MicroRNAs with prognostic potential for metastasis in clear cell renal cell carcinoma: a comparison of primary tumors and distant metastases

BACKGROUND

MicroRNAs (miRNAs) are regulators of gene expression in tumor development and progression. However, their influence on metastasis of clear cell renal cell carcinoma (ccRCC) is less understood. To determine the role of miRNAs in metastatic progression, miRNA expression in primary ccRCC was compared to distant metastases.

METHODS

Total RNA of 53 primary ccRCCs, 35 distant metastases from lung, bone, brain, and abdomen, as well as 17 normal kidney tissues was isolated from fresh frozen tissue and formalin-fixed paraffin-embedded (FFPE) samples. The miRNA microarrays were performed based on fresh frozen tissue. Results were validated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) on fresh frozen tissue and FFPE samples. Real-time cell analyses and transwell invasion assays were carried out after transient transfection of microRNA-30c (miR-30c) in cell line 786-O.

RESULTS

There were 14 miRNAs differently expressed in metastatic primary ccRCC and distant metastases compared to non-metastatic primary tumors. A strong correlation of miRNAs to progression-free- and cancer-specific 5-year-survival was determined. Specific miRNAs were differently expressed in distant metastases compared to primary ccRCC. A miRNA signature distinguished lung metastases from other metastatic sites. Overexpression of miR-30c increased adherence and decreased migration and invasion in the ccRCC cell line.

CONCLUSIONS

MiRNAs are deregulated in metastatic primary ccRCC and could be promising prognostic markers for an early prediction of metastasis. Alterations in miRNA expression characterize distant metastases of different metastatic sites. Furthermore, our study suggests a functional role of miR-30c in metastasis. The miRNAs could be a helpful tool for individual follow-up prediction and personalized therapy selection.

Pseudo aneurysm of the uterine artery with arteriovenous fistula after cesarean section: A rare but sinister cause of delayed postpartum hemorrhage

Pseudoaneurysm of the uterine artery is a rare complication of cesarean section. Delayed diagnosis and management may result in rapid and catastrophic postpartum hemorrhage and may necessitate hysterectomy or can even be fatal. A 28-year-old woman (gravida I, para I) presented with delayed postpartum hemorrhage 10 days after emergency cesarean section. Using transabdominal and transvaginal Color Doppler sonography, we detected a pseudoaneurysm in the posterior uterine wall, which was successfully treated with selective embolization distal and proximal to the lesion with platinum coils. In patients with delayed postpartum hemorrhage-especially after cesarean section-the rare possibility of uterine artery pseudoaneurysm must be kept in mind.

Abstract 1493: Specific miRNA signatures characterize different metastatic sites in clear cell renal cell carcinoma

Background: MiRNAs are regulators of gene expression in tumorigenesis and progression. To identify miRNAs associated with metastasis miRNA expression in distant metastases was compared to primary clear cell renal cell carcinoma (ccRCC).

Material and methods: Total RNA of 27 primary ccRCC samples and 25 distant metastases (lung, bone and brain) was isolated from formalin-fixed paraffin-embedded (FFPE) samples Microarray analyses were performed for a global miRNA expression profiling. Results were validated by qPCR. For miRNA target identification a ccRCC cell line (786-O) was transfected with miRNAs differently expressed in metastatic primary tumors and metastases.

Results: We identified 9 miRNAs (including miR-30c and miR-126) with a similar expression in metastatic primary ccRCC and distant metastases from different metastatic sites compared to non-metastatic primary ccRCC. 11 miRNAs (including miR-10b and miR-204) were differently expressed in distant metastases compared to primary ccRCC. Furthermore, each metastatic site is characterized by a specific miRNA signature. Results were verified on selected miRNAs using qPCR. In vitro studies identified potential miRNA targets and associated metastasis related pathways.

Discussion: These data suggest that miRNAs play an important role in metastatic processes of ccRCC. Furthermore, our results regarding different metastatic sites suggest two important statements. Specific miRNAs characterize distant metastases in general. On the other hand, miRNA expression is associated with specific conditions at different metastatic sites. Thus, the data presented in this study give the base for a better understanding of the involvement of miRNAs as regulators of metastasis which opens new possibilities for new targeted therapy options.

Citation Format: Joana Heinzelmann, Franzsika Stolzenbach, Robert Schneeweiss, Ulrike Wickmann, Sophie Baumgart, Mieczyslaw Gajda, Michael Stöckle, Kerstin Junker. Specific miRNA signatures characterize different metastatic sites in clear cell renal cell carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1493. doi:10.1158/1538-7445.AM2014-1493

Abstract 3168: Functional analysis and target identification of specific miRNAs involved in development of metastases in renal cell carcinoma

MicroRNAs (miRNAs) are short, non-coding RNA sequences which play an important role in cellular gene expression regulation on the post-transcriptional level. Recent studies have shown that they influence the regulation of tumor development in clear cell renal cell carcinoma (ccRCC), but their impact on metastasis is not investigated so far. We aimed in defining a specific miRNA expression pattern of metastasis in ccRCC. Furthermore, we focused on analysis of cellular functions and identification of target proteins of miRNAs involved in the metastatic process using cell lines. Total RNA from 44 ccRCC samples (including 22 non-metastatic and 22 metastatic tumors) and from 21 metastases was isolated using snap frozen tissue. Microarray analyses were performed for a global miRNA expression profiling. Results were validated by qRT-PCR. For functional analysis and target protein identification a metastatic (786-O) and a non-metastatic (KTCTL-30) ccRCC cell line was transfected with miRNAs differently expressed in metastatic tumors and metastases. Proliferation, migration and invasion assays were performed to investigate the influence of these miRNAs on the metastastic process. For identification of target proteins multiplex-fluorescent 2D gel electrophoresis of the transfected cell lines and database research were carried out. Microarray and qRT-PCR analyses showed that expression of specific miRNAs distinguishes between metastatic and non-metastatic ccRCC. Metastases have high similarity in miRNA expression to metastatic tumors. 9 miRNAs (including miR-451) are differentially expressed in primary metastatic tumors and metastases compared to non-metastatic tumors. Furthermore, a specific metastases miRNA pattern was detected. In addition, miR-30c expression level discriminates non-metastatic, metastatic tumors and metastases. Functional analysis on cell lines showed an significantly decreased migration after overexpression of miR-30c. It was possible to identify specific target candidates of miR-30c and miR-451 differently expressed in transfected cell lines by multiplex-fluorescent 2D gel electrophoresis. A specific miRNA expression pattern characterizes metastatic ccRCC. MiRNA expression in metastases is in accordance with primary metastatic tumors. Specific expression in metastases might be caused by a specific microenvironment at the metastatic site. MiR-30c regulates cellular processes involved in metastasis. MiRNA target identification can provide an insight into signal pathways deregulated in metastasis. Thus, several candidate target proteins of miR-30c and miR-451 were identified which have to be validated in this ongoing study using specific antibodies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3168. doi:1538-7445.AM2012-3168