Biology subjects

Borriello, L.

Publications and source records attributed to Borriello, L..

3 recordsLinked to original sources

bioRxiv2022

Spatiotemporal coordination of stem cell behavior following alveolar injury

Tissue repair requires a highly coordinated cellular response to injury. In the lung, alveolar type 2 (AT2) cells act as stem cells and can replace both themselves and alveolar type 1 cells (AT1); however, the complex orchestration of AT2 stem cell activity following lung injury is poorly understood owing to the inability of tracking individual stem cells and their dynamic behavior over time. Here, we apply live time lapse imaging to ex vivo mouse precision cut lung slice (PCLS) culture and in vivo mouse lung to track individual GFP-labeled AT2 cells following induction of alveolar injury by bleomycin. We observe highly dynamic movement of AT2 cells, including migration within and between alveoli. To map the dynamic evolution of AT2 cell behavior, we introduce Live Cell Encoder (LCE-PHATE), a novel method for converting static snapshots from time lapse imaging into single points representative of entire, dynamic cellular trajectories. Applying LCE-PHATE, we observe the emergence of at least three distinct morphokinetic AT2 cell states associated with AT2 stem cell injury response. Finally, small molecule-based inhibition of Rho-associated protein kinase (ROCK) pathway significantly reduced motility of AT2 stem cells following injury and reduced expression of Krt8, a marker of intermediate progenitor cells. Together, our results uncover motility of alveolar stem cells as a new injury response mechanism in the lung and reveal properties of stem cell motility at high cellular resolution.

cell biology↗

bioRxiv2021

Primary tumor associated macrophages activate programs of invasion and dormancy in disseminating tumor cells.

Metastases are initiated by disseminated tumor cells (DTCs) that depart from the primary tumor and colonize target organs. Growing evidence suggests that the microenvironment of the primary tumor lesion primes DTCs to display dormant or proliferative fates in target organs. However, the manner in which events taking place in the primary tumor influence DTC fate, sometimes long after dissemination, remains poorly understood. With the advent of a novel intravital imaging technique called the Window for High-Resolution Intravital Imaging of the Lung (WHRIL), we have, for the first time, been able to study the live lung longitudinally and follow the fate of individual DTCs that spontaneously disseminate from orthotopic breast tumors. We find, across several models, a high rate of success for tumor cells to complete the initial steps of the metastatic cascade in the secondary site, including retention of DTCs in the lung vasculature, speed of extravasation, and survival after extravasation. Importantly, initiation of metastatic growth was controlled primarily by a rate-limiting step that occurred post-extravasation and at the stage of the conversion of single DTCs from a dormant to a proliferative state. Detailed analysis of these events revealed that, even before dissemination, a subset of macrophages within the primary tumor induces, in tumor cells that are about to disseminate, the expression of proteins that regulate a pro- dissemination (MenaINV) and pro-dormancy (NR2F1) phenotype. Surprisingly, if cancer cells are intravenously injected, the rate limiting stages of MenaINV-associated extravasation, dormancy, and other parameters, are lost or altered in a way that impacts how DTCs progress through the metastatic cascade. Our work provides novel insight into how specific primary tumor microenvironments prime a subpopulation of cells for dissemination and dormancy. We also propose that dissecting mechanisms of metastasis, or testing anti-metastatic therapies, may yield results of limited application if derived from models that do not follow spontaneous dissemination. SIGNIFICANCEThis study provides important insight into the contribution of primary tumor microenvironmental niches to cancer metastasis by identifying the manner in which these niches spawn subpopulations of DTCs that are primed for dissemination and dormancy in the secondary site. This study may provide novel targets that could be inhibited to prevent successful colonization of the secondary site and, hence, metastasis.

cancer biology↗

bioRxiv2020

Live imaging of breast tumors shows macrophage-dependent induction and TMEM-mediated enrichment of cancer stem cells during metastatic dissemination

Cancer stem cells (CSCs) play an important role during metastasis, but the dynamic behavior and induction mechanisms of CSCs are not well understood. We employed high-resolution intravital microscopy using a CSC biosensor to directly observe CSCs in live mice with mammary tumors. CSCs display the slow-migratory, invadopod-rich phenotype that is the hallmark of disseminating tumor cells. CSCs are enriched near macrophages, particularly near macrophage-containing intravasation sites called Tumor Microenvironment of Metastasis (TMEM) doorways. A dramatic enrichment of CSCs occurs on association with TMEM doorways, contributing to the finding that CSCs represent [~]>60% of circulating tumor cells. Mechanistically, stemness is induced in non-stem cancer cells upon their direct contact with macrophages via Notch signaling. In breast cancers from patients, the density of TMEM doorways correlates strongly with the proportion of cancer cells expressing stem cell markers, indicating that in human breast cancer TMEM doorways are not only cancer cell intravasation portals but also CSC programming sites. One Sentence SummaryIntravital imaging reveals macrophage-mediated induction of cancer stem cells in vivo and their dramatic enrichment on dissemination through TMEM doorways.

cancer biology↗