Relevance of 3d culture systems to study osteosarcoma environment

Multibarrier-penetrating drug delivery systems for deep tumor therapy based on synergistic penetration strategy

Nanotherapies, valued for their high efficacy and low toxicity, frequently serve as antitumor treatments, but do not readily penetrate deep into tumor tissues and cells. Here we developed an improved tumor-penetrating peptide (TPP)-based drug delivery system. Briefly, the established TPP iNGR was modified to generate a linear NGR peptide capable of transporting nanotherapeutic drugs into tumors through a CendR pathway-dependent, neuropilin-1 receptor-mediated process. Although TPPs have been reported to reach intended tumor targets, they often fail to penetrate cell membranes to deliver tumoricidal drugs to intracellular targets. We addressed this issue by harnessing cell penetrating peptide technology to develop a liposome-based multibarrier-penetrating delivery system (mbPDS) with improved synergistic drug penetration into deep tumor tissues and cells. The system incorporated doxorubicin-loaded liposomes coated with nona-arginine (R9) CPP and cyclic iNGR (CRNGRGPDC) molecules, yielding Lip-mbPDS. Lip-mbPDS tumor-targeting, tumor cell/tissue-penetrating and antitumor capabilities were assessed using CD13-positive human fibrosarcoma-derived cell (HT1080)-based in vitro and in vivo tumor models. Lip-mbPDS evaluation included three-dimensional layer-by-layer confocal laser scanning microscopy, cell internalization/toxicity assays, three-dimensional tumor spheroid-based penetration assays and antitumor efficacy assays conducted in an animal model. Lip-mbPDS provided enhanced synergistic drug penetration of multiple biointerfaces for potentially deep tumor therapeutic outcomes.

Enhanced Biomimetics of Three-Dimensional Osteosarcoma Models: A Scoping Review

This scoping review evaluated 3D osteosarcoma (OS) models' biomimicry, examining their ability to mimic the tumour microenvironment (TME) and their drug sensitivity. Adhering to PRISMA-ScR guidelines, the systematic search revealed 293 studies, with 70 selected for final analysis. Overall, 64% of 3D OS models were scaffold-based, compared to self-generated spheroid models. Scaffolds generated using native matrix were most common (42%) with collagen I/hydroxyapatite predominating. Both scaffold-based and scaffold-free models were used equally for drug screening. The sensitivity of cancer cells in 3D was reported to be lower than that of cells in 2D in ~90% of the drug screening studies. This correlates with the observed upregulation of drug resistance. OS cells cultured in extracellular matrix (ECM)-mimetic scaffolds and native biomaterials were more resistant than cells in 2D. Co-cultures of OS and stromal cells in 3D models enhanced osteogenic differentiation, ECM remodelling, mineralisation, and angiogenesis, suggesting that tumour-stroma crosstalk promotes disease progression. Seven studies demonstrated selective toxicity of chemotherapeutics towards OS cells while sparing stromal cells, providing useful evidence for developing biomimetic tumour-stroma models to test selective drug toxicity. In conclusion, this review highlights the need to enhance biomimicry in 3D OS models for TME recapitulation, especially in testing novel therapeutics. Future research should explore innovative 3D biomimetic models, biomaterials, and advancements in personalised medicine.

The role of hypoxia and radiation in developing a CTCs-like phenotype in murine osteosarcoma cells

Introduction: Cancer treatment has evolved significantly, yet concerns about tumor recurrence and metastasis persist. Within the dynamic tumor microenvironment, a subpopulation of mesenchymal tumor cells, known as Circulating Cancer Stem Cells (CCSCs), express markers like CD133, TrkB, and CD47, making them radioresistant and pivotal to metastasis. Hypoxia intensifies their stemness, complicating their identification in the bloodstream. This study investigates the interplay of acute and chronic hypoxia and radiation exposure in selecting and characterizing cells with a CCSC-like phenotype. Methods: LM8 murine osteosarcoma cells were cultured and subjected to normoxic (21% O2) and hypoxic (1% O2) conditions. We employed Sphere Formation and Migration Assays, Western Blot analysis, CD133 Cell Sorting, and CD133+ Fluorescent Activated Cell Sorting (FACS) analysis with a focus on TrkB antibody to assess the effects of acute and chronic hypoxia, along with radiation exposure. Results: Our findings demonstrate that the combination of radiation and acute hypoxia enhances stemness, while chronic hypoxia imparts a cancer stem-like phenotype in murine osteosarcoma cells, marked by increased migration and upregulation of CCSC markers, particularly TrkB and CD47. These insights offer a comprehensive understanding of the interactions between radiation, hypoxia, and cellular responses in the context of cancer treatment. Discussion: This study elucidates the complex interplay among radiation, hypoxia, and cellular responses, offering valuable insights into the intricacies and potential advancements in cancer treatment.

Engineered bone marrow as a clinically relevant ex vivo model for primary bone cancer research and drug screening

Osteosarcoma (OS) is the most common primary malignant bone cancer in children and adolescents. While numerous other cancers now have promising therapeutic advances, treatment options for OS have remained unchanged since the advent of standard chemotherapeutics and offer less than a 25% 5-y survival rate for those with metastatic disease. This dearth of clinical progress underscores a lack of understanding of OS progression and necessitates the study of this disease in an innovative system. Here, we adapt a previously described engineered bone marrow (eBM) construct for use as a three-dimensional platform to study how microenvironmental and immune factors affect OS tumor progression. We form eBM by implanting acellular bone-forming materials in mice and explanting the cellularized constructs after 8 wk for study. We interrogate the influence of the anatomical implantation site on eBM tissue quality, test ex vivo stability under normoxic (5% O2) and standard (21% O2) culture conditions, culture OS cells within these constructs, and compare them to human OS samples. We show that eBM stably recapitulates the composition of native bone marrow. OS cells exhibit differential behavior dependent on metastatic potential when cultured in eBM, thus mimicking in vivo conditions. Furthermore, we highlight the clinical applicability of eBM as a drug-screening platform through doxorubicin treatment and show that eBM confers a protective effect on OS cells that parallel clinical responses. Combined, this work presents eBM as a cellular construct that mimics the complex bone marrow environment that is useful for mechanistic bone cancer research and drug screening.

Advances of Osteosarcoma Models for Drug Discovery and Precision Medicine

The management of osteosarcoma (OS) patients presents a significant clinical challenge. Despite progress in conventional and targeted therapies, the survival rate of OS patients remains limited largely due to therapy resistance and the high metastatic potential of the disease. OS models that accurately reflect the fundamental characteristics are vital to the innovation and validation of effective therapies. This review provides an insight into the advances and challenges in OS drug development, focusing on various preclinical models, including cell lines, 3D culture models, murine models, and canine models. The relevance, strengths, and limitations of each model in OS research are explored. In particular, we highlight a range of potential therapeutics identified through these models. These instances of successful drug development represent promising pathways for personalized OS treatment.

Three-Dimensional Cell Cultures: The Bridge between In Vitro and In Vivo Models

Although historically, the traditional bidimensional in vitro cell system has been widely used in research, providing much fundamental information regarding cellular functions and signaling pathways as well as nuclear activities, the simplicity of this system does not fully reflect the heterogeneity and complexity of the in vivo systems. From this arises the need to use animals for experimental research and in vivo testing. Nevertheless, animal use in experimentation presents various aspects of complexity, such as ethical issues, which led Russell and Burch in 1959 to formulate the 3R (Replacement, Reduction, and Refinement) principle, underlying the urgent need to introduce non-animal-based methods in research. Considering this, three-dimensional (3D) models emerged in the scientific community as a bridge between in vitro and in vivo models, allowing for the achievement of cell differentiation and complexity while avoiding the use of animals in experimental research. The purpose of this review is to provide a general overview of the most common methods to establish 3D cell culture and to discuss their promising applications. Three-dimensional cell cultures have been employed as models to study both organ physiology and diseases; moreover, they represent a valuable tool for studying many aspects of cancer. Finally, the possibility of using 3D models for drug screening and regenerative medicine paves the way for the development of new therapeutic opportunities for many diseases.

Cold plasma and inhibition of STAT3 selectively target tumorigenicity in osteosarcoma

Osteosarcoma (OS) is a malignant type of bone cancer that arises in periods of increased bone formation. Curative strategies for these types of tumors have remained essentially unchanged for decades and the overall survival for most advanced cases is still dismally low. This is in part due to the existence of drug resistant Cancer Stem Cells (CSC) with progenitor properties that are responsible for tumor relapse and metastasis. In the quest for therapeutic alternatives for OS, Cold Atmospheric Plasmas and Plasma-Treated Liquids (PTL) have come to the limelight as a source of Reactive Oxygen and Nitrogen Species displaying selectivity towards a variety of cancer cell lines. However, their effects on CSC subpopulations and in vivo tumor growth have been barely studied to date. By employing bioengineered 3D tumor models and in vivo assays, here we show that low doses of PTL increase the levels of pro-stemness factors and the self-renewal ability of OS cells, coupled to an enhanced in vivo tumor growth potential. This could have critical implications to the field. By proposing a combined treatment, our results demonstrate that the deleterious pro-stemness signals mediated by PTL can be abrogated when this is combined with the STAT3 inhibitor S3I-201, resulting in a strong suppression of in vivo tumor growth. Overall, our study unveils an undesirable stem cell-promoting function of PTL in cancer and supports the use of combinatorial strategies with STAT3 inhibitors as an efficient treatment for OS avoiding critical side effects. We anticipate our work to be a starting point for wider studies using relevant 3D tumor models to evaluate the effects of plasma-based therapies on tumor subpopulations of different cancer types. Furthermore, combination with STAT3 inhibition or other suitable cancer type-specific targets can be relevant to consolidate the development of the field.

Exploring the Use of Cold Atmospheric Plasma to Overcome Drug Resistance in Cancer

Drug resistance is a major problem in cancer treatment, as it limits the effectiveness of pharmacological agents and can lead to disease progression. Cold atmospheric plasma (CAP) is a technology that uses ionized gas (plasma) to generate reactive oxygen and nitrogen species (RONS) that can kill cancer cells. CAP is a novel approach for overcoming drug resistance in cancer. In recent years, there has been a growing interest in using CAP to enhance the effectiveness of chemotherapy drugs. In this review, we discuss the mechanisms behind this phenomenon and explore its potential applications in cancer treatment. Going through the existing literature on CAP and drug resistance in cancer, we highlight the challenges and opportunities for further research in this field. Our review suggests that CAP could be a promising option for overcoming drug resistance in cancer and warrants further investigation.

Gallic acid mediates tumor-suppressive effects on osteosarcoma through the H19-Wnt/β-catenin regulatory axis

Background

Osteosarcoma (OS) is the most common primary malignancy in bone tissues, and effective therapeutics remain absent in clinical practice. Traditional Chinese medicines (TCM) have been used for thousands of years, which provide great insights into OS management. Gallic acid (GA) is a natural phenolic acid enriched in various foods and herbs. Several pharmacological activities of GA such as anti-oxidation and anti-inflammation have been well-established. However, its biological function in OS remains not fully understood.

Methods

The potential anti-cancer properties of GA were evaluated in 143 ​B, U2OS and MG63 ​cells. Its effects on cell growth, cell cycle, apoptosis and migration were examined in these OS cells. The lncRNA H19 and Wnt/β-catenin signaling were detected by qPCR, luciferase activity and Western blotting assays. The in vivo effect of GA on tumor growth was investigated using an orthotopic mouse model.

Results

In the present study, GA was found to suppress the tumor growth in vitro via inducing cell cycle arrest and apoptosis in OS cells, and inhibit the invasion and metastasis as well. Using the orthotopic animal model, GA was also found to suppress tumorigenesis in vivo. Long noncoding RNA (lncRNA) H19 was demonstrated to be down-regulated by GA, and thus disrupted the canonical Wnt/β-catenin signaling in OS cells. Furthermore, the ectopic expression of H19 rescued the GA-induced suppressive effects on tumor growth and metastasis, and partially reversed the inactivation of Wnt/β-catenin signaling.

Conclusions

Taken together, our results indicated that GA inhibited tumor growth through an H19-mediated Wnt/β-catenin signaling regulatory axis in OS cells.

The translational potential of this article

The information gained from this study provides a novel underlying mechanism of GA mediated anti-OS activity, suggesting that GA may be a promising drug candidate for OS patients.

Ageing and Osteoarthritis Synergically Affect Human Synoviocyte Cells: An In Vitro Study on Sex Differences

Osteoarthritis is a chronic inflammatory disease that affects all of the joints, especially those of the elderly. Aging is a natural and irreversible biological process implicated in the pathophysiology of many chronic diseases, such as osteoarthritis. Inflammation and oxidative stress are the main factors involved in osteoarthritis and aging, respectively, with the production of several pro-inflammatory cytokines such as Interleukin 1β (IL1β) and reactive oxygen species. The aim of the study was to set-up an in vitro model of osteoarthritis and aging, focusing on the sex differences by culturing male and female fibroblast-like synoviocytes (FLSs) with IL1β, hydrogen peroxide (H₂O₂), IL1β+H₂O₂ or a growth medium (control). IL1β+H₂O₂ reduced the cell viability and microwound healing potential, increased Caspase-3 expression and reactive oxygen species and IL6 production; IL1β increased IL6 production more than the other conditions did; H₂O₂ increased Caspase-3 expression and reactive oxygen species production; Klotho expression showed no differences among the treatments. The FLSs from female donors demonstrated a better response capacity in unfavorable conditions of inflammation and oxidative stress than those from the male donors did. This study developed culture conditions to mimic the aging and osteoarthritis microenvironment to evaluate the behavior of the FLSs which play a fundamental role in joint homeostasis, focusing on the sex-related aspects that are relevant in the osteoarthritis pathophysiology.

Cold atmospheric plasma enhances doxorubicin selectivity in metastasic bone cancer

High-dose systemic chemotherapy constitutes a main strategy in the management of bone metastases, employing drugs like doxorubicin (DOX), related with severe side effects. To solve this issue, Cold Atmospheric Plasmas (CAP) have been proposed as potential non-invasive anti-cancer agents capable of improving the efficacy of traditional drugs. Here, we investigate the cytotoxic effects of Plasma Conditioned Medium (PCM) in combination with DOX in prostate cancer cells from bone metastases (PC-3) as well as in non-malignant bone-cells. PCM was able to enhance the cytotoxic potential of DOX both in monolayer and in a 3D bioengineered model mimicking the bone matrix. The combined treatment of PCM + DOX resulted in a profound downregulation of the redox defenses (CAT1, SOD2, GPX1) and drug resistance genes (MRP1, MDR1, BCRP1), resulting in an enhanced uptake of DOX coupled to an overload of intracellular ROS. Besides, PCM improved the cytotoxic potential of DOX interfering on the migratory and clonogenic potential of PC-3 cells. Importantly, non-malignant bone cells were unaffected by the combination of PCM + DOX. Overall, these new findings may represent a new therapeutic approach for the management of bone metastatic prostate cancer in the future.

Traditional Medicinal Plants as a Source of Inspiration for Osteosarcoma Therapy

Osteosarcoma is one of the most common types of bone cancers among paediatric patients. Despite the advances made in surgery, chemo-, and radiotherapy, the mortality rate of metastatic osteosarcoma remains unchangeably high. The standard drug combination used to treat this bone cancer has remained the same for the last 20 years, and it produces many dangerous side effects. Through history, from ancient to modern times, nature has been a remarkable source of chemical diversity, used to alleviate human disease. The application of modern scientific technology to the study of natural products has identified many specific molecules with anti-cancer properties. This review describes the latest discovered anti-cancer compounds extracted from traditional medicinal plants, with a focus on osteosarcoma research, and on their cellular and molecular mechanisms of action. The presented compounds have proven to kill osteosarcoma cells by interfering with different pathways: apoptosis induction, stimulation of autophagy, generation of reactive oxygen species, etc. This wide variety of cellular targets confer natural products the potential to be used as chemotherapeutic drugs, and also the ability to act as sensitizers in drug combination treatments. The major hindrance for these molecules is low bioavailability. A problem that may be solved by chemical modification or nano-encapsulation.

Placental model as an important tool to study maternal-fetal interface

The placenta is a temporary organ that plays critical roles at the maternal-fetal interface. Normal development and function of the placenta is dependent on hormonal signaling pathways that make the placenta a target of endocrine disrupting chemical (EDC) action. Studies showing association between prenatal exposure, hormone disruption, and reproductive damage indicate that EDCs are developmentally toxic and can impact future generations. In this context, new placental models (trophoblast-derived cell lines, organotypic or 3D cell models, and physiologically based kinetic models) have been developed in order to create new approach methodology (NAM) to assess and even prevent such disastrous toxic harm in future generations. With the widespread discouragement of conducting animal studies, it has become irrefutable to develop in vitro models that can serve as a substitute for in vivo models. The goal of this review is to discuss the newest in vitro models to understand the maternal-fetal interface and predict placental development, physiology, and dysfunction generated by failures in molecular hormone control mechanisms, which, consequently, may change epigenetic programming to increase susceptibility to metabolic and other disorders in the offspring. We summarize the latest placental models for developmental toxicology studies, focusing mainly on three-dimensional (3D) culture models.

Multiple Effects of Resveratrol on Osteosarcoma Cell Lines

Osteosarcoma (OS) is the most common primary bone sarcoma affecting the life of pediatric patients. The clinical treatment faces numerous difficulties, including the adverse effects of chemotherapies, chemoresistance, and recurrences. In this study, the effects of resveratrol (RSV), a natural polyphenol, on OS cell lines were investigated to evaluate its action as an adjuvant therapy to the current chemotherapy regimens. RSV exhibited multiple tumor-suppressing activities on OS cell lines, inducing a series of critical events. We found (1) a cell growth inhibition due to an increase in cell distress, which was, in part, due to the involvement of the AKT and caspase-3 pathways, (2) an increase in cellular differentiation due to major gene expression levels of the osteoblastic differentiation genes, (3) an inhibition of IL-6 secretion due to an epigenetic effect on the IL-6 promoter, and (4) an inhibition of OS cells migration related to the decrease in IL-8 secretion levels due to an epigenetic effect on its promoter. Finally, the cotreatment of RSV with doxorubicin and cisplatin increased their cytotoxic effect on OS cells. Although further investigations are mandatory, it seems RSV might be a promising therapeutic adjuvant agent for OS cell treatment, exerting an antitumor effect when combined with chemotherapy.

A murine mesenchymal stem cell model for initiating events in osteosarcomagenesis points to CDK4/CDK6 inhibition as a therapeutic target

Osteosarcoma is a high-grade bone-forming neoplasm, with a complex genome. Tumours frequently show chromothripsis, many deletions, translocations and copy number alterations. Alterations in the p53 or Rb pathway are the most common genetic alterations identified in osteosarcoma. Using spontaneously transformed murine mesenchymal stem cells (MSCs) which formed sarcoma after subcutaneous injection into mice, it was previously demonstrated that p53 is most often involved in the transformation towards sarcomas with complex genomics, including osteosarcoma. In the current study, not only loss of p53 but also loss of p16^Ink4a is shown to be a driver of osteosarcomagenesis: murine MSCs with deficient p15^Ink4b, p16^Ink4a, or p19^Arf transform earlier compared to wild-type murine MSCs. Furthermore, in a panel of nine spontaneously transformed murine MSCs, alterations in p15^Ink4b, p16^Ink4a, or p19^Arf were observed in eight out of nine cases. Alterations in the Rb/p16 pathway could indicate that osteosarcoma cells are vulnerable to CDK4/CDK6 inhibitor treatment. Indeed, using two-dimensional (n = 7) and three-dimensional (n = 3) cultures of human osteosarcoma cell lines, it was shown that osteosarcoma cells with defective p16^INK4A are sensitive to the CDK4/CDK6 inhibitor palbociclib after 72-hour treatment. A tissue microarray analysis of 109 primary tumour biopsies revealed a subset of patients (20-23%) with intact Rb, but defective p16 or overexpression of CDK4 and/or CDK6. These patients might benefit from CDK4/CDK6 inhibition, therefore our results are promising and might be translated to the clinic.

3D Printed Multifunctional Ti6Al4V-Based Hybrid Scaffold for the Management of Osteosarcoma

Osteosarcoma is a challenging bone disease which is commonly associated with critically sized bone defects and cancer recurrence. Here, we designed and developed a multifunctional, hierarchical structured bone scaffold which can meet the demanding requirements for osteosarcoma management. The 3D printed Ti₆Al₄V scaffold with hydrothermally induced TiO₂/TiP coating can offer a unique photothermal conversion property for in vitro bone cancer ablation. The scaffold is also infused with drug-laden gelatin/hydroxyapatite nanocomposite, which provides the ideal porous structure for cell adhesion/bone ingrowth and promotes bone regeneration. The scaffold has been thoroughly characterized by SEM/EDX, TEM, XPS, XRD, TGA, and UV-vis, and its in vitro bone cancer ablation efficiency has been validated using MG-63 cells. The hybrid scaffold showed excellent biocompatibility, and its osteointegration function has been demonstrated using an animal model.

Three dimensional in vitro culture systems in anticancer drug discovery targeted on cancer stem cells

Worldwide, tumors are one of the most common causes of death. Every year 3.7 million new cases occur in Europe and more than 1.9 million patients die (WHO data). Most of the fields of research are focused on developing new therapeutic strategies that will be effective in eliminating the tumor, preventing its remission, and avoiding or reducing the side effects of therapy. In the past, generally classical 2D cell cultures or immunodeficient animal models had been used to cultivate and test drugs on human cancer cell lines. Nowadays, there are increasing interests in three-dimensional (3D) cell cultures, a method with significant differences from flat cultured cells, both considering gene expressions and cell-cell interactions. Various evidence suggests that high tumorigenic properties might be dependent on the occurrence of a small cell population, pointed out to be responsible for metastasis and recurrence. This population is called cancer stem cells (CSCs), hinted to have a lot of similarities with normal stem cells. CSCs are the main reason for chemotherapy failure as well as multi-drug resistance (MDR). CSCs can also interact through the cytokine network, with other cells like the macrophages of the inflammatory system. The big advantage of a 3D culture is the possibility to isolate and investigate the CSCs population surrounded by its environment. This article aims to sum up known 3D cell cultures, especially in the field of CSCs research due to the importance of the tumor's environment on stem cell's markers expression and their development.

In vitro three-dimensional cell cultures for bone sarcomas

Bone sarcomas are rare tumour entities that arise from the mesenchyme most of which are highly heterogeneous at the cellular, genetic and epigenetic levels. The three main types are osteosarcoma, Ewing sarcoma, and chondrosarcoma. These oncological entities are characterised by high morbidity and mortality and an absence of significant therapeutic improvement in the last four decades. In the field of oncology, in vitro cultures of cancer cells have been extensively used for drug screening unfortunately with limited success. Indeed, despite the massive knowledge acquired from conventional 2D culture methods, scientific community has been challenged by the loss of efficacy of drugs when moved to clinical trials. The recent explosion of new 3D culture methods is paving the way to more relevant in vitro models mimicking the in vivo tumour environment (e.g. bone structure) with biological responses close to the in vivo context. The present review gives a brief overview of the latest advances of the 3D culture methods used for studying primary bone sarcomas.

Integrated multi-omics analyses on patient-derived CRC organoids highlight altered molecular pathways in colorectal cancer progression involving PTEN

Background

Colorectal cancer (CRC) represents the fourth leading cause of cancer-related deaths. The heterogeneity of CRC identity limits the usage of cell lines to study this type of tumor because of the limited representation of multiple features of the original malignancy. Patient-derived colon organoids (PDCOs) are a promising 3D-cell model to study tumor identity for personalized medicine, although this approach still lacks detailed characterization regarding molecular stability during culturing conditions. Correlation analysis that considers genomic, transcriptomic, and proteomic data, as well as thawing, timing, and culturing conditions, is missing.

Methods

Through integrated multi–omics strategies, we characterized PDCOs under different growing and timing conditions, to define their ability to recapitulate the original tumor.

Results

Whole Exome Sequencing allowed detecting temporal acquisition of somatic variants, in a patient-specific manner, having deleterious effects on driver genes CRC-associated. Moreover, the targeted NGS approach confirmed that organoids faithfully recapitulated patients’ tumor tissue. Using RNA-seq experiments, we identified 5125 differentially expressed transcripts in tumor versus normal organoids at different time points, in which the PTEN pathway resulted of particular interest, as also confirmed by further phospho-proteomics analysis. Interestingly, we identified the PTEN c.806_817dup (NM_000314) mutation, which has never been reported previously and is predicted to be deleterious according to the American College of Medical Genetics and Genomics (ACMG) classification.

Conclusion

The crosstalk of genomic, transcriptomic and phosphoproteomic data allowed to observe that PDCOs recapitulate, at the molecular level, the tumor of origin, accumulating mutations over time that potentially mimic the evolution of the patient’s tumor, underlining relevant potentialities of this 3D model.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01986-8.

Employing hydrogels in tissue engineering approaches to boost conventional cancer-based research and therapies

Cancer is a complicated disease that involves the efforts of researchers to introduce and investigate novel successful treatments. Traditional cancer therapy approaches, especially chemotherapy, are prone to possible systemic side effects, such as the dysfunction of liver or kidney, neurological side effects and a decrease of bone marrow activity. Hydrogels, along with tissue engineering techniques, provide tremendous potential for scientists to overcome these issues through the release of drugs at the site of tumor. Hydrogels demonstrated competency as potent and stimulus-sensitive drug delivery systems for tumor removal, which is attributed to their unique features, including high water content, biocompatibility, and biodegradability. In addition, hydrogels have gained more attention as 3D models for easier and faster screening of cancer and tumors due to their potential in mimicking the extracellular matrix. Hydrogels as a reservoir can be loaded by an effective dosage of chemotherapeutic agents, and then deliver them to targets. In comparison to conventional procedures, hydrogels considerably decreased the total cost, duration of research, and treatment time. This study provides a general look into the potential role of hydrogels as a powerful tool to augment cancer studies for better analysis of cancerous cell functions, cell survival, angiogenesis, metastasis, and drug screening. Moreover, the upstanding application of drug delivery systems related to the hydrogel in order to sustain the release of desired drugs in the tumor cell-site were explored.

Cold Atmospheric Plasma: A New Strategy Based Primarily on Oxidative Stress for Osteosarcoma Therapy

Osteosarcoma is the most common primary bone tumor, and its first line of treatment presents a high failure rate. The 5-year survival for children and teenagers with osteosarcoma is 70% (if diagnosed before it has metastasized) or 20% (if spread at the time of diagnosis), stressing the need for novel therapies. Recently, cold atmospheric plasmas (ionized gases consisting of UV-Vis radiation, electromagnetic fields and a great variety of reactive species) and plasma-treated liquids have been shown to have the potential to selectively eliminate cancer cells in different tumors through an oxidative stress-dependent mechanism. In this work, we review the current state of the art in cold plasma therapy for osteosarcoma. Specifically, we emphasize the mechanisms unveiled thus far regarding the action of plasmas on osteosarcoma. Finally, we review current and potential future approaches, emphasizing the most critical challenges for the development of osteosarcoma therapies based on this emerging technique.

Osteosarcoma tissue-engineered model challenges oxidative stress therapy revealing promoted cancer stem cell properties

The use of oxidative stress generated by Cold Atmospheric Plasma (CAP) in oncology is being recently studied as a novel potential anti-cancer therapy. However, the beneficial effects of CAP for treating osteosarcoma have mostly been demonstrated in 2-dimensional cultures of cells, which do not mimic the complexity of the 3-dimensional (3D) bone microenvironment. In order to evaluate the effects of CAP in a relevant context of the human disease, we developed a 3D tissue-engineered model of osteosarcoma using a bone-like scaffold made of collagen type I and hydroxyapatite nanoparticles. Human osteosarcoma cells cultured within the scaffold showed a high capacity to infiltrate and proliferate and to exhibit osteomimicry in vitro. As expected, we observed significantly different functional behaviors between monolayer and 3D cultures when treated with Cold Plasma-Activated Ringer's Solution (PAR). Our data reveal that the 3D environment not only protects cells from PAR-induced lethality by scavenging and diminishing the amount of reactive oxygen and nitrogen species generated by CAP, but also favours the stemness phenotype of osteosarcoma cells. This is the first study that demonstrates the negative effect of PAR on cancer stem-like cell subpopulations in a 3D biomimetic model of cancer. These findings will allow to suitably re-focus research on plasma-based therapies in future.

Benznidazole modulates release of inflammatory mediators by cardiac spheroids infected with Trypanosoma cruzi

Chagas disease (CD) caused by Trypanosoma cruzi remains a serious public health problem in Latin America. The available treatment is limited to two old drugs, benznidazole (Bz) and nifurtimox, which exhibit limited efficacy and trigger side effects, justifying the search for new therapies. Also, more accurate and sensitive experimental protocols for drug discovery programs are necessary to shrink the translational gaps found among pre-clinical and clinical trials. Presently, cardiac spheroids were used to evaluate host cell cytotoxicity and anti-T.cruzi activity of benznidazole, exploring its effect on the release of inflammatory mediators. Bz presented low toxic profile on 3D matrices (LC₅₀ > 200 μM) and high potency in vitro (EC₅₀ = 0.99 μM) evidenced by qPCR analysis of T.cruzi-infected cardiac spheroids. Flow cytometry appraisal of inflammatory mediators released at the cellular supernatant showed increases in IL - 6 and TNF contents (≈190 and ≈ 25-fold) in parasitized spheroids as compared to uninfected cultures. Bz at 10 μM suppressed parasite load (92%) concomitantly decreasing in IL-6 (36%) and TNF (68%). Our findings corroborate the successful use of 3D cardiac matrices for in vitro identification of novel anti-parasitic agents and potential impact in host cell physiology.

Scaffold-based 3D cellular models mimicking the heterogeneity of osteosarcoma stem cell niche

The failure of the osteosarcoma conventional therapies leads to the growing need for novel therapeutic strategies. The lack of specificity for the Cancer Stem Cells (CSCs) population has been recently identified as the main limitation in the current therapies. Moreover, the traditional two-dimensional (2D) in vitro models, employed in the drug testing and screening as well as in the study of cell and molecular biology, are affected by a poor in vitro-in vivo translation ability. To overcome these limitations, this work provides two tumour engineering approaches as new tools to address osteosarcoma and improve therapy outcomes. In detail, two different hydroxyapatite-based bone-mimicking scaffolds were used to recapitulate aspects of the in vivo tumour microenvironment, focusing on CSCs niche. The biological performance of human osteosarcoma cell lines (MG63 and SAOS-2) and enriched-CSCs were deeply analysed in these complex cell culture models. The results highlight the fundamental role of the tumour microenvironment proving the mimicry of osteosarcoma stem cell niche by the use of CSCs together with the biomimetic scaffolds, compared to conventional 2D culture systems. These advanced 3D cell culture in vitro tumour models could improve the predictivity of preclinical studies and strongly enhance the clinical translation.

Creating In Vitro Three-Dimensional Tumor Models: A Guide for the Biofabrication of a Primary Osteosarcoma Model

Osteosarcoma (OS) is a highly aggressive primary bone tumor. The mainstay for its treatment is multiagent chemotherapy and surgical resection, with a 50-70% 5-year survival rate. Despite the huge effort made by clinicians and researchers in the past 30 years, limited progress has been made to improve patient outcomes. As novel therapeutic approaches for OS become available, such as monoclonal antibodies, small molecules, and immunotherapies, the need for OS preclinical model development becomes equally pressing. Three-dimensional (3D) OS models represent an alternative system to study this tumor: In contrast to two-dimensional monolayers, 3D matrices can recapitulate key elements of the tumor microenvironment (TME), such as the cellular interaction with the bone mineralized matrix. The advancement of tissue engineering and biofabrication techniques enables the incorporation of specific TME aspects into 3D models, to investigate the contribution of individual components to tumor progression and enhance understanding of basic OS biology. The use of biomaterials that mimic the extracellular matrix could also facilitate the testing of drugs targeting the TME itself, allowing a larger range of therapeutics to be tested, while averting the ethical implications and high cost associated with in vivo preclinical models. This review aims at serving as a practical guide by delineating the OS TME ("what it is like") and, in turn, propose various biofabrication strategies to create a 3D model ("how to recreate it"), to improve the in vitro representation of the OS tumor and ultimately generate more accurate drug response profiles.

Comparison of VEGF-A secretion from tumor cells under cellular stresses in conventional monolayer culture and microfluidic three-dimensional spheroid models

Vascular endothelial growth factor (VEGF) is a major cytokine in tumor biology affecting tumor survival, aggressiveness and pro-angiogenetic activities. In addition, cellular stresses often result in aggressive pro-angiogenetic behavior in tumors. For in vitro study, conventional monolayer cell culture has been broadly exploited; however, it often provides limited information due to its different microenvironment from that in vivo. Recently, three-dimensional (3D) cell spheroid culture provides in vivo-like microenvironments to study tumor biology and their survival mechanisms with better predictive power. In this work, vascular endothelial growth factor of type A (VEGF-A) secretion from osteosarcoma (MG-63) cells cultured using monolayer and 3D spheroid models under two stress conditions: nutrient deficiency (reduced serum culture) and hypoxia-inducible factor (HIF) inhibition (HIF inhibitor, YC-1) are characterized and systematically compared. In order to obtain ample sample size for consistent characterization of cellular responses from cancer spheroids under the stresses and compare the responses to those from the conventional monolayer model, a microfluidic spheroid formation and culture device is utilized in the experiments. In the analysis, cell viability is estimated from captured images, and quantification of VEGF-A secreted from the cells is achieved using enzyme-linked immunosorbent assay (ELISA). The experimental results show that the viabilities decrease when the cells face higher stress levels in both monolayer and 3D spheroid culture models; however, the VEGF-A secretion profiles between the cell culture models are different. The VEGF-A secretion decreases when the cells face higher stress conditions in the monolayer cell culture. In contrast, for the 3D spheroid culture, the VEGF-A concentration decreases for low stress levels but increases while the stress level is high. The VEGF-A regulation in the 3D models mimics in vivo cases of tumor survival and can provide insightful information to investigate tumor angiogenesis in vitro. The approach developed in this paper provides an efficient method to quantitatively and statistically study tumor growth kinetics and stress responses from highly uniform samples and it can also be applied to compare the underlying biomolecular mechanisms in monolayer and 3D spheroid culture models to elucidate the effects of microenvironments on cellular response in cancer research.

The Role of Pre-Clinical 3-Dimensional Models of Osteosarcoma

Treatment for osteosarcoma (OS) has been largely unchanged for several decades, with typical therapies being a mixture of chemotherapy and surgery. Although therapeutic targets and products against cancer are being continually developed, only a limited number have proved therapeutically active in OS. Thus, the understanding of the OS microenvironment and its interactions are becoming more important in developing new therapies. Three-dimensional (3D) models are important tools in increasing our understanding of complex mechanisms and interactions, such as in OS. In this review, in vivo animal models, in vitro 3D models and in ovo chorioallantoic membrane (CAM) models, are evaluated and discussed as to their contribution in understanding the progressive nature of OS, and cancer research. We aim to provide insight and prospective future directions into the potential translation of 3D models in OS.

Pharmacogenomics and Pharmacogenetics in Osteosarcoma: Translational Studies and Clinical Impact

High-grade osteosarcoma (HGOS) is a very aggressive bone tumor which primarily affects adolescents and young adults. Although not advanced as is the case for other cancers, pharmacogenetic and pharmacogenomic studies applied to HGOS have been providing hope for an improved understanding of the biology and the identification of genetic biomarkers, which may impact on clinical care management. Recent developments of pharmacogenetics and pharmacogenomics in HGOS are expected to: i) highlight genetic events that trigger oncogenesis or which may act as drivers of disease; ii) validate research models that best predict clinical behavior; and iii) indicate genetic biomarkers associated with clinical outcome (in terms of treatment response, survival probability and susceptibility to chemotherapy-related toxicities). The generated body of information may be translated to clinical settings, in order to improve both effectiveness and safety of conventional chemotherapy trials as well as to indicate new tailored treatment strategies. Here, we review and summarize the current scientific evidence for each of the aforementioned issues in view of possible clinical applications.

Modeling the Tumor Microenvironment and Pathogenic Signaling in Bone Sarcoma

Investigations of cancer biology and screening of potential therapeutics for efficacy and safety begin in the preclinical laboratory setting. A staple of most basic research in cancer involves the use of tissue culture plates, on which immortalized cell lines are grown in monolayers. However, this practice has been in use for over six decades and does not account for vital elements of the tumor microenvironment that are thought to aid in initiation, propagation, and ultimately, metastasis of cancer. Furthermore, information gleaned from these techniques does not always translate to animal models or, more crucially, clinical trials in cancer patients. Osteosarcoma (OS) and Ewing sarcoma (ES) are the most common primary tumors of bone, but outcomes for patients with metastatic or recurrent disease have stagnated in recent decades. The unique elements of the bone tumor microenvironment have been shown to play critical roles in the pathogenesis of these tumors and thus should be incorporated in the preclinical models of these diseases. In recent years, the field of tissue engineering has leveraged techniques used in designing scaffolds for regenerative medicine to engineer preclinical tumor models that incorporate spatiotemporal control of physical and biological elements. We herein review the clinical aspects of OS and ES, critical elements present in the sarcoma microenvironment, and engineering approaches to model the bone tumor microenvironment. Impact statement The current paradigm of cancer biology investigation and therapeutic testing relies heavily on monolayer, monoculture methods developed over half a century ago. However, these methods often lack essential hallmarks of the cancer microenvironment that contribute to tumor pathogenesis. Tissue engineers incorporate scaffolds, mechanical forces, cells, and bioactive signals into biological environments to drive cell phenotype. Investigators of bone sarcomas, aggressive tumors that often rob patients of decades of life, have begun to use tissue engineering techniques to devise in vitro models for these diseases. Their efforts highlight how critical elements of the cancer microenvironment directly affect tumor signaling and pathogenesis.

Mass spectrometry imaging of endogenous metabolites in response to doxorubicin in a novel 3D osteosarcoma cell culture model

Three-dimensional (3D) cell culture is a rapidly emerging field, which mimics some of the physiological conditions of human tissues. In cancer biology, it is considered a useful tool in predicting in vivo chemotherapy responses, compared with conventional two-dimensional (2D) cell culture. We have developed a novel 3D cell culture model of osteosarcoma composed of aggregated proliferative tumour spheroids, which shows regions of tumour heterogeneity formed by aggregated spheroids of polyclonal tumour cells. Aggregated spheroids show local necrotic and apoptotic regions and have sizes suitable for the study of spatial distribution of metabolites by mass spectrometry imaging (MSI). We have used this model to perform a proof-of-principle study showing a heterogeneous distribution of endogenous metabolites that colocalise with the necrotic core and apoptotic regions in this model. Cytotoxic chemotherapy (doxorubicin) responses were significantly attenuated in our 3D cell culture model compared with those of standard cell culture, as determined by resazurin assay, despite sufficient doxorubicin diffusion demonstrated by localisation throughout the 3D constructs. Finally, changes to the distribution of endogenous metabolites in response to doxorubicin were readily detected by MSI. Principal component analysis identified 50 metabolites which differed most in their abundance between treatment groups, and of these, 10 were identified by both in-software t test and mixed-effects analysis of variance (ANOVA). Subsequent independent MSIs of identified species were consistent with principle component analysis findings. This proof-of-principle study shows for the first time that chemotherapy-induced changes in metabolite abundance and distribution may be determined in 3D cell culture by MSI, highlighting this method as a potentially useful tool in the elucidation of chemotherapy responses as an alternative to in vivo testing.

Establishment and Characterization of a Recurrent Osteosarcoma Cell Line: OSA 1777

Osteosarcoma (OSA) is the most common primary bone malignancy overall and is responsible for considerable adolescent mortality. Approximately 850 patients are newly diagnosed with OSA in the United States each year. While the 5-year survival rate for localized OSA has improved from <20% over 40 years ago to over 65% today, progress has dwindled over the past three decades. Therapeutic stagnation has occurred, in part, as a result of limited preclinical models and the overall heterogeneity of OSA among patients. In this study, we report the establishment and characterization of a novel OSA cell line: OSA 1777. This cell line was isolated from the recurrent tumor specimen of a 19-year-old female who initially experienced 99% tumor necrosis after neoadjuvant chemotherapy and eventually had local recurrence and metastases. We present OSA 1777 growth characteristics, tumor markers, chemotherapeutic sensitivities, and oncogenic spheroid formation. In a two-dimensional (2D) monolayer culture, OSA 1777 exhibited a spindle shape and 60 h doubling time. STR DNA profiling revealed a unique genomic identity not matching any existing human cancer cell lines from the ATCC or DSMZ databases. Consistent with the mesenchymal origin, western blot was positive for vimentin and negative for the carcinoma marker cytokeratin. Within three-dimensional (3D) culture, the cells formed spheroids of similar patterning and smaller size compared with MNNG-HOS and U2OS cell lines. The chemotherapeutic drug sensitivity of OSA 1777 was evaluated in both 2D and 3D culture systems. In summary, we report OSA 1777 as a novel biological model of OSA amenable to future studies focused on OSA that recurs despite an initially strong chemotherapeutic response. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:902-910, 2020.

M, Donato S, Giordano E, Malucelli E, Iotti S. Analysis of Intracellular Magnesium and Mineral Depositions during Osteogenic Commitment of 3D Cultured Saos2 Cells

In this study, we explore the behaviour of intracellular magnesium during bone phenotype modulation in a 3D cell model built to mimic osteogenesis. In addition, we measured the amount of magnesium in the mineral depositions generated during osteogenic induction. A two-fold increase of intracellular magnesium content was found, both at three and seven days from the induction of differentiation. By X-ray microscopy, we characterized the morphology and chemical composition of the mineral depositions secreted by 3D cultured differentiated cells finding a marked co-localization of Mg with P at seven days of differentiation. This is the first experimental evidence on the presence of Mg in the mineral depositions generated during biomineralization, suggesting that Mg incorporation occurs during the bone forming process. In conclusion, this study on the one hand attests to an evident involvement of Mg in the process of cell differentiation, and, on the other hand, indicates that its multifaceted role needs further investigation.

Impact of Natural Dietary Agents on Multiple Myeloma Prevention and Treatment: Molecular Insights and Potential for Clinical Translation

Chemoprevention is based on the use of non-toxic, pharmacologically active agents to prevent tumor progression. In this regard, natural dietary agents have been described by the most recent literature as promising tools for controlling onset and progression of malignancies. Extensive research has been so far performed to shed light on the effects of natural products on tumor growth and survival, disclosing the most relevant signal transduction pathways targeted by such compounds. Overall, anti-inflammatory, anti-oxidant and cytotoxic effects of dietary agents on tumor cells are supported either by results from epidemiological or animal studies and even by clinical trials. Multiple myeloma is a hematologic malignancy characterized by abnormal proliferation of bone marrow plasma cells and subsequent hypercalcemia, renal dysfunction, anemia, or bone disease, which remains incurable despite novel emerging therapeutic strategies. Notably, increasing evidence supports the capability of dietary natural compounds to antagonize multiple myeloma growth in preclinical models of the disease, underscoring their potential as candidate anti-cancer agents. In this review, we aim at summarizing findings on the anti-tumor activity of dietary natural products, focusing on their molecular mechanisms, which include inhibition of oncogenic signal transduction pathways and/or epigenetic modulating effects, along with their potential clinical applications against multiple myeloma and its related bone disease.

Understanding and Modeling Metastasis Biology to Improve Therapeutic Strategies for Combating Osteosarcoma Progression

Osteosarcoma is a malignant primary tumor of bone, arising from transformed progenitor cells with osteoblastic differentiation and osteoid production. While categorized as a rare tumor, most patients diagnosed with osteosarcoma are adolescents in their second decade of life and underscores the potential for life changing consequences in this vulnerable population. In the setting of localized disease, conventional treatment for osteosarcoma affords a cure rate approaching 70%; however, survival for patients suffering from metastatic disease remain disappointing with only 20% of individuals being alive past 5 years post-diagnosis. In patients with incurable disease, pulmonary metastases remain the leading cause for osteosarcoma-associated mortality; yet identifying new strategies for combating metastatic progression remains at a scientific and clinical impasse, with no significant advancements for the past four decades. While there is resonating clinical urgency for newer and more effective treatment options for managing osteosarcoma metastases, the discovery of druggable targets and development of innovative therapies for inhibiting metastatic progression will require a deeper and more detailed understanding of osteosarcoma metastasis biology. Toward the goal of illuminating the processes involved in cancer metastasis, a convergent science approach inclusive of diverse disciplines spanning the biology and physical science domains can offer novel and synergistic perspectives, inventive, and sophisticated model systems, and disruptive experimental approaches that can accelerate the discovery and characterization of key processes operative during metastatic progression. Through the lens of trans-disciplinary research, the field of comparative oncology is uniquely positioned to advance new discoveries in metastasis biology toward impactful clinical translation through the inclusion of pet dogs diagnosed with metastatic osteosarcoma. Given the spontaneous course of osteosarcoma development in the context of real-time tumor microenvironmental cues and immune mechanisms, pet dogs are distinctively valuable in translational modeling given their faithful recapitulation of metastatic disease progression as occurs in humans. Pet dogs can be leveraged for the exploration of novel therapies that exploit tumor cell vulnerabilities, perturb local microenvironmental cues, and amplify immunologic recognition. In this capacity, pet dogs can serve as valuable corroborative models for realizing the science and best clinical practices necessary for understanding and combating osteosarcoma metastases.

Hydrogel 3D in vitro tumor models for screening cell aggregation mediated drug response

Hydrogel-based 3D in vitro models comprising tumor ECM-mimetic biomaterials exhibit differential responses to therapeutics according to cancer cells cellular aggregation state.

MiR-33a Controls hMSCS Osteoblast Commitment Modulating the Yap/Taz Expression Through EGFR Signaling Regulation

Mesenchymal stromal cells (hMSCs) display a pleiotropic function in bone regeneration. The signaling involved in osteoblast commitment is still not completely understood, and that determines the failure of current therapies being used. In our recent studies, we identified two miRNAs as regulators of hMSCs osteoblast differentiation driving hypoxia signaling and cytoskeletal reorganization. Other signalings involved in this process are epithelial to mesenchymal transition (EMT) and epidermal growth factor receptor (EGFR) signalings through the regulation of Yes-associated protein (YAP)/PDZ-binding motif (TAZ) expression. In the current study, we investigated the role of miR-33a family as a (i) modulator of YAP/TAZ expression and (ii) a regulator of EGFR signaling during osteoblast commitments. Starting from the observation on hMSCs and primary osteoblast cell lines (Nh-Ost) in which EMT genes and miR-33a displayed a specific expression, we performed a gain and loss of function study with miR-33a-5p and 3p on hMSCs cells and Nh-Ost. After 24 h of transfections, we evaluated the modulation of EMT and osteoblast genes expression by qRT-PCR, Western blot, and Osteoimage assays. Through bioinformatic analysis, we identified YAP as the putative target of miR-33a-3p. Its role was investigated by gain and loss of function studies with miR-33a-3p on hMSCs; qRT-PCR and Western blot analyses were also carried out. Finally, the possible role of EGFR signaling in YAP/TAZ modulation by miR-33a-3p expression was evaluated. Human MSCs were treated with EGF-2 and EGFR inhibitor for different time points, and qRT-PCR and Western blot analyses were performed. The above-mentioned methods revealed a balance between miR-33a-5p and miR-33a-3p expression during hMSCs osteoblast differentiation. The human MSCs phenotype was maintained by miR-33a-5p, while the maintenance of the osteoblast phenotype in the Nh-Ost cell model was permitted by miR-33a-3p expression, which regulated YAP/TAZ through the modulation of EGFR signaling. The inhibition of EGFR blocked the effects of miR-33a-3p on YAP/TAZ modulation, favoring the maintenance of hMSCs in a committed phenotype. A new possible personalized therapeutic approach to bone regeneration was discussed, which might be mediated by customizing delivery of miR-33a in simultaneously targeting EGFR and YAP signaling with combined use of drugs.

Osteomimetic matrix components alter cell migration and drug response in a 3D tumour-engineered osteosarcoma model

Osteosarcoma management continues to lack the appropriate prognostic tools to assign personalised treatment. This leaves non-responders to standard care vulnerable to recurring disease and pulmonary metastases. Developing 3D in vitro disease models to serve as a test bed for personalised treatment is a promising approach to address this issue. This study describes the generation of 3D osteosarcoma models termed "tumouroids", which are geometrically compartmentalised to reproduce the bone cancer mass and its surrounding. Although the tumour microenvironment impacts osteosarcoma in many ways, this model focussed on interrogating the influence of a biomimetic matrix on tumour cell behaviour. The 3D matrix was supplemented with the bone-marrow proteins laminin, fibronectin and NuOss® bone granules. This led to increased invasion of osteosarcoma cell aggregates from within the bone-like matrix into the surrounding acellular bone marrow-like ECM. The presence of bone granules also yielded an atypical molecular profile of osteosarcoma cells, suggesting malignant metabolic reprogramming. Changes include decreased MMP-9 (p < 0.05) and increased PTEN (p < 0.05), MCP-1 (p < 0.01) and MCT-4 (p < 0.05) gene expression. This complex 3D biomimetic composition also changed cellular responses to doxorubicin, a common chemotherapeutic agent used to treat osteosarcoma, and reproduced key issues of in vivo treatment like drug penetrance and doxorubicin-induced bone toxicity. This work highlights the importance of a biomimetic matrix in 3D osteosarcoma models for both basic and translational research. STATEMENT OF SIGNIFICANCE: This study describes the generation of 3D osteosarcoma models termed "tumouroids", which are geometrically compartmentalised to reproduce the bone cancer mass and its environment. Utilising this novel model, specific parameters of osteosarcoma growth and invasion were investigated. Osteosarcoma cell lines proliferate at a slower rate, exhibit malignant metabolic reprogramming, and respond to drug intervention at lower concentrations of doxorubicin hydrochloride in matrix-complex compared to basic tumouroids. As such, this study provides evidence that the tumour microenvironment impacts osteosarcoma in many ways. The osteosarcoma tumouroid described herein may form the basis of a personalised-medicine strategy, which will allow the testing of drug effectiveness similar to that used for antibiotic selection for pathogenic bacteria.

Improvement of osteogenic differentiation of human mesenchymal stem cells on composite poly l-lactic acid/nano-hydroxyapatite scaffolds for bone defect repair

Tissue engineering offers new approaches to repair bone defects, which cannot be repaired physiologically, developing scaffolds that mimic bone tissue architecture. Furthermore, biomechanical stimulation induced by bioreactor, provides biomechanical cues that regulate a wide range of cellular events especially required for cellular differentiation and function. The improvement of human mesenchymal stem cells (hMSCs) colonization in poly-l-lactic-acid (PLLA)/nano-hydroxyapatite (nHA) composite scaffold was evaluated in terms of cell proliferation (dsDNA content), bone differentiation (gene expression and protein synthesis) and ultrastructural analysis by comparing static (s3D) and dynamic (d3D) 3D culture conditions at 7 and 21 days. The colonization rate of hMSCs and osteogenic differentiation were amplified by d3D when physical stimulation was provided by a perfusion bioreactor. Increase in dsDNA content (p < 0.0005), up-regulation of RUNX2, ALPL, SPP1 (p < 0.0005) and SOX9 (p < 0.005) gene expression, and more calcium nodule formation (p < 0.0005) were observed in d3D cultures in comparison to s3D ones over time. Dynamic 3D culture, mimicking the mechanical signals of bone environment, improved significantly osteogenic differentiation of hMSCs on PLLA/nHA scaffold, without the addition of growth factors, confirming this composite scaffold suitable for bone regeneration.

New Advances in the Study of Bone Tumors: A Lesson From the 3D Environment

Bone primary tumors, such as osteosarcoma, are highly aggressive pediatric tumors that in 30% of the cases develop lung metastasis and are characterized by poor prognosis. Bone is also the third most common metastatic site in patients with advanced cancer and once tumor cells become homed to the skeleton, the disease is usually considered incurable, and treatment is only palliative. Bone sarcoma and bone metastasis share the same tissue microenvironment and niches. 3D cultures represent a new promising approach for the study of interactions between tumor cells and other cellular or acellular components of the tumor microenvironment (i.e., fibroblasts, mesenchymal stem cells, bone ECM). Indeed, 3D models can mimic physiological interactions that are crucial to modulate response to soluble paracrine factors, tumor drug resistance and aggressiveness and, in all, these innovative models might be able of bypassing the use of animal-based preclinical cancer models. To date, both static and dynamic 3D cell culture models have been shown to be particularly suited for screening of anticancer agents and might provide accurate information, translating in vitro cell cultures into precision medicine. In this mini-review, we will summarize the current state-of-the-art in the field of bone tumors, both primary and metastatic, illustrating the different methods and techniques employed to realize 3D cell culture systems and new results achieved in a field that paves the way toward personalized medicine.

Engineered mosaic protein polymers; a simple route to multifunctional biomaterials

BACKGROUND

Engineered living materials (ELMs) are an exciting new frontier, where living organisms create highly functional materials. In particular, protein ELMs have the advantage that their properties can be manipulated via simple molecular biology. Caf1 is a protein ELM that is especially attractive as a biomaterial on account of its unique combination of properties: bacterial cells export it as a massive, modular, non-covalent polymer which is resistant to thermal and chemical degradation and free from animal material. Moreover, it is biologically inert, allowing the bioactivity of each 15 kDa monomeric Caf1 subunit to be specifically engineered by mutagenesis and co-expressed in the same Escherichia coli cell to produce a mixture of bioactive Caf1 subunits.

RESULTS

Here, we show by gel electrophoresis and transmission electron microscopy that the bacterial cells combine these subunits into true mosaic heteropolymers. By combining two separate bioactive motifs in a single mosaic polymer we demonstrate its utility by stimulating the early stages of bone formation by primary human bone marrow stromal cells. Finally, using a synthetic biology approach, we engineer a mosaic of three components, demonstrating that Caf1 complexity depends solely upon the variety of monomers available.

CONCLUSIONS

These results demonstrate the utility of engineered Caf1 mosaic polymers as a simple route towards the production of multifunctional biomaterials that will be useful in biomedical applications such as 3D tissue culture and wound healing. Additionally, in situ Caf1 producing cells could create complex bacterial communities for biotechnology.

GRAPHICAL ABSTRACT

Multiplex quantitative analysis of stroma-mediated cancer cell invasion, matrix remodeling, and drug response in a 3D co-culture model of pancreatic tumor spheroids and stellate cells

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a stroma-rich carcinoma, and pancreatic stellate cells (PSCs) are a major component of this dense stroma. PSCs play significant roles in metastatic progression and chemoresistance through cross-talk with cancer cells. Preclinical in vitro tumor model of invasive phenotype should incorporate three-dimensional (3D) culture of cancer cells and PSCs in extracellular matrix (ECM) for clinical relevance and predictability.

METHODS

PANC-1 cells were cultured as tumor spheroids (TSs) using our previously developed minipillar chips, and co-cultured with PSCs, both embedded in collagen gels. Effects of PSC co-culture on ECM fiber network, invasive migration of cancer cells, and expression of epithelial-mesenchymal transition (EMT)-related proteins were examined. Conditioned media was also analyzed for secreted factors involved in cancer cell-PSC interactions. Inhibitory effect on cancer cell invasion was compared between gemcitabine and paclitaxel at an equitoxic concentration in PANC-1 TSs co-cultured with PSCs.

RESULTS

Co-culture condition was optimized for the growth of TSs, activation of PSCs, and their interaction. Increase in cancer cell invasion via ECM remodeling, invadopodia formation and EMT, as well as drug resistance was recapitulated in the TS-PSC co-culture, and appeared to be mediated by cancer cell-PSC interaction via multiple secreted factors, including IL-6, IL-8, IGF-1, EGF, TIMP-1, uPA, PAI-1, and TSP-1. Compared to gemcitabine, paclitaxel showed a greater anti-invasive activity, which was attributed to suppresion of invadopodia formation in cancer cells as well as to PSC-specific cytotoxicity abrogating its paracrine signaling.

CONCLUSIONS

Here, we established 3D co-culture of TSs of PANC-1 cells and PSCs using minipillar histochips as a novel tumoroid model of PDAC. Our results indicate usefulness of the present co-culture model and multiplex quantitative analysis method not only in studying the role of PSCs and their interactions with tumor cell towards metastatic progression, but also in the drug evaluation of stroma-targeting drugs.

Tissue engineered models of healthy and malignant human bone marrow

Tissue engineering is becoming increasingly successful in providing in vitro models of human tissues that can be used for ex vivo recapitulation of functional tissues as well as predictive testing of drug efficacy and safety. From simple tissue models to microphysiological platforms comprising multiple tissue types connected by vascular perfusion, these "tissues on a chip" are emerging as a fast track application for tissue engineering, with great potential for modeling diseases and supporting the development of new drugs and therapeutic targets. We focus here on tissue engineering of the hematopoietic stem and progenitor cell compartment and the malignancies that can develop in the human bone marrow. Our overall goal is to demonstrate the utility and interconnectedness of improvements in bioengineering methods developed in one area of bone marrow studies for the remaining, seemingly disparate, bone marrow fields.

Inhibitory effects of low intensity pulsed ultrasound on osteoclastogenesis induced in vitro by breast cancer cells

Background

Bone tissue is one of the main sites for breast metastasis; patients diagnosed with advanced breast cancer mostly develop bone metastasis characterized by severe osteolytic lesions, which heavily influence their life quality. Low Intensity Pulsed Ultrasound (LIPUS) is a form of mechanical energy able to modulate various molecular pathways both in cancer and in health cells.

The purpose of the present study was to evaluate for the first time, the ability of LIPUS to modulate osteolytic capability of breast cancer cells.

Methods

Two different approaches were employed: a) Indirect method -conditioned medium obtained by MDA-MB-231 cell line treated or untreated with LIPUS was used to induce osteoclast differentiation of murine macrophage Raw264.7 cell line; and b) Direct method -MDA-MB-231 were co-cultured with Raw264.7 cells and treated or untreated with LIPUS.

Results

LIPUS treatment impaired MDA-MB-231 cell dependentosteoclast differentiation and produced a reduction of osteoclast markers such as Cathepsin K, Matrix Metalloproteinase 9 and Tartrate Resistant Acid Phosphatase, suggesting its role as an effective and safe adjuvant in bone metastasis management.

Conclusion

LIPUS treatment could be a good and safety therapeutic adjuvant in osteolyitic bone metastasis not only for the induction properties of bone regeneration, but also for the reduction of osteolysis.