A novel 3D pillar/well array platform using patient-derived head and neck tumor to predict the individual radioresponse

Improving therapeutic strategies for Head and Neck Cancer: Insights from 3D hypoxic cell culture models in treatment response evaluation

Hypoxia in the tumor core negatively affects the outcome of patients with head and neck squamous cell carcinoma (HNSCC). Nevertheless, its role in predicting treatment response requires further exploration. Typically, reduced oxygen levels in the tumor core correlate with diminished efficacy of radiotherapy, chemotherapy, and immunotherapy, which are commonly used for HNSCC patients' treatment. Understanding the mechanistic underpinnings of these varied treatment responses in HNSCC is crucial for enhancing therapeutic outcomes and extending patients' overall survival (OS) rates. Standard monolayer cell culture conditions have major limitations in mimicking tumor physiological features and the complexity of the tumor microenvironment. Three-dimensional (3D) cell cultures enable the recreation of the in vivo tumor attributes, encompassing oxygen and nutrient gradients, cellular morphology, and intracellular connections. It is vital to use the 3D model in treatment response studies to mimic the tumor microenvironment, as evidenced by the decreased sensitivity of 3D structures to anticancer therapy. Accordingly, the aim of the study was to delineate the utility of the 3D models of hypoxic head and neck tumors in drug screening and treatment response studies.

A simple and rapid assay of lysosomal-targeting CDy6 for long-term real-time viability assessments in 2D and 3D in vitro culture models

CDy6, a BODIPY-derived compound, is used to label lysosomes and visualize proliferating cells. However, its effectiveness in long-term, real-time cell viability assays using 2D or 3D cell culture models is unclear. We evaluated the suitability of CDy6 by assessing cell health using human keratinocyte and fibroblast cell lines in both models. Cells were stained with CDy6 or other dyes and fluorescent images were obtained with confocal microscopy. CLV extracts derived from CDy6-stained HaCaT cells were also dissolved with DMSO and analyzed using a spectrometer. Furthermore, we added CDy6-stained collagen hydrogels to CCD-986sk cells, loaded them into a frame construction to establish a 3D dermal layer for long-term culture, and analyzed the status of the CLVs. The CLV method, also measured using a spectrometer, yielded results similar to MTT assay for validating viability. In contrast to calcein AM staining, the CLV method allows for both absorbance measurement and imaging under short-term and long-term culture conditions with less cytotoxicity. In conclusion, the CLV method provides a simple and sensitive tool for assessing the status of live cells in 2D and 3D in vitro cell culture models and can be used as an alternative to animal testing, such as with 3D artificial skin models.

Emerging roles of 3D-culture systems in tackling tumor drug resistance

Drug resistance that affects patients universally is a major challenge in cancer therapy. The development of drug resistance in cancer cells is a multifactor event, and its process involves numerous mechanisms that allow these cells to evade the effect of treatments. As a result, the need to understand the molecular mechanisms underlying cancer drug sensitivity is imperative. Traditional 2D cell culture systems have been utilized to study drug resistance, but they often fail to mimic the 3D milieu and the architecture of real tissues and cell-cell interactions. As a result of this, 3D cell culture systems are now considered a comprehensive model to study drug resistance in vitro. Cancer cells exhibit an in vivo behavior when grown in a three-dimensional environment and react to therapy more physiologically. In this review, we discuss the relevance of main 3D culture systems in the study of potential approaches to overcome drug resistance and in the identification of personalized drug targets with the aim of developing patient-specific treatment strategies that can be put in place when resistance emerges.

Clonal evolution of long-term expanding head and neck cancer organoid: Impact on treatment response for personalized therapeutic screening

OBJECTIVES

In biobanking based on patient-derived organoids (PDO), the genetic stability of organoid lines is critical for the clinical relevance of PDO with parental tumors. However, data on mutational heterogeneity and clonal evolution of PDO and their effects on treatment response are insufficient.

METHODS

To investigate whether head and neck cancer organoids (HNCOs) could maintain the genetic characteristics of their original tumors and elucidate the clonal evolution process during a long-term passage, we performed targeted sequencing, covering 377 cancer-related genes and adopted a sub-clonal fraction model. To explore therapeutic response variability between an early and late passage (>passage 6), we generated dose-response curves for drugs and radiation using two HNCO lines.

RESULTS

Using 3D ex vivo organoid culture protocol, we successfully established 27 HNCOs from 39 patients with an overall success rate of 70% (27/39). Their mutational profiles were highly concordant, with three of the HNCOs analyzed showing greater than 70% concordance. Only one HNCO displayed less than 50% concordance. However, many of these organoid lines displayed clonal evolution during serial passaging, although major cancer driver genes and VAF distributions were shared between early and later passages. We also found that all late passages of HNCOs tended to be more sensitive to radiation than early passages, similar to drug response results.

CONCLUSIONS

We report the establishment of HNCO lines derived from 27 patients and demonstrate their genetic concordance with corresponding parental tumors. Furthermore, we show serial changes in mutational profiles of HNCO along with long passage culture and the impact of these clonal evolutions on response to radiotherapy.

In Vitro Three-dimensional (3D) Cell Culture Tools for Spheroid and Organoid Models

Three-dimensional (3D) cell culture technology has been steadily studied since the 1990's due to its superior biocompatibility compared to the conventional two-dimensional (2D) cell culture technology, and has recently developed into an organoid culture technology that further improved biocompatibility. Since the 3D culture of human cell lines in artificial scaffolds was demonstrated in the early 90's, 3D cell culture technology has been actively developed owing to various needs in the areas of disease research, precision medicine, new drug development, and some of these technologies have been commercialized. In particular, 3D cell culture technology is actively being applied and utilized in drug development and cancer-related precision medicine research. Drug development is a long and expensive process that involves multiple steps-from target identification to lead discovery and optimization, preclinical studies, and clinical trials for approval for clinical use. Cancer ranks first among life-threatening diseases owing to intra-tumoral heterogeneity associated with metastasis, recurrence, and treatment resistance, ultimately contributing to treatment failure and adverse prognoses. Therefore, there is an urgent need for the development of efficient drugs using 3D cell culture techniques that can closely mimic in vivo cellular environments and customized tumor models that faithfully represent the tumor heterogeneity of individual patients. This review discusses 3D cell culture technology focusing on research trends, commercialization status, and expected effects developed until recently. We aim to summarize the great potential of 3D cell culture technology and contribute to expanding the base of this technology.

An Automated High-Throughput Screening (HTS) Spotter for 3D Tumor Spheroid Formation

Three-dimensional (3D) culture platforms have been adopted in a high-throughput screening (HTS) system to mimic in vivo physiological microenvironments. The automated dispenser has been established commercially to enable spotting or distributing non-viscous or viscous biomaterials onto microplates. However, there are still challenges to the precise and accurate dispensation of cells embedded in hydrogels such as Alginate- and Matrigel-extracellular matrices. We developed and improved an automated contact-free dispensing machine, the ASFA SPOTTER (V5 and V6), which is compatible with 96- and 384-pillar/well plates and 330- and 532-micropillar/well chips for the support of 3D spheroid/organoid models using bioprinting techniques. This enables the distribution of non-viscous and viscous biosamples, including chemical drugs and cancer cells, for large-scale drug screening at high speed and small volumes (20 to 4000 nanoliters) with no damage to cells. The ASFA SPOTTER (V5 and V6) utilizes a contact-free method that minimizes cross-contamination for the dispensation of encapsulated tissue cells with highly viscous scaffolds (over 70%). In particular, the SPOTTER V6 does not require a washing process and offers the advantage of almost no dead volume (defined as additional required sample volume, including a pre-shot and flushing shot for dispensing). It can be successfully applied for the achievement of an organoid culture in automation, with rapid and easy operation, as well as miniaturization for high-throughput screening. In this study, we report the advantages of the ASFA SPOTTER, which distributes standard-sized cell spots with hydrogels onto a 384-pillar/well plate with a fast dispensing speed, small-scale volume, accuracy, and precision.