1
|
Ge Y, Peng Y, Xie R, Luo Y, Li Y, Chen G. Visible Light-Mediated Late-Stage Thioetherification of Mercaptopurine Derivatives. Chemistry 2024; 30:e202401774. [PMID: 38923704 DOI: 10.1002/chem.202401774] [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: 05/06/2024] [Revised: 06/22/2024] [Accepted: 06/23/2024] [Indexed: 06/28/2024]
Abstract
We disclose herein a novel and general radical approach to alkylthiopurines, encompassing 4 types of thiopurines, as well as their corresponding ribosides. This strategy is achieved through visible light-mediated late-stage functionalization of the sulfur atoms of mercaptopurines. The in situ-generated disulfide was proposed as the pivotal neutral intermediate for this transformation. We present herein a novel photo-mediated homolytic C-S bond formation for the preparation of alkylthiopurines and alkylthiopurine nucleosides. Despite the presence of reactive sites for the Minisci reaction, chemoselective S-alkylation remained the predominant pathway. This method allows for the late-stage introduction of a broad spectrum of alkyl groups onto the sulfur atom of unprotective mercaptopurine derivatives, encompassing 2-, 6-, and 8-mercaptopurine rings. Organoborons serve as efficient and eco-friendly alkylating reagents, providing advantages in terms of readily availability, stability, and reduced toxicity. Further derivatization of the thioetherified nucleosides, together with anti-tumor assays, led to the discovery of potent anti-tumor agents with an IC50 value reaching 6.1 μM (Comp. 31 for Jurkat).
Collapse
Affiliation(s)
- Yuhua Ge
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, P. R.China
| | - Yijiang Peng
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, P. R.China
| | - Ruoqian Xie
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, P. R.China
| | - Yang Luo
- Shanghai Key Laboratory for Molecular Engineer of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
| | - Yangyan Li
- Shanghai Key Laboratory for Molecular Engineer of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
| | - Gang Chen
- Shanghai Key Laboratory for Molecular Engineer of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
- Key Laboratory of Green and High-value Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, Qinghai, 810008, P. R. China
| |
Collapse
|
2
|
Cui X, Fan J, Lyu Y, Zhou X, Meng Q, Zhang C. Quasi-intrinsic thiobase derivatives as potential targeted photosensitizers in two-photon photodynamic therapy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 316:124311. [PMID: 38663131 DOI: 10.1016/j.saa.2024.124311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 04/08/2024] [Accepted: 04/17/2024] [Indexed: 05/15/2024]
Abstract
In this study, a set of potential quasi-intrinsic photosensitizers for two-photon photodynamic therapy (PDT) are proposed based on the unnatural 2-amino-8-(1'-β-ᴅ-2'-deoxyribofuranosyl)-imidazo[1,2-ɑ]-1,3,5-triazin-4(8H)-one (P), which is paired with the 6-amino-5-nitro-3-(1'-β-ᴅ-2'-deoxyribofuranosyl)-2(1H)-pyridone (Z) and can specifically recognize breast and liver cancer cells. Herein, the effects of sulfur substitution and electron-donating/electron-withdrawing groups on the photophysical properties in aqueous solution are systematically investigated. The one- and two-photon absorption spectra evidence that the modifications could result in red-shifted absorption wavelength and large two-photon absorption cross-section, which contributes to selective excitation and provides effective PDT for deep-seated tissues. To ensure the efficient triplet state population, the singlet-triplet energy gaps and spin-orbit coupling constants were examined, which is responsible for a rapid intersystem crossing rate. Furthermore, these thiobase derivatives are characterized by the long-lived T1 state and the large energy gap for radiationless transition to ensure the generation of cytotoxic singlet oxygen.
Collapse
Affiliation(s)
- Xixi Cui
- School of Physics and Electronics, Shandong Normal University, Jinan 250358, PR China
| | - Jianzhong Fan
- School of Physics and Electronics, Shandong Normal University, Jinan 250358, PR China
| | - Yongkang Lyu
- School of Physics and Electronics, Shandong Normal University, Jinan 250358, PR China
| | - Xucong Zhou
- School of Basic Medical Sciences, Shandong Second Medical University, Weifang 261053, PR China
| | - Qingtian Meng
- School of Physics and Electronics, Shandong Normal University, Jinan 250358, PR China.
| | - Changzhe Zhang
- School of Physics and Electronics, Shandong Normal University, Jinan 250358, PR China.
| |
Collapse
|
3
|
Khatun MN, Nandy S, Roy H, Ghosh SS, Kumar S, Iyer PK. Sulphur-atom positional engineering in perylenimide: structure-property relationships and H-aggregation directed type-I photodynamic therapy. Chem Sci 2024; 15:9298-9317. [PMID: 38903228 PMCID: PMC11186329 DOI: 10.1039/d4sc01180e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 05/10/2024] [Indexed: 06/22/2024] Open
Abstract
An innovative design strategy of placing sulfur (S)-atoms within the pendant functional groups and at carbonyl positions in conventional perylenimide (PNI-O) has been demonstrated to investigate the condensed state structure-property relationship and potential photodynamic therapy (PDT) application. Incorporation of simply S-atoms at the peri-functionalized perylenimide (RPNI-O) leads to an aggregation-induced enhanced emission luminogen (AIEEgen), 2-hexyl-8-(thianthren-1-yl)-1H-benzo[5,10]anthra[2,1,9-def]isoquinoline-1,3(2H)-dione (API), which achieves a remarkable photoluminescence quantum yield (Φ PL) of 0.85 in aqueous environments and established novel AIE mechanisms. Additionally, substitution of the S-atom at the carbonyl position in RPNI-O leads to thioperylenimides (RPNI-S): 2-hexyl-8-phenyl-1H-benzo[5,10]anthra[2,1,9-def]isoquinoline-1,3(2H)-dithione (PPIS), 8-([2,2'-bithiophen]-5-yl)-2-hexyl-1H-benzo[5,10]anthra[2,1,9-def]isoquinoline-1,3(2H)-dithione (THPIS), and 2-hexyl-8-(thianthren-1-yl)-1H-benzo[5,10]anthra[2,1,9-def]isoquinoline-1,3(2H)-dithion (APIS), with distinct photophysical properties (enlarged spin-orbit coupling (SOC) and Φ PL ≈ 0.00), and developed diverse potent photosensitizers (PSs). The present work provides a novel SOC enhancement mechanism via pronounced H-aggregation. Surprisingly, the lowest singlet oxygen quantum yield (Φ Δ) and theoretical calculation suggest the specific type-I PDT for RPNI-S. Interestingly, RPNI-S efficiently produces superoxide (O2˙-) due to its remarkably lower Gibbs free energy (ΔG) values (THPIS: -40.83 kcal mol-1). The non-toxic and heavy-atom free very specific thio-based PPIS and THPIS PSs showed selective and efficient PDT under normoxia, as a rare example.
Collapse
Affiliation(s)
- Mst Nasima Khatun
- Department of Chemistry, Indian Institute of Technology Guwahati Guwahati 781039 Assam India +91-3612582349
| | - Satyendu Nandy
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati Guwahati 781039 Assam India
| | - Hirakjyoti Roy
- Centre for Nanotechnology, Indian Institute of Technology Guwahati Guwahati 781039 Assam India
| | - Siddhartha Sankar Ghosh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati Guwahati 781039 Assam India
- Centre for Nanotechnology, Indian Institute of Technology Guwahati Guwahati 781039 Assam India
| | - Sachin Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati Guwahati 781039 Assam India
| | - Parameswar Krishnan Iyer
- Department of Chemistry, Indian Institute of Technology Guwahati Guwahati 781039 Assam India +91-3612582349
- Centre for Nanotechnology, Indian Institute of Technology Guwahati Guwahati 781039 Assam India
| |
Collapse
|
4
|
Sato R, Yamada Y, Kashihara W, Nishihara T, Tanabe K, Xu YZ, Suzuki T. Excited state properties of 5-fluoro-4-thiouridine derivative †. Photochem Photobiol 2024; 100:434-442. [PMID: 38312100 DOI: 10.1111/php.13918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/06/2024]
Abstract
The excited state properties of thionated 5-fluorouridine (2',3',5'-tri-O-acetyl-5-fluoro-4-thiouridine; ta5F4TUrd), synthesized with Lawesson's reagent, have been intensively investigated with nanosecond transient absorption spectroscopy, time-resolved thermal lensing, near-infrared emission, and quantum chemical calculation. The intrinsic triplet lifetime of ta5F4TUrd was determined to be4.2 ± 0.7 μs in acetonitrile, and the formation quantum yield of the excited triplet state was as large as0.79 ± 0.01 . The quenching rate constants of the triplet ta5F4TUrd by the dissolved oxygen molecule and by the self-quenching process were found to be nearly equal to the diffusion-controlled rate of acetonitrile. The quantum yield of the singlet molecular oxygen produced through energy transfer between the triplet ta5F4TUrd and the dissolved oxygen,Φ Δ , was successfully determined to be0.61 ± 0.02 under the oxygen-saturated condition. From the oxygen concentration dependence of theΦ Δ value, the fraction of triplet ta5F4TUrd quenched by dissolved oxygen which gives rise to the 1 O2 * formation,S Δ , was successfully obtained to be0.78 ± 0.01 , which was the largest among the thionucleobases and the thionucleosides reported so far. This could be due to the lower energy and/or the ππ* character of the triplet state.
Collapse
Affiliation(s)
- Rin Sato
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
| | - Yoshino Yamada
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
| | - Wataru Kashihara
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
| | - Tatsuya Nishihara
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
| | - Kazuhito Tanabe
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
| | - Yao-Zhong Xu
- School of Life, Health and Chemical Sciences, The Open University, Keynes, UK
| | - Tadashi Suzuki
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
| |
Collapse
|
5
|
Ortiz-Rodríguez LA, Hoehn SJ, Acquah C, Abbass N, Waidmann L, Crespo-Hernández CE. Femtosecond intersystem crossing to the reactive triplet state of the 2,6-dithiopurine skin cancer photosensitizer. Phys Chem Chem Phys 2021; 23:25048-25055. [PMID: 34730146 DOI: 10.1039/d1cp04415j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Site-selected sulfur-substituted nucleobases are a class of all organic, heavy-atom-free photosensitizers for photodynamic therapy applications that exhibit excellent photophysical properties such as strong absorption in the ultraviolet-A region of the electromagnetic spectrum, near-unity triplet yields, and a high yield of singlet oxygen generation. Recent investigations on doubly thionated nucleobases, 2,4-dithiothymine, 2,4-dithiouracil, and 2,6-dithiopurine, demonstrated that these set of dithionated nucleobases outperform the photodynamic efficacy exhibit by 4-thiothymidine-the most widely studied singly substituted thiobase to date. Out of the three dithionated nucleobases, 2,6-dithiopurine was shown to be the most effective, exhibiting inhibition of cell proliferation of up to 63% when combined with a low UVA dose of 5 J cm-2. In this study, we elucidated the electronic relaxation pathways leading to the population of the reactive triplet state of 2,6-dithiopurine. 2,6-Dithiopurine populates the triplet manifold in less than 150 fs, reaching the nπ* triplet state minimum within a lifetime of 280 ± 50 fs. Subsequently, the population in the nπ* triplet state minimum internally converts to the long-lived ππ* triplet state within a lifetime of 3 ± 1 ps. The relatively slow internal conversion lifetime is associated with major conformational relaxation in going from the nπ* to ππ* triplet state minimum. A unity triplet yield of 1.0 ± 0.1 is measured.
Collapse
Affiliation(s)
| | - Sean J Hoehn
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Chris Acquah
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Nadia Abbass
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Lidia Waidmann
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106, USA.
| | | |
Collapse
|
6
|
Nonoshita D, Kashihara W, Tanabe K, Isozaki T, Xu YZ, Suzuki T. Excited States of Thio-2'-deoxyuridine Bearing an Extended π-Conjugated System: 3',5'-Di- O-acetyl-5-phenylethynyl-4-thio-2'-deoxyuridine. J Phys Chem A 2021; 125:597-606. [PMID: 33307688 DOI: 10.1021/acs.jpca.0c09343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A new thio-2'-deoxyuridine with an extended π-conjugated group was successfully synthesized: 3',5'-di-O-acetyl-5-phenylethynyl-4-thio-2'-deoxyuridine. The thio-2'-deoxyuridine derivative has a large red-shifted absorption band in the UVA region and also shows fluorescence, a rare photo-property among thionucleobases/thionucleosides. The triplet-triplet absorption spectrum and the rate constants (the intrinsic decay rate constant of the triplet state, the self-quenching rate constant, and the quenching rate constant of the triplet state by an oxygen molecule) of the thio-2'-deoxyuridine were obtained by transient absorption spectroscopy. The quantum yield of intersystem crossing and the quantum yield of singlet molecular oxygen formation (ϕΔ) under an oxygen atmosphere were also determined. The ϕΔ value of the new thio-2'-deoxyuridine was found to be substantially higher than all reported values of other thio-2'-deoxyribonucleosides in low oxygen concentrations similar to cancer cell environments. The fluorescence quantum yield depended on the excitation wavelength, revealing certain photochemical reactions in the higher excited singlet states. However, when excited into the higher excited state with non-resonant two-photon absorption, the ϕΔ of the thio-2'-deoxyuridine derivative was found to remain sufficiently large. These findings should be very useful for the development of thio-2'-deoxyribonucleoside-based pharmaceuticals as DNA-specific photosensitizers for photochemotherapy.
Collapse
Affiliation(s)
- Daiki Nonoshita
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Fuchinobe, Chuo-ku, Sagamihara 252-5258, Kanagawa, Japan
| | - Wataru Kashihara
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Fuchinobe, Chuo-ku, Sagamihara 252-5258, Kanagawa, Japan
| | - Kazuhito Tanabe
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Fuchinobe, Chuo-ku, Sagamihara 252-5258, Kanagawa, Japan
| | - Tasuku Isozaki
- Division of Natural Sciences, College of Arts and Sciences, J. F. Oberlin University, Tokiwa-machi, Machida 194-0294, Tokyo, Japan
| | - Yao Zhong Xu
- School of Life, Health and Chemical Sciences, The Open University, Keynes MK7 6AA, U.K
| | - Tadashi Suzuki
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Fuchinobe, Chuo-ku, Sagamihara 252-5258, Kanagawa, Japan
| |
Collapse
|
7
|
Ortiz-Rodríguez LA, Crespo-Hernández CE. Thionated organic compounds as emerging heavy-atom-free photodynamic therapy agents. Chem Sci 2020; 11:11113-11123. [PMID: 34094354 PMCID: PMC8162790 DOI: 10.1039/d0sc04747c] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 09/15/2020] [Indexed: 12/13/2022] Open
Abstract
This minireview focuses on recent progress in developing heavy-atom-free photosensitizers based on the thionation of nucleic acid derivatives and other biocompatible organic compounds for prospective applications in photodynamic therapy. Particular attention is given to the use of thionated nucleobase derivatives as "one-two punch" photodynamic agents. These versatile photosensitizers can act as "Trojan horses" upon metabolization into DNA and exposure to activating light. Their incorporation into cellular DNA increases their selectivity and photodynamic efficacy against highly proliferating skin cancer tumor cells, while simultaneously enabling the use of low irradiation doses both in the presence and in the absence of molecular oxygen. Also reviewed are their primary photochemical reactions, modes of action, and photosensitization mechanisms. New developments of emerging thionated organic photosensitizers absorbing visible and near-infrared radiation are highlighted. Future research directions, as well as, other prospective applications of heavy-atom-free, thionated photosensitizers are discussed.
Collapse
|
8
|
Tang J, Wang L, Loredo A, Cole C, Xiao H. Single-atom replacement as a general approach towards visible-light/near-infrared heavy-atom-free photosensitizers for photodynamic therapy. Chem Sci 2020; 11:6701-6708. [PMID: 32953031 PMCID: PMC7473402 DOI: 10.1039/d0sc02286a] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 05/30/2020] [Indexed: 12/31/2022] Open
Abstract
Photodynamic therapy has become an emerging strategy for the treatment of cancer. This technology relies on the development of photosensitizers (PSs) that convert molecular oxygen to cytotoxic reactive oxygen species upon exposure to light. In this study, we have developed a facile and general strategy for obtaining visible light/near-infrared-absorbing PSs by performing a simple sulfur-for-oxygen replacement within existing fluorophores. Thionation of carbonyl groups within existing fluorophore cores leads to an improvement of the singlet oxygen quantum yield and molar absorption coefficient at longer wavelengths (deep to 600-800 nm). Additionally, these thio-based PSs lack dark cytotoxicity but exhibit significant phototoxicity against monolayer cancer cells and 3D multicellular tumor spheroids with IC50 in the micromolar range. To achieve tumor-specific delivery, we have conjugated these thio-based PSs to an antibody and demonstrated their tumor-specific therapeutic activity.
Collapse
Affiliation(s)
- Juan Tang
- Department of Chemistry , Rice University , 6100 Main Street , Houston , Texas 77005 , USA .
| | - Lushun Wang
- Department of Chemistry , Rice University , 6100 Main Street , Houston , Texas 77005 , USA .
| | - Axel Loredo
- Department of Chemistry , Rice University , 6100 Main Street , Houston , Texas 77005 , USA .
| | - Carson Cole
- Department of Chemistry , Rice University , 6100 Main Street , Houston , Texas 77005 , USA .
| | - Han Xiao
- Department of Chemistry , Rice University , 6100 Main Street , Houston , Texas 77005 , USA .
- Department of Biosciences , Rice University , 6100 Main Street , Houston , Texas 77005 , USA
- Department of Bioengineering , Rice University , 6100 Main Street , Houston , Texas 77005 , USA
| |
Collapse
|
9
|
Nguyen VN, Qi S, Kim S, Kwon N, Kim G, Yim Y, Park S, Yoon J. An Emerging Molecular Design Approach to Heavy-Atom-Free Photosensitizers for Enhanced Photodynamic Therapy under Hypoxia. J Am Chem Soc 2019; 141:16243-16248. [DOI: 10.1021/jacs.9b09220] [Citation(s) in RCA: 166] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Van-Nghia Nguyen
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Sujie Qi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Sangin Kim
- Department of Chemistry, Korea University, Seoul 02841, Republic of Korea
| | - Nahyun Kwon
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Gyoungmi Kim
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Yubin Yim
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Sungnam Park
- Department of Chemistry, Korea University, Seoul 02841, Republic of Korea
| | - Juyoung Yoon
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| |
Collapse
|
10
|
Miyata S, Tanabe S, Isozaki T, Xu YZ, Suzuki T. Characteristics of the excited triplet states of thiolated guanosine derivatives and singlet oxygen generation. Photochem Photobiol Sci 2018; 17:1469-1476. [PMID: 30280174 DOI: 10.1039/c8pp00240a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Thioguanine is sensitive to UVA light and generates singlet molecular oxygen (1O2*) when exposed to UVA. Three thioguanosine derivatives, 2',3',5'-tri-O-acetyl-6-thioguanosine (ta6TGuo), 2',3',5'-tri-O-acetyl-8-thioguanosine (ta8TGuo), and 2',3',5'-tri-O-acetyl-6,8-dithioguanosine (taDTGuo) were explored photophysically and photochemically. Nanosecond transient absorption and time-resolved near-infrared emission measurements were carried out to investigate the characteristics of their excited triplet states in acetonitrile solution. The quantum yield of intersystem crossing (ΦISC), the intrinsic decay rate constant (k0), the quenching rate constant by 3O2 (kq) and the self-quenching rate constant (kSQ) of their triplet states were all determined. From the precise analysis of the quantum yield of 1O2* generation (ΦΔ) against the concentration of dissolved molecular oxygen, the fraction of the triplet states quenched by dissolved oxygen which gives rise to 1O2* formation (SΔ) was successfully obtained with high accuracy. The ΦΔ values at low oxygen concentrations reveal that these thioguanosines, particularly taDTGuo, can still effectively generate 1O2* at low molecular oxygen concentrations like carcinomatous microenvironments. These findings indicate that taDTGuo would perform well as a potential agent for photo-induced cancer therapies.
Collapse
Affiliation(s)
- Shoma Miyata
- Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan.
| | | | | | | | | |
Collapse
|
11
|
Ashwood B, Pollum M, Crespo-Hernández CE. Photochemical and Photodynamical Properties of Sulfur-Substituted Nucleic Acid Bases. Photochem Photobiol 2018; 95:33-58. [PMID: 29978490 DOI: 10.1111/php.12975] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 06/28/2018] [Indexed: 12/25/2022]
Abstract
Sulfur-substituted nucleobases (a.k.a., thiobases) are among the world's leading prescriptions for chemotherapy and immunosuppression. Long-term treatment with azathioprine, 6-mercaptopurine and 6-thioguanine has been correlated with the photoinduced formation of carcinomas. Establishing an in-depth understanding of the photochemical properties of these prodrugs may provide a route to overcoming these carcinogenic side effects, or, alternatively, a basis for developing effective compounds for targeted phototherapy. In this review, a broad examination is undertaken, surveying the basic photochemical properties and excited-state dynamics of sulfur-substituted analogs of the canonical DNA and RNA nucleobases. A molecular-level understanding of how sulfur substitution so remarkably perturbs the photochemical properties of the nucleobases is presented by combining experimental results with quantum-chemical calculations. Structure-property relationships demonstrate the impact of site-specific sulfur substitution on the photochemical properties, particularly on the population of the reactive triplet state. The value of fundamental photochemical investigations for driving the development of ultraviolet-A chemotherapeutics is showcased. The most promising photodynamic agents identified thus far have been investigated in various carcinoma cell lines and shown to decrease cell proliferation upon exposure to ultraviolet-A radiation. Overarching principles have been elucidated for the impact that sulfur substitution of the carbonyl oxygen has on the photochemical properties of the nucleobases.
Collapse
Affiliation(s)
- Brennan Ashwood
- Department of Chemistry, Case Western Reserve University, Cleveland, OH
| | - Marvin Pollum
- Department of Chemistry, Case Western Reserve University, Cleveland, OH
| | | |
Collapse
|
12
|
Miyata S, Yamada T, Isozaki T, Sugimura H, Xu YZ, Suzuki T. Absorption Characteristics and Quantum Yields of Singlet Oxygen Generation of Thioguanosine Derivatives. Photochem Photobiol 2018; 94:677-684. [DOI: 10.1111/php.12900] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 01/17/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Shoma Miyata
- Department of Chemistry and Biological Science; Aoyama Gakuin University; Sagamihara Kanagawa Japan
| | - Takeshi Yamada
- Department of Chemistry and Biological Science; Aoyama Gakuin University; Sagamihara Kanagawa Japan
| | - Tasuku Isozaki
- Department of Chemistry and Biological Science; Aoyama Gakuin University; Sagamihara Kanagawa Japan
| | - Hideyuki Sugimura
- Department of Chemistry and Biological Science; Aoyama Gakuin University; Sagamihara Kanagawa Japan
| | - Yao-Zhong Xu
- School of Life, Health and Chemical Sciences; the Open University; Milton Keynes UK
| | - Tadashi Suzuki
- Department of Chemistry and Biological Science; Aoyama Gakuin University; Sagamihara Kanagawa Japan
| |
Collapse
|
13
|
UVA Irradiation Enhances Brusatol-Mediated Inhibition of Melanoma Growth by Downregulation of the Nrf2-Mediated Antioxidant Response. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:9742154. [PMID: 29670684 PMCID: PMC5835260 DOI: 10.1155/2018/9742154] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 11/09/2017] [Accepted: 11/27/2017] [Indexed: 12/30/2022]
Abstract
Brusatol (BR) is a potent inhibitor of Nrf2, a transcription factor that is highly expressed in cancer tissues and confers chemoresistance. UVA-generated reactive oxygen species (ROS) can damage both normal and cancer cells and may be of potential use in phototherapy. In order to provide an alternative method to treat the aggressive melanoma, we sought to investigate whether low-dose UVA with BR is more effective in eliminating melanoma cells than the respective single treatments. We found that BR combined with UVA led to inhibition of A375 melanoma cell proliferation by cell cycle arrest in the G1 phase and triggers cell apoptosis. Furthermore, inhibition of Nrf2 expression attenuated colony formation and tumor development from A375 cells in heterotopic mouse models. In addition, cotreatment of UVA and BR partially suppressed Nrf2 and its downstream target genes such as HO-1 along with the PI3K/AKT pathway. We propose that cotreatment increased ROS-induced cell cycle arrest and cellular apoptosis and inhibits melanoma growth by regulating the AKT-Nrf2 pathway in A375 cells which offers a possible therapeutic intervention strategy for the treatment of human melanoma.
Collapse
|
14
|
Sample A, He YY. Autophagy in UV Damage Response. Photochem Photobiol 2017; 93:943-955. [PMID: 27935061 PMCID: PMC5466513 DOI: 10.1111/php.12691] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 10/22/2016] [Indexed: 12/14/2022]
Abstract
UV radiation exposure from sunlight and artificial tanning beds is the major risk factor for the development of skin cancer and skin photoaging. UV-induced skin damage can trigger a cascade of DNA damage response signaling pathways, including cell cycle arrest, DNA repair and, if damage is irreparable, apoptosis. Compensatory proliferation replaces the apoptotic cells to maintain skin barrier integrity. Disruption of these processes can be exploited to promote carcinogenesis by allowing the survival and proliferation of damaged cells. UV radiation also induces autophagy, a catabolic process that clears unwanted or damaged proteins, lipids and organelles. The mechanisms by which autophagy is activated following UV exposure, and the functions of autophagy in UV response, are only now being clarified. Here, we summarize the current understanding of the mechanisms governing autophagy regulation by UV, the roles of autophagy in regulating cellular response to UV-induced photodamage and the implications of autophagy modulation in the treatment and prevention of photoaging and skin cancer.
Collapse
Affiliation(s)
- Ashley Sample
- Department of Medicine, Section of Dermatology, University of Chicago, Chicago, IL
- Committee on Cancer Biology, University of Chicago, Chicago, IL
| | - Yu-Ying He
- Department of Medicine, Section of Dermatology, University of Chicago, Chicago, IL
- Committee on Cancer Biology, University of Chicago, Chicago, IL
| |
Collapse
|
15
|
Zhang XH, Yin HY, Trigiante G, Brem R, Karran P, Pitak MB, Coles SJ, Xu YZ. 5-Iodo-4-thio-2′-deoxyuridine: Synthesis, Structure, and Cytotoxic Activity. CHEM LETT 2015. [DOI: 10.1246/cl.140965] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Xiao-Hui Zhang
- College of Environment and Chemical Engineering, Dalian University
| | - Hong-Yan Yin
- College of Environment and Chemical Engineering, Dalian University
| | | | - Reto Brem
- Cancer Research UK London Research Institute, Clare Hall Laboratories
| | - Peter Karran
- Cancer Research UK London Research Institute, Clare Hall Laboratories
| | - Mateusz B. Pitak
- UK National Crystallography Service, Chemistry, Faculty of Natural and Environmental Sciences, University of Southampton
| | - Simon J. Coles
- UK National Crystallography Service, Chemistry, Faculty of Natural and Environmental Sciences, University of Southampton
| | - Yao-Zhong Xu
- Department of Life, Health and Chemical Sciences, the Open University
| |
Collapse
|
16
|
Pollum M, Jockusch S, Crespo-Hernández CE. 2,4-Dithiothymine as a Potent UVA Chemotherapeutic Agent. J Am Chem Soc 2014; 136:17930-3. [DOI: 10.1021/ja510611j] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Marvin Pollum
- Department
of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Steffen Jockusch
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Carlos E. Crespo-Hernández
- Department
of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, Cleveland, Ohio 44106, United States
| |
Collapse
|
17
|
Zhang X, Zhai H, Gao R, Zhang J, Zhang Y, Zheng X. Study on the interaction between 4-thio-5-methyluridine and human serum albumin by spectroscopy and molecular modeling. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 121:724-731. [PMID: 24374886 DOI: 10.1016/j.saa.2013.11.113] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 11/24/2013] [Accepted: 11/26/2013] [Indexed: 06/03/2023]
Abstract
The interaction between 4-thio-5-methyluridine and human serum albumin (HSA) under simulative physiological conditions has been studied by the methods of fluorescence, UV-VIS absorbance and circular dichroism (CD) spectroscopy. The results show that 4-thio-5-methyluridine has a static fluorescence quenching on human serum albumin (HSA). The main forces of both interactions have typical static interaction from thermodynamic data to the determination. The experimental result was in correspondence with molecular modeling theory.
Collapse
Affiliation(s)
- Xiaohui Zhang
- College of Environment and Chemical Engineering, Dalian University, Dalian, Liaoning 116622, China.
| | - Hongxiu Zhai
- College of Environment and Chemical Engineering, Dalian University, Dalian, Liaoning 116622, China
| | - Ruiqi Gao
- College of Environment and Chemical Engineering, Dalian University, Dalian, Liaoning 116622, China
| | - Juling Zhang
- MOE Key laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong 510631, China
| | - Yue Zhang
- College of Environment and Chemical Engineering, Dalian University, Dalian, Liaoning 116622, China
| | - Xuefang Zheng
- College of Environment and Chemical Engineering, Dalian University, Dalian, Liaoning 116622, China
| |
Collapse
|
18
|
Chen YC, Huang SC, Wang YK, Liu YT, Wu TK, Chen TM. Ligand-functionalization of BPEI-coated YVO4:Bi3+,Eu3+ nanophosphors for tumor-cell-targeted imaging applications. Chem Asian J 2013; 8:2652-9. [PMID: 23894123 DOI: 10.1002/asia.201300570] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 05/22/2013] [Indexed: 01/06/2023]
Abstract
In this study, surface-functionalized, branched polyethylenimine (BPEI)-modified YVO4:Bi(3+),Eu(3+) nanocrystals (NCs) were successfully synthesized by a simple, rapid, solvent-free hydrothermal method. The BPEI-coated YVO4:Bi(3+),Eu(3+) NCs with high crystallinity show broad-band excitation in the λ=250 to 400 nm near-ultraviolet (NUV) region and exhibit a sharp-line emission band centered at λ=619 nm under excitation at λ=350 nm. The surface amino groups contributed by the capping agent, BPEI, not only improve the dispersibility and water/buffer stability of the BPEI-coated YVO4:Bi(3+),Eu(3+) NCs, but also provide a capability for specifically targeted biomolecule conjugation. Folic acid (FA) and epidermal growth factor (EGF) were further attached to the BPEI-coated YVO4:Bi(3+),Eu(3+) NCs and exhibited effective positioning of fluorescent NCs toward the targeted folate receptor overexpressed in HeLa cells or EGFR overexpressed in A431 cells with low cytotoxicity. These results demonstrate that the ligand-functionalized, BPEI-coated YVO4:Bi(3+),Eu(3+) NCs show great potential as a new-generation biological luminescent bioprobe for bioimaging applications. Moreover, the unique luminescence properties of BPEI-coated YVO4:Bi(3+),Eu(3+) NCs show potential to combine with a UVA photosensitizing drug to produce both detective and therapeutic effects for human skin cancer therapy.
Collapse
Affiliation(s)
- Yi-Chin Chen
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Science Building 2, 1001 Ta Hsueh Road, Hsinchu, 300 (Taiwan), Fax: (+886) 3-5723764
| | | | | | | | | | | |
Collapse
|
19
|
Cadet J, Mouret S, Ravanat JL, Douki T. Photoinduced damage to cellular DNA: direct and photosensitized reactions. Photochem Photobiol 2012; 88:1048-65. [PMID: 22780837 DOI: 10.1111/j.1751-1097.2012.01200.x] [Citation(s) in RCA: 209] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The survey focuses on recent aspects of photochemical reactions to cellular DNA that are implicated through the predominant formation of mostly bipyrimidine photoproducts in deleterious effects of human exposure to sunlight. Recent developments in analytical methods have allowed accurate and quantitative measurements of the main DNA photoproducts in cells and human skin. Highly mutagenic CC and CT bipyrimidine photoproducts, including cyclobutane pyrimidine dimers and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs) are generated in low yields with respect to TT and TC photoproducts. Another striking finding deals with the formation of Dewar valence isomers, the third class of bipyrimidine photoproducts that is accounted for by UVA-mediated isomerization of initially UVB generated 6-4PPs. Cyclobutadithymine (T<>T) has been unambiguously shown to be involved in the genotoxicity of UVA radiation. Thus, T<>T is formed in UVA-irradiated cellular DNA according to a direct excitation mechanism with a higher efficiency than oxidatively generated DNA damage that arises mostly through the Type II photosensitization mechanism. C<>C and C<>T are repaired at rates intermediate between those of T<>T and 6-4TT. Evidence has been also provided for the occurrence of photosensitized reactions mediated by exogenous agents that act either in an independent way or through photodynamic effects.
Collapse
Affiliation(s)
- Jean Cadet
- Laboratoire Lésions des Acides Nucléiques, SCIB-UMR-E n°3, CEA/UJF, Institut Nanosciences et Cryogénie, CEA/Grenoble, Grenoble Cedex, France
| | | | | | | |
Collapse
|
20
|
Reelfs O, Karran P, Young AR. 4-Thiothymidine sensitization of DNA to UVA offers potential for a novel photochemotherapy. Photochem Photobiol Sci 2012; 11:148-54. [PMID: 22044942 DOI: 10.1039/c1pp05188a] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 09/23/2011] [Indexed: 02/11/2024]
Abstract
Photochemotherapy, in which ultraviolet radiation (UVR: 280-400 nm) or visible light is combined with a photosensitizing drug to produce a therapeutic effect that neither drug or radiation can achieve alone, is a proven therapeutic strategy for a number of non-malignant hyperproliferative skin conditions and various cancers. Examples are psoralen plus UVA (320-400 nm) radiation (PUVA) and photodynamic therapy (PDT). All existing photochemotherapies have drawbacks - for example the association of PUVA with the development of skin cancer, and pain that is often associated with PDT treatment of skin lesions. There is a clear need to develop alternative approaches that involve lower radiation doses and/or improved selectivity for target cells. In this review, we explore the possibility to address this need by exploiting thionucleoside-mediated DNA photosensitisation to low, non toxic doses of UVA radiation.
Collapse
Affiliation(s)
- Olivier Reelfs
- King's College London, King's College London School of Medicine, Division of Genetics and Molecular Medicine, St John's Institute of Dermatology, London, UK SE19RT.
| | | | | |
Collapse
|
21
|
Reelfs O, Macpherson P, Ren X, Xu YZ, Karran P, Young AR. Identification of potentially cytotoxic lesions induced by UVA photoactivation of DNA 4-thiothymidine in human cells. Nucleic Acids Res 2011; 39:9620-32. [PMID: 21890905 PMCID: PMC3239200 DOI: 10.1093/nar/gkr674] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Revised: 07/28/2011] [Accepted: 07/31/2011] [Indexed: 11/24/2022] Open
Abstract
Photochemotherapy-in which a photosensitizing drug is combined with ultraviolet or visible radiation-has proven therapeutic effectiveness. Existing approaches have drawbacks, however, and there is a clinical need to develop alternatives offering improved target cell selectivity. DNA substitution by 4-thiothymidine (S(4)TdR) sensitizes cells to killing by ultraviolet A (UVA) radiation. Here, we demonstrate that UVA photoactivation of DNA S(4)TdR does not generate reactive oxygen or cause direct DNA breakage and is only minimally mutagenic. In an organotypic human skin model, UVA penetration is sufficiently robust to kill S(4)TdR-photosensitized epidermal cells. We have investigated the DNA lesions responsible for toxicity. Although thymidine is the predominant UVA photoproduct of S(4)TdR in dilute solution, more complex lesions are formed when S(4)TdR-containing oligonucleotides are irradiated. One of these, a thietane/S(5)-(6-4)T:T, is structurally related to the (6-4) pyrimidine:pyrimidone [(6-4) Py:Py] photoproducts induced by UVB/C radiation. These lesions are detectable in DNA from S(4)TdR/UVA-treated cells and are excised from DNA more efficiently by keratinocytes than by leukaemia cells. UVA irradiation also induces DNA interstrand crosslinking of S(4)TdR-containing duplex oligonucleotides. Cells defective in repairing (6-4) Py:Py DNA adducts or processing DNA crosslinks are extremely sensitive to S(4)TdR/UVA indicating that these lesions contribute significantly to S(4)TdR/UVA cytotoxicity.
Collapse
Affiliation(s)
- Olivier Reelfs
- King's College London, School of Medicine, Division of Genetics and Molecular Medicine, St John's Institute of Dermatology, London, SE1 9RT, UK.
| | | | | | | | | | | |
Collapse
|
22
|
Pridgeon SW, Heer R, Taylor GA, Newell DR, O'Toole K, Robinson M, Xu YZ, Karran P, Boddy AV. Thiothymidine combined with UVA as a potential novel therapy for bladder cancer. Br J Cancer 2011; 104:1869-76. [PMID: 21610703 PMCID: PMC3111209 DOI: 10.1038/bjc.2011.180] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 04/20/2011] [Accepted: 04/28/2011] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Thiothymidine (S(4)TdR) can be incorporated into DNA and sensitise cells to DNA damage and cell death following exposure to UVA light. Studies were performed to determine if the combination of S(4)TdR and UVA could be an effective treatment for bladder cancer. METHODS Uptake and incorporation of S(4)TdR was determined in rat and human bladder tumour cell lines. Measures of DNA crosslinking and apoptosis were also performed. In vivo activity of the combination of S(4)TdR and UVA was investigated in an orthotopic model of bladder cancer in rats. RESULTS Thiothymidine (200 μM) replaced up to 0.63% of thymidine in rat and tumour bladder cancer cells. The combination of S(4)TdR (10-200 μM) and UVA (1-5 kJ m(-2)) caused apoptosis and cell death at doses that were not toxic alone. Addition of raltitrexed (Astra Zeneca, Alderley Edge, Cheshire, UK) increased the incorporation of S(4)TdR into DNA (up to 20-fold at IC(5)) and further sensitised cells to UVA. Cytotoxic effect was associated with crosslinking of DNA, at least partially to protein. Intravenous administration of S(4)TdR, in combination with UVA delivered directly to the bladder, resulted in an antitumour effect in three of five animals treated. CONCLUSION These data indicate that the combination of S(4)TdR and UVA has potential as a treatment for bladder cancer, and give some insight into the mechanism of action. Further work is necessary to optimise the delivery of the two components.
Collapse
Affiliation(s)
- S W Pridgeon
- Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle NE2 4HH, UK
| | - R Heer
- Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle NE2 4HH, UK
- Department of Urology, Freeman Hospital, Newcastle, UK
| | - G A Taylor
- Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle NE2 4HH, UK
| | - D R Newell
- Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle NE2 4HH, UK
| | - K O'Toole
- Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle NE2 4HH, UK
| | - M Robinson
- Department of Histopathology, Royal Victoria Infirmary, Newcastle, UK
| | - Y-Z Xu
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, UK
| | - P Karran
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, UK
| | - A V Boddy
- Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle NE2 4HH, UK
| |
Collapse
|
23
|
Wenska G, Taras-Goślińska K, Łukaszewicz A, Burdziński G, Koput J, Maciejewski A. Mechanism and dynamics of intramolecular triplet state decay of 1-propyl-4-thiouracil and its α-methyl-substituted derivatives studied in perfluoro-1,3-dimethylcyclohexane. Photochem Photobiol Sci 2011; 10:1294-302. [PMID: 21594285 DOI: 10.1039/c1pp05034f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The absorption, phosphorescence and phosphorescence excitation spectra, phosphorescence quantum yields, and T(1) excited state lifetimes of four 4-thiouracil derivatives were measured for the first time in chemically inert and very weakly interacting perfluoro-1,3-dimethylcyclohexane at room temperature. The set of the 4-thiouracil derivatives comprises 1-propyl-4-thiouracil (PTU) and the related compounds having a methyl substituent at the position α to the thiocarbonyl group, namely 1-propyl-4-thiothymine (PTT), 1,3-dimethyl-4-thiouracil (DMTU), and 1-methyl-3-trideuteriomethyl-4-thiouracil ([D(3)]DMTU). Quantitative information on the intramolecular decay of the T(1) excited state of the four 4-thiouracil derivatives is presented, and the mechanism and dynamics of this process are discussed. In the absence of self quenching and solvent induced deactivation, the T(1) decay of the four 4-thiouracil derivatives was dominated by intramolecular nonradiative processes (NR). The values of the rate constant k(NR) in DMTU and [D(3)]DMTU are about 4 times larger than that in PTT and about 3 times larger than that in PTU. The reasons for the enhanced nonradiative rate constant in DMTU are discussed. It is concluded that the faster rate of the nonradiative processes in DMTU is related to a larger contribution from mixing of the T(2) (nπ*) state into the lowest energy T(1) (ππ*) state, as compared to the analogous coupling in PTU and PTT. This conclusion is supported by ab initio calculations performed at the EOM-CC2/aug-cc-pVDZ level of theory. The energy spacing between the T(2) (nπ*) and T(1) (ππ*) states is estimated to be about 500, 1100, and 2000 cm(-1) for DMTU, PTU, and PTT, respectively. Among the three compounds in question, the predicted energy spacing is thus the smallest for DMTU.
Collapse
Affiliation(s)
- Grazyna Wenska
- Faculty of Chemistry, Adam Mickiewicz University, 60-780, Poznan, Poland.
| | | | | | | | | | | |
Collapse
|
24
|
Li B, Chen Z, Liu L, Huang Z, Huang Z, Xie S. Differences in sensitivity to HMME-mediated photodynamic therapy between EBV+ C666-1 and EBV− CNE2 cells. Photodiagnosis Photodyn Ther 2010; 7:204-9. [DOI: 10.1016/j.pdpdt.2010.05.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 05/24/2010] [Accepted: 05/25/2010] [Indexed: 11/30/2022]
|
25
|
Patro BS, Maity B, Chattopadhyay S. Topoisomerase inhibitor coralyne photosensitizes DNA, leading to elicitation of Chk2-dependent S-phase checkpoint and p53-independent apoptosis in cancer cells. Antioxid Redox Signal 2010; 12:945-60. [PMID: 19922265 DOI: 10.1089/ars.2009.2508] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The possibility of synergism between the topoisomerase inhibition by coralyne and its DNA photonicking properties being used to kill cancer cells was explored. Compared with coralyne alone, the CUVA treatment dramatically enhanced DNA damage and apoptosis in cells. Despite causing an increased p53 expression, the CUVA treatment led to p53-independent apoptosis, causing almost similar cell death in wild-type, p53 mutant, and p53-silenced tumor cells. Expression of the p53-regulated downstream proteins like p21, and DNA-damage-dependent p53 phosphorylation at serine-15 residue also was not elicited by the CUVA treatment, at a low coralyne concentration. Instead, it led to an immediate activation of the Chk2-mediated S-phase arrest, despite activating PARP protein for DNA repair. The S-phase arrest subsequently ensures apoptosis through activation of caspases-3 and -9, the latter being reflected from the results with a specific caspase-9 inhibitor. Abrogation of Chk2 activity by shRNA or by using ATM-specific inhibitor (ATMi) led to a defective S-phase checkpoint and further augmentation in apoptosis. However, at a high coralyne concentration, the CUVA-induced apoptosis followed multiple and independent pathways, involving several caspases. The CUVA treatment may represent a novel mechanism-based protocol for increasing the efficacy of coralyne in inducing apoptosis in both p53 wild-type and mutant tumor cells.
Collapse
|