UBE1C is upregulated and promotes neddylation of p53 in lung cancer.

NEDDylation is a type of protein post-translational modification that has high similarity to ubiquitination. UBE1C encodes NEDDylation E1 enzyme, locates at chromatin region 3p14.1 and shows high gene dosage amplification frequency in both Asian and Caucasian lung cancer patients. However, its NEDDylation substrates and roles in tumorigenesis remain elucidated. In this study, we aim to investigate the oncogenic role of UBE1C and its involvement in how NEDDylation regulates p53 in lung cancer. We found that UBE1C mRNA overexpression and DNA amplification in most of the lung cell lines and cancer patients. Patients with UBE1C overexpression showed poor prognosis. Moreover, we demonstrated that overexpression of UBE1C and NEDD8, a NEDDylation moiety, resulted in the p53 NEDDylation with inhibition of p53 acetylation at K373 residue. Importantly, UBE1C-mediated NEDDylation downregulated the transcriptional activity of p53 by inhibiting p53 ability to target promoter regions of its downstream transcription targets, consequently inhibiting the promoter activities and the expression of mRNA and protein of the p53 downstream genes including p21 and PTEN. In addition, UBE1C and NEDD8 overexpression promoted migration, invasion, and proliferation of lung cancer cells. Our findings suggest that UBE1C acts as an oncogene with prognostic potential and highlight a potential role of UBE1C-mediated NEDDylation in downregulation of p53 transcriptional activity in lung cancer.

Paeoniflorin found in Paeonia lactiflora root extract inhibits melanogenesis by regulating melanin-related signal transduction in B16F10 cells.

BACKGROUND: Skin pigmentation is modulated by various processes, with melanogenesis playing a key role. Melanin is synthesized by the catalysis of melanogenesis-related enzymes, such as tyrosinase and tyrosine-related proteins TRP-1 and TRP-2. Paeoniflorin is the main bioactive component of Paeonia suffruticosa Andr., Paeonia lactiflora., or Paeonia veitchii Lynch and has been used for centuries for its anti-inflammatory, anti-oxidant, and anti-carcinogenic properties. AIMS & METHODS: In this study, melanin biosynthesis in mouse melanoma (B16F10) cells was induced using α-melanocyte-stimulating hormone (α-MSH), and then cells were co-treated with paeoniflorin to evaluate its potential anti-melanogenic effect. RESULTS: α-MSH stimulation increased melanin content, tyrosinase activity, and melanogenesis-related markers in a dose-dependent manner. However, treatment with paeoniflorin reversed α-MSH-induced upregulation of melanin content and tyrosinase activity. Furthermore, paeoniflorin inhibited cAMP response element-binding protein activation and TRP-1, TRP-2, and microphthalmia-associated transcription factor protein expression in α-MSH-stimulated B16F10 cells. CONCLUSION: Overall, these findings show the potential of paeoniflorin as a depigmenting agent for cosmetic products.

Dysregulation of SOX17/NRF2 axis confers chemoradiotherapy resistance and emerges as a novel therapeutic target in esophageal squamous cell carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is the sixth leading cause of cancer-associated death worldwide with a dismal overall 5-year survival rate of less than 20%. The standard first-line therapy for advanced ESCC is concomitant chemo-radiation therapy (CCRT); however, patients usually develop resistance, resulting in unfavorable outcomes. Therefore, it is urgent to identify the mechanisms underlying CCRT resistance and develop effective treatment strategies. METHODS: Patients' endoscopic biopsy tumor tissues obtained before CCRT treatment were used to perform RNA-seq and GSEA analysis. Immunohistochemical (IHC) staining, chromatin immunoprecipitation (ChIP), and promoter reporter analyses were conducted to investigate the relationship between SOX17 and NRF2. Xenograft mouse models were used to study the role of SOX17/NRF2 axis in tumor growth and the efficacy of carboxymethyl cellulose-coated zero-valent-iron (ZVI@CMC). RESULTS: In this study, a notable gene expression signature associated with NRF2 activation was observed in the poor CCRT responders. Further, IHC staining of endoscopic biopsy of 164 ESCC patients revealed an inverse correlation between NRF2 and SOX17, a tumor-suppressive transcription factor with low expression in ESCC due to promoter hypermethylation. Using ChIP and promoter reporter analyses, we demonstrated that SOX17 was a novel upstream transcriptional suppressor of NRF2. In particular, SOX17low/NRF2high nuclear level significantly correlated with poor CCRT response and poor survival, indicating that the dysregulation of SOX17/NRF2 axis played a pivotal role in CCRT resistance and tumor progression. Notably, the in-house developed nanoparticle ZVI@CMC functioned as an inhibitor of DNA methyltransferases to restore expression of SOX17 that downregulated NRF2, thereby overcoming the resistance in ESCC. Additionally, the combination of ZVI@CMC with radiation treatment significantly augmented anticancer efficacy to inhibit tumor growth in CCRT resistant cancer. CONCLUSION: This study identifies a novel SOX17low/NRF2high signature in ESCC patients with poor prognosis, recognizes SOX17 as a transcriptional repressor of NRF2, and provides a promising strategy targeting SOX17/NRF2 axis to overcome resistance.