Investigate Cancer Metastasis Research Articles

Understanding organotropism in cancer metastasis using microphysiological systems.

Cancer metastasis, the leading cause of cancer-related deaths, remains a complex challenge in medical science. Stephen Paget's "seed and soil theory" introduced the concept of organotropism, suggesting that metastatic success depends on specific organ microenvironments. Understanding organotropism not only offers potential for curbing metastasis but also novel treatment strategies. Microphysiological systems (MPS), especially organ-on-a-chip models, have emerged as transformative tools in this quest. These systems, blending microfluidics, biology, and engineering, grant precise control over cell interactions within organ-specific microenvironments. MPS enable real-time monitoring, morphological analysis, and protein quantification, enhancing our comprehension of cancer dynamics, including tumor migration, vascularization, and pre-metastatic niches. In this review, we explore innovative applications of MPS in investigating cancer metastasis, particularly focusing on organotropism. This interdisciplinary approach converges the field of science, engineering, and medicine, thereby illuminating a path toward groundbreaking discoveries in cancer research.

Advances in Hydrogel-Based Microfluidic Blood-Brain-Barrier Models in Oncology Research.

The intrinsic architecture and complexity of the brain restricts the capacity of therapeutic molecules to reach their potential targets, thereby limiting therapeutic possibilities concerning neurological ailments and brain malignancy. As conventional models fail to recapitulate the complexity of the brain, progress in the field of microfluidics has facilitated the development of advanced in vitro platforms that could imitate the in vivo microenvironments and pathological features of the blood–brain barrier (BBB). It is highly desirous that developed in vitro BBB-on-chip models serve as a platform to investigate cancer metastasis of the brain along with the possibility of efficiently screening chemotherapeutic agents against brain malignancies. In order to improve the proficiency of BBB-on-chip models, hydrogels have been widely explored due to their unique physical and chemical properties, which mimic the three-dimensional (3D) micro architecture of tissues. Hydrogel-based BBB-on-chip models serves as a stage which is conducive for cell growth and allows the exchange of gases and nutrients and the removal of metabolic wastes between cells and the cell/extra cellular matrix (ECM) interface. Here, we present recent advancements in BBB-on-chip models targeting brain malignancies and examine the utility of hydrogel-based BBB models that could further strengthen the future application of microfluidic devices in oncology research.

A Permanent Window for Investigating Cancer Metastasis to the Lung.

Metastasis, accounting for ~90% of cancer-related mortality, involves the systemic spread of cancer cells from primary tumors to secondary sites such as the bone, brain, and lung. Although extensively studied, the mechanistic details of this process remain poorly understood. While common imaging modalities, including computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI), offer varying degrees of gross visualization, each lacks the temporal and spatial resolution necessary to detect the dynamics of individual tumor cells. To address this, numerous techniques have been described for intravital imaging of common metastatic sites. Of these sites, the lung has proven especially challenging to access for intravital imaging owing to its delicacy and critical role in sustaining life. Although several approaches have previously been described for single-cell intravital imaging of the intact lung, all involve highly invasive and terminal procedures, limiting the maximum possible imaging duration to 6-12 h. Described here is an improved technique for the permanent implantation of a minimally invasive thoracic optical Window for High-Resolution Imaging of the Lung (WHRIL). Combined with an adapted approach to microcartography, the innovative optical window facilitates serial intravital imaging of the intact lung at single-cell resolution across multiple imaging sessions and spanning multiple weeks. Given the unprecedented duration of time over which imaging data can be gathered, the WHRIL can facilitate the accelerated discovery of the dynamic mechanisms underlying metastatic progression and numerous additional biologic processes within the lung.

A Permanent Window for Investigating Cancer Metastasis to the Lung

Here, we present a protocol for the surgical implantation of a permanently indwelling optical window for the murine thorax, which enables high-resolution, intravital imaging of the lung. The permanence of the window makes it well-suited to the study of dynamic cellular processes in the lung, especially those that are slowly evolving, such as metastatic progression of disseminated tumor cells.

Fluorometric Quantification of Single-Cell Velocities to Investigate Cancer Metastasis.

Hematogenous metastasis is a multistep, selectin-regulated process whose mechanisms remain poorly understood. To investigate this biological pathway of cancer dissemination and better understand circulating cancer cells, we developed a high-throughput methodology that integrates organ-on-chip-like microfluidic and photoconvertible protein technologies. Our approach can ascribe single-cell velocity as a traceable cell property for off-chip analysis of the direct relationships between cell molecular profiles and adhesive phenotypes in the context of physiologically relevant fluid flow. We interrogate how natively expressed selectin ligands relate to colon cancer cell rolling frequencies and velocities and provide context for previously reported disparities in invitro and invivo models of selectin-mediated adhesion and metastasis. This integrated methodology represents a versatile approach for the development of anti-metastatic therapeutics as well as to generate and test mechanistic hypotheses regarding spatiotemporal processes that occur over timescales of seconds to hours with single-cell resolution.

Beyond Enumeration: Functional and Computational Analysis of Circulating Tumor Cells to Investigate Cancer Metastasis.

Circulating tumor cells (CTCs) are defined as those cells that detach from a cancerous lesion and enter the bloodstream. While generally most CTCs are subjected to high shear stress, anoikis signals, and immune attack in the circulatory system, few are able to survive and reach a distant organ in a viable state, possibly leading to metastasis formation. A large number of studies, both prospective and retrospective, have highlighted the association between CTC abundance and bad prognosis in patients with various cancer types. Yet, beyond CTC enumeration, much less is known about the distinction between metastatic and nonmetastatic CTCs, namely those features that enable only some CTCs to survive and seed a cancerous lesion at a distant site. In addition, critical aspects such as CTC heterogeneity, mechanisms that trigger CTC intravasation and extravasation, as well as vulnerabilities of metastatic CTCs subpopulations are poorly understood. In this short review, we highlight recent studies that successfully adopted functional and computational analysis to gain insights into CTC biology. We also discuss approaches to overcome challenges that are associated with CTC isolation, molecular and computational analysis, and speculate regarding few open questions that currently frame the CTC research field.

Severe Combined ImmunoDeficient (SCID) mice in biomedical research

Mice have been used in cancer research since the last decade of the 19th century. In 1921 inbred strains, that were predisposed to developing tumors, were bred and became available to cancer researchers. The nude mouse, a hairless mutantdiscovered in 1962, is immunodeficient, and thus does not reject tumor transplantations from other species. It lacks a thymus, which is essential for the production of T-cells, lymphocytes that are essential for cellular immunity. In 1983 mice with severecombined immune deficiency (Prkdcscld, commonly referred to as seid) were discovered. Seid mice are even more immunodeficient than nude mice. Tumors from other species are transplanted into seid mice easier. In 1988 two groups of researchers almostsimultaneously succeeded in transplanting elements of the human immune system into seid mice. They had used totally different approaches in creating their human-mouse chimeras. This chimera, named the hu-PBL- seid, was also able to produce humantetanus antibodies when injected with tetanus toxin, further demonstrating that its immune system was functioning as though itwas naturally human. Severe Combined ImmunoDeficient (seid) mice are homozygous for the mutant autosomal recessive gene"seid", which is located at the centromeric end of chromosome 16. Since these mice lack mature, functional lymphocytes, they arehighly susceptible to lethal opportunistic infections. For this reason, they should be maintained in a pathogen free environment. Someseid mice, by an unexplained mechanism, eventually develop minute levels of Β cells and a rudimentary antibody response and are commonly referred to as "leaky". Different genetic manipulations are used to overcome this obstacle. The transfer of the seid mutation onto the Non-Obese Diabetic (NOD), BEIGE (beige mutation results in cytotoxic Τ cell and macrophage defects as well as selective impairment of NK cell functions) and other strains has led to better engraftment of transferred human cells. Lately, mice with targeted mutations have been engineered, including animals with disruption of the recombination activating gene-1(Rag-1) or (Rag-2), β2 microglobulin (B2m) and perforin (PRF1) genes. Any possible combination of the above mentioned mutantshas led to the development of humanized mouse models providing more straightforward assay systems for the study of the human hematolymphoid system. Our personal experience on the use οι seid mice in biomedical research relates to the development of animal models to investigate cancer metastasis in human bone.

Abstract A15: Development of an in vitro 3D vessel-spheroid model for investigating cancer metastasis

Abstract During metastasis, cells break free from the primary tumor, migrate through the stroma and enter either the vascular or lymph systems to disseminate into secondary sites. To better understand this process, many groups have developed in vitro models of cancer metastasis using microfluidic based platforms to mimic the tumor microenvironment and the intravasation/extravasation of tumor cells. While these models have provided significant new insights into the mechanisms by which metastatic cells move across the endothelium, they are most often focused on the movement of single cells. Notably, there is significant clinical evidence to suggest that tumor cells can travel collectively though the stroma and can circulate as cell aggregates in the vasculature. Recent advances in the understanding of cancer metastasis have shown that cancer may move more aggressively as a collection of cell when traversing the extracellular matrix (ECM) of the tumor microenvironment as opposed to more studied singular cellular motif. To better mimic these collective movements, we have developed a model that incorporates the following essential elements that exist in the tumor microenvironment: a cylindrical channel lined with a confluent monolayer of endothelial cells, a metastatic tumor analog in close proximity to the channel, the ability to incorporate flow with tunable properties to simulate shear stress due to blood flow, and a tunable collagen microenvironment. Briefly, in a 3D printed cube, Type 1 collagen is added at physiological stiffness. As the collagen is polymerizing in the device, a metastatic tumor analog (spheroid) consisting of labeled MDA-MB-231 cells is placed in proximity of the vessel that is lined with endothelial cells. The platform allows for the visualization of metastatic cell intravasation using confocal microscopy. Notably, this model is easy to build and implement with fairly accessible tools and without the use of a clean room or microfabrication facilities. Importantly, going forward this model has the ability to study the cellular behavior post-intravasation due to the incorporation of physiological flows within the channel. Citation Format: Adam Munoz, Joseph Miller, Cynthia A. Reinhart-King. Development of an in vitro 3D vessel-spheroid model for investigating cancer metastasis. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A15.

Tongue Tumor Satellite in Predicting Occult Neck Metastasis

OBJECTIVE: Tongue cancer is well-known for high potential of locoregional metastasis. However, the controversy of electively treating clinical N0 neck still exists. Though numerous risk factors related to cervical occult nodal metastasis (ONM) have been investigated, the ability of tumor spreading, which is a phenomenon that results from tumor intrinsic behavior and the interaction with surrounding environment, has seldom been addressed. The mutual reaction between tumor cells and the host environment has drawn increasing attention in investigating cancer metastasis. This study aims to explore the clinical significance of tumor spreading capacity in predicting the potential neck metastasis of tongue cancer. METHOD: The association between tumor satellite distance (TSD), a parameter of tumor spreading ability, and ONM was investigated. During 2003 to 2006, patients registered in the Department of Otolaryngology, National Taiwan University Hospital with fresh tongue cancer were retrospectively analyzed. RESULTS: 542 patients with freshly diagnosed tongue cancer were evaluated. Of 58 eligible enrolled patients with N0 neck, positive ONM was detected in 9 (16%) patients while negative ONM in 49 (84%). The majority of negative ONM group had TSD less than 0.5 mm while in positive ONM group, greater than 1.5 mm. Quantitatively, the average TSD in positive ONM group was 2.7 mm (s.d.1.9 mm) in contrast to that in negative ONM, 0.7 mm (s.d.0.8 mm) (p 0.019). Stratified by TSD of 0.5 mm, 1.0 mm, and 1.5 mm respectively, the statistical significance of difference increased correspondingly (p 0.0255, 0.0019, and 0.0007). CONCLUSION: The results indicate that TSD is an important pathological parameter that is useful in reflecting the status of cervical nodal metastasis. It might be used as an indicator of possible cervical subclinical disease and as a guideline of deciding the necessity and modality of neck treatment.

A novel nude mouse model of liver metastasis and peritoneal dissemination from the same human pancreatic cancer line.

Recently, several mice models have been used for investigating cancer metastasis. However, there are no metastatic and peritoneal dominated variants from the same parental cell line. To elucidate the mechanisms of metastasis, we established highly liver metastatic and peritoneal disseminated models in nude mice, and then characterized several factors related to metastasis in these cells. We established a series of well-characterized sublines that showed metastatic potentials to different organ sites of nude mice. Two sublines were selected sequentially from the parental pancreatic cancer cell line, HPC-4, resulting in a highly liver metastatic cell line, HPC-4H4, and a highly peritoneal disseminated cell line, HPC-4P4a. Using these three cell lines, we investigated several biologic properties and mRNA levels of differentially expressed genes involved in cancer metastasis. The tumorigenicity, the motile activity, and the adhesive activity of metastatic sublines were higher than those of parental HPC-4 cells. Macroscopic and microscopic findings and the DNA ploidy pattern were the same among the three cell lines. In addition, HPC-4H4 cells expressed clearly higher levels of vascular endothelial growth factor and IL-8 expression than did HPC-4P4a cells. In fluorescence-activated cell sorter analysis of adhesion molecules, the expression of integrin-alpha2 was enhanced in HPC-4 cells, integrin-alphavbeta5 was enhanced in HPC-4H4 cells, and integrin-alpha3 was enhanced in HPC-4P4a cells. Osteopontin, vascular endothelial growth factor, and hepatocyte growth factor were among the genes that were upregulated in HPC-4H4 cells compared with HPC-4P4a cells. HPC-4P4a cells did not metastasize to the liver by intrasplenic injection. Conversely, HPC-4H4 cells metastasized remarkably to the peritoneum by intraabdominal injection. These sublines are the first reported liver metastatic and peritoneal disseminated models derived from the same parental cell lines. The results of our study suggest that the process of hematogenous metastasis is not the same as that of peritoneal dissemination.

A mono-block formalin-fixation method for investigating cancer metastasis.

A mono-block formalin-fixation method is proposed for investigating cancer metastasis in man.