Estudo in silico, in vitro e in vivo de um novo derivado de xanteno com potencial antimelanoma

Abstract

Melanoma is the most aggressive and lethal form of skin cancer, characterized by metastatic processes. Despite therapeutic advancements, such as targeted therapy and immunotherapy, challenges related to treatment resistance persist. Recent studies suggest that xanthene derivatives may represent promising therapeutic options for melanoma due to their structure, which allows the incorporation of chemical groups capable of triggering therapeutic activities. This study aimed to evaluate the antimelanoma potential of a novel xanthene derivative, PD01, using in silico, in vitro, and in vivo approaches. Virtual screening was performed using molecular docking techniques to assess the interaction affinity between PD01 and the reference drug vemurafenib. The pharmacokinetic parameters of PD01 were analyzed through the SwissADME platform. The physicochemical characterization of PD01 was conducted using Nuclear Magnetic Resonance (NMR) and Infrared (IR) absorption spectrophotometry. Thermogravimetric (TGA) and Differential Scanning Calorimetry (DSC) assays were performed to investigate the thermal stability of PD01. In vitro assays were conducted on three cell lines: human melanoma (SK-MEL-28), murine melanoma (B16-F10), and human fibroblasts (MRC-5), with cytotoxicity evaluated by the Alamar Blue method. Cell morphology was analyzed using a rapid panotic staining kit, and the type of cell death was assessed by differential staining with acridine orange and ethidium bromide. PD01 was tested in a murine melanoma in vivo model and compared to the positive control (doxorubicin) for tumor growth inhibition evaluation. Histological analysis was performed to assess organ integrity. In the virtual screening, PD01 showed better interaction affinity (-11.1 kcal/mol) compared to the reference drug vemurafenib (-9.204 kcal/mol), also indicating a lipophilic profile. NMR and IR spectrophotometry analyses revealed that PD01 possesses a defined molecular structure. TGA and DSC assays showed a mass loss of 57.72% between 26 and 600 ºC, with peaks observed at 60.2 ºC and 299.47 ºC. The molecule was cytotoxic, with IC50 values of 5.07 ± 1.28 μM for SK-MEL-28, 18.85 ± 3.28 μM for B16-F10, and 4.94 ± 0.72 μM for MRC-5. Morphological analyses revealed that PD01 induced cell death through apoptosis, with apoptotic and necrotic cells observed, particularly at the 10 μM concentration. In the murine melanoma in vivo model, PD01 was less effective than doxorubicin, with tumor growth inhibition of 5.96% and 10.16% at doses of 3 mg and 30 mg, respectively, while doxorubicin achieved 29.49%. Histology of the organs did not show significant damage, suggesting that PD01, with optimized doses, could yield better therapeutic outcomes. In conclusion, the xanthene derivative PD01 exhibited cytotoxic activity against melanoma cells, inducing apoptosis, with promising results in preliminary studies. However, its efficacy in in vivo models was inferior to conventional treatments. Future studies should improve its formulation, solubility, and bioavailability to enhance its therapeutic effects and facilitate clinical trials.