1
|
Vaddi PK, Osborne DG, Nicklawsky A, Williams NK, Menon DR, Smith D, Mayer J, Reid A, Domenico J, Nguyen GH, Robinson WA, Ziman M, Gao D, Zhai Z, Fujita M. CTLA4 mRNA is downregulated by miR-155 in regulatory T cells, and reduced blood CTLA4 levels are associated with poor prognosis in metastatic melanoma patients. Front Immunol 2023; 14:1173035. [PMID: 37197667 PMCID: PMC10183574 DOI: 10.3389/fimmu.2023.1173035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/17/2023] [Indexed: 05/19/2023] Open
Abstract
Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is an immune checkpoint expressed in regulatory T (Treg) cells and activated T lymphocytes. Despite its potential as a treatment strategy for melanoma, CTLA-4 inhibition has limited efficacy. Using data from The Cancer Genome Atlas (TCGA) melanoma database and another dataset, we found that decreased CTLA4 mRNA was associated with a poorer prognosis in metastatic melanoma. To investigate further, we measured blood CTLA4 mRNA in 273 whole-blood samples from an Australian cohort and found that it was lower in metastatic melanoma than in healthy controls and associated with worse patient survival. We confirmed these findings using Cox proportional hazards model analysis and another cohort from the US. Fractionated blood analysis revealed that Treg cells were responsible for the downregulated CTLA4 in metastatic melanoma patients, which was confirmed by further analysis of published data showing downregulated CTLA-4 surface protein expression in Treg cells of metastatic melanoma compared to healthy donors. Mechanistically, we found that secretomes from human metastatic melanoma cells downregulate CTLA4 mRNA at the post-transcriptional level through miR-155 while upregulating FOXP3 expression in human Treg cells. Functionally, we demonstrated that CTLA4 expression inhibits the proliferation and suppressive function of human Treg cells. Finally, miR-155 was found to be upregulated in Treg cells from metastatic melanoma patients compared to healthy donors. Our study provides new insights into the underlying mechanisms of reduced CTLA4 expression observed in melanoma patients, demonstrating that post-transcriptional silencing of CTLA4 by miRNA-155 in Treg cells may play a critical role. Since CTLA-4 expression is downregulated in non-responder melanoma patients to anti-PD-1 immunotherapy, targeting miRNA-155 or other factors involved in regulating CTLA4 expression in Treg cells without affecting T cells could be a potential strategy to improve the efficacy of immunotherapy in melanoma. Further research is needed to understand the molecular mechanisms regulating CTLA4 expression in Treg cells and identify potential therapeutic targets for enhancing immune-based therapies.
Collapse
Affiliation(s)
- Prasanna Kumar Vaddi
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Douglas Grant Osborne
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Andrew Nicklawsky
- University of Colorado Cancer Center Biostatistics Core, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Nazanin K. Williams
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Dinoop Ravindran Menon
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Derek Smith
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Jonathan Mayer
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Anna Reid
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Joanne Domenico
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Giang Huong Nguyen
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - William A. Robinson
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Melanie Ziman
- School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia
- School of Biomedical Science, University of Western Australia, Perth, WA, Australia
| | - Dexiang Gao
- University of Colorado Cancer Center Biostatistics Core, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Zili Zhai
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Mayumi Fujita
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Immunology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Veterans Affairs Medical Center, VA Eastern Colorado Health Care System, Aurora, CO, United States
- *Correspondence: Mayumi Fujita,
| |
Collapse
|
2
|
Ravindran Menon D, Li Y, Yamauchi T, Osborne DG, Vaddi PK, Wempe MF, Zhai Z, Fujita M. EGCG Inhibits Tumor Growth in Melanoma by Targeting JAK-STAT Signaling and Its Downstream PD-L1/PD-L2-PD1 Axis in Tumors and Enhancing Cytotoxic T-Cell Responses. Pharmaceuticals (Basel) 2021; 14:1081. [PMID: 34832863 PMCID: PMC8618268 DOI: 10.3390/ph14111081] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/19/2021] [Accepted: 10/21/2021] [Indexed: 12/13/2022] Open
Abstract
Over the last decade, therapies targeting immune checkpoints, such as programmed death-1 (PD-1), have revolutionized the field of cancer immunotherapy. However, low response rates and immune-related adverse events remain a major concern. Here, we report that epigallocatechin gallate (EGCG), the most abundant catechin in green tea, inhibits melanoma growth by modulating an immune response against tumors. In vitro experiments revealed that EGCG treatment inhibited interferon-gamma (IFN-γ)-induced PD-L1 and PD-L2 expression and JAK-STAT signaling. We confirmed that this effect was driven by inhibiting STAT1 gene expression and STAT1 phosphorylation, thereby downregulating the PD-L1/PD-L2 transcriptional regulator IRF1 in both human and mouse melanoma cells. Animal studies revealed that the in vivo tumor-inhibitory effect of EGCG was through CD8+ T cells and that the inhibitory effect of EGCG was comparable to anti-PD-1 therapy. However, their mechanisms of action were different. Dissimilar to anti-PD-1 treatment that blocks PD-1/PD-L1 interaction, EGCG inhibited JAK/STAT signaling and PD-L1 expression in tumor cells, leading to the re-activation of T cells. In summary, we demonstrate that EGCG enhances anti-tumor immune responses by inhibiting JAK-STAT signaling in melanoma. EGCG could be used as an alternative treatment strategy to target the PD-L1/PD-L2-PD-1 axis in cancers.
Collapse
Affiliation(s)
- Dinoop Ravindran Menon
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (D.R.M.); (Y.L.); (T.Y.); (D.G.O.); (P.K.V.); (Z.Z.)
| | - Yang Li
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (D.R.M.); (Y.L.); (T.Y.); (D.G.O.); (P.K.V.); (Z.Z.)
| | - Takeshi Yamauchi
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (D.R.M.); (Y.L.); (T.Y.); (D.G.O.); (P.K.V.); (Z.Z.)
| | - Douglas Grant Osborne
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (D.R.M.); (Y.L.); (T.Y.); (D.G.O.); (P.K.V.); (Z.Z.)
| | - Prasanna Kumar Vaddi
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (D.R.M.); (Y.L.); (T.Y.); (D.G.O.); (P.K.V.); (Z.Z.)
| | - Michael F Wempe
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA;
| | - Zili Zhai
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (D.R.M.); (Y.L.); (T.Y.); (D.G.O.); (P.K.V.); (Z.Z.)
| | - Mayumi Fujita
- Department of Dermatology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (D.R.M.); (Y.L.); (T.Y.); (D.G.O.); (P.K.V.); (Z.Z.)
- Department of Veterans Affairs Medical Center, VA Eastern Colorado Health Care System, Aurora, CO 80045, USA
- Department of Immunology & Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| |
Collapse
|
3
|
Vaddi PK, Stamnes MA, Cao H, Chen S. Elimination of SOX2/OCT4-Associated Prostate Cancer Stem Cells Blocks Tumor Development and Enhances Therapeutic Response. Cancers (Basel) 2019; 11:cancers11091331. [PMID: 31500347 PMCID: PMC6769476 DOI: 10.3390/cancers11091331] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 08/29/2019] [Accepted: 09/04/2019] [Indexed: 12/15/2022] Open
Abstract
SOX2 and OCT4 are key regulators of embryonic stem cell pluripotency. They are overexpressed in prostate cancers and have been associated with cancer stem cell (CSC) properties. However, reliable tools for detecting and targeting SOX2/OCT4-overexpressing cells are lacking, limiting our understanding of their roles in prostate cancer initiation, progression, and therapeutic resistance. Here, we show that a fluorescent reporter called SORE6 can identify SOX2/OCT4-overexpressing prostate cancer cells. Among tumor cells, the SORE6 reporter identified a small fraction with CSC hallmarks: rapid self-renewal, the capability to form tumors and metastasize, and resistance to chemotherapies. Transcriptome and biochemical analyses identified PI3K/AKT signaling as critical for maintaining the SORE6+ population. Moreover, a SORE6-driven herpes simplex virus thymidine kinase (TK) expression construct could selectively ablate SORE6+ cells in tumors, blocking tumor initiation and progression, and sensitizing tumors to chemotherapy. This study demonstrates a key role of SOX2/OCT4-associated prostate cancer stem cells in tumor development and therapeutic resistance, and identifies the SORE6 reporter system as a useful tool for characterizing CSCs functions in a native tumor microenvironment.
Collapse
Affiliation(s)
- Prasanna Kumar Vaddi
- The Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
| | - Mark A Stamnes
- The Department of Molecular Physiology and Physics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
| | - Huojun Cao
- The Department of Endodontics, College of Dentistry and Dental Clinics, University of Iowa, Iowa City, IA 52242, USA.
| | - Songhai Chen
- The Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
- The Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
- The Holden Comprehensive Cancer Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
| |
Collapse
|