Subjects: Pharmaceutical Science >> Biochemistry(Drug related) submitted time 2024-06-14
Yue Jiang
Xuelian Ren
Jing Zhao
Guobin Liu
Fangfang Liu
Xinlong Guo
Ming Hao
Hong Liu
Kun Liu
He Huang
Abstract： Gemcitabine (GEM) is a potent chemotherapeutic agent widely employed in the treatment of various cancers, notably pancreatic cancer. Despite its clinical success, challenges related to GEM resistance and toxicity persist. Therefore, there is a pressing need for a deeper understanding of its intracellular mechanisms and potential targets. In this study, we utilized quantitative proteomics and thermal proteome profiling (TPP) to elucidate the effects of GEM. Our proteomic analysis revealed that GEM primarily affected DNA synthesis, leading to the upregulation of cell cycle and DNA replication proteins. Additionally, enrichment analysis highlighted the activation of the p53 pathway, shedding light on GEM-induced apoptosis mechanisms. Notably, we observed the upregulation S-phase kinase-associated protein 2 (SKP2), a cell cycle and chemoresistance regulator, in response to GEM treatment. Combining SKP2 inhibition with GEM showed synergistic effects in both cellular and animal models, suggesting SKP2 as a potential target for enhancing GEM sensitivity and overcoming chemoresistance. Furthermore, through TPP, we explored potential binding targets of GEM, which implies GEM’s broad anticancer effects. Together, these findings provide valuable insights into GEM’s molecular mechanisms and offer potential targets for improving treatment efficacy. This research holds the promise of advancing personalized treatment strategies and opening avenues for novel combination therapies to enhance outcomes in pancreatic cancer.
Subjects: Pharmaceutical Science >> Structural Biology submitted time 2024-02-21
Abstract： Bombesin receptor subtype-3 (BRS3) is an important orphan G protein-coupled receptor that regulates energy homeostasis and insulin secretion. As a member of the bombesin receptor (BnR) family, which includes neuromedin B receptor (NMBR) and gastrin-releasing peptide receptor (GRPR), the lack of known endogenous ligands and high-resolution structure has impeded understanding of BRS3 signaling and function. Here, we present cryogenic electron microscopy (cryo-EM) structures of BRS3 in complex with heterotrimeric Gq protein in three states: apo, bound to the pan-BnR agonist, BA1, and bound to the synthetic BRS3-specific agonist MK-5046. These structures reveal the architecture of the orthosteric ligand pocket underpinning molecular recognition. Comparisons with BnR members provide insights into the structural basis for BRS3’s selectivity and low affinity for bombesin peptides. Examination of conserved micro-switches suggests a shared activation mechanism among BnRs. Together our results enable deeper exploration of BRS3’s ligand selectivity, signaling, and therapeutic targeting for diabetes and obesity.
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