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Maslivetc VA, Nabiul Hasan M, Boari A, Zejnelovski A, Evidente A, Sun D, Kornienko A. Ophiobolin A derivatives with enhanced activities under tumor-relevant acidic conditions. Bioorg Med Chem Lett 2024; 110:129863. [PMID: 38942129 DOI: 10.1016/j.bmcl.2024.129863] [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: 04/18/2024] [Revised: 06/20/2024] [Accepted: 06/25/2024] [Indexed: 06/30/2024]
Abstract
Glioblastoma (GBM) is the most common form of malignant primary brain tumor and is one of the most lethal cancers. The difficulty in treating GBM stems from its highly developed mechanisms of drug resistance. Our research team has recently identified the fungal secondary metabolite ophiobolin A (OpA) as an agent with significant activity against drug-resistant GBM cells. However, the OpA's mode of action is likely based on covalent modification of its intracellular target(s) and thus possible off-target reactivity needs to be addressed. This work involves the investigation of an acid-sensitive OpA analogue approach that exploits the elevated acidity of the GBM microenvironment to enhance the selectivity for tumor targeting. This project identified analogues that showed selectivity at killing GBM cells grown in cultures at reduced pH compared to those maintained under normal neutral conditions. These studies are expected to facilitate the development of OpA as an anti-GBM agent by investigating its potential use in an acid-sensitive analogue form with enhanced selectivity for tumor targeting.
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Affiliation(s)
- Vladimir A Maslivetc
- Department of Chemistry and Biochemistry, Texas State University, 601 University Dr., San Marcos, TX 78666, USA
| | - Md Nabiul Hasan
- Department of Neurology, University of Pittsburgh, 3501 Fifth Ave, Pittsburgh, PA 15260, USA
| | - Angela Boari
- Institute of Sciences of Food Production, National Research Council, Via Amendola 122/O, 70125 Bari, Italy
| | - Arben Zejnelovski
- Department of Chemistry and Biochemistry, Texas State University, 601 University Dr., San Marcos, TX 78666, USA
| | - Antonio Evidente
- Institute of Biomolecular Chemistry, National Research Council, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, 3501 Fifth Ave, Pittsburgh, PA 15260, USA; Research Service, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA, USA
| | - Alexander Kornienko
- Department of Chemistry and Biochemistry, Texas State University, 601 University Dr., San Marcos, TX 78666, USA.
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2
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Tafech A, Stéphanou A. On the Importance of Acidity in Cancer Cells and Therapy. BIOLOGY 2024; 13:225. [PMID: 38666837 PMCID: PMC11048434 DOI: 10.3390/biology13040225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024]
Abstract
Cancer cells are associated with high glycolytic activity, which results in acidification of the tumor microenvironment. The occurrence of this stressful condition fosters tumor aggressiveness, with the outcome of invasiveness and metastasis that are linked to a poor clinical prognosis. Acidosis can be both the cause or consequence of alterations in the functions and expressions of transporters involved in intracellular acidity regulation. This review aims to explore the origin of acidity in cancer cells and the various mechanisms existing in tumors to resist, survive, or thrive in the acidic environment. It highlights the difficulties in measuring the intracellular pH evolution that impedes our understanding of the many regulatory and feedback mechanisms. It finally presents the consequences of acidity on tumor development as well as the friend or foe role of acidity in therapy.
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Affiliation(s)
| | - Angélique Stéphanou
- Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
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3
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Randhawa K, Jahani-Asl A. CLIC1 regulation of cancer stem cells in glioblastoma. CURRENT TOPICS IN MEMBRANES 2023; 92:99-123. [PMID: 38007271 DOI: 10.1016/bs.ctm.2023.09.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2023]
Abstract
Chloride intracellular channel 1 (CLIC1) has emerged as a therapeutic target in various cancers. CLIC1 promotes cell cycle progression and cancer stem cell (CSC) self-renewal. Furthermore, CLIC1 is shown to play diverse roles in proliferation, cell volume regulation, tumour invasion, migration, and angiogenesis. In glioblastoma (GB), CLIC1 facilitates the G1/S phase transition and tightly regulates glioma stem-like cells (GSCs), a rare population of self-renewing CSCs with central roles in tumour resistance to therapy and tumour recurrence. CLIC1 is found as either a monomeric soluble protein or as a non-covalent dimeric protein that can form an ion channel. The ratio of dimeric to monomeric protein is altered in GSCs and depends on the cell redox state. Elucidating the mechanisms underlying the alterations in CLIC1 expression and structural transitions will further our understanding of its role in GSC biology. This review will highlight the role of CLIC1 in GSCs and its significance in facilitating different hallmarks of cancer.
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Affiliation(s)
- Kamaldeep Randhawa
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada; Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - Arezu Jahani-Asl
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada; Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada; Regenerative Medicine Program and Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.
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4
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Tafech A, Jacquet P, Beaujean C, Fertin A, Usson Y, Stéphanou A. Characterization of the Intracellular Acidity Regulation of Brain Tumor Cells and Consequences for Therapeutic Optimization of Temozolomide. BIOLOGY 2023; 12:1221. [PMID: 37759620 PMCID: PMC10525637 DOI: 10.3390/biology12091221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023]
Abstract
A well-known feature of tumor cells is high glycolytic activity, leading to acidification of the tumor microenvironment through extensive lactate production. This acidosis promotes processes such as metastasis, aggressiveness, and invasiveness, which have been associated with a worse clinical prognosis. Moreover, the function and expression of transporters involved in regulation of intracellular pH might be altered. In this study, the capacity of tumor cells to regulate their intracellular pH when exposed to a range of pH from very acidic to basic was characterized in two glioma cell lines (F98 and U87) using a new recently published method of fluorescence imaging. Our results show that the regulation of acidity in tumors is not the same for the two investigated cell lines; U87 cells are able to reduce their intracellular acidity, whereas F98 cells do not exhibit this property. On the other hand, F98 cells show a higher level of resistance to acidity than U87 cells. Intracellular regulation of acidity appears to be highly cell-dependent, with different mechanisms activated to preserve cell integrity and function. This characterization was performed on 2D monolayer cultures and 3D spheroids. Spatial heterogeneities were exhibited in 3D, suggesting a spatially modulated regulation in this context. Based on the corpus of knowledge available in the literature, we propose plausible mechanisms to interpret our results, together with some new lines of investigation to validate our hypotheses. Our results might have implications on therapy, since the activity of temozolomide is highly pH-dependent. We show that the drug efficiency can be enhanced, depending on the cell type, by manipulating the extracellular pH. Therefore, personalized treatment involving a combination of temozolomide and pH-regulating agents can be considered.
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Affiliation(s)
| | | | | | | | | | - Angélique Stéphanou
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France; (A.T.); (P.J.); (C.B.); (A.F.); (Y.U.)
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5
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Eatmann AI, Hamouda E, Hamouda H, Farouk HK, Jobran AWM, Omar AA, Madeeh AK, Al-Dardery NM, Elnoamany S, Abd-Elnasser EG, Koraiem AM, Ahmed AA, Abouzid M, Karaźniewicz-Łada M. Potential Use of Thalidomide in Glioblastoma Treatment: An Updated Brief Overview. Metabolites 2023; 13:metabo13040543. [PMID: 37110201 PMCID: PMC10146416 DOI: 10.3390/metabo13040543] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/05/2023] [Accepted: 04/09/2023] [Indexed: 04/29/2023] Open
Abstract
Glioblastoma is the most common malignant primary brain tumor in adults. Thalidomide is a vascular endothelial growth factor inhibitor that demonstrates antiangiogenic activity, and may provide additive or synergistic anti-tumor effects when co-administered with other antiangiogenic medications. This study is a comprehensive review that highlights the potential benefits of using thalidomide, in combination with other medications, to treat glioblastoma and its associated inflammatory conditions. Additionally, the review examines the mechanism of action of thalidomide in different types of tumors, which may be beneficial in treating glioblastoma. To our knowledge, a similar study has not been conducted. We found that thalidomide, when used in combination with other medications, has been shown to produce better outcomes in several conditions or symptoms, such as myelodysplastic syndromes, multiple myeloma, Crohn's disease, colorectal cancer, renal failure carcinoma, breast cancer, glioblastoma, and hepatocellular carcinoma. However, challenges may persist for newly diagnosed or previously treated patients, with moderate side effects being reported, particularly with the various mechanisms of action observed for thalidomide. Therefore, thalidomide, used alone, may not receive significant attention for use in treating glioblastoma in the future. Conducting further research by replicating current studies that show improved outcomes when thalidomide is combined with other medications, using larger sample sizes, different demographic groups and ethnicities, and implementing enhanced therapeutic protocol management, may benefit these patients. A meta-analysis of the combinations of thalidomide with other medications in treating glioblastoma is also needed to investigate its potential benefits further.
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Affiliation(s)
- Ahmed Ismail Eatmann
- Department of Cell Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University in Kraków, 31-007 Kraków, Poland
| | - Esraa Hamouda
- Faculty of Medicine, Menoufia University, Menoufia P.O. Box 5744, Egypt
| | - Heba Hamouda
- Faculty of Medicine, Menoufia University, Menoufia P.O. Box 5744, Egypt
| | | | - Afnan W M Jobran
- Faculty of Medicine, Al Quds University, Jerusalem P.O. Box 51000, Palestine
| | - Abdallah A Omar
- Department of Pharmaceutical Services and Sciences, Children's Cancer Hospital Egypt (CCHE-57357), Cairo 11617, Egypt
| | | | | | - Salma Elnoamany
- Faculty of Medicine, Menoufia University, Menoufia P.O. Box 5744, Egypt
| | | | | | - Alhassan Ali Ahmed
- Department of Bioinformatics and Computational Biology, Poznan University of Medical Sciences, 60-812 Poznan, Poland
- Doctoral School, Poznan University of Medical Sciences, 60-812 Poznan, Poland
| | - Mohamed Abouzid
- Doctoral School, Poznan University of Medical Sciences, 60-812 Poznan, Poland
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, Rokietnicka 3 St., 60-806 Poznan, Poland
| | - Marta Karaźniewicz-Łada
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, Rokietnicka 3 St., 60-806 Poznan, Poland
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6
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Compact Smartphone-Based Laser Speckle Contrast Imaging Endoscope Device for Point-of-Care Blood Flow Monitoring. BIOSENSORS 2022; 12:bios12060398. [PMID: 35735546 PMCID: PMC9220785 DOI: 10.3390/bios12060398] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/02/2022] [Accepted: 06/07/2022] [Indexed: 11/17/2022]
Abstract
Laser speckle contrast imaging (LSCI) is a powerful visualization tool for quantifying blood flow in tissues, providing simplicity of configuration, ease of use, and intuitive results. With recent advancements, smartphone and camera technologies are suitable for the development of smartphone-based LSCI applications for point-of-care (POC) diagnosis. A smartphone-based portable LSCI endoscope system was validated for POC diagnosis of vascular disorders. The endoscope consisted of compact LED and laser illumination, imaging optics, and a flexible fiberscope assembled in a 3D-printed hand-held cartridge for access to body cavities and organs. A smartphone’s rear camera was mounted thereto, enabling endoscopy, LSCI image acquisition, and processing. Blood flow imaging was calibrated in a perfused tissue phantom consisting of a microparticle solution pumped at known rates through tissue-mimicking gel and validated in a live rat model of BBN-induced bladder cancer. Raw LSCI images successfully visualized phantom flow: speckle flow index showed linearity with the pump flow rate. In the rat model, healthy and cancerous bladders were distinguishable in structure and vasculature. The smartphone-based low-cost portable mobile endoscope for monitoring blood flow and perfusion shows promise for preclinical applications and may be suitable for primary diagnosis at home or as a cost-effective POC testing assay.
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ElFar OA, Billa N, Lim HR, Chew KW, Cheah WY, Munawaroh HSH, Balakrishnan D, Show PL. Advances in delivery methods of Arthrospira platensis (spirulina) for enhanced therapeutic outcomes. Bioengineered 2022; 13:14681-14718. [PMID: 35946342 PMCID: PMC9373759 DOI: 10.1080/21655979.2022.2100863] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 07/08/2022] [Accepted: 07/08/2022] [Indexed: 12/02/2022] Open
Abstract
Arthrospira platensis (A. platensis) aqueous extract has massive amounts of natural products that can be used as future drugs, such as C-phycocyanin, allophycocyanin, etc. This extract was chosen because of its high adaptability, which reflects its resolute genetic composition. The proactive roles of cyanobacteria, particularly in the medical field, have been discussed in this review, including the history, previous food and drug administration (FDA) reports, health benefits and the various dose-dependent therapeutic functions that A. platensis possesses, including its role in fighting against lethal diseases such as cancer, SARS-CoV-2/COVID-19, etc. However, the remedy will not present its maximal effect without the proper delivery to the targeted place for deposition. The goal of this research is to maximize the bioavailability and delivery efficiency of A. platensis constituents through selected sites for effective therapeutic outcomes. The solutions reviewed are mainly on parenteral and tablet formulations. Moreover, suggested enteric polymers were discussed with minor composition variations applied for better storage in high humid countries alongside minor variations in the polymer design were suggested to enhance the premature release hindrance of basic drugs in low pH environments. In addition, it will open doors for research in delivering active pharmaceutical ingredients (APIs) in femtoscale with the use of various existing and new formulations.Abbrevations: SDGs; Sustainable Development Goals, IL-4; Interleukin-4, HDL; High-Density Lipoprotein, LDL; Low-Density Lipoprotein, VLDL; Very Low-Density Lipoprotein, C-PC; C-Phycocyanin, APC; Allophycocyanin, PE; Phycoerythrin, COX-2; Cyclooxygenase-2, RCTs; Randomized Control Trials, TNF-α; Tumour Necrosis Factor-alpha, γ-LFA; Gamma-Linolenic Fatty Acid, PGs; Polyglycans, PUFAs: Polyunsaturated Fatty Acids, NK-cell; Natural Killer Cell, FDA; Food and Drug Administration, GRAS; Generally Recognized as Safe, SD; Standard Deviation, API; Active Pharmaceutical Ingredient, DW; Dry Weight, IM; Intramuscular, IV; Intravenous, ID; Intradermal, SC; Subcutaneous, AERs; Adverse Event Reports, DSI-EC; Dietary Supplement Information Executive Committee, cGMP; Current Good Manufacturing Process, A. platensis; Arthrospira platensis, A. maxima; Arthrospira maxima, Spirulina sp.; Spirulina species, Arthrospira; Spirulina, Tecuitlatl; Spirulina, CRC; Colorectal Cancer, HDI; Human Development Index, Tf; Transferrin, TfR; Transferrin Receptor, FR; Flow Rate, CPP; Cell Penetrating Peptide, SUV; Small Unilamenar Vesicle, LUV; Large Unilamenar Vesicle, GUV; Giant Unilamenar Vesicle, MLV; Multilamenar Vesicle, COVID-19; Coronavirus-19, PEGylated; Stealth, PEG; Polyethylene Glycol, OSCEs; Objective Structured Clinical Examinations, GI; Gastrointestinal Tract, CAP; Cellulose Acetate Phthalate, HPMCP, Hydroxypropyl Methyl-Cellulose Phthalate, SR; Sustained Release, DR; Delay Release, Poly(MA-EA); Polymethyl Acrylic Co-Ethyl Acrylate, f-DR L-30 D-55; Femto-Delay Release Methyl Acrylic Acid Co-Ethyl Acrylate Polymer, MW; Molecular Weight, Tg; Glass Transition Temperature, SN2; Nucleophilic Substitution 2, EPR; Enhance Permeability and Retention, VEGF; Vascular Endothelial Growth Factor, RGD; Arginine-Glycine-Aspartic Acid, VCAM-1; Vascular Cell Adhesion Molecule-1, P; Coefficient of Permeability, PES; Polyether Sulfone, pHe; Extracellular pH, ζ-potential; Zeta potential, NTA; Nanoparticle Tracking Analysis, PB; Phosphate Buffer, DLS; Dynamic Light Scattering, AFM; Atomic Force Microscope, Log P; Partition Coefficient, MR; Molar Refractivity, tPSA; Topological Polar Surface Area, C log P; Calculated Partition Coefficient, CMR; Calculated Molar Refractivity, Log S; Solubility Coefficient, pka; Acid Dissociation Constant, DDAB; Dimethyl Dioctadecyl Ammonium Bromide, DOPE; Dioleoylphosphatidylethanolamine, GDP; Good Distribution Practice, RES; Reticuloendothelial System, PKU; Phenylketonuria, MS; Multiple Sclerosis, SLE; Systemic Lupus Erythematous, NASA; National Aeronautics and Space Administration, DOX; Doxorubicin, ADRs; Adverse Drug Reactions, SVM; Support Vector Machine, MDA; Malondialdehyde, TBARS; Thiobarbituric Acid Reactive Substances, CRP; C-Reactive Protein, CK; Creatine Kinase, LDH; Lactated Dehydrogenase, T2D; Type 2 Diabetes, PCB; Phycocyanobilin, PBP; Phycobiliproteins, PEB; Phycoerythrobilin, DPP-4; Dipeptidyl Peptidase-4, MTT; 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide, IL-2; Interleukin-2, IL-6; Interleukin-6, PRISMA; Preferred Reporting Items for Systematic Reviews and Meta-Analyses, STATA; Statistics, HepG2; Hepatoblastoma, HCT116; Colon Cancer Carcinoma, Kasumi-1; Acute Leukaemia, K562; Chronic Leukaemia, Se-PC; Selenium-Phycocyanin, MCF-7; Breast Cancer Adenocarcinoma, A375; Human Melanoma, RAS; Renin-Angiotensin System, IQP; Ile-Gln-Pro, VEP; Val-Glu-Pro, Mpro; Main Protease, PLpro; Papin-Like Protease, BMI; Body Mass Index, IC50; Inhibitory Concentration by 50%, LD50; Lethal Dose by 50%, PC12 Adh; Rat Pheochromocytoma Cells, RNS; Reactive Nitrogen Species, Hb1Ac; hemoglobin A1c.
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Affiliation(s)
- Omar Ashraf ElFar
- School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, Malaysia
| | - Nashiru Billa
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha, Qatar
| | - Hooi Ren Lim
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, Malaysia
| | - Kit Wayne Chew
- School of Energy and Chemical Engineering, Xiamen University Malaysia, Sepang, Malaysia
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Wai Yan Cheah
- Centre of Research in Development, Social and Environment (SEEDS), Faculty of Social Sciences and Humanities,Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia
| | | | | | - Pau Loke Show
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, Malaysia
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8
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Lam SF, Bishop KW, Mintz R, Fang L, Achilefu S. Calcium carbonate nanoparticles stimulate cancer cell reprogramming to suppress tumor growth and invasion in an organ-on-a-chip system. Sci Rep 2021; 11:9246. [PMID: 33927272 PMCID: PMC8084943 DOI: 10.1038/s41598-021-88687-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 04/15/2021] [Indexed: 02/08/2023] Open
Abstract
The acidic microenvironment of solid tumors induces the propagation of highly invasive and metastatic phenotypes. However, simulating these conditions in animal models present challenges that confound the effects of pH modulators on tumor progression. To recapitulate the tumor microenvironment and isolate the effect of pH on tumor viability, we developed a bifurcated microfluidic device that supports two different cell environments for direct comparison. RFP-expressing breast cancer cells (MDA-MB-231) were cultured in treatment and control chambers surrounded by fibrin, which received acid-neutralizing CaCO3 nanoparticles (nanoCaCO3) and cell culture media, respectively. Data analysis revealed that nanoCaCO3 buffered the pH within the normal physiological range and inhibited tumor cell proliferation compared to the untreated control (p < 0.05). Co-incubation of cancer cells and fibroblasts, followed by nanoCaCO3 treatment showed that the nanoparticles selectively inhibited the growth of the MDA-MB-231 cells and reduced cellular migration of these cells with no impact on the fibroblasts. Sustainable decrease in the intracellular pH of cancer cells treated with nanoCaCO3 indicates that the extracellular pH induced cellular metabolic reprogramming. These results suggest that the nanoCaCO3 can restrict the aggressiveness of tumor cells without affecting the growth and behavior of the surrounding stromal cells.
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Affiliation(s)
- Sandra F Lam
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Kevin W Bishop
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Rachel Mintz
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Lei Fang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | - Samuel Achilefu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA.
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA.
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9
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MCT4 Promotes Tumor Malignancy in F98 Glioma Cells. JOURNAL OF ONCOLOGY 2021; 2021:6655529. [PMID: 33936203 PMCID: PMC8060090 DOI: 10.1155/2021/6655529] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 03/16/2021] [Accepted: 03/25/2021] [Indexed: 12/31/2022]
Abstract
Monocarboxylate transporter 4 (MCT4, SLC16A3) is elevated under hypoxic conditions in many malignant tumors including gliomas. Moreover, MCT4 expression is associated with shorter overall survival. However, the functional consequences of MCT4 expression on the distinct hallmarks of cancer have not yet been explored at the cellular level. Here, we investigated the impact of MCT4 overexpression on proliferation, survival, cell death, migration, invasion, and angiogenesis in F98 glioma cells. Stable F98 glioma cell lines with MCT4 overexpression, normal expression, and knockdown were generated. Distinct hallmarks of cancer were examined using in silico analysis, various in vitro cell culture assays, and ex vivo organotypic rat brain slice culture model. Consistent with its function as lactate and proton exporter, MCT4 expression levels correlated inversely with extracellular pH and proportionally with extracellular lactate concentrations. Our results further indicate that MCT4 promotes proliferation and survival by altered cell cycle regulation and cell death mechanisms. Moreover, MCT4 overexpression enhances cell migration and invasiveness via reorganization of the actin cytoskeleton. Finally, MCT4 inhibition mitigates the induction of angiogenesis, suggesting that MCT4 also plays a crucial role in tumor-related angiogenesis. In summary, our data highlight MCT4/SLC16A3 as a key gene for distinct hallmarks of tumor malignancy in glioma cells.
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10
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Lee SH, Griffiths JR. How and Why Are Cancers Acidic? Carbonic Anhydrase IX and the Homeostatic Control of Tumour Extracellular pH. Cancers (Basel) 2020; 12:cancers12061616. [PMID: 32570870 PMCID: PMC7352839 DOI: 10.3390/cancers12061616] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 06/13/2020] [Accepted: 06/15/2020] [Indexed: 12/11/2022] Open
Abstract
The acidic tumour microenvironment is now recognized as a tumour phenotype that drives cancer somatic evolution and disease progression, causing cancer cells to become more invasive and to metastasise. This property of solid tumours reflects a complex interplay between cellular carbon metabolism and acid removal that is mediated by cell membrane carbonic anhydrases and various transport proteins, interstitial fluid buffering, and abnormal tumour-associated vessels. In the past two decades, a convergence of advances in the experimental and mathematical modelling of human cancers, as well as non-invasive pH-imaging techniques, has yielded new insights into the physiological mechanisms that govern tumour extracellular pH (pHe). In this review, we examine the mechanisms by which solid tumours maintain a low pHe, with a focus on carbonic anhydrase IX (CAIX), a cancer-associated cell surface enzyme. We also review the accumulating evidence that suggest a role for CAIX as a biological pH-stat by which solid tumours stabilize their pHe. Finally, we highlight the prospects for the clinical translation of CAIX-targeted therapies in oncology.
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Affiliation(s)
- Shen-Han Lee
- Department of Otorhinolaryngology, Hospital Sultanah Bahiyah, Jalan Langgar, Alor Setar 05460, Kedah, Malaysia
- Correspondence:
| | - John R. Griffiths
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK;
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11
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Vander Linden C, Corbet C. Therapeutic Targeting of Cancer Stem Cells: Integrating and Exploiting the Acidic Niche. Front Oncol 2019; 9:159. [PMID: 30941310 PMCID: PMC6433943 DOI: 10.3389/fonc.2019.00159] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 02/25/2019] [Indexed: 12/11/2022] Open
Abstract
Cancer stem cells (CSC) or tumor-initiating cells represent a small subpopulation of cells within the tumor bulk that share features with somatic stem cells, such as self-renewal and pluripotency. From a clinical point of view, CSC are thought to be the main drivers of tumor relapse in patients by supporting treatment resistance and dissemination to distant organs. Both genome instability and microenvironment-driven selection support tumor heterogeneity and enable the emergence of resistant cells with stem-like properties, when therapy is applied. Besides hypoxia and nutrient deprivation, acidosis is another selection barrier in the tumor microenvironment (TME) which provides a permissive niche to shape more aggressive and fitter cancer cell phenotypes. This review describes our current knowledge about the influence of the "acidic niche" on the stem-like phenotypic features of cancer cells. In addition, we briefly survey new therapeutic options that may help eradicate CSC by integrating and/or exploiting the acidic niche, and thereby contribute to prevent the occurrence of therapy resistance as well as metastatic dissemination.
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Affiliation(s)
| | - Cyril Corbet
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique, UCLouvain, Brussels, Belgium
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12
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Nakod PS, Kim Y, Rao SS. Biomimetic models to examine microenvironmental regulation of glioblastoma stem cells. Cancer Lett 2018; 429:41-53. [PMID: 29746930 DOI: 10.1016/j.canlet.2018.05.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/03/2018] [Accepted: 05/03/2018] [Indexed: 12/13/2022]
Abstract
Glioblastoma multiforme (GBM), a malignant brain tumor, is the deadliest form of human cancer with low survival rates because of its highly invasive nature. In recent years, there has been a growing appreciation for the role that glioblastoma stem cells (GSCs) play during tumorigenesis and tumor recurrence of GBM. GSCs are a specialized subset of GBM cells with stem cell-like features that contribute to tumor initiation and therapeutic resistance. Thus, to enhance therapeutic efficiency and improve survival, targeting GSCs and their microenvironmental niche appears to be a promising approach. To develop this approach, understanding GSC-microenvironment interactions is crucial. This review discusses various biomimetic model systems to understand the impact of biophysical, biochemical, and cellular microenvironmental cues on GSC behaviors. These models include two-dimensional or matrix-free environment models, engineered biomaterial-based three-dimensional models, co-culture models, and mouse and rat in vivo models. These systems have been used to study the effects of biophysical factors, modulation of signaling pathways, extracellular matrix components, and culture conditions on the GSC phenotype. The advantages and disadvantages of these model systems and their impact in the field of GSC research are discussed.
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Affiliation(s)
- Pinaki S Nakod
- Department of Chemical & Biological Engineering, The University of Alabama, Tuscaloosa, AL, USA
| | - Yonghyun Kim
- Department of Chemical & Biological Engineering, The University of Alabama, Tuscaloosa, AL, USA
| | - Shreyas S Rao
- Department of Chemical & Biological Engineering, The University of Alabama, Tuscaloosa, AL, USA.
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Mapping Extracellular pH of Gliomas in Presence of Superparamagnetic Nanoparticles: Towards Imaging the Distribution of Drug-Containing Nanoparticles and Their Curative Effect on the Tumor Microenvironment. CONTRAST MEDIA & MOLECULAR IMAGING 2017; 2017:3849373. [PMID: 29362558 PMCID: PMC5736903 DOI: 10.1155/2017/3849373] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/25/2017] [Accepted: 10/03/2017] [Indexed: 12/17/2022]
Abstract
Since brain's microvasculature is compromised in gliomas, intravenous injection of tumor-targeting nanoparticles containing drugs (D-NPs) and superparamagnetic iron oxide (SPIO-NPs) can deliver high payloads of drugs while allowing MRI to track drug distribution. However, therapeutic effect of D-NPs remains poorly investigated because superparamagnetic fields generated by SPIO-NPs perturb conventional MRI readouts. Because extracellular pH (pHe) is a tumor hallmark, mapping pHe is critical. Brain pHe is measured by biosensor imaging of redundant deviation in shifts (BIRDS) with lanthanide agents, by detecting paramagnetically shifted resonances of nonexchangeable protons on the agent. To test the hypothesis that BIRDS-based pHe readout remains uncompromised by presence of SPIO-NPs, we mapped pHe in glioma-bearing rats before and after SPIO-NPs infusion. While SPIO-NPs accumulation in the tumor enhanced MRI contrast, the pHe inside and outside the MRI-defined tumor boundary remained unchanged after SPIO-NPs infusion, regardless of the tumor type (9L versus RG2) or agent injection method (renal ligation versus coinfusion with probenecid). These results demonstrate that we can simultaneously and noninvasively image the specific location and the healing efficacy of D-NPs, where MRI contrast from SPIO-NPs can track their distribution and BIRDS-based pHe can map their therapeutic impact.
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Huang S, He P, Xu D, Li J, Peng X, Tang Y. Acidic stress induces apoptosis and inhibits angiogenesis in human bone marrow-derived endothelial progenitor cells. Oncol Lett 2017; 14:5695-5702. [PMID: 29113197 PMCID: PMC5661383 DOI: 10.3892/ol.2017.6947] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 11/30/2016] [Indexed: 11/12/2022] Open
Abstract
Bone marrow-derived endothelial progenitor cells (BM-EPCs) are exposed to acidotic environments in a variety of physiological and pathological conditions, including in tumors. However, the effect of acidosis on the function of BM-EPCs is still not fully understood. In the present study, BM-EPCs were isolated and cultured at an extracellular pH (pHe) of 6.5 or pHe 7.4 in vitro prior to various experiments being performed. Cellular proliferation, migration and tube formation ability were detected by DNA content quantification, Transwell assay and Matrigel-based angiogenesis assay. ELISA and western blot analysis measured protein secretion and expression, respectively. The results demonstrated that BM-EPCs cultured at pHe 6.5 compared with at pHe 7.4 demonstrated: Induced apoptosis; inhibited cellular proliferation, migration and adhesion; markedly reduced vascular endothelial growth factor (VEGF) expression; and the capacity to incorporate into vascular networks. Acidic pHe 6.5 induced ratio expression of B-cell lymphoma 2 (Bcl2)/Bcl2 associated X-protein (Bax), which in turn induced apoptosis, and inhibited cellular proliferation and other functional activities, with involvement of activation of VEGF receptor 2, protein kinase B and p38 mitogen activated protein kinase. These observations raise the possibility that the acidic extracellular environment may perform an important role in the vasculogenesis of BM-EPCs in tumor microenvironments. Therefore, culturing cancer cells at a lower pH that simulates endogenous tumor conditions may improve retention of the cellular heterogeneity identified in tumors.
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Affiliation(s)
- Shuai Huang
- Department of Orthopedic Surgery, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Peiheng He
- Department of Orthopedic Surgery, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Dongliang Xu
- Department of Orthopedic Surgery, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Jinglei Li
- Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, Guangzhou, Guangdong 510080, P.R. China
| | - Xinsheng Peng
- Department of Orthopedic Surgery, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Yubo Tang
- Department of Pharmacy, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510080, P.R. China
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15
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Stock C, Pedersen SF. Roles of pH and the Na +/H + exchanger NHE1 in cancer: From cell biology and animal models to an emerging translational perspective? Semin Cancer Biol 2016; 43:5-16. [PMID: 28007556 DOI: 10.1016/j.semcancer.2016.12.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 12/10/2016] [Indexed: 01/30/2023]
Abstract
Acidosis is characteristic of the solid tumor microenvironment. Tumor cells, because they are highly proliferative and anabolic, have greatly elevated metabolic acid production. To sustain a normal cytosolic pH homeostasis they therefore need to either extrude excess protons or to neutralize them by importing HCO3-, in both cases causing extracellular acidification in the poorly perfused tissue microenvironment. The Na+/H+ exchanger isoform 1 (NHE1) is a ubiquitously expressed acid-extruding membrane transport protein, and upregulation of its expression and/or activity is commonly correlated with tumor malignancy. The present review discusses current evidence on how altered pH homeostasis, and in particular NHE1, contributes to tumor cell motility, invasion, proliferation, and growth and facilitates evasion of chemotherapeutic cell death. We summarize data from in vitro studies, 2D-, 3D- and organotypic cell culture, animal models and human tissue, which collectively point to pH-regulation in general, and NHE1 in particular, as potential targets in combination chemotherapy. Finally, we discuss the possible pitfalls, side effects and cellular escape mechanisms that need to be considered in the process of translating the plethora of basic research data into a clinical setting.
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Affiliation(s)
- Christian Stock
- Department of Gastroenterology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Stine Falsig Pedersen
- Department of Biology, Section for Cell Biology and Physiology, University of Copenhagen, Universitetsparken 13, 2100 Copenhagen, Denmark.
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16
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Rocha PRF, Medeiros MCR, Kintzel U, Vogt J, Araújo IM, Mestre ALG, Mailänder V, Schlett P, Dröge M, Schneider L, Biscarini F, de Leeuw DM, Gomes HL. Extracellular electrical recording of pH-triggered bursts in C6 glioma cell populations. SCIENCE ADVANCES 2016; 2:e1600516. [PMID: 28028533 PMCID: PMC5182051 DOI: 10.1126/sciadv.1600516] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 11/18/2016] [Indexed: 05/29/2023]
Abstract
Glioma patients often suffer from epileptic seizures because of the tumor's impact on the brain physiology. Using the rat glioma cell line C6 as a model system, we performed long-term live recordings of the electrical activity of glioma populations in an ultrasensitive detection method. The transducer exploits large-area electrodes that maximize double-layer capacitance, thus increasing the sensitivity. This strategy allowed us to record glioma electrical activity. We show that although glioma cells are nonelectrogenic, they display a remarkable electrical burst activity in time. The low-frequency current noise after cell adhesion is dominated by the flow of Na+ ions through voltage-gated ion channels. However, after an incubation period of many hours, the current noise markedly increased. This electric bursting phenomenon was not associated with apoptosis because the cells were viable and proliferative during the period of increased electric activity. We detected a rapid cell culture medium acidification accompanying this event. By using specific inhibitors, we showed that the electrical bursting activity was prompted by extracellular pH changes, which enhanced Na+ ion flux through the psalmotoxin 1-sensitive acid-sensing ion channels. Our model of pH-triggered bursting was unambiguously supported by deliberate, external acidification of the cell culture medium. This unexpected, acidosis-driven electrical activity is likely to directly perturb, in vivo, the functionality of the healthy neuronal network in the vicinity of the tumor bulk and may contribute to seizures in glioma patients.
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Affiliation(s)
- Paulo R. F. Rocha
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Maria C. R. Medeiros
- Instituto de Telecomunicações, Departamento de Engenharia Electrotécnica e de Computadores, Universidade de Coimbra, 3030-290 Coimbra, Portugal
| | - Ulrike Kintzel
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Johannes Vogt
- Institute of Microanatomy and Neurobiology, University Medical Center Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany
| | - Inês M. Araújo
- Department of Biomedical Sciences and Medicine, University of Algarve, 8005-139 Faro, Portugal
- Centre for Biomedical Research, University of Algarve, 8005-139 Faro, Portugal
| | - Ana L. G. Mestre
- Instituto de Telecomunicações, Avenida Rovisco, Pais 1, 1049-001 Lisboa, Portugal
- Universidade do Algarve, Faculdade de Ciências e Tecnologia, 8005-139 Faro, Portugal
| | - Volker Mailänder
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
- Dermatology Clinic, University Medicine of the Johannes-Gutenberg Universität Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany
| | - Paul Schlett
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Melanie Dröge
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Leonid Schneider
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Fabio Biscarini
- Department of Life Sciences, Università di Modena e Reggio Emilia, Via Campi 103, I-41125 Modena, Italy
| | - Dago M. de Leeuw
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
- Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft, Netherlands
| | - Henrique L. Gomes
- Instituto de Telecomunicações, Avenida Rovisco, Pais 1, 1049-001 Lisboa, Portugal
- Universidade do Algarve, Faculdade de Ciências e Tecnologia, 8005-139 Faro, Portugal
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17
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Lee G, Hall RR, Ahmed AU. Cancer Stem Cells: Cellular Plasticity, Niche, and its Clinical Relevance. JOURNAL OF STEM CELL RESEARCH & THERAPY 2016; 6:363. [PMID: 27891292 PMCID: PMC5123595 DOI: 10.4172/2157-7633.1000363] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cancer handles an estimated 7.6 million deaths worldwide per annum. A recent theory focuses on the role Cancer Stem Cells (CSCs) in driving tumorigenesis and disease progression. This theory hypothesizes that a population of the tumor cell with similar functional and phenotypic characteristics as normal tissue stem cells are responsible for formation and advancement of many human cancers. The CSCs subpopulation can differentiate into non-CSC tumor cells and promote phenotypic and functional heterogeneity within the tumor. The presence of CSCs has been reported in a number of human cancers including blood, breast, brain, colon, lung, pancreas prostate and liver. Although the origin of CSCs remains a mystery, recent reports suggest that the phenotypic characteristics of CSCs may be plastic and are influenced by the microenvironment specific for the individual tumor. Such factors unique to each tumor preserve the dynamic balance between CSCs to non-CSCs cell fate, as well as maintain the proper equilibrium. Alternating such equilibrium via dedifferentiation can result in aggressiveness, as CSCs are considered to be more resistant to the conventional cancer treatments of chemotherapy and radiation. Understanding how the tumoral microenvironment affects the plasticity driven CSC niche will be critical for developing a more effective treatment for cancer by eliminating its aggressive and recurring nature that now is believed to be perpetuated by CSCs.
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Affiliation(s)
- Gina Lee
- Department of Neurological Surgery, Northwestern University, Chicago, Illinois, USA
| | - Robert R Hall
- Department of Neurological Surgery, Northwestern University, Chicago, Illinois, USA
| | - Atique U Ahmed
- Department of Neurological Surgery, Northwestern University, Chicago, Illinois, USA
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18
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Mesoporous silica nanoparticles with bilayer coating of poly(acrylic acid-co-itaconic acid) and human serum albumin (HSA): A pH-sensitive carrier for gemcitabine delivery. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 61:782-90. [DOI: 10.1016/j.msec.2015.12.096] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 12/20/2015] [Accepted: 12/31/2015] [Indexed: 11/22/2022]
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19
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Cationizable lipid micelles as vehicles for intraarterial glioma treatment. J Neurooncol 2016; 128:21-28. [PMID: 26903015 DOI: 10.1007/s11060-016-2088-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 02/15/2016] [Indexed: 12/18/2022]
Abstract
The relative abundance of anionic lipids on the surface of endothelia and on glioma cells suggests a workable strategy for selective drug delivery by utilizing cationic nanoparticles. Furthermore, the extracellular pH of gliomas is relatively acidic suggesting that tumor selectivity could be further enhanced if nanoparticles can be designed to cationize in such an environment. With these motivating hypotheses the objective of this study was to determine whether nanoparticulate (20 nm) micelles could be designed to improve their deposition within gliomas in an animal model. To test this, we performed intra-arterial injection of micelles labeled with an optically quantifiable dye. We observed significantly greater deposition (end-tissue concentration) of cationizable micelles as compared to non-ionizable micelles in the ipsilateral hemisphere of normal brains. More importantly, we noted enhanced deposition of cationizable as compared to non-ionizable micelles in glioma tissue as judged by semiquantitative fluorescence analysis. Micelles were generally able to penetrate to the core of the gliomas tested. Thus we conclude that cationizable micelles may be constructed as vehicles for facilitating glioma-selective delivery of compounds after intraarterial injection.
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20
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Ahmad H, Alam MM, Rahman MA, Minami H, Gafur MA. Epoxide Functional Temperature-Sensitive Semi-IPN Hydrogel Microspheres for Isolating Inorganic Nanoparticles. ADVANCES IN POLYMER TECHNOLOGY 2016. [DOI: 10.1002/adv.21645] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- H. Ahmad
- Department of Chemistry; Rajshahi University; Rajshahi 6205 Bangladesh
| | - M. M. Alam
- Department of Chemistry; Rajshahi University; Rajshahi 6205 Bangladesh
| | - M. A. Rahman
- Department of Chemistry; Rajshahi University; Rajshahi 6205 Bangladesh
| | - H. Minami
- Graduate School of Engineering; Kobe University; Kobe 657-8501 Japan
| | - M. A. Gafur
- Pilot Plant and Process Development Centre; BCSIR; Dhaka 1205 Bangladesh
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21
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Shirmanova MV, Druzhkova IN, Lukina MM, Matlashov ME, Belousov VV, Snopova LB, Prodanetz NN, Dudenkova VV, Lukyanov SA, Zagaynova EV. Intracellular pH imaging in cancer cells in vitro and tumors in vivo using the new genetically encoded sensor SypHer2. Biochim Biophys Acta Gen Subj 2015; 1850:1905-11. [PMID: 25964069 DOI: 10.1016/j.bbagen.2015.05.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 04/30/2015] [Accepted: 05/04/2015] [Indexed: 02/04/2023]
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22
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Tapmeier TT, Moshnikova A, Beech J, Allen D, Kinchesh P, Smart S, Harris A, McIntyre A, Engelman DM, Andreev OA, Reshetnyak YK, Muschel RJ. The pH low insertion peptide pHLIP Variant 3 as a novel marker of acidic malignant lesions. Proc Natl Acad Sci U S A 2015; 112:9710-5. [PMID: 26195776 PMCID: PMC4534280 DOI: 10.1073/pnas.1509488112] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Current strategies for early detection of breast and other cancers are limited in part because some lesions identified as potentially malignant do not develop into aggressive tumors. Acid pH has been suggested as a key characteristic of aggressive tumors that might distinguish aggressive lesions from more indolent pathology. We therefore investigated the novel class of molecules, pH low insertion peptides (pHLIPs), as markers of low pH in tumor allografts and of malignant lesions in a mouse model of spontaneous breast cancer, BALB/neu-T. pHLIP Variant 3 (Var3) conjugated with fluorescent Alexa546 was shown to insert into tumor spheroids in a sequence-specific manner. Its signal reflected pH in murine tumors. It was induced by carbonic anhydrase IX (CAIX) overexpression and inhibited by acetazolamide (AZA) administration. By using (31)P magnetic resonance spectroscopy (MRS), we demonstrated that pHLIP Var3 was retained in tumors of pH equal to or less than 6.7 but not in tissues of higher pH. In BALB/neu-T mice at different stages of the disease, the fluorescent signal from pHLIP Var3 marked cancerous lesions with a very low false-positive rate. However, only ∼60% of the smallest lesions retained a pHLIP Var3 signal, suggesting heterogeneity in pH. Taken together, these results show that pHLIP can identify regions of lower pH, allowing for its development as a theranostic tool for clinical applications.
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Affiliation(s)
- Thomas T Tapmeier
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Anna Moshnikova
- Physics Department, University of Rhode Island, Kingston, RI 02881
| | - John Beech
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Danny Allen
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Paul Kinchesh
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Sean Smart
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Adrian Harris
- Weatherall Institute of Molecular Medicine, Department of Oncology, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Alan McIntyre
- Weatherall Institute of Molecular Medicine, Department of Oncology, University of Oxford, Oxford OX3 9DS, United Kingdom; Cancer Biology, Division of Cancer and Stem Cells, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom
| | - Donald M Engelman
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520
| | - Oleg A Andreev
- Physics Department, University of Rhode Island, Kingston, RI 02881
| | | | - Ruth J Muschel
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom;
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Pacheco-Torres J, Mukherjee N, Walko M, López-Larrubia P, Ballesteros P, Cerdan S, Kocer A. Image guided drug release from pH-sensitive Ion channel-functionalized stealth liposomes into an in vivo glioblastoma model. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2015; 11:1345-54. [DOI: 10.1016/j.nano.2015.03.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 03/03/2015] [Accepted: 03/29/2015] [Indexed: 01/11/2023]
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Paech D, Burth S, Windschuh J, Meissner JE, Zaiss M, Eidel O, Kickingereder P, Nowosielski M, Wiestler B, Sahm F, Floca RO, Neumann JO, Wick W, Heiland S, Bendszus M, Schlemmer HP, Ladd ME, Bachert P, Radbruch A. Nuclear Overhauser Enhancement imaging of glioblastoma at 7 Tesla: region specific correlation with apparent diffusion coefficient and histology. PLoS One 2015; 10:e0121220. [PMID: 25789657 PMCID: PMC4366097 DOI: 10.1371/journal.pone.0121220] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/30/2015] [Indexed: 01/24/2023] Open
Abstract
OBJECTIVE To explore the correlation between Nuclear Overhauser Enhancement (NOE)-mediated signals and tumor cellularity in glioblastoma utilizing the apparent diffusion coefficient (ADC) and cell density from histologic specimens. NOE is one type of chemical exchange saturation transfer (CEST) that originates from mobile macromolecules such as proteins and might be associated with tumor cellularity via altered protein synthesis in proliferating cells. PATIENTS AND METHODS For 15 patients with newly diagnosed glioblastoma, NOE-mediated CEST-contrast was acquired at 7 Tesla (asymmetric magnetization transfer ratio (MTRasym) at 3.3ppm, B1 = 0.7 μT). Contrast enhanced T1 (CE-T1), T2 and diffusion-weighted MRI (DWI) were acquired at 3 Tesla and coregistered. The T2 edema and the CE-T1 tumor were segmented. ADC and MTRasym values within both regions of interest were correlated voxelwise yielding the correlation coefficient rSpearman (rSp). In three patients who underwent stereotactic biopsy, cell density of 12 specimens per patient was correlated with corresponding MTRasym and ADC values of the biopsy site. RESULTS Eight of 15 patients showed a weak or moderate positive correlation of MTRasym and ADC within the T2 edema (0.16≤rSp≤0.53, p<0.05). Seven correlations were statistically insignificant (p>0.05, n = 4) or yielded rSp≈0 (p<0.05, n = 3). No trend towards a correlation between MTRasym and ADC was found in CE-T1 tumor (-0.31<rSp<0.28, p<0.05, n = 9; p>0.05, n = 6). The biopsy-analysis within CE-T1 tumor revealed a strong positive correlation between tumor cellularity and MTRasym values in two of the three patients (rSppatient3 = 0.69 and rSppatient15 = 0.87, p<0.05), while the correlation of ADC and cellularity was heterogeneous (rSppatient3 = 0.545 (p = 0.067), rSppatient4 = -0.021 (p = 0.948), rSppatient15 = -0.755 (p = 0.005)). DISCUSSION NOE-imaging is a new contrast promising insight into pathophysiologic processes in glioblastoma regarding cell density and protein content, setting itself apart from DWI. Future studies might be based on the assumption that NOE-mediated CEST visualizes cellularity more accurately than ADC, especially in the CE-T1 tumor region.
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Affiliation(s)
- Daniel Paech
- Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany
- Neurooncologic Imaging, Department of Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Sina Burth
- Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany
- Neurooncologic Imaging, Department of Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Johannes Windschuh
- Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Jan-Eric Meissner
- Neurooncologic Imaging, Department of Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
- Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Moritz Zaiss
- Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Oliver Eidel
- Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany
| | - Philipp Kickingereder
- Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany
| | - Martha Nowosielski
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
| | - Benedikt Wiestler
- Department of Neurology, University of Heidelberg Medical Center, Heidelberg, Germany
| | - Felix Sahm
- Department of Neuropathology, University of Heidelberg Medical Center, Heidelberg, Germany
| | - Ralf Omar Floca
- Department of Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Jan-Oliver Neumann
- Department of Neurosurgery, University of Heidelberg Medical Center, Heidelberg, Germany
| | - Wolfgang Wick
- Department of Neurology, University of Heidelberg Medical Center, Heidelberg, Germany
| | - Sabine Heiland
- Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany
| | - Martin Bendszus
- Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany
| | - Heinz-Peter Schlemmer
- Department of Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Mark Edward Ladd
- Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Peter Bachert
- Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Alexander Radbruch
- Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany
- Neurooncologic Imaging, Department of Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
- * E-mail:
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25
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Thakur B, Jayakumar S, Sawant SN. Probing extracellular acidity of live cells in real time for cancer detection and monitoring anti-cancer drug activity. Chem Commun (Camb) 2015; 51:7015-8. [DOI: 10.1039/c5cc01445j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A multifunctional platform is presented which (a) allows determination of extracellular pH in real time, (b) detects cancer cells, down to 5 cells, and (c) enables evaluating the efficacy of glycolysis inhibiting drugs.
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Affiliation(s)
| | - S. Jayakumar
- Radiation Biology & Health Sciences Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
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26
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Pourjavadi A, Tehrani ZM, Hosseini SH. Dendritic magnetite decorated by pH-responsive PEGylated starch: a smart multifunctional nanocarrier for the triggered release of anti-cancer drugs. RSC Adv 2015. [DOI: 10.1039/c5ra04040j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the present study, we designed a pH-responsive drug nanocarrier based on polyamidoamine-modified Fe3O4 nanoparticles coated by PEGylated starch-co-poly(acrylic acid).
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Affiliation(s)
- Ali Pourjavadi
- Polymer Research Laboratory
- Department of Chemistry
- Sharif University of Technology
- Tehran
- Iran
| | - Zahra Mazaheri Tehrani
- Polymer Research Laboratory
- Department of Chemistry
- Sharif University of Technology
- Tehran
- Iran
| | - Seyed Hassan Hosseini
- Polymer Research Laboratory
- Department of Chemistry
- Sharif University of Technology
- Tehran
- Iran
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27
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Corbet C, Draoui N, Polet F, Pinto A, Drozak X, Riant O, Feron O. The SIRT1/HIF2α axis drives reductive glutamine metabolism under chronic acidosis and alters tumor response to therapy. Cancer Res 2014; 74:5507-19. [PMID: 25085245 DOI: 10.1158/0008-5472.can-14-0705] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Extracellular tumor acidosis largely results from an exacerbated glycolytic flux in cancer and cancer-associated cells. Conversely, little is known about how tumor cells adapt their metabolism to acidosis. Here, we demonstrate that long-term exposure of cancer cells to acidic pH leads to a metabolic reprogramming toward glutamine metabolism. This switch is triggered by the need to reduce the production of protons from glycolysis and further maintained by the NAD(+)-dependent increase in SIRT1 deacetylase activity to ensure intracellular pH homeostasis. A consecutive increase in HIF2α activity promotes the expression of various transporters and enzymes supporting the reductive and oxidative glutamine metabolism, whereas a reduction in functional HIF1α expression consolidates the inhibition of glycolysis. Finally, in vitro and in vivo experiments document that acidosis accounts for a net increase in tumor sensitivity to inhibitors of SIRT1 and glutaminase GLS1. These findings highlight the influence that tumor acidosis and metabolism exert on each other.
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Affiliation(s)
- Cyril Corbet
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain, Brussels, Belgium
| | - Nihed Draoui
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain, Brussels, Belgium
| | - Florence Polet
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain, Brussels, Belgium
| | - Adan Pinto
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain, Brussels, Belgium
| | - Xavier Drozak
- Molecules, Solids and Reactivity (MOST), Institute of Condensed Matter and Nanosciences (IMCN), Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Olivier Riant
- Molecules, Solids and Reactivity (MOST), Institute of Condensed Matter and Nanosciences (IMCN), Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Olivier Feron
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain, Brussels, Belgium.
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28
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Adochite RC, Moshnikova A, Carlin SD, Guerrieri RA, Andreev OA, Lewis JS, Reshetnyak YK. Targeting breast tumors with pH (low) insertion peptides. Mol Pharm 2014; 11:2896-905. [PMID: 25004202 PMCID: PMC4123937 DOI: 10.1021/mp5002526] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Extracellular acidity is associated with tumor progression. Elevated glycolysis and acidosis promote the appearance of aggressive malignant cells with enhanced multidrug resistance. Thus, targeting of tumor acidity can open new avenues in diagnosis and treatment of aggressive tumors and targeting metastatic cancers cells within a tumor. pH (low) insertion peptides (pHLIPs) belong to the class of pH-sensitive agents capable of delivering imaging and/or therapeutic agents to cancer cells within tumors. Here, we investigated targeting of highly metastatic 4T1 mammary tumors and spontaneous breast tumors in FVB/N-Tg (MMTV-PyMT)634Mul transgenic mice with three fluorescently labeled pHLIP variants including well-characterized WT-pHLIP and, recently introduced, Var3- and Var7-pHLIPs. The Var3- and Var7-pHLIPs constructs have faster blood clearance than the parent WT-pHLIP. All pHLIPs demonstrated excellent targeting of the above breast tumor models with tumor accumulation increasing over 4 h postinjection. Staining of nonmalignant stromal tissues in transgenic mice was minimal. The pHLIPs distribution in tumors showed colocalization with 2-deoxyglucose and the hypoxia marker, Pimonidazole. The highest degree of colocalization of fluorescent pHLIPs was shown to be with lactate dehydrogenase A, which is related to lactate production and acidification of tumors. In sum, the pHLIP-based targeting of breast cancer presents an opportunity to monitor metabolic changes, and to selectively deliver imaging and therapeutic agents to tumors.
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Affiliation(s)
- Ramona-Cosmina Adochite
- Physics Department, University of Rhode Island , 2 Lippitt Road, Kingston, Rhode Island 02881, United States
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29
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Hu X, Wang Y, Peng B. Chitosan-capped mesoporous silica nanoparticles as pH-responsive nanocarriers for controlled drug release. Chem Asian J 2013; 9:319-27. [PMID: 24115568 DOI: 10.1002/asia.201301105] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Indexed: 11/08/2022]
Abstract
Herein, we present a straightforward synthesis of pH-responsive chitosan-capped mesoporous silica nanoparticles (MSNs). These MCM-41-type MSNs could be used as nanocapsules to accommodate guest molecules. Subsequently, (3-glycidyloxypropyl)trimethoxysilane was grafted onto the surface of the MSNs, which served as a bridge to link between MSNs and chitosan, which is ubiquitous in nature and commercially available. Owing to the pH-responsive and biocompatible features of chitosan, the loading and release of an anti-cancer drug, doxorubicin hydrochloride, were carried out in vitro, in which the composite chitosan-capped MSNs (CS-MSNs) showed excellent environmental response. As the pH value of the media decreased, the degree of drug release correspondingly increased. Moreover, thanks to the perfect biocompatibility of chitosan, the CS-MSNs exhibited lower cytotoxicity than that of the naked MSNs in an MTT assay. In addition, the in vitro kill potency against MCF-7 breast-cancer cells was enhanced over time, as well as with increasing concentration of the drug-loaded CS-MSNs. These results indicate that CS-MSNs are promising candidates for pH-responsive drug delivery in cancer therapy.
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Affiliation(s)
- Xiaoxi Hu
- Scholl of Chemistry and Chemical Engineering, Qinzhou University, Qinzhou 535000 (People's Republic of China).
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30
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Vaupel P. Tumor oxygenation: an appraisal of past and present concepts and a look into the future : Arisztid G. B. Kovách Lecture. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 789:229-236. [PMID: 23852499 DOI: 10.1007/978-1-4614-7411-1_31] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Since 1970, the multifactorial pathogenesis of the deficient and heterogeneous oxygenation of transplanted murine tumors and of human cancers (including parameters determining oxygen delivery, e.g., blood flow, diffusion geometry, oxygen transport capacity of the blood) has been investigated in vivo. Hypoxia and/or anoxia was quantitatively assessed and characterized using microtechniques and special preclinical tumor models. Hypoxia subtypes were identified, and critical supply conditions were theoretically analyzed. In the 1980s, first experiments on humans were carried out in cancers of the rectum and of the oral cavity. In the 1990s, the clinical investigations were carried out on cancers of the breast and of the uterine cervix, clearly showing that hypoxia is a hallmark of locally advanced human tumors. In multivariate analysis, hypoxia was found to be an independent, adverse prognostic factor for patient survival due to hypoxia-driven malignant progression and hypoxia-associated resistance to anticancer therapy.
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Affiliation(s)
- Peter Vaupel
- Department of Radiotherapy and Radiooncology, Klinikum rechts der Isar, Technical University, Ismaninger Strasse 22, 81675, Munich, Germany.
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31
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Prevention of nodal metastases in breast cancer following the lymphatic migration of paclitaxel-loaded expansile nanoparticles. Biomaterials 2012; 34:1810-9. [PMID: 23228419 DOI: 10.1016/j.biomaterials.2012.11.038] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 11/20/2012] [Indexed: 02/05/2023]
Abstract
Although breast cancer patients with localized disease exhibit an excellent long-term prognosis, up to 40% of patients treated with local resection alone may harbor occult nodal metastatic disease leading to increased locoregional recurrence and decreased survival. Given the potential for targeted drug delivery to result in more efficacious locoregional control with less morbidity, the current study assessed the ability of drug-loaded polymeric expansile nanoparticles (eNP) to migrate from the site of tumor to regional lymph nodes, locally deliver a chemotherapeutic payload, and prevent primary tumor growth as well as lymph node metastases. Expansile nanoparticles entered tumor cells and paclitaxel-loaded eNP (Pax-eNP) exhibited dose-dependent cytotoxicity in vitro and significantly decreased tumor doubling time in vivo against human triple negative breast cancer in both microscopic and established murine breast cancer models. Furthermore, migration of Pax-eNP to axillary lymph nodes resulted in higher intranodal paclitaxel concentrations and a significantly lower incidence of lymph node metastases. These findings demonstrate that lymphatic migration of drug-loaded eNP provides regionally targeted delivery of chemotherapy to both decrease local tumor growth and strategically prevent the development of nodal metastases within the regional tumor-draining lymph node basin.
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32
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pHLIP and acidity as a universal biomarker for cancer. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2012; 85:29-35. [PMID: 22461741 PMCID: PMC3313536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Of great importance to clinical cancer diagnosis is the use of organic biomarkers. The detection of RNA, DNA, and protein antigen are all established methods for identifying specific cancer types and instrumental in promoting greater survivorship of the patient. Despite many decades of intense cancer research, we have yet to identify a "universal" protein or nucleic acid that allows us to diagnose more than a small subset of cancers at a time. In this review, we examine the use of localized cellular acidity as a universal marker for solid tumors, outlining some successes with a small peptide we call pHLIP, a pH-sensitive biosensor that allows us to label tumor tissue in live mice.
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33
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Xu T, Su H, Ganapathy S, Yuan ZM. Modulation of autophagic activity by extracellular pH. Autophagy 2011; 7:1316-22. [PMID: 21997366 DOI: 10.4161/auto.7.11.17785] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Reprogramming energy metabolism from oxidative phosphorylation to aerobic glycolysis, a common feature of human cancer, is associated with a relative acidic tumor microenvironment which can sometimes be further accentuated by hypoxia operating within most solid tumors. We found that alteration of extracellular pH induces marked and rapid changes of autophagic activity. Interestingly, acidic and basic conditions induced completely opposite effect on autophagy, with its activity suppressed at lower pH whereas stimulated at higher pH. Gene knockdown experiments indicated that pH induced-autophagy requires Beclin 1, Vps34 and Atg5, key components of the autophagy pathway. Of note, an acidic condition not only inhibits the basal but also blocks the starvation-induced autophagy activity. Significantly, examination of different areas of tumor mass revealed a lower autophagic activity within the inner region than the outer region. These findings have important implications on the connections between autophagy and cancer as well as a wide range of other physiological and pathological processes.
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Affiliation(s)
- Teng Xu
- Department of Radiation Oncology, Cancer Therapy & Research Center, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
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34
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Hattingen E, Jurcoane A, Bähr O, Rieger J, Magerkurth J, Anti S, Steinbach JP, Pilatus U. Bevacizumab impairs oxidative energy metabolism and shows antitumoral effects in recurrent glioblastomas: a 31P/1H MRSI and quantitative magnetic resonance imaging study. Neuro Oncol 2011; 13:1349-63. [PMID: 21890539 DOI: 10.1093/neuonc/nor132] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Bevacizumab shows unprecedented rates of response in recurrent glioblastomas (GBM), but the detailed mechanisms are still unclear. We employed in vivo magnetic resonance spectroscopic imaging (MRSI) and quantitative magnetic resonance imaging to investigate whether bevacizumab alters oxygen and energy metabolism and whether this effect has antitumoral activity in recurrent GBM. (31)P and (1)H MRSI, apparent diffusion coefficient (ADC), and high-resolution T2 and T2' mapping (indirect marker of oxygen extraction) were investigated in 16 patients with recurrent GBM at 3 Tesla before and 1.5-2 months after initiation of therapy with bevacizumab. Changes of metabolite concentrations and of the quantitative values in the tumor and normal appearing brain tissue were calculated. The Wilcoxon signed-ranks test was used to evaluate differences for tumor/edema versus control as well as changes before versus after commencement of therapy. Survival analyses were performed for significant parameters. Tumor T2', pH, ADC, and T2 decreased significantly in patients responding to bevacizumab therapy (n = 10). Patients with at least 25% T2' decrease during treatment showed longer progression-free and overall survival durations. Levels of high-energy metabolites were lower at baseline; these persisted under therapy. Glycerophosphoethanolamine as catabolic phospholipid metabolite increased in responders. The MRSI data support the hypothesis that bevacizumab induces relative tumor hypoxia (T2' decrease) and affects energy homeostasis in recurrent GBM, suggesting that bevacizumab impairs vascular function. The antiangiogenic effect of bevacizumab is predictive of better outcome and seems to induce antitumoral activity in the responding GBMs.
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Affiliation(s)
- Elke Hattingen
- Goethe University Frankfurt, Institute of Neuroradiology, Schleusenweg 2-16 (Haus 95), 60528 Frankfurt/M, Germany.
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35
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Deng Z, Zhen Z, Hu X, Wu S, Xu Z, Chu PK. Hollow chitosan–silica nanospheres as pH-sensitive targeted delivery carriers in breast cancer therapy. Biomaterials 2011; 32:4976-86. [DOI: 10.1016/j.biomaterials.2011.03.050] [Citation(s) in RCA: 220] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 03/21/2011] [Indexed: 11/17/2022]
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36
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Hjelmeland AB, Wu Q, Heddleston JM, Choudhary GS, MacSwords J, Lathia JD, McLendon R, Lindner D, Sloan A, Rich JN. Acidic stress promotes a glioma stem cell phenotype. Cell Death Differ 2010; 18:829-40. [PMID: 21127501 DOI: 10.1038/cdd.2010.150] [Citation(s) in RCA: 285] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Malignant gliomas are lethal cancers that display cellular hierarchies with cancer stem cells at the apex. Glioma stem cells (GSCs) are not uniformly distributed, but rather located in specialized niches, suggesting that the cancer stem cell phenotype is regulated by the tumor microenvironment. Indeed, recent studies show that hypoxia and its molecular responses regulate cancer stem cell maintenance. We now demonstrate that acidic conditions, independent of restricted oxygen, promote the expression of GSC markers, self-renewal and tumor growth. GSCs exert paracrine effects on tumor growth through elaboration of angiogenic factors, and low pH conditions augment this expression associated with induction of hypoxia inducible factor 2α (HIF2α), a GSC-specific regulator. Induction of HIF2α and other GSC markers by acidic stress can be reverted by elevating pH in vitro, suggesting that raising intratumoral pH may be beneficial for targeting the GSC phenotype. Together, our results suggest that exposure to low pH promotes malignancy through the induction of a cancer stem cell phenotype, and that culturing cancer cells at lower pH reflective of endogenous tumor conditions may better retain the cellular heterogeneity found in tumors.
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Affiliation(s)
- A B Hjelmeland
- Departments of Stem Cell Biology and Regenerative Medicine, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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37
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Vaupel PW, Kelleher DK. Pathophysiological and vascular characteristics of tumours and their importance for hyperthermia: heterogeneity is the key issue. Int J Hyperthermia 2010; 26:211-23. [PMID: 20345270 DOI: 10.3109/02656731003596259] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Tumour blood flow before and during clinically relevant mild hyperthermia exhibits pronounced heterogeneity. Flow changes upon heating are not predictable and are both spatially and temporally highly variable. Flow increases may result in improved heat dissipation to the extent that therapeutically relevant tissue temperatures may not be achieved. This holds especially true for tumours or tumour regions in which flow rates are substantially higher than in the surrounding normal tissues. Changes in tumour oxygenation tend to reflect alterations in blood flow upon hyperthermia. An initial improvement in the oxygenation status, followed by a return to baseline levels (or even a drop to below baseline at high thermal doses) has been reported for some tumours, whereas a predictable and universal occurrence of sustained increases in O(2) tensions upon mild hyperthermia is questionable and still needs to be verified in the clinical setting. Clarification of the pathogenetic mechanisms behind possible sustained increases is mandatory. High-dose hyperthermia leads to a decrease in the extracellular and intracellular pH and a deterioration of the energy status, both of which are known to be parameters capable of acting as direct sensitisers and thus pivotal factors in hyperthermia treatment. The role of the tumour microcirculatory function, hypoxia, acidosis and energy status is complex and is further complicated by a pronounced heterogeneity. These latter aspects require additional critical evaluation in clinically relevant tumour models in order for their impact on the response to heat to be clarified.
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Affiliation(s)
- Peter W Vaupel
- Department of Radiotherapy and Radiooncology, Klinikum rechts der Isar, Technical University, Munich, Germany
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38
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Vaupel P. Pathophysiology of Solid Tumors. THE IMPACT OF TUMOR BIOLOGY ON CANCER TREATMENT AND MULTIDISCIPLINARY STRATEGIES 2009. [DOI: 10.1007/978-3-540-74386-6_4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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39
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Shen Y, Tang H, Radosz M, Van Kirk E, Murdoch WJ. pH-responsive nanoparticles for cancer drug delivery. Methods Mol Biol 2008; 437:183-216. [PMID: 18369970 DOI: 10.1007/978-1-59745-210-6_10] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Solid tumors have an acidic extracellular environment and an altered pH gradient across their cell compartments. Nanoparticles responsive to the pH gradients are promising for cancer drug delivery. Such pH-responsive nanoparticles consist of a corona and a core, one or both of which respond to the external pH to change their soluble/insoluble or charge states. Nanoparticles whose coronas become positively charged or become soluble to make their targeting groups available for binding at the tumor extracellular pH have been developed for promoting cellular targeting and internalization. Nanoparticles whose cores become soluble or change their structures to release the carried drugs at the tumor extracellular pH or lysosomal pH have been developed for fast drug release into the extracellular fluid or cytosol. Such pH-responsive nanoparticles have therapeutic advantages over the conventional pH-insensitive counterparts.
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Affiliation(s)
- Youqing Shen
- Soft Materials Laboratory, Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, WY, USA
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40
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Gannot I, Ron I, Hekmat F, Chernomordik V, Gandjbakhche A. Functional optical detection based on pH dependent fluorescence lifetime. Lasers Surg Med 2005; 35:342-8. [PMID: 15611954 DOI: 10.1002/lsm.20101] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND AND OBJECTIVES Detection of possible alterations of physiological parameters (e.g., pH and temperature), resulting from malignant transformation of initially healthy tissue, can be a powerful diagnostic tool for earlier cancer detection. Such variations can be observed by comparing these parameters with those of healthy tissue surrounding the abnormality. Time-resolved spectroscopy of specifically targeted fluorescent labeled antibodies can be sensitive to such variations and provide a high resolution functional image of the region of interest. The goal of this study was to establish a forward experimental setup for calibration of the lifetime dependencies of near-IR fluorescent dyes on physiological parameters, and to develop analytical solutions, taking into account the effects of light propagation in turbid media (e.g., tissue), that was able to extract an original lifetime fluorescence signal from time-of-flight intensity distributions, measured in vivo from a deeply embedded live organ for further analysis. STUDY DESIGN/MATERIALS AND METHODS Tissue-like phantoms with embedded fluorescent dyes and background optical properties simulating those of live tissues were designed and created. Fluorescence decay curves were measured for different fluorophore positions, and pH values. Those measurements were made with a system based on a time-correlated single photon counting (TCSPC) instrument and a tunable femtosecond Ti-Sapphire system built by our group. RESULTS Decay curves were recorded for fluorophore depths of up to 5 mm and source-detector separation of 7 mm. It was shown that a forward model, based on the random walk theory, adequately described the experimental data. Measured pH dependencies of the fluorescence lifetime were characterized for two different dyes. CONCLUSIONS Good correlation between experimental data and predictions of the theoretical model allows the use of close-form analytical solutions to separate the effects of photon time delays due to multiple scattering in tissues from the original intensity fluorescence time decay curve, determined by the fluorophore itself and its immediate surroundings. It is the latter dependence that can be diagnostically important. Experimentally obtained scaling between lifetime and a parameter of interest can be used in vivo to obtain a map of physiological parameter changes which can serve as a base for an in vivo specific diagnostic system.
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Affiliation(s)
- Israel Gannot
- Lasers and Optics in Medicine Laboratory, Department of Biomedical Engineering, Faculty of Engineering Tel-Aviv University, Tel-Aviv 69978, Israel.
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41
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Gandjbakhche AH, Chernomordik V, Hattery D, Hassan M, Gannot I. Tissue characterization by quantitative optical imaging methods. Technol Cancer Res Treat 2004; 2:537-51. [PMID: 14640765 DOI: 10.1177/153303460300200606] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Optical methods have a long history in the field of medical diagnosis. The biomolecular specificity possible with optical methods has been particularly valuable in microscopy and histopathology while in vivo imaging of deep structures has traditionally been the domain of X-ray and MRI. The use of optical methods in deep tissue has been limited by multiple-scattering which blurs or distorts the optical signal. New stochastic methods which account for multiple scattering have been developed that are extending the usefulness of optical methods deep into tissue. In optical mammography, photons may travel through 10 cm of tissue before arriving at the detector. We have developed a method for quantifying parameters of anomalous sites in breast tissue that may be used for functional characterization of tumors. In other work presented here, we are developing fluorescence based methods to detect and monitor tumor status. The immune response to a tumor is a target for fluorescently labeled specific antibodies. We have developed a method to localize the tumor site using CW fluorescence. Additionally, we have developed a method which uses time-resolved data and capitalizes on probe lifetime sensitivity to metabolic parameters such as pH and temperature to obtain functional information from the tumor site.
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Affiliation(s)
- Amir H Gandjbakhche
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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42
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Patel AA, Gawlinski ET, Lemieux SK, Gatenby RA. A cellular automaton model of early tumor growth and invasion. J Theor Biol 2001; 213:315-31. [PMID: 11735284 DOI: 10.1006/jtbi.2001.2385] [Citation(s) in RCA: 192] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A hybrid cellular automaton model is described and used to simulate early tumor growth and examine the roles of host tissue vascular density and tumor metabolism in the ability of a small number of monoclonal transformed cells to develop into an invasive tumor. The model incorporates normal cells, tumor cells, necrotic or empty space, and a random network of native microvessels as components of a cellular automaton state vector. Diffusion of glucose and H(+)ions (the latter largely resulting from the tumor's excessive reliance on anaerobic metabolism) to and from the microvessels, and their utilization or production by cells, is modeled through the solution of differential equations. In this way, the cells and microvessels affect the extracellular concentrations of glucose and H(+)which, in turn, affect the evolution of the automaton. Simulations of the model demonstrate that: (i) high tumor H(+)ion production is favorable for tumor growth and invasion; however for every H(+)ion production rate, there exists a range of optimal microvessel densities (leading to a local pH favorable to tumor but not to normal cells) for which growth and invasion is most effective, (ii) at vascular densities below this range, both tumor and normal cells die due to excessively low pH, (iii) for vascular densities above the optimal range the microvessel network is highly efficient at removing acid and therefore the tumor cells lose their advantage over normal cells gained by high local H(+)concentration. While significant spatial gradients of glucose formed, no regions of detrimentally poor glucose perfusion (for either cell type) were observed, regardless of microvessel density. Depending on metabolic phenotype, a variety of tumor morphologies similar to those clinically observed were realized in the simulations. Lastly, a sharp transition (analogous to that of the adenoma-carcinoma sequence) between states of initial tumor confinement and efficient invasiveness was observed when H(+)production reached a critical value.
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Affiliation(s)
- A A Patel
- Department of Interventional Radiology, M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
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43
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Bosticardo M, Ariotti S, Losana G, Bernabei P, Forni G, Novelli F. Biased activation of human T lymphocytes due to low extracellular pH is antagonized by B7/CD28 costimulation. Eur J Immunol 2001; 31:2829-38. [PMID: 11536182 DOI: 10.1002/1521-4141(200109)31:9<2829::aid-immu2829>3.0.co;2-u] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
As T cell response to tumor-associated antigens may be impaired by the acidic microenvironment typical of solid tumors, we assessed the effect of extracellular pH (pH(e)) on the activation and proliferation of human T lymphocytes and generation of the cytotoxic response. T lymphocytes stimulated with anti-CD3 mAb or PHA at low pH(e) were unable to secrete IL-2 and IFN-gamma and their ability to progress through the cell cycle was impaired. T lymphocytes also displayed up-regulation of IFN-gammaR2 chain and CTLA-4 expression, rendering them sensitive to negative regulatory signals. Agonistic mAb against CD28, but not against CD2, completely restored cytokine production and cell cycle progression, but down-regulated IFN-gammaR2 and CTLA-4 expression. The anti-CD28mAb rescued the CTL response of allogeneic anti-tumor cultures generated at low pH(e). Following anti-CD28 mAb treatment, T cells synthesized cyclooxygenase-2 (Cox-2) protein, which is involved in the early phases of T cell activation. This rescue of T cell activation was independent of the inducible 6-phosphofructo-2-kinase (iPFK-2) pathway, which stimulates proliferation in hypoxic and acidic conditions. The restoration of proliferative and cytotoxic T cell responses by CD28-triggering provides insight into the mechanisms by which B7 enhances the T cell anti-tumor response in vivo.
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MESH Headings
- Abatacept
- Antibodies, Monoclonal/immunology
- Antigens, CD/metabolism
- Antigens, Differentiation/metabolism
- Antigens, Differentiation, B-Lymphocyte/metabolism
- B7-1 Antigen/metabolism
- CD28 Antigens/immunology
- CD28 Antigens/metabolism
- CTLA-4 Antigen
- Cells, Cultured
- Cyclooxygenase 2
- Cytokines/biosynthesis
- Extracellular Space/chemistry
- Humans
- Hydrogen-Ion Concentration
- Immunoconjugates
- Isoenzymes/biosynthesis
- Lymphocyte Activation
- Membrane Proteins
- Neoplasms, Experimental/immunology
- Prostaglandin-Endoperoxide Synthases/biosynthesis
- Receptors, Interferon/metabolism
- Receptors, Interleukin-2/metabolism
- Receptors, Transferrin
- T-Lymphocytes/immunology
- T-Lymphocytes, Cytotoxic/immunology
- Tumor Cells, Cultured
- Interferon gamma Receptor
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Affiliation(s)
- M Bosticardo
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Italy
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44
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Shi Q, Le X, Wang B, Abbruzzese JL, Xiong Q, He Y, Xie K. Regulation of vascular endothelial growth factor expression by acidosis in human cancer cells. Oncogene 2001; 20:3751-6. [PMID: 11439338 DOI: 10.1038/sj.onc.1204500] [Citation(s) in RCA: 182] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2000] [Revised: 03/22/2001] [Accepted: 04/02/2001] [Indexed: 12/17/2022]
Abstract
The influence of acidosis on the expression of the vascular endothelial growth factor (VEGF) gene was determined. FG human pancreatic adenocarcinoma cells were incubated for various time periods in media at a physiologically relevant pH level (6.7-7.4). The expression of VEGF mRNA and protein secretion was inversely correlated with pH in a pH- and time-dependent manner. Transient acidosis also activated the VEGF promoter/enhancer luciferase reporter, which was consistent with an increased VEGF gene transcription rate and VEGF mRNA half-life. These data indicated that acidosis transcriptionally and posttranscriptionally regulates VEGF expression, suggesting that an acidic tumor microenvironment contributes to tumor angiogenesis and progression.
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Affiliation(s)
- Q Shi
- Department of Gastrointestinal Medical Oncology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas, TX 77030, USA
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45
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García-Cañero R, Trilla C, Pérez de Diego J, Díaz-Gil JJ, Cobo JM. Na+ :H+ exchange inhibition induces intracellular acidosis and differentially impairs cell growth and viability of human and rat hepatocarcinoma cells. Toxicol Lett 1999; 106:215-28. [PMID: 10403666 DOI: 10.1016/s0378-4274(99)00072-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Amiloride and its more potent analog, hexamethylene amiloride (HMA), inhibits Na+ :H+ exchange and decreases intracellular pH in a concentration-dependent way in two human hepatocarcinoma cell lines and in a rat hepatocarcinoma cell line that differs in its phenotypic characteristics, resembling the clinical situation encountered in human hepatocarcinomas. After 24 h of exposure, DNA synthesis and cell protein content of the cultures decreases according to the concentration of the drugs and in parallel to Na+ exchange inhibition and the drop in pHi promoted. RNA and protein syntheses are less sensitive to its action. The above effects induced by HMA are accompanied by an abrupt decrease in cell viability and lysosomal integrity at 24 h. These effects develop gradually with the exposure time as does the increase in free radical production. Decreased viability is totally or partially restored by N-acetylcysteine or deferoxamine, but the degree of intracellular acidification produced is not. These results tend to suggest that intracellular acidification can diminish cell growth and provoke cytotoxic cell death by diminishing reduced glutathione (GSH) levels and impairing lysosomal integrity, reflecting the sensitivity of hepatocarcinoma cells to Na+ exchange inhibition and intracellular acidosis.
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Affiliation(s)
- R García-Cañero
- Experimental Hepatology Laboratory, Experimental Biochemistry Service, Clínica Puerta de Hierro, Madrid, Spain.
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46
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Abstract
Although limited data exist, electrode-measured pH values of human tumors and adjacent normal tissues, which are concurrently obtained by the same investigator in the same patient, consistently show that the electrode pH (believed to represent tissue extracellular pH primarily) is substantially and consistently lower in tumor than in normal tissue. In contrast, the 31P-magnetic resonance spectroscopy-estimated intracellular pH is essentially identical or slightly more basic in tumor compared with normal tissue. As a consequence, the cellular pH gradient is substantially reduced or reversed in these tissues. This difference provides an exploitable avenue for the treatment of cancer. The extent to which drugs exhibiting weakly acid or basic properties are ionized depends on their ionization potential (pKa) and the pH of their milieu. Weakly acidic drugs that are lipid soluble in their nonionized state diffuse freely across the cell membrane and on entering a relatively basic intracellular compartment become trapped and accumulate within the cell. This may lead to substantial (10-fold or more) differences in the intracellular-to-extracellular drug distribution between tumor and normal tissue for cytotoxics, hypoxic cell sensitizers, or other drugs exhibiting appropriate pKa. Experimental in vitro evaluation of these predictions confirms both the predicted pH gradient-dependent changes in cellular drug accumulation and toxicity.
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Affiliation(s)
- L E Gerweck
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02192, USA
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47
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Yamagata M, Hasuda K, Stamato T, Tannock IF. The contribution of lactic acid to acidification of tumours: studies of variant cells lacking lactate dehydrogenase. Br J Cancer 1998; 77:1726-31. [PMID: 9667639 PMCID: PMC2150353 DOI: 10.1038/bjc.1998.289] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Solid tumours develop an acidic extracellular environment with high concentration of lactic acid, and lactic acid produced by glycolysis has been assumed to be the major cause of tumour acidity. Experiments using lactate dehydrogenase (LDH)-deficient ras-transfected Chinese hamster ovarian cells have been undertaken to address directly the hypothesis that lactic acid production is responsible for tumour acidification. The variant cells produce negligible quantities of lactic acid and consume minimal amounts of glucose compared with parental cells. Lactate-producing parental cells acidified lightly-buffered medium but variant cells did not. Tumours derived from parental and variant cells implanted into nude mice were found to have mean values of extracellular pH (pHe) of 7.03 +/- 0.03 and 7.03 +/- 0.05, respectively, both of which were significantly lower than that of normal muscle (pHe = 7.43 +/- 0.03; P < 0.001). Lactic acid concentration in variant tumours (450 +/- 90 microg g(-1) wet weight) was much lower than that in parental tumours (1880 +/- 140 microg/g(-1)) and similar to that in serum (400 +/- 35 microg/g(-1)). These data show discordance between mean levels of pHe and lactate content in tumours; the results support those of Newell et al (1993) and suggest that the production of lactic acid via glycolysis causes acidification of culture medium, but is not the only mechanism, and is probably not the major mechanism responsible for the development of an acidic environment within solid tumours.
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Affiliation(s)
- M Yamagata
- Department of Medicine and Medical Biophysics, Ontario Cancer Institute/Princess Margaret Hospital, Toronto, Canada
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48
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Lewis MR, Shively JE. Maleimidocysteineamido-DOTA derivatives: new reagents for radiometal chelate conjugation to antibody sulfhydryl groups undergo pH-dependent cleavage reactions. Bioconjug Chem 1998; 9:72-86. [PMID: 9460549 DOI: 10.1021/bc970136v] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We have synthesized two bifunctional derivatives of the macrocyclic chelating agent 1,4,7,10-tetraazacyclododecane-N,N',N",N"-tetraacetic acid (DOTA) equipped with maleimide groups for conjugation to reduced disulfide bonds of monoclonal antibodies. Using water-soluble carbodiimide chemistry, DOTA was coupled to L-cysteine to incorporate both a "pendant-type" carboxyl group for metal coordination and an orthogonal thiol group for protein attachment. The homobifunctional reagent 1,6-bis(maleimido)hexane was then used to introduce the maleimide functionality via a sulfide linkage to the macrocycle, and alternatively, the sulfide group was converted to a sulfone side chain. Both maleimide derivatives were conjugated to the anticarcinoembryonic antigen chimeric monoclonal antibody cT84.66 after light reduction of the mAb with dithiothreitol. In this manner, antibody conjugates were prepared which afforded near-quantitative labeling with the radiometals 111In(III) and 90Y(III) as well as quantitative immunoreactivity. Radioimmunoconjugates prepared with the sulfide and sulfone compounds exhibited relatively rapid linker-dependent radiometal loss when incubated in human serum and aqueous solutions at physiological temperature and pH. The unconjugated maleimidocysteineamido-DOTA derivatives and their Y(III) complexes were incubated in aqueous solution at 37 degrees C, and the resulting decomposition products were analyzed by HPLC and mass spectrometry. These studies revealed that the two bifunctional chelating agents underwent linker-specific cleavage reactions which were considerably faster at pH 7.4 than at pH 5.4. The chemically labile linker systems are expected to release chelated radiometal from mAb conjugates in a pH-dependent manner. This property may impart favorable tumor uptake and normal tissue clearance on radioimmunoconjugates prepared with these reagents, on the basis of the observation that many solid tumors are significantly more acidic than normal tissues.
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Affiliation(s)
- M R Lewis
- City of Hope Graduate Program in Biological Sciences, Duarte, California 91010, USA
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49
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Skøyum R, Eide K, Berg K, Rofstad EK. Energy metabolism in human melanoma cells under hypoxic and acidic conditions in vitro. Br J Cancer 1997; 76:421-8. [PMID: 9275017 PMCID: PMC2227985 DOI: 10.1038/bjc.1997.405] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The response to treatment and the malignant progression of tumours are influenced by the ability of the tumour cells to withstand severe energy deprivation during prolonged exposure to hypoxia at normal or low extracellular pH (pHe). The objective of the present work was to demonstrate intertumour heterogeneity under conditions of microenvironment-induced energy deprivation and to investigate whether the heterogeneity can be attributed to differences in the capacity of the tumour cells to generate energy in an oxygen-deficient microenvironment. Cultures of four human melanoma cell lines (BEX-c, COX-c, SAX-c, WIX-c) were exposed to hypoxia in vitro at pHe 7.4, 7.0 or 6.6 for times up to 31 h by using the steel-chamber method. High-performance liquid chromatography was used to assess adenylate energy charge as a function of exposure time. Cellular rates of glucose uptake and lactate release were determined by using standard enzymatic test kits. The adenylate energy charge decreased with time under hypoxia in all cell lines. The decrease was most pronounced shortly after the treatment had been initiated and then tapered off. BEX-c and SAX-c showed a significantly higher adenylate energy charge under hypoxic conditions than did COX-c and WIX-c whether the pHe was 7.4, 7.0 or 6.6, showing that tumours can differ in the ability to avoid energy deprivation during microenvironmental stress. There was no correlation between the adenylate energy charge and the rates of glucose uptake and lactate release. Intertumour heterogeneity in the ability to withstand energy deprivation in an oxygen-deficient microenvironment cannot therefore be attributed mainly to differences in the capacity of the tumour cells to generate energy by anaerobic metabolism. The data presented here suggest that the heterogeneity is rather caused by differences in the capacity of the tumour cells to reduce the rate of energy consumption when exposed to hypoxia.
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Affiliation(s)
- R Skøyum
- Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, Oslo, Norway
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50
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Dellian M, Helmlinger G, Yuan F, Jain RK. Fluorescence ratio imaging of interstitial pH in solid tumours: effect of glucose on spatial and temporal gradients. Br J Cancer 1996; 74:1206-15. [PMID: 8883406 PMCID: PMC2075944 DOI: 10.1038/bjc.1996.518] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Tumour pH plays a significant role in cancer treatment. However, because of the limitations of the current measurement techniques, spatially and temporally resolved pH data, obtained non-invasively in solid tumours, are not available. Fluorescence ratio imaging microscopy (FRIM) has been used previously for noninvasive, dynamic evaluation of pH in neoplastic tissue in vivo (Martin GR, Jain RK 1994, Cancer Res., 54, 5670-5674). However, owing to problems associated with quantitative fluorescence in thick biological tissues, these studies were limited to thin (50 microns) tumours. We, therefore, adapted the FRIM technique for pH determination in thick (approximately 2 mm) solid tumours in vivo using a pinhole illumination-optical sectioning (PIOS) method. Results show that (1) steep interstitial pH gradients (5 microns resolution), with different spatial patterns, exist between tumour blood vessels; (2) pH decreased by an average of 0.10 pH units over a distance of 40 microns away from the blood vessel wall, and by 0.33 pH units over a 70 microns distance; (3) the maximum pH drop, defined as the pH difference between the intervessel midpoint and the vessel wall, was positively correlated with the intervessel distance; (4) 45 min following a systemic glucose injection (6 g kg-1 i.v), interstitial pH gradients were shifted to lower pH values by an average of 0.15 pH units, while the spatial gradient (slope) was maintained, when compared with preglucose values. This pH decrease was not accompanied by significant changes in local blood flow. pH gradients returned to near-baseline values 90 min after glucose injection; (5) interstitial tumour pH before hyperglycaemia and the glucose-induced pH drop strongly depended on the local vessel density; and (6) sodium bicarbonate treatment, either acute (1 M, 0.119 ml h-1 for 3 h i.v.) or chronic (1% in drinking water for 8 days), did not significantly change interstitial tumour pH. Modified FRIM may be combined with other optical methods (e.g. phosphorescence quenching) to evaluate non-invasively the spatial and temporal characteristics of extracellular pH, intracellular pH and pO2 in solid tumours. This will offer unique information about tumour metabolism and its modification by treatment modalities used in different cancer therapies.
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Affiliation(s)
- M Dellian
- Edwin L Steele Laboratory, Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA
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