Extracellular vesicles, or EVs, are tiny membrane-bound particles released by cells into surrounding tissues and body fluids. Although they are only a fraction of the size of a cell, they can carry proteins, lipids and nucleic acids that alter the behaviour of recipient cells. Tumours exploit this communication system, releasing circulating tumour-derived extracellular vesicles, known as ctEVs, that can help reshape distant tissues, support tumour growth and influence how cancer responds to treatment. A study published in Nature Cell Biology now reports that the release and molecular composition of these tumour-associated vesicles fluctuate according to the time of day. The findings introduce a method for tracking newly produced ctEVs in narrow time windows and suggest that the daily biological clock could become an important consideration in cancer therapy.
The challenge has been that conventional methods generally measure the total population of EVs present in the circulation at a given moment. That population is a mixture of vesicles released at different times, from different tumour cells and potentially through different cellular pathways. Because EVs can remain in the bloodstream after secretion, a sample collected in the morning may contain particles produced hours earlier. This makes it difficult to determine when vesicles were generated and whether their biological properties change over the course of a day. The research team addressed this problem by developing ctEV-CLOCK, a strategy designed to isolate nascent tumour-derived vesicles according to their time of biogenesis. The approach provides approximately 12-hour resolution, allowing researchers to compare vesicles generated during distinct daily phases rather than treating circulating EVs as a single, static population.
ctEV-CLOCK combines two forms of molecular engineering. The first is metabolic glycoengineering-based timestamping, a technique that introduces chemically addressable sugar residues into newly synthesized cell-surface and secreted molecules. In practical terms, tumour-bearing animals receive a metabolic precursor that is processed by cells and incorporated into glycans associated with vesicles produced during a defined labelling interval. These glycans function as molecular timestamps. Vesicles generated while the precursor is available acquire a chemical handle that can later be detected or captured. The method therefore records when a vesicle was produced without requiring researchers to observe the secretion event directly, which would be difficult inside a living organism.
The second component is tumour-marker-guided selective click tagging. Click chemistry refers to highly selective reactions that join two chemical groups rapidly and under biologically compatible conditions. In this strategy, the timestamped vesicles are subjected to a click reaction that attaches a detectable or isolatable tag. A tumour-associated marker provides an additional layer of selectivity, helping distinguish ctEVs from the much larger background of vesicles released by normal tissues. Combining a time-dependent chemical label with tumour-specific recognition enables researchers to enrich vesicle populations generated within a defined interval. The resulting samples can then be examined for abundance, protein content and biological activity, providing a more precise view of how the tumour secretome changes over the daily cycle.
Using this platform in several mouse tumour models, the investigators observed circadian oscillations in the number of ctEVs found in circulation. The pattern was not limited to a single experimental tumour type, suggesting that time-dependent vesicle release may represent a broader feature of tumour biology rather than an isolated behaviour of one model. Circadian rhythms are generated by interconnected molecular clocks that coordinate physiology over roughly 24 hours, influencing metabolism, hormone signalling, immune activity and tissue repair. The new results indicate that these clock-controlled processes also extend to the production or release of tumour-derived vesicles. The study’s 12-hour sampling framework does not resolve every minute of the secretion cycle, but it is sufficient to reveal pronounced differences between daily phases that would be obscured in conventional measurements.
The oscillation involved more than vesicle abundance. ctEVs collected at different times also displayed differences in their functional properties, indicating that the tumour may release molecularly distinct vesicle populations during separate phases of the day. EVs are biological delivery systems: their lipid membranes protect cargo, while surface proteins can guide interactions with particular recipient cells. Changes in the proteins displayed on a vesicle’s surface, or packaged inside it, may therefore alter where the particle travels and how it affects its targets. According to the study, time-of-day-dependent shifts in ctEV protein profiles accompanied the changes in abundance. Such variations could influence processes including communication between tumour cells, conditioning of distant tissues and the ability of cancer cells to adapt to therapeutic stress.
The researchers next examined whether these biological rhythms could affect treatment response. Targeted therapies are designed to inhibit specific molecular drivers that cancer cells depend on, but their effectiveness can vary with drug exposure, tumour-state changes and interactions with the surrounding microenvironment. The study found that synchronizing targeted treatment with the period when ctEV protein abundance was highest markedly improved therapeutic efficacy in the tested models. This result does not mean that ctEVs alone determine treatment outcome, nor does it establish an immediately transferable dosing schedule for patients. Instead, it suggests that vesicle-mediated signalling may create a time-dependent layer of vulnerability. Administering therapy when tumour-derived vesicle activity or cargo is at a relevant peak could potentially disrupt communication pathways more effectively than giving the same treatment at an arbitrary time.
The work also broadens the concept of cancer chronotherapy. Most discussions of circadian treatment scheduling have focused on the daily rhythms of immune cells, drug metabolism or the direct molecular targets of anticancer medicines. ctEV-CLOCK points to another potential determinant: the timing of intercellular messages released by the tumour itself. Because ctEVs circulate through the body, their rhythmic secretion could connect local tumour clocks with distant organs and influence the condition of tissues that later support metastasis. Time-specific differences in vesicle composition might also affect how stromal cells, blood-vessel cells or immune populations respond to the tumour. If similar patterns are confirmed in human cancers, measuring ctEV timing and cargo could eventually help identify when a tumour is most communicative or most susceptible to therapies that interfere with its signalling network.
Several questions remain before the findings can be translated into clinical practice. Human tumours are genetically and biologically heterogeneous, and their circadian rhythms may be altered by sleep disruption, feeding patterns, hormonal status, treatment schedules and disease progression. The composition of circulating EVs is also influenced by organs throughout the body, making tumour-specific enrichment essential for meaningful analysis. Future studies will need to determine whether the oscillations detected in mice are preserved in patients, whether different cancer types peak at different times and which specific vesicle proteins are responsible for the observed therapeutic effects. It will also be important to test whether ctEV measurements can be developed into practical blood-based biomarkers. For now, the study establishes a technical and conceptual framework: tumour-derived vesicles are not simply released continuously into the bloodstream, but may be produced in a clock-regulated pattern that shapes their function and could help determine the best time to treat cancer.
Subject of Research: Circadian dynamics of circulating tumour-derived extracellular vesicles and their influence on targeted cancer therapy.
Article Title: Circadian control of circulating tumour-derived extracellular vesicle secretion affects targeted therapy efficacy
Article References: Chen, M., Zhang, Y., Zhu, Y. et al. Circadian control of circulating tumour-derived extracellular vesicle secretion affects targeted therapy efficacy. Nat Cell Biol (2026). https://doi.org/10.1038/s41556-026-02047-y
Image Credits: AI Generated
DOI: https://doi.org/10.1038/s41556-026-02047-y
Keywords: extracellular vesicles, circulating tumour-derived extracellular vesicles, ctEV-CLOCK, circadian rhythm, metabolic glycoengineering, click chemistry, tumour biology, cancer chronotherapy, targeted therapy, vesicle protein cargo
