Pint of Science, Newstead Brewing Co., Newstead, QLD – 20th of May, 2019.

Pint of Science is an international organization aimed at creating a comfortable and relaxed environment for scientists to discuss their work to the general public. The following is a brief excerpt from the 2019 program about my talk:

Join me to hear about the future of cancer treatment using personalised and smarter solutions called nanomedicines, and see how we are improving the outlook for patients with tumours, while also helping our canine friends.

37^th Australasian Polymer Symposium – Novotel Twin Waters, Twin Waters, QLD, Australia. 10^th – 13^th of November, 2019.

Chemotherapetics such as doxorubicin (DOX) are of interest to work as synergistic pairs with enzyme inhibitors (camptothecin, CPT) to increase the efficacy of treatment. We have prepared a hyperbranched polymer dual-theranostic system with site-specific synergistic delivery of two drugs on a single construct. The nanotheranostic also contained Cy5 as an imaging tracer and was targeted using a bisbepcific antibody with affinity for breast cancer.  The carrier exhibited release of both molecules in two-time scales by exploiting both redox and hydrolytic mechanisms for CPT and DOX, respectively. The release of the drug and cellular uptake were validated in vitro, and intracellular trafficking was also investigated with confocal microscopy. Both the targeting towards epidermal growth factor receptor (EGFR) and the synergistic release of drugs lead to an enhanced therapeutic response with no observable adverse effects on the mouse health.  The results show promising potential for this system as a synergistic treatment for breast cancer.

Centre of Excellence for Convergent Bio-Nano Science and Technology 5^th Annual Workshop, Healesville, VIC, Australia, 27^th – 29^th of November, 2019.

As postdoctoral leader on the signature project for the CBNS, I deliver the annual presentation of the project’s progress at the Annual Research Workshop.

10^th International Nanomedicine Conference – Sydney, New South Wales, Australia. 25^th of June, 2019.

Successful realisation of nanomedicines in clinical application is limited and can be considerably attributed to the biological heterogeneity between animals used in preclinical testing, and the patients assessed in clinical trials. In the modern era of a search for personalised treatment nanomedicines provide the perfect architecture to build an individualised treatment plan, but translation of these new constructs requires a robust and flexible treatment methodology that can be validated not only in mice but in animal models more similar to humans. Here we report on the first ever comparative oncology approach to the diagnosis and treatment of a canine patient with spontaneously occurring prostate cancer (Figure 1) with targeted nanomedicines. The canine patient was diagnosed with prostate cancer and the standard clinical tracer targeted towards prostate-specific membrane antigen (PSMA) 68Ga-PSMA was used to confirm this diagnosis using PET-CT. A nanomedicine prepared for the same target was also injected at a later time. Neither the 68Ga-PSMA or nanomedicine were able to positively identify the tumour, and after biopsy it was found that the tumour was in fact PSMA negative. The canine was treated with a nanomedicine loaded with a chemotherapeutic and after analysis of a biopsy of the tumour tissue taken prior to treatment, a more specific target (EGFR) was found to be overexpressed in the cancer. After imaging a second time with the nanomedicine targeted to this receptor, positive identification of the tumour was made. MRI also revealed a change in the composition of the tumour tissue, indicating a positive effect by the therapeutic nanomedicine and further validating the application of these constructs for use in future personalised medicine approaches to cancer treatment in humans.

ARC Joint Symposium – Advanced Bioengineered Systems, Brisbane, Australia, 20^th of November, 2018.

A discussion of the various animal models that are used for the investigation of nanomedicines and their relative strengths and weaknesses towards developing more robust therapeutic delivery systems was given.

Centre of Excellence for Convergent Bio-Nano Science and Technology 4^th Annual Workshop, Terrigal, NSW, Australia, 28^th – 30^th of November, 2018.

An overview of the challenges in developing personalised nanomedicines and was given at this year’s CBNS Annual Research Workshop. In particular the topic of choosing the best animal model for the research question as well as translating information from one model to another to progress work towards clinical application.

11^th Annual Scientific Meeting for Cooperative Trials Group for Neuro-Oncology (COGNO), Brisbane, Australia, 7^th-9^th of October, 2018.

As part of a clinically focussed conference, I gave a brief talk on the work towards the development of nanomedicines to treat glioblastoma.  This talk did not have an abstract, but the work is similar to another talk given previously. The abstract for this is copied below:

Nanomaterials come in a plethora of designs, shapes, chemical formulations, sizes, and ionic forms and can be readily tuned to surpass many of the biological barriers within the body, but have had limited success in surpassing the final frontier of barriers: the blood-brain barrier (BBB). While their size is a significant advantage of nanoparticles for their delivery to solid tumour masses, it is also their Achilles’ heel for crossing the BBB. A major area of interest for nanoparticle therapeutics is the delivery to glioblastoma (GBM), as it is the most aggressive form of brain cancer. Herein we report the use of simultaneous PET-MRI to develop a toolkit for monitoring tumour progression and its effect on BBB integrity of a spontaneous transgenic glioma model1,2, for the purpose of establishing when the BBB is compromised enough for nanoparticles to cross. A series of T1, T2, and dynamic contrast enhanced MRI images along with simultaneous PET of 18FDOPA were used to devise a set of in vivo imaging markers that could establish tumour volume and a measure of BBB integrity. PET was again used to analyse the ability of a 64Cu labelled bispecific antibody targeted hyperbranched polymer (HBP) 3 cross the BBB at different stages of GBM progression. As expected, larger tumour volumes and a higher degree of leaky vasculature correlate with increased BBB permeability by the HBP. This measure can be applied in the future to different sized nanoparticles and other materials to enable better development of BBB-penetrating nanocarriers.

Centre of Excellence for Convergent Bio-Nano Science and Technology 3^rd Annual Workshop, Twin Waters, QLD, Australia, 25^th – 27^th of October, 2017.

As postdoctoral leader on the signature project for the CBNS, I deliver the annual presentation of the project’s progress at the Annual Research Workshop.

The Centre for Advanced Imaging 4^th Annual Symposium, 29^th of September, 2017.

Nanomaterials come in a plethora of designs, shapes, chemical formulations, sizes, and ionic forms and can be readily tuned to surpass many of the biological barriers within the body, but have had limited success in surpassing the final frontier of barriers: the blood-brain barrier (BBB).  While their size is a significant advantage of nanoparticles for their delivery to solid tumour masses, it is also their Achilles’ heel for crossing the BBB.  A major area of interest for nanoparticle therapeutics is the delivery to glioblastoma (GBM), as it is the most aggressive form of brain cancer.  Herein we report the use of simultaneous PET-MRI to develop a toolkit for monitoring tumour progression and its effect on BBB integrity of a spontaneous transgenic glioma model^1,2, for the purpose of establishing when the BBB is compromised enough for nanoparticles to cross.  A series of T1, T2, and dynamic contrast enhanced MRI images along with simultaneous PET of ¹⁸FDOPA were used to devise a set of in vivo imaging markers that could establish tumour volume and a measure of BBB integrity.  PET was again used to analyse the ability of a ⁶⁴Cu labelled bispecific antibody targeted hyperbranched polymer (HBP) ³ cross the BBB at different stages of GBM progression.  As expected, larger tumour volumes and a higher degree of leaky vasculature correlate with increased BBB permeability by the HBP.  This measure can be applied in the future to different sized nanoparticles and other materials to enable better development of BBB-penetrating nanocarriers.

References
(1)        Stringer, B. W.; Bunt, J.; Day, B. W.; Barry, G.; Jamieson, P. R.; Ensbey, K. S.; Bruce, Z. C.; Goasdoué, K.; Vidal, H.; Charmsaz, S.; Smith, F. M.; Cooper, L. T.; Piper, M.; Boyd, A. W.; Richards, L. J. Oncotarget 2016, 7, 29306–20.

(2)        Chow, L.; Endersby, R.; Zhu, X.; Rankin, S.; Qu, C.; Zhang, J.; Broniscer, A.; Ellison, D.; Baker, S. Cancer Cell 2011, 19, 305–316.

(3)        Howard, C. B.; Fletcher, N.; Houston, Z. H.; Fuchs, A. V.; Boase, N. R.; Simpson, J. D.; Raftery, L. J.; Ruder, T.; Jones, M. L.; de Bakker, C. J.; Mahler, S. M.; Thurecht, K. J. Adv Healthc Mater 2016.

International Conference on BioNano Innovation, Brisbane, Australia, 27^th of September, 2017.

Nanomaterials come in a plethora of designs, shapes, chemical formulations, sizes, and ionic forms and can be readily tuned to surpass many of the biological barriers within the body, but have had limited success in surpassing the final frontier of barriers: the blood-brain barrier (BBB). Herein we report the use of simultaneous PET-MRI to develop a toolkit for monitoring tumour progression and its effect on BBB integrity of a spontaneous transgenic glioma model^1,2, for the purpose of establishing when the BBB is compromised enough for nanoparticles to cross.  A series of T1, T2, and dynamic contrast enhanced MRI images along with simultaneous PET of ¹⁸FDOPA were used to devise a set of in vivo imaging markers that could establish tumour volume and a measure of BBB integrity.  PET was again used to analyse the ability of a ⁶⁴Cu labelled bispecific antibody targeted hyperbranched polymer (HBP) ³ cross the BBB at different stages of GBM progression.  As expected, larger tumour volumes and a higher degree of leaky vasculature correlate with increased BBB permeability by the HBP.  This measure can be applied in the future to different sized nanoparticles and other materials to enable better development of BBB-penetrating nanocarriers.

References
(1)        Stringer, B. W.; Bunt, J.; Day, B. W.; Barry, G.; Jamieson, P. R.; Ensbey, K. S.; Bruce, Z. C.; Goasdoué, K.; Vidal, H.; Charmsaz, S.; Smith, F. M.; Cooper, L. T.; Piper, M.; Boyd, A. W.; Richards, L. J. Oncotarget 2016, 7, 29306–20.

(2)        Chow, L.; Endersby, R.; Zhu, X.; Rankin, S.; Qu, C.; Zhang, J.; Broniscer, A.; Ellison, D.; Baker, S. Cancer Cell 2011, 19, 305–316.

(3)        Howard, C. B.; Fletcher, N.; Houston, Z. H.; Fuchs, A. V.; Boase, N. R.; Simpson, J. D.; Raftery, L. J.; Ruder, T.; Jones, M. L.; de Bakker, C. J.; Mahler, S. M.; Thurecht, K. J. Adv Healthc Mater 2016.

International Nanomedicine Conference – Coogee, New South Wales, Australia.

Advances in materials synthesis have allowed for a multitude of well-defined biocompatible and stealthy nanoparticles of varying shape and size. For the treatment and diagnosis of cancer, these particles are often developed to exploit the enhanced permeability and retention (EPR) effect, but have limited in vivo efficacy due to their poor retention in tumour tissue. Addition of active targeting ligands with strong binding potentials to membrane receptors uniquely present on malignant cells have shown significant promise towards increasing the retention of nanoparticles in vivo. Many targeting vectors have been explored with some of the most promising types being antibodies; however, conjugation of these antibodies to the nanoparticles (NPs) using traditional chemistries is challenging and conditions can easily change per system. An ideal targeting system would be applicable to multiple types of NPs using a singular conjugation methodology. Recently, we have reported on the preparation of a bispecific antibody (BsAb) that has strong binding to VEGF receptors commonly overexpressed on cancer cells, and at its distal end an antibody specific towards methyl-terminated poly(ethyelene) glycol (PEG).¹ Herein we report the utility of this targeting method (Figure 1) toward the development of new diagnostic and therapeutic nanoparticles in murine models. Hyperbranched NPs constructed of methyl terminated PEG have been previously reported by us² and were used to test the in vivo stability and efficacy of the targeting system.  The prepared BsAbs were conjugated to the fluorescently labelled NPs via a short incubation procedure and subsequently injected intravenously into tumour bearing mice.  The accumulation of the particle was observed over several time points and ex vivo analysis was performed to validate the biodistribution observed in vivo.  The BsAb targeted NPs were found to show higher accumulation in the tumour compared to the off-target control (EphA2), and provide a promising and versatile targeting methodology for the investigation and treatment of tumours.

References

1. B. Howard, et al., Advanced Healthcare Materials, Accepted. (DOI: 10.1002/adhm.201600263R1)
2. V. Fuchs, et al., Biomacromolecules, 2015, 16(10), 3235-3247.

The Centre for Advanced Imaging 3^rd Annual Symposium, 19^th of October, 2016.

Advances in materials synthesis have allowed for a multitude of well-defined biocompatible and stealthy nanoparticles of varying shape and size. For the treatment and diagnosis of cancer, these particles are often developed to exploit the enhanced permeability and retention (EPR) effect, but have limited in vivo efficacy due to their poor retention in tumour tissue. Addition of active targeting ligands with strong binding potentials to membrane receptors uniquely present on malignant cells have shown significant promise towards increasing the retention of nanoparticles in vivo. Many targeting vectors have been explored with some of the most promising types being antibodies; however, conjugation of these antibodies to the nanoparticles (NPs) using traditional chemistries is challenging and conditions can easily change per system. An ideal targeting system would be applicable to multiple types of NPs using a singular conjugation methodology. Recently, we have reported on the preparation of a bispecific antibody (BsAb) that has strong binding to VEGF receptors commonly overexpressed on cancer cells, and at its distal end an antibody specific towards methyl-terminated poly(ethyelene) glycol (PEG).¹ Herein we report the utility of this targeting method (Figure 1) toward the development of new diagnostic and therapeutic nanoparticles in murine models. Hyperbranched NPs constructed of methyl terminated PEG have been previously reported by us² and were used in this study to test the in vivo stability and efficacy of the targeting system in multiple tumour models.  The prepared BsAbs were conjugated to the radiolabelled NPs via a short incubation procedure and subsequently injected intravenously in two sets of Balb/c nude mice bearing either subcutaneous or xenograft tumours.  The biodistribution and tumour accumulation of the NPs were observed over several time points in vivo and ex vivo.  The BsAb targeted NPs were found to show higher accumulation in the tumour compared to the off-target control, and provide a promising and versatile targeting methodology for the investigation and treatment of tumours.

References:

1. C.B. Howard, et al., Advanced Healthcare Materials, Accepted. (DOI: 10.1002/adhm.201600263R1)
2. A.V. Fuchs, et al., Biomacromolecules, 2015, 16(10), 3235-3247.

35^th Australasian Polymer Symposium, Gold Coast, Queensland, Australia.

Fluorine-19 has become a nuclei of interest for MRI due to a 100% natural abundance, zero background in vivo, and a high nuclear magnetic resonance sensitivity. Its poor sensitivity in vivo, however; is a main hurdle for its effective use in clinical systems requiring highly fluorinated species to obtain a signal. Hyperbranched polymers provide a biocompatible and customisable platform for selectively localising polyfluorinated ¹⁹F-MRI agents and have been shown to be successful in a myriad of applications, both by us1 and others². The use of gadolinium for contrast enhancement has also been shown to significantly shorten the T1 and T2 relaxation times of not only ¹H but ¹⁹F nuclei as well.^2–4 By combining these two techniques we report a gadolinium enhanced polyfluorinated stimuli responsive hyperbranched polymer capable of changing its ¹⁹F and ¹H contrast upon action by external stimuli. To test this method a disulphide bond was utilized as it is well known to cleave in the presence of glutathione, an antioxidant upregulated in tumour cells. Upon release of the DOTA-Gd complex the 19F-MR signal intensity increases, thus creating an on/off switch that is dependent upon successful tumour cell internalization.

References:
1 Thurecht, K. J.; Blakey, I.; Peng, H.; Squires, O.; Hsu, S.; Alexander, C.; Whittaker, A. K. J. Am. Chem. Soc. 2010, 132, 5336–5337.
2 Li, Y.; Laurent, S.; Esser, L.; Elst, L. Vander; Muller, R. N.; Lowe, A. B.; Boyer, C.; Davis, T. P. Polym. Chem. 2014, 5, 2592.
3 De Vries, A.; Moonen, R.; Yildirim, M.; Langereis, S.; Lamerichs, R.; Pikkemaat, J. a; Baroni, S.; Terreno, E.; Nicolay, K.; Strijkers, G. J.; Grüll, H. Contrast Media Mol. Imaging 2014, 9, 83–91.
4 Ratner, a V; Quay, S.; Muller, H. H.; Simpson, B. B.; Hurd, R.; Young, S. W. 19F relaxation rate enhancement and frequency shift with Gd-DTPA. Investigative radiology, 1989, 24, 224–227.

Convergent Bio-Nano Science and Technology Workshop, Lorne, Victoria, Australia.

An abstract was not submitted for this presentation, but was on the same research project as presented at another conference this same year. The text for this abstract is below:

¹⁹F-MRI offers a unique diagnostic platform with minimal endogenous background signal in vivo and increased sensitivity.  Consequently, a targeted polyfluorinated contrast enhancement agent would be of significant benefit to clinicians for the diagnosis of a variety of diseases.  This report describes the synthesis of a hyperbranched ¹⁹F-MRI contrast enhanced polymer that was targeted towards a variety of carcinomas, and is “switched on” in cancerous tissue via a stimuli-responsive linker. A Gd³⁺ bound DOTA chelator connected via a cleavable disulfide linker was incorporated into the polymer.  While bound, the T2 of ¹⁹F remained too short to detect; but when cleaved by glutathione the ¹⁹F signal was observed, as the Gd³⁺ was no longer in close enough proximity to elicit a relaxation effect.  The T1 and T2s of both ¹H and ¹⁹F were measured for the polymer in varying concentrations of glutathione to illustrate this concept, yielding promising results.

14^th Pacific Polymer Conference – Kauai, Hawaii, USA.

¹⁹F-MRI offers a unique diagnostic platform with minimal endogenous background signal in vivo and increased sensitivity.  Consequently, a targeted polyfluorinated contrast enhancement agent would be of significant benefit to clinicians for the diagnosis of a variety of diseases.  This report describes the synthesis of a hyperbranched ¹⁹F-MRI contrast enhanced polymer that was targeted towards a variety of carcinomas, and is “switched on” in cancerous tissue via a stimuli-responsive linker. A Gd³⁺ bound DOTA chelator connected via a cleavable disulfide linker was incorporated into the polymer.  While bound, the T2 of ¹⁹F remained too short to detect; but when cleaved by glutathione the ¹⁹F signal was observed, as the Gd³⁺ was no longer in close enough proximity to elicit a relaxation effect.  The T1 and T2s of both ¹H and ¹⁹F were measured for the polymer in varying concentrations of glutathione to illustrate this concept, yielding promising results.