1
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Chen H, Wei J, Zhu Z, Hou Y. Multifaceted roles of PD-1 in tumorigenesis: From immune checkpoint to tumor cell-intrinsic function. Mol Carcinog 2024; 63:1436-1448. [PMID: 38751009 DOI: 10.1002/mc.23740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/27/2024] [Accepted: 05/04/2024] [Indexed: 07/10/2024]
Abstract
Programmed cell death 1 (PD-1), a key immune checkpoint receptor, has been extensively studied for its role in regulating immune responses in cancer. However, recent research has unveiled a complex and dual role for PD-1 in tumorigenesis. While PD-1 is traditionally associated with immune cells, this article explores its expression in various cancer cells and its impact on cancer progression. PD-1's functions extend beyond immune regulation, as it has been found to both promote and suppress tumor growth, depending on the cancer type. These findings have significant implications for the future of cancer treatment and our understanding of the immune response in the context of cancer. This article calls for further research into the multifaceted roles of PD-1 to optimize its therapeutic potential and improve patient outcomes in the fight against cancer.
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Affiliation(s)
- Huiqing Chen
- School of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Jiayu Wei
- School of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Zhen Zhu
- Zhenjiang Stomatological Hospital, Zhenjiang, China
| | - Yongzhong Hou
- School of Life Sciences, Jiangsu University, Zhenjiang, China
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2
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Dahlquist KJV, Huggins MA, Yousefzadeh MJ, Soto-Palma C, Cholensky SH, Pierson M, Smith DM, Hamilton SE, Camell CD. PD1 blockade improves survival and CD8 + cytotoxic capacity, without increasing inflammation, during normal microbial experience in old mice. NATURE AGING 2024; 4:915-925. [PMID: 38689133 DOI: 10.1038/s43587-024-00620-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 03/29/2024] [Indexed: 05/02/2024]
Abstract
By 2030, individuals 65 years of age or older will make up approximately 20% of the world's population1. Older individuals are at the highest risk for mortality from infections, largely due to the pro-inflammatory, dysfunctional immune response, which is collectively known as immunosenescence2. During aging, CD8+ T cells acquire an exhausted phenotype, including increased expression of inhibitory receptors, such as programmed cell death 1 (PD1), a decline in effector function and elevated expression of inflammatory factors3-7. PD1 reduces T cell receptor activity via SHP2-dependent dephosphorylation of multiple pathways; accordingly, inhibiting PD1 activity through monoclonal antibodies increases CD8+ T cell effector response in young mice8-11. Attempts to improve CD8+ T cell responses by blocking inhibitory receptors are attractive; however, they can lead to adverse immune events due to overamplification of T cell receptor signaling and T cell activation12,13. Here we investigated the effect of monoclonal anti-PD1 immunotherapy during normal microbial experience, otherwise known as exposure to dirty mice, to determine whether it either improves exhausted CD8+ T cell responses in old mice or leads to a heightened inflammatory response and increased mortality.
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Affiliation(s)
- Korbyn J V Dahlquist
- Biochemistry, Molecular Biology and Biophysics Graduate Program, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
- Department of Biochemistry, Molecular Biology and Biophysics, Institute on the Biology of Aging and Metabolism, University of Minnesota, Minneapolis, MN, USA
- Center for Immunology, University of Minnesota, Minneapolis, MN, USA
| | - Matthew A Huggins
- Center for Immunology, University of Minnesota, Minneapolis, MN, USA
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| | - Matthew J Yousefzadeh
- Department of Biochemistry, Molecular Biology and Biophysics, Institute on the Biology of Aging and Metabolism, University of Minnesota, Minneapolis, MN, USA
- Department of Medicine, Columbia Center for Translational Immunology, Columbia Center for Healthy Longevity, Columbia University, New York, NY, USA
| | - Carolina Soto-Palma
- Department of Biochemistry, Molecular Biology and Biophysics, Institute on the Biology of Aging and Metabolism, University of Minnesota, Minneapolis, MN, USA
| | - Stephanie H Cholensky
- Department of Biochemistry, Molecular Biology and Biophysics, Institute on the Biology of Aging and Metabolism, University of Minnesota, Minneapolis, MN, USA
| | - Mark Pierson
- Center for Immunology, University of Minnesota, Minneapolis, MN, USA
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| | - Declan M Smith
- Department of Biochemistry, Molecular Biology and Biophysics, Institute on the Biology of Aging and Metabolism, University of Minnesota, Minneapolis, MN, USA
| | - Sara E Hamilton
- Department of Biochemistry, Molecular Biology and Biophysics, Institute on the Biology of Aging and Metabolism, University of Minnesota, Minneapolis, MN, USA
- Center for Immunology, University of Minnesota, Minneapolis, MN, USA
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| | - Christina D Camell
- Biochemistry, Molecular Biology and Biophysics Graduate Program, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.
- Department of Biochemistry, Molecular Biology and Biophysics, Institute on the Biology of Aging and Metabolism, University of Minnesota, Minneapolis, MN, USA.
- Center for Immunology, University of Minnesota, Minneapolis, MN, USA.
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3
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Zhivaki D, Kennedy SN, Park J, Boriello F, Devant P, Cao A, Bahleda KM, Murphy S, McCabe C, Evavold CL, Chapman KL, Zanoni I, Ashenberg O, Xavier RJ, Kagan JC. Correction of age-associated defects in dendritic cells enables CD4 + T cells to eradicate tumors. Cell 2024:S0092-8674(24)00535-X. [PMID: 38870946 DOI: 10.1016/j.cell.2024.05.026] [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: 11/02/2022] [Revised: 04/02/2024] [Accepted: 05/13/2024] [Indexed: 06/15/2024]
Abstract
Defective host defenses later in life are associated with changes in immune cell activities, suggesting that age-specific considerations are needed in immunotherapy approaches. In this study, we found that PD-1 and CTLA4-based cancer immunotherapies are unable to eradicate tumors in elderly mice. This defect in anti-tumor activity correlated with two known age-associated immune defects: diminished abundance of systemic naive CD8+ T cells and weak migratory activities of dendritic cells (DCs). We identified a vaccine adjuvant, referred to as a DC hyperactivator, which corrects DC migratory defects in the elderly. Vaccines containing tumor antigens and DC hyperactivators induced T helper type 1 (TH1) CD4+ T cells with cytolytic activity that drive anti-tumor immunity in elderly mice. When administered early in life, DC hyperactivators were the only adjuvant identified that elicited anti-tumor CD4+ T cells that persisted into old age. These results raise the possibility of correcting age-associated immune defects through DC manipulation.
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Affiliation(s)
- Dania Zhivaki
- Harvard Medical School and Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Stephanie N Kennedy
- Harvard Medical School and Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Josh Park
- Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Francesco Boriello
- Harvard Medical School and Division of Immunology, Boston Children's Hospital, Boston, MA, USA
| | - Pascal Devant
- Harvard Medical School and Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Anh Cao
- Harvard Medical School and Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Kristin M Bahleda
- Harvard Medical School and Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Shane Murphy
- Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Cristin McCabe
- Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Charles L Evavold
- Harvard Medical School and Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Kate L Chapman
- Harvard Medical School and Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Ivan Zanoni
- Harvard Medical School and Division of Immunology, Boston Children's Hospital, Boston, MA, USA
| | - Orr Ashenberg
- Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Ramnik J Xavier
- Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Jonathan C Kagan
- Harvard Medical School and Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA.
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4
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Cho T, Wierk A, Gertsenstein M, Rodgers CE, Uetrecht J, Henderson JT. The development and characterization of a CRISPR/Cas9-mediated PD-1 functional knockout rat as a tool to study idiosyncratic drug reactions. Toxicol Sci 2024; 198:233-245. [PMID: 38230816 DOI: 10.1093/toxsci/kfae003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024] Open
Abstract
Idiosyncratic drug reactions are rare but serious adverse drug reactions unrelated to the known therapeutic properties of the drug and manifest in only a small percentage of the treated population. Animal models play an important role in advancing mechanistic studies examining idiosyncratic drug reactions. However, to be useful, they must possess similarities to those seen clinically. Although mice currently represent the dominant mammalian genetic model, rats are advantageous in many areas of pharmacologic study where their physiology can be examined in greater detail and is more akin to that seen in humans. In the area of immunology, this includes autoimmune responses and susceptibility to diabetes, in which rats more accurately mimic disease states in humans compared with mice. For example, oral nevirapine treatment can induce an immune-mediated skin rash in humans and rats, but not in mice due to the absence of the sulfotransferase required to form reactive metabolites of nevirapine within the skin. Using CRISPR-mediated gene editing, we developed a modified line of transgenic rats in which a segment of IgG-like ectodomain containing the core PD-1 interaction motif containing the native ligand and therapeutic antibody domain in exon 2 was deleted. Removal of this region critical for mediating PD-1/PD-L1 interactions resulted in animals with an increased immune response resulting in liver injury when treated with amodiaquine.
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Affiliation(s)
- Tiffany Cho
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Antonia Wierk
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Marina Gertsenstein
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Christopher E Rodgers
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Jack Uetrecht
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Jeffrey T Henderson
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
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5
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Martins C, Rasbach E, Heppt MV, Singh P, Kulcsar Z, Holzgruber J, Chakraborty A, Mucciarone K, Kleffel S, Brandenburg A, Hoetzenecker W, Rahbari NN, DeCaprio JA, Thakuria M, Murphy GF, Ramsey MR, Posch C, Barthel SR, Schatton T. Tumor cell-intrinsic PD-1 promotes Merkel cell carcinoma growth by activating downstream mTOR-mitochondrial ROS signaling. SCIENCE ADVANCES 2024; 10:eadi2012. [PMID: 38241371 PMCID: PMC10798567 DOI: 10.1126/sciadv.adi2012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 12/20/2023] [Indexed: 01/21/2024]
Abstract
Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer. Inhibitors targeting the programmed cell death 1 (PD-1) immune checkpoint have improved MCC patient outcomes by boosting antitumor T cell immunity. Here, we identify PD-1 as a growth-promoting receptor intrinsic to MCC cells. In human MCC lines and clinical tumors, RT-PCR-based sequencing, immunoblotting, flow cytometry, and immunofluorescence analyses demonstrated PD-1 gene and protein expression by MCC cells. MCC-PD-1 ligation enhanced, and its inhibition or silencing suppressed, in vitro proliferation and in vivo tumor xenograft growth. Consistently, MCC-PD-1 binding to PD-L1 or PD-L2 induced, while antibody-mediated PD-1 blockade inhibited, protumorigenic mTOR signaling, mitochondrial (mt) respiration, and ROS generation. Last, pharmacologic inhibition of mTOR or mtROS reversed MCC-PD-1:PD-L1-dependent proliferation and synergized with PD-1 checkpoint blockade in suppressing tumorigenesis. Our results identify an MCC-PD-1-mTOR-mtROS axis as a tumor growth-accelerating mechanism, the blockade of which might contribute to clinical response in patients with MCC.
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Affiliation(s)
- Christina Martins
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Program of Glyco-Immunology and Oncology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Erik Rasbach
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Program of Glyco-Immunology and Oncology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Surgery, University Hospital Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Markus V. Heppt
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Dermatology, University Hospital Erlangen, Friedrich-Alexander-University (FAU), 91054 Erlangen, Germany
| | - Praveen Singh
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Program of Glyco-Immunology and Oncology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Zsofi Kulcsar
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Program of Glyco-Immunology and Oncology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Dermatology, University Hospital Bonn, 53127 Bonn, Germany
| | - Julia Holzgruber
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Program of Glyco-Immunology and Oncology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Dermatology and Venerology, Johannes Kepler University, 4020 Linz, Austria
| | - Asmi Chakraborty
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Program of Glyco-Immunology and Oncology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Kyla Mucciarone
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Sonja Kleffel
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Anne Brandenburg
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Dermatology, University Hospital Bonn, 53127 Bonn, Germany
| | - Wolfram Hoetzenecker
- Department of Dermatology and Venerology, Johannes Kepler University, 4020 Linz, Austria
| | - Nuh N. Rahbari
- Department of Surgery, University Hospital Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - James A. DeCaprio
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
- Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, MA 02138, USA
- Merkel Cell Carcinoma Center of Excellence, Dana-Farber/Brigham and Women’s Hospital Cancer Center, Boston, MA 02115, USA
| | - Manisha Thakuria
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Merkel Cell Carcinoma Center of Excellence, Dana-Farber/Brigham and Women’s Hospital Cancer Center, Boston, MA 02115, USA
| | - George F. Murphy
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Matthew R. Ramsey
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Christian Posch
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Dermatology, Vienna Healthcare Group, 1130 Vienna, Austria
- Faculty of Medicine, Sigmund Freud University Vienna, 1020 Vienna, Austria
- Department of Dermatology and Allergy, School of Medicine, Technical University of Munich, 81675 Munich, Germany
| | - Steven R. Barthel
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Program of Glyco-Immunology and Oncology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Tobias Schatton
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Program of Glyco-Immunology and Oncology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
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6
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Craig AW, Frieboes HB, Videira PA. Advancing cancer immunotherapy: from innovative preclinical models to clinical insights. Sci Rep 2024; 14:1205. [PMID: 38216668 PMCID: PMC10786836 DOI: 10.1038/s41598-024-51704-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2024] Open
Affiliation(s)
- Andrew W Craig
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
- Cancer Biology and Genetics Division, Queen's Cancer Research Institute, Kingston, ON, Canada.
| | - Hermann B Frieboes
- Department of Bioengineering, University of Louisville, Louisville, KY, USA.
- U of L Health - Brown Cancer Center, University of Louisville, Louisville, KY, USA.
- Center for Predictive Medicine, University of Louisville, Louisville, KY, USA.
| | - Paula A Videira
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
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7
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Hajibabaei S, Sotoodehnejadnematalahi F, Nafissi N, Zeinali S, Azizi M. Aberrant promoter hypermethylation of miR-335 and miR-145 is involved in breast cancer PD-L1 overexpression. Sci Rep 2023; 13:1003. [PMID: 36653507 PMCID: PMC9849328 DOI: 10.1038/s41598-023-27415-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 01/02/2023] [Indexed: 01/19/2023] Open
Abstract
PD-L1 is one of the most important immune checkpoint molecules in breast cancer that plays an important role in suppressing the immune system when confronted with tumor cells and is regulated by various microRNAs. Among them, microRNA-335-3p and microRNA-145-5p, regulated by DNA methylation, have tumor suppressor activities. We studied the role of miR-335 and -145 on PD-L1 suppression in breast cancer. The expression of miR-355 and miR-145 was significantly downregulated in BC tissues and cell lines compared to their controls, and their downregulation was negatively correlated with PD-L1 overexpression. In-silico and luciferase reporter systems confirmed that miR-335 and -145 target PD-L1. In BC tissues and cell lines, cancer-specific methylation was found in CpG-rich areas upstream of miR-335 and-145, and up-regulation of PD-L1 expression was connected with hypermethylation (r = 0.4089, P = 0.0147, and r = 0.3373, P = 0.0475, respectively). The higher levels of miR-355 and -145 in BC cells induced apoptosis, arrested the cell cycle, and reduced proliferation significantly. In summary, we found that miR-335 and -145 are novel tumor suppressors inactivated in BC, and these miRs may serve as potential therapeutic targets for breast cancer treatment.
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Affiliation(s)
- Sara Hajibabaei
- Department of Biology, School of Basic Science, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | | | - Nahid Nafissi
- Breast Surgery Department, Iran University of Medical Sciences, Tehran, Iran
| | - Sirous Zeinali
- Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, 69th Pasteur Street, Kargar Avenue, Tehran, Iran
| | - Masoumeh Azizi
- Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, 69th Pasteur Street, Kargar Avenue, Tehran, Iran.
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8
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Al-Saafeen BH, Al-Sbiei A, Bashir G, Mohamed YA, Masad RJ, Fernandez-Cabezudo MJ, al-Ramadi BK. Attenuated Salmonella potentiate PD-L1 blockade immunotherapy in a preclinical model of colorectal cancer. Front Immunol 2022; 13:1017780. [PMID: 36605208 PMCID: PMC9807881 DOI: 10.3389/fimmu.2022.1017780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 11/24/2022] [Indexed: 12/24/2022] Open
Abstract
The use of immune checkpoint inhibitors to treat cancer resulted in unprecedented and durable clinical benefits. However, the response rate among patients remains rather modest. Previous work from our laboratory demonstrated the efficacy of using attenuated bacteria as immunomodulatory anti-cancer agents. The current study investigated the potential of utilizing a low dose of attenuated Salmonella typhimurium to enhance the efficacy of PD-L1 blockade in a relatively immunogenic model of colon cancer. The response of MC38 tumors to treatment with αPD-L1 monoclonal antibody (mAb) was variable, with only 30% of the mice being responsive. Combined treatment with αPD-L1 mAb and Salmonella resulted in 75% inhibition of tumor growth in 100% of animals. Mechanistically, the enhanced response correlated with a decrease in the percentage of tumor-associated granulocytic cells, upregulation in MHC class II expression by intratumoral monocytes and an increase in tumor infiltration by effector T cells. Collectively, these alterations resulted in improved anti-tumor effector responses and increased apoptosis within the tumor. Thus, our study demonstrates that a novel combination treatment utilizing attenuated Salmonella and αPD-L1 mAb could improve the outcome of immunotherapy in colorectal cancer.
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Affiliation(s)
- Besan H. Al-Saafeen
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Ashraf Al-Sbiei
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Ghada Bashir
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Yassir A. Mohamed
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Razan J. Masad
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Maria J. Fernandez-Cabezudo
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates,Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Basel K. al-Ramadi
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates,Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates,*Correspondence: Basel K. al-Ramadi,
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