bioRxiv Science⌕ Search

Biology subjects

Rahkola, J.

Publications and source records attributed to Rahkola, J..

2 recordsLinked to original sources

siRNA Mediated Genetic Perturbation of Primary Human Leukemia Stem and Progenitor Cells

Acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) are aggressive hematologic malignancies with poor outcomes. Leukemia stem and progenitor cells (LSPCs) are a subset of cells within the bulk tumor thought to be responsible for initiating disease and causing relapse. LSPCs evade chemotherapy partially due to their quiescent state. Therefore, studying this cell subpopulation is critical to identify new disease targets that can better the outcomes of AML/MDS patients. The use of RNAi and genetic approaches is technically challenging in primary leukemia cells and particularly LSPCs. Overcoming this technical hurdle could greatly expand the breath of pre-clinical and mechanistic examination of LSPCs. In this study, we describe a methodology to efficiently introduce siRNA, resulting in effective gene knock down in LSPCs. After isolation of LSPCs from primary patient samples, we showed that electroporation of these cells does not affect cell viability significantly. Further, using siGLO green transfection indicator, we show that RNA is introduced into the nucleus of these cells. siRNA transfection leads to efficient knockdown of target genes and has subsequent biological relevant activity. We have identified a method to effectively knock down genes in leukemia stem and progenitor cells, opening up new avenues to examine LSPC biology in human specimens.

cancer biology↗

STAT3 modulates mitochondrial function and plays a critical role in the survival of leukemic stem cells

Signal transducer and activator of transcription 3 (STAT3) is a well-described transcription factor that mediates oxidative phosphorylation and glutamine uptake in bulk acute myeloid leukemia (AML) cells and leukemic stem cells (LSCs). STAT3 has also been shown to translocate to the mitochondria in AML cells, particularly when phosphorylated at the serine 727 (pSTAT3 S727) residue. Inhibition of STAT3 results in impaired mitochondrial function and decreased leukemia cell viability. We discovered a novel interaction of STAT3 with voltage-dependent anion channel 1 (VDAC1) in the mitochondria that provides a mechanism through which STAT3 modulates mitochondrial function and cell survival. Through VDAC1, STAT3 regulates calcium and oxidative phosphorylation in the mitochondria. STAT3 and VDAC1 inhibition also results in significantly reduced engraftment potential of LSCs, including primary samples resistant to venetoclax. These results implicate STAT3 as a therapeutic target in AML.

cancer biology↗