In vitro and in vivo BNCT investigations using a carborane containing sulfonamide targeting CAIX epitopes on malignant pleural mesothelioma and breast cancer cells

Diego Alberti,Nicoletta Protti,Saverio Altieri,Alessia Michelotti,Annamaria Deagostino,Simonetta Geninatti Crich,Alberto Lanfranco

doi:10.1038/s41598-020-76370-1

Diego Alberti, Nicoletta Protti + Show 5 more

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https://doi.org/10.1038/s41598-020-76370-1

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Abstract

This study aims at merging the therapeutic effects associated to the inhibition of Carbonic Anhydrase IX (CAIX), an essential enzyme overexpressed by cancer cells including mesothelioma and breast cancer, with those ones brought by the application of Boron Neutron Capture Therapy (BNCT). This task was pursued by designing a sulfonamido-functionalised-carborane (CA-SF) that acts simultaneously as CAIX inhibitor and boron delivery agent. The CAIX expression, measured by Western blot analysis, resulted high in both mesothelioma and breast tumours. This finding was exploited for the delivery of a therapeutic dose of boron (> 20 μg/g) to the cancer cells. The synergic cytotoxic effects operated by the enzymatic inhibition and neutron irradiation was evaluated in vitro on ZL34, AB22 and MCF7 cancer cells. Next, an in vivo model was prepared by subcutaneous injection of AB22 cells in Balb/c mice and CA-SF was administered as inclusion complex with a β-cyclodextrin oligomer. After irradiation with thermal neutrons tumour growth was evaluated for 25 days by MRI. The obtained results appear very promising as the tumour growth was definitively markedly lower in comparison to controls and the CAIX inhibitor alone. This approach appears promising and it call consideration for the design of new therapeutic routes to cure patients affected by this disease.

Highlights

carborane functionalised sulfonamide (CA-SF) to the generation of an increasingly acidic extracellular space that facilitates tumour cell invasiveness[11,12]
The synthesis of the carborane functionalised sulfonamide (CA-SF) has been carried out following the procedure reported in detail in Material and Methods according to the synthetic procedure reported by Brinda et al.[14,16]
The experimental design to test the proposed methodology consisted of different steps, namely (i) assessment of Carbonic Anhydrase IX (CAIX) expression in the considered tumour cell lines; (ii) in vitro assessment of breast and mesothelioma tumour cell vitality and of the cellular uptake in the presence of increasing amounts of CA-SF; (iii) Boron Neutron Capture Therapy (BNCT) experiments on tumour cells that have been loaded with CA-SF and (iv) BNCT on a mesothelioma murine model upon the i.v. administration of CA-SF

Summary

Introduction

CA-SF to the generation of an increasingly acidic extracellular space that facilitates tumour cell invasiveness[11,12]. BNCT is a non-invasive therapeutic modality for treating locally invasive malignant tumours, successfully applied to primary brain tumours and recurrent head and neck cancer[27] This therapy combines low energy neutron irradiation with the presence of boron-containing compounds at the target cells. Neutrons are captured by nonradioactive 10B yielding 11B that disintegrates into alpha particles and lithium nuclei causing non reparable damage to the cell where they were generated, sparing the surrounding healthy ones This fact makes BNCT a powerful option for the treatment of disseminated metastasis and infiltrating tumours as mesothelioma and invasive breast ductal carcinoma, whose cure cannot be tackled by methods, such as surgery or conventional radiotherapy, because of a non-sufficiently accurate localization of the tumour lesion. The conventional radiotherapy cannot do such selective treatment because unavoidably significant masses of healthy tissue are exposed to high doses of radiation

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