PDX1 Functions as a Tumor Suppressor in MCF7 Breast Cancer Cells: Implications for Chemotherapeutic Sensitivity

Background: Transcription factor pancreatic and duodenal homeobox 1 (PDX1) plays a central role in pancreatic development and insulin regulation. However, its role in breast cancer remains largely unexplored. Objective: This study investigated the effects of PDX1 knockdown and overexpression on MCF7 breast cancer cell proliferation and responsiveness to paclitaxel and doxorubicin. Methods: PDX1 knockdown and overexpression models were established in MCF7 cells. Cell viability was assessed using the XTT assay following exposure to paclitaxel (5–100 nM) or doxorubicin (125–10 µM). Gene and protein expression levels were analyzed by qRT-PCR and western blotting. Results: PDX1 knockdown in MCF7 cells led to a significant increase in proliferation compared to the scrambled control, with approximately 3.22-fold at 72 h, whereas PDX1 overexpression markedly reduced proliferation by about 2.4-fold at 72 h when compared with the control. Upon treatment with paclitaxel or doxorubicin, knockdown cells showed higher viability, indicating reduced drug sensitivity. In contrast, PDX1-overexpressing cells exhibited a significant decrease in viability after treatment with both drugs, demonstrating enhanced sensitivity. Conclusions: PDX1 exhibits tumor-suppressive properties in MCF7 cells and modulates drug response, suggesting that it may serve as a biomarker or therapeutic target in hormone receptor-positive breast cancer.