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Paul Chowdhuri S, Das BB. TDP1 phosphorylation by CDK1 in mitosis promotes MUS81-dependent repair of trapped Top1-DNA covalent complexes. EMBO J 2024:10.1038/s44318-024-00169-3. [PMID: 39014228 DOI: 10.1038/s44318-024-00169-3] [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: 11/15/2023] [Revised: 06/26/2024] [Accepted: 06/28/2024] [Indexed: 07/18/2024] Open
Abstract
Topoisomerase 1 (Top1) controls DNA topology, relieves DNA supercoiling during replication and transcription, and is critical for mitotic progression to the G1 phase. Tyrosyl-DNA phosphodiesterase 1 (TDP1) mediates the removal of trapped Top1-DNA covalent complexes (Top1cc). Here, we identify CDK1-dependent phosphorylation of TDP1 at residue S61 during mitosis. A TDP1 variant defective for S61 phosphorylation (TDP1-S61A) is trapped on the mitotic chromosomes, triggering DNA damage and mitotic defects. Moreover, we show that Top1cc repair in mitosis occurs via a MUS81-dependent DNA repair mechanism. Replication stress induced by camptothecin or aphidicolin leads to TDP1-S61A enrichment at common fragile sites, which over-stimulates MUS81-dependent chromatid breaks, anaphase bridges, and micronuclei, ultimately culminating in the formation of 53BP1 nuclear bodies during G1 phase. Our findings provide new insights into the cell cycle-dependent regulation of TDP1 dynamics for the repair of trapped Top1-DNA covalent complexes during mitosis that prevents genomic instability following replication stress.
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Affiliation(s)
- Srijita Paul Chowdhuri
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal, 700032, India
| | - Benu Brata Das
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal, 700032, India.
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2
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Muñoz S, Barroso S, Badra-Fajardo N, Marqueta-Gracia JJ, García-Rubio ML, Ubieto-Capella P, Méndez J, Aguilera A. SIN3A histone deacetylase action counteracts MUS81 to promote stalled fork stability. Cell Rep 2024; 43:113778. [PMID: 38341854 PMCID: PMC10915396 DOI: 10.1016/j.celrep.2024.113778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 12/09/2023] [Accepted: 01/26/2024] [Indexed: 02/13/2024] Open
Abstract
During genome duplication, replication forks (RFs) can be stalled by different obstacles or by depletion of replication factors or nucleotides. A limited number of histone post-translational modifications at stalled RFs are involved in RF protection and restart. Provided the recent observation that the SIN3A histone deacetylase complex reduces transcription-replication conflicts, we explore the role of the SIN3A complex in protecting RFs under stressed conditions. We observe that Sin3A protein is enriched at replicating DNA in the presence of hydroxyurea. In this situation, Sin3A-depleted cells show increased RF stalling, H3 acetylation, and DNA breaks at stalled RFs. Under Sin3A depletion, RF recovery is impaired, and DNA damage accumulates. Importantly, these effects are partially dependent on the MUS81 endonuclease, which promotes DNA breaks and MRE11-dependent DNA degradation of such breaks. We propose that chromatin deacetylation triggered by the SIN3A complex limits MUS81 cleavage of stalled RFs, promoting genome stability when DNA replication is challenged.
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Affiliation(s)
- Sergio Muñoz
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Sonia Barroso
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Nibal Badra-Fajardo
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - José Javier Marqueta-Gracia
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - María L García-Rubio
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Patricia Ubieto-Capella
- Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain
| | - Juan Méndez
- Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain.
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3
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Zhao Y, Hou K, Li Y, Hao S, Liu Y, Na Y, Li C, Cui J, Xu X, Wu X, Wang H. Human HELQ regulates DNA end resection at DNA double-strand breaks and stalled replication forks. Nucleic Acids Res 2023; 51:12207-12223. [PMID: 37897354 PMCID: PMC10711563 DOI: 10.1093/nar/gkad940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/15/2023] [Accepted: 10/11/2023] [Indexed: 10/30/2023] Open
Abstract
Following a DNA double strand break (DSB), several nucleases and helicases coordinate to generate single-stranded DNA (ssDNA) with 3' free ends, facilitating precise DNA repair by homologous recombination (HR). The same nucleases can act on stalled replication forks, promoting nascent DNA degradation and fork instability. Interestingly, some HR factors, such as CtIP and BRCA1, have opposite regulatory effects on the two processes, promoting end resection at DSB but inhibiting the degradation of nascent DNA on stalled forks. However, the reason why nuclease actions are regulated by different mechanisms in two DNA metabolism is poorly understood. We show that human HELQ acts as a DNA end resection regulator, with opposing activities on DNA end resection at DSBs and on stalled forks as seen for other regulators. Mechanistically, HELQ helicase activity is required for EXO1-mediated DSB end resection, while ssDNA-binding capacity of HELQ is required for its recruitment to stalled forks, facilitating fork protection and preventing chromosome aberrations caused by replication stress. Here, HELQ synergizes with CtIP but not BRCA1 or BRCA2 to protect stalled forks. These findings reveal an unanticipated role of HELQ in regulating DNA end resection at DSB and stalled forks, which is important for maintaining genome stability.
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Affiliation(s)
- Yuqin Zhao
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Kaiping Hou
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Youhang Li
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Shuailin Hao
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Yu Liu
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Yinan Na
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Chao Li
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Jian Cui
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Xingzhi Xu
- Guangdong Key Laboratory for Genome Stability & Disease Prevention and Carson International Cancer Center, Marshall Laboratory of Biomedical Engineering, China Shenzhen University School of Medicine, Shenzhen, Guangdong 518060, China
| | - Xiaohua Wu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Hailong Wang
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
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Mladenov E, Mladenova V, Stuschke M, Iliakis G. New Facets of DNA Double Strand Break Repair: Radiation Dose as Key Determinant of HR versus c-NHEJ Engagement. Int J Mol Sci 2023; 24:14956. [PMID: 37834403 PMCID: PMC10573367 DOI: 10.3390/ijms241914956] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/01/2023] [Accepted: 10/03/2023] [Indexed: 10/15/2023] Open
Abstract
Radiation therapy is an essential component of present-day cancer management, utilizing ionizing radiation (IR) of different modalities to mitigate cancer progression. IR functions by generating ionizations in cells that induce a plethora of DNA lesions. The most detrimental among them are the DNA double strand breaks (DSBs). In the course of evolution, cells of higher eukaryotes have evolved four major DSB repair pathways: classical non-homologous end joining (c-NHEJ), homologous recombination (HR), alternative end-joining (alt-EJ), and single strand annealing (SSA). These mechanistically distinct repair pathways have different cell cycle- and homology-dependencies but, surprisingly, they operate with widely different fidelity and kinetics and therefore contribute unequally to cell survival and genome maintenance. It is therefore reasonable to anticipate tight regulation and coordination in the engagement of these DSB repair pathway to achieve the maximum possible genomic stability. Here, we provide a state-of-the-art review of the accumulated knowledge on the molecular mechanisms underpinning these repair pathways, with emphasis on c-NHEJ and HR. We discuss factors and processes that have recently come to the fore. We outline mechanisms steering DSB repair pathway choice throughout the cell cycle, and highlight the critical role of DNA end resection in this process. Most importantly, however, we point out the strong preference for HR at low DSB loads, and thus low IR doses, for cells irradiated in the G2-phase of the cell cycle. We further explore the molecular underpinnings of transitions from high fidelity to low fidelity error-prone repair pathways and analyze the coordination and consequences of this transition on cell viability and genomic stability. Finally, we elaborate on how these advances may help in the development of improved cancer treatment protocols in radiation therapy.
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Affiliation(s)
- Emil Mladenov
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany; (V.M.); (M.S.)
- Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany
| | - Veronika Mladenova
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany; (V.M.); (M.S.)
- Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany
| | - Martin Stuschke
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany; (V.M.); (M.S.)
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, 45147 Essen, Germany
- German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - George Iliakis
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany; (V.M.); (M.S.)
- Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany
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5
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Sachsenweger J, Jansche R, Merk T, Heitmeir B, Deniz M, Faust U, Roggia C, Tzschach A, Schroeder C, Riess A, Pospiech H, Peltoketo H, Pylkäs K, Winqvist R, Wiesmüller L. ABRAXAS1 orchestrates BRCA1 activities to counter genome destabilizing repair pathways-lessons from breast cancer patients. Cell Death Dis 2023; 14:328. [PMID: 37198153 DOI: 10.1038/s41419-023-05845-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 04/27/2023] [Accepted: 05/02/2023] [Indexed: 05/19/2023]
Abstract
It has been well-established that mutations in BRCA1 and BRCA2, compromising functions in DNA double-strand break repair (DSBR), confer hereditary breast and ovarian cancer risk. Importantly, mutations in these genes explain only a minor fraction of the hereditary risk and of the subset of DSBR deficient tumors. Our screening efforts identified two truncating germline mutations in the gene encoding the BRCA1 complex partner ABRAXAS1 in German early-onset breast cancer patients. To unravel the molecular mechanisms triggering carcinogenesis in these carriers of heterozygous mutations, we examined DSBR functions in patient-derived lymphoblastoid cells (LCLs) and in genetically manipulated mammary epithelial cells. By use of these strategies we were able to demonstrate that these truncating ABRAXAS1 mutations exerted dominant effects on BRCA1 functions. Interestingly, we did not observe haploinsufficiency regarding homologous recombination (HR) proficiency (reporter assay, RAD51-foci, PARP-inhibitor sensitivity) in mutation carriers. However, the balance was shifted to use of mutagenic DSBR-pathways. The dominant effect of truncated ABRAXAS1 devoid of the C-terminal BRCA1 binding site can be explained by retention of the N-terminal interaction sites for other BRCA1-A complex partners like RAP80. In this case BRCA1 was channeled from the BRCA1-A to the BRCA1-C complex, which induced single-strand annealing (SSA). Further truncation, additionally deleting the coiled-coil region of ABRAXAS1, unleashed excessive DNA damage responses (DDRs) de-repressing multiple DSBR-pathways including SSA and non-homologous end-joining (NHEJ). Our data reveal de-repression of low-fidelity repair activities as a common feature of cells from patients with heterozygous mutations in genes encoding BRCA1 and its complex partners.
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Affiliation(s)
- Juliane Sachsenweger
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
- Laboratory of Cancer Genetics and Tumor Biology, Translational Medicine Research Unit, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Rebecca Jansche
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Tatjana Merk
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Benedikt Heitmeir
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Miriam Deniz
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Ulrike Faust
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Cristiana Roggia
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Andreas Tzschach
- Institute of Human Genetics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christopher Schroeder
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Angelika Riess
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Helmut Pospiech
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Hellevi Peltoketo
- Laboratory of Cancer Genetics and Tumor Biology, Translational Medicine Research Unit, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Katri Pylkäs
- Laboratory of Cancer Genetics and Tumor Biology, Translational Medicine Research Unit, Biocenter Oulu, University of Oulu, Oulu, Finland
- Laboratory of Cancer Genetics and Tumor Biology, Northern Finland Laboratory Centre, Oulu, Finland
| | - Robert Winqvist
- Laboratory of Cancer Genetics and Tumor Biology, Translational Medicine Research Unit, Biocenter Oulu, University of Oulu, Oulu, Finland
- Laboratory of Cancer Genetics and Tumor Biology, Northern Finland Laboratory Centre, Oulu, Finland
| | - Lisa Wiesmüller
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany.
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TDP1-independent pathways in the process and repair of TOP1-induced DNA damage. Nat Commun 2022; 13:4240. [PMID: 35869071 PMCID: PMC9307636 DOI: 10.1038/s41467-022-31801-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 06/29/2022] [Indexed: 11/15/2022] Open
Abstract
Anticancer drugs, such as camptothecin (CPT), trap topoisomerase I (TOP1) on DNA and form TOP1 cleavage complexes (TOP1cc). Alternative repair pathways have been suggested in the repair of TOP1cc. However, how these pathways work with TDP1, a key repair enzyme that specifically hydrolyze the covalent bond between TOP1 catalytic tyrosine and the 3’-end of DNA and contribute to the repair of TOP1cc is poorly understood. Here, using unbiased whole-genome CRISPR screens and generation of co-deficient cells with TDP1 and other genes, we demonstrate that MUS81 is an important factor that mediates the generation of excess double-strand breaks (DSBs) in TDP1 KO cells. APEX1/2 are synthetic lethal with TDP1. However, deficiency of APEX1/2 does not reduce DSB formation in TDP1 KO cells. Together, our data suggest that TOP1cc can be either resolved directly by TDP1 or be converted into DSBs and repaired further by the Homologous Recombination (HR) pathway. Here the authors find that MUS81 mediates excess DNA double strand break (DSB) generation in TDP1 KO cells after camptothecin treatment. They show that TOP1 cleavage complexes can be either resolved directly by TDP1 or be converted into DSBs and repaired further by the Homologous Recombination pathway.
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Foo TK, Xia B. BRCA1-Dependent and Independent Recruitment of PALB2-BRCA2-RAD51 in the DNA Damage Response and Cancer. Cancer Res 2022; 82:3191-3197. [PMID: 35819255 PMCID: PMC9481714 DOI: 10.1158/0008-5472.can-22-1535] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/22/2022] [Accepted: 07/08/2022] [Indexed: 11/16/2022]
Abstract
The BRCA1-PALB2-BRCA2 axis plays essential roles in the cellular response to DNA double-strand breaks (DSB), maintenance of genome integrity, and suppression of cancer development. Upon DNA damage, BRCA1 is recruited to DSBs, where it facilitates end resection and recruits PALB2 and its associated BRCA2 to load the central recombination enzyme RAD51 to initiate homologous recombination (HR) repair. In recent years, several BRCA1-independent mechanisms of PALB2 recruitment have also been reported. Collectively, these available data illustrate a series of hierarchical, context-dependent, and cooperating mechanisms of PALB2 recruitment that is critical for HR and therapy response either in the presence or absence of BRCA1. Here, we review these BRCA1-dependent and independent mechanisms and their importance in DSB repair, cancer development, and therapy. As BRCA1-mutant cancer cells regain HR function, for which PALB2 is generally required, and become resistant to targeted therapies, such as PARP inhibitors, targeting BRCA1-independent mechanisms of PALB2 recruitment represents a potential new avenue to improve treatment of BRCA1-mutant tumors.
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Affiliation(s)
- Tzeh Keong Foo
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey and Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
| | - Bing Xia
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey and Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
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Kim SM, Forsburg SL. Determinants of RPA megafoci localization to the nuclear periphery in response to replication stress. G3 (BETHESDA, MD.) 2022; 12:jkac116. [PMID: 35567482 PMCID: PMC9258583 DOI: 10.1093/g3journal/jkac116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/04/2022] [Indexed: 06/15/2023]
Abstract
Upon replication stress, ssDNA, coated by the ssDNA-binding protein RPA, accumulates and generates a signal to activate the replication stress response. Severe replication stress induced by the loss of minichromosome maintenance helicase subunit Mcm4 in the temperature-sensitive Schizosaccharomyces pombe degron mutant (mcm4-dg) results in the formation of a large RPA focus that is translocated to the nuclear periphery. We show that resection and repair processes and chromatin remodeler Swr1/Ino80 are involved in the large RPA foci formation and its relocalization to nuclear periphery. This concentrated accumulation of RPA increases the recruitment of Cds1 to chromatin and results in an aberrant cell cycle that lacks MBF-mediated G1/S accumulation of Tos4. These findings reveal a distinct replication stress response mediated by localized accumulation of RPA that allows the evasion of cell cycle arrest.
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Affiliation(s)
- Seong Min Kim
- Molecular & Computational Biology, University of Southern California, Los Angeles, CA 90007, USA
| | - Susan L Forsburg
- Corresponding author: Molecular & Computational Biology, University of Southern California, Los Angeles, CA 90007, USA.
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Constructing nanocomplexes by multicomponent self-assembly for curing orthotopic glioblastoma with synergistic chemo-photothermal therapy. Biomaterials 2021; 279:121193. [PMID: 34700227 DOI: 10.1016/j.biomaterials.2021.121193] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 12/18/2022]
Abstract
The blood-brain barrier (BBB) is one of the major limitations of glioblastoma therapy in the clinic. Nanodrugs have shown great potential for glioblastoma therapy. Herein, we purposefully developed a multicomponent self-assembly nanocomplex with very high drug loading content for curing orthotopic glioblastoma with synergistic chemo-photothermal therapy. The nanocomplex consisted of self-assembled pH-responsive nanodrugs derived from amino acid-conjugated camptothecin (CPT) and canine dyes (IR783) coated with peptide Angiopep-2-conjugated copolymer of Ang-PEG-g-PLL. Specifically, the carrier-free nanocomplex exhibited a high drug loading content (up to 62%), good biocompatibility, and effective glioma accumulation ability. Moreover, the nanocomplex displayed good stability and pH-responsive behavior ex vivo. Both in vitro and in vivo results revealed that the nanocomplex could effectively cross the BBB and target glioma cells. Furthermore, the combination of chemotherapy and photothermal therapy of the nanocomplex achieved a better therapeutic effect, longer survival time, and minimized toxic side effects in orthotopic glioblastoma tumor-bearing nude mice. Overall, we modified the chemotherapeutic drug CPT so that it could self-assemble with other molecules into nanoparticles, which providing an alternative for the preparation of the carrier-free nanodrugs. The results highlighted the potential of self-assembly nanodrugs as a novel platform for effective glioblastoma therapy.
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