Activación de los fibroblastos asociados al melanoma para superar la resistencia a los fármacos impulsada por células madre cancerosas

Acquired resistance to BRAF V600E inhibitors remains a major obstacle in melanoma treatment. We hypothesized that melanoma-initiating cells (MICs), regulated by cancer-associated fibroblasts (CAFs) in the tumor microenvironment, mediate drug resistance through stromal Notch1 signaling.

Patient-derived melanoma-associated fibroblasts (MAFs) were engineered to activate Notch1 signaling (MAF N1IC-GFP) via lentiviral transduction. Drug resistance was assessed using BRAF inhibitor-resistant melanoma cells (451LuBR) in 3D spheroid co-culture assays with PLX4720 treatment.In vivo efficacy was evaluated in NSG mice co-grafted with 451LuBR cells and MAF N1IC-GFP or control MAF GFP (n=8/group). Primary endpoints included tumor growth, angiogenesis, and CD271⁺ MIC populations assessed by immunofluorescence and quantitative imaging.

In vitro, MAF N1IC-GFP suppressed drug-resistant melanoma spheroid formation across PLX4720 concentrations (1-100 μM, P <0.01). In vivo, MAF N1IC-GFP co-grafting reduced tumor growth by 50% (mean tumor weight, P <0.01) and bioluminescence signal (P <0.05). Mechanistically, MAF N1IC-GFP selectively depleted CD271⁺ MICs (~50% reduction in fluorescence intensity, P<0.01), decreased their proliferation (P <0.01), and induced apoptosis (P <0.01).

Activating Notch1 signaling in melanoma-associated fibroblasts overcomes BRAF inhibitor resistance by disrupting cancer stem cell niches. This stromal-targeted approach represents a novel therapeutic strategy to complement surgical and systemic therapies in melanoma patients with drug-resistant disease.