A general tyrosinase-responsive prodrug strategy: design and synthesis of melanoma-selective anticancer agents.

Oxidative stress contributes to skin damage and hyperpigmentation through excessive melanin production. Tyrosinase plays a central role in melanogenesis by catalyzing the oxidation of tyrosine to melanin precursors. Although several tyrosinase inhibitors are available, their clinical use is limited due to adverse effects. Therefore, identifying safer inhibitors with concomitant antioxidant properties remains of considerable interest. In ethnomedicine, Urtica urens L. (Urticaceae) is traditionally used to treat inflammatory conditions. This study aims to evaluate the antioxidant, tyrosinase inhibitory, and photoprotective activities of its ethanolic extract. Here, 80% ethanolic extract of U. urens aerial parts (E) was chemically characterized and standardized based on total polyphenol, flavonoid, and chlorogenic acid contents. Antioxidant activity was assessed by inhibiting UV-induced lipid peroxidation in egg yolk. Tyrosinase inhibitory activity was evaluated using mushroom tyrosinase, and kinetic analysis was conducted to determine the inhibition mechanism. The in vitro sun protection factor was also determined. E inhibited UV-induced lipid peroxidation (EC50 = 44.4 µg/mL) and exhibited tyrosinase inhibitory activity (EC50 = 1,016 µg/mL, relative to the maximal observed effect), with a mixed-type inhibition pattern. The extract also showed in vitro photoprotective capacity. Chlorogenic acid was identified as the major polyphenolic constituent; although it exhibited antioxidant and anti-tyrosinase activities, its concentration in the extract did not fully account for the overall inhibitory effect observed. The findings indicate that the biological activities of E likely result from the combined action of multiple phytochemical constituents. These findings support its potential as a source of bioactive compounds for cosmetic and dermatological applications targeting oxidative and pigmentation-related skin alterations.

Advancements in 3D bioprinting demand bioinks that demonstrate not only precise printability and mechanical robustness but also consistent biochemical and cellular performance. From previous iterations in our laboratory, a silk fibroin-gelatin (SF-G) bioink was conjugated with mushroom tyrosinase (MT) as the enzymatic crosslinker. However, its clinical translation was hindered by several limitations, including batch-to-batch variation in concentration and enzymatic activity, protracted gelation kinetics, and inconsistent rheological and structural characteristics. To overcome these challenges, we developed a next-generation SF-G bioink employing horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) as an alternative enzymatic crosslinking system. This approach facilitated rapid and tunable crosslinking through β-sheet enhancement, yielding hydrogels with improved stiffness, shape fidelity, and resistance to enzymatic degradation. Detailed rheological analysis confirmed optimal shear-thinning behaviour and print fidelity, while reactive oxygen species (ROS) quantification ensured cytocompatibility across physiologically relevant concentrations. Human bone marrow-derived mesenchymal stem cells (hBMSCs) encapsulated within the constructs maintained high viability and demonstrated robust osteogenic and chondrogenic lineage commitment. Furthermore, supplementation with triiodothyronine (T3) and transforming growth factor-β3 (TGF-β3) augmented matrix deposition and tissue-specific morphogenesis. Notably, a 10 U HRP-H2O2 formulation emerged as the most promising candidate, offering a strategic balance of mechanical integrity, bioactivity, and reproducibility. This optimized enzymatic system paves the way for scalable and clinically viable SF-G bioinks tailored for advanced tissue engineering and regenerative medicine applications.

This study introduces a unified framework combining artificial intelligence (AI)-directed de novo molecular generation with dual-track lead optimization-comprising expert-guided strategies and AI-driven pathways-to discover tyrosinase (TYR) inhibitors for hyperpigmentation disorders. Using a reinforcement learning (RL)-based generative model, the lead compound AI10 was identified. Subsequent optimization followed two parallel routes. The expert-guided approach yielded AI10-m15 as the most potent TYR inhibitor, with notable antipigmentation activity and excellent cellular safety profiles. In contrast, the AI-driven pathway explored broader chemical spaces, generating unconventional chemotypes, exemplified by the potent TYR inhibitor AI10-a2, highlighting AI's capacity to uncover nonintuitive activity cliffs despite greater output variability. Systematic comparison revealed that the AI model offers exploratory diversity, whereas expert-guided optimization provides predictable improvements in activity and developability. In summary, starting from an AI-generated lead and subsequently integrating both expert-guided and AI-driven structural optimization strategies, these findings further underscore that combining AI technologies with experts' medicinal chemistry insights can substantially accelerate the discovery of viable candidate compounds.

Significant loss of pigmentation can increase visual disability, skin cancer risk, and psychosocial stress. Tyrosinase (TYR) catalyzes the first and rate-limiting step of melanin synthesis. Inhibitors of TYR are well established and are currently used in clinical settings; however, there is a dearth of direct activators of TYR. Here, using a human TYR construct, we developed high-throughput screening methods, in cell confirmatory assays employing 13C-tyrosine tracing, and computational analysis techniques, and identified ampyrone (4-aminoantipyrine) as a TYR activator. Ampyrone increased the in vitro catalytic activity of the human recombinant intra-melanosomal domain of TYR (hTYR) and its hypomorphic variant, Pro406Leu (P406L), a cause of oculocutaneous albinism type 1B (OCA1B). Moreover, ampyrone induced melanin synthesis in both wild-type and OCA1B human melanocytes, mouse OCA2 melanocytes, as well as 3-dimensional (3D) human skin cultures. Computational studies provided additional insight into the effects of direct TYR agonists on enzyme activity. Our results identified ampyrone as a lead candidate for TYR activation, potentially supporting the development of therapies for patients with genetic and acquired diseases of hypopigmentation.

Cannabidiol-thiosemicarbazone exhibits dual tyrosinase inhibition and antioxidant activity in human skin-derived cells.

The distinct characteristics of the tumor microenvironment (TME) provide great potential for valuable tumor-targeting therapies using enzymes. Herein, MOF-818 with a diameter of 139nm is synthesized and exhibits multienzyme-mimicking activities, including peroxidase, catalase, glutathione oxidase, glucose oxidase, superoxide dismutase, and tyrosinase (TYR)-like activities. Based on these enzymatic activities, MOF-818 catalyzes an entire process that progresses through self-generated substrates and cyclic catalytic reactions, and notably induces TME remodeling. Synchronously, for the first time reported in nanozymes, MOF-818 activates the prodrug acetaminophen (APAP) through its TYR-like activity, further increasing reactive oxygen species accumulation. These features contribute to MOF-818's antitumor activity by activating multiple combined programmed cell death pathways: apoptosis, disulfidptosis, and cuproptosis. The MOF-818 nanoplatform, 3-methyladenine (3-MA), THP-1 cell membranes, and a fusion protein of Fc and TNF-related apoptosis-inducing ligand (Fc-TRAIL) were integrated to construct 3-MA@MOF-818@CM-Fc-TRAIL nanoparticles (3MCT NPs). These NPs target tumor cells and, when coupled with APAP, show efficient therapeutic effects with good biosafety. Our findings indicate that the MOF-818 could function as a multienzyme-mimetic scaffold for engineering targeted nanoplatforms that co-deliver combinatorial therapeutic agents, thereby enabling combined antitumor therapy.

ABSTRACTBackgroundSkin hyperpigmentation disorders affect millions worldwide, driving demand for depigmentation products. However, many conventional skin‐lightening products contain dangerous ingredients, including mercury and unregulated hydroquinone.AimsPlant‐derived exosome‐like vesicles represent promising natural therapeutic agents due to their biocompatibility and ability to deliver bioactive compounds. This study aimed to isolate and characterize cucumber‐derived exosome‐like vesicles (cEVs) and evaluate their melanin‐inhibitory effects and biosafety profile.MethodsCucumber‐derived exosomes were isolated using differential centrifugation, filtration, and ultrafiltration. Physicochemical characterization was performed using nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and SDS‐PAGE. The vesicular identity of purified cEVs was further validated by immunoblotting for established plant EV marker proteins PEN1 and TET8. Cytotoxicity and melanin‐inhibitory effects were assessed in MNT‐1 human melanoma cells. Melanogenic gene and protein expression of tyrosinase (TYR) and tyrosinase‐related protein 1 (TRP‐1) were assessed by qRT‐PCR and immunoblotting, respectively.ResultsPurified cEVs exhibited physicochemical and morphological characteristics consistent with plant‐derived extracellular vesicles, including a mean diameter of 106.7 ± 1.4 nm, spherical morphology, intact membrane structures, and detectable expression of plant EV marker proteins PEN1 and TET8. The cEVs demonstrated no detectable cytotoxicity within the tested concentration range across concentrations of 3.9 × 108 to 2.5 × 1010 particles/mL (> 95% MNT‐1 cell viability; 99.9% reconstructed human epidermis viability; classified as non‐irritating per UN GHS criteria). At the highest concentration, cEVs reduced melanin to approximately 75% of control, comparable to kojic acid and α‐arbutin, with immunoblotting confirming dose‐dependent downregulation of TYR protein expression consistent with the observed melanin‐inhibitory activity.ConclusionsCucumber‐derived exosome‐like vesicles demonstrate concentration‐dependent melanin‐inhibitory activity without detectable cytotoxicity or skin irritation within the tested conditions, warranting further investigation as candidate naturally‐derived alternatives to conventional skin‐lightening products, warranting further preclinical investigation.

Tyrosinase (TYR) is a copper-containing metalloenzyme involved in melanin biosynthesis and is an important target in the development of treatments for hyperpigmentation disorders, including melasma, post-inflammatory hyperpigmentation, and melanoma. Among the scaffold classes investigated for TYR inhibition, 1,2,4-triazole derivatives have attracted increasing interest. In this study, we evaluated a structurally diverse series of triazole derivatives using an integrated computational workflow that included absorption, distribution, metabolism, excretion and toxicity (ADMET) profiling, molecular docking, molecular dynamics (MD) simulations, and binding free energy calculations based on Linear Interaction Energy (LIE) and Free Energy Perturbation (FEP). Using Bacillus megaterium TYR as the model enzyme, the triazole derivatives generally produced more favorable docking scores than kojic acid and established recurring interactions with hydrophobic residues such as Met215, Val217, Ala221, and Phe227, as well as hydrogen-bonding contacts with Gly216. The free energy calculations reproduced the experimental binding affinities with high accuracy (FEP: R² = 0.91, MAE = 0.20kcal/mol; LIE: R² = 0.93, MAE = 0.54kcal/mol). Residue-level energy analysis indicated that interactions involving Arg209, Gly216 and Val218 play a major role in ligand binding across the series, with aromatic and halogenated substituents favoring stronger van der Waals contacts in this region. Overall, these results provide a consistent structural and energetic framework for understanding triazole-based TYR inhibition and may support the rational design of improved inhibitors for cosmetic and therapeutic applications.

Background: Baeckea frutescens L. (BF) has been reported as a potential natural source for skin-whitening agents. However, its antimelanogenic activity and mechanisms remain unclear. Methods: The antimelanogenic effects of BF were evaluated in α-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 cells and in zebrafish embryos. Cell viability, intracellular tyrosinase activity and melanin content were measured. Western blot (WB) analysis was used to examine melanogenesis-related proteins. Network pharmacology and molecular docking were performed to predict potential targets and interactions of BF-derived metabolites. Results: The ethanolic extract of BF reduced intracellular tyrosinase activity and melanin content in cells without cytotoxicity. Western blot analysis showed decreased expression of microphthalmia-associated transcription factor (MITF) and its downstream melanogenic enzymes, including tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1), and dopachrome tautomerase (DCT). In addition, BF reduced phosphorylation of protein kinase A (PKA), cAMP responsive element-binding protein (CREB) and extracellular signal-regulated kinase (ERK), suggesting potential suppression of PKA/CREB and ERK signaling pathways. These regulatory effects may contribute to MITF downregulation and subsequent inhibition of melanogenesis. BF reduced melanin accumulation in zebrafish embryos. Network pharmacology and molecular docking analyses further suggested that BF-derived metabolites, particularly bayogenin, may interact with multiple melanogenesis-related targets. Conclusions: BF may inhibit melanogenesis through coordinated modulation of multiple signaling pathways and may represent a promising skin-whitening candidate.

Sulfur quantum dots (SQDs), as an emerging member of the fluorescent quantum dot family, hold great promise for application in biological analysis and environmental health. However, their intrinsic resistance to fouling in complex matrix pollution is rarely reported. Herein, we report the remarkable antifouling properties of polyethylene glycol (PEG)-modified SQDs, which exhibit 100% fluorescence retention under harsh conditions, including high salinity (2 M), high temperature (90 °C), and high protein concentration (150 mg/mL). Through fluorescence quenching experiments and density functional theory (DFT) calculations, we elucidate the mechanistic origin of the differential antifouling behavior between PEG-SQDs and carboxymethyl cellulose (CMC)-modified SQDs (CMC-SQDs). DFT calculations reveal that CMC strongly polarizes H2O (dO-H = 1.026 Å), making it more prone to protein adsorption. In contrast, PEG induces substantially weaker polarization of H2O (dO-H = 0.980 Å), effectively inhibiting the adsorption of various hydrophilic biomacromolecules. Leveraging the excellent antifouling performance of PEG-SQDs, we developed a strategy for detecting tyrosinase (TYR) activity. This strategy is based on TYR-catalyzed oxidation of l-tyrosine to melanin-like products, which efficiently quench the fluorescence of PEG-SQDs. Ultimately, a highly sensitive, selective, simple, and environmentally friendly method for TYR detection has been constructed. This method exhibits a linear response range for TYR from 0.5 to 20 U/mL, with a detection limit of 0.08 U/mL (S/N = 3). Furthermore, it enables accurate quantification of TYR activity in human serum samples, underscoring the excellent antifouling capability of PEG-SQDs in complex biological matrices. Overall, this work not only provides a novel tool for the sensitive detection of TYR but also offers new insights into the antifouling mechanism of SQDs.

Excessive melanin accumulation causes hyperpigmentation, a skin pathophysiology that highlights the need for safe and multifunctional skin-whitening agents. Building on the reported tyrosinase inhibitory potential of phenylthiazole derivatives, a series of compounds was designed and synthesized to investigate the structural determinants of their multi-functional activities. The biological evaluation included mushroom tyrosinase (mTYR) inhibition, as well as anti-melanogenic, anti-inflammatory, and antioxidant assays. Among the series, compound 3c exhibited the most potent multi-functional profile, showing mTYR inhibition (IC50 = 30.8 ± 2.7 µM) with a mixed-type inhibitory mechanism (Ki = 20 µM), a 34% reduction in melanin content at 40 µM, significant nitric oxide inhibition (IC50 = 33.7 ± 2.0 µM), and strong antioxidant activity (SC50 = 29.0 ± 0.8 µM). Density Functional Theory (DFT) calculations and predicted physicochemical properties indicate that 3c possesses favorable molecular stability and promising potential for skin penetration. Molecular docking and molecular dynamics (MD) simulations further demonstrated that 3c stably occupies the active pocket of human tyrosinase-related protein 1 (TYRP1, PDB ID: 5M8M), forming key interactions with Zn2+-coordinating residues and maintaining a stable energetic profile. Collectively, these findings indicate that 3c exhibits the most balanced multi-functional activity within the series and holds promise as a lead compound for topical skin-whitening applications.

Determination of dissociation constants between single-protein and multicomponents by a multi-chamber membrane separation electrophoresis system as a complementary tool.

The aim of this study was to investigate the anti-melanogenic effects and underlying mechanisms of PFRMY (Pro-Phe-Arg-Met-Tyr), a pentapeptide derived from tilapia skin (Oreochromis niloticus), using B16F10 murine melanoma cells. Treatment with PFRMY (1.0 mg/mL) significantly reduced intracellular melanin content and tyrosinase (TYR) activity by 39.55 ± 1.51% and 32.46 ± 1.31%, respectively. RT-PCR and Western blotting analyses revealed that PFRMY suppressed melanogenesis through the α-MSH/PKA/CREB signaling pathway. Notably, PFRMY reversed α-MSH-induced upregulation of key downstream factors including PKA, CREB, MITF, and TYR, while showing minimal effects on the protein expression of MC1R or α-MSH. Molecular docking further suggested that PFRMY binds to MC1R with higher affinity than α-MSH, potentially occupying the ligand-binding site and thereby interfering with downstream signaling. Collectively, these findings demonstrate that PFRMY effectively inhibits melanogenesis by competitively antagonizing the α-MSH/MC1R axis, highlighting its potential as a safe and efficacious ingredient for hyperpigmentation treatment and cosmetic applications.

Hyperpigmentation disorders stem from tyrosinase-catalyzed melanin overproduction, worsened by ultraviolet oxidative stress. The native Chilean species Cryptocarya alba, Laurelia sempervirens, and Peumus boldus are sources of aporphine and benzylisoquinoline alkaloids, known for their antioxidant activity. Boldine derivatives, notably diacetylboldine (DAB, Lumiskin™), demonstrate commercial depigmenting efficacy, yet structure-activity relationship data are limited.​. Systematically evaluate pure alkaloids and boldine derivatives for tyrosinase inhibition via mushroom enzyme assays, molecular docking, human melanocyte (HEMn-DP), and 3D epidermal (MelanoDerm™) models to elucidate depigmenting mechanisms. Boldine (BOL), N-methyllaurotetanine (NMLT), laurolitsine (LTS), laurotetanine (LTT), and reticuline (RET) alkaloids were isolated from authenticated plant material via acid-base partitioning/silica gel chromatography; structures were confirmed by 1H-NMR/UHPLC-MS/MS (98% HPLC purity). Coclaurine (CC), N-methylcoclaurine (NMCC), and BOL derivatives: 3-bromoboldine (3BrBOL) and DAB were synthesized. Isocorydine (ISO) was obtained commercially. Mushroom tyrosinase (EC 1.14.18.1) inhibition measured spectrophotometrically (475nm, L-DOPA; IC50 interpolation). Docking performed on A. bisporus tyrosinase (PDB:2Y9X) with AutoDock Vina (30 × 30 × 30Å grid). HEMn-DP cells treated (40/250ppm, 24h) for MTS viability and alkali-solubilized melanin (450nm). MelanoDerm™ tissues were dosed topically (0.1% w/v) for 14 days, followed by the Solvable™ melanin assay (490nm). Data analyzed in GraphPad Prism 8 (Dunnett's test, P < 0.05). LTS (IC50 = 0.96mM), an aporphine alkaloid, followed by CC (1.29mM), a benzylisoquinoline alkaloid, were the most potent mushroom tyrosinase inhibitors, outperforming BOL 6.8- and 5.1-fold (6.56mM), respectively, yet trailing reference standards such as kojic acid (0.014mM). Boldine derivatives, including DAB (2.22mM) and 3BrBOL (1.96mM), exhibited superior potency relative to the parent compound. Docking revealed LTS's highest affinity (-7.3kcal/mol; H-bonds: His259 3.4Å, Asn260 3.2Å) versus BOL (-5.3kcal/mol; solely van der Waals), explained by NH-mediated His263 interaction absent in N-methylated boldine. In addition, hemisynthetic alkaloids (3BrBOL and DAB) show interactions and affinity energies similar to those of BOL. In HEMn-DP (40ppm, 24h), BOL/3BrBOL achieved 100% tyrosinase inhibition (viability ∼50%), exceeding DAB (62%). MelanoDerm™ (0.1% w/v, 14 days): results confirmed the efficacy of 3BrBOL (-33% melanin, P < 0.05; ∼arbutin), BOL (-10%), and DAB/LTS inactivity, highlighting the superiority of C-3 halogenation. LTS is the premier natural inhibitor; optimization of 3BrBOL validates BOL derivatization for ARB equivalent depigmentation in 3D models. These findings support the development of hydroquinone-free cosmeceuticals from Chilean flora alkaloids and advocate the use of nanoemulsions to enhance delivery and reduce cytotoxicity.

The present study designed to assess the antityrosinase and antioxidant activities of succeeding solvent extracts of Pleurotus ostreatus (oyster mushroom). Dried mushroom powder was successively extracted using hexane (HEPO), dichloromethane (DMEPO), ethyl acetate (EAEPO), and ethanol (EEPO). Physicochemical parameters and preliminary phytochemical screening were completed using standard pharmacognostic methods. Antioxidant activity was assessed by DPPH, hydrogen peroxide (H₂O₂), and ABTS radical scavenging assays, while tyrosinase inhibitory activity was assessed spectrophotometrically using L-tyrosine as substrate. Hydroquinone monomethyl ether (HQMME) and arbutin were used as reference standards. Amongst all extracts, EAEPO and EEPO exhibited superior antioxidant activity. In the DPPH assay, IC₅₀ values for HEPO, DMEPO, EAEPO, and EEPO were 96.86, 113.65, 63.62, and 58.69 μg/mL, respectively, compared to 81.58 μg/mL for ascorbic acid. In the H₂O₂ scavenging assay, EEPO showed strong activity with an IC₅₀ of 113.11 μg/mL, comparable to ascorbic acid (112.38 μg/mL). ABTS radical scavenging results further confirmed the superior antioxidant potential of EEPO (IC₅₀ 75.87 μg/mL) and EAEPO (IC₅₀ 123.73 μg/mL). Tyrosinase inhibition studies discovered that EAEPO and EEPO significantly inhibited mushroom tyrosinase activity in a concentration-dependent manner, comparable to standard inhibitors. nThe enhanced biological activities of EAEPO and EEPO correlate with their high phenolic, flavonoid, and tannin contents, as confirmed by quantitative estimations. The findings suggest that ethyl acetate and ethanol extracts of Pleurotus ostreatus are promising natural sources of antioxidant and tyrosinase inhibitory compounds, supporting their potential application in cosmeceutical and pharmaceutical formulations for skin depigmentation and oxidative stress management

A dual-locked fluorescent probe for imaging of human primary melanocytes and melanoma tissues via tyrosinase and hydrogen sulfide activation.

Discovery and mechanistic elucidation of 2,4-resorcinol-based potent human tyrosinase inhibitors through integrated experimental and computational approaches.

Hyperpigmentation, caused by excessive melanin accumulation, is a significant cosmetic concern in dermatology. Natural compounds are receiving attention as safe and effective skin-lightening agents due to their antioxidant properties and ability to inhibit melanin synthesis. To investigate the antioxidant and melanin biosynthesis inhibitory effects of leatherleaf fern water extract (LFWE) and the skin-lightening efficacy of a facial serum containing LFWE through invitro and clinical trials: MATERIALS AND METHODS: The antioxidant and tyrosinase inhibitory activities of LFWE were confirmed invitro, along with its inhibitory effects on factors involved in melanin biosynthesis. Its skin-lightening effects were then validated through clinical trials. LFWE demonstrated excellent 1,1-diphenyl-2-picrylhydrazyl and ABTS cation radical scavenging activity and inhibited mushroom tyrosinase activity in a concentration-dependent manner. LFWE also suppressed melanin biosynthesis in B16-F10 melanoma cells without toxicity up to 500 μg/mL and significantly inhibited the protein expression levels of tyrosinase, TRP-1, and TRP-2, which promote melanin production. Clinical trials of a serum containing LFWE showed that it reduced the melanin index after 4 and 8 weeks, thereby confirming its skin-lightening effects. LFWE exerts excellent antioxidant effects and inhibits the expression of factors involved in melanin biosynthesis, thereby demonstrating skin-lightening effects. Moreover, LFWE-containing serum significantly reduced melanin indices in clinical trials.

Melanoma is an aggressive skin cancer with high metastatic potential and poor long-term survival, highlighting the need for new therapeutic targets. Although microRNAs are critical regulators of tumor progression, the function of miR-374b-5p in melanoma remains poorly understood. Here, we identify miR-374b-5p as a tumor suppressor in melanoma cells. We show that miR-374b-5p directly targets vascular endothelial growth factor C (Vegfc) and is associated with changes in mitogen-activated protein kinase (MAPK) signaling, accompanied by reduced levels of phosphorylated extracellular signal-regulated kinase (pERK) and tyrosinase (TYR). Consistent with these observations, miR-374b-5p overexpression suppresses melanoma cell proliferation, migration, and invasion in vitro. Conditioned media from miR-374b-5p-overexpressing melanoma cells is also associated with changes in macrophage-related inflammatory markers, suggesting that these alterations are consistent with a shift toward a more pro-inflammatory macrophage phenotype. In a mouse model, miR-374b-5p overexpression significantly reduced tumor growth and angiogenesis, and downregulated the lymphangiogenic factor VEGFC. Together, these findings identify miR-374b-5p as a novel regulator of melanoma progression that acts through VEGFC-associated MAPK signaling and tumor microenvironment reprogramming, identifying miR-374b-5p as a promising therapeutic candidate for melanoma.