Ivermectin increases expression of STAT1 and its target genes through a ROS-dependent mechanism. (A) OCI-AML2 cells were treated with 3μM ivermectin (IVM) for 30 hours. After treatment, RNA was isolated, reverse transcribed, and subjected to quantitative PCR using specific primers for STAT1A, STAT1B, and STAT1 target genes OAS1, TRIM22, and IFIT3. Data represent mean ± SD fold increase in gene expression normalized to 18S expression and compared with control cells. (B) OCI AML2, U937, and HL60 leukemia and DU145 and PPC-1 prostate cancer cells were treated with 6μM ivermectin for 24 hours, and mRNA levels of STAT1A and STAT1B were measured using qPCR and normalized to 18S expression as (A). Data represent mean ± SD fold increase in gene expression, compared with control cells. (C) OCI-AML2 cells (2.5 × 10⁵) were injected subcutaneously into the flanks of sublethally irradiated NOD/SCID mice. Once tumors were established, mice were treated with ivermectin (7 mg/kg) intraperitoneally or vehicle control for 5 days (n = 3 per group). After treatment, mice were killed, and tumors were harvested. mRNA was extracted, and changes in STAT1A and 1B expression were measured by qRT-PCR. Data represent mean ± SD fold increase in gene expression normalized to 18S expression, compared with tumors from control treated mice. (D) OCI-AML2 cells were treated simultaneously with ivermectin (3μM), the ROS scavenger, NAC (5μM), or both for 30 hours, and STAT1A and STAT1B expression was assessed as described for panel A. Relative expression values normalized to 18s are reported as fold-change ± SD compared with the untreated control for each gene.