Prognostic implications of SLIT and ROBO1 expression in gallbladder cancer

ROBO1 protein expression is independently associated with biochemical recurrence in prostate cancer patients who underwent radical prostatectomy in Asian patients

Background

The purpose of this study is to investigate the correlation between ROBO1 expression and prostate cancer aggressiveness.

Methods

ROBO1 expression was evaluated in normal prostate epithelial cells (PrEC) and different prostate cancer cell lines by Western blot analysis. The migration and invasion of native and ROBO1 knockdown cells were evaluated using migration chambers and a Matrigel-coated membrane, respectively. Samples from 145 patients who underwent radical prostatectomy between June 2000 and June 2008, were retrieved from the paraffin files for tissue microarray (TMA) with immunohistochemical analysis. Biochemical recurrence (BCR)-free survival curves were estimated using the Kaplan-Meier and Cox regression methods in two groups of patients classified according to the degree of ROBO1 expression (low or high expression).

Results

ROBO1 is highly expressed in the prostate cancer cell lines. All ROBO1 knockdown cells (PC3, 22Rv1 and DU 145) showed markedly decreased migration and invasiveness compared to native cells. In 145 patients with radical prostatectomy, the Kaplan-Meier curves and log-rank test for BCR-free survival stratified by ROBO1 expression in organ-confined (pT2) or not (pT3), showed significant differences in 10-year survival between the ROBO1 high and low expression groups (87.2% versus 52.6% in pT2; P=0.047, 51.0% versus 36.9% in pT3; P=0.033). The multivariable-adjusted model showed a markedly increased hazard ratio (HR) in patients with high ROBO1 expression compared to the patients with low ROBO1expression in every model.

Conclusions

ROBO1 may play an important role in the migration and invasion of prostate cancer cells, and was independently associated with BCR.

Downregulation of miR-181b-5p Inhibits the Viability, Migration, and Glycolysis of Gallbladder Cancer by Upregulating PDHX Under Hypoxia

Background

Gallbladder cancer (GBC) is a malignant cancer with poor prognosis. Evidences have shown that miRNAs are closely related to the occurrence of GBC; thus, we aimed to explore miRNAs, which plays an important role in the occurrence and development of GBC.

Methods

Microarray analysis was performed to investigate the differentially expressed miRNAs between five non-neoplastic gallbladder tissues (normal tissues) and five gallbladder tumor tissues (tumor tissues). RT-qPCR was performed to detect the level of miR-181b-5p in cells, and CCK-8 was performed to detect cell viability. Then, glucose assay kit or lactic acid assay kit was performed to detect the level of glucose consumption or lactate production. Next, transwell and wound healing assays were used to assess cell migration. In addition, dual-luciferase reporter assay was used to verify the relationship between miR-181b-5p and PDHX. At last, Western blotting was performed to determine the protein level of PDHX.

Results

Microarray analysis suggested miR-181b-5p was significantly upregulated in GBC tumor tissue. KEGG analysis for the protein targets of miR-181b-5p indicates a close relationship existed between miR-181b-5p and glycolysis. In addition, the level of miR-181b-5p was notably increased in GBC-SD or G415 cells, compared with HIBEpiC cells. GBC cell viability was significantly decreased under hypoxia, and these decreases were exacerbated by miR-181b-5p antagomir. Moreover, glucose consumption or lactate production of GBC cells was significantly upregulated under hypoxia, whereas these increases were completely revered by miR-181b-5p antagomir. Further investigation revealed that PDHX was a direct target of miR-181b-5p.

Conclusion

In this study, downregulation of miR-181b-5p inhibits the viability, migration, and glycolysis of GBC by upregulating PDHX under hypoxia. This finding suggested that miR-181b-5p might be considered as a novel therapeutic target for the treatment of GBC.

Robo1 promotes angiogenesis in hepatocellular carcinoma through the Rho family of guanosine triphosphatases' signaling pathway

Robo1 is a member of the Robo immunoglobulin superfamily of proteins, and it plays an important role in angiogenesis and cancer. In this study, we investigate the role of roundabout 1 (Robo1) in tumor angiogenesis in hepatocellular carcinoma (HCC). Firstly, the relationship between Robo1 expression on tumors and patient's survival and endothelial cells in tumor blood vessels and patient's survival was studied. Secondly, Robo1 was overexpressed or knocked down in human umbilical vein endothelial cells (HUVECs). Cell proliferation, motility, and tube formation were compared in HUVEC with different Robo1 expression. Also, HUVECs with different Robo1 expression were mixed with HCCLM3 and HepG2 hepatoma cells and then implanted in a nude mouse model to examine the effects of Robo1 in endothelial cells on tumor growth and angiogenesis. Cell motility-related molecules were studied to investigate the potential mechanism how Robo1 promoted tumor angiogenesis in HCC. The disease-free survival of the patients with high Robo1 expression in tumoral endothelial cells was significantly shorter than that of those with low expression (P = 0.021). Overexpression of Robo1 in HUVECs resulted in increased proliferation, motility, and tube formation in vitro. In the implanted mixture of tumor cells and HUVECs with an increased Robo1 expression, tumor growth and microvessel density were enhanced compared with controls. Robo1 promoted cell division cycle 42 (Cdc42) expression in HUVECs, and a distorted actin cytoskeleton in HUVECs was observed when Robo1 expression was suppressed. In conclusion, Robo1 promoted angiogenesis in HCC mediated by Cdc42.

Overexpression of Roundabout4 predicts poor prognosis of primary glioma patients via correlating with microvessel density

Roundabout4 (Robo4), a new member of Robo proteins family, is specifically expressed in endothelial cells. Recent studies have indicated that Robo4 could regulate tumor angiogenesis and vascular permeability. However, the role and function of Robo4 are not well understood. This study was performed to investigate the expression of Robo4 in primary glioma patients, and thus to determine the association of Robo4 expression with microvessel density and survival of glioma patients. In this study, real-time PCR and immunohistochemistry were performed to examine the mRNA level and protein expression of Robo4 in both 43 cases of glioma samples and 10 cases of normal brain tissue samples. The results demonstrated that Robo4 was significantly up-regulated in glioma tissues compared with normal brain tissues. In addition, double immunofluorescent staining revealed that Robo4 expression co-localized with CD34 expression in the vessel of glioma tissues. The expression of Robo4 positively correlated with patients' age (P = 0.0139) and glioma grade (P < 0.0001). A linear correlation was observed between the relative mRNA expression of Robo4 values and corresponding microvessel density values (r = 0.9735, P < 0.0001). Kaplan-Meier analysis and log-rank test result showed that the overall survival of patients with Robo4 high expression was significantly shorter than that of patients with Robo4 low expression (P < 0.001). The results of present study verify that overexpression of Robo4 is related to poor prognosis of primary gliomas patients through correlating with microvessel density.