The Emerging Role of Vascular Endothelial Growth Factor Receptor Tyrosine Kinase Inhibitors

Simultaneous EGFR and VEGF Alterations in Non-Small Cell Lung Carcinoma Based on Tissue Microarrays

Background

Epidermal growth factor receptor (EGFR) overexpression is observed in significant proportions of non-small cell lung carcinomas (NSCLC). Furthermore, overactivation of vascular endothelial growth factor (VEGF) leads to increased angiogenesis implicated as an important factor in vascularization of those tumors.

Patients and Methods

Using tissue microarray technology, forty-paraffin ( n = 40) embedded, histologically confirmed primary NSCLCs were cored and re-embedded into a recipient block. Immunohistochemistry was performed for the determination of EGFR and VEGF protein levels which were evaluated by the performance of computerized image analysis. EGFR gene amplification was studied by chromogenic in situ hybridization based on the use of EGFR gene and chromosome 7 centromeric probes.

Results

EGFR overexpression was observed in 23/40 (57.5%) cases and was correlated to the stage of the tumors ( p = 0.001), whereas VEGF was overexpressed in 35/40 (87.5%) cases and was correlated to the stage of the tumors ( p = 0.005) and to the smoking history of the patients ( p = 0.016). Statistical significance was assessed comparing the protein levels of EGFR and VEGF ( p = 0.043, k = 0.846). EGFR gene amplification was identified in 2/40 (5%) cases demonstrating no association to its overall protein levels ( p = 0.241), whereas chromosome 7 aneuploidy was detected in 7/40 (17.5%) cases correlating to smoking history of the patients ( p = 0.013).

Conclusions

A significant subset of NSCLC is characterized by EGFR and VEGF simultaneous overexpression and maybe this is the eligible target group for the application of combined anti-EGFR/VEGF targeted therapies at the basis of genetic deregulation (especially gene amplification for EGFR).

Molecular testing in lung cancer in the era of precision medicine

The clinical expectations how pathologists should submit lung cancer diagnosis have changed dramatically. Until mid 90-ties a clear separation between small cell lung carcinoma (SCLC) and non-small cell lung carcinoma (NSCLC) was mostly sufficient. With the invention of antiangiogenic treatment a differentiation between squamous and non-squamous NSCLC was requested. When epidermal growth factor receptor (EGFR) mutation was detected in patients with pulmonary adenocarcinomas and subsequent specific treatment with tyrosine kinase inhibitors (TKIs) was invented, sub-classification of NSCLC and molecular analysis of the tumor tissue for mutations was asked for. Pathologists no longer submit just a diagnosis, but instead are involved in a multidisciplinary team for lung cancer patient management. After EGFR several other driver genes such as echinoderm microtubule associated protein like 4-AL-Kinase 1 (EML4-ALK1), c-ros oncogene 1, receptor tyrosine kinase (ROS1), discoidin domain receptor tyrosine kinase 2 (DDR2), fibroblast growth factor receptor 1 (FGFR1) were discovered, and more to come. Due to new developments in bronchology (EUS, EBUS) the amount of tissue submitted for diagnosis and molecular analysis is decreasing, however, the genes to be analyzed are increasing. Many of these driver gene aberrations are inversions or translocations and thus require FISH analysis. Each of these analyses requires a certain amount of tumor cells or one to two tissue sections from an already limited amount of tissues or cells. In this respect new genetic test systems have been introduced such as next generation sequencing, which enables not only to detect multiple mutations in different genes, but also amplifications and fusion genes. As soon as these methods have been validated for routine molecular analysis this will enable the analysis of multiple genetic changes simultaneously. In this review we will focus on genetic aberrations in NSCLC, resistance to new target therapies, and also to methodological requirements for a meaningful evaluation of lung cancer tissue and cells.

Monoclonal antibodies in chronic lymphocytic leukemia

Multiple options are now available for the treatment of chronic lymphocytic leukemia. Over the last 10 years, monoclonal antibodies have become an integral part of the management of this disease. Alemtuzumab has received approval for use in patients with fludarabine-refractory chronic lymphocytic leukemia. Rituximab has been investigated extensively in chronic lymphocytic leukemia both as a single agent and in combination with chemotherapy and other monoclonal antibodies. Epratuzumab and lumiliximab are newer monoclonal antibodies in the early phase of clinical development. This article will review the monoclonal antibodies more commonly used to treat chronic lymphocytic leukemia, the results obtained with monoclonal antibodies as single agents and in combination with chemotherapy, and other biological agents and newer compounds undergoing clinical trials.

Treatment outcome for patients with primary NSCLC and synchronous solitary metastasis

INTRODUCTION

Non-small cell lung cancer (NSCLC) patients with synchronous solitary metastasis were generally considered as stage IV and believed to be incurable. Recently, growing evidence has indicated that surgical treatment may provide these patients with a survival benefit. The aim of this study was to retrospectively analyze the effectiveness of different treatments for primary tumors and solitary metastases.

MATERIALS AND METHODS

Patients older than 18 years with histologically confirmed stage IV NSCLC and a confirmed synchronous solitary metastasis that diagnosed within 2 months of primary NSCLC. Patients with uncontrolled massive pleural effusion were excluded. Between February 2002 and October 2010, 213 patients were considered eligible and enrolled in this cohort.

RESULTS

The median survival time (MST) for the 213 patients was 12.6 months. Forty-five patients received primary pulmonary tumor surgery in the entire cohort. The MSTs of patients who received primary tumor resection and those who did not were 31.8 and 11.4 months (p < 0.01). The MST of the patients with solitary brain metastasis was 12.3 months. Forty-one patients who received brain surgical treatment or SRS had a MST of 15.4 months and others who only received WBRT had a MST of 11.5 months (p = 0.002). Gender, the stage of the primary tumor, PS and whether the primary tumor was removed all affected prognosis independently.

CONCLUSIONS

Aggressive local and metastasis treatments could lead to better clinical outcomes and thus provide an option for clinicians in the future management of patients with NSCLC and synchronous solitary metastasis.

Cediranib: a VEGF receptor tyrosine kinase inhibitor

Cediranib is a potent inhibitor of the VEGF family receptor tyrosine kinases, and a new agent in cancer treatment. The drug has shown promising activity in a variety of solid malignancies, in preclinical models and in clinical trials. Its pharmacokinetics allow for a convenient once-daily administration, with a toxicity profile that is very similar to other VEGF inhibitors. Its main side effects include hypertension, nausea, dysphonia, fatigue and diarrhea. Adverse events seem to be manageable, especially when used in doses lower than 45 mg/day. Studies have shown some activity as a single agent or in combination in advanced tumors, but not enough to secure its approval for routine use up to now. Clinical trials are still evaluating the role of cediranib in combination chemotherapy with cytotoxic agents.

Randomized, double-blind trial of carboplatin and paclitaxel with either daily oral cediranib or placebo in advanced non-small-cell lung cancer: NCIC clinical trials group BR24 study

PURPOSE This phase II/III double-blind study assessed efficacy and safety of cediranib with standard chemotherapy as initial therapy for advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS Paclitaxel (200 mg/m(2)) and carboplatin (area under the serum concentration-time curve 6) were given every 3 weeks, with daily oral cediranib or placebo at 30 mg (first 45 patients received 45 mg). Progression-free survival (PFS) was the primary outcome of the phase II interim analysis; phase III would proceed if the hazard ratio (HR) for PFS < or = 0.77 and toxicity were acceptable. Results A total of 296 patients were enrolled, 251 to the 30-mg cohort. The phase II interim analysis demonstrated a significantly higher response rate (RR) for cediranib than for placebo, HR of 0.77 for PFS, no excess hemoptysis, and a similar number of deaths in each arm. The study was halted to review imbalances in assigned causes of death. In the primary phase II analysis (30-mg cohort), the adjusted HR for PFS was 0.77 (95% CI, 0.56 to 1.08) with a higher RR for cediranib than for placebo (38% v 16%; P < .0001). Cediranib patients had more hypertension, hypothyroidism, hand-foot syndrome, and GI toxicity. Hypoalbuminemia, age > or = 65 years, and female sex predicted increased toxicity. Survival update (N = 296) 10 months after study unblinding favored cediranib over placebo (median of 10.5 months v 10.1 months; HR, 0.78; 95% CI, 0.57 to 1.06; P = .11). Causes of death in the cediranib 30-mg cohort were NSCLC (81%), protocol toxicity +/- NSCLC (13%), and other (6%); for the placebo group, they were 98%, 0%, and 2%, respectively. CONCLUSION The addition of cediranib to carboplatin/paclitaxel results in improved response and PFS, but does not appear tolerable at a 30-mg dose. Consequently, the National Cancer Institute of Canada Clinical Trials Group and the Australasian Lung Cancer Trials Group initiated a randomized, double-blind, placebo-controlled trial of cediranib 20 mg with carboplatin and paclitaxel in advanced NSCLC.

VEGF and ki 67 expression in squamous cell carcinoma of the tongue: An immunohistochemical and computerized image analysis study

Over-expression of ki 67 and vascular endothelial growth factor (VEGF) is a frequent finding in squamous cell carcinoma (SCC) of the oral mucosa. The expression of VEGF and ki 67 proteins was studied in a cohort of 87 patients with primary, previously untreated SCC of the tongue, using computerized image analysis (CIA) in order to determine the potential prognostic significance of these factors. Immunohistochemical analysis was performed with monoclonal anti-ki 67 (MIB 1) and anti-VEGF antibodies. A digital image analysis assay was applied for the evaluation of the results. Using CIA, VEGF over-expression was observed in 24/87 (27.5%) of the examined cases and this finding correlated to the stage of the disease (p=0.05). ki 67 was over-expressed in 49/87 (56.3%) of the cases and correlated to the size of the tumors (p=0.05). Cox regression analysis showed that there was no prognostic significance associating VEGF protein expression to survival status of the examined patients (p=0.77), whereas ki 67 over-expression was strongly correlated to poor prognosis (p=0.017). The size of the primary tumors was also strongly correlated to survival status of the patients (p=0.024), whereas stage of disease showed a borderline statistical significance (p=0.091).

Novel tool to suppress cell proliferation in vivo demonstrates that myocardial and coronary vascular growth represent distinct developmental programs

Cell proliferation, differentiation, and vascular growth are coordinated processes that are essential for embryonic development, tissue repair, and disease pathogenesis. Of interest, whether these critical processes are dependent upon each other has not been thoroughly explored. We have generated mice that conditionally express the cell cycle inhibitor p27(Kip1), following Cre-mediated recombination, as a tool to separate tissue proliferation from other cellular processes. Using the embryonic heart as a model, we show that myocardial proliferation and coronary development are genetically separable processes. Forced expression of p27, in both a wild-type and in a genetically sensitized background, resulted in ventricular hypoplasia without having any substantial effects on coronary development. We further demonstrate that Hedgehog signaling, which is essential for coronary vascular growth, does not control myocardial proliferation. Together, these studies strongly suggest that myocardial cell proliferation and coronary development are genetically separable programs exemplifying one of the many potential uses of this genetic tool.

Improved low molecular weight Myc-Max inhibitors

Compounds that selectively prevent or disrupt the association between the c-Myc oncoprotein and its obligate heterodimeric partner Max (Myc-Max compounds) have been identified previously by high-throughput screening of chemical libraries. Although these agents specifically inhibit the growth of c-Myc-expressing cells, their clinical applicability is limited by their low potency. We describe here several chemical modifications of one of these original compounds, 10058-F4, which result in significant improvements in efficacy. Compared with the parent structure, these analogues show enhanced growth inhibition of c-Myc-expressing cells in a manner that generally correlates with their ability to disrupt c-Myc-Max association and DNA binding. Furthermore, we show by use of a sensitive fluorescence polarization assay that both 10058-F4 and its active analogues bind specifically to monomeric c-Myc. These studies show that improved Myc-Max compounds can be generated by a directed approach involving deliberate modification of an index compound. They further show that the compounds specifically target c-Myc, which exists in a dynamic and relatively unstructured state with only partial and transient alpha-helical content.

Molecular Biology for the Radiation Oncologist: the 5Rs of Radiobiology meet the Hallmarks of Cancer

Recent advances in our understanding of the biology of cancer have provided enormous opportunities for the development of novel therapies against specific molecular targets. It is likely that most of these targeted therapies will have only modest single agent activities but may have the potential to accentuate the therapeutic effects of ionising radiation. In this introductory review, the 5Rs of classical radiobiology are interpreted in terms of their relationship to the hallmarks of cancer. Future articles will focus on the specific hallmarks of cancer and will highlight the opportunities that exist for designing new combination treatment regimens.

Gastrin-releasing peptide receptor as a molecular target in experimental anticancer therapy

Over the last two decades, several lines of experimental evidence have suggested that the gastrin-releasing peptide (GRP) may act as a growth factor in many types of cancer. For that reason, gastrin-releasing peptide receptor (GRPR) antagonists have been developed as anticancer candidate compounds, exhibiting impressive antitumoral activity both in vitro and in vivo in various murine and human tumors. In this article, the GRPR cell surface expression profile in human malignancies is reviewed aiming at the identification of potential tumor types for future clinical trials with GRP analogues and antagonists. In this review, we summarize the current literature regarding the GRPR status in human malignancies. Source data were obtained by searching all published material available through Medline, PubMed and relevant articles from 1971 to 2006. The data available demonstrated a high expression of GRPRs in a large spectrum of human cancers, demonstrating the potential relevance of this intracellular signaling pathway in various human tumor models. The GRPR may be an interesting target for therapeutic intervention in human malignancies, as carriers for cytotoxins, immunotoxins or radioactive compounds, being also a potential tool for tumor detection.

Diagnostic relevance of overexpressed mRNA of novel oncogene with kinase-domain (NOK) in lung cancers

There have been no target molecules that have enabled us to diagnose lung cancer with high sensitivity and specificity even in its early clinical stages. A molecule termed novel oncogene with kinase-domain (NOK) was recently reported as a receptor protein tyrosine kinase that is expressed in some cancer cell lines and causes the transformation and progressive proliferation of normal cells. Therefore, NOK could be a possible candidate for a diagnostic marker for human cancers. We examined here, the degree of NOK mRNA expression in lung cancer tissues and compared it to that in non-cancerous tissues. More than 60% of non-cancerous samples (8/13) showed undetectable levels of mRNA. In contrast, NOK mRNA was detected in 97.6% (40/41) of lung cancer tissues, resulting in a sensitivity of 80.5% and a specificity of 92.3% that was estimated using the cutoff obtained from receiver operating characteristic curve analysis. Further, NOK mRNA expression was found to be elevated in 92.3% (12/13) of cancerous tissues when paired cancerous and non-cancerous tissues from identical patients were compared. There were no obvious correlations between clinicopathological factors and NOK mRNA expression; however, NOK mRNA was highly expressed even at the early clinical stages of the cancer. These results suggest that NOK mRNA might be a new tool to support the diagnosis of lung cancers, irrespective of the clinical stages.

VEGF/VEGFR signalling as a target for inhibiting angiogenesis

VEGFs and a respective family of tyrosine kinases receptors (VEGFRs) are key proteins modulating angiogenesis, the formation of new vasculature from an existing vascular network. There has been considerable evidence in vivo, including clinical observations, that abnormal angiogenesis is implicated in a number of disease conditions, which include rheumatoid arthritis, inflammation, cancer, psoriasis, degenerative eye conditions and others. Antiangiogenic therapies based on inhibition of VEGF/VEGFR signalling were reported to be powerful clinical strategies in oncology and ophthalmology. Current efforts have yielded promising clinical data for several antiangiogenic therapeutics. In this review, the authors elucidate key aspects of VEGFR signalling, as well as clinically relevant strategies for the inhibition of VEGF-induced angiogenesis, with an emphasis on small-molecule VEGFR inhibitors.

Targeted therapy in advanced non-small cell lung cancer (NSCLC): where do we stand?

Cytotoxic chemotherapy has helped improve the outcomes in patients with advanced non-small cell lung cancer (NSCLC), but we seem to have reached a plateau with respect to the benefit obtained. Also, a large subset of elderly patients and those with a poor performance status cannot tolerate these drugs at recommended doses. There is a growing need to incorporate newer drugs with different mechanisms of action and better safety profile. The epidermal growth factor receptor family (EGFR) and vascular endothelial growth factor (VEGF) have been identified as potential targets and agents acting specifically against these targets have been developed with the hope of improving outcomes. Although recent data with the small molecule EGFR tyrosine kinase inhibitors have been disappointing, there have been instances of dramatic responses thereby raising questions about the ideal patient to whom these drugs should be administered. Cetuximab, the anti-EGFR antibody has shown promising results. Bevacizumab, the anti-VEGF antibody was the first drug to demonstrate a survival benefit in first line treatment when added to chemotherapy. This review will briefly discuss the important trials using these targeted agents in advanced NSCLC.