DT-13, a saponin monomer 13 of the Dwarf lilyturf tuber, synergized with vinorelbine to induce mitotic arrest via activation of ERK signaling pathway in NCI-H1299 cells.

Vinorelbine (NVB) is a semi-synthetic vinca alkaloid that is approved for the clinical therapy of lung cancer. However, the clinical application of NVB was limited because of the acquisition of resistance and inacceptable toxicity. Therefore, it is of great interest to develop low-cytotoxic drugs that can synergize with NVB. DT-13, a saponin monomer 13 of the Dwarf lilyturf tuber, showed inhibitory effects on tumor metastasis and angiogenesis in the previous studies. Here, we found that DT-13 combined with NVB exhibited synergistic effect to inhibit the cell proliferation in human lung cancer NCI-H1299 cells rather than human embryonic lung fibroblasts WI-38. The combination of DT-13 and NVB significantly inhibited the colony formation, induced cellular and nuclear morphological changes, and triggered cell cycle arrest at mitotic phase. Furthermore, MAPK signaling pathway was activated by the combination treatment, and the activation of ERK was required for the induction of mitotic arrest. Taken together, DT-13 combined with NVB exhibited synergistic anticancer effect in NCI-H1299 cells, and DT-13 may be a candidate agent for adjuvant chemotherapy of NVB in lung cancer.