Clinical studies have suggested that tirzepatide may also possess hepatoprotective effects; however, the molecular mechanisms underlying this association remain unclear. In our study, we performed biochemical analyses of serum and histopathological examinations of liver tissue in mice. To preliminarily explore the molecular mechanisms of tirzepatide on metabolic dysfunction-associated fatty liver disease (MAFLD), liquid chromatography-mass spectrometry (LC-MS) was employed for comprehensive metabolomic, lipidomic, and proteomic analyses in MAFLD mice fed a high-fat diet (HFD). The results demonstrated that tirzepatide significantly reduced serum levels of alanine transaminase (ALT) and aspartate transaminase (AST), as well as hepatic triglycerides (TG) and total cholesterol (TC), indicating its efficacy in treating MAFLD. Further findings revealed that tirzepatide reduced fatty acid uptake by downregulating Cd36 and Fabp2/4, as well as enhance the mitochondrial-lysosomal function by upregulating Lamp1/2. In addition, tirzepatide promoted cholesterol efflux and reduced cholesterol reabsorption by upregulating the expression of Hnf4a, Abcg5, and Abcg8. These results suggest that tirzepatide exerts its therapeutic effects on MAFLD by reducing fatty acid uptake, promoting cholesterol excretion, and enhancing mitochondrial-lysosomal function, providing a theoretical basis for a comprehensive understanding of tirzepatide.

Objectives: ABCB1-mediated multidrug resistance (MDR) compromises chemotherapy efficacy in colorectal cancer (CRC). Despite decades of research, no selective ABCB1 inhibitor has achieved clinical success. This study investigates ML210 as a novel ABCB1-specific inhibitor to reverse ABCB1-driven MDR. Methods: Cytotoxicity assays (MTT) were performed on ABCB1-overexpressing HCT-8/V and ABCG2-overexpressing S1-M1-80 CRC cells. Drug accumulation (doxorubicin/mitoxantrone) was quantified via flow cytometry, and cell cycle effects were analyzed using propidium iodide staining. Molecular docking utilized the ABCB1 crystal structure. Results: ML210 selectively reversed ABCB1-mediated resistance to doxorubicin and vincristine in HCT-8/V cells, enhancing intracellular drug accumulation without affecting ABCG2 activity. It induced cell cycle arrest in ABCB1-overexpressing cells and did not alter ABCB1 protein expression. Molecular docking revealed stable binding of ML210 within the ABCB1 substrate pocket through hydrophobic interactions and hydrogen bonding. Conclusions: ML210 is a selective ABCB1 inhibitor that circumvents MDR via direct transport blockade, offering a targeted strategy against ABCB1-mediated chemoresistance in CRC. Its specificity for ABCB1 over ABCG2 highlights potential clinical advantages.

Background: Estrogen receptor-positive (ER+) breast cancer accounts for two-thirds of all breast cancers, and its early and late recurrences still threaten patients’ long-term survival and quality of life. Finding candidate tumor antigens and potential therapeutic targets is critical to addressing these unmet needs. Method: The isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis was employed to identify the differentially expressed proteins (DEPs) between ER + breast cancer and corresponding adjacent normal tissue. Candidate DEPs were screened by bioinformatic analyses, and their expression was confirmed by immunohistochemical (IHC) staining and western blot. A series of in vitro experiments, including wound healing assay, colony formation, and cell cycle assay, were performed to reveal the functions of selected DEPs. Additionally, their clinical significances were further analyzed. Result: A total of 369 DEPs (fold change ≥ 2.0 or ≤ 0.66, P < 0.05) were discovered. Compared with normal tissue, 358 proteins were up-regulated and 11 proteins were down-regulated in ER + breast cancer. GO and KEGG enrichment analysis showed that DEPs were closely associated with RNA regulation and metabolic pathways. STRING analysis found ESF1 and MIPEP were the hub genes in breast cancer, whose increased expressions were verified by the IHC staining and western blot. Knocking down ESF1 and MIPEP inhibited colony formation and increased cell apoptosis. Besides, knocking down ESF1 inhibited wound healing but not MIPEP. In addition, ESF1 and MIPEP expression were negatively associated with patient prognosis. Conclusion: The upregulation of ESF1 and MIPEP promoted ER + breast cancer proliferation, which might provide novel targets for the development of new therapies.