3D Mesothelioma Spheroids Reveal Why Chemo Often Fails
An Australian team built a 3D mesothelioma spheroid model that mimics tumor resistance to chemo. PI3K/AKT and Notch signaling drive the resistance.
A team of Australian researchers has built a three-dimensional model of pleural mesothelioma that reproduces how patient tumors resist standard chemotherapy, identifying signaling pathways that may explain why most patients eventually progress on the cisplatin and pemetrexed combination that has been the first-line standard of care for two decades.
The study, published in Scientific Reports in February, established that 3D spheroids of mesothelioma cells survive chemotherapy at higher doses than flat-dish 2D cultures of the same cells, with reduced apoptosis and altered cell-cycle profiles. The findings position the spheroid system as a more physiologically relevant platform for testing new mesothelioma drugs.
Why 2D Cultures Fall Short
Most preclinical cancer drug research uses 2D cell cultures grown on plastic dishes. Drugs are screened for activity, then advanced toward clinical trials based on those results. The model is fast and inexpensive, but it does not replicate the conditions inside an actual tumor, where cells form three-dimensional clusters with limited oxygen, restricted nutrient access, and complex interactions with surrounding tissue.
The translational gap shows up in clinical trial results. Many mesothelioma drug candidates that look promising in 2D screens fail to show meaningful benefit in patients. The Australian team set out to build a model that more closely matches the tumor microenvironment people with mesothelioma actually have.
What the 3D Model Showed
The researchers grew mesothelioma cells from multiple histological subtypes as 3D spheroids, then tested them against cisplatin combined with pemetrexed, the chemotherapy doublet that has been the standard first-line regimen since 2003. The 3D cultures required substantially higher drug concentrations to achieve the same cell-kill seen in 2D, with elevated IC₅₀ values across subtypes.
Apoptosis, the form of programmed cell death triggered by chemotherapy, was reduced in the spheroids. Cell-cycle profiling showed the 3D cultures shifted toward a slower-cycling state, consistent with quiescent tumor cells that evade drugs targeted at dividing cells.
Seahorse metabolic analysis, which measures real-time cellular energy production, found that the spheroids had suppressed oxidative phosphorylation, the mitochondrial pathway that normally generates most of a cell’s energy. Unexpectedly, the cells did not compensate by upregulating glycolysis, the alternative energy pathway many cancers use under stress. The combined pattern fits the hypoxic and nutrient-restricted conditions described in actual mesothelioma lesions.
IC₅₀ is the concentration of a drug required to inhibit a biological process by half. Higher IC₅₀ values mean a drug is less effective. Apoptosis is a controlled form of cell death that chemotherapy normally triggers in cancer cells.
The Signaling Pathways That Matter
Proteomic analysis of the 3D cultures identified two signaling networks that were upregulated in spheroids compared to 2D cells: PI3K/AKT and Notch/VEGF. Both pathways are known drivers of cancer cell survival and resistance to therapy in other tumor types.
PI3K/AKT signaling controls cell growth, survival, and metabolism. Drugs targeting this pathway are approved or in development for several cancers. Notch signaling regulates how cells differentiate and communicate, and Notch activation has been linked to chemotherapy resistance in lung and breast cancers. VEGF promotes blood vessel growth around tumors, supporting their nutrient supply.
The team also identified subtype-specific microRNA signatures in the spheroids that closely matched data from patient tumor samples, suggesting the 3D model preserves disease-relevant gene regulation that gets lost in 2D culture.
What This Means for Future Treatments
Histological assessment of mouse xenografts confirmed that the 3D spheroid model captured the fibrotic stroma, areas of necrosis, and treatment-response patterns seen in patient tumors. That validation supports using the model as a screening platform for new drugs and combination regimens.
For patients today, the findings do not change the standard of care. Cisplatin-pemetrexed remains the foundation of first-line chemotherapy, and recent approvals have added immunotherapy options including nivolumab plus ipilimumab and the pembrolizumab-chemotherapy combination. But the work helps explain why chemotherapy alone often fails to produce durable responses, and it points to PI3K/AKT and Notch as candidate pathways for future combination trials.
The research team draws from institutions in Sydney, including the Asbestos Diseases Research Institute, the University of Sydney, and the University of Technology Sydney, with collaborators from Flinders University and Western Sydney University. The study was led by Yuen Yee Cheng, whose group at the University of Technology Sydney studies the molecular biology of thoracic cancers and uses 3D spheroid and xenograft models to investigate chemoresistance in mesothelioma. The paper is open access.
References
Scientific Reports. (2026-02-11). Validation of chemoresistance phenotypes in pleural mesothelioma across 2D, 3D, and in vivo models.
https://www.nature.com/articles/s41598-026-38692-4
Reader Q&A
Frequently Asked Questions
What is cisplatin-pemetrexed?
Cisplatin combined with pemetrexed is the standard first-line chemotherapy for pleural mesothelioma. The combination was approved by the U.S. FDA in 2004 based on a phase 3 trial showing improved survival over cisplatin alone. It remains a foundation of treatment, often paired with immunotherapy in newer regimens.
Why do 3D models matter for mesothelioma research?
Pleural mesothelioma grows as a sheet of tumor lining the chest cavity, with limited oxygen and complex tissue interactions. Two-dimensional lab cultures grown on plastic dishes do not reproduce those conditions, so drugs that work in 2D often fail in clinical trials. A 3D spheroid model reproduces tumor structure, hypoxia, and cell-to-cell signaling, giving researchers a more accurate test bed for new therapies.
What are PI3K/AKT and Notch signaling?
PI3K/AKT and Notch are signaling pathways that cells use to control growth, survival, and differentiation. Both are frequently activated in cancers and have been linked to resistance against chemotherapy. Several PI3K inhibitors are approved for other cancers, and Notch inhibitors are in clinical development. The Australian team’s findings suggest both pathways may be worth targeting in mesothelioma combination trials.
Could this lead to new mesothelioma treatments?
The study itself does not test new drugs in patients. It is a preclinical platform paper. The next steps for this kind of research would be using the 3D model to screen PI3K/AKT and Notch pathway inhibitors in combination with cisplatin-pemetrexed, then advancing the most promising candidates into early-phase clinical trials. That process typically takes several years.
Will they ever find a cure for asbestos?
No cure exists for mesothelioma, the cancer linked to asbestos exposure, though treatments like immunotherapy combinations have improved survival rates to 79.6% at 1 year for pleural cases with multimodal care and 50% at 5 years for peritoneal cases with HIPEC. Researchers pursue preventive agents such as sulforaphane from cruciferous vegetables for high-risk individuals with BAP1 mutations, funded by the National Cancer Institute, and explore gene therapies, CRISPR, and drugs targeting inflammation or tumor blood supply. Over 80 clinical trials test emerging therapies, with some patients achieving remission or remaining cancer-free, but evidence shows no definitive cure as of 2026. Prevention through avoiding asbestos exposure remains the most effective measure, as legacy asbestos persists in pre-1980s structures.
What famous person died from mesothelioma?
Steve McQueen, a prominent actor known for films like The Great Escape and The Magnificent Seven, died from pleural mesothelioma in 1980 at age 50. His exposure is linked to U.S. Marine service, shipyard work, and possible movie set insulation. Other celebrities who died from mesothelioma include musician Warren Zevon (2003), actor Ed Lauter (2013), and NFL player Merlin Olsen. Paleontologist Stephen Jay Gould survived peritoneal mesothelioma for 20 years before dying from unrelated lung cancer in 2002.
What are the first signs of asbestos poisoning?
The first signs of asbestos exposure, often called asbestos poisoning, typically appear 10 to 50 years after initial contact and include shortness of breath, persistent dry cough, and chest pain or tightness. Other early symptoms may involve fatigue, unexplained weight loss, and crackling sounds in the lungs when breathing. These signs resemble common respiratory conditions, which can delay recognition of asbestos-related diseases like asbestosis or mesothelioma.
How to stop worrying about asbestos?
Asbestos poses a health risk primarily through inhalation of airborne fibers, which occurs when materials are disturbed or damaged. If you suspect asbestos in your home or workplace, having a licensed professional conduct testing can either confirm its absence or identify its location, allowing you to develop a management plan. Undisturbed asbestos-containing materials in good condition generally pose minimal risk, so leaving them intact and well-maintained is often safer than attempting removal. If you believe you have been exposed, limit further exposure, use appropriate respiratory protection if available, and contact a professional for guidance. Learning accurate information about asbestos risks and taking practical control measures can help reduce anxiety by replacing uncertainty with knowledge and action.