Sodium valproate enhances doxorubicin cytotoxicity in breast cancer cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of sodium valproate, a histone deacetylase inhibitor, on the cytotoxicity of doxorubicin in breast cancer cells.</p><p><b>METHODS</b>Western blotting was used to assess Cx43 protein expression in breast cancer Hs578T cells exposed to doxorubicin and sodium valproate. MTT assay was used to determine the cytotoxicity of doxorubicin; annexin V/PI double staining and Hochest 33258 fluorescence staining were employed to detect doxorubicin-induced early and late apoptosis, respectively.</p><p><b>RESULTS</b>Western blotting showed that sodium valproate significantly increased Cx43 protein expression in Hs578T cells (P/0.01). The cells exposed to both sodium valproate and doxorubicin showed significantly lowered cell viability compared with the cells exposed to doxorubicin alone (P/0.01). Exposure to both sodium valproate and doxorubicin resulted in significantly increased early and late cell apoptosis rate compared with doxorubicin treatment alone (P/0.01).</p><p><b>CONCLUSION</b>sodium valproate can significantly enhance the cytotoxicity of doxorubicin and increase doxorubicin-induced apoptosis in breast cancer cells in vitro possibly by enhancing the gap junction function.</p>

Baicalein enhances the gap junction in the TM4 Sertoli cells of mice / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the effect of baicalein on the gap junction intercellular communication (GJIC) in the TM4 Sertoli cells of the mouse testis and its related mechanism.</p><p><b>METHODS</b>We measured the cytotoxicity of different concentrations of baicalein on the TM4 Sertoli cells in the mouse testis by MTT, detected the fluorescence transfer of the TM4 Sertoli cells by parachute assay, and determined the expression of the protein connexin 43 ( Cx43) in the baicalein-treated cells by Western blot and immunofluorescence assay.</p><p><b>RESULTS</b>Baicalein produced no obvious cytotoxicity on the TM4 Sertoli cells at the concentration below 60 µmol/L but significantly increased their GJIC at 0-20 µmol/L (P < 0.01). Western blot and immunofluorescence assay showed that 0-20 µmol/L baicalein remarkably elevated the expression of Cx43 in the TM4 cells (P < 0.01) and on the membrane of the TM4 cells.</p><p><b>CONCLUSION</b>Baicalein at the concentration of 0-20 µmol/L can significantly enhance GJIC in mouse TM4 Sertoli cells by increasing the expression of the Cx43 protein.</p>

PP2 enhances intercellular communication of gap junction in breast cancer Hs578T cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of Src kinase inhibitor PP2 on intercellular communication of gap junction in breast cancer cells.</p><p><b>METHODS</b>Cultured breast cancer Hs578T cells were treated with various concentrations of pp2 (0,1,2,4,8,16,32 μmol/L) for 24h. Cell growth was determined by MTT assay; dye spread in Hs578T cells was measured by Parachute assay; and the expression of Src kinase in Hs578T cells was detected by Western blot.</p><p><b>RESULTS</b>MTT assay showed that the survive rate of Hs578T cells treated with PP2 (1 ≊ 8 μmol/L) was 98% ± 3% ≊ 94 % ± 4%. Parachute assay showed that compared to control group the standard normalized dye spread rates of Hs578T cells treated with 1,2,4 and 8 μmol/L PP2 were 1.60 ± 0.08,2.00 ± 0.05,2.20 ± 0.05 and 2.70 ± 0.09,respectively (all P<0.01). Moreover,compared to control group at the same time points,the standard normalized dye spread of Hs578T cells treated with 8 μmol/L PP2 for 6,12 and 24 h were 1.4 ± 0.05,1.7 ± 0.06,and 2.2 ± 0.07,respectively (all P<0.01). Western blot showed that the expression ratios of Src kinase/β-actin of Hs578T cells treated with 1,2,4 and 8 μmol/L PP2 for 24 h were 0.93 ± 0.02,0.70 ± 0.09,0.66 ± 0.09 and 0.36 ± 0.10,which were significantly inhibited compared with control group (P<0.05 or 0.01). And the expression ratio of Src kinase/β-actin of Hs578T cells treated with 8 μmol/L PP2 for 6,12 and 24h was 0.82 ± 0.03,0.66 ± 0.08 and 0.59 ±0.09, which were all inhibited significantly compared to control group (P<0.01).</p><p><b>CONCLUSION</b>PP2 enhances the gap junction function in breast cancer Hs578T cells, which is probably related to the inhibition of Src kinase.</p>

Influence of Cx26/Cx32 gap junction channel on antineoplastic effect of etoposide in Hela cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the influence of Cx26/Cx32 gap junction channel on the antineoplastic effect of etoposide in Hela cervical cancer cells.</p><p><b>METHODS</b>Fluorescence trace was used to assay the gap junction intercellular communication mediated by Cx26/Cx32 in Hela cells and its functional modulation by the pharmacological agents (oleamide, retinoid acid). A standard colony-forming assay was applied to determine the cell growth-inhibiting effect of etoposide in Hela cells with functional modulation of the gap junction. Hoechst 33258 staining was used to assess the changes in etoposide-induced apoptosis of Hela cells with altered gap junction functions.</p><p><b>RESULTS</b>Oleamide markedly decreased while retinoid acid obviously increased the gap junction function in Hela cells. Standard colony-forming assay showed that etoposide produced a lowered antiproliferative effect in Hela cells with reduced gap junction and an increased antiproliferative effect in cells with enhanced gap junction function. In cells with a reduced gap junction function, etoposide induced a lowered apoptosis rate, which increased obviously in cells with an enhanced gap junction function.</p><p><b>CONCLUSION</b>The antineoplastic effect of etoposide is reduced in Hela cells with a decreased gap junction intercellular communication mediated by Cx26/Cx32 and is enhanced in cells with an increased gap junction intercellular communication.</p>

Cross-sectional study on falls in residents of four communities in Zhejiang Province, China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To understand the incidence of falls in different residents of four communities in Zhejiang Province to provide a basis for their prevention and control.</p><p><b>METHODS</b>A household questionnaire survey on falls was conducted in 16 899 residents of two urban and two rural communities during November 2000 to October 2001.</p><p><b>RESULTS</b>Standardized incidence rate of falls was 5.07%, higher in rural areas (5.23%) than that in urban areas (4.95%) and showing no significant differences by gender. Falls occurred in September and October accounted for 11.68% and 19.22% and those occurred in pre-school children and the elderly accounted for 22.94% and 19.46% of the total episodes, respectively. Leading causes of falls varied in different population, from falls during their play (7.65%) and sports (4.06%) in young people and pre-school children (19.12%), slipping down when walking in adult (1.21%) and elderly (4.28%) men, and slipping down when up and down stairs in adult and elderly women. Burden and severity of injury caused by falls were increased with age.</p><p><b>CONCLUSIONS</b>Incidence of falls in pre-school children and the elderly was higher in local residents of communities in Zhejiang Province, causing heavy burden to the society and their families. Varied relevant measures should be taken to prevent and control for falls in different subgroups of population.</p>