Impact of siRNA-mediated tissue inhibitor of metalloproteinases-1 knockdown on proliferation and apoptosis in triple-negative breast cancer: bioinformatics and experimental insights.

Abstract

Breast cancer remains a significant global health concern, with its molecular intricacies and the mechanistic role of tissue inhibitor of metalloproteinases-1 (TIMP1) still poorly understood. This study employed an integrated approach combining bioinformatic analyses and primary experimental validations to discover the complexities surrounding TIMP1 in breast cancer. Bioinformatic tools such as pan-cancer view, mRNA expression analysis, immune infiltrations, pathway enrichment, and functional annotations provided a clear perspective on TIMP1 in breast cancer. Gene expression by qPCR analysis for TIMP1 were conducted in MCF-7 and MDA-MB-231 and T47D cells and compared to normal breast cells, MCF-10A. Bioinformatic platform, The University of Alabama at Birmingham Cancer (UALCAN) data analysis underscored the diagnostic relevance of TIMP1, showing its upregulated mRNA expression across different stages and metastatic properties. Notably, the impact of breast cancer on immune cells was explored, revealing a direct influence of TIMP1 on CD4⁺, CD8⁺, and B cells, with strong correlations were observed. Kaplan-Meier (KM) survival analysis revealed that high TIMP1 expression correlates with poor prognosis in breast cancer patients, reinforcing its oncogenic potential. Furthermore, immunohistochemistry supported these findings, and protein-protein interaction analysis through STRING and CYTOSCAPE identified interconnected genes linked to TIMP1 in breast cancer. Enriched pathway analysis using KEGG pathways unveiled the potential involvement of TIMP1 in the phosphatidylinositol 3-kinases (PI3K) pathway and cell cycle regulation, further substantiating its oncogenic role. Experimental validation through siRNA silencing TIMP1 reduces cell growth and promotes G1 phase cell cycle arrest in MDA-MB-231 cells. In conclusion, this comprehensive study suggests that targeting TIMP1 in breast cancer could present a promising avenue for therapeutic development, highlighting its potential as a crucial player in the molecular landscape of breast cancer progression.