Chronic UVB exposure promotes oxidative stress, directly causes molecular damage, and induces aging-related signal transduction, leading to skin photoaging. Dihydrocaffeic acid (DHCA) is a phenolic compound with potential antioxidant capacity and is thus a promising compound for the prevention of UVB-induced skin photodamage. The aim of this study was to evaluate the antioxidant and protective effect of DHCA against oxidative stress, apoptosis, and matrix metalloproteinase (MMP) expression via the mitogen-activated protein kinase (MAPK) signaling pathway on L929 fibroblasts irradiated with UVB. DHCA exhibited high antioxidant capacity on 2,2-diphenyl-1-picrylhydrazyl (DPPH^•), 2,2-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS^•+), and xanthine/luminol/xanthine oxidase (XOD) assays and reduced UVB-induced cell death in the neutral red assay. DHCA also modulated oxidative stress by decreasing intracellular reactive oxygen species (ROS) and extracellular hydrogen peroxide (H₂O₂) production, enhancing catalase (CAT) and superoxide dismutase (SOD) activities and reduced glutathione (GSH) levels. Hence, cellular damage was attenuated by DHCA, including lipid peroxidation, apoptosis/necrosis and its markers (loss of mitochondria membrane potential, DNA condensation, and cleaved caspase 9 expression), and MMP-1 expression. Furthermore, DHCA reduced the phosphorylation of MAPK p38. These findings suggest that DHCA can be used in the development of skin care products to prevent UVB-induced skin damage.

Exposure to ultraviolet radiation induces photodamage towards cellular macromolecules that can progress to photoaging and photocarcinogenesis. The topical administration of compounds that maintain the redox balance in cells presents an alternative approach to combat skin oxidative damage. Cerium oxide nanoparticles (CNPs) can act as antioxidants due to their enzyme-like activity. In addition, a recent study from our group has demonstrated the photoprotective potential of tannic acid (TA). Therefore, this work aimed to synthesize CNPs associated with TA (CNP-TA) and investigate its photoprotective activity in L929 fibroblasts exposed to UVB radiation. CNP conjugation with TA was confirmed by UV–Vis spectra and X-ray photoelectron spectroscopy. Bare CNPs and CNP-TA exhibited particle sizes of ~5 and ~10 nm, superoxide dismutase activity of 3724 and 2021 unit/mg, and a zeta potential of 23 and −19 mV, respectively. CNP-TA showed lower cytotoxicity than free TA and the capacity to reduce the oxidative stress caused by UVB; supported by the scavenging of reactive oxygen species, the prevention of endogenous antioxidant system depletion, and the reduction in oxidative damage in lipids and DNA. Additionally, CNP-TA improved cell proliferation and decreased TGF-β, metalloproteinase-1, and cyclooxygenase-2. Based on these results, CNP-TA shows therapeutic potential for protection against photodamage, decreasing molecular markers of photoaging and UVB-induced inflammation.

Oxidative stress is commonly defined as an imbalance between reactive oxygen species (ROS) production and an organism’s ability to neutralize them via antioxidant defense mechanisms, leading to damage to biomolecules, including lipids, proteins, and DNA

Cancer treatment continues to face significant challenges, including lack of selectivity, systemic toxicity, and the adaptive resistance mechanisms of cancer cells, which limit the effectiveness of conventional therapies. Nanomedicine offers a promising solution, using nanocarriers for targeted drug delivery, improved bioavailability, and reduced off-target effects due to properties such as the enhanced permeability and retention (EPR) effect and advanced surface modifications. Additionally, the integration of theranostic capabilities allows for real-time monitoring of treatment efficacy. However, the clinical translation of nanocarriers remains restricted due to the limitations of existing predictive models. Traditional two-dimensional (2D) in vitro models often fail to replicate the complexity of the human tumor microenvironment (TME), leading to discrepancies between preclinical and clinical outcomes. More sophisticated models have been developed to address these challenges, including three-dimensional (3D) tumor spheroids, organoids, and microfluidic tumor-on-a-chip (ToC) systems. These models offer a more accurate representation of the TME, enabling better assessment of nanoparticle penetration, retention, and therapeutic effects, while also reducing reliance on animal models. This review provides a comprehensive analysis of the in vitro models used to evaluate the anti-tumoral effects of nanocarriers alongside the methodologies employed to assess their safety and efficacy. Specifically, we explore the evolution from 2D monolayer cultures to advanced 3D systems, including tumor spheroids, organoids, and ToC platforms, and delve into the main methodologies employed to evaluate nanoparticle behavior, including cellular uptake mechanisms, cytotoxicity assays (e.g., MTT, WST-1/WST-8, LDH, Live/Dead assays), cell death mechanisms (e.g., apoptosis, necrosis, and autophagy), signaling pathways exploring gene expression analysis (qRT-PCR, RNA-seq, microarrays) and protein expression analysis (western blot, immunochemistry, mass spectrometry), oxidative stress evaluation, and cell migration/invasion assays (e.g., scratch/wound-healing, transwell, and microfluidic chip-based models). Furthermore, we cover clonogenic assays for assessing long-term cell survival, and cytoskeleton evaluation to understand how nanoparticles affect cell structure. By highlighting the advantages and limitations of these models and methodologies, this review aims to guide researchers in selecting the most appropriate experimental approaches, ultimately supporting the development of more effective nanomedicine-based cancer therapies.