1. Signaling Pathways
  2. Cell Cycle/DNA Damage
  3. Topoisomerase


Topoisomerases are enzymes that regulate the overwinding or underwinding of DNA. The winding problem of DNA arises due to the intertwined nature of its double-helical structure. Topoisomerases are isomerase enzymes that act on the topology of DNA. Type I topoisomerase cuts one strand of a DNA double helix, relaxation occurs, and then the cut strand is reannealed. Type I topoisomerases are subdivided into two subclasses: type IA topoisomerases, which share many structural and mechanistic features with the type II topoisomerases, and type IB topoisomerases, which utilize a controlled rotary mechanism. Type II topoisomerase cuts both strands of one DNA double helix, pass another unbroken DNA helix through it, and then reanneal the cut strands. This class is also split into two subclasses: type IIA and type IIB topoisomerases, which possess similar structure and mechanisms.

Topoisomerase Isoform Specific Products:

Cat. No. Product Name Effect Purity
  • HY-15142
    Doxorubicin hydrochloride
    Inhibitor 99.60%
    Doxorubicin (Hydroxydaunorubicin) hydrochloride, a cytotoxic anthracycline antibiotic, is an anti-cancer chemotherapy agent. Doxorubicin hydrochloride is a potent human DNA topoisomerase I and topoisomerase II inhibitor with IC50s of 0.8 μM and 2.67 μM, respectively. Doxorubicin hydrochloride reduces basal phosphorylation of AMPK and its downstream target acetyl-CoA carboxylase. Doxorubicin hydrochloride induces apoptosis and autophagy.
  • HY-13629
    Inhibitor 99.94%
    Etoposide (VP-16; VP-16-213) is an anti-cancer chemotherapy agent. Etoposide inhibits topoisomerase II, thus stopping DNA replication. Etoposide induces cell cycle arrest, apoptosis and autophagy.
  • HY-13631A
    Exatecan mesylate
    Inhibitor 99.91%
    Exatecan mesylate (DX8951f) is a DNA topoisomerase I inhibitor, with an IC50 of 2.2 μM (0.975 μg/mL). Exatecan mesylate can be used in cancer research.
  • HY-13631D
    Inhibitor ≥99.0%
    Dxd (Exatecan derivative for ADC) is a potent DNA topoisomerase I inhibitor, with an IC50 of 0.31 μM, used as a conjugated drug of HER2-targeting ADC (DS-8201a).
  • HY-13704
    Inhibitor 99.90%
    SN-38 (NK012) is an active metabolite of the Topoisomerase I inhibitor Irinotecan. SN-38 (NK012) inhibits DNA and RNA synthesis with IC50s of 0.077 and 1.3 μM, respectively.
  • HY-N2306A
    Aclacinomycin A hydrochloride
    Aclacinomycin A (Aclarubicin) hydrochloride is an orally active and potent anthracycline antitumor antibiotic. Aclacinomycin A hydrochloride is an inhibitor of topoisomerase I and II. Aclacinomycin A hydrochloride inhibits synthesis of nucleic acid, especially RNA. Aclacinomycin A hydrochloride might inhibit the 26S protease complex as well as the ubiquitin-ATP-dependent proteolysis.
  • HY-13631I
    (1S,9R)-Exatecan mesylate
    (1S,9R)-Exatecan mesylate ((1S,9R)-DX8951f) is an isomer of Exatecan mesylate (HY-13631A). Exatecan mesylate (DX8951f) is an inhibitor of DNA topoisomerase I with an IC50 of 2.2 μM (0.975 μg/mL) and can be used in cancer research.
  • HY-148819A
    NH2-bicyclo[1.1.1]pentane-7-MAD-MDCPT hydrochloride
    NH2-bicyclo[1.1.1]pentane-7-MAD-MDCPT (compound I) hydrochloride is a topoisomerase I inhibitor, which can be delivered to cells through conjugated antibody targeting, and has good ADC activity in vivo and in vitro.
  • HY-16562
    Inhibitor 99.84%
    Irinotecan ((+)-Irinotecan) is a topoisomerase I inhibitor, preventing religation of the DNA strand by binding to topoisomerase I-DNA complex.
  • HY-16560
    Inhibitor 99.82%
    Camptothecin (CPT), a kind of alkaloid, is a DNA topoisomerase I (Topo I) inhibitor with an IC50 of 679 nM. Camptothecin (CPT) exhibits powerful antineoplastic activity against colorectal, breast, lung and ovarian cancers, modulates hypoxia-inducible factor-1α (HIF-1α) activity by changing microRNAs (miRNA) expression patterns in human cancer cells.
  • HY-13768A
    Topotecan hydrochloride
    Inhibitor 99.76%
    Topotecan Hydrochloride (SKF 104864A Hydrochloride) is a Topoisomerase I inhibitor with potent antineoplastic activities.
  • HY-13062
    Daunorubicin hydrochloride
    Inhibitor 99.62%
    Daunorubicin (Daunomycin) hydrochloride is a topoisomerase II inhibitor with potent anti-tumor activity. Daunorubicin hydrochloride inhibits DNA and RNA synthesis. Daunorubicin hydrochloride is a cytotoxin that inhibits cancer cell viability and induces apoptosis and necrosis. Daunorubicin hydrochloride is also an anthracycline antibiotic. Daunorubicin hydrochloride can be used in the research of infection and variety of cancers, including leukemia, non-Hodgkin lymphomas, Ewing's sarcoma, Wilms' tumor.
  • HY-16562A
    Irinotecan hydrochloride
    Inhibitor 99.75%
    Irinotecan hydrochloride ((+)-Irinotecan hydrochloride) is a topoisomerase I inhibitor mainly used to treat colon cancer and rectal cancer.
  • HY-13502
    Inhibitor 98.36%
    Mitoxantrone is a potent topoisomerase II inhibitor. Mitoxantrone also inhibits protein kinase C (PKC) activity with an IC50 of 8.5 μM. Mitoxantrone induces apoptosis of B-CLL (B-chronic lymphocytic leukaemia) cells. Mitoxantrone shows antitumor activity. Mitoxantrone also has anti-orthopoxvirus activity with EC50s of 0.25 μM and and 0.8 μM for cowpox and monkeypox, respectively.
  • HY-18258
    Berberine chloride
    Inhibitor 99.66%
    Berberine chloride is an alkaloid that acts as an antibiotic. Berberine chloride induces reactive oxygen species (ROS) generation and inhibits DNA topoisomerase. Antineoplastic properties.
  • HY-13624A
    Epirubicin hydrochloride
    Inhibitor 99.16%
    Epirubicin hydrochloride (4'-Epidoxorubicin hydrochloride), a semisynthetic L-arabino derivative of doxorubicin, has an antineoplastic agent by inhibiting Topoisomerase. Epirubicin hydrochloride inhibits DNA and RNA synthesis. Epirubicin hydrochloride is a Forkhead box protein p3 (Foxp3) inhibitor and inhibits regulatory T cell activity.
  • HY-B0356
    Inhibitor 99.86%
    Ciprofloxacin (Bay-09867) is a potent, orally active topoisomerase IV inhibitor. Ciprofloxacin induces mitochondrial DNA and nuclear DNA damage and lead to mitochondrial dysfunction, ROS production. Ciprofloxacin has anti-proliferative activity and induces apoptosis. Ciprofloxacin is a fluoroquinolone antibiotic, exhibiting potent antibacterial activity.
  • HY-B0330
    Inhibitor 99.93%
    Levofloxacin ((-)-Ofloxacin) is an orally active antibiotic and is active against both Gram-positive and Gram-negative bacteria. Levofloxacin inhibits the DNA gyrase and topoisomerase IV. Levofloxacin can be used for chronic periodontitis, airway inflammation and BK Viremia research. Levofloxacin shows anti-orthopoxvirus activity.
  • HY-125033
    Inhibitor 99.96%
    EIDD-1931 (Beta-d-N4-hydroxycytidine; NHC) is a novel nucleoside analog and behaves as a potent anti-virus agent. EIDD-1931 effectively inhibits the replication activity of venezuelan equine encephalitis virus (VEEV), Chikungunya virus (CHIKV) and hepatitis C virus (HCV).
  • HY-10529
    Betulinic acid
    Inhibitor ≥98.0%
    Betulinic acid is a natural pentacyclic triterpenoid, acts as a eukaryotic topoisomerase I inhibitor, with an IC50 of 5 μM, and possesses anti-HIV, anti-malarial, anti-inflammatory and anti-tumor properties.

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