CircME1 promotes aerobic glycolysis and sunitinib resistance of clear cell renal cell carcinoma through cis-regulation of ME1.

Circular RNAs (circRNAs) play critical roles in clear cell renal cell carcinoma (ccRCC). However, their involvement in sunitinib resistance remains largely unknown. Herein, we identified a novel circRNA, named circME1, which contributes to sunitinib resistance development in ccRCC. CircME1 also promoted proliferation, migration, and invasion of ccRCC cells. Further mechanism analysis showed that circME1 interacted with U1 snRNP at the promoter of its parental gene ME1, thereby upregulating the expression of ME1, enhancing aerobic glycolysis of ccRCC, and promoting its malignant phenotype. Furthermore, ME1 specific inhibitor could effectively repress the oncogenic functions of circME1. Taken together, our study demonstrates that the circME1/ME1 pathway is involved in ccRCC progression and sunitinib resistance development, which may be exploited for anticancer therapy.

Matrix metalloproteinase-9 is required for vasculogenic mimicry by clear cell renal carcinoma cells.

BACKGROUND: Vasculogenic mimicry (VM), a new pattern of tumor microcirculation system, has been proved to be important for tumor growth and progression and may be one of the causes of antiangiogenesis resistance. Matrix metalloproteinase-9 (MMP9) was shown to correlate with VM formation in some other cancers. However, the relationship between VM formation and MMP9 in renal cell carcinoma (RCC) has not been determined. METHODS: The VM formation and MMP9 expressions were analyzed by CD34/periodic acid-Schiff dual staining and immunohistochemistry in 119 RCC specimens. We used a well-established 3-dimention culture model to compare VM formation in 786-O, 769-P, and HK-2 cell lines in vitro. MMP9 expressions on either messenger RNA or protein levels were compared among the cell lines by quantitative polymerase chain reaction or Western blot. To determine further the relationship between MMP9 and VM in RCC, 786-O and 769-P were treated with specific MMP9 inhibitor or small interfering RNA. VM formation, cell migration, and invasion were subsequently assessed by 3-dimention culture, wound-healing, and transwell assays. RESULTS: Immunohistochemistry demonstrated both VM formation and MMP9 overexpression were positively associated with clinical staging, pathological grade, and metastasis (P<0.01). VM formation was closely correlated with MMP9 overexpression in RCC (r = 0.602, P<0.01). Lower MMP9 expression level was observed in normal kidney cell line HK-2, which was unable to form VM on Matrigel, whereas higher expression of MMP9 was found in VM-forming cancer cell lines 786-O and 769-P. Inhibition of MMP9 not only disrupted VM formation in 786-O and 769-P but also reduced cell migration and invasion. CONCLUSIONS: These results indicate an intimate relationship between MMP9 overexpression and VM formation in RCC. Treatments targeting VM formation by inhibiting the activity of MMP9 could be beneficial in RCC therapy.

Comparison between laparoscopic partial nephrectomy and laparoscopic ablation therapy: a meta-analysis.

OBJECTIVE: To conduct a meta-analysis of the literature evaluating comparisons on the peri-operative and oncological outcomes between laparoscopic partial nephrectomy (LPN) and laparoscopic ablation therapy (LAT) in the treatment of small renal masses (SRMs). MATERIAL AND METHODS: MEDLINE, EMBASE, Google Scholar, Cochrane Library, and CNKI were searched for clinical trials comparing LPN with LAT. Data of peri-operative and follow-up outcomes were extracted and compared. Publication bias was identified and sensitivity analysis was also performed. RESULTS: Data from 11 studies including 928 patients (525 patients in the LPN group and 403 in the LAT group) were collected. Baseline characteristics were compared and differences were found in age, preoperative renal function and proportion of solitary kidney (p < 0.05 respectively). For peri-operative outcomes, the LPN group had greater estimated blood loss, longer operative duration and length of hospital stay, and more peri-operative complications (p < 0.05, respectively). The LAT group had a significantly higher local recurrence (p < 0.05). There was no significant difference in postoperative change of renal function (p = 0.21). CONCLUSION: In comparison with LPN, LAT provides better peri-operative outcomes, but a higher local recurrence rate. LAT does not seem to provide an obvious advantage in protecting renal function. Further clinical trials with randomized design and long-term follow-up are needed.