Responses of Cellular Adhesion Strength and Stiffness to Fluid Shear Stress during Tumor Cell Rolling Motion

Cancer cell response to extrinsic and intrinsic mechanical cue: opportunities for tumor apoptosis strategies

Increasing studies have revealed the importance of mechanical cues in tumor progression, invasiveness and drug resistance. During malignant transformation, changes manifest in either the mechanical properties of the tissue or the cellular ability to sense and respond to mechanical signals. The major focus of the review is the subtle correlation between mechanical cues and apoptosis in tumor cells from a mechanobiology perspective. To begin, we focus on the intracellular force, examining the mechanical properties of the cell interior, and outlining the role that the cytoskeleton and intracellular organelle-mediated intracellular forces play in tumor cell apoptosis. This article also elucidates the mechanisms by which extracellular forces guide tumor cell mechanosensing, ultimately triggering the activation of the mechanotransduction pathway and impacting tumor cell apoptosis. Finally, a comprehensive examination of the present status of the design and development of anti-cancer materials targeting mechanotransduction is presented, emphasizing the underlying design principles. Furthermore, the article underscores the need to address several unresolved inquiries to enhance our comprehension of cancer therapeutics that target mechanotransduction.

Organ-on-Chip: Advancing Nutraceutical Testing for Improved Health Outcomes

The recent global wave of organic food consumption and the vitality of nutraceuticals for human health benefits has driven the need for applying scientific methods for phytochemical testing. Advanced in vitro models with greater physiological relevance than conventional in vitro models are required to evaluate the potential benefits and toxicity of nutraceuticals. Organ-on-chip (OOC) models have emerged as a promising alternative to traditional in vitro models and animal testing due to their ability to mimic organ pathophysiology. Numerous studies have demonstrated the effectiveness of OOC models in identifying pharmaceutically relevant compounds and accurately assessing compound-induced toxicity. This review examines the utility of traditional in vitro nutraceutical testing models and discusses the potential of OOC technology as a preclinical testing tool to examine the biomedical potential of nutraceuticals by reducing the need for animal testing. Exploring the capabilities of OOC models in carrying out plant-based bioactive compounds can significantly contribute to the authentication of nutraceuticals and drug discovery and validate phytochemicals medicinal characteristics. Overall, OOC models can facilitate a more systematic and efficient assessment of nutraceutical compounds while overcoming the limitations of current traditional in vitro models.

Quantifying the hydrodynamic stress for bioprocesses

Hydrodynamic stress is an influential physical parameter for various bioprocesses, affecting the performance and viability of the living organisms. However, different approaches are in use in various computational and experimental studies to calculate this parameter (including its normal and shear subcomponents) from velocity fields without a consensus on which one is the most representative of its effect on living cells. In this letter, we investigate these different methods with clear definitions and provide our suggested approach which relies on the principal stress values providing a maximal distinction between the shear and normal components. Furthermore, a numerical comparison is presented using the computational fluid dynamics simulation of a stirred and sparged bioreactor. It is demonstrated that for this specific bioreactor, some of these methods exhibit quite similar patterns throughout the bioreactor-therefore can be considered equivalent-whereas some of them differ significantly.

Circulating Tumor Cells in Cancer Diagnostics and Prognostics by Single-Molecule and Single-Cell Characterization

Circulating tumor cells (CTCs) represent an interesting source of biomarkers for diagnosis, prognosis, and the prediction of cancer recurrence, yet while they are extensively studied in oncobiology research, their diagnostic utility has not yet been demonstrated and validated. Their scarcity in human biological fluids impedes the identification of dangerous CTC subpopulations that may promote metastatic dissemination. In this Perspective, we discuss promising techniques that could be used for the identification of these metastatic cells. We first describe methods for isolating patient-derived CTCs and then the use of 3D biomimetic matrixes in their amplification and analysis, followed by methods for further CTC analyses at the single-cell and single-molecule levels. Finally, we discuss how the elucidation of mechanical and morphological properties using techniques such as atomic force microscopy and molecular biomarker identification using nanopore-based detection could be combined in the future to provide patients and their healthcare providers with a more accurate diagnosis.

Nanoscopic Characterization of Cell Migration under Flow Using Optical and Electron Microscopy

Hematopoietic stem/progenitor cell (HSPC) and leukemic cell homing is an important biological phenomenon that takes place through essential interactions with adhesion molecules on an endothelial cell layer. The homing process of HSPCs begins with the tethering and rolling of the cells on the endothelial layer, which is achieved by the interaction between selectins on the endothelium to the ligands on HSPC/leukemic cells under shear stress of the blood flow. Although many studies have been based on in vitro conditions of the cells rolling over recombinant proteins, significant challenges remain when imaging HSPC/leukemic cells on the endothelium, a necessity when considering characterizing cell-to-cell interaction and rolling dynamics during cell migration. Here, we report a new methodology that enables imaging of stem-cell-intrinsic spatiotemporal details during its migration on an endothelium-like cell monolayer. We developed optimized protocols that preserve transiently appearing structures on HSPCs/leukemic cells during its rolling under shear stress for fluorescence and scanning electron microscopy characterization. Our new experimental platform is closer to in vivo conditions and will contribute to indepth understanding of stem-cell behavior during its migration and cell-to-cell interaction during the process of homing.

Applications of Microfluidics and Organ-on-a-Chip in Cancer Research

Taking the life of nearly 10 million people annually, cancer has become one of the major causes of mortality worldwide and a hot topic for researchers to find innovative approaches to demystify the disease and drug development. Having its root lying in microelectronics, microfluidics seems to hold great potential to explore our limited knowledge in the field of oncology. It offers numerous advantages such as a low sample volume, minimal cost, parallelization, and portability and has been advanced in the field of molecular biology and chemical synthesis. The platform has been proved to be valuable in cancer research, especially for diagnostics and prognosis purposes and has been successfully employed in recent years. Organ-on-a-chip, a biomimetic microfluidic platform, simulating the complexity of a human organ, has emerged as a breakthrough in cancer research as it provides a dynamic platform to simulate tumor growth and progression in a chip. This paper aims at giving an overview of microfluidics and organ-on-a-chip technology incorporating their historical development, physics of fluid flow and application in oncology. The current applications of microfluidics and organ-on-a-chip in the field of cancer research have been copiously discussed integrating the major application areas such as the isolation of CTCs, studying the cancer cell phenotype as well as metastasis, replicating TME in organ-on-a-chip and drug development. This technology’s significance and limitations are also addressed, giving readers a comprehensive picture of the ability of the microfluidic platform to advance the field of oncology.

A universal microfluidic approach for integrated analysis of temporal homocellular and heterocellular signaling and migration dynamics

Microfluidics offers precise and dynamic control of microenvironments for the study of temporal cellular responses. However, recent research focusing solely on either homocellular (single-cell, population) or heterocellular response may yield insufficient output, which possibly leads to partial comprehension about the underlying mechanisms of signaling events and corresponding cellular behaviors. Here, a universal microfluidic approach is developed for integrated analysis of temporal signaling and cell migration dynamics in multiple cellular contexts (single-cell, population and coculture). This approach allows to confine the desired number or mixture of specific cell sample types in a single device. Precise single cell seeding was achieved manually with bidirectional controllability. Coupled with time-lapse imaging, temporal cellular responses can be observed with single-cell resolution. Using NIH3T3 cells stably expressing signal transducer and activator of transcription 1/2 (STAT1/2) activity biosensors, temporal STAT1/2 activation and cell migration dynamics were explored in isolated single cells, populations and cocultures stimulated with temporal inputs, such as single-pulse and continuous signals of interferon γ (IFNγ) or lipopolysaccharide (LPS). We demonstrate distinct dynamic responses of fibroblasts in different cellular contexts. Our presented approach facilitates a multi-dimensional understanding of STAT signaling and corresponding migration behaviors.

A Transcriptome Sequencing Study on Genome-Wide Gene Expression Differences of Lung Cancer Cells Modulated by Fucoidan

Fucoidan has received increasing attention in anti-(lung) tumors. However, the effect of fucoidan on the gene changes of lung cancer cells (LCCs) has not been examined systematically. Herein, we investigate the effect of fucoidan on the phenotypes of LCCs and their gene expression by transcriptome sequencing analysis. The phenotypes of LCCs are significantly inhibited by fucoidan. Importantly, compared to LCCs, 1 mg/ml fucoidan has no effect on the phenotypes of normal cells. Further, 6,930 differentially expressed genes (DEGs) in the transcriptome of LCCs (3,501 up-regulated and 3,429 down-regulated genes) are detected via RNA-sequencing between the fucoidan and control groups. Gene Ontology analysis confirms that DEGs are reflected in DNA replication, cell-substrate junction, regulation of cell cycle phase transition, apoptosis, focal adhesion, cadherin binding, and cell adhesion molecule binding. Thus, our findings on the transcriptomic level highlight the therapeutic potential of fucoidan for lung cancer treatment.

Cancer-on-a-Chip: Models for Studying Metastasis

Simple Summary

Microfluidic-based cancer-on-a-chip models are powerful tools to study the tumor microenvironment (TME). Two-dimensional cell culture cannot recapitulate TME. In vivo animal models can better represent the TME, but their physiology is vastly different from that of humans. Although three-dimensional tumor models can bridge the gap between in vitro and in vivo examination, they are still unable to test many crucial cues from the TME, such as mechanical cues, cell–cell, and cell–extracellular interactions. Cancer-on-a-chip platforms enable studying the metastatic process in a step-wise manner with precise control. We present an overview of the recent advances in cancer-on-a-chip models on metastasis including models that mimic mechanical cues. This review article will provide knowledge of the latest progress made on cancer-on-a-chip models.

Abstract

The microfluidic-based cancer-on-a-chip models work as a powerful tool to study the tumor microenvironment and its role in metastasis. The models recapitulate and systematically simplify the in vitro tumor microenvironment. This enables the study of a metastatic process in unprecedented detail. This review examines the development of cancer-on-a-chip microfluidic platforms at the invasion/intravasation, extravasation, and angiogenesis steps over the last three years. The on-chip modeling of mechanical cues involved in the metastasis cascade are also discussed. Finally, the popular design of microfluidic chip models for each step are discussed along with the challenges and perspectives of cancer-on-a-chip models.

Mechanical Properties in the Glioma Microenvironment: Emerging Insights and Theranostic Opportunities

Gliomas represent the most common malignant primary brain tumors, and a high-grade subset of these tumors including glioblastoma are particularly refractory to current standard-of-care therapies including maximal surgical resection and chemoradiation. The prognosis of patients with these tumors continues to be poor with existing treatments and understanding treatment failure is required. The dynamic interplay between the tumor and its microenvironment has been increasingly recognized as a key mechanism by which cellular adaptation, tumor heterogeneity, and treatment resistance develops. Beyond ongoing lines of investigation into the peritumoral cellular milieu and microenvironmental architecture, recent studies have identified the growing role of mechanical properties of the microenvironment. Elucidating the impact of these biophysical factors on disease heterogeneity is crucial for designing durable therapies and may offer novel approaches for intervention and disease monitoring. Specifically, pharmacologic targeting of mechanical signal transduction substrates such as specific ion channels that have been implicated in glioma progression or the development of agents that alter the mechanical properties of the microenvironment to halt disease progression have the potential to be promising treatment strategies based on early studies. Similarly, the development of technology to measure mechanical properties of the microenvironment in vitro and in vivo and simulate these properties in bioengineered models may facilitate the use of mechanical properties as diagnostic or prognostic biomarkers that can guide treatment. Here, we review current perspectives on the influence of mechanical properties in glioma with a focus on biophysical features of tumor-adjacent tissue, the role of fluid mechanics, and mechanisms of mechanical signal transduction. We highlight the implications of recent discoveries for novel diagnostics, therapeutic targets, and accurate preclinical modeling of glioma.

Shear stress regulates the migration of suspended breast cancer cells by nuclear lamina protein A/C and large tumor suppressor through yes-associated protein

Breast cancer is life threatening among women because its migration by hematogenous metastasis, where, besides biochemical cues, breast circulating tumor cells (CTCs) expose to suspension state and shear stress. However, the combined effects of these mechanical factors on CTCs migration were unclear. Here, suspension state and shear stress were loaded to breast tumor cells (BTCs) to mimic two mechanical cues in the mechanical environment of breast CTCs and the mechanobiological mechanism of suspension state and shear stress regulating the migration of (BTCs) was investigated. The migration and nuclear lamina protein A/C (Lamin A/C) accumulation were enhanced in MDA-MB-231 and SK-BR-3 BTCs exposed to shear stress though lower than that of suspended cells with different yes-associated protein (YAP) subcellular localization. Knockdown of LMNA downregulated and upregulated YAP targets in suspended BTCs and BTCs exposed to shear stress, respectively, which inhibited MDA-MB-231 BTCs migration in vitro and in vivo. Large tumor suppressor (LATS) responded to suspension state and shear stress, knockdown of which decreased the migration of MDA-MB-231 BTCs. These findings uncover the mechanobiological mechanism that suspension state and shear stress antagonistically promote BTCs migration by Lamin A/C and LATS through YAP and the potential for targeting YAP in CTCs prognosis. Shear stress regulates suspended breast cancer cells migration by Lamin A/C and LATS through YAP.

Progress in the mechanical modulation of cell functions in tissue engineering

In mammals, mechanics at multiple stages-nucleus to cell to ECM-underlie multiple physiological and pathological functions from its development to reproduction to death. Under this inspiration, substantial research has established the role of multiple aspects of mechanics in regulating fundamental cellular processes, including spreading, migration, growth, proliferation, and differentiation. However, our understanding of how these mechanical mechanisms are orchestrated or tuned at different stages to maintain or restore the healthy environment at the tissue or organ level remains largely a mystery. Over the past few decades, research in the mechanical manipulation of the surrounding environment-known as substrate or matrix or scaffold on which, or within which, cells are seeded-has been exceptionally enriched in the field of tissue engineering and regenerative medicine. To do so, traditional tissue engineering aims at recapitulating key mechanical milestones of native ECM into a substrate for guiding the cell fate and functions towards specific tissue regeneration. Despite tremendous progress, a big puzzle that remains is how the cells compute a host of mechanical cues, such as stiffness (elasticity), viscoelasticity, plasticity, non-linear elasticity, anisotropy, mechanical forces, and mechanical memory, into many biological functions in a cooperative, controlled, and safe manner. High throughput understanding of key cellular decisions as well as associated mechanosensitive downstream signaling pathway(s) for executing these decisions in response to mechanical cues, solo or combined, is essential to address this issue. While many reports have been made towards the progress and understanding of mechanical cues-particularly, substrate bulk stiffness and viscoelasticity-in regulating the cellular responses, a complete picture of mechanical cues is lacking. This review highlights a comprehensive view on the mechanical cues that are linked to modulate many cellular functions and consequent tissue functionality. For a very basic understanding, a brief discussion of the key mechanical players of ECM and the principle of mechanotransduction process is outlined. In addition, this review gathers together the most important data on the stiffness of various cells and ECM components as well as various tissues/organs and proposes an associated link from the mechanical perspective that is not yet reported. Finally, beyond addressing the challenges involved in tuning the interplaying mechanical cues in an independent manner, emerging advances in designing biomaterials for tissue engineering are also explored.