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Protein / target

DNA topoisomerase 1

Encoded byTOP1P11387Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
10
Approved medicines
Open Targets target-level
View by indication →
30
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

Protein serine/threonine kinase

Strongest disease association

Small Cell Lung Carcinoma

Via encoding gene TOP1 · Clinical evidence · score 0.65

Therapeutic position

Established drug target

Small molecules

Derived from structured UniProt, Open Targets and literature data on this page.

Protein profile

UniProt 2026_02

Canonical identity and biological annotation from UniProt.

Function overview

Releases the supercoiling and torsional tension of DNA introduced during the DNA replication and transcription by transiently cleaving and rejoining one strand of the DNA duplex.

View complete UniProt function annotation

Releases the supercoiling and torsional tension of DNA introduced during the DNA replication and transcription by transiently cleaving and rejoining one strand of the DNA duplex. Introduces a single-strand break via transesterification at a target site in duplex DNA. The scissile phosphodiester is attacked by the catalytic tyrosine of the enzyme, resulting in the formation of a DNA-(3'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 5'-OH DNA strand. The free DNA strand then rotates around the intact phosphodiester bond on the opposing strand, thus removing DNA supercoils. Finally, in the religation step, the DNA 5'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone (By similarity). Regulates the alternative splicing of tissue factor (F3) pre-mRNA in endothelial cells. Involved in the circadian transcription of the core circadian clock component BMAL1 by altering the chromatin structure around the ROR response elements (ROREs) on the BMAL1 promoter

Subcellular location

Nucleus, nucleolusNucleus, nucleoplasm
Domains and Gene Ontology detail (39)

Domains & features

Topo IB-type catalytic

Gene Ontology

  • Cchromosome
  • Cdense fibrillar component
  • Cfibrillar center
  • Cnucleolus
  • Cnucleoplasm
  • Cnucleus
  • CP-body
  • Cperikaryon
  • Cprotein-DNA complex
  • FATP binding
  • Fchromatin binding
  • Fchromatin DNA binding

765 aa · 91 kDa

Biological roles

Reactome v97

What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.

Transcriptional regulationUniProt · GO
View supporting evidence

Transcriptional regulation

  • ·Releases the supercoiling and torsional tension of DNA introduced during the DNA replica…
  • ·RNA polymerase II cis-regulatory region sequence-specific DNA binding
  • ·circadian regulation of gene expression
  • ·rRNA transcription
View underlying pathways (1)

Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.

Interaction neighbourhood

STRING v12.0

Proteins with the strongest functional or physical association. Node size and line weight reflect STRING confidence; hover or select a partner to inspect one association.

TOP2ATDP1TOP2BTP53TOPORSPARP1ALYREFSRSF1BTBD1RBMXTOP1

10 strongest partners — larger node and heavier line mean higher confidence

Functional and physical associations from STRING v12.0. Only associations with this protein are drawn — partner-to-partner links are not part of this evidence.

Approved medicines with mapped indications

2 medicines · 3 areas

Approved therapies targeting this protein, grouped by what they are approved to treat — the disease-first view of the medicines below. Relationships come from the canonical approved-indication graph (ChEMBL phase-4), the same source as the drug cards.

Triple Negative Breast Neoplasms1 medicine
Broader indication categories (1)

Broad umbrella indications (e.g. “Neoplasms”). Shown here because every medicine also appears under a more specific disease above — kept for completeness, de-emphasised for clarity.

10 medicines meet Open Targets' target-level approved-medicine definition; the 2 shown here are those on this page with a canonical approved disease indication in the graph. Approved indications from ChEMBL (phase-4), via the canonical drug→disease graph.

Drugs targeting this protein

5

How approved and investigational drugs engage this protein — mechanism and action type, direct vs complex targeting, and how broadly each acts across other targets. A drug-first view (the section above groups the approved ones disease-first); direct binders with few recorded targets are listed first.

trastuzumab deruxtecan
Narrow target profileApprovedInhibitor

DNA topoisomerase I inhibitor

Indicated for Breast Neoplasms, Neoplasms

Direct interaction with this protein · 1 of 2 recorded protein targets — narrow recorded profile

sacituzumab govitecan
Narrow target profileApprovedInhibitor

DNA topoisomerase I inhibitor

Indicated for Breast Neoplasms, Triple Negative Breast Neoplasms, Neoplasms

Direct interaction with this protein · 1 of 2 recorded protein targets — narrow recorded profile

patritumab deruxtecan
Narrow target profileApprovedInhibitor

DNA topoisomerase I inhibitor

Direct interaction with this protein · 1 of 2 recorded protein targets — narrow recorded profile

datopotamab deruxtecan
Narrow target profileApprovedInhibitor

DNA topoisomerase I inhibitor

Direct interaction with this protein · 1 of 2 recorded protein targets — narrow recorded profile

Becatecarin
Narrow target profilePhase 3Inhibitor

DNA topoisomerase I inhibitor

Direct interaction with this protein · 1 of 3 recorded protein targets — narrow recorded profile

ChEMBL mechanism, action type, target identity and approved indications. Open Targets clinical status.

Translational evidence

Open Targets 26

Why this target matters therapeutically, strongest evidence first. Disease associations are gene-level (via the gene that encodes this protein) and open into the full confidence synthesis; the development universe, tractability and safety annotations are target-level, from Open Targets.

Strongest disease associations · via encoding gene TOP1

Gene-level evidence surfaced through the gene TOP1 that encodes this protein — not a direct protein–disease relationship. Ranked by Forefront's causal-directness weighting, so genetically- and clinically-evidenced diseases lead over ones that merely share the literature.

Small Cell Lung Carcinoma
0.81Well supported

Clinical evidence dominant · Open Targets 0.65

Neoplasms
0.76Well supported

Clinical evidence dominant · Open Targets 0.60

Carcinoma, Non-Small-Cell Lung
0.74Moderately supported

Clinical evidence dominant · Open Targets 0.58

Uterine Cervical Neoplasms
0.70Moderately supported

Clinical evidence dominant · Open Targets 0.57

Ovarian Neoplasms
0.70Moderately supported

Clinical evidence dominant · Open Targets 0.56

View evidence synthesis (5)
Small Cell Lung CarcinomaWell supported
0.81
agreement 0.690.93
Clinical70%Somatic mutation19%Literature11%

Open Targets aggregate 0.65 · 3 independent evidence families

NeoplasmsWell supported
0.76
agreement 0.640.88
Clinical77%Literature13%Somatic mutation11%

Open Targets aggregate 0.60 · 3 independent evidence families

Carcinoma, Non-Small-Cell LungModerately supported
0.74
agreement 0.620.86
Clinical70%Somatic mutation21%Literature8%

Open Targets aggregate 0.58 · 3 independent evidence families

Uterine Cervical NeoplasmsModerately supported
0.70
agreement 0.550.86
Clinical98%Literature2%

Open Targets aggregate 0.57 · 2 independent evidence families

Ovarian NeoplasmsModerately supported
0.70
agreement 0.550.86
Clinical91%Literature9%

Open Targets aggregate 0.56 · 2 independent evidence families

The evidence agreement range shows how closely the independent evidence families agree — it is not a statistical confidence interval, and nothing here is fitted to outcome data. Derived from Open Targets evidence types under Forefront weighting; the per-type scores above show the calculation.

Show all associations
Small Cell Lung Carcinoma0.65
Neoplasms0.60
Carcinoma, Non-Small-Cell Lung0.58
Uterine Cervical Neoplasms0.57
Ovarian Neoplasms0.56
Triple Negative Breast Neoplasms0.55
Neurodegenerative Diseases0.52
Carcinoma0.51

Drug development

26 compounds recorded · 10 approved · 16 in clinical development

Open Targets' development universe — every compound recorded against the target at any stage, not all approved medicines. Distinct from the 5 drugs that target this protein in Forefront's canonical graph (2 with a mapped approved indication, shown above): these count different sets and are not a subset relation.

View all recorded compounds (10)
DIFLOMOTECANPhase 2
TOPOTECANApproval
LABETUZUMAB GOVITECANPhase 2
CAMPTOTHECIN-20-O-PROPIONATEPhase 2
DATOPOTAMAB DERUXTECANApproval
AR-67Phase 2
MURELETECANPhase 1
BELOTECANApproval
IRINOTECAN HYDROCHLORIDEApproval
SACITUZUMAB GOVITECANApproval

Open Targets known-drugs universe. Drug name and highest clinical stage only — the disease relationship is NOT read from this slice (it carries trial-context noise); approved indications come from the canonical graph above.

Tractability

Small moleculesStrong

Approved Drug and Structure with Ligand support this modality.

Protein degradersEmerging

Feasibility evidence (uniprot ubiquitination and database ubiquitination) — no clinical-stage drug of this modality recorded.

Other modalitiesStrong

Approved Drug support this modality.

View underlying tractability evidence (10)
SM · Approved DrugSM · Structure with LigandSM · High-Quality LigandSM · High-Quality PocketSM · Druggable FamilyPR · UniProt UbiquitinationPR · Database UbiquitinationPR · Half-life DataPR · Small Molecule BinderOC · Approved Drug

Raw Open Targets tractability assessment buckets, by modality.

Safety-related annotations

NeutropeniaClinPGx

Terms indexed against this target in Open Targets' safety data, with their datasource. These are annotations, not causal claims: the direction of effect (whether activation or inhibition is implicated), species and evidence strength are not captured here, so an entry does not mean that modulating this target is known to cause that condition.

Clinical trials

30

Trials of drugs that target this protein — reached indirectly through those drugs, so a trial listed here studies the drug, not the protein. Ranked by active status, then clinical phase and recency, and spread across the targeting drugs.

View all trials (26)

ClinicalTrials.gov via the drug-target graph.

What's happening now

12

Recent therapeutic activity around this target — regulatory actions, clinical trials and safety signals for 4 drugs that target this protein, plus publications where such a drug is a genuine subject. Every item is reached indirectly through the drug, not the protein itself; incidental mentions (a paper that merely measures a drug) and press items are excluded.

  1. Trial status changed2026-07-21

    A Phase I/II Study of Sacituzumab Govitecan Plus Berzosertib in Small Cell Lung Cancer, Extra-Pulmonary Small Cell Neuroendocrine Cancer and Homologous Recombination-Deficient Cancers Resistant to PARP Inhibitors

    Status changed to Completed · ClinicalTrials.gov · via sacituzumab govitecan

  2. Indication expanded2026-06-24

    Indication expansion: SACITUZUMAB GOVITECAN (BLA761115)

    fda · regulatory · fda · via sacituzumab govitecan

  3. Indication expanded2026-06-24

    Indication expansion: SACITUZUMAB GOVITECAN (BLA761115)

    fda · regulatory · fda · via sacituzumab govitecan

  4. New publication2026-01-01
    Sacituzumab Govitecan plus Pembrolizumab for Advanced Triple-Negative Breast Cancer.

    The New England journal of medicine · 2026 · 3 citations · Europe PMC · via sacituzumab govitecan

  5. New publication2025-05-30
    Patritumab deruxtecan in leptomeningeal metastatic disease of solid tumors: the phase 2 TUXEDO-3 trial.

    Nature medicine · 2025 · 16 citations · Europe PMC · via patritumab deruxtecan

  6. Regulatory approval2025-04-04

    Approval: Datroway (EMA)

    ema · regulatory · ema · via datopotamab deruxtecan

  7. Label change2025-03-26

    Label change: SACITUZUMAB GOVITECAN (BLA761115)

    fda · regulatory · fda · via sacituzumab govitecan

  8. New publication2024-12-01
    Trastuzumab Deruxtecan with Nivolumab in HER2-Expressing Metastatic Breast or Urothelial Cancer: Analysis of the Phase Ib DS8201-A-U105 Study.

    Clinical cancer research : an official journal of the American Association for Cancer Research · 2024 · 31 citations · Europe PMC · via trastuzumab deruxtecan

  9. Indication expanded2024-11-22

    Indication expansion: SACITUZUMAB GOVITECAN (BLA761115)

    fda · regulatory · fda · via sacituzumab govitecan

  10. New publication2024-10-01
    Sacituzumab govitecan in HR<sup>+</sup>HER2<sup>-</sup> metastatic breast cancer: the randomized phase 3 EVER-132-002 trial.

    Nature medicine · 2024 · 32 citations · Europe PMC · via sacituzumab govitecan

  11. New publication2024-09-13
    Trastuzumab deruxtecan in HER2-positive advanced breast cancer with or without brain metastases: a phase 3b/4 trial.

    Nature medicine · 2024 · 142 citations · Europe PMC · via trastuzumab deruxtecan

  12. New publication2024-07-31
    Efficacy and Safety of Sacituzumab Govitecan in Patients With Advanced Solid Tumors (TROPiCS-03): Analysis in Patients With Advanced Endometrial Cancer.

    Journal of clinical oncology : official journal of the American Society of Clinical Oncology · 2024 · 37 citations · Europe PMC · via sacituzumab govitecan

Objective event titles are shown unmodified; the event kind and significance line are derived from structured fields. Forefront AttentionEvent stream aggregating Europe PMC Regulatory filings ClinicalTrials.gov.