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Loftis AR, Santos MS, Truex NL, Biancucci M, Satchell KJF, Pentelute BL. Anthrax Protective Antigen Retargeted with Single-Chain Variable Fragments Delivers Enzymes to Pancreatic Cancer Cells. Chembiochem 2020; 21:2772-2776. [PMID: 32369652 PMCID: PMC7541672 DOI: 10.1002/cbic.202000201] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [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: 03/31/2020] [Revised: 05/01/2020] [Indexed: 12/15/2022]
Abstract
The nontoxic, anthrax protective antigen/lethal factor N-terminal domain (PA/LFN ) complex is an effective platform for translocating proteins into the cytosol of cells. Mutant PA (mPA) was recently fused to epidermal growth factor (EGF) to retarget delivery of LFN to cells bearing EGF receptors (EGFR), but the requirement for a known cognate ligand limits the applicability of this approach. Here, we render practical protective antigen retargeting to a variety of receptors with mPA single-chain variable fragment (scFv) fusion constructs. Our design enables the targeting of two pancreatic cancer-relevant receptors, EGFR and carcinoembryonic antigen. We demonstrate that fusion to scFvs does not disturb the basic functions of mPA. Moreover, mPA-scFv fusions enable cell-specific delivery of diphtheria toxin catalytic domain and Ras/Rap1-specific endopeptidase to pancreatic cancer cells. Importantly, mPA-scFv fusion-based treatments display potent cell-specific toxicity in vitro, opening fundamentally new routes toward engineered immunotoxins and providing a potential solution to the challenge of targeted protein delivery to the cytosol of cancer cells.
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Affiliation(s)
- Alexander R Loftis
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Michael S Santos
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Nicholas L Truex
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Marco Biancucci
- Department of Microbiology-Immunology Feinberg School of Medicine, Northwestern University, 420 E Superior Street, Chicago, IL 60611, USA
| | - Karla J F Satchell
- Department of Microbiology-Immunology Feinberg School of Medicine, Northwestern University, 420 E Superior Street, Chicago, IL 60611, USA
| | - Bradley L Pentelute
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- The Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02142, USA
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA
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Lu Z, Paolella BR, Truex NL, Loftis AR, Liao X, Rabideau AE, Brown MS, Busanovich J, Beroukhim R, Pentelute BL. Targeting Cancer Gene Dependencies with Anthrax-Mediated Delivery of Peptide Nucleic Acids. ACS Chem Biol 2020; 15:1358-1369. [PMID: 32348107 PMCID: PMC7521945 DOI: 10.1021/acschembio.9b01027] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Antisense oligonucleotide therapies are important cancer treatments, which can suppress genes in cancer cells that are critical for cell survival. SF3B1 has recently emerged as a promising gene target that encodes a key splicing factor in the SF3B protein complex. Over 10% of cancers have lost one or more copies of the SF3B1 gene, rendering these cancers vulnerable after further suppression. SF3B1 is just one example of a CYCLOPS (Copy-number alterations Yielding Cancer Liabilities Owing to Partial losS) gene, but over 120 additional candidate CYCLOPS genes are known. Antisense oligonucleotide therapies for cancer offer the promise of effective suppression for CYCLOPS genes, but developing these treatments is difficult due to their limited permeability into cells and poor cytosolic stability. Here, we develop an effective approach to suppress CYCLOPS genes by delivering antisense peptide nucleic acids (PNAs) into the cytosol of cancer cells. We achieve efficient cytosolic PNA delivery with the two main nontoxic components of the anthrax toxin: protective antigen (PA) and the 263-residue N-terminal domain of lethal factor (LFN). Sortase-mediated ligation readily enables the conjugation of PNAs to the C terminus of the LFN protein. LFN and PA work together in concert to translocate PNAs into the cytosol of mammalian cells. Antisense SF3B1 PNAs delivered with the LFN/PA system suppress the SF3B1 gene and decrease cell viability, particularly of cancer cells with partial copy-number loss of SF3B1. Moreover, antisense SF3B1 PNAs delivered with a HER2-binding PA variant selectively target cancer cells that overexpress the HER2 cell receptor, demonstrating receptor-specific targeting of cancer cells. Taken together, our efforts illustrate how PA-mediated delivery of PNAs provides an effective and general approach for delivering antisense PNA therapeutics and for targeting gene dependencies in cancer.
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Affiliation(s)
- Zeyu Lu
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Brenton R. Paolella
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02139, USA
| | - Nicholas L. Truex
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Alexander R. Loftis
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Xiaoli Liao
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Amy E. Rabideau
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Meredith S. Brown
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02139, USA
| | - John Busanovich
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02139, USA
| | - Rameen Beroukhim
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02139, USA
| | - Bradley L. Pentelute
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
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Dhanjee HH, Saebi A, Buslov I, Loftis AR, Buchwald SL, Pentelute BL. Protein-Protein Cross-Coupling via Palladium-Protein Oxidative Addition Complexes from Cysteine Residues. J Am Chem Soc 2020; 142:9124-9129. [PMID: 32364380 DOI: 10.1021/jacs.0c03143] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Few chemical methods exist for the covalent conjugation of two proteins. We report the preparation of site-specific protein-protein conjugates that arise from the sequential cross-coupling of cysteine residues on two different proteins. The method involves the synthesis of stable palladium-protein oxidative addition complexes (Pd-protein OACs), a process that converts nucleophilic cysteine residues into an electrophilic S-aryl-Pd-X unit by taking advantage of an intramolecular oxidative addition strategy. This process is demonstrated on proteins up to 83 kDa in size and can be conveniently carried out in water and open to air. The resulting Pd-protein OACs can cross-couple with other thiol-containing proteins to arrive at homogeneous protein-protein bioconjugates.
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Affiliation(s)
- Heemal H Dhanjee
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Azin Saebi
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Ivan Buslov
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Alexander R Loftis
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Stephen L Buchwald
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Bradley L Pentelute
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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Mandala VS, Loftis AR, Shcherbakov AA, Pentelute BL, Hong M. Atomic structures of closed and open influenza B M2 proton channel reveal the conduction mechanism. Nat Struct Mol Biol 2020; 27:160-167. [PMID: 32015551 PMCID: PMC7641042 DOI: 10.1038/s41594-019-0371-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 12/30/2019] [Indexed: 12/13/2022]
Abstract
The influenza B M2 (BM2) proton channel is activated by acidic pH to mediate virus uncoating. Unlike influenza A M2 (AM2), which conducts protons with strong inward rectification, BM2 conducts protons both inward and outward. Here we report 1.4- and 1.5-Å solid-state NMR structures of the transmembrane domain of the closed and open BM2 channels in a phospholipid environment. Upon activation, the transmembrane helices increase the tilt angle by 6° and the average pore diameter enlarges by 2.1 Å. BM2 thus undergoes a scissor motion for activation, which differs from the alternating-access motion of AM2. These results indicate that asymmetric proton conduction requires a backbone hinge motion, whereas bidirectional conduction is achieved by a symmetric scissor motion. The proton-selective histidine and gating tryptophan in the open BM2 reorient on the microsecond timescale, similar to AM2, indicating that side chain dynamics are the essential driver of proton shuttling.
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Affiliation(s)
- Venkata S Mandala
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Alexander R Loftis
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Bradley L Pentelute
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.
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Jack S, Madhivanan K, Ramadesikan S, Subramanian S, Edwards DF, Elzey BD, Dhawan D, McCluskey A, Kischuk EM, Loftis AR, Truex N, Santos M, Lu M, Rabideau A, Pentelute B, Collier J, Kaimakliotis H, Koch M, Ratliff TL, Knapp DW, Aguilar RC. A novel, safe, fast and efficient treatment for Her2-positive and negative bladder cancer utilizing an EGF-anthrax toxin chimera. Int J Cancer 2019; 146:449-460. [PMID: 31584195 DOI: 10.1002/ijc.32719] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 08/10/2019] [Accepted: 09/11/2019] [Indexed: 12/20/2022]
Abstract
Bladder cancer is the sixth most common cancer in the United States, and it exhibits an alarming 70% recurrence rate. Thus, the development of more efficient antibladder cancer approaches is a high priority. Accordingly, this work provides the basis for a transformative anticancer strategy that takes advantage of the unique characteristics of the bladder. Unlike mucin-shielded normal bladder cells, cancer cells are exposed to the bladder lumen and overexpress EGFR. Therefore, we used an EGF-conjugated anthrax toxin that after targeting EGFR was internalized and triggered apoptosis in exposed bladder cancer cells. This unique agent presented advantages over other EGF-based technologies and other toxin-derivatives. In contrast to known agents, this EGF-toxin conjugate promoted its own uptake via receptor microclustering even in the presence of Her2 and induced cell death with a LC50 < 1 nM. Furthermore, our data showed that exposures as short as ≈3 min were enough to commit human (T24), mouse (MB49) and canine (primary) bladder cancer cells to apoptosis. Exposure of tumor-free mice and dogs with the agent resulted in no toxicity. In addition, the EGF-toxin was able to eliminate cells from human patient tumor samples. Importantly, the administration of EGF-toxin to dogs with spontaneous bladder cancer, who had failed or were not eligible for other therapies, resulted in ~30% average tumor reduction after one treatment cycle. Because of its in vitro and in vivo high efficiency, fast action (reducing treatment time from hours to minutes) and safety, we propose that this EGF-anthrax toxin conjugate provides the basis for new, transformative approaches against bladder cancer.
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Affiliation(s)
- Sherwin Jack
- Purdue University Center for Cancer Research, West Lafayette, IN.,Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Kayalvizhi Madhivanan
- Purdue University Center for Cancer Research, West Lafayette, IN.,Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Swetha Ramadesikan
- Purdue University Center for Cancer Research, West Lafayette, IN.,Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Sneha Subramanian
- Purdue University Center for Cancer Research, West Lafayette, IN.,Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Daniel F Edwards
- Purdue University Center for Cancer Research, West Lafayette, IN.,Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Bennett D Elzey
- Purdue University Center for Cancer Research, West Lafayette, IN.,Department of Comparative Pathobiology, Purdue University, West Lafayette, IN.,Department of Urology, Indiana University School of Medicine, Indianapolis, IN
| | - Deepika Dhawan
- Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN
| | | | - Erin M Kischuk
- Purdue University Center for Cancer Research, West Lafayette, IN.,Department of Comparative Pathobiology, Purdue University, West Lafayette, IN
| | - Alexander R Loftis
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA
| | - Nicholas Truex
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA
| | - Michael Santos
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA
| | - Mike Lu
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA
| | - Amy Rabideau
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA
| | - Bradley Pentelute
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA.,Koch Institute MIT, Cambridge, MA.,Broad Institute of Harvard and MIT, Cambridge, MA.,Center for Environmental Health Sciences MIT, Cambridge, MA
| | - John Collier
- Department of Microbiology, Harvard Medical School, Boston, MA
| | | | - Michael Koch
- Department of Urology, Indiana University School of Medicine, Indianapolis, IN
| | - Timothy L Ratliff
- Purdue University Center for Cancer Research, West Lafayette, IN.,Department of Comparative Pathobiology, Purdue University, West Lafayette, IN
| | - Deborah W Knapp
- Purdue University Center for Cancer Research, West Lafayette, IN.,Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN
| | - Ruben C Aguilar
- Purdue University Center for Cancer Research, West Lafayette, IN.,Department of Biological Sciences, Purdue University, West Lafayette, IN
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