Buenos Aires
Breast Cancer
Symposium

BA-BCS 2024

September 3 – 6, 2024

IFIBYNE Auditorium, FCEN-UBA

Poster No. 30

In vitro and in vivo effect of the combination of 2’-nitroflavone and safingol in breast cancer

Juan M. Anselmi Relats1, Leonor P. Roguin1, Nora M. Marder1, Magalí C. Cercato1, Julieta Marino1, Viviana C. Blank1

1.Instituto de Química y Fisicoquímica Biológicas .

Presenting Autor:
Anselmi Relats, Juan Manuel

Instituto de Química y Fisicoquímica Biológicas

Sphingosine kinase-1 (SPHK1), the enzyme that catalyzes the synthesis of the pro-oncogenic molecule sphingosine-1-phosphate, is commonly upregulated in breast cancer cells and has been linked with poorer prognosis. Therefore, SPHK1 targeting drugs have been proposed for breast cancer treatment, with better antitumor results when they are combined with chemotherapy. Previously, we demonstrated that the synthetic flavonoid 2’-nitroflavone (2´NF) exerted a potent and selective antiproliferative effect in murine HER2-positive LM3 mammary tumor cells. As we found that these cells overexpress SPHK1, we explored the antitumor action of the combination of the SPHK inhibitor safingol with 2´NF. In order to quantitatively characterize the interaction between 2´NF and safingol, dose-effect curves were analyzed by Compusyn software. Results showed combination indexes indicative of synergism in cells incubated with 5 μM of 2´NF and 0.6 μM of safingol (0.72±0.06, 48h and 0.71±0.01, 72h). Similar results were obtained when human HER2-positive MDA-MB-453 breast cancer cells were treated with 2´NF and safingol (0,65 ± 0,08, 48 h and 0,73 ± 0,06, 72 h). To explore the in vivo effect of the combination, we employed a syngeneic LM3 breast cancer murine model. Mice were treated with either vehicle, 2’NF (0.7 mg/kg), safingol (0.5 mg/kg) or the combination of both drugs. 2’NF treatment reduced tumor volume by 38 % (p<0.05) and safingol had no significant effect compared to vehicle-treated mice. However, when both drugs were administered together, tumor volume was reduced by ~85% (p<0.0001). Moreover, western blot analysis of tumor lysates revealed that combined treatment increased PARP cleavage and Bax protein levels and decreased anti-apoptotic Bcl-xL and Bcl-2 protein levels (p<0.05). In summary, the therapeutic efficacy of the combined treatment, which employs low doses of each drug, makes this formulation an attractive potential treatment for HER2-positive breast cancer.