Boards, Advisory Committees, Professional Organizations

  • Associate Member, AACR - American Association for Cancer Research (2008 - Present)
  • Postdoctoral Member, SID - Society for Investigative Dermatology (2014 - Present)
  • Postdoctoral Member, ASCB - American Society for Cellular Biology (2012 - Present)
  • Postdoctoral Member, Oxbridge Biotech Roundtable - Bay Area Chapter (2012 - Present)
  • Predoctoral Member, CCTSI - Colorado Clinical and Translational Sciences Institute (2009 - 2012)
  • Predoctoral Advisor, Univ of Colorado, Anschutz Medical Campus - Graduate School Dean Search Committee (2011 - 2011)

Professional Education

  • Postdoctoral Training, Stanford Dermatology, Focus: Epithelial tumor resistance (2012 - )
  • Doctor of Philosophy, University of Colorado Denver (2012)
  • Bachelor of Science, California State University, Chico (2006)

Stanford Advisors

Current Research and Scholarly Interests

My immediate research aim is to determine the molecular basis for secondary resistance in basal cell carcinoma (BCC). Working with the Oro laboratory, we have made significant progress toward identifying factors that play a role in resistant BCCs. Using bioinformatic and functional cell biology approaches, we have identified novel drivers of BCC tumor resistance. My current focus is to determine the tumorigenic potential for putative drivers of resistance by developing reliable in vitro and in vivo functional assays.

All Publications

  • Smoothened variants explain the majority of drug resistance in Basal cell carcinoma. Cancer cell Atwood, S. X., Sarin, K. Y., Whitson, R. J., Li, J. R., Kim, G., Rezaee, M., Ally, M. S., Kim, J., Yao, C., Chang, A. L., Oro, A. E., Tang, J. Y. 2015; 27 (3): 342-353


    Advanced basal cell carcinomas (BCCs) frequently acquire resistance to Smoothened (SMO) inhibitors through unknown mechanisms. Here we identify SMO mutations in 50% (22 of 44) of resistant BCCs and show that these mutations maintain Hedgehog signaling in the presence of SMO inhibitors. Alterations include four ligand binding pocket mutations defining sites of inhibitor binding and four variants conferring constitutive activity and inhibitor resistance, illuminating pivotal residues that ensure receptor autoinhibition. In the presence of a SMO inhibitor, tumor cells containing either class of SMO mutants effectively outcompete cells containing the wild-type SMO. Finally, we show that both classes of SMO variants respond to aPKC-ι/λ or GLI2 inhibitors that operate downstream of SMO, setting the stage for the clinical use of GLI antagonists.

    View details for DOI 10.1016/j.ccell.2015.02.002

    View details for PubMedID 25759020

  • Epigenetic targeting of Hedgehog pathway transcriptional output through BET bromodomain inhibition NATURE MEDICINE Tang, Y., Gholamin, S., Schubert, S., Willardson, M. I., Lee, A., Bandopadhayay, P., Bergthold, G., Masoud, S., Nguyen, B., Vue, N., Balansay, B., Yu, F., Oh, S., Woo, P., Chen, S., Ponnuswami, A., Monje, M., Atwood, S. X., Whitson, R. J., Mitra, S., Cheshier, S. H., Qi, J., Beroukhim, R., Tang, J. Y., Wechsler-Reya, R., Oro, A. E., Link, B. A., Bradner, J. E., Cho, Y. 2014; 20 (7): 732-740


    Hedgehog signaling drives oncogenesis in several cancers, and strategies targeting this pathway have been developed, most notably through inhibition of Smoothened (SMO). However, resistance to Smoothened inhibitors occurs by genetic changes of Smoothened or other downstream Hedgehog components. Here we overcome these resistance mechanisms by modulating GLI transcription through inhibition of bromo and extra C-terminal (BET) bromodomain proteins. We show that BRD4 and other BET bromodomain proteins regulate GLI transcription downstream of SMO and suppressor of fused (SUFU), and chromatin immunoprecipitation studies reveal that BRD4 directly occupies GLI1 and GLI2 promoters, with a substantial decrease in engagement of these sites after treatment with JQ1, a small-molecule inhibitor targeting BRD4. Globally, genes associated with medulloblastoma-specific GLI1 binding sites are downregulated in response to JQ1 treatment, supporting direct regulation of GLI activity by BRD4. Notably, patient- and GEMM (genetically engineered mouse model)-derived Hedgehog-driven tumors (basal cell carcinoma, medulloblastoma and atypical teratoid rhabdoid tumor) respond to JQ1 even when harboring genetic lesions rendering them resistant to Smoothened antagonists. Altogether, our results reveal BET proteins as critical regulators of Hedgehog pathway transcriptional output and nominate BET bromodomain inhibitors as a strategy for treating Hedgehog-driven tumors with emerged or a priori resistance to Smoothened antagonists.

    View details for Web of Science ID 000338689500015

  • Advanced treatment for basal cell carcinomas. Cold Spring Harbor perspectives in medicine Atwood, S. X., Whitson, R. J., Oro, A. E. 2014; 4 (7)


    Basal cell carcinomas (BCCs) are very common epithelial cancers that depend on the Hedgehog pathway for tumor growth. Traditional therapies such as surgical excision are effective for most patients with sporadic BCC; however, better treatment options are needed for cosmetically sensitive or advanced and metastatic BCC. The first approved Hedgehog antagonist targeting the membrane receptor Smoothened, vismodegib, shows remarkable effectiveness on both syndromic and nonsyndromic BCCs. However, drug-resistant tumors frequently develop, illustrating the need for the development of next-generation Hedgehog antagonists targeting pathway components downstream from Smoothened. In this article, we will summarize available BCC treatment options and discuss the development of next-generation antagonists.

    View details for DOI 10.1101/cshperspect.a013581

    View details for PubMedID 24985127

  • Epigenetic targeting of hedgehog pathway transcriptional output. Neuro-oncology Cho, Y. J., Tang, Y., Schubert, S., Willardson, M., Bandopadhayay, P., Bergthold, G., Nguyen, B., Masoud, S., Vue, N., Balansay, B., Gholamin, S., Cheshier, S. H., Atwood, S. X., Whitson, R. J., Lee, A., Tang, J. Y., Qi, J., Beroukhim, R., Wechsler-Reya, R., Oro, A. E., Link, B., Bradner, J. E., Cho, Y. J. 2014; 16 Suppl 3: iii25


    (blind field)We used ligand and genetic activation of the Hedgehog pathway to study the effects of BET bromodomain inhibition on Hedgehog pathway transcriptional output. Furthermore, we studied the in vitro and in vivo efficacy of BET bromodomain inhibitors using tumor cells generated from genetically engineered mouse (GEM) and patient derived xenograft models of Hedgehog driven tumors, including a panel of tumors resistant to the current FDA-approved Smoothened antagonists.We show that knockdown of BRD4 or treatment with the BET bromodomain inhibitor, JQ1, dramatically inhibits transcription of GLI1, GLI2 and other Hedgehog target genes upon ligand-mediated or genetic activation of the Hedgehog pathway. We confirm the inhibitory effect of JQ1 occurs downstream of SMO and SUFU and verify by chromatin immunoprecipitation that BRD4 directly occupies the GLI1 and GLI2 promoters with a substantial decrease in the engagement of these genomic sites upon treatment with JQ1. We observe a corresponding downregulation of genes associated with medulloblastoma-specific GLI1 binding sites upon exposure to JQ1, confirming the direct regulation of GLI1 by BET bromodomain proteins. Finally, in patient- and GEM-derived cells of Hedgehog-driven cancer (basal cell carcinoma, medulloblastoma and atypical teratoid/rhabdoid tumor), we show that JQ1 decreases Hh pathway output and proliferation, even in cells resistant to Smoothened inhibitors.These results expand the role of BET bromodomain inhibitors to targeting Hedgehog-driven cancers and highlight a strategy that overcomes the limitation of Hedgehog pathway inhibitors currently in clinical use.Pediatrics.

    View details for DOI 10.1093/neuonc/nou208.9

    View details for PubMedID 25165259

  • Reduced expression of GDF-15 is associated with atrophic inflammatory lesions of the prostate. The Prostate Lambert, J. R., Whitson, R. J., Iczkowski, K. A., La Rosa, F. G., Smith, M. L., Wilson, R. S., Smith, E. E., Torkko, K. C., Gari, H. H., Lucia, M. S. 2014


    Accumulating evidence suggests that chronic prostatic inflammation may lead to prostate cancer development. Growth differentiation factor-15 (GDF-15) is highly expressed in the prostate and has been associated with inflammation and tumorigenesis.To examine the relationship between GDF-15 and prostatic inflammation, GDF-15 expression was measured by immunohistochemical (IHC) staining in human prostatectomy specimens containing inflammation. The relationship between GDF-15 and specific inflammatory cells was determined using non-biased computer image analysis. To provide insight into a potential suppressive role for GDF-15 in inflammation, activation of inflammatory mediator nuclear factor of kappa B (NFκB) was measured in PC3 cells.GDF-15 expression in luminal epithelial cells was decreased with increasing inflammation severity, suggesting an inverse association between GDF-15 and inflammation. Quantification of IHC staining by image analysis for GDF-15 and inflammatory cell markers revealed an inverse correlation between GDF-15 and CD3+, CD4+, CD8+, CD68+, and inos+ leukocytes. GDF-15 suppressed NFκB activity in luciferase reporter assays. Expression of the NFκB target, interleukin 8 (IL-8), was downregulated by GDF-15.The inverse relationship between GDF-15 and inflammation demonstrates a novel expression pattern for GDF-15 in the human prostate and suppression of NFκB activity may shed light on a potential mechanism for this inverse correlation. Prostate © 2014 Wiley Periodicals, Inc.

    View details for DOI 10.1002/pros.22911

    View details for PubMedID 25327758

  • Growth differentiation factor-15 (GDF-15) suppresses in vitro angiogenesis through a novel interaction with connective tissue growth factor (CCN2) JOURNAL OF CELLULAR BIOCHEMISTRY Whitson, R. J., Lucia, M. S., Lambert, J. R. 2013; 114 (6): 1424-1433


    Growth differentiation factor-15 (GDF-15) and the CCN family member, connective tissue growth factor (CCN2), are associated with cardiac disease, inflammation, and cancer. The precise role and signaling mechanism for these factors in normal and diseased tissues remains elusive. Here we demonstrate an interaction between GDF-15 and CCN2 using yeast two-hybrid assays and have mapped the domain of interaction to the von Willebrand factor type C domain of CCN2. Biochemical pull down assays using secreted GDF-15 and His-tagged CCN2 produced in PC-3 prostate cancer cells confirmed a direct interaction between these proteins. To investigate the functional consequences of this interaction, in vitro angiogenesis assays were performed. We demonstrate that GDF-15 blocks CCN2-mediated tube formation in human umbilical vein endothelial (HUVEC) cells. To examine the molecular mechanism whereby GDF-15 inhibits CCN2-mediated angiogenesis, activation of αV β3 integrins and focal adhesion kinase (FAK) was examined. CCN2-mediated FAK activation was inhibited by GDF-15 and was accompanied by a decrease in αV β3 integrin clustering in HUVEC cells. These results demonstrate, for the first time, a novel signaling pathway for GDF-15 through interaction with the matricellular signaling molecule CCN2. Furthermore, antagonism of CCN2 mediated angiogenesis by GDF-15 may provide insight into the functional role of GDF-15 in disease states.

    View details for DOI 10.1002/jcb.24484

    View details for Web of Science ID 000317864800022

    View details for PubMedID 23280549

  • "Patch"ing up our tumor signaling knowledge. journal of investigative dermatology Atwood, S. X., Whitson, R. J., Oro, A. E. 2013; 133 (5): 1131-1133


    The tumor suppressor Patched1 (Ptch1) possesses well-described roles in regulating sonic hedgehog (SHH) signaling in the skin and preventing the formation of basal cell carcinomas (BCCs). In this issue, Kang et al. extend their previous work to show that a naturally occurring allele of Ptch1 found in FVB mice promotes early squamous cell carcinoma (SCC) growth without aberrant activation of the SHH pathway. The study reveals new roles for Ptch1 that lie at the nexus between BCC and SCC formation.

    View details for DOI 10.1038/jid.2012.506

    View details for PubMedID 23594533

  • Prostate-derived factor/macrophage inhibitory cytokine-1/nonsteroidal anti-inflammatory drug activated gene: A mediator of prostatic inflammation AACR Special Conference on Advances in Prostate Cancer Research Whitson, R. J., Genova, E., Torkko, K., La Rosa, F. G., Kelly, J., Wilson, S., Lambert, J. R., Lucia, M. S. 2012

    View details for DOI 10.1158/15387445