The involvement of NK and other cytotoxic cells is considered the first defense' line against cancer. However, a significant lack of information prevails on the possible roles played by factors considered characteristic of primitive cells, such as c-kit and Sca-1, in activating these cells, particularly in melanoma models subjected to treatments with substances under investigation, such as the case of norcantharidin. In this study, B16F1 murine melanoma cells were used to induce tumors in DBA/2 mice, estimating the proportions of NK and iNKT cells, the presence of activation (CD107a+) and primitive/activation (c-kit+/Lya6A+) markers, some tumor parameters, such as the presence of mitotic bodies, nuclear factor area, NK and iNKT cell infiltration in the tumor, infiltrated tumor area, and infiltrating lymphocyte count at 10x and 40x in specimens treated with pentoxifylline, norcantharidin and the combination of both drugs. Possible correlations were estimated with Pearson's correlation analysis. Despite having demonstrated multiple correlations, it should be noted that immaturity/activation markers were related to these cells' activation. At the tumor site, iNKT cells are the ones that exert the cytotoxic potential on tumor cells, but they are confined to specific sites in the tumor. Due to the higher number of interactions of natural killer cells with tumor cells, it is concluded that the most effective treatment was PTX at 60 mg/kg + NCTD at 0.75 mg/kg.

Melanoma, one of the most aggressive forms of skin cancer, is also one of the most diagnosed cancer types. While surgical excision of the lesions is the primary treatment for melanoma, not all cases are candidates for surgical procedures. New treatments and complementary options are necessary, given the increasing diagnosis rate. In the present study, a norcantharidin-containing nanoemulsion was developed and evaluated in vivo using a syngeneic graft murine model. Our model contemplates an amputation surgery simulating the standard treatment and the role of the nanoemulsion as a potential adjuvant therapy. We observed a significant decrease in the growth rate of the melanoma lesion in the treated groups compared to the control group, both at the 20th and 30th days of treatment. Moreover, we evaluated the drug bioavailability in serum samples, and the results showed that norcantharidin was detectable in a range of 0.1 to 0.18 mg per mL in the treated groups. Furthermore, histopathological analysis was performed on the amputated tumors, where significant differences were found regarding size, mitosis rate, lymphocytic infiltration, and multispectral quantitative image analysis compared to the control group. The norcantharidin-containing nanoemulsion could be a potential alternative or adjuvant therapy if more clinical studies are conducted. Topical nanosystems can become or complement standard therapies, which is needed as melanoma affects not only in terms of mortality but also the patient's morbidity and life quality.

Disinfection by-products to obtain drinking water, such as CH2Cl2, CHCl3, and BrCHCl2, elicit cytotoxicity and hyperproliferation in human lung fibroblasts (MRC-5). Enzymes of their biotransformation modulate these damages and can generate toxic metabolites. However, it is unknown that the response to oxidative stress is involved in cellular hyperproliferation modulated by nuclear factor-kappa B (NF-κB). Hence, MRC-5 cells were treated with these compounds to evaluate ROS, lipid peroxidation, phospho-NF-κB/p65 (Ser536) levels, CAT, SOD, and GPx activities. Further, the interactions of halomethanes and ROS with IκBα/NF-κB/p65 complex were analyzed by molecular docking. The correlation among biomarkers showed positive relationships between the prooxidant damage with the antioxidant response, particularly in cells treated with CH2Cl2, and BrCHCl2. Furthermore, negative relationships among ROS with levels of NF-κB/p65 in cells treated with CH2Cl2, and CHCl3 were detected. The estimated relative free energy of binding using thermodynamic integration with the p65 subunit of NF-κB was -3.3 kcal/mol for BrCHCl2; -3.5 kcal/mol for both CHCl3 and O2•, and -3.6 kcal/mol for H2O2. The chloride and bromide are in close contact with the IPT domain residues, particularly in the RHD region involved in DNA binding. Ser281 is located in the same domain, allowing this protein's phosphorylation. Similarly, both ROS are in contact with IPT domain into region RHD and H2O2 as side-chain oxygen with Leu280, adjacent to the phosphorylation site of p65. However, a negative correlation among ROS with phospho- NF-κB/p65 suggests ROS's steric hindrance on the C-terminal domain of NF-κB/p65 is involved in antioxidant response.

3D cell cultures have improved the evaluation of drugs for cancer therapy, due to their high similarity to solid tumors. In melanoma, autophagy appears to show a dual role depending on the progression of the disease. p62 protein has been proposed for the evaluation of autophagic flux since its expression is an indicator of the state of autophagy. Pentoxifylline (PTX) and Norcantharidin (NCTD) are drugs that have been shown to have anticancer effects in various types of cancer. In this work, B16F1 mouse melanoma cell line was used, from which two-dimensional (2D) monolayer cultures and three-dimensional (3D) organoids were carried out using the hanging drop technique. The expression of p62 was determined by western blot and immunofluorescences. Our results indicate that pentoxifylline reduces p62 expression in both types of culture. While Norcantharidin increases its expression in 3D cultures at 24 h. Therefore, these drugs could have a potential therapeutic use for the regulation of autophagy in melanoma, depending on the state of evolution of the disease.