Despite decades of study, there are still many unanswered questions about metastasis, the process by which a localized cancer becomes a systemic disease. One of these questions is the nature of the tumor cells that give rise to metastases. Although conventional models suggest that metastases are seeded by single cells from the primary tumor, there is growing evidence that seeding requires the collective action of tumor cells traveling together in clusters. Here, we review this evidence, which comes from analysis of both experimental models and patient samples. We present a model of metastatic dissemination that highlights the activities of clusters of tumor cells that retain and require their epithelial properties.
Invasion into surrounding tissues is the first step of metastasis, and an understanding of the molecular basis of the invasive process may suggest novel strategies for anti-metastatic therapy. Breast tumors typically invade as adherent groups of cells, a process known as collective invasion. In vivo, collective invasion occurs within a complex tissue environment and involves interactions among the cancer cells, stromal cells, and the extracellular matrix (ECM). An additional challenge to understanding cancer invasion is that primary breast tumors contain diverse cancer cells with varied molecular phenotypes. It is difficult to determine the relative contribution of these subpopulations to invasion from analysis of histologic sections.
We sought to reduce this complexity and to identify the most invasive cancer cells in the primary tumor in an unbiased fashion [1]. To accomplish this goal, we developed a three dimensional (3D) organoid invasion assay (Figure (Figure1A).1A). Briefly, we use enzymes and mechanical disruption to isolate organoids from primary breast tumors from mouse models and human patients. Each organoid is composed of several hundred cancer cells and is embedded in an invasion promoting ECM [2] (collagen I). Tumor organoids invade collectively and the cells at the tips of invasion strands are protrusive and highly interactive with the ECM. We refer to the cells at the tips of these strands as invasive leader cells (Figure (Figure1B1B).
Figure 1
A. Tumor organoids are isolated from fresh primary tumors through a combination of mechanical disruption and enzymatic digestion. Tumor organoids are then embedded in 3D collagen I and become invasive. B. Organoids extend multiple invasive strands into ...
We found that the molecular phenotype of invasive leader cells was distinct from the bulk tumor cells and conserved across breast cancer subtypes [1]. Leader cells expressed markers of basal epithelium, which are the cells in normal stratified tissues that interact with the ECM (Figure (Figure1C).1C). The basal cytokeratin, keratin-14 (K14), was expressed in ~90% of leader cells. Importantly, K14+ cells led collective invasion in multiple distinct mouse models and in diverse primary human breast tumors. We next used molecular biosensors to demonstrate that K14+ invasive leader cells were generated from non-invasive K14- bulk tumor cells. Importantly, knockdown of either K14 or p63, another leader cell marker, was sufficient to inhibit collective invasion.
Our data establish three important concepts. First, we have demonstrated that the invasive behavior of the primary tumor is determined by a subset of specialized cancer cells1. Second, our data suggest a common molecular biology underlying breast cancer metastasis, because K14+ cells led collective invasion in 3D organoid invasion assays from patients with different breast cancer subtypes. In support of this concept, multiple groups have observed that K14 expression in breast tumors correlates with poor patient outcomes, independent of breast cancer subtype [3-5]. Third, since bulk tumor cells can convert into K14+ invasive leaders, we hypothesize that inhibition of the basal molecular program could control progression in patients with metastatic disease.
Our 3D organoid invasion assay can also be utilized to identify invasive leader cells in other epithelial cancers. Because basal cells are found in many stratified epithelial tissues, the basal invasive program we identified may be utilized across diverse cancers. In support of this concept, basal cytokeratins are associated with invasion in both lung adenocarcinoma and hepatocellular carcinoma [6,7].
It is now critical to develop the translational framework to leverage our knowledge of invasive leader cells to improve patient outcomes. We are specifically interested to determine whether the abundance of invasive leader cells in the primary tumor will provide independent information about the prognosis of individual patients. Our invasion assays also provide an ideal platform to identify anti-invasive therapeutic compounds. Now that we have the invasive leader cell in our sights, we are working to defeat this new adversary.
This article has been corrected. The original version (PDF) is appended to this article as a Supplement.Few randomized trials have evaluated the effect of reducing red meat intake on clinically important outcomes.To summarize the effect of lower versus higher red meat intake on the incidence of cardiometabolic and cancer outcomes in adults.EMBASE, CENTRAL, CINAHL, Web of Science, and ProQuest from inception to July 2018 and MEDLINE from inception to April 2019, without language restrictions.Randomized trials (published in any language) comparing diets lower in red meat with diets higher in red meat that differed by a gradient of at least 1 serving per week for 6 months or more.Teams of 2 reviewers independently extracted data and assessed the risk of bias and the certainty of the evidence.Of 12 eligible trials, a single trial enrolling 48 835 women provided the most credible, though still low-certainty, evidence that diets lower in red meat may have little or no effect on all-cause mortality (hazard ratio [HR], 0.99 [95% CI, 0.95 to 1.03]), cardiovascular mortality (HR, 0.98 [CI, 0.91 to 1.06]), and cardiovascular disease (HR, 0.99 [CI, 0.94 to 1.05]). That trial also provided low- to very-low-certainty evidence that diets lower in red meat may have little or no effect on total cancer mortality (HR, 0.95 [CI, 0.89 to 1.01]) and the incidence of cancer, including colorectal cancer (HR, 1.04 [CI, 0.90 to 1.20]) and breast cancer (HR, 0.97 [0.90 to 1.04]).There were few trials, most addressing only surrogate outcomes, with heterogeneous comparators and small gradients in red meat consumption between lower versus higher intake groups.Low- to very-low-certainty evidence suggests that diets restricted in red meat may have little or no effect on major cardiometabolic outcomes and cancer mortality and incidence.None (PROSPERO: CRD42017074074).
This article has been corrected. The original version (PDF) is appended to this article as a Supplement. Background: Dietary guidelines generally recommend limiting intake of red and processed meat. However, the quality of evidence implicating red and processed meat in adverse health outcomes remains unclear. Purpose: To evaluate the association between red and processed meat consumption and all-cause mortality, cardiometabolic outcomes, quality of life, and satisfaction with diet among adults. Data Sources: EMBASE (Elsevier), Cochrane Central Register of Controlled Trials (Wiley), Web of Science (Clarivate Analytics), CINAHL (EBSCO), and ProQuest from inception until July 2018 and MEDLINE from inception until April 2019, without language restrictions, as well as bibliographies of relevant articles. Study Selection: Cohort studies with at least 1000 participants that reported an association between unprocessed red or processed meat intake and outcomes of interest. Data Extraction: Teams of 2 reviewers independently extracted data and assessed risk of bias. One investigator assessed certainty of evidence, and the senior investigator confirmed the assessments. Data Synthesis: Of 61 articles reporting on 55 cohorts with more than 4 million participants, none addressed quality of life or satisfaction with diet. Low-certainty evidence was found that a reduction in unprocessed red meat intake of 3 servings per week is associated with a very small reduction in risk for cardiovascular mortality, stroke, myocardial infarction (MI), and type 2 diabetes. Likewise, low-certainty evidence was found that a reduction in processed meat intake of 3 servings per week is associated with a very small decrease in risk for all-cause mortality, cardiovascular mortality, stroke, MI, and type 2 diabetes. Limitation: Inadequate adjustment for known confounders, residual confounding due to observational design, and recall bias associated with dietary measurement. Conclusion: The magnitude of association between red and processed meat consumption and all-cause mortality and adverse cardiometabolic outcomes is very small, and the evidence is of low certainty. Primary Funding Source: None. (PROSPERO: CRD42017074074)
Summary This metadata record provides details of the data supporting the claims of the related manuscript: “Dynamic Contrast-Enhanced Breast MRI Features Correlate with Invasive Breast Cancer Angiogenesis”. The related study evaluated the association of semi-quantitative kinetic and radiomic breast cancer features on dynamic contrast enhanced (DCE)-MRI with microvessel density (MVD), a marker for angiogenesis, as angiogenesis is a critical component of breast cancer development, and identification of imaging-based angiogenesis assays has prognostic and treatment implications. Type of data: dynamic contrast enhanced magnetic resonance imaging (DCE-MRI), tabular metadata Subject of data: Homo sapiens, microvessel density (MVD) Sample size: 27 Recruitment: Patients over the age of 18 were prospectively recruited for the study if they had a new diagnosis of stage I - III invasive breast cancer with a minimum lesion size of 1.5 cm identified on core needle biopsy and underwent a clinical breast MRI at SCCA to evaluate the extent of disease. Data access The de-identified DCE-MRI data, measures and metadata are shared openly in the file 'Xiao_MVD_Data_npjBreastCancer_repository.xlsx', which is attached with this data record.The pathology CD-31 stained slides data are not publicly available for the following reason: no digitised versions of the slides have been created. Corresponding author(s) for this study Savannah C. Partridge, PhD, Department of Radiology, University of Washington, Seattle, WA. Email: scp3@u.washington.edu Study approval This prospective study was approved by the Institutional Review Board of the Fred Hutchinson Cancer Research Center (IR#8148) and was compliant with the Health Insurance Portability and Accountability Act. All patients provided informed consent and were enrolled at the University of Washington/Seattle Cancer Care Alliance (SCCA) between January 2016 and July 2017.
Abstract Tumors are multicellular ecosystems that communicate through the exchange of extracellular signaling molecules. In breast cancer, this multicellular communication can enable tumor cells to cooperate in a range of contexts, including tumor invasion and the outgrowth of distal metastases. Illuminating the mechanisms by which tumor cells communicate may reveal new therapies. To this end, three-dimensional tumor organoid models have emerged as versatile platforms for modeling multicellular behavior ex vivo. However, organoid culture typically requires the use of poorly defined, animal-derived extracellular matrices, such as Matrigel. These exogenous matrices contain thousands of proteins that dominate over and conceal cell-secreted factors in conventional proteomics approaches. Revealing low abundance cell-secreted factors from this complex exogenous background presents a formidable challenge. To surmount this challenge, we develop a new method to isolate the pericellular proteome in 3D organotypic culture models. This technology harnesses biorthogonal click chemistry to bypass exogenous factors, infiltrate intercellular spaces, and retrieve the endogenous intercellular proteome. This approach requires no genetic manipulation, requires only 1 million cells, and can be adapted to diverse organotypic models. These capabilities enable isolation of intercellular signaling factors in models that yield precious amounts of material and that can sustain only limited manipulation ex vivo, which we demonstrate using organoids established from patient-derived xenografts. To establish the generalizability of our approach, we apply this technology to a panel of breast cancer and small-cell lung cancer organoid models. Furthermore, we demonstrate that this method can be readily adapted to different extracellular matrix environments that are widely employed in organoid research, including basement membrane matrices and collagen gels. Taken together, our results establish this technology as a scalable and generalizable platform that may open opportunities for researchers investigating diverse questions in organoid models of cancer. Moving forward, we are leveraging these capabilities to investigate changes in the intercellular proteome that emerge after the acquisition of therapy resistance. We hope to uncover new mechanisms of collective signaling that may be targeted to overcome therapy resistance. Citation Format: Brad A. Krajina, Ami Yamamoto, Kevin J. Cheung, Samuel Madasu. Interrogating multicellular signaling in breast cancer using a bio-orthogonal chemistry-based proteomics platform [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-23-19.
Resume Objectif Passer en revue la prise en charge initiale des blessures traumatiques communes a la main que voient les medecins de soins primaires. Sources des donnees Nous avons examine les donnees cliniques probantes et les ouvrages specialises recents cernes par des recherches dans la base de donnees electronique MEDLINE. Nous avons utilise l’opinion d’experts pour completer les recommandations dans les domaines ou les donnees scientifiques etaient rares. Message principal Les medecins de soins primaires sont couramment appeles a prendre en charge des patients victimes de blessures traumatiques a la main. Dans le contexte d’un cas clinique, nous examinons l’evaluation, le diagnostic et la prise en charge initiale des traumatismes communs a la main. La presentation et la prise en charge des blessures au lit de l’ongle, des amputations de l’extremite du doigt, des doigts en maillet, des fractures a la main, des lacerations de tendons, des morsures et de la tenosynovite infectieuse seront aussi discutees. Les principes de la prise en charge des blessures traumatiques a la main comportent la reduction et l’immobilisation des fractures, la prescription d’imagerie radiographique post-reduction, l’obtention d’un recouvrement par les tissus mous, la prevention et le traitement des infections et l’assurance d’une prophylaxie antitetanique. Conclusion Il est essentiel d’assurer une evaluation et une prise en charge appropriees des blessures traumatiques a la main pour prevenir une morbidite considerable a long terme dans une population autrement en sante. La reconnaissance sans delai des blessures qui necessitent une demande de consultation urgente ou rapide aupres d’un chirurgien specialiste de la main est egalement critique.
Abstract An early step in breast cancer progression is invasion of tumor cells into surrounding tissues. In many breast cancers, particularly ductal carcinomas, this invasion is accomplished by tumor cells migrating as a cohesive group. This often involves cells that take on heterogeneous roles as either leader or follower cells. While studies in common mouse and human breast cancer models have established that leader cells express high levels of keratin-14 (K14) and other basal epithelial markers, the molecular mechanisms regulating K14+ leader cell identity remain obscure. Here we performed time-sampled single cell RNA-sequencing in 3D type I collagen-embedded tumor organoids isolated from the MMTV-PyMT luminal B model of breast cancer. 11 distinct cellular transcriptional states were identified and correlated with K14 expression and invasive strand formation. Having identified the leader cell state we next asked what transcription factors were enriched, reasoning that transcription factors could be master regulators of leader cell fate. 30 different shRNAs targeting 10 genes were systematically evaluated for their effects on collective invasion. From this screen, suppression of Hes1, the downstream target of Notch signaling, yielded a marked switch from collective to single cell invasion. Disseminating single tumor cells maintained high expression of K14 in Hes1 knockdown organoids which was phenocopied by gamma-secretase inhibition in a human TNBC PDX model. Because K14+ tumor cells highly express the Notch ligand Jag1, these results support a model in which Notch signaling, specifically through activation of Hes1, dictates leader cell identity and spatial organization during collective invasion. Studies are ongoing investigating the impact of Hes1 dynamics on leader cell adhesion, hybrid EMT state, and preference for single versus collective metastasis. Because Notch suppression induces leader cell dissemination, we propose that Notch targeted therapy should be combined with therapies eradicating leader cells. Citation Format: Andrea E. Doak, Kevin J. Cheung. Regulation of cellular identity and spatial organization during collective breast cancer invasion. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-14-05.