Imaging brain tumours to develop image guided focused ultrasound delivery of anti-PDL1

Primary Supervisor: Maya Thanou, King’s College London

Secondary supervisor: Darren Hargrave, UCL

Tertiary supervisor: Elwira Szychot, Great Ormond Street Hospital for Children

Quaternary supervisor: Antonios Pouliopoulos, King’s College London

Project

There is currently no effective treatment for diffuse intrinsic pontine glioma (DIPG). Despite the development of novel pharmacological interventions, treatment outcomes remain poor and median survival after diagnosis is only 9 months. Large biomolecules do not cross the blood-tumour barrier (BTB) in sufficient concentrations. The consequence is that most clinical trials fail to significantly increase survival as immunotherapies do not safely cross biological barriers to stop or reverse tumour growth. Pembrolizumab is currently in clinical trials for DIPG however penetration to the tumour may be seriously limited.

A multitude of approaches has been tested in an effort to increase delivered doses into DIPG. Most notably, convection-enhanced chemotherapy has shown promise, by locally increasing the chemotherapeutic concentration and increasing the survival. However, most approaches are either invasive or non-targeted. The only method that allows both non-invasive and targeted drug delivery into the brain is the combined used of focused ultrasound (FUS) and microbubbles. Ultrasound forces the systemically administered microbubbles into oscillations, which mechanically disrupt the BTB and allow passage of large molecules.
In this project we aim to modulate the BTB and improve biological therapies? permeation in ?hard-to-treat? tumours such as DIPG. We will investigate if applied focused ultrasound microbubbles and/or novel phase change nanodroplets (PCND) are efficient tools to improve penetration across the BTB and within the brain tumour. Further, we will introduce biotherapeutics co-administered with the cavitation agents. Perfluorocarbon core lipidic droplets respond to ultrasound by gas evolution turning to bubbles but they are currently in development due to their biological stability advantages. When bubbles or PCND cavitate they affect the permeability of the BTB and allow the permeation of the biotherapeutics into the tumours. To monitor these phenomena, microbubbles, PCND and antibodies will be tagged, allowing their tracking to be followed by NIRF preclinical imaging. We will introduce anti-PD-1 on the PCND using chemical coupling. PCND (120nm) turn to microbubbles (1-2µm) that cavitate in a similar manner as the microbubbles. The PCND platform can accommodate a combination of biotherapeutics as part of the lipidic layer.

Key objectives are:

1. Formulate and characterise novel NIRF labelled microbubbles and PCND, for their imaging and ultrasound responsive properties. These will be labelled using previously developed XLA750-NIRF/Rhodamine lipid conjugates (Y1)
2. Label Anti-PD-1 (A-PD1) with near infra-red fluorescence (NIRF) for image tracking in vivo. C57BL/6 mice will be used to develop tumours in the brain (using a murine cell line model of proneural glioma). NIRF imaging will be used to monitor distribution of antibodies and the carrier of antibodies, in tumours (Y1-2).
3. Investigate the effect of focused ultrasound on A-PD-1-PCND bio-distribution in the murine model (in vivo) using imaging and tissue analysis. (Y2-3)
4. Combine derived data from modelling and in vivo bio-distribution data to design the focused ultrasound application protocol. Analyse the effects of the microbubble vs PCND mediated delivery across BTB (Y3).
5. Assess the ability of focused ultrasound, in combination with A-PD-1 PCND with and without panobinostat to stop tumour growth in the murine DIPG models (Y4).

Candidate background

The PhD candidate will need to have knowledge of chemistry to develop the biotherapeutics, and good understanding of physics of the ultrasound.

Potential Research Placements

• Antonios Pouliopoulos,  Department of Surgical & Interventional Engineering, King’s College London
• Laura Peralta, Biomedical Engineering and Imaging Sciences, King’s College London
• JP Martinez, Department of Developmental Biology and Cancer, UCL

References

1. Englander, Z.K., Wei, HJ., Pouliopoulos, A.N. et al. Focused ultrasound mediated blood?brain barrier opening is safe and feasible in a murine pontine glioma model. Sci Rep 11, 6521 (2021). doi.org/10.1038/s41598-021-85180-y
2. Cressey P, Amrahli M, So PW, Gedroyc W, Wright M, Thanou M. Image-guided thermosensitive liposomes for focused ultrasound enhanced co-delivery of carboplatin and SN-38 against triple negative breast cancer in mice. Biomaterials. 2021 Apr;271:120758. doi: 10.1016/j.biomaterials.2021.120758.
3. Hargrave D. Pediatric diffuse intrinsic pontine glioma: can optimism replace pessimism? CNS Oncol. 2012 Nov;1(2):137-48. doi: 10.2217/cns.12.15.
4. Szychot E, Walker D, Collins P, Hyare H, Shankar A, Bienemann A, Hollingworth M, Gill S. Clinical experience of convection-enhanced delivery (CED) of carboplatin and sodium valproate into the pons for the treatment of diffuse intrinsic pontine glioma (DIPG) in children and young adults after radiotherapy. Int J Clin Oncol. 2021 Apr;26(4):647-658. doi: 10.1007/s10147-020-01853-0.
5. Lieberman NAP, DeGolier K, Kovar HM, Davis A, Hoglund V, Stevens J, Winter C, Deutsch G, Furlan SN, Vitanza NA, Leary SES, Crane CA. Characterization of the immune microenvironment of diffuse intrinsic pontine glioma: implications for development of immunotherapy. Neuro Oncol. 2019 Jan 1;21(1):83-94. doi: 10.1093/neuonc/noy145.