BACKGROUND: We have identified in cells co-expressing SIX2 and CITED1 the cancer stem cells (CSC) that regulate Wilms tumor (WT) development. Our comparative in vitro and in vivo analysis highlighted that mitochondrial dysregulation plays a critical role in modulating biology of these CSC. In this work, we have performed transcriptomics analysis and mechanistic in vitro studies to assess impact of mitochondria function on WT stem cell biology.
METHODS: SIX2+CITED1+ expressing CSC were isolated using smartflare probes from favorable and unfavorable WT and human fetal kidney (hFK) samples and processed for bulk and scRNA-seq. Differential gene expression and GO ontology analysis were performed to identify differences across samples. Data generated were further confirmed by bulk RNAseq on WT-CSC in which SIX2 or CITED1 were either knocked down or overexpressed, by Spatial Transcriptomics analysis, as well as by in vitro experiments and in vivo WT xenografts.
RESULTS: The scRNA-seq data uncovered significant variations in genes related to mitochondrial operations, specifically those governing mitochondrial division (such as DRAP1, DNM2, MFF, and MEIF2) and merging (like MFN1/2 and OPA1). These changes were linked to shifts in normal metabolic and oxidative states. Experiments that reduced the expression of SIX2 or CITED1 in WT cells confirmed their essential role in managing mitochondrial dynamics, which in turn affects cell growth and self-renewal. Spatial transcriptomics corroborated these observations, highlighting mitochondrial and metabolic imbalances in WT-CSCs.
CONCLUSIONS: For the first time, our data suggest that alterations in mitochondrial function may drive proliferation and progression of Wilms tumor. These insights also point to new potential targets for developing treatments for this cancer.
