The research team focused on a well-established mouse model of lung adenocarcinoma driven by mutations in the Kras and Trp53 genes, a system that closely recapitulates the progression of human non-small-cell lung cancer. In this model, known as KP-Tracer, cancer cells carry heritable molecular barcodes that accumulate edits as cells divide, allowing researchers to reconstruct family trees of tumor cells long after the fact. By reading out these barcodes alongside genome-wide gene expression, the team could infer not only which cells were related to one another but also where they sat within the tumor and what molecular programs they were running.

Technically, the platform integrates two complementary spatial assays. Slide-seq provides genome-wide expression measurements on dense arrays of bead-based spots at near-cellular resolution across entire tissue sections, while Slide-tags assigns spatial coordinates to individual cell nuclei, enabling single-cell profiling with positional information. The lineage barcodes embedded in the tumor cells could be captured in both assays, though with substantial dropout and missing data. To address this, the team developed computational methods, including spatial imputation strategies that borrow lineage information from neighboring spots, and benchmarked their phylogeny-reconstruction pipelines extensively on simulated data to ensure that the inferred evolutionary trees were robust to the noise inherent in spatial measurements.

With this integrated platform in hand, the researchers asked a fundamental question: where within a tumor does expansion actually happen, and what does the microenvironment look like in those regions? By combining the reconstructed phylogenies with spatial maps, an approach the authors describe as tumor phylogeography, they identified regions of recent subclonal expansion, essentially the growing edges of the tumor’s family tree. These expanding subclones were not randomly distributed. Instead, they were consistently associated with a distinctive microenvironmental signature: hypoxia, fibrosis and immunosuppression.

The association was striking. Areas harboring rapidly expanding subclones were enriched for low-oxygen conditions, marked by expression of hypoxia-response genes such as the glucose transporter GLUT1. They also contained dense deposits of extracellular matrix produced by activated fibroblasts and were populated by immunosuppressive immune cells, including Arg1-expressing tumor-associated macrophages. In other words, the most successful cancer clones were not simply the ones with the best intrinsic growth programs; they were the ones that had managed to engineer, or at least exploit, a microenvironment that suppressed immune attack and supplied the conditions for aggressive proliferation.

To disentangle cause from correlation, the team turned to controlled experiments. Using organoid co-culture systems, they exposed cancer cells to hypoxic conditions and to specific stromal cell partners, testing how these extrinsic factors influenced cancer cell state. The results supported a model in which hypoxia and intercellular signaling integrate to push cancer cells toward prometastatic, high-plasticity states, including epithelial-to-mesenchymal transition-like programs previously linked to metastatic competence. Spatially aware ligand-receptor analysis, performed with a purpose-built algorithm called LARIS, further revealed that the rewired interactions between macrophages, fibroblasts and cancer cells in expanding niches differed markedly from those in non-expanding regions, pinpointing candidate signaling pathways that sustain the aggressive state.

Perhaps the most consequential findings concern metastasis. By tracing lineage barcodes from primary tumors into metastatic lesions found in lymph nodes, the diaphragm and other sites, the researchers showed that metastases arise from spatially confined subclones within the primary tumor rather than from cells scattered broadly across it. The metastasis-seeding subclones occupied identifiable niches at the primary site, and their genealogical signatures could be detected across serial tissue sections, effectively allowing the team to watch the metastatic cascade unfold backward from the established lesion to its birthplace in the primary tumor.

Equally important, the study found that metastases do not merely inherit traits from their parent clones; they actively remodel the distant sites they colonize. Metastatic lesions, and even the pre-metastatic neighborhoods surrounding them, became fibrotic and collagen-rich, with elevated TGF-beta signaling. The team extended this observation to human disease by analyzing single-cell data from a pan-cancer atlas of human brain metastases and spatial transcriptomics datasets of human non-small-cell lung cancer, finding that collagen deposition, TGF-beta activity and hypoxia signatures were similarly elevated in human metastatic compartments. This convergence between the mouse model and human data strengthens the case that the mechanisms uncovered are not artifacts of the experimental system.

The implications for cancer medicine are substantial. If prometastatic cell states emerge specifically within hypoxic, fibrotic and immunosuppressive niches, then targeting the microenvironment, for example by alleviating hypoxia, modulating fibroblast activity or reprogramming suppressive macrophages, could potentially prevent the emergence of metastatic competence before it arises. The findings also suggest that sampling strategies in the clinic, which often rely on a single biopsy, may miss the spatially restricted subclones that matter most for a patient’s prognosis. Understanding where within a tumor the dangerous clones reside could inform how biopsies are taken and how risk is assessed.

The study also represents a methodological milestone for the field of spatial lineage tracing. The authors have released their processed data via Zenodo, deposited raw sequencing data under a public BioProject accession, and made their analysis code, including the Cassiopeia lineage-reconstruction framework and spatial analysis notebooks, freely available on GitHub under an open license. As these tools proliferate, the ability to read a tumor’s history directly from its architecture may become a standard part of the cancer biologist’s toolkit, transforming how researchers study not only lung cancer but the evolutionary dynamics of malignancies throughout the body.

Subject of Research: Spatiotemporal lineage tracing of lung adenocarcinoma to map tumor growth, microenvironmental remodeling and metastasis

Article Title: Spatiotemporal lineage tracing reveals the dynamic spatial architecture of tumor growth and metastasis

Article References: Jones, M. G., Sun, D., Min, K. H. J., Colgan, W. N., Wang, H., Török, T., Ribeiro, J., Xue, J., Cardoso, E. C., Rong, Y., Tian, L., Weir, J. A., Chen, V. Z., Koblan, L. W., Yost, K. E., Mathey-Andrews, N., D’Souza, E., Russell, A. J. C., Stickels, R. R., … Yang, D. (2026). Spatiotemporal lineage tracing reveals the dynamic spatial architecture of tumor growth and metastasis. Nature Genetics, 58(9), 2398-2410. https://doi.org/10.1038/s41588-026-02739-z

Image Credits: AI Generated

DOI: 10.1038/s41588-026-02739-z

Keywords: lineage tracing, spatial transcriptomics, tumor evolution, lung adenocarcinoma, tumor microenvironment, metastasis, hypoxia, fibrosis, immunosuppression, tumor phylogeography, Slide-seq, Slide-tags

The research team, led by investigators at the First Affiliated Hospital of Xinjiang Medical University, combined single-cell RNA sequencing, spatial transcriptomics, CRISPR-based gene editing, pharmacological pathway modulation, and xenograft modeling to trace SOX9’s role across both time and tissue space. Using a publicly available single-cell dataset, they reconstructed a pseudotime trajectory with Monocle3, mapping the continuous transition from astrocytes to malignant glioma cells. The analysis revealed substantial cellular heterogeneity within glioma samples, encompassing malignant cells alongside astrocytes, macrophages, T cells, B cells, monocytes, neurons, fibroblasts, and endothelial cells.

The most consequential finding to emerge from the trajectory analysis was SOX9’s temporal behavior. Its expression was concentrated almost exclusively in astrocyte and malignant cell populations, and along the inferred developmental arc it peaked early and then declined steadily as cells matured into malignant states. Correlation analysis confirmed this downward trend, with Pearson and Spearman coefficients both strongly negative and highly significant. At the level of trajectory nodes, SOX9 dominated the early, astrocyte-rich segments and faded in the terminal malignant zones, a pattern inconsistent with the conventional view of SOX9 as a constitutively active stemness factor.

To probe what SOX9 might be doing during that early window, the researchers scored the activity of the Hippo pathway, a master regulator of organ size and stem cell fate whose downstream effectors YAP and TAZ are established drivers of glioblastoma plasticity. Using Gene Set Variation Analysis, they quantified an upstream kinase module, including MST1/2, LATS1/2, SAV1, MOB1A/B, NF2, and WWC1, and a canonical YAP/TAZ target module containing genes such as CTGF, CYR61, ANKRD1, AXL, and BIRC5. Both modules showed inverse relationships with SOX9 expression, and generalized additive modeling revealed that pseudotime and SOX9 each contributed independent, nonlinear effects on pathway activity. In other words, the SOX9–Hippo relationship was phase-dependent, strongest during early-to-intermediate stages of the transition and not a simple monotonic association.

Spatial transcriptomics added a second, geographic dimension to the story. Analyzing four anatomically distinct regions of glioblastoma tissue—the tumor–normal interface, the pure tumor core, the perivascular compartment, and the tumor–necrosis interface—the team mapped SOX9 expression against the probability that each spatial spot contained malignant cells. The coupling between SOX9 and malignancy was weak or unstable at the tumor edges and the necrotic margin, modest in the tumor core, and most robust in the perivascular niche. There, SOX9 expression was markedly elevated, correlations with malignant cell probability were strongest, and neighborhood enrichment and spatial autocorrelation statistics all confirmed significant co-localization.

This regional specificity is biologically meaningful. The perivascular niche has long been recognized as a reservoir for stem-like glioblastoma cells, bathed in vascular, hypoxic, and paracrine signals that nurture cellular plasticity. The findings suggest that SOX9-dependent reprogramming is not only time-restricted but niche-conditioned, with perivascular regions providing the most permissive anatomical context for effective SOX9–Hippo–YAP/TAZ coupling. Elsewhere in the tumor, downstream malignant programs may be sustained through alternative inputs, weakening the spatial coherence of the axis.

Functional experiments brought the correlation studies into the laboratory. Using lentiviral vectors, the team generated U87 glioma cells stably overexpressing SOX9 and used CRISPR/Cas9 to knock out the gene in U251 cells, validating the edits by Sanger sequencing and confirming a frameshift-inducing deletion in the knockout clone. SOX9 overexpression modestly increased proliferation, migration, and invasion while reducing apoptosis, whereas SOX9 knockout produced the opposite phenotype across wound-healing, Transwell invasion, and flow-cytometric apoptosis assays. Critically, treatment with XMU-MP-1, an inhibitor of the upstream Hippo kinases MST1/2, partially rescued the defects caused by SOX9 loss, linking SOX9 function experimentally to Hippo pathway state.

Phosphorylation-level Western blotting sharpened the mechanistic picture. SOX9 overexpression raised the ratio of phosphorylated to total YAP and lowered the phosphorylated-to-total MOB1 ratio, while SOX9 knockout produced the reciprocal pattern. XMU-MP-1 shifted both readouts toward the SOX9-overexpression signature, and total MOB1 remained unchanged across groups, indicating that the pathway rewiring was phosphorylation-dependent rather than a simple change in protein abundance. YAP and TAZ mRNA and protein levels rose with SOX9 gain and fell with SOX9 loss, and drug treatment partially restored them in SOX9-deficient cells, extending the transcriptomic associations to protein-level pathway readouts.

In vivo, the story held. Subcutaneous xenografts in nude mice showed that SOX9 overexpression significantly accelerated U87-derived tumor growth from day 14 onward, while SOX9 knockout markedly suppressed U251-derived tumors. XMU-MP-1 treatment further enlarged SOX9-overexpressing tumors and partially reversed the growth inhibition caused by SOX9 loss. Histopathology mirrored these dynamics: SOX9-overexpressing tumors displayed increased necrosis and nuclear atypia, whereas knockout tumors showed milder pathology, and the drug partially reversed both patterns. Ki67 immunohistochemistry confirmed the corresponding changes in proliferative activity, and CD68 staining revealed that myeloid and macrophage-like cell accumulation also shifted with SOX9 status, adding an immune dimension to the tumor microenvironmental effects.

Taken together, the study proposes what the authors call an early priming–late decoupling model. SOX9 acts early, at the moment of astrocyte-to-malignant conversion, to initiate Hippo–YAP/TAZ-linked malignant reprogramming. Once downstream transcriptional networks consolidate, the tumor becomes progressively less dependent on sustained SOX9 expression, which explains why stemness programs can persist in advanced disease even as SOX9 levels fall. The translational implication is pointed: therapies aimed at SOX9 may work best before malignant programs fully consolidate, whereas in later-stage tumors, blocking SOX9 alone may prove insufficient. The results argue for stage-specific and niche-aware strategies targeting the SOX9/Hippo/YAP–TAZ axis, particularly in the perivascular compartment where the axis is most strongly engaged. Limitations remain, including the reliance on public cohorts of limited size, established cell lines, and subcutaneous rather than orthotopic models, and the absence of YAP/TAZ nuclear localization data or a second pathway inhibitor. Even so, the study repositions SOX9 from a static stemness marker to a dynamic state-switch regulator, and it provides a conceptual framework for timing future interventions against one of medicine’s most stubborn cancers.

Subject of Research: The temporal role of SOX9 in priming Hippo–YAP/TAZ signaling during glioblastoma stemness acquisition

Article Title: Early SOX9 Activation Primes Hippo–YAP/TAZ Rewiring During Glioblastoma Stemness Acquisition

Article References: Early SOX9 Activation Primes Hippo–YAP/TAZ Rewiring During Glioblastoma Stemness Acquisition. (n.d.). https://doi.org/10.1111/jcmm.71341

Image Credits: AI Generated

DOI: 10.1111/jcmm.71341

Keywords: glioblastoma, SOX9, Hippo pathway, YAP/TAZ, glioma stem cells, pseudotime analysis, spatial transcriptomics, perivascular niche, XMU-MP-1, CRISPR, tumor plasticity, xenograft