Long-term dexamethasone treatment increases the engraftment efficiency of human breast cancer cells in adult zebrafish

Zebrafish Cancer Avatars: A Translational Platform for Analyzing Tumor Heterogeneity and Predicting Patient Outcomes

The increasing number of available anti-cancer drugs presents a challenge for oncologists, who must choose the most effective treatment for the patient. Precision cancer medicine relies on matching a drug with a tumor's molecular profile to optimize the therapeutic benefit. However, current precision medicine approaches do not fully account for intra-tumoral heterogeneity. Different mutation profiles and cell behaviors within a single heterogeneous tumor can significantly impact therapy response and patient outcomes. Patient-derived avatar models recapitulate a patient's tumor in an animal or dish and provide the means to functionally assess heterogeneity's impact on drug response. Mouse xenograft and organoid avatars are well-established, but the time required to generate these models is not practical for clinical decision-making. Zebrafish are emerging as a time-efficient and cost-effective cancer avatar model. In this review, we highlight recent developments in zebrafish cancer avatar models and discuss the unique features of zebrafish that make them ideal for the interrogation of cancer heterogeneity and as part of precision cancer medicine pipelines.

Thioredoxin Reductase-1 as a Potential Biomarker in Fibroblast-Associated HCT116 Cancer Cell Progression and Dissemination in a Zebrafish Model

The tumor microenvironment, especially that of fibroblasts, strongly promotes colorectal cancer (CRC) progression. Progressive cancers usually accumulate high reactive oxygen species (ROS), leading to oxidative stress. The stress relates to the expression of thioredoxin reductase-1 (TrxR-1), which is an oxidative stress sensitivity molecule. This study aimed to investigate TrxR-1 expression as an indication of colon-fibroblast-inducing colorectal cancer progression and metastasis. We found that the high proliferative fibroblast-cultured media (FCM) contained pro-inflammatory cytokines that have a high ability to influence HCT116 and CRC cell progression, when compared with complete media (CM) as a control in terms of growth (CM = 100.00%, FCM = 165.96%), migration (CM = 32.22%, FCM = 83.07%), invasion (CM = 130 cells/field, FCM = 449 cells/field), and EMT transformation while decreasing E-cadherin expression (CM = 1.00, FCM = 0.69) and shape factor (CM = 0.94, FCM = 0.61). In addition, the overexpression of TrxR-1 is associated with cellular oxidant enchantment in FCM-treated cells. A dot plot analysis showed a strong relation between the EMT process and the overexpression of TrxR-1 in FCM-treated cells (CM = 13/100 cells, FCM = 45/100 cells). The cancer transplantation of the adult zebrafish model illustrated a significantly higher number of microtumors in FCM-treated cells (CM = 4.33 ± 1.51/HPF, FCM = 25.00 ± 13.18/HPF) disseminated in the intraperitoneal cavity with TrxR-1 positive cells. The overexpression of TrxR-1 indicated fibroblast-associated CRC progression in HCT116 cells and the zebrafish model. Therefore, TrxR-1 could be applied as a novel biomarker for colorectal cancer progression and prognostic evaluation.

Longitudinal investigation of a xenograft tumor zebrafish model using polarization-sensitive optical coherence tomography

Breast cancer is a leading cause of death in female patients worldwide. Further research is needed to get a deeper insight into the mechanisms involved in the development of this devastating disease and to find new therapy strategies. The zebrafish is an established animal model, especially in the field of oncology, which has shown to be a promising candidate for pre-clinical research and precision-based medicine. To investigate cancer growth in vivo in zebrafish, one approach is to explore xenograft tumor models. In this article, we present the investigation of a juvenile xenograft zebrafish model using a Jones matrix optical coherence tomography (JM-OCT) prototype. Immunosuppressed wild-type fish at 1-month post-fertilization were injected with human breast cancer cells and control animals with phosphate buffered saline in the tail musculature. In a longitudinal study, the scatter, polarization, and vasculature changes over time were investigated and quantified in control versus tumor injected animals. A significant decrease in birefringence and an increase in scattering signal was detected in tumor injected zebrafish in comparison to the control once. This work shows the potential of JM-OCT as a non-invasive, label-free, three-dimensional, high-resolution, and tissue-specific imaging tool in pre-clinical cancer research based on juvenile zebrafish models.

One Host-Multiple Applications: Zebrafish (Danio rerio) as Promising Model for Studying Human Cancers and Pathogenic Diseases

In recent years, zebrafish (ZF) has been increasingly applied as a model in human disease studies, with a particular focus on cancer. A number of advantages make it an attractive alternative for mice widely used so far. Due to the many advantages of zebrafish, modifications can be based on different mechanisms and the induction of human disease can take different forms depending on the research goal. Genetic manipulation, tumor transplantation, or injection of the pathogen are only a few examples of using ZF as a model. Most of the studies are conducted in order to understand the disease mechanism, monitor disease progression, test new or alternative therapies, and select the best treatment. The transplantation of cancer cells derived from patients enables the development of personalized medicine. To better mimic a patient's body environment, immune-deficient models (SCID) have been developed. A lower immune response is mostly generated by genetic manipulation but also by irradiation or dexamethasone treatment. For many studies, using SCID provides a better chance to avoid cancer cell rejection. In this review, we describe the main directions of using ZF in research, explain why and how zebrafish can be used as a model, what kind of limitations will be met and how to overcome them. We collected recent achievements in this field, indicating promising perspectives for the future.