Spontaneous spheroids from alveolar bone-derived mesenchymal stromal cells maintain pluripotency of stem cells by regulating hypoxia-inducible factors

BACKGROUND: Spontaneous spheroid culture is a novel three-dimensional (3D) culture strategy for the rapid and efficient selection of progenitor cells. The objectives of this study are to investigate the pluripotency and differentiation capability of spontaneous spheroids from alveolar bone-derived mesenchymal stromal cells (AB-MSCs); compare the advantages of spontaneous spheroids to those of mechanical spheroids; and explore the mechanisms of stemness enhancement during spheroid formation from two-dimensional (2D) cultured cells. METHODS: AB-MSCs were isolated from the alveolar bones of C57BL/6 J mice. Spontaneous spheroids formed in low-adherence specific culture plates. The stemness, proliferation, and multi-differentiation capacities of spheroids and monolayer cultures were investigated by reverse transcription quantitative polymerase chain reaction (RT-qPCR), immunofluorescence, alkaline phosphatase (ALP) activity, and oil-red O staining. The pluripotency difference between the spontaneous and mechanical spheroids was analyzed using RT-qPCR. Hypoxia-inducible factor (HIFs) inhibition experiments were performed to explore the mechanisms of stemness maintenance in AB-MSC spheroids. RESULTS: AB-MSCs successfully formed spontaneous spheroids after 24 h. AB-MSC spheroids were positive for MSC markers and pluripotency markers (Oct4, KLF4, Sox2, and cMyc). Spheroids showed higher Ki67 expression and lower Caspase3 expression at 24 h. Under the corresponding conditions, the spheroids were successfully differentiated into osteogenic and adipogenic lineages. AB-MSC spheroids can induce neural-like cells after neurogenic differentiation. Higher expression of osteogenic markers, adipogenic markers, and neurogenic markers (NF-M, NeuN, and GFAP) was found in spheroids than in the monolayer. Spontaneous spheroids exhibited higher stemness than mechanical spheroids did. HIF-1α and HIF-2α were remarkably upregulated in spheroids. After HIF-1/2α-specific inhibition, spheroid formation was significantly reduced. Moreover, the expression of the pluripotency genes was suppressed. CONCLUSIONS: Spontaneous spheroids from AB-MSCs enhance stemness and pluripotency. HIF-1/2α plays an important role in the stemness regulation of spheroids. AB-MSC spheroids exhibit excellent multi-differentiation capability, which may be a potent therapy for craniomaxillofacial tissue regeneration.

Cellulose nanofibril matrix drives the dynamic formation of spheroids / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Multicellular spheroids, which mimic the natural organ counterparts, allow the prospect of drug screening and regenerative medicine. However, their application is hampered by low processing efficiency or limited scale. This study introduces an efficient method to drive rapid multicellular spheroid formation by a cellulose nanofibril matrix. This matrix enables the facilitated growth of spheroids (within 48 h) through multiple cell assembly into size-controllable aggregates with well-organized physiological microstructure. The efficiency, dimension, and conformation of the as-formed spheroids depend on the concentration of extracellular nanofibrils, the number of assembled cells, and the heterogeneity of cell types. The above strategy allows the robust formation mechanism of compacted tumoroids and hepatocyte spheroids.

3D spheroid cell cultures and their role in bone regeneration: a systematic review / Cultivos de esferoides 3D y su papel en la regeneración ósea: una revisión sistemática

Abstract Recently, the 3D spheroid cell culture application has been extensively used in the treatment of bone defects. A wide variety of methodologies have been used, which has made the comparison of results complex. Therefore, this systematic review has two aims: (i) to perform an analysis focused on the role of 3D spheroid cell culture in bone regeneration strategies; and (ii) address the main challenges in clinical application. A search of the following keywords "3D cell culture", "spheroid", and "bone regeneration" was carried out in the PubMed, Scopus, and ScienceDirect databases and limited to the years 2010-2020. Studies were included if their primary objective was the behavior of cell aggregates to formed spheroids structures by different 3D cell culture techniques focused on the regeneration of bone tissue. To address the risk of bias for in vitro studies, the United States national toxicology program tool was applied, and descriptive statistics of the data were performed, with the SPSS V.22 program. A total of 16 studies were included, which met the established criteria corresponding to in vitro and in vitro/in vivo studies; most of these studies used stem cells for the 3D cell spheroids. The most often methods used for the 3D formation were low adherence surface and rotational methods, moreover, mesenchymal stem cells were the cell line most frequently used because of their regenerative potential in the field of bone tissue engineering. Although the advances in research on the potential use of 3D spheroids in bone regeneration have made great strides, the constant innovation in cell spheroid formation methodologies means that clinical application remains in the future as strategy for 3D tissue bioprinting.

Resumen Recientemente, la aplicación del cultivo 3D de esferoides se ha utilizado ampliamente en el tratamiento de defectos óseos. La variedad de metodologías para lograr los cultivos 3D de esferoides ha hecho compleja la comparación de resultados. Por tanto, esta revisión sistemática tiene dos objetivos: (i) realizar un análisis centrado en el papel de los cultivos 3D de esferoides en las estrategias de regeneración ósea; y (ii) abordar los principales desafíos en la aplicación clínica. Se realizó una búsqueda de las siguientes palabras clave "cultivo celular 3D", "esferoide" y "regeneración ósea" en las bases de datos PubMed, Scopus y ScienceDirect y se limitó a los años 2010-2020. Se incluyeron los estudios si su principal objetivo era el comportamiento de agregados celulares para generar las estructuras esferoidales desarrollados por diferentes técnicas de cultivo celular 3D enfocadas a la regeneración del tejido óseo. Para abordar el riesgo de sesgo de los estudios in vitro, se aplicó la herramienta del programa nacional de toxicología de Estados Unidos y se realizaron estadísticas descriptivas de los datos, con el programa SPSS V.22. Se incluyeron un total de 16 estudios, que cumplieron con los criterios establecidos correspondientes a estudios in vitro e in vitro/in vivo; la mayoría de estos estudios utilizaron células troncales para generar los esferoides celulares 3D. Los métodos más utilizados para la formación de los esferoides 3D fueron la superficie de baja adherencia y los métodos de rotación, asimismo, la línea celular de células troncales mesenquimales fueron las más utilizadas debido a su gran potencial regenerativo en el campo de la ingeniería de tejidos óseos. Aunque los avances en la investigación sobre el uso potencial de los cultivos celulares de esferoides 3D en la regeneración ósea han logrado grandes avances, la constante innovación en las metodologías de la generación de esferoides 3D deja claro que la aplicación clínica de estos permanecerá en el futuro como estrategia en la bioimpresión tisular.

Expression and regulation of keratin 6B in CD44+ bladder cancer stem cells / 中国组织工程研究

BACKGROUND: Bladder cancer stem cells could promote the recurrence and drug resistance of bladder cancer. Numerous studies have shown that keratin 6B (KRT6B) is involved in the production and progression of tumors, and is closely related to the prognosis of tumors. OBJECTIVE: To observe the expression of keratin 6B in CD44+ bladder cancer stem cells and to show the influence of keratin 6B on proliferation, migration, and self-renewal of bladder cancer stem cells, and to further explore the effect of keratin 6B expression on the prognosis of bladder cancer patients. METHODS: (1) CD44+ 5637 bladder cancer stem cells were isolated by magnetic active cell sorting. Cancer stem cell-related gene expression of SOX2, OCT4, and NANOG was detected via real-time polymerase chain reaction. The spheroid formation assay was used to detect the ability of self-renewal of cancer stem cells in CD44+ cells. Keratin 6B expression was detected in CD44+ bladder cancer stem cells by real-time polymerase chain reaction. (2) The CD44+5637 bladder cancer stem cells were divided into two groups. In the keratin 6B siRNA group, keratin 6B small interfering RNA was transfected into CD44+ bladder cancer stem cells. Untransfected CD44+ bladder cancer stem cells were used as the black control group. Cells were collected at 2 days post-transfection. The proliferation, migration, and self-renewal capacity of keratin 6B siRNA CD44+ bladder cancer stem cells were detected by the colony and wound healing assay and spheroid formation respectively. (3) Totally 24 bladder cancer tissues were used by immunohistochemistry to analyze the expression of CD44v6 and keratin 6B. (4) ONCOMINE database was used to analyze the effect of keratin 6B expression on the overall survival of bladder cancer. RESULTS AND CONCLUSION: (1) Cancer stem cell-related genes (SOX2, OCT4, NANOG) and keratin 6B expression was higher in CD44+ cells isolated by magnetic active cell sorting compared with CD44- cells (P < 0.05). Cell proliferation, migration, and in vitro spheroid formation were significantly increased (P < 0.05). Keratin 6B small interfering RNA down-regulated the expression of keratin 6B in CD44+ bladder cancer stem cells (P < 0.05). (2) Compared with the blank control group, the proliferation and migration of CD44+ bladder cancer stem cells after transfection of keratin 6B small interfering RNA (P < 0.05), and the number of tumorsphere significantly diminished (P < 0.05); the expression of Notch1 and Hes1 mRNA increased (P < 0.05). (3) Keratin 6B and CD44v6 were significantly different in bladder cancer tissue (P=0.006). The overall survival rate of bladder cancer patients with high expression of keratin 6B was lower than that of patients with low expression of keratin 6B. (4) The results showed that keratin 6B was highly expressed in CD44+ bladder cancer stem cells, and could promote the proliferation, migration, and self-renewal capacity of bladder cancer stem cells. The high expression of keratin 6B contributes to improving the survival of bladder cancer patients.

Study of mass spectrometry imaging metabolomics of paclitaxel based on esophageal cancer multicellular tumor spheroids cultured in vitro / 药学学报

Multicellular tumor spheroids (MCTS) can simulate the structure and metabolic characteristics of tumors in vivo, which is of great significance to study the metabolic phenotype of tumor cells and the mechanism of drug intervention. In this study, esophageal cancer MCTS were constructed, and MCTS frozen sections were prepared after treated with different formulations of paclitaxel (PTX) including common PTX injection, PTX liposome and albumin bound PTX. MCTS mass spectrometry imaging analysis method was established by using air flow assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI). The visualization of the permeation and enrichment process of PTX in MCTs after PTX treatment was realized, and the spatially resolved metabolomics of PTX injection group was studied. The results showed that the permeation and enrichment behavior of PTX in MCTs model were related to the formulations. The changes of endogenous metabolites in MCTs of esophageal cancer after treated with PTX injection had temporal and spatial characteristics. The metabolic changes of MCTS during the initial 0-4 hours were dominated by the down-regulation of middle-high polarity metabolites and some lipids in the central region of MCTS, while the metabolic changes of MCTS during 8-72 hours were mainly up-regulated by lipid metabolites in the peripheral region of MCTS. The combination of in vivo tumor-associated MCTs model with label free, highly sensitive and high coverage mass spectrometry imaging technology provided a new method and strategy for the study of pharmacometabolomics.

Melanocyte spheroids are formed by repetitive long-term trypsinization

Background: Autologous melanocyte transplantation plays an important role in the treatment of vitiligo. Objective: Previous studies have indicated that, compared with melanocytes growing in monolayers, melanocyte spheroids have a better survival in growth factor- and serum-deprived conditions. Methods: Melanocyte spheroids were obtained from human epidermis by repetitive long-term trypsinization and maintained an aggregated morphology for a short period in certain conditions. Results: Melanocyte spheroids were capable of growing into normal dendritic melanocytes in monolayer when they were harvested and reinoculated in 24-well plates. Immunohistochemical analysis of the melanocyte spheroids revealed that they were positive for HMB45, a melanosome-specific marker. No melanomas occurred when melanocyte spheroids were transplanted into mice. Conclusion: Our study provides a promising approach for melanocyte transplantation to treat vitiligo.

Three-Dimensional Spheroid Formation of Cryopreserved Human Dental Follicle-Derived Stem Cells Enhances Pluripotency and Osteogenic Induction Properties

BACKGROUND: Enhancement and maintenance of the stemness of mesenchymal stem cells (MSCs) is one of the most important factors contributing to the successful in vivo therapeutic application of these cells. In this regard, three-dimensional (3D) spheroid formation has been developed as reliable method for increasing the pluripotency of MSCs. Moreover, using a new protocol, we have previously shown that dental tissues of extracted wisdom teeth can be effectively cryopreserved for subsequent use as a source of autologous stem cells. The main purpose of this study is to analyze the stemness and in vitro osteogenic differentiation potential of 3D spheroid dental MSCs compared with conventional monolayer cultured MSCs. METHODS: In this study, MSC-characterized stem cells were isolated and cultured from long-term cryopreserved dental follicles (hDFSCs), and then 2D hDFSCs were cultured under 3D spheroid-forming conditions using a newly designed microchip dish. The spheroids (3D hDFSCs) thus produced were investigated and characterized with respect to stemness, MSC marker expression, apoptosis, cell cycle analysis, extracellular matrix (ECM) production, and osteogenic and adipogenic differentiation properties. RESULTS: In terms of MSC and senescence markers, spheroid cells showed no difference when compared with 2D hDFSCs; however, 3D hDFSCs were observed to have a higher proportion of cell cycle arrest and a larger number of apoptotic cells. Moreover, spheroids showed substantially increased levels of pluripotency marker (early transcription factors) and ECM protein expression. Compared with 2D hDFSCs, there was also a notable enhancement in the osteogenic induction potential of spheroids, although no differences were observed with respect to in vitro adipogenesis. CONCLUSION: To the best of our knowledge, this is the first study to demonstrate the application of a spheroid culture system for dental follicle-derived stem cells using a microchip dish. Although further studies are needed, including in vivo transplantation, the results obtained in this study indicate that spheroid hDFSCs derived from cryopreserved dental follicle tissues could be used as a valuable source of autologous stem cells for bone tissue regeneration.

Advances in the application of three-dimensional tumor spheroids model in the mechanism study of drug resistance / 中国药科大学学报

@#In comparison with the traditional two-dimensional tumor cell culture, the three-dimensional tumor spheroid culture can not only provide with an in vivo-like growth environment for tumor cells, but also maintain maximum cell activities. Therefore, the three-dimensional tumor spheroid culture is widely used in oncology research. In particular, the three-dimensional tumor cells retain the material and structural basis of the microenvironment of tumor in vivo, which is closer to the actual physiological environment, allowing it to be an ideal in vitro model for evaluating the tumor treatment response and drug resistance in tumors. This review summarizes the mechanisms of drug resistance in three-dimensional tumor cells, especially those induced by the morphology and microenvironment of three-dimensional tumor spheres, and puts forward the problems existing in the current three-dimensional tumor cells model, as well as the future development direction.

Spheroid Culture of Mammalian Olfactory Receptor Neurons: Potential Applications for a Bioelectronic Nose

The olfactory system can detect many odorants with high sensitivity and selectivity based on the expression of nearly a thousand types of olfactory receptors (ORs) in olfactory receptor neurons (ORNs). These ORs have a dynamic odorant detection range and contribute to signal encoding processes in the olfactory bulb (OB). To harness the capabilities of the olfactory system and develop a biomimetic sensor, stable culture and maintenance of ORNs are required. However, in vitro monolayer culture models have several key limitations: i) short available period of cultured neurons, ii) low cultural efficiency, and iii) long-term storage challenges. This study aims to develop a technique: i) to support the spheroid culture of primary ORN precursors facilitating stable maintenance and long-term storage, and ii) to demonstrate the viability of ORN spheroid culture in developing an olfactory system mimetic bioelectronic nose. Recombinant protein (REP; TGPG[VGRGD(VGVPG)₆]₂₀WPC) was used to form the ORN spheroids. Spheroid formation enabled preservation of primary cultured ORNs without a significant decrease in viability or the expression of stemness markers for ten days. Physiological characteristics of the ORNs were verified by monitoring intracellular calcium concentration upon odorant mixture stimulation; response upon odorant stimulation were observed at least for ten days in these cultivated ORNs differentiated from spheroids. Coupling ORNs with multi electrode array (MEA) enabled the detection and discrimination of odorants by analyzing the electrical signal patterns generated following odorant stimulation. Taken together, the ORN spheroid culture process is a promising technique for the development of a bioelectronic nose and high-throughput odorant screening device.

Three-Dimensional Spheroid Culture Increases Exosome Secretion from Mesenchymal Stem Cells

BACKGROUND: Mass production of exosomes is a prerequisite for their commercial utilization. This study investigated whether three-dimensional (3D) spheroid culture of mesenchymal stem cells (MSCs) could improve the production efficiency of exosomes and if so, what was the mechanism involved. METHODS: We adopted two models of 3D spheroid culture using the hanging-drop (3D-HD) and poly(2-hydroxyethyl methacrylate) (poly-HEMA) coating methods (3D-PH). The efficiency of exosome production from MSCs in the 3D spheroids was compared with that of monolayer culture in various conditions. We then investigated the mechanism of the 3D spheroid culture-induced increase in exosome production. RESULTS: The 3D-HD formed a single larger spheroid, while the 3D-PH formed multiple smaller ones. However, MSCs cultured on both types of spheroids produced significantly more exosomes than those cultured in conventional monolayer culture (2D). We then investigated the cause of the increased exosome production in terms of hypoxia within the 3D spheroids, high cell density, and non-adherent cell morphology. With increasing spheroid size, the efficiency of exosome production was the largest with the least amount of cells in both 3D-HD and 3D-PH. An increase in cell density in 2D culture (2D-H) was less efficient in exosome production than the conventional, lower cell density, 2D culture. Finally, when cells were plated at normal density on the poly-HEMA coated spheroids (3D-N-PH); they formed small aggregates of less than 10 cells and still produced more exosomes than those in the 2D culture when plated at the same density. We also found that the expression of F-actin was markedly reduced in the 3D-N-PH culture. CONCLUSION: These results suggested that 3D spheroid culture produces more exosomes than 2D culture and the non-adherent round cell morphology itself might be a causative factor. The result of the present study could provide useful information to develop an optimal process for the mass production of exosomes.

Two-Cell Spheroid Angiogenesis Assay System Using Both Endothelial Colony Forming Cells and Mesenchymal Stem Cells

Most angiogenesis assays are performed using endothelial cells. However, blood vessels are composed of two cell types: endothelial cells and pericytes. Thus, co-culture of two vascular cells should be employed to evaluate angiogenic properties. Here, we developed an in vitro 3-dimensional angiogenesis assay system using spheroids formed by two human vascular precursors: endothelial colony forming cells (ECFCs) and mesenchymal stem cells (MSCs). ECFCs, MSCs, or ECFCs+MSCs were cultured to form spheroids. Sprout formation from each spheroid was observed for 24 h by real-time cell recorder. Sprout number and length were higher in ECFC+MSC spheroids than ECFC-only spheroids. No sprouts were observed in MSC-only spheroids. Sprout formation by ECFC spheroids was increased by treatment with vascular endothelial growth factor (VEGF) or combination of VEGF and fibroblast growth factor-2 (FGF-2). Interestingly, there was no further increase in sprout formation by ECFC+MSC spheroids in response to VEGF or VEGF+FGF-2, suggesting that MSCs stimulate sprout formation by ECFCs. Immuno-fluorescent labeling technique revealed that MSCs surrounded ECFC-mediated sprout structures. We tested vatalanib, VEGF inhibitor, using ECFC and ECFC+MSC spheroids. Vatalanib significantly inhibited sprout formation in both spheroids. Of note, the IC₅₀ of vatalanib in ECFC+MSC spheroids at 24 h was 4.0 ± 0.40 μM, which are more correlated with the data of previous animal studies when compared with ECFC spheroids (0.2 ± 0.03 μM). These results suggest that ECFC+MSC spheroids generate physiologically relevant sprout structures composed of two types of vascular cells, and will be an effective pre-clinical in vitro assay model to evaluate pro- or anti-angiogenic property.

Preparation of hispidulin chitosan microsphere and its antiproliferation effect / 中国中药杂志

Hispidulin(HPDL) chitosan microspheres were prepared in this study to deliver HPDL to the lesion sitevia intravenous injection, and further evaluate their anticancer effects in vitro and the growth inhibition effect on A549 cells spheroids. HPDL chitosan microspheres were prepared by emulsion crosslinking method with chitosan as a drug carrier and the amount of HPDL was determined by high performance liquid chromatography (HPLC). The morphology of microspheres was observed under laser scanning confocal microscope. Additionally, the drug release amount of targeting microspheres was detected by dialysis method. Furthermore, the anti-proliferative effects against A549 lung cancer cells were tested by sulforhodamine B (SRB) method, and the effects of HPDL chitosan micrpsphereson early apoptosis of A549 cellswere determined by flow cytometry. A549 cells tumor spheroids were developed in vitro and then HPDL chitosan microspheres were added. On the 0, 1, 3, 7 d after adding the drugs, the inverted microscope was used to observe the mythologicaland volume changes of A549 cells spheroids. The encapsulation efficiency of HPDL chitosan microspheres was （75.32±0.52）%, and the drug loading amount was （7.76±0.67）%. Meanwhile, the microspheres were round shaped andhad smooth surface. The HPDL chitosan microspheres exhibited stronger inhibitory effects on A549 lung cancer cells. The results of flow cytometry indicated that, the early apoptosis rate of lung cancer A549 cells was （37.0±0.75）% at 24 h cells culture after drug administration. The volume of tumor spheroid was significantly inhibited, which had been shrunk by (50.09±11.06)% after the treatment by drug-loaded microsphere at day 7 as compared with blank group; meanwhile, the cells surface were obviously lysed. The preparation method in this research was simple and practicable, and the microspheres prepared with this method were round and smooth, with high encapsulation efficiency, which can significantly inhibit proliferation of lung adenocarcinoma A549 cells and induce cell apoptosis, and at the same time can cause lysisand death of A549 cell tumor spheroid.

Aberrant Activation of Cdc2/cyclin B1 Is Involved in Initiation of Cytoskeletal Pathology in Murine Niemann-Pick Disease Type C / 华中科技大学学报（医学）（英德文版）

Niemann-Pick disease type C (NPC) is a fatal,neurovisceral lipid storage disease,neuropathologically characterized by cytoplasmic sequestration of glycolipids in neurons,progressive neuronal loss,neurofibrillary tangles (NFTs) formation,and axonal spheroids (AS).Cytoskeletal pathology including accumulation of hyperphosphorylated cytoskeletal proteins is a neuropathological hallmark of the mouse model of NPC (npc mice).With a goal of elucidating the mechanisms underlying the lesion formation,we investigated the temporal and spatial characteristics of cytoskeletal lesions and the roles of cdc2,cdk4,and cdk5 in lesion formation in young npc mice.Cytoskeletal lesions were detectable in npc mice at three weeks of age.Importantly,concomitant activation of cdc2/cyclin B 1 kinase and accumulation of a subsequently generated cohort of phospho-epitopes were detected.The activation of cdk4/cyclin D1 and cdk5/p25 kinases was observed during the fourth week of life in npc mice,and this activation contributed to the lesion formation.We concluded that the progression of cytoskeletal pathology in npc mice older than four weeks is accelerated by the cumulative effect of cdc2,cdk4,and cdk5 activation.Furthermore,cdc2/cyclin B1 may act as a key initial player one week earlier.Targeting cell cycle activation may be beneficial to slow down the NPC pathogenesis.

Long-Duration Three-Dimensional Spheroid Culture Promotes Angiogenic Activities of Adipose-Derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) offer significant therapeutic promise for various regenerative therapies. However, MSC-based therapy for injury exhibits low efficacy due to the pathological environment in target tissues and the differences between in vitro and in vivo conditions. To address this issue, we developed adipose-derived MSC spheroids as a novel delivery method to preserve the stem cell microenvironment. MSC spheroids were generated by suspension culture for 3 days, and their sizes increased in a time-dependent manner. After re-attachment of MSC spheroids to the plastic dish, their adhesion capacity and morphology were not altered. MSC spheroids showed enhanced production of hypoxia-induced angiogenic cytokines such as vascular endothelial growth factor (VEGF), stromal cell derived factor (SDF), and hepatocyte growth factor (HGF). In addition, spheroid culture promoted the preservation of extracellular matrix (ECM) components, such as laminin and fibronectin, in a culture time- and spheroid size-dependent manner. Furthermore, phosphorylation of AKT, a cell survival signal, was significantly higher and the expression of pro-apoptotic molecules, poly (ADP ribose) polymerase-1 (PARP-1) and cleaved caspase-3, was markedly lower in the spheroids than in MSCs in monolayers. In the murine hindlimb ischemia model, transplanted MSC spheroids showed better proliferation than MSCs in monolayer. These findings suggest that MSC spheroids promote MSC bioactivities via secretion of angiogenic cytokines, preservation of ECM components, and regulation of apoptotic signals. Therefore, MSC spheroid-based cell therapy may serve as a simple and effective strategy for regenerative medicine.

LY294002 decreases the proliferation of cancer stem cell-enriched spheroid cells from human hepatocel-lular carcinoma via inhibiting of PI3K-Akt signaling pathway / 国际肿瘤学杂志

Objective To investigate the impact of LY294002 on the proliferation of cancer stem cell-enriched spheroid cells from human hepatocellular carcinoma via regulating phosphatidylinositol-3-kinaseprotein kinase B(PI3K-Akt)signaling pathway. Methods The cancer stem cell-enriched spheroid cells were genera-ted by culturing HepG2 cells in serum-free medium. LY294002(10,20,30 μmol/ L),an inhibitor of PI3K-Akt signaling pathway,was used in the experimental groups,without used in the control group. The impact of LY294002 on the spheroid cells proliferation was confirmed by cell counting kit(CCK-8 kit). The expression of Akt was tested by Western blotting. The expression of PI3K-Akt signaling pathway downstream genes such as decoy receptor 3(DcR3),mammalian target of rapamycin(mTOR),B-cell lymphoma(Bcl)-2 and Cyclin D1 were tested by real-time PCR. Results 30 μmol/ L LY294002 could inhibit the proliferation of spheroid cells, and significant difference in the absorbance(A value)was observed between the experimental group and control group[(0. 14 ± 0. 03)vs(0. 56 ± 0. 01),t = - 8. 915,P = 0. 000]. The expression level of phosphorylated Akt protein increased[(0. 57 ± 0. 08)vs(0. 16 ± 0. 42),t = 6. 027,P = 0. 026]. The mRNA of DcR3 [(0. 38 ± 0. 08)vs 1,t = 13. 060,P = 0. 006],mTOR[(0. 37 ± 0. 04)vs 1,t = 30. 363,P = 0. 001],Bcl-2 [(0. 26 ± 0. 04)vs 1,t = 33. 554,P = 0. 001]and Cyclin D1[(0. 10 ± 0. 02)vs 1,t = 63. 528,P = 0. 000] decreased. Conclusion LY294002 could inhibit the proliferation of cancer stem cell-enriched spheroid cells from human hepatocellular carcinoma via inhibiting PI3K-Akt signaling pathway.

The viability and property of rabbit corneal endothelial cells by spheroid culture / 中华实验眼科杂志

Background The construction of tissue-engineered corneal endothelium and corneal endothelial cells (CECs) therapy need abundant seed cells,so how to culture a large amount of CECs with high viability and original cell properties is an urgent issue to be solved.Objective This study was to establish three-dimensional spheroid culture of CECs and explore the cellular biological characteristics.Methods Primary rabbit CECs were isolated with trypsin and subcultured.Low attachment and shaking culture was applied to form CECs spheres.Cultured cells were identified under the inverted microscope.The surface features of the cells were examined under the scanning electron microscope.The viability of the cells were assayed by acridine orange (AO) staining and CCK-8 kit.Then CECs spheres were incubated to 6-well plate for 1 week,and immunofluorescence staining was used to identify the expression of zonula occludens-1 (ZO-1) and Na+/K+-ATPase in the cells.The cell proliferation value of spheroid culture method was compared with that of regular culture method.Results CECs grew into aggregation after cultured with the hexagonal or polygonal shape and tight connection among the cells.The cells converged into single layer and slabstone-like arrangement 1 week later.Cells migrated out of the CECs sphere and formed an uneven spherical surface.The living cells showed green fluorescence for AO with the survival rate 90％.The absorbance (A450) of the cells was 1.524±0.013 and 1.265 ±0.021 in the spherical culture group and conventional culture group,respectively,showing a significant difference between them (t =-3.436,P=0.010).The positive cells of ZO-1 and Na+/K+-ATPase showed the green fluorescence for FITC on cell membrane and blue fluorescence for DAPI on cell nucleus.Conclusions Spherical culture method maintains a high viability and proliferation ability of the cells and remains phenotype of CECs,which is superior to conventional culture method.This culture method provides better seeding CECs for the establishment of tissue engineering cornea endothelial layer and CECs therapy.

A spheroid-based 3-D culture model for pancreatic cancer drug testing, using the acid phosphatase assay

Current therapy for pancreatic cancer is multimodal, involving surgery and chemotherapy. However, development of pancreatic cancer therapies requires a thorough evaluation of drug efficacy in vitro before animal testing and subsequent clinical trials. Compared to two-dimensional culture of cell monolayer, three-dimensional (3-D) models more closely mimic native tissues, since the tumor microenvironment established in 3-D models often plays a significant role in cancer progression and cellular responses to the drugs. Accumulating evidence has highlighted the benefits of 3-D in vitro models of various cancers. In the present study, we have developed a spheroid-based, 3-D culture of pancreatic cancer cell lines MIAPaCa-2 and PANC-1 for pancreatic drug testing, using the acid phosphatase assay. Drug efficacy testing showed that spheroids had much higher drug resistance than monolayers. This model, which is characteristically reproducible and easy and offers rapid handling, is the preferred choice for filling the gap between monolayer cell cultures and in vivo models in the process of drug development and testing for pancreatic cancer.

Comparison of the effect of epigenetical treatment in 2D and 3D cholangiocarcinoma tumor models / 中华肝胆外科杂志

Objective To investigate the effects of epigenetic drugs on 2D- and 3D-cultured cholangiocarcinoma cells in vitro.Methods In this study,we have built compact and round TFK-1 spheroid in poly-HEMA coated 96-well plate and determined the effects of epigenetical drugs on 2D and 3D cultured cholangiocarcinoma cells:TFK-1.Viability of 2D and 3D cells model was examined by WST assay and FDA/PI staining. Using methylation-specific PCR analysis,we demonstrated the changes of methylation status of promoters regarding three tumor suppressor genes APC,E-Cadherin,and p16 INK4A.Results The average diameters of compact and round TFK-1 spheroids were in the range of 350-400 μm.The TFK-1 spheroid cells were more resistant to the epigenetic drugs and demonstrated a 11.2155-fold higher IC50 values for hydralazine and valproic acid than the same cells grown as monolayer. Higher doses of epigenetic drugs were needed to reverse the hypermethylation status in 3D cultured cells than 2D cells; however,the parallel dosage - dependent characteristic did not show in the 3D spheroid group.Conclusions Taken together,we established a 3D culture model of human cholangiocarcinoma epithelial spheroid.The 3D spheroid cells are more complex than the 2D monolayer cells and their unique characteristics are able to affect the consequences of epigenetic therapy.The 3D spheroid is a promising model for the research of epigenetic therapy.

Biological properties of colon cancer spheroid cells cultured in serum-free medium / 中华消化外科杂志

Objective To obtain colon cancer spheroid cells from human colon cancer cell lines cultured in serum-free medium (SFM),and investigate the proliferative and migratory properties of colon cancer spheroid cells.Methods Human colon cancer cell lines HCT116 and HT29 were cultured in SFM,and then the generation of spheroid cells was observed.The expression of stem cell surface marker CD133 was detected by flow cytometry,and the proliferative and migratory properties of colon cancer spheroid cells were detected by cell counting kit-8 and Transwell migration assay,respectively.All data were analyzed by using the t test.Results Spheroid cells were obtained from colon cancer cell lines HCT116 and HT29 in SFM.The ratios of spheroid cells with positive expression of CD133 generated by HCT116 and HT29 were 75.44％ ± 11.41％ and 76.22％ ± 14.23％,respectively.Compared with original colon cancer cells cultured in serum supplemented medium,the number of HCT116 and HT29 spheroid cells with positive expression of CD133 was significantly greater (t =11.43,9.17,P ＜ 0.05 ),and the proliferative and migratory abilities were much stronger also.Conclusion Colon cancer spheroid cells cultured in SFM have higher positive expression of CD133 and stronger proliferative and migratory abilities,and it can be utilized as a feasible model for further studies of colonic stem cells.

Preparation and application of multicellular spheroid in cancer therapy / 基础医学与临床

Multicellular spheroid (MCS) can simulate many aspects of the in vivo physiological and pathological conditions in many aspects,better reflect the in-vivo behavior of cells in tumors.So it's increasingly accepted as a valuable tool for evaluating the efficacy of therapeutic intervention including chemotherapy,radiotherapy,immunotherapy and combined therapy.Various spheroid co-culture approaches have been presented to study heterologous cells interaction in solid tumors.The present review briefly introduces the methodology and applications of MCS with focus on the up-to-date information.