Search Results (584)

Ultraviolet B (UVB) radiation is a key factor in the overproduction of melanin in the skin. Melanocytes produce melanin through melanogenesis to protect the skin from UVB radiation-induced damage. However, excessive melanogenesis can lead to hyperpigmentation and increase the risk of malignant melanoma. Tyrosinase is the rate-limiting enzyme in melanogenesis; it catalyzes the oxidation of tyrosine to 3,4-dihydroxy-L-phenylalanine and subsequently to dopaquinone. Thus, inhibiting tyrosinase is a promising strategy for preventing melanogenesis and skin hyperpigmentation. White mulberry (Morus alba L.) is rich in antioxidants, and mulberry fruit extracts have been used as cosmetic skin-lightening agents. However, data on the capacity of mulberry fruit extracts to inhibit tyrosinase under UVB radiation-induced melanogenic conditions remain scarce, especially in an in vivo model. In this study, we evaluated the effects of a mulberry crude extract (MCE) on UVB radiation-induced melanogenesis in B16F10 melanoma cells and zebrafish embryos. The MCE significantly reduced tyrosinase activity and melanogenesis in a dose-dependent manner without inducing cytotoxicity. These effects are likely attributable to the antioxidant constituents of the extract. Our findings highlight the potential of this MCE as an effective tyrosinase inhibitor for the prevention of UVB radiation-induced skin hyperpigmentation. Full article

Melanoma is a highly aggressive skin cancer with limited therapeutic response. Targeting intracellular signaling pathways and promoting tumor cell differentiation are promising therapeutic strategies. Pentoxifylline (PTX) and norcantharidin (NCTD) have demonstrated antitumor properties, but their combined mechanisms of action in melanoma remain poorly understood. The effects of PTX (30 and 60 mg/kg) and NCTD (0.75 and 3 mg/kg), administered alone or in combination, in a DBA/2J murine B16-F1 melanoma model via intraperitoneal and intratumoral (IT) routes were evaluated. Tumor growth was monitored, and molecular analyses included RNA sequencing and immunofluorescence quantification of PI3K, AKT1, mTOR, ERBB2, BRAF, and MITF protein levels, and molecular docking simulations were performed. In the final stage of the experiment, combination therapy significantly reduced tumor volume compared to monotherapies, with the relative tumor volume decreasing from 18.1 ± 1.2 (SD) in the IT Control group to 0.6 ± 0.1 (SD) in the IT combination-treated group (n = 6 per group; p < 0.001). RNA-seq revealed over 3000 differentially expressed genes in intratumoral treatments, with enrichment in pathways related to oxidative stress, immune response, and translation regulation (KEGG and Reactome analyses). Minimal transcript-level changes were observed for BRAF and PI3K/AKT/mTOR genes; however, immunofluorescence showed reduced total and phosphorylated levels of PI3K, AKT1, mTOR, BRAF, and ERBB2. MITF protein levels and pigmentation increased, especially in PTX-treated groups, indicating enhanced melanocytic differentiation. Docking analyses predicted direct binding of both drugs to PI3K, AKT1, mTOR, and BRAF, with affinities ranging from −5.7 to −7.4 kcal/mol. The combination of PTX and NCTD suppresses melanoma progression through dual mechanisms: inhibition of PI3K/AKT/mTOR signaling and promotion of tumor cell differentiation. Full article

Turmeric oleoresin (TO), a natural pigment derived from Curcuma longa rhizomes, is valued for its health benefits, which are primarily attributed to its rich curcuminoid content (curcumin, demethoxycurcumin, and bisdemethoxycurcumin). Despite these benefits, curcuminoids are known to be light-sensitive and possess photosensitizing properties. This study investigated the impact of common light sources, fluorescent light and white LED (both at 10 W/m²), on the chemical stability, antioxidant activity, cytotoxicity, and photosensitizing properties of TO. Exposure to both light sources significantly reduced TO’s color and fluorescence intensity, with white LED causing greater instability. HPLC analysis confirmed a decrease in individual curcuminoid levels, with curcumin degrading most rapidly under both conditions. The DPPH radical scavenging activity of irradiated TO decreased compared to fresh or dark-stored turmeric, whereas its ABTS radical scavenging activity increased upon light exposure. Photosensitizing potency, measured by formazan decolorization and lipid peroxide formation, declined as TO decomposed under light. Conversely, the cytotoxicity of TO against B16F10 melanoma cells was significantly enhanced under light exposure, though this effect was diminished significantly after 24 h of pre-irradiation. These findings underscore the instability of turmeric pigment under common lighting conditions, which should be a crucial consideration when processing, storing, and distributing turmeric-containing products. Full article

Background: Liposomes and, more recently, structured nanolipid particles have demonstrated effectiveness as carriers for delivering hydrophilic or lipophilic anticancer agents, enhancing their biocompatibility, bioavailability, and sustained release to target cells. Objective: Herein, four doxorubicin formulations—comprising either the acidic or neutral form—were encapsulated into liposomes (Lipo) or nanostructured lipid carriers (NLCs) and characterized in terms of size, entrapment efficiency, morphology, and effects on two cancer cell lines (melanoma B16-F10 and breast carcinoma Walker 256 cells). Methods and Results: While liposomal formulations containing acidic doxorubicin displayed IC₅₀ values ranging from 1.33 to 0.37 µM, NLC-based formulations, particularly NLC-Doxo@Ac, demonstrated enhanced cytotoxicity with IC₅₀ values as low as 0.58 µM. Neutral Doxorubicin demonstrated lower cytotoxicity in both the nanoformulations and cell lines. Differences were also observed in their internalization patterns, cell-cycle impact, and apoptotic/necrotic effects. Compared to liposomes, NLCs exhibited distinct internalization patterns and induced stronger cell-cycle arrest and necrosis, especially in melanoma cells. Notably, NLC-Doxo@Ac outperformed liposomal counterparts in melanoma cells, while liposomal formulations showed slightly higher efficacy in Walker cells. Early and late apoptosis were more pronounced in Walker cells, whereas necrosis was more prominent in melanoma B16-F10 cells, particularly with the nanolipid formulations. Conclusions: These results correlated positively with cell-cycle measurements, highlighting the potential of NLCs as an alternative to liposomes for the delivery of neutral or acidic doxorubicin, particularly in tumor types that respond poorly to conventional formulations. Full article

Peptide vaccines possess several advantages over mRNA vaccines but are generally less effective at inducing antitumor immunity. The bottlenecks limiting peptide vaccine efficacy could be elucidated by tracking and comparing vaccine-induced T-lymphocytes in successful and unsuccessful cases. Here we have applied our recent database of neoantigen-specific T cell receptors (TCRs) to profile tumor-specific T cells following vaccination with a neoantigen peptide vaccine and to correlate this with the response. Mice were vaccinated prophylactically with p30 peptide encoding B16 melanoma neoantigen (K739N mutation in Kif18b gene). The B16F0 melanoma in the vaccinated mice was additionally treated by a CTLA-4 checkpoint blockade. T cells from the tumors, tumor-draining lymph nodes (tdLNs) and vaccine depots were isolated, phenotyped, sorted by subsets and sequenced for TCR repertoires. The vaccine induced the accumulation of tumor-specific CD4+ Th cells in the tdLNs, while in the tumors these cells were present and their frequencies were not changed by the vaccine. These cells also accumulated at the vaccine depots, where they were phenotypically skewed by the vaccine components; however, these effects were minor due to approximately 50-fold lower cell quantities compared to the tdLNs. Only some of the p30-specific Th cells showed tumoricidal activity, as revealed by the reverse correlation of their frequencies in the tdLNs with the tumor size. The CTLA-4 blockade did not affect the tumor growth or the frequencies of tumor-specific cells but did stimulate Th cell motility. Thus, we have shown that tumor-specific Th clones accumulate and/or expand in the tdLNs, which correlates with tumor suppression but only for some of these clones. Tumor infiltration by these clones is not correlated with the growth rate. Full article

Background: Quercetin is a flavonoid found in various dietary sources. It is a prodrug converted by overexpressed tyrosinase in melanoma into an active o-quinone that suppresses tumour growth. However, injected quercetin is rapidly cleared from the tumour site. Method: Our study aimed to enhance quercetin’s efficacy through nanoencapsulation using biodegradable nanocapsules, which were tested in both mouse and human melanoma cell lines in 2D and 3D models. Results: Nanoencapsulation achieved sustained release and improved bioavailability. In mouse 2D cultures, quercetin nanocapsules (Q-nanos) reduced cell viability to 28%, compared with 46% for free quercetin (Q-only) (p < 0.05). In 3D cultures simulating in vivo conditions, Q-nanos reduced viability to 43%, showing significant anti-melanoma activity, while Q-only resulted in 72% viability (p > 0.05 vs. control). A similar trend was observed in human melanotic melanoma, where both Q-nanos and Q-only were effective compared with the controls, with Q-nanos demonstrating superior tumour inhibition (p < 0.05). Conclusions: These findings show the superior efficacy of nanoencapsulated quercetin over free quercetin. Nanoencapsulation prolonged quercetin’s bioavailability, enhanced tumour regression, and addressed limitations associated with the rapid clearance of free quercetin. Full article

Caffeic acid (CA) is a naturally occurring polyphenol antioxidant found in coffee, tea, fruits, and vegetables, known for its strong antioxidant, anti-inflammatory, and anti-aging properties. However, its cosmetic application is limited because of poor dermal absorption due to its high polarity. This study aimed to evaluate the antioxidant and skin-brightening effects of a novel lipophilic CA derivative, CAD (caffeic acid-3,4-dihydroxyphenylpropanolester). CAD was synthesized by conjugating CA with 3,4-DHPEA, a lipophilic antioxidant derived from olive oil. In both DPPH and ABTS assays, CAD exhibited more potent antioxidant activity than CA. In B16F10 melanoma cells, CAD significantly inhibited melanin production without cytotoxicity at concentrations lower than those required for CA. Cellular assays using DCF-DA staining demonstrated that CAD effectively reduced intracellular ROS levels. Mechanistic studies revealed that CAD inhibited tyrosinase activity and downregulated the expression of TYR, TRP-1, and TRP-2. Additionally, CAD suppressed MITF phosphorylation, along with reduced phosphorylation of ERK and JNK, elucidating its anti-melanogenic mechanism. Importantly, CAD showed dose-dependent skin-brightening effects in the 3D human skin model Melanoderm™, as evidenced by increased lightness and histological evaluation. In conclusion, CAD demonstrates strong potential as a safe and effective antioxidant and skin-brightening agent for cosmetic applications. Full article

The flower buds of Magnolia biondii Pamp. (MBP), one of the botanical sources of Xinyi (Flos Magnoliae), are widely used in traditional medicine; however, their potential role in melanoma treatment remains unexplored. In this study, the phytochemical composition, antioxidant activity, and anti-melanoma mechanisms of MBP extracts were systematically investigated. Phytochemical profiling using UHPLC-Q-Exactive Orbitrap MS identified 26 bioactive compounds. The ethanol extract exhibited high total flavonoid and polyphenol contents, correlating with enhanced antioxidant capacity as demonstrated by DPPH and ABTS assays. Network pharmacology analysis highlighted the JAK/STAT signaling pathway, identifying STAT3 and STAT1 as core targets. Western blot analysis confirmed MBP significantly inhibited the phosphorylation of JAK1 and STAT1 in melanoma cells. Connectivity Map (CMap) and network analyses further pinpointed naringenin as a primary active constituent. In vitro assays demonstrated that MBP and naringenin inhibited the proliferation and migration of A375 and B16F10 melanoma cells, while exhibiting relatively low cytotoxicity toward normal keratinocytes. Molecular docking and dynamics simulations revealed strong and stable binding interactions between naringenin and JAK1/STAT1 proteins. These findings collectively support MBP and naringenin as promising candidates for melanoma treatment, providing mechanistic evidence for their targeted activity and laying a foundation for future research and clinical applications. Full article

Background/Objectives: Nucleic acid-based anticancer vaccines are becoming a very active field in the fight against cancer. Here, our goal was to generate an oral DNA vaccine targeting the angiogenic peptide, proadrenomedullin N-terminal 20 peptide (PAMP). Methods: An expression plasmid (PcPAMP) was generated by fusing the tetanus toxin epitopes P2 and P30 to the mouse PAMP sequence to counteract self-tolerance, and the empty plasmid was used as a negative control (PcNeg). The plasmids were introduced into Salmonella typhimurium bacteria that were then transformed into bacterial ghosts. C57BL/6J mice were orally immunized with the ghosts five times at 2-week intervals. Then, B16-F10 melanoma cells were injected into the tail vein to generate lung metastases. Furthermore, naïve CD4⁺ T cells were exposed to PAMP, and their secretome was analyzed by proximity extension assays. Results: Significant levels of anti-PAMP immunoglobulins were detected in the blood of PcPAMP-vaccinated mice and their levels of spleen CD8⁺ T cells were significantly higher than in those treated with PcNeg, indicating that self-tolerance was effectively broken. Although the number and size of lung metastases was similar between both experimental groups, there was a significant reduction in intratumoral angiogenesis and in cancer cell proliferation index in the PcPAMP group. Furthermore, these animals showed an intense infiltration of lymphocytes, including regulatory T cells, and M2-like macrophages into the metastases, that was not evident in the PcNeg group. In addition, PAMP induced upregulation of IL1β, IL6, IL7, IL12, IL27, TNFα, and FGF21, and downregulation of IL16 in naïve CD4⁺ T cells. Conclusions: Although the vaccine was not effective in reducing tumor growth, new proliferative and immune functions have been described for PAMP. These new functions include induction of melanoma proliferation and modulation of lymphocyte and macrophage tumor infiltration dynamics. Full article

Ganoderma leucocontextum, a newly identified species from the Tibetan Plateau, has been mainly studied for its polysaccharides and triterpenoids, with no prior reports on fungal immunomodulatory proteins (FIPs). This study explores the biological activity of FIP-gle2, cloned from G. leucocontextum and expressed in Pichia pastoris. The effects and mechanisms of recombinant FIP-gle2 (rFIP-gle2) on cell activity and melanin synthesis in mouse melanoma B16-F10 cells were investigated in vitro. The results showed that the FIP-gle2 gene, with an open reading frame (ORF) of 333 bp, encodes a 111-amino acid polypeptide with a molecular weight of 12.60 kDa and an isoelectric point of 4.48. We achieved a yield of 184.18 mg/L of rFIP-gle2. In vitro functional experiments showed that rFIP-gle2 significantly inhibited the proliferation of B16-F10 melanoma cells and induced apoptosis in a dose-dependent manner, particularly at concentrations above 1 μg/mL. At 3 μg/mL, rFIP-gle2 effectively inhibited tyrosinase activity and reduced melanin content, downregulating microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), and tyrosinase-related proteins (TRP-1 and TRP-2). Furthermore, RNA-seq analysis indicated that differentially expressed genes in treated cells were enriched in the mitogen-activated protein kinase (MAPK) signaling pathway, with Western blotting confirming enhanced phosphorylation of JNK, ERK, and p38 proteins. Thus, P. pastoris is an effective host for rFIP-gle2 production, which shows potential for applications in pharmaceuticals, cosmeceuticals, and food fields. Full article

Excessive melanogenesis causes abnormal pigmentation and a higher risk of skin disorders (e.g., melanoma). Resveratrol (RSV), a natural polyphenol, exerts antioxidant and anti-aging effects. However, the effects of RSV and its derivatives on melanogenesis remain unclear. This study investigated their effects on melanogenesis and antioxidant activity in B16F10 cells. After measuring cell viability, B16F10 cells were incubated with 50 µM of RSV, dihydroresveratrol (DIRSV), and other RSV derivatives for 24 h. The relative melanin content and tyrosinase activity were quantified. The protein and mRNA levels of melanogenesis-related genes (MITF, CREB, TYR, and TRP) and the binding affinity of RSV derivatives to their target proteins were measured. The antioxidant activity was evaluated using ABTS and DPPH assays. RSV and DIRSV (50 µM) significantly reduced melanin content and tyrosinase activity, respectively. However, other derivatives had no significant effects. RSV, DIRSV, and other derivatives significantly suppressed MITF and CREB levels. Additionally, DIRSV significantly reduced p-CREB and TYR protein levels and showed a higher affinity for CREB than RSV, despite no significant changes in MITF, TYR, or TRP mRNA levels. In the antioxidant assays, RSV and DIRSV exhibited significant ABTS and DPPH radical scavenging activities. DIRSV, like RSV, inhibits melanogenesis and exhibits antioxidant effects in B16F10 cells. However, RSV derivatives demonstrate partial antioxidant activity and inhibit melanogenesis-related proteins but do not significantly affect melanogenesis. DIRSV’s practical applications as a skin-protective and -whitening agent warrant further exploration. Full article

Pentagalloylglucose (PGG) is a powerful antioxidant and a naturally derived polyphenolic compound present in tannins. In this study, we investigated the ability of PGG to selectively inhibit hyperpigmentation through the regulation of melanogenesis in melanocytes. PGG inhibited melanin production in α-melanocyte-stimulating hormone (α-MSH)-induced B16F10 melanoma cells. Furthermore, PGG suppressed the expression of melanin synthesis enzymes, such as tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2. The mRNA and protein expression of the microphthalmia-associated transcription factor, which is involved in the mechanism of melanogenesis, was also reduced by PGG, and this effect was induced via PKA/CREB and MAPK phosphorylation. These results suggest that PGG inhibits α-MSH-induced melanin production by regulating the PKA/CREB/MAPK signaling pathway, indicating that natural compounds can serve as inhibitors of melanogenesis. Full article

We report the synthesis and characterization of five novel metal complexes. Three of them are vanadium complexes with the general formula [VO(Lⁿ)₂], where Lⁿ are Schiff bases derived from the condensation of 2-carbaldehyde-8-hydroxyquinoline with either 4-(2-aminoethyl)morpholine (L¹), 3-morpholinopropylamine (L²) or 1-(2-aminoethyl)piperidine (L³). The two other metal complexes are [Ni(L¹)₂] and [Fe(L¹)₂]Cl. They were characterized by analytical, spectroscopic (Fourier transform infrared, UV-visible absorption), and mass spectrometric techniques as well as by single-crystal X-ray diffraction (for all [VO(Lⁿ)₂] complexes and [Ni(L¹)₂]). While, in the crystal structure, the V(IV)O complexes show distorted square–pyramidal geometry with the ligands bound as bidentate through quinolate NO donors, the Ni(II) complex shows octahedral geometry with two ligand molecules coordinated through NNO donors. Stability studies in aqueous media revealed that the vanadium complexes are not stable, undergoing oxidation to VO₂(L), which was corroborated by ⁵¹V NMR and MS. This behavior is also observed in organic media, though at a significantly slower rate. The Ni complex exhibited small spectral changes over time in aqueous media. Nonetheless, all compounds show enhanced stability in the presence of bovine serum albumin (BSA). Fluorescence studies carried out for the Ni(II) and Fe(III) complexes indicate reversible binding to albumin. The cytotoxicity of the L¹ metal complexes was assessed on melanoma (B16F10 and A375) and colon cancer (CT-26 and HCT-116) cell lines, with 5-fluorouracil (5-FU) as a reference drug. The V- and Ni complexes showed the lowest IC₅₀ values (<10 μM) in either A375 or HCT-116 cells after 48 h of incubation, while the Fe(III) complex presented minimal antiproliferative effects. The complexes were generally more cytotoxic to human than murine cancer cells. Synergistic in vitro studies with 5-FU revealed antagonism in most cases, except in A375 cells, where an additive effect was observed for the combination with the V-complex. Overall, these compounds show promising potential for cancer treatment, mostly for melanoma. Full article

Melanoma is one of the deathliest cancers worldwide and its incidence is reaching epidemic proportions. It is characterized by intrinsic chemo-resistance, low response rates to treatment and high metastatic potential. Because of this, new therapeutic options are permanently required. Tessaria absinthioides (Hook. & Arn.) DC. is a traditional medicinal plant, with antioxidant, selective cytotoxicity and anti-colorectal cancer evidence-based properties. This study aims to demonstrate the antitumoral and antimetastatic effects of T. absinthioides decoction (DETa), correlating in vitro and in vivo activities in a murine melanoma model. DETa was assayed on B16F0 murine non-metastatic cells to determine cytotoxicity and clonogenicity; while, in the B16F10 metastatic siblings, adhesion, wound healing migration and Boyden chamber invasion were studied. The ex vivo intestinal-sac model was used to quantify DETa bioavailability. Meanwhile, in C57BL6/wt mice, DETa was orally administered to evaluate its antitumoral and antimetastatic activities. DETa induced cytotoxicity in a dose- and time-dependent manner, affecting the long-term clonogenic survival, as well as the processes of adhesion and migration. Then, the intestinal absorption of DETa phenolics was proven, while the systemic anti-tumoral and anti-metastatic activities of DETa were confirmed. Results demonstrated that DETa has antimelanoma activity promoting this botanical compound as a relevant agent for cancer research and treatment. Full article

The rhizomes of Boesenbergia rotunda (fingerroot) and its bioactive compound, panduratin A, exhibit potent anti-inflammatory, antioxidant, and anti-proliferative properties. The aim of this study was to investigate the anti-melanogenic (including anti-tyrosinase) effects of B. rotunda extract and panduratin A in B16F10 melanoma cells induced by UVA radiation. The effects of the compounds on fibroblast proliferation and migration were also assessed by scratch wound healing assays in human primary fibroblasts. The results showed that B. rotunda extract and panduratin A significantly reduced tyrosinase activity and cellular melanogenesis induced by UVA radiation in a dose-dependent manner. The compounds also demonstrated inhibitory effects on fibroblast cell migration and proliferation. These findings suggest that B. rotunda extract may have potential therapeutic effects on skin hyperpigmentation and fibroproliferative skin disorders. Full article