There are several examples of nanomaterials that are currently used in clinical oncology (Doxil, Genexol-PM and Abraxane to name few). All of these result in cancer therapy with a several fold decrease of the drug side-effects. Nanocarriers have a size bigger than the renal cutoff (c.a. 10nm) and smaller than 100nm, so they accumulate in the tumour by diffusing through the leaky tumour vasculature (enhanced permeability and retention-EPR). However, there are several tumours where access is not guaranteed via the vasculatures as well as cases (see peritoneal carcinomatosis) where the primary tumour metastasise into not vascularised nodules. Hence relying en rely on EPR is not enough to guarantee targeted therapy and this can be achieved by introducing more specific cellular recognition features, the ability to enter cancer cells and release their therapeutic cargo on site. In the last ten years, we have designed vesicles using synthetic polymers, a.k.a. polymersomes, that can encapsulate both hydrophobic and hydrophilic molecules. The polymersome macromolecular nature allows multivalency and enhances protein-fouling resistance. Most importantly, polymersomes can be made responsive to external stimuli and release their cargo on demand. We have designed polymersomes that consist of a combination of different blocks, each of which possess important proper es for use in biomedicine. This approach enables us to engineer carriers with a high degree of control over on their shape and topology. We have associated these physical features with biological activity and disclosed new ways to improve cellular specificity. We have developed a pH sensitive polymersomes that enter cells via endocytosis and escape from early endosomes (EE) to release their cargo within the cell cytosol. We achieve this using a polymersome that at EE pH=6.2 rapidly disassembles. inducing a temporary EE membrane destabilisation with concomitant cargo escape. As we demonstrated with doxorubicin to treat both melanoma cells (HBL) and drug resistant and highly metastatic melanoma cells (A-375-SM) [See figure], intracellular delivery augments the drug potency considerably. A single polymersome can encapsulate hundreds of drug molecules and hence it delivers considerable more drug within a single cell (See figure on the left -top graph). This, in turn, enhances drug potency and selectivity (See figure on the left bottom graph ) inducing faster therapeutic responses and limiting drug resistance. Polymersomes can also be loaded with several drugs to harness combination therapy. We have recently observed that poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) polymersomes target Scavenger receptor-B1 over-expressed in cancer. We have evaluated polymersomes delivery in vivo demonstrating that these target very quickly solid tumours and are retained for up to 24hr. This creates the ideal conditions to deliver drugs more effectively in vivo enabling a high concentration of drugs within the solid tumours. More recently, in collaboration with the Ruoslahti and Teesalu labs at the Sanford-Burnham Medical Research Institute in San Diego, we have demonstrated that pH sensitive polymersomes either as pristine or functionalised with iRGD tumour- penetrating peptide are very efficient in targeting and treating peritoneal carcinomatosis (PC) both generated by colorectal and gastric cancers. Polymersomes can target tumours very effectively and can penetrate their interior with minimal interaction with the local vasculature and hence maximum retention.
Alongside the drug delivery effort, we have been studying Ki-67, a nuclear protein that has been used in cancer diagnostic because of its specific cell-cycle dependent expression profile. After quantifying and characterising the expression level of Ki-67, as a function of the cell cycle, we found out that the two main splice variants of the protein (i.e. α and β) are differently regulated in non-cancerous and cancerous cells both at mRNA and protein level. We were able to correlate the presence of the α variant of the protein with the progression through the interphase of cell-cycle. We also observed that the different expression profiles correspond to different degradation pathways for non-cancerous and cancerous cells. Furthermore, Ki-67 is continuously regulated and degraded via proteasome system in both cell types, suggesting an active control of the protein. However, we also observed a putative extranuclear elimination pathway of Ki-67 where it is transported to the Golgi apparatus. Our evidence in the different expression of the splice variants may represent a milestone for the development of new targets for cancer diagnostic and prognostic. Additionally, the unexpected extranuclear elimination of Ki-67 strongly suggests that this protein must be looked at also outside of the “nuclear box”, as thought to date.
- X. Tian*, Y. Zhu, M. Zhang, L. Luo, J. Wu, H. zhou, L. Guan, G. Battaglia, and Y. Tian* Localization Matters: A Nuclear Targeting Two-Photon Absorption Iridium Complex Induced Intracellular Immigration and Dual- damage in Photon Dynamic Therapy Chem. Commun., 2017, just accepted DOI: 10.1039/C6CC09470H.
- L. Chierico, L.Rizzello*, L. Guan, A. Joseph, A. Lewis and G. Battaglia* The role of the two splice variants and extranuclear pathway on Ki-67 regulation in non-cancer and cancer cells PLoS One, 2017, 12(2): e0171815.
- L. Simón-Gracia, H. Hunt, P. Scodeller, J. Gaitzsch, V. R. Kotamraju, K. N. Sugahara, O. Tammik, E. Ruoslahti, G. Battaglia, and T. Teesalu "iRGD peptide conjugation potentiates intraperitoneal tumor delivery of paclitaxel with polymersomes" Biomaterials 2016, 104, 247–257
- L. Simón-Gracia, H. Hunt, P. Scodeller, J. Gaitzsch, G. B. Braun, A. A. Willmore, E. Ruoslahti, G. Battaglia, and T. Teesalu Paclitaxel-loaded Polymersomes for Enhanced Intraperitoneal Chemotherapy Mol. Cancer Ther. 2016, 15, 670-679
- M. G. Walker, P. J. Jarman, M. R. Gill, X. Tian, H. Ahmad, P. A. N. Reddy, L. McKenzie, J. A. Weinstein, A. J. H. M. Meijer, G. Battaglia, C. G. W. Smythe, and J. A. Thomas A Self-Assembled Metallomacrocycle Singlet Oxygen Sensitizer for Photodynamic Therapy Chem. Eur. J. 2016, 22, 5996–6000
- L. Guan, L. Rizzello, and G. Battaglia Polymersomes and their applications in cancer delivery and therapy Nanomedicine, 2015, 10, 2757-2780
- G. Fullstone, J. Wood, M. Holcombe and G. Battaglia Modelling the Transport of Nanoparticles under Blood Flow using an Agent-based Approach Sci. Rep. 2015, 5, 10649
- H. Colley, V. Hearnden, M. Avila-Olias, D. Cecchin, I. Canton, J. Madsen, N. Warren, S. Armes, S. MacNeil, Sheila, K. Hu, J. McKeating, C. Murdoch, M. Thornhill, and , G. Battaglia Polymersome-mediated delivery of combination anti-cancer therapy to head and neck cancer cells: 2D and 3D in vitro evaluation Mol. Pharmac. 2014, 11 (4), 1176–1188
- C. Pegoraro, D. Cecchin, L. Simon-Garcia, N. Warren, J. Madsen, S. P. Armes, A. Lewis, S. MacNeil, G. Battaglia* Enhanced drug delivery to melanoma cells using PMPC-PDPA polymersomes Cancer Lett. 2013, 334, 328-37
- M. Gill, G. Battaglia, C. Smythe and J. Thomas Dual function ruthenium(II) DNA light-switches: cellular imaging and cytotoxicity ChemBioChem 2011, 12 (6), 877-880
- C. Murdoch, K. J. Reeves, V. Hearnden, H. Colley, M. Massignani, I. Canton, J. Madsen, A. Blanazs, S. P. Armes, A. L. Lewis, S. MacNeil, N. J. Brown, M. H. Thornhill and G. Battaglia* Internalization and biodistribution of polymersomes into oral squamous cell carcinoma cells in vitro and in vivo Nanomedicine 2010, 5, 1025-1036.