Engineering Heterogeneous Tumor Models for Biomedical Applications

Developing 3D bioprinting for organs-on-chips

Organs-on-chips (OoCs) have significantly advanced biomedical research by precisely reconstructing human microphysiological systems with biomimetic functions. However, achieving greater structural complexity of cell cultures on-chip for enhanced biological mimicry remains a challenge. To overcome these challenges, 3D bioprinting techniques can be used in directly building complex 3D cultures on chips, facilitating the in vitro engineering of organ-level models. Herein, we review the distinctive features of OoCs, along with the technical and biological challenges associated with replicating complex organ structures. We discuss recent bioprinting innovations that simplify the fabrication of OoCs while increasing their architectural complexity, leading to breakthroughs in the field and enabling the investigation of previously inaccessible biological problems. We highlight the challenges for the development of 3D bioprinted OoCs, concluding with a perspective on future directions aimed at facilitating their clinical translation.

Lung cancer organoid-based drug evaluation models and new drug development application trends

Lung cancer is a malignant tumor with high incidence and mortality rates in both men and women worldwide. Although anticancer drugs are prescribed to treat lung cancer patients, individual responses to these drugs vary, making it crucial to identify the most suitable treatment for each patient. Therefore, it is necessary to develop an anticancer drug efficacy prediction model that can analyze drug efficacy before patient treatment and establish personalized treatment strategies. Unlike two-dimensional (2D) cultured lung cancer cells, lung cancer organoid (LCO) models have a three-dimensional (3D) structure that effectively mimics the characteristics and heterogeneity of lung cancer cells. Lung cancer patient-derived organoids (PDOs) also have the advantage of recapitulating histological and genetic characteristics similar to those of patient tissues under in vitro conditions. Due to these advantages, LCO models are utilized in various fields, including cancer research, and precision medicine, and are especially employed in various new drug development processes, such as targeted therapies and immunotherapy. LCO models demonstrate potential applications in precision medicine and new drug development research. This review discusses the various methods for implementing LCO models, LCO-based anticancer drug efficacy analysis models, and new trends in lung cancer-targeted drug development.

Detachable DNA Assembly Module to Dissect Tumor Cells Heterogeneity via RNA Pinpoint Screening

Differential RNA expression is becoming increasingly valuable in evaluating tumor heterogeneity for a better understanding of malignant tumors and guiding personalized therapy. However, traditional techniques for analyzing cellular RNA are mainly focused on determining the absolute level of RNA, which may lead to inaccuracies in understanding tumor heterogeneity, primarily due to i) the subtle differences in certain RNA types that have similar total concentrations and ii) the existence of variations in RNA expression across different samples. Herein, a detachable DNA assembly module is proposed that is capable not only of quantifying the expression level of target RNA but also of innovatively evaluating its proportion within its RNA family population through a sequential assembly and disassembly route. Using the let-7 family as an experimental model, a significant difference is discovered in let-7a proportion between normal mammary epithelial cells and breast cancer cells, a characteristic that is often missed in bulk analysis of traditional techniques. By combining concentration and proportion information, the detachable DNA assembly module demonstrates markedly higher efficiency in discerning among various types of cells compared to traditional techniques. This innovative assembly module is expected to offer a new perspective to highlight tumor heterogeneity and guide personalized therapy.

3D Multispheroid Assembly Strategies towards Tissue Engineering and Disease Modeling

Cell spheroids (esp. organoids) as 3D culture platforms are popular models for representing cell-cell and cell-extracellular matrix (ECM) interactions, bridging the gap between 2D cell cultures and natural tissues. 3D cell models with spatially organized multiple cell types are preferred for gaining comprehensive insights into tissue pathophysiology and constructing in vitro tissues and disease models because of the complexities of natural tissues. In recent years, an assembly strategy using cell spheroids (or organoids) as living building blocks has been developed to construct complex 3D tissue models with spatial organization. Here, a comprehensive overview of recent advances in multispheroid assembly studies is provided. The different mechanisms of the multispheroid assembly techniques, i.e., automated directed assembly, noncontact remote assembly, and programmed self-assembly, are introduced. The processing steps, advantages, and technical limitations of the existing methodologies are summarized. Applications of the multispheroid assembly strategies in disease modeling, drug screening, tissue engineering, and organogenesis are reviewed. Finally, this review concludes by emphasizing persistent issues and future perspectives, encouraging researchers to adopt multispheroid assembly techniques for generating advanced 3D cell models that better resemble real tissues.

The use of microphysiological systems to model metastatic cancer

Cancer is one of the leading causes of death in the 21st century, with metastasis of cancer attributing to 90% of cancer-related deaths. Therefore, to improve patient outcomes there is a need for better preclinical models to increase the success of translating oncological therapies into the clinic. Current traditional staticin vitromodels lack a perfusable network which is critical to overcome the diffusional mass transfer limit to provide a mechanism for the exchange of essential nutrients and waste removal, and increase their physiological relevance. Furthermore, these models typically lack cellular heterogeneity and key components of the immune system and tumour microenvironment. This review explores rapidly developing strategies utilising perfusable microphysiological systems (MPS) for investigating cancer cell metastasis. In this review we initially outline the mechanisms of cancer metastasis, highlighting key steps and identifying the current gaps in our understanding of the metastatic cascade, exploring MPS focused on investigating the individual steps of the metastatic cascade before detailing the latest MPS which can investigate multiple components of the cascade. This review then focuses on the factors which can affect the performance of an MPS designed for cancer applications with a final discussion summarising the challenges and future directions for the use of MPS for cancer models.