Report of the National Oncology Research and Developement Consortium, 2003

Consorcial projects focused on 5 cancer types, breast-, colorectal-, head and neck- and pediatric cancers, and malignant melanoma. Breast cancer studies revealed unique splicing mechanisms concerning BRCA1. In sporadic breast cancers the involvement of DNA-repair genes was proved to be dependent on the histological type. Bone-metastatic tumors have been characterized by decreased NM23 and increased c-met and p53 expressions. C-erbB2 genotype of the primary tumor was not maintained frequently in bone metastases. Application of DNA-microarray and quantitative PCR technologies improved the prediction of therapeutic sensitivity of breast cancers. Colorectal cancer studies revealed regional inhomogenities (clusters) in various geographical regions of Hungary, which were distinct in the case of colonic and rectal cancers. To increase the sensitivity of fecal blood test of colorectal cancer screening, a new double-antibody test was developed and tested in a large cohort of patients. Genetic analysis revealed that hypermethylation is a significant factor in microsatellite instability which, and plays a role in silencing of APC and E-cadherin genes as well. The Hungarian pattern of TS polymorphism was also determined and was correlated not only with the efficacy of 5-FU treatment but with the progression of the disease as well. Population-based studies have been carried out in head and neck cancer patients (HNC) and smokers as well to reveal the genetic background of increasing tumor incidence. These studies revealed polymorphism in XRCC1/3 methylation enzyme gene which has preventive role. Other studies found frequent local immunosuppression in HNC patients. Studies indicated that the success of irradiation in this cancer type is dependent on the anti-vascular effects. Pediatric cancer studies determined the parameters of neuroblastoma screening based on VMA measurements. New splice variants of the WT1 gene involved in the monitoring of MRD of ALL patients was also described this year. We also obtained positive experimental data for the retinoic acid therapy of ALL. Melanoma studies extensively used DNA-microarray technology which identified 4 melanoma-specific and 2 melanoma progression-specific genes. In experimental human melanoma xenograft models we have identified 3 anti-metastatic agents: low molecular weight heparin, 2-methoxyestradiol and erythropoietin-alpha, where the later was characterized by specific effects on tumor vasculature.     

Targeting EGFR resistance networks in head and neck cancer

A core set of oncoproteins is overexpressed or functionally activated in many types of cancer, and members of this group have attracted significant interest as subjects for development of targeted therapeutics. For some oncoproteins such as EGFR/ErbB1, both small molecule and antibody agents have been developed and applied in the clinic for over a decade. Analysis of clinical outcomes has revealed an initially unexpected complexity in the response of patients to these agents. Diverse factors, including developmental lineage of the tumor progenitor cell, co-mutation or epigenetic modulation of genes encoding proteins in an extended EGFR signaling network or regulating core survival responses in individual tumors, and environmental factors including inflammatory agents and viral infection, all have been identified as modulating response to treatment with EGFR-targeted drugs. Second and third generation therapeutic strategies increasingly incorporate knowledge of cancer type-specific signaling environments, in a more personalized treatment approach. This review takes squamous cell carcinoma of the head and neck (SCCHN) as a specific example of an EGFR-involved cancer with idiosyncratic biological features that influence design of treatment modalities, with particular emphasis on commonalities and differences with other cancer types.     

Growth Inhibition of Head and Neck Squamous Cell Carcinoma Cells by sgRNA Targeting the Cyclin D1 mRNA Based on TRUE Gene Silencing

Head and neck squamous cell carcinoma (HNSCC) exhibits increased expression of cyclin D1 (CCND1). Previous studies have shown a correlation between poor prognosis of HNSCC and cyclin D1 overexpression. tRNase ZL-utilizing efficacious gene silencing (TRUE gene silencing) is one of the RNA-mediated gene expression control technologies that have therapeutic potential. This technology is based on a unique enzymatic property of mammalian tRNase ZL, which is that it can cleave any target RNA at any desired site by recognizing a pre-tRNA-like complex formed between the target RNA and an artificial small guide RNA (sgRNA). In this study, we designed several sgRNAs targeting human cyclin D1 mRNA to examine growth inhibition of HNSCC cells. Transfection of certain sgRNAs decreased levels of cyclin D1 mRNA and protein in HSC-2 and HSC-3 cells, and also inhibited their proliferation. The combination of these sgRNAs and cisplatin showed more than additive inhibition of cancer cell growth. These findings demonstrate that TRUE gene silencing of cyclin D1 leads to inhibition of the growth of HNSCC cells and suggest that these sgRNAs alone or combined with cisplatin may be a useful new therapy for HNSCCs.     

Can EGFR be a therapeutic target in breast cancer?

Epidermal growth factor receptor (EGFR) is highly expressed in certain cancer types and is involved in regulating the biological characteristics of cancer progression, including proliferation, metastasis, and drug resistance. Various medicines targeting EGFR have been developed and approved for several cancer types, such as lung and colon cancer. To date, however, EGFR inhibitors have not achieved satisfactory clinical results in breast cancer, which continues to be the most serious malignant tumor type in females. Therefore, clarifying the underlying mechanisms related to the ineffectiveness of EGFR inhibitors in breast cancer and developing new EGFR-targeted strategies (e.g., combination therapy) remain critical challenges. Various studies have demonstrated aberrant expression and maintenance of EGFR levels in breast cancer. In this review, we summarize the regulatory mechanisms underlying EGFR protein expression in breast cancer cells, including EGFR mutations, amplification, endocytic dysfunction, recycling acceleration, and degradation disorders. We also discuss potential therapeutic strategies that act directly or indirectly on EGFR, including reducing EGFR protein expression, treating the target protein to mediate precise clearance, and inhibiting non-EGFR signaling pathways. This review should provide new therapeutic perspectives for breast cancer patients with high EGFR expression.     

The cytoplasmic expression of FSTL3 correlates with colorectal cancer progression,metastasis status and prognosis

Follistatin-like (FSTL) family members are associated with cancer progression. However, differences between FSTL members with identical cancer types have not been systematically investigated. Among the most malignant tumours worldwide, colorectal cancer (CRC) has high metastatic potential and chemoresistance, which makes it challenging to treat. A systematic examination of the relationship between the expression of FSTL family members in CRC will provide valuable information for prognosis and therapeutic development. Based on large cohort survival analyses, we determined that FSTL3 was associated with a significantly worse prognosis in CRC at the RNA and protein levels. Immunohistochemistry staining of CRC specimens revealed that FSTL3 expression levels in the cytosol were significantly associated with a poor prognosis in terms of overall and disease-free survival. Molecular simulation analysis showed that FSTL3 participated in multiple cell motility signalling pathways via the TGF-β1/TWIST1 axis to control CRC metastasis. The findings provide evidence of the significance of FSTL3 in the oncogenesis and metastasis of CRC. FSTL3 may be useful as a diagnostic or prognostic biomarker, and as a potential therapeutic target.     

Developments in cancer management by innovative genomics. 2006 report of the National Cancer Consortium

Research on developing molecular diagnostics for hereditary cancers resulted in establishing diagnostic services for familiar polyposis and non-polyposis patients (mutation determination of APC, MYH, STK11, SMAD4, MLH1, MSH2). In familiar testicular cancers the role of gr/gr gene on Y chromosome was identified. Molecular diagnostic tool was established to monitor the progression of follicular lymphoma using Bcl-2/IgH fusion sequences. Molecular diagnostic tools were developed to monitor circulating endothelial precursor cells (CEP) as well and the technique was tested in lung cancer patients. In malignant melanoma we have tested several potential novel markers among which ryanodine receptor seems to be a promising one, while the functional P2X7 receptor may serve as a therapeutic target. We have determined the tyrosine kinase "kinome" profile of HER-2-amplified breast cancers. Furthermore, the "kinome" profile was found to be characteristic for head and neck cancers of various anatomical location. Based on previous studies on the anti-migratory and antimetastatic potential of low-molecular-weight heparins, we have identified short heparin-derived oligosaccharides with maintained antimetastatic- but non-anticoagulant potentials. Pharmacogenomic studies on the role of polymorphism of the serine-hydroxymethyl-transferase (SHMT) gene in the efficacy of 5-FU and FOLFIRI protocols of colorectal cancer patients revealed a significant effect resulting in altered overall survival as well.     

Regulation of Epidermal Growth Factor Receptor Signaling and Erlotinib Sensitivity in Head and Neck Cancer Cells by miR-7

Elevated expression and activity of the epidermal growth factor receptor (EGFR)/protein kinase B (Akt) signaling pathway is associated with development, progression and treatment resistance of head and neck cancer (HNC). Several studies have demonstrated that microRNA-7 (miR-7) regulates EGFR expression and Akt activity in a range of cancer cell types via its specific interaction with the EGFR mRNA 3′-untranslated region (3′-UTR). In the present study, we found that miR-7 regulated EGFR expression and Akt activity in HNC cell lines, and that this was associated with reduced growth in vitro and in vivo of cells (HN5) that were sensitive to the EGFR tyrosine kinase inhibitor (TKI) erlotinib (Tarceva). miR-7 acted synergistically with erlotinib to inhibit growth of erlotinib-resistant FaDu cells, an effect associated with increased inhibition of Akt activity. Microarray analysis of HN5 and FaDu cell lines transfected with miR-7 identified a common set of downregulated miR-7 target genes, providing insight into the tumor suppressor function of miR-7. Furthermore, we identified several target miR-7 mRNAs with a putative role in the sensitization of FaDu cells to erlotinib. Together, these data support the coordinate regulation of Akt signaling by miR-7 in HNC cells and suggest the therapeutic potential of miR-7 alone or in combination with EGFR TKIs in this disease.     

Meta-analyses of the effect of cytochrome P450 2E1 gene polymorphism on the risk of head and neck cancer

Many studies have investigated the association between the CYP2E1 5′-flanking region (RsaI/PstI) polymorphism and head and neck cancer susceptibility, but the results were conflicting. In this meta-analysis, we assessed 24 published studies involving 12,562 subjects of the association between CYP2E1 RsaI/PstI polymorphism and head and neck cancer risk. Using the fixed effects model, we found significant association between PstI/RsaI polymorphism and head and neck cancer risk [OR = 1.11 (95%CI: 1.00–1.22) for c2 allele (P = 0.04) and OR = 1.57 (95% CI: 1.14–2.15) for c2 homozygous (P = 0.006) compared with wild type homozygote]. Significant results were also found in East Asians and Mix populations when stratified by ethnicity. However, no significant associations were found for Caucasians in all genetic models. Stratified analyses according to source of controls, significant associations were found only in hospital base controls. In the subgroup analyses by tumor types, significant association was detected only in oral cancer group, while no significant associations among laryngeal- or pharyngeal- cancer subgroup. This meta-analysis suggests that the CYP2E1 RsaI/PstI polymorphism may be a risk factor for head and neck cancer in Asians and Mix population, and that different carcinogenic processes involved in the genesis of various tumor types may exist.     

Role of DNA methylation in head and neck cancer

Head and neck cancer (HNC) is a heterogenous and complex entity including diverse anatomical sites and a variety of tumor types displaying unique characteristics and different etilogies. Both environmental and genetic factors play a role in the development of the disease, but the underlying mechanism is still far from clear. Previous studies suggest that alterations in the genes acting in cellular signal pathways may contribute to head and neck carcinogenesis. In cancer, DNA methylation patterns display specific aberrations even in the early and precancerous stages and may confer susceptibility to further genetic or epigenetic changes. Silencing of the genes by hypermethylation or induction of oncogenes by promoter hypomethylation are frequent mechanisms in different types of cancer and achieve increasing diagnostic and therapeutic importance since the changes are reversible. Therefore, methylation analysis may provide promising clinical applications, including the development of new biomarkers and prediction of the therapeutic response or prognosis. In this review, we aimed to analyze the available information indicating a role for the epigenetic changes in HNC.     

Type I collagen-mediated proliferation of PC3 prostate carcinoma cell line: implications for enhanced growth in the bone microenvironment.

Prostate cancer is the second leading cause of male cancer-related deaths in the United States. Interestingly, prostate cancer preferentially metastasizes to bone. Once in the bone microenvironment, advanced prostate cancer becomes highly resistant to therapeutic modalities. Several factors, such as, extracelluar matrix components, have been implicated in the spread and propagation of prostatic carcinoma. The prostate cell line, PC3, adhere and spread on collagen I to a greater degree than on fibronectin (FN) or poly-L-lysine (PLL). Flow cytometry analysis reveals the presence of the alpha(1), alpha(2) and alpha(3) collagen binding integrin subunits. Antibody function blocking studies reveal that PC3 cells can utilize alpha(2)beta(1) and alpha(3)beta(1) integrins to adhere to collagen I. Cells plated on collagen I exhibit increased rates of proliferation over cells plated on FN or tissue culture plastic. Additionally, cells plated on collagen I show increased expression of cyclin D1, a molecule associated with progression through G1 phase of the cell cycle. Inhibitor studies point to a role for phosphatidylinositol 3-kinase (PI3K), map kinase (MAPK) and p70 S6 kinase in collagen I-mediated PC3 cell proliferation and cyclin D1 expression. Type I collagen may facilitate the colonization and growth of metastatic prostate tumor cells in the bone microenvironment.     

Highly upregulated in liver cancer (HULC): An update on its role in carcinogenesis

Highly upregulated in liver cancer (HULC) was initially recognized during the screening of a hepatocellular carcinoma (HCC)-specific gene library. Further studies demonstrated its aberrant upregulation in several other tumor types. The oncogenic roles of this long noncoding RNA (lncRNA) have been verified through expression studies as well as functional studies. Moreover, the results of knockdown experiments have indicated diminished carcinogenic effects of cancer cell line in nude mice following HULC silencing. More recent studies have shown that expression levels of this lncRNA might be used as diagnostic biomarkers in cancer patients. Moreover, mechanistical studies have revealed associations between HULC and two HCC-related viruses namely hepatitis B and C viruses. Taken together, HULC can be regarded as a therapeutic target not only for HCC but also for a variety of human malignancies. In the current review, we summarized the recent literature about the role of HULC in the carcinogenesis and its potential application in cancer diagnosis and prognosis.     

Humoral immune response induced by an engineered cell-based neuroblastoma vaccine with or without CD25 blockade

Neuroblastoma is the most common extracranial solid cancer in childhood and it can develop in the nerve tissue of the adrenal gland, neck, chest, or spinal cord. A number of tumor-associated antigens (TAAs), which can elicit humoral immunity, have been identified in cancer patients. To investigate the humoral immunity during neuroblastoma development, we treated A/J mice with an aggressive clone of neuroblastoma (AGN2a) cells, then vaccinated the mice with cells expressing AGN2a-CD80/CD137L under the conditions with or without regulatory T cell blockade. Strong humoral immunity was induced by AGN2a-CD80/CD137L immunization in the context of regulatory T cell blockade. Sera from treated mice were used to screen an AGN2a cDNA expression library for identifying TAAs by SEREX (serological analysis of recombinant cDNA expression libraries). Clones were identified by sequencing and comparative analysis of gene pools. Further investigation of these gene products revealed that most of them play a role in the neuronal differentiation, cell metabolism, and are highly expressed in other types of malignancy. Asz1 (ankyrin repeat, SAM, and basic leucine zipper domain-containing protein) was found in all tumor-bearing groups. These results implicated that these candidates identified from tumor-bearing mice may be neuroblastoma-associated antigens, which can be used as biomarkers in early diagnosis of neuroblastoma, whereas those identified from vaccinated mice may be the potential therapeutic targets.     

The emerging role of the COP9 signalosome in cancer

In the last several years, multiple lines of evidence have suggested that the COP9 signalosome (CSN) plays a significant role in the regulation of multiple cancers and could be an attractive target for therapeutic intervention. First, the CSN plays a key role in the regulation of Cullin-containing ubiquitin E3 ligases that are central mediators of a variety of cellular functions essential during cancer progression. Second, several studies suggest that the individual subunits of the CSN, particularly CSN5, might regulate oncogenic and tumor suppressive functions independently of, or coordinately with, the CSN holocomplex. Thus, deregulation of CSN subunit function can have a dramatic effect on diverse cellular functions, including the maintenance of DNA fidelity, cell cycle control, DNA repair, angiogenesis, and microenvironmental homeostasis that are critical for tumor development. Additionally, clinical studies have suggested that the expression or localization of some CSN subunits correlate to disease progression or clinical outcome in a variety of tumor types. Although the study of CSN function in relation to tumor progression is in its infancy, this review will address current studies in relation to cancer initiation, progression, and potential for therapeutic intervention.     

EphA3 maintains radioresistance in head and neck cancers through epithelial mesenchymal transition

Radiotherapy is a well-established therapeutic modality used in the treatment of many cancers. However, radioresistance remains a serious obstacle to successful treatment. Radioresistance can cause local recurrence and distant metastases in some patients after radiation treatment. Thus, many studies have attempted to identify effective radiosensitizers. Eph receptor functions contribute to tumor development, modulating cell-cell adhesion, invasion, neo-angiogenesis, tumor growth and metastasis. However, the role of EphA3 in radioresistance remains unclear. In the current study, we established a stable radioresistant head and neck cancer cell line (AMC HN3R cell line) and found that EphA3 was expressed predominantly in the radioresistant head and neck cancer cell line through DNA microarray, real time PCR and Western blotting. Additionally, we found that EphA3 was overexpressed in recurrent laryngeal cancer specimens after radiation therapy. EphA3 mediated the tumor invasiveness and migration in radioresistant head and neck cancer cell lines and epithelial mesenchymal transition- related protein expression. Inhibition of EphA3 enhanced radiosensitivity in the AMC HN 3R cell line in vitro and in vivo study. In conclusion, our results suggest that EphA3 is overexpressed in radioresistant head and neck cancer and plays a crucial role in the development of radioresistance in head and neck cancers by regulating the epithelial mesenchymal transition pathway.