Schizandrin A suppressed pancreatic cancer growth by inhibiting COX-2/ALOX5 shunting.

BackgroundSchizandrin A is major components extracted from Schisandra chinenzis-Turcz. Baill and Schisandra sphenanthear Rend. etWils. Schizandrin A exhibits remarkable hepatoprotective, antiviral and anti-inflammatory effects. However, the anti-tumor effects and its molecular mechanism were still known limited. MethodsThe affinity between Schizandrin A and COX-2/ALOX5 protein was analyzed using network pharmacology, computer molecular docking, and surface plasmon resonance experiments. Bioinformatic analysis and review of clinical characteristics were conducted to assess the necessity of simultaneous blocking of COX-2 and ALOX5 in pancreatic cancer (PC). LC/MS metabolomics and RNA-sequencing were utilized to investigate the effects of schizandrin A on the activation and expression of COX-2/ALOX5 in PC cells. Biological function experiments were conducted to investigate the inhibitory effects of Schizandrin A on PC cell proliferation and cancer-associated fibroblast activation in vitro and in vivo. ResultsSchizandrin A demonstrated a high affinity for binding directly with COX-2 and ALOX5, with kinetic association constants of 14.8 M and 21.8 M, respectively. PC exhibited a significant COX-2/ALOX5 signature, while PC cases with a high COX-2/ALOX5 signature showed lower overall survival and disease-free survival rates. Treatment of PC cells with schizandrin A resulted in decreased COX-2/ALOX5 activity and expression, leading to inhibition of leukotriene and prostaglandin production, as well as suppression of the downstream pathway NF-kappaB signaling. Schizandrin A demonstrated significant inhibitory effects on the proliferation and sphericity of PC cells in vitro, as well as on cell proliferation in vivo, while exhibiting low toxicity to normal tissues. Treatment of conditioned medium from PC cells with schizandrin A resulted in reduced induction of normal fibroblasts into cancer-associated fibroblasts. Furthermore, mutations in the binding sites of ALXO5 (Arg246) and COX-2 proteins (Ile124 and Ser126) resulted in a significant decrease in affinity to Schizandrin A, and blocking the inhibitory effects of schizandrin A. ConclusionsTaken together, schizandrin A directly bound with COX-2 and ALOX5, reduced their activation and leukotrienes and prostaglandins production, thus exhibiting distinguished effects on suppressing PC proliferation and inhibiting the ability of PC cell to induce normal fibroblasts to transform into tumor-associated fibroblasts. Therefore, schizandrin A represents a potentially novel therapeutic approach for PC.