Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising chemotherapeutic agent because of its selective apoptotic action on cancer cells. However, resistance to TRAIL-induced apoptosis remains a challenge in many cancers. The gintonin-enriched Panax ginseng extract fraction (GEF) has diverse pharmacological benefits. We explored the combined efficacy of GEF and TRAIL in inducing apoptosis in human renal cell carcinoma (RCC) cells. The effect of GEF treatment on the viability, clonogenic potential, wound healing, and TRAIL-induced apoptotic signaling of RCC cells was studied in vitro. Our investigation revealed that GEF pre-treatment sensitized RCC cells to TRAIL-induced apoptosis, as evidenced by DNA fragmentation and cell proliferation, colony formation, and migration inhibition. This sensitization was linked to the upregulation of death receptors 4 and 5 and alterations in apoptotic protein expression, notably, the decreased expression of the Mu-2-related death-inducing gene, a novel anti-apoptotic protein. Our findings underscore the necessity of caspase activation for GEF/TRAIL-induced apoptosis using the pan-caspase inhibitor Z-VAD-FMK. This study demonstrates that GEF sensitizes human RCC cells to TRAIL-induced apoptosis by upregulating DR4/5 and modulating apoptotic protein expression. These findings suggest a promising strategy for overcoming TRAIL resistance in cancer therapy and highlight the potential of GEF as a valuable adjunct to TRAIL-based treatments.

Gintonin, a non-saponin glycolipoprotein from Panax ginseng, acts as a lysophosphatidic acid ligand. However, its anticancer effects, especially in melanoma, remain unclear. This study investigated the anti-proliferative effects and intracellular signaling mechanisms of a gintonin-enriched fraction (GEF) from Panax ginseng in human melanoma cell lines. In vitro, GEF treatment significantly inhibited cell proliferation, reduced clonogenic potential, and delayed wound healing in melanoma cells. Flow cytometry and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining showed that GEF induced apoptosis, as evidenced by increased apoptotic cell populations and nuclear changes. GEF also caused cell cycle arrest in the G₁ phase for A375 cells and the G₂/M phase for A2058 cells. It triggered apoptotic signaling via activation of caspase-3, -9, poly (ADP-ribose) polymerase cleavage, and downregulation of B cell lymphoma-2 (Bcl-2). GEF treatment also raised intracellular reactive oxygen species (ROS) levels and mitochondrial stress, which were mitigated by N-acetyl cysteine (NAC), an ROS inhibitor. In vivo, GEF suppressed tumor growth in A375- and A2058-xenografted mice without toxicity. These findings suggest that GEF from Panax ginseng has potential antitumor effects in melanoma by inducing apoptosis and cell cycle arrest, presenting a promising therapeutic avenue.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising chemotherapeutic agent because of its selective apoptotic action on cancer cells. However, resistance to TRAIL-induced apoptosis remains a challenge in many cancers. The gintonin-enriched Panax ginseng extract fraction (GEF) has diverse pharmacological benefits. We explored the combined efficacy of GEF and TRAIL in inducing apoptosis in human renal cell carcinoma (RCC) cells. The effect of GEF treatment on viability, clonogenic potential, wound healing, and TRAIL-induced apoptotic signaling of RCC cells was studied in vitro. Our investigation revealed that GEF pre-treatment sensitized RCC cells to TRAIL-induced apoptosis, as evidenced by DNA fragmentation and cell proliferation, colony formation, and migration inhibition. This sensitization was linked to the upregulation of death receptors 4 and 5 and alterations in apoptotic protein expression; notably, decreased expression of Mu-2-related death-inducing gene, a novel anti-apoptotic protein. Our findings underscore the necessity of caspase activation for GEF/TRAIL-induced apoptosis using the pan-caspase inhibitor Z-VAD-FMK. It demonstrates that GEF sensitizes human RCC cells to TRAIL-induced apoptosis by upregulating DR4/5 and modulating apoptotic protein expression. These findings suggest a promising strategy for overcoming TRAIL resistance in cancer therapy and highlight the potential of GEF as a valuable adjunct to TRAIL-based treatments.

Background/Objectives: Colorectal cancer (CRC) remains a major cause of cancer-related mortality worldwide, largely owing to metastasis, recurrence, and resistance to conventional therapies. Natural-product-derived compounds represent an important source of anticancer drug candidates. This study investigated the anticancer activity of purified narciclasine, which was tentatively annotated as a major detected constituent of Lycoris sanguinea extract, and examined its association with HELLS-associated DNA damage responses in CRC cells. Methods: Human CRC cell lines HT29 and HCT116 were used to evaluate the cytotoxic and mechanistic effects of L. sanguinea extract and narciclasine. Cell viability, clonogenic growth, apoptosis, mitochondrial membrane potential, cell cycle distribution, migration, and invasion were assessed. Western blotting was performed to analyze apoptosis-, cell cycle-, epithelial–mesenchymal transition (EMT)-, and DNA damage-related proteins. UPLC-QTOF/MS analysis was used to identify major phytochemical constituents. HELLS knockdown and γ-H2AX immunofluorescence staining were conducted to examine the involvement of HELLS in narciclasine-associated DNA damage and apoptosis. Results: L. sanguinea extract reduced CRC cell viability, suppressed clonogenic growth, induced mitochondrial dysfunction and caspase-dependent apoptosis, and promoted G2/M cell cycle arrest with decreased cyclin B1 and increased p53/p21 expression. The extract also inhibited migration and invasion, accompanied by reduced β-catenin, N-cadherin, vimentin, slug, and snail expression and increased E-cadherin expression. UPLC-QTOF/MS tentatively annotated narciclasine as a major detected constituent. Purified narciclasine recapitulated several anticancer effects of the extract, accompanied by HELLS downregulation, increased γ-H2AX accumulation, reduced cyclin B1 expression, and enhanced PARP and caspase-3 cleavage. HELLS knockdown further sensitized CRC cells to narciclasine-associated γ-H2AX accumulation, G2/M arrest-associated signaling, and apoptosis. Conclusions: Narciclasine treatment was associated with HELLS downregulation, DNA damage-associated signaling, G2/M cell cycle arrest-associated changes, EMT suppression, and apoptosis in CRC cells. These findings suggest that narciclasine is a promising natural-product-derived lead compound for further preclinical evaluation in HELLS-associated CRC vulnerabilities.