1
|
Qian J, Cartee A, Xu W, Yan Y, Wang B, Artsimovitch I, Dunlap D, Finzi L. Reciprocating RNA Polymerase batters through roadblocks. Nat Commun 2024; 15:3193. [PMID: 38609371 PMCID: PMC11014978 DOI: 10.1038/s41467-024-47531-x] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 04/04/2024] [Indexed: 04/14/2024] Open
Abstract
RNA polymerases must transit through protein roadblocks to produce full-length transcripts. Here we report real-time measurements of Escherichia coli RNA polymerase passing through different barriers. As intuitively expected, assisting forces facilitated, and opposing forces hindered, RNA polymerase passage through lac repressor protein bound to natural binding sites. Force-dependent differences were significant at magnitudes as low as 0.2 pN and were abolished in the presence of the transcript cleavage factor GreA, which rescues backtracked RNA polymerase. In stark contrast, opposing forces promoted passage when the rate of RNA polymerase backtracking was comparable to, or faster than the rate of dissociation of the roadblock, particularly in the presence of GreA. Our experiments and simulations indicate that RNA polymerase may transit after roadblocks dissociate, or undergo cycles of backtracking, recovery, and ramming into roadblocks to pass through. We propose that such reciprocating motion also enables RNA polymerase to break protein-DNA contacts that hold RNA polymerase back during promoter escape and RNA chain elongation. This may facilitate productive transcription in vivo.
Collapse
Affiliation(s)
- Jin Qian
- Physics Department, Emory University, Atlanta, GA, USA
| | | | - Wenxuan Xu
- Physics Department, Emory University, Atlanta, GA, USA
| | - Yan Yan
- Physics Department, Emory University, Atlanta, GA, USA
| | - Bing Wang
- The Center for RNA Biology and Department of Microbiology, The Ohio State University, Columbus, OH, USA
| | - Irina Artsimovitch
- The Center for RNA Biology and Department of Microbiology, The Ohio State University, Columbus, OH, USA
| | - David Dunlap
- Physics Department, Emory University, Atlanta, GA, USA
| | - Laura Finzi
- Physics Department, Emory University, Atlanta, GA, USA.
| |
Collapse
|
2
|
Liatsou I, Fu Y, Li Z, Hasan M, Guo X, Yu J, Piccolo J, Cartee A, Wang H, Du Y, Bryan J, Gabrielson K, Kraitchman DL, Sgouros G. Therapeutic efficacy of an alpha-particle emitter labeled anti-GD2 humanized antibody against osteosarcoma-a proof of concept study. Eur J Nucl Med Mol Imaging 2024; 51:1409-1420. [PMID: 38108831 DOI: 10.1007/s00259-023-06528-2] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 11/14/2023] [Indexed: 12/19/2023]
Abstract
PURPOSE Current treatments for osteosarcoma (OS) have a poor prognosis, particularly for patients with metastasis and recurrence, underscoring an urgent need for new targeted therapies to improve survival. Targeted alpha-particle therapy selectively delivers cytotoxic payloads to tumors with radiolabeled molecules that recognize tumor-associated antigens. We have recently demonstrated the potential of an FDA approved, humanized anti-GD2 antibody, hu3F8, as a targeted delivery vector for radiopharmaceutical imaging of OS. The current study aims to advance this system for alpha-particle therapy of OS. METHODS The hu3F8 antibody was radiolabeled with actinium-225, and the safety and therapeutic efficacy of the [225Ac]Ac-DOTA-hu3F8 were evaluated in both orthotopic murine xenografts of OS and spontaneously occurring OS in canines. RESULTS Significant antitumor activity was proven in both cases, leading to improved overall survival. In the murine xenograft's case, tumor growth was delayed by 16-18 days compared to the untreated cohort as demonstrated by bioluminescence imaging. The results were further validated with magnetic resonance imaging at 33 days after treatment, and microcomputed tomography and planar microradiography post-mortem. Histological evaluations revealed radiation-induced renal toxicity, manifested as epithelial cell karyomegaly and suggestive polyploidy in the kidneys, suggesting rapid recovery of renal function after radiation damage. Treatment of the two canine patients delayed the progression of metastatic spread, with an overall survival time of 211 and 437 days and survival beyond documented metastasis of 111 and 84 days, respectively. CONCLUSION This study highlights the potential of hu3F8-based alpha-particle therapy as a promising treatment strategy for OS.
Collapse
Affiliation(s)
- Ioanna Liatsou
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Yingli Fu
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zhi Li
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mahmud Hasan
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xin Guo
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jing Yu
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Joseph Piccolo
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Allison Cartee
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hao Wang
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yong Du
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jeffrey Bryan
- Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, MO, USA
| | - Kathleen Gabrielson
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dara L Kraitchman
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - George Sgouros
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| |
Collapse
|