Interaction of SerpinB5 and MAFbx in gastric cancer cell and its action site / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To explore the interaction between SerpinB5 and MAFbx in gastric cancer cell and to identify the interaction sites.</p><p><b>METHODS</b>The interaction between SerpinB5 and MAFbx was screened and validated by yeast two-hybrid screening and co-immunoprecipitation. The expression of MAFbx was analyzed after SerpinB5 expression being modified by RNA interference and pGBKT7-SerpinB5 transfection. The impact of SerpinB5 on the expression of MAFbx was studied in gastric cancer cell line SUN-16. A model of MAFbx was constructed by homology modeling. The related residues for interaction were analyzed by Autodock4.0.</p><p><b>RESULTS</b>The interaction between SerpinB5 and MAFbx was validated. The expression of MAFbx changed along with SerpinB5 expression. Amino acids including PRO261, ASN361, and LYS362 were key residue in the interaction of SerpinB5 and MAFbx.</p><p><b>CONCLUSION</b>SerpinB5 interacts with MAFbx in gastric cancer cell. Amino acids including PRO261, ASN361, and LYS362 are potential binding sites.</p>

Knocking down osteopontin expression by specific siRNA reduces the in vitro invasiveness of human hepatocellular carcinoma cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the effect of osteopontin (OPN) expression down-regulated by RNA interference (RNAi) on the invasiveness of hepatocelluar carcinoma cell line HCC-LM3.</p><p><b>METHODS</b>HCC-LM3 cells were transfected with the chemically synthesized small interfering RNA (siRNA) formulated by lipofectamine 2000. Wild type HCC-LM3 and HCC-LM3 cells transfected with non-specific siRNA served as controls. Real-time PCR and Western blotting were used to quantify the mRNA and OPN protein levels. The malignant phenotypes of transfected HCC-LM3 cells including cellular growth rate, colony formation and Matrigel invasion activities were analyzed.</p><p><b>RESULTS</b>Sequence-specific siRNAs targeting OPN suppressed OPN RNA expression by 79% and also decreased OPN protein level by 81% in HCC-LM3 cells. The number of formed colonies and migrating numbers in vitro were decreased in HCC-LM3 cells transfected using sequence-specific siRNAs targeting OPN relative to controls (P < 0.05).</p><p><b>CONCLUSION</b>This study demonstrated that specific siRNA is able to reduce OPN at both the mRNA and protein levels and significantly diminishes the invasiveness of hepatocellular carcinoma cells.</p>