Cellular & Molecular Biology Letters最新文献

Background: Patients with castration-resistant prostate cancer (CRPC) often develop resistance following long-term enzalutamide treatment. Building upon previous research, we aims to further explore the effect of ilicicolin A (ili-A) on enzalutamide resistance and to elucidate the underlying resistance mechanisms.

Methods: Proliferation, migration, and invasion of prostate cancer (PCa) cells were evaluated by 5-ethynyl-2'-deoxyuridine (EdU) assays, colony formation, scratch, and Transwell. Cell Counting Kit 8 (CCK-8) was used to assess the efficacy of drug inhibition in CRPC cells. The expression of tumor cell apoptotic proteins and ferroptosis was assessed using western blot (WB) analysis. Coimmunoprecipitation (Co-IP) and proximity ligation assay (PLA) were used to identify the mechanism of interaction between ilicicolin A and ferroptosis. Tumor transplantation experiments with mice were conducted to confirm findings.

Results: Ili-A showed dose-dependent inhibition of PCa cells including C4-2B and 22Rv1 cell lines. The overexpression of the RORC gene activated the expression of ferroptosis-related proteins, such as FTH1, GPX4 and SLC7A11, and enhanced proliferation of PCa cells. WB experiments indicated that RORC upregulated AR and AR-V7. An enzalutamide-resistant C4-2B cell line revealed that RORC serves as a gene target for enzalutamide resistance. Finally, it was observed that ili-A could suppress CRPC cells proliferation by downregulating RORC expression, thereby promoting ferroptosis and enhancing the sensitivity to enzalutamide.

Conclusions: Ili-A inhibited RORC expression, increased malondialdehyde (MDA) content, suppressed glutathione (GSH) production, released free Fe²⁺, increased reactive oxygen species (ROS), activated the ferroptosis pathway, enhanced enzalutamide sensitivity, and inhibited CRPC cell proliferation. Furthermore, ili-A enhances the interaction between ROR-γ and GPX4.

Inhibition of the phosphatidylinositol kinase vacuolar protein sorting 34 (VPS34) with the pharmacological compound VPS34-IN1 has a range of effects on the dynamics of endosomes. While VPS34 inhibition has been previously suggested as a potential therapeutic approach for treating certain cancers, our findings indicate that it has minimal cytotoxic effects on the leukemic blastic plasmacytoid dendritic cell neoplasm (BPDCN) CAL-1. However, we also found that VPS34-IN1 interferes with the function of this plasmacytoid dendritic cell (pDC) line, by inhibiting Toll-like receptor (TLR)7 signaling. In contrast, VPS34-IN1 triggers activation of the stimulator of interferon genes (STING) and significantly enhances cellular response to the STING agonist 2'3'-cyclic guanosine monophosphate-adenosine monophosphate (2'3'-cGAMP) with increased expression of type I interferons (IFNs). Inhibition of protein synthesis by VPS34-IN1 appears to be central to this synergy with STING activation. Thus, despite their limited toxicity toward different cancer lines, VPS34-IN1 may represent a promising compound to promote expression of type I IFNs and thus antitumoral immunity.

Background: Angiogenesis, the formation of new blood vessels from preexisting vasculature, is often impaired in pathological conditions, such as a hyperglycemic environment. Angiogenesis is tightly regulated by a balance of proangiogenic and antiangiogenic factors. CD93, a glycoprotein expressed on endothelial cells (ECs), has been identified as a significant proangiogenic factor. However, the specific impact of its glycosylation, particularly O-GlcNAcylation, on endothelial cell function and angiogenesis remains entirely unexplored. Therefore, this study aimed to elucidate the role of CD93 glycosylation in angiogenesis and uncover the underlying molecular mechanism, especially under high glucose conditions.

Methods: siCD93 was used to evaluate the role of CD93 in endothelial cell angiogenesis. Tube formation, spheroid sprouting assays, Transwell assays, and adhesion assays were used to assess the angiogenic capability, migration, and adhesion, respectively. Co-immunoprecipitation coupled with mass spectrometry (Co-IP-MS) was employed to identify CD93-interacting proteins. A murine dorsal skin wound model was used to elucidate its role in angiogenesis during wound healing.

Results: siCD93 significantly impaired angiogenesis by inhibiting migration and adhesion without affecting proliferation or cell cycle in ECs. CD93 O-GlcNAcylation modulated its proangiogenic function, whereas high-glucose treatment downregulated both CD93 expression and its O-GlcNAcylation. CD93 overexpression partially rescued the angiogenic impairment induced by high glucose. In vivo studies further indicated that CD93 knockout exacerbated wound healing delay in diabetic wounds. Mechanistically, heat shock protein 90 (HSP90) interacted with the extracellular domain of CD93 to stabilize CD93 O-GlcNAcylation and protect it from ubiquitin-proteasomal degradation. The HSP90-CD93 interaction enabled CD93 to activate the downstream focal adhesion kinase (FAK) signaling pathway, thereby promoting angiogenesis. In vivo experiments further confirmed that HSP90 inhibition impaired the proangiogenic effects of recombinant CD93 protein (rCD93) in skin wound healing.

Conclusions: CD93 promotes angiogenesis dependent on O-GlcNAcylation. Under high glucose, CD93 expression and its O-GlcNAcylation are downregulated, leading to impaired angiogenesis. Mechanistically, HSP90 interacts with CD93 to stabilize it against ubiquitin-proteasomal degradation, thereby maintaining O-GlcNAcylation homeostasis and activating the downstream FAK signaling pathway. Our findings identify the HSP90-CD93 interaction as a potential therapeutic target for angiogenesis-related disorders.