pep005 and Carcinogenesis

BACKGROUND A recent focus in skin cancer prevention intervenes though modulating molecular links between inflammation and cell growth signaling, such as NF-κB. This study elucidates the effect of a non-tumor promoting phorbol ester, ingenol-3-angelate (I3A), on the growth of human melanoma cells and on the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation and 7,12-Dimethylbenz(a)anthracene (DMBA)-induced skin carcinoma in mice. MATERIAL AND METHODS Cell viability was assessed by MTT assay, cell proliferation by clonogenic assay, apoptosis and cell cycle arrest was analyzed by flow cytometry, protein expression was studied by IHC and Western blotting, and gene expression by qPCR. RESULTS I3A suppressed the survival and proliferation of human melanoma cells with estimated IC50 values around 38 and 46 μM for A2058 and HT144 cell, respectively. I3A activated the protein levels of PKCδ and PKCε, which induced apoptosis by activating caspase-9 and caspace-3 followed by lowering of mitochondrial membrane potential and enhancing DNA fragmentation. I3A induced G1 phase cell cycle arrest as well as G2/M phase arrest in both cell lines. I3A inhibited the levels of NFκB p65 protein as well as phosphorylation of p65 and its nuclear translocation. I3A suppressed the gene expression of NF-κB, COX-2 and iNOS. I3A inhibited TPA-induced inflammation and epidermal hyperplasia in female ICR mice by downregulating NF-κB and iNOS. I3A suppressed the growth of skin tumor in DMBA-induced mice in dose-dependent manner. CONCLUSIONS The mechanism of I3A induces apoptosis in human melanoma cells and suppresses skin inflammation and carcinoma via downregulation of NF-κB-iNOS-COX-2 signaling.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Apoptosis; Apoptosis Regulatory Proteins; Carcinogenesis; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cyclooxygenase 2; Diterpenes; Down-Regulation; Epidermis; Female; Hyperplasia; Inflammation; Melanoma; Mice, Inbred ICR; NF-kappa B; Signal Transduction; Skin Neoplasms; Tetradecanoylphorbol Acetate

We present the case of a 73-year-old male patient who had received a first renal transplant at 36 years and a second one at the age of 55 years. He is currently under immunosuppression with everolimus 2.5 mg/day and prednisone 5 mg/day. The patient presented with multiple actinic keratoses on both cheeks and the forehead and received treatment by ingenol mebutate 150 µg/g gel daily on 3 consecutive days on his right cheek and methyl aminolevulinate (MAL) photodynamic therapy activated by daylight (MAL-dPDT) on the forehead and the left cheek. MAL-dPDT treatment proved a feasible, repeatable, physician-directed method of treating field cancerization with limited morbidity for a period of 6 days. Treatment with ingenol mebutate gel was a feasible, possibly self-directed method of treating field cancerization with limited morbidity for 10 days in this immunosuppressed patient. Both treatments showed similar efficacy. At the time of treatment, the MAL daylight PDT ran at 3 times the cost of ingenol mebutate gel.

Topics: Aged; Aminolevulinic Acid; Antineoplastic Agents; Carcinogenesis; Carcinoma, Basal Cell; Carcinoma, Squamous Cell; Diterpenes; Face; Humans; Keratosis, Actinic; Kidney Transplantation; Male; Photochemotherapy; Photosensitizing Agents; Skin Neoplasms; Transplant Recipients

Patients suffering from chronic lymphocytic leukemia often develop actinic keratosis (AK) and squamous cell carcinoma in sun-exposed areas. In these particular patients, who have a suboptimal immune function, AK treatment can be particularly challenging. We report the case of a patient who failed to respond to most AK treatments, including 5-FU, imiquimod and photodynamic therapy, but responded to ingenol mebutate. We started with 3 applications of 150 μg/g (registered treatment of the scalp) and also 2 applications of 500 μg/g (registered in for trunk and extremities). Both treatments were well tolerated, but only the latter led to significant clinical success. This suggests that 500 μg/g of ingenol mebutate may represent an interesting therapeutic option in patients with mild immunosuppression.

Topics: Aged; Antineoplastic Agents; Carcinogenesis; Carcinoma, Basal Cell; Carcinoma, Squamous Cell; Diterpenes; Humans; Keratosis, Actinic; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Scalp; Skin Neoplasms

The incidence of squamous cell carcinomas (SCC) is increasing, and effective chemopreventative strategies are needed. We hypothesized that repeated treatments with ingenol mebutate (IngMeb) would postpone development of SCC in hairless mice, and that application of a corticosteroid would reduce IngMeb-induced local skin responses (LSRs) without affecting tumor postponement.. Hairless mice (n=150; 6 groups á 25 mice) were irradiated with solar simulated ultraviolet radiation (UVR) until SCC developed. During UV-irradiation and before tumor development, five single treatments (Tx) with IngMeb were given at four-week intervals (days 21, 49, 77, 105, 133). Clobetasol propionate (CP) was applied once daily for 5days prior to IngMeb, as well as 6h and 1day post treatment. Tumor formation was evaluated weekly for 52weeks. LSR (scale 0-24) were assessed at baseline, 1h, 6h, 1-, 2-, 3-, 4-, 5-, 6-, and 7days after each IngMeb treatment.. IngMeb significantly delayed tumor development compared to UVR alone (UVR day 168 vs. UVR+IngMeb day 189; p=0.025). LSR included erythema, flaking, crusting, bleeding, vesiculation, and ulceration. The composite LSR-scores were of moderate intensity in non-UV irradiated skin (max LSR IngMeb Tx 1-5: 1.5-2.5) and more pronounced in photodamaged skin (max LSR Tx 5; IngMeb 1.5 vs. UVR+IngMeb 1.8; p<0.001). LSR intensity correlated with tumor development by means of greater composite LSR-score resulted in longer tumor-free survival (r(2)=0.257, p<0.001). Contrary to our hypothesis, concurrent CP increased LSR (max LSR Tx 1-5: UVR+CP+IngMeb 3.2-4.9 vs. UVR+IngMeb 1.3-2.2, p<0.001) and postponed tumor development compared to IngMeb alone (UVR+CP+IngMeb day 217 vs. UVR+IngMeb day 189, p<0.001).. Repeated field-directed treatments with IngMeb delay development of UV-induced SCC in hairless mice, and increased IngMeb induced LSRs correlated with improved clinical outcomes. The findings highlight the potential of IngMeb as a prophylactic remedy for SCC in humans.

Topics: Animals; Carcinogenesis; Carcinoma, Squamous Cell; Diterpenes; Female; Mice; Mice, Hairless; Pigmentation; Skin; Skin Neoplasms; Ultraviolet Rays