Chin Sheng Hung

Oncological and functional outcomes of intersphincteric resection for low rectal cancer

BACKGROUND The intersphincteric resection technique has been used to extend the opportunity for sphincter preservation in patients with very low rectal cancer. The aim of this study is to assess the long-term oncological and functional outcomes of intersphincteric resection. METHODS Patients with extraperitoneal rectal cancer were treated and retrospectively chart reviewed. The oncological and functional outcomes were evaluated. Comparisons of the overall disease-free survival and recurrence were analyzed for the different surgical procedures. RESULTS From July 2002 to August 2009, 162 patients with extraperitoneal rectal cancer were retrospectively chart reviewed. One-hundred one patients (62.3%) underwent low anterior resection, 26 patients (16%) received radical proctectomy and intersphincteric resection with coloanal anastomosis, and 23 (14.2%) had abdominoperineal resection. The sphincter preservation rate was 80%. In the intersphincteric resection group, overall survival rates at 3 and 5 y were 83% and 83%, and disease-free survival at 3 and 5 y were 82% and 76%, respectively. The mean stool frequency was 4.7 per 24 h. There were 38.1% of patients suffering from stool fragmentation, and 23.8% had nocturnal defecation. About one-third of the patients required antidiarrheal medications. Overall, 90.8% of patients were satisfied with the functional results of surgery. CONCLUSIONS Our data show intersphincteric resection for low rectal cancer is feasible and safe. Preoperative radiotherapy may negatively affect symptom-specific quality of life.

MicroRNA-200a/b influenced the therapeutic effects of curcumin in hepatocellular carcinoma (HCC) cells

MicroRNAs (miRNAs) play an essential role in regulating gene expression in normal and malignant cells. Expression of the microRNA-200 (miR-200) family has been correlated with malignancy in cancers. However, whether miR-200a/b plays a role in curcumin-mediated treatment of hepatocellular carcinoma (HCC) is unknown. We performed miRNA array analyses in two different HCC cell lines (HepG2 and HepJ5). The expression patterns of miR-200 family members were assessed with real-time PCR. We overexpressed miR-200 family members using a lentiviral system and selected stably transduced clones with antibiotics. The anticancer effects of curcumin on J5-200a, J5-200b, and J5-control cells were assessed by MTT assay, flow cytometry cell cycle analysis, and TUNEL assay. We found that HepG2 cells, which were more resistant to curcumin treatment than HepJ5 cells, expressed higher levels of miR-200a/b. The MTT assay revealed that the overexpression of miR-200a/b in HepJ5 cells conferred enhanced resistance to curcumin treatment compared with the control cells. By cell cycle analysis and TUNEL assay, we found that apoptosis was increased dramatically in J5-control cells compared with J5-200a and J5-200b cells after curcumin treatment. Finally, we evaluated the levels of Bcl-2, Bax, and Bad, and found a decrease of Bcl-2 levels and increase of Bad levels in the J5-control cells treated with curcumin. The expression levels of miR-200a/b might determine the therapeutic efficacy of curcumin on HCC cells.

Glucose-regulated protein 78 silencing down-regulates vascular endothelial growth factor/vascular endothelial growth factor receptor 2 pathway to suppress human colon cancer tumor growth.

BACKGROUND Up to 20% of colorectal cancer (CRC) is diagnosed with distant metastasis. The combination of chemotherapy with anti-vascular endothelial growth factor (VEGF) antibody can improve patient survival. Glucose-regulated protein 78 (GRP78) has an important role in cancer progression, but little is known about its role in VEGF production in CRC. The aim of this study was to explore the mechanism of GRP78 in two human colon cancer cell lines. METHODS We first checked the expression of GRP78 in human normal and colon cancer tissues and two colon cancer cell lines. Glucose-regulated protein 78 was knocked down using GRP78 small interfering RNA (siRNA) in HT29 and DLD-1 cells. We examined knockdown cells by the cell growth kinetics in vitro and tumor growth rate in vivo, respectively. We also investigated the effect of GRP78 siRNA on the expression of hypoxia inducible factor (HIF-1α), VEGF, and VEGF receptor 2 (VEGFR2). RESULTS Compared with their adjacent normal tissue, we detected high expression levels of GRP78 of surgically removed colon cancer tissues. Using GRP78 siRNA, we reduced the expression of GRP78 in HT29 and DLD-1 cells. The GRP78 knockdown cells had a lower proliferation rate with fewer colony-forming units in vitro and produced smaller tumors in vivo. In dissecting the mechanism underlying the reduced cell growth, we found that the down-regulation of GRP78 decreased the production of HIF-1α, VEGF, and VEGFR2 and suppressed angiogenesis. CONCLUSIONS Silencing GRP78 not only inhibits tumor, but also decreases the expression of VEGF and VEGFR2. Collectively, therapy targeting for GRP78 may inhibit the formation of colon cancer tumors via the HIF-1α/VEGF/VEGFR2 pathway.

Knockdown survivin expression reduces the efficacy of curcumin treatment in hepatocellular carcinoma cells

BackgroundSurvivin is a potential therapeutic target for cancer. Increased survivin expression promotes cell survival and therapeutic resistance. However, there is little information regarding whether the expression level of survivin affects curcumin treatment in hepatocellular carcinoma (HCC).MethodsSurvivin expression was suppressed in HCC cells using a short interfering RNA (siRNA) technique. The anticancer effects of curcumin were examined using a biosensor system, MTT assay, TUNEL assay, and cell cycle analysis.ResultsCurcumin resistance developed in cells with suppressed survivin, in contrast to the parental cells, as determined by survival assays. Cell cycle analysis and TUNEL assays revealed that the apoptotic cell population was increased in the scrambled-siRNA cells treated with curcumin compared with the survivin-siRNA cells. Suppression of survivin expression resulted in curcumin resistance via the modulation of Bcl-2 and Bax expression.ConclusionsWe conclude that the expression levels of survivin may mediate the therapeutic efficacy of curcumin in HCC cells.

Survivin-mediated therapeutic efficacy of gemcitabine through glucose-regulated protein 78 in hepatocellular carcinoma.

BackgroundSurvivin is an antiapoptotic molecule that is widely expressed in cancers, including hepatocellular carcinoma (HCC). Survivin has become a general therapeutic target for cancers because of its selective overexpression in a majority of tumors. However, little is known regarding the effect of survivin expression in combination with gemcitabine on HCC.MethodsWe generated survivin knockdown cells (survivin-KD) via a short interfering RNA (siRNA) technique. The antiproliferation effects of gemcitabine were determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling) assay, and cell cycle evaluation.ResultsAccording to the MTT assay, we found that survivin-KD cells were more sensitive than parental cells and scrambled control cells to gemcitabine treatment. The apoptotic cell population increased in survivin-KD cells that were treated with gemcitabine in comparison to scrambled control cells, as observed by the cell cycle distribution and TUNEL assays. We found that survivin knockdown resulted in a reduction of glucose-regulated protein 78 (GRP78), which may be responsible for the observed increased survivin-KD cell sensitivity to gemcitabine.ConclusionsWe conclude that survivin knockdown may contribute to a therapeutic effect of gemcitabine through GRP78 on HCC cells.

The α7-nicotinic acetylcholine receptor mediates the sensitivity of gastric cancer cells to taxanes

Gastric cancer is difficult to cure because most patients are diagnosed at an advanced disease stage. Systemic chemotherapy remains an important therapy for gastric cancer, but both progression-free survival and disease-free survival associated with various combination regimens are limited because of refractoriness and chemoresistance. Accumulating evidence has revealed that the homomeric α7-nicotinic acetylcholine receptor (A7-nAChR) promotes human gastric cancer by driving cancer cell proliferation, migration, and metastasis. Therefore, A7-nAChR may serve as a potential therapeutic target for gastric cancer. However, the role of A7-nAChR in taxane therapy for gastric cancer was unclear. Cells were subjected to A7-nAChR knockdown (A7-nAChR KD) using short interfering RNA (siRNA). The anti-proliferative effects of taxane were assessed via 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT), terminal deoxynucleotidyl transferase–mediated nick-end labeling (TUNEL), and cell cycle distribution assays. A7-nAChR-KD cells exhibited low resistance to docetaxel and paclitaxel treatment, as measured by the MTT assay. Following paclitaxel treatment, the proportion of apoptotic cells was higher among A7-nAChR-KD cells than among scrambled control cells, as measured by cell cycle distribution and TUNEL assays. Further molecular analyses showed a reduction in the pAKT levels and a dramatic increase in the Bad levels in paclitaxel-treated A7-nAChR-KD cells but not in scrambled control cells. Following paclitaxel treatment, the level of Bax was slightly increased in both cell populations, whereas Poly (ADP-ribose) polymerase (PARP) cleavage was increased only in A7-nAChR-KD cells. These findings indicate that A7-nAChR-KD cells are more sensitive to paclitaxel treatment. We conclude that A7-nAChR may be a key biomarker for assessing the chemosensitivity of gastric cancer cells to taxane.

Glucose-regulated protein 78 mediates the therapeutic efficacy of 17-DMAG in colon cancer cells

Glucose-regulated protein 78 (GRP78) is expressed as part of the molecular response to endoplasmic reticulum (ER) stress and mediates protein folding within the cell. GRP78 is also an important biomarker of cancer progression and the therapeutic response of patients with different cancer types. However, the role of GRP78 in the cytotoxic effect of 17-DMAG in colon cancer cells remains unclear. GRP78 expression was knocked down by small interfering RNA (siRNA). The anticancer effects of 17-DMAG were assessed by an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, a flow cytometric cell-cycle analysis, and an Annexin V-propidium iodide (PI) apoptotic assay. We found that HT-29 cells expressed a lower level of GRP78 compared with DLD-1 cells. The MTT assay revealed that HT-29 cells were more sensitive to 17-DMAG treatment than DLD-1 cells. GRP78 knock down (GRP78KD) cells demonstrated an increased sensitivity to 17-DMAG treatment compared with the scrambled control cells. Based on the cell-cycle analysis and Annexin V-PI apoptotic assay, apoptosis dramatically increased in GRP78KD cells compared with scrambled control DLD-1 cells after these cells were treated with 17-DMAG. Finally, we observed a decrease in the level of Bcl-2 and an increase in the levels of Bad and Bax in GRP78KD cells treated with 17-DMAG. These results are consistent with an increased sensitivity to 17-DMAG after knock down of GRP78. The level of GRP78 expression may determine the therapeutic efficacy of 17-DMAG against colon cancer cells.

Glucose-regulated protein 78 mediates the anticancer efficacy of shikonin in hormone-refractory prostate cancer cells

Glucose-regulated protein 78 (GRP78) is a key modulator of prostate cancer progression and therapeutic resistance. Prostate cancer is a worldwide health problem, and therapeutic resistance is a critical obstacle for the treatment of hormone-refractory prostate cancer patients. Shikonin inhibits prostate cancer proliferation and metastasis. However, the role of GRP78 in the cytotoxic effect of shikonin in prostate cancer cells remains unclear. GRP78 expression was abolished using small interfering RNA (siRNA), and the anticancer effects of shikonin were assessed using MTT assays, the XCELLigence biosensor, flow cytometric cell cycle analysis, and Annexin V-PI apoptotic assays. PC-3 cells expressed more GRP78 than DU-145 cells, and the MTT assays revealed that DU-145 cells were more sensitive to shikonin than PC-3 cells. GRP78 knockdown (GRP78KD) PC-3 cells were more sensitive to shikonin treatment than scrambled siRNA control cells. Based on cell cycle analysis and AnnexinV-PI apoptotic assays, apoptosis dramatically increased in GRP78KD cells compared with the control PC-3 in response to shikonin. Finally, in response to shikonin treatment, Mcl-1 and Bcl-2 levels increased in the scrambled control cells treated with shikonin, whereas Bcl-2 decreased and Mcl-1 slightly increased in the GRP78KD PC-3 cells. The levels of Bax and Bad did not change in the scrambled control or GRP78KD cells after shikonin treatment. These results are consistent with the increased sensitivity to shikonin after knockdown of GRP78. GRP78 expression may determine the therapeutic efficacy of shikonin against prostate cancer cells.

A polygenic risk score for breast cancer risk in a Taiwanese population

BackgroundMultiple common variants identified by genome-wide association studies showed limited evidence of the risk of breast cancer in Taiwan. In this study, we analyzed the breast cancer risk in relation to 13 individual single-nucleotide polymorphisms (SNPs) identified by a GWAS in an Asian population.MethodsIn total, 446 breast cancer patients and 514 healthy controls were recruited for this case–control study. In addition, we developed a polygenic risk score (PRS) including those variants significantly associated with breast cancer risk, and also evaluated the contribution of PRS and clinical risk factors to breast cancer using receiver operating characteristic curve (AUC).ResultsLogistic regression results showed that nine individual SNPs were significantly associated with breast cancer risk after multiple testing. Among all SNPs, six variants, namely FGFR2 (rs2981582), HCN1 (rs981782), MAP3K1 (rs889312), TOX3 (rs3803662), ZNF365 (rs10822013), and RAD51B (rs3784099), were selected to create PRS model. A dose–response association was observed between breast cancer risk and the PRS. Women in the highest quartile of PRS had a significantly increased risk compared to women in the lowest quartile (odds ratio 2.26; 95% confidence interval 1.51–3.38). The AUC for a model which contained the PRS in addition to clinical risk factors was 66.52%, whereas that for a model which with established risk factors only was 63.38%.ConclusionsOur data identified a genetic risk predictor of breast cancer in Taiwanese population and suggest that risk models including PRS and clinical risk factors are useful in discriminating women at high risk of breast cancer from those at low risk.