SERPINE2 promotes liver cancer metastasis by inhibiting c-Cbl-mediated EGFR ubiquitination and degradation.

BACKGROUND: Liver cancer is a malignancy with high morbidity and mortality rates. Serpin family E member 2 (SERPINE2) has been reported to play a key role in the metastasis of many tumors. In this study, we aimed to investigate the potential mechanism of SERPINE2 in liver cancer metastasis. METHODS: The Cancer Genome Atlas database (TCGA), including DNA methylation and transcriptome sequencing data, was utilized to identify the crucial oncogene associated with DNA methylation and cancer progression in liver cancer. Data from the TCGA and RNA sequencing for 94 pairs of liver cancer tissues were used to explore the correlation between SERPINE2 expression and clinical parameters of patients. DNA methylation sequencing was used to detect the DNA methylation levels in liver cancer tissues and cells. RNA sequencing, cytokine assays, immunoprecipitation (IP) and mass spectrometry (MS) assays, protein stability assays, and ubiquitination assays were performed to explore the regulatory mechanism of SERPINE2 in liver cancer metastasis. Patient-derived xenografts and tumor organoid models were established to determine the role of SERPINE2 in the treatment of liver cancer using sorafenib. RESULTS: Based on the public database screening, SERPINE2 was identified as a tumor promoter regulated by DNA methylation. SERPINE2 expression was significantly higher in liver cancer tissues and was associated with the dismal prognosis in patients with liver cancer. SERPINE2 promoted liver cancer metastasis by enhancing cell pseudopodia formation, cell adhesion, cancer-associated fibroblast activation, extracellular matrix remodeling, and angiogenesis. IP/MS assays confirmed that SERPINE2 activated epidermal growth factor receptor (EGFR) and its downstream signaling pathways by interacting with EGFR. Mechanistically, SERPINE2 inhibited EGFR ubiquitination and maintained its protein stability by competing with the E3 ubiquitin ligase, c-Cbl. Additionally, EGFR was activated in liver cancer cells after sorafenib treatment, and SERPINE2 knockdown-induced EGFR downregulation significantly enhanced the therapeutic efficacy of sorafenib against liver cancer. Furthermore, we found that SERPINE2 knockdown also had a sensitizing effect on lenvatinib treatment. CONCLUSIONS: SERPINE2 promoted liver cancer metastasis by preventing EGFR degradation via c-Cbl-mediated ubiquitination, suggesting that inhibition of the SERPINE2-EGFR axis may be a potential target for liver cancer treatment.

Biochemical profiling of the follicular environment to predict oocyte competence in cattle.

To identify markers of oocyte competence, we compared the biochemical characteristics of fluid and cells from follicles containing oocytes with different capacities to form an embryo. Follicles (5-6 mm) were dissected, and follicular fluid (FF), granulosa cells (GC), cumulus cells (CC) from immature and mature cumulus-oocyte-complexes (COC) were individually collected. The oocytes were matured, fertilized, and cultured individually until day 8 (D8) of development. On D8, the samples were grouped according to embryo production into those that gave rise to blastocysts (EMB) and those that did not reach the blastocyst stage (NEMB). In CCs from immature and mature COCs and GCs, expression of CASP3, SERPINE2, VCAN, LUM, FSHR, EGFR, PGR, and GHR genes was quantified. Cell-free DNA (cfDNA), progesterone, and estradiol concentrations in the FF were determined. Data were analyzed by Mann-Whitney U test (GraphPad Prism 9). GHR was highly expressed in immature CCs from the EMB group, whereas CASP3 was highly expressed in mature CCs from the NEMB group (P<0.05). During maturation, the expression of CASP3 and GHR genes increased only in the NEMB group. ART2 cfDNA was highly detected in FF of the NEMB compared to the EMB group. Progesterone concentration was similar between the groups, whereas estradiol concentration was higher (P<0.05) in the EMB than in the NEMB group. It was concluded that a higher level of GHR transcripts in immature CCs, lower CASP3 expression in CCs from matured COCs, lower levels of ART2, and higher estradiol concentrations in FF may indicate oocytes with greater potential for development.

Inhibition of the serine protease HtrA1 by SerpinE2 suggests an extracellular proteolytic pathway in the control of neural crest migration.

We previously showed that SerpinE2 and the serine protease HtrA1 modulate fibroblast growth factor (FGF) signaling in germ layer specification and head-to-tail development of Xenopus embryos. Here, we present an extracellular proteolytic mechanism involving this serpin-protease system in the developing neural crest (NC). Knockdown of SerpinE2 by injected antisense morpholino oligonucleotides did not affect the specification of NC progenitors but instead inhibited the migration of NC cells, causing defects in dorsal fin, melanocyte, and craniofacial cartilage formation. Similarly, overexpression of the HtrA1 protease impaired NC cell migration and the formation of NC-derived structures. The phenotype of SerpinE2 knockdown was overcome by concomitant downregulation of HtrA1, indicating that SerpinE2 stimulates NC migration by inhibiting endogenous HtrA1 activity. SerpinE2 binds to HtrA1, and the HtrA1 protease triggers degradation of the cell surface proteoglycan Syndecan-4 (Sdc4). Microinjection of Sdc4 mRNA partially rescued NC migration defects induced by both HtrA1 upregulation and SerpinE2 downregulation. These epistatic experiments suggest a proteolytic pathway by a double inhibition mechanism.SerpinE2 ┤HtrA1 protease ┤Syndecan-4 → NC cell migration.

Restoring BARX2 in OSCC reverses partial EMT and suppresses metastasis through miR-186-5p/miR-378a-3p-dependent SERPINE2 inhibition.

Tumor cells undergoing partial epithelial-mesenchymal transition (pEMT) are pivotal in local invasion and lymphatic metastasis of oral squamous cell carcinoma (OSCC), yet the mechanisms behind pEMT reversal remain poorly understood. In this study, the loss of BARX2 expression was revealed during the process of oral epithelial carcinogenesis and identified to activate the pEMT program, facilitate metastasis, and be associated with poor prognosis. Restoring BARX2 expression in OSCC cell lines effectively reversed tumor pEMT, evident in E/N-Cadherin switching, reduced cell invasion, proliferation, and stemness, and inhibited murine lung metastasis. BARX2 re-expression negatively correlated with several pEMT markers, notably SERPINE2, which was enriched in the invasive OSCC front, enhancing stemness and promoting metastasis, particularly in cervical lymph nodes. Furthermore, rescuing SERPINE2 impaired the inhibitory effect of BARX2 on the pEMT programs and reconstructed ECM through re-expression of MMP1. Mechanistically, we identified that BARX2 inhibited SERPINE2 through activating miR-186-5p and miR-378a-3p. These miRNAs, upregulated by BARX2, post-transcriptionally degraded SERPINE2 mRNA via targeting specific sequences. Blocking miR-186-5p and miR-378a-3p effectively abolished the negative regulatory effect of BARX2 on SERPINE2. Overall, our findings highlight BARX2 as a partial EMT-reverser in OSCC, providing fresh therapeutic prospects for restoring BARX2 signaling to inhibit invasion and metastasis.