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Cocktail & Poster Display session

26P - 3MST: A potential workhorse in H2S signaling trimmed by microRNA-548 in breast cancer


06 Mar 2023


Cocktail & Poster Display session


Alyaa Dawoud


Annals of Oncology (2023) 8 (1suppl_2): 100902-100902. 10.1016/esmoop/esmoop100902


A. Dawoud1, R.A. Youness2, H. Nafea1, T. Manie3, R.M. Abdel-Kader4, M. Gad1

Author affiliations

  • 1 Biochemistry, GUC - German University in Cairo, 11835 - New Cairo/EG
  • 2 Biology And Biochemistry, University of Hertfordshire Hosted by Global Academic Foundation, 11835 - Cairo/EG
  • 3 Breast Surgery Department, National Cancer Institute - Cairo University, 11796 - Cairo/EG
  • 4 Pharmacology & Toxicology Dept., GUC - German University in Cairo, 11835 - New Cairo/EG


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Abstract 26P


Gasotransmitters have been established as key players in cancer pathophysiology including breast cancer (BC). Hydrogen sulfide (H2S), being the newest member of gasotransmitters family, was found to be highly elevated in BC tissues. Cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3MST) are the endogenous producers of H2S in viable cells. High expression of CBS and CSE in BC tissues was noticed. However, 3MST received less attention. Thus, the aim of this work is to unravel the expression pattern and regulation of 3MST in BC patients and cell lines.


BC female patients (n=20) were recruited. Patients’ clinical features showed that 65% of patients had lymph node metastasis, 15% were in stage 3-4 of BC, 25% had tumor size ≥5 cm, and 45% were in premenopausal status. Total RNA was extracted using Biazol, reverse transcribed and quantified using qRT-PCR. Western blot analysis was used to quantify the protein. In-silico analysis was used to identify microRNAs (miRNAs) targeting 3MST. MDA-MB-231 cells were cultured and transfected using oligonucleotides. H2S levels were measured by fluorescence probe (AzMc). Functional analysis experiments such as trans-well migration, MTT and colony forming assays were performed in MDA-MB-231 cells following ectopic miR-548 expression.


3MST was found to be significantly up-regulated in BC tissues compared to the non-cancerous tissues. Significant high expression for 3MST was correlated to tumor size ≥5 cm, albeit not to lymph node metastasis nor to menopause. MiR-548 was listed among the top potential regulators of 3MST using 6 different bioinformatics softwares. Ectopic expression of miR-548 in MDA-MB-231 cells resulted in a marked repression of 3MST on both mRNA and protein levels. H2S levels were significantly repressed by 3MST siRNAs and miR-548 mimics. On the functional level, miR-548 markedly reduced cellular viability, migration and colony forming ability of MDA-MB-231 cells.


This study sheds light onto the significant involvement of 3MST in H2S signaling and its positive correlation with BC aggressiveness. Moreover, it highlights its potential target-ability using miR-548 as a novel tumor suppressor therapeutic approach in BC.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.


Swiss National Science Foundation (SNSF), grant SNF IZSTZ0_198887.


All authors have declared no conflicts of interest.

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