O-GlcNAcylation enhances the invasion of thyroid anaplastic cancer cells partially by PI3K/Akt1 pathway

O-GlcNAcylation-related genes mediate tumor microenvironment characteristics and prediction of immunotherapy response in gastric cancer

We aim to identify molecular clusters related to O-GlcNAcylation and establish a novel scoring system for predicting prognosis and immunotherapy efficacy in patients with gastric cancer (GC). The transcriptomic and clinical data are obtained from XENA-UCSC and GEO databases. The O-GlcNAcylation-related genes are obtained from the GSEA database. Consensus clustering analysis is employed to identify O-GlcNAcylation-related molecular clusters, and principal component analysis (PCA) is utilized to develop a novel prognostic scoring system for predicting GC outcomes and immunotherapy efficacy. The prognostic accuracy of the scoring system is assessed across five real-world cohorts. The biological function of actin alpha 2, smooth muscle (ACTA2) in GC is determined through experimental verification. Using 34 O-GlcNAcylation-related genes associated with prognosis in GC patients, these individuals are divided into two distinct subgroups characterized by different outcomes, tumor microenvironment profiles, and clinical case characteristics. The DEGs between the two subgroups are subsequently used to further divide the GC patients into two subgroups by consensus cluster analysis. PCA is used to construct a prognostic scoring system, which reveal that patients in the low-score subgroup have a better prognosis and greater benefit from immunotherapy. The accuracy of the scoring system is confirmed through validation in a cohort of patients receiving immunotherapy in the real world. ACTA2 promotes proliferation and inhibits apoptosis in GC cells. These findings suggest that we successfully establish molecular clusters associated with O-GlcNAcylation and develop a scoring system that demonstrates strong performance in predicting the prognosis of patients with GC and the effect of immunotherapy interventions.

Posttranslational Modifications in Thyroid Cancer: Implications for Pathogenesis, Diagnosis, Classification, and Treatment

There is evidence that posttranslational modifications, including phosphorylation, acetylation, methylation, ubiquitination, sumoylation, glycosylation, and succinylation, may be involved in thyroid cancer. We review recent reports supporting a role of posttranslational modifications in the tumorigenesis of thyroid cancer, sensitivity to radioiodine and other types of treatment, the identification of molecular treatment targets, and the development of molecular markers that may become useful as diagnostic tools. An increased understanding of posttranslational modifications may be an important supplement to the determination of alterations in gene expression that has gained increasing prominence in recent years.

Hypermethylation of DLG3 Promoter Upregulates RAC1 and Activates the PI3K/AKT Signaling Pathway to Promote Breast Cancer Progression

Objective

This investigation aimed to figure out the relation between discs large homolog 3 (DLG3) expression and the progression and prognosis of breast cancer (BC).

Methods

qRT-PCR was utilized for confirming DLG3 expression and RAC1 mRNA expression in BC tissues and cells. Subsequently, after overexpression or interference of DLG3, the changes of the biological activities of BC cells, including cell proliferation, migration, invasion, and apoptosis, were detected through CCK-8, colony formation assay, wound healing assay, transwell assay, and flow cytometry, respectively. Furthermore, western blotting was utilized to measure the protein expression of DLG3 and RAC1, as well as related proteins of epithelial-mesenchymal transition (EMT) and the PI3K/AKT signaling pathway.

Results

At both cellular and tissue level in BC, DLG3 was downregulated and methylation level was upregulated; RAC1 showed an opposite change and was of a negative correlation with DLG3. In MCF-7 and HCC1937, we found that the upregulation of DLG3 could inhibit RAC1 expression as well as cell proliferation, invasion, migration, and EMT, while promoting apoptosis. Also, DLG3 inhibited the activation of the P13K/AKT pathway.

Conclusion

Hypermethylation of DLG3 promoter upregulates RAC1 and activates the PI3K/AKT pathway, thus promoting BC progression. This conclusion provides ideas and experimental basis for improving and treating BC patients.

OGT regulated O-GlcNAcylation promotes papillary thyroid cancer malignancy via activating YAP

The incidence of thyroid cancer is growing rapidly during the past decades worldwide. Although most thyroid tumors are curable, some patients diagnosed with distant metastases are associated with poor prognosis. The molecular mechanisms underlying these cases are still largely unknown. Here we found that the upregulated O-Linked N-Acetylglucosamine Transferase (OGT) expression and O-GlcNAcylation (O-GlcNAc) modification in papillary thyroid cancer (PTC) were essential in tumor growth and metastasis. Mass spectrometry analysis showed that YAP was the effector protein modified by OGT. In details, YAP Ser109 O-GlcNAcylation promoted the malignant phenotypes in PTC cells by inducing YAP Ser127 dephosphorylation and activation. Our work clearly showed the critical role of OGT and YAP played in PTC tumors and made it possible for us to seek the clinical potential of manipulating OGT/YAP activity in PTC targeted therapies. These findings also confirmed OGT worked in collaboration with classical Hippo pathway kinases as an upstream regulator of YAP in PTC tumors.

Icariin Mitigates the Growth and Invasion Ability of Human Oral Squamous Cell Carcinoma via Inhibiting Toll-Like Receptor 4 and Phosphorylation of NF-κB P65

BACKGROUND

Oral squamous cell carcinoma (OSCC) is an aggressive malignancy worldwide. Icariin (ICA), an active ingredient of flavonoids, has been demonstrated to possess antitumor activity in diverse cancers. Whereas, the role of ICAin OSCC is still unclear.

METHODS

Herein, we investigated the anti-tumor effects of ICA in vitro and in vivo. CCK-8, colony formation and trans-well assay were used to examined viability, proliferation and invasion in SCC-9 and SCC-15 cell lines, respectively. Next, we tested the expression of toll-like receptor 4 (TLR4) and NF-κB P65 by western blot or immunofluorescence staining. Finally, we constructed a xenograft mice model to investigate the effect of ICA in vivo.

RESULTS

In vitro, ICA decreased the human oral squamous cells viability, proliferation and invasion in a concentration-dependent manner. Besides, ICA decreased the phosphorylation level of P65 and down-regulated TLR4 protein. In vivo, compared with control, ICA significantly suppressed the tumor size and weight. In addition, ICA downregulated the levels of Ki67 and VEGF markedly. Dramatically, ICA decreased the phosphorylation level of P65 in tumor tissues.

CONCLUSION

Taken together, ICA could act as a anticancer drug against OSCC to mitigate the growth and invasion ability, the underlying mechanism may due to the down-regulation of TLR4/NF-κB signaling.

O-GlcNAcylation mediates metastasis of cholangiocarcinoma through FOXO3 and MAN1A1

The leading cause of death in cancer patients is metastasis, for which an effective treatment is still necessary. During metastasis, cancer cells aberrantly express several glycans that are correlated with poor patient outcome. This study was aimed toward exploring the effects of O-GlcNAcylation on membranous N-glycans that are associated with the progression of cholangiocarcinoma (CCA). Global O-GlcNAcylation in CCA cells was depleted using specific siRNA against O-GlcNAc transferase (OGT), which transfers GlcNAc to the acceptor proteins. Using an HPLC-Chip/Time-of-Flight (Chip/TOF) MS system, the N-glycans associated with O-GlcNAcylation were identified by comparing the membranous N-glycans of siOGT-treated cells with those of scramble siRNA-treated cells. In parallel, the membranous N-glycans of the parental cells (KKU-213 and KKU-214) were compared with those of the highly metastatic cells (KKU-213L5 and KKU-214L5). Together, these data revealed that high mannose (Hex₉HexNAc₂) and biantennary complex (Hex₅HexNAc₄Fuc₁NeuAc₁) N-linked glycans correlated positively with metastasis. We subsequently demonstrate that suppression of O-GlcNAcylation decreased the expression of these two N-glycans, suggesting that O-GlcNAcylation mediates their levels in CCA. In addition, the ability of highly metastatic cells to migrate and invade was reduced by the presence of Pisum Sativum Agglutinin (PSA), a mannose-specific lectin, further indicating the association of high mannose type N-glycans with CCA metastasis. The molecular mechanism of O-GlcNAc-mediated progression of CCA was shown to proceed via a series of signaling events, involving the activation of Akt/Erk (i), an increase in FOXO3 phosphorylation (ii), which results in the reduction of MAN1A1 expression (iii) and thus the accumulation of Hex₉HexNAc₂ N-glycans (iv). This study demonstrates for the first time the association between O-GlcNAcylation, high mannose type N-glycans, and the progression of CCA metastasis, suggesting a novel therapeutic target for treatment of metastatic CCA.

O-GlcNAc in cancer: An Oncometabolism-fueled vicious cycle

Cancer cells exhibit unregulated growth, altered metabolism, enhanced metastatic potential and altered cell surface glycans. Fueled by oncometabolism and elevated uptake of glucose and glutamine, the hexosamine biosynthetic pathway (HBP) sustains glycosylation in the endomembrane system. In addition, the elevated pools of UDP-GlcNAc drives the O-GlcNAc modification of key targets in the cytoplasm, nucleus and mitochondrion. These targets include transcription factors, kinases, key cytoplasmic enzymes of intermediary metabolism, and electron transport chain complexes. O-GlcNAcylation can thereby alter epigenetics, transcription, signaling, proteostasis, and bioenergetics, key 'hallmarks of cancer'. In this review, we summarize accumulating evidence that many cancer hallmarks are linked to dysregulation of O-GlcNAc cycling on cancer-relevant targets. We argue that onconutrient and oncometabolite-fueled elevation increases HBP flux and triggers O-GlcNAcylation of key regulatory enzymes in glycolysis, Kreb's cycle, pentose-phosphate pathway, and the HBP itself. The resulting rerouting of glucose metabolites leads to elevated O-GlcNAcylation of oncogenes and tumor suppressors further escalating elevation in HBP flux creating a 'vicious cycle'. Downstream, elevated O-GlcNAcylation alters DNA repair and cellular stress pathways which influence oncogenesis. The elevated steady-state levels of O-GlcNAcylated targets found in many cancers may also provide these cells with a selective advantage for sustained growth, enhanced metastatic potential, and immune evasion in the tumor microenvironment.

Cross-Dysregulation of O-GlcNAcylation and PI3K/AKT/mTOR Axis in Human Chronic Diseases

The hexosamine biosynthetic pathway (HBP) and the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway are considered as nutrient sensors that regulate several essential biological processes. The hexosamine biosynthetic pathway produces uridine diphosphate N-acetylglucosamine (UDP-GlcNAc), the substrate for O-GlcNAc transferase (OGT), the enzyme that O-GlcNAcylates proteins on serine (Ser) and threonine (Thr) residues. O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) and phosphorylation are highly dynamic post-translational modifications occurring at the same or adjacent sites that regulate folding, stability, subcellular localization, partner interaction, or activity of target proteins. Here we review recent evidence of a cross-regulation of PI3K/AKT/mTOR signaling pathway and protein O-GlcNAcylation. Furthermore, we discuss their co-dysregulation in pathological conditions, e.g., cancer, type-2 diabetes (T2D), and cardiovascular, and neurodegenerative diseases.