Antitumor and immunomodulatory activity of fucoidan from the brown alga Lessonia trabeculata (Lessoniaceae) on breast cancer spheroids / Actividad antitumoral e inmunomoduladora de fucoidan del alga parda Lessonia trabeculata (Lessoniaceae) en esferoides de cáncer de mama

Abstract Introduction: The therapeutic benefits of the brown algae fucoidan in the treatment of breast cancer have attracted considerable interest in recent years. However, research using spheroids which provide relevant results in trials for antitumor and immunomodulatory products because they adequately simulate the tumor microenvironment, is limited. Objective: To evaluate the antitumor and immunomodulatory activity of Lessonia trabeculata fucoidan (LtF), native to the Peruvian Sea, on two types of multicellular tumor spheroids. Methods: The study was conducted from January to December 2021. Two types of spheroides were elaborated: from 4T1 tumor cells (MTS), and from 4T1 tumor cells+mouse splenocytes (MTSs). The antitumor activity of LtF was evaluated in MTS by quantifying cell viability with MTT. Immunomodulatory activity was determined in MTSs using the IC50 for two types of treatment: simple, fucoidan alone (LtF) and combined, fucoidan+doxorubicin (LtF+Dox). Pro-inflammatory (TNF-α, IL-6) and anti-inflammatory (IL-10, TGF-β) cytokine production was quantified by sandwich ELISA 72 h after treatment. Dox was used as positive control in all assays. Results: LtF exerted antitumor activity as evidenced by increased necrotic zone and cell debris formation compared to the untreated control. Antitumor activity was concentration dependent between 100 and 6 000 μg/ml. In MTSs, simple treatment increased IL-6 and decreased IL-10 and TGF-β production. The combined treatment significantly reduced TGF-β production. In both treatments and Dox, there was an increase in IL-6 compared to the untreated control. The highest production of IL-10 and TGF-β was observed in the untreated control, compatible with a highly immunosuppressive tumor microenvironment. Conclusions: LtF is a good candidate for the treatment of breast cancer and can immunomodulate the tumor microenvironment alone or in combination with Dox.

Resumen Introduccción: Los beneficios terapéuticos del fucoidan de algas pardas en el tratamiento del cáncer de mama han despertado gran interés en los últimos años. Sin embargo, las investigaciones con esferoides son limitadas, éstos proporcionan resultados relevantes en ensayos de productos antitumorales e inmunomoduladores porque simulan adecuadamente el microambiente tumoral. Objetivo: Evaluar la actividad antitumoral e inmunomoduladora del fucoidan de Lessonia trabeculata (LtF), nativa del Mar Peruano, en dos tipos de esferoides tumorales multicelulares. Métodos: El estudio se realizó de enero a diciembre de 2021. Se elaboraron dos tipos de esferoides: con células tumorales 4T1 (MTS) y con células tumorales 4T1+esplenocitos de ratón (MTSs). La actividad antitumoral de LtF se evaluó en MTS cuantificando la viabilidad celular con MTT. La inmunomodulación se determinó en MTSs utilizando la IC50 para dos tipos de tratamiento: simple, fucoidan solo (LtF) y combinado, fucoidan+doxorubicina (LtF+Dox). La producción de citoquinas proinflamatorias (TNF-α, IL-6) y antiinflamatorias (IL-10, TGF-β) se cuantificó mediante ELISA sándwich 72 h post-tratamiento. En todos los ensayos se utilizó Dox como control positivo. Resultados: En los MTS, el LtF ejerció actividad antitumoral evidenciada por aumento de la zona necrótica y formación de restos celulares respecto al control no tratado. La actividad antitumoral fue concentración-dependiente entre 100 y 6 000 μg/ml. En los MTSs, con el tratamiento simple se incrementó IL-6 y disminuyeron IL-10 y TGF-β. El tratamiento combinado redujo significativamente la producción de TGF-β. Los dos tratamientos y Dox incrementaron IL-6 respecto al control no tratado. La mayor producción de IL-10 y TGF-β se observó en los no tratados, compatible con un microambiente tumoral altamente inmunosupresor. Conclusiones: El LtF es un buen candidato para tratar el cáncer de mama y puede inmunomodular el microambiente tumoral solo o en combinación con Dox.

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.

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.

mRNAs biomarker related to the control of proliferation and cell death in HepG2/C3A spheroid and monolayer cultures treated with piperlongumine

Background: Cell culture (spheroid and 2D monolayer cultures) is an essential tool in drug discovery. Piperlongumine (PLN), a naturally occurring alkaloid present in the long pepper (Piper longum), has been implicated in the regulation of GSTP1 activity. In vitro treatment of cancer cells with PLN increases ROS (reactive oxygen species) levels and induces cell death, but its molecular mode of action has not been entirely elucidated. Methods: In this study, we correlated the antiproliferative effects (2D and 3D cultures) of PLN (CAS 20069­09-4, Sigma-Aldrich) with morphological and molecular analyses in HepG2/C3A cell line. We performed assays for cytotoxicity (MTT), comet assays for genotoxicity, induction of apoptosis, analysis of the cell cycle phase, and analysis of the membrane integrity by flow cytometry. Relative expression of mRNA of genes related to proliferation, apoptosis, cell cycle control, metabolism of xenobiotics, and reticulum endoplasmic stress. Results: PLN reduced the cell proliferation by the cell cycle arrest in G2/M. Changes in the mRNA expression for CDKN1A (4.9x) and CCNA2 (0.5x) of cell cycle control genes were observed. Cell death occurred due to apoptosis, which may have been induced by increased expression of proapoptotic mRNAs (BAK1, 3.1x; BBC3, 2.4x), and by an increase in 9 and 3/7 active caspases. PLN induced cellular injury by ROS generation and DNA damage. DNA damage induced MDM2 signaling (3.0x) associated with the appearance of the monastral spindle in mitosis. Genes associated with ROS degradation also showed increased mRNA expression (GSR, 2.0x; SOD1, 2.1x). PLN induce endoplasmic reticulum stress with the increase in the mRNA expression of ERN1 (4.5x) and HSPA14 (2.2x). The xenobiotic metabolism showed increased mRNA expression for CYP1A2 (2.2x) and CYP3A4 (3.4x). In addition to 2D culture, PLN treatment also inhibited the growth of 3D culture (spheroids). Conclusion: Thus, the findings of our study show that several gene expression biomarkers (mRNAs) and monastral spindle formation indicated the many pathways of damage induced by PLN treatment that contributes to its antiproliferative effects

Proton NMR characterization of intact primary and metastatic melanoma cells in 2D & 3D cultures

OBJECTIVE: To characterize the differences between the primary and metastatic melanoma cell lines grown in 2D cultures and 3D cultures. METHODS: Primary melanoma cells (WM115) and metastatic melanoma cells (WM266) extracted from a single donor was cultured in 2D as well as 3D cultures. These cells were characterized using proton NMR spectrometry, and the qualitative chemical shifts markers were identified and discussed. RESULTS: In monolayer culture (2D), we observed one qualitative chemical shift marker for primary melanoma cells. In spheroid cultures (3D), we observed nine significant chemical shifts, of which eight markers were specific for primary melanoma spheroids, whereas the other one marker was specific to metastatic melanoma spheroids. This study suggests that the glucose accumulation and phospholipid composition vary significantly between the primary and metastatic cells lines that are obtained from a single donor and also with the cell culturing methods. 14 qualitative chemical shift markers were obtained in the comparison between monolayer culture and spheroids cultures irrespective of the differences in the cell lines. Among which 4 were unique to monolayer cultures whereas 10 chemical shifts were unique to the spheroid cultures. This study also shows that the method of cell culture would drastically affect the phospholipid composition of the cells and also depicts that the cells in spheroid culture closely resembles the cells in vivo. CONCLUSION: This study shows the high specificity of proton NMR spectrometry in characterizing cancer cell lines and also shows the variations in the glucose accumulation and phospholipid composition between the primary and metastatic melanoma cell lines from the same donor. Differences in the cell culture method does plays an important role in phospholipid composition of the cells.

Increased circulating macrophage migration inhibitory factor levels are associated with coronary artery disease

BACKGROUND: To evaluate the macrophage migration inhibitory factor and E-selectin levels in patients with acute coronary syndrome. MATERIALS/METHODS: We examined the plasma migration inhibitory factor and E-selectin levels in 87 patients who presented with chest pain at our hospital. The patients were classified into two groups according to their cardiac status. Sixty-five patients had acute myocardial infarction, and 22 patients had non-cardiac chest pain (non-coronary disease). We designated the latter group of patients as the control group. The patients who presented with acute myocardial infarction were further divided into two subgroups: ST-elevated myocardial infarction (n = 30) and non-ST elevated myocardial infarction (n = 35). RESULTS: We found higher plasma migration inhibitory factor levels in both acute myocardial infarction subgroups than in the control group. However, the E-selectin levels were similar between the acute myocardial infarction and control patients. In addition, we did not find a significant difference in the plasma migration inhibitory factor levels between the ST elevated myocardial infarction and NST-elevated myocardial infarction subgroups. DISCUSSION: The circulating concentrations of migration inhibitory factor were significantly increased in acute myocardial infarction patients, whereas the soluble E-selectin levels were similar between acute myocardial infarction patients and control subjects. Our results suggest that migration inhibitory factor may play a role in the atherosclerotic process. .

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.

Cultivation and identification of colon cancer stem cell-derived spheres from the Colo205 cell line

Our group established a method to culture spheres under serum-free culture condition. However, the biological characteristics and the tumorigenicity of spheres are unknown. Here, we demonstrate that sphere cells expressed high levels of the putative colorectal cancer stem cell markers CD133 and CD44. The CD133-positive rates were 13.27 ± 5.62, 52.71 ± 16.97 and 16.47 ± 2.45 percent in sphere cells, regular Colo205 cells and differentiated sphere cells, respectively, while the CD44-positive rates were 62.92 ± 8.38, 79.06 ± 12.10 and 47.80 ± 2.5 percent, respectively, and the CD133/CD44-double-positive rates were 10.77 ± 4.96, 46.89 ± 19.17 and 12.41 ± 2.27 percent, respectively (P < 0.05). Cancer sphere cells formed crypt-like structures in 3-D culture. Moreover, cells from cancer spheres exhibited more tumorigenicity than regular Colo205 cells in a xenograft assay. The cancer sphere cells displayed much higher oncogenicity than regular Colo205 cells to initiate neoplasms, as assayed by H&E staining, Musashi-1 staining and electron microscopy. Our findings indicated that the sphere cells were enriched with cancer stem cells (CSCs), and exhibited more proliferation capacity, more differentiation potential and especially more tumorigenicity than regular Colo205 cells in vitro and in vivo. Further isolation and characterization of these CSCs may provide new insights for novel therapeutic targets and prognostic markers.

A quantitative assessment of the morphological characteristics of BeWo cells as an in vitro model of human trophoblast cells / Una evaluación cuantitativa de las características morfológicas de las células BeWo como un modelo in vitro de las células de trofoblasto humano

In order to study the detailed morphology of trophoblast cells during human implantation, BeWo cells were cultured as spheroids in suspension culture. These cultures were then processed for light and electron microscopical examination. The present study showed that the BeWo spheroids consist of two cell types which are cytotrophoblast-like and syncytiotrophoblast-like. The cells with larger nuclear diameter made up only about 1 percent of the cell population and appear to be those of syncytiotrophoblast. Therefore the predominant cell type of the BeWo spheroids appeared to be relatively undifferentiated and cytotrophoblast-like. About 10 percent of the BeWo cells in the present study were mitotic, indicating a highly proliferative population. Total cell number increased about 12 times during the culture period from 107 +/- 9 on day 1 to 1211 +/- 145 on day 7 whereas the volume per cell increased about 2 times, from 1300 um3 on day 1 to 2400 um3 on day 7. Therefore overall growth of BeWo spheroids is due to both hyperplasia and hypertrophy. However, it appears that cell proliferation outstrips volumetric growth. These quantitative data show that BeWo cells grow mainly by hyperplasia and provide baseline values for further studies. In addition, the results show that BeWo cell morphology has marked similarities to that reported for human trophoblast, making it a useful model for subsequent in vitro studies.

En un cultivo de suspensión se estudió la morfología de las células durante la implantación del trofoblasto humano, células BeWo. Estos cultivos fueron procesados y examinados a través de microscopía de luz y electrónica. El estudio mostró que los esferoides BeWo constan de dos tipos de células, citotrofoblasto y sincitiotrofoblasto. Las células con mayor diámetro nuclear parecen ser los sincitiotrofoblasto que representaban sólo el 1 por ciento de la población celular. Por tanto, el tipo celular predominante de los esferoides BeWo parecían ser relativamente indiferenciados como citotrofoblasto. Alrededor del 10 por ciento de las células BeWo fueron mitóticas, lo que indica una población altamente proliferativa. El número de células totales aumentó alrededor de 12 veces durante el período de cultivo de 107 +/- 9 días en el día 1 a 1211 +/- 145 en el día 7, mientras que el volumen de la célula creció alrededor de 2 veces, desde 1300 mm3 el día 1 hasta 2400 mm3 el día 7. Por lo tanto, el crecimiento global de esferoides BeWo se debe tanto a la hiperplasia como a la hipertrofia. Sin embargo, parece que la proliferación celular supera al crecimiento volumétrico. Estos datos cuantitativos muestran que las células BeWo crecen principalmente por hiperplasia y proporcionan valores de referencia para estudios posteriores. Además, los resultados muestran que la morfología celular BeWo ha marcado similitudes con los reportado para el trofoblasto humano, por lo que es un modelo útil para posteriores estudios in vitro.

Análisis de la polaridad estructural y funcional de estructuras tridimensionales (esferoides) de células hepáticas porcinas cultivadas in vitro / Structural and functional polarity of porcine hepatocyte cultured spheroids

Los hepatocitos son células epiteliales polarizadas que, al ser aisladas y cultivadas, pierden la polaridad y las propiedades de célula diferenciada. El cultivo de células hepáticas como esferoides permite obtener estructuras con organización de tipo tisular. En este trabajo se analizó estructural y funcionalmente la polaridad de esferoides porcinos. Para ello, las células hepáticas porcinas fueron aisladas y cultivadas en agitación constante. La actividad metabólica de los esferoides fue probada mediante el metabolismo de diazepam y de amonio, así como con síntesis de albúmina. Sus características estructurales mostraron la polaridad de las células. Fueron observados paquetes de fibras de colágeno distribuidas irregularmente y fibras reticulares en formahomogénea en todo el volumen del esferoide. Se hallaron células Ck19+ formando estructuras tipo ducto biliar, así como también _ y _-cateninas y pan-cadherinas en diferentes zonas, especialmente en las laminas externas, con características de epitelio cuboidal. Por microscopía electrónica de barrido se observaron estructuras muy compactas con superficie lisa, y por microscopía electrónica de transmisión, canalículos biliares con microvellosidades, uniones tight, zonula adherens y desmosomas. Las organelas celulares como mitocondrias, núcleos, nucleolos, peroxisomas, retículo endoplásmico estaban bien conservadas. Una compleja red de canalículos biliares fue observada mediante la incorporación y excreción de un análogo de sal biliar fluorescente. El análisis de los ácidos biliares excretados mostró un patrón normal. La morfología y funcionalidad de los esferoides puede aportar un modelo apropiado para aplicaciones en las que es primordial mantener las funciones específicas del hígado, como un dispositivo de hígado bioartificial.

Hepatocytes are epithelial cells that show a complex polarity in vivo. However, hepatocytes isolated and cultured in vitro normally lose both their differentiated properties and polarity. Culturing hepatocyte spheroids seems to be the accurate approach to maintain tissue level of organization. The structural and functional polaritiesof pig liver spheroids were analyzed in this work. Swine liver cells were isolated and cultured as spheroids. Their metabolic activity was proved through the metabolism of diazepam, ammonium and synthesis of albumin. Several structural features show the presence of polarity in the cells inside the spheroids. Reticular and collagen fibers, as well as Ck19(+) cells forming duct-like structures were found. _eta and _-catenins and pancadherins were positive in different regions of the spheroids, mainly in the outer cell layers, which have cuboidal epithelia features. The scanning electron microscopy showed a tightly compacted architecture, with smooth surface. The transmission electron microscopy analysis showed bile canaliculi with microvilli, tight junctions, zonula adherens and desmosome-like junctions. Wellmaintained cellular organelles, as mitochondria, nucleus,nucleolus, peroxisomes, endoplasmic reticulum, were seen in the spheroids. A complex inner bile canaliculinetwork was shown by using a fluorescent bile acid analogue incorporated and excreted by the spheroids. Furthermore, excretion of a normal pattern of bile acids was demonstrated. The morphology and functionality of the spheroids may provide an appropriate model for applications where the maintenance of liver-specific functions is crucial, as a bioartificial liver device.

Multicellular spheroids of bone marrow stromal cells: a three-dimensional in vitro culture system for the study of hematopoietic cell migration

Cell fate decisions are governed by a complex interplay between cell-autonomous signals and stimuli from the surrounding tissue. In vivo cells are connected to their neighbors and to the extracellular matrix forming a complex three-dimensional (3-D) microenvironment that is not reproduced in conventional in vitro systems. A large body of evidence indicates that mechanical tension applied to the cytoskeleton controls cell proliferation, differentiation and migration, suggesting that 3-D in vitro culture systems that mimic the in vivo situation would reveal biological subtleties. In hematopoietic tissues, the microenvironment plays a crucial role in stem and progenitor cell survival, differentiation, proliferation, and migration. In adults, hematopoiesis takes place inside the bone marrow cavity where hematopoietic cells are intimately associated with a specialized three 3-D scaffold of stromal cell surfaces and extracellular matrix that comprise specific niches. The relationship between hematopoietic cells and their niches is highly dynamic. Under steady-state conditions, hematopoietic cells migrate within the marrow cavity and circulate in the bloodstream. The mechanisms underlying hematopoietic stem/progenitor cell homing and mobilization have been studied in animal models, since conventional two-dimensional (2-D) bone marrow cell cultures do not reproduce the complex 3-D environment. In this review, we will highlight some of the mechanisms controlling hematopoietic cell migration and 3-D culture systems.

Resistance of multicellular aggregates to pharmorubicin observed in human hepatocarcinoma cells

The objective of the present study was to investigate the multicellular resistance of human hepatocarcinoma cells BEL-7402 to pharmorubicin. Cells (1 x 10(4)) and 200 microcarrier Cytodex-3 beads were seeded onto a 24-well plate and cultured in RPMI 1640 medium. After the formation of multicellular aggregates, morphology and cell viability were analyzed by scanning electron microscopy, transmission electron microscopy and flow cytometry, respectively. The IC50 was determined by flow cytometry and MTT assay after the cells cultured in aggregates and monolayers were treated with pharmorubicin. The culture products exhibited structural characteristics somewhat similar to those of trabecular hepatocarcinoma in vivo. Among the microcarriers, cells were organized into several layers. Intercellular spaces were 0.5-2.0 æm wide and filled with many microvilli. The percent of viable cells was 87 percent. The cells cultured as multicellular aggregates were resistant to pharmorubicin with IC50 4.5-fold and 7.7-fold that of monolayer culture as determined by flow cytometry and MTT assay, respectively. This three-dimensional culture model may be used to investigate the mechanisms of multicellular drug resistance of hepatocarcinoma and to screen new anticancer drugs