Combination of nadroparin with radiotherapy results in powerful synergistic antitumor effects in lung adenocarcinoma A549 cells.

Low-molecular-weight heparins (LMWHs), which are commonly used in venous thromboprophylaxis and treatment, have recently been reported to have effects on cancer metastasis in pre-clinical research studies. This study was planned to define the synergistic antitumor effects of nadroparin (a kind of LMWH) combined with radiotherapy in A549 cells. Six experimental groups were set up in our study according to the different treatment: control group; irradiation (IR) group; low dose of nadroparin group (LMWH50, L50); high dose of nadroparin group (LMWH100, L100); LMWH50+IR group; LMWH100+IR group. The viability of A549 cells was assessed by Cell Counting Kit-8 (CCK-8) assay. The apoptosis of tumor cells was analyzed by flow cytometry (FCM) after treatment. The concentration of transforming growth factor-β1 (TGF-β1) in the culture supernatants was measured by enzyme-linked immunosorbent assay (ELISA). The migration and invasion of the A549 cells were tested by the Transwell chamber assay. The expression of survivin, CD147 and matrix metalloproteinase-2 (MMP-2) was analyzed by western blotting. CCK-8 assay showed that irradiation or nadroparin alone slightly inhibited the cell viability while the combined treatments significantly inhibited the cell viability in a dose- and time-dependent manner. The apoptosis rate showed greater improvement dose- and time‑dependently in the groups receiving combination therapy of nadroparin and irradiation than the control group or the group receiving nadroparin or irradiation alone by FCM. ELISA assay showed that the decreased TGF-β1 secretion was found after combined treatments with nadroparin and irradiation compared to either treatment alone. The Transwell chamber assay showed that nadroparin not only significantly suppressed the migration and invasion of A549 cells but also inhibited the enhanced ability of migration and invasion induced by X-ray irradiation. Western blotting showed that nadroparin inhibited the upregulated effects of survivin and MMP-2 expression induced by radiation in the combined treatment groups in a dose- and time-dependent manner. Moreover, the expression level of CD147 was the lowest in the combined treatment groups. This study identified that combination of nadroparin and irradiation had a strong synergistic antitumor effect in a dose- and time-related manner in vitro, which was reflected in the inhibition of cell viability, invasion and metastasis, promotion of apoptosis, inhibited secretion level of TGF-β1 and downregulation of CD147, MMP-2 and survivin expression.