Three-dimensional (3D) printing is an emerging technology capable of readily producing accurate anatomical models, however, evidence for the use of 3D prints in medical education remains limited. A study was performed to assess their effectiveness against cadaveric materials for learning external cardiac anatomy. A double blind randomized controlled trial was undertaken on undergraduate medical students without prior formal cardiac anatomy teaching. Following a pre-test examining baseline external cardiac anatomy knowledge, participants were randomly assigned to three groups who underwent self-directed learning sessions using either cadaveric materials, 3D prints, or a combination of cadaveric materials/3D prints (combined materials). Participants were then subjected to a post-test written by a third party. Fifty-two participants completed the trial; 18 using cadaveric materials, 16 using 3D models, and 18 using combined materials. Age and time since completion of high school were equally distributed between groups. Pre-test scores were not significantly different (P = 0.231), however, post-test scores were significantly higher for 3D prints group compared to the cadaveric materials or combined materials groups (mean of 60.83% vs. 44.81% and 44.62%, P = 0.010, adjusted P = 0.012). A significant improvement in test scores was detected for the 3D prints group (P = 0.003) but not for the other two groups. The finding of this pilot study suggests that use of 3D prints do not disadvantage students relative to cadaveric materials; maximally, results suggest that 3D may confer certain benefits to anatomy learning and supports their use and ongoing evaluation as supplements to cadaver-based curriculums. Anat Sci Educ 9: 213-221. © 2015 American Association of Anatomists.

DW (1991) Deletion of steroid 5 alpha-reductase 2 gene in male pseudohermaphroditism. Nature 354:159-61 Andersson S, Russell DW (1990) Structural and biochemical properties of cloned and expressed human and rat steroid 5 alpha-reductases. Proc Natl Acad Sci USA 87:3640-4 Chen W, Thiboutot D, Zouboulis CC (2002) Cutaneous androgen metabolism: basic research and clinical perspectives. J Invest Dermatol 119:992-1007 Chen W, Tsai SJ, Tsai JC, Zouboulis CC (2009) Testosterone synthesized in cultured human SZ95 sebocytes mainly derives from dehydroepiandrosterone. Br J Dermatol (in press) Chen W, Zouboulis CC, Fritsch M, Blume-Peytavi U, Kodelja V, Goerdt S et al. (1998) Evidence of heterogeneity and quantitative differences of the type 1 5alpha-reductase expression in cultured human skin cells-evidence of its presence in melanocytes. J Invest Dermatol 110:84-9 Deplewski D, Rosenfield RL (2000) Role of hormones in pilosebaceous unit development. Endocr Rev 21:363-92 Dumont M, Luu-The V, Dupont E, Pelletier G, Labrie F (1992) Characterization, expression, and immunohistochemical localization of 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase in human skin.

In postnatal skin the transcription factor Sox2 is expressed in the dermal papilla (DP) of guard/awl/auchene hair follicles and by mechanosensory Merkel cells in the touch domes of guard hairs. To investigate the consequences of Sox2 ablation in skin we deleted Sox2 in DP cells via Blimp1Cre and in Merkel cells via K14Cre. Loss of Sox2 from the DP did not inhibit hair follicle morphogenesis or establishment of the dermis and hypodermis. However, Sox2 expression in the DP was necessary for postnatal maintenance of awl/auchene hair follicles. Deletion of Sox2 via K14Cre resulted in a decreased number of Merkel cells but had no effect on other epithelial compartments or on the dermis. The reduced number of Merkel cells did not affect the number or patterning of guard hairs, nerve density or the interaction of nerve cells with the touch domes. We conclude that Sox2 is a marker of two distinct lineages in the skin and regulates the number of differentiated cells in the case of the Merkel cell lineage and hair follicle type in the case of the DP.

New therapeutic strategies are needed to improve treatment of head and neck squamous cell carcinoma (HNSCC), an aggressive tumor with poor survival rates. FRMD4A is a human epidermal stem cell marker implicated previously in epithelial polarity that is upregulated in SCC cells. Here, we report that FRMD4A upregulation occurs in primary human HNSCCs where high expression levels correlate with increased risks of relapse. FRMD4A silencing decreased growth and metastasis of human SCC xenografts in skin and tongue, reduced SCC proliferation and intercellular adhesion, and stimulated caspase-3 activity and expression of terminal differentiation markers. Notably, FRMD4A attenuation caused nuclear accumulation of YAP, suggesting a potential role for FRMD4A in Hippo signaling. Treatment with the HSP90 inhibitor 17-DMAG or ligation of CD44 with hyaluronan caused nuclear depletion of FRMD4A, nuclear accumulation of YAP and reduced SCC growth and metastasis. Together, our findings suggest FRMD4A as a novel candidate therapeutic target in HNSCC based on the key role in metastatic growth we have identified. Cancer Res; 72(13); 3424-36. Ó2012 AACR.

SummaryMetastatic colonization of distant organs underpins the majority of human-cancer-related deaths, including deaths from head and neck squamous cell carcinoma (HNSCC). We report that miR-203, a miRNA that triggers differentiation in multilayered epithelia, inhibits multiple postextravasation events during HNSCC lung metastasis. Inducible reactivation of miR-203 in already established lung metastases reduces the overall metastatic burden. Using an integrated approach, we reveal that miR-203 inhibits metastasis independently of its effects on differentiation. In vivo genetic reconstitution experiments show that miR-203 inhibits lung metastasis by suppressing the prometastatic activities of three factors involved in cytoskeletal dynamics (LASP1), extracellular matrix remodeling (SPARC), and cell metabolism (NUAK1). Expression of miR-203 and its downstream effectors correlates with HNSCC overall survival outcomes, indicating the therapeutic potential of targeting this signaling axis.

Correct tissue architecture is essential for normal physiology, yet there have been few attempts to recreate tissues using micro-patterning. We have used polymer brush micro-engineering to generate a stratified micro-epidermis with fewer than 10 human keratinocytes. Epidermal stem cells are captured on 100 μm diameter circular collagen-coated disks. Within 24 h they assemble a stratified micro-tissue, in which differentiated cells have a central suprabasal location. For rings with a non-adhesive centre of up to 40 μm diameter, cell–cell and cell–matrix adhesive interactions together result in correct micro-epidermis assembly. Assembly requires actin polymerization, adherens junctions and desmosomes, but not myosin II-mediated contractility nor coordinated cell movement. Squamous cell carcinoma cells on micro-patterned rings exhibit disturbed architecture that correlates with the characteristics of the original tumours. The micro-epidermis we have generated provides a new platform for screening drugs that modulate tissue assembly, quantifying tissue stratification and investigating the properties of tumour cells.

We have previously described InvEE transgenic mice in which non-dividing, differentiating epidermal cells express oncogenically activated MAPK kinase 1 (MEK1). Skin wounding triggers tumour formation in InvEE mice via a mechanism that involves epidermal release of IL-1a and attraction of a pro-tumorigenic inflammatory infiltrate. To look for potential effects on the underlying connective tissue, we screened InvEE and wild-type epidermis for differential expression of cytokines and immune modulators. We identified a single protein, CD26 (dipeptidyl peptidase-4). CD26 serum levels were not increased in InvEE mice. In contrast, CD26 was upregulated in keratinocytes expressing mutant MEK1 and in the epithelial compartment of InvEE tumours, where it accumulated at cell-cell borders. CD26 expression was increased in dermal fibroblasts following skin wounding but was downregulated in tumour stroma. CD26 activity was stimulated by calcium-induced intercellular adhesion in keratinocytes, suggesting that the upregulation of CD26 in InvEE epidermis is due to expansion of the differentiated cell layers. IL-1a treatment of dermal fibroblasts stimulated CD26 activity, and therefore epidermal IL-1a release may contribute to the upregulation of CD26 expression in wounded dermis. Pharmacological blockade of CD26, via Sitagliptin, reduced growth of InvEE tumours, while combined inhibition of IL-1a and CD26 delayed tumour onset and reduced tumour incidence. Our results demonstrate that inappropriate activation of MEK1 in the epidermis leads to changes in dermal fibroblasts that, like the skin inflammatory infiltrate, contribute to tumour formation.

Oral squamous cell carcinoma (OSCC) is genetically highly heterogeneous, which contributes to the challenges of treatment. To create an in vitro model that accurately reflects this heterogeneity, we generated a panel of HPV-negative OSCC cell lines. By whole exome sequencing of the lines and matched patient blood samples, we demonstrate that the mutational spectrum of the lines is representative of primary OSCC in The Cancer Genome Atlas. We show that loss of function mutations in FAT1 (an atypical cadherin) and CASP8 (Caspase 8) frequently occur in the same tumour. OSCC cells with inactivating FAT1 mutations exhibited reduced intercellular adhesion. Knockdown of FAT1 and CASP8 individually or in combination in OSCC cells led to increased cell migration and clonal growth, resistance to Staurosporine-induced apoptosis and, in some cases, increased terminal differentiation. The OSCC lines thus represent a valuable resource for elucidating the impact of different mutations on tumour behaviour.