Fergal J. Moloney

DNAzyme targeting c-jun suppresses skin cancer growth

Catalytic DNA molecules that target the transcription factor c-jun inhibit skin cancer growth in mice. Getting Under Cancer’s Skin Summer brings to mind barbecues, baseball, and trips to the local pool. Yet, outdoor fun can be hazardous to one’s health—too much sun exposure can increase the risk of developing skin cancer. Indeed, one in three cancers worldwide is skin-related, and currently available treatments may induce scarring or other toxicities. Cai et al. now report that the DNAzyme Dz13—which targets an mRNA that encodes a cancer-associated transcription factor, c-Jun—inhibits the growth of two common types of skin cancers: basal cell and squamous cell carcinomas. DNAzymes are single-stranded, all-DNA, catalytic molecules that specifically bind and cleave their target RNAs. The authors examined the effects of Dz13, which destroys c-jun mRNA, on animal models of skin cancer. Dz13 inhibited tumor growth, blocked neovascularization, and prevented metastasis in mouse models of skin cancer—effects that were mediated, in part, through the induction of antitumor immunity. Minimal toxicity was observed in Dz13-treated cynomolgus monkeys, minipigs, and rodents, and there were no off-target effects in more than 70 in vitro bioassays. Thus, Dz13 may prove to be a safe, effective therapy for skin cancer. Nonetheless, one is advised to pack the sun block in preparation for extra innings—or a fifth set. Worldwide, one in three cancers is skin-related, with increasing incidence in many populations. Here, we demonstrate the capacity of a DNAzyme-targeting c-jun mRNA, Dz13, to inhibit growth of two common skin cancer types—basal cell and squamous cell carcinomas—in a therapeutic setting with established tumors. Dz13 inhibited tumor growth in both immunodeficient and immunocompetent syngeneic mice and reduced lung nodule formation in a model of metastasis. In addition, Dz13 suppressed neovascularization in tumor-bearing mice and zebrafish and increased apoptosis of tumor cells. Dz13 inhibition of tumor growth, which required an intact catalytic domain, was due in part to the induction of tumor immunity. In a series of good laboratory practice–compliant toxicology studies in cynomolgus monkeys, minipigs, and rodents, the DNAzyme was found to be safe and well tolerated. It also did not interfere in more than 70 physiologically relevant in vitro bioassays, suggesting a reduced propensity for off-target effects. If these findings hold true in clinical trials, Dz13 may provide a safe, effective therapy for human skin cancer.

Sunscreens: safety, efficacy and appropriate use.

Promoting sunscreen use is an integral part of prevention programmes aimed at reducing ultraviolet (UV) radiation-induced skin damage and skin cancers. Protection against both UVB and UVA radiation is advocated. Most sunscreens combine chemical UV absorbing sunscreens and physical inorganic sunscreens, which reflect UV, to provide broad-spectrum protection. Newer triazole and camphor-derivative based sunscreens, also provide broad-spectrum protection and are more cosmetically acceptable than many traditional agents. Currently licensed sunscreen ingredients in common use rarely cause allergic or photoallergic reactions. Vitamin D levels are not significantly affected by regular use of a sunscreen. Sunscreen use reduces both the development of precancerous solar keratosis and the recurrence of squamous cell carcinomas. Sunscreen use early in life may be important in prevention of basal cell carcinomas. Increased melanoma risk is influenced by the behaviour patterns of regular sunscreen users, as opposed to any direct effect of sunscreens. Sun protection factor (SPF) is affected by application density, water resistance and other factors. An adequate SPF for an individual should be balanced to skin phenotype and exposure habits. The correct use of sunscreens should be combined with the avoidance of midday sun and the wearing of protective clothing and glasses, as part of an overall sun protection regimen.

Improving Management and Patient Care in Lentigo Maligna by Mapping With In Vivo Confocal Microscopy

IMPORTANCE Lentigo maligna (LM) is a clinical, pathologic, and therapeutic challenge with a higher risk of local recurrence than other types of melanoma correctly treated and also carries the cosmetically sensitive localization of head and neck. OBJECTIVE To determine whether in vivo reflectance confocal microscopy (RCM) mapping of difficult LM cases might alter patient care and management. DESIGN Analysis of LM and LM melanoma (LMM) in a series of patients with large facial lesions requiring complex reconstructive surgery and/or recurrent or poorly delineated lesions at any body sites were investigated. SETTINGS Two tertiary referral melanoma centers in Sydney, Australia. PARTICIPANTS Thirty-seven patients with LM (including 5 with LMM) were mapped with RCM. Fifteen patients had a recurrent LM, including 9 with multiple prior recurrences. The LM was classified amelanotic in 10 patients, lightly pigmented in 9, and partially pigmented in 18. INTERVENTIONS The RCM images were obtained in 4 radial directions (allowing for anatomic barriers) for LM margin delineation using an RCM LM score previously described by our research team. MAIN OUTCOME MEASURES Differences in the margin of LM as determined by RCM vs dermoscopy vs histopathologic analysis. RESULTS Seventeen of 29 patients (59%) with dermoscopically visible lesions had subclinical (RCM-identified) disease evident more than 5 mm beyond the dermoscopy margin (ie, beyond the excision margin recommended in published guidelines). The RCM mapping changed the management in 27 patients (73%): 11 patients had a major change in their surgical procedure, and 16 were offered radiotherapy or imiquimod treatment as a consequence of the RCM findings. Treatment was surgical in 17 of 37 patients. Surgical excision margins (based on the RCM mapping) were histopathologically involved in only 2 patients, each of whom had an LM lesion larger than 6 cm. CONCLUSIONS AND RELEVANCE In vivo RCM can provide valuable information facilitating optimal patient care management.

Oral Nicotinamide Reduces Actinic Keratoses in Phase II Double-Blinded Randomized Controlled Trials

TO THE EDITOR Nicotinamide (vitamin B3) prevents photocarcinogenesis in mice (Gensler et al., 1999) and photoimmunosuppression in humans (Damian, 2010). Actinic keratoses (AKs) strongly predict nonmelanoma skin cancer risk (Green and Battistutta, 1990). These phase II studies aimed to determine whether oral nicotinamide, at different doses, reduced AKs in sun-damaged individuals. Healthy, immune-competent volunteers with X4 palpable AKs (face, scalp and upper limbs) were recruited from Royal Prince Alfred Hospital Dermatology Clinics, Sydney, Australia. The study protocols (ACTRN12609000490279; ACTRN12610000689077; http://www. anzctr.org.au) adhered to Helsinki Guidelines and were approved by the Sydney South West Area Health Service and University of Sydney ethics committees. All volunteers provided written informed consent. Participants were randomly assigned (1:1) to take nicotinamide 500 mg (Nature’s Own, Virginia, Queensland, Australia) or matched placebo (Australian Custom Pharmaceuticals, Sydney, New South Wales, Australia) twice daily (Study 1) or once daily (Study 2) for 4 months. The treatment allocation sequence was determined by a computergenerated randomization list prepared using a permuted blocks method (block size 6) by an investigator (DLD) not involved in AK assessment. Participants underwent complete skin examination before randomization, were encouraged to use daily sunscreen, and remained blinded throughout the study. At baseline, 2 and 4 months, palpable AKs were identified visually and by touch by a blinded observer (DS), counted and documented on a body grid chart. At baseline and 2 months, full blood count, creatinine, and liver function were assessed. A target of 36 patients was selected for Study 1 based on clinical judgement as this was our first pilot trial of oral nicotinamide. A conservative

Detection of Primary Melanoma in Individuals at Extreme High Risk A Prospective 5-Year Follow-up Study

IMPORTANCE The clinical phenotype and certain predisposing genetic mutations that confer increased melanoma risk are established; however, no consensus exists regarding optimal screening for such individuals. Early identification remains the most important intervention in reducing melanoma mortality. OBJECTIVE To evaluate the impact of full-body examinations every 6 months supported by dermoscopy and total-body photography (TBP) on all patients and sequential digital dermoscopy imaging (SDDI), when indicated, on detecting primary melanoma in an extreme-risk population. DESIGN, SETTING, AND PARTICIPANTS Prospective observational study from February 2006 to February 2011, with patients recruited from Sydney Melanoma Diagnostic Centre and Melanoma Institute Australia who had a history of invasive melanoma and dysplastic nevus syndrome, history of invasive melanoma and at least 3 first-degree or second-degree relatives with prior melanoma, history of at least 2 primary invasive melanomas, or a CDKN2A or CDK4 gene mutation. EXPOSURES Six-month full-body examination compared with TBP. For equivocal lesions, SDDI short term (approximately 3 months) or long term (≥6 months), following established criteria, was performed. Atypical lesions were excised. MAIN OUTCOMES AND MEASURES New primary melanoma numbers, characteristics, and cumulative incidence in each patient subgroup; effect of diagnostic aids on new melanoma identification. RESULTS In 311 patients with a median (interquartile range [IQR]) follow-up of 3.5 (2.4-4.2) years, 75 primary melanomas were detected, 14 at baseline visit. Median (IQR) Breslow thickness of postbaseline incident melanomas was in situ (in situ to 0.60 mm). Thirty-eight percent were detected using TBP and 39% with SDDI. Five melanomas were greater than 1 mm Breslow thickness, 3 of which were histologically desmoplastic; the other 2 had nodular components. The benign to malignant excision ratio was 1.6:1 for all lesions excised and 4.4:1 for melanocytic lesions. Cumulative risk of developing a novel primary melanoma was 12.7% by year 2, with new primary melanoma incidence during the final 3 years of follow-up half of that observed during the first 2 years (incidence density ratio, 0.43 [95% CI, 0.25-0.74]; P = .002). CONCLUSIONS AND RELEVANCE Monitoring patients at extreme risk with TBP and SDDI assisted with early diagnosis of primary melanoma. Hypervigilance for difficult-to-detect thick melanoma subtypes is crucial.

SWI/SNF: A chromatin-remodelling complex with a role in carcinogenesis

SWI/SNF is a chromatin-remodelling complex that makes DNA that has been compacted into nucleosomes accessible to transcription factors and repair enzymes. It does this by displacing DNA from the core histone surface. SWI/SNF consists of at least nine subunits, including one of two alternative ATPase subunits, BRM or BRG-1, that provide the energy for remodelling. As it regulates access to DNA it controls many aspects of normal cellular function. Limited studies have recently linked loss of function of SWI/SNF subunits to cancer development, suggesting that it may be a tumor suppressor complex. As epigenetic repression regulates SWI/SNF component expression at least in some cases, restoration of function is therapeutically promising for cancer treatment. Considerably more research is required into deregulation of SWI/SNF in cancer and determination of how this affects tumor development. This is an exciting but poorly understood molecule that may have a role in carcinogenesis.

Dermoscopic evaluation of nodular melanoma

IMPORTANCE Nodular melanoma (NM) is a rapidly progressing potentially lethal skin tumor for which early diagnosis is critical. OBJECTIVE To determine the dermoscopy features of NM. DESIGN Eighty-three cases of NM, 134 of invasive non-NM, 115 of nodular benign melanocytic tumors, and 135 of nodular nonmelanocytic tumors were scored for dermoscopy features using modified and previously described methods. Lesions were separated into amelanotic/hypomelanotic or pigmented to assess outcomes. SETTING Predominantly hospital-based clinics from 5 continents. MAIN OUTCOME MEASURES Sensitivity, specificity, and odds ratios for features/models for the diagnosis of melanoma. RESULTS Nodular melanoma occurred more frequently as amelanotic/hypomelanotic (37.3%) than did invasive non-NM (7.5%). Pigmented NM had a more frequent (compared with invasive non-NM; in descending order of odds ratio) symmetrical pigmentation pattern (5.8% vs 0.8%), large-diameter vessels, areas of homogeneous blue pigmentation, symmetrical shape, predominant peripheral vessels, blue-white veil, pink color, black color, and milky red/pink areas. Pigmented NM less frequently displayed an atypical broadened network, pigment network or pseudonetwork, multiple blue-gray dots, scarlike depigmentation, irregularly distributed and sized brown dots and globules, tan color, irregularly shaped depigmentation, and irregularly distributed and sized dots and globules of any color. The most important positive correlating features of pigmented NM vs nodular nonmelanoma were peripheral black dots/globules, multiple brown dots, irregular black dots/globules, blue-white veil, homogeneous blue pigmentation, 5 to 6 colors, and black color. A model to classify a lesion as melanocytic gave a high sensitivity (>98.0%) for both nodular pigmented and nonnodular pigmented melanoma but a lower sensitivity for amelanotic/hypomelanotic NM (84%). A method for diagnosing amelanotic/hypomelanotic malignant lesions (including basal cell carcinoma) gave a 93% sensitivity and 70% specificity for NM. CONCLUSIONS AND RELEVANCE When a progressively growing, symmetrically patterned melanocytic nodule is identified, NM needs to be excluded.

Hotspot Mutation of Brahma in Non-Melanoma Skin Cancer

Mammalian SWItch/sucrose non fermentable (SWI/SNF) remodeling of chromatin modulates transcription and DNA repair. The Brahma (BRM) catalytic subunit of the SWI/SNF complex is one of two mutually exclusive subunits that provide energy for remodeling. BRM has been identified as an important cancer susceptibility locus; however, to date no mutations have been identified in the BRM gene. We performed genetic analysis of BRM in human non-melanoma skin cancers, precancerous lesions, and normal skin revealing a common nonsynonymous point mutation present in one of ten squamous cell and two of six basal cell carcinoma of the skin. This hotspot was not present in germ-line DNA from the same patients, nor in epithelial precancerous lesions. The observed G:C to T:A transversion is typical of mutations occurring following oxidative damage, such as that caused by UVA radiation. This previously unreported hotspot mutation occurs in a highly conserved region of the BRM gene.

Skin and systemic pharmacokinetics of tacrolimus following topical application of tacrolimus ointment in adults with moderate to severe atopic dermatitis

Background  Systemic exposure to tacrolimus following topical application of tacrolimus ointment is minimal. There are, however, no data on the distribution of tacrolimus in the skin.

Key points in the dermoscopic diagnosis of hypomelanotic melanoma and nodular melanoma

Nodular melanoma (NM) and amelanotic/hypomelanotic melanoma (AHM) often present a challenge to the diagnosing clinician. A significant proportion of AHM are nodular in nature. Such tumors may lack features of asymmetry and altered peripheral pigmentation routinely observed in other melanoma subtypes. This lack of distinguishing clinical features can potentially result in delayed diagnosis or inappropriate treatment. This review highlights the key points in evaluating the range of lesions where AHM or NM are considered in the differential diagnosis and summarizes current evidence in relation to pigmented and vascular dermoscopic diagnostic criteria for both.