Patient-Derived Organoids as a Promising Tool for Multimodal Management of Sarcomas.

The management of sarcomas, a diverse group of cancers arising from connective tissues, presents significant challenges due to their heterogeneity and limited treatment options. Patient-derived sarcoma organoids (PDSOs) have emerged as a promising tool in the multimodal management of sarcomas, offering unprecedented opportunities for personalized medicine and improved treatment strategies. This review aims to explore the potential of PDSOs as a promising tool for multimodal management of sarcomas. We discuss the establishment and characterization of PDSOs, which realistically recapitulate the complexity and heterogeneity of the original tumor, providing a platform for genetic and molecular fidelity, histological resemblance, and functional characterization. Additionally, we discuss the applications of PDSOs in pathological and genetic evaluation, treatment screening and development, and personalized multimodal management. One significant advancement of PDSOs lies in their ability to guide personalized treatment decisions, enabling clinicians to assess the response and efficacy of different therapies in a patient-specific manner. Through continued research and development, PDSOs hold the potential to revolutionize sarcoma management and drive advancements in personalized medicine, biomarker discovery, preclinical modeling, and therapy optimization. The integration of PDSOs into clinical practice can ultimately improve patient outcomes and significantly impact the field of sarcoma treatment.

Influence of Cellular Microenvironment on Human Articular Chondrocyte Cell Signaling.

OBJECTIVE: Alteration of the cellular microenvironment may influence the intra- and intercellular communication and contribute to cartilage injury and repair. The purpose of this study was to investigate how matrix elasticity/stiffness affects chondrogenic activities, including cell survival, phenotypic expression, and the release of both pro- and anti-inflammatory cytokines. DESIGN: Human articular chondrocytes (HACs) cultured on traditional 2-dimensional (2D) plastic surfaces were compared with those cultured within 3D hydrogel matrices of varying stiffness. Chondrogenic proliferation, differentiation, and the expression of pro- and anti-inflammatory cytokines were evaluated. Both interleukin-1-beta (IL-1ß) and human synovial fluid-derived cells (hSFCs) were introduced to study the effects of matrix stiffness on chondrocyte response. RESULTS: Cells demonstrated the most robust chondrogenic differentiation and secreted the least pro-inflammatory cytokines when the matrix stiffness was close to their native microenvironment. The IL-1ß effects were attenuated when HACs were co-cultured with hSFCs. CONCLUSION: Modifying the matrix stiffness to mimic the native cartilage microenvironment not only optimized chondrogenic expression but also was essential for the regulation of physiological homeostasis. This study proposed a new toolkit to study cell-molecule, cell-cell, and cell-matrix influence on cartilage physiology.

From competency to dormancy: a 3D model to study cancer cells and drug responsiveness.

BACKGROUND: The heterogeneous and dynamic tumor microenvironment has significant impact on cancer cell proliferation, invasion, drug response, and is probably associated with entering dormancy and recurrence. However, these complex settings are hard to recapitulate in vitro. METHODS: In this study, we mimic different restriction forces that tumor cells are exposed to using a physiologically relevant 3D model with tunable mechanical stiffness. RESULTS: Breast cancer MDA-MB-231, colon cancer HCT-116 and pancreatic cancer CFPAC cells embedded in the stiffer gels exhibit a changed morphology and cluster formation, prolonged doubling time, and a slower metabolism rate, recapitulating the pathway from competency to dormancy. Altering environmental restriction allows them to re-enter and exit dormant conditions and change their sensitivities to drugs such as paclitaxol and gemcitabine. Cells surviving drug treatments can still regain competent growth and form tumors in vivo. CONCLUSION: We have successfully developed an in vitro 3D model to mimic the effects of matrix restriction on tumor cells and this high throughput model can be used to study tumor cellular functions and their drug responses in their different states. This all in one platform may aid effective drug development.

Tumor bioengineering using a transglutaminase crosslinked hydrogel.

Development of a physiologically relevant 3D model system for cancer research and drug development is a current challenge. We have adopted a 3D culture system based on a transglutaminase-crosslinked gelatin gel (Col-Tgel) to mimic the tumor 3D microenvironment. The system has several unique advantages over other alternatives including presenting cell-matrix interaction sites from collagen-derived peptides, geometry-initiated multicellular tumor spheroids, and metabolic gradients in the tumor microenvironment. Also it provides a controllable wide spectrum of gel stiffness for mechanical signals, and technical compatibility with imaging based screening due to its transparent properties. In addition, the Col-Tgel provides a cure-in-situ delivery vehicle for tumor xenograft formation in animals enhancing tumor cell uptake rate. Overall, this distinctive 3D system could offer a platform to more accurately mimic in vivo situations to study tumor formation and progression both in vitro and in vivo.

The synergetic effect of hydrogel stiffness and growth factor on osteogenic differentiation.

Cells respond to various chemical signals as well as environmental aspects of the extracellular matrix (ECM) that may alter cellular structures and functions. Hence, better understanding of the mechanical stimuli of the matrix is essential for creating an adjuvant material that mimics the physiological environment to support cell growth and differentiation, and control the release of the growth factor. In this study, we utilized the property of transglutaminase cross-linked gelatin (TG-Gel), where modification of the mechanical properties of TG-Gel can be easily achieved by tuning the concentration of gelatin. Modifying one or more of the material parameters will result in changes of the cellular responses, including different phenotype-specific gene expressions and functional differentiations. In this study, stiffer TG-Gels itself facilitated focal contact formation and osteogenic differentiation while soft TG-Gel promoted cell proliferation. We also evaluated the interactions between a stimulating factor (i.e. BMP-2) and matrix rigidity on osteogenesis both in vitro and in vivo. The results presented in this study suggest that the interactions of chemical and physical factors in ECM scaffolds may work synergistically to enhance bone regeneration.

Injectable gel graft for bone defect repair.

AIM: To examine the performance of an injectable gel graft made of transglutaminase (Tg)-crosslinked gelatin gel with BMP-2 (BMP-2-Tg-Gel) for bone defect repair in animal models. MATERIALS & METHODS: BMP-2 mixed with gelatin gel was crosslinked using Tg. The release of tethered BMP-2 through autocrine and paracrine pathways was demonstrated by using C2C12 and NIH 3T3 cells, respectively. BMP-2-Tg-Gel was injected into the induced cranial defect site. After 14 days, the sample was removed for x-ray imaging and histological evaluation. RESULTS: Our in vivo results demonstrated that the injectable Tg-Gel with its osteoconductivity and controllable BMP-2 activity induced bone formation in our rat models when tethered with BMP-2. CONCLUSION: Tg-Gel as an injectable functional bone graft may enable the use of minimally invasive surgical procedures to treat irregular-shaped bone defects. Furthermore, this novel approach is capable of incorporating and controlling the release of therapeutic agents that may advance the science of tissue regeneration.