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Lymph node metastasis is one of the most malignant clinical features in patients with esophageal squamous cell carcinoma (ESCC). Understanding the mechanism of lymph node metastasis will provide treatment strategies for patients with ESCC. Long noncoding RNAs (lncRNA) play a critical role in the development and progression of human cancers. However, the role and mechanism of lncRNAs in lymph node metastasis remain largely unknown. Here we show that VEGFC mRNA stability–associated long noncoding RNA (VESTAR) is involved in lymph node metastasis of ESCC. VESTAR was overexpressed in ESCC tissues and was predictive of poor prognosis in patients with ESCC. In ESCC, NXF1 and SRSF3 facilitated nuclear export of VESTAR to the cytoplasm, which was associated with lymph node metastasis. Depletion of VESTAR inhibited ESCC-associated lymphangiogenesis and lymphatic metastasis. Mechanistically, VESTAR directly bound and stabilized VEGFC mRNA. VESTAR also interacted with HuR, a positive regulator of VEGFC mRNA stability, and increased HuR binding to VEGFC mRNA. Our study reveals a novel lncRNA-guided mechanism of lymph node metastasis in ESCC and may provide a potential target for treatment of ESCC lymphatic metastasis. Significance: These findings illustrate the lncRNA-guided regulation of VEGFC mRNA stability via direct RNA–RNA interactions, highlighting a therapeutic target for patients with ESCC with lymphatic metastasis.

Metabolic activities are often accompanied by cell-cycle progression, yet known connections between these two processes remain limited. Here, we identified the isocitrate dehydrogenase 3β (IDH3β) as a novel substrate of anaphase-promoting complex/cyclosome (APC/C)-CDH1 and an important regulator of the cell cycle. In esophageal squamous cell carcinoma (ESCC), IDH3β was posttranslationally upregulated in late G1 phase, and overexpression of IDH3β accelerated G1–S transition, contributing to the promotion of cell proliferation in vitro and in vivo. α-Ketoglutarate (α-KG), a crucial metabolite in tricarboxylic acid (TCA) cycle, was dependent on IDH3β level and partially accounted for IDH3β-mediated cell growth. IDH3β expression increased PFKFB3 protein levels and enhanced glucose uptake, and high expression of IDH3β correlated with poor survival in patients with ESCC, suggesting a potential application of IDH3β in prognosis. Overall, our results highlight a new molecular connection between cell-cycle regulation and the TCA cycle in ESCC. Significance: These findings show that IDH3β is an APC/C-CDH1 substrate and is expressed in a cell-cycle–dependent manner, highlighting novel molecular cross-talk between the TCA cycle and cell cycle in cancer cells.

Small cell lung cancer (SCLC) is one of the most aggressive types of cancer, yet the pathologic mechanisms underlying its devastating clinical outcome remain elusive. In this report, we surveyed 924 miRNA (miR) for their expressions in the formalin-fixed paraffin-embedded specimens from 42 patients with SCLC, and found that the downregulated miR-886-3p is closely correlated with the shorter survival of SCLC. This correlation was validated with another 40 cases. It was further discovered that loss of miR-886-3p expression was mediated by DNA hypermethylation of its promoter in both cultured SCLC cells and tumor samples. Moreover, miR-886-3p potently repressed cell proliferation, migration, and invasion of NCI-H446 cell in cell culture via suppression of the expression of its target genes: PLK1 and TGF-β1 at posttranscription levels. Forced upregulation of miR-886-3p greatly inhibited in vivo tumor growth, bone/muscle invasion, and lung metastasis of NCI-H446 cells. This newly identified miR-886-3p-PLK1/TGF-β1 nexus that modulates SCLC aggression suggests that both loss of miR-886-3p expression and hypermethylation of the miR-886 promoter are the promising indicators for poor outcome of as well as new therapeutic targets for SCLC. Cancer Res; 73(11); 3326–35. ©2013 AACR.