FGF-3 and FGF-4 elicit distinct oncogenic properties in mouse mammary myoepithelial cells

Targeting a cell surface vitamin D receptor on tumor-associated macrophages in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive tumor with limited treatment options and poor prognosis. We applied the in vivo phage display technology to isolate peptides homing to the immunosuppressive cellular microenvironment of TNBC as a strategy for non-malignant target discovery. We identified a cyclic peptide (CSSTRESAC) that specifically binds to a vitamin D receptor, protein disulfide-isomerase A3 (PDIA3) expressed on the cell surface of tumor-associated macrophages (TAM), and targets breast cancer in syngeneic TNBC, non-TNBC xenograft, and transgenic mouse models. Systemic administration of CSSTRESAC to TNBC-bearing mice shifted the cytokine profile toward an antitumor immune response and delayed tumor growth. Moreover, CSSTRESAC enabled ligand-directed theranostic delivery to tumors and a mathematical model confirmed our experimental findings. Finally, in silico analysis showed PDIA3-expressing TAM in TNBC patients. This work uncovers a functional interplay between a cell surface vitamin D receptor in TAM and antitumor immune response that could be therapeutically exploited.

Selection of phage-displayed accessible recombinant targeted antibodies (SPARTA): methodology and applications

We developed a potentially novel and robust antibody discovery methodology, termed selection of phage-displayed accessible recombinant targeted antibodies (SPARTA). This combines an in vitro screening step of a naive human antibody library against known tumor targets, with in vivo selections based on tumor-homing capabilities of a preenriched antibody pool. This unique approach overcomes several rate-limiting challenges to generate human antibodies amenable to rapid translation into medical applications. As a proof of concept, we evaluated SPARTA on 2 well-established tumor cell surface targets, EphA5 and GRP78. We evaluated antibodies that showed tumor-targeting selectivity as a representative panel of antibody-drug conjugates (ADCs) and were highly efficacious. Our results validate a discovery platform to identify and validate monoclonal antibodies with favorable tumor-targeting attributes. This approach may also extend to other diseases with known cell surface targets and affected tissues easily isolated for in vivo selection.

Ectodysplasin target gene Fgf20 regulates mammary bud growth and ductal invasion and branching during puberty

Mammary gland development begins with the appearance of epithelial placodes that invaginate, sprout, and branch to form small arborized trees by birth. The second phase of ductal growth and branching is driven by the highly invasive structures called terminal end buds (TEBs) that form at ductal tips at the onset of puberty. Ectodysplasin (Eda), a tumor necrosis factor-like ligand, is essential for the development of skin appendages including the breast. In mice, Eda regulates mammary placode formation and branching morphogenesis, but the underlying molecular mechanisms are poorly understood. Fibroblast growth factor (Fgf) receptors have a recognized role in mammary ductal development and stem cell maintenance, but the ligands involved are ill-defined. Here we report that Fgf20 is expressed in embryonic mammary glands and is regulated by the Eda pathway. Fgf20 deficiency does not impede mammary gland induction, but compromises mammary bud growth, as well as TEB formation, ductal outgrowth and branching during puberty. We further show that loss of Fgf20 delays formation of Eda-induced supernumerary mammary buds and normalizes the embryonic and postnatal hyperbranching phenotype of Eda overexpressing mice. These findings identify a hitherto unknown function for Fgf20 in mammary budding and branching morphogenesis.

Towards a transcriptome-based theranostic platform for unfavorable breast cancer phenotypes

Inflammatory breast carcinoma (IBC) is one of the most lethal forms of human breast cancer, and effective treatment for IBC is an unmet clinical need in contemporary oncology. Tumor-targeted theranostic approaches are emerging in precision medicine, but only a few specific biomarkers are available. Here we report up-regulation of the 78-kDa glucose-regulated protein (GRP78) in two independent discovery and validation sets of specimens derived from IBC patients, suggesting translational promise for clinical applications. We show that a GRP78-binding motif displayed on either bacteriophage or adeno-associated virus/phage (AAVP) particles or loop-grafted onto a human antibody fragment specifically targets orthotopic IBC and other aggressive breast cancer models in vivo. To evaluate the theranostic value, we used GRP78-targeting AAVP particles to deliver the human Herpes simplex virus thymidine kinase type-1 (HSVtk) transgene, obtaining simultaneous in vivo diagnosis through PET imaging and tumor treatment by selective activation of the prodrug ganciclovir at tumor sites. Translation of this AAVP system is expected simultaneously to image, monitor, and treat the IBC phenotype and possibly other aggressive (e.g., invasive and/or metastatic) subtypes of breast cancer, based on the inducible cell-surface expression of the stress-response chaperone GRP78, and possibily other cell-surface receptors in human tumors.

Association of a FGFR-4 gene polymorphism with bronchopulmonary dysplasia and neonatal respiratory distress

Background. Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease of premature birth, characterized by impaired alveolar development and inflammation. Pathomechanisms contributing to BPD are poorly understood. However, it is assumed that genetic factors predispose to BPD and other pulmonary diseases of preterm neonates, such as neonatal respiratory distress syndrome (RDS). For association studies, genes upregulated during alveolarization are major candidates for genetic analysis, for example, matrix metalloproteinases (MMPs) and fibroblast growth factors (FGFs) and their receptors (FGFR). Objective. Determining genetic risk variants in a Caucasian population of premature neonates with BPD and RDS. Methods. We genotyped 27 polymorphisms within 14 candidate genes via restriction fragment length polymorphism (RFLP): MMP-1, -2, -9, and -12, -16, FGF receptors 2 and 4, FGF-2, -3, -4, -7, and -18, Signal-Regulatory Protein α (SIRPA) and Thyroid Transcription Factor-1 (TTF-1). Results. Five single nucleotide polymorphisms (SNPs) in MMP-9, MMP-12, FGFR-4, FGF-3, and FGF-7 are associated (P < 0.05) with RDS, defined as surfactant application within the first 24 hours after birth. One of them, in FGFR-4 (rs1966265), is associated with both RDS (P = 0.003) and BPD (P = 0.023). Conclusion. rs1966265 in FGF receptor 4 is a possible genetic key variant in alveolar diseases of preterm newborns.

Upregulation of miR-31* is negatively associated with recurrent/newly formed oral leukoplakia

BACKGROUND

Oral leukoplakia (OLK) is a potentially malignant disorder of the oral cavity. However, the underlying mechanism of OLK is still unclear. In this study, we explore possible miRNAs involved in OLK.

METHODOLOGY/PRINCIPAL FINDINGS

Using miRNA microarrays, we profiled miRNA expression in OLK and malignantly transformed OLK (mtOLK) tissue samples. The upregulation of miR-31*, miR-142-5p, miR-33a, miR-1259, miR-146b-5p, miR-886-3p, miR-886-5p, miR-519d, and miR-301a along with the downregulation of miR-572, miR-611, miR-602, miR-675, miR-585, miR-623, miR-637, and miR-1184 in mtOLK were new observations. Fluorescence in situ hybridization (FISH) analyses confirmed that miR-31* is highly expressed in mtOLK. There was a significant difference between the FISH score (p<0.05) in patients with or without recurrent/newly formed OLK. Functional analyses demonstrated that a miR-31* inhibitor decreased apoptosis in the Leuk-1, which is an immortalized oral epithelial cell line spontaneously derived from an oral leukoplakia lesion. miR-31* regulated apoptosis, cell proliferation, migration, and invasion in the HOIEC, which is a HPV E6/E7-immortalized oral epithelial cell line. Furthermore, miR-31* modulated the biological functions of apoptosis, cell proliferation, cell cycle, migration, and invasion in the oral squamous cell carcinoma cell line, Cal-27. Using bioinformatic analyses and dual luciferase reporter assays, we determined that the 3' untranslated region of fibroblast growth factor 3 (FGF3) is the target of miR-31*. Expression of FGF3 was downregulated or upregulated in the presence of a miR-31* mimic or inhibitor, respectively.

CONCLUSIONS/SIGNIFICANCE

Upregulation of miR-31* is negatively associated with recurrent/newly formed OLK. MiR-31* may exert similar but distinguishable effects on biological function in oral cells with different malignant potential. FGF3 is the target of miR-31*. miR-31* may play an important role during OLK progression through regulating FGF3. MiRNA* strands may also have prominent roles in oral carcinogenesis.

Antitumor activity of SNX-2112, a synthetic heat shock protein-90 inhibitor, in MET-amplified tumor cells with or without resistance to selective MET Inhibition

PURPOSE

Heat shock protein-90 (HSP-90), a molecular chaperone required by numerous oncogenic kinases [e.g., HER-2, epidermal growth factor receptor (EGFR), Raf-1, v-Src, and AKT] for conformational stability, has attracted wide interest as a novel target for cancer therapy. HSP-90 inhibition induces degradation of HSP-90 client proteins, leading to a combinatorial inhibition of multiple oncogenic signaling pathways with consecutive growth arrest and apoptosis. MET, a tyrosine kinase that is constitutively active in tumor cells with MET oncogene amplification, has recently been identified as another HSP-90 client.

EXPERIMENTAL DESIGN

The aim of our study was to assess the efficacy of SNX-2112, a synthetic HSP-90 inhibitor, in 3 different MET-amplified tumor cell lines (GTL-16, MKN-45, and EBC-1) as well as PR-GTL-16 cells, a GTL-16 subline selected for resistance to the highly selective MET kinase inhibitor PHA-665752.

RESULTS

In all cell lines, SNX-2112 led to degradation of MET, HER-2, EGFR, and AKT, as well as abrogation of Ras/Raf/MEK/MAPK and PI3K/AKT signaling, followed by complete cell cycle arrest. SNX-5542, an orally bioavailable prodrug of SNX-2112, displayed significant antitumor efficacy in vivo in nude mice bearing MET-amplified tumor xenografts. Importantly, HSP-90 inhibition maintained its antitumor efficacy in PR-GTL-16 cells both in vitro and in vivo, suggesting that HSP-90 inhibition could be a particularly valuable strategy in MET-amplified tumors that have acquired resistance to MET kinase inhibition.

CONCLUSIONS

Our study provides evidence for the efficacy of HSP-90 inhibition in MET-amplified cancer cells, particularly when MET kinase inhibitor resistance has emerged.

Targeted filamentous bacteriophages as therapeutic agents

Bacteriophages (phages) have been used for therapy of bacterial infections, for genetic research, as tools for the discovery of specific target binding proteins and for vaccine development. The aim of this article is to present advances in genetic and chemical engineering of filamentous bacteriophages that facilitated their application for therapeutic purposes. We review studies where phages were applied for in vivo imaging, as gene delivery vehicles and as drug carriers. Target specificity is based on peptides or proteins displayed on the phage coat. The cargo may be a packaged gene incorporated into the phage genome for gene delivery applications, or imaging agents or cytotoxic drugs chemically conjugated at high density onto the phage coat. We believe that the combination of those separately developed methodologies would result in clinical applications of phage-based therapeutics.

ArrayCGH-based classification of neuroblastoma into genomic subgroups

High-resolution array comparative genomic hybridization (arrayCGH) profiling was performed on 75 primary tumors and 29 cell lines to gain further insight into the genetic heterogeneity of neuroblastoma and to refine genomic subclassification. Using a novel data-mining strategy, three major and two minor genomic subclasses were delineated. Eighty-three percent of tumors could be assigned to the three major genomic subclasses, corresponding to the three known clinically and biologically relevant subsets in neuroblastoma. The remaining subclasses represented (1) tumors with no/few copy number alterations or an atypical pattern of aberrations and (2) tumors with 11q13 amplification. Inspection of individual arrayCGH profiles showed that recurrent genomic imbalances were not exclusively associated with a specific subclass. Of particular notice were tumors with numerical imbalances typically observed in subtype 1 neuroblastoma, in association with genomic features of subtype 2A or 2B. A search for prognostically relevant genomic alterations disclosed 1q gain as a predictive marker for therapy failure within the group of subtype 2A and 2B tumors. In cell lines, a high incidence of 6q loss was observed, with a 3.87-5.32 Mb region of common loss within 6q25.1-6q25.2. Our study clearly illustrates the importance of genomic profiling in relation to tumor behavior in neuroblastoma. We propose that genome-wide assessment of copy number alterations should ideally be included in the genetic workup of neuroblastoma. Further multicentric studies on large tumor series are warranted in order to improve therapeutic stratification in conjunction with other features such as age at diagnosis, tumor stage, and gene expression signatures.

Up-regulation of fibroblast growth factor 3 is associated with tumor metastasis and recurrence in human hepatocellular carcinoma

Recently, we established a hepatocellular carcinoma (HCC) cell line (named H4-M) from a metastatic HCC tumor. In H4-M, a marker chromosome containing a homogeneously staining region (hsr) was identified by cytogenetic analysis. The hsr was characterized by chromosome microdissection and the result showed that the hsr was composed of DNA sequence from 11q13. Oncogenes CCND1 and FGF3 were localized within the complicon and overexpressions of CCND1 and FGF3 were confirmed by Northern blot analysis. Clinical significance of FGF3 overexpression was studied by immunohistochemistry (IHC) using an HCC tissue microarray (TMA) containing 60 pairs of primary/metastatic HCCs and 30 pairs of primary/recurrent HCCs. TMA study showed that overexpression of FGF3 was significantly associated with HCC metastasis and recurrence (p<0.01), suggesting that up-regulation of FGF3 may play an important role in HCC metastasis and recurrence.

A novel gene STYK1/NOK is upregulated in estrogen receptor-alpha negative estrogen receptor-beta positive breast cancer cells following estrogen treatment

The human STYK1/NOK protein is approximately 30-35% similar to mouse fibroblast growth factor receptor 3 and a kinase homologue in D. melanogaster in the tyrosine protein kinase region. STYK1/NOK was identified as being up regulated in MDA-MB-231, an estrogen receptor-alpha negative breast cancer cell line, following 12 h of estrogen treatment at 1x10(-9) M. On further investigation of STYK1/NOK in estrogen treated cell line MDA-MB-231, STYK1/NOK was up regulated at 6 h post treatment when compared to untreated cells. We also investigated the expression levels of STYK1/NOK in other breast cancer cell lines MCF-7, MDA-MB-231, BT-549, and MDA-MB-435S using QRT-PCR. In addition, the analysis of message accumulation was increased with other synthetic estrogen response modifiers. We propose that the regulation of STYK1/NOK is achieved independent of ERalpha and suggests further investigation to the relevance of this kinase in breast cancer progression.

High-resolution analysis of allelic imbalance in neuroblastoma cell lines by single nucleotide polymorphism arrays

Genomic copy number changes are detectable in many malignancies, including neuroblastoma, using techniques such as comparative genomic hybridization (CGH), microsatellite analysis, conventional karyotyping, and fluorescence in situ hybridization (FISH). We report the use of 10K single nucleotide polymorphism (SNP) microarrays to detect copy number changes and allelic imbalance in six neuroblastoma cell lines (IMR32, SHEP, NBL-S, SJNB-1, LS, and SKNBE2c). SNP data were generated using the GeneChip DNA Analysis and GeneChip chromosome copy number software (Affymetrix). SNP arrays confirmed the presence of all previously reported cytogenetic abnormalities in the cell lines, including chromosome 1p deletion, MYCN amplification, gain of 17q and 11q, and 14q deletions. In addition, the SNP arrays revealed several chromosome gains and losses not detected by CGH or karyotyping; these included gain of 8q21.1 approximately 24.3 and gain of chromosome 12 in IMR-32 cells; loss at 4p15.3 approximately 16.1 and loss at 16p12.3 approximately 13.2, 11q loss with loss of heterozygosity (LOH) at 11q14.3 approximately 23.3 in SJNB-1 cells; and loss at 8p21.2 approximately 23.3 and 9p21.3 approximately 22.1 with corresponding LOH in SHEP cells. The SNP arrays refined the mapping of the 2p amplicons in LS, BE2c, and IMR-32 cell lines, the 12q amplicon in LS cells, and also identified an 11q13 amplicon in LS cells. There was good concordance among SNP arrays, CGH, and karyotyping. SNP array analysis is a powerful tool for the detection of allelic imbalance in neuroblastoma and also allows identification of LOH without changes in copy number (uniparental disomy).

Array-comparative genomic hybridization to detect genomewide changes in microdissected primary and metastatic oral squamous cell carcinomas

Oral squamous cell carcinoma (OSCC) is a common worldwide malignancy. However, it is unclear what, if any, genomic alterations occur as the disease progresses to invasive and metastatic OSCC. This study used genomewide array-CGH in microdissected specimens to map genetic alterations found in primary OSCC and neck lymph node metastases. We used array-based comparative genomic hybridization (array-CGH) to screen genomewide alterations in eight pairs of microdissected tissue samples from primary and metastatic OSCC. In addition, 25 primary and metastatic OSCC tissue pairs were examined with immunohistochemistry for protein expression of the most frequently altered genes. The highest frequencies of gains were detected in LMYC, REL, TERC, PIK3CA, MYB, MDR1, HRAS, GARP, CCND2, FES, HER2, SIS, and SRY. The highest frequencies of losses were detected in p44S10, TIF1, LPL, MTAP, BMI1, EGR2, and MAP2K5. Genomic alterations in TGFbeta2, cellular retinoid-binding protein 1 gene (CRBP1), PIK3CA, HTR1B, HRAS, ERBB3, and STK6 differed significantly between primary OSCC and their metastatic counterparts. Genomic alterations in PRKCZ, ABL1, and FGF4 were significantly different in patients who died compared with those who survived. Immunohistochemistry confirmed high PIK3CA immunoreactivity in primary and metastatic OSCC. Higher FGF4 immunoreactivity in primary OSCC is associated with a worse prognosis. Loss of CRBP1 immunoreactivity is evident in primary and metastatic OSCC. Our study suggests that precise genomic profiling can be useful in determining gene number changes in OSCC. As our understanding of these changes grow, this profiling may become a practical tool for clinical evaluation.

Valine-based biphenylsulphonamide matrix metalloproteinase inhibitors as tumor imaging agents

Among matrix metalloproteinases (MMPs), the subfamily of gelatinases (MMP-2, MMP-9) is of particular interest due to their ability to degrade type IV collagen and other non-fibrillar collagen domains and proteins such as fibronectin and laminin. Whilst malignant cells often over-express various MMPs, the gelatinases have been most consistently detected in malignant tissues and associated with tumor growth, metastatic potential and angiogenesis. Radiosynthesis of carboxylic (1') and hydroxamic (2') MMPIs resulted in radiochemical yields of 70 +/- 5% (n = 6) and 60 +/- 5% (n = 4), respectively. Evaluation in A549-inoculated athymic mice showed a tumor uptake of 2. 0+/- 0.7%ID/g (3 h p.i.), a tumor/blood ratio of 0.5 and a tumor/muscle ratio of 4.6 at 48 h p.i. for 1'. For compound 2' a tumor uptake of 0.7 +/- 0.2%ID/g (3 h p.i.), a tumor/blood ratio of 1.2 and a tumor/muscle ratio of 1.8 at 24 h p.i. were observed. HPLC analysis of the blood (plasma) showed no dehalogenation or other metabolites of 1' 2 h p.i. For compound 2', 65.4% of intact compound was found in the blood (plasma) and one polar metabolite (31%) was detected whereas in the tumor 91.8% of the accumulated activity was caused by intact compound and only 8.1% by the metabolite. Planar imaging, using a Toshiba GCA-9300A/hg SPECT camera, showed that tumor tissue could be visualized and that image quality improved by decreasing specific activity resulting in lower liver uptake, indicating some degree of saturable binding in the liver. In vivo evaluation of these radioiodinated carboxylic and hydroxamic MMP inhibitor tracers revealed that MMP inhibitors could have potential as tumor imaging agents, but that further research is necessary.

Tryptophane-Based Biphenylsulfonamide Matrix Metalloproteinase Inhibitors as Tumor Imaging Agents

AIM

As a part of our efforts to use small organic matrix metalloproteinase (MMP) inhibitors with improved characteristics for the diagnosis and treatment of different kinds of tumor tissues, biphenylsulfonamide analogues were synthesized. This study reports on the in vivo biodistribution of iodine-123-labeled biphenylsulfonide and analogues in A549 lung carcinoma inoculated into athymic mice and the evaluation of their suitability as imaging agents using a single photon emission computed tomography (SPECT) camera.

METHODS

The radioiodinated carboxylic and hydroxamic MMP inhibitors 2-(4'- [(123)I]iodobiphenyl-4-sulfonylamino)-3-(1H-indol-3-yl)-propionic acid (1') and 2-(4'-[(123)I]iodobiphenyl-4- sulfonylamino)-3-(1H-indol-3-yl)-propionamide (2') were synthesized by electrophilic aromatic substitution of the tributylstannyl derivatives. Planar gamma camera imaging was performed in nu/nu athymic mice bearing an A549 tumor using a Toshiba GCA-9300A/hg SPECT camera in planar mode equipped with a high-resolution, parallel-hole collimator.

RESULTS

Radiosynthesis of (1') and (2') resulted in radiochemical yields of 60 +/- 5% (n +/- 3) and 70 +/- 5% (n = 6), respectively. Evaluation of tumors induced in athymic mice by the inoculation of non-small cell lung A549 carcinoma cells, showed a tumor uptake of 0.27-0.01 percent injected dose per gram (%ID/g) (3 hours-48 hours p.i.), a tumor-blood ratio of 0.7, a tumor-muscle ratio of 1.6, and a tumor-fat ratio of 0.5 at 24 hours (p.i.) for compound 1'. For compound 2' a tumor uptake of 0.7-0.04 %ID/g (3 hours-48 hours p.i.), a postinjection tumor-blood ratio of 1.2, a tumor-muscle ratio of 3.2, and a tumor-fat ratio of 2.4 at 48 hours p.i. was observed. SPECT evaluation confirmed the results obtained from biodistribution.

CONCLUSION

In vivo evaluation of these radioiodinated carboxylic and hydroxamic MMP inhibitor tracers revealed that they do not appear suitable as tumor-imaging agents.

Design and validation of a bifunctional ligand display system for receptor targeting

Here we developed a bacteriophage display particle designed to serve as a bifunctional entity that can target tumors while delivering an agent. We engineered a chimera phage vector containing a pIII-displayed alphav integrins-targeting moiety and a pVIII-displayed streptavidin binding adaptor moiety. By using the chimeric phage particle, targeting of alphav integrins on cells in culture and tumor-related blood vessels was shown through different applications, including luminescent quantum dots localization, surface plasmon resonance-based binding detection, and an in vivo tumor model. The strategy validated here will accelerate the discovery and characterization of receptor-ligand binding events in high throughput, and cell-specific delivery of diagnostics or therapeutics to organs of choice without the need for chemical conjugation.

Combinatorial Screenings in Patients

Direct screening of combinatorial peptide libraries in patients may allow the identification of ligands that target biochemical differences in the endothelium of blood vessels. In a screening performed in a patient, we selected and isolated a mimic motif of interleukin 11 (IL-11) from prostate biopsies after an i.v. administration of a phage display peptide library. We also demonstrated that the IL-11 phage mimic (displaying the cyclic nonapeptide CGRRAGGSC) bound specifically to a corresponding IL-11 receptor (IL-11Ralpha). Here we show that IL-11Ralpha is a potential target for intervention in human prostate cancer through morphological and functional analyses. First, a comprehensive serial immunohistochemical analysis of primary and metastatic prostate cancer samples showed increased stage-specific expression of IL-11Ralpha during disease progression. Second, a proapoptotic peptide was specifically targeted and internalized through this functional IL-11Ralpha-based ligand-receptor pair: treatment of prostate cancer cells in vitro with a proapoptotic peptide guided by the CGRRAGGSC peptide to the IL-11Ralpha resulted in dose-dependent apoptosis. Together, these data indicate that the IL-11Ralpha is a candidate target for translational clinical trials against advanced and metastatic prostate cancer. Moreover, our results illustrate the ability of direct combinatorial screening systems in cancer patients for identification of relevant targets in the context of human disease.

Plasmin‐activated doxorubicin prodrugs containing a spacer reduce tumor growth and angiogenesis without systemic toxicity

To generate doxorubicin (Dox) specifically at the tumor site, the chemotherapeutic agent was incorporated into a prodrug by linkage to a peptide specifically recognized by plasmin, which is overproduced in many cancers. ST-9905, which contains an elongated self-elimination spacer, is activated more rapidly in vitro by plasmin than is ST-9802. Prodrug activation in vitro depended on the level of urokinase produced by tumor cells and was inhibited by aprotinin, a plasmin inhibitor. Comparison of equimolar concentrations of ST-9905, ST-9802, and Dox in EF43.fgf-4 and MCF7 models revealed that both prodrugs, in sharp contrast to Dox, displayed antiproliferative and antiangiogenic activities without discernible toxicity. Although MCF7 cells are poor urokinase producers in vitro, prodrug efficacy in this model may be explained by production of plasmin by tumor-infiltrating host cells. Mice treated with equitoxic concentrations (maximum tolerated doses) of prodrugs showed 100% survival and negligible body weight loss, in contrast to results after Dox treatment. ST-9905 was substantially more effective than ST-9802 and induced similar tumor growth inhibition as Dox but without apparent toxicity. This finding may be explained by the elongated spacer, which facilitates enzymatic prodrug activation. These data validate both the use of elongated spacers in vivo and the concept of targeting anticancer prodrugs to tumor-associated plasmin.

Hepatoma-derived growth factor induces tumorigenesis in vivo through both direct angiogenic activity and induction of vascular endothelial growth factor

Hepatoma-derived growth factor (HDGF) is highly expressed in tumor cells, and stimulates their proliferation. In the present study, we investigated the role of HDGF in tumorigenesis and elucidated the mechanism of action. Stable transfectants of NIH3T3 cells overexpressing HDGF did not show significant anchorage-independent growth in soft agar assay. However, these stable transfectants overexpressing HDGF generated sarcomatous tumors in nude mice. These tumors were red-colored macroscopically, and histologically showed a rich vascularity. Immunohistochemical analysis using CD31 antibody showed new vessel formation. Recombinant HDGF stimulated proliferation of human umbilical vein endothelial cells in a dose-dependent manner, and stimulated tubule formation. Furthermore, vascular endothelial growth factor (VEGF) was detected immunohistochemically in the tumor tissues. Transient expression of HDGF induced both VEGF gene and protein expression as demonstrated by a reporter assay using VEGF gene promoter. The administration of anti-VEGF neutralizing antibody significantly suppressed, but did not block, the tumor growth of HDGF-overexpressing cells in nude mice. Thus, these findings suggested that HDGF-induced tumor formation in vivo involves induction of VEGF as well as direct angiogenic activity.

Wnt-1 and int-2 mammary oncogene effects on the beta-catenin pathway in immortalized mouse mammary epithelial cells are not sufficient for tumorigenesis

Development of strategies for prevention of breast cancer development requires an understanding of the effects of mammary oncogenes on mammary cells at early stages in neoplastic transformation. As mammary oncogenes wnt-1 and int-2 affect different signal transduction pathways, we investigated their effects on established mouse mammary epithelial cell lines (MMECLs) reflecting early stages in tumorigenesis. Normal interactions between beta-catenin and E-cadherin were abrogated in all three immortalized MMECLs and the cells lacked beta-catenin-mediated transactivation activity, detectable using a reporter assay, suggesting that alterations in cell adhesion may be very early events in mammary tumorigenesis. Immortalized FSK4 and EL12 cells and hyperplastic TM3 cells were stably transfected with expression vectors encoding wnt-1 or int-2 or the control vector, and drug-selected pooled cells from each line were confirmed by reverse transcription-polymerase chain reaction to express the transfected oncogene; this expression persisted in the cells analysed in vitro and in vivo. Resultant phenotypic changes depended both on the oncogene and the target mammary cell line. In FSK4 cells, expression of wnt-1 or int-2 resulted in proliferative changes in vitro, including reduced contact inhibition, increased beta-catenin expression, and decreased p53 transcriptional activity, but neither oncogene conferred upon those cells the ability to produce tumors in vivo. EL12 cells were highly refractory to the effects of both oncogenes, with the only measurable changes being increased E-cadherin levels induced by both oncogenes and increased proliferation of the int-2-transfected cells in the absence of serum. Parental TM3 cells were phenotypically similar to wnt-1- or int-2-transfected FSK4 cells and displayed an increased rate of proliferation in vitro and markedly increased tumorigenicity in vivo following transfection with int-2 but not with wnt-1. These results suggest that wnt-1 signaling is redundant in the hyperplastic TM3 cells and indicate that wnt-1-induced effects in the immortalized FSK4 and EL12 cells were not sufficient to mediate a tumorigenic phenotype. This study showed that the wnt-1 and int-2 oncogenes have similar but distinguishable effects on immortalized MMECLs and that the genetic background of the mammary cells greatly influences the consequences of oncogene expression at early stages of cell transformation.

Gene therapy for therapeutic angiogenesis in critically ischaemic lower limb - on the way to the clinic

Currently, no effective pharmacological treatment is available for vascularisation defects in lower limbs. Many patients presenting with persistent pain and ischaemic ulcers are not suitable candidates for surgical or endovascular approaches. Further refinement of the available methods will undoubtedly lead to a more active approach towards treatment of peripheral arterial occlusive disease (PAOD). Recently, therapeutic angiogenesis, in the form of recombinant growth factor administration or gene therapy, has emerged as a novel tool to treat these patients. However, improved gene transfer methods and better understanding of blood vessel formation are required to bring therapeutic angiogenesis to clinical practice. Here we review the clinical problem (PAOD), mechanisms of blood vessel formation (angiogenesis, vasculogenesis and arteriogenesis), experimental evidence and clinical trials for therapeutic angiogenesis in critically ischaemic lower limbs. Also, angiogenic growth factors, including vascular endothelial growth factors (VEGFs) and fibroblast growth factors (FGFs), delivery methods, and vectors for gene transfer in skeletal muscle, are discussed. In addition to vascular growth, gene transfer of growth factors may enhance regeneration, survival, and innervation of ischaemic skeletal muscle. Nitric oxide (NO) appears to be a key mediator in vascular homeostasis and growth, and a reduction in its production by age, hypercholesterolemia or diabetes leads to the impairment of ischaemic disorders.

Altered HOX and WNT7A expression in human lung cancer

HOX genes encode transcription factors that control patterning and cell fates. Alterations in HOX expression have been clearly implicated in leukemia, but their role in most other malignant diseases remains unknown. By using degenerate reverse transcription-PCR and subsequent real-time quantitative assays, we examined HOX expression in lung cancer cell lines, direct tumor-control pairs, and bronchial epithelial cultures. As in leukemia, genes of the HOX9 paralogous group and HOXA10 were frequently overexpressed. For HOXB9, we confirmed that elevated RNA was associated with protein overexpression. In some cases, marked HOX overexpression was associated with elevated FGF10 and FGF17. During development, the WNT pathway affects cell fate, polarity, and proliferation, and WNT7a has been implicated in the maintenance of HOX expression. In contrast to normal lung and mortal short-term bronchial epithelial cultures, WNT7a was frequently reduced or absent in lung cancers. In immortalized bronchial epithelial cells, WNT7a was lost concomitantly with HOXA1, and a statistically significant correlation between the expression of both genes was observed in lung cancer cell lines. Furthermore, we identified a homozygous deletion of beta-catenin in the mesothelioma, NCI-H28, associated with reduced WNT7a and the lowest overall cell line expression of HOXA1, HOXA7, HOXA9, and HOXA10, whereas HOXB9 levels were unaffected. Of note, both WNT7a and beta-catenin are encoded on chromosome 3p, which undergoes frequent loss of heterozygosity in these tumors. Our results suggest that alterations in regulatory circuits involving HOX, WNT, and possibly fibroblast growth factor pathways occur frequently in lung cancer.

Progression in MCF-7 breast cancer cell tumorigenicity: compared effect of FGF-3 and FGF-4

The transforming properties of fibroblast growth factor 3 (FGF-3) were investigated in MCF7 breast cancer cells and compared to those of FGF-4, a known oncogenic product. The short form of fgf-3 and the fgf-4 sequences were each introduced with retroviral vectors and the proteins were only detected in the cytoplasm of the infected cells, as expected. In vitro, cells producing FGF-3 (MCF7.fgf-3) and FGF-4 (MCF7.fgf-4) displayed an amount of estrogen receptors decreased to around 45% of the control value. However, MCF7.fgf-3 cell proliferation remained responsive to estradiol supply. The sensitivity of the MCF7.fgf-4 cells, if existant, was masked by the important mitogenic action exerted by FGF-4. In vivo, the MCF7.fgf-3 and MCF7.fgf-4 cells gave rise to tumors under conditions in which the control cells were not tumorigenic. Supplementing the mice with estrogen had the paradoxical effect of totally suppressing the start of the FGF-3 as well as the FGF-4 tumors. Tumorigenicity in the presence of matrigel was similar for MCF7.fgf-3 and control cells and was increased by estrogen supplementation. Once started, the MCF7.fgf-4 tumors grew with a characteristic high rate. Remarkably, FGF-4 but not FGF-3, stimulated the secretion of vascular endothelial growth factor (VEGF165) without altering the steady-state level of its mRNA, suggesting a possible regulation of VEGF synthesis at the translational level in MCF7 cells. The increased VEGF secretion is probably involved in the more aggressive phenotype of the MCF7.fgf-4 cells while a decreased dependence upon micro-environmental factors might be part of the increased tumorigenic potential of the MCF7.fgf-3 cells.