Whole-Body Profiling of Cancer Metastasis with Single-Cell Resolution

Abstract

Stochastic and proliferative events initiated from a single cell can disrupt homeostatic balance and lead to fatal disease processes such as cancer metastasis. To overcome metastasis, it is necessary to detect and quantify sparsely distributed metastatic cells throughout the body at early stages. Here, we demonstrate that clear, unobstructed brain/body imaging cocktails and computational analysis (CUBIC)-based cancer (CUBIC-cancer) analysis with a refractive index (RI)-optimized protocol enables comprehensive cancer cell profiling of the whole body and organs. We applied CUBIC-cancer analysis to 13 mouse models using nine cancer cell lines and spatiotemporal quantification of metastatic cancer progression at single-cell resolution. CUBIC-cancer analysis suggests that the epithelial-mesenchymal transition promotes not only extravasation but also cell survival at metastatic sites. CUBIC-cancer analysis is also applicable to pharmacotherapeutic profiling of anti-tumor drugs. CUBIC-cancer analysis is compatible with in vivo bioluminescence imaging and 2D histology. We suggest that a scalable analytical pipeline with these three modalities may contribute to addressing currently incurable metastatic diseases.

Intracellular and extracellular TGF-β signaling in cancer: some recent topics

“…Indeed, CUBIC-cancer analysis suggests that the TGF-β-induced EMT promotes cell survival at metastatic sites as well as extravasation of cancer cells (Fig. 2) [113]. These technical advances in visualization of EMT in animal models, together with molecular mechanistic studies, advanced bioinformatics, and mathematical modeling, will provide a better understanding of the roles of TGF-β signaling and crosstalk with other signaling pathways in the progression of cancers.…”

“…The development of novel techniques, including intravital imaging, has helped demonstrate the roles of the epithelial plasticity program in cancer. More recently, tissue-clearing based 3D imaging strategies have been applied to cancer models, and these techniques have enabled the visualization of cancer micrometastases throughout the body [112,113]. One of the tissue-clearing protocols, clear unobstructed brain/body imaging cocktails (CUBIC)-based cancer analysis, allowed spatiotemporal visualization and quantification of the metastatic cancer cells at single cell resolution [113].…”

“…More recently, tissue-clearing based 3D imaging strategies have been applied to cancer models, and these techniques have enabled the visualization of cancer micrometastases throughout the body [112,113]. One of the tissue-clearing protocols, clear unobstructed brain/body imaging cocktails (CUBIC)-based cancer analysis, allowed spatiotemporal visualization and quantification of the metastatic cancer cells at single cell resolution [113]. This approach provides tools to visualize EMT at better resolution in mouse models at the whole organ level, and promotes understanding of the dynamics of the EMT program in cancer progression.…”

Recent advances in understanding the complexities of metastasis

“…The development of new approaches to detect and quantify sparsely distributed metastatic cells throughout the body at early stages in in vivo tumour models is underway 56 . However, in the clinical setting, the current tumour staging procedures and even our highest-resolution imaging technologies are not yet sensitive enough to detect micro-metastases or early tumour cell dissemination, the key events in primary tumour progression to metastasis.…”

3‐dimensional visualization of implant‐tissue interface with the polyethylene glycol associated solvent system tissue clearing method

“…17,18 In addition, only very few ground sections could be achieved from a sample, which provided very limited information for the whole tissue. [21][22][23][24][25][26] Hard tissues are opaque because of mismatched refractive index (RI) among various components, including minerals, lipids, pigments and water. [21][22][23][24][25][26] Hard tissues are opaque because of mismatched refractive index (RI) among various components, including minerals, lipids, pigments and water.…”