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Rodrigues DB, Moreira HR, Jarnalo M, Horta R, Marques AP, Reis RL, Pirraco RP. Generation of 3D melanoma models using an assembloid-based approach. Acta Biomater 2024; 178:93-110. [PMID: 38382833 DOI: 10.1016/j.actbio.2024.02.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 01/31/2024] [Accepted: 02/13/2024] [Indexed: 02/23/2024]
Abstract
While 3D tumor models have greatly evolved over the past years, there is still a strong requirement for more biosimilar models which are capable of recapitulating cellular crosstalk within the tumor microenvironment while equally displaying representative levels of tumor aggressiveness and invasion. Herein, we disclose an assembloid melanoma model based on the fusion of individual stromal multicellular spheroids (MCSs). In contrast to more traditional tumor models, we show that it is possible to develop self-organizing, heterotypic melanoma models where tumor cells present stem-cell like features like up-regulated pluripotency master regulators SOX2, POU5F1 and NANOG. Additionally, these assembloids display high levels of invasiveness while embedded in 3D matrices as evidenced by stromal cell promotion of melanoma cell invasion via metalloproteinase production. Furthermore, sensitivity to anticancer drug doxorubicin was demonstrated for the melanoma assembloid model. These findings suggest that melanoma assembloids may play a significant role in the field of 3D cancer models as they more closely mimic the tumor microenvironment when compared to more traditional MCSs, opening the doors to a better understanding of the role of tumor microenvironment in supporting tumor progression. STATEMENT OF SIGNIFICANCE: The development of complex 3D tumor models that better recapitulate the tumor microenvironment is crucial for both an improved comprehension of intercellular crosstalk and for more efficient drug screening. We have herein developed a self-organizing heterotypic assembloid-based melanoma model capable of closely mimicking the tumor microenvironment. Key features recapitulated were the preservation of cancer cell stemness, sensitivity to anti-cancer agents and tumor cell invasion promoted by stromal cells. The approach of pre-establishing distinct stromal domains for subsequent combination into more complex tumor constructs provides a route for developing superior tumor models with a higher degree of similarity to native cancer tissues.
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Affiliation(s)
- Daniel B Rodrigues
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco, Guimarães, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga, Guimarães 4805-017, Portugal
| | - Helena R Moreira
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco, Guimarães, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga, Guimarães 4805-017, Portugal
| | - Mariana Jarnalo
- Department of Plastic and Reconstructive Surgery, and Burn Unity, Centro Hospitalar de São João, Porto, Portugal; Faculty of Medicine - University of Porto, Portugal
| | - Ricardo Horta
- Department of Plastic and Reconstructive Surgery, and Burn Unity, Centro Hospitalar de São João, Porto, Portugal; Faculty of Medicine - University of Porto, Portugal
| | - Alexandra P Marques
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco, Guimarães, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga, Guimarães 4805-017, Portugal
| | - Rui L Reis
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco, Guimarães, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga, Guimarães 4805-017, Portugal
| | - Rogério P Pirraco
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco, Guimarães, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga, Guimarães 4805-017, Portugal.
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Roberge CL, Miceli RT, Murphy LR, Kingsley DM, Gross RA, Corr DT. Sophorolipid Candidates Demonstrate Cytotoxic Efficacy against 2D and 3D Breast Cancer Models. JOURNAL OF NATURAL PRODUCTS 2023; 86:1159-1170. [PMID: 37104545 PMCID: PMC10760934 DOI: 10.1021/acs.jnatprod.2c00804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Sophorolipids are biosurfactants derived from the nonpathogenic yeasts such as Starmerella bombicola with potential efficacy in anticancer applications. Simple and cost-effective synthesis of these drugs makes them a promising alternative to traditional chemotherapeutics, pending their success in preliminary drug-screening. Drug-screening typically utilizes 2D cell monolayers due to their simplicity and ease of high-throughput assessment. However, 2D assays fail to capture the complexity and 3D context of the tumor microenvironment and have consequently been implicated in the high percentage of drugs investigated in vitro that later fail in clinical trials. Herein, we screened two sophorolipid candidates and a clinically-used chemotherapeutic, doxorubicin, on in vitro breast cancer models ranging from 2D monolayers to 3D spheroids, employing optical coherence tomography to confirm these morphologies. We calculated corresponding IC50 values for these drugs and found one of the sophorolipids to have comparable toxicities to the chemotherapeutic control. Our findings show increased drug resistance associated with model dimensionality, such that all drugs tested showed that 3D spheroids exhibited higher IC50 values than their 2D counterparts. These findings demonstrate promising preliminary data to support the use of sophorolipids as a more affordable alternative to traditional clinical interventions and demonstrate the importance of 3D tumor models in assessing drug response.
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Affiliation(s)
- Cassandra L Roberge
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Rebecca T Miceli
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Lillian R Murphy
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - David M Kingsley
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Richard A Gross
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - David T Corr
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
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3
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Alsadi N, Mallet JF, Matar C. miRNA-200b Signature in the Prevention of Skin Cancer Stem Cells by Polyphenol-enriched Blueberry Preparation. J Cancer Prev 2021; 26:162-173. [PMID: 34703819 PMCID: PMC8511576 DOI: 10.15430/jcp.2021.26.3.162] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/18/2021] [Accepted: 09/23/2021] [Indexed: 12/24/2022] Open
Abstract
Exposure of the skin to solar UV radiation leads to inflammation, DNA damage, and dysregulation of cellular signaling pathways, which may cause skin cancer. Photochemoprevention with natural products is an effective strategy for the control of cutaneous neoplasia. Polyphenols have been proven to help prevent skin cancer and to inhibit the growth of cancer stem cells (CSCs) through epigenetic mechanisms, including modulation of microRNAs expression. Thus, the current study aimed to assess the effect of polyphenol enriched blueberry preparation (PEBP) or non-fermented blueberry juice (NBJ) on expression of miRNAs and target proteins associated with different clinicopathological characteristics of skin cancer such as stemness, motility, and invasiveness. We observed that PEBP significantly inhibited the proliferation of skin CSCs derived from different melanoma cell lines, HS 294T and B16F10. Moreover, PEBP was able to reduce the formation of melanophores. We also showed that the expression of the CD133+ stem cell marker in B16F10 and HS294T cell lines was significantly decreased after treating the cells with PEBP in comparison to the NBJ and control groups. Importantly, tumor suppressors' miR-200s, involved in the regulation of the epithelial-to-mesenchymal transition and metastasis, were strikingly upregulated. In addition, we have shown that a protein target of the tumor suppressor miR200b, ZEB1, was also significantly modulated. Thus, the results demonstrates that PEBP possesses potent anticancer and anti-metastatic potentials and may represent a novel chemopreventative agent against skin cancer.
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Affiliation(s)
- Nawal Alsadi
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Canada
| | - Jean-François Mallet
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Canada
| | - Chantal Matar
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Canada.,Department of Nutrition Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
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4
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Concentration-Dependent Pro- and Antitumor Activities of Quercetin in Human Melanoma Spheroids: Comparative Analysis of 2D and 3D Cell Culture Models. Molecules 2021; 26:molecules26030717. [PMID: 33573155 PMCID: PMC7866537 DOI: 10.3390/molecules26030717] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 01/06/2023] Open
Abstract
Quercetin, a dietary flavonoid found in fruits and vegetables, has been described as a substance with many anti-cancer properties in a variety of preclinical investigations. In the present study, we demonstrate that 2D and 3D melanoma models exhibit not only different sensitivities to quercetin, but also opposite, cancer-promoting effects when metastatic melanoma spheroids are treated with quercetin. Higher concentrations of quercetin reduce melanoma growth in three tested cell lines, whereas low concentrations induce the opposite effect in metastatic melanoma spheroids but not in the non-metastatic cell line. High (>12.5 µM) or low (<6.3 µM) quercetin concentrations decrease or enhance cell viability, spheroid size, and cell proliferation, respectively. Additionally, melanoma cells cultivated in 2D already show significant caspase 3 activity at very low concentrations (>0.4 µM), whereas in 3D spheroids apoptotic cells, caspase 3 activity can only be detected in concentrations ≥12.5 µM. Further, we show that the tumor promoting or repressing effect in the 3D metastatic melanoma spheroids are likely to be elicited by a precisely controlled regulation of Nrf2/ARE-mediated cytoprotective genes, as well as ERK and NF-κB phosphorylation. According to the results obtained here, further studies are needed to better characterize the mechanisms of action underlying the pro- and anti-carcinogenic effects of quercetin on human melanomas.
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Fu J, Li XB, Wang LX, Lv XH, Lu Z, Wang F, Xia Q, Yu L, Li CM. One-Step Dip-Coating-Fabricated Core-Shell Silk Fibroin Rice Paper Fibrous Scaffolds for 3D Tumor Spheroid Formation. ACS APPLIED BIO MATERIALS 2020; 3:7462-7471. [PMID: 35019488 DOI: 10.1021/acsabm.0c00679] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Bioscaffolds are important substrates for supporting three-dimensional (3D) cell cultures. Silk fibroin (SF) is an attractive biomaterial in tissue engineering because of its good biocompatibility and mechanical properties. Electrospinning is one of the most often used approaches to fabricate SF fibrous scaffolds; yet, this technique still faces many challenges, such as low yield, residual organic solvents, limited extensibility of fibers, and a lack of spatial control over pore size. To circumvent these limitations, a core-shell SF on rice paper (SF@RP) fibrous scaffold was fabricated using a mild one-step dip-coating method. The cellulose fiber matrix of RP is the physical basis of the 3D scaffold, whereas the SF coating on the cellulose fiber controls the adhesion/spreading of the cells. The results indicated that by tuning the secondary structure of SF on the surface of a SF@RP scaffold, the cell behavior on SF@RP could be tuned. Tumor spheroids can be formed on SF@RP scaffolds with a dominant random secondary structure, in contrast to cells adhering and spreading on SF@RP scaffolds with a higher ratio of β-sheet secondary structures. Direct culturing of breast cancer MDA-MB-231 and MCF-7, lung cancer A549, prostate cancer DU145, and liver cancer HepG2 cells could spontaneously lead to corresponding tumor spheroids on SF@RP. In addition, the physiological characteristics of HepG2 tumor spheroids were investigated, and the results showed that compared with HepG2 monolayer cells, CYP3A4, CYP1A1, and albumin gene expression levels in HepG2 cell spheres formed on SF@RP scaffolds were significantly higher. Moreover, these spheroids showed higher drug resistance. In summary, these SF@RP scaffolds prepared by the dip-coating method are biocompatible substrates for cell culture, especially for tumor cell spheroid formation.
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Affiliation(s)
- Jingjing Fu
- Institute for Clean Energy & Advanced Materials, School of Materials & Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China
| | - Xiao Bai Li
- Institute for Clean Energy & Advanced Materials, School of Materials & Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China
| | - Lin Xiang Wang
- Institute for Clean Energy & Advanced Materials, School of Materials & Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China
| | - Xiao Hui Lv
- Institute for Clean Energy & Advanced Materials, School of Materials & Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China
| | - Zhisong Lu
- Institute for Clean Energy & Advanced Materials, School of Materials & Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China
| | - Feng Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China.,Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China.,Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China
| | - Ling Yu
- Institute for Clean Energy & Advanced Materials, School of Materials & Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China
| | - Chang Ming Li
- Institute for Clean Energy & Advanced Materials, School of Materials & Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China.,Institute of Advanced Cross-field Science, Qingdao University, Qingdao 266071, P. R. China
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6
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Roberge CL, Kingsley DM, Faulkner DE, Sloat CJ, Wang L, Barroso M, Intes X, Corr DT. Non-Destructive Tumor Aggregate Morphology and Viability Quantification at Cellular Resolution, During Development and in Response to Drug. Acta Biomater 2020; 117:322-334. [PMID: 33007490 DOI: 10.1016/j.actbio.2020.09.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/15/2020] [Accepted: 09/22/2020] [Indexed: 12/15/2022]
Abstract
Three-dimensional (3D) tissue-engineered in vitro models, particularly multicellular spheroids and organoids, have become important tools to explore disease progression and guide the development of novel therapeutic strategies. These avascular constructs are particularly powerful in oncological research due to their ability to mimic several key aspects of in vivo tumors, such as 3D structure and pathophysiologic gradients. Advancement of spheroid models requires characterization of critical features (i.e., size, shape, cellular density, and viability) during model development, and in response to treatment. However, evaluation of these characteristics longitudinally, quantitatively and non-invasively remains a challenge. Herein, Optical Coherence Tomography (OCT) is used as a label-free tool to assess 3D morphologies and cellular densities of tumor spheroids generated via the liquid overlay technique. We utilize this quantitative tool to assess Matrigel's influence on spheroid morphologic development, finding that the absence of Matrigel produces flattened, disk-like aggregates rather than 3D spheroids with physiologically-relevant features. Furthermore, this technology is adapted to quantify cell number within tumor spheroids, and to discern between live and dead cells, to non-destructively provide valuable information on tissue/construct viability, as well as a proof-of-concept for longitudinal drug efficacy studies. Together, these findings demonstrate OCT as a promising noninvasive, quantitative, label-free, longitudinal and cell-based method that can assess development and drug response in 3D cellular aggregates at a mesoscopic scale.
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Affiliation(s)
- Cassandra L Roberge
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180, USA.
| | - David M Kingsley
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180, USA.
| | - Denzel E Faulkner
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180, USA.
| | - Charles J Sloat
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180, USA.
| | - Ling Wang
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, 12208, USA.
| | - Margarida Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, 12208, USA.
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180, USA.
| | - David T Corr
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180, USA.
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Fan Z, Chen C, Pang X, Yu Z, Qi Y, Chen X, Liang H, Fang X, Sha X. Adding vitamin E-TPGS to the formulation of Genexol-PM: specially mixed micelles improve drug-loading ability and cytotoxicity against multidrug-resistant tumors significantly. PLoS One 2015; 10:e0120129. [PMID: 25831130 PMCID: PMC4382049 DOI: 10.1371/journal.pone.0120129] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 02/04/2015] [Indexed: 11/17/2022] Open
Abstract
Genexol-PM, produced by Samyang Company (Korea) is an excellent preparation of paclitaxel (PTX) for clinical cancer treatment. However, it cannot resolve the issue of multidrug resistance (MDR)—a significant problem in the administration of PTX to cancer patients. To increase the efficacy of Genexol-PM against MDR tumors, a mixed micelle capable of serving as a vehicle for PTX was developed, and two substances were chosen as carrier materials: 1) Polyethylene glycol–polylactic acid (PEG-PLA), the original vehicle of Genexol-PM. 2) Vitamin E-TPGS, an inhibitor of P-glycoprotein (P-gp). P-gp has been proven to be the main cause of MDR. In vitro evaluation indicated that the mixed micelle was an ideal PTX delivery system for the treatment of MDR tumors; the mixed micelle also showed a significantly better drug-loading coefficient than Genexol-PM.
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Affiliation(s)
- Zhuoyang Fan
- Key Laboratory of Smart Drug Delivery (Fudan University), Ministry of Education & PLA, Department of Pharmaceutics, School of Pharmacy, Fudan University, Lane 826, Zhangheng Road, Shanghai 201203, China
| | - Cheng Chen
- Key Laboratory of Smart Drug Delivery (Fudan University), Ministry of Education & PLA, Department of Pharmaceutics, School of Pharmacy, Fudan University, Lane 826, Zhangheng Road, Shanghai 201203, China
| | - Xiaoying Pang
- Key Laboratory of Smart Drug Delivery (Fudan University), Ministry of Education & PLA, Department of Pharmaceutics, School of Pharmacy, Fudan University, Lane 826, Zhangheng Road, Shanghai 201203, China
| | - Zhou Yu
- Key Laboratory of Smart Drug Delivery (Fudan University), Ministry of Education & PLA, Department of Pharmaceutics, School of Pharmacy, Fudan University, Lane 826, Zhangheng Road, Shanghai 201203, China
| | - Yang Qi
- Key Laboratory of Smart Drug Delivery (Fudan University), Ministry of Education & PLA, Department of Pharmaceutics, School of Pharmacy, Fudan University, Lane 826, Zhangheng Road, Shanghai 201203, China
| | - Xinyi Chen
- Key Laboratory of Smart Drug Delivery (Fudan University), Ministry of Education & PLA, Department of Pharmaceutics, School of Pharmacy, Fudan University, Lane 826, Zhangheng Road, Shanghai 201203, China
| | - Huihui Liang
- Key Laboratory of Smart Drug Delivery (Fudan University), Ministry of Education & PLA, Department of Pharmaceutics, School of Pharmacy, Fudan University, Lane 826, Zhangheng Road, Shanghai 201203, China
| | - Xiaoling Fang
- Key Laboratory of Smart Drug Delivery (Fudan University), Ministry of Education & PLA, Department of Pharmaceutics, School of Pharmacy, Fudan University, Lane 826, Zhangheng Road, Shanghai 201203, China
| | - Xianyi Sha
- Key Laboratory of Smart Drug Delivery (Fudan University), Ministry of Education & PLA, Department of Pharmaceutics, School of Pharmacy, Fudan University, Lane 826, Zhangheng Road, Shanghai 201203, China
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Larson AR, Lee CW, Lezcano C, Zhan Q, Huang J, Fischer AH, Murphy GF. Melanoma spheroid formation involves laminin-associated vasculogenic mimicry. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:71-8. [PMID: 24332013 DOI: 10.1016/j.ajpath.2013.09.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 08/30/2013] [Accepted: 09/18/2013] [Indexed: 10/25/2022]
Abstract
Melanoma is a tumor where virulence is conferred on transition from flat (radial) to three-dimensional (tumorigenic) growth. Virulence of tumorigenic growth is governed by numerous attributes, including presence of self-renewing stem-like cells and related formation of patterned networks associated with the melanoma mitogen, laminin, a phenomenon known as vasculogenic mimicry. Vasculogenic mimicry is posited to contribute to melanoma perfusion and nutrition in vivo; we hypothesized that it may also play a role in stem cell-driven spheroid formation in vitro. Using a model of melanoma in vitro tumorigenesis, laminin-associated networks developed in association with three-dimensional melanoma spheroids. Real-time PCR analysis of laminin subunits showed that spheroids formed from anchorage-independent melanoma cells expressed increased α4 and β1 laminin chains and α4 laminin expression was confirmed by in situ hybridization. Association of laminin networks with melanoma stem cell-associated nestin and vascular endothelial growth factor receptor-1 also was documented. Moreover, knockdown of nestin gene expression impaired laminin expression and network formation within spheroids. Laminin networks were remarkably similar to those observed in melanoma xenografts in mice and to those seen in patient melanomas. These data indicate that vasculogenic mimicry-like laminin networks, in addition to their genesis in vivo, are integral to the extracellular architecture of melanoma spheroids in vitro, where they may serve as stimulatory scaffolds to support three-dimensional growth.
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Affiliation(s)
- Allison R Larson
- Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts
| | - Chung-Wei Lee
- Division of Dermatopathology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts
| | - Cecilia Lezcano
- Division of Dermatopathology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts
| | - Qian Zhan
- Division of Dermatopathology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts
| | - John Huang
- Division of Dermatopathology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts
| | - Andrew H Fischer
- Department of Pathology, University of Massachusetts Medical Center, Worcester, Massachusetts
| | - George F Murphy
- Division of Dermatopathology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts.
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Arsenault DJ, Yoo BH, Rosen KV, Ridgway ND. ras-Induced up-regulation of CTP:phosphocholine cytidylyltransferase α contributes to malignant transformation of intestinal epithelial cells. J Biol Chem 2012; 288:633-43. [PMID: 23155050 DOI: 10.1074/jbc.m112.347682] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cancer cells have enhanced lipogenic capacity characterized by increased synthesis of fatty acids and complex lipids, including phosphatidylcholine (PC). As the rate-limiting enzyme in the CDP-choline pathway for PC synthesis, CTP:phosphocholine cytidylyltransferase α (CCTα) is implicated in the provision of membranes and bioactive lipids necessary of cell proliferation. In this study, we assessed the role of CCTα in malignant intestinal epithelial cells transformed with activated H-ras (IEC-ras). Three IEC-ras clones had significant up-regulation CCTα expression, but PC synthesis and in vitro activity of CCTα were similar to control IEC. RNA interference of CCTα in adherent IEC-ras did not affect PC synthesis, confirming that the enzyme was relatively inactive. However, CCTα silencing in ras-transformed IEC reduced anchorage-independent growth, a criterion for malignant transformation, as well as tumorigenicity in mice. Relative to their adherent counterparts, detached IEC-ras had increased PC synthesis that was attenuated by inducible CCTα silencing. Detachment of IEC-ras was accompanied by increased CCTα phosphorylation and cytosolic enzyme activity. We conclude that the expanded pool of CCTα in IEC-ras is activated by detachment. This provides the increased PC biosynthetic capacity that contributes to malignant transformation of intestinal epithelial cells when detached from the extracellular matrix.
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Affiliation(s)
- Daniel J Arsenault
- Atlantic Research Centre, Department of Pediatrics and Biochemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
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10
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Gaustad JV, Simonsen TG, Leinaas MN, Rofstad EK. Sunitinib treatment does not improve blood supply but induces hypoxia in human melanoma xenografts. BMC Cancer 2012; 12:388. [PMID: 22947392 PMCID: PMC3489843 DOI: 10.1186/1471-2407-12-388] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 08/31/2012] [Indexed: 11/18/2022] Open
Abstract
Background Antiangiogenic agents that disrupt the vascular endothelial growth factor pathway have been demonstrated to normalize tumor vasculature and improve tumor oxygenation in some studies and to induce hypoxia in others. The aim of this preclinical study was to investigate the effect of sunitinib treatment on the morphology and function of tumor vasculature and on tumor oxygenation. Methods A-07-GFP and R-18-GFP human melanoma xenografts grown in dorsal window chambers were used as preclinical tumor models. Morphologic parameters of tumor vascular networks were assessed from high-resolution transillumination images, and tumor blood supply time was assessed from first-pass imaging movies recorded after a bolus of 155 kDa tetramethylrhodamine isothiocyanate-labeled dextran had been administered intravenously. Tumor hypoxia was assessed from immunohistochemical preparations of the imaged tissue by use of pimonidazole as a hypoxia marker. Results Sunitinib treatment reduced vessel densities, increased vessel segment lengths, did not affect blood supply times, and increased hypoxic area fractions. Conclusion Sunitinib treatment did not improve vascular function but induced hypoxia in A-07-GFP and R-18-GFP tumors.
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Affiliation(s)
- Jon-Vidar Gaustad
- Group of Radiation Biology and Tumor Physiology, Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Norway.
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11
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Simonsen TG, Gaustad JV, Leinaas MN, Rofstad EK. High interstitial fluid pressure is associated with tumor-line specific vascular abnormalities in human melanoma xenografts. PLoS One 2012; 7:e40006. [PMID: 22768196 PMCID: PMC3386940 DOI: 10.1371/journal.pone.0040006] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 05/30/2012] [Indexed: 12/22/2022] Open
Abstract
Purpose Interstitial fluid pressure (IFP) is highly elevated in many solid tumors. High IFP has been associated with low radiocurability and high metastatic frequency in human melanoma xenografts and with poor survival after radiation therapy in cervical cancer patients. Abnormalities in tumor vascular networks have been identified as an important cause of elevated tumor IFP. The aim of this study was to investigate the relationship between tumor IFP and the functional and morphological properties of tumor vascular networks. Materials and Methods A-07-GFP and R-18-GFP human melanomas growing in dorsal window chambers in BALB/c nu/nu mice were used as preclinical tumor models. Functional and morphological parameters of the vascular network were assessed from first-pass imaging movies and vascular maps recorded after intravenous bolus injection of 155-kDa tetramethylrhodamine isothiocyanate-labeled dextran. IFP was measured in the center of the tumors using a Millar catheter. Angiogenic profiles of A-07-GFP and R-18-GFP cells were obtained with a quantitative PCR array. Results High IFP was associated with low growth rate and low vascular density in A-07-GFP tumors, and with high growth rate and high vascular density in R-18-GFP tumors. A-07-GFP tumors showed chaotic and highly disorganized vascular networks, while R-18-GFP tumors showed more organized vascular networks with supplying arterioles in the tumor center and draining venules in the tumor periphery. Furthermore, A-07-GFP and R-18-GFP cells differed substantially in angiogenic profiles. A-07-GFP tumors with high IFP showed high geometric resistance to blood flow due to high vessel tortuosity. R-18-GFP tumors with high IFP showed high geometric resistance to blood flow due to a large number of narrow tumor capillaries. Conclusions High IFP in A-07-GFP and R-18-GFP human melanoma xenografts was primarily a consequence of high blood flow resistance caused by tumor-line specific vascular abnormalities.
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Affiliation(s)
- Trude G Simonsen
- Group of Radiation Biology and Tumor Physiology, Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.
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12
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Blood supply in melanoma xenografts is governed by the morphology of the supplying arteries. Neoplasia 2009; 11:277-85. [PMID: 19242609 DOI: 10.1593/neo.81400] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 12/04/2008] [Accepted: 12/04/2008] [Indexed: 12/27/2022] Open
Abstract
Tumor blood supply was related to the morphology of the tumor microvasculature and the supplying arteries (SAs) of A-07-GFP and D-12-GFP melanoma xenografts growing in window chamber preparations in BALB/c nu/nu mice. Blood supply and morphologic parameters were determined from first-pass imaging movies and vascular maps recorded after a bolus of 155-kDa tetramethylrhodamine isothiocyanate-labeled dextran had been administered intravenously. Poorly supplied tumors showed microvascular networks that did not differ from those of well-supplied tumors in vessel tortuosity, diameter, and density. Conversely, the SAs of poorly supplied tumors were more tortuous and had a smaller diameter than those of well-supplied tumors, resulting in lower plasma velocities in the downstream tumor vessels. Consequently, the blood supply of A-07-GFP and D-12-GFP tumors was governed by the geometric resistance of the SAs rather than by the geometric resistance or the vessel density of the tumor microvasculature. The present study suggests that the SAs may represent an important target for physiological interventions of tumors and that it may be beneficial to focus on the tumor SAs rather than the tumor microvasculature when searching for novel therapeutic strategies for modifying tumor blood supply.
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Gulliksrud K, Vestvik IK, Galappathi K, Mathiesen B, Rofstad EK. Detection of different hypoxic cell subpopulations in human melanoma xenografts by pimonidazole immunohistochemistry. Radiat Res 2008; 170:638-50. [PMID: 18959463 DOI: 10.1667/rr1400.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Accepted: 07/18/2008] [Indexed: 11/03/2022]
Abstract
This study aimed at developing immunohistochemical assays for different subpopulations of hypoxic cells in tumors. BALB/c-nu/nu mice bearing A-07 or R-18 tumors were given a single dose of 90 mg/kg body weight or three doses (3 h apart) of 30 mg/kg body weight of pimonidazole hydrochloride intravenously. The fraction of pimonidazole-labeled cells was assessed in paraffin-embedded and frozen tumor sections and compared with the fraction of radiobiologically hypoxic cells. The staining pattern in paraffin-embedded sections indicated selective staining of chronically hypoxic cells. Frozen sections showed a staining pattern consistent with staining of both chronically and acutely/repetitively hypoxic cells. Fraction of pimonidazole-labeled cells in paraffin-embedded sections was lower than the fraction of radiobiologically hypoxic cells (single-dose and triple-dose experiment). In frozen sections, fraction of pimonidazole-labeled cells was similar to (single-dose experiment) or higher than (triple-dose experiment) fraction of radiobiologically hypoxic cells. Three different subpopulations of hypoxic cells could be quantified by pimonidazole immunohistochemistry: the fraction of cells that are hypoxic because of limitations in oxygen diffusion, the fraction of cells that are hypoxic simultaneously because of fluctuations in blood perfusion, and the fraction of cells that are exposed to one or more periods of hypoxia during their lifetime because of fluctuations in blood perfusion.
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Affiliation(s)
- Kristine Gulliksrud
- Group of Radiation Biology and Tumor Physiology, Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Montebello, Oslo, Norway
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Tumor vascularity assessed by magnetic resonance imaging and intravital microscopy imaging. Neoplasia 2008; 10:354-62. [PMID: 18392132 DOI: 10.1593/neo.08162] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 02/06/2008] [Accepted: 02/06/2008] [Indexed: 11/18/2022] Open
Abstract
Gadopentetate dimeglumine (Gd-DTPA)-based dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is considered to be a useful method for characterizing the vascularity of tumors. However, detailed studies of experimental tumors comparing DCE-MRI-derived parametric images with images of the morphology and function of the microvascular network have not been reported. In this communication, we describe a novel MR-compatible mouse dorsal window chamber and report comparative DCE-MRI and intravital microscopy studies of A-07-GFP tumors xenografted to BALB/c nu/nu mice. Blood supply time (BST) images (i.e., images of the time from when arterial blood enters a tumor through the supplying artery until it reaches a vessel segment within the tumor) and morphologic images of the microvascular network were produced by intravital microscopy. Images of E.F (E is the initial extraction fraction of Gd-DTPA and F is perfusion) were produced by subjecting DCE-MRI series to Kety analysis. The E.F images mirrored the morphology (microvascular density) and the function (BST) of the microvascular networks well. Tumor regions showing high E.F values colocalized with tumor regions showing high microvascular density and low BST values. Significant correlations were found between E.F and microvascular density and between E.F and BST, both within and among tumors.
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Shiras A, Bhosale A, Patekar A, Shepal V, Shastry P. Differential expression of CD44(S) and variant isoforms v3, v10 in three-dimensional cultures of mouse melanoma cell lines. Clin Exp Metastasis 2002; 19:445-55. [PMID: 12198773 DOI: 10.1023/a:1016305611858] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Multi-cellular spheroids (MCS) generated from tumor cells serve as excellent in vitro models for understanding the mechanisms of tumor progression and micro-metastasis. We have compared the expression of molecular markers with reference to their growth as conventional adherent monolayers (2-D) and anchorage independent cultures (3-D) using two mouse melanoma cell lines, B16F10 and Clone M3. The two cell lines differed in their ability to form spheroids with respect to their aggregation potential, with B16F10 forming large clusters compared to Clone M3. A panel of molecular markers comprising cell adhesion molecules, cyclin dependent kinase inhibitors and members of the cadherin-catenin complex were analyzed by flow cytometry in 2-D and 3-D cultures. There was a distinct difference in the patterns of expression of CD44(S) and variant isoforms v3, v10 in spheroids compared to cells grown as monolayers in both cell lines. Also, there was an increase in cells positive for CDK inhibitor p27 in 3-D cultures from the B16F10 cell line. The expression of alpha and gamma catenin was down regulated in spheroids. As these molecules are implicated in the regulation of cell proliferation, alterations in the expression of these molecules in 3-D cultures compared to their 2-D counterparts suggests the importance of spheroids as experimental model for tumorigenesis.
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Affiliation(s)
- Anjali Shiras
- National Centre for Cell Science (NCCS), NCCS Complex, Ganeshkhind, Pune 411007, India.
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16
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Rak J, Mitsuhashi Y, Erdos V, Huang SN, Filmus J, Kerbel RS. Massive programmed cell death in intestinal epithelial cells induced by three-dimensional growth conditions: suppression by mutant c-H-ras oncogene expression. J Cell Biol 1995; 131:1587-98. [PMID: 8522614 PMCID: PMC2120690 DOI: 10.1083/jcb.131.6.1587] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Deregulation of molecular pathways controlling cell survival and death, including programmed cell death, are thought to be important factors in tumor formation, disease progression, and response to therapy. Studies devoted to analyzing the role of programmed cell death in cancer have been carried out primarily using conventional monolayer cell culture systems. However the majority of cancers grow as three-dimensional solid tumors. Because gene expression, and possibly function, can be significantly altered under such conditions, we decided to analyze the control and characteristics of cell death using a compatible three-dimensional tissue culture system (multicellular spheroids) and compare the results obtained to those using two-dimensional monolayer cell culture. To do so we selected for study an immortalized, but nontumorigenic line of rat intestinal epithelial cells, called IEC-18, and several tumorigenic variants of IEC-18 obtained by transfection with a mutant (activated) c-H-ras oncogene. The rationale for choosing these cell lines was based in part on the fact that intestinal epithelial cells grow in vivo in a monolayer-like manner and form solid tumors only after sustaining certain genetic mutations, including those involving the ras gene family. We found that the IEC-18 cells, which grow readily and survive in monolayer cell culture, undergo massive cell death within 48-72 h when cultured as multicellular spheroids on a nonadhesive surface. This process was accompanied by a number of features associated with programmed cell death including chromatin condensation (Hoechst 33258 staining) apoptotic morphology, DNA degradation, and a virtual complete loss of colony forming (clonogenic) ability in the absence of apparent membrane damage as well as accumulation of lipid containing vacuoles in the cytoplasm. Moreover, enforced over-expression of a transfected bcl-2 gene could prevent this cell death process from taking place. In marked contrast, three different stably transfected ras clones of IEC-18 survived when grown as multicellular spheroids. In addition, an IEC cell line (called clone 25) carrying its mutant transfected ras under a glucocorticoid inducible promoter survived in three-dimensional culture only when the cells were exposed to dexamethasone. If exposure to dexamethasone was delayed for as long as 48 h the cells nevertheless survived, whereas the cells became irreversibly committed to programmed cell death (PCD) if exposed to dexamethasone after 72 h. These results suggest that intestinal epithelial cells may be programmed to activate a PCD pathway upon detachment from a physiologic two-dimensional monolayer configuration, and that this process of adhesion regulated programmed cell death (ARPCD) can be substantially suppressed by expression of a mutant ras oncogene.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- J Rak
- Division of Cancer Biology Research, Reichmann Research Building, Sunnybrook Health Science Centre, Toronto, Ontario
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Rak JW, Kerbel RS. Growth advantage ("clonal dominance") of metastatically competent tumor cell variants expressed under selective two- or three-dimensional tissue culture conditions. In Vitro Cell Dev Biol Anim 1993; 29A:742-8. [PMID: 8407718 DOI: 10.1007/bf02631431] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In previous experiments it was shown that injection into syngeneic CBA/J mice of cell mixtures containing an excess of non-metastatic SP1 mouse mammary carcinoma cells with a ras transfected metastatic variant of SP1 called C1, always resulted in the eventual dominance of the C1 subpopulation at the site of inoculation. This occurred despite the growth rates of the two cell populations being identical in vivo when grown separately. The means by which the C1 subpopulation achieved "clonal dominance" is thought to involve its responsiveness to stimulatory paracrine growth factors liberated by the non-metastatic SP1 population. The clonal dominance process, however, could not be recapitulated in conventional monolayer tissue culture conditions in which SP1 and C1 cells were grown together in high concentrations of serum, i.e. under non-limiting culture conditions. We now show that clonal dominance of C1 cells can be observed when the cell mixture is maintained in tissue culture for extended periods, or when the cells are grown under selective, limiting conditions, some of which may mimic growth conditions in vivo more accurately. These conditions were a) growth in low (limiting) serum concentrations; and b) growth as three-dimensional multicellular aggregates, i.e. as "tumor spheroids". Under all of these conditions dominance of the C1 subpopulation always took place, but with an efficiency 6- to 40-fold less than generally observed in vivo. C1 cells were also able to form more stable (compact) spheroids compared to SP1 cells. Entrapment of the latter in mixed C1/SP1 spheroids increased the recovery of the SP1 cells suggesting some kind of "rescue" mechanism in which cells are protected from physical forces by three-dimensional structure. The relevance of these in vitro interactions for clonal dominance in primary tumors and metastasis in vivo are discussed.
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Affiliation(s)
- J W Rak
- Division of Cancer Research, Sunnybrook Health Science Centre, Toronto, Canada
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Kobayashi H, Man S, Graham CH, Kapitain SJ, Teicher BA, Kerbel RS. Acquired multicellular-mediated resistance to alkylating agents in cancer. Proc Natl Acad Sci U S A 1993; 90:3294-8. [PMID: 8475071 PMCID: PMC46286 DOI: 10.1073/pnas.90.8.3294] [Citation(s) in RCA: 195] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
EMT-6 murine mammary tumor sublines highly resistant to cyclophosphamide, cis-diamminedichloro-platinum(II), or N,N',N"-triethylenethiophosphoramide were generated in vivo by sequential treatment of tumor-bearing mice with the respective drugs. Previous studies demonstrated the drug-resistant phenotypes of the sublines were not expressed in vitro when the cells were grown as monolayer cultures. We now show that expression of drug resistance--including patterns of cross-drug resistance observed in vivo--can be fully recapitulated in vitro when the cells are grown under in vivo-like, three-dimensional conditions--namely, as multicellular tumor spheroids. Moreover, the spheroids generated from all of the drug-resistant sublines manifested a much more compact structure. Immediate drug-sensitivity testing of single cells released by trypsin treatment from compact drug-resistant spheroids revealed that such cells lost much of their drug-resistant properties. The results suggest a possible mechanism of acquired drug resistance in tumors based on the response of a cell population (i.e., multicellular or tissue resistance) as opposed to classic (uni)cellular resistance mechanisms.
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Affiliation(s)
- H Kobayashi
- Division of Cancer Research, Sunnybrook Health Science Centre, Toronto, ON, Canada
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Rofstad EK, Sutherland RM. Growth and radiation sensitivity of the MLS human ovarian carcinoma cell line grown as multicellular spheroids and xenografted tumours. Br J Cancer 1989; 59:28-35. [PMID: 2757922 PMCID: PMC2246982 DOI: 10.1038/bjc.1989.7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The growth characteristics and the radiation sensitivity of multicellular spheroids of the MLS human ovarian carcinoma cell line grown in spinner culture in atmospheres of 5% CO2 in air or 5% CO2, 5% O2 and 90% N2 were studied and compared to that of MLS xenografted tumours. The spheroids grew exponentially with a volume-doubling time of approximately 24 h up to a diameter of approximately 580 microns and then the growth rate tapered off, more for spheroids grown at the low than at the high oxygen tension. Thirty days after initiation, the spheroid diameters were approximately 1,500 microns at the low and 2,100 microns at the high oxygen tension. The tumour volume-doubling times were approximately 8 days (V less than 200 mm3) and 17 days (V = 1,000-4,000 mm3). The histological appearance of the spheroids and the tumours was remarkably similar; both developed large central necrosis and both were composed of epithelial cells and showed pseudoglandular structures with lumen. The spheroids were slightly less differentiated than the tumours. The intrinsic, cellular radiation sensitivity was independent of whether the cells were grown in vitro as spheroids or in vivo as tumours, as revealed by irradiating single cells from dissociated spheroids and tumours under aerobic conditions and intact spheroids and tumours under hypoxic conditions. Studies of 1,600 microns spheroids grown in 5% CO2 in air showed that the intrinsic radiation sensitivity of the chronically hypoxic cells was the same as that of acutely hypoxic cells. The fraction of radiobiologically hypoxic cells under these conditions was approximately 15% and similar to those of 9% (V = 200 mm3) and 28% (V = 2,000 mm3) found for the tumours. Spheroids with diameter of 1,200 microns did not show survival curves parallel to those for acutely hypoxic cells, i.e. they did not contain a measurable fraction of clonogenic cells at complete radiobiological hypoxia. The final portion of their survival curves represented partially hypoxic cells; the OERs were 1.6 and 1.3 for spheroids grown at the high and the low oxygen tension, respectively. The considerable similarity between the spheroids and the tumours suggests that MLS spheroids constitute a valuable in vitro model for studies of human tumour radiation biology and related physiological processes. MLS spheroids may be particularly useful in studies of therapeutic consequences of partial radiobiological hypoxia since complete hypoxia and different levels of partial hypoxia can be studied separately by varying spheroid size and the oxygen tension in the culture medium.
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Affiliation(s)
- E K Rofstad
- Experimental Therapeutics Division, University of Rochester Cancer Center, New York
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Rofstad EK. Growth and radiosensitivity of malignant melanoma multicellular spheroids initiated directly from surgical specimens of tumours in man. Br J Cancer 1986; 54:569-78. [PMID: 3778801 PMCID: PMC2001490 DOI: 10.1038/bjc.1986.211] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The growth and radiosensitivity of multicellular spheroids initiated directly from disaggregated surgical specimens of four human malignant melanomas were studied. The spheroids were grown in liquid-overlay culture for up to 6 passages. Cell survival following irradiation was measured by using the Courtenay soft agar colony assay. The four melanomas formed spherical, densely packed spheroids. The volumetric growth rate as well as the plating efficiency in soft agar usually increased with increasing passage number. The radiosensitivity differed significantly among the melanomas. The survival curves for single cells from disaggregated spheroids in the first passage were always similar to those for single cells isolated directly from the surgical specimens. Two of the melanomas showed a significant contact effect as spheroids whereas the other two did not. The spheroids of two of the melanomas showed lower D0 in the third and the sixth passage than in the first passage, whereas the spheroids of the other two melanomas showed similar survival curves in the first and the third passage. There was no clear relationship between the changes in radiosensitivity and the changes in growth rate or plating efficiency. It is concluded that spheroids in the first passage, but not spheroids in later passages, may have the potential to identify differences in clinical radioresponsiveness among tumours.
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