Background: Hypoxic tumor microenvironment facilitate the process of tumor metastasis, and cancer cell and tumor-associated cells express and excreted more inducible tumor-growth and -metastasis factors under hypoxia. The main target of traditional anti-cancer drug focused on anti-cancer cell proliferation. But how to prevent cancer from the “help” provided by tumor-associated cells especially under hypoxia would be a new way in clinic.
DT-13, the saponin monomer of dwarf lilyturf tuber, effectively inhibited tumor metastasis under hypoxia in vitro and in vivo. Moreover, DT-13 exhibited stronger effect on anti-angiogenesis in endothelial cell and anti-cancer metastasis under hypoxia.
Aim: Considering the role of non-muscle myosin typeⅡA (NMⅡA) in cancer cell migration, and the anti-cancer and anti-angiogenesis effect of DT-13 under hypoxia, we would investigate whether DT-13 inhibits tumor metastasis on NMⅡA via tumor-associated cells under hypoxia.
Methods: Evaluating human lung cancer 95D cell proliferation by Brdu labeling assay; evaluating cell migration by would healing and Transwell assay; evaluating protein expression and location by Western blots and Immunofluorescence immunofluorescence separately; evaluating tumor-associated growth factors secreted by tumor associated cells by Enzyme-Linked ImmunoSorbent Assay (ELISA).
Results: Pre-treatment with DT-13 (0.1, 1, 10 μM), adipocyte and fibroblast hypoxia CM reduced 95D cell proliferation and migration in vitro compared with no-treatment hypoxia CM. hypoxia CM altered NMⅡA and Vinculin distribution, and down-regulated expression in 95D cell. Moreover, knocking-out NMⅡA induce the level of paxillin, p-paxillin, FAK, p-ERK1/2 and p-c-RAF. The CM pretreated with DT-13 could reverse the phenomenon. DT-13 also reduce the level tumor-associated growth factors (eg: Leptin, VEGF) secreted by adipocyte and fibroblast under hypoxia.
Conclusions: Under hypoxic tumor microenvironment, DT-13, hitting tumor-associated cells as a target, inhibited human lung adenocarcinoma growth and metastasis via changing the distribution and down-regulation expression of NMⅡA.