Caterpillar Fungus Compound Gets a Nanoparticle Upgrade to Attack Breast Cancer

A compound extracted from a fungus long prized in traditional medicine may finally be ready to realize its anticancer potential, thanks to a tiny fat-based delivery vehicle. Cordycepin, a naturally occurring adenosine analogue produced by the caterpillar fungus Cordyceps militaris and related species, has intrigued cancer researchers for decades because it can trigger cell death in a wide range of tumor types. Yet the molecule has never translated well into the clinic, and the reasons are stubbornly chemical: it is rapidly destroyed in the bloodstream, unstable in acidic environments, and poor at reaching the cells it is supposed to kill. A team of Indian researchers now reports that wrapping cordycepin inside solid lipid nanoparticles substantially overcomes these weaknesses, boosting the compound’s killing power against human breast cancer cells in laboratory tests.

The study, published in the journal Medical Oncology, was led by Saumyadeep Bora and Hitesh Kulhari of the School of Nano Sciences at the Central University of Gujarat, with collaborators from JSS Academy of Higher Education and Research, Parul University, and additional investigators at the Central University of Gujarat. The team set out to solve a problem that has shadowed cordycepin since its earliest characterization: the molecule, formally known as 3′-deoxyadenosine, is structurally almost identical to adenosine, the nucleoside that cells use constantly for energy transfer and signaling. That similarity makes cordycepin a prime target for adenosine deaminase, an abundant enzyme that chemically deaminates the compound and strips it of its anticancer activity within a short time of entering circulation.

The pharmacokinetic obstacles do not stop there. In the stomach, cordycepin encounters a strongly acidic environment that destabilizes the molecule before it can even be absorbed. Once absorbed, its poor pharmacokinetic profile means that little of an administered dose survives long enough or concentrates sufficiently in tumor tissue to do meaningful damage. Conventional cancer therapies suffer from a related cluster of problems, including low bioavailability, non-selective targeting of healthy tissues, and toxicity at the high doses often needed to achieve an effect. Rather than modifying cordycepin itself, the researchers chose to shield it, using a delivery technology that has matured steadily over the past two decades: solid lipid nanoparticles, or SLNs.

Solid lipid nanoparticles are spherical carriers typically tens to a few hundred nanometers across, built from lipids that remain solid at body temperature. A hydrophobic or amphiphilic drug can be dissolved in the molten lipid matrix during preparation, and as the lipid solidifies, the drug becomes entrapped within the particle core. Compared with polymeric nanoparticles, SLNs offer several practical advantages: they can be produced without organic solvents, they use biocompatible excipients, they protect labile molecules from enzymatic and chemical degradation, and they can sustain drug release over extended periods. Their lipid composition also encourages uptake by cell membranes, which are themselves lipid-rich, a property the researchers hoped to exploit to increase how much cordycepin actually gets inside cancer cells.

The team formulated cordycepin-loaded SLNs, abbreviated CSLN, and subjected them to a battery of characterization tests. The resulting particles were monodispersed, meaning they fell within a narrow, uniform size range, a critical property for reproducible drug delivery because particle size governs both circulation behavior and cellular uptake. Imaging and physical characterization confirmed that the particles were spherical and possessed good physical and chemical stability, indicating that the encapsulated drug would not prematurely leak or degrade during storage or transport. Uniform, stable, well-formed particles are the baseline requirement for any nanoformulation to move credibly toward preclinical evaluation, and the CSLN system appears to meet that baseline.

Release behavior was examined under two pH conditions designed to mimic different biological compartments. In acidic conditions, which correspond to the endo-lysosomal environment that nanoparticles encounter after being swallowed by cells, and at physiological pH, which corresponds to the pH of systemic circulation, the CSLN formulations exhibited sustained release of their cargo. This pH-responsive, prolonged release profile serves a dual purpose. In the bloodstream, slow release limits the burst exposure that drives off-target toxicity and rapid clearance. Inside the tumor cell’s acidic vesicles, release is retained, ensuring that the drug is liberated precisely where it can most effectively reach its intracellular targets rather than being lost in the extracellular environment.

The functional payoff of this engineering showed up clearly in cytotoxicity assays against MCF-7 cells, a widely used human breast cancer cell line. Compared with free cordycepin administered in its conventional soluble form, the CSLN formulation significantly enhanced the compound’s cytotoxic effect. The researchers attribute this improvement to two linked mechanisms. First, improved cellular uptake: nanoparticles are internalized by cells through endocytic pathways that free small molecules cannot use, allowing far greater quantities of the drug to accumulate inside the cell. Second, the sustained intracellular release keeps drug levels high at the relevant sites for longer, rather than allowing the compound to be quickly exported or degraded. Together, these effects convert a drug that struggles to reach its target into one that arrives in force and lingers.

Higher intracellular accumulation translated into greater apoptotic activity, meaning the treated cancer cells were more likely to undergo programmed cell death, the controlled self-destruction pathway that cordycepin is known to activate in tumor cells. The study also reported more pronounced clonogenic activity effects, indicating a measurable impact on the ability of surviving cells to proliferate and form colonies. Prior work has established that cordycepin can induce apoptosis in breast cancer cells through caspase-dependent pathways, and can act independently of the estrogen receptor, which matters because MCF-7 cells are estrogen receptor positive and many breast cancers lose endocrine responsiveness over time. The nanoformulation amplifies this intrinsic apoptotic potential simply by getting more intact drug to the right place.

The new work builds on, and differentiates itself from, a growing body of research into cordycepin delivery systems. Previous studies have encapsulated cordycepin in poly(lactic-co-glycolic acid) nanoparticles with improved cytotoxicity and reduced hemotoxicity, loaded it into bovine serum albumin nanoparticles, complexed it with cyclodextrins to improve stability, and formulated CD44-targeted lipid polymer hybrid nanoparticles carrying Cordyceps militaris extracts. Liposome-encapsulated nanocordycepin has also shown enhanced activity in breast and cervical cancer cells. The present study’s contribution is to demonstrate that solid lipid nanoparticles, a simpler and arguably more clinically friendly platform given their biocompatible composition and solvent-free preparation, achieve the same essential goals: protection from adenosine deaminase, resistance to acidic degradation, sustained pH-responsive release, and greater intracellular delivery.

For now, the findings rest on in vitro evidence, and the usual caveats apply: nanoparticle behavior in cell culture does not always predict performance in living animals, where protein adsorption, immune clearance, and tumor heterogeneity complicate the picture. The authors note that their data are available upon reasonable request, and the work was supported by institutional resources at the Central University of Gujarat, JSS Academy of Higher Education and Research, and Parul University, with doctoral fellowships from the University Grants Commission. Even so, the study adds a meaningful data point to one of nanomedicine’s most persistent arguments, that the fastest route to new cancer drugs sometimes runs not through novel molecules but through smarter packaging of old ones. For a compound isolated from a parasitic fungus that has been used in Chinese and Tibetan medicine for centuries, a lipid shell a few hundred nanometers wide may be exactly what it takes to finally make the leap from promising natural product to working therapy.

Subject of Research: Solid lipid nanoparticle delivery of cordycepin for breast cancer therapy

Article Title: Overcoming cordycepin limitations with SLNs-based nanoformulation: formulation development and cytotoxicity evaluation against human breast cancer cells

Article References: Overcoming cordycepin limitations with SLNs-based nanoformulation: formulation development and cytotoxicity evaluation against human breast cancer cells. (n.d.). https://doi.org/10.1007/s12032-026-03407-2

Image Credits: AI Generated

DOI: 10.1007/s12032-026-03407-2

Keywords: cordycepin, solid lipid nanoparticles, breast cancer, MCF-7 cells, nanomedicine, drug delivery, apoptosis, adenosine deaminase, cytotoxicity, natural products, chemotherapy, nanoencapsulation