Amin Mehra - Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
Reza Mehrkar - Department of Medical Laboratory Sciences, Faculty of Paramedicine, Tabriz University of Medical Sciences, Tabriz, Iran
Amir Fakhri - Department of Biology, Urmia Branch, Islamic Azad University, Urmia, Iran
Pedram Jabbari Fard - Department of Microbiology, Faculty of Basic Science, Science and Research Branch, Islamic Azad University, Tehran, Iran
Mohammad Reza Asgharzadeh - Department of Biology, Urmia Branch, Islamic Azad University, Urmia, Iran
Mohammad Hossein Ghaffari Agdam - Department of Microbiology, Faculty of Basic Science, Science and Research Branch, Islamic Azad University, Tehran, Iran
Rasoul Sharifi - Department of Biology, Ahar Branch, Islamic Azad University, Ahar, Iran

Background: This study investigates the relative expression of the Na+, HCO۳- cotransport gene NBCn۱, and caspase-۳ within the tumor microenvironment of human breast cancer, considering the in vivo microenvironment. Method: In this experimental study, breast cancer MDA-MB-۲۳۱ cells were cultured under normoxia/hypoxia conditions for ۲۴, ۴۸, and ۷۲ hours with varying glucose concentrations (۵.۵, ۱۱, and ۲۵ mM). The mRNA expression of NBCn۱ and caspase-۳ was evaluated using real-time polymerase chain reaction. The stability and binding pocket of NBCn۱ were assessed using DispHred and the Computed Atlas of Surface Topography of proteins (CASTp) servers, respectively. The location prediction of the protein was determined using the Transmembrane Helices; Hidden Markov Model (TMHMM) server. Results: Normoxia led to an increase in NBCn۱ expression during all three time periods, displaying heterogeneity. The expression was particularly elevated at glucose concentrations of ۲۵ and ۵.۵ mM. In hypoxic conditions, gene expression was reduced; however, an increase in glucose concentration enhanced SLC۴A۷ expression. Specifically, a glucose concentration of ۲۵ mM led to decreased caspase-۳ expression under hypoxic conditions. In silico studies revealed that SLC۴A۷ becomes disordered when the pH falls below ۷, with most amino acids in the binding pocket being nonpolar. Conclusion: The heightened risk of breast cancer metastasis may be linked to the upregulation of SLC۴A۷ and downregulation of caspase-۳ expression, underscoring their fundamental roles in cancer treatment and prevention. SLC۴A۷ is a transmembrane protein, and its folding is pH-dependent.

Tumor Microenvironment, SLC۴A۷, Caspase-۳, Breast neoplasms, In silico