siRNA targeting Livin decreases tumor in a xenograft model for colon cancer

AIM： To evaluate the effect of silencing Livin gene expression with siRNA to apoptosis and proliferation in a colon cancer cell line. METHODS： To investigate the anticancer effect of silencing Livin gene expression, we established an siRNA transfected cell line using the HCT116 colon cancer cell line. After confirming the successful transfection, MTT assay, flow cytometry and annexin V staining were em- ployed to evaluate the antiapoptotic effect. To confirm the in vivo effect of Livin-siRNA, different doses of LivinsiRNA were injected into xenografted tumors in BALB/c nude mice model. RESULTS： Livin expression was dramatically decreased after siRNA transfection, especially at 25 umol/L of siRNA, but this suppression was not dose-dependent. The cell count at 18 h after transfection was significantly reduced as compared with controls （P 〈 0.01）, but tended not to decrease proportionally depending on transfected dose or time. MTT assay revealed that silencing the Livin gene suppressed cellular proliferation at 18 h after transfection （P = 0.04）; however, the inhibitory effect disappeared thereafter. Also, there was no significant difference in cellular proliferation depending on siRNA dose. The rate of apoptosis also increased with silencing of the Livin gene. In vivo, the tumor size significantly decreased after Livin- siRNA injection at 20 umol/L concentration （P = 0.03）. There were no significant body weight changes of mice after siRNA injection. Histologic examination revealed no significant toxic reaction in kidney, liver and brain of mice. CONCLUSION： siRNA-mediated downregulation of Livin expression can induce apoptosis in colon cancer in vitro and in vivo, which suggests the possibility of new cancer therapeutics using siRNA.

Hemoglobin induces colon cancer cell proliferation by release of reactive oxygen species

AIM: To study whether hemoglobin could amplify colon cancer cell proliferation via reactive oxygen species (ROS) production. METHODS: Colon cancer cell line HT-29 was grown in the conventional method using RPMI1640 media. The viability of the cells was measured using the colorimetric MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazo- lium bromide] assay after adding hemoglobin. We de- termined reactive oxygen species levels to be indicators of oxidative stress in HT 29 cell lines with and without hemoglobin and/or 5-fluorouracil (5-FU), 5’-deoxy-5-flu- orouridine (5-DFUR) using fluorometric dichlorofluorescin diacetate (DCFH-DA) assay. RESULTS: Cellular proliferation was increased with he- moglobin in a concentration-dependent manner. A signif- icant increment on ROS levels was found in HT 29 cells following hemoglobin incubation. The cytotoxic effects of 5-FU and 5-DFUR were significantly blunted by admin- istration of hemoglobin. There was a slight increase of peroxiredoxin 1, superoxide dismutase 1 concentration according to different hemoglobin concentrations. CONCLUSION: Hemoglobin has a cellular proliferative effect on HT-29 colon cancer cell line by production of ROS. Also, hemoglobin abates cytotoxic effects of che- motherapeutic agents such as 5-FU and 5-DFUR.

Surgical outcomes of Korean ulcerative colitis patients with and without colitis-associated cancer

AIM: To determine the clinicopathologic characteristics of surgically treated ulcerative colitis(UC) patients, and to compare the characteristics of UC patients with colitis-associated cancer(CAC) to those without CAC. METHODS: Clinical data on UC patients who underwent abdominal surgery from 1980 to 2013 were collected from 11 medical institutions. Data were analyzed to compare the clinical features of patients with CAC and those of patients without CAC.RESULTS: Among 415 UC patients, 383(92.2%) underwent total proctocolectomy, and of these, 342(89%) were subjected to ileal pouch-anal anastomosis. CAC was found in 47 patients(11.3%). Adenocarcinoma was found in 45 patients, and the others had either neuroendocrine carcinoma or lymphoma. Comparing the UC patients with and without CAC, the UC patients with CAC were characteristically older at the time of diagnosis, had longer disease duration, underwent frequent laparoscopic surgery, and were infrequently given preoperative steroid therapy(P < 0.001-0.035). During the 37 mo mean follow-up period, the 3-yearoverall survival rate was 82.2%.CONCLUSION: Most Korean UC patients experience early disease exacerbation or complications. Approximately 10% of UC patients had CAC, and UC patients with CAC had a later diagnosis, a longer disease duration, and less steroid treatment than UC patients without CAC.