Epigenetic priming promotes acquisition of tyrosine kinase inhibitor resistance and oncogene amplification in human lung cancer.

In mammalian cells, gene copy number is tightly controlled to maintain gene expression and genome stability. However, a common molecular feature across cancer types is oncogene amplification, which promotes cancer progression by drastically increasing the copy number and expression of tumor-promoting genes. For example, in tyrosine kinase inhibitor (TKI)-resistant lung adenocarcinoma (LUAD), oncogene amplification occurs in over 40% of patients' tumors.

Tracing the evolution of single-cell cancer 3D genomes: an atlas for cancer gene discovery.

Although three-dimensional (3D) genome structures are altered in cancer cells, little is known about how these changes evolve and diversify during cancer progression. Leveraging genome-wide chromatin tracing to visualize 3D genome folding directly in tissues, we generated 3D genome cancer atlases of murine lung and pancreatic adenocarcinoma. Our data reveal stereotypical, non-monotonic, and stage-specific alterations in 3D genome folding heterogeneity, compaction, and compartmentalization as cancers progress from normal to preinvasive and ultimately to invasive tumors, discovering a potential structural bottleneck in early tumor progression.

Perturb-tracing enables high-content screening of multiscale 3D genome regulators.

Three-dimensional (3D) genome organization becomes altered during development, aging, and disease, but the factors regulating chromatin topology are incompletely understood and currently no technology can efficiently screen for new regulators of multiscale chromatin organization. Here, we developed an image-based high-content screening platform (Perturb-tracing) that combines pooled CRISPR screen, a new cellular barcode readout method (BARC-FISH), and chromatin tracing. We performed a loss-of-function screen in human cells, and visualized alterations to their genome organization from 13,000 imaging target-perturbation combinations, alongside perturbation-paired barcode readout in the same single cells.

Chromatin tracing and multiplexed imaging of nucleome architectures (MINA) and RNAs in single mammalian cells and tissue.

The genome is hierarchically organized into several 3D architectures, including chromatin loops, domains, compartments and regions associated with nuclear lamina and nucleoli. Changes in these architectures have been associated with normal development, aging and a wide range of diseases. Despite its critical importance, understanding how the genome is spatially organized in single cells, how organization varies in different cell types in mammalian tissue and how organization affects gene expression remains a major challenge.

ProbeDealer is a convenient tool for designing probes for highly multiplexed fluorescence in situ hybridization.

Fluorescence in situ hybridization (FISH) is a powerful method to visualize the spatial positions of specific genomic loci and RNA species. Recent technological advances have leveraged FISH to visualize these features in a highly multiplexed manner. Notable examples include chromatin tracing, RNA multiplexed error-robust FISH (MERFISH), multiplexed imaging of nucleome architectures (MINA), and sequential single-molecule RNA FISH.

Multiplexed imaging of nucleome architectures in single cells of mammalian tissue.

The three-dimensional architecture of the genome affects genomic functions. Multiple genome architectures at different length scales, including chromatin loops, domains, compartments, and lamina- and nucleolus-associated regions, have been discovered. However, how these structures are arranged in the same cell and how they are mutually correlated in different cell types in mammalian tissue are largely unknown.