Catalano Antonella, Haas Laura S, Zodel Kyra, Adlesic Mojca, Cuomo Francesca, Peighambari Asin, Metzger Patrick, Huang Hsin, Haug Stefan, Köttgen Anna, Köhler Natalie, Boerries Melanie, Frew Ian J
Clinic of Internal Medicine I, Hematology, Oncology and Stem Cell Transplantation, Medical Centre - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Institute of Medical Bioinformatics and Systems Medicine, Medical Centre-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Kidney Int. 2025 Apr;107(4):666-686. doi: 10.1016/j.kint.2024.12.003. Epub 2024 Dec 24.
RASSF1A is frequently biallelically inactivated in clear cell renal cell carcinoma (ccRCC) due to loss of chromosome 3p and promoter hypermethylation. Here we investigated the cellular and molecular consequences of single and combined deletion of the Rassf1a and Vhl tumor suppressor genes to model the common ccRCC genotype of combined loss of function of RASSF1A and VHL. In mouse embryonic fibroblasts and in primary kidney epithelial cells, double deletion of Rassf1a and Vhl caused chromosomal segregation defects and increased formation of micronuclei, demonstrating that pVHL and RASSF1A function to maintain genomic integrity. Combined Rassf1a and Vhl deletion in kidney epithelial cells in vivo increased proliferation and caused mild tubular disorganization, but did not lead to the development of kidney tumors. Single cell RNA-sequencing unexpectedly revealed that Rassf1a or Vhl deletion both induce the expression of an overlapping set of genes in a sub-population of proximal tubule cells. Many of these genes are also upregulated in the Vhl/Trp53/Rb1 deficient mouse model of ccRCC. In other subsets of proximal tubule cells, combined Vhl/Rassf1a deletion induced the expression of additional genes that were not upregulated in each of the single knockouts. The expression of the human homologues of Rassf1a-regulated genes correlate negatively with RASSF1 expression levels in human ccRCC. Our results suggest that the loss of RASSF1A function establishes a ccRCC-characteristic gene expression pattern.
由于3号染色体p臂缺失和启动子高甲基化，RASSF1A在透明细胞肾细胞癌（ccRCC）中经常发生双等位基因失活。在此，我们研究了Rassf1a和Vhl肿瘤抑制基因单缺失和联合缺失的细胞和分子后果，以模拟RASSF1A和VHL功能联合丧失的常见ccRCC基因型。在小鼠胚胎成纤维细胞和原代肾上皮细胞中，Rassf1a和Vhl的双缺失导致染色体分离缺陷并增加微核形成，表明pVHL和RASSF1A具有维持基因组完整性的功能。体内肾上皮细胞中Rassf1a和Vhl的联合缺失增加了细胞增殖并导致轻度肾小管紊乱，但未导致肾肿瘤的发生。单细胞RNA测序意外发现，Rassf1a或Vhl的缺失均在近端小管细胞亚群中诱导一组重叠基因的表达。在ccRCC的Vhl/Trp53/Rb1缺陷小鼠模型中，许多这些基因也上调。在近端小管细胞的其他亚群中，Vhl/Rassf1a联合缺失诱导了在每个单基因敲除中未上调的其他基因的表达。Rassf1a调控基因的人类同源物的表达与人类ccRCC中RASSF1的表达水平呈负相关。我们的结果表明，RASSF1A功能的丧失建立了一种ccRCC特征性的基因表达模式。
