Acute hyperosmotic stress in HL-60/S4 leukemia cells is associated with decreased transcript levels of immediate-early genes, including FOS, JUN, and MYC, compared to baseline conditions and to responses in other cell types such as cardiomyocytes.

When cells are suddenly exposed to high salt or sugar, their nucleus shrinks and the DNA becomes tightly packed. This causes the cell to turn off proteins that normally silence genes, which should make more genes active. But instead, the cell stops making key stress-response genes like FOS, JUN, and MYC, while it ramps up production of building materials like ribosomes and mitochondria. This shift happens because the cell's gene-control system gets rewired to prioritize survival functions over rapid signaling, and the immediate-early genes are silenced as part of this new program.