Figure 6. Components of functional tumor-on-a-chip system: (
a) material selection and microchip fabrication; (
b) selection of biological material; (
c) peripheral equipment (Incubators, Pumps for perfusion, Mechanical stimulation, Controls and sensors, Microscope).
OOC systems have the potential to replace animal models in drug testing and provide insights into organ-level responses in a more human-relevant manner. Those devices permit studying human physiology and disease more realistically and accurately than traditional cell cultures or animal models. Some OOC systems are currently used in research and medicine (Table 3).
Table 3.
Types of organ-on-chip models used in research and medicine.
Microfluidics is a technology that allows for the development of highly advanced in vitro tumor models. These models closely resemble the physiological and structural characteristics of tumors found in the human body. So, tumor-on-chips are used to study tumor biology and gain insights into tumor behavior, which can ultimately lead to more effective therapies
[156][155]. The tumor-on-chip creates a system in vitro replicating key aspects of the in vivo tumor microenvironment, including the mechanical forces, fluid flow, and nutrient gradients the cells experience in the body. Tumors are complex environments, including various cell types, involving tumor, immune, and stromal cells. By incorporating multiple cell types into tumor-on-chips, researchers can more accurately replicate the complexity of the in vivo tumor microenvironment and improve the accuracy of their results. All of these allow researchers to study the behavior of cancer cells in a more realistic and controlled situation, which can provide new insights into tumor growth and other important aspects of cancer biology. In medicine, tumor-on-chips can be used to grow and study tumor cells, and researchers use microscale tumor models to analyze blood or tissue samples for cancer-associated biomarkers or cancer-related gene mutations
[157,158][156][157]. Tumor-on-chips have a multitude of potential applications, including drug discovery, optimizing time-and-dose drug delivery, assessing the effectiveness of other delivery methods, developing point-of-care diagnostics, and offering the possibility of approaching personalized medicine to be approached more easily
[159][158].
Microfluidic technology has several advantages over traditional methods in medicine, such as improved precision, reduced sample sizes, and increased speed and automation. In medicine, microfluidic technology promises to revolutionize, especially the field of oncology, by providing real information regarding the tumor microenvironment and the tumor structure
[160][159]. This technology ensures the creation of microfluidic chips, devices that can provide a better understanding of the behavior of tumor cells and how they respond to different types of treatment. In addition, advanced imaging techniques, such as live cell imaging, can be used to monitor the response of cancer cells to therapy in real time. Using these tools and techniques, researchers can provide new insights into how cancer cells respond to therapy and optimize treatment strategies.
Microfluidic technology offers unique opportunities for various diagnostic applications, including infectious disease detection, biomarker monitoring, or the possibility of combining with next-generation sequencing as futuristic genetic analysis
[161][160]. This technology has the advantage that all analytical steps, such as sample preparation, mixing, and detection, are integrated into a single platform. Such devices play a crucial role in the development of liquid biopsy techniques, which involve the analysis of tumor-derived components from body fluids such as blood or urine. The devices can efficiently capture and isolate circulating tumor cells (CTCs), exosomes, or cell-free DNA from these samples, providing valuable information about tumor progression and treatment response
[162,163][161][162]. Through this technology, miniaturized, biomimetic environments that mimic the complex conditions in the human body can be created. Microfluidic chips enable the simultaneous testing of multiple drug candidates, accelerating the discovery and optimization of new cancer therapies. Furthermore, by incorporating microscale channels, valves, and pumps, microfluidic devices can precisely control drug release by directly modulating the flow rates, composition, and size of the delivery system at tumor sites. This technology enables the targeted delivery of chemotherapy drugs directly into the tumor, improving drug efficacy, minimizing systemic toxicity, and reducing side effects
[164][163]. These technologies can process small sample volumes, making them ideal for analyzing limited biological material such as circulating tumor cells or rare cell populations
[165][164].
Microfluidic technology is a rapidly evolving field that aims to recreate the functions and physiology of human organs on a microscale device. While it holds immense potential for various applications, it also has advantages and disadvantages (Figure 6).
This technology presents numerous advantages because it provides a more accurate representation of human organs than traditional in vitro cell cultures or animal models (mimicking the microenvironment, cellular interactions, and physiological responses of human organs). It also enables the simultaneous testing of multiple compounds or treatments and provides valuable screening and rapid evaluation of drug candidates, reducing the costs and time associated with traditional drug development processes.
The technology offers an ethical alternative for testing drug efficacy and toxicity, thus minimizing the need for animal experimentation. A significant advantage is that microfluidic chips can be customized to reproduce specific patient conditions or genetic profiles, and it opens up possibilities for personalized medicine. Being a state-of-the-art technology, it incorporates sensors and imaging techniques for real-time monitoring of cellular responses, biochemical markers, and physiological parameters. All this ensures the obtaining of valuable data about the effects of drugs, the disease’s progression, and the tissues’ functionality, improving their understanding of the physiology of the organs.
However, several disadvantages of microfluidic technology must be mentioned: the high complexity of designing and manufacturing devices with precise cellular arrangements and functional integration. Last but not least, the high cost and the technical challenges of developing and maintaining chip systems can limit their widespread adoption.
This technology has limitations in mimicking human organs’ full complexity and heterogeneity (all the cell types, vasculature, and intricate organ architecture). In addition, standardization and validation protocols are still being developed.
While microfluidic technology has several advantages, there are still hurdles to overcome before it becomes a routine tool in research and clinical settings. However, with ongoing advancements and interdisciplinary efforts, these limitations can be addressed, leading to more widespread adoption of these technology systems in the future.
Although microfluidic technology and 3D bioprinting are both cutting-edge technologies with applications in both biology and medicine, a comparative analysis highlights some significant differences. Thus, microfluidic technology primarily controls and manipulates fluidic systems at the microscale, while 3D bioprinting creates three-dimensional structures composed of living cells and other biological materials. Microfluidic devices can also be made from various materials, including plastic, glass, and silicon, while 3D bioprinting typically uses hydrogels, cell suspensions, and other biocompatible materials to create the printed structures. Microfluidic devices are extremely precise and can be used to control and manipulate fluids with great precision, while 3D bioprinting is still a developing technology that requires further refinement to achieve the precision required for some applications. The scope of applicability of microfluidic technology encompasses a variety of fields, including biochemistry, cell biology, and drug discovery, while 3D bioprinting is mainly used in the fields of regenerative medicine and tissue engineering.
3.6. Role of Tumor Lung-on-Chip to Improve Cancer Therapy
OOC technology has become a promising tool for studying lung cancer. This technology involves using microfluidic devices containing tiny 3D structures that mimic human organs’ physical and functional properties. In the case of lung cancer, tumor organ chips can be used to study the behavior of lung cancer cells in a controlled and reproducible environment
[166][165]. The development of tumor lung-on-chip technology involves a microfluidic platform that recreates the complex microenvironment of a tumor in a laboratory setting. It typically involves culturing cancer cells on a chip, which contains channels or compartments that mimic the structure and function of blood vessels, extracellular matrix, and surrounding tissues. This technology allows researchers to study tumor growth, invasion, and response to various treatments in a more controlled and representative environment than traditional cell culture methods
[167][166].
For example, tumor lung-on-chip devices can be obtained using 3D printing technology such as lithography. These techniques allow for the precise and reproducible fabrication of microfluidic channels and chambers that mimic the lung structure
[168][167]. Advances in cell culture techniques, such as induced pluripotent stem cells (iPSCs), have made it possible to generate lung cells that can be used to model the human lung in vitro. These devices often incorporate sensors and imaging techniques to monitor the response of lung cells and tissues to different stimuli. For example, fluorescent imaging can track the movement of cells and molecules within the device. Also, electrical sensors can measure lung cells’ response to mechanical and chemical stimuli
[169][168].
Tumor lung-on-chip devices rely on microfluidic technology to simulate the flow of air and fluids through the lung cells. Microfluidic channels and valves are used to control the airflow and fluids through the device and ensure the study of the response of lung cells and tissues to different environmental conditions
[170][169].
Tumor lung-on-chip represents a relevant model for studying lung physiology. Until now, two models of the human lung have been created—the Alveolus Lung-Chip and the Airway Lung-Chip—which facilitate the study of pulmonary physiopathology and the drug’s effect. After loading the tumor-on-chips with the biological materials, they are connected in a module responsible for the nutrient media distribution and the control of the dose of the compound. The entire system is controlled by software that allows users to design tumor-on-chip studies, monitor the process remotely, and analyze the generated results (
Figure 6). Tumor lung-on-chip can be used to test the efficacy of new drugs and assess their toxicity in a more physiologically relevant setting. This can provide valuable information for the development of new treatments for lung cancer. In addition, using tumor lung-on-chips, the interactions between lung cancer cells and other cells and tissues in the microenvironment can be studied. This can provide essential insights into lung cancer progression mechanisms and may help identify new therapy targets. There have been several studies utilizing tumor lung-on-chip models to study lung cancer. For example, researchers have developed a tumor lung-on-chip model that recapitulates the tumor microenvironment and allows for the testing of various cancer treatments
[171][170]. This model utilizes human lung cancer cells, stromal cells, and extracellular matrix components to simulate the tumor microenvironment. It has been used to evaluate the effectiveness of different cancer drugs, including chemotherapeutic agents and targeted therapies
[172,173,174][171][172][173]. Another example is a study that developed a tumor lung-on-chip model to study the interactions between tumor cells and immune cells in the tumor microenvironment. This model allowed analysis of the dynamics with which immune cells can infiltrate the tumor site and how they can affect the growth and migration of tumor cells
[175][174]. OOC models have also been used to study the metastatic process of lung cancer, which is responsible for most lung cancer-related deaths. Researchers have developed a microfluidic model that mimics the blood vessel walls and allows for studying cancer cell invasion and migration through the endothelial barrier, creating a microfluidic platform that mimics the in vivo microenvironment of NSCL cells
[176,177,178][175][176][177]. This microchip was used to test the cytotoxic effects of the drugs erlotinib (an EGFR tyrosine kinase inhibitor) and a novel anticancer agent NSC-750212 ([1-[(chlorophenyl)methyl]indol-3-yl]methanol). A tumor lung-on-chip model was created by Yang et al.
[179][178] to test the effects of the anticancer drug—gefitinib (a tyrosine kinase inhibitor) on a co-culture of NSCL cancer cells, lung fibroblasts, and human endothelial cells. Also, using an organ tumor model, Khalid et al.
[180][179] tested the effect of doxorubicin (DOX) and docetaxel (an antimitotic drug) on the apoptosis process in lung tumors. In another experiment, using microfluidic technology, co-cultures between human lung carcinoma cells and human amniotic membrane-derived mesenchymal stem cells (AMMSC) were performed, observing how the applied therapy influences the process by the development of tumor spheroids
[181,182][180][181].
These tumor organ chip platforms can be used to develop and apply personalized therapy in different forms of cancer. Also, these devices allow the analysis of how the tumor microenvironment can influence the delivery of therapeutic agents, thus facilitating the development of more efficient drug administration systems at the tumor site
[183,184][182][183].
Tumor organ-on-chip technology can be used in lung cancer immunotherapy by providing a platform to study the interactions between tumor cells and the immune system effectors and the effects of different immunotherapeutic agents on the tumor microenvironment. Tumor organ-on-chip facilitates the evaluation of the impact of cytokine therapies, which boost the immune system’s ability to attack cancer cells, and the effects of CAR-T cell therapies, which genetically modify the patient’s immune cells to target cancer cells
[185,186][184][185]. For example, tumor organ-on-chip models can test the efficacy of checkpoint inhibitors, which block the inhibitory signals of the tumor cells used to evade the immune system. One type of immunotherapy aims to improve the immune response against cancer cells by blocking programmed cell death protein 1 (PD-1), a protein that induces inhibition of the immune system during the formation of the PD-1/PD-L1 pathway by targeting PLD1 (programmed cell death ligand1), which is involved in tumor cell growth and survival. Tumor cells are known to have the ability to escape immune surveillance and continue to proliferate. Thus, in recent years in cancer therapy, targeting PD-1 and PD-L1 has led to obtaining immune checkpoint inhibitors, such as anti-PD-1 and anti-PD-L1 antibodies, to block the interaction between PD-1 on T cells and PD-L1 on cancer cells
[187][186].
Recent studies have shown that these inhibitors may significantly increase the treatment benefit of advanced NSCLC, especially in patients with high levels of PD-L1 expression
[188][187].
The use of tumor organ-on-chip technology in the study of lung cancer offers the advantage of recreating the complex microenvironment of lung tumors, including the extracellular matrix, blood vessels, immune cells, and other components. Also, these devices ensure the simulation of the behavior of immune cells in the tumor microenvironment and allow for the study of the mechanisms of interaction between immune cells and tumor cells. Studies using tumor organ-on-chip platforms facilitate drug screening by testing the effectiveness of different immunotherapeutic agents on patient-derived tumor cells and monitoring the response in real time. The data obtained provide valuable information on the patient’s responses, offering the possibility of personalized treatment approaches. With the help of microtechnology devices, the mechanisms underlying tumor-immune cell interactions can be investigated, including the expression of immune checkpoint proteins and their role in regulating immune responses to facilitate the development of new immunotherapeutic strategies.
OOCs have an essential role in evaluating the toxicity of immunotherapies on healthy cells within the chip, providing a controlled environment to assess the safety profiles of different treatment regimens.
New 3D culture and microfluidic technology approaches are needed to improve lung cancer therapy. Thus, by developing new and more sophisticated 3D culture models, it is possible to better understand lung tumor cells’ behavior and biology, leading to improved therapeutic strategies. Using 3D culture models and microfluidic technology to study drug resistance mechanisms in lung cancer helps identify new therapeutic targets and strategies to overcome this challenge. For the created models to apply to real clinical situations, a close collaboration between clinicians and researchers from different fields (medicine, biology, biochemistry, biotechnology) is necessary to obtain better patient results. The combination of PD-1/PD-L1 inhibitors and tumor organ-on-chip is promising for advancing lung cancer therapy (Table 4). The information presented here supports the evolving role of 3D cultures in better understanding various aspects of the tumor microenvironment and its impact on tumor progression, gene and protein expression, pro-oncogenic signaling pathways, and drug resistance. Also, 3D cultures are a promising platform for developing microfluidic technology, thus ensuring more exact screening of drugs, including those used in immunotherapy, targeted drug administration, and noninvasive monitoring. These advances can lead to more effective and personalized treatments for different pathologies, a better understanding of disease mechanisms, and improved patient outcomes.
Table 4.
Potential practical applications of tumor organ-on-chip tests for improving lung cancer treatment.
Tumor-Organ-on-Chip Test |
Studied Effect |
Practical Potential Applications |
Refs. |
Testing the physiological conditions in a realistic tumor microenvironment |
Study of mechanisms of tumor development and effects of PD-1/PD-L1 blockade on immune cell function |
Simulation of physiological conditions to analyze the infiltration process of immune cells and the established interactions with tumor cells |
[189][188] |
Testing the efficacy of PD-1/PD-L1 inhibitors |
Evaluating the effects induced by combining immunotherapy with other types of drugs and identifying potential synergistic treatments |
Finding new drugs and developing more effective therapeutic strategies |
[190][189] |
Investigation of the underlying mechanisms of therapy resistance |
Understanding the mechanisms of resistance and targeting the molecules responsible for establishing resistance to a specific type of treatment |
Development of strategies to overcome the resistance to therapy |
[191,192][190][191] |
Using the patient’s cells in tumor organ-on-chip to achieve personalized testing of different treatment strategies |
Identifying the most effective PD-1/PD-L1 inhibitor may guide treatment decisions based on the specific characteristics of an individual’s tumor |
Personalized medicine |
[193][192] |