Effect of HDAC6 down-regulation on the growth of xenografted human laryngeal carcinoma cell line Hep-2 in nude mice and underlying mechanism / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To study the effect of histone deacetylation 6 (HDAC6) siRNA on the growth of xenografted human laryngeal squamous cell carcinoma cell line Hep-2 in nude mice and underlying mechanism.</p><p><b>METHODS</b>Laryngeal squamous cell carcinoma cell line Hep-2 cells were subcutaneously injected to the back of nude mice and transplanted tumor model was established after one week. Nude mice was divided into three groups including blank control group, empty vector group and HDAC6 siRNA group, and the tumor growth was observed. Ki-67 proliferation index was detected by immunohistochemistry. Western blot, in situ hybridization and immunohistochemistry were used to detect the mRNA and protein expressions of HDAC6 in xenograft. The expressions of Bcl-2 and Bax proteins were examined by Western blotting. Cell apoptosis was detected by TUNEL.</p><p><b>RESULTS</b>The mean volume of xenograft transfected with HDAC6 siRNA was less than that of xenograft transfected with empty vector or that of xenograft with blank control treatment (P < 0.05). HDAC6 siRNA effectively down-regulated the expressions of HDAC6 mRNA and the expressions of HDAC6 and Bcl-2 proteins, but up-regulated the expression of Bcl-2 protein in xenografts, with significant differences (all P < 0.05). The proliferation index of Ki-67 in HDAC6 siRNA transfection group was significantly lower than that in blank control group or empty vector group (P < 0.05). TUNEL assay demonstrated that HDAC6 evidently evoked cell apoptosis (P < 0.05).</p><p><b>CONCLUSION</b>HDAC6 siRNA could effectively inhibited the growth of xenografted human laryngeal carcinoma cell line Hep-2 in nude mice, down-regulate the expressions of HDAC6 and bcl-2, and up-regulate the expression of bax.</p>

Effects of downregulation of HDAC6 expression on cell cycle, proliferation and migration of laryngeal squamous cell carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To detect the expression of histone deacetylase 6 (HDAC6) in laryngeal squamous cell carcinoma, and to analyze the effects of downregulation of HDAC6 expression on cell cycle, proliferation and migration of laryngeal squamous cell carcinoma cell line Hep-2 cells, and to explore their possible molecular mechanisms.</p><p><b>METHODS</b>Immunohistochemistry was used to detect the expression of HDAC6 protein in 55 cases of laryngeal squamous cell carcinoma and 20 cases of normal laryngeal mucosa. HDAC6 siRNA and control siRNA were transfected into Hep-2 cells via lipofectamine 2000, and the interfering effect was analyzed using Western blotting. The effects of downregulation of HDAC6 expression on cell cycle, proliferation and migration were determined by cell counting kit-8 (CCK-8), flow cytometry and Boyden chamber, respectively. Finally, Western blotting was used to detect the expressions of cell cycle, proliferation and migration related proteins.</p><p><b>RESULTS</b>There was a high level expression of HDAC6 protein in laryngeal squamous cell carcinoma, and its expression was not related to age and sex of the patients (P > 0.05), but closely associated with the degree of histological differentiation, TNM staging and lymph node metastasis (P < 0.05). HDAC6 siRNA effectively down-regulated the expression of HDAC6 protein in laryngeal squamous cell carcinoma cell line Hep-2 cells, and downregulation of its expression obviously inhibited cell proliferation, arrested cell cycle at G(0)/G(1) phase and decreased cell migration ability in Hep-2 cells. Additionally, the downregulation of HDAC6 protein expression markedly decreased the expressions of cyclin D1, cyclin E, cdk2 and MMP-9 proteins, but increased the expressions of p21 and E-cadherin proteins.</p><p><b>CONCLUSIONS</b>HDAC6 may play a pivotal role in the carcinogenesis and development of laryngeal squamous cell carcinoma. The downregulation of HDAC6 expression-mediated cell proliferation inhibition, cell cycle arrest and decreased cell migration ability may be closely associated with the decrease of cyclin D1, cyclin E, cdk2 and MMP-9 proteins and increase of p21 and E-cadherin proteins.</p>

Down-regulation of histone deacetylase 2 induces cell apoptosis and inhibits cell proliferation and migration of laryngeal squamous cell carcinoma cells / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the effects of histone deacetylase 2 (HDAC2) expression on cell proliferation, apoptosis and migration of laryngeal squamous cell carcinoma (LSCC) Hep-2 cells.</p><p><b>METHODS</b>HDAC2 siRNA and control siRNA were transfected into LSCC Hep-2 cells by lipofectamine 2000, and cells were divided into three experimental groups: untreated group, control siRNA group and HDAC2 siRNA transfection group. Western blotting was utilized to detect the expression of HDAC2 protein in Hep-2 cells. Cell proliferation and apoptosis were investigated by CCK-8 kit and flow cytometry, respectively. Boyden chamber was used to study cell migration. Expressions of cell apoptosis and cell migration related proteins were detected by Western blotting.</p><p><b>RESULTS</b>HDAC2 siRNA significantly down-regulated the expression of HDAC2 protein in LSCC Hep-2 cells. Down-regulation of HDAC2 expression coincided with an inhibition of cell proliferation and migration along with an induced cell apoptosis of Hep-2 cells. Moreover, down-regulation of HDAC2 expression significantly increased the expressions of caspase-3 and caspase-9 proteins but decreased the expressions of matrix metalloproteinases (MMP)-2 and MMP-9 proteins.</p><p><b>CONCLUSIONS</b>HDAC2 may play a pivotal role in the initiation and development of LSCC. Down-regulation of HDAC2 expression mediates cell apoptosis. Cell migration inhibition may be tightly associated with overexpression of caspase-3 and caspase-9 along with down-regulation of MMP-2 and MMP-9 expressions.</p>

Inhibitory effects of small interfering RNA targeting c-myc in combination with 5-fluorouracil on the growth in vitro and in vivo / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To observe the effects of small interfere RNA (siRNA) targeting the c-myc in combination with 5-fluorouracil (5-Fu) on the growth of Hep-2 cells in vitro and in vivo.</p><p><b>METHODS</b>Hep-2 cells transfected with or without c-myc siRNA were treated with 5-Fu for 48 h. C-myc protein levels in Hep-2 cells were detected using the Western blot. The cell cycle was analyzed by flow cytometry. Hep-2 cells were subcutaneously inoculated into the back of BALB/c nude mice to establish the implanted laryngeal squamous carcinoma model. PBS, c-myc siRNA, and 5-Fu, alone or in combinations were administered i.p. The mice were sacrificed after the treatments and the tumor masses were removed to determine the tumor volume and weight. The inhibitory rate was calculated. Expression of c-myc in tumor tissue was detected by immunocytochemistry and cell apoptosis was analyzed by terminal transferase dUTP nick end labeling (TUNEL).</p><p><b>RESULTS</b>The protein levels of c-myc decreased after transfected with c-myc siRNA. C-myc siRNA-transfected cells showed an increase in the percentage of cells in the GO-G1 phase and a decrease in the percentage of cells in the S phase. When combined with 5-Fu, the results were improved. The tumor growth was faster in the control group and was significantly slower in the c-myc siRNA plus 5-Fu group than that in the c-myc siRNA group or 5-Fu group (P < 0.05). The tumor weight in the c-myc siRNA plus 5-Fu group was significantly smaller than that in the c-myc siRNA or 5-Fu group (P < 0.05). Immunohistochemistry showed that c-myc siRNA inhibited the expression of c-myc in tumor tissues in the c-myc siRNA group and c-myc siRNA plus 5-Fu group (P < 0.05). The number of apoptotic cells in the c-myc siRNA plus 5-Fu group was higher than those in the c-myc siRNA groups (P < 0.05).</p><p><b>CONCLUSIONS</b>C-myc siRNA inhibits the expression of c-myc in Hep-2 cells and in the tumor tissues of nude mice. C-myc siRNA combined with 5-Fu inhibits the growth of implanted laryngeal squamous carcinoma and promotes cell apoptosis. C-myc could become a novel target for the treatment of laryngeal squamous carcinoma.</p>