TopoGEN

06/26/2026

🧬 Can DNA repair actually cause chemotherapy side effects?

A fascinating new NIH study suggests the answer may be yes.

Researchers discovered that neurons damaged by cisplatin begin repairing their DNA normally—but because these cells contain very low nucleotide (dNTP) pools, the repair process often stalls before completion.

Instead of protecting the cell, incomplete repair generates additional DNA damage that contributes to chemotherapy-induced peripheral neuropathy.

Even more exciting?

By restoring nucleotide pools, the researchers dramatically improved neuronal survival and reduced neuropathy in animal models.

This finding raises an important question:

Could similar strategies protect other normal tissues—including those affected by topoisomerase-targeting cancer drugs?

At TopoGEN, we believe these types of mechanistic studies represent the future of precision oncology. Our DNA damage and topoisomerase assay platforms help researchers investigate exactly these kinds of questions as new therapeutics move through development.



https://www.cell.com/cell/fulltext/S0092-8674(26)00584-2?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867426005842%3Fshowall%3Dtrue

06/12/2026

OK, this paper actually has massive implications for topoisomerase drug discovery because it challenges a long-standing assumption about TOP2 poisons. Rather than simply trapping the cleavage complex (as etoposide does), the authors propose that their modified epipodophyllotoxin derivative actively dismantles the TOP2β catalytic apparatus, producing an irreversible, religation-defective complex that leads to persistent DNA double-strand breaks.

06/05/2026

This paper explicitly demonstrates that HSF1 preferentially stimulates TOP2β catalytic engagement while having little effect on TOP2α, and further shows that pharmacologic HSF1 inhibition suppresses TOP2 poison toxicity in post-mitotic cells without reducing anti-cancer activity in proliferating cells. This has particularly important implications for anthracycline-associated cardiotoxicity because cardiomyocytes predominantly express TOP2β rather than TOP2α.

Konada et al. report that heat shock factor 1 (HSF1) selectively stimulates the topoisomerase II (TOP2) isoform, TOP2B, over TOP2A, in both dividing cells and postmitotic neurons. Employing HSF1 inhibitors could blunt the secondary toxicity of TOP2 poison-based chemotherapy toward postmitotic cells....

06/05/2026

A new study published in Nature Structural & Molecular Biology provides important insights into how cells repair DNA damage arising from collapsed replication forks—one of the most significant threats to genome stability and a key driver of cancer, aging, and genetic disease. The authors demonstrate that repair outcomes differ dramatically depending on whether a single replication fork collapses or whether converging forks fail simultaneously, revealing previously unappreciated complexity in DNA damage response pathways.

Here the authors show that collapse of single replication forks causes recombination, end fusions or degradation but does not restart DNA synthesis. In contrast, collapse of convergent forks completes DNA synthesis through error-prone double-strand break repair.

05/24/2026

The emergence of daraxonrasib and related pan-RAS(ON) inhibitors represents a major advance in targeting historically “undruggable” RAS-driven cancers. This drug is showing substantial promise in pancreatic cancer. While these agents are showing encouraging clinical activity, biology suggests that combination strategies may ultimately be required for maximal and durable responses. One intriguing direction is the integration of DNA damage-inducing therapies, including topoisomerase poisons, which may synergize with RAS pathway suppression by increasing replication stress and genomic instability in already vulnerable tumor cells. As the field evolves, mechanistic combination studies that integrate signaling inhibition with DNA damage biology may become increasingly important in defining next-generation therapeutic regimens.

05/12/2026

Find out about DNA Gyrase Enzyme available from TopoGEN

TopoGEN: Preeminent Cancer Research Products Including High Quality Topoisomerase Enzymes & DNA Gyrase

04/14/2026

There is an increasingly important enabling technology in gene therapy and nucleic acid delivery: the use of DNA Gyrase to generate highly supercoiled plasmid DNA, a topology that is strongly correlated with improved delivery efficiency and functional expression and enhanced efficiency in gene therapy.

TopoGEN: Preeminent Cancer Research Products Including High Quality Topoisomerase Enzymes & DNA Gyrase

04/03/2026

# # DNA Isn’t Just a Blueprint—It’s Alive with Motion!!

A new paper in *Science* is shining light on something truly fascinating:
https://www.science.org/doi/10.1126/science.adv0134

**DNA is not just a static code—it twists, coils, and moves as our cells read it.**

When genes are turned on, the DNA helix actually becomes **overwound and underwound**—a bit like a phone cord twisting as it’s stretched. These physical changes, called *DNA supercoiling*, play a big role in how genes are expressed.

What’s especially meaningful to us at TopoGEN is that this idea has deep roots.

Back in 1985, we published one of the first studies showing that an enzyme called **Topoisomerase I (Top1)** is concentrated in the nucleolus—the busiest region of the cell where ribosomal RNA is made at very high rates.
👉 Topoisomerase I localization at rRNA genes EMBO Journal 1985

At the time, we proposed something new:
**Top1 helps cells manage the stress created when DNA is actively being transcribed.**

We didn’t stop there.

In follow-up work, we showed that Top1 has a strong preference for **supercoiled DNA**—the very form DNA takes when genes are actively being used:
👉 Topoisomerase I affinity for supercoiled DNA 1985 follow-up study

Together, these findings helped establish a now widely accepted concept:
**DNA structure and motion are just as important as DNA sequence.**

# # # Why this matters today

Modern research is confirming that these twists and turns in DNA aren’t just incidental—they actually help control how genes are turned on and off.

And enzymes like Top1 are essential for keeping this process running smoothly.

# # # Where TopoGEN comes in

For decades, TopoGEN has provided scientists with the tools to study these processes directly—helping researchers understand how DNA works in real time, and how it can be targeted in diseases like cancer.

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**From foundational discoveries in the 1980s to cutting-edge research today, one thing is clear:**

👉 DNA is dynamic.
👉 Structure matters.
👉 And we’re still uncovering how it all works.

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During eukaryotic transcription, RNA polymerase II (Pol II) must overcome nucleosome obstacles and, because of DNA’s helical structure, must also rotate relative to DNA, which generates torsional stress. However, there is limited understanding of how Pol ...

04/02/2026

Recent work published in Geroscience highlights an unexpected connection between **topoisomerase inhibition and longevity biology. THIS IS HUGE!!

Using a transcriptomics-driven discovery platform, researchers identified topoisomerase drugs (like amonafide), are a novel class of geroprotective agents. In C. elegans, these compounds improved mobility during aging and extended lifespan by activating conserved stress-response pathways, including the mitochondrial unfolded protein response (UPRmt).

This is a striking shift in perspective: drugs traditionally viewed through an oncology lens (e.g., Top2 poisons) may also modulate fundamental aging pathways linked to genome stability, mitochondrial signaling, and cellular defense programs!!

For those working at the interface of DNA topology, genome maintenance, and translational aging research, this opens many compelling opportunities & TopoGEN is uniquely positioned to enable and accelerate this line of investigation.

Our portfolio of highly purified human topoisomerases (Top1, Top2α/β), DNA substrates (including kDNA), and mechanistic assay platforms (relaxation, decatenation, and ICE assays) allows researchers to:

• Dissect **Top2-dependent vs. off-target drug mechanisms**
• Quantify cleavage complex formation in cells (critical for “poison” vs. catalytic inhibitor classification)
• Translate in vivo findings into **human-relevant biochemical and cellular systems**
• Rapidly screen next-generation compounds for **geroprotective vs. genotoxic profiles**

As the field moves from worm models toward human systems, **mechanistic clarity will be the gating factor**—and that is precisely where TopoGEN delivers.

If you are exploring topoisomerases in aging, neurodegeneration, or genome stability, we welcome the opportunity to collaborate.

Here’s a curated set of high-signal hashtags tailored for reach in biotech, aging, and drug discovery circles:



[1]: https://pmc.ncbi.nlm.nih.gov/articles/PMC12181488/?utm_source=chatgpt.com "Topoisomerase inhibitor amonafide enhances defense ... - PMC"

Aging is a major risk factor for disease, and developing effective pharmaceutical interventions to improve healthspan and promote longevity has become a high priority for society. One of the molecular pathways related to longevity in various model ...

12/09/2025

TOP2B Creates Hidden Hotspots of Cancer Mutations—And TopoGEN’s new Technology Reveals Their Active Sites on the Genome of the Cancer Cell.

A major new Nature Communications study has reshaped how we understand cancer genome evolution. The authors generated genome-wide maps of TOP2B binding directly from human tumors, revealing that this enzyme—long known for resolving DNA topological stress—actually marks hotspots of mutation, structural breakpoints, and cancer-driving lesions across the genome .

These TOP2B sites cluster at promoters, enhancers, 3-D chromatin anchors, and highly transcribed loci, including drivers such as TP53, MYC, FOXA1, EGFR, VHL, and the non-coding driver RMRP. Mutations at these "TOP2B footprints" are not random: they arise where the enzyme must cleave and re-ligate DNA to resolve torsional stress—an inherently dangerous step. When this process stalls or misfires, persistent cleavage complexes form, seeding double-strand breaks, structural variants, and recurring driver mutations that fuel tumor initiation and progression.

Why This Matters for Precision Oncology

The study demonstrates that TOP2B catalytic activity itself is a mutational process in cancer, distinct from TOP2A and deeply intertwined with transcription, chromatin looping, and regulatory DNA architecture. Mapping where TOP2B is chemically attached to DNA inside tumor cells is now essential for understanding why certain genomic sites become evolutionary pressure points.

Where TopoGEN’s ICE Assay Becomes a Transformative Tool

The TopoGEN ICE Assay (Cat. #1020) is uniquely positioned to operationalize these discoveries.
Unlike ChIP or sequencing-only methods, ICE directly captures and quantifies trapped TOP2–DNA covalent complexes inside the cell, enabling:

Isoform-specific detection (TOP2A vs. TOP2B) under native intracellular conditions where the enzymes are actively breaking and resealing DNA.

High-resolution mapping of TOP2B catalytic stress points on genomic DNA.

Mechanistic insight into how therapeutic TOP2 poisons or oncogenic signaling pathways stabilize cleavage complexes.

Integration with genomics and bioinformatics pipelines to identify the exact sequences where TOP2B becomes mutagenic.

In other words, ICE is the only practical biochemical method that gives researchers the same mechanistic visibility that this landmark tumor-profiling study reveals—but in a controllable experimental format.

A New Direction for Cancer Research

By pairing the insights of large-scale tumor genomics with the mechanistic precision of ICE, investigators can now:

Pinpoint functional TOP2B cleavage hotspots in their own cancer models.

Discover why certain promoters or enhancers collapse into mutation clusters.

Evaluate new therapeutics that modulate TOP2B activity or protect fragile genomic sites.

Translate genomics findings into actionable drug discovery and biomarker strategies.

The cancer genome is not a passive victim of random damage—TOP2B’s catalytic footprint is a blueprint of genomic vulnerability. And the TopoGEN ICE assay is the tool that brings this blueprint into the laboratory.