Flura-seq identifies organ-specific metabolic adaptations during early metastatic colonization
- Memorial Sloan-Kettering Cancer Center, United States
Abstract
Metastasis-initiating cells dynamically adapt to the distinct microenvironments of different organs, but these early adaptations are poorly understood due to the limited sensitivity of in situ transcriptomics. We developed fluorouracil-labeled RNA sequencing (Flura-seq) for in situ analysis with high sensitivity. Flura-seq utilizes cytosine deaminase (CD) to convert fluorocytosine to fluorouracil, metabolically labeling nascent RNA in rare cell populations in situ for purification and sequencing. Flura-seq revealed hundreds of unique, dynamic organ-specific gene signatures depending on the microenvironment in mouse xenograft breast cancer micrometastases. Specifically, the mitochondrial electron transport Complex I, oxidative stress and counteracting antioxidant programs were induced in pulmonary micrometastases, compared to mammary tumors or brain micrometastases. We confirmed lung metastasis-specific increase in oxidative stress and upregulation of antioxidants in clinical samples, thus validating Flura-seq's utility in identifying clinically actionable microenvironmental adaptations in early metastasis. The sensitivity, robustness and economy of Flura-seq are broadly applicable beyond cancer research.
Data availability
Sequencing data have been deposited in GEO under accession codes GSE93605 and GSE118937.
-
Organ-specific in situ transcriptomics of MDA231 cells identified by Flura-seqNCBI Gene Expression Omnibus, GSE118937.
-
Flura-seq of TGFB treated MDA231 cellsNCBI Gene Expression Omnibus, GSE93605.
-
Integrated RNA and DNA sequencing reveals early drivers of metastatic breast cancerNCBI Gene Expression Omnibus, GSE110590.
-
ubpopulations of MDA-MB-231 and Primary Breast CancersNCBI Gene Expression Omnibus, GSE2603.
-
Breast cancer relapse free survival and lung metastasis free survivalNCBI Gene Expression Omnibus, GSE5327.
-
Breast cancer relapse free survivalNCBI Gene Expression Omnibus, GSE2034.
-
Expression data from primary breast tumorsNCBI Gene Expression Omnibus, GSE12276.
Article and author information
Author details
Funding
National Institutes of Health (P01-CA094060)
- Joan Massagué
Damon Runyon Cancer Research Foundation (DR-12998)
- Harihar Basnet
Department of Defense (W81XWH-12-0074)
- Joan Massagué
National Institutes of Health (T32-CA009207)
- Karuna Ganesh
National Institutes of Health (T32-GM07739)
- Yun-Han Huang
National Institutes of Health (K08-CA230213)
- Karuna Ganesh
National Institutes of Health (F30-CA203238)
- Yun-Han Huang
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: Mouse experiments were performed following the protocols approved by the MSKCC Institutional Animal Care and Use Committee (IACUC) (#99-09-032).
Copyright
© 2019, Basnet et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 6,025
- views
-
- 850
- downloads
-
- 57
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Flura-seq identifies organ-specific metabolic adaptations during early metastatic colonization
eLife 8:e43627.
https://doi.org/10.7554/eLife.43627
Further reading
-
- Cancer Biology
Most human pancreatic ductal adenocarcinoma (PDAC) are not infiltrated with cytotoxic T cells and are highly resistant to immunotherapy. Over 90% of PDAC have oncogenic KRAS mutations, and phosphoinositide 3-kinases (PI3Ks) are direct effectors of KRAS. Our previous study demonstrated that ablation of Pik3ca in KPC (KrasG12D; Trp53R172H; Pdx1-Cre) pancreatic cancer cells induced host T cells to infiltrate and completely eliminate the tumors in a syngeneic orthotopic implantation mouse model. Now, we show that implantation of Pik3ca−/− KPC (named αKO) cancer cells induces clonal enrichment of cytotoxic T cells infiltrating the pancreatic tumors. To identify potential molecules that can regulate the activity of these anti-tumor T cells, we conducted an in vivo genome-wide gene-deletion screen using αKO cells implanted in the mouse pancreas. The result shows that deletion of propionyl-CoA carboxylase subunit B gene (Pccb) in αKO cells (named p-αKO) leads to immune evasion, tumor progression, and death of host mice. Surprisingly, p-αKO tumors are still infiltrated with clonally enriched CD8+ T cells but they are inactive against tumor cells. However, blockade of PD-L1/PD1 interaction reactivated these clonally enriched T cells infiltrating p-αKO tumors, leading to slower tumor progression and improve survival of host mice. These results indicate that Pccb can modulate the activity of cytotoxic T cells infiltrating some pancreatic cancers and this understanding may lead to improvement in immunotherapy for this difficult-to-treat cancer.
-
- Cancer Biology
- Immunology and Inflammation
In this study, we present a proof-of-concept classical vaccination experiment that validates the in silico identification of tumor neoantigens (TNAs) using a machine learning-based platform called NAP-CNB. Unlike other TNA predictors, NAP-CNB leverages RNA-seq data to consider the relative expression of neoantigens in tumors. Our experiments show the efficacy of NAP-CNB. Predicted TNAs elicited potent antitumor responses in mice following classical vaccination protocols. Notably, optimal antitumor activity was observed when targeting the antigen with higher expression in the tumor, which was not the most immunogenic. Additionally, the vaccination combining different neoantigens resulted in vastly improved responses compared to each one individually, showing the worth of multiantigen-based approaches. These findings validate NAP-CNB as an innovative TNA identification platform and make a substantial contribution to advancing the next generation of personalized immunotherapies.
