Faculty Bibliography

Most metastatic melanomas are refractory to current available therapy, underscoring the need to identify new effective treatments. Sorafenib, a multikinase inhibitor of the mitogen-activated protein kinase signaling pathway, showed promise in earlier stages of clinical development, but ultimately failed to demonstrate efficacy as a single agent in the treatment of melanoma. In order to enhance the efficacy of sorafenib in the treatment of melanoma, we tested over 2,000 naturally occurring compounds and marketed drugs in the presence of sorafenib in chemoresistant human melanoma cell lines also resistant to sorafenib-induced apoptosis. Of the 9 compounds identified as sorafenib sensitizers, we prioritized the cholesterol-lowering agent fluvastatin, based on its favorable pharmacokinetics and safety profile. Our results demonstrate that fluvastatin at 1 muM, a level safely achieved through oral administration, dramatically enhances the growth-inhibitory activity of clinically achievable concentrations of sorafenib in M14 and SKM-173 melanoma cells, with a 3.2- and 3.6-fold reduction in sorafenib 50% growth inhibition (GI50), respectively. Similar effects were observed for other melanoma cell lines. Combination indices analysis revealed a synergistic relationship between the two agents. Fluvastatin enhances sorafenib-mediated apoptosis as revealed through enhanced cleavage of poly (ADP-ribose) polymerase. In combination with sorafenib, fluvastatin treatment results in reduced levels of activated murine thymoma viral oncogene homolog along with enhanced levels of activated c-Jun N-terminal kinase. Sensitization to sorafenib is unique to fluvastatin, as other statins (pravastatin and simvastatin) do not enhance sorafenib-mediated growth inhibition. These promising results warrant further investigation into the clinical applicability of fluvastatin as an agent for enhancing the efficacy of sorafenib in the treatment of melanoma

Oculocutaneous albinism (OCA) is a group of genetic disorders characterized by hypopigmentation of the skin, hair, and eyes. Affected individuals experience reduced visual acuity and substantially increased skin cancer risk. There are four major types of OCA (OCA1-OCA4) that result from disruption in production of melanin from tyrosine. Current treatment options for individuals with OCA are limited to attempts to correct visual problems and counseling to promote use of sun protective measures. However, Onojafe et al., reporting in this issue of the JCI, provide hope for a new treatment approach for OCA, as they demonstrate that treating mice that model OCA-1b with nitisinone, which is FDA approved for treating hereditary tyrosinemia type 1, elevates plasma tyrosine levels, and increases eye and hair pigmentation

Stress induced by buildup of misfolded proteins in the endoplasmic reticulum (ER) triggers the unfolded protein response (UPR). Failure by the UPR to restore homeostasis can trigger apoptosis. We have shown chronic UPR activation in tyrosinase and Tyrp1 mutant melanocytes, where tyrosinase is retained in the ER, without concomitant loss of viability, suggesting that melanocytes adapt to ER stress. Identifying adaptive mechanisms has implications for treatment of melanocyte disorders. For example, UPR activation may permit adaptation to hypoxia and play a role in melanomagenesis. Thus melanoma therapies targeting the UPR are being tested. The UPR may also play a role in vitiligo. Xbp1 (a key UPR transcription factor) polymorphisms are associated with increased risk of vitiligo, while ER dilation in perilesional melanocytes suggests ER stress. The UPR consists of three pathways regulated by IRE1, ATF6 and PERK. Prolonged IRE1 signaling in stressed cells promotes survival, while sustained PERK activity promotes apoptosis. OCA2 mutations result in hypopigmentation due, in part, to ER retention of tyrosinase, but do not result in loss of viability. We therefore investigated the UPR in Oca2-(null) melanocytes. Wildtype and Oca2-melanocytes were treated with ER stressors thapsigargin or tunicamycin and UPR activation was monitored by RT-PCR and Western blot analysis. Ire1 expression was increased in Oca2-melanocytes compared to wildtype cells. However, downstream signaling was not activated, with no splicing of Ire1 targeted Xbp1. Expression of Perk and its downstream effector Atf4 were decreased in Oca2-melanocytes. Upon ER stress, Ire1 expression and Xbp1 splicing increased in both cell lines indicating UPR activation. Typically, UPR activation leads to Perk-mediated phosphorylation of eIF2alpha. Remarkably, levels of p-eIF2alpha were markedly diminished in stressed Oca2-cells. Expression of proapoptotic CHOP was still induced in Oca2-melanocytes, but did not result in significant cell death. Our da!

BACKGROUND: Psoriasis adversely affects health-related quality of life (HRQoL) in adults; however, little information exists about its impact on children and adolescents. OBJECTIVE: The effect of etanercept therapy on HRQoL compared with placebo was evaluated in children and adolescents with moderate to severe plaque psoriasis. METHODS: HRQoL data were collected from patients 4 to 17 years of age in a randomized, double-blind, placebo-controlled, North American, phase III study of etanercept. Instruments for assessing HRQoL included the Children's Dermatology Life Quality Index (CDLQI), Pediatric Quality of Life Inventory (PedsQL), Stein Impact on Family Scale, and Harter Self-Perception Profile for Children. RESULTS: Baseline CDLQI and PedsQL scores revealed reduced HRQoL in patients with psoriasis relative to comparative populations. Patients treated with etanercept demonstrated significantly higher mean percentage improvement in total CDLQI scores from baseline to week 12 compared with those treated with placebo (52.3% etanercept vs 17.5% placebo [P = .0001]). At week 12, patients who achieved 75% improvement in their Psoriasis Area and Severity Index score had higher percentage improvements from baseline in total CDLQI scores than those who did not have 75% improvement in Psoriasis Area and Severity Index score. LIMITATIONS: The PedsQL, Stein scale, and Harter profile demonstrated limited improvement in patients' HRQoL, suggesting that these scales may not be sensitive to issues that are relevant to children with psoriasis and their families. CONCLUSION: Etanercept therapy had a clinically and statistically meaningful impact on disease-specific quality of life (CDLQI) and a clinically meaningful impact on general quality of life (PedsQL) in children and adolescents with moderate to severe plaque psoriasis

Radiation therapy (RT) represents an important adjuvant treatment modality for high-risk squamous cell carcinomas (SCCs). Despite the frequency of aggressive cutaneous and extracutaneous malignancies, there have been relatively few reports of RT in individuals with xeroderma pigmentosum (XP). We describe 2 adolescent boys with XP and high-risk SCCs of the skin that were treated with standard RT regimens without acute or chronic complications. After follow-up periods of 2 and 7 years, both of these patients had developed fewer skin cancers on the treated side of the face. A review of reported cases revealed that XP patients generally have normal cellular and clinical responses to ionizing radiation, which reflects the specificity of their nucleotide excision repair defect for ultraviolet radiation-induced DNA damage

Summary Accumulation of proteins in the endoplasmic reticulum (ER) triggers the unfolded protein response (UPR), comprising three signaling pathways initiated by Ire1, Perk and Atf6 respectively. Unfolded protein response activation was compared in chemically stressed murine wildtype melanocytes and mutant melanocytes that retain tyrosinase in the ER. Thapsigargin, an ER stressor, activated all pathways in wildtype melanocytes, triggering Caspase 12-mediated apoptosis at toxic doses. Albino melanocytes expressing mutant tyrosinase showed evidence of ER stress with increased Ire1 expression, but the downstream effector, Xbp1, was not activated even following thapsigargin treatment. Attenuation of Ire1 signaling was recapitulated in wildtype melanocytes treated with thapsigargin for 8 days, with diminished Xbp1 activation observed after 4 days. Atf6 was also activated in albino melanocytes, with no response to thapsigargin, while the Perk pathway was not activated and thapsigargin treatment elicited robust expression of the downstream effector CCAAT-enhancer-binding protein homologous protein. Thus, melanocytes adapt to ER stress by attenuating two UPR pathways

Summary Background Hair loss is an unwelcome event at any age, but it can be particularly distressing for adolescents and their families. While androgenetic alopecia (AGA) is the most common form of hair loss in adults, little is known about its prevalence, clinical features and response to treatments in the paediatric population. Objectives To better characterize the causes of alopecia in a paediatric population. Methods We performed a retrospective chart review to identify all patients with hair loss seen in an academic paediatric dermatology practice at New York University over a 12-year period to better characterize the causes of alopecia in this population. We review the clinical and histological features, natural progression and associated laboratory abnormalities of AGA in 57 paediatric patients. Results AGA was identified as the most frequent cause of hair loss in adolescents and the second most common diagnosis overall. The male to female ratio was 2 : 1 and the average age at initial presentation with AGA was 14.8 years. Adolescent girls had diffuse thinning or thinning at the crown, and boys frequently presented with female pattern hair loss. When biopsies were performed, perifollicular inflammation was a common finding. A family history of AGA was reported in 83% of patients. Laboratory evaluation for androgens revealed polycystic ovarian syndrome in three girls and late-onset congenital adrenal hyperplasia in one boy. Conclusions AGA is the most common form of hair loss in adolescents, and can be the presenting sign of an underlying endocrine disorder. An accurate and timely diagnosis is essential for appropriate medical and psychosocial intervention when warranted