Delivery of Cancer Chemotherapeutics by Genetically Engineered Nanoparticles

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1 Delivery of Cancer Chemotherapeutics by Genetically Engineered Nanoparticles Ashutosh Chilkoti Department of Biomedical Engineering Duke University, Durham, NC 27708, USA

2 Requirements for systemic drug delivery systems for cancer chemotherapeutics Small, hence rapidly cleared increase size stealth coating Many cancer drugs are hydrophobic Solubilize drug Sub-optimal distribution in vivo Size, shape, interfacial properties Targeting Biodegradable, biocompatible, nontoxic Easy to scale-up Blue: Cytotoxic cancer drugs Red: Pathway inhibitors Green: Miscellaneous

3 Challenge: Despite trillions invested in drug development, their delivery remains an unsolved challenge Small molecules Peptides and proteins Nucleic acids

4 Elastin-like polypeptides n ELPs are peptide polymers Repeat unit is VPGXG Hydrophobicity of X influences thermal behavior Typical design parameters are chain length and identity of X

5 Elastin-like polypeptides n ELPs exhibit a lower critical solution temperature LCST phase transition

6 ELPs are made by genetic engineering 2. Fermentation 1. Assemble gene Introduce into E. coli 3. Lyse cells purify

7 So why ELPs for drug delivery? ELPs are smart polymers that can be completely and precisely engineered at the molecular level Genetically encoded Precise control of MW Monodisperse Main chain degradable non-toxic AA break down products High yields: ~ mg/l in E. coli shaker flask culture Drug-polymer architecture can be precisely controlled LCST trigger Phase transition LCST behavior allows fast, cheap and easy purification LCST transition can be triggered by ph, metal ions, light to create delivery systems that respond to multiple, orthogonal triggers Mers: MW (kda):

8 ELP are enormously flexible: many strategies possible Passive: T t >> body temperature enhanced permeability and retention (EPR) leaky vasculature + poor drainage enhanced tumor accumulation Active: mild hyperthermia (T t < 42ºC) Thermal targeting of tumors Duncan R. Nat. Rev Drug Dis (2003) Local T t < body T: In situ depot formation for sustained release Brachytherapy with ELP-radionuclide conjugate Delivery of biologics from an s.c..injectable depot: GLP-1

9 Chimeric polypeptide (CP) for passive targeting ELP Attachment segment Water soluble T t >> 37 C Charge neutral guest residues: Val : Ala : Gly [1: 8 : 7 Avoid renal filtration cutoff 62 kd Attachment points for high drug loading 8 Cys clustered at C-terminus of ELP as (GGC) 8 segment

10 Chimeric polypeptide (CP) for passive targeting ELP Attachment segment [VPGX V:A:G[1:8:7 G 160 [WPC(GGC) 7

11 ph-triggered release of Dox from ELP Doxorubicin H H N H BDX H NH 2 H H NH N H N BMPH H N NH 3 + H H 200 nm NH 2 H JA MacKay, M Chen, W Liu, J McDaniel, and A Chilkoti, Nature Materials, 8: (2009)

12 Attachment of hydrophobic cancer drugs drives self-assembly into nanoparticles Doxorubicin nanoparticles Paclitaxel nanoparticles 200 nm JA MacKay, M Chen, W Liu, J McDaniel, and A Chilkoti, Nature Materials, 8: (2009)

13 ph triggered drug release from ELP-Dox nanoparticles Drug Release (% of initial) ph5 ph Time (hrs) Cell Viability (%) CP-Dox Dox Doxorubicin Concentration (µm)

14 CP-Dox nanoparticles have favorable biodistribution Tumor Doxorubicin (% ID/g) Dox Time (hrs) 24 2 * CP-Dox Heart Doxorubicin (% ID/g) Dox * Time (hrs) 24 2 CP-Dox

15 A single dose of ELP-Dox nanoparticles abolish tumors and cure mice of tumors Tumor Volume (mm 3 ) CP-Dox, 20 mg/kg Dox, 5 mg/kg PBS Dosing Time Post-implantation (days) Cumulative Survival Median=66 Dox CP-Dox Dox PBS CP-Dox Median=27 Day 0 Median= Time Post-implantation (days) Mackay et al., Nature Materials 2009

16 Similar effects seen in even more challenging models with Doxorubicin and Paclitaxel nanoparticles

17 ELP-Paclitaxel nanoparticles outperform Abraxane rthotopic MDA MB-231 breast cancer Subcutaneous PC-3 prostate cancer Nature Communications, 2016

18 Summary and Future Plans ELPs self-assemble upon attachment of hydrophobic drugs ELP-Dox nanoparticles are effective in multiple mouse models of cancer New ELP-paclitaxel nanoparticles show promise Future Plans under DCI/NCSU funding Phase I clinical trial of CP-DX in dogs SA1. Develop an optimized standard protocol for the formulation of CP-DX in large enough quantities to be used a large animal (canine) model (Chilkoti laboratory: Duke): NGING SA2. Undertake a small Phase I study to evaluate the safety of CP-DX in normal dogs and determine an appropriate dosage range using standard PK/PD analyses (Suter labratory NCSU): PLANNED FR MARCH 2017

19 Acknowledgements People Dr. Darin Furgeson, Dr. Andrew MacKay, Dr. Mingnan Chen: ELP-Dox nanoparticles Dr. Jayanta Bhattacharya: ELP-paclitaxel nanoparticles Jonathan Mac Daniel: Attachment triggered self-assembly and thermally triggered nanoparticles Miriam Amiram and Kelli Luginbuhl: PDs Felipe Garcia Quiroz: ERCA and Syntactomers Funding NIH R01-EB Collaborators Kevin Vargo and Prof. Dan Hammer (UPenn): Cryo-TEM NIH R01-EB00188 NIH R01-GM61232 NIH R01-DK NIH R01-DK NIH R21-EB009904