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Penetra M, Arnaut LG, Gomes-da-Silva LC. Trial watch: an update of clinical advances in photodynamic therapy and its immunoadjuvant properties for cancer treatment. Oncoimmunology 2023; 12:2226535. [PMID: 37346450 PMCID: PMC10281486 DOI: 10.1080/2162402x.2023.2226535] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/12/2023] [Accepted: 06/13/2023] [Indexed: 06/23/2023] Open
Abstract
Photodynamic therapy (PDT) is a medical treatment used to target solid tumors, where the administration of a photosensitizing agent and light generate reactive oxygen species (ROS), thus resulting in strong oxidative stress that selectively damages the illuminated tissues. Several preclinical studies have demonstrated that PDT can prime the immune system to recognize and attack cancer cells throughout the body. However, there is still limited evidence of PDT-mediated anti-tumor immunity in clinical settings. In the last decade, several clinical trials on PDT for cancer treatment have been initiated, indicating that significant efforts are being made to improve current PDT protocols. However, most of these studies disregarded the immunological dimension of PDT. The immunomodulatory properties of PDT can be combined with standard therapy and/or emerging immunotherapies, such as immune checkpoint blockers (ICBs), to achieve better disease control. Combining PDT with immunotherapy has shown synergistic effects in some preclinical models. However, the value of this combination in patients is still unknown, as the first clinical trials evaluating the combination of PDT with ICBs are just being initiated. Overall, this Trial Watch provides a summary of recent clinical information on the immunomodulatory properties of PDT and ongoing clinical trials using PDT to treat cancer patients. It also discusses the future perspectives of PDT for oncological indications.
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Affiliation(s)
- Mafalda Penetra
- CQC - Coimbra Chemistry Center, Universidade de Coimbra, Coimbra, Portugal
| | - Luís G. Arnaut
- CQC - Coimbra Chemistry Center, Universidade de Coimbra, Coimbra, Portugal
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Latest Innovations and Nanotechnologies with Curcumin as a Nature-Inspired Photosensitizer Applied in the Photodynamic Therapy of Cancer. Pharmaceutics 2021; 13:pharmaceutics13101562. [PMID: 34683855 PMCID: PMC8539945 DOI: 10.3390/pharmaceutics13101562] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 09/15/2021] [Accepted: 09/22/2021] [Indexed: 12/27/2022] Open
Abstract
In the context of the high incidence of cancer worldwide, state-of-the-art photodynamic therapy (PDT) has entered as a usual protocol of attempting to eradicate cancer as a minimally invasive procedure, along with pharmacological resources and radiation therapy. The photosensitizer (PS) excited at certain wavelengths of the applied light source, in the presence of oxygen releases several free radicals and various oxidation products with high cytotoxic potential, which will lead to cell death in irradiated cancerous tissues. Current research focuses on the potential of natural products as a superior generation of photosensitizers, which through the latest nanotechnologies target tumors better, are less toxic to neighboring tissues, but at the same time, have improved light absorption for the more aggressive and widespread forms of cancer. Curcumin incorporated into nanotechnologies has a higher intracellular absorption, a higher targeting rate, increased toxicity to tumor cells, accelerates the activity of caspases and DNA cleavage, decreases the mitochondrial activity of cancer cells, decreases their viability and proliferation, decreases angiogenesis, and finally induces apoptosis. It reduces the size of the primary tumor, reverses multidrug resistance in chemotherapy and decreases resistance to radiation therapy in neoplasms. Current research has shown that the use of PDT and nanoformulations of curcumin has a modulating effect on ROS generation, so light or laser irradiation will lead to excessive ROS growth, while nanocurcumin will reduce the activation of ROS-producing enzymes or will determine the quick removal of ROS, seemingly opposite but synergistic phenomena by inducing neoplasm apoptosis, but at the same time, accelerating the repair of nearby tissue. The latest curcumin nanoformulations have a huge potential to optimize PDT, to overcome major side effects, resistance to chemotherapy, relapses and metastases. All the studies reviewed and presented revealed great potential for the applicability of nanoformulations of curcumin and PDT in cancer therapy.
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Smithen DA, Monro S, Pinto M, Roque J, Diaz-Rodriguez RM, Yin H, Cameron CG, Thompson A, McFarland SA. Bis[pyrrolyl Ru(ii)] triads: a new class of photosensitizers for metal-organic photodynamic therapy. Chem Sci 2020; 11:12047-12069. [PMID: 33738086 PMCID: PMC7953431 DOI: 10.1039/d0sc04500d] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 10/06/2020] [Indexed: 12/22/2022] Open
Abstract
A new family of ten dinuclear Ru(ii) complexes based on the bis[pyrrolyl Ru(ii)] triad scaffold, where two Ru(bpy)2 centers are separated by a variety of organic linkers, was prepared to evaluate the influence of the organic chromophore on the spectroscopic and in vitro photodynamic therapy (PDT) properties of the compounds. The bis[pyrrolyl Ru(ii)] triads absorbed strongly throughout the visible region, with several members having molar extinction coefficients (ε) ≥ 104 at 600-620 nm and longer. Phosphorescence quantum yields (Φ p) were generally less than 0.1% and in some cases undetectable. The singlet oxygen quantum yields (Φ Δ) ranged from 5% to 77% and generally correlated with their photocytotoxicities toward human leukemia (HL-60) cells regardless of the wavelength of light used. Dark cytotoxicities varied ten-fold, with EC50 values in the range of 10-100 μM and phototherapeutic indices (PIs) as large as 5400 and 260 with broadband visible (28 J cm-2, 7.8 mW cm-2) and 625 nm red (100 J cm-2, 42 mW cm-2) light, respectively. The bis[pyrrolyl Ru(ii)] triad with a pyrenyl linker (5h) was especially potent, with an EC50 value of 1 nM and PI > 27 000 with visible light and subnanomolar activity with 625 nm light (100 J cm-2, 28 mW cm-2). The lead compound 5h was also tested in a tumor spheroid assay using the HL60 cell line and exhibited greater photocytotoxicity in this more resistant model (EC50 = 60 nM and PI > 1200 with 625 nm light) despite a lower dark cytotoxicity. The in vitro PDT effects of 5h extended to bacteria, where submicromolar EC50 values and PIs >300 against S. mutans and S. aureus were obtained with visible light. This activity was attenuated with 625 nm red light, but PIs were still near 50. The ligand-localized 3ππ* state contributed by the pyrenyl linker of 5h likely plays a key role in its phototoxic effects toward cancer cells and bacteria.
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Affiliation(s)
- Deborah A Smithen
- Department of Chemistry , Dalhousie University , P. O. Box 15000 , Halifax , NS B3H 4R2 , Canada .
| | - Susan Monro
- Department of Chemistry , Acadia University , Wolfville , NS B4P 2R6 , Canada
| | - Mitch Pinto
- Department of Chemistry , Acadia University , Wolfville , NS B4P 2R6 , Canada
| | - John Roque
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , PO Box 26170 , Greensboro , NC 27402-6170 , USA.,Department of Chemistry and Biochemistry , The University of Texas at Arlington , 700 Planetarium Pl , Arlington , TX 76019-0065 , USA .
| | - Roberto M Diaz-Rodriguez
- Department of Chemistry , Dalhousie University , P. O. Box 15000 , Halifax , NS B3H 4R2 , Canada .
| | - Huimin Yin
- Department of Chemistry , Acadia University , Wolfville , NS B4P 2R6 , Canada
| | - Colin G Cameron
- Department of Chemistry and Biochemistry , The University of Texas at Arlington , 700 Planetarium Pl , Arlington , TX 76019-0065 , USA .
| | - Alison Thompson
- Department of Chemistry , Dalhousie University , P. O. Box 15000 , Halifax , NS B3H 4R2 , Canada .
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry , The University of Texas at Arlington , 700 Planetarium Pl , Arlington , TX 76019-0065 , USA .
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Lifshits LM, Roque Iii JA, Konda P, Monro S, Cole HD, von Dohlen D, Kim S, Deep G, Thummel RP, Cameron CG, Gujar S, McFarland SA. Near-infrared absorbing Ru(ii) complexes act as immunoprotective photodynamic therapy (PDT) agents against aggressive melanoma. Chem Sci 2020; 11:11740-11762. [PMID: 33976756 PMCID: PMC8108386 DOI: 10.1039/d0sc03875j] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/04/2020] [Indexed: 12/15/2022] Open
Abstract
Mounting evidence over the past 20 years suggests that photodynamic therapy (PDT), an anticancer modality known mostly as a local treatment, has the capacity to invoke a systemic antitumor immune response, leading to protection against tumor recurrence. For aggressive cancers such as melanoma, where chemotherapy and radiotherapy are ineffective, immunomodulating PDT as an adjuvant to surgery is of interest. Towards the development of specialized photosensitizers (PSs) for treating pigmented melanomas, nine new near-infrared (NIR) absorbing PSs based on a Ru(ii) tris-heteroleptic scaffold [Ru(NNN)(NN)(L)]Cln, were explored. Compounds 2, 6, and 9 exhibited high potency toward melanoma cells, with visible EC50 values as low as 0.292–0.602 μM and PIs as high as 156–360. Single-micromolar phototoxicity was obtained with NIR-light (733 nm) with PIs up to 71. The common feature of these lead NIR PSs was an accessible low-energy triplet intraligand (3IL) excited state for high singlet oxygen (1O2) quantum yields (69–93%), which was only possible when the photosensitizing 3IL states were lower in energy than the lowest triplet metal-to-ligand charge transfer (3MLCT) excited states that typically govern Ru(ii) polypyridyl photophysics. PDT treatment with 2 elicited a pro-inflammatory response alongside immunogenic cell death in mouse B16F10 melanoma cells and proved safe for in vivo administration (maximum tolerated dose = 50 mg kg−1). Female and male mice vaccinated with B16F10 cells that were PDT-treated with 2 and challenged with live B16F10 cells exhibited 80 and 55% protection from tumor growth, respectively, leading to significantly improved survival and excellent hazard ratios of ≤0.2. Ru(ii) photosensitizers (PSs) destroy aggressive melanoma cells, triggering an immune response that leads to protection against tumor challenge and mouse survival.![]()
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Affiliation(s)
- Liubov M Lifshits
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019-0065 USA
| | - John A Roque Iii
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019-0065 USA .,Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro Greensboro North Carolina 27402 USA
| | - Prathyusha Konda
- Department of Microbiology and Immunology, Dalhousie University Halifax Nova Scotia B3H 1X5 Canada
| | - Susan Monro
- Department of Chemistry, Acadia University Wolfville Nova Scotia B4P 2R6 Canada
| | - Houston D Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019-0065 USA
| | - David von Dohlen
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro Greensboro North Carolina 27402 USA
| | - Susy Kim
- Department of Cancer Biology, Wake Forest School of Medicine Winston Salem NC 27157 USA
| | - Gagan Deep
- Department of Cancer Biology, Wake Forest School of Medicine Winston Salem NC 27157 USA
| | - Randolph P Thummel
- Department of Chemistry, University of Houston 112 Fleming Building Houston Texas 77204-5003 USA
| | - Colin G Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019-0065 USA
| | - Shashi Gujar
- Department of Microbiology and Immunology, Dalhousie University Halifax Nova Scotia B3H 1X5 Canada .,Department of Pathology, Dalhousie University Halifax Nova Scotia B3H 1X5 Canada.,Department of Biology, Dalhousie University Halifax Nova Scotia B3H 1X5 Canada.,Beatrice Hunter Cancer Research Institute Halifax Nova Scotia B3H 4R2 Canada
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019-0065 USA
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