Context: Through the expression of different immunomodulatory molecules, mesenchymal stem cells (MSCs) play a significant role in the regulation of immune responses against tumor cells. Herein, the expression of major histocompatibility complex class I polypeptide-related sequence B (MIC B) as an immunomodulatory molecule was investigated on adipose-derived stem cells (ASCs) isolated from breast cancer patients (Stage II and III) and healthy individuals.
Materials and methods: ASCs were isolated enzymatically, and the expression of MIC B was measured using quantitative real-time polymerase chain reaction method before and after treatment with interferon γ (IFN-γ). The concentration of MIC B in the supernatant of ASCs and also sera of breast cancer and normal individuals were determined using ELISA method.
Results: The expression of MIC B in normal ASCs and Stage II ASCs was higher than Stage III ASCs. However, after treatment with IFN-γ expression of MIC B in ASCs was conversely changed as cancer ASCs showed approximately 3.5 fold higher expression of MIC B compared to normal ASCs. The mRNA expression of MIC B in Stage III, Stage II, and normal ASCs showed 61 (P = 0.02), 13 (P = 0.01) and 3 (P > 0.05) fold higher expression after stimulation with IFN-γ compared to cells with no stimulation.
Conclusion: Expression of MIC B and upregulation of this molecule in response to IFN-γ in cancer ASCs draw attention to the effective role of MSCs in the tumor microenvironment. However, more studies will be needed to further elucidate Natural-killer Group 2, member D (NKG2D) ligands-dependent immunomodulatory roles of ASCs in the tumor progression.
Keywords: Adipose-derived stem cells; breast cancer; major histocompatibility complex class I polypeptide-related sequence B; tumor microenvironment.