Single-cell profiling reveals a dose gap between population-average and complete pY-STAT1/3 suppression by JAK inhibitors
Year: 2026
Type: preprint
Abstract: Strong suppression of a population-average signaling response need not place individual cells within the non-stimulated response range. We quantified this distinction in cytokine-induced JAK-STAT signaling using nuclear STAT1 phosphorylated at Tyr701 (pY-STAT1) and STAT3 phosphorylated at Tyr705 (pY-STAT3) in THP-1 and U937 cells exposed to six JAK-pathway inhibitors: solcitinib, BMS-911543, cerdulatinib, baricitinib, ruxolitinib, and tofacitinib. We compared arithmetic-mean inhibition and inhibition of the mean of log10-transformed single-cell responses (log-mean) with the fractions of cells leaving the stimulated response range or entering the non-stimulated range. Arithmetic-mean inhibition was left-shifted relative to log-mean inhibition, which more closely tracked departure from the stimulated range. Neither population summary uniquely specified entry into the non-stimulated range. At the lowest tested doses where fitted arithmetic-mean or log-mean inhibition reached 80%, median fractions remaining above that range were 76% and 37%, respectively. The apparent IC50 for complete-inhibition occupancy was a median 2.4-fold higher than the log-mean IC50 and 7.4-fold higher than the arithmetic-mean IC50. The size of this dose gap varied with cell line, inhibitor, and phospho-target within the tested panel. These results provide an empirical basis for interpreting conventional inhibition curves in terms of single-cell response fractions and show why population attenuation and complete-inhibition occupancy should be reported as distinct pharmacological endpoints.
Language: English
Subfield: Oncology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7224110266