hZIP1 that is down-regulated in clear cell renal cell carcinoma is negatively associated with the malignant potential of the tumor.

The human ZRT, IRT-like protein 1 (hZIP1) has been associated with tumorigenesis. However, its role in clear cell renal cell carcinoma (ccRCC) has not been yet reported. The objective was to investigate hZIP1 expression in ccRCC and its association with clinicopathological features. A total of 106 ccRCC tissue samples and corresponding normal kidney tissue samples were examined, along with 3 ccRCC cell lines (ACHN, 769-P, and 786-O). Real-time polymerase chain reaction, Western blot, and immunohistochemistry were used to investigate the expression of hZIP1 and its relationship with clinicopathological features. The ACHN cell line, exhibiting the highest hZIP1 expression, was transfected with hZIP1 small interfering RNA or mock small interfering RNA. Cellular proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Invasion was determined by Transwell assay. The level of hZIP1 was decreased in ccRCC tissues when compared with normal tissues. hZIP1 expression significantly decreased with increasing clinical stage and pathological grade in ccRCC samples (P<0.05), showing a significant negative correlation with the histological grade (P<0.05). High hZIP1 expression was associated with a better disease-free survival (P<0.01). Silencing of hZIP1 expression enhanced the proliferative and invasive abilities of ACHN cells. Results suggest that hZIP1 may act as a tumor suppressor in ccRCC. hZIP1 is closely correlated with clinicopathological features. High hZIP1 expression may be an indicator of good prognosis in ccRCC.

Dong X ，Kong C ，Zhang Z ，Liu X ，Zhan B ，Chen Z ，Shi D ... -  《-》

Dicer is down-regulated in clear cell renal cell carcinoma and in vitro Dicer knockdown enhances malignant phenotype transformation.

Although emerging evidence has shown that the deregulation of micro-ribonucleic acid (RNA) biogenesis machinery is involved in various human malignancies, this role has not been investigated in clear cell renal cell carcinoma (ccRCC). This study aims to determine whether Dicer, a key enzyme responsible for biogenesis of microRNA, is deregulated in ccRCC. The biological roles of Dicer in vitro are also determined. The expression of Dicer at messenger RNA and protein levels was detected by real-time quantitative polymerase chain reaction and western blot, respectively, in human kidney tubule epithelial cell line, nonmetastatic 786-O ccRCC cell line, and metastatic ACHN ccRCC cell line, as well as in 42 cases of ccRCC surgical specimens including 14 cases with distant metastasis and their corresponding adjacent normal renal tissues. Dicer expression levels in specimens were also measured by immunohistochemical staining. Knockdown of Dicer expression in 786-O and ACHN ccRCC cell lines was achieved by transfecting short interfering RNA against Dicer. The effects of Dicer on cell proliferation, migration, and invasion were detected by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay, flow cytometric analyses, and Boyden chamber Transwell assay, respectively. Compared with human kidney tubule epithelial cell line, Dicer expression levels were significantly down-regulated in 786-O and ACHN ccRCC cell lines, with the metastatic ACHN ccRCC cell line having even lower levels. Meanwhile, Dicer expression levels were significantly down-regulated in ccRCC surgical specimens compared with adjacent normal renal tissues, with the metastatic ones further reduced, and Dicer messenger RNA levels were significantly correlated with overall tumor-node-metastasis stage of ccRCC. In vitro, the knockdown of Dicer significantly promoted cell proliferation, migration, and invasion. Reduced expression of Dicer may play a role in the tumorigenesis of ccRCC and further decline may be associated with distant metastasis of ccRCC.

Ma X ，Fan Y ，Gao Y ，Zhang Y ，Huang Q ，Ai Q ，Ni D ，Chen W ，Zhang P ，Song E ，Wang B ，Shi T ，Zheng T ，Zhang X ... -  《-》

Reduced expression of growth and differentiation factor-9 (GDF9) is associated with aggressive behaviour of human clear-cell renal cell carcinoma and poor patient survival.

Growth and differentiation factor-9 (GDF9) is a member of the bone morphogentic protein (BMP) family. GDF9 was recently shown to be a regulator of the development and spread of cancer cells, including kidney cancer cells. However, the clinical implication of GDF9 in human clear-cell renal cell carcinoma (CCRCC) remains unknown. In the present study, the expression of GDF9 in human CCRCC tissues, and correlation between GDF9 and pathological grade and stage of the tumours were examined in CRCC specimens. The expression of GDF9 was examined in paired human normal renal and CCRCC tumour tissues (n=86). The expression of GDF9 in human renal tissues was assessed at both the mRNA and protein levels using reverse transcription-polymerase chain reaction and western blot. Furthermore, the survival curve was constructed using Kaplan-Meier method. Decreased GDF9 protein levels were seen in CCRCC tissues compared with normal tissues. Low protein levels were seen in tumours with high clinical stages and with high pathological nuclear grade of CCRCC. Likewise, levels of GDF9 transcript in normal renal specimens was significantly higher than that in CCRCC tissues. The transcript levels of GDF9 differed significantly amongst different clinical stages and different pathological nuclear grade of CCRCC: The higher the clinical stage or pathological nuclear grade of CCRCC, the lower the transcript level of GDF9. Cumulative survival curves indicated that GDF9 mRNA expression was negatively correlated with cumulative survival time. Patients with high level of GDF9 had significantly longer survival time than the patients with low level of GDF9 (p<0.001). GDF9 expression is markedly decreased in CCRCC, and is linked to pathological grade, clinical stage and long-term survival of the patients. This suggests that GDF9 is a potential tumour suppressor in CCRCC.

Du P ，Ye L ，Yang Y ，Jiang WG ... -  《-》

Down-regulation of CD74 inhibits growth and invasion in clear cell renal cell carcinoma through HIF-1α pathway.

To investigate the expression and function of CD74 in normal renal tissue and clear cell-renal cell carcinoma (ccRCC), as well as related renal tubule epithelial lines. We also analyzed the association between clinicopathological characteristics of ccRCCs and the expression levels of CD74. Immunostaining of CD74 was performed in 107 patients' renal tissue and cell lines. We evaluated the association between clinicopathological characteristics of ccRCC and CD74 levels using image analysis. CD74 expression levels were also analyzed by Western blot. Lentivirus-mediated CD74 knockdown inhibited the growth and invasion, of ccRCC cell lines 786-O in vitro and in vivo. Cell proliferation, apoptosis, and invasion as well as HIF-1α pathway-related proteins, were estimated by Western blot. All experiments were repeated at least 3 times. Immunostaining and image analysis showed strong immunoreactions of CD74 in all patients' ccRCC tissue and malignant cell lines, while CD74 expression levels were associated with tumor grade (P = 0.013). Western blot indicated that ccRCC tissue and malignant cell lines expressed higher levels of CD74 and hypoxia inducible factor 1α (HIF-1α) than adjacent normal renal tissue and normal cell HK-2. Vitro and vivo tests demonstrated that lentivirus-mediated CD74 knockdown inhibited the proliferation of ccRCC cell lines, induced G1/S arrest and apoptosis, and inhibited invasion. Inhibition of CD74 resulted in down-regulation of HIF-1α pathway proteins. CD74 was overexpressed in human ccRCCs and associated with tumor grade, and inhibition of CD74 produced ccRCC proliferation arrest, induced apoptosis, and inhibited invasion, which impinged on HIF-1α pathway-related proteins. It might represent a potential therapeutic target for ccRCC.

Ji SQ ，Su XL ，Cheng WL ，Zhang HJ ，Zhao YQ ，Han ZX ... -  《-》

High expression of long non-coding RNA SPRY4-IT1 predicts poor prognosis of clear cell renal cell carcinoma.

Zhang HM ，Yang FQ ，Yan Y ，Che JP ，Zheng JH ... -  《International Journal of Clinical and Experimental Pathology》