bims-prolim 2025-05-18 papers

bims-prolim

Biomed News

on Protein lipidation, metabolism and cancer

Issue of 2025–05–18
seven papers selected by
Bruna Martins Garcia, CABIMER

O-GlcNAcylation of epidermal growth factor receptor and glucose transporter 1 prevents their intrinsic down regulation in breast cancer cells.
Data-Driven Proteomics for Post-Translational Modification Discovery.
Acid sphingomyelinase recruits palmitoylated CD36 to membrane rafts and enhances lipid uptake.
OGT Enhances Adriamycin Resistance of Breast Cancer by Promoting Glycolysis through MDM4 Upregulation in an O-GlcNAcylation-Dependent Manner.
Mechanical effect of protein glycosylation on BiP-mediated post-translational translocation and folding in the endoplasmic reticulum.
OGT-regulated O-GlcNAcylation promotes the malignancy of colorectal cancer by activating STAT2 to induce macrophage M2: OGT protein macromolecule action.
Targeting GPX4 palmitoylation to boost antitumor immunity.

Biochem Cell Biol. 2025 May 14.

O-GlcNAcylation of epidermal growth factor receptor and glucose transporter 1 prevents their intrinsic down regulation in breast cancer cells.

G Pauline Padilla-Meier, Yeshika Bhatia, Suresh Mishra.

The hexosamine biosynthetic pathway (HBP) is upregulated in many cancer cell types leading to upregulation of post-translational modification of proteins by β-N-acetyglucosamine (O-GlcNAc), the product of HBP. However, our knowledge of the identity of proteins that undergo O-GlcNAcylation in cancer cells and consequently their roles is very limited. We investigated the O-GlcNAcylation of epidermal growth factor receptor (EGFR) and glucose transporter 1 (GLUT1) in T47D and MDA-MB-231 breast cancer cell models. We examined the effect of the loss of putative O-GlcNAcylation sites in EGFR and GLUT1 on cell signaling pathways and their functional consequences on cell cycle progression and cell metabolism using FACS analysis and in vitro assays. EGFR and GLUT1 undergo O-GlcNAcylation in T47D and MDA-MB-231 breast cancer cells, which enhances their functions and prevents their intrinsic downregulation. This appears to involve an interplay between phosphorylation, O-GlcNAcylation and ubiquitination in both proteins. Importantly, perturbing the putative O-GlcNAcylation sites in both proteins adversely affected their stability, functions, and metabolic status of breast cancer cells, including glucose uptake and lactate production. In conclusion, the reprogrammed metabolism in cancer cells extends beyond energy and macromolecule requirements and contributes to cell-signaling events that support the stability and function of cancer promoting proteins.

DOI: https://doi.org/10.1139/bcb-2025-0055
Proteomics. 2025 May;25(9-10): e202500064

Data-Driven Proteomics for Post-Translational Modification Discovery.

Van-Nui Nguyen, Nguyen Quoc Khanh Le.

DOI: https://doi.org/10.1002/pmic.202500064
J Biol Chem. 2025 May 08. pii: S0021-9258(25)02062-9. [Epub ahead of print] 110213

Acid sphingomyelinase recruits palmitoylated CD36 to membrane rafts and enhances lipid uptake.

Meng Ding, Yun Zhang, Xiaoting Xu, Yuan Zhu, Hui He, Tianyu Jiang, Yashuang Huang, Wenfeng Yu, Hailong Ou.

  CD36 palmitoylation increases its membrane localization and is required for CD36-mediated uptake of oxidized low-density lipoprotein (oxLDL). Acid sphingomyelinase (ASMase) is transported to the plasma membrane, where it promotes lipid raft clustering, facilitating membrane protein anchoring for biological functions. We here investigated the effects of oxLDL on CD36 palmitoylation and explored the role of ASMase in CD36 membrane translocation. We found that oxLDL increased CD36 palmitoylation and drives its intracellular trafficking from the endoplasmic reticulum to plasma membrane lipid rafts in macrophages. Affinity purification followed by mass spectrometry analysis identified CD36 bound to ASMase in plasma membrane. The CD36/ASMase binding was enhanced by oxLDL treatment. Genetic ablation and pharmacological inhibition of ASMase reduced CD36 recruitment to lipid rafts, and inhibited CD36 intracellular signaling and lipid uptake. Moreover, inhibiting Sortilin to block ASMase intracellular trafficking and reduce membrane ASMase also caused a sharp decrease in amount of membrane CD36. In addition, ASMase overexpression dramatically promoted palmitoylated CD36 membrane localization but not CD36 without palmitoylation, in which the modification was inhibited by 2-bromopalmitate (2-BP) treatment or point mutation at the palmitoylation site. Moreover, ASMase knockout inhibited CD36 membrane recruitment both in peritoneal macrophages and in aorta, and attenuated lipid accumulation in atherosclerotic plaques in mice. Finally, we found oxLDL activated extracellular signal-regulated kinase1/2 (ERK1/2)/specificity protein (SP1) signaling, upregulating ASMase transcription and promoting sphingomyelin catabolism. Therefore, these data demonstrate that ASMase expression induced by oxLDL is required for palmitoylated CD36 membrane translocation during foam cell formation in macrophages.

Keywords:  CD36; acid sphingomyelinase; foam cell; lipid raft; palmitoylation

DOI:  https://doi.org/10.1016/j.jbc.2025.110213
Biochem Genet. 2025 May 15.

OGT Enhances Adriamycin Resistance of Breast Cancer by Promoting Glycolysis through MDM4 Upregulation in an O-GlcNAcylation-Dependent Manner.

Xiang Liu, Sihao Huang, Kuangye Zhu, Ludi Du.

  Adriamycin (ADR) is a chemotherapy drug for breast cancer, and its resistance is a major obstacle in the clinical treatment of breast cancer. O-GlcNAcylation is a post-translational modification that impacts chemotherapy resistance in cancers. This present study aims to investigate the mechanism of O-GlcNAcylation-mediated ADR resistance in breast cancer. Cell viability, proliferation, and apoptosis were performed to evaluate ADR resistance in breast cancer cells. O-GlcNAcylation, OGA and OGT levels in patients, and breast cancer cells resistant to ADR or not were detected by western blot and quantitative real-time PCR. Glycolysis of ADR-resistant cells was evaluated by measurement of glucose and lactic acid levels, and extracellular acidification rate and oxygen consumption rate. The underlying mechanism was explored by western blot and pathway enrichment analysis. Effects of OGT in vivo were assessed by xenograft tumor model. Results showed that OGT protein and mRNA levels were increased in MCF-7R and BT-549R cells and tumors of ADR-resistant patients with breast cancer. Moreover, O-GlcNAcylation was increased in ADR-resistant breast cancer cells. OGT knockdown inhibited glycolysis and O-GlcNAcylation and protein level of MDM4 at S96 site. Notably, MDM4 overexpression restored glycolysis in MCF-7R and BT-549R cells inhibited by OGT knockdown. Additionally, OGT knockdown inhibited tumor growth in vivo. Collectively, this study demonstrated that OGT promote breast cancer resistant to ADR through facilitating glycolysis in breast cancer cells by O-GlcNAcylation on MDM4. This study may provide a target for overcoming ADR resistance in breast cancer.

Keywords:  Adriamycin resistant; Breast cancer; Glycolysis; MDM4; O-GlcNAcylation; OGT

DOI:  https://doi.org/10.1007/s10528-025-11129-9
Biophys Rev. 2025 Apr;17(2): 435-447

Mechanical effect of protein glycosylation on BiP-mediated post-translational translocation and folding in the endoplasmic reticulum.

Christian A M Wilson, Hilda M Alfaro-Valdés, Merve Kaplan, Cecilia D'Alessio.

  About one-third of the proteins synthesized in eukaryotic cells are directed to the secretory pathway, where close to 70% are being N-glycosylated. N-glycosylation is a crucial modification for various cellular processes, including endoplasmic reticulum (ER) glycoprotein folding quality control, lysosome delivery, and cell signaling. The defects in N-glycosylation can lead to severe developmental diseases. For the proteins to be glycosylated, they must be translocated to the ER through the Sec61 translocon channel, either via co-translationally or post-translationally. N-glycosylation not only could accelerate post-translational translocation but may also enhance protein stability, while protein folding can assist in their movement into the ER. However, the precise mechanisms by which N-glycosylation and folding influence translocation remain poorly understood. The chaperone BiP is essential for post-translational translocation, using a "ratchet" mechanism to facilitate protein entry into the ER. Although research has explored how BiP interacts with protein substrates, there has been less focus on its binding to glycosylated substrates. Here, we review the effect of N-glycosylation on protein translocation, employing single-molecule studies and ensembles approaches to clarify the roles of BiP and N-glycosylation in these processes. Our review explores the possibility of a direct relationship between translocation and a ratchet effect of glycosylation and the importance of BiP in binding glycosylated proteins for the ER quality control system.
Supplementary Information: The online version contains supplementary material available at 10.1007/s12551-025-01313-x.

Keywords:  BiP Chaperone; ER translocation; Protein N-glycosylation; Ratchet mechanism

DOI:  https://doi.org/10.1007/s12551-025-01313-x
Int J Biol Macromol. 2025 May 08. pii: S0141-8130(25)04609-4. [Epub ahead of print] 144057

OGT-regulated O-GlcNAcylation promotes the malignancy of colorectal cancer by activating STAT2 to induce macrophage M2: OGT protein macromolecule action.

Meng Wang, Li Qiao, Li Jin, Yuanyuan Chen, Xing Wen, Haijuan Wang.

  O-GlcNAcylation, as an important glycosylation modification, plays a key role in cancer progression. The purpose of this study was to investigate the role of OGT (O-GlcNAc transferase) in the regulation of O-GlcNAcylation and macrophage M2 polarization, especially in the malignant progression of cancer. The expression of OGT in COAD (colorectal adenocarcinoma) was identified by bioinformatics analysis, and its function was detected by cell culture and stimulation techniques. The OGT expression system was constructed by plasmid construction and cell transfection, and the expression changes of OGT and related genes were analyzed by RNA extraction and quantitative real-time PCR (qRT-PCR). Western blot was used to detect protein expression, transmission electron microscopy (TEM) was used to observe cell ultrastructure, and EdU staining, CCK-8 method, wound healing test, Transwell migration and invasion test were used to evaluate cell proliferation and migration. Immunofluorescence staining was used to detect intracellular markers, and the interaction between OGT and STAT2 was analyzed by co-immunoprecipitation (Co-IP) and ubiquitination experiments. Finally, statistical analysis was performed to evaluate the significance of the experimental results. We found that OGT is highly expressed in COAD and promotes M2-type polarization of macrophages through exosomes derived from colorectal cancer. In M2-type tumor-associated macrophages (TAMs), the synergistic effect of OGT and the deubiquitination enzyme USP18 promoted the deubiquitination of STAT2, thereby enhancing the degree of M2 polarization.

Keywords:  Cancer; Macrophage M2; O-GlcNAcylation; OGT protein macromolecule; STAT2

DOI:  https://doi.org/10.1016/j.ijbiomac.2025.144057
Trends Cancer. 2025 May 14. pii: S2405-8033(25)00121-9. [Epub ahead of print]

Targeting GPX4 palmitoylation to boost antitumor immunity.

Daehee Hwang, Whitney S Henry.

  Despite significant milestones in cancer immunotherapy, tumor cells often escape immune surveillance. Zhou et al. revealed that the pivotal ferroptosis suppressor glutathione peroxidase 4 (GPX4) can undergo palmitoylation by zDHHC8, enhancing ferroptosis resistance. This study highlights the potential of targeting GPX4 palmitoylation to enhance cytotoxic T cell-mediated ferroptosis of tumor cells.

Keywords:  GPX4; ferroptosis; immune-checkpoint blockade (ICB); palmitoylation; tumor microenvironment (TME); zDHHC8

DOI:  https://doi.org/10.1016/j.trecan.2025.05.001