TIPE regulates glucometabolic reprogramming by modulating LDHA expression in triple-negative breast cancer

Background and purpose: Tumor necrosis factor alpha-induced protein 8 (TNFAIP8), also called TIPE, plays critical regulatory roles in various malignancies, yet its molecular mechanisms in metabolic reprogramming of triple-negative breast cancer (TNBC) remain elusive. This study aimed to elucidate how TIPE regulates the expression of the glycolytic key enzyme lactate dehydrogenase A to influence TNBC cell proliferation and glycolytic reprogramming, thereby providing potential molecular targets for TNBC therapy. Methods: Stable TIPE-knockdown MDA-MB-231 cell lines were established using a lentiviral shRNA system and selected with puromycin. Transcriptome sequencing was used to analyze TIPE's impact on TNBC glycolytic pathways. Extracellular acidification rate (ECAR) was measured using the Seahorse XF Analyzer, complemented by lactate production assays to evaluate glycolytic capacity. Co-IP/MS was carried out to identify TIPE-interacting proteins, with subsequent validation of TIPE-LDHA interaction through co-transfection of TIPE-Myc and LDHA-Flag plasmids in HEK-293T cells. Protein stability was assessed via cycloheximide (CHX) chase and ubiquitination assays. The cell counting kit-8 (CCK-8) assay and animal experiments (Approval Number for Animal Ethics: 202212007) were conducted to investigate how TIPE affects the proliferation and glucometabolic reprogramming of TNBC by mediating LDHA. Results: TIPE promoted glycolytic metabolic reprogramming in TNBC. Knockdown of TIPE significantly inhibited TNBC glycolytic activity and glycolytic capacity (P<0.001). TIPE interacted with the key glycolytic enzyme LDHA and suppressed its degradation rate through a ubiquitination-dependent mechanism. Cellular experiments demonstrated that TIPE mediated LDHA to enhance TNBC cell proliferation (P<0.001) and glycolytic activity (P<0.001). Animal studies confirmed that TIPE knockdown significantly suppressed tumor volume (P<0.05) and weight (P<0.01), with a positive correlation between TIPE and LDHA expression levels in tumor tissues. Conclusion: TIPE enhances TNBC cell proliferation and glycolytic capacity by inhibiting LDHA ubiquitination-mediated degradation.