The Impact of Flavonoid-Loaded Nanoparticles in the UV Protection and Safety Profile of Topical Sunscreens.

Excessive UV radiation exposure is harmful to skin cells since sunburn is accompanied by oxidative burst, leading to a rapid increase in skin cancer. However, the insufficient UV photoprotection of approved sunscreens and the negative impact of their compositions on ecosystems and human health makes the utility of sunscreen a questionable recommendation. Therefore, discovering UV filters with significant antioxidant activity and improved topical performance and photostability is an urgent need. Recently, the use of nanosized natural molecules incorporated in sunscreens has been a scientific hot topic, as it has been suggested that they provide a synergistic effect with synthetic UV filters, improving overall SPF and antioxidant activity, higher retention on the epidermis, and less toxicity. The aim of this review was to verify the usefulness of sunscreens incorporating flavonoid-loaded nanoparticles. A literature review was performed, where original and review articles published in the last 6 years were analyzed. Formulations containing nanosized flavonoids with improved UVA photoprotection and safer toxicological profiles, associated or not with synthetic filters, are promising sunscreens and more clinical investigation must be performed to validate these findings.

Evaluation of the Antitumour and Antiproliferative Effect of Xanthohumol-Loaded PLGA Nanoparticles on Melanoma.

Cutaneous melanoma is the deadliest type of skin cancer and current treatment is still inadequate, with low patient survival rates. The polyphenol xanthohumol has been shown to inhibit tumourigenesis and metastasization, however its physicochemical properties restrict its application. In this work, we developed PLGA nanoparticles encapsulating xanthohumol and tested its antiproliferative, antitumour, and migration effect on B16F10, malignant cutaneous melanoma, and RAW 264.7, macrophagic, mouse cell lines. PLGA nanoparticles had a size of 312 ± 41 nm and a PdI of 0.259, while achieving a xanthohumol loading of about 90%. The viability study showed similar cytoxicity between the xanthohumol and xanthohumol-loaded PLGA nanoparticles at 48 h with the IC50 established at 10 µM. Similar antimigration effects were observed for free and the encapsulated xanthohumol. It was also observed that the M1 antitumor phenotype was stimulated on macrophages. The ultimate anti-melanoma effect emerges from an association between the viability, migration and macrophagic phenotype modulation. These results display the remarkable antitumour effect of the xanthohumol-loaded PLGA nanoparticles and are the first advance towards the application of a nanoformulation to deliver xanthohumol to reduce adverse effects by currently employed chemotherapeutics.

Lower melanoma pulmonary metastatic burden in obese mice: role of FGF-21.

Obesity is a risk factor for malignant melanoma. The lungs are main target organs for metastization and their immune response is a key modulator of this mechanism. The concept that the metastatic potential of some types of cancer is reduced or inhibited by obesity, known as the obesity paradox, drives major concerns on the prognosis of metastasized patients. The aim of this study was to investigate how high-fat diet (HFD)-induced obesity affects melanoma metastization. C57Bl6/J mice were fed with HFD or standard diet for 180 days and inoculated intravenously with B16F10 melanoma cells. Upon 21 days of inoculation, lung tissue of overweight and lean mice was assessed for histology and immunohistochemistry assays. Adipokine antibody arrays were performed in mice serum. In vitro RAW 264.7 macrophage cultures were established and incubated with FGF-21 and/or lipopolysaccharide (LPS). Conditioned media was added to B16F10 cells for viability quantification. HFD-fed mice presented a reduced number of metastases with lower proliferative rates. The high content of inflammatory foci observed in noninoculated obese mice was significantly decreased upon B16F10 inoculation, concurrent with a slight fibrosis reduction. Plasma levels of fibroblast growth factor-21 (FGF-21), an endocrine regulator, were elevated in noninoculated HFD mice and the expression of FGF receptor 1 (FGFR-1) was significantly upregulated after inoculation. FGF-21 reduced melanoma viability in LPS-stimulated macrophages. Altogether, these findings suggest that higher amounts of FGF-21 are able to counterbalance the proinflammatory effects associated with obesity, protecting the lungs from melanoma metastization.

Starch-Capped AgNPs' as Potential Cytotoxic Agents against Prostate Cancer Cells.

One of the major therapeutic approaches of prostate cancer (PC) is androgen deprivation therapy (ADT), but patients develop resistance within 2-3 years, making the development of new therapeutic approaches of great importance. Silver nanoparticles (AgNPs) synthesized through green approaches have been studied as anticancer agents because of their physical-chemical properties. This study explored the cytotoxic capacity of starch-capped AgNPs, synthesized through green methods, in LNCaP and in PC-3 cells, a hormonal-sensitive and hormone-resistant PC cell line, respectively. These AgNPs were synthesized in a microwave pressurized synthesizer and characterized by ultraviolet-visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). Their cytotoxicity was assessed regarding their ability to alter morphological aspect (optical microscopy), induce damage in cytoplasmic membrane (Trypan Blue Assay), mitochondria (WST-1 assay), cellular proliferation (BrdU assay), and cell cycle (Propidium iodide and flow-cytometry). AgNPs showed surface plasmon resonance (SPR) of approximately 408 nm and average size of 3 nm. The starch-capped AgNPs successfully induced damage in cytoplasmic membrane and mitochondria, at concentrations equal and above 20 ppm. These damages lead to cell cycle arrest in G0/G1 and G2/M, blockage of proliferation and death in LNCaP and PC-3 cells, respectively. This data shows these AgNPs' potential as anticancer agents for the different stages of PC.