Topoisomerase I-IN-21 

Topoisomerase I-IN-21 is a promising topoisomerase I inhibitor with an IC₅₀ of 18.79 μM. Topoisomerase I-IN-21 shows higher selectivity toward cancer cells over normal CD8⁺ cells. Topoisomerase I-IN-21 induces G0/G1 cell cycle arrest and apoptosis. Topoisomerase I-IN-21 activates the cGAS-STING pathway, leading to enhanced immune gene expression. Topoisomerase I-IN-21 can be used for research on leukemia, non-small-cell lung, colon, central nervous system, melanoma, ovarian, renal, prostate, and breast cancers^[1].

Topoisomerase I-IN-21 (compound 5c) (0.01-100 μM) exhibits IC₅₀s ranged from 0.01 μM to 100 μM and mean graph midpoint values for growth inhibition of 0.04 in NCI-60 human cancer cell lines^[1].
Topoisomerase I-IN-21 (0.01-100 μM) exhibits IC₅₀s of 1.397 μM and 70.58 μM in SR leukemia cells and PCS-800-017 normal cell line, respectively^[1].
Topoisomerase I-IN-21 (1-100 μM; 45 min) exhibits Topo I inhibitory activity in a concentration-dependent manner^[1].
Topoisomerase I-IN-21 (18.79 μM; 24 h) induces cell cycle arrest and induces apoptosis in SR Leukemia cells^[1].
Topoisomerase I-IN-21 (10 μg/mL; 24 h) significantly elevates the concentration levels of STING, INF-β, TNF-α, Bax and CASP3 in SR leukemia cells^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

531.02

C₂₉H₂₃ClN₂O₄S

N#CC1=C(/N=C/C2=CC=C(Cl)C=C2)OC(C3=CC=CC(C)=C3S4)=C4C1C5=CC(OC)=C(OC)C(OC)=C5

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• [1]. Alhamaky SM, et al. Design, synthesis and docking studies of new benzothiophene and benzothienopyran derivatives as topoisomerase I inhibitors with potential immunomodulatory action via cGAS-STING signaling pathway. Bioorg Chem. 2026 Jun 15;174:109757.