Triple-negative breast cancers (TNBCs) account for a large proportion of breast cancer deaths, due to the high rate of recurrence from residual, resistant tumor cells. New treatments are needed, to bypass chemoresistance and improve survival. The WNT pathway, which is activated in TNBCs, has been identified as an attractive pathway for treatment targeting. We analyzed expression of the WNT coreceptors LRP5 and LRP6 in human breast cancer samples. As previously described, LRP6 was overexpressed in TNBCs. However, we also showed, for the first time, that LRP5 was overexpressed in TNBCs too. The knockdown of LRP5 or LRP6 decreased tumorigenesis in vitro and in vivo, identifying both receptors as potential treatment targets in TNBC. The apoptotic effect of LRP5 knockdown was more robust than that of LRP6 depletion. We analyzed and compared the transcriptomes of cells depleted of LRP5 or LRP6, to identify genes specifically deregulated by LRP5 potentially implicated in cell death. We identified serine/threonine kinase 40 (STK40) as one of two genes specifically downregulated soon after LRP5 depletion. STK40 was found to be overexpressed in TNBCs, relative to other breast cancer subtypes, and in various other tumor types. STK40 depletion decreased cell viability and colony formation, and induced the apoptosis of TNBC cells. In addition, STK40 knockdown impaired growth in an anchorage-independent manner in vitro and slowed tumor growth in vivo. These findings identify the largely uncharacterized putative protein kinase STK40 as a novel candidate treatment target for TNBC.

Fibroblasts are important players in regulating tissue homeostasis. In the dermis, they are involved in wound healing where they differentiate into contractile myofibroblasts leading to wound closure. In nonhealing chronic wounds, fibroblasts fail to undertake differentiation. We established and used a human ex vivo model of chronic wounds where fibroblasts can undergo normal myofibroblast differentiation, or take on a nondifferentiable pathological state. At the whole genome scale, we identified the genes that are differentially regulated in these two cell fates. By coupling the search of evolutionary conserved regulatory elements with global gene network expression changes, we identified transcription factors (TF) potentially involved in myofibroblast differentiation, and constructed a network of relationship between these key factors. Among these, we found that TCF4, SOX9, EGR2, and FOXS1 are major regulators of fibroblast to myofibroblast differentiation. Conversely, down-regulation of MEOX2, SIX2, and MAF causes reprogramming of fibroblasts to myofibroblasts even in absence of TGF-b, the natural inducer of myofibroblast differentiation. These results provide insight into the fibroblast differentiation program and reveal a TF network essential for cellular reprogramming. They could lead to the development of new therapeutics to treat fibroblast-related human pathologies.

Background: Skin aging is characterized by slacking and loss of density, especially under ultraviolet (UV) radiation exposure. Objective: To investigate the beneficial effects of a combination containing bakuchiol (BK) and vanilla tahitensis extract (VTE) to prevent skin photoaging in vitro and to improve clinical outcomes for naturally aged skin. Materials and Methods: Human dermal fibroblasts were treated with active compounds, exposed to an acute dose of UVA and analyzed by confocal microscopy: actin network for morphology, interleukin-8 (IL-8) for inflammation and p16 for senescence. Human skin was used to evaluate chronic UVA-induced glycosaminoglycan (GAG) loss and to assess the benefit of topical application of a BK+VTE serum (Alcian blue staining). An open-label clinical trial was conducted in women applying the serum twice daily for 56 days (n=43). Skin remodeling was assessed by FaceScan ®. Firmness was evaluated through Dynaskin ® and clinical scoring. Skin radiance was also rated on standardized full-face photographs. Results: UVA induced a significant increase in IL-8 and p16 expression and marked morphological changes in fibroblasts. Treatment with BK or VTE alone prevented both actin network alteration and IL-8 upregulation. Interestingly, BK+VTE demonstrated synergistic protection against IL-8 and p16 overexpression. Serum application prevented GAG loss at the dermo-epidermal junction and increased dermal GAG in UVA-exposed skin explants. In the clinical trial, face ptosis was reduced by 11% on average for 26 responsive subjects and up to 23%. Depth of skin deformation was also reduced by 24% on average for 30 responsive subjects and up to 30%. This firming effect was confirmed by clinical scoring. Radiance was significantly improved by 29% on average for 33 responsive subjects. The serum demonstrated good tolerance/safety. Conclusion: BK+VTE combination demonstrated anti-aging efficacy and might provide a substantial benefit in the daily care of naturally aged skin in women, through their synergistic effect on inflammaging and senescence.

Background A biological concentrate was produced from cultures of an Avène aquatic microflora isolate, namely Aquaphilus dolomiae. Some of the beneficial effects on diseased and damaged skin are thought to be due to the presence of this microorganism. Aims An extract of A. dolomiae (A. dolomiae extract‐G2, ADE‐G2) was evaluated for its wound‐healing effects using in vitro and ex vivo models of injured skin. Methods The effect of ADE‐G2 on the proliferation of fibroblasts, migration of keratinocytes and re‐epithelialization of ex vivo wounded skin explants was measured. Antimicrobial protection by ADE‐G2 was measured by analysing the gene expression of a panel of antimicrobial proteins (AMPs) in keratinocytes (RNASE7, S100A7, DEFB4A/B and DEFb103B), as well as the protein encoded by DEFB4A‐B (hBD2) in the medium. Results ADE‐G2 increased fibroblast proliferation and keratinocyte migration, as well as re‐epithelialization of wounded ex vivo skin. ADE‐G2 induced the expression of all AMP genes analysed in keratinocytes, as well as stimulated the release in to the medium of hBD2 peptide, encoded by DEFB4A/B. Conclusions We have shown the broad spectrum of the repairing properties of the A. dolomiae extract, ADE‐G2. These results support the use of ADE‐G2 as a promising component for use in formulations aimed at repairing skin, limiting wound superinfection and preventing complicated wounds.

No abstract

Objective We investigated the dermal bioavailability and antioxidative properties of a sunscreen formulation containing two antioxidants, oxothiazolidine (OTZ) and δ‐tocopheryl glucoside (DTG). OTZ reacts directly with reactive oxygen species to form taurine, while DTG is metabolized in δ‐tocopherol to achieve antioxidative activities. Methods After topical application to a hair follicle‐derived reconstructed human epidermis (RHE) model, followed by solar‐simulated radiation, kinetics of bioavailability and antioxidative responses were measured over 24 h. Markers for oxidative stress were malondialdehyde (MDA), superoxide dismutase (SOD) and catalase activities. Results The two antioxidants had different bioavailability profiles: OTZ was rapidly and extensively absorbed, whereas DTG was slowly absorbed and converted to δ‐tocopherol. Compared to OTZ alone, the protection against effects on MDA levels and SOD and catalase activities was higher when DTG was used alone or in combination with OTZ. When used in combination, the degree of protection increased over time and remained constant over 24 h with maximal protection 2 h post‐irradiation. DTG slowly penetrated into the skin and was present in the skin at all post‐irradiation timepoints, thus allowing a slow but constant supply of δ‐tocopherol over at least 24 h. By contrast, the oxidative protection by OTZ was immediate but short‐lived due to its rapid penetration through the RHE and into the receptor fluid. Conclusion These results indicate a complementary sunlight protective action of OTZ and DTG with an immediate delivery of OTZ just after topical application of the formulation, and a prolonged skin delivery of δ‐tocopherol from the slower penetration and metabolism of DTG.

No abstract

Several studies have shown that the ultraviolet (UVB/A) from terrestrial solar radiation are strongly implicated in the etiology of most skin cancers via the generation of DNA lesions and reactive oxygen species (ROS). Moreover, skin is also exposed to solar near infra-red (NIR) radiation which are responsible of oxidative stress generation. Therefore, it is important to protect the most sensitized skins (actinic keratosis or atopic dermatitis) in all circumstances/all day long. Thus, the aim of this project was to develop a SPF50+ sunfilter product in stick form to provide a nomad protection for sensitized skins. We demonstrated a very good genoprotection after an acute solar simulated irradiation in an in vitro reconstructed human epidermal (RHE) model with a very high protection of UV-induced cyclobutane pyrimidine dimers formation. Moreover, the quantification of ROS revealed that the topical application of sunscreen decreased significantly the free radical production in an ex vivo human skin model after acute UVA irradiation. In addition, the stick SPF50+ protection was evaluated on healthy subjects by the quantification of NIR-generated malondialdehyde (MDA), marker of lipid peroxidation. The topical application of the product decreased significantly the MDA production after NIR irradiation. Thus, the nomad sunfilter product provides an efficient protection against IR-generated oxidative stress. Finally, we showed that topical application of the sunscreen induced a physical barrier reinforcement on the RHE model by transepithelial electric resistance. Altogether, we demonstrated that the SPF50+ sunfilter stick shows a broad spectrum photoprotection not only UVB+A but also NIR, associated to a physical barrier reinforcement, providing a complete protection of the most sensitized skins.