Liposomal Quercetin Blocks Lung Cancer Spread in Mice, With Liquid Biopsies Tracking Every Step

Lung cancer kills more people worldwide than any other malignancy, and the reason is rarely the original tumor. It is the spread, the silent seeding of cancer cells into the liver, brain, bones, and other organs, that turns a treatable nodule into a terminal disease. Now a team of researchers in India and the United States reports a two-part advance that could reshape how experimental anti-metastatic therapy is delivered and, just as importantly, how its success is measured. In a study published in the journal 3 Biotech, the scientists show that quercetin, a humble plant-derived flavonoid, becomes a dramatically more powerful anti-cancer agent when packaged inside lipid nanoparticles, and that a simple liquid biopsy followed by laboratory culture of the harvested cells can serve as a real-time, minimally invasive readout of whether that therapy is actually working.

The drug at the center of the story is quercetin, a polyphenolic compound found in onions, apples, and many other foods. For years, quercetin has attracted attention for its ability to interfere with cancer cell migration, invasion, and epithelial-to-mesenchymal transition, the biological program that allows stationary epithelial tumor cells to loosen their anchors and drift through tissue. Laboratory studies have repeatedly shown that quercetin can suppress metastatic behavior across prostate, ovarian, breast, and glioblastoma models. Yet the compound has a stubborn flaw that has kept it out of serious clinical consideration: poor bioavailability. Free quercetin is poorly soluble, unstable, and rapidly cleared, meaning that very little of an administered dose ever reaches the tumor in an active form.

The research team, led by V. Jenitha and colleagues at Karunya Institute of Technology and Sciences in Coimbatore, tackled that limitation with a liposomal formulation the group calls Lipo-Que. Liposomes are microscopic spherical vesicles built from phospholipid bilayers, the same structural motif that encloses living cells. By dissolving quercetin within these lipid shells, the researchers shield the fragile molecule from degradation, improve its circulation time in the bloodstream, and enhance its delivery to tumor tissue. The formulation builds on the team’s earlier work, published in the Journal of Drug Delivery Science and Technology, in which they optimized the cholesterol content of the liposomes for intravenous administration and demonstrated the formulation’s safety profile in mice.

To test whether the nano-packaged quercetin could actually restrain metastasis, the researchers turned to a well-established mouse model of lung cancer induced by benzo(a)pyrene, a potent carcinogen found in tobacco smoke and charred foods. Benzo(a)pyrene drives lung tumor formation through well-characterized mutagenic and inflammatory pathways, and it also promotes metastatic signaling through mechanisms involving nuclear factor kappa B, making it a demanding test bed for any anti-metastatic drug. Animals with induced lung cancer were treated with either free quercetin or the liposomal version, and the outcomes were compared across a battery of in vitro and in vivo assays.

The results were striking. In cell migration assays conducted in the laboratory, Lipo-Que inhibited the movement of cancer cells far more effectively than free quercetin, with the difference reaching statistical significance at the stringent threshold of P less than or equal to 0.001. In the living animals, the liposomal formulation produced a marked reduction in lung tumor burden, the number and extent of tumor foci scattered through the lung tissue. Most dramatically, the treatment achieved complete suppression of hepatic metastasis, meaning that the livers of Lipo-Que-treated mice showed no evidence of the cancer colonies that had taken hold in untreated and free-quercetin-treated animals. For a disease whose lethality is defined by spread to distant organs, that single finding carries considerable weight.

But the second half of the study may prove to be its most influential contribution. Measuring whether an anti-metastatic drug works has traditionally required invasive procedures: surgical biopsy of tumor tissue, histopathological examination, or terminal analysis of organs. The researchers instead asked whether the body’s own fluids could tell the story. Liquid biopsy, the analysis of tumor-derived cells and biomarkers circulating in blood, bronchoalveolar lavage fluid, or tracheal secretions, has gained momentum in oncology as a way to detect and monitor cancer without a scalpel. Circulating tumor cells shed from primary tumors and metastatic sites can be captured and characterized, and their surface markers reveal a great deal about the state of the disease.

The team focused on a protein called EpCAM, the epithelial cell adhesion molecule, which is overexpressed on many epithelial-derived cancer cells and is widely used to identify metastatic tumor cells in fluid samples. Using fluorescence-activated cell sorting, a flow cytometry technique that quantifies and isolates cells bearing specific surface markers, the researchers counted EpCAM-positive and epithelium-like cells in the liquid biopsy samples of each treatment group. In the mice receiving Lipo-Que, these populations dropped significantly, again at the P less than or equal to 0.001 level, indicating that the treatment was not merely shrinking tumors but reducing the pool of cells capable of seeding new colonies.

The truly novel step came next. Rather than discarding the harvested cells after counting them, the researchers cultured them outside the body for seven days, an ex vivo approach that turns a diagnostic snapshot into a functional test. Cells from untreated cancer-bearing mice proliferated robustly in culture, adhering to the growth surface and expanding steadily, a signature of viable, aggressive metastatic potential. Cells from mice treated with free quercetin showed some restraint, but the inhibition was inconsistent. Cells from the Lipo-Que group, by contrast, displayed sustained growth inhibition from the very first day of culture through day seven, and the mean number of adherent cells was significantly reduced. Under the microscope, the treated animals’ cells showed shrunken, fragmented morphological features characteristic of apoptosis, the controlled cell death program that cancer cells must evade to survive dissemination.

This combination of cell morphology analysis, EpCAM quantification, and ex vivo culture constitutes what the authors describe as therapeutic indexing, a functional, minimally invasive platform for assessing anti-metastatic efficacy as treatment unfolds. The concept has immediate appeal for precision oncology. If a patient’s circulating tumor cells can be harvested, cultured, and challenged in the laboratory, clinicians could in principle gauge whether a therapy is suppressing metastatic potential within days rather than waiting months for imaging scans to reveal whether new lesions have appeared. The approach also sidesteps a known blind spot of EpCAM-based detection alone, since tumor cells undergoing epithelial-to-mesenchymal transition can shed the marker; pairing molecular phenotyping with functional culture provides a more complete picture of residual metastatic risk.

Cautious optimism is the appropriate posture. The findings come from a carcinogen-induced mouse model, and the long road from rodent studies to human trials is littered with therapies that succeeded in animals but failed in patients. Quercetin itself has shown biphasic effects at different concentrations in some studies, and questions about optimal dosing, long-term safety, and delivery to human tumors remain open. Nevertheless, the study demonstrates two ideas worth watching. First, that nanotechnology can rescue a dietary compound with genuine anti-metastatic biology from its own pharmacological weaknesses, converting it into a targeted therapeutic candidate. Second, that the fluid a patient already carries, whether blood or airway lavage, can be transformed into a living laboratory where the effectiveness of that therapy is tested directly on the patient’s own cancer cells. If those two principles survive translation, the management of metastatic lung cancer, the deadliest phase of the world’s deadliest cancer, could become measurably more responsive, more personal, and far less invasive.

Subject of Research: Liposomal quercetin nanotherapy and liquid biopsy-based functional assessment of metastasis suppression in experimental lung cancer

Article Title: Liquid biopsy cell analysis and ex vivo culture as effective methods of therapeutic indexing of metastasis in B[a]P-induced lung cancer mice for an active targeted quercetin therapy

Article References: Liquid biopsy cell analysis and ex vivo culture as effective methods of therapeutic indexing of metastasis in B[a]P-induced lung cancer mice for an active targeted quercetin therapy. (n.d.). https://doi.org/10.1007/s13205-026-05071-9

Image Credits: AI Generated

DOI: 10.1007/s13205-026-05071-9

Keywords: lung cancer, liquid biopsy, quercetin, liposomes, nanomedicine, metastasis, EpCAM, ex vivo culture, circulating tumor cells, drug delivery, precision oncology, benzo(a)pyrene