Automated Analysis of Extracellular Matrix Invasion of Cancer Cells from Tumor Spheroids

The main cause of mortality among cancer patients is metastatic disease. Metastasis develops from cancer cells that invade the stromal tissue and intravasate the circulatory or lymphatic systems to eventually form new tumors in other organs. Blocking cancer cell invasion can potentially prevent or reduce the metastatic progression of cancers. Testing different chemical compounds against cell invasion in three-dimensional cultures is a common laboratory technique. The efficacy of the treatments is often evaluated from confocal microscopic images of the cells using image processing. However, the analysis approaches are often subject to variations and inconsistencies due to user decisions that must be made while processing each image. To overcome this limitation, we developed a fully automated method to quantify the invasion of cancer cells from a 3D tumor spheroid into the surrounding extracellular matrix. We demonstrated that this method resolves cell invasion from spheroids of different shapes and sizes and from cells that invade as a cluster or individually. We also showed that this approach can help quantify the dose-dependent anti-invasive effects of a commonly used chemotherapy drug. Our automated method significantly reduces the time and increases the consistency and accuracy of cancer cell invasion analysis in three-dimensional cultures.

[3D tumor spheroids promote activation, expansion, and anti-tumor effects of tumor-infiltrating lymphocytes in vitro]

The adoptive immunotherapy mediated by tumor-infiltrating lymphocytes (TILs) has shown definite efficacy against various solid tumors. However, the inefficiency of the conventional method based on in vitro expansion of TILs fails to achieve the cell count and high tumor-killing activity required for therapeutic purposes. This study investigated the effect of 3D tumor spheroids on the activation and expansion of TILs in vitro, aiming to provide a novel approach for the expansion of TILs. We procured TILs and primary tumor cells from surgical samples of lung cancer patients and then compared the impacts of lung cancer cell line NCI-H1975 and primary lung cancer cells cultured under 2D and 3D conditions on the activation, expansion, and anti-tumor activity of TILs. Furthermore, we added the programmed cell death protein 1 (PD-1) antibody into the co-culture of primary tumor cells and TILs within a 3D environment to assess the effects of the antibody on TILs. The results showed that compared with 2D cultured tumor cells, the 3D cultured H1975 cells significantly enhanced the expansion of TILs, increasing the proportion of CD3+/CD8+ cells in TILs to 61.6%. The 3D primary tumor model also enhanced the proportion of CD3+/CD8+ cells in TILs (45.5%, 54.4%), induced apoptosis of tumor epithelial cells and decreased the overall tumor cells survival rate (16.7%) after co-culture. PD-1 antibodies further improved the in vitro expansion capacity of TILs mediated by 3D tumor spheroids, resulting in the proportions of 50.9% and 57.0% for CD3+/CD8+ cells and enhancing the antitumor activity significantly (reducing the overall tumor survival rate to 9.36%). In summary, the use of 3D tumor spheroids significantly promoted the expansion and improved the anti-tumor effect of TILs, and the use of the PD-1 antibody further promoted the expansion and tumor-killing effect of TILs.

Recent advances in 3D bioprinting for cancer research: From precision models to personalized therapies

Cancer remains one of the most devastating diseases, necessitating innovative and precise therapeutic solutions. The emergence of 3D bioprinting has revolutionized the platform of cancer therapy by offering bespoke solutions for drug screening, tumor modeling, and personalized medicine. The utilization of 3D bioprinting enables the fabrication of complex tumor models that closely mimic the in vivo microenvironment, facilitating more accurate drug testing and personalized treatment strategies. Moreover, 3D bioprinting also provides a platform for the development of implantable scaffolds as a therapeutic solution to cancer. In this review, we highlight the application of 3D bioprinting for cancer therapy along with current advancements in cancer 3D model development with recent case studies.

Satellite-Based On-Orbit Printing of 3D Tumor Models

Space three dimension (3D） bioprinting provides a precise and bionic tumor model for evaluating the compound effect of the space environment on tumors, thereby providing insight into the progress of the disease and potential treatments. However, space 3D bioprinting faces several challenges, including prelaunch uncertainty, possible liquid leakage, long-term culture in space, automatic equipment control, data acquisition, and transmission. Here, a novel satellite-based 3D bioprinting device with high structural strength, small volume, and low weight (<6 kg) is developed. A microgel-based biphasic thermosensitive bioink and suspension medium that supports the on-orbit printing and in situ culture of complex tumor models is developed. An intelligent control algorithm that enables the automatic control of 3D printing, autofocusing, fluorescence imaging, and data transfer back to the ground is developed. To the authors' knowledge, this is the first time that on-orbit printing of tumor models is achieved in space with stable morphology and moderate viability via a satellite. It is found that 3D tumor models are more sensitive to antitumor drugs in space than on Earth. This study opens up a new avenue for 3D bioprinting in space and offers new possibilities for future research in space life science and medicine.

Single-cell sequencing of tumor-associated macrophages in a Drosophila model

Introduction

Tumor-associated macrophages may act to either limit or promote tumor growth, yet the molecular basis for either path is poorly characterized.

Methods

We use a larval Drosophila model that expresses a dominant-active version of the Ras-oncogene (RasV12) to study dysplastic growth during early tumor progression. We performed single-cell RNA-sequencing of macrophage-like hemocytes to characterize these cells in tumor- compared to wild-type larvae. Hemocytes included manually extracted tumor-associated- and circulating cells.

Results and discussion

We identified five distinct hemocyte clusters. In addition to RasV12 larvae, we included a tumor model where the activation of effector caspases was inhibited, mimicking an apoptosis-resistant setting. Circulating hemocytes from both tumor models differ qualitatively from control wild-type cells-they display an enrichment for genes involved in cell division, which was confirmed using proliferation assays. Split analysis of the tumor models further reveals that proliferation is strongest in the caspase-deficient setting. Similarly, depending on the tumor model, hemocytes that attach to tumors activate different sets of immune effectors-antimicrobial peptides dominate the response against the tumor alone, while caspase inhibition induces a shift toward members of proteolytic cascades. Finally, we provide evidence for transcript transfer between hemocytes and possibly other tissues. Taken together, our data support the usefulness of Drosophila to study the response against tumors at the organismic level.

Bacteria-based immunotherapy for cancer: a systematic review of preclinical studies

Immunotherapy has been emerging as a powerful strategy for cancer management. Recently, accumulating evidence has demonstrated that bacteria-based immunotherapy including naive bacteria, bacterial components, and bacterial derivatives, can modulate immune response via various cellular and molecular pathways. The key mechanisms of bacterial antitumor immunity include inducing immune cells to kill tumor cells directly or reverse the immunosuppressive microenvironment. Currently, bacterial antigens synthesized as vaccine candidates by bioengineering technology are novel antitumor immunotherapy. Especially the combination therapy of bacterial vaccine with conventional therapies may further achieve enhanced therapeutic benefits against cancers. However, the clinical translation of bacteria-based immunotherapy is limited for biosafety concerns and non-uniform production standards. In this review, we aim to summarize immunotherapy strategies based on advanced bacterial therapeutics and discuss their potential for cancer management, we will also propose approaches for optimizing bacteria-based immunotherapy for facilitating clinical translation.

Tumor organoid model of colorectal cancer (Review)

The establishment of self-organizing 'mini-gut' organoid models has brought about a significant breakthrough in biomedical research. Patient-derived tumor organoids have emerged as valuable tools for preclinical studies, offering the retention of genetic and phenotypic characteristics of the original tumor. These organoids have applications in various research areas, including in vitro modelling, drug discovery and personalized medicine. The present review provided an overview of intestinal organoids, focusing on their unique characteristics and current understanding. The progress made in colorectal cancer (CRC) organoid models was then delved into, discussing their role in drug development and personalized medicine. For instance, it has been indicated that patient-derived tumor organoids are able to predict response to irinotecan-based neoadjuvant chemoradiotherapy. Furthermore, the limitations and challenges associated with current CRC organoid models were addressed, along with proposed strategies for enhancing their utility in future basic and translational research.

A perfused multi-well bioreactor platform to assess tumor organoid response to a chemotherapeutic gradient

There is an urgent need to develop new therapies for colorectal cancer that has metastasized to the liver and, more fundamentally, to develop improved preclinical platforms of colorectal cancer liver metastases (CRCLM) to screen therapies for efficacy. To this end, we developed a multi-well perfusable bioreactor capable of monitoring CRCLM patient-derived organoid response to a chemotherapeutic gradient. CRCLM patient-derived organoids were cultured in the multi-well bioreactor for 7 days and the subsequently established gradient in 5-fluorouracil (5-FU) concentration resulted in a lower IC₅₀ in the region near the perfusion channel versus the region far from the channel. We compared behaviour of organoids in this platform to two commonly used PDO culture models: organoids in media and organoids in a static (no perfusion) hydrogel. The bioreactor IC₅₀ values were significantly higher than IC₅₀ values for organoids cultured in media whereas only the IC₅₀ for organoids far from the channel were significantly different than organoids cultured in the static hydrogel condition. Using finite element simulations, we showed that the total dose delivered, calculated using area under the curve (AUC) was similar between platforms, however normalized viability was lower for the organoid in media condition than in the static gel and bioreactor. Our results highlight the utility of our multi-well bioreactor for studying organoid response to chemical gradients and demonstrate that comparing drug response across these different platforms is nontrivial.

Evaluation of the Effect of Fibroblasts on Melanoma Metastasis Using a Biomimetic Co-Culture Model

Melanoma is a highly malignant tumor originating from melanocytes. The 5-year survival rate of primary melanoma is 98%, whereas the survival rate of metastatic melanoma is only 10%, which can be attributed to the insensitivity to existing treatments. Fibroblasts are the primary cells in the dermis that promote melanoma metastasis; however, the molecular mechanism underlying the fibroblast-melanoma interaction is yet to be completely understood. Herein, gelatin methacryloyl (GelMA) was used to construct a co-culture model for melanoma cells (A375) and fibroblasts. GelMA retains the good biological properties of collagen, which has been identified as the primary component of the melanoma tumor microenvironment. Fibroblasts were encapsulated in GelMA, whereas A375 cells were cultured on the GelMA surface, which realistically mimics the macrostructure of melanoma. A375 cells co-cultured with fibroblasts demonstrated a higher cellular proliferation rate, potentials of neoneurogenesis, overexpression of epithelial mesenchymal transition markers, and a faster migration rate compared with A375 cells cultured alone, which could be due to the cancer-associated fibroblast activation and the overexpression of transforming growth factor β1 and fibroblast growth factor-2 by fibroblasts. Overall, this study revealed the possible mechanisms of fibroblast-melanoma interaction and suggested that this co-culture model could be potentially further developed as a platform for screening chemotherapies in the future.

3D bioprinted osteosarcoma model for experimental boron neutron capture therapy (BNCT) applications: Preliminary assessment

Osteosarcoma is the most frequently primary malignant bone tumor characterized by infiltrative growth responsible for relapses and metastases. Treatment options are limited, and a new therapeutic option is required. Boron neutron capture therapy (BNCT) is an experimental alternative radiotherapy able to kill infiltrative tumor cells spearing surrounding healthy tissues. BNCT studies are performed on 2D in vitro models that are not able to reproduce pathological tumor tissue organization or on in vivo animal models that are expensive, time-consuming and must follow the 3R's principles. A 3D in vitro model is a solution to better recapitulate the complexity of solid tumors meanwhile limiting the animal's use. Objective of this study is to optimize the technical assessment for developing a 3D in vitro osteosarcoma model as a platform for BNCT studies: printing protocol, biomaterial selection, cell density, and crosslinking process. The best parameters that allow a fully colonized 3D bioprinted construct by rat osteosarcoma cell line UMR-106 are 6 × 10⁶ cells/ml of hydrogel and 1% CaCl₂ as a crosslinking agent. The proposed model could be an alternative or a parallel approach to 2D in vitro culture and in vivo animal models for BNCT experimental study.

Syrian hamster as an ideal animal model for evaluation of cancer immunotherapy

Cancer immunotherapy (CIT) has emerged as an exciting new pillar of cancer treatment. Although benefits have been achieved in individual patients, the overall response rate is still not satisfactory. To address this, an ideal preclinical animal model for evaluating CIT is urgently needed. Syrian hamsters present similar features to humans with regard to their anatomy, physiology, and pathology. Notably, the histological features and pathological progression of tumors and the complexity of the tumor microenvironment are equivalent to the human scenario. This article reviews the current tumor models in Syrian hamster and the latest progress in their application to development of tumor treatments including immune checkpoint inhibitors, cytokines, adoptive cell therapy, cancer vaccines, and oncolytic viruses. This progress strongly advocates Syrian hamster as an ideal animal model for development and assessment of CIT for human cancer treatments. Additionally, the challenges of the Syrian hamster as an animal model for CIT are also discussed.

Evaluation of CAR-T Cells' Cytotoxicity against Modified Solid Tumor Cell Lines

In recent years, adoptive cell therapy has gained a new perspective of application due to the development of technologies and the successful clinical use of CAR-T cells for the treatment of patients with malignant B-cell neoplasms. However, the efficacy of CAR-T therapy against solid tumor remains a major scientific and clinical challenge. In this work, we evaluated the cytotoxicity of 2nd generation CAR-T cells against modified solid tumors cell lines-lung adenocarcinoma cell line H522, prostate carcinoma PC-3M, breast carcinoma MDA-MB-231, and epidermoid carcinoma A431 cell lines transduced with lentiviruses encoding red fluorescent protein Katushka2S and the CD19 antigen. A correlation was demonstrated between an increase in the secretion of proinflammatory cytokines and a decrease in the confluence of tumor cells' monolayer. The proposed approach can potentially be applied to preliminarily assess CAR-T cell efficacy for the treatment of solid tumors and estimate the risks of developing cytokine release syndrome.

Hierarchical Vessel Network-Supported Tumor Model-on-a-Chip Constructed by Induced Spontaneous Anastomosis

The vascular system in living tissues is a highly organized system that consists of vessels with various diameters for nutrient delivery and waste transport. In recent years, many vessel construction methods have been developed for building vascularized on-chip tissue models. These methods usually focused on constructing vessels at a single scale. In this work, a method that can build a hierarchical and perfusable vessel networks was developed. By providing flow stimuli and proper HUVEC concentration, spontaneous anastomosis between endothelialized lumens and the self-assembled capillary network was induced; thus, a perfusable network containing vessels at different scales was achieved. With this simple method, an in vivo-like hierarchical vessel-supported tumor model was prepared and its application in anticancer drug testing was demonstrated. The tumor growth rate was predicted by combining computational fluid dynamics simulation and a tumor growth mathematical model to understand the vessel perfusability effect on tumor growth rate in the hierarchical vessel network. Compared to the tumor model without capillary vessels, the hierarchical vessel-supported tumor shows a significantly higher growth rate and drug delivery efficiency.

3D-printed Model and guide plate for accurate resection of advanced cutaneous squamous cell carcinomas

Purpose

Advanced cutaneous squamous cell carcinomas (cSCC) can have unclear borders, and simple expanded resection may not only destroy surrounding normal tissues unnecessarily, but can also leave residual tumor cells behind. In this article, we describe a new method for resection and evaluate its accuracy.

Methods

The magnetic resonance imaging (MRI) data of 12 patients with advanced cSCC were reconstructed to obtain three-dimensional (3D) tumor models and guide plates for surgeries. Thirty-eight patients with the same cSCC stage, who underwent expanded resection, were included. The distances between the upper, lower, left and right horizontal margins and tumor pathological boundaries were classified as "positive", "close" (0-6 mm), "adequate" (6-12 mm) or "excessive" (>12 mm). The positive margin rate and margin distance were compared between the groups.

Results

The 3D tumor models of 12 patients were all successfully reconstructed. The positive rate of 48 surgical margins in the guide plate group was 2.1%, and the proportion of "adequate" margins was 70.8%. A total of 152 margins of 38 patients were included in the extended resection group, for which the positive rate was 13.8%; this was higher than that of the guide plate group (P = 0.045). The proportion of "adequate" margins was 27.6%, with group differences seen in the distance distribution (P < 0.01).

Conclusions

In surgical resection of advanced cSCC, compared with simple expanded resection, surgical planning using a 3D tumor model and guide plate can reduce the rate of horizontal surgical margins, and the probability of under- or over-resection.Clinical Trial Registration: http://www.chictr.org.cn, Identifier [No. ChiCTR2100050174].

Progresses, Challenges, and Prospects of CRISPR/Cas9 Gene-Editing in Glioma Studies

Glioma refers to a tumor that is derived from brain glial stem cells or progenitor cells and is the most common primary intracranial tumor. Due to its complex cellular components, as well as the aggressiveness and specificity of the pathogenic site of glioma, most patients with malignant glioma have poor prognoses following surgeries, radiotherapies, and chemotherapies. In recent years, an increasing amount of research has focused on the use of CRISPR/Cas9 gene-editing technology in the treatment of glioma. As an emerging gene-editing technology, CRISPR/Cas9 utilizes the expression of certain functional proteins to repair tissues or treat gene-deficient diseases and could be applied to immunotherapies through the expression of antigens, antibodies, or receptors. In addition, some research also utilized CRISPR/Cas9 to establish tumor models so as to study tumor pathogenesis and screen tumor prognostic targets. This paper mainly discusses the roles of CRISPR/Cas9 in the treatment of glioma patients, the exploration of the pathogenesis of neuroglioma, and the screening targets for clinical prognosis. This paper also raises the future research prospects of CRISPR/Cas9 in glioma, as well as the opportunities and challenges that it will face in clinical treatment in the future.

Recent advances of three-dimensional bioprinting technology in hepato-pancreato-biliary cancer models

Hepato-pancreato-biliary (HPB) cancer is a serious category of cancer including tumors originating in the liver, pancreas, gallbladder and biliary ducts. It is limited by two-dimensional (2D) cell culture models for studying its complicated tumor microenvironment including diverse contents and dynamic nature. Recently developed three-dimensional (3D) bioprinting is a state-of-the-art technology for fabrication of biological constructs through layer-by-layer deposition of bioinks in a spatially defined manner, which is computer-aided and designed to generate viable 3D constructs. 3D bioprinting has the potential to more closely recapitulate the tumor microenvironment, dynamic and complex cell-cell and cell-matrix interactions compared to the current methods, which benefits from its precise definition of positioning of various cell types and perfusing network in a high-throughput manner. In this review, we introduce and compare multiple types of 3D bioprinting methodologies for HPB cancer and other digestive tumors. We discuss the progress and application of 3D bioprinting in HPB and gastrointestinal cancers, focusing on tumor model manufacturing. We also highlight the current challenges regarding clinical translation of 3D bioprinting and bioinks in the field of digestive tumor research. Finally, we suggest valuable perspectives for this advanced technology, including combination of 3D bioprinting with microfluidics and application of 3D bioprinting in the field of tumor immunology.

Direct and indirect damage zone of radiofrequency ablation in porcine lumbar vertebra

Objectives

To explore the direct and indirect heat damage zone of radiofrequency ablation (RFA) in porcine vertebrae and to verify the safety of RFA in a vascularized vertebral tumor model.

Methods

RFA was performed in the porcine lumbar vertebrae. Magnetic resonance (MR) imaging, hematoxylin and eosin (HE), and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) were used to assess the extent of direct and indirect injuries after RFA. The cavity of lumbar vertebrae was made, and the adjacent muscle flap was used to fill the cavity to make a vertebrae tumor model. RFA was performed in the vascularized vertebral tumor model.

Results

T1-weighted images showed a hypointensive region in the center surrounded by a more hypointensive rim on day 0 and 14. T2-weighted images showed that RFA zone was hypointensive on day 0. On day 7, hypointensity was detected in the center surrounded by a hyperintensive rim. HE showed that the RFA zone could be clearly observed on day 14. Thin bone marrow loss areas were seen around the RFA zone, which was consistent with the hyperintensive rim on the T2-weighted images. TUNEL showed a large number of apoptotic cells in the RFA zone. During RFA in the vertebral tumor model, the temperature of all monitoring positions was less than 45 °C.

Conclusion

Using in vivo experiments, the effective zone of RFA was evaluated by MR imaging and pathology, and the direct and indirect damage range were obtained. The safety of RFA was verified by RFA in a vascularized vertebral tumor model.

Tumor-on-a-chip: Perfusable vascular incorporation brings new approach to tumor metastasis research and drug development

The extracellular matrix interacts with cancer cells and is a key factor in the development of cancer. Traditional two-dimensional models cannot mimic the natural in situ environment of cancer tissues, whereas three-dimensional (3D) models such as spherical culture, bioprinting, and microfluidic approaches can achieve in vitro reproduction of certain structures and components of the tumor microenvironment, including simulation of the hypoxic environment of tumor tissue. However, the lack of a perfusable vascular network is a limitation of most 3D models. Solid tumor growth and metastasis require angiogenesis, and tumor models with microvascular networks have been developed to better understand underlying mechanisms. Tumor-on-a-chip technology combines the advantages of microfluidics and 3D cell culture technology for the simulation of tumor tissue complexity and characteristics. In this review, we summarize progress in constructing tumor-on-a-chip models with efficiently perfused vascular networks. We also discuss the applications of tumor-on-a-chip technology to studying the tumor microenvironment and drug development. Finally, we describe the creation of several common tumor models based on this technology to provide a deeper understanding and new insights into the design of vascularized cancer models. We believe that the tumor-on-a-chip approach is an important development that will provide further contributions to the field.

Tumor vascular heterogeneity and the impact of subtumoral nanoemulsion biodistribution

Aim: Investigate the heterogeneous tumor tissue organization and examine how this condition can interfere with the passive delivery of a lipid nanoemulsion in two breast cancer preclinical models (4T1 and Ehrlich). Materials & methods: The authors used in vivo image techniques to follow the nanoemulsion biodistribution and microtomography, as well as traditional histopathology and electron microscopy to evaluate the tumor structural characteristics. Results & conclusion: Lipid nanoemulsion was delivered to the tumor, vascular organization depends upon the subtumoral localization and this heterogeneous organization promotes a nanoemulsion biodistribution to the highly vascular peripherical region. Also, the results are presented with a comprehensive mathematical model, describing the differential biodistribution in two different breast cancer models, the 4T1 and Ehrlich models.

Chemokine Homeostasis in Healthy Volunteers and during Pancreatic and Colorectal Tumor Growth in Murine Models

Chemokines are involved in the humoral regulation of body homeostasis. Changes in the blood level of chemokines were found in cancer, atherosclerosis, diabetes, and other systemic diseases. It is essential to distinguish the effects of co-morbid pathologies and cancer on the level of chemokines in the blood. We aimed to analyze, by multiplex cytometry, the levels of chemokines in the blood of healthy young volunteers as well as of intact mice and mice with CT26 colon and Pan02 pancreatic tumors. Two types of chemokines were identified both in human and murine plasmas: homeostatic ones, which were found in high concentrations (>100 pg/mL), and inducible ones, which can be undetectable or determined at very low levels (0−100 pg/mL). There was a high variability in the chemokine levels, both in healthy humans and mice. To analyze chemokine levels during tumor growth, C57BL/6 and BALB/c were inoculated with Pan02 or CT26 tumor cells, accordingly. The tumors significantly differed in the growth and the mortality of mice. However, the blood chemokine levels did not change in tumor-bearing mice until the very late stages. Taken collectively, blood chemokine level is highly variable and reflects in situ homeostasis. Care should be taken when considering chemokines as prognostic parameters or therapeutic targets in cancer.

Biofabrication of a Tri-layered 3D-Bioprinted CSC-based Malignant Melanoma Model for Personalized Cancer Treatment

Conventional in vitro cancer models do not accurately reproduce the tumor microenvironment, so 3D-bioprinting represents an excellent tool to overcome their limitations. Here, two multicellular tri-layered malignant melanoma (MM) models composed by cancer stem cells isolated from a MM established cell line or a primary-patient derived cell line, fibroblasts, mesenchymal stem cells, and endothelial cells, embedded within an agarose-collagen type I hydrogel were bioprinted. Embedded-cells showed high proliferation and metabolic activity, and actively remodeled their TME. MM hydrogels displayed similar rheological properties that skin and were able to support an early onset of vascularization. Besides, MM hydrogels displayed different response to vemurafenib compared with cell cultures, and supported tumorigenesis in murine xenotransplant achieving more mimetic in vivo models. For the first time a tri-layered 3D-bioprinted CSC-based human MM model is developed recreating TME in vitro and in vivo and response to treatment, being useful for precision treatment regimens against MM.

Fusion between Glioma Stem Cells and Mesenchymal Stem Cells Promotes Malignant Progression in 3D-Bioprinted Models

The interaction between glioma stem cells (GSCs) and mesenchymal stem cells (MSCs) in the glioma microenvironment is considered to be an important factor in promoting tumor progression, but the mechanism is still not fully elucidated. To further elucidate the interaction between GSCs and MSCs, two 3D-bioprinted tumor models (low-temperature molding and coaxial bioprinting) were used to simulate the tumor growth microenvironment. Cell fusion between GSCs and MSCs was found by the method of Cre-LoxP switch gene and RFP/GFP dual-color fluorescence tracing. The fused cells coexpressed biomarkers of GSCs and MSCs, showing stronger proliferation, cloning, and invasion abilities than GSCs and MSCs. In addition, the fused cells have stronger tumorigenic properties in nude mice, showing the pathological features of malignant tumors. In conclusion, GSCs and MSCs undergo cell fusion in 3D-bioprinted models, and the fused cells have a higher degree of malignancy than parental cells, which promotes the progression of glioma.

Lyz2-Cre-Mediated Genetic Deletion of Septin7 Reveals a Role of Septins in Macrophage Cytokinesis and Kras-Driven Tumorigenesis

By crossing septin7-floxed mice with Lyz2-Cre mice carrying the Cre recombinase inserted in the Lysozyme-M (Lyz2) gene locus we aimed the specific deletion of septin7 in myeloid cells, such as monocytes, macrophages and granulocytes. Septin7 ^flox/flox :Lyz2-Cre mice show no alterations in the myeloid compartment. Septin7-deleted macrophages (BMDMs) were isolated and analyzed. The lack of Septin7 expression was confirmed and a constitutive double-nucleation was detected in Septin7-deficient BMDMs indicating a defect in macrophage cytokinesis. However, phagocytic function of macrophages as judged by uptake of labelled E. coli particles and LPS-stimulated macrophage activation as judged by induction of TNF mRNA expression and TNF secretion were not compromised. In addition to myeloid cells, Lyz2-Cre is also active in type II pneumocytes (AT2 cells). We monitored lung adenocarcinoma formation in these mice by crossing them with the conditional knock-in Kras-LSL-G12D allele. Interestingly, we found that control mice without septin7 depletion die after 3-5 weeks, while the Septin7-deficient animals survived 11 weeks or even longer. Control mice sacrificed in the age of 4 weeks display a bronchiolo-alveolar hyperplasia with multiple adenomas, whereas the Septin7-deficient animals of the same age are normal or show only a weak multifocal brochiolo-alveolar hyperplasia. Our findings indicate an essential role of Septin7 in macrophage cytokinesis but not in macrophage function. Furthermore, septin7 seems absolutely essential for oncogenic Kras-driven lung tumorigenesis making it a potential target for anti-tumor interventions.

Development of a Hybrid Nanoink for 3D Bioprinting of Heterogeneous Tumor Models

Despite the rapid progress in applying three-dimensional (3D) printing in the field of tissue engineering, fabrication of heterogeneous and complex 3D tumor models remains a challenge. In this study, we report a hybrid nanoink (AGC) composed of alginate, gelatin methacryloyl (GelMA), and cellulose nanocrystal (CNC), designed for multinozzle microextrusion 3D printing of tumor models. Our results show that the ink consisting of 2 wt % alginate, 4 wt % GelMA, and 6 wt % cellulose nanocrystals (AGC246) possesses a superior shear-thinning property and little hysteresis in viscosity recovery. The fabrication of a colorectal cancer (CRC) model is demonstrated by printing a 3D topological substrate with AGC246 and then seeding/printing endothelial (EA-hy 926) and colorectal carcinoma (HCT 116) cells on top. Direct seeding of cells by dropping a cell suspension onto the 3D substrate with distinctive topological features (villi and trenches) deemed inadequate in either creating a monolayer of endothelial cells or precise positioning of cancer cell clusters, even with surface treatment to promote cell adhesion. In contrast, 3D biopinting of a CRC model using cell-laden AGC153, coupled with dual ultraviolet (UV) and ionic cross-linking, is shown to be successful. Hence, this study brings advancements in 3D bioprinting technology through innovative material and methodology designs, which could enable the fabrication of complex in vitro models for both fundamental studies of disease processes and applications in drug screening.