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ABSTRACT: Ingenol mebutate has recently been approved by the Federal Drug Administration (USA) as a topical treatment for actinic keratoses. Herein, we describe the efficacy of ingenol mebutate for the topical treatment of squamous cell carcinoma (SCC) using a wild-type mouse model (SKH1) and the UV-induced mouse SCC cell line, T7. Daily treatment for 2 days with 0.25 % ingenol mebutate gel produced a cure rate of 70 %, with 0 % for placebo gel. Electron microscopy revealed swelling of cancer cell mitochondria within 1 h, with disruption of the inner mitochondrial membranes evident at 6 h post treatment. Primary necrosis of cancer cells was clearly evident by 24 h. Treatment was associated with local haemorrhage and a prodigious neutrophil infiltrate, with anti-T7 antibodies also detected. This is the first report of the successful treatment of SCC tumours with ingenol mebutate gel in wild-type mice, and supports the view that ingenol mebutate induces primary necrosis and activates the immune system.
Archives for Dermatological Research 08/2012; · 2.28 Impact Factor
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ABSTRACT: Skin cancer is the most prevalent cancer worldwide and is primarily caused by chronic UV exposure. Here, we describe the topical field-directed treatment of SKH1/hr mice with UVB-damaged skin with ingenol mebutate, a new topical drug shown to be effective for the treatment of actinic keratosis (AK). Application of 0.05% ingenol mebutate gel to photo-damaged skin resulted in a ≈70% reduction in the number of skin lesions that subsequently emerged compared with placebo treatment. Ingenol mebutate treatment also reduced the number of mutant p53 keratinocyte patches by ≈70%. The treatment resulted in epidermal cell death, acute inflammation, recruitment of neutrophils, hemorrhage, and eschar formation, all of which resolved over several weeks. Ingenol mebutate field-directed treatment might thus find utility in the removal of subclinical precancerous cells from UV-damaged skin. Field-directed treatment may be particularly suitable for patients who have AKs surrounded by UV-damaged skin.
Journal of Investigative Dermatology 12/2011; 132(4):1263-71. · 6.31 Impact Factor
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ABSTRACT: To evaluate the safety of two applications of PEP005 (ingenol mebutate) gel in superficial basal cell carcinoma. Efficacy was a secondary end-point.
Randomized, vehicle-controlled, phase IIa study conducted at eight private dermatology clinics in Australia. A total of 60 patients with histologically confirmed superficial basal cell carcinoma (lesion size, 4-15 mm) were randomized to treatment on days 1 and 2 (Arm A) or days 1 and 8 (Arm B) and, within each arm, to ingenol mebutate gel, 0.0025%, 0.01% or 0.05%, or vehicle gel. The main outcome measures were the incidence and severity of adverse events and local skin responses in Arms A and B; lesion clearance at day 85 was a secondary measure.
The incidence of adverse events was low. One patient treated with ingenol mebutate gel, 0.05% in Arm A experienced severe flaking/scaling/dryness extending beyond the application site. Non-severe, potentially treatment-related events included erythema extending beyond the application site, application-site pain and headache in two patients each. Six patients in Arm A had one or more severe local skin responses. Efficacy appeared to be dose-related and there was a trend towards higher clinical and histological lesion clearance rates in Arm A compared with Arm B. Histological clearance occurred in five of eight patients (63%) randomized to ingenol mebutate gel, 0.05% in Arm A.
Two applications of ingenol mebutate gel, 0.05%, are safe and have efficacy in patients with superficial basal cell carcinoma.
Australasian Journal of Dermatology 05/2010; 51(2):99-105. · 1.00 Impact Factor
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ABSTRACT: Ingenol-3-angelate is a new local chemotherapeutic agent in clinical trails that induces primary necrosis of tumour cells and transient local inflammation. Here we show that cure of subcutaneous tumours with ingenol-3-angelate (PEP005) resulted in the generation of anti-cancer CD8 T cells that could regress metastases. Furthermore, PEP005-mediated cure synergized with several CD8 T cell-based immunotherapies to regress further distant metastases. PEP005 was shown to have adjuvant properties, being able to upregulate CD80 and CD86 expression on dendritic cells in vivo, and to promote CD8 T cell induction when co-delivered with a protein antigen. PEP005 thus emerges as a unique local chemotherapeutic immunostimulatory debulking agent that could be used in conjunction with immunotherapies to promote regression of metastases.
Vaccine 06/2009; 27(23):3053-62. · 3.77 Impact Factor
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ABSTRACT: The sap of the plant Euphorbia peplus is a traditional remedy for skin conditions, including actinic keratosis. The active constituent of the sap is ingenol mebutate (ingenol-3-angelate), formerly known as PEP005. This randomized, double-blind, vehicle-controlled, phase IIa study investigated the safety (and secondarily the efficacy) of two applications of ingenol mebutate gel in 58 patients with biopsy-confirmed actinic keratosis. Five preselected lesions were treated with ingenol mebutate gel, 0.0025%, 0.01% or 0.05%, or vehicle gel, on days 1 and 2 (Arm A) or days 1 and 8 (Arm B). There were no significant differences in tolerability or efficacy between Arms A and B. Treatment was well tolerated. The most common local skin responses were dose-related erythema, flaking/scaling/dryness and scabbing/crusting. Efficacy was greatest with ingenol mebutate gel, 0.05%, which resulted in complete clinical clearance of 71% of treated lesions (P < 0.0001 vs vehicle gel). In addition, 67% of patients treated with ingenol mebutate gel, 0.05% had clinical clearance of at least four of five treated lesions (P = 0.0185 vs vehicle gel). Ingenol mebutate gel is being developed as a short-course topical therapy for actinic keratosis and non-melanoma skin cancer.
Australasian Journal of Dermatology 02/2009; 50(1):16-22. · 1.00 Impact Factor
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Maria Serova,
Aïda Ghoul,
Karim A Benhadji,
Sandrine Faivre,
Christophe Le Tourneau,
Esteban Cvitkovic,
Francois Lokiec,
Janet Lord, Steven M Ogbourne,
Fabien Calvo,
Eric Raymond
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ABSTRACT: PEP005 (ingenol-3-angelate) is a novel anticancer agent extracted from Euphorbia peplus that was previously shown to modulate protein kinase C (PKC), resulting in antiproliferative and proapoptotic effects in several human cancer cell lines. In Colo205 colon cancer cells, exposure to PEP005 induced a time- and concentration-dependent decrease of cells in S phase of cell cycle and apoptosis. In Colo205 cells exposed to PEP005, a variety of signaling pathways were activated as shown by increased phosphorylation of PKCdelta, Raf1, extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase (MAPK), c-Jun NH(2)-terminal kinase, p38 MAPK, and PTEN. PEP005-induced activation of PKCdelta was associated with its translocation from the cytosol to the nucleus and other cellular membranes. Interestingly, PEP005 treatment also resulted in reduced expression of PKCalpha and reduced levels of phosphorylated active form of AKT/protein kinase B. These data suggest that PEP005-induced activation of PKCdelta and reduced expression of PKCalpha resulted in apoptosis by mechanisms mediated by activation of Ras/Raf/MAPK and inhibition of the phosphatidylinositol 3-kinase/AKT signaling pathways. This study supports ongoing efforts targeting PKC isoforms in cancer therapy with PEP005 alone and in combination with other cytotoxic agents.
Molecular Cancer Therapeutics 05/2008; 7(4):915-22. · 5.23 Impact Factor
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ABSTRACT: The sap of Euphorbia peplus, commonly know as 'petty spurge', 'radium weed' or 'milkweed' has been used for centuries as a traditional treatment for skin conditions, including warts, corns and cancers of the skin. Documentation of its use by medical professionals to treat basal cell carcinoma (BCC) dates from the early 19 century. Individuals who participated in a 1988 survey of home treatments for cancer indicated the sap of E. peplus was an effective cure for actinic lesions leading the investigators to suggest that this potential utility should be further explored in controlled clinical trials. The fractionation of the sap E. peplus using solvents of varying polarity yielded several macrocyclic diterpenes, many of which were found to have cytotoxic activity or the ability to influence cellular differentiation. Ultimately, ingenol 3-angelate (I3A) of PEP005, emerged as a promising potential new anti-cancer treatment. Here we report the proceedings from the First International Conference on PEP005, covering the exciting potential of PEP005 as the therapeutic agent for the treatment of skin cancer, leukemia and bladder cancer.
Anti-Cancer Drugs 04/2007; 18(3):357-62. · 2.41 Impact Factor
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Jodie M Challacombe,
Andreas Suhrbier,
Peter G Parsons,
Brad Jones,
Peter Hampson,
Dean Kavanagh,
G Ed Rainger,
Melanie Morris,
Janet M Lord,
Thuy T T Le,
Diem Hoang-Le, Steven M Ogbourne
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ABSTRACT: Harnessing neutrophils for the eradication of cancer cells remains an attractive but still controversial notion. In this study, we provide evidence that neutrophils are required to prevent relapse of skin tumors following topical treatment with a new anticancer agent, ingenol-3-angelate (PEP005). Topical PEP005 treatment induces primary necrosis of tumor cells, potently activates protein kinase C, and was associated with an acute T cell-independent inflammatory response characterized by a pronounced neutrophil infiltrate. In Foxn1(nu) mice depleted of neutrophils and in CD18-deficient mice (in which neutrophil extravasation is severely impaired) PEP005 treatment was associated with a >70% increase in tumor relapse rates. NK cell or monocyte/macrophage deficiency had no effect on relapse rates. Both in vitro and in mice, PEP005 induced MIP-2/IL-8, TNF-alpha, and IL-1beta, all mediators of neutrophil recruitment and activation. In vitro, PEP005 activated human endothelial cells resulting in neutrophil adhesion and also induced human neutrophils to generate tumoricidal-reactive oxygen intermediates. Treatment of tumors with PEP005 significantly elevated the level of anticancer Abs, which were able to promote neutrophil-mediated Ab-dependent cellular cytotoxicity (ADCC) in vitro. PEP005 treatment of tumors grown in SCID mice was also associated with >70% increase in tumor relapse rates. Taken together, these data suggest a central role for neutrophil-mediated ADCC in preventing relapse. PEP005-mediated cure of tumors therefore appears to involve initial chemoablation followed by a neutrophil-dependent ADCC-mediated eradication of residual disease, illustrating that neutrophils can be induced to mediate important anticancer activity with specific chemotherapeutic agents.
The Journal of Immunology 01/2007; 177(11):8123-32. · 5.79 Impact Factor
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ABSTRACT: The diterpene ester PEP005 is a novel anticancer agent that activates protein kinase C (PKC) and induces cell death in melanoma at high doses. We now describe the in vitro cytostatic effects of PEP005 and the diterpene ester phorbol 12-myristate 13-acetate, observed in 20% of human melanoma cell lines. Primary cultures of normal human neonatal fibroblasts were resistant to growth arrest, indicating a potential for tumor selectivity. Sensitive cell lines were induced to senesce and exhibited a G(1) and G(2)-M arrest. There was sustained expression of p21(WAF1/CIP1), irreversible dephosphorylation of the retinoblastoma protein, and transcriptional silencing of E2F-responsive genes in sensitive cell lines. Activation of mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase (MEK) 1/2 by PKC was required for diterpene ester-induced senescence. Expression profiling revealed that the MAP kinase inhibitor HREV107 was expressed at a higher transcript level in resistant compared with sensitive cell lines. We propose that activation of PKC overstimulates the RAS/RAF/MEK/ERK pathway, resulting in molecular changes leading to the senescent phenotype.
Cancer Research 11/2006; 66(20):10083-91. · 7.86 Impact Factor
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Steven M Ogbourne,
Andreas Suhrbier,
Brad Jones,
Sarah-Jane Cozzi,
Glen M Boyle,
Melanie Morris,
Devi McAlpine,
Jenny Johns,
Tania M Scott,
Kirsty P Sutherland,
Joy M Gardner,
Thuy T T Le,
Aleksandra Lenarczyk,
James H Aylward,
Peter G Parsons
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ABSTRACT: Options for skin cancer treatment currently include surgery, radiotherapy, topical chemotherapy, cryosurgery, curettage, and electrodessication. Although effective, surgery is costly and unsuitable for certain patients. Radiotherapy can leave a poor cosmetic effect, and current chemotherapy is limited by low cure rates and extended treatment schedules. Here, we describe the preclinical activity of a novel topical chemotherapeutic agent for the treatment of skin cancer, 3-ingenyl angelate (PEP005), a hydrophobic diterpene ester isolated from the plant Euphorbia peplus. Three daily topical applications of 42 nmol (18 micro g) of PEP005 cured a series of s.c. mouse tumors (B16 melanoma, LK2 UV-induced squamous cell carcinoma, and Lewis lung carcinoma; n = >14 tumors/group) and human tumors (DO4 melanoma, HeLa cervical carcinoma, and PC3 and DU145 prostate carcinoma; n = >4 tumors/group) previously established (5-10 mm(3)) on C57BL/6 or Foxn1(nu) mice. The treatment produced a mild, short-term erythema and eschar formation but, ultimately, resulted in excellent skin cosmesis. The LD(90) for PEP005 for a panel of tumor cell lines was 180-220 micro M. Electron microscopy showed that treatment with PEP005 both in vitro (230 micro M) and in vivo (42 nmol) rapidly caused swelling of mitochondria and cell death by primary necrosis. (51)Cr release, uptake of propidium iodide, and staining with the mitochondria dye JC1, revealed that PEP005 (230 micro M) treatment of tumor cells in vitro resulted in a rapid plasma membrane perturbation and loss of mitochondrial membrane potential. PEP005 thus emerges as a new topical anti-skin cancer agent that has a novel mode of action involving plasma membrane and mitochondrial disruption and primary necrosis, ultimately resulting in an excellent cosmetic outcome.
Cancer Research 05/2004; 64(8):2833-9. · 7.86 Impact Factor
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ABSTRACT: Plasminogen activator inhibitor-2 (PAI-2) is well documented as an inhibitor of the extracellular serine proteinase urokinase-type plasminogen activator (uPA) and is expressed in activated monocytes and macrophages, differentiating keratinocytes, and many tumors. Here we show that PAI-2 has a novel intracellular function as a retinoblastoma protein (Rb)-binding protein. PAI-2 colocalized with Rb in the nucleus and inhibited the turnover of Rb, which led to increases in Rb protein levels and Rb-mediated activities. Although PAI-2 contains an LXCXE motif, Rb binding was primarily mediated by the C-D interhelical region of PAI-2, which was found to bind to the C pocket of Rb. The C-D interhelical region of PAI-2 contained a novel Rb-binding motif, termed the PENF homology motif, which is shared by many cellular and viral Rb-binding proteins. PAI-2 expression also protected Rb from the accelerated degradation mediated by human papillomavirus (HPV) E7, leading to recovery of Rb and inhibition of E6/E7 mRNA expression. Protection of Rb by PAI-2 begins to explain many of the diverse, uPA-independent phenotypes conferred by PAI-2 expression. These results indicate that PAI-2 may enhance Rb's tumor suppressor activity and suggest a potential therapeutic role for PAI-2 against HPV-transformed lesions.
Molecular and Cellular Biology 10/2003; 23(18):6520-32. · 5.53 Impact Factor
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ABSTRACT: Many serine proteases play important regulatory roles in complex biological systems, but only a few have been linked directly with capillary morphogenesis and angiogenesis. Here we provide evidence that serine protease activities, independent of the plasminogen activation cascade, are required for microvascular endothelial cell reorganization and capillary morphogenesis in vitro. A homology cloning approach targeting conserved motifs present in all serine proteases, was used to identify candidate serine proteases involved in these processes, and revealed 5 genes (acrosin, testisin, neurosin, PSP and neurotrypsin), none of which had been associated previously with expression in endothelial cells. A subsequent gene-specific RT-PCR screen for 22 serine proteases confirmed expression of these 5 genes and identified 7 additional serine protease genes expressed by human endothelial cells, urokinase-type plasminogen activator, protein C, TMPRSS2, hepsin, matriptase/MT-SP1, dipeptidylpeptidase IV, and seprase. Differences in serine protease gene expression between microvascular and human umbilical vein endothelial cells (HUVECs) were identified and several serine protease genes were found to be regulated by the nature of the substratum, ie. artificial basement membrane or fibrillar type I collagen. mRNA transcripts of several serine protease genes were associated with blood vessels in vivo by in situ hybridization of human tissue specimens. These data suggest a potential role for serine proteases, not previously associated with endothelium, in vascular function and angiogenesis.
Thrombosis and Haemostasis 04/2003; 89(3):561-72. · 5.04 Impact Factor
