VALIDATION OF A NOVEL IN VITRO BREAST CANCER CHEMORESISTANCE PLATFORM IN NEOADJUVANT SETTING

Authors

  • Martina Lichtenfels Ziel Biosciences – Porto Alegre (RS), Brazil.
  • Camila Alves da Silva Ziel Biosciences – Porto Alegre (RS), Brazil.
  • Alessandra Borba Anton de Souza Pontíficia Universidade Católica do Rio Grande do Sul, Centro de Mama – Porto Alegre (RS), Brazil.
  • Heloisa Rezende Hospital Hinja – Volta Redonda (RJ), Brazil.
  • Luiza Kobe Pontíficia Universidade Católica do Rio Grande do Sul, Centro de Mama – Porto Alegre (RS), Brazil.
  • Isabela Miranda Pontíficia Universidade Católica do Rio Grande do Sul, Centro de Mama – Porto Alegre (RS), Brazil.
  • Antônio Luiz Frasson Pontíficia Universidade Católica do Rio Grande do Sul, Centro de Mama – Porto Alegre (RS), Brazil. Hospital Israelita Albert Einstein – São Paulo (SP), Brazil.
  • Caroline Brunetto de Farias Ziel Biosciences – Porto Alegre (RS), Brazil.

DOI:

https://doi.org/10.29289/259453942022V32S2013

Keywords:

Breast neoplasms, Neoadjuvant therapy, Neoplasm drug resistance

Abstract

Objective: The aim of this study was to validate a novel in vitro chemoresistance platform for two drugs commonly used
in the neoadjuvant setting for breast cancer (BC). Methods: Three BC cell lines (MCF-7 (luminal); SKBR3 (HER2+); and
MDA-MB-231 (triple-negative) were used to confirm the efficacy of the platform. Patients with invasive BC and partial
response to neoadjuvant chemotherapy were included in this initial report. Fresh tumor samples were collected during
surgery and dissociated to obtain the tumor cells. The tumor cells were cultured in the chemoresistance platform with
doxorubicin and paclitaxel and after 72-h cell viability was evaluated. The test result is defined based on cell viability as
low (<40%), medium (40–60%), and high (>60%) resistance. Results: The three BC cell lines presented low resistance to
doxorubicin, MCF-7 and SKBR3 cells also presented low resistance to paclitaxel, whereas MDA-MB-231 has intermediate
resistance. Samples from 10 BC patients with partial response to neoadjuvant chemotherapy were tested in the novel chemoresistance platform. All the patients received doxorubicin and paclitaxel as part of the treatment. The overall rate of
assay success was 100%. Regarding molecular subtypes, 40% were Luminal, 20% Luminal HER2, 10% HER2, and 30% triple-negative. The 10 samples presented 100% high resistance to paclitaxel. High resistance to doxorubicin was observed in
70% of the samples, intermediate in 10%, and low in 20%. The chemoresistance platform demonstrated that samples already treated with paclitaxel and doxorubicin in a neoadjuvant setting presented more high resistance to the drugs compared to the BC cell lines. Conclusion: This preliminary result demonstrated more high resistance in tumors previously
treated with doxorubicin and paclitaxel compared to BC cell lines without previous treatment and highlighted the success of the in vitro chemoresistance platform to test tumor samples after neoadjuvant treatment.

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Published

2026-04-01

How to Cite

Lichtenfels, M., Silva, C. A. da, Souza, A. B. A. de, Rezende, H., Kobe, L., Miranda, I., … Farias, C. B. de. (2026). VALIDATION OF A NOVEL IN VITRO BREAST CANCER CHEMORESISTANCE PLATFORM IN NEOADJUVANT SETTING. Mastology, 32(suppl.2). https://doi.org/10.29289/259453942022V32S2013

Issue

Vol. 32 No. suppl.2 (2022)

Section

Oral Presentation

License

Copyright (c) 2026 Martina Lichtenfels, Camila Alves da Silva, Alessandra Borba Anton de Souza, Heloisa Rezende, Luiza Kobe, Isabela Miranda, Antônio Luiz Frasson, Caroline Brunetto de Farias

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.