Epithelial cells acquire mesenchymal phenotypes through epithelial‐mesenchymal transition (EMT) during cancer progression. However, how epithelial cells retain their epithelial traits and prevent... Show moreEpithelial cells acquire mesenchymal phenotypes through epithelial‐mesenchymal transition (EMT) during cancer progression. However, how epithelial cells retain their epithelial traits and prevent malignant transformation is not well understood. Here, we report that the long noncoding RNA LITATS1 (LINC01137, ZC3H12A‐DT) is an epithelial gatekeeper in normal epithelial cells and inhibits EMT in breast and non‐small cell lung cancer cells. Transcriptome analysis identified LITATS1 as a TGF‐β target gene. LITATS1 expression is reduced in lung adenocarcinoma tissues compared with adjacent normal tissues and correlates with a favorable prognosis in breast and non‐small cell lung cancer patients. LITATS1 depletion promotes TGF‐β‐induced EMT, migration, and extravasation in cancer cells. Unbiased pathway analysis demonstrated that LITATS1 knockdown potently and selectively potentiates TGF‐β/SMAD signaling. Mechanistically, LITATS1 enhances the polyubiquitination and proteasomal degradation of TGF‐β type I receptor (TβRI). LITATS1 interacts with TβRI and the E3 ligase SMURF2, promoting the cytoplasmic retention of SMURF2. Our findings highlight a protective function of LITATS1 in epithelial integrity maintenance through the attenuation of TGF‐β/SMAD signaling and EMT. Show less
Liu, S.J.; Dinther, M. van; Hagenaars, S.C.; Gu, Y.Z.; Kuipers, T.B.; Mei, H.L.; ... ; Dijke, P. ten 2023
Triple-negative breast cancer (TNBC) is the most challenging breast cancer subtype to treat due to its aggressive characteristics and low response to the existing clinical therapies. Distant... Show moreTriple-negative breast cancer (TNBC) is the most challenging breast cancer subtype to treat due to its aggressive characteristics and low response to the existing clinical therapies. Distant metastasis is the main cause of death of TNBC patients. Better understanding of the mechanisms underlying TNBC metastasis may lead to new strategies of early diagnosis and more efficient treatment. In our study, we uncovered that the autophagy receptor optineurin (OPTN) plays an unexpected role in TNBC metastasis. Data mining of publicly available data bases revealed that the mRNA level of OPTN in TNBC patients positively correlates with relapse free and distance metastasis free survival. Importantly, in vitro and in vivo models demonstrated that OPTN suppresses TNBC metastasis. Mechanistically, OPTN inhibited the pro-oncogenic transforming growth factor-beta (TGF beta) signaling in TNBC cells by interacting with TGF beta type I receptor (T beta RI) and promoting its ubiquitination for degradation. Consistent with our experimental findings, the clinical TNBC samples displayed a negative correlation between OPTN mRNA expression and TGF beta gene response signature and expression of proto-typic TGF beta target genes. Altogether, our study demonstrates that OPTN is a negative regulator for TGF beta receptor/SMAD signaling and suppresses metastasis in TNBC. Show less
Zhang, J.; Zon, G. van der; Ma, J.; Mei, H.L.; Cabukusta, B.; Agaser, C.C.; ... ; Dijke, P. ten 2022
Epithelial-mesenchymal transition (EMT) is pivotal in the initiation and development of cancer cell metastasis. We observed that the abundance of glycosphingolipids (GSLs), especially ganglioside... Show moreEpithelial-mesenchymal transition (EMT) is pivotal in the initiation and development of cancer cell metastasis. We observed that the abundance of glycosphingolipids (GSLs), especially ganglioside subtypes, decreased significantly during TGF-beta-induced EMT in NMuMG mouse mammary epithelial cells and A549 human lung adenocarcinoma cells. Transcriptional profiling showed that TGF-beta/SMAD response genes and EMT signatures were strongly enriched in NMuMG cells, along with depletion of UDP-glucose ceramide glucosyltransferase (UGCG), the enzyme that catalyzes the initial step in GSL biosynthesis. Consistent with this finding, genetic or pharmacological inhibition of UGCG promoted TGF-beta signaling and TGF-beta-induced EMT. UGCG inhibition promoted A549 cell migration, extravasation in the zebrafish xenograft model, and metastasis in mice. Mechanistically, GSLs inhibited TGF-beta signaling by promoting lipid raft localization of the TGF-beta type I receptor (T beta RI) and by increasing T beta RI ubiquitination and degradation. Importantly, we identified ST3GAL5-synthesized a-series gangliosides as the main GSL subtype involved in inhibition of TGF-beta signaling and TGF-beta-induced EMT in A549 cells. Notably, ST3GAL5 is weakly expressed in lung cancer tissues compared to adjacent nonmalignant tissues, and its expression correlates with good prognosis. Show less
Yan, X.H.; Zhang, L.; Miyazawa, K.; Dijke, P. ten 2022
Glycosylation is a common posttranslational modification on membrane-associated and secreted proteins that is of pivotal importance for regulating cell functions. Aberrant glycosylation can lead to... Show moreGlycosylation is a common posttranslational modification on membrane-associated and secreted proteins that is of pivotal importance for regulating cell functions. Aberrant glycosylation can lead to uncontrolled cell proliferation, cell-matrix interactions, migration and differentiation, and has been shown to be involved in cancer and other diseases. The epithelial-to-mesenchymal transition is a key step in the metastatic process by which cancer cells gain the ability to invade tissues and extravasate into the bloodstream. This cellular transformation process, which is associated by morphological change, loss of epithelial traits and gain of mesenchymal markers, is triggered by the secreted cytokine transforming growth factor-beta (TGF-beta). TGF-beta bioactivity is carefully regulated, and its effects on cells are mediated by its receptors on the cell surface. In this review, we first provide a brief overview of major types of glycans, namely,N-glycans,O-glycans, glycosphingolipids and glycosaminoglycans that are involved in cancer progression. Thereafter, we summarize studies on how the glycosylation of TGF-beta signaling components regulates TGF-beta secretion, bioavailability and TGF-beta receptor function. Then, we review glycosylation changes associated with TGF-beta-induced epithelial-to-mesenchymal transition in cancer. Identifying and understanding the mechanisms by which glycosylation affects TGF-beta signaling and downstream biological responses will facilitate the identification of glycans as biomarkers and enable novel therapeutic approaches. Show less
