Effect of siRNA targeting c-Myc and VEGF on human colorectal cancer cells / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the biological behavioral effects of specific siRNA expression plasmids targeted against c-Myc and vascular endothelial growth factor (VEGF) on human colorectal cancer cell line Volo.</p><p><b>METHODS</b>The expression plasmids with small interfering RNA (siRNA) aiming at c-Myc and VEGF were designed and constructed respectively, then transfected into Volo cells by eukaryocyte transfection technique. The protein expressions of c-Myc and VEGF were detected by Western blotting. Cellular proliferation, apoptosis, cycle distribution and invasion character were analyzed by tetrazolium bromide colorimetry (MTT), flow cytometry (FCM), TUNEL assay and matrigel invasion assay respectively.</p><p><b>RESULTS</b>Enzymatic digestion and DNA sequencing confirmed that the c-Myc and VEGF specific siRNA expression plasmids were constructed successfully. After plasmids were transfected into cells, the protein expressions of c-Myc and VEGF were significantly down-regulated respectively as compared with control group (P<0.01). The cellular proliferation inhibitory rates in c-Myc siRNA group, VEGF siRNA group and c-Myc+VEGF group were (59.20+/-5.05)%, (32.31+/-3.48)% and (75.81+/-7.89)% respectively, which were higher than that in control group [(6.80+/-1.45)%] (all P<0.05). The cell apoptosis rate in above 3 groups were (40.50+/-4.37)%, (21.30+/-2.98)% and (62.59+/-9.66)% respectively, which were higher than that in control group [(2.90+/-0.36)%] (all P<0.05). The cell invasion rates in VEGF siRNA group and c-Myc+VEGF siRNA group were (7.34+/-3.65)% and (2.80+/-1.02)%, which were lower than that in control group [(18.57+/-7.46)%] (P<0.05). The effect of c-Myc+VEGF siRNA group was greater.</p><p><b>CONCLUSIONS</b>The specific siRNA efficiently silences the expression of c-Myc and VEGF, subsequently, suppresses the cell proliferation, triggers the cell apoptosis and inhibits the cell invasiveness in these transfected colorectal cancer Volo cells. In addition, the synergism of siRNA-c-Myc and siRNA-VEGF in transfected cells can be found.</p>

Risk factors and the management of anastomotic leakage after anus-preserving operation for rectal cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the risk factors and management of anastomotic leakage after radical resection for rectal cancer and preservation of anal sphincter.</p><p><b>METHODS</b>The clinical data of 190 rectal cancer patients, undergone sphincter preserving procedures from Jan. 2004 to Jan. 2006, were analyzed retrospectively.</p><p><b>RESULTS</b>The incidence of anastomotic leakage among the 190 rectal cancer patients was 7.9% (15 patients). The leakage occurred from 2 to 17 days postoperatively and the average time of appearance was 5.8 days. Thirteen cases of anastomotic leakage were healed by conservative therapy. The treatment included nutritional support, catheter drainage of abdominal abscesses and the use of antibiotics. Healing time ranged from 10 to 60 days and the mean time was 21.8 days. The other 2 patients were healed by abdominal perineal resection and loop colostomy of transverse colon respectively. The complication of anastomotic leakage was associated with age (10.2% in older than 60 years versus 3.2% in younger than 60 years), physical status (20.7% in poor condition patients versus 5.6% in good condition patients), bowel obstruction (19.1% with obstruction versus 6.5% without obstruction), anastomotic procedure (12.2% in Parks' anastomosis versus 6.7% Dixon anastomosis), anastomotic location (9.2% for outside of peritoneal anastomosis versus 2.7 for inside of peritoneal anastomosis). The rates of anastomotic leakage in staple-line manual reinforce group and postoperative anorectal drainage group were significantly decreased than those in control groups (1.9% versus 11.4% and 2.9% versus 10.7%)(P<0.05).</p><p><b>CONCLUSIONS</b>Elderly patients, poor general condition, preoperative tumor obstruction, outside of peritoneal anastomosis are independent risk factors for the development of anastomotic leakage. Manual staple-line reinforce after stapled anastomosis and postoperative placement of drainage in rectum may be effective in decreasing the rate of anastomotic failure. Early and active conservative approach should be considered as the main treatment of anastomotic leakage.</p>