CXCR4 antagonist 7 (Compound PARA-B) is a potent CXCR4 inhibitor (IC50 = 9.3 nM) [1] applicable in research on HIV infection, inflammatory diseases, cancer, and WHIM syndrome.

CXCR4 antagonist 7 (PARA-B, 10 nM to 1 μM, various durations) inhibits GH4C1 cell activities. At 10 nM to 1 μM for 20 hours, it suppresses CXCL12-stimulated GH4C1 proliferation with an IC50 of 9.3 nM. At 1 μM for 12 hours, it reduces CXCL12-dependent GH4C1 migration by 50%. At 50 nM for 30 minutes, it decreases CXCL12-induced ERK1/2 phosphorylation. It inhibits CXCL12-triggered GH4C1 proliferation and migration via CXCR4 inhibition. At 1 μM for 24 hours, no adverse effects on GH4C1 cell viability were observed. It also inhibits various cancer cell proliferations (10 nM-1 μM, 20-24 hours, IC50 values 1.08-3.45 μM) without affecting GH4C1 viability. In migration assays (50 nM-1 μM, 12 hours for GH4C1 and 30 minutes for GH4A11), it significantly reduces GH4C1 migration, with no effect on GH4A11 cells, even with CRISPR-Cas9-induced CXCR4 mRNA reduction. Western blot analysis confirms the reduction in CXCL12-induced ERK1/2 phosphorylation at 50 nM for 30 minutes.