Objective:To investigate the effect of Smac mimetic compound SM-164 on the radiosensitivity of cervical cancer cells and its underlying mechanisms.Methods:Human cervical cancer cell lines HeLa and SiHa were treated with different concentrations of SM-164 (0.05, 0.1, 0.2, 0.4 μmol/L) for 24 hours, followed by irradiation with 6 MV X rays at different doses (0, 2, 4, 6, 8 Gy). Clone formation assay was used to detect the survival fraction of HeLa and SiHa cells. The cells were divided into the negative control (NC) group, 4 Gy ionizing radiation (IR) group, 4 Gy combined with 0.2 μmol/L SM-164 treatment (IR+SM-164) group, and Caspases (Casp) broad-spectrum inhibitor Z-VAD blocking (IR+SM-164+Z-VAD) group. CCK-8 assay was adopted to assess cell proliferation, flow cytometry was used to detect cell apoptosis, and Western blot was employed to assess the changes in apoptosis-related proteins cleaved (C)-Casp9/Casp9, C-Casp3/Casp3, C-poly(ADP ribose) polymerase (PARP)/PARP, and DNA damage marker phosphorylated-histone H2A family member X (γH2AX)/H2AX ratios. One-way ANOVA was used for the comparison of means among multiple groups, and the SNK- q test was used for pairwise comparisons between two groups. Results:Compared with the NC group, the survival rates of HeLa and SiHa cells were significantly decreased after the combined treatment of IR and SM-164 (both P<0.01), and different concentrations of SM-164 enhanced cell radiosensitivity (all P<0.05). Compared with the NC group, cell proliferation activity was significantly decreased in the IR, IR+SM-164 and IR+SM-164+Z-VAD groups (all P<0.01), while apoptosis rate and the ratios of C-Casp9/Casp9, C-Casp3/Casp3, C-PARP/PARP, and γH2AX/H2AX were significantly increased (all P<0.01). Compared with the IR group, the proliferation activity in the IR+SM-164 group was significantly decreased ( P<0.05), whereas apoptosis rate and related protein ratios were significantly increased (all P<0.05). The γH2AX/H2AX ratio was increased in the IR+SM-164+Z-VAD group ( P<0.05). Compared with the IR+SM-164 group, the proliferation activity in the IR+SM-164+Z-VAD group was increased ( P<0.05), while the apoptosis rate and related protein ratios were significantly decreased (all P<0.05). Conclusion:SM-164 enhances the radiosensitivity of cervical cancer cells by inducing Casp activation.

Objective:To investigate the effect of Smac mimetic compound SM-164 on the radiosensitivity of cervical cancer cells and its underlying mechanisms.Methods:Human cervical cancer cell lines HeLa and SiHa were treated with different concentrations of SM-164 (0.05, 0.1, 0.2, 0.4 μmol/L) for 24 hours, followed by irradiation with 6 MV X rays at different doses (0, 2, 4, 6, 8 Gy). Clone formation assay was used to detect the survival fraction of HeLa and SiHa cells. The cells were divided into the negative control (NC) group, 4 Gy ionizing radiation (IR) group, 4 Gy combined with 0.2 μmol/L SM-164 treatment (IR+SM-164) group, and Caspases (Casp) broad-spectrum inhibitor Z-VAD blocking (IR+SM-164+Z-VAD) group. CCK-8 assay was adopted to assess cell proliferation, flow cytometry was used to detect cell apoptosis, and Western blot was employed to assess the changes in apoptosis-related proteins cleaved (C)-Casp9/Casp9, C-Casp3/Casp3, C-poly(ADP ribose) polymerase (PARP)/PARP, and DNA damage marker phosphorylated-histone H2A family member X (γH2AX)/H2AX ratios. One-way ANOVA was used for the comparison of means among multiple groups, and the SNK- q test was used for pairwise comparisons between two groups. Results:Compared with the NC group, the survival rates of HeLa and SiHa cells were significantly decreased after the combined treatment of IR and SM-164 (both P<0.01), and different concentrations of SM-164 enhanced cell radiosensitivity (all P<0.05). Compared with the NC group, cell proliferation activity was significantly decreased in the IR, IR+SM-164 and IR+SM-164+Z-VAD groups (all P<0.01), while apoptosis rate and the ratios of C-Casp9/Casp9, C-Casp3/Casp3, C-PARP/PARP, and γH2AX/H2AX were significantly increased (all P<0.01). Compared with the IR group, the proliferation activity in the IR+SM-164 group was significantly decreased ( P<0.05), whereas apoptosis rate and related protein ratios were significantly increased (all P<0.05). The γH2AX/H2AX ratio was increased in the IR+SM-164+Z-VAD group ( P<0.05). Compared with the IR+SM-164 group, the proliferation activity in the IR+SM-164+Z-VAD group was increased ( P<0.05), while the apoptosis rate and related protein ratios were significantly decreased (all P<0.05). Conclusion:SM-164 enhances the radiosensitivity of cervical cancer cells by inducing Casp activation.

Objective To investigate the role of high mobility group protein box 1 (HMGB1) in pulmonary vascular remodeling in a rat model of acute lung injury (ALI).Methods Thirty healthy pathogen free male Wistar rats weighing 220-250 g were randomly divided into 3 groups (n =10 each) ∶ group control (group C) ;group LPS (group M) and group LPS + HMGB1 antibody (group H).The animals were anesthetized with intraperitoneal 10％ chloral hydrate 7 ml/kg.ALI was induced with LPS 1 mg/kg infused iv over 30 min in groups M and H.In group H HMGB1 antibody 2 mg/kg was injected iv at 12,24 and 36 h after LPS administration respectively.The animals were sacrificed at 72 h after LPS administration.The left lung was removed for microscopic examination,measurement of the thickness of the medial layer (tunica media) of pulmonary arterioles and determination of the expression of PCNA (by immune-histochemistry) and HMGB1 protein (by Western blotting).Results The medial layer of pulmonary arterioles was significantly thicker and the expression of PCNA and HMGB1 higher in group M than in group C.LPS also induced significant inflammatory cell infiltration within the alveoli and damage to the septa.In group H HMGB1 antibody significantly attenuated the above-mentioned LPS-induced changes.Conclusion HMGB1 may play an important role in the LPS-induced pulmonary vascular remodeling.