Abstract

BACKGROUND Bortezomib (BTZ) is ineffective in gastric carcinoma (GC) due to lysosome-mediated resistance. Wogonin derivative V8 targets lysosomes. AIM To address the limited efficacy of BTZ in GC and explore whether wogonin derivative V8 enhances anti-GC effects by overcoming lysosome-mediated resistance. METHODS In vitro experiments used four human GC cell lines (MGC-803, BGC-823, AGS, and HGC-27) to assess cell viability (cell counting kit-8), lysosomal function (LysoSensor staining), autophagy (western blotting for light chain 3/p62), and drug synergy [combination index (CI)]. Liquid chromatography/mass spectrometry measured intracellular BTZ concentration. Transcription factor EB (TFEB), a master regulator of lysosomal and autophagy genes, was investigated using small interfering RNA silencing and plasmid overexpression. In vivo efficacy/safety was tested in MGC-803 xenograft nude mice, and patient-derived tumor organoids (PDOs) validated clinical relevance. RESULTS BTZ was trapped in GC cell lysosomes, reducing its proteasome accessibility and inducing resistance; lysosome number correlated positively with the half-maximal inhibitory concentration of BTZ. V8 induced lysosomal damage/deacidification, increasing intracellular BTZ availability. V8 + BTZ synergistically inhibited GC cell growth (CI < 1), upregulated proteotoxic stress markers ( ATF4 , immunoglobulin heavy chain binding protein) and apoptotic mediators (cleaved caspase-3). TFEB knockdown enhanced V8 + BTZ cytotoxicity, whereas its overexpression reduced cell death, indicating a protective role of TFEB in gastric cancer cells. In xenografts, V8 + BTZ significantly reduced tumor volume/weight ( P < 0.01) without organ toxicity. PDOs showed enhanced sensitivity to V8 + BTZ vs monotherapy. CONCLUSION Lysosomes mediate BTZ resistance in GC; V8 overcomes this by disrupting lysosomes, enabling BTZ to target proteasomes. V8 + BTZ is a safe, effective strategy against GC.