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

Zebrafish patient-derived xenograft system for predicting carboplatin resistance and metastasis of ovarian cancer

AIMS

Ovarian cancer (OC) remains a significant challenge in oncology due to high rates of drug resistance and disease relapse following standard treatment with surgery and platinum-based chemotherapy. Despite the widespread use of these treatments, no effective biomarkers currently exist to identify which patients will respond favorably to therapy. This study introduces a zebrafish patient-derived xenograft (PDX) system, capable of replicating both the carboplatin response and metastatic behavior observed in OC patients, within a rapid 3-day assay period.

METHODS

Two OC cell lines: carboplatin-sensitive (A2780) and resistant (OVCAR8) were used to assess differential responses to treatment in murine and zebrafish xenograft models. Tumor tissues from 16 OC patients were implanted into zebrafish embryos to test carboplatin responses and predict metastasis. Additionally, eight clinical OC samples were directly implanted into zebrafish embryos as part of a proof-of-concept demonstration.

RESULTS

The zebrafish xenografts accurately reflected the carboplatin sensitivity and resistance patterns seen in in vitro and murine models. The zebrafish PDX model demonstrated a 67 % success rate for implantation and a 100 % success rate for engraftment. Notably, the model effectively distinguished between metastatic and non-metastatic disease, with an area under the ROC curve (AUC) of 0.818. Furthermore, the zebrafish PDX model showed a high concordance with patient-specific responses to carboplatin.

CONCLUSIONS

This zebrafish PDX model offers a fast, accurate, and clinically relevant platform for evaluating carboplatin response and predicting metastasis in OC patients. It holds significant potential for advancing personalized medicine, allowing for more precise therapeutic outcome predictions and individualized treatment strategies.

Comprehensive multi-omics analysis of the prognostic value and immune signature of NCF2 in pan-cancer and its relationship with acute myeloid leukemia

BACKGROUND

The neutrophil cytoplasmic factor 2 (NCF2) gene encodes the p67phox protein, which has been implicated in the pathogenesis of several diseases. However, its specific role in tumorigenesis remains ambiguous. This study seeks to clarify the prognostic implications, immune profile, and therapeutic responses associated with NCF2 across different cancer types.

METHODS

We conducted a comprehensive analysis using multi-omics data to investigate tissue-specific and single-cell specific expression, pan-cancer expression patterns, epigenetic modifications, the immune microenvironment, and therapeutic responses. Our study specifically examined NCF2-associated immune signatures, molecular mechanisms, and potential therapeutic targets in acute myeloid leukemia (AML). Additionally, we performed in vitro experiments to assess how NCF2 knockdown influences cell proliferation, apoptosis, and cell cycle dynamics in AML cell lines U937 and KG-1.

RESULTS

NCF2 is dysregulated in more than two-thirds of cancer types, with elevated expression strongly correlating with poor prognosis in various cancers, including leukemia. Multifactorial Cox analysis has identified NCF2 as an independent prognostic factor for leukemia. Immunological studies have highlighted NCF2's impact on the tumor microenvironment, particularly affecting monocytes and macrophages. Furthermore, NCF2 expression closely correlates with responses to immunotherapy and chemotherapy. In vitro experiments demonstrate that NCF2 knockdown alters proliferation, apoptosis, and cell cycle dynamics of U937 cells and KG-1 cells. Notably, NCF2 is involved in regulating the differentiation of monocytes into macrophages.

CONCLUSIONS

These findings highlight NCF2 as a promising pan-cancer biomarker that significantly impacts tumor microenvironment, therapeutic response, and is critically associated with cell cycle regulation, apoptosis and macrophage transformation in AML.

Diverse Engraftment Capability of Neuroblastoma Cell Lines in Zebrafish Larvae

Xenotransplantation of neuroblastoma cells into larval zebrafish allows the characterization of their in vivo tumorigenic abilities and high-throughput treatment screening. This established preclinical model traditionally relies on microinjection into the yolk or perivitelline space, leaving the engraftment ability of cells at the hindbrain ventricle (HBV) and pericardial space (PCS), sites valuable for evaluating metastasis, angiogenesis, and the brain microenvironment, unknown. To address this gap in knowledge, Casper zebrafish at 48 h postfertilization were microinjected with approximately 200 Kelly, Be(2)-C, SK-N-AS, or SY5Y cells into either the HBV or PCS. Fish were imaged at 1, 3, and 6 days postinjection and tumor growth was monitored at each timepoint. We hypothesized that engraftment ability and location preference would be cell line dependent. Kelly and SK-N-AS cells were able to engraft at both the HBV and PCS, with a near doubling in size of tumor volume during the 6 days observation period, with cells appearing to grow better in the HBV. Be(2)-C tumors remained static while SY5Y tumors decreased in size, with almost complete loss of volume at both sites. Therefore, the capability of neuroblastoma cell engraftment in zebrafish larvae is cell line dependent with a location preference.

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.

The Role of the Neurotrophin Network in Skin Squamous Cell Cancer and the Novel Use of the Zebrafish System

Cutaneous squamous cell carcinoma (cSCC) is the second most prevalent form of skin cancer. An increasing number of cSCCs are associated with dysregulation of key molecules that control skin homeostasis. These observations have increased interest in the role of neurotrophins and their receptors in the pathogenesis of cSCC. They have been demonstrated to have a considerable impact on the aggressiveness potential of skin cancer by both in vitro and in vivo models. In this context, mouse models are classically used to dissect proliferation versus differentiation balance, but they have some limitations in terms of time, space, and costs. Recently, zebrafish models have been implemented as a new tool to obtain information regarding the invasive capacity and metastasis of neoplastic cells. By xenotransplantation technique, cSCC cells from a patient's biopsy or cell line can be successfully characterized, with or without the presence of genetic manipulation or treatments. In addition, the evaluation of the immune microenvironment contributes to potentially identifying connections and homologies with humans. In this review, we retrace the role of the neurotrophin network in healthy and pathological skin, particularly in cSCC. We review how zebrafish models can be important tools for studying cSCC development, growth, and potential treatments.

Role of CDK4 as prognostic biomarker in Soft Tissue Sarcoma and synergistic effect of its inhibition in dedifferentiated liposarcoma sequential treatment

Soft tissue sarcomas represent an heterogeneous group of rare mesenchymal tumors comprising 1% of all solid malignancies. Among them, liposarcoma is one of the most common histotypes with atypical lipomatous tumor/well differentiated liposarcoma and dedifferentiated liposarcoma (ALT/WDLPS and DDLPS) as the major sub-entities. The unavailability of predictive, prognostic and druggable biomarkers makes the management of these lesions challenging. In recent years CDK4 and its inhibitors have emerged as potential agents for these lesions especially for ALT/WDLPS and DDLPS but the results are not conclusive and need to be elucidated. This study involved 21 ALT/WDLPS and DDLPS patients. Histological analyses of MDM2 and CDK4 were carried out. Moreover, a DDLPS patient-derived cancer model was established in vitro and in vivo assessing the efficacy of palbociclib in combination and sequential treatment. Finally, in silico analyses on CDK4 expression were carried out. The results showed a higher expression of CDK4 and MDM2 in DDLPS compared to ALT/WDLPS. Moreover, no correlation between MDM2 expression and CDK4 was observed. Next, in vitro analysis of CDK4 inhibitor palbociclib showed an antagonistic effect when combined to other chemotherapeutics, while it exhibited a significant synergy when administered in sequential schedule with lenvatinib. Next, in vivo analysis on DDLPS xenotransplanted embryos assessing the efficacy and safety profile of the in vitro tested schedules confirmed the observed data. This proof-of-concept study sheds light on the natural history of ALT/WDLPS and DDLPS and provides the rationale for the clinical applicability of sequential treatment with palbociclib in the management of DDLPS.

A Simple, Rapid, and Effective Method for Tumor Xenotransplantation Analysis in Transparent Zebrafish Embryos

In vivo studies of tumor behavior are a staple of cancer research; however, the use of mice presents significant challenges in cost and time. Here, we present larval zebrafish as a transplant model that has numerous advantages over murine models, including ease of handling, low expense, and short experimental duration. Moreover, the absence of an adaptive immune system during larval stages obviates the need to generate and use immunodeficient strains. While established protocols for xenotransplantation in zebrafish embryos exist, we present here an improved method involving embryo staging for faster transfer, survival analysis, and the use of flow cytometry to assess disease burden. Embryos are staged to facilitate rapid cell injection into the yolk of the larvae and cell marking to monitor the consistency of the injected cell bolus. After injection, embryo survival analysis is assessed up to 7 days post injection (dpi). Finally, disease burden is also assessed by marking transferred cells with a fluorescent protein and analysis by flow cytometry. Flow cytometry is enabled by a standardized method of preparing cell suspensions from zebrafish embryos, which could also be used in establishing the primary culture of zebrafish cells. In summary, the procedure described here allows a more rapid assessment of the behavior of tumor cells in vivo with larger numbers of animals per study arm and in a more cost-effective manner.

A zebrafish xenotransplant model of anaplastic thyroid cancer to study tumor microenvironment and innate immune cell interactions in vivo

Anaplastic thyroid cancer (ATC) is of the most aggressive thyroid cancer. While ATC is rare, it accounts for a disproportionately high number of thyroid cancer-related deaths. Here, we developed an ATC xenotransplant model in zebrafish larvae, where we can study tumorigenesis and therapeutic response in vivo. Using both mouse (T4888M) and human (C643)-derived fluorescently labeled ATC cell lines, we show these cell lines display different engraftment rates, mass volume, proliferation, cell death, angiogenic potential, and neutrophil and macrophage recruitment and infiltration. Next, using a PIP-FUCCI reporter to track proliferation in vivo, we observed cells in each phase of the cell cycle. Additionally, we performed long-term non-invasive intravital microscopy over 48 h to understand cellular dynamics in the tumor microenvironment at the single-cell level. Lastly, we tested two drug treatments, AZD2014 and a combination therapy of dabrafenib and trametinib, to show our model could be used as an effective screening platform for new therapeutic compounds for ATC. Altogether, we show that zebrafish xenotransplants make a great model to study thyroid carcinogenesis and the tumor microenvironment, while also being a suitable model to test new therapeutics in vivo.

Non-Mammalian Models for Understanding Neurological Defects in RASopathies

RASopathies, a group of neurodevelopmental congenital disorders stemming from mutations in the RAS/MAPK pathway, present a unique opportunity to delve into the intricacies of complex neurological disorders. Afflicting approximately one in a thousand newborns, RASopathies manifest as abnormalities across multiple organ systems, with a pronounced impact on the central and peripheral nervous system. In the pursuit of understanding RASopathies' neurobiology and establishing phenotype-genotype relationships, in vivo non-mammalian models have emerged as indispensable tools. Species such as Danio rerio, Drosophila melanogaster, Caenorhabditis elegans, Xenopus species and Gallus gallus embryos have proven to be invaluable in shedding light on the intricate pathways implicated in RASopathies. Despite some inherent weaknesses, these genetic models offer distinct advantages over traditional rodent models, providing a holistic perspective on complex genetics, multi-organ involvement, and the interplay among various pathway components, offering insights into the pathophysiological aspects of mutations-driven symptoms. This review underscores the value of investigating the genetic basis of RASopathies for unraveling the underlying mechanisms contributing to broader neurological complexities. It also emphasizes the pivotal role of non-mammalian models in serving as a crucial preliminary step for the development of innovative therapeutic strategies.

Zebrafish-A Suitable Model for Rapid Translation of Effective Therapies for Pediatric Cancers

Pediatric cancers are the leading cause of disease-related deaths in children and adolescents. Most of these tumors are difficult to treat and have poor overall survival. Concerns have also been raised about drug toxicity and long-term detrimental side effects of therapies. In this review, we discuss the advantages and unique attributes of zebrafish as pediatric cancer models and their importance in targeted drug discovery and toxicity assays. We have also placed a special focus on zebrafish models of pediatric brain cancers-the most common and difficult solid tumor to treat.

Zebrafish tumour xenograft models: a prognostic approach to epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is the gynaecological malignancy with highest mortality. Although adjuvant treatment with carboplatin and paclitaxel leads to an objective response in ~80% of these patients, a majority will relapse within two years. Better methods for assessing long-term treatment outcomes are needed. To address this, we established safe and efficacious doses of carboplatin and paclitaxel using IGROV-1 zebrafish-CDX models. Then fluorescently-labelled cell suspensions from 83 tumour biopsies collected at exploratory laparotomy of women with suspected EOC were generated and 37 (45%) were successfully implanted in zebrafish larvae. Among these 19 of 27 pathology-confirmed EOC samples (70%) engrafted. These zebrafish patient-derived tumour xenograft (ZTX) models were treated with carboplatin or paclitaxel and tumour growth/regression and metastatic dissemination were recorded. In a subgroup of nine patients, four ZTX models regressed during carboplatin treatment. All four corresponding patients had >24 months PFS. Furthermore, both ZTX models established from two patients having <24 months PFS failed to regress during carboplatin treatment. Seven of eight models seeding <6 metastatic cells were established from patients having >24 months PFS. In eleven of fourteen patients, FIGO stage I + II or III tumours gave rise to ZTX models seeding <4 or >4 metastatic cells, respectively. In conclusion, ZTX models predicted patients having >24 or <24 months PFS, based on response/no response to carboplatin. Furthermore, high metastatic dissemination in ZTX models correlated to shorter PFS and more advanced disease at diagnosis. These preliminary results suggest that ZTX models could become a useful prognostic tool in EOC treatment planning.

Zebrafish as a robust preclinical platform for screening plant-derived drugs with anticonvulsant properties-a review

Traditionally, selected plant sources have been explored for medicines to treat convulsions. This continues today, especially in countries with low-income rates and poor medical systems. However, in the low-income countries, plant extracts and isolated drugs are in high demand due to their good safety profiles. Preclinical studies on animal models of seizures/epilepsy have revealed the anticonvulsant and/or antiepileptogenic properties of, at least some, herb preparations or plant metabolites. Still, there is a significant number of plants known in traditional medicine that exert anticonvulsant activity but have not been evaluated on animal models. Zebrafish is recognized as a suitable in vivo model of epilepsy research and is increasingly used as a screening platform. In this review, the results of selected preclinical studies are summarized to provide credible information for the future development of effective screening methods for plant-derived antiseizure/antiepileptic therapeutics using zebrafish models. We compared zebrafish vs. rodent data to show the translational value of the former in epilepsy research. We also surveyed caveats in methodology. Finally, we proposed a pipeline for screening new anticonvulsant plant-derived drugs in zebrafish ("from tank to bedside and back again").

Application of Zebrafish as a Model for Anti-Cancer Activity Evaluation and Toxicity Testing of Natural Products

Developing natural product-based anti-cancer drugs/agents is a promising way to overcome the serious side effects and toxicity of traditional chemotherapeutics for cancer treatment. However, rapid assessment of the in vivo anti-cancer activities of natural products is a challenge. Alternatively, zebrafish are useful model organisms and perform well in addressing this challenging issue. Nowadays, a growing number of studies have utilized zebrafish models to evaluate the in vivo activities of natural compounds. Herein, we reviewed the application of zebrafish models for evaluating the anti-cancer activity and toxicity of natural products over the past years, summarized its process and benefits, and provided future outlooks for the development of natural product-based anti-cancer drugs.

Zebrafish: A Relevant Genetic Model for Human Primary Immunodeficiency (PID) Disorders?

Primary immunodeficiency (PID) disorders, also commonly referred to as inborn errors of immunity, are a heterogenous group of human genetic diseases characterized by defects in immune cell development and/or function. Since these disorders are generally uncommon and occur on a variable background profile of potential genetic and environmental modifiers, animal models are critical to provide mechanistic insights as well as to create platforms to underpin therapeutic development. This review aims to review the relevance of zebrafish as an alternative genetic model for PIDs. It provides an overview of the conservation of the zebrafish immune system and details specific examples of zebrafish models for a multitude of specific human PIDs across a range of distinct categories, including severe combined immunodeficiency (SCID), combined immunodeficiency (CID), multi-system immunodeficiency, autoinflammatory disorders, neutropenia and defects in leucocyte mobility and respiratory burst. It also describes some of the diverse applications of these models, particularly in the fields of microbiology, immunology, regenerative biology and oncology.