Sulfated Polysaccharide-Rich Fractions from Spirulina Platensis (SPPs) Exert Multi-Target Anticancer Activity in...

Background/Objectives: Sulfated polysaccharides from Spirulina platensis have shown various promising biological activities, but their anticancer effects in lung cancer models remain poorly characterized. In this study, sulfated polysaccharide-rich fractions (SPPs) were tested on A549 non-small cell lung cancer (NSCLC) cells to evaluate their cytotoxic, oxidative, and immunomodulatory activity. Methods: The potential of SPPs to interfere with A549 cell viability, to modulate intracellular reactive oxygen species (ROS) levels, to produce pro-inflammatory effects, and to induce apoptosis was evaluated. Co-administration experiments were also performed using Gefitinib, a drug commonly used in NSCLC therapy. Non-cancerous human bronchial epithelial cells (16HBE) were included to assess the ability of SPPs to selectively target tumoral cells. Results: Our findings show that SPPs significantly reduced A549 cell viability in a concentration-dependent manner and increased ROS levels. This effect was associated with apoptotic DNA fragmentation and modulation of apoptosis-related genes, including upregulation of BAX and CASP-9, and downregulation of BCL-2, MTOR, and BIRC5. SPPs also induced a controlled pro-inflammatory response by increasing ACE2, NF-κB1, and CCL2 expression while reducing COX-2 levels. In co-administration experiments with Gefitinib, a cancer drug used to treat NSCLC, enhanced cytotoxic and pro-apoptotic effects were observed. Importantly, at active concentrations (150-250 µg/mL) SPPs were not found to produce cytotoxicity or apoptosis in 16HBE cells. Conclusions: Overall, these findings suggest that SPPs may selectively target NSCLC cells by promoting redox imbalance, apoptosis, and immune response, without affecting healthy cells, supporting their potential as natural adjuvants in lung cancer treatment.