Search Results (102)

To further extend the structure–activity relationships on previously identified anti-proliferative imidazo-pyrazoles, a novel series of compounds was designed and synthesized. In the obtained derivatives (1), the imidazo-pyrazole scaffold was formally condensed with a substituted triazole moiety, known for its biological properties. All derivatives were tested for anti-proliferative activity on a panel of 60 different cancer cell lines and compound 1h was identified as the most promising derivative, being highly effective against melanoma cells. Additional investigations demonstrated a cytotoxic and pro-oxidant action of the compound 1h on human metastatic melanoma cell lines (MeOV and MeTA) but not on healthy keratinocytes (HaCAT), confirming the selective activity of the compound. In silico calculations predicted favorable drug-like and pharmacokinetic properties and pre-formulation studies evaluated the effect of Tween 80 on 1h solubility. Overall, the collected data confirmed the pharmacological potential of the imidazo-pyrazole scaffold and indicated 1h as an interesting lead structure for the development of novel anti-melanoma agents. 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

Skin cancer, particularly melanoma, remains a major public health concern due to its high mortality rate. Current treatment options, including chemotherapy with dacarbazine and doxorubicin, have shown limited efficacy, achieving only a 20% objective response rate over six months, along with severe side effects such as cardiotoxicity. Given these limitations, there is a growing interest in herbal medicine as a source of novel anticancer compounds. Bambusa stenostachya, a bamboo species native to Taiwan, was investigated for its potential anti-melanoma properties using network pharmacology and molecular docking. LC-MS analysis identified seven bioactive compounds, including quinic acid and isovitexin, which satisfied Lipinski’s drug-likeness criteria. Among the seven bioactive compounds identified, five belong to the flavonoid family, while two are classified as phenolic compounds that modulate signaling pathways related to cancer and exhibit antioxidant activity, respectively. Through pathway enrichment analysis, four key melanoma-associated genes (PIM1, MEK1, CDK2, and PDK1) were identified as potential therapeutic targets. Ensemble docking results demonstrated that naringin-7-rhamnoglucoside exhibited the highest binding affinity (−6.30 kcal/mol) with phosphoinositide-dependent kinase-1, surpassing the affinities of standard chemotherapeutic agents. Additionally, the average docking scores for naringin-7-rhamnoglucoside and the remaining three proteins were as follows: PIM1 (−5.92), MEK1 (−6.07), and CDK2 (−5.26). These findings suggest that the bioactive compounds in B. stenostachya may play a crucial role in inhibiting melanoma progression by modulating metabolic and signaling pathways. Further in vitro and in vivo studies are necessary to validate these computational findings and explore the potential of B. stenostachya as a complementary therapeutic agent for melanoma. 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

Resistance to cell death is one of the core hallmarks of cancer, with regulatory abnormalities particularly pronounced in the malignant progression and therapeutic resistance of melanoma. This review aims to systematically summarize the roles and mechanisms of regulated cell death (RCD) in melanoma. Currently, distinct types of RCD, including apoptosis, autophagy, pyroptosis, immunogenic cell death, necroptosis, and ferroptosis, have all been found to be involved in melanoma. Autophagy promotes the survival of melanoma cells under stress conditions through metabolic adaptation, yet its excessive activation can trigger cell death. Immunogenic cell death has the capacity to elicit adaptive immune responses in immunocompetent syngeneic hosts. Necroptosis, governed by the receptor-interacting protein kinase 1 (RIPK1)/RIPK3 mixed lineage kinase domain-like protein (MLKL) signaling axis, can synergize with immunotherapy to enhance anti-melanoma immune responses when activated. Pyroptosis, mediated by Gasdermin proteins, induces the release of inflammatory factors that reshape the tumor microenvironment and enhance the efficacy of immune checkpoint inhibitors. Ferroptosis, characterized by lipid peroxidation, can overcome melanoma resistance by targeting the solute carrier family 7 member 11 (SLC7A11)/glutathione peroxidase 4 (GPX4) axis. Therapeutic strategies targeting RCD pathways have demonstrated breakthrough potential. Several agents have been developed to target RCD in order to suppress melanoma. Full article

Background and Objectives: Neuronal nitric oxide synthase (nNOS) overexpressed in melanoma plays a critical role in disease progression. Our previous studies demonstrated that nNOS inhibitors exhibited potent anti-melanoma activity and regulated PD-L1 expressions in the presence of interferon-gamma (IFN-γ). However, the role of nNOS in the melanoma immune response has not been well defined. Methods: Changes in gene expression profiles after nNOS inhibitor treatment were determined by transcriptomic analysis. A melanoma mouse model was used to determine the effects of nNOS inhibition on peripheral T cells and the in vivo anti-tumor activity of combining nNOS inhibitors with immune checkpoint blockade. Changes in human T cell activation through interleukin-2 (IL-2) production were investigated using an ex vivo co-culture system with human melanoma cells. Results: Cellular RNA analysis revealed significant changes in the genes involved in key signaling pathways after nNOS inhibitor HH044 treatment. Immunophenotyping of mouse peripheral blood mononuclear cells (PBMCs) after prolonged HH044 treatment showed marked increases in CD4⁺ and CD8⁺PD-1⁺ T cells. Ex vivo studies demonstrated that co-culturing human PBMCs with melanoma cells inhibited T cell activation, decreasing IL-2-secreting T cells both in the presence and absence of IFN-γ. PBMCs from a significant portion of donors (7/11, 64%), however, were reactivated by nNOS inhibitor pretreatment, displaying a significant increase in IL-2⁺ T cells. Distinctive T cell characteristics were noted at baseline among the responders with increased CD4⁺RORγt⁺ and reduced CD4 naïve T cells. In vivo mouse studies demonstrated that nNOS inhibitors, when combined with PD-1 blockade, significantly reduced tumor growth more effectively than monotherapy. Additionally, the median survival was extended from 43 days in the control mice to 176.5 days in mice co-treated with HH044 and anti-PD-1. Conclusions: Targeting nNOS is a promising approach to enhancing the anti-melanoma activity of immune checkpoint inhibitors, not only interfering with melanoma biological activities but also regulating the tumor microenvironment, which subsequently affects T cell activation and tumor immune response. Full article

Octocorals have proven to be a prolific source of bioactive natural products, exhibiting a wide spectrum of pharmacological activities. Among octocorals, Pennatulaceans, commonly known as sea pens, are among the most dominant soft coral species living in benthic communities. Nonetheless, reports on bioactivity and chemical investigations of this genus are scarce. This prompted us to shed light on the pharmacological potential of the extracts of the sea pen Pennatula phosphorea, Linneus 1758, and gain an overview of its metabolome. Crude octocoral extracts, obtained with a modified Kupchan extraction protocol, were assessed for their bioactivity potential, revealing the hexanic extract to exert anti-inflammatory effects and interesting protective properties in an in vitro model of sarcopenia and in auditory HEI-OC1 cisplatin-treated cells, while the chloroformic extract was active in reducing A375 melanoma cell viability in a concentration-dependent manner. An untargeted metabolomic analysis unveiled that P. phosphorea collects a wide array of glycerophospholipids and phosphosphingolipids belonging to the ceramide phosphoinositol class, which were exclusive or more abundant in the hexanic extract. Their proven anti-inflammatory and cytoprotective effects could demonstrate the activity shown by the P. phosphorea hexanic extract. In addition, a group of prostaglandins, eluted mainly in the chloroformic extract, were putatively annotated. Since prostanoids from marine origin have been demonstrated to exert cytotoxic and anti-proliferative properties against various cancer cell lines, the presence of PGs in the P. phosphorea chloroform extract could justify its anti-melanoma activity. This is the first report on the presence of glycerophospholipids, phosphosphingolipids, and prostaglandins, along with the identification of novel congeners, in sea pens. 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

Background and Objectives: Cutaneous melanoma (CM) poses a continuous challenge in oncology due to the developing resistance to available treatments. Doxorubicin (DOX) is noted as one of the most effective chemotherapeutics, although associated toxicity and resistance limit its use in CM treatment. Consequently, DOX has become a promising candidate for combination therapies targeting this neoplasm. Genistein (GEN) gathered significant attention due to its anti-neoplastic properties and ability to enhance the effects of DOX against several cancers, yet this association remains underexplored in CM. Therefore, this study investigated the combination therapy regimen comprising GEN and DOX in terms of anti-melanoma activity and safety profile. Materials and Methods: The in vitro experiments were performed on SK-MEL-28 and HaCaT cells. Cell viability was determined using MTT assay. Cell morphology and confluence were inspected microscopically. Nuclear and cytoskeletal aspects were assessed via immunofluorescence. Apoptosis and oxidative stress were quantified through caspase activity and intracellular reactive oxygen species (ROS) production, respectively. The irritant effect was evaluated on the chorioallantoic membrane. Results: The results revealed that the combination of GEN 10 µM with DOX (0.5 and 1 µM) provided augmented cytotoxic events (e.g., reduced cell viability, altered cell morphology and confluence, apoptotic-like impairments in nuclear shape and cytoskeletal network, increased caspases-3/7 and -9 activity, and elevated ROS) in SK-MEL-28 cells, compared to individual treatments, and exerted a strong synergistic interaction. Simultaneously, GEN 10 µM efficiently surpassed the toxic effects (e.g., viability and confluence loss, hypertrophy, and cytoskeletal condensation) of DOX (0.5 and 1 µM) in HaCaT cells. In ovo, GEN 10 µM + DOX 1 µM treatment was classified as non-irritant. Conclusions: These findings stand as one of the first contributions revealing the beneficial therapeutic interplay between GEN and DOX at physiologically achievable concentrations that resulted in elevated anti-tumor properties in CM cells and alleviated toxicity in keratinocytes. Full article

Melanoma is one of the most lethal cancers originating from melanocytes. Its incidence and mortality have been rising rapidly for several decades and have posed a serious threat to human health. Current melanoma treatments are hindered by the scope of application, low efficiency, high cost, and toxic side effects. Due to their affordability and minimal side effects, natural bioactive compounds derived from plants are promising candidates for melanoma treatment. This study aims to delve into the isolation, purification, and characterization of potato proteins and to explore their potential in melanoma treatment. Two potato proteins, patatin PP-1 and aspartate protease inhibitor PP-2, were isolated and purified by a newly developed method in this work, and their physicochemical properties were systematically characterized. Both potato proteins showed great antiproliferative activities and migration inhibition effects on melanoma cells. Meanwhile, Western blotting results illustrated that they could induce endogenous cell apoptosis by regulating the Bax/Bcl-2 pathway. Notably, aspartate protease inhibitor PP-2 demonstrated the best performance in inhibiting the growth and migration of melanoma cells, which might be attributed to the combined effect of its significant antioxidative activity and the inhibition effect of certain necessary protease activities in melanoma. This study provides valuable insights for developing nutraceuticals and therapeutic strategies against melanoma, which can lead to breakthroughs in melanoma treatment. Full article

Cutaneous melanoma (CM) is the most aggressive and fatal malignancy among other skin cancers and its incidence has risen steadily recently around the world. Hormone-related therapy, particularly estrogen (E2) has been used as a prospective strategy for CM treatment. Quercetin and luteolin are flavonoids with antitumor effects against a wide range of cancers including CM. However, the underlying mechanism of their actions through GPER in CM is not fully understood. We examined the anti-tumor effects of quercetin and luteolin on the A375 CM cell line through activation of the G-protein coupled estrogen receptor (GPER). MTT assay was performed to assess the impact of flavonoids on cell viability. Apoptosis and cell cycle were studied by flow cytometry. Cell migration was evaluated by transwell assay. GPER expression and the effect of the flavonoids on the key signaling proteins were confirmed by immunofluorescence staining and Western blot, respectively. Results showed that quercetin and luteolin inhibited proliferation and migration, induced apoptosis, and blocked the cell cycle at S and G2/M in A375 cells. Immunofluorescence and immunoblotting data demonstrated the presence of GPER in this cell line and the two flavonoids enhanced its expression except at the high concentration of 100 µM. Quercetin and luteolin enhanced P-ERK and c-Myc expression, an effect abolished by the GPER antagonist G15, confirming GPER-mediated signaling. In conclusion, quercetin and luteolin exhibited anti-tumor effects on A375 melanoma cells via GPER activation, suggesting their potential as anti-melanoma therapeutics. Full article

Background: In the present study, we aimed to characterize the cytotoxic efficacy of Zebularine either as a single agent or in combination with various isothiocyanates in an in vitro model consisting of human melanoma (A375, Colo-679) as well as non-tumorigenic immortalized keratinocyte (HaCaT) cells. Methods: In this model, we have evaluated the anti-melanoma effect of Zebularine (in single and combinatorial protocols) in terms of cell viability, apoptotic induction and alterations in ultrastructural chromatin configuration, protein expression levels of DNA methyltransferases (DNMTs) and associated histone epigenetic marks capable of mediating gene expression. Results: Exposure to Zebularine resulted in dose- and time-dependent cytotoxicity through apoptotic induction in malignant melanoma cells, while neighboring non-tumorigenic keratinocytes remained unaffected. A more profound response was observed in combinational protocols, as evidenced by a further decline in cell viability leading to an even more robust apoptotic induction followed by a differential response (i.e., activation/de-activation) of various apoptotic genes. Furthermore, combined exposure protocols caused a significant decrease of DNMT1, DNMT3A and DNMT3B protein expression levels together with alterations in ultrastructural chromatin configuration and protein expression levels of specific histone modification marks capable of modulating gene expression. Conclusions: Overall, we have developed a novel experimental approach capable of potentiating the cytotoxic efficacy of Zebularine against human malignant melanoma cells while at the same time maintaining a non-cytotoxic profile against neighboring non-tumorigenic keratinocyte (HaCaT) cells. Full article

(1) Malignant melanoma is the most aggressive type of malignant tumor caused by a dysfunction of melanocytes. Despite progress in the treatment of melanoma, further research and search for new potential drugs are necessary to optimize the therapy. (2) The aim of this study was to evaluate the antiproliferative activity of eight selected monoterpenes by MTT and LDH assays on four malignant melanoma cell lines. (3) Myrcene, rhodinol and nerol did not show any significant anticancer effect on melanoma cell lines, but citral, carvacrol, citronellol, thymol and geraniol showed a significant anti-viability effect. Our studies have shown that the most effective terpene among those tested in inhibiting melanoma cell viability was carvacrol, with the lowest IC50 in the range of 0.05 ± 0.00 to 0.06 ± 0.01 mM. Moreover, it did not negatively affect normal human keratinocyte cells. (4) Metastatic melanoma is very difficult to treat, and some terpenes have the ability to sensitize cells to other chemicals; so, it is worth investigating their antimelanoma potential, as terpenes could become an adjuvant to traditional treatment. Full article

Cutaneous melanoma (CM) is an aggressive and metastatic tumor, resulting in high mortality rates. Despite significant advances in therapeutics, the available treatments still require improvements. Thus, purinergic signaling emerged as a potential pathway to cancer therapy due to its involvement in cell communication, proliferation, differentiation, and apoptosis. In addition, due to safety and acceptable clinical tolerability, carotenoids from microalgae have been investigated as adjuvants in anti-melanoma therapy. Then, this work aimed to investigate the in vitro anti-melanogenic effect of carotenoid extract (CA) and total biomass (BM) of the Scenedesmus obliquus microalgae on two cutaneous melanoma cell lines (A375 and B16F10). Cells were cultivated under ideal conditions and treated with 10, 25, 50, and 100 μM of CA or BM for 24 h. The effects of the compounds on viability, oxidant status, and purinergic signaling were verified. The IC50 cell viability results showed that CA and BM decreased B16F10 viability at 24.29 μM and 74.85 μM, respectively and decreased A375 viability at 73.93 μM and 127.80 μM, respectively. Carotenoid treatment for 24 h in B16F10 and A375 cells increased the release of reactive oxygen species compared to the control. In addition, CA and BM isolated or combined with cisplatin chemotherapy (CIS) modulated the purinergic system in B16F10 and A375 cell lines through P2X7, A2AR, CD39, and 5′-nucleotidase. They led to cell apoptosis and immunoregulation by activating A2A receptors and CD73 inhibition. The results disclose that CA and BM from Scenedesmus obliquus exhibit an anti-melanogenic effect, inhibiting melanoma cell growth. Full article

Background/Objectives: The therapeutic management of melanoma, the most aggressive form of skin cancer, remains challenging. In the search for more effective therapeutic options, metal-based complexes are being investigated for their anticancer properties. Cisplatin was the first clinically approved platinum-based drug and, based on its success, other metals (e.g., gold) are being used to design novel compounds. Methods: the antimelanoma potential of a new organometallic cyclometalated Au(III) complex [[Au(C^NOxN)Cl₂] (C^NOxN = 2-(phenyl-(2-pyridinylmethylene)aminoxy acetic acid))] (ST004) was evaluated in vitro and in vivo. Furthermore, the gold-based complex was incorporated in liposomes to overcome solubility and stability problems, to promote accumulation at melanoma sites and to maximize the therapeutic effect while controlling its reactivity. The antiproliferative activity of ST004 formulations was assessed in murine (B16F10) and human (A375 and MNT-1) melanoma cell lines after 24 and 48 h incubation periods. The proof-of-concept of the antimelanoma properties of ST004 formulations was carried out in subcutaneous and metastatic murine melanoma models. Results: the developed liposomal formulations showed a low mean size (around 100 nm), high homogeneity (with a low polydispersity index) and high incorporation efficiency (51 ± 15%). ST004 formulations exhibited antiproliferative activity with EC₅₀ values in the μmolar range being cell-line- and incubation-period-dependent. On the opposite side, the benchmark antimelanoma compound, dacarbazine (DTIC), presented an EC₅₀ > 100 μM. Cell cycle analysis revealed an arrest in G0/G1 phase for Free-ST004 in all cell lines. In turn, LIP-ST004 led to a G0/G1 halt in B16F10, and to an arrest in S phase in A375 and MNT-1 cells. Preliminary mechanistic studies in human red blood cells suggest that gold-based inhibition of glycerol permeation acts through aquaglyceroporin 3 (AQP3). In a metastatic murine melanoma, a significant reduction in lung metastases in animals receiving LIP-ST004, compared to free gold complex and DTIC, was observed. Conclusion: This study highlights the antimelanoma potential of a new gold-based complex. Additional studies, namely in vivo biodistribution profile and therapeutic validation of this organogold complex in other melanoma models, are expected to be performed in further investigations. Full article