Potentiated Effects of Photobiomodulation and Celecoxib on the Epithelial–Mesenchymal Transition Signaling of <i>E-Cadherin</i> , <i>N-Cadherin</i> , <i>α-SMA</i> in Breast Cancer Cells, MCF7, and MDA-MB-231

<b><i>Background and Objective:</i></b> Breast cancer (BC) is one of the most common cancers among women, with a high potential for metastasis. The epithelial-mesenchymal transition (EMT) is crucial in the invasion and metastasis of cancer cells. This research was designed to examine the efficacy of photobiomodulation therapy in combination with celecoxib in inhibiting the EMT process. We also analyzed the changes in the expression of <i>E-cadherin</i>, <i>N-cadherin</i>, and <i>α-SMA</i> genes in BC cell lines MCF-7 and MDA-MB-231. <b><i>Material and Methods:</i></b> In this study, the IC₅₀ of celecoxib was first determined using the 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide assay for both cell lines. The cells were then treated with celecoxib, laser irradiation, and their combination. A migration assay was performed to evaluate the cell migration. Real-time polymerase chain reaction also assessed the changes in the expression of the abovementioned genes. <b><i>Results:</i></b> A combination of celecoxib and laser therapy significantly reduced the migration of cancer cells. Additionally, the potentiated effect of the combined therapy altered the expression levels of the aforementioned genes, indicating the potential role of the combination treatment in regulating EMT. <b><i>Conclusions:</i></b> Our research discloses that combining laser therapy with celecoxib could serve as an effective therapeutic approach to inhibit BC invasion and metastasis by targeting the EMT process and decelerating disease progression. Further investigations are essential to validate these results in clinical environments.