Objective To investigate the effects of down-regulating phosphorylated human epidermal growth factor receptor 2 (HER2) on the proliferation and metastasis in human osteosarcoma cells (U2-OS) in vitro. Methods Various concentrations of HER2 phosphorylation inhibitor lapatinib ditosylate (5, 10, 20, 30 and 40 μmol/L) were adopted to deal with U2-OS. MTT assay was performed to evaluate the cell proliferation during various times (24, 48 and 72 h), and the IC50 value in 24 h was calculated. The value of 10μmol/L (IC50=22.15μmol/L) was chosen to deal with U2-OS cells. The expres-sion level of phosphorylated HER2 (p-HER2) was measured by Western blot assay. The cell migration and invasion abilities were detected by Wound healing and Transwell invasion assays. Results The cell proliferation of U2-OS was significantly inhibited by HER2 phosphorylation inhibitor lapatinib ditosylate in a concentration- and time-dependent manner. During 24 hours, the p-HER2 level was significantly lower in lapatinib ditosylate group than that of negative control group (0.093± 0.033 vs 0.306±0.033), the cell migration rate was significantly lower in lapatinib ditosylate group than that of negative con-trol group (32.70%±3.00%and 94.52%±4.76%), and the trans-membrane cells were significantly lower than those of nega-tive control group (37/HP±5/HP and 85/HP±10/HP), respectively. Conclusion The down-regulating p-HER2 in U2-OS could efficiently inhibit the cell proliferation, migration and invasion in vitro. HER2 has the potential to become a molecular target for anti-osteosarcoma metastasis.

OBJECTIVETo observe the effects of electroacupuncture (EA) on pain behavior in rats with bone cancer pain and morphine tolerance, and to explore partial action mechanism.

METHODSForty-two SD healthy female rats were randomly divided into a sham operation group (7 rats), a bone cancer pain group (8 rats), a morphine tolerance group (9 rats), an EA group (9 rats) and a sham EA group (9 rats). The rats in the sham operation group were treated with injection of phosphate buffer saline at medullary cavity of left-side tibia, and the rats in the remaining groups were injected with MRMT-1 breast cancer cells. After operation, no treatment was given to rats in the sham operation group and bone cancer pain group. 11 days after operation, rats in the morphine tole-rance group, EA group and sham EA group were treated with intraperitoneal injection of morphine hydrochloride, once every 12 hours, for 11 days to establish the model of bone cancer pain and morphine tolerance. One day after the establishment of this bone cancer pain model, the rats in the morphine tolerance group were injected with morphine, once every 12 hours (9:00 a.m. and 9:00 p.m.) for 7 days; the rats in the EA group and sham EA group were injected with morphine at 9:00 a.m., and treated with EA (2 Hz/100 Hz) and sham EA (only injected into the subcutaneous tissue) at bilateral "Zusanli" (ST 36) and "Kunlun" (BL 60), 30 min per treatment, once a day for 7 days. One day before cancer cell injection, 6 days, 8 days, 10 days after operation, after 30 min on 1 days, 5 days, 9 days, 11 days of morphine injection, and after 30 min on 1 days, 3 days, 5 days, 7 days of EA treatment, the paw withdrawal threshold (PWT) was measured in each group. On 11 day of morphine injection, HE staining was applied to observe the morphology and structure change of tibia in the sham operation group, bone cancer pain group and morphine tolerance group, random 2 rats in each group. On 7 days of EA treatment, fluorescent immunohistochemical method was applied to observe the expression of μ-opioid receptor positive cells in nucleus ceruleus in each group, random 4 rats in each one.

RESULTSAfter 10 days of the cancer cells injection, the PWT of 28 rats of bone cancer pain model (8 rats in the bone cancer pain group, 8 rats in the morphine tolerance group, 6 rats in the EA group and 6 rats in the sham EA group) was significantly lower than that of 7 rats in the sham operation group (<0.01). After one day of morphine injection, the PWT of the morphine tolerance group, EA group and sham EA group was higher than that of the bone cancer pain group (all<0.01); on 11 d of morphine injection, the PWT of the morphine tolerance group, EA group and sham EA group was not significantly different from that of the bone cancer pain group (all>0.05). On 11 d of morphine injection, the tumor induced by cancer cells was observed in upper 1/3 tibia in the bone cancer pain group and morphine tolerance group, and the marrow cavity was filled with MRMT-1 cancer cells; no abnormal change was observed in the sham operation group. On 1 d, 3 d, 5 d and 7 d of EA treatment, the PWT of the cancer pain group, morphine tolerance group and sham EA group was lower than that of the EA group (all<0.01). On 7 d of EA treatment, the positive expression of MOR in nucleus ceruleus in the cancer pain group, morphine tolerance group, EA group and sham EA group was lower than that in the sham operation group (<0.01,<0.05), and that in the cancer pain group, morphine tolerance group and sham EA group was lower than that in the EA group (all<0.01).

CONCLUSIONSEA can improve mechanical pain threshold in rats with bone cancer pain-morphine tolerance, and improve the abnormal pain, which is likely to be involved with improvement of the MOR positive cells expression in nucleus ceruleus by EA.