Faculty Bibliography

Persistent paraprotein production in plasma cells necessitates a highly developed rough endoplasmic recticulum (ER) that is exquisitely sensitive to perturbations in protein synthesis. Targeting ER stress-related signaling has been clinically validated in the treatment of multiple myeloma (MM) as evidenced by the response to treatment with bortezomib (BTZ). Despite impressive response rates, BTZ carries the potential for serious side effects, and the development of resistance to BTZ is a clinical issue. We therefore sought to identify novel drug combinations that effectively generate ER stress. Here, we report that sulforaphane, a naturally occurring isothiocyanate found in cruciferous vegetables, synergistically enhances the cytotoxicity of arsenic trioxide (ATO), an agent that has shown clinical activity in MM, in a panel of MM cell lines. As single agents, both 1 muM sulforaphane and 0.5 muM ATO have a modest effect on cellular proliferation in a panel of MM lines. However, when the agents are administered in combination, cellular proliferation is dramatically reduced. For example, in PCNY-1 MM cells, 1 muM sulforaphane has no effect and 0.5muM ATO causes a 29% reduction in proliferation. However, when administered together, the agents enhance growth inhibition to 73%, with a CI of 0.632 indicative of synergy. Four out of 5 MM cell lines tested displayed sulforaphane and ATO synergy. Combination treatment resulted in enhanced apoptotic induction as demonstrated by cleavage of PARP. Enhanced induction of ER stress signaling and activation of the unfolded protein response (UPR) upon combination treatment was demonstrated by enhanced expression of the molecular chaperone HSP90 along with increased phosphorylation of PERK (an ER transmembrane kinase and proximal effector of the UPR) and eIF2 (translational initiation factor). Additionally, increased splicing of XBP1 (a transcription factor of UPR target genes) was apparent upon combination treatment as compared to treatment with either agent alone. Our results show that sulforaphane can synergistically sensitize MM cells to the cytotoxic effects of ATO through promotion of ER stress generating mechanisms. Based upon these promising results, further evaluation of this safe, natural product as an ATO sensitizer in a clinical trial of MM patients is warranted. Additionally, this approach holds the promise as a means to identify and clinically validate natural products effective in the treatment of MM and/or inhibition of progression of asymptomatic MM

ABSTRACT: BACKGROUND: Brain metastases afflict approximately half of patients with metastatic melanoma (MM) and small cell lung cancer (SCLC) and represent the direct cause of death in 60 to 70% of those affected. Standard of care remains ineffective in both types of cancer with the challenge of overcoming the blood brain barrier (BBB) exacerbating the clinical problem. Our purpose is to determine and characterize the potential of albendazole (ABZ) as a cytotoxic and radiosensitizing agent against MM and SCLC cells. METHODS: Here, ABZ's mechanism of action as a DNA damaging and microtubule disrupting agent is assessed through analysis of histone H2AX phosphorylation and cell cyle progression. The cytotoxicity of ABZ alone and in combination with radiation therapy is determined though clonogenic cell survival assays in a panel of MM and SCLC cell lines. We further establish ABZ's ability to act synergistically as a radio-sensitizer through combination index calculations and apoptotic measurements of poly (ADP-ribose) polymerase (PARP) cleavage. RESULTS: ABZ induces DNA damage as measured by increased H2AX phosphorylation. ABZ inhibits the growth of MM and SCLC at clinically achievable plasma concentrations. At these concentrations, ABZ arrests MM and SCLC cells in the G2/M phase of the cell cycle after 12 hours of treatment. Exploiting the notion that cells in the G2/M phase are the most sensitive to radiation therapy, we show that treatment of MM and SCLC cells treated with ABZ renders them more sensitive to radiation in a synergistic fashion. Additionally, MM and SCLC cells co-treated with ABZ and radiation exhibit increased apoptosis at 72 hours. CONCLUSIONS: Our study suggests that the orally available antihelminthic ABZ acts as a potent radiosensitizer in MM and SCLC cell lines. Further evaluation of ABZ in combination with radiation as a potential treatment for MM and SCLC brain metastases is warranted

A six-week-old girl presented with a segmental, focally atrophic, vascular patch in the diaper area, present since birth. It had undergone minimal proliferation, but had ulcerated. Evaluation to rule out LUMBAR (Lower body hemangioma/Lipoma or other cutaneous anomalies, Urogenital anomalies, Myelopathy, Bony deformities, Anorectal/Arterial anomalies, and Renal anomalies) syndrome, which included ultrasound and Doppler examination of the abdomen, spine, and pelvis, was negative. We report a unique case of an ulcerated, segmental abortive hemangioma of the anogenital area with excellent clinical response to topical timolol gel.

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

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

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