The RNA helicases DDX19A/B modulate selinexor sensitivity by regulating MCL1 mRNA nuclear export in leukemia cells

Tatsuya Terasaki1, Yuichiro Semba1,2, Kensuke Sasaki1,3

  • 1Department of Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.

Leukemia
|July 10, 2024
PubMed

Insights

Selinexor sensitivity in leukemia is regulated by DDX19A/B RNA helicases controlling MCL1 export. Targeting these helicases alongside selinexor induces apoptosis, suggesting DDX19A/B as potential biomarkers.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • Selinexor, an exportin1 (XPO1) inhibitor, shows anti-tumor potential but faces clinical limitations due to toxicity and lack of predictive biomarkers.
  • Identifying molecular regulators of selinexor sensitivity is crucial for optimizing its therapeutic application in leukemia.

Purpose of the Study:

  • To uncover key molecules and pathways influencing selinexor sensitivity in B-acute lymphoblastic leukemia (B-ALL).
  • To investigate the role of DDX19A and DDX19B RNA helicases in selinexor response and MCL1 regulation.

Main Methods:

  • Genome-wide CRISPR/Cas9 dropout screens were employed in B-ALL cell lines.
  • MCL1 mRNA nuclear export and protein levels were assessed following DDX19A/B depletion.
  • Synergistic effects of selinexor and DDX19A/B depletion on leukemia cell apoptosis were evaluated.
  • Depmap datasets were analyzed to assess DDX19B expression in T-ALL lines.

Main Results:

  • DDX19A and DDX19B were identified as novel modulators of selinexor sensitivity by regulating MCL1 mRNA nuclear export.
  • Dual depletion of DDX19A/B significantly reduced MCL1 protein levels and enhanced selinexor-induced apoptosis.
  • MCL1 overexpression rescued the apoptotic effect, confirming its role in selinexor sensitivity.
  • T-ALL lines with low DDX19B expression showed sensitivity to selinexor or DDX19A depletion.

Conclusions:

  • Exportin1 (XPO1) and DDX19A/B RNA helicases coordinately regulate cellular MCL1 levels.
  • DDX19A/B paralogs show promise as biomarkers for predicting selinexor treatment response.
  • Targeting DDX19 paralogs presents a potential therapeutic strategy to induce apoptosis in leukemia.

Related Concept Videos

Nuclear Export of mRNA02:31

Nuclear Export of mRNA

Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
7.6K
MicroRNAs01:22

MicroRNAs

MicroRNA (miRNA) are short, regulatory RNA transcribed from introns—non-coding regions of a gene—or intergenic regions—stretches of DNA present between genes. Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After...
21.3K
Regulation of Expression Occurs at Multiple Steps02:24

Regulation of Expression Occurs at Multiple Steps

Gene expression can be regulated at almost every step from gene to protein. Transcription is the step that is most commonly regulated. This involves the binding of proteins to short regulatory sequences on the DNA. This association can either promote or inhibit the transcription of a gene associated with the respective sequence.
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
22.6K
Nuclear Export01:42

Nuclear Export

The nucleus restricts several proteins within and allows others to pass. The restricted proteins possess a nuclear retention sequence or NRS, anchoring them to the nuclear lamins and preventing their transport to the cytosol. The non-restricted proteins, after their synthesis, are transported to their site of action, such as the cytosol or other organelles, with the help of nuclear export signals or NES.
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
3.6K
Chromatin Structure Regulates pre-mRNA Processing02:41

Chromatin Structure Regulates pre-mRNA Processing

In eukaryotic cells, nascent mRNA transcripts need to undergo many post-transcriptional modifications to reach the cell cytoplasm and translate into functional proteins. For a long time, transcription and pre-mRNA processing were considered two independent events that occur sequentially in the cell. However, it has now been well established that transcription and pre-mRNA processing are two simultaneous processes that are precisely regulated inside the cell.
The chromatin structure, especially...
7.0K