TNF-α orchestrates ADAM metallopeptidase with thrombospondin type 1 motif 2 upregulation and extracellular matrix remodeling through multimodal signaling in osteosarcoma cells

Abstract

Background: ADAMTS-2 is a key extracellular matrix (ECM) remodeling enzyme increasingly implicated in osteosarcoma biology. Although ADAMTS-2 is known to participate in collagen processing and ECM turnover, the upstream inflammatory cues and transcriptional mechanisms regulating its expression in osteosarcoma remain unclear. Tumor necrosis factor-α (TNF-α), a dominant pro-inflammatory cytokine within the osteosarcoma microenvironment, represents a strong candidate regulator due to its ability to activate several pathways. This study aimed to elucidate the TNF-α–ADAMTS-2 regulatory axis at mechanistic levels. Methods and results: Gene expression profiling revealed that ADAMTS-2 is significantly upregulated in osteosarcoma tissues compared with normal bone and is associated with ECM disassembly and collagen fibril organization pathways. Functional assays in Saos-2 cells demonstrated that TNF-α stimulation markedly increased ADAMTS-2 mRNA (~ 17-fold) and protein levels (~ twofold). Promoter activity assays showed strong TNF-α–mediated activation, with the highest induction in the − 180/ + 112 region. Pharmacological inhibition experiments revealed that MEK, PI3K, JNK, and NF-κB pathways are all required for TNF-α-induced ADAMTS-2 transcription. In silico motif analysis identified STAT3 and NF-κB binding elements within the promoter, and electrophoretic mobility shift assays supported the interaction of these transcription factors with specific promoter regions. Conclusions: This study provides the first mechanistic evidence that TNF-α regulates ADAMTS-2 expression through the coordinated activation of multiple signaling pathways and the engagement of STAT3 and NF-κB transcription factors at the promoter. These findings uncover a previously uncharacterized inflammatory regulatory axis linking TNF-α signaling to ECM remodeling and highlight ADAMTS-2 as a potential mediator of osteosarcoma progression.