PhD Scientific Days 2021

TT_I_P: Theoretical and Translational Medicine I. Posters

Modulated Electro-Hyperthermia Induces a Prominent Local Stress Response and Growth Inhibition in Triple Negative Mouse Breast Cancer

Text of the abstract

Introduction: Effective therapy of triple-negative breast cancer (TNBC) has not yet been achieved. Modulated electro-hyperthermia (mEHT) is a novel therapeutic option, based on the selective heating and energy transfer to the tumor tissue by an electromagnetic field.

Aims: Investigate the antitumoral effects of mEHT in TNBC mouse model and identify molecules that can serve as potential therapeutic targets.

Methods: Mouse TNBC 4T1 and 4T07 cells were inoculated orthotopically into female BALB/c mice. Tumor growth was measured by digital caliper and ultrasound (Phillips Sonos 5500). Animals were randomized into sham (n=9-10) and mEHT (n=8-11) treated groups and received treatment 3 or 5 times in every 48 hours with Labehy 200 (Oncotherm Ltd.). 24 hours after last treatment, tumors were dissected, weighed and processed. Slides were evaluated digitally (Caseviewer, 3DHistech Ltd.). Ratio of destructed vs whole tumor area (TDR%) was evaluated on H&E and cleaved caspase 3 stained slides. Heat-shock protein (HSP70) and Ki67 proliferation marker were evaluated (relative mask area %). Tumor samples were investigated with NGS and pathway analysis, and validated with Nanostring and mass spectrometry. Heat shock inhibition of KRIBB11 and effect on cell viability was studied in vitro.

Results: mEHT treatment reduced size growth (sham: 5.7x, mEHT: 2.4x relative to pre-treatment (day 6), p<0.0001) and weight (sham: 288.3±58.1 mg vs mEHT: 85.3±21.3 mg, p<0.05) in mEHT treated group, compared to sham group. HSP70 expression was 6.1x and cC3+ destructed tumor area was 6.3 x higher in treated group (p<0.05 and p<0.001) and the Ki67+ nucleus/mm2 count was significantly lower (sham: 2874 ± 193.6 pcs/mm2 vs mEHT: 1737 ± 315.3 pcs/mm2, p<0.05). NGS revealed that most upregulated genes are stress-related and fit into Response to Stimulus pathway (GO:0050896). KRIBB11 effectively decreases the expression of two identified molecules (HSP70, C4b) and tumor cell viability in vitro.

Conclusion: Repeated mEHT treatment can efficiently inhibit tumor growth and proliferation with the upregulation of several stress-related molecules. Inhibition of these molecules can potentiate mEHT’s effect and may improve the effectiveness of treatment.

Funding: NVKP_16-1-2016-0042; Dr. Korányi András az Egészségmegőrzés és Egészségkultúra Fejlesztéséért Alapítvány; EFOP-3.6.3-VEKOP-16-2017-00009

University and Doctoral School

Semmelweis University, Doctoral School of Theoretical and Translational Medicine