Clinical Focus


  • Skin Cancer
  • Cancer > Cutaneous (Dermatologic) Oncology
  • Hair disorders
  • Genetic Skin Disease
  • Dermatology

Academic Appointments


Professional Education


  • Residency:Stanford University Medical Center (1997) CA
  • Board Certification: Dermatology, American Board of Dermatology (1998)
  • Internship:Stanford University Medical Center (1994) CA
  • Medical Education:UCSD School of Medicine (1993) CA

Current Research and Scholarly Interests


Our lab studies skin stem cells to understand mechanisms of tissue regeneration and carcinogenesis. We have a longstanding interest in the mechanisms of Sonic hedgehog (Shh) signaling in the hair follicle and n the pathogenesis of the most common human tumor, basal cell carcinoma (BCCs) of the skin. We have provided clinical evidence for the first hedgehog pathway inhibitor and are developing novel targets for next generation inhibitors that target the transcription factor Gli. We are studying the mechanisms of tumor evolution and the development of chemoresistance to targeted agents in both patients and mouse models using genomics and bioinformatic methods followed by functional validation.

We are also interested in the mechanisms of human skin development and early ectodermal differentiation and have developed in vitro human skin differentiation from embryonic stem cells. Using this system, we are exploring how early ectoderm commits to stratified epithelium. We have used our system, in collaboration with other labs at Stanford, to manufacture corrected human epidermal sheets from patient-specific iPS cells.

Clinical Trials


  • A Phase II Study of Efficacy and Safety in Patients With Locally Advanced or Metastatic Basal Cell Carcinoma Not Recruiting

    This study will assess the efficacy and safety of oral treatment with two dose levels of LDE225 in patients with locally advanced or metastatic BCC.

    Stanford is currently not accepting patients for this trial. For more information, please contact Shruthi Rangaraj, (650) 721 - 7159.

    View full details

  • Characteristics of Patients With Dystrophic Epidermolysis Bullosa Recruiting

    Dystrophic epidermolysis bullosa (DEB) is a group of diseases caused by genetic mutations in the gene for type VII collagen. DEB can be severe or mild with the recessive disease usually being more severe. Patients with DEB develop large, severely painful blisters and open wounds from minor trauma to their skin. We are screening subjects with DEB to evaluate characteristics of the subjects and their cells in order to develop new strategies of therapy.

    View full details

  • A Phase 1 Study of IPI-926 in Patients With Advanced and/or Metastatic Solid Tumor Malignancies Not Recruiting

    The primary objectives of the study are: - To determine the safety and the maximum tolerated dose (MTD) of IPI-926 - To examine the pharmacokinetic parameters of IPI-926 and its characterized major metabolite(s) - To recommend a dose and schedule of IPI-926 for subsequent studies

    Stanford is currently not accepting patients for this trial. For more information, please contact Shruthi Rangaraj, (650) 721 - 7159.

    View full details

  • Vismodegib in Treating Patients With Basal Cell Carcinoma Not Recruiting

    The purpose of this study is to learn about the effect of vismodegib on sporadic basal cell carcinoma (BCCs) prior to surgical removal.

    Stanford is currently not accepting patients for this trial. For more information, please contact Irene Bailey, 650-721-7149.

    View full details

  • Arsenic Trioxide in Treating Patients With Basal Cell Carcinoma Not Recruiting

    This pilot clinical trial studies arsenic trioxide in treating patients with basal cell carcinoma. Drugs used in chemotherapy, such as arsenic trioxide, work in different ways to stop the growth of tumor cells, either by killing the cells or by stop them from dividing

    Stanford is currently not accepting patients for this trial. For more information, please contact Irene Bailey-Healy, 408-892-7261.

    View full details

  • A Study of Vismodegib (GDC-0449) in Patients With Locally Advanced or Metastatic Basal Cell Carcinoma Not Recruiting

    This is an open-label, non-comparative, multicenter, expanded access study of Vismodegib (GDC-0449) in patients with locally advanced basal cell carcinoma (BCC) or metastatic BCC (mBCC) who are otherwise without satisfactory treatment options.

    Stanford is currently not accepting patients for this trial. For more information, please contact Shruthi Rangaraj, (650) 721 - 7159.

    View full details

  • Pilot LDE225 in Locally Advanced or Metastatic BCC + Previously Tx Non-LDE225 Smoothened Inhibitors Not Recruiting

    This is a prospective single-center, open label, pilot study to investigate the safety and efficacy of LDE225 in patients with locally advanced or metastatic basal cell carcinoma. Primary Objectives: • To explore the effects of oral LDE225 on the Progression Free Survival (PFS) of individuals with locally advanced or metastatic BCC who have been previously treated with a non-LDE225 Smo inhibitor. Secondary Objectives: - To evaluate the effect of oral LDE225 on tumor tissue biomarkers of BCC activation (Gii 1, 2, Patched 1,2 and Ki67) in individuals which are non-na"ive to Smo inhibitors other than LDE225, at baseline and at end-of-treatment - To describe adverse effects of oral LDE225 in individuals with a history of non-LDE225 Smo inhibitor usage - To assess the overall survival rates of individuals with locally advanced BCC or metastatic BCC who have previously taken a non-LDE225 Smo inhibitor after treatment with LDE225

    Stanford is currently not accepting patients for this trial. For more information, please contact Shruthi Rangaraj, 650-721-7159.

    View full details

  • A Study of GDC-0449 (Hedgehog Pathway Inhibitor) in Patients Treated With GDC-0449 in a Previous Genentech-Sponsored Phase I or II Cancer Study Not Recruiting

    This is a multicenter, open-label extension study. Patients receiving GDC-0449 in a Genentech-sponsored study who have completed the parent study or who continue to receive GDC-0449 at the time of the parent study closure are eligible for continued treatment on this protocol.

    Stanford is currently not accepting patients for this trial. For more information, please contact Shruthi Rangaraj, (650) 721 - 7159.

    View full details

  • A Study in Advanced Cancer Recruiting

    The purpose of this study is to find a recommended dose level and schedule of dosing LY2940680 that can safely be taken by patients with advanced cancer. The study will also explore the changes in a cancer marker level in skin, hair follicles, buccal cells, and tumor cells. Finally, the study will help document any antitumor activity this drug may have.

    View full details

  • A Study Evaluating the Efficacy and Safety of Vismodegib (GDC-0449, Hedgehog Pathway Inhibitor) in Patients With Advanced Basal Cell Carcinoma Not Recruiting

    This is a Phase II, single-arm, two-cohort multicenter clinical trial evaluating the efficacy and safety of vismodegib (GDC-0449) in patients with advanced basal cell carcinoma. All patients will receive vismodegib until evidence of progression, intolerable toxicities most probably attributable to vismodegib, or withdrawal from the study.

    Stanford is currently not accepting patients for this trial. For more information, please contact Katherine Connors, (650) 721 - 7159.

    View full details

2013-14 Courses


Journal Articles


  • Partial Proteasome Inhibitors Induce Hair Follicle Growth by Stabilizing ß-Catenin. Stem cells Yucel, G., Van Arnam, J., Means, P. C., Huntzicker, E., Altindag, B., Lara, M. F., Yuan, J., Kuo, C., Oro, A. E. 2014; 32 (1): 85-92

    Abstract

    The activation of tissue stem cells from their quiescent state represents the initial step in the complex process of organ regeneration and tissue repair. While the identity and location of tissue stem cells are becoming known, how key regulators control the balance of activation and quiescence remains mysterious. The vertebrate hair is an ideal model system where hair cycling between growth and resting phases is precisely regulated by morphogen signaling pathways, but how these events are coordinated to promote orderly signaling in a spatial and temporal manner remains unclear. Here, we show that hair cycle timing depends on regulated stability of signaling substrates by the ubiquitin-proteasome system. Topical application of partial proteasomal inhibitors (PaPIs) inhibits epidermal and dermal proteasome activity throughout the hair cycle. PaPIs prevent the destruction of the key anagen signal β-catenin, resulting in more rapid hair growth and dramatically shortened telogen. We show that PaPIs induce excess β-catenin, act similarly to the GSK3β antagonist LiCl, and antagonize Dickopf-related protein-mediated inhibition of anagen. PaPIs thus represent a novel class of hair growth agents that act through transiently modifying the balance of stem cell activation and quiescence pathways. Stem Cells 2014;32:85-92.

    View details for DOI 10.1002/stem.1525

    View details for PubMedID 23963711

  • State-dependent signaling by Cav1.2 regulates hair follicle stem cell function. Genes & development Yucel, G., Altindag, B., Gomez-Ospina, N., Rana, A., Panagiotakos, G., Lara, M. F., Dolmetsch, R., Oro, A. E. 2013; 27 (11): 1217-1222

    Abstract

    The signals regulating stem cell activation during tissue regeneration remain poorly understood. We investigated the baldness associated with mutations in the voltage-gated calcium channel (VGCC) Cav1.2 underlying Timothy syndrome (TS). While hair follicle stem cells express Cav1.2, they lack detectable voltage-dependent calcium currents. Cav1.2(TS) acts in a dominant-negative manner to markedly delay anagen, while L-type channel blockers act through Cav1.2 to induce anagen and overcome the TS phenotype. Cav1.2 regulates production of the bulge-derived BMP inhibitor follistatin-like1 (Fstl1), derepressing stem cell quiescence. Our findings show how channels act in nonexcitable tissues to regulate stem cells and may lead to novel therapeutics for tissue regeneration.

    View details for DOI 10.1101/gad.216556.113

    View details for PubMedID 23752588

  • GLI activation by atypical protein kinase C ?/? regulates the growth of basal cell carcinomas. Nature Atwood, S. X., Li, M., Lee, A., Tang, J. Y., Oro, A. E. 2013; 494 (7438): 484-488

    Abstract

    Growth of basal cell carcinomas (BCCs) requires high levels of hedgehog (HH) signalling through the transcription factor GLI. Although inhibitors of membrane protein smoothened (SMO) effectively suppress HH signalling, early tumour resistance illustrates the need for additional downstream targets for therapy. Here we identify atypical protein kinase C ι/λ (aPKC-ι/λ) as a novel GLI regulator in mammals. aPKC-ι/λ and its polarity signalling partners co-localize at the centrosome and form a complex with missing-in-metastasis (MIM), a scaffolding protein that potentiates HH signalling. Genetic or pharmacological loss of aPKC-ι/λ function blocks HH signalling and proliferation of BCC cells. Prkci is a HH target gene that forms a positive feedback loop with GLI and exists at increased levels in BCCs. Genome-wide transcriptional profiling shows that aPKC-ι/λ and SMO control the expression of similar genes in tumour cells. aPKC-ι/λ functions downstream of SMO to phosphorylate and activate GLI1, resulting in maximal DNA binding and transcriptional activation. Activated aPKC-ι/λ is upregulated in SMO-inhibitor-resistant tumours and targeting aPKC-ι/λ suppresses signalling and growth of resistant BCC cell lines. These results demonstrate that aPKC-ι/λ is critical for HH-dependent processes and implicates aPKC-ι/λ as a new, tumour-selective therapeutic target for the treatment of SMO-inhibitor-resistant cancers.

    View details for DOI 10.1038/nature11889

    View details for PubMedID 23446420

  • Rapid genetic analysis of epithelial-mesenchymal signaling during hair regeneration. Journal of visualized experiments : JoVE Woo, W., Atwood, S. X., Zhen, H. H., Oro, A. E. 2013

    Abstract

    Hair follicle morphogenesis, a complex process requiring interaction between epithelia-derived keratinocytes and the underlying mesenchyme, is an attractive model system to study organ development and tissue-specific signaling. Although hair follicle development is genetically tractable, fast and reproducible analysis of factors essential for this process remains a challenge. Here we describe a procedure to generate targeted overexpression or shRNA-mediated knockdown of factors using lentivirus in a tissue-specific manner. Using a modified version of a hair regeneration model, we can achieve robust gain- or loss-of-function analysis in primary mouse keratinocytes or dermal cells to facilitate study of epithelial-mesenchymal signaling pathways that lead to hair follicle morphogenesis. We describe how to isolate fresh primary mouse keratinocytes and dermal cells, which contain dermal papilla cells and their precursors, deliver lentivirus containing either shRNA or cDNA to one of the cell populations, and combine the cells to generate fully formed hair follicles on the backs of nude mice. This approach allows analysis of tissue-specific factors required to generate hair follicles within three weeks and provides a fast and convenient companion to existing genetic models.

    View details for DOI 10.3791/4344

    View details for PubMedID 23486463

  • Hedgehog pathway inhibition and the race against tumor evolution JOURNAL OF CELL BIOLOGY Atwood, S. X., Chang, A. L., Oro, A. E. 2013: 45-49
  • Efficacy and Safety of Vismodegib in Advanced Basal-Cell Carcinoma NEW ENGLAND JOURNAL OF MEDICINE Sekulic, A., Migden, M. R., Oro, A. E., Dirix, L., Lewis, K. D., Hainsworth, J. D., Solomon, J. A., Yoo, S., Arron, S. T., Friedlander, P. A., Marmur, E., Rudin, C. M., Chang, A. L., Low, J. A., Mackey, H. M., Yauch, R. L., Graham, R. A., Reddy, J. C., Hauschild, A. 2012; 366 (23): 2171-2179

    Abstract

    Alterations in hedgehog signaling are implicated in the pathogenesis of basal-cell carcinoma. Although most basal-cell carcinomas are treated surgically, no effective therapy exists for locally advanced or metastatic basal-cell carcinoma. A phase 1 study of vismodegib (GDC-0449), a first-in-class, small-molecule inhibitor of the hedgehog pathway, showed a 58% response rate among patients with advanced basal-cell carcinoma.In this multicenter, international, two-cohort, nonrandomized study, we enrolled patients with metastatic basal-cell carcinoma and those with locally advanced basal-cell carcinoma who had inoperable disease or for whom surgery was inappropriate (because of multiple recurrences and a low likelihood of surgical cure, or substantial anticipated disfigurement). All patients received 150 mg of oral vismodegib daily. The primary end point was the independently assessed objective response rate; the primary hypotheses were that the response rate would be greater than 20% for patients with locally advanced basal-cell carcinoma and greater than 10% for those with metastatic basal-cell carcinoma.In 33 patients with metastatic basal-cell carcinoma, the independently assessed response rate was 30% (95% confidence interval [CI], 16 to 48; P=0.001). In 63 patients with locally advanced basal-cell carcinoma, the independently assessed response rate was 43% (95% CI, 31 to 56; P<0.001), with complete responses in 13 patients (21%). The median duration of response was 7.6 months in both cohorts. Adverse events occurring in more than 30% of patients were muscle spasms, alopecia, dysgeusia (taste disturbance), weight loss, and fatigue. Serious adverse events were reported in 25% of patients; seven deaths due to adverse events were noted.Vismodegib is associated with tumor responses in patients with locally advanced or metastatic basal-cell carcinoma. (Funded by Genentech; Erivance BCC ClinicalTrials.gov number, NCT00833417.).

    View details for Web of Science ID 000304863400006

    View details for PubMedID 22670903

  • Translocation Affecting Sonic Hedgehog Genes in Basal-Cell Carcinoma NEW ENGLAND JOURNAL OF MEDICINE Gomez-Ospina, N., Chang, A. L., Qu, K., Oro, A. E. 2012; 366 (23): 2233-2234

    View details for Web of Science ID 000304863400029

    View details for PubMedID 22670922

  • Shh maintains dermal papilla identity and hair morphogenesis via a Noggin-Shh regulatory loop GENES & DEVELOPMENT Woo, W., Zhen, H. H., Oro, A. E. 2012; 26 (11): 1235-1246

    Abstract

    During hair follicle morphogenesis, dermal papillae (DPs) function as mesenchymal signaling centers that cross-talk with overlying epithelium to regulate morphogenesis. While the DP regulates hair follicle formation, relatively little is known about the molecular basis of DP formation. The morphogen Sonic hedgehog (Shh) is known for regulating hair follicle epithelial growth, with excessive signaling resulting in basal cell carcinomas. Here, we investigate how dermal-specific Shh signaling contributes to DP formation and hair growth. Using a Cre-lox genetic model and RNAi in hair follicle reconstitution assays, we demonstrate that dermal Smoothened (Smo) loss of function results in the loss of the DP precursor, the dermal condensate, and a stage 2 hair follicle arrest phenotype reminiscent of Shh(-/-) skin. Surprisingly, dermal Smo does not regulate cell survival or epithelial proliferation. Rather, molecular screening and immunostaining studies reveal that dermal Shh signaling controls the expression of a subset of DP-specific signature genes. Using a hairpin/cDNA lentiviral system, we show that overexpression of the Shh-dependent gene Noggin, but not Sox2 or Sox18, can partially rescue the dermal Smo knockdown hair follicle phenotype by increasing the expression of epithelial Shh. Our findings suggest that dermal Shh signaling regulates specific DP signatures to maintain DP maturation while maintaining a reciprocal Shh-Noggin signaling loop to drive hair follicle morphogenesis.

    View details for DOI 10.1101/gad.187401.112

    View details for Web of Science ID 000304767000010

    View details for PubMedID 22661232

  • Neuropilins are positive regulators of Hedgehog signal transduction GENES & DEVELOPMENT Hillman, R. T., Feng, B. Y., Ni, J., Woo, W., Milenkovic, L., Gephart, M. G., Teruel, M. N., Oro, A. E., Chen, J. K., Scott, M. P. 2011; 25 (22): 2333-2346

    Abstract

    The Hedgehog (Hh) pathway is essential for vertebrate embryogenesis, and excessive Hh target gene activation can cause cancer in humans. Here we show that Neuropilin 1 (Nrp1) and Nrp2, transmembrane proteins with roles in axon guidance and vascular endothelial growth factor (VEGF) signaling, are important positive regulators of Hh signal transduction. Nrps are expressed at times and locations of active Hh signal transduction during mouse development. Using cell lines lacking key Hh pathway components, we show that Nrps mediate Hh transduction between activated Smoothened (Smo) protein and the negative regulator Suppressor of Fused (SuFu). Nrp1 transcription is induced by Hh signaling, and Nrp1 overexpression increases maximal Hh target gene activation, indicating the existence of a positive feedback circuit. The regulation of Hh signal transduction by Nrps is conserved between mammals and bony fish, as we show that morpholinos targeting the Nrp zebrafish ortholog nrp1a produce a specific and highly penetrant Hh pathway loss-of-function phenotype. These findings enhance our knowledge of Hh pathway regulation and provide evidence for a conserved nexus between Nrps and this important developmental signaling system.

    View details for DOI 10.1101/gad.173054.111

    View details for Web of Science ID 000297154700003

    View details for PubMedID 22051878

  • SnapShot: Hair Follicle Stem Cells CELL Woo, W., Oro, A. E. 2011; 146 (2): 334-U159

    View details for DOI 10.1016/j.cell.2011.07.001

    View details for Web of Science ID 000293013000015

    View details for PubMedID 21784251

  • Cell Migration: GSK3 beta Steers the Cytoskeleton's Tip CELL Yucel, G., Oro, A. E. 2011; 144 (3): 319-321

    Abstract

    Directed cell migration polarizes the cytoskeleton, allowing the cell to move toward migratory cues. In this issue, Wu et al. (2011) demonstrate that the glycogen synthase kinase 3? (GSK3?) controls microtubule architecture and polarized movement of skin stem cells during wound healing in mammals by regulating the microtubule crosslinking protein ACF7.

    View details for DOI 10.1016/j.cell.2011.01.023

    View details for Web of Science ID 000286973100002

    View details for PubMedID 21295692

  • MIM and Cortactin Antagonism Regulates Ciliogenesis and Hedgehog Signaling DEVELOPMENTAL CELL Bershteyn, M., Atwood, S. X., Woo, W., Li, M., Oro, A. E. 2010; 19 (2): 270-283

    Abstract

    The primary cilium is critical for transducing Sonic hedgehog (Shh) signaling, but the mechanisms of its transient assembly are poorly understood. Previously we showed that the actin regulatory protein Missing-in-Metastasis (MIM) regulates Shh signaling, but the nature of MIM's role was unknown. Here we show that MIM is required at the basal body of mesenchymal cells for cilia maintenance, Shh responsiveness, and de novo hair follicle formation. MIM knockdown results in increased Src kinase activity and subsequent hyperphosphorylation of the actin regulator Cortactin. Importantly, inhibition of Src or depletion of Cortactin compensates for the cilia defect in MIM knockdown cells, whereas overexpression of Src or phospho-mimetic Cortactin is sufficient to inhibit ciliogenesis. Our results suggest that MIM promotes ciliogenesis by antagonizing Src-dependent phosphorylation of Cortactin and describe a mechanism linking regulation of the actin cytoskeleton with ciliogenesis and Shh signaling during tissue regeneration.

    View details for DOI 10.1016/j.devcel.2010.07.009

    View details for Web of Science ID 000281090000012

    View details for PubMedID 20708589

  • I-BAR protein antagonism of endocytosis mediates directional sensing during guided cell migration JOURNAL OF CELL BIOLOGY Quinones, G. A., Jin, J., Oro, A. E. 2010; 189 (2): 353-367

    Abstract

    Although directed cellular migration facilitates the coordinated movement of cells during development and repair, the mechanisms regulating such migration remain poorly understood. Missing-in-metastasis (MIM) is a defining member of the inverse Bin/Amphiphysin/Rvs domain (I-BAR) subfamily of lipid binding, cytoskeletal regulators whose levels are altered in a number of cancers. Here, we provide the first genetic evidence that an I-BAR protein regulates directed cell migration in vivo. Drosophila MIM (dmim) is involved in Drosophila border cell migration, with loss of dmim function resulting in a lack of directional movement by the border cell cluster. In vivo endocytosis assays combined with genetic analyses demonstrate that the dmim product regulates directed cell movement by inhibiting endocytosis and antagonizing the activities of the CD2-associated protein/cortactin complex in these cells. These studies demonstrate that DMIM antagonizes pro-endocytic components to facilitate polarity and localized guidance cue sensing during directional cell migration.

    View details for DOI 10.1083/jcb.200910136

    View details for Web of Science ID 000276825200017

    View details for PubMedID 20385776

  • Augmenting Endogenous Wnt Signaling Improves Skin Wound Healing PLOS ONE Whyte, J. L., Smith, A. A., Liu, B., Manzano, W. R., Evans, N. D., Dhamdhere, G. R., Fang, M. Y., Chang, H. Y., Oro, A. E., Helms, J. A. 2013; 8 (10)

    Abstract

    Wnt signaling is required for both the development and homeostasis of the skin, yet its contribution to skin wound repair remains controversial. By employing Axin2(LacZ/+) reporter mice we evaluated the spatial and temporal distribution patterns of Wnt responsive cells, and found that the pattern of Wnt responsiveness varies with the hair cycle, and correlates with wound healing potential. Using Axin2(LacZ/LacZ) mice and an ear wound model, we demonstrate that amplified Wnt signaling leads to improved healing. Utilizing a biochemical approach that mimics the amplified Wnt response of Axin2(LacZ/LacZ) mice, we show that topical application of liposomal Wnt3a to a non-healing wound enhances endogenous Wnt signaling, and results in better skin wound healing. Given the importance of Wnt signaling in the maintenance and repair of skin, liposomal Wnt3a may have widespread application in clinical practice.

    View details for DOI 10.1371/journal.pone.0076883

    View details for Web of Science ID 000326029300061

    View details for PubMedID 24204695

  • Hedgehog pathway inhibition and the race against tumor evolution JOURNAL OF CELL BIOLOGY Atwood, S. X., Chang, A. L., Oro, A. E. 2012; 199 (2): 193-197

    Abstract

    Dependence of basal cell carcinomas and medulloblastomas on the Hedgehog pathway provides an opportunity for targeted or "personalized" therapy. The recent effectiveness and FDA approval of the first Smoothened inhibitors validates this class of agents, but has revealed drug-resistant tumor variants that bypass Smoothened inhibition. Here, we summarize the effectiveness of Hedgehog pathway inhibitors and highlight promising areas for the development of next generation drug antagonists for Hedgehog-dependent cancers.

    View details for DOI 10.1083/jcb.201207140

    View details for Web of Science ID 000309982400002

    View details for PubMedID 23071148

  • In Vivo Imaging of Human and Mouse Skin with a Handheld Dual-Axis Confocal Fluorescence Microscope JOURNAL OF INVESTIGATIVE DERMATOLOGY Ra, H., Piyawattanametha, W., Gonzalez-Gonzalez, E., Mandella, M. J., Kino, G. S., Solgaard, O., Leake, D., Kaspar, R. L., Oro, A., Contag, C. H. 2011; 131 (5): 1061-1066

    Abstract

    Advancing molecular therapies for the treatment of skin diseases will require the development of new tools that can reveal spatiotemporal changes in the microanatomy of the skin and associate these changes with the presence of the therapeutic agent. For this purpose, we evaluated a handheld dual-axis confocal (DAC) microscope that is capable of in vivo fluorescence imaging of skin, using both mouse models and human skin. Individual keratinocytes in the epidermis were observed in three-dimensional image stacks after topical administration of near-infrared (NIR) dyes as contrast agents. This suggested that the DAC microscope may have utility in assessing the clinical effects of a small interfering RNA (siRNA)-based therapeutic (TD101) that targets the causative mutation in pachyonychia congenita (PC) patients. The data indicated that (1) formulated indocyanine green (ICG) readily penetrated hyperkeratotic PC skin and normal callused regions compared with nonaffected areas, and (2) TD101-treated PC skin revealed changes in tissue morphology, consistent with reversion to nonaffected skin compared with vehicle-treated skin. In addition, siRNA was conjugated to NIR dye and shown to penetrate through the stratum corneum barrier when topically applied to mouse skin. These results suggest that in vivo confocal microscopy may provide an informative clinical end point to evaluate the efficacy of experimental molecular therapeutics.

    View details for DOI 10.1038/jid.2010.401

    View details for Web of Science ID 000289789900014

    View details for PubMedID 21191407

  • Laminin-511 and integrin beta-1 in hair follicle development and basal cell carcinoma formation BMC DEVELOPMENTAL BIOLOGY DeRouen, M. C., Zhen, H., Tan, S. H., Williams, S., Marinkovich, M. P., Oro, A. E. 2010; 10

    Abstract

    Initiation of the hair follicle placode and its subsequent growth, maturation and cycling in post-natal skin requires signaling interactions between epithelial cells and adjacent dermal cells and involves Shh signaling via the primary cilium. Previous reports have implicated laminins in hair follicle epithelial invagination.Here we use a human BCC model system and mouse mutants to re-evaluate the role of laminin-511 in epithelial invagination in the skin. Blocking laminin 511 and 332 in BCCs maintains primary cilia and Shh signalling, but prevents invagination. Similarly, in laminin-511 and dermal beta-1 integrin mutants, dermal papilla development and primary cilia formation are normal. Dermal beta-1 integrin mutants have normal hair follicle development.Our data provides support for a primary role of laminin-511 promoting hair follicle epithelial downgrowth without affecting dermal primary cilia and Shh target gene induction.

    View details for DOI 10.1186/1471-213X-10-112

    View details for Web of Science ID 000284878300001

    View details for PubMedID 21067603

  • BAR domain competition during directional cellular migration CELL CYCLE Quinones, G. A., Oro, A. E. 2010; 9 (13): 2522-2528

    Abstract

    While directed cellular migration facilitates the coordinated movement of cells during development and tissue repair, the precise mechanisms regulating the interplay between the extracellular environment, the actin cytoskeleton, and the overlying plasma membrane remain inadequately understood. The BAR domain family of lipid binding, actin cytoskeletal regulators are gaining greater appreciation for their role in these critical processes. BAR domain proteins are involved as both positive and negative regulators of endocytosis, membrane plasticity, and directional cell migration. This review focuses on the functional relationship between different classes of BAR domain proteins and their role in guiding cell migration through regulation of the endocytic machinery. Competition for key signaling substrates by positive and negative BAR domain endocytic regulators appears to mediate control of directional cell migration, and may have wider applicability to other trafficking functions associated with development and carcinogenesis.

    View details for DOI 10.4161/cc.9.13.12123

    View details for Web of Science ID 000281205400024

    View details for PubMedID 20581461

  • The Primary Cilium: A Small Yet Mighty Organelle JOURNAL OF INVESTIGATIVE DERMATOLOGY DeRouen, M. C., Oro, A. E. 2009; 129 (2): 264-265

    Abstract

    Primary cilia are small, cylindrical membrane protrusions on most vertebrate cell types. Despite an unassuming appearance, this organelle has proven to be a veritable nexus of tightly regulated cell-signal reception between the epithelium and mesenchyme. In this issue, Lehman et al. describe the necessity of Ift88 and intraflagellar transport for signal reception of the sonic hedgehog pathway in the dermal papilla of developing hair follicles.

    View details for DOI 10.1038/jid.2008.404

    View details for Web of Science ID 000262655600003

    View details for PubMedID 19148215

  • Laminin-511 is an epithelial message promoting dermal papilla development and function during early hair morphogenesis GENES & DEVELOPMENT Gao, J., DeRouen, M. C., Chen, C., Nguyen, M., Nguyen, N. T., Ido, H., Harada, K., Sekiguchi, K., Morgan, B. A., Miner, J. H., Oro, A. E., Marinkovich, M. P. 2008; 22 (15): 2111-2124

    Abstract

    Hair morphogenesis takes place through reciprocal epithelial and mesenchymal signaling; however, the mechanisms controlling signal exchange are poorly understood. Laminins are extracellular proteins that play critical roles in adhesion and signaling. Here we demonstrate the mechanism of how laminin-511 controls hair morphogenesis. Dermal papilla (DP) from laminin-511 mutants showed developmental defects by E16.5, including a failure to maintain expression of the key morphogen noggin. This maintenance was critical as exogenous introduction of noggin or sonic hedgehog (Shh) produced downstream from noggin was sufficient to restore hair follicle development in lama5(-/-) (laminin-511-null) skin. Hair development required the beta1 integrin binding but not the heparin binding domain of laminin-511. Previous studies demonstrated that Shh signaling requires primary cilia, microtubule-based signaling organelles. Laminin-511 mutant DP showed decreased length and structure of primary cilia in vitro and in vivo. Laminin-511, but not laminin-111, restored primary cilia formation in lama5(-/-) mesenchyme and triggered noggin expression in an Shh- and PDGF-dependent manner. Inhibition of laminin-511 receptor beta1 integrin disrupted DP primary cilia formation as well as hair development. These studies show that epithelial-derived laminin-511 is a critical early signal that directs ciliary function and DP maintenance as a requirement for hair follicle downgrowth.

    View details for DOI 10.1101/gad.1689908

    View details for Web of Science ID 000258117500012

    View details for PubMedID 18676816

  • Controlling hair follicle signaling pathways through polyubiquitination JOURNAL OF INVESTIGATIVE DERMATOLOGY Huntzicker, E. G., Oro, A. E. 2008; 128 (5): 1081-1087

    Abstract

    Hair follicle development and maintenance require precise reciprocal signaling interactions between the epithelium and underlying dermis. Three major developmental signaling pathways, Wnt, Sonic hedgehog, and NF-kappaB/Edar, are indispensable for this process and, when aberrantly activated, can lead to skin and appendage neoplasms. Recent data point to protein polyubiquitination as playing a central role in regulating the timing, duration, and location of signaling. Here we review how polyubiquitination regulates the stability and interaction of key signaling components that control hair follicle development and regeneration.

    View details for DOI 10.1038/sj.jid.5700957

    View details for Web of Science ID 000255250400006

    View details for PubMedID 18408747

  • A new role for an old friend: NFAT and stem cell quiescence CELL STEM CELL Oro, A. E. 2008; 2 (2): 104-106

    Abstract

    NFAT proteins are calcium-regulated transcription factors that play a critical role during the timing and activation of many vertebrate tissues. A recent paper in Cell (Horsley et al., 2008) demonstrates a role of the calcineurin-NFAT-CDK4 pathway in maintaining hair follicle stem cell quiescence.

    View details for DOI 10.1016/j.stem.2008.01.008

    View details for Web of Science ID 000253301900002

    View details for PubMedID 18371427

  • Role of the basement membrane zone in skin development. journal of investigative dermatology Oro, A. E. 2008; 128 (E2): E11-2

    View details for DOI 10.1038/skinbio.6250016

    View details for PubMedID 21233816

  • The primary cilia, a 'Rab-id' transit system for hedgehog signaling CURRENT OPINION IN CELL BIOLOGY Oro, A. E. 2007; 19 (6): 691-696

    Abstract

    Intense focus has been centered around how the primary cilia transduces the hedgehog (Hh) signal from smoothened (Smo) to the Gli transcription factors. New data indicate that ligand and signaling lipids help regulate small GTPase-dependent accumulation and activity of signaling components.

    View details for DOI 10.1016/j.ceb.2007.10.008

    View details for Web of Science ID 000252143000014

    View details for PubMedID 18061425

  • Bone morphogenetic protein antagonist gremlin 1 is widely expressed by cancer-associated stromal cells and can promote tumor cell proliferation PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Sneddon, J. B., Zhen, H. H., Montgomery, K., van de Rijn, M., Tward, A. D., West, R., Gladstone, H., Chang, H. Y., Morganroth, G. S., Oro, A. E., Brown, P. O. 2006; 103 (40): 14842-14847

    Abstract

    Although tissue microenvironments play critical roles in epithelial development and tumorigenesis, the factors mediating these effects are poorly understood. In this work, we used a genomic approach to identify factors produced by cells in the microenvironment of basal cell carcinoma (BCC) of the skin, one of the most common human cancers. The global gene expression programs of stromal cell cultures derived from human BCCs showed consistent, systematic differences from those derived from nontumor skin. The gene most consistently expressed at a higher level in BCC tumor stromal cells compared with those from nontumor skin was GREMLIN 1, which encodes a secreted antagonist of the bone morphogenetic protein (BMP) pathway. BMPs and their antagonists are known to play a crucial role in stem and progenitor cell biology as regulators of the balance between expansion and differentiation. Consistent with the hypothesis that BMP antagonists might have a similar role in cancer, we found GREMLIN 1 expression in the stroma of human BCC tumors but not in normal skin in vivo. Furthermore, BMP 2 and 4 are expressed by BCC cells. Ex vivo, BMP inhibits, and Gremlin 1 promotes, proliferation of cultured BCC cells. We further found that GREMLIN 1 is expressed by stromal cells in many carcinomas but not in the corresponding normal tissue counterparts that we examined. Our data suggest that BMP antagonists may be important constituents of tumor stroma, providing a favorable microenvironment for cancer cell survival and expansion in many cancers.

    View details for DOI 10.1073/pnas.0606857103

    View details for Web of Science ID 000241069300037

    View details for PubMedID 17003113

  • Dual degradation signals control Gli protein stability and tumor formation GENES & DEVELOPMENT Huntzicker, E. G., Estay, I. S., Zhen, H., Lokteva, L. A., Jackson, P. K., Oro, A. E. 2006; 20 (3): 276-281

    Abstract

    Regulated protein destruction controls many key cellular processes with aberrant regulation increasingly found during carcinogenesis. Gli proteins mediate the transcriptional effects of the Sonic hedgehog pathway, which is implicated in up to 25% of human tumors. Here we show that Gli is rapidly destroyed by the proteasome and that mouse basal cell carcinoma induction correlates with Gli protein accumulation. We identify two independent destruction signals in Gli1, D(N) and D(C), and show that removal of these signals stabilizes Gli1 protein and rapidly accelerates tumor formation in transgenic animals. These data argue that control of Gli protein accumulation underlies tumorigenesis and suggest a new avenue for antitumor therapy.

    View details for DOI 10.1101/gad.1380906

    View details for Web of Science ID 000235267000002

    View details for PubMedID 16421275

  • Mammalian variations on a theme: a Smo and Sufu surprise DEVELOPMENTAL CELL Oro, A. E. 2006; 10 (2): 156-158

    Abstract

    Hedgehog signaling plays a critical role during development and tumorigenesis. While much mechanistic insight has come from pathway investigations in the fruit fly, recent studies suggest a distinct mammalian strategy for signaling from Smoothened to Gli through the novel protein Suppressor of Fused that may have therapeutic implications.

    View details for DOI 10.1016/j.devcel.2006.01.006

    View details for Web of Science ID 000235480500004

    View details for PubMedID 16459294

  • Conditional telomerase induction causes proliferation of hair follicle stem cells NATURE Sarin, K. Y., Cheung, P., Gilison, D., Lee, E., Tennen, R. I., Wang, E., Artandi, M. K., Oro, A. E., Artandi, S. E. 2005; 436 (7053): 1048-1052

    Abstract

    TERT, the protein component of telomerase, serves to maintain telomere function through the de novo addition of telomere repeats to chromosome ends, and is reactivated in 90% of human cancers. In normal tissues, TERT is expressed in stem cells and in progenitor cells, but its role in these compartments is not fully understood. Here we show that conditional transgenic induction of TERT in mouse skin epithelium causes a rapid transition from telogen (the resting phase of the hair follicle cycle) to anagen (the active phase), thereby facilitating robust hair growth. TERT overexpression promotes this developmental transition by causing proliferation of quiescent, multipotent stem cells in the hair follicle bulge region. This new function for TERT does not require the telomerase RNA component, which encodes the template for telomere addition, and therefore operates through a mechanism independent of its activity in synthesizing telomere repeats. These data indicate that, in addition to its established role in extending telomeres, TERT can promote proliferation of resting stem cells through a non-canonical pathway.

    View details for DOI 10.1038/nature03836

    View details for Web of Science ID 000231263900057

    View details for PubMedID 16107853

  • Receptor tyrosine phosphatase-dependent cytoskeletal remodeling by the hedgehog-responsive gene MIM/BEG4 JOURNAL OF CELL BIOLOGY Gonzalez-Quevedo, R., Shoffer, M., Horng, L., Oro, A. E. 2005; 168 (3): 453-463

    Abstract

    During development, dynamic remodeling of the actin cytoskeleton allows the precise placement and morphology of tissues. Morphogens such as Sonic hedgehog (Shh) and local cues such as receptor protein tyrosine phosphatases (RPTPs) mediate this process, but how they regulate the cytoskeleton is poorly understood. We previously identified Basal cell carcinoma-enriched gene 4 (BEG4)/Missing in Metastasis (MIM), a Shh-inducible, Wiskott-Aldrich homology 2 domain-containing protein that potentiates Gli transcription (Callahan, C.A., T. Ofstad, L. Horng, J.K. Wang, H.H. Zhen, P.A. Coulombe, and A.E. Oro. 2004. Genes Dev. 18:2724-2729). Here, we show that endogenous MIM is induced in a patched1-dependent manner and regulates the actin cytoskeleton. MIM functions by bundling F-actin, a process that requires self-association but is independent of G-actin binding. Cytoskeletal remodeling requires an activation domain distinct from sequences required for bundling in vitro. This domain associates with RPTPdelta and, in turn, enhances RPTPdelta membrane localization. MIM-dependent cytoskeletal changes can be inhibited using a soluble RPTPdelta-D2 domain. Our data suggest that the hedgehog-responsive gene MIM cooperates with RPTP to induce cytoskeletal changes.

    View details for DOI 10.1083/jcb.200409078

    View details for Web of Science ID 000226925500011

    View details for PubMedID 15684034

  • MIM/BEG4, a Sonic hedgehog-responsive gene that potentiates Gli-dependent transcription GENES & DEVELOPMENT Callahan, C. A., Ofstad, T., Horng, L., Wang, J. K., Zhen, H. H., Coulombe, P. A., Oro, A. E. 2004; 18 (22): 2724-2729

    Abstract

    Sonic hedgehog (Shh) signaling plays a critical role during development and carcinogenesis. While Gli family members govern the transcriptional output of Shh signaling, little is known how Gli-mediated transcriptional activity is regulated. Here we identify the actin-binding protein Missing in Metastasis (MIM) as a new Shh-responsive gene. Together, Gli1 and MIM recapitulate Shh-mediated epidermal proliferation and invasion in regenerated human skin. MIM is part of a Gli/Suppressor of Fused complex and potentiates Gli-dependent transcription using domains distinct from those used for monomeric actin binding. These data define MIM as both a Shh-responsive gene and a new member of the pathway that modulates Gli responses during growth and tumorigenesis.

    View details for DOI 10.1101/gad.1221804

    View details for Web of Science ID 000225170900004

    View details for PubMedID 15545630

  • Laminin-10 is crucial for hair morphogenesis EMBO JOURNAL Li, J., Tzu, J., Chen, Y., Zhang, Y. P., Nguyen, N. T., Gao, J., Bradley, M., Keene, D. R., Oro, A. E., Miner, J. H., Marinkovich, M. P. 2003; 22 (10): 2400-2410

    Abstract

    The role of the extracellular matrix in cutaneous morphogenesis is poorly understood. Here, we describe the essential role of laminin-10 (alpha5beta1gamma1) in hair follicle development. Laminin-10 was present in the basement membrane of elongating hair germs, when other laminins were downregulated, suggesting a role for laminin-10 in hair development. Treatment of human scalp xenografts with antibodies to laminin-10, or its receptor beta1 integrin, produced alopecia. E16.5 Lama5 -/- mouse skin, lacking laminin-10, contained fewer hair germs compared with controls, and after transplantation, Lama5 -/- skin showed a failure of hair germ elongation followed by complete hair follicle regression. Lama5 -/- skin showed defective basement membrane assembly, without measurable increases in anoikis. Instead, Lama5 -/- skin showed decreased expression of early hair markers including sonic hedgehog and Gli1, implicating laminin-10 in developmental signaling. Intriguingly, treatment of Lama5 -/- skin with purified laminin-10 corrected basement membrane defects and restored hair follicle development. We conclude that laminin-10 is required for hair follicle development and report the first use of exogenous protein to correct a cutaneous developmental defect.

    View details for Web of Science ID 000182957100010

    View details for PubMedID 12743034

  • Hair cycle regulation of Hedgehog signal reception DEVELOPMENTAL BIOLOGY Oro, A. E., Higgins, K. 2003; 255 (2): 238-248

    Abstract

    Proper patterning of self-renewing organs, like the hair follicle, requires exquisite regulation of growth signals. Sonic hedgehog (Shh) signaling in skin controls the growth and morphogenesis of hair follicle epithelium in part through regulating the Gli transcription factors. While ectopic induction of Shh target genes leads to hair follicle tumors, such as basal cell carcinomas, how Shh signaling normally functions during the cyclic process of hair development is unknown. Here, we show that, during the hair cycle, Shh expression and the ability of skin cells to respond to Shh signaling is spatially and temporally regulated. Induction of Shh target genes normally occurs only in the anagen hair follicle in response to expression of Shh. However, in patched1 heterozygous mice, putative tumor precursors form with concomitant induction of Shh target gene transcription only during anagen in follicular and interfollicular keratinocytes. Ectopic production of Gli1 accumulates Gli protein and induces Shh target genes and epithelial tumors at anagen but not other stages, pointing to a restricted competence occurring at the level of Gli protein accumulation. Delivery and reception of growth signals among multipotent cells are restricted in time and space to facilitate cyclic pattern formation.

    View details for DOI 10.1016/S0012-1606(02)00042-8

    View details for Web of Science ID 000181998400005

    View details for PubMedID 12648487

  • Ultraviolet and ionizing radiation enhance the growth of BCCs and trichoblastomas in patched heterozygous knockout mice NATURE MEDICINE Aszterbaum, M., Epstein, J., Oro, A., Douglas, V., LeBoit, P. E., Scott, M. P., Epstein, E. H. 1999; 5 (11): 1285-1291

    Abstract

    Basal cell carcinomas, the commonest human skin cancers, consistently have abnormalities of the hedgehog signaling pathway and often have PTCH gene mutations. We report here that Ptch+/- mice develop primordial follicular neoplasms resembling human trichoblastomas, and that exposure to ultraviolet radiation or ionizing radiation results in an increase in the number and size of these tumors and a shift in their histologic features so that they more closely resemble human basal cell carcinoma. The mouse basal cell carcinomas and trichoblastoma-like tumors resemble human basal cell carcinomas in their loss of normal hemidesmosomal components, presence of p53 mutations, frequent loss of the normal remaining Ptch allele, and activation of hedgehog target gene transcription. The Ptch mutant mice provide the first mouse model, to our knowledge, of ultraviolet and ionizing radiation-induced basal cell carcinoma-like tumors, and also demonstrate that Ptch inactivation and hedgehog target gene activation are essential for basal cell carcinoma tumorigenesis.

    View details for Web of Science ID 000086550600039

    View details for PubMedID 10545995

  • MOLECULAR ANALYSIS OF THE INHERITANCE AND STABILITY OF THE MITOCHONDRIAL GENOME OF AN INBRED LINE OF MAIZE THEORETICAL AND APPLIED GENETICS Oro, A. E., Newton, K. J., Walbot, V. 1985; 70 (3): 287-293