxel in an orthotopic mouse model of human head and neck squamous cell carcinoma (HNSCC).

METHODS

The in vitro effects of vandetanib (ZACTIMA) were assessed in 2 HNSCC cell lines on cell growth, apoptosis, receptor and downstream signaling molecule expression, and phosphorylation levels. We assessed in vivo effects of vandetanib and/or paclitaxel by measuring tumor cell apoptosis, endothelial cell apoptosis, microvessel density, tumor size, and animal survival.

RESULTS

In vitro, vandetanib inhibited the phosphorylation of EGFR and its downstream targets in HNSCC cells and inhibited proliferation and induced apoptosis of HNSCC cells and extended survival and inhibited tumor growth in nude mice orthotopically injected with human HNSCC.

CONCLUSION

Vandetanib has the potential to be a novel molecular targeted therapy for HNSCC.

A novel antiangiogenic approach for adjuvant therapy of pancreatic carcinoma

INTRODUCTION

Surgical therapy remains the only curative option for pancreatic ductal adenocarcinoma. But even after complete resection, almost all patients suffer from local tumor recurrence. Current standard adjuvant therapy with gemcitabine does not impressively affect the recurrence rate. The aim of this study was to evaluate a novel anti-angiogenic adjuvant treatment strategy by targeting the vascular endothelial growth factor receptor (VEGFR). We assayed the effects of a novel VEGFR inhibitor (ZK261991) on pancreatic carcinoma. ZK261991 is a highly selective and potent VEGFR-kinase inhibitor, which is orally available.

METHODS

We used a previously established nude mouse orthotopic pancreatic cancer resection model. Subcutaneous donor tumor fragments (1 mm(3)) derived from human pancreatic cancer cell lines HPAF-2 and AsPC-1 were implanted in the pancreatic tail of 48 nude mice. Fourteen days afterwards, all mice underwent a histologically confirmed curative tumor resection followed by daily adjuvant oral therapy with ZK261991 (50 mg/kg; n = 24) vs. placebo (n = 24). The mice were sacrificed after 12 weeks of therapy or in case of defined endpoints. All sacrificed mice underwent autopsy. A dissemination score (local and systemic tumor spread), size of recurrent tumor mass, survival, and weight loss/gain were surveyed.

RESULTS

Kaplan-Meier analysis of survival showed a significant benefit for mice treated with ZK261991 after HPAF-2 tumor resection: 83.8 days (95% CI 73.9-93.6) vs. 60.9 days (95% CI 48.9-73.0), p = 0.006. Adjuvant treatment with ZK261991 of AsPC-1-derived tumors showed a tendency towards a benefit compared to control but no significant difference: 75.8 days (95% CI 59.7-91.9) vs. 65.7 days (95% CI 51.6-79.7). There were no significant differences in dissemination score and size of recurrent tumor mass between the treatment groups.

CONCLUSION

Adjuvant anti-angiogenic therapy with the novel VEGFR-inhibitor ZK261991 resulted in a significant survival benefit after curative tumor resection in a clinically relevant orthotopic animal model of pancreatic cancer. Combination of anti-angiogenic treatment with cytotoxic agents may further improve the results of adjuvant therapy.

Assessment of acute antivascular effects of vandetanib with high-resolution dynamic contrast-enhanced computed tomographic imaging in a human colon tumor xenograft model in the nude rat

Tumor size is not a reliable marker for the assessment of early antivascular effects of antiangiogenics. In the present study, we used 200-microm in-plane high-resolution dynamic contrast-enhanced computed tomography (DCE-CT) to noninvasively assess the immediate antivascular effects of vandetanib in a subcutaneous human colon cancer (LoVo) xenograft model in nude rats and to investigate correlation between changes in CT perfusion parameters and tumor volume or immunohistochemical end points. At 3 to 4 weeks after LoVo cell implantation, the animal was gavaged with either vandetanib (50 mg/kg) or vehicle twice (22 hours apart) and scanned with a preclinical DCE-CT scanner before (0 hour) and after treatment (24 hours). Quantitative maps of blood flow (BF) and volume (BV) of the tumor were calculated from the acquired DCE-CT images. The rats were divided into nonhypovascular, hypovascular, and combined (regardless of vascularity) groups. In the nonhypovascular group, significant decreases in both tumor BF and BV were observed in the vandetanib-treated rats compared with increases in the vehicle-treated rats. A significant decrease in BV was detected in the vandetanib-treated rats in the combined group as well. No differences in tumor growth, vascular endothelial growth factor expression, microvessel density, or apoptosis were observed between vandetanib- and vehicle-treated rats in all three groups. These results demonstrate that BF and BV imaging biomarkers from DCE-CT imaging can be used for rapid monitoring of immediate (24 hours after) antimicrovascular effects of vandetanib on tumors, even in the absence of significant changes of tumor volume or clinically relevant immunohistochemical end points.

The molecular targets for the diagnosis and treatment of pancreatic cancer

Pancreatic cancer is considered an aggressive malignancy that responds poorly to current treatments and therefore has a dismal survival rate. This disease is usually not diagnosed until a late stage, at which point palliative chemotherapy with the purine analogue gemcitabine and/or a fluoropyrimidine or a platinum agent is the standard approach. There are some new data on the molecular and genetic changes that take place in pancreatic cancer, which may facilitate the accuracy of diagnosis and efficacy of treatments. However, translational efforts in clinical practice have increased clinicians' options with a targeted agent, erlotinib, in combination with the standard gemcitabine chemotherapy. Many other novel drugs currently being tested in the field of pharmaco-oncology target various altered biological pathways and molecules. Nevertheless, the lack of clinically significant improvements in treatments is rendering efforts to develop methods of early diagnosis both more urgent and promising. The aim of this review was to summarize the molecular basis of pancreatic carcinogenesis and the latest developments in diagnosis by molecular means, focusing on the results of clinical research into targeted and personalized treatments.

Dual inhibition of vascular endothelial growth factor receptor and epidermal growth factor receptor is an effective chemopreventive strategy in the mouse 4-NQO model of oral carcinogenesis

Despite recent therapeutic advances, several factors, including field cancerization, have limited improvements in long-term survival for oral squamous cell carcinoma (OSCC). Therefore, comprehensive treatment plans must include improved chemopreventive strategies. Using the 4-nitroquinoline 1-oxide (4-NQO) mouse model, we tested the hypothesis that ZD6474 (Vandetanib, ZACTIMA) is an effective chemopreventive agent. CBA mice were fed 4-NQO (100 μg/mL) in their drinking water for 8 weeks and then randomized to no treatment or oral ZD6474 (25 mg/kg/d) for 24 weeks. The percentage of animals with OSCC was significantly different between the two groups (71% in control and 12% in the ZD6474 group; P ≤ 0.001). The percentage of mice with dysplasia or OSCC was significantly different (96% in the control and 28% in the ZD6474 group; P ≤ 0.001). Proliferation and microvessel density scores were significantly decreased in the ZD6474 group (P ≤ 0.001 for both). Although proliferation and microvessel density increased with histologic progression in control and treatment cohorts, epidermal growth factor receptor and vascular endothelial growth factor receptor-2 phosphorylation was decreased in the treatment group for each histologic diagnosis, including mice harboring tumors. OSCC from ZD6474-treated mice exhibited features of epithelial to mesenchymal transition, as shown by loss E-cadherin and gain of vimentin protein expression. These data suggest that ZD6474 holds promise as an OSCC chemopreventive agent. They further suggest that acquired resistance to ZD6474 may be mediated by the expression of an epithelial to mesenchymal transition phenotype. Finally, the data suggests that this model is a useful preclinical platform to investigate the mechanisms of acquired resistance in the chemopreventive setting.

The marine compound spongistatin 1 targets pancreatic tumor progression and metastasis

Treatment of pancreatic cancer remains a major challenge and new anticancer drugs are urgently required. Our study presents the marine natural compound spongistatin 1 as a promising experimental drug. Spongistatin 1 was applied in an orthotopic in vivo model of human pancreatic cancer. Spongistatin 1 significantly reduced tumor growth, which correlates with a strong apoptosis induction (DNA-fragmentation) and long-term effects on clonogenic survival of pancreatic tumor cells (L3.6pl) in vitro. In addition, the formation of metastasis was reduced in spongistatin 1-treated mice, which is in line with a diminished MMP-9 activity in tumor tissue determined by zymography. Based on the pronounced efficacy of spongistatin 1, the underlying mechanisms were studied in more detail. In vitro adhesion, as well as migration, and invasion assays showed spongistatin 1 to influence these critical steps in the metastatic cascade. Furthermore, spongistatin 1 induced anoikis in L3.6pl cells. Exposure to spongistatin 1 leads to phosphorylation, and thus inactivation of the antiapoptotic protein Bcl-2 in pancreatic tumor cells. siRNA experiments silencing Bcl-2 suggest a role of Bcl-2 in anoikis and cell migration. Taken together, spongistatin 1 not only proved to be a potent experimental drug but also served as a chemical tool to examine the role of the antiapoptotic protein Bcl-2 in pancreas carcinoma, thereby supporting the hypothesis of a link between apoptosis signaling and metastasis.

E1B-55kD-deleted oncolytic adenovirus armed with canstatin gene yields an enhanced anti-tumor efficacy on pancreatic cancer

Conditionally-replicating adenovirus (CRAd) therapy is currently being tested against pancreatic cancer and has shown some promise. To improve the efficacy, a novel virus CRAd-Cans was designed by deletion of E1B-55kDa gene for selective replication in tumor cells, as well as carrying a new angiogenesis inhibitor gene, canstatin. CRAd-Cans mediated higher expression of canstatin in BxPC-3 pancreatic cancer cell line compared to the replication-deficient adenovirus Ad5-Cans. The modified CRAd-Cans manifested the same selective replication and cytocidal effects in pancreatic cancer cells as ONYX-015 in vitro, yet showed greater reduction of tumor growth in nude mice with markedly prolonged survival rate in vivo (P<0.05), compared to that of either ONYX-015 or Ad5-Cans. Pathological examination revealed viral replication, decreased microvessel density and increased cancer cell apoptosis in CRAd-Cans-treated xenografts. The results suggest that the novel oncolytic virus CRAd-Cans, showing synergistic effects of oncolytic therapy and anti-angiogenesis therapy, is a new promising therapeutics for pancreatic cancer.

ZD6474 inhibits Src kinase leading to apoptosis of imatinib-resistant K562 cells

ZD6474 is an orally available, small-molecule tyrosine kinase inhibitor. This study explores the effect of ZD6474 on imatinib-resistant K562 cell lines, which show markedly increased SRC family kinases (SFKs) activity. ZD6474 induces growth arrest and apoptosis of imatinib-resistant and parental K562 cells, as well as inhibition of Src activity and its downstream effectors, the anti-apoptotic Bcl-2 family. ZD6474 treatment also inhibits the activity of STAT3 and reactivation of its activity results in suppression of the anti-tumor effects of SFKs inhibitors. A single oral administration of ZD6474 produced dose-dependent inhibition of imatinib-resistant K562 cells xenograft tumors. These results suggest that clinical assessment of ZD6474 against imatinib-resistant CML is warranted.

Intravital microscopy of tumor angiogenesis and regression in the dorsal skin fold chamber: mechanistic insights and preclinical testing of therapeutic strategies

Tumor angiogenesis is a major step in tumor progression to clinically symptomatic cancer and thus a potential target for cancer therapy. It is essential to understand the fundamental mechanisms of the angiogenic processes to provide a rational for testing inhibitory strategies for cancer treatment. The dorsal skin fold chamber provides a suitable (chronic) model for intravital microscopy to monitor the same tumor in time-lapse imaging series and in real-time functional analysis e.g., of blood flow. Adaptation of this model to several rodent species and tumor types has led to numerous physical and drug based therapy options. With modification of implantation techniques, motility and invasion of individual cells can be visualized, in addition to angiogenesis and microcirculation. Modern fluorescent techniques such as ex vivo labelling of specific cell populations and the introduction of stably fluorescent protein expressing cell lines further enhance the suitability of this technique. In addition, laser scanning and multiphoton microscopy in combination with genetically altered mouse strains and cell lines are making the DCSF even more attractive for mechanistic and interventional studies in cancer research. Here we review the preparation as well as the applications of the DCSF in tumor angiogenesis.

Small molecule tyrosine kinase inhibitors in pancreatic cancer

Pancreatic cancer has proven to be chemo-resistant, with gemcitabine being the only cytotoxic agent approved for advanced pancreatic cancer since 1996. Tyrosine kinase inhibitors represent a newer generation of chemotherapeutic agents targeting specific tumor pathways associated with carcinogenesis including cell cycle control, signal transduction, apoptosis and angiogenesis. These agents present a more selective way of treating pancreatic cancer. Erlotinib is the prototype of the tyrosine kinase inhibitors with proven efficacy in advanced pancreatic cancer and has been recently approved in that setting. Multiple other tyrosine kinase inhibitors targeting the VEGFR, PDGFR, and Src kinases are in various phases of clinical trials testing. The preliminary results of these trials have been disappointing. Current challenges in pancreatic cancer clinical trials testing include improving patient selection, identifying effective combinations, improving the predictive value of current preclinical models and better study designs. This review summarizes the present clinical development of tyrosine kinase inhibitors in pancreatic cancer and strategies for future drug development.

New treatment options for advanced pancreatic cancer

Pancreatic cancer has a very high mortality rate and affects approximately 230,000 individuals worldwide. Gemcitabine has become established as the standard therapy for advanced pancreatic cancer; however, the survival advantage is small. Adjuvant chemotherapy using either 5-fluorouracil or gemcitabine is now established in pancreatic cancer as an alternative therapy. Combinations of gemcitabine with either platin agents or capecitabine may be advantageous. Anti-EGFR and anti-VEGF agents have been unsuccessful but multiple tyrosine kinase inhibitors are under investigation. Of the increasing number of immunological agents, the GV1001 antitelomerase vaccine holds some interest. Targeted agents against important mitogenic pathways, including MEK/ERK, Src, PI3K/Akt, mTOR, Hedgehog and NF-kappaB, as well as agents targeting histone deacetylase, poly(ADP-ribose) polymerase, heat shock protein 90 and other agents such as beta-lapachone, hold considerable interest for further development. However, the probability of individual success is low.

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.

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.

Stem cell-based therapy in gastroenterology and hepatology

Protagonists of a new scientific era, stem cells are promising tools on which regenerative medicine relies for the treatment of human pathologies. Stem cells can be obtained from various sources, including embryos, fetal tissues, umbilical cord blood, and also terminally differentiated organs. Once forced to expand and differentiate into functional progenies, stem cells may become suitable for cell replacement and tissue engineering. The manipulation and/or stimulation of adult stem cells seems to be particularly promising, as it could improve the endogenous regenerative potential without risks of rejection and overcome the ethical and political issues related to embryonic stem cell research. Stem cells are already leaving the bench and reaching the bedside, despite an incomplete knowledge of the genetic control program driving their fate and plasticity. In gastroenterology and hepatology, the first attempts to translate stem cell basic research into novel therapeutic strategies have been made for the treatment of several disorders, such as inflammatory bowel diseases, diabetes mellitus, celiachy and acute or chronic hepatopaties. Nonetheless, critical aspects need to be further addressed, including the long-term safety, tolerability and efficacy of cell-based treatments, as well as their carcinogenic potential. Aim of this review is to summarize the state-of-the-arts on gastrointestinal and hepatic stem cells and on stem cell-based therapies in gastroenterology and hepatology, highlighting both the benefits and the potential risks of these new tools for the treatment and prevention of human diseases.