Anti-tumor angiogenesis therapy using soluble receptors: enhanced inhibition of tumor growth when soluble fibroblast growth factor receptor-1 is used with soluble vascular endothelial growth factor receptor

Ecoevolutionary biology of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC), the most common histological subtype of pancreatic cancer, is an aggressive disease predicted to be the 2nd cause of cancer mortality in the US by 2040. While first-line therapy has improved, 5-year overall survival has only increased from 5 to ∼10%, and surgical resection is only available for ∼20% of patients as most present with advanced disease, which is invariably lethal. PDAC has well-established highly recurrent mutations in four driver genes including KRAS, TP53, CDKN2A, and SMAD4. Unfortunately, these genetic drivers are not currently therapeutically actionable. Despite extensive sequencing efforts, few additional significantly recurrent and druggable drivers have been identified. In the absence of targetable mutations, chemotherapy remains the mainstay of treatment for most patients. Further, the role of the above driver mutations on PDAC initiation and early development is well-established. However, these mutations alone cannot account for PDAC heterogeneity nor discern early from advanced disease. Taken together, management of PDAC is an example highlighting the shortcomings of the current precision medicine paradigm. PDAC, like other malignancies, represents an ecoevolutionary process. Better understanding the disease through this lens can facilitate the development of novel therapeutic strategies to better control and cure PDAC. This review aims to integrate the current understanding of PDAC pathobiology into an ecoevolutionary framework.

Far beyond anti-angiogenesis: Benefits for anti-basicFGF therapy in cancer

Basic FGF (bFGF) was discovered as a typical inducer of angiogenesis and has already been studied for 3 decades. Recent evidence indicates that bFGF plays different roles and controls signaling pathways that participate in the hallmarks of cancer, underscoring bFGF an appealing target for anti-cancer therapy. However, the early clinical trials designed to block bFGF signaling showed safety without satisfiable benefits for cancer patients. In this review, we firstly discuss bFGF's canonical signaling pathways and later review newly identified bFGF's functions that contribute to the cancer hallmarks besides its typical role in angiogenesis. After, we summarize the role of bFGF as a therapeutic target in response to different cancer therapies including radiotherapy, chemotherapy, targeted therapy, immunotherapy, and highlight the difficulties we must solve regarding the design of drugs targeting specifically bFGF. We also emphasize the need, especially for natural bFGF traps, to deepen their molecular mechanisms of action considering the specific context of cancer with different FGFR status, as well as the urgence of stratifying patients for both anti-bFGF first line and second line anti-cancer therapy. Finally, a perspective on potential feed-forward oncogenic signaling pathways mediated by bFGF is made. We discuss the importance of developing additional robust biomarkers to select patients who will benefit from bFGF-targeted therapy, as well as the rationale of developing combinatory therapies targeting either bFGF and/or its intracellular (co)effectors. This would ultimately provide novel therapeutic strategies to fight cancer.

Markers of pancreatic cancer stem cells and their clinical and therapeutic implications

Pancreatic cancer (PC) is the fourth most common cause of death among all cancers. Poor prognosis of PC may be caused by a prevalence of cancer stem cells (CSCs). CSCs are a population of cancer cells showing stem cell-like characteristics. CSCs have the ability to self-renew and may initiate tumorigenesis. PC CSCs express markers such as CD133, CD24, CD44, DCLK1, CXCR4, ESA, Oct4 and ABCB1. There is a wide complexity of interaction and relationships between CSC markers in PC. These markers are negative prognostic factors and are connected with tumor recurrence and clinical progression. Additionally, PC CSCs are resistant to treatment with gemcitabine. Thus, most current therapies for PC are ineffective. Numerous studies have shown, that targeting of these proteins may increase both disease-free and overall survival in PC.

Gene Therapy for Pancreatic Cancer: Specificity, Issues and Hopes

A recent death projection has placed pancreatic ductal adenocarcinoma as the second cause of death by cancer in 2030. The prognosis for pancreatic cancer is very poor and there is a great need for new treatments that can change this poor outcome. Developments of therapeutic innovations in combination with conventional chemotherapy are needed urgently. Among innovative treatments the gene therapy offers a promising avenue. The present review gives an overview of the general strategy of gene therapy as well as the limitations and stakes of the different experimental in vivo models, expression vectors (synthetic and viral), molecular tools (interference RNA, genome editing) and therapeutic genes (tumor suppressor genes, antiangiogenic and pro-apoptotic genes, suicide genes). The latest developments in pancreatic carcinoma gene therapy are described including gene-based tumor cell sensitization to chemotherapy, vaccination and adoptive immunotherapy (chimeric antigen receptor T-cells strategy). Nowadays, there is a specific development of oncolytic virus therapies including oncolytic adenoviruses, herpes virus, parvovirus or reovirus. A summary of all published and on-going phase-1 trials is given. Most of them associate gene therapy and chemotherapy or radiochemotherapy. The first results are encouraging for most of the trials but remain to be confirmed in phase 2 trials.

Recent Advances and Prospects for Multimodality Therapy in Pancreatic Cancer

The outcomes for treatment of pancreatic cancer have not improved dramatically in many decades. However, the recent promising results with combination chemotherapy regimens for metastatic disease increase optimism for future treatments. With greater control of overt or occult metastatic disease, there will likely be an expanding role for local treatment modalities, especially given that nearly a third of pancreatic cancer patients have locally destructive disease without distant metastatic disease at the time of death. Technical advances have allowed for the safe delivery of dose-escalated radiation therapy, which can then be combined with chemotherapy, targeted agents, immunotherapy, and nanoparticulate drug delivery techniques to produce novel and improved synergistic effects. Here we discuss recent advances and future directions for multimodality therapy in pancreatic cancer.

Overview of pre-clinical and clinical studies targeting angiogenesis in pancreatic ductal adenocarcinoma

The importance of angiogenesis in pancreatic ductal adenocarcinoma (PDAC) and its therapeutic potential have been explored in both pre-clinical and clinical studies. Human PDACs overexpress a number of angiogenic factors and their cognate high-affinity receptors, and anti-angiogenic agents reduce tumor volume, metastasis, and microvessel density (MVD), and improve survival in subcutaneous and orthotopic pre-clinical models. Nonetheless, clinical trials using anti-angiogenic therapy have been overwhelmingly unsuccessful. This review will focus on these pre-clinical and clinical studies, the potential reasons for failure in the clinical setting, and ways these shortcomings could be addressed in future investigations of angiogenic mechanisms in PDAC.

TCGA data and patient-derived orthotopic xenografts highlight pancreatic cancer-associated angiogenesis

Pancreatic ductal adenocarcinomas (PDACs) overexpress pro-angiogenic factors but are not viewed as vascular. Using data from The Cancer Genome Atlas we demonstrate that a subset of PDACs exhibits a strong pro-angiogenic signature that includes 37 genes, such as HDAC9, that are overexpressed in PDAC arising in KRC mice, which express mutated Kras and lack RB. Moreover, patient-derived orthotopic xenografts can exhibit tumor angiogenesis, whereas conditioned media (CM) from KRC-derived pancreatic cancer cells (PCCs) enhance endothelial cell (EC) growth and migration, and activate canonical TGF-β signaling and STAT3. Inhibition of the type I TGF-β receptor with SB505124 does not alter endothelial activation in vitro, but decreases pro-angiogenic gene expression and suppresses angiogenesis in vivo. Conversely, STAT3 silencing or JAK1-2 inhibition with ruxolitinib blocks CM-enhanced EC proliferation. STAT3 disruption also suppresses endothelial HDAC9 and blocks CM-induced HDAC9 expression, whereas HDAC9 re-expression restores CM-enhanced endothelial proliferation. Moreover, ruxolitinib blocks mitogenic EC/PCC cross-talk, and suppresses endothelial p-STAT3 and HDAC9, and PDAC progression and angiogenesis in vivo, while markedly prolonging survival of KRC mice. Thus, targeting JAK1-2 with ruxolitinib blocks a final pathway that is common to multiple pro-angiogenic factors, suppresses EC-mediated PCC proliferation, and may be useful in PDACs with a strong pro-angiogenic signature.

Gene therapy in pancreatic cancer

Pancreatic cancer (PC) is a highly lethal disease and notoriously difficult to treat. Only a small proportion of PC patients are eligible for surgical resection, whilst conventional chemoradiotherapy only has a modest effect with substantial toxicity. Gene therapy has become a new widely investigated therapeutic approach for PC. This article reviews the basic rationale, gene delivery methods, therapeutic targets and developments of laboratory research and clinical trials in gene therapy of PC by searching the literature published in English using the PubMed database and analyzing clinical trials registered on the Gene Therapy Clinical Trials Worldwide website (http://www. wiley.co.uk/genmed/ clinical). Viral vectors are main gene delivery tools in gene therapy of cancer, and especially, oncolytic virus shows brighter prospect due to its tumor-targeting property. Efficient therapeutic targets for gene therapy include tumor suppressor gene p53, mutant oncogene K-ras, anti-angiogenesis gene VEGFR, suicide gene HSK-TK, cytosine deaminase and cytochrome p450, multiple cytokine genes and so on. Combining different targets or combination strategies with traditional chemoradiotherapy may be a more effective approach to improve the efficacy of cancer gene therapy. Cancer gene therapy is not yet applied in clinical practice, but basic and clinical studies have demonstrated its safety and clinical benefits. Gene therapy will be a new and promising field for the treatment of PC.

[Advanced research of fibroblast growth factor receptor in non-small cell lung cancer]

Lung cancer is severely threatening human health. In recent years, the treatment for lung adenocarcinoma has made a great progress, targeted therapy has been widely applied in clinic, and benefits amount of patients. However, in squamous cell lung cancer, the incidence of epidermal growth factor receptor (EGFR) gene mutant and ALK fusion gene are low,and targeted therapy like Tarceva and crizotinib, can hardly work. Since the fibroblast growth factors (fibroblast growth factor, FGF) pathway is considered to be related to tumor cell proliferation, metastasis and angiogenesis, more and more researches proved the amplification of fibroblast growth factor receptor (FGFR) in squamous cell lung cancer. Experiments in vivo and in vitro found that blocking FGF pathway could reduce the proliferation of tumor cells and inhibit metastasis. The FGF pathway might be a new target for treatment of squamous cell lung cancer. This article reviews the effect of FGFR in tumorigenesis,as well as the prospect as a therapeutic target in non-small cell lung cancer.

DCLK1 regulates pluripotency and angiogenic factors via microRNA-dependent mechanisms in pancreatic cancer

Stem cell pluripotency, angiogenesis and epithelial-mesenchymal transition (EMT) have been shown to be significantly upregulated in pancreatic ductal adenocarcinoma (PDAC) and many other aggressive cancers. The dysregulation of these processes is believed to play key roles in tumor initiation, progression, and metastasis, and is contributory to PDAC being the fourth leading cause of cancer-related deaths in the US. The tumor suppressor miRNA miR-145 downregulates critical pluripotency factors and oncogenes and results in repressed metastatic potential in PDAC. Additionally, the miR-200 family regulates several angiogenic factors which have been linked to metastasis in many solid tumors. We have previously demonstrated that downregulation of DCLK1 can upregulate critical miRNAs in both in vitro and in vivo cancer models and results in downregulation of c-MYC, KRAS, NOTCH1 and EMT-related transcription factors. A recent report has also shown that Dclk1 can distinguish between normal and tumor stem cells in Apc (min/+) mice and that ablation of Dclk1(+) cells resulted in regression of intestinal polyps without affecting homeostasis. Here we demonstrate that the knockdown of DCLK1 using poly(lactide-co-glycolide)-encapsulated-DCLK1-siRNA results in AsPC1 tumor growth arrest. Examination of xenograft tumors revealed, (a) increased miR-145 which results in decreased pluripotency maintenance factors OCT4, SOX2, NANOG, KLF4 as well as KRAS and RREB1; (b) increased let-7a which results in decreased pluripotency factor LIN28B; and (c) increased miR-200 which results in decreased VEGFR1, VEGFR2 and EMT-related transcription factors ZEB1, ZEB2, SNAIL and SLUG. Specificity of DCLK1 post-transcriptional regulation of the downstream targets of miR-145, miR-200 and let-7a was accomplished utilizing a luciferase-based reporter assay. We conclude that DCLK1 plays a significant master regulatory role in pancreatic tumorigenesis through the regulation of multiple tumor suppressor miRNAs and their downstream pro-tumorigenic pathways. This novel concept of targeting DCLK1 alone has several advantages over targeting single pathway or miRNA-based therapies for PDAC.

Inhibition of Metastatic Potential in Breast Carcinoma In Vivo and In Vitro through Targeting VEGFRs and FGFRs

Angiogenesis and lymphangiogenesis are considered to play key roles in tumor metastasis. Targeting receptor tyrosine kinases essentially involved in the angiogenesis and lymphangiogenesis would theoretically prevent cancer metastasis. However, the optimal multikinase inhibitor for metastasis suppression has yet to be developed. In this study, we evaluated the effect of NSTPBP 0100194-A (194-A), a multikinase inhibitor of vascular endothelial growth factor receptors (VEGFRs)/fibroblast growth factor receptors (FGFRs), on lymphangiogenesis and angiogenesis in a mammary fat pad xenograft model of the highly invasive breast cancer cell line 4T1-Luc⁺. We investigated the biologic effect of 194-A on various invasive breast cancer cell lines as well as endothelial and lymphatic endothelial cells. Intriguingly, we found that 194-A drastically reduced the formation of lung, liver, and lymph node metastasis of 4T1-Luc⁺ and decreased primary tumor growth. This was associated with significant reductions in intratumoral lymphatic vessel length (LVL) and microvessel density (MVD). 194-A blocked VEGFRs mediated signaling on both endothelial and lymphatic endothelial cells. Moreover, 194-A significantly inhibited the invasive capacity induced by VEGF-C or FGF-2 in vitro in both 4T1 and MDA-MB231 cells. In conclusion, these experimental results demonstrate that simultaneous inhibition of VEGFRs/FGFRs kinases may be a promising strategy to prevent breast cancer metastasis.

Anti-pancreatic cancer deliverables from sea: first-hand evidence on the efficacy, molecular targets and mode of action for multifarious polyphenols from five different brown-algae

Pancreatic cancer (PC) remains the fourth leading cause of cancer death with an unacceptable survival that has remained relatively unchanged over the past 25 years. The presence of occult or clinical metastases at the time of diagnosis together with the lack of effective chemotherapies pose a dire need for designing new and targeted therapeutic deliverables that favors the clinical outcome. Herein, we investigated the anti-tumorigenic potential of polyphenols from five different brown-algae in human PC cells (MiaPaCa-2, Panc-1, BXPC-3 and Panc-3.27). Total anti-oxidant capacity (TAC) analysis on stepwise polyphenol separations with increasing polarity (Hexane-DCM-EA-methanol) identified high levels of TAC in DCM and EA extractions across all seaweeds assessed. All DCM and EA separated polyphenols induced a dose-dependent and sustained (time-independent) inhibition of cell proliferation and viability. Further, these polyphenols profoundly enhanced DNA damage (acridine orange/Ethidium bromide staining and DNA fragmentation) in all the cell lines investigated. More importantly, luciferase reporter assay revealed a significant inhibition of NFκB transcription in cells treated with polyphenols. Interestingly, QPCR analysis identified a differential yet definite regulation of pro-tumorigenic EGFR, VEGFA, AKT, hTERT, kRas, Bcl2, FGFα and PDGFα transcription in cells treated with DCM and EA polyphenols. Immunoblotting validates the inhibitory potential of seaweed polyphenols in EGFR phosphorylation, kRas, AurKβ and Stat3. Together, these data suggest that intermediate polarity based fractions of seaweed polyphenols may significantly potentiate tumor cell killing and may serve as potential drug deliverable for PC cure. More Studies dissecting out the active constituents in potent fractions, mechanisms of action and synergism, if any, are warranted and are currently in process.

Comparison of drug and cell-based delivery: engineered adult mesenchymal stem cells expressing soluble tumor necrosis factor receptor II prevent arthritis in mouse and rat animal models

Rheumatoid arthritis (RA) is a systemic autoimmune disease with unknown etiology where tumor necrosis factor-α (TNFα) plays a critical role. Etanercept, a recombinant fusion protein of human soluble tumor necrosis factor receptor II (hsTNFR) linked to the Fc portion of human IgG1, is used to treat RA based on the rationale that sTNFR binds TNFα and blocks TNFα-mediated inflammation. We compared hsTNFR protein delivery from genetically engineered human mesenchymal stem cells (hMSCs) with etanercept. Blocking TNFα-dependent intercellular adhesion molecule-1 expression on transduced hMSCs and inhibition of nitric oxide production from TNFα-treated bovine chondrocytes by conditioned culture media from transduced hMSCs demonstrated the functionality of the hsTNFR construction. Implanted hsTNFR-transduced mesenchymal stem cells (MSCs) reduced mouse serum circulating TNFα generated from either implanted TNFα-expressing cells or lipopolysaccharide induction more effectively than etanercept (TNFα, 100%; interleukin [IL]-1α, 90%; and IL-6, 60% within 6 hours), suggesting faster clearance of the soluble tumor necrosis factor receptor (sTNFR)-TNFα complex from the animals. In vivo efficacy of sTNFR-transduced MSCs was illustrated in two (immune-deficient and immune-competent) arthritic rodent models. In the antibody-induced arthritis BalbC/SCID mouse model, intramuscular injection of hsTNFR-transduced hMSCs reduced joint inflammation by 90% compared with untransduced hMSCs; in the collagen-induced arthritis Fischer rat model, both sTNFR-transduced rat MSCs and etanercept inhibited joint inflammation by 30%. In vitro chondrogenesis assays showed the ability of TNFα and IL1α, but not interferon γ, to inhibit hMSC differentiation to chondrocytes, illustrating an additional negative role for inflammatory cytokines in joint repair. The data support the utility of hMSCs as therapeutic gene delivery vehicles and their potential to be used in alleviating inflammation within the arthritic joint.

Blocking Fibroblast Growth Factor receptor signaling inhibits tumor growth, lymphangiogenesis, and metastasis

Fibroblast Growth Factor receptor (FGFR) activity plays crucial roles in tumor growth and patient survival. However, FGF (Fibroblast Growth Factor) signaling as a target for cancer therapy has been under-investigated compared to other receptor tyrosine kinases. Here, we studied the effect of FGFR signaling inhibition on tumor growth, metastasis and lymphangiogenesis by expressing a dominant negative FGFR (FGFR-2DN) in an orthotopic mouse mammary 66c14 carcinoma model. We show that FGFR-2DN-expressing 66c14 cells proliferate in vitro slower than controls. 66c14 tumor outgrowth and lung metastatic foci are reduced in mice implanted with FGFR-2DN-expressing cells, which also exhibited better overall survival. We found 66c14 cells in the lumen of tumor lymphatic vessels and in lymph nodes. FGFR-2DN-expressing tumors exhibited a decrease in VEGFR-3 (Vascular Endothelial Growth Factor Receptor-3) or podoplanin-positive lymphatic vessels, an increase in isolated intratumoral lymphatic endothelial cells and a reduction in VEGF-C (Vascular Endothelial Growth Factor-C) mRNA expression. FGFs may act in an autocrine manner as the inhibition of FGFR signaling in tumor cells suppresses VEGF-C expression in a COX-2 (cyclooxygenase-2) or HIF1-α (hypoxia-inducible factor-1 α) independent manner. FGFs may also act in a paracrine manner on tumor lymphatics by inducing expression of pro-lymphangiogenic molecules such as VEGFR-3, integrin α9, prox1 and netrin-1. Finally, in vitro lymphangiogenesis is impeded in the presence of FGFR-2DN 66c14 cells. These data confirm that both FGF and VEGF signaling are necessary for the maintenance of vascular morphogenesis and provide evidence that targeting FGFR signaling may be an interesting approach to inhibit tumor lymphangiogenesis and metastatic spread.

Evaluation of poly-mechanistic antiangiogenic combinations to enhance cytotoxic therapy response in pancreatic cancer

Gemcitabine (Gem) has limited clinical benefits in pancreatic ductal adenocarcinoma (PDAC). The present study investigated combinations of gemcitabine with antiangiogenic agents of various mechanisms for PDAC, including bevacizumab (Bev), sunitinib (Su) and EMAP II. Cell proliferation and protein expression were analyzed by WST-1 assay and Western blotting. In vivo experiments were performed via murine xenografts. Inhibition of in vitro proliferation of AsPC-1 PDAC cells by gemcitabine (10 µM), bevacizumab (1 mg/ml), sunitinib (10 µM) and EMAP (10 µM) was 35, 22, 81 and 6 percent; combination of gemcitabine with bevacizumab, sunitinib or EMAP had no additive effects. In endothelial HUVECs, gemcitabine, bevacizumab, sunitinib and EMAP caused 70, 41, 86 and 67 percent inhibition, while combination of gemcitabine with bevacizumab, sunitinib or EMAP had additive effects. In WI-38 fibroblasts, gemcitabine, bevacizumab, sunitinib and EMAP caused 79, 58, 80 and 29 percent inhibition, with additive effects in combination as well. Net in vivo tumor growth inhibition in gemcitabine, bevacizumab, sunitinib and EMAP monotherapy was 43, 38, 94 and 46 percent; dual combinations of Gem+Bev, Gem+Su and Gem+EMAP led to 69, 99 and 64 percent inhibition. Combinations of more than one antiangiogenic agent with gemcitabine were generally more effective but not superior to Gem+Su. Intratumoral proliferation, apoptosis and microvessel density findings correlated with tumor growth inhibition data. Median animal survival was increased by gemcitabine (26 days) but not by bevacizumab, sunitinib or EMAP monotherapy compared to controls (19 days). Gemcitabine combinations with bevacizumab, sunitinib or EMAP improved survival to similar extent (36 or 37 days). Combinations of gemcitabine with Bev+EMAP (43 days) or with Bev+Su+EMAP (46 days) led to the maximum survival benefit observed. Combination of antiangiogenic agents improves gemcitabine response, with sunitinib inducing the strongest effect. These findings demonstrate advantages of combining multi-targeting agents with standard gemcitabine therapy for PDAC.

Fibroblast growth factor signaling in non-small-cell lung cancer

Despite recent progress in the treatment on non-small cell lung cancer (NSCLC), outcomes remain suboptimal. Treatment advances that target the epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) signaling pathways highlight the need to understand the multiple convergent growth factor signaling pathways involved in the pathogenesis of NSCLC. Signaling through fibroblast growth factors (FGF), long recognized for its pro-angiogenic activity, has recently emerged as a contributing factor in the pathogenesis and progression of NSCLC through an autocrine signaling loop. In addition, this pathway may function as a mechanism of resistance to anti-EGFR and anti-VEGF treatment. Clinical experience with FGF receptor (FGFR) inhibitors is mounting, and more specific inhibitors of this signaling pathway are in development. This review describes the structure of the FGF signaling pathway, delineates its dual roles in angiogenesis and proliferation in NSCLC, evaluates FGF ligand and receptor expression as prognostic biomarkers in NSCLC, and discusses the development of FGF pathway inhibitors for the treatment of lung malignancies.

A novel, selective inhibitor of fibroblast growth factor receptors that shows a potent broad spectrum of antitumor activity in several tumor xenograft models

The fibroblast growth factor receptors (FGFR) are tyrosine kinases that are present in many types of endothelial and tumor cells and play an important role in tumor cell growth, survival, and migration as well as in maintaining tumor angiogenesis. Overexpression of FGFRs or aberrant regulation of their activities has been implicated in many forms of human malignancies. Therefore, targeting FGFRs represents an attractive strategy for development of cancer treatment options by simultaneously inhibiting tumor cell growth, survival, and migration as well as tumor angiogenesis. Here, we describe a potent, selective, small-molecule FGFR inhibitor, (R)-(E)-2-(4-(2-(5-(1-(3,5-Dichloropyridin-4-yl)ethoxy)-1H-indazol-3yl)vinyl)-1H-pyrazol-1-yl)ethanol, designated as LY2874455. This molecule is active against all 4 FGFRs, with a similar potency in biochemical assays. It exhibits a potent activity against FGF/FGFR-mediated signaling in several cancer cell lines and shows an excellent broad spectrum of antitumor activity in several tumor xenograft models representing the major FGF/FGFR relevant tumor histologies including lung, gastric, and bladder cancers and multiple myeloma, and with a well-defined pharmacokinetic/pharmacodynamic relationship. LY2874455 also exhibits a 6- to 9-fold in vitro and in vivo selectivity on inhibition of FGF- over VEGF-mediated target signaling in mice. Furthermore, LY2874455 did not show VEGF receptor 2-mediated toxicities such as hypertension at efficacious doses. Currently, this molecule is being evaluated for its potential use in the clinic.

Antitumor activity of a recombinant soluble ectodomain of mutant human fibroblast growth factor receptor-2 IIIc

The fibroblast growth factor (FGF) signaling pathway is a recognized target of cancer therapy. We have developed a strong inhibitor (S252W mutant soluble ectodomain of FGF recptor-2 IIIc, msFGFR2) that binds FGFs and blocks the activation of FGFRs. Thermodynamic binding studies indicated that msFGFR2 bound FGF-2 16.9 times as strongly as wild-type soluble FGFR2IIIc ectodomain (wsFGFR2). It successfully suppressed the growth, angiogenesis, and metastasis of two tumor cell lines in vitro and in vivo, and it potently inhibited cancer cell proliferation but not normal cell proliferation. Therefore, msFGFR2 is a useful probe for FGF-dependent signaling pathways and a potential broad-spectrum antitumor agent.

Soluble FGFR4 extracellular domain inhibits FGF19-induced activation of FGFR4 signaling and prevents nonalcoholic fatty liver disease

Fibroblast growth factor receptor 4 (FGFR4) is a transmembrane tyrosine kinase receptor that plays a crucial role in the regulation of hepatic bile acid and lipid metabolism. FGFR4 underlies high-fat diet-induced hepatic steatosis, suggesting that inhibition of FGFR4 activation may be an effective way to prevent or treat nonalcoholic fatty liver disease (NAFLD). To determine whether neutralization of FGFR4 ligands by soluble FGFR4 extracellular domain (FGFR4-ECD) can inhibit the activation of FGFR4, we constructed FGFR4-ECD expression vector and showed that FGFR4-ECD was effectively expressed in cells and secreted into culture medium. FGFR4-ECD inhibited FGF19-induced activation of FGFR4 signaling and reduced steatosis of HepG2 induced by palmitic acid in vitro. Furthermore, in a tetracycline-induced fatty liver model, expression of FGFR4-ECD in mouse liver reduced the accumulation of hepatic lipids and partially restored the expression of peroxisome proliferator-activated receptor α (PPARα), which promotes the mitochondrial fatty acid beta-oxidation but is repressed by tetracycline. Taken together, these results demonstrate that FGFR4-ECD can block FGFR4 signaling and prevent hepatic steatosis, highlighting the potential value of inhibition of FGFR4 signaling as a method for therapeutic intervention against NAFLD.

CD39/ENTPD1 expression by CD4+Foxp3+ regulatory T cells promotes hepatic metastatic tumor growth in mice

BACKGROUND & AIMS

Adenosine mediates immune suppression and is generated by the ectonucleotidases CD39 (ENTPD1) and CD73 that are expressed on vascular endothelial cells and regulatory T cells (Tregs). Although tumor-infiltrating immune cells include Foxp3(+) Tregs, it is not clear whether local adenosine generation by Tregs promotes tumor growth in a CD39-dependent manner. In this study, we have examined the effect of CD39 expression by Tregs on effector immune cell responses to hepatic metastases in vivo.

METHODS

A model of hepatic metastatic cancer was developed with portal vein infusion of luciferase-expressing melanoma B16/F10 cells and MCA38 colon cancer cells in wild-type (wt) and mutant mice null for Cd39. Chimeric mice were generated by bone marrow transplantation (BMT) using Cd39 null or wt C57BL6 donors and irradiated recipient mice.

RESULTS

We demonstrate that hepatic growth of melanoma metastatic tumors was strongly inhibited in mice with Cd39 null vasculature or in wt mice with circulating Cd39 null bone marrow-derived cells. We show functional CD39 expression on CD4(+)Foxp3(+) Tregs suppressed antitumor immunity mediated by natural killer (NK) cells in vitro and in vivo. Finally, inhibition of CD39 activity by polyoxometalate-1, a pharmacologic inhibitor of nucleoside triphosphate diphosphohydrolase activity, significantly inhibited tumor growth (P < .001).

CONCLUSIONS

CD39 expression on Tregs inhibits NK activity and is permissive for metastatic growth. Pharmacologic or targeted inhibition of CD39 enzymatic activity may find utility as an adjunct therapy for secondary hepatic malignancies.

The fibroblast growth factor receptor signaling pathway as a mediator of intrinsic resistance to EGFR-specific tyrosine kinase inhibitors in non-small cell lung cancer

The EGFR has been targeted through the development of selective tyrosine kinase inhibitors (TKIs) that have proven effective in a subset of non-small cell lung cancer (NSCLC) patients, many bearing gain-of-function EGFR mutations or egfr gene amplification. However, the majority ( approximately 80-90%) of NSCLC patients do not respond to EGFR-specific TKIs and a high rate of acquired resistance to these therapeutics is observed in those that do respond. Thus, EGFR-specific TKIs will not, as single agents, make a high impact on overall lung cancer survival. A number of studies support the activities of other receptor tyrosine kinase pathways including cMet, IGF-1R and FGFRs as mechanisms for both intrinsic and acquired resistance to EGFR TKIs. While the role of cMet and IGF-1R signaling systems as mechanisms of resistance to EGFR TKIs has been widely reviewed in recent years, the potential role of FGFR-dependent signaling as a mechanism for EGFR TKI resistance has more recently emerged and will be highlighted herein. Due to the high degree of homology of FGFRs with VEGFRs and PDGFRs, FGFR-active TKIs already exist via development of VEGFR-targeted TKIs as angiogenesis inhibitors. Thus, these agents could be rapidly advanced into clinical investigations as FGFR inhibitors, either alone or in combination with TKIs selective for EGFR, cMet or IGF-1R as a means to expand the spectrum of NSCLC patients that can be effectively targeted with TKI-directed therapies.

Paths of FGFR-driven tumorigenesis

Fibroblast growth factor receptors (FGFRs) comprise a subfamily of receptor tyrosine kinases (RTKs) that are master regulators of a broad spectrum of cellular and developmental processes, including apoptosis, proliferation, migration and angiogenesis. Due to their broad impact, FGFRs and other RTKs are highly regulated and normally only basally active. Deregulation of FGFR signaling by activating mutations or ligand/receptor overexpression could allow these receptors to become constitutively active, leading to cancer development, including both hematopoietic and solid tumors, such as breast, bladder and prostate carcinomas. In this review, we focus on potential modes of FGFR-mediated tumorigenesis, in particular, the role of FGFR1 during prostate cancer progression.

A phase II study evaluating bevacizumab in combination with fixed-dose rate gemcitabine and low-dose cisplatin for metastatic pancreatic cancer: is an anti-VEGF strategy still applicable?

BACKGROUND

The role of bevacizumab, a recombinant humanized monoclonal antibody directed against vascular endothelial growth factor, in the treatment of pancreatic cancer remains unclear. The objectives of this study were to determine safety and efficacy in chemotherapy-naive patients with metastatic pancreatic cancer receiving bevacizumab in combination with fixed-dose rate (FDR) gemcitabine and low-dose cisplatin.

METHODS

Eligible patients received gemcitabine 1,000 mg/m2 at FDR infusion (10 mg/m(2) per minute), cisplatin 20 mg/m(2), and bevacizumab 10 mg/kg, on days 1 and 15 of a 28-day cycle. Patients were monitored by computed tomography scans every two cycles and monthly serum CA19-9 measurements.

RESULTS

Of 52 patients eligible for analysis, ten (19.2%) had an unconfirmed response and 30 (57.7%) had stable disease. Of 35 patients with elevated baseline CA19-9 levels, 20 (57.1%) had > or = 50% biomarker decline during treatment. Median time to tumor progression was 6.6 months and median survival was 8.2 months (estimated 1-year survival, 36%). Grade 3/4 toxicities possibly related to bevacizumab included thromboembolic events (15.1%), hypertension (13.2%), gastrointestinal bleeding (9.4%), cardiac events (7.5%), and bowel perforation (5.7%). Plasma vascular endothelial growth factor and basic fibroblast growth factor levels and circulating tumor cell concentration did not correlate with overall survival, either at baseline or after 2 months of therapy.

CONCLUSIONS

This bevacizumab-containing study regimen is modestly effective in patients with metastatic pancreatic cancer, although occasional serious complications may occur. Given the negative results of CALGB 80303, future efforts should be focused on identifying those specific patients who are most likely to benefit from bevacizumab-based therapy.

Oligosaccharides as anti-angiogenic agents

BACKGROUND

Several studies of drugs that inhibit tumour angiogenesis have shown improvements in the survival of cancer patients, thus validating angiogenesis as a clinically relevant target. Both intracellular and extracellular approaches have shown promising results in clinical situations.

OBJECTIVES

To compare and contrast oligosaccharide therapies and other anti-angiogenic compounds for their benefits and toxicity.

METHODS

Analysis of the relevant literature including presentations at recent conferences.

RESULTS

Receptor tyrosine kinase inhibitors are orally available but have a broad spectrum of activity which is associated with toxicity. Antibodies are associated with different toxicities, however, they are administered parenterally. Oligosaccharides that act as competitive inhibitors of heparan sulfate (HS) are in the early and late phases of clinical development. The advantage of oligosaccharides should be that they can be designed to target several angiogenic molecules, that they are relatively safe and that they can be administered subcutaneously at home. The key questions concerning their development focus on whether compounds with sufficient affinity and relative specificity can be generated, whether they are active at doses that do not perturb the coagulation cascade to a clinically dangerous level, whether the synthetic routes are scalable and, whether the current Phase III trials will yield positive results.

CONCLUSIONS

Saccharides represent a novel and exciting therapeutic approach that targets a spectrum of angiogenic molecules that cannot be inhibited through established drug development programmes.

Fibrinogen synthesized by cancer cells augments the proliferative effect of fibroblast growth factor-2 (FGF-2)

BACKGROUND

Fibroblast growth factor (FGF)-2 is a critical growth factor in normal and malignant cell proliferation and tumor-associated angiogenesis. Fibrinogen and fibrin bind to FGF-2 and modulate FGF-2 functions. Furthermore, we have shown that extrahepatic epithelial cells are capable of endogenous production of fibrinogen.

OBJECTIVE

Herein we examined the role of fibrinogen and FGF-2 interactions on prostate and lung adenocarcinoma cell growth in vitro.

METHODS

Cell proliferation was measured by (3)H-thymidine uptake and the specificity of FGF-2-fibrinogen interactions was measured using wild-type and mutant FGF-2s, fibrinogen gamma-chain (FGG) RNAi and co-immunoprecipitation. Metabolic labeling, immunopurification and fluorography demonstrated de novo fibrinogen production.

RESULTS

FGF-2 stimulated DU-145 cell proliferation, whereas neither FGF-2 nor fibrinogen affected the growth of PC-3 or A549 cells. Fibrinogen augmented the proliferative effect of FGF-2 on DU-145 cells. The role of fibrinogen in FGF-2-enhanced DNA synthesis was confirmed using an FGF-2 mutant that exhibits no binding affinity for fibrinogen. FGG transcripts were present in PC-3, A549 and DU-145 cells, but only PC-3 and A549 cells produced detectable levels of intact protein. RNAi-mediated knockdown of FGG expression resulted in decreased production of fibrinogen protein and inhibited (3)H-thymidine uptake in A549 and PC-3 cells by 60%, which was restored by exogenously added fibrinogen. FGF-2 and fibrinogen secreted by the cells were present in the medium as a soluble complex, as determined by coimmunoprecipitation studies.

CONCLUSIONS

These data indicate that endogenously synthesized fibrinogen promotes the growth of lung and prostate cancer cells through interaction with FGF-2.

Soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) is decreased in lung cancer patients showing progression: a pilot study

Tumor growth and metastasis depend on angiogenesis, and the vascular endothelial growth factor (VEGF) is known to be one of the most important angiogenic factors although the knowledge about its receptors is limited. We, therefore, investigated the treatment-related changes both in the level of the soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) in the serum by ELISA and the expression of VEGFR-1 in cancer tissues by immunohistochemistry. The serum levels were studied in 38 lung cancer patients, and 55 control subjects (21 benign disease and 34 healthy subjects) before the chemotherapy. The treatment-related changes in serum sVEGFR-1 were evaluated in 15 patients 24 and 48 hours after treatment. In addition to serum analysis, the tissue expressions were evaluated in 32 patients before treatment. The treatment-related changes in tissue VEGFR-1 expressions were evaluated in only 12 patients 24 hours after treatment. We observed no significant difference in terms of serum sVEGFR-1 levels between malignant and nonmalignant groups (p > 0.05). There were no significant differences in the levels of sVEGFR-1 before and after treatment (p > 0.05). However, there was a significant difference between sVEGFR-1 levels in the groups (regressive, stable, progressive) classified according to the response to therapy (p = 0.043). A significant difference also was present between the expression levels of tissue VEGFR-1 in the same groups (p = 0.037). As a conclusion, we suggest that prechemotherapy sVEGFR-1 can be helpful for prediction of long-term response to therapy, but it should be studied in larger groups to elucidate its benefit in clinics.

Future strategies for targeted therapies and tailored patient management in pancreatic cancer

Pancreatic cancer represents the fourth leading cause of cancer-related mortality in the United States. The vast majority of patients are diagnosed at advanced stages of the disease, at which time gemcitabine-based chemotherapy is typically offered as the standard of care. However, as investigators have arrived at a greater understanding of pancreatic tumor biology, newer therapeutic agents that "target" specific pathways or molecules governing the growth, spread, and maintenance of tumor cells have gained considerable interest. Erlotinib, an orally bioavailable small molecule inhibitor of the epidermal growth factor receptor, is the first of these targeted compounds to be approved for use in combination with gemcitabine for patients with advanced pancreatic cancer. Other targeted agents, including monoclonal antibodies and small molecule inhibitors aimed at a variety of targets, also have been extensively evaluated, with limited success to date. A newer strategy worth pursuing involves tailoring an individual patient's therapy according to the molecular characteristics of both host and tumor, as has shown promise in other solid tumor types.

Polyphosphate blocks tumour metastasis via anti-angiogenic activity

PolyP (inorganic polyphosphate) is a linear polymer of many tens or hundreds of orthophosphate residues found in a wide range of organisms, including bacteria, fungi, insects, plants and vertebrates. Despite its wide distribution in mammalian tissues and plasma, the biological functions of polyP on tumour metastasis and angiogenesis have not been previously examined. In the present study, we have shown that polyP effectively blocked in vivo pulmonary metastasis of B16BL6 cells by suppression of neovascularization, whereas it did not affect proliferation or adhesion to extracellular matrix proteins. PolyP not only inhibited bFGF (basic fibroblast growth factor)-induced proliferation and ERK (extracellular-signal-regulated kinase)/p38 MAPK (mitogen-activated protein kinase) activation of human endothelial cells, but also blocked the binding of bFGF to its cognate cell-surface receptor. Furthermore, polyP inhibited bFGF-induced in vitro and in vivo angiogenesis, suggesting that polyP possesses an anti-angiogenic activity. Since neovascularization is essential for tumour metastasis, our present findings clearly indicate that polyP has an in vivo anti-metastatic activity via its anti-angiogenic activity. Taken together with the fact that angiogenesis occurs under various normal and pathological conditions, our observations suggest that endogenous polyP may play a critical role during embryonic development, wound healing and inflammation, as well as in the progress of pathological diseases such as rheumatoid arthritis and cancer.

Identification of a fibroblast growth factor receptor 1 splice variant that inhibits pancreatic cancer cell growth

Fibroblast growth factor receptors (FGFR) play important roles in many biological processes. Nothing is presently known about possible roles of the human FGFR1-IIIb mRNA splice variant. In this study, we characterized for the first time the effects of FGFR1-IIIb expression on the transformed phenotype of human pancreatic cancer cells. The full-length FGFR1-IIIb cDNA was generated and stably expressed in PANC-1 and MIA PaCa-2 pancreatic cancer and TAKA-1 pancreatic ductal cells. FGFR1-IIIb-expressing cells synthesized a glycosylated 110-kDa protein enhancing tyrosine phosphorylation of FGFR substrate-2 on FGF-1 stimulation. The basal anchorage-dependent and anchorage-independent cell growth was significantly inhibited. These effects were associated with a marked reduction of p44/42 mitogen-activated protein kinase (MAPK) phosphorylation in combination with enhanced activity of p38 MAPK and c-Jun NH(2)-terminal kinase. FGFR1-IIIb expression inhibited single-cell movement and in vitro invasion as determined by time-lapse microscopy and Boyden chamber assay as well as in vivo tumor formation and growth in nude mice. Microscopic analysis of the xenograft tumors revealed a reduced Ki-67 labeling and a lower amount of tumor necrosis in FGFR1-IIIb-expressing tumors. Our results show that FGFR1-IIIb is a functional FGFR that inhibits the transformed phenotype of human pancreatic cancer cells.

Gain of chromosome 8q: a potential prognostic marker in resectable adenocarcinoma of the pancreas?

BACKGROUND

The objective of this study was to identify genomic alterations in resectable pancreatic cancer (PCA). Chromosomal imbalances were correlated with histopathological and clinical data to verify their prognostic significance.

METHODS

Specimens of 33 PCA were investigated by comparative genomic hybridization. Microdissection was used for separation of PCA from the normal cells before isolation of DNA; nick-end labeling and hybridization were performed according to standard protocols. Aberrations were correlated with staging and grading using log-rank test and Cox regression. Survival rates were plotted using the Kaplan-Meier method.

RESULTS

Twenty-eight (85%) PCA showed aberrations. Gains of chromosomal material were most frequently identified on 8q (42%), 13q (30%), 18p (21%), and 3q (18%). Genetic losses were frequently detected on 1p (45%), 22 (42%), 19 (36%), 17p (27%), 18q and 8p (15% each), and 3p (12%). Losses of 8p (n = 5) and 3p (n = 4) were only detected in stages III and IV (P < 0.05). Median survival time of all patients was 13 months. Median survival time of patients with aberration of 8q (n = 14) was 8.5 months compared to 16 months in patients without gain of 8q (n = 19; P = 0.029).

CONCLUSIONS

The chromosomal regions containing genetic alterations represent potential loci for new target genes in PCA. The significant correlation of gain of chromosome 8q with short survival time suggests that 8q may be a new marker to assess prognosis and malignant potential of resected PCA in the individual patient, thereby helping to identify patients at risk for recurrence that might profit from adjuvant therapy.

Tumor hypoxia and targeted gene therapy

Hypoxia is an integral characteristic of the tumor microenvironment, primarily due to the microvascular defects that accompany the accelerated neoplastic growth. The presence of tumor hypoxic areas correlates with negative outcome after radiotherapy, chemotherapy, and surgery, as hypoxia not only provides an environment directly facilitating chemo- and radio-resistance, but also encourages the evolution of phenotypic changes inducing permanent resistance to treatment and metastatic spread. Therefore, successful treatment of hypoxic cells has the potential to not only improve local control but also impact overall patient survival. Specific and selective targeting of hypoxic tumor areas can be achieved at all three steps of a gene therapy treatment: delivery of the therapeutic gene to the tumor, regulation of gene expression, and therapeutic efficacy. In this review the latest developments and innovations in hypoxia-targeted gene therapy are discussed. In particular, approaches such as hypoxia-conditionally replicating viruses, cellular vehicles, and gene therapy means to disrupt the hypoxia-inducible factor (HIF) signaling are outlined.

Inhibition of c-Met and prevention of spontaneous metastatic spreading by the 2-indolinone RPI-1

Hepatocyte growth factor (HGF) and its tyrosine kinase receptor Met play a pivotal role in the tumor metastatic phenotype and represent attractive therapeutic targets. We investigated the biochemical and biological effects of the tyrosine kinase inhibitor RPI-1 on the human lung cancer cell lines H460 and N592, which express constitutively active Met. RPI-1-treated cells showed down-regulation of Met activation and expression, inhibition of HGF/Met-dependent downstream signaling involving AKT, signal transducers and activators of transcription 3 and paxillin, as well as a reduced expression of the proangiogenic factors vascular endothelial growth factor and basic fibroblast growth factor. Cell growth in soft agar of H460 cells was strongly reduced in the presence of the drug. Furthermore, RPI-1 inhibited both spontaneous and HGF-induced motility/invasiveness of both H460 and human endothelial cells. Targeting of Met signaling by alternative methods (Met small interfering RNA and anti-phosphorylated Met antibody intracellular transfer) produced comparable biochemical and biological effects. Using the spontaneously metastasizing lung carcinoma xenograft H460, daily oral treatment with well-tolerated doses of RPI-1 produced a significant reduction of spontaneous lung metastases (-75%; P < 0.001, compared with control mice). In addition, a significant inhibition of angiogenesis in primary s.c. tumors of treated mice was observed, possibly contributing to limit the development of metastases. The results provide preclinical evidence in support of Met targeting pharmacologic approach as a new option for the control of tumor metastatic dissemination.

Anti-angiogenic drugs: from bench to clinical trials

Angiogenesis, the generation of new capillaries through a process of pre-existing microvessel sprouting, is under stringent control and normally occurs only during embryonic and post-embryonic development, reproductive cycle, and wound repair. However, in many pathological conditions (solid tumor progression, metastasis, diabetic retinopathy, hemangioma, arthritis, psoriasis and atherosclerosis among others), the disease appears to be associated with persistent upregulated angiogenesis. The development of specific anti-angiogenic agents arises as an attractive therapeutic approach for the treatment of cancer and other angiogenesis-dependent diseases. The formation of new blood vessels is a complex multi-step process. Endothelial cells resting in the parent vessels are activated by an angiogenic signal and stimulated to synthesize and release degradative enzymes allowing endothelial cells to migrate, proliferate and finally differentiate to give rise to capillary tubules. Any of these steps may be a potential target for pharmacological intervention. In spite of the disappointing results obtained initially in clinical trials with anti-angiogenic drugs, recent reports with positive results in phases II and III trials encourage expectations in their therapeutic potential. This review discusses the current approaches for the discovery of new compounds that inhibit angiogenesis, with emphasis on the clinical developmental status of anti-angiogenic drugs.

Decreased Growth Rate of Lung Metastatic Lesions after Splenectomy in Mice

BACKGROUND

The effect of splenectomy on hematogenous metastases of malignant tumors remains controversial. The aim of this study was to clarify the effect of splenectomy on hematogenous metastases in an animal model.

METHODS

Colon 26 cancer cells were inoculated into the lateral tail vein of 90 mice. The mice were then assigned to a splenectomy group or a control group. Lung weight, number of lung metastases, size of metastatic nodules, and serum vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) levels after the surgical procedure were measured and compared between the two groups.

RESULTS

The lung nodules were significantly smaller in the splenectomy group than in the control group. In both groups, the serum VEGF levels increased on day 1 and then decreased. The serum VEGF levels on day 5 were significantly lower in the splenectomy group than in the control group. The serum bFGF levels were significantly lower in the splenectomy group than in the control group on days 1 and 5. Immunohistochemical study showed that bFGF was produced by reticuloendothelial cells of the spleen.

CONCLUSION

The growth rate of hematogenous metastatic lesions appears to decrease after splenectomy and may be associated with decreases in serum levels of VEGF and bFGF induced by splenectomy.

Angiogenesis in Atherogenesis

Atherogenesis is the pathobiological process, which underlies atherosclerotic cardiovascular disease and evolves in the 3 stages of initiation, progression, and complication to clinical significance. Of note, this process is associated with neovascularization, and it was not until recently that the implications of angiogenesis in atherogenesis were delineated. This article gives an updated overview on this topic and briefly reflects on the similarities with neovessel formation in carcinogenesis.

Extracellular angiogenic growth factor interactions: an angiogenesis interactome survey

Angiogenesis plays a key role in various physiological and pathological processes, including inflammation and tumor growth. Numerous angiogenic growth factors (AGFs) have been identified. Usually, the angiogenic process is assumed to represent the outcome of a straightforward interaction of AGFs with specific signalling receptors of the endothelial cell (EC) surface. Actually, the mechanisms by which AGFs induce neovascularization are much more complex. Indeed, angiogenesis is the result of the simultaneous actions of various AGFs and angiogenesis modulators; multiple EC surface receptors with different structure and biological properties are engaged by AGFs to exert a full angiogenic response; AGFs bind a variety of free and immobilized proteins, polysaccharides, and complex lipids of the extracellular milieu that affect AGF integrity, stability, and bioavailability; some of the AGF-binding molecules interact also with AGF receptors. In this review the authors summarize literature data and discuss the current knowledge about the extracellular molecules able to interact with AGFs, thus representing possible key regulators of the angiogenesis process and targets/templates for the development of novel antiangiogenic drugs. This work represents an attempt to highlight common theme in the AGF interactome that occurs at the extracellular level during neovascularization.

Basic fibroblast growth factor and fibroblastic growth factor receptor-1 may contribute to head and neck paraganglioma development by an autocrine or paracrine mechanism

Paragangliomas are hypervascular tumors arising from neural crest-derived paraganglia that are associated with the autonomic nerve system. Mutations in genes coding for subunits of mitochondrial complex II are associated with hereditary paragangliomas, and it has been suggested that these mutations result in a pseudohypoxic signal triggering tumorigenesis. Fibroblastic growth factors are hypoxia-inducible angiogenic stimuli that are involved in the angiogenesis and tumorigenesis of several neoplasms. It has been demonstrated that basic fibroblastic growth factor (bFGF) is a survival factor for cultured chief cells of the carotid body, capable of inducing proliferation. To examine the role of this growth factor in paragangliomas, we studied the immunohistochemical expression of bFGF and its high affinity receptor fibroblastic growth factor receptor 1 (FGFR1) in 7 normal carotid bodies and in 33 head and neck paragangliomas, including 2 malignant cases and their metastases. Immunohistochemical expression of bFGF and FGFR1 in tumors was confirmed by real-time polymerase chain reaction. FGFR1 was moderately present in carotid bodies, and there was strong and significantly enhanced cytoplasmatic staining of FGFR1 in all paragangliomas. Chief cells in carotid bodies and tumors showed strong cytoplasmatic staining for bFGF. The results indicate that FGFR1 and bFGF may contribute to the development of head and neck paragangliomas.

Genetics and biology of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer death in the United States with a median survival of <6 mo and a dismal 5-yr survival rate of 3%-5%. The cancer's lethal nature stems from its propensity to rapidly disseminate to the lymphatic system and distant organs. This aggressive biology and resistance to conventional and targeted therapeutic agents leads to a typical clinical presentation of incurable disease at the time of diagnosis. The well-defined serial histopathologic picture and accompanying molecular profiles of PDAC and its precursor lesions have provided the framework for emerging basic and translational research. Recent advances include insights into the cancer's cellular origins, high-resolution genomic profiles pointing to potential new therapeutic targets, and refined mouse models reflecting both the genetics and histopathologic evolution of human PDAC. This confluence of developments offers the opportunity for accelerated discovery and the future promise of improved treatment.

Herbal melanin modulates tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6) and vascular endothelial growth factor (VEGF) production

Recent studies have indicated that cytokines can enhance immunogenicity and promote tumor regression. However, the means for modulating cytokine production are not yet fully investigated. In this study we report the effects of a herbal melanin, extracted from Nigella sativa L., on the production of three cytokines [tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6) and vascular endothelial growth factor (VEGF)], by human monocytes, total peripheral blood mononuclear cells (PBMC) and THP-1 cell line. Cells were treated with variable concentrations of melanin and the expression of TNF-alpha, IL-6 and VEGF mRNA in cell lysates and secretion of proteins in the supernatants were detected by RT-PCR and ELISA. Melanin induced TNF-alpha, IL-6 and VEGF mRNA expression by the monocytes, PBMC and THP-1 cell line. On the protein level, melanin significantly induced TNF-alpha and IL-6 protein production and inhibited VEGF production by monocytes and PBMC. In the THP-1 cell line melanin induced production of all three cytokine proteins. These observations raise the prospects of using N. sativa L. melanin for treatment of diseases associated with imbalanced cytokine production and for enhancing cancer and other immunotherapies.

IL-17 enhances the net angiogenic activity and in vivo growth of human non-small cell lung cancer in SCID mice through promoting CXCR-2-dependent angiogenesis

In this study, we examined the biological action of IL-17 on human non-small cell lung cancer (NSCLC). Although IL-17 had no direct effect on the in vitro growth rate of NSCLC, IL-17 selectively augmented the secretion of an array of angiogenic CXC chemokines, including CXCL1, CXCL5, CXCL6, and CXCL8 but not angiostatic chemokines, by three different NSCLC lines. Endothelial cell chemotactic activity (as a measure of net angiogenic potential) was increased in response to conditioned medium from NSCLC stimulated with IL-17 compared with those from unstimulated NSCLC. Enhanced chemotactic activity was suppressed by neutralizing mAb(s) to CXCL1, CXCL5, and CXCL8 or to CXCR-2 but not to vascular endothelial growth factor-A. Transfection with IL-17 into NSCLC had no effect on the in vitro growth, whereas IL-17 transfectants grew more rapidly compared with controls when transplanted in SCID mice. This IL-17-elicited enhancement of NSCLC growth was associated with increased tumor vascularity. Moreover, treatment with anti-mouse CXCR-2-neutralizing Ab significantly attenuated the growth of both neomycin phosphotransferase gene-transfected and IL-17-transfected NSCLC tumors in SCID mice. A potential role for IL-17 in modulation of the human NSCLC phenotype was supported by the findings that, in primary NSCLC tissues, IL-17 expression was frequently detected in accumulating and infiltrating inflammatory cells and that high levels of IL-17 expression were associated with increased tumor vascularity. These results demonstrate that IL-17 increases the net angiogenic activity and in vivo growth of NSCLC via promoting CXCR-2-dependent angiogenesis and suggest that targeting CXCR-2 signaling may be a novel promising strategy to treat patients with NSCLC.

Targeting the extracellular domain of fibroblast growth factor receptor 3 with human single-chain Fv antibodies inhibits bladder carcinoma cell line proliferation

PURPOSE

Previous gene expression studies have shown that fibroblast growth factor receptor 3 (FGFR3) is overexpressed in early stages of bladder cancer. To study the potential use of therapeutic antibodies against FGFR3, we have produced a collection of human single-chain Fv (scFv) antibody fragments by using phage display libraries.

EXPERIMENTAL DESIGN

Two "naïve" semi-synthetic human scFv libraries were used to select antibodies against the extracellular domain of FGFR3alpha(IIIc). The reactivity of the selected scFvs with a recombinant FGFR3 was characterized by an enzyme immunoassay and surface plasmon resonance analysis and with RT112 bladder carcinoma cells by a fluorescence-activated cell sorter. The capacity of the selected scFvs to block RT112 cell proliferation was determined.

RESULTS

We have isolated six human scFv antibody fragments directed against FGFR3. These human scFvs specifically bound FGFR3, but not the homologous molecule FGFR1. Biacore analysis was used to determine the affinity constants, which ranged from 12 to 40 nmol/L. Competition analysis showed that the FGF9 ligand was able to block the binding of two scFvs, 3C and 7D, to FGFR3, whereas FGF1 only blocked 7D. Immunoprecipitation and flow cytometric analysis confirmed the specificity of the antibodies to native membrane FGFR3. Two scFvs, 3C and 7D, gave an strong immunofluorescence staining of RT112 cells. Moreover, they recognized equally well wild-type and mutant FGFR3 containing the activating mutation S249C. Furthermore, they blocked proliferation of RT112 cells in a dose- and FGF-dependent manner.

CONCLUSION

Our results suggest that these human anti-FGFR3 scFv antibodies may have potential applications as antitumoral agents in bladder cancer.

Herpes simplex virus amplicon delivery of a hypoxia-inducible soluble vascular endothelial growth factor receptor (sFlk-1) inhibits angiogenesis and tumor growth in pancreatic adenocarcinoma

BACKGROUND

Tumor hypoxia induces vascular endothelial growth factor (VEGF) expression, which stimulates angiogenesis and tumor proliferation. The VEGF signaling pathway is inhibited by soluble VEGF receptors (soluble fetal liver kinase 1; sFlk-1), which bind VEGF and block its interaction with endothelial cells. Herpes simplex virus (HSV) amplicons are replication-incompetent viruses used for gene delivery. We attempted to attenuate angiogenesis and inhibit pancreatic tumor growth through HSV amplicon-mediated expression of sFlk-1 under hypoxic control.

METHODS

A multimerized hypoxia-responsive enhancer (10 x HRE) was cloned upstream of the sFlk-1 gene (10 x HRE/sFlk-1). A novel HSV amplicon expressing 10 x HRE/sFlk-1 was genetically engineered (HSV10 x HRE/sFlk-1).Human pancreatic adenocarcinoma cells (AsPC1) were transduced with HSV10 x HRE/sFlk-1 and incubated in normoxia (21% oxygen) or hypoxia (1% oxygen). Capillary inhibition was evaluated by human umbilical vein endothelial cell assay. Western blot assessed sFlk-1 expression. AsPC1 flank tumor xenografts (n = 24) were transduced with HSV10 x HRE/sFlk-1.

RESULTS

Media from normoxic AsPC1 transduced with HSV10 x HRE/sFlk-1 yielded a 36% reduction in capillary formation versus controls (P < .05), whereas hypoxic AsPC1 yielded a 76% reduction (P < .005). Western blot of AsPC1 transduced with HSV10 x HRE/sFlk-1 demonstrated greater sFlk-1 expression in hypoxia versus normoxia. AsPC1 flank tumors treated with HSV10 x HRE/sFlk-1 exhibited a 59% reduction in volume versus controls (P < .000001).

CONCLUSIONS

HSV amplicon delivery of a hypoxia-inducible soluble VEGF receptor significantly reduces new vessel formation and tumor growth. Tumor hypoxia can thus be used to direct antiangiogenic therapy to pancreatic adenocarcinoma.

Antiangiogenic treatment with the three thrombospondin-1 type 1 repeats recombinant protein in an orthotopic human pancreatic cancer model

PURPOSE

This study investigates the antiangiogenesis and antitumor efficacy of a recombinant protein composed of the three type 1 repeats (3TSR) of thrombospondin-1 in an orthotopic human pancreatic cancer model and provides useful preclinical data for pancreatic cancer treatment.

EXPERIMENTAL DESIGN

Human pancreatic cancer cells (AsPC-1) were injected into the pancreas of severe combined immunodeficient mice. The animals were treated with 3TSR (3 mg per kg per day) or PBS for 3 weeks. Subsequently, the effects of 3TSR on tumor growth, microvessel density, cancer cell proliferation, apoptosis, and endothelial cell apoptosis were analyzed. The in vitro effects of 3TSR on human pancreatic cancer cells were also studied.

RESULTS

3TSR treatment significantly reduced angiogenesis and tumor growth of orthotopic pancreatic cancer. 3TSR-treated mice had a 69% reduction in tumor volume (316.6 +/- 79.3 versus 1,012.2 +/- 364.5 mm(3); P = 0.0001), and a significant increase in tumor necrotic area. After 3TSR treatment, both the vessel number and average microvessel size were significantly decreased, and microvessel density was decreased from 8.0% to 3.7% (P < 0.0001). The apoptotic rate of tumoral endothelial cells in 3TSR-treated tumors increased to 14.7% comparing to 4.2% in control tumors (P < 0.0001). 3TSR showed no direct effects on pancreatic cancer cell proliferation or apoptosis either in vivo or in vitro.

CONCLUSION

3TSR, a domain of a natural occurring angiogenesis inhibitor, showed potent therapeutic effect in pancreatic cancer by inhibiting tumor angiogenesis and may prove to be a promising agent for clinical pancreatic cancer treatment.

Evaluation of the fibroblast growth factor system as a potential target for therapy in human prostate cancer

Overexpression of fibroblast growth factors (FGFs) has been implicated in prostate carcinogenesis. FGFs function via their high-affinity interactions with receptor tyrosine kinases, FGFR1–4. Expression of FGFR1 and FGFR2 in prostate cancer (CaP) was not found to be associated with clinical parameters. In this report, we further investigated for abnormal FGFR expression in prostate cancer and explore their significance as a potential target for therapy. The expression levels of FGFR3 and FGFR4 in CaP were examined and corroborated to clinical parameters. FGFR3 immunoreactivity in benign prostatic hyperplasia (BPH) and CaP (n=26 and 57, respectively) had similar intensity and pattern. Overall, FGFR4 expression was significantly upregulated in CaP when compared to BPH. A significant positive correlation between FGFR4 expression and Gleason score was noted: Gleason score 7–10 tumours compared to BPH (P<0.0001, Fisher's exact test), Gleason score 4–6 tumours compared to BPH (P<0.0004), and Gleason 7–10 compared to Gleason 4–6 tumours (P<0.005). FGFR4 overexpression was associated with an unfavourable outcome with decreased disease-specific survival (P<0.04, log rank test). FGF-induced signalling is targeted using soluble FGF receptor (sFGFR), potent inhibitor of FGFR function. We have previously shown that sFGFR expression via a replication-deficient adenoviral vector (AdlllcRl) suppresses in vitro FGF-induced signalling and function in human CaP DU145 cells. We tested the significance of inhibiting FGF function along with conventional therapeutic modalities in CaP, and confirmed synergistic effects on in vitro cell growth (proliferation and colony formation) by combining sFGFR expression and treatment with either Paclitaxel (Taxol®) or γ-irradiation. In summary, our data support the model of FGF system as valid target for therapy in CaP.

Soluble Robo4 receptor inhibits in vivo angiogenesis and endothelial cell migration

Roundabout receptors are molecular guidance molecules that function by interaction with Slit proteins to regulate axon guidance, neuronal migration, and leukocyte chemotaxis. We recently isolated a novel roundabout gene, called Robo4, which is restricted in expression to the endothelium, notably in areas of angiogenesis. The aim of this study was to use the soluble extracellular domain of Robo4 as a probe of function in angiogenesis and endothelial biology. Thus, the soluble extracellular domain of the receptor (Robo4Fc) showed diverse in vivo and in vitro activities including 1) inhibition of angiogenesis in vivo in the rodent subcutaneous sponge model, 2) inhibition of tube formation in the rat aortic ring assay, 3) inhibition of VEGF- and bFGF-stimulated endothelial cell migration, and 4) inhibition of endothelial proliferation. To assess whether Robo4Fc was inhibiting Slit-mediated effects, we determined whether Robo4 and Slit interact. Recombinant Slits-1, -2, and -3 were shown by immunoprecipitation and BiaCore analysis to bind to Robo1 but not Robo4. Further study of the role of Robo4 in angiogenesis appears justified.