Synergistic combination of DT-13 and topotecan inhibits human gastric cancer via myosin IIA-induced endocytosis of EGF receptor in vitro and in vivo

Abstract

Combination therapy has a higher success rate for many cancers compared to mono-therapy. The treatment of Topotecan (TPT) on gastric cancer (GC) is limited by its toxicity and the potential drug resistance. We found that the combination of the saponin monomer 13 from the dwarf lilyturf tuber (DT-13), performing anti-metastasis and anti-angiogenesis effects, with TPT synergistically induced apoptotic cytotoxicity in GCs with high EGF receptor (EGFR) expression, which was dependent on DT-13-induced endocytosis of EGFR. With TPT, DT-13 promoted EGFR ubiquitin--mediated degradation through myosin IIA-induced and Src/ caveolin-1 (Cav-1)-induced endocytosis of EGFR; inhibited EGFR downstream signalling and then increased the pro-apoptotic effects. Moreover, the synergistic pro-apoptotic efficacy of DT-13 and TPT in GCs with high EGFR expression was eliminated by both the NM II inhibitor (−)-blebbistatin and MYH-9 shRNA. The combination therapy of DT-13 with TPT showed stronger anti-tumour effects in vivo compared with their individual effects. Moreover, the results of combination therapy revealed selective upregulation of pro-apoptotic activity in TUNEL assays and cleaved caspase-3 and NM IIA in immunohischemical analysis; while specific downregulation of p-extracellular regulated kinase 1/2 (p-ERK1/2), EGFR and Cav-1 in immunohischemical analysis. Collectively, these findings have significant clinical implications for patients with tumours harbouring high EGFR expression due to the possible high sensitivity of this regimen.

Synergistic combination of DT‐13 and Topotecan inhibits aerobic glycolysis in human gastric carcinoma BGC‐823 cells via NM IIA/EGFR/HK II axis

“…NM IIA was essential for the endocytosis of EGFR and the modulation of the EGFR‐dependent activation of downstream signals, including ERK1/2 and AKT . In our previous research, we further confirmed the relationship of NM IIA and EGFR and that the ability of DT‐13 to enhance the pro‐apoptotic effect of TPT on GC via myosin IIA‐induced endocytosis of EGFR in vitro and in vivo . Meanwhile, it had been reported that EGFR signalling was also associated with increased glycolysis: activated the first step in glycolysis .…”

“…In our previous study, we had found that DT‐13 combined with TPT showed stronger antitumour effect in mice subcutaneous xenograft model in vivo compared with their individual effects . Here, we further evaluated the effect of DT‐13‐TPT combination in vivo using an established BGC‐823 cell orthotopic xenograft model.…”

“…As we found the inhibitory of combination treatment on aerobic glycolysis in vivo and in vitro, we desired to find out the potential mechanism. According to the finding that DT‐13 enhanced the pro‐apoptotic effect of TPT on GC via myosin IIA‐induced endocytosis of EGFR in vitro and in vivo, we wondered whether the combinational aerobic glycolysis inhibition effect was correlated to NM IIA. We first examined the relationship of NM IIA and aerobic glycolysis.…”

“…DT‐13, a saponin of the dwarf lilyturf tuber Ophiopogon japonicus wall (Family: Convallariaceae), possesses anticancer activities against various types of cancers and antiangiogenesis activity on multiple targets, such as early growth response 1 (Egr‐1), VEGF, CCR‐5, HIF‐1α and MMP2/9 . To increase the efficacy of TPT and avoid the risk of resistance development, we designed combination therapies of DT‐13 and TPT and found that DT‐13 enhanced the pro‐apoptotic effect of TPT on GC by up‐regulating NM IIA/EGFR/Cav‐1 axis …”

DT-13 synergistically enhanced vinorelbine-mediated mitotic arrest through inhibition of FOXM1-BICD2 axis in non-small-cell lung cancer cells

“…24 Apoptotic cells in tumor tissues were determined by TUNEL BrightGreen Apoptosis Detection Kit (Vazyme Biotech Co., Ltd), according to the manufacturer’s protocol.…”