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Hasnat S, Metsäniitty M, Nurmi K, Eklund KK, Salem A. Intracellular bacterial LPS drives pyroptosis and promotes aggressive phenotype in oral squamous cell carcinoma. Med Oncol 2025; 42:205. [PMID: 40338411 PMCID: PMC12062154 DOI: 10.1007/s12032-025-02766-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2025] [Accepted: 04/28/2025] [Indexed: 05/09/2025]
Abstract
Intracellular bacterial components represent an emerging tumor element that has recently been documented in multiple cancer types, yet their biological functions remain poorly understood. Oral squamous cell carcinoma (OSCC) is a particularly aggressive malignancy lacking highly effective targeted treatments. Here, we explored the functional significance of intracellular bacterial lipopolysaccharide (LPS) in OSCC. Normal human oral keratinocytes (HOKs), HPV-transformed oral keratinocytes (IHGK), and three OSCC cell lines were transfected with ultrapure bacterial LPS. Cytotoxicity was assessed via lactate dehydrogenase (LDH) release assays. Production of interleukin (IL)-1β and IL-18 was measured using ELISA. Impact on tumor progression was evaluated using cell proliferation, migration, invasion, and tubulogenesis assays. Intracellular LPS-induced significant LDH release and increased secretion of IL-18 and IL-1β in IHGK and cancer cells, but not in normal HOKs, indicating selective cytotoxicity and pyroptosis. Notably, metastatic cancer cells exhibited enhanced invasive and vessel-like structures upon LPS exposure, while IHGK cells exhibited increased proliferation without changes in migration. Our findings suggest that intracellular LPS may not merely reside passively within the tumor milieu, but could contribute to OSCC progression by triggering noncanonical inflammasome activation and pyroptosis. This process may enhance pro-inflammatory signaling and more aggressive cellular phenotypes, especially in metastatic settings. Targeting intracellular LPS or its downstream inflammasome pathways may thus represent a promising therapeutic strategy for OSCC, warranting further in vivo and clinical investigations.
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Affiliation(s)
- Shrabon Hasnat
- Department of Oral and Maxillofacial Diseases, Clinicum, Faculty of Medicine, University of Helsinki, 00014, Helsinki, Finland
| | - Marjut Metsäniitty
- Department of Oral and Maxillofacial Diseases, Clinicum, Faculty of Medicine, University of Helsinki, 00014, Helsinki, Finland
| | - Katariina Nurmi
- Translational Immunology Research Program (TRIMM), Research Program Unit (RPU), University of Helsinki, 00014, Helsinki, Finland
| | - Kari K Eklund
- Translational Immunology Research Program (TRIMM), Research Program Unit (RPU), University of Helsinki, 00014, Helsinki, Finland
- Department of Rheumatology, University of Helsinki and Helsinki University Hospital, 00014, Helsinki, Finland
| | - Abdelhakim Salem
- Department of Oral and Maxillofacial Diseases, Clinicum, Faculty of Medicine, University of Helsinki, 00014, Helsinki, Finland.
- Translational Immunology Research Program (TRIMM), Research Program Unit (RPU), University of Helsinki, 00014, Helsinki, Finland.
- Head and Neck Oncobiome Group, Department of Oral and Maxillofacial Diseases, Clinicum, Faculty of Medicine, University of Helsinki, 00014, Helsinki, Finland.
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Metsäniitty M, Hasnat S, Öhman C, Salo T, Eklund KK, Oscarsson J, Salem A. Zebrafish larvae as a model for studying the impact of oral bacterial vesicles on tumor cell growth and metastasis. Hum Cell 2024; 37:1696-1705. [PMID: 39138804 PMCID: PMC11481661 DOI: 10.1007/s13577-024-01114-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 07/29/2024] [Indexed: 08/15/2024]
Abstract
Oral bacteria naturally secrete extracellular vesicles (EVs), which have attracted attention for their promising biomedical applications including cancer therapeutics. However, our understanding of EV impact on tumor progression is hampered by limited in vivo models. In this study, we propose a facile in vivo platform for assessing the effect of EVs isolated from different bacterial strains on oral cancer growth and dissemination using the larval zebrafish model. EVs were isolated from: wild-type Aggregatibacter actinomycetemcomitans and its mutant strains lacking the cytolethal distending toxin (CDT) or lipopolysaccharide (LPS) O-antigen; and wild-type Porphyromonas gingivalis. Cancer cells pretreated with EVs were xenotransplanted into zebrafish larvae, wherein tumor growth and metastasis were screened. We further assessed the preferential sites for the metastatic foci development. Interestingly, EVs from the CDT-lacking A. actinomycetemcomitans resulted in an increased tumor growth, whereas EVs lacking the lipopolysaccharide O-antigen reduced the metastasis rate. P. gingivalis-derived EVs showed no significant effects. Cancer cells pretreated with EVs from the mutant A. actinomycetemcomitans strains tended to metastasize less often to the head and tail compared to the controls. In sum, the proposed approach provided cost- and labor-effective yet efficient model for studying bacterial EVs in oral carcinogenesis, which can be easily extended for other cancer types. Furthermore, our results support the notion that these nanosized particles may represent promising targets in cancer therapeutics.
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Affiliation(s)
- Marjut Metsäniitty
- Department of Oral and Maxillofacial Diseases, Clinicum, University of Helsinki, 00014, Helsinki, Finland
| | - Saika Hasnat
- Department of Oral and Maxillofacial Diseases, Clinicum, University of Helsinki, 00014, Helsinki, Finland
| | - Carina Öhman
- Oral Microbiology, Department of Odontology, Umeå University, 90187, Umeå, Sweden
| | - Tuula Salo
- Department of Oral and Maxillofacial Diseases, Clinicum, University of Helsinki, 00014, Helsinki, Finland
| | - Kari K Eklund
- Department of Rheumatology, University of Helsinki and Helsinki University Hospital, 00014, Helsinki, Finland
- Translational Immunology Research Program (TRIMM), Research Program Unit (RPU), University of Helsinki, 00014, Helsinki, Finland
| | - Jan Oscarsson
- Oral Microbiology, Department of Odontology, Umeå University, 90187, Umeå, Sweden
| | - Abdelhakim Salem
- Department of Oral and Maxillofacial Diseases, Clinicum, University of Helsinki, 00014, Helsinki, Finland.
- Translational Immunology Research Program (TRIMM), Research Program Unit (RPU), University of Helsinki, 00014, Helsinki, Finland.
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Metsäniitty M, Hasnat S, Öhman C, Salo T, Eklund KK, Oscarsson J, Salem A. Extracellular vesicles from Aggregatibacter actinomycetemcomitans exhibit potential antitumorigenic effects in oral cancer: a comparative in vitro study. Arch Microbiol 2024; 206:244. [PMID: 38702412 PMCID: PMC11068833 DOI: 10.1007/s00203-024-03976-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 04/24/2024] [Indexed: 05/06/2024]
Abstract
Aggregatibacter actinomycetemcomitans is an opportunistic Gram-negative periodontopathogen strongly associated with periodontitis and infective endocarditis. Recent evidence suggests that periodontopathogens can influence the initiation and progression of oral squamous cell carcinoma (OSCC). Herein we aimed to investigate the effect of A. actinomycetemcomitans-derived extracellular vesicles (EVs) on OSCC cell behavior compared with EVs from periodontopathogens known to associate with carcinogenesis. EVs were isolated from: A. actinomycetemcomitans and its mutant strains lacking the cytolethal distending toxin (CDT) or lipopolysaccharide (LPS) O-antigen; Porphyromonas gingivalis; Fusobacterium nucleatum; and Parvimonas micra. The effect of EVs on primary and metastatic OSCC cells was assessed using cell proliferation, apoptosis, migration, invasion, and tubulogenesis assays. A. actinomycetemcomitans-derived EVs reduced the metastatic cancer cell proliferation, invasion, tubulogenesis, and increased apoptosis, mostly in CDT- and LPS O-antigen-dependent manner. EVs from F. nucleatum impaired the metastatic cancer cell proliferation and induced the apoptosis rates in all OSCC cell lines. EVs enhanced cancer cell migration regardless of bacterial species. In sum, this is the first study demonstrating the influence of A. actinomycetemcomitans-derived EVs on oral cancer in comparison with other periodontopathogens. Our findings revealed a potential antitumorigenic effect of these EVs on metastatic OSCC cells, which warrants further in vivo investigations.
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Affiliation(s)
- Marjut Metsäniitty
- Department of Oral and Maxillofacial Diseases, Clinicum, Faculty of Medicine, University of Helsinki, Helsinki, 00014, Finland
| | - Shrabon Hasnat
- Department of Oral and Maxillofacial Diseases, Clinicum, Faculty of Medicine, University of Helsinki, Helsinki, 00014, Finland
| | - Carina Öhman
- Oral Microbiology, Department of Odontology, Umeå University, Umeå, 90187, Sweden
| | - Tuula Salo
- Department of Oral and Maxillofacial Diseases, Clinicum, Faculty of Medicine, University of Helsinki, Helsinki, 00014, Finland
| | - Kari K Eklund
- Department of Rheumatology, University of Helsinki and Helsinki University Hospital, Helsinki, 00014, Finland
- Translational Immunology Research Program (TRIMM), Research Program Unit (RPU), Faculty of Medicine, University of Helsinki, Helsinki, 00014, Finland
| | - Jan Oscarsson
- Oral Microbiology, Department of Odontology, Umeå University, Umeå, 90187, Sweden
| | - Abdelhakim Salem
- Department of Oral and Maxillofacial Diseases, Clinicum, Faculty of Medicine, University of Helsinki, Helsinki, 00014, Finland.
- Translational Immunology Research Program (TRIMM), Research Program Unit (RPU), Faculty of Medicine, University of Helsinki, Helsinki, 00014, Finland.
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Dorna D, Paluszczak J. Targeting cancer stem cells as a strategy for reducing chemotherapy resistance in head and neck cancers. J Cancer Res Clin Oncol 2023; 149:13417-13435. [PMID: 37453969 PMCID: PMC10587253 DOI: 10.1007/s00432-023-05136-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/05/2023] [Indexed: 07/18/2023]
Abstract
PURPOSE Resistance to chemotherapy and radiotherapy is the primary cause of a poor prognosis in oncological patients. Researchers identified many possible mechanisms involved in gaining a therapy-resistant phenotype by cancer cells, including alterations in intracellular drug accumulation, detoxification, and enhanced DNA damage repair. All these features are characteristic of stem cells, making them the major culprit of chemoresistance. This paper reviews the most recent evidence regarding the association between the stemness phenotype and chemoresistance in head and neck cancers. It also investigates the impact of pharmacologically targeting cancer stem cell populations in this subset of malignancies. METHODS This narrative review was prepared based on the search of the PubMed database for relevant papers. RESULTS Head and neck cancer cells belonging to the stem cell population are distinguished by the high expression of certain surface proteins (e.g., CD10, CD44, CD133), pluripotency-related transcription factors (SOX2, OCT4, NANOG), and increased activity of aldehyde dehydrogenase (ALDH). Chemotherapy itself increases the percentage of stem-like cells. Importantly, the intratumor heterogeneity of stem cell subpopulations reflects cell plasticity which has great importance for chemoresistance induction. CONCLUSIONS Evidence points to the advantage of combining classical chemotherapeutics with stemness modulators thanks to the joint targeting of the bulk of proliferating tumor cells and chemoresistant cancer stem cells, which could cause recurrence.
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Affiliation(s)
- Dawid Dorna
- Department of Pharmaceutical Biochemistry, Poznan University of Medical Sciences, Ul. Święcickiego 4, 60-781 Poznan, Poland
| | - Jarosław Paluszczak
- Department of Pharmaceutical Biochemistry, Poznan University of Medical Sciences, Ul. Święcickiego 4, 60-781 Poznan, Poland
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Kummer S, Klang A, Strohmayer C, Walter I, Jindra C, Kneissl S, Brandt S. Feline SCCs of the Head and Neck Display Partial Epithelial-Mesenchymal Transition and Harbor Stem Cell-like Cancer Cells. Pathogens 2023; 12:1288. [PMID: 38003753 PMCID: PMC10674711 DOI: 10.3390/pathogens12111288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 11/26/2023] Open
Abstract
Squamous cell carcinoma of the head and neck (HNSCC) is a malignant cancer disease in humans and animals. There is ample evidence that the high plasticity of cancer cells, i.e., their ability to switch from an epithelial to a mesenchymal, endothelial, and stem cell-like phenotype, chiefly contributes to progression, metastasis, and multidrug resistance of human HNSCCs. In feline HNSCC, the field of cancer cell plasticity is still unexplored. In this study, fourteen feline HNSCCs with a known feline papillomavirus (FPV) infection status were subjected to histopathological grading and subsequent screening for expression of epithelial, mesenchymal, and stem cell markers by immunohistochemistry (IHC) and immunofluorescence staining (IF). Irrespective of the FPV infection status, all tumors except one corresponded to high-grade, invasive lesions and concurrently expressed epithelial (keratins, E-cadherin, β-catenin) and mesenchymal (vimentin, N-cadherin, CD146) proteins. This finding is indicative for partial epithelial-mesenchymal transition (pEMT) events in the lesions, as similarly described for human HNSCCs. IF double staining revealed the presence of CD44/CD271 double-positive cells notably within the tumors' invasive fronts that likely correspond to cancer stem cells. Taken together, the obtained findings suggest that feline HNSCCs closely resemble their human counterparts with respect to tumor cell plasticity.
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Affiliation(s)
- Stefan Kummer
- VetCore Facility for Research, University of Veterinary Medicine, 1210 Vienna, Austria; (S.K.); (I.W.)
| | - Andrea Klang
- Institute of Pathology, Department of Pathobiology, University of Veterinary Medicine, 1210 Vienna, Austria;
| | - Carina Strohmayer
- Clinical Unit of Diagnostic Imaging, Department for Companion Animals and Horses, University of Veterinary Medicine, 1210 Vienna, Austria; (C.S.); (S.K.)
| | - Ingrid Walter
- VetCore Facility for Research, University of Veterinary Medicine, 1210 Vienna, Austria; (S.K.); (I.W.)
- Institute of Morphology, Department of Pathobiology, University of Veterinary Medicine, 1210 Vienna, Austria
| | - Christoph Jindra
- Research Group Oncology (RGO), Clinical Unit of Equine Surgery, Department for Companion Animals and Horses, University of Veterinary Medicine, 1210 Vienna, Austria;
- Division of Molecular Oncology and Hematology, Karl Landsteiner University of Health Sciences, 3500 Krems an der Donau, Austria
| | - Sibylle Kneissl
- Clinical Unit of Diagnostic Imaging, Department for Companion Animals and Horses, University of Veterinary Medicine, 1210 Vienna, Austria; (C.S.); (S.K.)
| | - Sabine Brandt
- Research Group Oncology (RGO), Clinical Unit of Equine Surgery, Department for Companion Animals and Horses, University of Veterinary Medicine, 1210 Vienna, Austria;
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