Repeated Treatments with Ingenol Mebutate Prevents Progression of UV-Induced Photodamage in Hairless Mice

Skin cancer: understanding the journey of transformation from conventional to advanced treatment approaches

Skin cancer is a global threat to the healthcare system and is estimated to incline tremendously in the next 20 years, if not diagnosed at an early stage. Even though it is curable at an early stage, novel drug identification, clinical success, and drug resistance is another major challenge. To bridge the gap and bring effective treatment, it is important to understand the etiology of skin carcinoma, the mechanism of cell proliferation, factors affecting cell growth, and the mechanism of drug resistance. The current article focusses on understanding the structural diversity of skin cancers, treatments available till date including phytocompounds, chemotherapy, radiotherapy, photothermal therapy, surgery, combination therapy, molecular targets associated with cancer growth and metastasis, and special emphasis on nanotechnology-based approaches for downregulating the deleterious disease. A detailed analysis with respect to types of nanoparticles and their scope in overcoming multidrug resistance as well as associated clinical trials has been discussed.

Construction of a Secondary Enclosure for UVB Irradiation of Mice

UV irradiation is commonly used in murine models of skin cancers. Despite the popularity of using UVB rays to model photocarcinogenesis in animals, there is a lack of standardization in the secondary enclosures used to administer radiation. An appraisal of the literature also shows a general lack of details regarding the materials and procedures utilized in the fabrication of such enclosures. We present in this study a detailed overview of the construction of a UVB exposure chamber that successfully induces lesions in hairless mice. A standardized protocol for producing a UVB enclosure may reduce methodological variation in future studies seeking to investigate photocarcinogenesis in animals.

Mouse models for actinic keratoses

Actinic keratoses (AKs) represent a premalignant skin condition due to chronic sun damage that dramatically increases in prevalence in the aging population. Currently, animal models of AKs utilize photocarcinogenesis, chemical carcinogens, or targeted gene modulation, and each method possesses unique strengths and weaknesses. Models using photodamage most comprehensively describe methods for preferentially selecting AK lesions, while replicating the pathogenesis of AKs with greater fidelity than models utilizing other carcinogenic methods. The following review of current murine models of AKs will aid in the selection of mouse models appropriate for future in vivo studies to test the efficacy of novel therapeutic agents for the treatment of AKs.

Ingenol mebutate treatment in actinic keratosis - clinical effectiveness and potential side effects

Introduction

Actinic keratosis is a common skin disease that occurs in response to prolonged exposure to ultraviolet radiation. This problem affects up to 60% of the population over 40 years of age. Actinic keratosis is considered to be a precancerous lesion leading to squamous cell carcinoma (SCC). The new therapeutic option for the treatment of actinic keratosis is ingenol mebutate gel (0.015%, 0.05%).

Aim

Retrospective evaluation of response and potential side effects of ingenol mebutate treatment in clinical practice.

Material and methods

Eight patients with actinic keratosis lesions on the face or scalp self-applied a 0.015% gel for 3 consecutive days on the 25 cm² marked area. They were assessed at baseline and on day 4, 7, 14 and 57.

Results

All patients on day 57 presented a complete absence of AK lesions in the area of ingenol mebutate application. No adverse events were observed.

Conclusions

Our study shows that ingenol mebutate is highly efficacious field treatment for actinic keratosis.

Mediators of Inflammation in Topical Therapy of Skin Cancers

Taking into consideration that the immune system plays a very important role in the development of melanoma and non-melanoma skin cancers, which have a high prevalence in immunosuppressed patients and after prolonged ultraviolet radiation, the interest in developing novel therapies, in particular targeting the inflammation in cancer, has increased in the past years. The latest data suggest that therapies such as imiquimod (IMQ), ingenol mebutate (IM), 5-fluorouracil (5-FU), retinoids, and nonsteroidal anti-inflammatory drugs (NSAIDs) have been used with success in the topical treatment of some cancers. Herein, we review the topical treatment targeting the inflammation in skin cancer and the mechanisms involved in these processes. Currently, various associations have shown a superior success rate than monotherapy, such as systemic acitretin and topical IMQ, topical 5-FU with tretinoin cream, or IMQ with checkpoint inhibitor cytotoxic T lymphocyte antigen 4. Novel therapies targeting Toll-like receptor-7 (TLR-7) with higher selectivity than IMQ are also of great interest.

A Prospective Pilot Clinical Trial to Evaluate the Efficacy and Safety of Topical Therapy with Ingenol Mebutate Gel 0.015% for Actinic Keratosis on an Expanded Area of the Chest

BACKGROUND: Ingenol mebutate gel 0.05% once daily for two consecutive days provides high clearance rates for actinic keratosis on a 25cm² area of the chest. However, it may cause intense local skin responses. OBJECTIVE: The objective of this study was to determine whether a lower dose of ingenol mebutate gel 0.015% could clear actinic keratosis on the chest with acceptable tolerability and a possible beneficial effect on photodamage and cosmesis. DESIGN: This was a noncomparative, open-label study (NCT02446223). PARTICIPANTS: In total, 21 subjects were enrolled, and 20 completed the study. MEASUREMENTS: ingenol mebutate gel 0.015% was applied once daily for three consecutive days to a contiguous area of the chest less than 100cm² containing four or more actinic keratoses. RESULTS: the actinic keratosis lesion count decreased by an average of 76 percent compared with baseline. signs of photoaging were reduced significantly at the end of the study, with greater than 60 percent of the subjects reporting moderate or complete satisfaction with skin improvement. Local skin responses generally resolved within two weeks of treatment. there were no adverse reactions. LIMITATIONS: this was a noncomparative, open-label study that evaluated a relatively small number of subjects. CONCLUSION: ingenol mebutate gel 0.015% applied to a less than 100cm² area of the chest once daily for three consecutive days reduced the actinic keratosis count and significantly improved signs of photoaging with high patient satisfaction and good tolerability.