Periostin regulated by let-7/miR-98 family mediates the apoptosis and epithelial-mesenchymal transition of colon cancer / 中华肿瘤杂志

Objective@#To observe the expressions of periostin (Postn) in colon cancer tissues and cells, and to investigate its biological effect and mechanism in colon cancer cells.@*Methods@#Real-time quantitative polymerase chain reaction (RT-qPCR) and western blot were used to detect the expressions of Postn, let-7a and miR-98 in 20 pairs of colon cancer tissues and adjacent normal tissues, colon cancer cell lines including SW480, HT-29, HCT-116 and human normal colon epithelial cell NCM460. Small interfering RNAs (siRNAs) of Postn, pcDNA3.1-Postn plasmids, let-7a mimic and its negative control let-7a mimic-NC, miR-98 mimic and its negative control miR-98 mimic-NC were transfected into HCT-116 cells. 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) was used to detect cell viability. Flow cytometry was used to detect cell apoptosis. Luciferase reporter gene assay was used to determine the targeting relationship between miRNAs and Postn.@*Results@#Compared with adjacent normal tissues, Postn expression was up-regulated (P<0.05) while let-7a/miR-98 expression was down-regulated (P<0.05) in colon cancer tissues. Compared with NCM460 cells, Postn expression was up-regulated (P<0.05) while let-7a/miR-98 expression was down-regulated (P<0.05) in SW480, HT-29 and HCT-116 cells. In colon cancer tissues, the expression of Postn was negatively correlated with the expressions of let-7a and miR-98 (r=-0.69, P<0.001; r=-0.80, P<0.001). Inhibition of Postn in vitro reduced the viability of HCT-116 cells [(53.73±7.63)%, P<0.05], increased the apoptotic rate [(22.88±3.40)%, P<0.05], enhanced the expression of epithelial-mesenchymal transition (EMT) marker E-cadherin (2.44±0.39, P<0.05), while down-regulated the expressions of N-cadherin and Vimentin (0.44±0.07 and 0.38±0.06, P<0.05). Overexpression of Postn in vitro enhanced the cell viability of HCT-116 cells [(134.41±8.82) %, P<0.05], decreased the expression of E-cadherin (0.55±0.09, P<0.05), increased the expressions of N-cadherin and Vimentin (2.93±0.42 and 2.24±0.34, P<0.05), but had no effect on the apoptotic rate (P>0.05). Overexpression of let-7a or miR-98 partially reversed the biological effects of Postn overexpression in colon cancer cells, which implicated that Postn was a target gene of let-7a/miR-98.@*Conclusions@#Postn is a cancer-promoting molecule of colon cancer, and inhibition of Postn expression can increase the apoptotic rate of colon cancer cells and repress EMT. Postn expression and function is regulated by let-7a/miR-98.

MiR-145 inhibits drug resistance to Oxaliplatin in colorectal cancer cells through regulating G protein coupled receptor 98 / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To predict and identify the target gene of miR-145, and to explore the underlying mechanism of the inhibition of miR-145 on drug resistance to Oxaliplatin (L-OHP) in human colorectal cancer cells.</p><p><b>METHODS</b>L-OHP-resistant human colorectal cancer cell line (HCT116/L-OHP) was established in vitro by exposing to increased concentrations of L-OHP in cell culture medium. MiR-145-mimics and its negative control (NC-miRNA) were transfected into HCT116/L-OHP cells using liposome to establish HCT116/L-OHPover-expressing miR-145 and HCT116/L-OHP. The target genes of miR-145 were predicted by bioinformatic analysis, and validated by dual luciferase activity assay. After determination of G protein coupled receptor 98(GPR98) as target gene, corresponding plasmids were constructed and transfected to establish HCT116/L-OHPover-expressing GPR98 and HCT116/L-OHP. HCT116/L-OHP cells over-expressing both GPR98 and miR-145 (HCT116/L-OHP) were acquired through modification of the binding sites of GPR98 cDNA with miR-145. CCK-8 assay was used to assess the proliferation (A value) and sensitivity to L-OHP (the lower the IC50, the stronger the sensitivity) in HCT116/L-OHP cells. Real-time quantitative PCR was used to measure the mRNA expression of miR-145 and GPR98. Western blot was used to examine the protein expression of GPR98 and drug-resistant associated protein, such as P-glycoprotein (gp), multiple drug-resistance protein 1(MRP1), cancer-inhibition gene PTEN.</p><p><b>RESULTS</b>HCT116/L-OHP cell line was successfully established with ICof (42.34±1.05) mg/L and miR-145 mRNA expression of 0.27±0.04, which was higher than (9.81±0.95) mg/L (t=39.784, P=0.000) and lower than 1.00±0.09 (t=13.021, P=0.000) in HCT116 cells. Based on HCT116/L-OHP cells, HCT116/L-OHPcells were established successfully, with relative miR-145 expression of 10.01±1.05, which was higher than 1.06±0.14 in HCT116/L-OHPand 1.00±0.16 in HCT116/L-OHP (F=161.797, P=0.000). GPR98 was identified to be the target gene of miR-145. The relative mRNA and protein expressions of GPR98 in HCT116/L-OHPcells were 8.48±0.46 and 1.71±0.09, respectively, which were higher than those in HCT116/L-OHP(mRNA: 3.65±0.40, protein: 1.21±0.10) and HCT116/L-OHP (mRNA: 3.49±0.35, protein: 1.22±0.08; all P<0.05). The A value was 1.31±0.10, and the relative protein expressions of P-gp and MRP1 were 1.53±0.18 and 1.49±0.20 in HCT116/L-OHPcells, which were higher than those in HCT116/L-OHP (A value: 0.82±0.08, relative protein expression: 1.00±0.06 and 1.21±0.13, all P<0.05). The A value was 0.89±0.08, and the relative protein expressions of P-gp and MRP were 1.02±0.24 and 1.38±0.25 in HCT116/L-OHPcells, which were higher than those in HCT116/L-OHP(A value: 0.20±0.05, relative protein expression: 0.20±0.07, 0.55±0.10, all P<0.05). The relative protein expression of PTEN in HCT116/L-OHPcells was 0.12±0.03, which was lower than 1.25±0.14 in HCT116/L-OHP cells(P<0.05). In addition, relative protein expressions of P-gp and MRP1 were 1.02±0.24 and 1.38±0.25 in HCT116/L-OHPcells, which were higher than those in HCT116/L-OHPcells (0.20±0.07 and 0.55±0.10), while PTEN expression in HCT116/L-OHPcells was lower as compared to HCT116/L-OHPcells (1.41±0.16 vs. 1.98±0.13, P<0.05).</p><p><b>CONCLUSION</b>MiR-145 inhibits drug resistance to L-OHP of HCT116 cells through suppressing the expression of target gene GPR98.</p>

Detection and clinical significance of myeloid-derived suppressor cells in peripheral blood of patients with rectal carcinoma / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To study the expression of myeloid-derived suppressor cells (MDSC) in peripheral blood of patients with rectal carcinoma and to preliminarily explore its clinical significance.</p><p><b>METHODS</b>Blood samples from 76 rectal carcinoma patients who underwent surgery in Department of General Surgery, The Affiliated Cancer Hospital, Zhengzhou University between June and October 2013 were collected before operation, postoperative day 10 and 2 years after operation respectively. Flow cytometry was used to detect MDSC percentage in peripheral blood of 76 rectal carcinoma patients and 40 healthy people. The change of MDSC percentage in peripheral blood of rectal carcinoma patients after treatment was investigated. Furthermore, the relationship of peripheral blood MDSC percentage with clinicopathological characteristics was examined.</p><p><b>RESULTS</b>Preoperative MDSC percentage in peripheral blood of 76 rectal carcinoma patients [(3.52±0.68)%] was higher than that of 40 healthy people[(0.92±0.21)%], with significant difference (t=3.026, P=0.005). Preoperative MDSC percentage in peripheral blood of rectal carcinoma patients was significantly related with histological classification (t=2.453, P=0.018), depth of tumor invasion (t=2.051, P=0.035), lymph node metastasis (t=2.328, P=0.022), TNM stage (t=2.529, P=0.016). Univariate analysis showed that TNM stage, histological classification, lymph node metastasis, preoperative MDSC percentage in peripheral blood were the prognostic factors in rectal carcinoma. Multivariate analysis showed that TNM stage (HR=2.535, 95%CI: 0.851 to 4.160, P=0.038) and preoperative MDSC percentage in peripheral blood (HR=3.651, 95%CI: 0.877 to 14.263, P=0.031) were independent prognostic factors of rectal carcinoma. MDSC percentage in peripheral blood of rectal carcinoma patients decreased significantly on the postoperative 10-day [(2.41±0.46)%] compared to that before operation [(3.52±0.68)%], whose difference was statistically significant (t=1.778, P=0.043). During follow-up, tumor recurrence or metastasis was found in 23 patients. MDSC percentage in peripheral blood of rectal carcinoma patients with recurrence or metastasis [(4.37±1.23)%] was higher than that of rectal carcinoma patients without recurrence or metastasis [(2.36±0.35)%] two years after operation, with statistically significant difference (t=1.982, P=0.039).</p><p><b>CONCLUSIONS</b>MDSC percentage in peripheral blood of rectal carcinoma patients is significantly elevated compared to that of healthy people. Increased MDSC percentage indicates poor prognosis and tumor progression in rectal carcinoma patients. Measurement of peripheral blood MDSC percentage may have a potential clinical value in prognosis prediction of rectal carcinoma.</p>