DETECTION OF CELLULAR BORON IN HUMAN

GLIOBLASTOMA BIOPSIES AFTER INFUSION OF BPA

A Detta, NP Lockyer, S Green, G Cruickshank

Dept Neurosurgery, QEHB & School of Cancer Sciences, University of Birmingham

Dept Medical Physics, QEHB & Dept Physics, University of Birmingham

Surface Analysis Research Centre, University of Manchester

Why GBM?

Most aggressive tumour known Incurable Causes greatest life-years-lost of any

oncological disease Causes costly morbidity

Why measure cellular boron?

Identify engagement of boronated drug with target tissue

Microscopic locus of boron dictates site of damage

Need 10-fold LESS boron intracellularly than extracellularly to cause cell death

Quantify microdosimetry

Why use SIMS

Best technique available for visualising cellular/subcellular boron

Generates visual images of isotopic composition and distribution

SIMS

High vacuum imaging technique Requires fastidious cryogenic procedures

to preserve chemical and structural integrity of tissue

Cryogenic procedure must obviate processing steps that would cause disturbance of native compartmentalisation of diffusible ions

However, detection limit is ~10ppm

Patient cohorts

1) Intravenous BPA x3 2) Intravenous BPA + BBB-D with

mannitol x3 3) Intracarotid BPA x3 4) Intracarotid + BBB-D with mannitol x1

Needle biopsy taken at 1-2h post BPA of Tumour & BAT

Not readily cryosectionableImprint tissue on Si or glass substrate

Liquid propane: unacceptable riskCryopreserve in isopentane-LN2

SIMS: frozen or freeze-dried

Histology

Bulk 10B quantification:ICP-MS

Store -80 oC

<30s

Pt 1 (IV BPA)Boron Na K

1h BAT 1h Tumour

Pt 1 (IV BPA)

2h BAT 2h Tumour

Pt 2 (IV BPA)

2h BAT 2h Tumour

Pt 3 (IV BPA)

2h Tumour

Pt 4 (IV BPA + BBB-D)

2h BAT 2h Tumour

Pt 5 (IV BPA + BBB-D)

2h BAT 2h Tumour

Pt 6 (IV BPA + BBB-D)

2h BAT 2h Tumour

Pt 7 (IA BPA)

2h BAT 2h Tumour

Pt 8 (IA BPA)

2h BAT 2h Tumour

Pt 9 (IA BPA)

2h BAT 2h Tumour

Pt 10 (IA BPA + BBB-D)

Analysis pending

Patients/Groups

Pt No. Age/gender

Diagnosis BPA infusion module

1 73/M OAII? IV

2 54/F GBM IV

3 55/M GBM IV

4 66/F GBM IV+BBBD

5 70/M GBM IV+BBBD

6 51/M GBM IV+BBBD

7 57/M GBM IA

8 72/M GBM IA

9 57/M GBM IA

10 71/M GBM IA+BBBD

Preliminary ResultsBPA infusion module

SIMS B:C ratio ICP-MS (ppm)

T BAT T BAT

1. IV 0.04 (1)

0.03 (1)

6.6 5.2

2. IV 0.08 (3)

0.08 (3)

47 18

3. IV 0.04 (2)

NA 8.6 9.4

4. IV+BBBD 0.03 (2)

0.02 (2)

23.2 14.4

5. IV+BBBD 0.04 (1)

0.01 (1)

22.2 9.9

6. IV+BBBD 0.04 (1)

0.02 (1)

18.4 16.9

7. IA 0.08 (2)

0.10 (2)

32.2 13.7

8. IA 0.05 (2)

0.02 (2)

22.1 13.9

9. IA 0.04 (3)

0.03 (3)

17.8* 10.4

Results summary 1BPA

infusion

module

SIMS B/C ratio

T B

ICP-MS (ppm)

T B

IV 0.05+ 0.02

0.06+ 0.035

20.7+ 22.8

10.9+ 6.5

IV+BBBD

0.05+ 0.026

0.02+ 0.006

21.3+ 2.5

13.7+ 3.5

IA0.06+ 0.02

0.05+ 0.04

24.0+ 7.4

12.7+ 2.0

Results summary 2BPA infusion

moduleT:B SIMS boron

T:B ICP-MS boron

IV 0.8 1.9

IV+BBBD 2.5 1.6

IA 1.2 1.9

Conclusions

Cell-level boron can be measured in human GBM biopsies with SIMS

IA route possibly route of choice for optimal target engagement at tissue and cell-level dimensions

Tumour : BAT boron levels independent of route of infusion

SIMS suggests tumour boron levels a little higher than BAT whereas ICP-MS shows ~2-fold difference