expression modulation of immune checkpoint molecules by ibrutinib and everolimus through stat3 in mcf-7 breast cancer cells

Tumor-targeted therapy with small-molecule inhibitors (smis) has been demonstrated to be a highly effective therapeutic strategy for various cancers. however, their possible associations with immune evasion mechanisms remain unknown. this study examined the association of inhibitors of the protein kinase b (akt), mammalian target of rapamycin (mtor), and bruton’s tyrosine kinase (btk) signaling pathways with the expression of immune checkpoint ligands programmed death-ligand 1 (pd-l1), cd155, and galectin-9 (gal-9) in a breast cancer cell line. mcf-7 cells were treated with everolimus, mk-2206, and ibrutinib. an mtt assay was used to determine the optimal dose for all drugs. a real-time polymerase chain reaction was utilized to measure the mrna expression of pd-l1, cd155, and gal-9. the western blot technique was also employed to evaluate the protein expression of the phosphorylated signal transducer and activator of transcription 3 (stat3). the optimal doses of everolimus, mk-2206, and ibrutinib were observed to be 200, 320, and 2000 nm, respectively. the pd-l1 and cd155 mrna expression was significantly decreased following the treatment with everolimus and ibrutinib, but not with mk-2206. there were no differences in gal-9 expression between the single-treated and control groups; however, combined treatment with everolimus and ibrutinib increased its mrna expression. everolimus and ibrutinib both inhibited constitutive stat3 phosphorylation in mcf-7, which was more pronounced in combination treatment. the findings regarding the modulation of pd-l1, cd155, and gal-9 molecules by smis emphasize the crosstalk between the expression of these immune checkpoint molecules and akt/mtor/btk signaling pathways through stat3 as a critical transcription factor.