Decoding the multicellular ecosystem of vena caval tumor thrombus in clear cell renal cell carcinoma by single-cell RNA sequencing

Abstract

Background Vascular invasion with tumor thrombus frequently occurs in advanced renal cell carcinoma (RCC). Thrombectomy is one of the most challenging surgeries with high rate of perioperative morbidity and mortality. However, the mechanisms driving tumor thrombus formation are poorly understood which is required for designing effective therapy for eliminating tumor thrombus. Results We perform single-cell RNA sequencing analysis of 19 surgical tissue specimens from 8 clear cell renal cell carcinoma (ccRCC) patients with tumor thrombus. We observe tumor thrombus has increased tissue resident CD8+ T cells with a progenitor exhausted phenotype compared with the matched primary tumors. Remarkably, macrophages, malignant cells, endothelial cells and myofibroblasts from TTs exhibit enhanced remodeling of the extracellular matrix. The macrophages and malignant cells from primary tumors represent proinflammatory states, but also increase the expression of immunosuppressive markers compared to tumor thrombus. Finally, differential gene expression and interaction analyses reveal that tumor-stroma interplay reshapes the extracellular matrix in tumor thrombus associated with poor survival. Conclusions Our comprehensive picture of the ecosystem of ccRCC with tumor thrombus provides deeper insights into the mechanisms of tumor thrombus formation, which may aid in the design of effective neoadjuvant therapy to promote downstaging of tumor thrombus and decrease the perioperative morbidity and mortality of thrombectomy.

Cellular milieu in clear cell renal cell carcinoma

“…Here, a single-cell transcriptomics study in locally invasive ccRCC identified CAFmediated extracellular matrix remodeling by the increased gene signature for the EMT pathway (29). Therefore, in both recurrent and locally invasive ccRCC, CAF infiltrate should be considered as an additional key cell type driving tumor progression and immunosuppression (29,73). Stromal cells in recurrent and locally invasive ccRCC.…”

“…Interestingly, CAF mediated EMT has been proposed within locally invasive ccRCC that rapidly extends into surrounding large vessels (Figure 3). Here, a single-cell transcriptomics study in locally invasive ccRCC identified CAFmediated extracellular matrix remodeling by the increased gene signature for the EMT pathway (29). Therefore, in both recurrent and locally invasive ccRCC, CAF infiltrate should be considered as an additional key cell type driving tumor progression and immunosuppression (29,73).…”

“…The above-mentioned single-cell transcriptomics profiles are from primary ccRCC lesions. However, a recent single-cell transcriptomics study of ccRCC primary, locally invasive, and adjacent normal tissue identified enhanced extracellular matrix (ECM) remodeling by malignant PTEC in locally invasive lesions (29). This indicates that while locally invasive ccRCC lesions may result from opportunistic extension into vasculature due to proximity, the extending malignant PTEC also require supporting ECM (29,30).…”

“…However, a recent single-cell transcriptomics study of ccRCC primary, locally invasive, and adjacent normal tissue identified enhanced extracellular matrix (ECM) remodeling by malignant PTEC in locally invasive lesions (29). This indicates that while locally invasive ccRCC lesions may result from opportunistic extension into vasculature due to proximity, the extending malignant PTEC also require supporting ECM (29,30). This ECM remodeling can be profiled by the collagen gene markers COL20A1, COL28A1, TGFB1, COL6A2, COL1A2, and COL4A2.…”

Improving the prognostic accuracy in renal cell carcinoma with venous thrombus with novel predictive nomograms

“…It results in possibly misleading and truly heterogeneous findings on 5-year overall survival (OS) of patients with RCC and coexisting tumor thrombus that is reported to be from 34% to 71% (2)(3)(4)(5). Recently, some novel promising factors have emerged besides classic clinicopathological features, but also blood countderived biomarkers, and immunohistochemical and genetic signatures (6)(7)(8).…”