Combined high energy of extracorporeal shock wave and 5-FU effectively suppressed the proliferation and growth of tongue squamous cell carcinoma.

BACKGROUND We tested the hypothesis that extracorporeal shock wave (ECSW)-assisted 5-FU therapy effectively suppressed human tongue squamous carcinoma cell line SAS (i.e., SAS cells) proliferation and tumor growth. METHODS AND RESULTS In vitro study showed that as compared with lower ECSW energy (≤0.12 mJ/mm2), higher ECSW energy (≥0.25-035 mJ/mm2) significantly suppressed the SAS cell proliferation and upregulated tumor cell apoptosis/DNA-damage/oxidative-stress, whereas combined higher ECSW energy (0.35 mJ/mm2) and 5-FU (20uM) further significantly altered the expressions of these parameters (all p < 0.001). Adult male nude mice (NM) (n = 36) were equally categorized into group 1 (2.0 × 105 SAS cells were implanted into NM back), group 2 [SAS in NM back + stepwise-increased ECSW energy (from 0.05/0.1/0.3/to 0.5 mJ/mm2)/500 impulses which applied to the tumor at days 9/12/15/21], group 3 (SAS in NM back + 5-FU/i.p./7 mg/kg/every 3-day) and group 4 (SAS in NM back + ECSW + 5-FU) and tumors were removed from each animal by day-28. The result showed that tumor volume and tumor weight were significantly progressively reduced from group 1 to group 4 (all p < 0.0001). The protein expressions of apoptotic (mitochondrial-Bax/cleaved-caspase3/cleaved-PARP/cyclophyllin-D), autophagic (ratio of LC3B-II/LC3B-I) and oxidative-stress (NOX-1/NOX-2) biomarkers displayed an opposite pattern of tumor mass among the groups, whereas the cell-stress signaling (p-PI3K/p-Akt/p-m-TOR, and ASK1/MKK4/MKK7/p38/p-JNK/p-c-JUN), MAP kinase family members (RAS/cRAF/KRAS/BRAF/p-ERK1/2), tumor protein (p53) and cellular levels of angiogenesis/DNA-damage (α-SMA+/VEGF+/γ-H2AX+) exhibited an identical pattern of tumor mass among the groups (all p < 0.0001). CONCLUSION Combined high-energy ECSW and 5-FU offers an additional benefit for suppressing the cancer cell proliferation and tumor growth.