Halofuginone inhibits angiogenesis and growth in implanted metastatic rat brain tumor model--an MRI study

Correlation of Pattern of Invasion, Stromal Inflammation and Lymphovascular Invasion With Histopathological Grading in Oral Squamous Cell Carcinoma: A Retrospective Study

INTRODUCTION

Despite the progress in diagnostics and treatment modalities, the survival rate of oral squamous cell carcinoma (OSCC) patients has remained unchanged. Early diagnosis of the disease helps in better treatment and prognosis. Identifying clinicopathological and histopathological parameters that help predict disease progression is crucial.

OBJECTIVES

To assess the significance of various clinical and histopathological factors in OSCC and to correlate the patterns of invasion of tumour (POI), stromal inflammation, and lymphovascular invasion with the histopathological grading of OSCC.

MATERIALS AND METHODS

This study included 30 oral squamous cell carcinoma cases from 2015 to 2021. The surgically operated cases of OSCC were obtained from the archives of the Oral Pathology Department. The subjects were categorized according to the degree of differentiation of OSCC. The parameters like the pattern of invasion of tumour (POI), stromal inflammation, and lymphovascular invasion were assessed and correlated with the different histopathological grades of OSCC.

RESULTS

We observed a statistically significant correlation between the pattern of invasion and stromal inflammation with histopathological grades of OSCC. There was no significant association between lympho-vascular invasion and histopathological grades of OSCC.

CONCLUSION

We conclude that histopathological parameters like the pattern of invasion and stromal inflammation significantly impact different grades of OSCC. These parameters should be included in routine histo-pathological reports for predicting clinical outcomes and management of the disease.

Targeting the Integrated Stress Response in Cancer Therapy

The integrated stress response (ISR) is an evolutionarily conserved intra-cellular signaling network which is activated in response to intrinsic and extrinsic stresses. Various stresses are sensed by four specialized kinases, PKR-like ER kinase (PERK), general control non-derepressible 2 (GCN2), double-stranded RNA-dependent protein kinase (PKR) and heme-regulated eIF2α kinase (HRI) that converge on phosphorylation of serine 51 of eIF2α. eIF2α phosphorylation causes a global reduction of protein synthesis and triggers the translation of specific mRNAs, including activating transcription factor 4 (ATF4). Although the ISR promotes cell survival and homeostasis, when stress is severe or prolonged the ISR signaling will shift to regulate cellular apoptosis. We review the ISR signaling pathway, regulation and importance in cancer therapy.

Effects of corticosteroids vs halofuginone on vocal fold wound healing in an ovine model

OBJECTIVES

To evaluate antifibrotic effects of corticosteroids and halofuginone, a small molecule inhibitor of Smad3, in an ovine model of vocal fold (VF) injury.

METHODS

Thirty sheep, using a paired study design, underwent controlled right VF injury by biopsy and then were treated with either no treatment, oral dexamethasone, intralesional triamcinolone, or oral halofuginone. Larynges were evaluated for histological evidence of fibrosis, immunohistochemical presence of Smad3, and vibratory parameters. Outcomes were compared across treatment groups.

RESULTS

Following injury, VF collagen density decreased in both halofuginone-treated and dexamethasone-treated sheep but not in triamcinolone treated sheep. A significant difference was noted between halofuginone and triamcinolone treated sheep (27.8% vs 37%, P = .017). Elastin was preserved postinjury by halofuginone treatment in contrast with all steroid treated animals where significant loss of elastin was noted (P <.05). Smad3 staining was up-regulated at all injury sites compared to normal left VFs however halofuginone and dexamethasone treatment reduced Smad3 activity significantly whereas triamcinolone treatment did not (P <.05). Ex-vivo stroboscopic evaluation demonstrated mucosal wave in all excised larynges with a normalized glottal gap less than 3, suggesting adequate glottal closure.

CONCLUSIONS

VF injury in an ovine model results in a wound response able to be modified by Smad3 inhibitor, halofuginone, with benefit to vibratory function. Halofuginone treated sheep demonstrated reduced collagenization of lamina propria with greater elastin density after injury, than sheep treated with either steroid medication. These data support this pathway as a suitable target for manipulation to prevent or reverse fibrosis in the glottis and restore voice quality.Level of Evidence: NA.

Histopathological Factors in Oral Squamous Cell Carcinoma-Should a Clinician Look Beyond Clinical Staging?

PURPOSE

Several researchers have proposed and investigated the prognostic implications of various parameters, but have failed to provide concrete evidence regarding the inclusion or exclusion of histopathological features while clinically managing an oral squamous cell carcinoma (OSCC) case. The study purpose was to measure the prognostic values of a set of key histologic features and its association with its clinical outcome-5-year survival.

MATERIALS AND METHODS

This is a prospective cohort study and the sample was composed of patients treated for OSCC (April 2014 - March 2015). The predictor variables included pattern of tumor invasion (POI), stromal inflammation, angiogenesis, and vascular invasion with the outcome being survival of subjects observed over this 5-year period. Sociodemographic data (age, sex, marital status, systemic disease, habits etc), clinical staging and TNM staging were also recorded. We used multivariate regression analysis for predictor analysis; Kaplan-Meier survival curves and Cox hazard modeling was also performed using the data.

RESULTS

This article includes 50 subjects with a mean age of 54.94 years and 58% were male and their characteristics collected at the baseline and at a 12-, 24-, 36-, 48-, and 60-month follow-up. The overall 5-year survival was 48%. We saw a significant association between N-stage and POI (0.027), T-stage and mean vascular density (0.042), and T-stage and vascular invasion (0.046). POI, angiogenesis, and vascular invasion were found as significant predictors of overall 5-year survival (P < .001).

CONCLUSIONS

This study shows that histopathological parameters such as POI are important while determining the clinical outcome of OSCC. Histopathological parameters such as angiogenesis and vascular invasion can provide valuable information about the overall survival and prognosis.

Pattern of tumor invasion, stromal inflammation, angiogenesis and vascular invasion in oral squamous cell carcinoma - A prognostic study

INTRODUCTION

Oral cancer is one of the leading causes of mortality, and its worsening impact on the society has revealed the danger it poses in the coming future. Several researchers proposed and investigated the prognostic implications of various clinicopathologic and histopathologic parameters.

AIM AND OBJECTIVES

The aim of this study--assessing significance of histopathological features like pattern of tumor invasion, stromal inflammation, angiogenesis and vascular invasion on the clinical outcome of oral squamous cell carcinoma any possible correlations between the parameters, TNM Staging and prognosis were assessed and evaluated for a 5-year period.

MATERIALS AND METHODS

This study includes description of 50 diagnosed cases (mean age: 61.40, 29 males, and 21 females) of oral squamous cell carcinoma and their characteristics collected at baseline and at a 12-month follow up. The cases were grouped on the basis of their histological grade (well-differentiated, moderately differentiated, and poorly-differentiated).

RESULTS

All the data collected was tabulated in a baseline descriptive table, and all the parameters were compared between the 3 different histological groups. On cross-tabulations we found statistical significant difference the parameters of stromal inflammation with recurrence, clinical stage with T-stage, T-stage with N-stage, and N-stage with clinical stage. On analysis of the follow up we found 16 patients (32%) with recurrence and 9 patients (18%) succumb to the disease.

CONCLUSION

This study provides a significant insight on the importance of a combined histopathological analysis and clinical staging process to deliver an accurate prognostic opinion and also subsequently effect the treatment protocol.

Significance of halofuginone in esophageal squamous carcinoma cell apoptosis through HIF-1α-FOXO3a pathway

Halofuginone (HF) from Dichroa febrifuga has shown therapeutic potential in hepatocellular, lung and colorectal cancer cell models. Evidence has also indicated that HF plays roles in caustic induced esophageal strictures and oxidative injury. However, the role of HF in esophageal squamous carcinoma (ESCC) remains unclear. In this study, we investigated HF actions and mechanisms during ESCC cell apoptosis. We observed different HF concentrations (5, 10 and 20 nM) inhibited ESCC cell survival in a time and dose-dependent manner. HF treatment markedly induced KYSE-30 and TE-1 cell apoptosis, and caspase-3 activity. Apoptosis related protein Bax expression was dramatically increased, whereas Bcl-2 levels were reduced in KYSE-30 and TE-1 cells, after HF exposure. Also, we showed that HF treatment induced DNA damage by promoting γH₂AX, pATM and pATR expression. HF treatment also reduced hypoxia-inducible factor-1α (HIF-1α) and forkhead box class O 3a (FOXO3a) expression in KYSE-30 and TE-1 cells. We also showed that HF inhibited FOXO3a expression, but this was dependent on HIF-1α inhibition. Finally, FOXO3a overexpression reversed HF induced cell survival inhibition, cell apoptosis and DNA damage. FOXO3a knockdown enhanced the effects of HF on cell survival, cell apoptosis and DNA damage. In summary, HF plays inhibitory roles in ESCC cell apoptosis, via HIF-1α-FOXO3a-dependent signaling. These data support the notion that HF could act as an effective therapeutic reagent towards ESCC.

Anticarcinogenic effects of halofuginone on lung-derived cancer cells

Malignant mesothelioma is a rare but aggressive form of malignancy, which is difficult to diagnose and is resistant to current chemotherapeutic treatment options. Molecular techniques have been used to investigate the mechanisms of action and the beneficial therapeutic effects of halofuginone (HF) in several cancers but not malignant mesotheliomas. In this study, the antiproliferative and apoptotic effects of HF were investigated through its ability to deregulate EGFR downstream signalling cascade proteins in the pathologically aggressive malignant mesothelioma and non-small-cell lung cancer cells. We showed that administration of HF at nanomolar concentrations induced a dose-dependent reduction in the viability of cancer cells, made cell cycle arrest, inhibited proliferation of cancer cells via STAT3 and ERK1/2 pathways and triggered the apoptotic cascade via p38MAPK. We demonstrated that the apoptotic cell death mechanism was mediated by enhanced activation of caspase-3 and concomitant PARP cleavage, downregulation of Bcl-2 and upregulation of Bax in both malignant mesothelioma and lung cancer cells. In particular, we demonstrated that cancer cells were more sensitive to HF treatment than normal mesothelial cells. Taken together, this study suggests that HF exerts its anticancer effects in lung-derived cancers by targeting signal transduction pathways mainly through deregulation of ERK1/2, STAT3 and p38MAPK to reduce cancer cell viability, induce cell cycle arrest and apoptotic cell death. Thus, HF might be considered as a potential agent against malignant mesothelioma and/or lung cancer cells.

Proline Metabolism in Tumor Growth and Metastatic Progression

Cancer cells show a formidable capacity to survive under stringent conditions, to elude mechanisms of control, such as apoptosis, and to resist therapy. Cancer cells reprogram their metabolism to support uncontrolled proliferation and metastatic progression. Phenotypic and functional heterogeneity are hallmarks of cancer cells, which endow them with aggressiveness, metastatic capacity, and resistance to therapy. This heterogeneity is regulated by a variety of intrinsic and extrinsic stimuli including those from the tumor microenvironment. Increasing evidence points to a key role for the metabolism of non-essential amino acids in this complex scenario. Here we discuss the impact of proline metabolism in cancer development and progression, with particular emphasis on the enzymes involved in proline synthesis and catabolism, which are linked to pathways of energy, redox, and anaplerosis. In particular, we emphasize how proline availability influences collagen synthesis and maturation and the acquisition of cancer cell plasticity and heterogeneity. Specifically, we propose a model whereby proline availability generates a cycle based on collagen synthesis and degradation, which, in turn, influences the epigenetic landscape and tumor heterogeneity. Therapeutic strategies targeting this metabolic-epigenetic axis hold great promise for the treatment of metastatic cancers.

Antiangiogenic Effect of Alkaloids

Alkaloids are among the natural phytochemicals contained in functional foods and nutraceuticals and have been suggested for the prevention and/or management of oxidative stress and inflammation-mediated diseases. In this review, we aimed to describe the effects of alkaloids in angiogenesis, the process playing a crucial role in tumor growth and invasion, whereby new vessels form. Antiangiogenic compounds including herbal ingredients, nonherbal alkaloids, and microRNAs can be used for the control and treatment of cancers. Several lines of evidence indicate that alkaloid-rich plants have several interesting features that effectively inhibit angiogenesis. In this review, we present valuable data on commonly used alkaloid substances as potential angiogenic inhibitors. Different herbal and nonherbal ingredients, introduced as antiangiogenesis agents, and their role in angiogenesis-dependent diseases are reviewed. Studies indicate that angiogenesis suppression is exerted through several mechanisms; however, further investigations are required to elucidate their precise molecular and cellular mechanisms, as well as potential side effects.

Halofuginone inhibits TGF-β/BMP signaling and in combination with zoledronic acid enhances inhibition of breast cancer bone metastasis

More efficient therapies that target multiple molecular mechanisms are needed for the treatment of incurable bone metastases. Halofuginone is a plant alkaloid-derivative with antiangiogenic and antiproliferative effects. Here we demonstrate that halofuginone is an effective therapy for the treatment of bone metastases, through multiple actions that include inhibition of TGFβ and BMP-signaling.

Halofuginone blocked TGF-β-signaling in MDA-MB-231 and PC3 cells showed by inhibition of TGF-β–induced Smad-reporter, phosphorylation of Smad-proteins, and expression of TGF-β-regulated metastatic genes. Halofuginone increased inhibitory Smad7-mRNA and reduced TGF-β-receptor II protein. Proline supplementation but not Smad7-knockdown reversed halofuginone-inhibition of TGF-β-signaling. Halofuginone also decreased BMP-signaling. Treatment of MDA-MB-231 and PC3 cells with halofuginone reduced the BMP-Smad-reporter (BRE)₄, Smad1/5/8-phosphorylation and mRNA of the BMP-regulated gene Id-1. Halofuginone decreased immunostaining of phospho-Smad2/3 and phospho-Smad1/5/8 in cancer cells in vivo.

Furthermore, halofuginone decreased tumor-take and growth of orthotopic-tumors. Mice with breast or prostate bone metastases treated with halofuginone had significantly less osteolysis than control mice. Combined treatment with halofuginone and zoledronic-acid significantly reduced osteolytic area more than either treatment alone. Thus, halofuginone reduces breast and prostate cancer bone metastases in mice and combined with treatment currently approved by the FDA is an effective treatment for this devastating complication of breast and prostate-cancer.

Venous component in scar penetrating neovascularisation

BACKGROUND

The impact of old scar tissue on the venous anatomy of a flap's pedicle is an important question in reconstructive surgery. This study tried to investigate the venous component in scar penetrating neovascularisation.

METHODS

Fifty Sprague-Dawley rats were used in this experimental study. Two experimental groups were designed. In the first group, incisions were performed over the epigastric flap pedicles. In the second group, 1 cm wide segments were excised over the pedicles. Ten weeks after the initial operations, angiographies and histological examinations were performed. A control group was used to demonstrate the normal arterial and venous anatomy of the pedicle.

RESULTS

Arterial angiographies revealed that axial pattern arteries were visible in the incision group as opposed to the excision group. Although venous angiographies showed that there were more venous capillary formations in the incision group, none of the experimental groups had regenerated a vein with an axial pattern. Histological examinations revealed that venous vessel formations were significantly less in the distal samples of the experimental groups when compared to the control group (p < 0.05).

CONCLUSIONS

In this study, it has been observed that arterial pedicles do regenerate over old incision scars as opposed to veins. In the excision scars neither arterial or venous restoration of the axial pedicle was possible. In these cases, only a random type of limited circulation was restored.

Halofuginone inhibits phosphorylation of SMAD-2 reducing angiogenesis and leukemia burden in an acute promyelocytic leukemia mouse model

Background

Halofuginone (HF) is a low-molecular-weight alkaloid that has been demonstrated to interfere with Metalloproteinase-2 (MMP-2) and Tumor Growth Factor-β (TGF-β) function and, to present antiangiogenic, antiproliferative and proapoptotic properties in several solid tumor models. Based on the fact that high levels of Vascular Endothelial Growth Factor (VEGF) and increased angiogenesis have been described in acute myeloid leukemia and associated with disease progression, we studied the in vivo effects of HF using an Acute Promyelocytic Leukemia (APL) mouse model.

Methods

NOD/SCID mice were transplanted with leukemic cells from hCG-PML/RARA transgenic mice (TM) and treated with HF 150 μg/kg/day for 21 days. The leukemic infiltration and the percentage of VEGF+ cells were evaluated by morphology and flow cytometry. The effect of HF on the gene expression of several pro- and antiangiogenic factors, phosphorylation of SMAD2 and VEGF secretion was assessed in vitro using NB4 and HUVEC cells.

Results

HF treatment resulted in hematological remission with decreased accumulation of immature cell and lower amounts of VEGF in BM of leukemic mice. In vitro, HF modulated gene expression of several pro- and antiangiogenic factors, reduced VEGF secretion and phosphorylation of SMAD2, blocking TGF-β-signaling.

Conclusion

Taken together, our results demonstrate that HF inhibits SMAD2 signaling and reduces leukemia growth and angiogenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0181-2) contains supplementary material, which is available to authorized users.

Animal models of tumour-associated epilepsy

Brain tumours cause a sizeable proportion of epilepsies in adulthood, and actually can be etiologically responsible also for childhood epilepsies. Conversely, seizures are often first clinical signs of a brain tumour. Nevertheless, several issues of brain-tumour associated seizures and epilepsies are far from understood, or clarified regarding clinical consensus. These include both the specific mechanisms of epileptogenesis related to different tumour types, the possible relationship between malignancy and seizure emergence, the interaction between tumour mass and surrounding neuronal networks, and - not least - the best treatment options depending on different tumour types. To investigate these issues, experimental models of tumour-induced epilepsies are necessary. This review concentrates on the description of currently used models, focusing on methodological aspects. It highlights advantages and shortcomings of these models, and identifies future experimental challenges.

Monitoring brain tumor vascular heamodynamic following anti-angiogenic therapy with advanced magnetic resonance imaging in mice

Advanced MR imaging methods have an essential role in classification, grading, follow-up and therapeutic management in patients with brain tumors. With the introduction of new therapeutic options, the challenge for better tissue characterization and diagnosis increase, calling for new reliable non-invasive imaging methods. In the current study we evaluated the added value of a combined protocol of blood oxygen level dependent (BOLD) imaging during hyperoxic challenge (termed hemodynamic response imaging (HRI)) in an orthotopic mouse model for glioblastoma under anti-angiogenic treatment with B20-4.1.1, an anti-VEGF antibody. In glioblastoma tumors, the elevated HRI indicated progressive angiogenesis as further confirmed by histology. In the current glioblastoma model, B20-treatment caused delayed tumor progression with no significant changes in HRI yet with slightly reduced tumor vascularity as indicated by histology. Furthermore, fewer apoptotic cells and higher proliferation index were detected in the B20-treated tumors compared to control-treated tumors. In conclusion, HRI provides an easy, safe and contrast agent free method for the assessment of the brain hemodynamic function, an additionally important clinical information.

Plant-derived anticancer agents: a promising treatment for bone metastasis

Bone metastasis is a very frequent complication of advanced cancer, and it remains an incurable disease. Current therapies that have been approved for the treatment of bone metastases delay the occurrence of skeletal-related events and can extend the patient's lifespan by a few years. However, they will not cure or cause the regression of established bone metastases, and new side effects are emerging after prolonged treatment. Thus, new therapies are severely needed. There are compelling evidences from in vitro and in vivo preclinical studies that support the use of compounds derived from plants to treat several forms of cancers including bone metastasis. More than 25% of the drugs used during the past 20 years were directly derived from plants, whereas another 25% are chemically altered natural products. Still, only 5-15% of the ∼250 000 higher plants have ever been investigated for bioactive compounds. There is a growing interest for the study of anticancer drugs with relatively low side effects that target specific key signaling pathways that control the establishment and progression of the cancer metastasis. Therefore, further studies are needed to identify new natural compounds with high efficiency in cancer prevention and treatment. Extensive reviews about plant-derived agents and their use in cancer have been published, but none when it comes to the treatment of bone metastases. Only a few of these compounds have been evaluated for the treatment of bone metastasis; here we describe some of the most prominent ones that are having the potential to reach the clinic soon.

The chemistry and biology of febrifugine and halofuginone

The trans-2,3-disubstituted piperidine, quinazolinone-containing natural product febrifugine (also known as dichroine B) and its synthetic analogue, halofuginone, possess antimalarial activity. More recently studies have also shown that halofuginone acts as an agent capable of reducing fibrosis, an indication with clinical relevance for several disease states. This review summarizes historical isolation studies and the chemistry performed which culminated in the correct structural elucidation of naturally occurring febrifugine and its isomer isofebrifugine. It also includes the range of febrifugine analogues prepared for antimalarial evaluation, including halofuginone. Finally, a section detailing current opinion in the field of halofuginone's human biology is included.

Targeting TGFβ signaling to inhibit fibroblast activation as a therapy for fibrosis and cancer: effect of halofuginone

The fibroblast to myofibroblast transition in wound healing, fibrosis and cancer has emerged as a viable target for pharmacological intervention. The myofibroblasts acquire specific characteristics because of differences in origin and localization, but also share common properties, such as TGFβ signaling. Halofuginone, an inhibitor of the Smad3 phosphorylation, downstream of the TGFβ signaling, inhibits the activation of fibroblasts and their ability to synthesize the extracellular matrix, regardless of their origin or location. Halofuginone prevented the new and stimulated resolution of pre-existing fibrosis of several organs and inhibited the development and progression of various tumors. Moreover, halofuginone synergizes with chemotherapy and reduces the need for high doses of toxic compounds without impairing the treatment efficacy. In fibrosis, where the myofibroblasts are the major participant, halofuginone can be used as a single therapy, whereas in cancer it should be considered in combination with other therapies that affect the tumor cells via different modalities.

MRI multiparametric hemodynamic characterization of the normal brain

Characterization of the brain's vascular system is of major clinical importance in the assessment of patients with cerebrovascular disease. The aim of this study was to characterize brain hemodynamics using multiparametric methods and to obtain reference values from the healthy brain. A multimodal magnetic resonance imaging (MRI) study was performed in twenty healthy subjects, including dynamic susceptibility contrast imaging and blood oxygen level dependence (BOLD) during hypercapnia and carbogen challenges. Brain tissues were defined using unsupervised cluster analysis based on these three methods, and several hemodynamic parameters were calculated for gray matter (GM), white matter (WM), blood vessels and dura (BVD); the three main vascular territories within the GM; and arteries and veins defined within the BVD cluster. The carbogen challenge produced a BOLD signal twice as high as the hypercapnia challenge, in all brain tissues. The three brain tissues differed significantly from each other in their hemodynamic characteristics, supporting the graded vascularity of the tissues, with BVD>GM>WM. Within the GM cluster, a significant delay of ∼1.2 s of the bolus arrival time was detected within the posterior cerebral artery territory relative to the middle and anterior cerebral artery territories. No differences were detected between right and left middle cerebral artery territories for all hemodynamic parameters. Within the BVD cluster, a significant delay of ∼1.9 s of the bolus arrival time was detected within the veins relative to the arteries. This parameter enabled to differentiate between the various blood vessels, including arteries, veins and choroid plexus. This study provides reference values for several hemodynamic parameters, obtained from healthy brains, and may be clinically important in the assessment of patients with various vascular pathologies.

Hemodynamic response imaging: a potential tool for the assessment of angiogenesis in brain tumors

Blood oxygenation level dependence (BOLD) imaging under either hypercapnia or hyperoxia has been used to study neuronal activation and for assessment of various brain pathologies. We evaluated the benefit of a combined protocol of BOLD imaging during both hyperoxic and hypercapnic challenges (termed hemodynamic response imaging (HRI)). Nineteen healthy controls and seven patients with primary brain tumors were included: six with glioblastoma (two newly diagnosed and four with recurrent tumors) and one with atypical-meningioma. Maps of percent signal intensity changes (ΔS) during hyperoxia (carbogen; 95%O2+5%CO2) and hypercapnia (95%air+5%CO2) challenges and vascular reactivity mismatch maps (VRM; voxels that responded to carbogen with reduced/absent response to CO2) were calculated. VRM values were measured in white matter (WM) and gray matter (GM) areas of healthy subjects and used as threshold values in patients. Significantly higher response to carbogen was detected in healthy subjects, compared to hypercapnia, with a GM/WM ratio of 3.8 during both challenges. In patients with newly diagnosed/treatment-naive tumors (n = 3), increased response to carbogen was detected with substantially increased VRM response (compared to threshold values) within and around the tumors. In patients with recurrent tumors, reduced/absent response during both challenges was demonstrated. An additional finding in 2 of 4 patients with recurrent glioblastoma was a negative response during carbogen, distant from tumor location, which may indicate steal effect. In conclusion, the HRI method enables the assessment of blood vessel functionality and reactivity. Reference values from healthy subjects are presented and preliminary results demonstrate the potential of this method to complement perfusion imaging for the detection and follow up of angiogenesis in patients with brain tumors.

Halofuginone inhibits the establishment and progression of melanoma bone metastases

TGF-β derived from bone fuels melanoma bone metastases by inducing tumor secretion of prometastatic factors that act on bone cells to change the skeletal microenvironment. Halofuginone is a plant alkaloid derivative that blocks TGF-β signaling with antiangiogenic and antiproliferative properties. Here, we show for the first time that halofuginone therapy decreases development and progression of bone metastasis caused by melanoma cells through the inhibition of TGF-β signaling. Halofuginone treatment of human melanoma cells inhibited cell proliferation, phosphorylation of SMAD proteins in response to TGF-β, and TGF-β-induced SMAD-driven transcription. In addition, halofuginone reduced expression of TGF-β target genes that enhance bone metastases, including PTHrP, CTGF, CXCR4, and IL11. Also, cell apoptosis was increased in response to halofuginone. In nude mice inoculated with 1205 Lu melanoma cells, a preventive protocol with halofuginone inhibited bone metastasis. The beneficial effects of halofuginone treatment were comparable with those observed with other anti-TGF-β strategies, including systemic administration of SD208, a small-molecule inhibitor of TGF-β receptor I kinase, or forced overexpression of Smad7, a negative regulator of TGF-β signaling. Furthermore, mice with established bone metastases treated with halofuginone had significantly less osteolysis than mice receiving placebo assessed by radiography. Thus, halofuginone is also effective in reducing the progression of melanoma bone metastases. Moreover, halofuginone treatment reduced melanoma metastasis to the brain, showing the potential of this novel treatment against cancer metastasis.

Improved efficacy of a novel anti-angiogenic drug combination (TL-118) against colorectal-cancer liver metastases; MRI monitoring in mice

BACKGROUND

The poor prognosis of patients with colorectal-cancer liver metastases (CRLM) and the insufficiency of available treatments have raised the need for alternative curative strategies. We aimed to assess the therapeutic potential of TL-118, a new anti-angiogenic drug combination, for CRLM treatment, in a mouse model.

METHODS

The therapeutic potential of TL-118 was evaluated and compared with B20-4.1.1 (B20; anti-VEGF antibody) and rapamycin in CRLM-bearing mice. Tumour progression and the vascular changes were monitored by MRI. Additionally, mice survival, cell proliferation, apoptosis and vessel density were evaluated.

RESULTS

This study demonstrated an unequivocal advantage to TL-118 therapy by significantly prolonging survival (threefold) and reducing metastasis perfusion and vessel density (ninefold). The underlying mechanism for TL-118-treatment success was associated with hepatic perfusion attenuation resulting from reduced nitric-oxide (NO) serum levels as elucidated by using hemodynamic response imaging (HRI, a functional MRI combined with hypercapnia and hyperoxia). Further, systemic hepatic perfusion reduction during the initial treatment phase by adding NO inhibitor has proven to be essential for reaching maximal therapeutic effects for both TL-118 and B20.

CONCLUSION

TL-118 harbours a potential clinical benefit to CLRM patients. Moreover, the reduction of hepatic perfusion at early stages of anti-angiogenic therapies by adding NO inhibitor is crucial for achieving maximal anti-tumour effects.

Local inhibition of angiogenesis by halofuginone coated silicone materials

Anti-angiogenic therapy is a promising approach for the treatment of increased angiogenesis in certain diseases. We aimed to investigate the local anti-angiogenic effect of silicone implants coated with Halofuginone, an angiogenesis inhibitor that inhibits synthesis of collagen-type-I and matrix metalloproteinases. The degree of angiogenesis was observed after implantation of surface modified Halofuginone eluting silicone implants into a submuscular pocket in rats over a period of 3 months. Subsequently, key mediators of angiogenesis (TGF-beta-1, bFGF, COL1A1, MMP-2, MMP-9, VEGF and PDGF) were established by immunohistological staining and RT-PCR and statistically evaluated. In comparison to uncoated silicone implants, Halofuginone eluting silicone implants lead to a significant local decrease of angiogenesis. Halofuginone eluting hybrid surface silicone implants have a significant local anti-angiogenic effect by down-regulating the expression activity of key mediators of angiogenesis.

Halofuginone inhibits multiple myeloma growth in vitro and in vivo and enhances cytotoxicity of conventional and novel agents

Multiple Myeloma (MM), a malignancy of plasma cells, remains incurable despite the use of conventional and novel therapies. Halofuginone (HF), a synthetic derivative of quinazolinone alkaloid, has recently been shown to have anti-cancer activity in various preclinical settings. This study demonstrated the anti-tumour activity of HF against a panel of human MM cell lines and primary patient-derived MM cells, regardless of their sensitivity to conventional therapy or novel agents. HF showed anti-MM activity in vivo using a myeloma xenograft mouse model. HF suppressed proliferation of myeloma cells alone and when co-cultured with bone marrow stromal cells. Similarly, HF induced apoptosis in MM cells even in the presence of insulin-like growth factor 1 or interleukin 6. Importantly, HF, even at high doses, did not induce cytotoxicity against CD40 activated peripheral blood mononuclear cells from normal donors. HF treatment induced accumulation of cells in the G(0) /G(1) cell cycle and induction of apoptotic cell death associated with depletion of mitochondrial membrane potential; cleavage of poly (ADP-ribose) polymerase and caspases-3, 8 and 9 as well as down-regulation of anti-apoptotic proteins including Mcl-1 and X-IAP. Multiplex analysis of phosphorylation of diverse components of signalling cascades revealed that HF induced changes in P38MAPK activation; increased phosphorylation of c-jun, c-jun NH(2)-terminal kinase (JNK), p53 and Hsp-27. Importantly, HF triggered synergistic cytotoxicity in combination with lenalidomide, melphalan, dexamethasone, and doxorubicin. Taken together, these preclinical studies provide the preclinical framework for future clinical studies of HF in MM.

Halofuginone has anti-proliferative effects in acute promyelocytic leukemia by modulating the transforming growth factor beta signaling pathway

Promyelocytic leukemia-retinoic acid receptor alpha (PML-RARα) expression in acute promyelocytic leukemia (APL) impairs transforming growth factor beta (TGFβ) signaling, leading to cell growth advantage. Halofuginone (HF), a low-molecular-weight alkaloid that modulates TGFβ signaling, was used to treat APL cell lines and non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice subjected to transplantation with leukemic cells from human chorionic gonadotrophin-PML-RARα transgenic mice (TG). Cell cycle analysis using incorporated bromodeoxyuridine and 7-amino-actinomycin D showed that, in NB4 and NB4-R2 APL cell lines, HF inhibited cellular proliferation (P<0.001) and induced apoptosis (P = 0.002) after a 24-hour incubation. Addition of TGFβ revealed that NB4 cells were resistant to its growth-suppressive effects and that HF induced these effects in the presence or absence of the cytokine. Cell growth inhibition was associated with up-regulation of TGFβ target genes involved in cell cycle regulation (TGFB, TGFBRI, SMAD3, p15, and p21) and down-regulation of MYC. Additionally, TGFβ protein levels were decreased in leukemic TG animals and HF in vivo could restore TGFβ values to normal. To test the in vivo anti-leukemic activity of HF, we transplanted NOD/SCID mice with TG leukemic cells and treated them with HF for 21 days. HF induced partial hematological remission in the peripheral blood, bone marrow, and spleen. Together, these results suggest that HF has anti-proliferative and anti-leukemic effects by reversing the TGFβ blockade in APL. Since loss of the TGFβ response in leukemic cells may be an important second oncogenic hit, modulation of TGFβ signaling may be of therapeutic interest.

Noninvasive multiparametric imaging of metastasis-permissive microenvironments in a human prostate cancer xenograft

Metastasis continues to be one of the major causes of mortality from prostate cancer. Because human malignant cell lines metastasize more readily from orthotopic sites than from heterotopic sites, to identify metastasis-permissive tumor microenvironments, we used noninvasive imaging to compare the in vivo vascular, metabolic, and physiologic characteristics of a human prostate cancer xenograft implanted orthotopically in the prostate or s.c. in the flank. Hypoxia was detected in these xenografts by placing an enhanced green fluorescence protein optical reporter under the control of a hypoxia response element. A multiparametric analysis of hypoxia, extracellular pH, vascularization, and metabolism provided a characterization of environments that are permissive for metastasis to occur. We found that orthotopic tumors, which metastasized more easily, were characterized by higher vascular volume, permeability, and total choline and a more acidic extracellular pH. Interestingly, metastatic deposits in the lymph nodes as well as cancer cells in ascites fluid were found to be hypoxic, explaining, in part, the refractory nature of metastatic disease. These results also provide the basis for clinically translatable noninvasive imaging markers for predicting metastatic risk in prostate cancer.

Halofuginone enhances the radiation sensitivity of human tumor cell lines

Transforming growth factor beta (TGF-beta) is implicated in radiation-induced fibrosis of normal tissues in patients receiving radiotherapy. Inhibiting the TGF-beta signaling pathway by various means has been shown to reduce radiation-induced fibrosis in pre-clinical studies. The present study evaluated the effects of interfering with the TGF-beta signaling pathway on the radiosensitivity of selected human tumor cell lines using the plant-derived alkaloid, halofuginone. Halofuginone treatment inhibited cell growth, halted cell cycle progression, decreased radiation-induced DNA damage repair, and decreased TGF-beta receptor II protein levels, leading to increased cellular radiosensitization. These data further support the goal of manipulating the TGF-beta pathway to achieve a positive increase in the therapeutic gain in clinical radiotherapy.

An experimental model of brain metastasis of lung carcinoma

Most metastatic brain tumors originate from lung cancers. However, there has been relatively little progress on developing an experimental model of metastasis of lung cancer to the brain. By injecting Lewis lung carcinoma cells into the right internal carotid artery of C57BL/6NCrj mice, we succeeded in developing a model of metastatic brain tumors. In this model, carcinoma cells proliferated in the choroid plexus of the right lateral ventricle and formed a nodular tumor mass, while carcinoma cells in the cerebral parenchyma multiplied along the perivascular sheath without forming a nodular mass. Twelve days after injection, carcinoma cells spread into the left hemicerebrum. Fifteen days after injection, carcinoma cells could be seen in both hemispheres, along with intraventricular tumor formation. The maximum life span of mice with metastatic brain tumors was 22 days. Our model essentially replicated the general process of metastatic cancer and may have a significant role in further research on brain metastasis of lung cancer.

Liver response to hemorrhagic shock and subsequent resuscitation: MRI analysis

The liver is a target for injury in low flow states. Markers of liver injury are either invasive or not rapidly responding. Magnetic resonance imaging (MRI) may offer a noninvasive alternative to evaluate liver injury due to reduced perfusion. Recently, we reported an MRI method (functional MRI [fMRI]) that enables us to follow liver perfusion by changing the enrichment of inspired gas (air, air-5% carbon dioxide, 95% oxygen-5% carbon dioxide). Rats were subjected to hemorrhagic shock (HS) (bleeding to a MAP of 25 mmHg) and randomized to no resuscitation or resuscitation with Ringer lactate (RL) or adrenaline infusion targeted to a MAP of 50 mmHg or baseline. Significantly decreased fMRI responses to hyperoxia and hypercapnia were observed immediately after HS. Liver enzymes levels, liver histology, and apoptosis assessments were normal immediately after hemorrhage, however, showed significant changes after 6 h. Functional MRI revealed that adrenaline, but not RL infusion, significantly (P < 0.01) improved liver perfusion. Similarly, liver injury, as assessed by liver enzyme levels, liver histology, and apoptosis, was attenuated to a greater extent with adrenaline resuscitation. No significant differences in liver perfusion and injury were noted between resuscitation to low (50 mmHg) versus high (baseline) MAP. This study shows that fMRI enables early assessment of changes in liver perfusion, resulting in liver injury or recovery, and therefore, it may be considered as a noninvasive, rapidly responding tool for following liver outcome subsequent to hemorrhage and resuscitation. Using fMRI, we showed that adrenaline may be preferable to RL as an initial measure to attenuate liver injury after HS.

Type I collagen expression contributes to angiogenesis and the development of deeply invasive cutaneous melanoma

Tumors are complex tissues composed of neoplastic cells, soluble and insoluble matrix components and stromal cells. Here we report that in melanoma, turn-over of type I collagen (Col(I)), the predominant matrix protein in dermal stroma affects melanoma progression. Fibroblasts juxtaposed to melanoma cell nests within the papillary dermis display high levels of Col(I) mRNA expression. These nests are enveloped by collagen fibers. In contrast, melanoma-associated fibroblasts within the reticular dermis express Col(I) mRNA at a level that is comparable to its expression in uninvolved dermis and reduced amount of collagen protein can be observed. To determine the significance of Col(I) expression in melanoma, we pharmacologically inhibited its transcription in a porcine cutaneous melanoma model by oral administration of halofuginone. When administered before melanoma development, it reduced melanoma incidence and diminished the transition from microinvasive toward deeply invasive growth by limiting the development of a tumor vasculature. Whereas invasive melanoma growth has been correlated with increased blood vessel density previously, our data for the first time demonstrate that the proangiogenic effect of Col(I) expression by fibroblasts and vascular cells precedes the development of invasive melanomas in a de novo tumor model.

Smad7 sensitizes tumor necrosis factor induced apoptosis through the inhibition of antiapoptotic gene expression by suppressing activation of the nuclear factor-kappaB pathway

Although tumor necrosis factor (TNF) induces apoptosis and cell death in many tumor cells, some cancer cells are still resistant to the TNF-induced death signal. In this report, we showed that Smad7, an inhibitory Smad of transforming growth factor-beta (TGF-beta) signaling, can overcome the TNF resistance in human breast and gastric cancer cells. Overexpression of Smad7 induces the degradation of poly(ADP-ribose) polymerase and the activation of caspase cascade. Although c-Jun NH2-terminal kinase (JNK) signaling is involved in TNF-induced cell death, the expression of Smad7 does not synergize the activation of JNK. However, the activation of nuclear factor-kappaB (NF-kappaB), the cell survival factor, is markedly decreased in Smad7-stable cells. Furthermore, the expression of antiapoptotic target genes of NF-kappaB is significantly reduced in accordance with the level of Smad7. In addition, Smad7 mediates the inhibitory activity of TGF-beta on TNF-induced NF-kappaB activation and the synergistic activity of TGF-beta on TNF-induced apoptosis. These findings suggest that Smad7 sensitizes the tumor cells to TNF-induced apoptosis through the inhibition of expression of antiapoptotic NF-kappaB target genes.

Functional MR imaging during hypercapnia and hyperoxia: noninvasive tool for monitoring changes in liver perfusion and hemodynamics in a rat model

PURPOSE

To prospectively assess functional magnetic resonance (MR) imaging during hypercapnia and hyperoxia for monitoring changes in liver perfusion and hemodynamics in rats.

MATERIALS AND METHODS

All experiments were performed with approval of an animal care and use committee. Functional T2*-weighted gradient-echo MR images of the rat liver were acquired during hyperoxia and graded hypercapnia (n=24). Additional images were acquired during portal vein ligation (n=4), induced hypovolemia (n=5), and 70% hepatectomy (n=5). Hypercapnic effects were confirmed with Doppler ultrasonography and with gadopentetate dimeglumine. Differences between groups were analyzed by using Wilcoxon rank sum test, except for the graded hypercapnia, for which one-way analysis of variance was used.

RESULTS

Liver signal intensity (SI) increased due to hyperoxia; the percentage change in SI was seven times greater than that in muscle tissue; this reflects higher vascularity of the liver. Liver SI decreased due to hypercapnia; the percentage change in SI was negative in the liver but positive in the muscle (P<.001). Induced hypovolemia resulted in considerable decreases in functional MR imaging response; this reflects lower liver perfusion. Clinical applicability of the functional MR imaging method was proved by monitoring changes in liver perfusion that resulted from liver resection.

CONCLUSION

In the liver, the magnitude of the percentage change in SI induced by hypercapnia and hyperoxia reflects changes in total blood volume; whereas percentage change in SI values induced by hypercapnia from a negative to a positive value reflects relative changes in portal-to-arterial blood flow ratio.

The Biology of Metastasis to a Sanctuary Site

Metastasis to the brain is prevalent in solid tumors and lymphomas, and is associated with shortened survival. The brain is regarded as a sanctuary site for metastatic tumor cells where they exist partially protected from drugs by the blood-tumor barrier. Model systems for brain metastasis have been developed and are now yielding mechanistic insights into the roles of angiogenesis, energy metabolism, the Her-2 and Stat3 signaling pathways, and dormancy. Specific, new approaches to combat brain metastatic disease are needed.

Determination of the maturity and functionality of tumor vasculature by MRI: correlation between BOLD-MRI and DCE-MRI using P792 in experimental fibrosarcoma tumors

Using hypercapnia and carbogen as functional markers of vessel maturation and function, we compared blood oxygen level-dependent (BOLD) contrast with standard dynamic contrast-enhanced (DCE)-MRI quantitative parameters in murine fibrosarcoma. Our results show that there was no correlation between vessel maturity and contrast-agent uptake rate (K(in) (Trans)) or contrast agent efflux rate (k(ep)). In addition, DCE-MRI provided higher estimates of the fraction of functional tumor compared to BOLD-MRI. The two putative markers of regional vascular density, i.e., the magnitude of BOLD signal change during carbogen challenge (VF) and the fractional plasma volume found by DCE-MRI (V(p)), were only weakly correlated (r(2) = 0.02-0.14). Furthermore, VF showed no correlation with K(in) (Trans). A positive correlation was observed (r(2) = 0.75) between mean tumor VF and k(ep), but only when averaged over the whole tumor (which includes tumor regions completely unperfused by the gadolinium (Gd) contrast agent). This would merely reveal a relationship between perfusion status and the capacity to respond to carbogen breathing. In conclusion, characterizations of tumor microvasculature imaging using BOLD-MRI and DCE-MRI appear to be largely complementary, given the weak correlations between their corresponding derived parameters.

Quinoline, quinazoline and acridone alkaloids

This review covers the isolation, structure determination, synthesis and biological activity of quinoline, quinazoline and acridone alkaloids from plant, microbial and animal sources: 134 references are cited.

Halofuginone suppresses the lung metastasis of chemically induced hepatocellular carcinoma in rats through MMP inhibition

Halofuginone, an inhibitor of collagen synthesis, appears to be a promising antitumoral drug in preclinical studies. We used a relevant rat model of autochthonous, chemically induced, spontaneously metastasizing hepatocellular carcinoma (HCC) to test the efficacy of halofuginone on tumor progression and matrix metalloproteinase (MMP) expression. Following sequential administration of diethylnitrosamine and N-nitrosomorpholine for 14 weeks, all animals developed HCC and then received halofuginone or its solvent for 10 weeks. The final number of liver tumors was lower in the halofuginone group than in the solvent group (57.2 +/- 4.6 vs 68 +/- 5.0; P < .01). The percentage of the lung surface infiltrated by metastasis was much smaller in the halofuginone group (0.3 +/- 0.2%) than in the solvent group (13.5 +/- 10.1%; P < .02). MMP-9 activity was decreased in the halofuginone group by 89% and 63% in non-neoplastic parts of the liver and tumor, respectively. The percentage of active MMP-2 was reduced by 90% in non-neoplastic parts of the liver and by 61% in tumors. This was likely subsequent to a decreased expression of both MMP-14 and tissue inhibitor of matrix metalloproteinase-2, which are required for pro-MMP-2 activation. These results, obtained from a clinically relevant model, further suggest the potential benefit of halofuginone in HCC.

Phase I and pharmacokinetic study of halofuginone, an oral quinazolinone derivative in patients with advanced solid tumours

PURPOSE

Halofuginone (tempostatin) is a synthetic derivative of a quinazolinone alkaloid showing anti-angiogenic, anti-metastatic and anti-proliferative effects in preclinical studies. The objectives of this phase I study were to assess the dose-limiting toxicities (DLTs), to determine the maximum tolerated dose (MTD) and to study the pharmacokinetics (PKs) of halofuginone when administered once or twice daily orally to patients with advanced solid tumours.

METHODS

Patients were treated with escalating doses of halofuginone at doses ranging from 0.5 to 3.5 mg/day. For pharmacokinetic analysis plasma sampling was performed during the first and second course and assayed using a validated high-performance liquid chromatographic assay with mass spectrometric detection.

RESULTS

Twenty-four patients received a total of 106 courses. The 'acute' MTD was reached at 3.5 mg/day, with nausea, vomiting, and fatigue as DLT. The recommended dose for chronic administration was defined as 0.5mg/day with the requirement of 5HT3 antagonists to control nausea and vomiting considered as DLT. Several patients experienced bleeding complications on treatment with halofuginone in which a causal relationship could not be excluded. The PKs of halofuginone were linear over the dose range studied with a large interpatient variability.

CONCLUSIONS

In this study the DLT of halofuginone was nausea, vomiting, and fatigue. The recommended dose for phase II studies of halofuginone is 0.5mg administered orally, once daily.

Heparanase promotes growth, angiogenesis and survival of primary breast tumors

Despite great strides toward diagnosis and therapy, breast cancer remains a most threatening disease in its incidence, morbidity and mortality; therefore, additional knowledge regarding the molecular mechanisms contributing to breast cancer progression, as well as new targets for drug discovery are highly needed. Heparanase is the predominant enzyme involved in cleavage of heparan sulfate, the main polysaccharide component of the extracellular matrix. Experimental and clinical data indicate that heparanase plays important roles in cancer metastasis and angiogenesis. In breast carcinoma patients, heparanase expression correlates with the metastatic potential of the tumor. The present study was undertaken to investigate the role of heparanase in local growth and angiogenesis of primary breast tumors. MCF-7 breast carcinoma cells were stable transfected with the human heparanase (H-hpa) cDNA, or empty vector (mock), and injected into the mammary pad of nude mice. MRI was applied to monitor progression of tumor growth and angiogenesis. We demonstrate that tumors produced by cells overexpressing heparanase grew faster and were 7-fold larger than tumors produced by mock transfected cells. This enhanced growth was accompanied by increased tumor vascularization and a higher degree of vessel maturation. Histological examination ascribed the differences in tumor growth to heparanase-stimulated cell proliferation and survival. In-vitro experiments reinforced heparanase role as a survival factor under stress conditions. Moreover, H-hpa tumor cells infiltrate into the adjacent stroma, promoting formation of highly vascularized fibrous bands. Our results emphasize the significance and clarify the involvement of heparanase in primary breast cancer progression by generating a supportive microenvironment that promotes tumor growth, angiogenesis and survival.