Antiproliferative activity of PEP005, a novel ingenol angelate that modulates PKC functions, alone and in combination with cytotoxic agents in human colon cancer cells

PEP005 is a novel ingenol angelate that modulates protein kinases C (PKC) functions by activating PKCδ and inhibiting PKCα. This study assessed the antiproliferative effects of PEP005 alone and in combination with several other anticancer agents in a panel of 10 human cancer cell lines characterised for expression of several PKC isoforms. PEP005 displayed antiproliferative effects at clinically relevant concentrations with a unique cytotoxicity profile that differs from that of most other investigated cytotoxic agents, including staurosporine. In a subset of colon cancer cells, the IC50 of PEP005 ranged from 0.01–140 μM. The antiproliferative effects of PEP005 were shown to be concentration- and time-dependent. In Colo205 cells, apoptosis induction was observed at concentrations ranging from 0.03 to 3 μM. Exposure to PEP005 also induced accumulation of cells in the G1 phase of the cell cycle. In addition, PEP005 increased the phosphorylation of PKCδ and p38. In Colo205 cells, combinations of PEP005 with several cytotoxic agents including oxaliplatin, SN38, 5FU, gemcitabine, doxorubicin, vinorelbine, and docetaxel yielded sequence-dependent antiproliferative effects. Cell cycle blockage induced by PEP005 in late G1 lasted for up to 24 h and therefore a 24 h lag-time between PEP005 and subsequent exposure to cytotoxics was required to optimise PEP005 combinations with several anticancer agents. These data support further evaluation of PEP005 as an anticancer agent and may help to optimise clinical trials with PEP005-based combinations in patients with solid tumours

Glyphosate: Environmental contamination, toxicity and potential risks to human health via food contamination

Glyphosate has been the most widely used herbicide during the past three decades. The US Environmental Protection Agency (EPA) classifies glyphosate as ‘practically non-toxic and not an irritant’ under the acute toxicity classification system. This classification is based primarily on toxicity data and due to its unique mode of action via a biochemical pathway that only exists in a small number of organisms that utilise the shikimic acid pathway to produce amino acids, most of which are green plants. This classification is supported by the majority of scientific literature on the toxic effects of glyphosate. However, in 2005, the Food and Agriculture Organisation (FAO) reported that glyphosate and its major metabolite, aminomethylphosphonic acid (AMPA), are of potential toxicological concern, mainly as a result of accumulation of residues in the food chain. The FAO further states that the dietary risk of glyphosate and AMPA is unlikely if the maximum daily intake of 1 mg kg−1body weight (bw) is not exceeded. Research has now established that glyphosate can persist in the environment, and therefore, assessments of the health risks associated with glyphosate are more complicated than suggested by acute toxicity data that relate primarily to accidental high-rate exposure. We have used recent literature to assess the possible risks associated with the presence of glyphosate residues in food and the environment. © 2016, Springer-Verlag Berlin Heidelberg

Tattoo removal with ingenol mebutate

Sarah-Jane Cozzi,1 Thuy T Le,1 Steven M Ogbourne,2 Cini James,1 Andreas Suhrbier1 1Inflammation Biology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, 2Genecology Research Center, Faculty of Science, Health, Engineering and Education, University of the Sunshine Coast, Maroochydore DC, QLD, Australia Abstract: An increasing number of people are getting tattoos; however, many regret the decision and seek their removal. Lasers are currently the most commonly used method for tattoo removal; however, treatment can be lengthy, costly, and sometimes ineffective, especially for certain colors. Ingenol mebutate is a licensed topical treatment for actinic keratoses. Here, we demonstrate that two applications of 0.1% ingenol mebutate can efficiently and consistently remove 2-week-old tattoos from SKH/hr hairless mice. Treatment was associated with relocation of tattoo microspheres from the dermis into the posttreatment eschar. The skin lesion resolved about 20 days after treatment initiation, with some cicatrix formation evident. The implications for using ingenol mebutate for tattoo removal in humans are discussed. Keywords: tattoo, ingenol mebutate, mouse&nbsp

Effects of protein kinase C modulation by PEP005, a novel ingenol angelate, on mitogen-activated protein kinase and phosphatidylinositol 3-kinase signaling in cancer cells

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 PKCδ, Raf1, extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase (MAPK), c-Jun NH2-terminal kinase, p38 MAPK, and PTEN. PEP005-induced activation of PKCδ was associated with its translocation from the cytosol to the nucleus and other cellular membranes. Interestingly, PEP005 treatment also resulted in reduced expression of PKCα and reduced levels of phosphorylated active form of AKT/protein kinase B. These data suggest that PEP005-induced activation of PKCδ and reduced expression of PKCα 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

Neutrophils are a key component of the antitumor efficacy of topical chemotherapy with ingenol-3-angelate

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 Foxn1nu 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-α, and IL-1, 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

Short-term application of mulch, roundup and organic herbicides did not affect soil microbial biomass or bacterial and fungal diversity

Application of synthetic herbicides is currently the most widely used and cost-effective methods to assist with revegetation programs. However, the effects of short-term application of herbicides such as Roundup®, acetic acid, BioWeed™ and Slasher® as compared with mulch, on soil microbial biomass and microbial diversity remain unknown. This study examined the effects of short-term herbicide application on soil microbial biomass, C:N ratio, and fungal and bacterial communities at months 2 and 8 following initiation of treatment application. No effects of treatments on soil pH, C:N and microbial biomass were found. No segregation among treatments in the community structure of bacteria and fungi was observed. However, the fungal phylum Basiodiomycota had one unidentified class, which was only found in the mulch treatment, suggesting the C quality in the mulch treatment may differ compared with the other treatments. The dry and hot conditions experienced throughout the study period may have resulted in fast degradation of the herbicides and may have minimised the impacts of the herbicides on microbial diversity and community structure. Given that the research was undertaken at a single site and over only a short time frame, the results should be extrapolated with caution. Herbicides may have greater impact with long-term use. Future research will need to assess the revegetation success of each treatment and determine if the observed change in Basidiomycota profile and C quality identified in this study becomes significant over the long-term. We hypothesise that mulching may be a preferred treatment to facilitate weed control in riparian zone revegetation. © 2019 Elsevier Lt