Alterations in the tissue microenvironment collaborate with cell autonomous genetic changes to contribute to neoplastic progression. The importance of the microenvironment in neoplastic progression is underscored by studies demonstrating that fibroblasts isolated from a tumor stimulate the growth of preneoplastic and neoplastic cells in xenograft models. Similarly, senescent fibroblasts promote preneoplastic cell growth in vitro and in vivo. Because senescent cells accumulate with age, their presence is hypothesized to facilitate preneoplastic cell growth and tumor formation in older individuals. To identify senescent stromal factors directly responsible for stimulating preneoplastic cell growth, we carried out whole genome transcriptional profiling and compared senescent fibroblasts to their younger counterparts. We identified osteopontin (OPN) as one of the most highly elevated transcripts in senescent fibroblasts. Importantly, reduction of OPN protein levels by RNAi did not impact senescence induction in fibroblasts; however, it dramatically reduced the growth-promoting activities of senescent fibroblasts in vitro and in vivo, demonstrating that OPN is necessary for paracrine stimulation of preneoplastic cell growth. In addition, we found that recombinant OPN was sufficient to stimulate preneoplastic cell growth. Finally, we demonstrate that OPN is expressed in senescent stroma within preneoplastic lesions that arise following DMBA/TPA treatment of mice, suggesting that stromal-derived OPN-mediated signaling events impact neoplastic progression.
Senescent stromal-derived osteopontin promotes preneoplastic cell growth.
No sample metadata fields
View SamplesWe utilized whole genome sequencing of mRNA (RNA-seq) to understand the extent to which the senescence-associated secretory phenotype is regulated by p38MAPK Overall design: Examination of replicates of young, senescent or p38MAPK-inhibited senescent BJ human foreskin fibroblasts.
p38MAPK plays a crucial role in stromal-mediated tumorigenesis.
No sample metadata fields
View SamplesVitiligo is an acquired depigmentation of the skin inducing a marked alteration of the quality of life of affected individuals. Halting the disease progression and repigmenting the lesional skin represent the two faces of the therapeutic challenge in vitiligo. So far, none of them has been successfully addressed. Oxidative stress and immune system in genetically predisposed individuaLesionalparticipate to the complex pathophysiology of vitiligo. We performed a transcriptome and proteomic analysis on lesional, perilesional and non-depigmented skin of vitiligo patients compared to matched skin controLesionalof healthy subjects. Our results show that the WNT pathway, implicated in melanocytes differentiation, was found to be altered in vitiligo skin. We demonstrated that the oxidative stress decreases WNT expression/activation in keratinocytes and in melanocytes. We developed an ex vivo skin model that remains functional up to 15 days. We then confirmed the decreased activation of the WNT pathway in human skin subjected to oxidative stress. Finally, using pharmacological agents that activate the WNT pathway, we treated the ex vivo depigmented skins from vitiligo patients and successfully induced the differentiation of resident stem celLesionalinto pre-melanocytes supporting further exploration of WNT activators to repigment vitiligo lesions.
Transcriptional Analysis of Vitiligo Skin Reveals the Alteration of WNT Pathway: A Promising Target for Repigmenting Vitiligo Patients.
Specimen part
View SamplesBackground: First- and third-generation retinoids are the main treatment in acne. Even though efficacious, they lack full selectivity for RAR expressed in the epidermis and infundibulum. Objectives: To characterize the in vitro metabolism and the pharmacology of the novel retinoid trifarotene. Methods: In vitro assays determined efficacy, potency and selectivity on RARs, as well as the activity on the expression of retinoid target genes in human keratinocytes and ex vivo cultured skin. In vivo studies investigated topical comedolytic, anti-inflammatory and depigmenting properties. The trifarotene-induced gene expression profile was investigated in non-lesional skin of acne patients and compared to ex vivo and in vivo models. Finally, the metabolic stability in human keratinocytes and hepatic microsomes was established. Results: Trifarotene is a selective RAR agonist with >20-fold selectivity over RAR and RAR. Trifarotene is active and stable in keratinocytes but rapidly metabolized by human hepatic microsomes, predicting improved safety. In vivo, trifarotene 0.01% applied topically is highly comedolytic and has antiinflammatory and antipigmenting properties. Gene expression studies indicated potent activation of known retinoid-modulated processes (epidermal differentiation, proliferation, stress response, RA metabolism) and novel pathways (proteolysis, transport/skin hydration, cell adhesion) in ex vivo and in vivo models, as well as in human skin after four weeks of topical application of trifarotene 0.005% cream. Conclusion: Based on its RAR selectivity, rapid degradation in human hepatic microsomes and pharmacological properties including potent modulation of epidermal processes, topical treatment with trifarotene is expected to provide strong efficacy combined with a favourable safety profile in acne and ichthyotic disorders.
Nonclinical and human pharmacology of the potent and selective topical retinoic acid receptor-γ agonist trifarotene.
Specimen part
View SamplesWe have shown that activin promoted skin tumorigenesis in mice induced by the human papilloma virus 8 oncogenes. Activin attracted blood monocytes to the skin as revealed by depletion of CCR2-positive monocytes. To determine if activin also altered the gene expression profile of these cells, we performed RNA-Sequencing of macrophages FACS-sorted from the pre-cancerous ear skin. We have found that activin induces a pro-migratiory, pro-angiogenic and pro-tumorigenic genes in skin macrophages in vivo. This largely contributes to the pro-tumorigenic function of activin, since macrophage depletion delayed spontaneous tumorigenesis in HPV8-transgenic mice by reducing keratinocyte proliferation and angiogenesis. Overall design: F4/80+CD11b+CD45+ cells were FACS-sorted from the pre-cancerous ear skin of wt/wt, HPV8/wt, wt/Act and HPV8/Act mice and their expression profile was analysed by RNA-Sequencing. Experiment was performed in triplicates, for each replicate ear skin of 3-6 mice of corresponding genotype was pooled.
Activin promotes skin carcinogenesis by attraction and reprogramming of macrophages.
Specimen part, Cell line, Subject
View Samples