Establishment of a gastric cancer subline with high metastatic potential using a novel microfluidic system

A novel radial co-culture microfluidic device for parallel and control detection of tumor cell invasiveness

Metastasis is responsible for the majority of cancer-related deaths, and tumor cell invasion is a critical step in the cancer metastatic cascade. Traditional invasion analysis using transwell assays and immunodeficient mouse models struggles to control tumor microenvironment factors, such as various biochemical signals and cell types. A microfluidic chip system has emerged as an important tool for invasion analysis, but the simultaneous parallel and controlled experiments within the same group of tumor cells remain challenging. Here, we developed a new three-dimensional co-culture microfluidic device to investigate tumor invasion. This device consists of three concentric circles and is divided into four identical regions. Each region includes a tumor cell region, an invasion channel and a co-culture channel. Additionally, the four identical regions allow for four specific groups of parallel or control analysis surrounding the same group of tumor cells. Thus, our device enables the comparison of invasion among the same group of cells under different conditions, avoiding the discrepancies in invasion that arise when the treatment factors differ across different groups of tumor cells. Using experimental examinations and numerical simulations, we verified the capability of the device for parallel and controlled analysis of tumor invasion in response to different stimuli, including chemokines, drugs and cellular factors secreted from co-cultured cells. Furthermore, we found that in a co-culture environment with cancer-associated fibroblasts, the invasiveness of LoVo cells and their resistance to 5-fluorouracil treatment were enhanced. This innovative approach allows for easy, parallel and controlled assays to study tumor cell invasion with the advantages of multiplexing and simplicity. The method provides straightforward, repeatable control over cell-biochemical signals and cell-cell interactions, making it a valuable tool for accurately evaluating tumor invasion in metastasis studies.

Breaking the mold: 3D cell cultures reshaping the future of cancer research

Despite extensive efforts to unravel tumor behavior and develop anticancer therapies, most treatments fail when advanced to clinical trials. The main challenge in cancer research has been the absence of predictive cancer models, accurately mimicking the tumoral processes and response to treatments. The tumor microenvironment (TME) shows several human-specific physical and chemical properties, which cannot be fully recapitulated by the conventional 2D cell cultures or the in vivo animal models. These limitations have driven the development of novel in vitro cancer models, that get one step closer to the typical features of in vivo systems while showing better species relevance. This review introduces the main considerations required for developing and exploiting tumor spheroids and organoids as cancer models. We also detailed their applications in drug screening and personalized medicine. Further, we show the transition of these models into novel microfluidic platforms, for improved control over physiological parameters and high-throughput screening. 3D culture models have provided key insights into tumor biology, more closely resembling the in vivo TME and tumor characteristics, while enabling the development of more reliable and precise anticancer therapies.

Improving tumor microenvironment assessment in chip systems through next-generation technology integration

The tumor microenvironment (TME) comprises a diverse array of cells, both cancerous and non-cancerous, including stromal cells and immune cells. Complex interactions among these cells play a central role in driving cancer progression, impacting critical aspects such as tumor initiation, growth, invasion, response to therapy, and the development of drug resistance. While targeting the TME has emerged as a promising therapeutic strategy, there is a critical need for innovative approaches that accurately replicate its complex cellular and non-cellular interactions; the goal being to develop targeted, personalized therapies that can effectively elicit anti-cancer responses in patients. Microfluidic systems present notable advantages over conventional in vitro 2D co-culture models and in vivo animal models, as they more accurately mimic crucial features of the TME and enable precise, controlled examination of the dynamic interactions among multiple human cell types at any time point. Combining these models with next-generation technologies, such as bioprinting, single cell sequencing and real-time biosensing, is a crucial next step in the advancement of microfluidic models. This review aims to emphasize the importance of this integrated approach to further our understanding of the TME by showcasing current microfluidic model systems that integrate next-generation technologies to dissect cellular intra-tumoral interactions across different tumor types. Carefully unraveling the complexity of the TME by leveraging next generation technologies will be pivotal for developing targeted therapies that can effectively enhance robust anti-tumoral responses in patients and address the limitations of current treatment modalities.

Establishment of a novel microfluidic co-culture system for simultaneous analysis of multiple indicators of gefitinib sensitivity in colorectal cancer cells

The therapeutic effect of gefitinib on colorectal cancer (CRC) is unclear, but it has been reported that stromal cells in the tumor microenvironment may have an impact on drug sensitivity. Herein, we established a microfluidic co-culture system and explored the sensitivity of CRC cells co-cultured with cancer-associated fibroblasts (CAFs) to gefitinib. The system consisted of a multichannel chip and a Petri dish. The chambers in the chip and dish were designed to continuously supply nutrients for long-term cell survival and create chemokine gradients for driving cell invasion without any external equipment. Using this system, the proliferation and invasiveness of cells were simultaneously evaluated by quantifying the area of cells and the migration distance of cells. In addition, the system combined with live cell workstation could evaluate the dynamic drug response of co-cultured cells and track individual cell trajectories in real-time. When CRC cells were co-cultured with CAFs, CAFs promoted CRC cell proliferation and invasion and reduced the sensitivity of cells to gefitinib through the exosomes secreted by CAFs. Furthermore, the cells that migrated out of the chip were collected, and EMT-related markers were determined by immunofluorescent and western blot assays. The results demonstrated that CAFs affected the response of CRC cells to gefitinib by inducing EMT, providing new ideas for further research on the resistance mechanism of gefitinib. This suggests that targeting CAFs or exosomes might be a new approach to enhance CRC sensitivity to gefitinib, and our system could be a novel platform for investigating the crosstalk between tumor cells and CAFs and understanding multiple biological changes of the tumor cells in the tumor microenvironment.

On-chip modeling of tumor evolution: Advances, challenges and opportunities

Tumor evolution is the accumulation of various tumor cell behaviors from tumorigenesis to tumor metastasis and is regulated by the tumor microenvironment (TME). However, the mechanism of solid tumor progression has not been completely elucidated, and thus, the development of tumor therapy is still limited. Recently, Tumor chips constructed by culturing tumor cells and stromal cells on microfluidic chips have demonstrated great potential in modeling solid tumors and visualizing tumor cell behaviors to exploit tumor progression. Herein, we review the methods of developing engineered solid tumors on microfluidic chips in terms of tumor types, cell resources and patterns, the extracellular matrix and the components of the TME, and summarize the recent advances of microfluidic chips in demonstrating tumor cell behaviors, including proliferation, epithelial-to-mesenchymal transition, migration, intravasation, extravasation and immune escape of tumor cells. We also outline the combination of tumor organoids and microfluidic chips to elaborate tumor organoid-on-a-chip platforms, as well as the practical limitations that must be overcome.

Integrative microphysiological tissue systems of cancer metastasis to the liver

The liver is the most commonly involved organ in metastases from a wide variety of solid tumors. The use of biologically and cellularly complex liver tissue systems have shown that tumor cell behavior and therapeutic responses are modulated within the liver microenvironment and in ways distinct from the behaviors in the primary locations. These microphysiological systems have provided unexpected and powerful insights into the tumor cell biology of metastasis. However, neither the tumor nor the liver exist in an isolated tissue situation, having to function within a complete body and respond to systemic events as well as those in other organs. To examine the influence of one organ on the function of other tissues, microphysiological systems are being linked. Herein, we discuss extending this concept to tumor metastases by integrating complex models of the primary tumor with the liver metastatic environment. In addition, inflammatory organs and the immune system can be incorporated into these multi-organ systems to probe the effects on tumor behavior and cancer treatments.

Evolution of Metastasis Study Models toward Metastasis-On-A-Chip: The Ultimate Model?

For decades, several attempts have been made to obtain a mimetic model for the study of metastasis, the reason of most of deaths caused by cancer, in order to solve the unknown phenomena surrounding this disease. To better understand this cellular dissemination process, more realistic models are needed that are capable of faithfully recreating the entire and essential tumor microenvironment (TME). Thus, new tools known as tumor-on-a-chip and metastasis-on-a-chip have been recently proposed. These tools incorporate microfluidic systems and small culture chambers where TME can be faithfully modeled thanks to 3D bioprinting. In this work, a literature review has been developed about the different phases of metastasis, the remaining unknowns and the use of new models to study this disease. The aim is to provide a global vision of the current panorama and the great potential that these systems have for in vitro translational research on the molecular basis of the pathology. In addition, these models will allow progress toward a personalized medicine, generating chips from patient samples that mimic the original tumor and the metastatic process to perform a precise pharmacological screening by establishing the most appropriate treatment protocol.

Engineering Patient-on-a-Chip Models for Personalized Cancer Medicine

Traditional in vitro and in vivo models typically used in cancer research have demonstrated a low predictive power for human response. This leads to high attrition rates of new drugs in clinical trials, which threaten cancer patient prognosis. Tremendous efforts have been directed towards the development of a new generation of highly predictable pre-clinical models capable to reproduce in vitro the biological complexity of the human body. Recent advances in nanotechnology and tissue engineering have enabled the development of predictive organs-on-a-chip models of cancer with advanced capabilities. These models can reproduce in vitro the complex three-dimensional physiology and interactions that occur between organs and tissues in vivo, offering multiple advantages when compared to traditional models. Importantly, these models can be tailored to the biological complexity of individual cancer patients resulting into biomimetic and personalized cancer patient-on-a-chip platforms. The individualized models provide a more accurate and physiological environment to predict tumor progression on patients and their response to drugs. In this chapter, we describe the latest advances in the field of cancer patient-on-a-chip, and discuss about their main applications and current challenges. Overall, we anticipate that this new paradigm in cancer in vitro models may open up new avenues in the field of personalized - cancer - medicine, which may allow pharmaceutical companies to develop more efficient drugs, and clinicians to apply patient-specific therapies.

miR-135a inhibits tumor metastasis and angiogenesis by targeting FAK pathway

Tumor metastasis has been the major cause of recurrence and death in patients with gastric cancer. Here, we find miR-135a has a decreased expression in the metastatic cell lines compared with its parental cell lines by analyzing microRNA array. Further results show that miR-135a is downregulated in the majority of human gastric cancer tissues and cell lines. Decreased expression of miR-135a is associated with TNM stage and poor survival. Besides, regaining miR-135a in gastric cancer cells obviously inhibits tumor growth, migration, invasion and angiogenesis by targeting focal adhesion kinase (FAK) pathway. Bioinformatics analysis and molecular experiments further prove that miR-135a is a novel downstream gene of tumor suppressor p53. Blocking FAK with its inhibitor can also enhance miR-135a expression through inducing p53. In summary, this study reveals the expression and function of miR-135a in gastric cancer and uncovers a novel regulatory mechanism of miR-135a.