Imagine we have an extremely effective medicine, but its use is like shooting a sparrow with a cannon. It destroys the target but injures healthy cells in the process. Is it possible to deliver it safely and precisely—like a surgical sniper? Scientists from Wroclaw have just shown that yes. Their secret weapon is electricity.

What is jasplakinolide?

Let's start with a substance with a difficult name - jasplakinolide. It's a natural chemical compound extracted from marine sponges from the Pacific region. In the world of cells, jasplakinolide is like a general reorganizing an army: it affects the so-called cytoskeleton - the inner skeleton of cells made of actin. It stabilizes the F-actin filaments and disrupts the natural cell movement, division, and growth processes for tumors, which means death. However, the problem is that the drug affects all cells, including healthy ones.

- Jasplakinolide, which acts as a stabilizer of actin filaments, may indeed be effective in treating cancers that are characterized by a highly developed cytoskeleton, explains Dr Anna Szewczyk from the Department of Molecular and Cellular Biology, Wroclaw Medical University.
- This could be particularly important in cases of cancers with high invasiveness, such as breast cancer, lung cancer, or gliomas, where the cytoskeleton plays a key role in the processes of cancer cell spread - Dr Szewczyk says.

Rhabdomyosarcoma - the enemy in the shadows

Rhabdomyosarcoma (RMS) is a rare but aggressive neoplasm of the striated muscles. It most commonly affects children between the ages of 1 and 10, developing in the head, neck, genital organs, or extremities. It is the most common soft tissue sarcoma in children and adolescents, accounting for about 50% of all sarcomas in this age group. Standard treatment—chemotherapy, radiation therapy, and surgery—is sometimes effective but not consistently effective and not without side effects.

A study by a team led by Dr Anna Szewczyk of Wroclaw Medical University focused on RMS.

Wojciech Szlasa M.D., Prof. Julita Kulbacka, Ph.D. Anna Szewczyk

Wojciech Szlasa M.D., Prof. Julita Kulbacka, Ph.D. Anna Szewczyk

Their idea? Use jasplakinolide, but only where needed. This is where electroporation enters the scene.

Electroporation - opening cells with current

Electroporation (EP) is a technique known to molecular biologists and biomedical engineers. It involves applying short, controlled electrical pulses to cells, temporarily "expanding" their cell membranes. It's like quickly opening a door to the cytoplasm - drugs, genes, or other molecules can enter through this door.

- In our team, we are testing various methods that support selective drug delivery to cancer cells - says Prof. Julita Kulbacka from the Department of Molecular and Cellular Biology, Wroclaw Medical University - We are investigating several other technologies that enable targeted drug delivery, including nanocarriers - from liposomes and polymer nanoparticles to smart protein carriers. We are also working on sonoporation, magnetoporation, and even photodynamic therapy. However, PEF (Pulsed Electric Field) is the most clinically advanced technology today, and she points out that it has more than 20 years of experience in electrochemotherapy.

Why are researchers so keen on electroporation?

First of all, it's a method already well-known and used—there is no need to build it from scratch. The pulse-generating devices and electrodes are approved for clinical trials, and the electrochemotherapy procedure itself has more than two decades of experience treating patients. This provides a solid foundation.

Second - and equally important – electroporation works effectively and predictably. The pulses only open the cell membrane, allowing drugs to enter, after which the membrane "closes." Importantly, healthy cells are much less sensitive to this process than cancerous ones - a considerable advantage in topical therapy.

And one more thing — electroporation can be easily combined with other modern solutions, such as drug nanocarriers. Thus, choosing one path is unnecessary — they can be combined to create "tailor - made" therapies, with the method as a proven starting point.

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The perfect combination - jasplakinolide + current

The study used three cell lines: RD (RMS cancer cells), CHO-K1 (hamster ovary cells), and C2C12 (mouse muscle cells). This allowed us to compare how the therapy works on cancer and healthy cells.

Immunofluorescence visualization of vimentin in a malignant cell line after electroporation with jasplakinolide.

The results indicated that the combination of jasplakinolide and electrical pulses dramatically reduced the survival of cancer cells while having almost no effect on healthy cells. At the microscopic level, we could see the "disintegration" of their cytoskeleton - as if the internal scaffolding had collapsed.

- We also observed changes in the expression of pan -cadherin, which is responsible for cell adhesion - adds Dr. Szewczyk. Fragmentation of cadherins can mean a loss of the ability to form intercellular connections, which impairs a tumor's ability to metastasize.

What does this mean for patients?

It's not yet a combination that will enter hospital rooms — however, the results point to new strategies for treating pediatric cancers. Instead of systemic chemotherapy, which damages healthy cells, we could use precise, topical drug applications supported by electrical pulses.

- Electroporation provides a versatile platform for delivering a variety of molecules - from classical cytostatics to RNA/siRNA to proteins and antibodies used in immunotherapy - explains Wojciech Szlasa, Faculty of Medicine UMW. - Particularly hopeful is the possibility of local delivery of immunomodulatory drugs, such as checkpoint inhibitors or cytokines, which could reduce their systemic toxicity. Research is also underway to integrate PEFs with gene therapies, such as introducing CAR receptors into T cells without the need for viruses.

Is it safe?

Yes, but with a caveat: the research was conducted in vitro at this point. The following steps are animal tests and potentially clinical trials in humans.

Under laboratory conditions, everything is predictable - researchers know exactly what cells are subjected to electrical impulses and can control almost every parameter. But the human body - especially a child's - is an entirely different story. In young patients, a spectrum of variables must be considered: from the specifics of the tumor tissue and its environment to the individual anatomy to how the body responds to drugs. Even something seemingly simple as electrical conductivity can vary depending on tumor location or tissue hydration.

- The biggest challenge in translating the electroporation method from an in vitro model to clinical use - especially in children - is the complexity of the human body, which laboratory models do not capture - Dr. Anna Szewczyk explains. - In a child's body, we must consider several additional factors: the tumor microenvironment, tissue conductivity, the patient's anatomy, and even the need for general anesthesia.

How children metabolize drugs is also essential—their bodies work differently than adults, which affects the effectiveness and safety of therapy. Finally, striated cell sarcoma is a rare cancer, so large clinical trials are hard to come by. A new method cannot be easily introduced into clinical practice without data from large, randomized trials. All this means that while electroporation looks promising, its path to pediatric oncology must be thoughtful, careful, and well - documented.

3D models and immunotherapy - the future of targeted therapies

New research models are also essential to implement therapies in the clinic.

- We want to move away from simplified two-dimensional culture systems," says Wojciech Szlasa. - Therefore, we are developing 3D models that better mimic the architecture and behavior of real tumors. Tumor spheroids allow us to study how the effectiveness of therapy changes under different microenvironment conditions, he explains.

At the same time, the researchers are exploring the possibility of combining electroporation with immunotherapy - such as local delivery of cytokines or checkpoint inhibitors. This is a solution that can not only improve the effectiveness of the therapy but also minimize side effects by limiting the impact of the drugs to the tumor site only.

- Looking at the prospects for the next ten years, we expect several key developments - predicts Prof. Kulbacka - First, precision and personalized therapies, that is, combining several bioelectrochemical techniques in a single protocol - from classical electrochemotherapy to irreversible electroporation and plasma ablation - to select the ideal combination of pulse, drug and immunomodulator dose for a particular patient. Second, with increasingly precise electrodes, we will reach deep tumors that today are beyond the reach of a surgeon's knife or radiation, he points out.

Another direction is miniaturization - new, flexible, and precise pulse delivery systems are expected to enable therapy in the operating room and the outpatient setting. The fourth is the use of artificial intelligence. - Machine learning algorithms will analyze signals from biosensors in real-time and suggest how to adjust the parameters of the electric field to maximize effectiveness and minimize toxicity - Prof. Kulbacka adds.

What does this mean for the patient? - First, greater precision and effectiveness, less invasiveness, and the possibility of fully personalizing the therapy. And since electrical impulses can additionally stimulate our immune system, we expect increasingly better treatment results.

Why do children need better treatments?

Because pediatric cancers, although rare, are challenging to treat - the child's body is in the stage of intense development and very sensitive to toxic substances. Precision therapies, such as the combination of the natural drug jasplakinolide with electroporation, could replace or supplement chemotherapy in the future, increasing the chances of a complete cure with fewer side effects.

Cancer is still one of modern medicine's most significant challenges. But thanks to interdisciplinary research, such as that from Wroclaw Medical University, there is hope for safer and more targeted treatments.

Jasplakinolide and electroporation could become a duo that—like a surgeon and a sniper in one—accurately hits cancer cells while sparing healthy ones. Is this science fiction? Perhaps today, but tomorrow—maybe the standard.

D. Sikora

FAQ: Precision at the level of the cell

What is rhabdomyosarcoma (RMS)?

Rhabdomyosarcoma is a rare and aggressive type of soft tissue cancer that primarily affects children and adolescents. It originates from immature skeletal muscle cells and can appear in various body parts. Symptoms can include a painless mass, swelling, or localized pain and can vary depending on the tumor's location.

What is jasplakinolide, and how does it affect cells?

Jasplakinolide is a natural cyclic depsipeptide isolated from marine sponges. It has shown potent cytotoxic (cell-killing) effects, particularly at the nanomolar level. Its primary mechanism of action involves disrupting the actin cytoskeleton within cells. It promotes the polymerization of F-actin and/or inhibits its depolymerization, which alters the structure and function of the cytoskeleton, impacting cellular processes like shape and movement.

How does electroporation enhance jasplakinolide delivery?

Electroporation (EP) is a biophysical technique that uses brief electrical pulses to create temporary pores in cell membranes. This transient permeabilization allows for increased uptake of external molecules, including therapeutic agents like jasplakinolide, into the cells. Combining jasplakinolide with electroporation is being explored to improve its targeted delivery to cancer cells.

What is the potential significance of jasplakinolide's interaction with monomeric and filamentous actin?

Computational docking studies suggest that jasplakinolide can interact with individual actin units (monomeric actin) and the assembled chains of actin (filamentous actin). This finding hints at a potential dual mechanism of action for jasplakinolide involving the known stabilization of actin filaments and interactions with monomeric actin. Further research is needed to fully understand this dual binding mode's biochemical implications.

How is rhabdomyosarcoma typically treated?

The management of RMS usually involves a combination of treatments, including surgery to remove the tumor, chemotherapy to kill cancer cells and radiation therapy. Recent advancements are also exploring targeted therapies and immunotherapies as promising new approaches.

Why is targeted delivery of jasplakinolide important?

While jasplakinolide has shown promising anti-tumor activity, it can also have systemic side effects in the body. Therefore, delivering it specifically to cancer cells is crucial to maximize its therapeutic impact while minimizing harm to healthy tissues. This selective delivery can potentially reduce side effects associated with its clinical use.

What were the study's key findings regarding jasplakinolide and electroporation in rhabdomyosarcoma cells?

The study found that combining jasplakinolide (JSP) with pulsed electric fields (PEFs) significantly enhanced the cytotoxic effects on rhabdomyosarcoma (RD) cells compared to either treatment alone. This combined approach led to notable changes in the cytoskeleton, particularly the disruption of actin filaments and pan-cadherin, and a significant reduction in RD cell viability. Regular cell lines tested showed minimal effects, suggesting a selective impact on cancer cells. How does the combined treatment of jasplakinolide and electroporation affect the cytoskeleton? The combination of jasplakinolide and electroporation significantly disrupts the actin cytoskeleton in sensitive cancer cells like RD cells, forming actin aggregates and reducing stress fibers. It also affects other cytoskeletal components like pan-cadherin, potentially leading to the destabilization of cell-cell connections. These changes can impair crucial cellular processes such as migration and adhesion. Normal muscle cells (C2C12) showed higher resistance to these cytoskeletal changes.

This material is based on the article

Optimizing Jasplakinolide delivery in rhabdomyosarcoma cells using pulsed electric fields (PEFs) for enhanced therapeutic impact

Anna Szewczyk, Nina Rembiałkowska, Marta Migocka-Patrzałek, Wojciech Szlasa, Agnieszka Chwiłkowska, Małgorzata Daczewska, Vitalij Novickij, Julita Kulbacka

Bioelectrochemistry

Web. A. Hasiak

Photos: Tomasz Modrzejewski, freepik.com

Precision at the level of the cell

Electrical impulses striated cell sarcoma