Critical Evaluation of a microRNA-Based Risk Classifier Predicting Cancer-Specific Survival in Renal Cell Carcinoma with Tumor Thrombus of the Inferior Vena Cava

Metformin Regulates the miR-205/VEGFA Axis in Renal Cell Carcinoma Cells: Exploring a Clinical Synergism with Tyrosine Kinase Inhibitors

INTRODUCTION

Metformin (MF) intake could be associated with a favorable outcome in sunitinib (SUT)- and axitinib (AX)-treated clear cell renal cell carcinoma (ccRCC) patients. Functionally, MF induces miR-205, a microRNA serving as a tumor suppressor in several cancers.

METHODS

Real-time quantitative PCR, viability assays, and Western blotting analyzed MF and SUT/AX effects in RCC4 and 786-O cells. A tetracycline-inducible overexpression model was used to study the role of miR-205 and its known target gene, VEGFA. We analyzed miR-205 and VEGFA within a public and an in-house ccRCC cohort. Human umbilical vein endothelial cell (HUVEC) sprouting assays examined miR-205 effects on angiogenesis initiation. To determine the influence of the von Hippel-Lindau tumor suppressor (VHL), we examined VHLwt reexpressing RCC4 and 786-O cells.

RESULTS

Viability assays confirmed a sensitizing effect of MF toward SUT/AX in RCC4 and 786-O cells. Overexpression of miR-205 diminished VEGFA expression - as did treatment with MF. Tumor tissue displayed a downregulation of miR-205 and an upregulation of VEGFA. Accordingly, miR-205 caused less and shorter vessel sprouts in HUVEC assays. Finally, VHLwt-expressing RCC4 and 786-O cells displayed higher miR-205 and lower VEGFA levels.

CONCLUSION

Our results support the protective role of MF in ccRCC and offer functional insights into the clinical synergism with tyrosine kinase inhibitors.

The Role of Anticoagulation in Tumor Thrombus Associated with Renal Cell Carcinoma: A Literature Review

Tumor thrombus (TT) is a complication of renal cell carcinoma (RCC) for which favorable medical management remains undefined. While radical nephrectomy has been shown to increase overall survival in RCC patients, surgical interventions such as cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) utilized to perform TT resection carry high mortality rates. While it has been documented that RCC with TT is associated with venous thromboembolism (VTE) development, anticoagulation use in these patients remains controversial in clinical practice. Whether anticoagulation is associated with improved survival outcomes remains unclear. Furthermore, if anticoagulation is initiated, there is limited evidence for whether direct oral anticoagulants (DOACs), heparin, or warfarin serve as the most advantageous choice. While the combination of immunotherapy and tyrosine kinase inhibitors (TKIs) has been shown to improve the outcomes of RCC, the clinical benefits of this combination are not well studied prospectively in cases with TT. In this literature review, we explore the challenges of treating RCC-associated TT with special attention to anticoagulation. We provide a comprehensive overview of current surgical and medical approaches and summarize recent studies investigating anticoagulation in RCC patients undergoing surgery, targeted therapy, and/or immunotherapy. Our goal is to provide clinicians with updated clinical insight into anticoagulation for RCC-associated TT patients.

Integrative transcriptome and proteome analyses of clear cell renal cell carcinoma develop a prognostic classifier associated with thrombus

Clear cell renal cell carcinoma (ccRCC) with venous tumor thrombus (VTT) is associated with poor prognosis. Our integrative analyses of transcriptome and proteome reveal distinctive molecular features of ccRCC with VTT, and yield the development of a prognostic classifier to facilitate ccRCC molecular subtyping and treatment. The RNA sequencing and mass spectrometry were performed in normal-tumor-thrombus tissue triples of five ccRCC patients. Statistical analysis, GO and KEGG enrichment analysis, and protein-protein interaction network construction were used to interpret the transcriptomic and proteomic data. A six-gene-based classifier was developed to predict patients' survival using Cox regression, which was validated in an independent cohort. Transcriptomic analysis identified 1131 tumorigenesis-associated differentially expressed genes (DEGs) and 856 invasion-associated DEGs. Overexpression of transcription factor EGR2 in VTT indicated its important role in tumor invasion. Furthermore, proteomic analysis showed 597 tumorigenesis-associated differentially expressed proteins (DEPs) and 452 invasion-associated DEPs. The invasion-associated DEPs showed unique enrichment in DNA replication, lysine degradation, and PPAR signaling pathway. Integration of transcriptome and proteome reveals 142 tumorigenesis-associated proteins and 84 invasion-associated proteins displaying changes consistent with corresponding genes in transcriptomic profiling. Based on their different expression patterns among normal-tumor-thrombus triples, RAB25 and GGT5 were supposed to play a consistent role in both tumorigenesis and invasion processes, while SHMT2 and CADM4 might play the opposite roles in tumorigenesis and thrombus invasion. A prognostic classifier consisting of six DEGs (DEPTOR, DPEP1, NAT8, PLOD2, SLC7A5, SUSD2) performed satisfactorily in predicting survival of ccRCC patients (HR = 4.41, P < 0.001), which was further validated in an independent cohort of 40 cases (HR = 5.52, P = 0.026). Our study revealed the transcriptomic and proteomic profiles of ccRCC patients with VTT, and identified the distinctive molecular features associated with VTT. The six-gene-based prognostic classifier developed by integrative analyses may facilitate ccRCC molecular subtyping and treatment.