Breast cancer is now the most common type of cancer worldwide, surpassing lung cancer. This issue is further worsened by the lack of effective therapies for the disease. Recent reports indicate that the inhibition of ubiquitin-like modifier-activating enzyme 5 (UBA5) can impede tumor development. However, there have been few reports regarding UBA5-inhibiting compounds. This work studied usenamine A, a natural product from the lichen Usnea longissimi that exhibits UBA5-inhibitory effects. Bioinformatics analysis was performed using public databases, and the anti-proliferative ability of usenamine A in breast cancer cells was examined through MTS and colony formation assays. Flow cytometry and western blot analysis were also conducted to examine and analyze cell cycle arrest and apoptosis. In addition, LC3B-RFP and UBA5 expression plasmids were used for the analysis of usenamine A-induced autophagy. According to the bioinformatics analysis results, UBA5 was upregulated in breast cancer. According to in vitro studies, usenamine A displayed prominent anti-proliferative activity and resulted in G2/M phase arrest in MDA-MB-231 cells. Moreover, usenamine A induced autophagy and endoplasmic reticulum stress in MDA-MB-231 cells. In conclusion, the findings support the potential of usenamine A as an agent that can attenuate the development and progression of breast cancer.

Drug-resistant infectious diseases pose a substantial challenge and threat to medical regimens. While adaptive laboratory evolution provides foresight for encountering such situations, it has inherent limitations. Novel drug delivery systems (DDSs) have garnered attention for overcoming these hurdles. Multi-stimuli responsive DDSs are particularly effective due to their reduced background leakage and targeted drug delivery to specific host sites for pathogen elimination. Bacterial infections create an acidic state in the microenvironment (pH: 5.0–5.5), which differs from normal physiological conditions (pH: 7.4). Infected areas are characterized by the overexpression of hyaluronidase, gelatinase, phospholipase, and other virulence factors. Consequently, several effective stimuli-responsive DDSs have been developed to target bacterial pathogens. Additionally, biofilms, structured communities of bacteria encased in a self-produced polymeric matrix, pose a significant challenge by conferring resistance to conventional antimicrobial treatments. Recent advancements in nano-drug delivery systems (nDDSs) show promise in enhancing antimicrobial efficacy by improving drug absorption and targeting within the biofilm matrix. nDDSs can deliver antimicrobials directly to the biofilm, facilitating more effective eradication of these resilient bacterial communities. Herein, this review examines challenges in DDS development, focusing on enhancing antibacterial activity and eradicating biofilms without adverse effects. Furthermore, advances in immune system modulation and photothermal therapy are discussed as future directions for the treatment of bacterial diseases.

Prolonged exposure to fine dust (FD) increases the risk of skin inflammation. Stimulated epidermal cells release growth factors into their extracellular environment, which can induce inflammation in dermal cells. Algae are considered rich sources of bioactive materials. The present study emphasized the effect of low-molecular-weight fucoidan isolated from Sargassum confusum (LMF) against FD-induced inflammation in HaCaT keratinocytes and underneath fibroblasts (HDFs) in an integrated culture model. HDFs were treated with media from FD-stimulated HaCaT with LMF treatments (preconditioned media). The results suggested that FD increased the oxidative stress in HaCaT, thereby increasing the sub-G₁ phase of the cell cycle up to 587%, as revealed via flow cytometric analysis. With preconditioned media, HDFs also displayed oxidative stress; however, the increase in the sub-G₁ phase was insignificant compared with HaCaT. LMF dose-dependently regulated the NF-κB/MAPK signaling in HaCaT. Furthermore, significant downregulation in NF-κB/MAPK signaling, as well as inflammatory cytokines, tissue inhibitors of metalloproteinases, matrix metalloproteinases, and reduction in relative elastase and collagenase activities related to the extracellular matrix degeneration were observed in HDFs with a preconditioned media treatment. Therefore, we concluded that HDFs were protected from inflammation by preconditioned media. Continued research on tissue culture and in vivo studies may reveal the therapeutic potential of LMF.