miR-320a suppresses colorectal cancer progression by targeting Rac1.

MicroRNAs (miRNAs) have emerged as critical epigenetic regulators involved in cancer progression. miR-320a has been identified to be a novel tumour suppressive miRNA in colorectal cancer (CRC). However, the detailed molecular mechanisms are not fully understood. Here, we reported that miR-320a inversely associated with CRC aggressiveness in both cell lines and clinical specimens. Functional studies demonstrated that miR-320a significantly decreased the capability of cell migration/invasion and induced G0/G1 growth arrest in vitro and in vivo. Furthermore, Rac1 was identified as one of the direct downstream targets of miR-320a and miR-320a specifically binds to the conserved 8-mer at position 1140-1147 of Rac1 3'-untranslated region to regulate Rac1 protein expression. Over-expression of miR-320a in SW620 cells inhibited Rac1 expression, whereas reduction of miR-320a by anti-miR-320a in SW480 cells enhanced Rac1 expression. Re-expression of Rac1 in the SW620/miR-320a cells restored the cell migration/invasion inhibited by miR-320a, whereas knockdown of Rac1 in the SW480/anti-miR-320a cells repressed these cellular functions elevated by anti-miR-320a. Conclusively, our results demonstrate that miR-320a functions as a tumour-suppressive miRNA through targeting Rac1 in CRC.

Clinical Significance of ß-Lactamase Expression in Colorectal Cancer.

Background: Colorectal cancer (CRC) has seriously endangered human health. Despite significant advances in clinical treatment of CRC in recent years, clinically effective treatment options for CRC patients remain rare. Therefore, reducing the incidence and mortality of CRC is still a worldwide concern. This study aims to explore the clinical significance of lactamase beta (LACTB)-like expression in CRC tissues. Materials and Methods: The expression of LACTB in CRC tissues and adjacent tissues in The Cancer Genome Atlas database was analyzed and the analysis results were verified by immunohistochemistry. The correlation between the expression level of LACTB and pathological factors and prognosis was analyzed. Results: There was statistical difference in the expression of LACTB in CRC tissues and adjacent tissues (p < 0.01). The expression of LACTB in CRC tissues was correlated with clinical stage (p < 0.01). The expression of LACTB in CRC patients with lymph node metastasis was significantly lower than that in CRC patients without lymph node metastasis (p < 0.01). Low expression of LACTB contributed to the poor prognosis of CRC patients. The 5-year survival rate of CRC patients with low LACTB expression was significantly lower than that of CRC patients with high LACTB expression (p = 0.010, p = 0.047). Conclusions: The expression of LACTB in CRC tissues was significantly lower than that in normal tissues, and it was significantly correlated with clinical prognosis, suggesting that LACTB could inhibit the CRC invasion and metastasis. This indicated to some extent that LACTB could be used as a prognostic marker and a new therapeutic target for CRC.

Salinomycin selectively targets 'CD133+' cell subpopulations and decreases malignant traits in colorectal cancer lines.

BACKGROUND: Cancer stem-like cells (CSCs) in colorectal cancers (CRC) may account for the failure of treatments because they are resistant to many current anticancer therapies. Salinomycin, a potassium ionophore, was recently identified as a selective inhibitor of breast CSCs. METHODS: The human CRC cell lines HT29 and SW480 were treated with salinomycin and oxaliplatin. Cell viability was determined with cell counting kit 8. Fraction of CD133+ cell subpopulations was assessed by Flow Cytometric analysis. Clonogenecity and migration were determined with soft agar and Boyden chamber assays. Molecular changes were assessed by immunofluorescence staining, RT-PCR, and Western blot analysis. RESULTS: We report that salinomycin reduces the proportion of CD133+ subpopulations in human CRC HT29 and SW480 cells. Furthermore, salinomycin treatment decreases colony-forming ability and cell motility in HT29 cells. Moreover, salinomycin downregulates the expression of vimentin and induces the E-cadherin expression in HT29 cells. CONCLUSIONS: This study demonstrates the ability of salinomycin to selectively target "CD133+" cell subpopulations and decrease the malignant traits in colorectal cancer lines.

TMPRSS4 correlates with colorectal cancer pathological stage and regulates cell proliferation and self-renewal ability.

Transmembrane protease/serine 4 (TMPRSS4) is a member of the type II transmembrane serine protease (TTSP) family and it was found highly expressed in several cancers. This study aims to evaluate the expression of TMPRSS4 in colorectal cancer (CRC) and investigate its role in proliferation and self-renewal of colon cancer cells. qRT-PCR and immunohistochemistry were used to detect the mRNA and protein expression level of TMRPSS4 in CRC samples respectively. Loss of function assay was conducted with RNAi technique. Cell proliferation was done with WST-8 assay; cell apoptosis and cell cycle analysis were performed with flow cytometry; invasion and migration were done with transwell assay. Plate and soft agarose clonogenic assays were used to detect clone-formation ability. CD44 and CD133 expressions were analyzed by flow cytometry and western blot. We found that TMPRSS4 was highly expressed in CRC tissues both at mRNA and protein level and correlated with pathological stage. Knockdown of TMPRSS4 in highly expressed colon cancer cell line HCT116 resulted in inhibition of cell proliferation, induction of cell apoptosis and suppression of invasion and migration; moreover, knockdown of TMPRSS4 suppressed the in vitro clone-formation ability of HCT116 and reduced the expressions of CD44 and CD133. The findings in this research showed that TMPRSS4 was associated with CRC stage and regulated the proliferation and self-renewal ability of colon cancer cells; TMRPSS4 was involved in the development and progression of CRC.

High expression of NEDD9 predicts adverse outcomes of colorectal cancer patients.

NEDD9, a member of Crk-associated substrate (CAS) family, is highly expressed in multiple cancer types and involved cancer cell adhesion, migration, invasion. The prognostic value of NEDD9 has not been evaluated before. The aim of this study was to evaluate the association between NEDD9 expression and survival in colorectal cancer (CRC) patients. NEDD9 expression was analyzed by immunohistochemistry in 92 patients with CRC. Patients were followed-up annually by telephone or at outpatient clinic. The results revealed that high expression of NEDD9 in 68/92 CRC samples, compared with 12/92 normal tissues (P<0.01). Correlation analysis showed high level of expression of NEDD9 was significantly correlated with advanced TNM stage (P=0.014), pT grade (P=0.009), pN (P=0.013) and pM status (P=0.047). Patients with a higher NEDD9 expression had a significantly shorter overall survival (OS) (P<0.01). The multivariate analysis revealed that NEDD9 expression could serve as an independent predictive factor of OS. Our finding demonstrated the potential value of NEDD9 expression level as a prognostic molecular marker and a target for new therapies for CRC patients.

High expression level of TMPRSS4 predicts adverse outcomes of colorectal cancer patients.

Transmembrane protease/serine 4 (TMPRSS4), a member of the type II transmembrane serine protease family, is highly expressed in some human cancers and involved in the EMT regulation of cancer cells. The prognostic value of TMPRSS4 in colorectal cancer (CRC) has not been discussed. This study aims to evaluate the association between TMPRSS4 expressions and survival in CRC patients. Immunohistochemistry revealed high expression of TMPRSS4 in 69/122 CRC samples, compared with 14/47 in normal tissues (P < 0.01). Correlation analysis showed high expression of TMPRSS4 was significantly associated with advanced TNM stage (P = 0.011), pT (P = 0.019), pN (P = 0.035), and pM status (P = 0.004). Higher TMPRSS4 predicted shorter overall survival (OS) and disease-free survival (DFS) in CRC patients (P < 0.01, both). Moreover, both TMPRSS4 expression and TNM stage were independent predictive factors of OS and DFS in Cox regression analysis. The findings in our study demonstrated the potential value of TMPRSS4 expression level as a prognostic biomarker for CRC patients.

Antitumor effects of hyperthermic CO2 pneumoperitoneum on human gastric cancer cells.

AIM: To elucidate the effects of hyperthermic CO2 pneumoperitoneum on human gastric AGS cells. METHODS: Based on a newly devised in vitro study model, we evaluated the anti-cancer effects of HT-CO2 (42-44 degrees C for 2-4h) on human gastric cancer cells, and also the corresponding mechanisms. RESULTS: HT-CO2 (42-44 degrees C for 2-4h) severely inhibited cell proliferation as assessed by Cell Counting Kit-8 assay, while inducing apoptosis in a temperature- and time-dependent manner demonstrated by annexin-V/PI flow cytometry and morphological analysis (Hoechst/PI fluorescence). In addition, it was found that HT-CO2 (42-44 degrees C for 2-4h) promoted the up-regulation of Bax by western blotting. Significantly, it could also suppress gastric cancer cell invasion and metastasis by in vitro invasion and motility assay. CONCLUSION: In conclusion, HT-CO2 had an efficacious cytotoxic effect on gastric cancer cells through Bax-induced mitochondrial apoptotic signaling. Our studies indicate that it may serve as a potential therapy for peritoneal carcinomatosis of gastric cancer. Further investigations in vivo using animal models are now urgently needed.

Suppression of colorectal cancer metastasis by nigericin through inhibition of epithelial-mesenchymal transition.

AIM: To evaluate the effect of nigericin on colorectal cancer and to explore its possible mechanism. METHODS: The human colorectal cancer (CRC) cell lines HT29 and SW480 were treated with nigericin or oxaliplatin under the conditions specified. Cell viability assay and invasion and metastasis assay were performed to evaluate the effect of nigericin on CRC cells. Sphere-forming assay and soft agar colony-forming assay were implemented to assess the action of nigericin on the cancer stem cell properties of CRC cells undergone epithelial-mesenchymal transition (EMT). RESULTS: Compared with oxaliplatin, nigericin showed more toxicity for the HT29 cell line (IC50, 12.92 ± 0.25 µmol vs 37.68 ± 0.34 µmol). A similar result was also obtained with the SW116 cell line (IC50, 15.86 ± 0.18 µmol vs 41.02 ± 0.23 µmol). A Boyden chamber assay indicated that a significant decrease in the number of HT29 cells migrating through polyvinylidene fluoride membrane was observed in the nigericin-treated group, relative to the vehicle-treated group [11 ± 2 cells per high-power field (HPF) vs 19.33 ± 1.52 cells per HPF, P < 0.05]. Compared to the control group, the numbers of HT29 cells invading through the Matrigel-coated membrane also decreased in the nigericin-treated group (6.66 ± 1.52 cells per HPF vs 14.66 ± 1.52 cells per HPF, P < 0.05). Nigericin also reduced the proportion of CD133+ cells from 83.57% to 63.93%, relative to the control group (P < 0.05). Nigericin decreased the number of spheres relative to the control group (0.14 ± 0.01 vs 0.35 ± 0.01, P < 0.05), while oxaliplatin increased the number of spheres relative to the control group (0.75 ± 0.02 vs 0.35 ± 0.01; P < 0.05). Nigericin also showed a decreased ability to form colonies under anchorage-independent conditions in a standard soft agar assay after 14 d in culture, relative to the control group (1.66 ± 0.57 vs 7 ± 1.15, P < 0.05), whereas the colony numbers were higher in the oxaliplatin group relative to the vehicle-treated controls (14.33 ± 0.57 vs 7 ± 1.15, P < 0.05). We further detected the expression of E-cadherin and vimentin in cells treated with nigericin and oxaliplatin. The results showed that HT29 cells treated with nigericin induced an increase in E-cadherin expression and a decrease in the vimentin expression relative to vehicle controls. In contrast, oxaliplatin downregulated the expression of E-cadherin and upregulated the expression of vimentin in HT29 cells relative to vehicle controls. CONCLUSION: This study demonstrated that nigericin could partly reverse the EMT process during cell invasion and metastasis.