EventsThe 5th International Electronic Conference on Cancers
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Published
This submission belongs to the session S3. Drug Resistance and Anti-cancer Drug Development and Screening of the event The 5th International Electronic Conference on Cancers
Published date
05 Jun, 2026
Academic Editor
author-avatarFarrukh Aqil
Citation
Ana Catarina Matos, Sara Reis Moura, Rúben Moreira, Alessandra Ciucci, Sara Ricardo, Maria Inês Almeida, Silva Mulhovo, Camilla Nero, Sonia Minuzzo, Marco Alves, Claudio Sette, Stefano Indraccolo, Maria José Ferreira, Lucília Saraiva, Restoring therapeutic vulnerability in Multidrug-Resistant Ovarian Cancer with a first-in-class disruptor of the BRCA1–BARD1 interaction, in Proceedings of The 5th International Electronic Conference on Cancers, 10 June–12 June 2026, MDPI: Basel, Switzerland
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Restoring therapeutic vulnerability in Multidrug-Resistant Ovarian Cancer with a first-in-class disruptor of the BRCA1–BARD1 interaction

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Ana Catarina Matos 1
Sara Reis Moura 2,3
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Rúben Moreira 4
Alessandra Ciucci 5,6
Sara Ricardo 7,8
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Maria Inês Almeida 2,3
Silva Mulhovo 9
Camilla Nero 10
Sonia Minuzzo 11
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Marco Alves 4
Claudio Sette 5,6
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Stefano Indraccolo 11,12
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Maria José Ferreira 13
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Lucília Saraiva 1
1. LAQV/REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal, Portugal
2. Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal, Portugal
3. Institute for Research and Innovation in Health (i3S), Universidade do Porto, Rua Alfredo Allen, 4200-15 135, Porto, Portugal
4. Department of Medical Sciences, Institute of Biomedicine (iBiMED), University of Aveiro, 3810-193 Aveiro, Portugal, Portugal
5. GSTeP Organoids Research Core Facility, IRCCS Fondazione Policlinico A. Gemelli, Rome, Italy, Italy
6. Department of Woman and Child Health and Public Health, Catholic University of the Sacred Heart, Rome, Italy
7. Associate Laboratory i4HB - Institute for Health and Bioeconomy, University Institute of Health Sciences (1H-TOXRUN, IUCS-CESPU), Gandra 4585-116, Portugal, Portugal
8. UCIBIO - Applied Molecular Biosciences Unit, Toxicologic Pathology Research Laboratory, University Institute of Health Sciences (1H-TOXRUN, IUCS-CESPU), Gandra 4585-116, Portugal
9. Centro de Estudos Moçambicanos e de Etnociências (CEMEC), Faculty of Natural Sciences and Mathematics, Pedagogical University, 21402161, Maputo, Mozambique, Mozambique
10. Department of Woman and Child Health and Public Health, Catholic University of the Sacred Heart, Rome, Italy, Italy
11. Department of Surgery, Oncology and Gastroenterology, University of Padova, Padova, Italy, Italy
12. Basic and Translational Oncology Unit, Veneto Institute of Oncology IOV - IRCCS, Padova, Italy
13. Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal, Portugal
Abstract

Ovarian cancer (OC) remains largely incurable due to the emergence of multidrug resistance (MDR) following platinum–taxane therapy through rewiring of DNA repair, metabolism, and drug efflux pathways. Strategies capable of collapsing this stress-adaptation network remain limited [1]. We developed BBIT20, a first-in-class small-molecule disruptor of the BRCA1–BARD1 interaction, essential to homologous recombination (HR) repair and genome stability.

BBIT20 was evaluated in BRCA-proficient and -mutated OC cell lines, MDR cells, patient-derived organoids (PDOs), and xenograft and patient-derived xenograft (PDX) mouse models. Activity was assessed alone and in combination with paclitaxel, carboplatin, and PARPi. Mechanistic studies included DNA repair profiling, apoptosis, and immune-evasion markers.

BBIT20 displayed BRCA status-independent cytotoxicity (IC50 4–6 µM), favorable selectivity over non-tumoral cells, and retained activity in MDR models without cross-resistance. In wtBRCA1 PDOs, BBIT20 reduced BRCA1 and RAD51 levels, inducing DNA damage and apoptosis consistent with HR collapse. BBIT20 also modulated the E2F1-c-MYC-HDAC3 axis, triggered mitochondrial stress, and reduced ABCB1 drug-efflux expression.

Combination therapy showed strong synergy with paclitaxel, carboplatin, and PARPi (CI 0.08–<1), reducing effective doses by up to 20-fold in both sensitive and resistant OC models. In vivo, BBIT20 (2 mg/kg) reduced ascites formation and tumor burden in PDX models and achieved greater tumor growth inhibition than olaparib in xenografts. Combination therapy further supressed proliferation, HR and NHEJ repair, EMT, and angiogenesis markers while remaining well tolerated.

BBIT20 induces DNA repair–metabolic stress collapse and resensitizes MDR tumors to platinum, taxanes, and PARP inhibitors, supporting its development for refractory OC.

[1] Uboveja A et al. (2024)

Acknowledgments: This work was supported by FCT/MCTES through Project 2024.13556.PEX (https://doi.org/10.54499/2024.13556.PEX). A.C. Matos is supported by fellowship UI/BD/154513/2023. An international patent covering BBIT20 has been filed by S. Mulhovo, M.J. Ferreira, and L. Saraiva. L. Saraiva and M.J. Ferreira are co-founders of BBIT-Therapeutics, Lda.

Keywords
Ovarian Cancer
BBIT20
BRCA1-BARD1 interaction
Drug resistance
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