3D extracellular matrix microenvironment in bioengineered tissue models of primary pediatric and adult brain tumors

Advancing Drug Discovery for Neurological Disorders Using iPSC-Derived Neural Organoids

In the last decade, different research groups in the academic setting have developed induced pluripotent stem cell-based protocols to generate three-dimensional, multicellular, neural organoids. Their use to model brain biology, early neural development, and human diseases has provided new insights into the pathophysiology of neuropsychiatric and neurological disorders, including microcephaly, autism, Parkinson’s disease, and Alzheimer’s disease. However, the adoption of organoid technology for large-scale drug screening in the industry has been hampered by challenges with reproducibility, scalability, and translatability to human disease. Potential technical solutions to expand their use in drug discovery pipelines include Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) to create isogenic models, single-cell RNA sequencing to characterize the model at a cellular level, and machine learning to analyze complex data sets. In addition, high-content imaging, automated liquid handling, and standardized assays represent other valuable tools toward this goal. Though several open issues still hamper the full implementation of the organoid technology outside academia, rapid progress in this field will help to prompt its translation toward large-scale drug screening for neurological disorders.

Therapeutic Efficacy and Biodistribution of Paclitaxel-Bound Amphiphilic Cyclodextrin Nanoparticles: Analyses in 3D Tumor Culture and Tumor-Bearing Animals In Vivo

The uniqueness of paclitaxel’s antimitotic action mechanism has fueled research toward its application in more effective and safer cancer treatments. However, the low water solubility, recrystallization, and side effects hinder the clinical success of classic paclitaxel chemotherapy. The aim of this study was to evaluate the in vivo efficacy and biodistribution of paclitaxel encapsulated in injectable amphiphilic cyclodextrin nanoparticles of different surface charges. It was found that paclitaxel-loaded amphiphilic cyclodextrin nanoparticles showed an antitumoral effect earlier than the drug solution. Moreover, the blank nanoparticles reduced the tumor growth with a similar trend to the paclitaxel solution. At 24 h, the nanoparticles had not accumulated in the heart and lungs according to the biodistribution assessed by in vivo imaging. Therefore, our results indicated that the amphiphilic cyclodextrin nanoparticles are potentially devoid of cardiac toxicity, which limits the clinical use and commercialization of certain polymeric nanoparticles. In conclusion, the amphiphilic cyclodextrin nanoparticles with different surface charge increased the efficiency of paclitaxel in vitro and in vivo. Cyclodextrin nanoparticles could be a good candidate vehicle for intravenous paclitaxel delivery.

Personalizing Oncolytic Virotherapy for Glioblastoma: In Search of Biomarkers for Response

Simple Summary

Glioblastoma (GBM) is the most frequent and aggressive primary brain tumor. Despite multimodal treatment, the prognosis of GBM patients remains very poor. Oncolytic virotherapy is being evaluated as novel treatment for this patient group and clinical trials testing oncolytic viruses have shown impressive responses, albeit in a small subset of GBM patients. Obtaining insight into specific tumor- or patient-related characteristics of the responding patients, may in the future improve response rates. In this review we discuss factors related to oncolytic activity of the most widely applied oncolytic virus strains as well as potential biomarkers and future assays that may allow us to predict response to these agents. Such biomarkers and tools may in the future enable personalizing oncolytic virotherapy for GBM patients.

Abstract

Oncolytic virus (OV) treatment may offer a new treatment option for the aggressive brain tumor glioblastoma. Clinical trials testing oncolytic viruses in this patient group have shown promising results, with patients achieving impressive long-term clinical responses. However, the number of responders to each OV remains low. This is thought to arise from the large heterogeneity of these tumors, both in terms of molecular make-up and their immune-suppressive microenvironment, leading to variability in responses. An approach that may improve response rates is the personalized utilization of oncolytic viruses against Glioblastoma (GBM), based on specific tumor- or patient-related characteristics. In this review, we discuss potential biomarkers for response to different OVs as well as emerging ex vivo assays that in the future may enable selection of optimal OV for a specific patient and design of stratified clinical OV trials for GBM.

Advances in Engineering Human Tissue Models

Research in cell biology greatly relies on cell-based in vitro assays and models that facilitate the investigation and understanding of specific biological events and processes under different conditions. The quality of such experimental models and particularly the level at which they represent cell behavior in the native tissue, is of critical importance for our understanding of cell interactions within tissues and organs. Conventionally, in vitro models are based on experimental manipulation of mammalian cells, grown as monolayers on flat, two-dimensional (2D) substrates. Despite the amazing progress and discoveries achieved with flat biology models, our ability to translate biological insights has been limited, since the 2D environment does not reflect the physiological behavior of cells in real tissues. Advances in 3D cell biology and engineering have led to the development of a new generation of cell culture formats that can better recapitulate the in vivo microenvironment, allowing us to examine cells and their interactions in a more biomimetic context. Modern biomedical research has at its disposal novel technological approaches that promote development of more sophisticated and robust tissue engineering in vitro models, including scaffold- or hydrogel-based formats, organotypic cultures, and organs-on-chips. Even though such systems are necessarily simplified to capture a particular range of physiology, their ability to model specific processes of human biology is greatly valued for their potential to close the gap between conventional animal studies and human (patho-) physiology. Here, we review recent advances in 3D biomimetic cultures, focusing on the technological bricks available to develop more physiologically relevant in vitro models of human tissues. By highlighting applications and examples of several physiological and disease models, we identify the limitations and challenges which the field needs to address in order to more effectively incorporate synthetic biomimetic culture platforms into biomedical research.

Organ-Level Functional 3D Tissue Constructs with Complex Compartments and their Preclinical Applications

There is an increasing interest in organ-level 3D tissue constructs, owing to their mirroring of in vivo-like features. This has resulted in a wide range of preclinical applications to obtain cell- or tissue-specific responses. Additionally, the development and improvement of sophisticated technologies, such as organoid generation, microfluidics, hydrogel engineering, and 3D printing, have enhanced 3D tissue constructs to become more elaborate. In particular, recent studies have focused on including complex compartments, i.e., vascular and innervation structured 3D tissue constructs, which mimic the nature of the human body in that all tissues/organs are interconnected and physiological phenomena are mediated through vascular and neural systems. Here, the strategies are categorized according to the number of dimensions (0D, 1D, 2D, and 3D) of the starting materials for scaling up, and novel approaches to introduce increased complexity in 3D tissue constructs are highlighted. Recent advances in preclinical applications are also investigated to gain insight into the future direction of 3D tissue construct research. Overcoming the challenges in improving organ-level functional 3D tissue constructs both in vitro and in vivo will ultimately become a life-saving tool in the biomedical field.

Organotypic Modeling of the Tumor Landscape

Cancer is a complex disease and it is now clear that not only epithelial tumor cells play a role in carcinogenesis. The tumor microenvironment is composed of non-stromal cells, including endothelial cells, adipocytes, immune and nerve cells, and a stromal compartment composed of extracellular matrix, cancer-associated fibroblasts and mesenchymal cells. Tumorigenesis is a dynamic process with constant interactions occurring between the tumor cells and their surroundings. Even though all connections have not yet been discovered, it is now known that crosstalk between actors of the microenvironment drives cancer progression. Taking into account this complexity, it is important to develop relevant models to study carcinogenesis. Conventional 2D culture models fail to represent the entire tumor microenvironment properly and the use of animal models should be decreased with respect to the 3Rs rule. To this aim, in vitro organotypic models have been significantly developed these past few years. These models have different levels of complexity and allow the study of tumor cells alone or in interaction with the microenvironment actors during the multiple stages of carcinogenesis. This review depicts recent insights into organotypic modeling of the tumor and its microenvironment all throughout cancer progression. It offers an overview of the crosstalk between epithelial cancer cells and their microenvironment during the different phases of carcinogenesis, from the early cell autonomous events to the late metastatic stages. The advantages of 3D over classical 2D or in vivo models are presented as well as the most promising organotypic models. A particular focus is made on organotypic models used for studying cancer progression, from the less complex spheroids to the more sophisticated body-on-a-chip. Last but not least, we address the potential benefits of these models in personalized medicine which is undoubtedly a domain paving the path to new hopes in terms of cancer care and cure.

Upgrading the Physiological Relevance of Human Brain Organoids

The recent advent of human pluripotent stem cell (PSC)-derived 3D brain organoids has opened a window into aspects of human brain development that were not accessible before, allowing tractable monitoring and assessment of early developmental processes. However, their broad and effective use for modeling later stages of human brain development and disease is hampered by the lack of a stereotypic anatomical organization, which limits maturation processes dependent upon formation of unique cellular interactions and short- and long-range network connectivity. Emerging methods and technologies aimed at tighter regulatory control through bioengineering approaches, along with newer unbiased organoid analysis readouts, should resolve several of the current limitations. Here, we review recent advances in brain organoid generation and characterization with a focus on highlighting future directions utilizing interdisciplinary strategies that will be important for improving the physiological relevance of this model system.

Innovations in 3-Dimensional Tissue Models of Human Brain Physiology and Diseases

3-dimensional (3D) laboratory tissue cultures have emerged as an alternative to traditional 2-dimensional (2D) culture systems that do not recapitulate native cell behavior. The discrepancy between in vivo and in vitro tissue-cell-molecular responses impedes understanding of human physiology in general and creates roadblocks for the discovery of therapeutic solutions. Two parallel approaches have emerged for the design of 3D culture systems. The first is biomedical engineering methodology, including bioengineered materials, bioprinting, microfluidics and bioreactors, used alone or in combination, to mimic the microenvironments of native tissues. The second approach is organoid technology, in which stem cells are exposed to chemical and/or biological cues to activate differentiation programs that are reminiscent of human (prenatal) development. This review article describes recent technological advances in engineering 3D cultures that more closely resemble the human brain. The contributions of in vitro 3D tissue culture systems to new insights in neurophysiology, neurological diseases and regenerative medicine are highlighted. Perspectives on designing improved tissue models of the human brain are offered, focusing on an integrative approach merging biomedical engineering tools with organoid biology.

3D Perfusable Hydrogel Recapitulating the Cancer Dynamic Environment to in Vitro Investigate Metastatic Colonization

Metastasis is a dynamic process involving the dissemination of circulating tumor cells (CTCs) through blood flow to distant tissues within the body. Nevertheless, the development of an in vitro platform that dissects the crucial steps of metastatic cascade still remains a challenge. We here developed an in vitro model of extravasation composed of (i) a single channel-based 3D cell laden hydrogel representative of the metastatic site, (ii) a circulation system recapitulating the bloodstream where CTCs can flow. Two polymers (i.e., fibrin and alginate) were tested and compared in terms of mechanical and biochemical proprieties. Computational fluid-dynamic (CFD) simulations were also performed to predict the fluid dynamics within the polymeric matrix and, consequently, the optimal culture conditions. Next, once the platform was validated through perfusion tests by fluidically connecting the hydrogels with the external circuit, highly metastatic breast cancer cells (MDA-MB-231) were injected and exposed to physiological wall shear stress (WSS) conditions (5 Dyn/cm2) to assess their migration toward the hydrogel. Results indicated that CTCs arrested and colonized the polymeric matrix, showing that this platform can be an effective fluidic system to model the first steps occurring during the metastatic cascade as well as a potential tool to in vitro elucidate the contribution of hemodynamics on cancer dissemination to a secondary site.

Three dimensional engineered models to study hypoxia biology in breast cancer

Breast cancer is the second leading cause of mortality among women worldwide. Despite the available therapeutic regimes, variable treatment response is reported among different breast cancer subtypes. Recently, the effects of the tumor microenvironment on tumor progression as well as treatment responses have been widely recognized. Hypoxia and hypoxia inducible factors in the tumor microenvironment have long been known as major players in tumor progression and survival. However, the majority of our understanding of hypoxia biology has been derived from two dimensional (2D) models. Although many hypoxia-targeted therapies have elicited promising results in vitro and in vivo, these results have not been successfully translated into clinical trials. These limitations of 2D models underscore the need to develop and integrate three dimensional (3D) models that recapitulate the complex tumor-stroma interactions in vivo. This review summarizes role of hypoxia in various hallmarks of cancer progression. We then compare traditional 2D experimental systems with novel 3D tissue-engineered models giving accounts of different bioengineering platforms available to develop 3D models and how these 3D models are being exploited to understand the role of hypoxia in breast cancer progression.

Nonlinear Optical Microscopy: From Fundamentals to Applications in Live Bioimaging

A recent challenge in the field of bioimaging is to image vital, thick, and complex tissues in real time and in non-invasive mode. Among the different tools available for diagnostics, nonlinear optical (NLO) multi-photon microscopy allows label-free non-destructive investigation of physio-pathological processes in live samples at sub-cellular spatial resolution, enabling to study the mechanisms underlying several cellular functions. In this review, we discuss the fundamentals of NLO microscopy and the techniques suitable for biological applications, such as two-photon excited fluorescence (TPEF), second and third harmonic generation (SHG-THG), and coherent Raman scattering (CRS). In addition, we present a few of the most recent examples of NLO imaging employed as a label-free diagnostic instrument to functionally monitor in vitro and in vivo vital biological specimens in their unperturbed state, highlighting the technological advantages of multi-modal, multi-photon NLO microscopy and the outstanding challenges in biomedical engineering applications.

3D bioprinted glioma microenvironment for glioma vascularization

Glioblastoma is the most frequently diagnosed primary malignant brain tumor with unfavourable prognosis and high mortality. One of its key features is the extensive abnormal vascular network. Up to now, the mechanism of angiogenesis and the origin of tumor vascularization remain controversial. It is essential to establish an ideal preclinical tumor model to elucidate the mechanism of tumor vascularization, and the role of tumor cells in this process. In this study, both U118 cell and GSC23 cell exhibited good printability and cell proliferation. Compared with 3D-U118, 3D-GSC23 had a greater ability to form cell spheroids, to secrete vascular endothelial growth factor (VEGFA), and to form tubule-like structures in vitro. More importantly, 3D-glioma stem cells (GSC)23 cells had a greater power to transdifferentiate into functional endothelial cells, and blood vessels composed of tumor cells with an abnormal endothelial phenotype was observed in vivo. In summary, 3D bioprinted hydrogel scaffold provided a suitable tumor microenvironment (TME) for glioma cells and GSCs. This bioprinted model supported a novel TME for the research of glioma cells, especially GSCs in glioma vascularization and therapeutic targeting of tumor angiogenesis.

Functional Characterization of Three-Dimensional Cortical Cultures for In Vitro Modeling of Brain Networks

Three-dimensional (3D) in vitro cultures recapitulate key features of the brain including morphology, cell-cell and cell-extracellular matrix interactions, gradients of factors, and mechanical properties. However, there remains a need for experimental and computational tools to investigate network functions in these 3D models. To address this need, we present an experimental system based on 3D scaffold-based cortical neuron cultures in which we expressed the genetically encoded calcium indicator GCaMP6f to record neuronal activity at the millimeter-scale. Functional neural network descriptors were computed with graph-theory-based network analysis methods, showing the formation of functional networks at 3 weeks of culture. Changes to the functional network properties upon perturbations to glutamatergic neurotransmission or GABAergic neurotransmission were quantitatively characterized. The results illustrate the applicability of our 3D experimental system for the study of brain network development, function, and disruption in a biomimetic microenvironment.

Trends in Bone Metastasis Modeling

Bone is one of the most common sites for cancer metastasis. Bone tissue is composed by different kinds of cells that coexist in a coordinated balance. Due to the complexity of bone, it is impossible to capture the intricate interactions between cells under either physiological or pathological conditions. Hence, a variety of in vivo and in vitro approaches have been developed. Various models of tumor-bone diseases are routinely used to provide valuable information on the relationship between metastatic cancer cells and the bone tissue. Ideally, when modeling the metastasis of human cancers to bone, models would replicate the intra-tumor heterogeneity, as well as the genetic and phenotypic changes that occur with human cancers; such models would be scalable and reproducible to allow high-throughput investigation. Despite the continuous progress, there is still a lack of solid, amenable, and affordable models that are able to fully recapitulate the biological processes happening in vivo, permitting a correct interpretation of results. In the last decades, researchers have demonstrated that three-dimensional (3D) methods could be an innovative approach that lies between bi-dimensional (2D) models and animal models. Scientific evidence supports that the tumor microenvironment can be better reproduced in a 3D system than a 2D cell culture, and the 3D systems can be scaled up for drug screening in the same way as the 2D systems thanks to the current technologies developed. However, 3D models cannot completely recapitulate the inter- and intra-tumor heterogeneity found in patients. In contrast, ex vivo cultures of fragments of bone preserve key cell-cell and cell-matrix interactions and allow the study of bone cells in their natural 3D environment. Moreover, ex vivo bone organ cultures could be a better model to resemble the human pathogenic metastasis condition and useful tools to predict in vivo response to therapies. The aim of our review is to provide an overview of the current trends in bone metastasis modeling. By showing the existing in vitro and ex vivo systems, we aspire to contribute to broaden the knowledge on bone metastasis models and make these tools more appealing for further translational studies.

Extracellular Matrix Mimicking Nanofibrous Scaffolds Modified With Mesenchymal Stem Cell-Derived Extracellular Vesicles for Improved Vascularization

The network structure and biological components of natural extracellular matrix (ECM) are indispensable for promoting tissue regeneration. Electrospun nanofibrous scaffolds have been widely used in regenerative medicine to provide structural support for cell growth and tissue regeneration due to their natural ECM mimicking architecture, however, they lack biological functions. Extracellular vesicles (EVs) are potent vehicles of intercellular communication due to their ability to transfer RNAs, proteins, and lipids, thereby mediating significant biological functions in different biological systems. Matrix-bound nanovesicles (MBVs) are identified as an integral and functional component of ECM bioscaffolds mediating significant regenerative functions. Therefore, to engineer EVs modified electrospun scaffolds, mimicking the structure of the natural EV-ECM complex and the physiological interactions between the ECM and EVs, will be attractive and promising in tissue regeneration. Previously, using one-bead one-compound (OBOC) combinatorial technology, we identified LLP2A, an integrin α4β1 ligand, which had a strong binding to human placenta-derived mesenchymal stem cells (PMSCs). In this study, we isolated PMSCs derived EVs (PMSC-EVs) and demonstrated they expressed integrin α4β1 and could improve endothelial cell (EC) migration and vascular sprouting in an ex vivo rat aortic ring assay. LLP2A treated culture surface significantly improved PMSC-EV attachment, and the PMSC-EV treated culture surface significantly enhanced the expression of angiogenic genes and suppressed apoptotic activity. We then developed an approach to enable "Click chemistry" to immobilize LLP2A onto the surface of electrospun scaffolds as a linker to immobilize PMSC-EVs onto the scaffold. The PMSC-EV modified electrospun scaffolds significantly promoted EC survival and angiogenic gene expression, such as KDR and TIE2, and suppressed the expression of apoptotic markers, such as caspase 9 and caspase 3. Thus, PMSC-EVs hold promising potential to functionalize biomaterial constructs and improve the vascularization and regenerative potential. The EVs modified biomaterial scaffolds can be widely used for different tissue engineering applications.

Mimicking tumor hypoxia and tumor-immune interactions employing three-dimensional in vitro models

The heterogeneous tumor microenvironment (TME) is highly complex and not entirely understood. These complex configurations lead to the generation of oxygen-deprived conditions within the tumor niche, which modulate several intrinsic TME elements to promote immunosuppressive outcomes. Decoding these communications is necessary for designing effective therapeutic strategies that can effectively reduce tumor-associated chemotherapy resistance by employing the inherent potential of the immune system.While classic two-dimensional in vitro research models reveal critical hypoxia-driven biochemical cues, three-dimensional (3D) cell culture models more accurately replicate the TME-immune manifestations. In this study, we review various 3D cell culture models currently being utilized to foster an oxygen-deprived TME, those that assess the dynamics associated with TME-immune cell penetrability within the tumor-like spatial structure, and discuss state of the art 3D systems that attempt recreating hypoxia-driven TME-immune outcomes. We also highlight the importance of integrating various hallmarks, which collectively might influence the functionality of these 3D models.This review strives to supplement perspectives to the quickly-evolving discipline that endeavors to mimic tumor hypoxia and tumor-immune interactions using 3D in vitro models.

Decellularized matrices for tumor cell modeling

Collagen is the main component of the extracellular matrix and it plays a key role in tumor progression. Commercial collagen solutions are derived from animals, such as rat-tail and bovine or porcine skin. Their cost is quite high and the product is stable only at low temperature, with the disadvantage of a short expiring date. Most importantly, lot-to-lot variability can occur and the reconstituted collagen gels differ significantly from native tissues in terms of both structure and stiffness. In this chapter, we describe a straightforward method to use native, collagen rich skin samples derived from by-products of the tanning industry. The protocol proposed preserves the microstructure of the ovine skin collagen network, offering structurally competent and more relevant model to investigate cell behavior in vitro. Other advantages of the proposed procedure consist in the cost-effectiveness of the process and an increased level of reproducibility. The decellularized ovine skin samples support the adhesion and growth of different cancer cell lines (pancreatic, breast and melanoma cells). The proposed decellularized skin scaffolds are meant as future low-cost competitors for conventional porous scaffold derived by biomaterials, since they offer a biomimetic environment for the cells.

Hypoxia Inducible Factors' Signaling in Pediatric High-Grade Gliomas: Role, Modelization and Innovative Targeted Approaches

The brain tumor microenvironment has recently become a major challenge in all pediatric cancers, but especially in brain tumors like high-grade gliomas. Hypoxia is one of the extrinsic tumor features that interacts with tumor cells, but also with the blood-brain barrier and all normal brain cells. It is the result of a dramatic proliferation and expansion of tumor cells that deprive the tissues of oxygen inflow. However, cancer cells, especially tumor stem cells, can endure extreme hypoxic conditions by rescheduling various genes' expression involved in cell proliferation, metabolism and angiogenesis and thus, promote tumor expansion, therapeutic resistance and metabolic adaptation. This cellular adaptation implies Hypoxia-Inducible Factors (HIF), namely HIF-1α and HIF-2α. In pediatric high-grade gliomas (pHGGs), several questions remained open on hypoxia-specific role in normal brain during gliomagenesis and pHGG progression, as well how to model it in preclinical studies and how it might be counteracted with targeted therapies. Therefore, this review aims to gather various data about this key extrinsic tumor factor in pHGGs.

Oncofetal Chondroitin Sulfate: A Putative Therapeutic Target in Adult and Pediatric Solid Tumors

Solid tumors remain a major challenge for targeted therapeutic intervention strategies such as antibody-drug conjugates and immunotherapy. At a minimum, clear and actionable solid tumor targets have to comply with the key biological requirement of being differentially over-expressed in solid tumors and metastasis, in contrast to healthy organs. Oncofetal chondroitin sulfate is a cancer-specific secondary glycosaminoglycan modification to proteoglycans expressed in a variety of solid tumors and metastasis. Normally, this modification is found to be exclusively expressed in the placenta, where it is thought to facilitate normal placental implantation during pregnancy. Informed by this biology, oncofetal chondroitin sulfate is currently under investigation as a broad and specific target in solid tumors. Here, we discuss oncofetal chondroitin sulfate as a potential therapeutic target in childhood solid tumors in the context of current knowhow obtained over the past five years in adult cancers.

Lipid droplets: platforms with multiple functions in cancer hallmarks

Lipid droplets (also known as lipid bodies) are lipid-rich, cytoplasmic organelles that play important roles in cell signaling, lipid metabolism, membrane trafficking, and the production of inflammatory mediators. Lipid droplet biogenesis is a regulated process, and accumulation of these organelles within leukocytes, epithelial cells, hepatocytes, and other nonadipocyte cells is a frequently observed phenotype in several physiologic or pathogenic situations and is thoroughly described during inflammatory conditions. Moreover, in recent years, several studies have described an increase in intracellular lipid accumulation in different neoplastic processes, although it is not clear whether lipid droplet accumulation is directly involved in the establishment of these different types of malignancies. This review discusses current evidence related to the biogenesis, composition and functions of lipid droplets related to the hallmarks of cancer: inflammation, cell metabolism, increased proliferation, escape from cell death, and hypoxia. Moreover, the potential of lipid droplets as markers of disease and targets for novel anti-inflammatory and antineoplastic therapies will be discussed.

Could 3D models of cancer enhance drug screening?

Cancer is a multifaceted pathology, where cellular and acellular players interact to drive cancer progression and, in the worst-case, metastasis. The current methods to investigate the heterogeneous nature of cancer are inadequate, since they rely on 2D cell cultures and animal models. The cell line-based drug efficacy and toxicity assays are not able to predict the tumor response to anti-cancer agents and it is already widely discussed how molecular pathway are not recapitulated in vitro so called flat biology. On the other side, animal models often fail to detect the side-effects of drugs, mimic the metastatic progression or the interaction between cancer and immune system, due to biologic difference in human and animals. Moreover, ethical and regulatory issues limit animal experimentation. Every year pharma/biotech companies lose resources in drug discovery and testing processes that are successful only in 5% of the cases. There is an urgent need to validate accurate and predictive platforms in order to enhance drug-testing process taking into account the physiopathology of the tumor microenvironment. Three dimensional in vitro tumor models could enhance drug manufactures in developing effective drugs for cancer diseases. The 3D in vitro cancer models can improve the predictability of toxicity and drug sensitivity in cancer. Despite the demonstrated advantages of 3D in vitro disease systems when compared to 2D culture and animal models, they still do not reach the standardization required for preclinical trials. This review highlights in vitro models that may be used as preclinical models, accelerating the drug development process towards more precise and personalized standard of care for cancer patients. We describe the state-of-the art of 3D in vitro culture systems, with a focus on how these different approaches could be coupled in order to achieve a compromise between standardization and reliability in recapitulating tumor microenvironment and drug response.