Paradoxical Role for Wild-Type p53 in Driving Therapy Resistance in Melanoma.

Metastatic melanoma is an aggressive disease, despite recent improvements in therapy. Eradicating all melanoma cells even in drug-sensitive tumors is unsuccessful in patients because a subset of cells can transition to a slow-cycling state, rendering them resistant to most targeted therapy. It is still unclear what pathways define these subpopulations and promote this resistant phenotype. In the current study, we show that Wnt5A, a non-canonical Wnt ligand that drives a metastatic, therapy-resistant phenotype, stabilizes the half-life of p53 and uses p53 to initiate a slow-cycling state following stress (DNA damage, targeted therapy, and aging). Inhibiting p53 blocks the slow-cycling phenotype and sensitizes melanoma cells to BRAF/MEK inhibition. In vivo, this can be accomplished with a single dose of p53 inhibitor at the commencement of BRAF/MEK inhibitor therapy. These data suggest that taking the paradoxical approach of inhibiting rather than activating wild-type p53 may sensitize previously resistant metastatic melanoma cells to therapy.

Merkel Cell Hyperplasia Versus Intraepidermal Merkel Cell Carcinoma: A Comparative Study of 2 Cases.

ABSTRACT: Intraepidermal Merkel cell hyperplasia and Merkel cell carcinoma represent 2 histologically similar-appearing diagnoses with significant differences regarding prognosis and management. We present 1 case of each diagnosis to highlight characteristic histopathologic and immunohistochemical features. Our case of Merkel cell hyperplasia was identified by its small intraepidermal nest of monomorphic cells without atypia or mitoses, which demonstrated cytoplasmic, rather than perinuclear dot, patterning on CK20 staining. This can be contrasted with our case of intraepidermal Merkel cell carcinoma, which, despite a lack of dermal extension, demonstrated large nests of pleomorphic cells with frequent mitoses and apoptoses. The diagnosis was further confirmed by immunohistochemistry because CK20 staining showed classic perinuclear dot patterning. By presenting both diagnoses in parallel, this comparison aims to underscore crucial histopathologic and immunohistochemical similarities and differences.

sFRP2 in the aged microenvironment drives melanoma metastasis and therapy resistance.

Cancer is a disease of ageing. Clinically, aged cancer patients tend to have a poorer prognosis than young. This may be due to accumulated cellular damage, decreases in adaptive immunity, and chronic inflammation. However, the effects of the aged microenvironment on tumour progression have been largely unexplored. Since dermal fibroblasts can have profound impacts on melanoma progression, we examined whether age-related changes in dermal fibroblasts could drive melanoma metastasis and response to targeted therapy. Here we find that aged fibroblasts secrete a Wnt antagonist, sFRP2, which activates a multi-step signalling cascade in melanoma cells that results in a decrease in ß-catenin and microphthalmia-associated transcription factor (MITF), and ultimately the loss of a key redox effector, APE1. Loss of APE1 attenuates the response of melanoma cells to DNA damage induced by reactive oxygen species, rendering the cells more resistant to targeted therapy (vemurafenib). Age-related increases in sFRP2 also augment both angiogenesis and metastasis of melanoma cells. These data provide an integrated view of how fibroblasts in the aged microenvironment contribute to tumour progression, offering new possibilities for the design of therapy for the elderly.

Sarcomatoid Dedifferentiated Melanoma: The Diagnostic Role of Next-Generation Sequencing.

ABSTRACT: Sarcomatoid dedifferentiated melanoma (SDDM) represents a diagnostic challenge as this cutaneous spindle cell melanoma lacks expression of classic melanocytic markers including S100, SOX10, Melan-A, HMB45, and MITF. The expression of the emerging melanoma marker preferentially expressed antigen in melanoma (PRAME) in SDDM is largely unknown. In this article, a case of SDDM arising in association with a nodular melanoma is highlighted. A 65-year-old man presented with a several week history of an ulcerated lesion on the right medial knee. A shave biopsy of the lesion revealed a biphasic neoplasm, which consisted of a centrally located poorly differentiated spindle cell component and an adjacent nodular component consisting of atypical melanocytes arranged in nests and fascicles. While the nodular component stained for S100, SOX10, and Melan-A, the spindle cell component failed to stain for these conventional melanocytic markers, only staining diffusely for CD10 and faintly for CD68. Both components stained for PRAME diffusely albeit less intensely within the spindle cell component. Next-generation DNA sequencing assay of the microdissected biphasic components revealed a shared mutation of NRAS. The results of the PRAME immunohistochemical stain and next-generation DNA sequencing assay facilitated in establishing the diagnosis of SDDM in association with nodular melanoma.

Plexiform fibrohistiocytic tumor on the chest of a 5-year-old child and review of the literature.

Plexiform fibrohistiocytic tumor (PFT) is a rare neoplasm of mesenchymal origin that can be identified by its propensity for children and adolescents combined with a characteristic histologic arrangement of histiocytes and osteoclast-like giant cells whorled within tumor islands. A 5-year-old female presented with a raised, intermittently tender, and slowly enlarging tumor on her chest, which was histologically confirmed to be a PFT. We present this case along with a comprehensive review of PFT cases reported in the literature to describe the demographic, histologic, and rarely metastatic behavior of this entity. It is important to include PFT on the differential diagnosis of an enlarging tumor in the pediatric population.

Comparative secretome analysis of epithelial and mesenchymal subpopulations of head and neck squamous cell carcinoma identifies S100A4 as a potential therapeutic target.

Epithelial-mesenchymal transition (EMT) is a key contributor in tumor progression and metastasis. EMT produces cellular heterogeneity within head and neck squamous cell carcinomas (HNSCC) by creating a phenotypically distinct mesenchymal subpopulation that is resistant to conventional therapies. In this study, we systematically characterized differences in the secretomes of E-cadherin high epithelial-like and E-cadherin low mesenchymal-like subpopulations using unbiased and targeted proteomics. A total 1765 proteins showed significant changes with 177 elevated in the epithelial subpopulation and 173 elevated in the mesenchymal cells. Key nodes in affected networks included NFκB, Akt, and ERK, and most implicated cellular components involved various aspects of the extracellular matrix. In particular, large changes were observed in multiple collagens with most affected collagens at much higher abundance levels in the mesenchymal subpopulation. These cells also exhibited a secretome profile resembling that of cancer-associated fibroblastic cells (CAF). S100A4, a commonly used marker for cancer-associated fibroblastic cells, was elevated more than 20-fold in the mesenchymal cells and this increase was further verified at the transcriptome level. S100A4 is a known mediator of EMT, leading to metastasis and EMT has been proposed as a potential source of cancer-associated fibroblastic cells in solid tumors. S100A4 knockdown by small interfering RNA led to decreased expression, secretion and activity of matrix metalloproteinase 2, as verified by quantitative PCR, multiple reaction monitoring and zymography analyses, and reduced invasion in collagen-embedded spheroids. Further confirmation in three-dimensional organotypic reconstructs showed less invasion and advanced differentiation in the S100A4 RNA interference samples. Orthotopic metastasis model, developed to validate the findings in vivo, demonstrated a decrease in spontaneous metastasis and augmented differentiation in the primary tumor in siS100A4 xenografts. These results demonstrate the value of secretome profiling to evaluate phenotypic conversion and identify potential novel therapeutic targets such as S100A4.

Medical spa facilities and nonphysician operators in aesthetics.

Consumer interest in aesthetic procedures continues to grow. Through savvy marketing, affordable pricing, and minimal wait times, medical spas have grown in number to where they now outnumber physician-based cosmetic practices in 73% of major U.S. cities. To staff these facilities, owners frequently turn to nonphysician operators who have variable levels of training in dermatology and cosmetics. There has been a lack of uniform standardization of training and oversight, which may contribute to adverse events, such as burns, pigmentary alterations, and scarring. As the market for noninvasive and minimally invasive cosmetic procedures continues to grow, physicians should be informed about the current cosmetic landscape in which they practice to improve patient awareness, education, and safety.

Rise in male cosmetic procedures in dermatology: A 4.5-year clinical evaluation.

This commentary examines the growing popularity of cosmetic procedures in men. With the recent increase in aesthetic procedures across the nation, it is important for physicians to understand trends as they evolve, which can help to optimize clinical training, business operations, and practice management. Although the popularity of cosmetic procedures in men has increased, available data on consumer behavior is limited. Our data fills this gap by examining the patterns of cosmetic procedures in men. Due to hormonal and anatomic differences, the pathophysiology of cutaneous aging differs between sexes, which can have significant implications for treatment. Our data demonstrates a positive trend in recent years and also breaks it down by individual procedures.

Comparison of injectable filler locations in men and women: An age-matched case analysis.

In recent years, the popularity of fillers has risen significantly. Traditionally, women have undergone the vast majority of cosmetic procedures, but men have steadily shown increasing interest. Recently, significant research has been dedicated to understanding the anatomic differences between male and female facial structures and their clinical aesthetic implications, especially for filler placement. In order to compare actual treatment data to evidence these discussions, we randomly selected 100 cases each of men and women, who were matched for age, and documented their filler placement locations. Facial heat maps were constructed to provide readers with visual evidence. Injections for male cheeks were more inferiomedial, while female cheeks were more superolateral. Men had more jawline fillers, while women had more lip and perioral fillers. Our study builds upon gender-specific considerations. It is important for physicians to be knowledgeable regarding the unique approaches to fillers in men and women in order to deliver more effective, tailored, and high-quality care.

Safety of combining cosmetic injectables with radiofrequency microneedling: A 4.5-year review.

Pairing energy-based treatments, including radiofrequency microneedling, with either injectable neuromodulators or soft-tissue fillers can be an effective therapy for facial rejuvenation. However, there remains concerns by some physicians that this combination may add new risks for adverse events. Theoretical risks of combining energy-based treatment with neuromodulator injections include unintentional spread, which may result in eyelid ptosis and asymmetry. Potential risks with soft-tissue fillers include unexpected loss of filler volume, necrosis, burn, and product migration. In order to shed more light on this topic, we performed a retrospective chart review of single-session facial treatments with radiofrequency microneedling and cosmetic injectables over a 4.5 year period. We found no documented adverse events recorded related to combination treatment. This is important information that adds to the patient safety literature.

Wnt5A promotes an adaptive, senescent-like stress response, while continuing to drive invasion in melanoma cells.

We have previously shown that Wnt5A drives invasion in melanoma. We have also shown that Wnt5A promotes resistance to therapy designed to target the BRAF(V600E) mutation in melanoma. Here, we show that melanomas characterized by high levels of Wnt5A respond to therapeutic stress by increasing p21 and expressing classical markers of senescence, including positivity for senescence-associated ß-galactosidase (SA-ß-gal), senescence-associated heterochromatic foci (SAHF), H3K9Me chromatin marks, and PML bodies. We find that despite this, these cells retain their ability to migrate and invade. Further, despite the expression of classic markers of senescence such as SA-ß-gal and SAHF, these Wnt5A-high cells are able to colonize the lungs in in vivo tail vein colony-forming assays. This clearly underscores the fact that these markers do not indicate true senescence in these cells, but instead an adaptive stress response that allows the cells to evade therapy and invade. Notably, silencing Wnt5A reduces expression of these markers and decreases invasiveness. The combined data point to Wnt5A as a master regulator of an adaptive stress response in melanoma, which may contribute to therapy resistance.

Hypoxia induces phenotypic plasticity and therapy resistance in melanoma via the tyrosine kinase receptors ROR1 and ROR2.

UNLABELLED: An emerging concept in melanoma biology is that of dynamic, adaptive phenotype switching, where cells switch from a highly proliferative, poorly invasive phenotype to a highly invasive, less proliferative one. This switch may hold significant implications not just for metastasis, but also for therapy resistance. We demonstrate that phenotype switching and subsequent resistance can be guided by changes in expression of receptors involved in the noncanonical Wnt5A signaling pathway, ROR1 and ROR2. ROR1 and ROR2 are inversely expressed in melanomas and negatively regulate each other. Furthermore, hypoxia initiates a shift of ROR1-positive melanomas to a more invasive, ROR2-positive phenotype. Notably, this receptor switch induces a 10-fold decrease in sensitivity to BRAF inhibitors. In patients with melanoma treated with the BRAF inhibitor vemurafenib, Wnt5A expression correlates with clinical response and therapy resistance. These data highlight the fact that mechanisms that guide metastatic progression may be linked to those that mediate therapy resistance. SIGNIFICANCE: These data show for the fi rst time that a single signaling pathway, the Wnt signaling pathway, can effectively guide the phenotypic plasticity of tumor cells, when primed to do so by a hypoxic microenvironment. Importantly, this increased Wnt5A signaling can give rise to a subpopulation of highly invasive cells that are intrinsically less sensitive to novel therapies for melanoma, and targeting the Wnt5A/ROR2 axis could improve the efficacy and duration of response for patients with melanoma on vemurafenib.