BackgroundMounting evidence has showed that Tumor-associated calcium signal transducer 2 (Trop2) is upregulated in various kinds of human cancers and plays important roles in tumorigenesis. However, the expression status and functional significance of Trop2 in thyroid cancer are largely unknown.MethodsWe first determined the expression of Trop2 by using RNAseqV2 data sets for thyroid cancer deposited on The Cancer Genome Atlas (TCGA) website. The expression of Trop2 was then confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry assays. Cell invasion and migration were assessed by conducting Transwell and wound healing assays. Furthermore, we explored the underlying mechanisms by using real-time RT-PCR, Western blot, zymography, and luciferase reporter assays.ResultsIn this study, we demonstrated that the expression of Trop2 was significantly elevated in thyroid cancer and that its expression level was correlated with the tumor-node-metastasis (TNM) staging and N classification. Dysregulation of Trop2 altered the invasive capability of thyroid cancer cells. Further mechanistic study revealed that MMP2 expression was upregulated by Trop2. Moreover, we found that the effects of Trop2 were dependent on ERK and JNK pathways. The results from clinical specimens showed that Trop2 expression correlated with MMP2 expression in primary thyroid cancer.ConclusionThe current study suggests that elevated expression of Trop2 may represent an important molecular hallmark that is biologically and clinically relevant to the progression of thyroid cancer.

Aquaporins (AQPs) play important roles in plant growth, development and tolerance to environmental stresses. To understand the role of AQPs in the mangrove plant Kandelia obovata, which has the ability to acquire water from seawater, we identified 34 AQPs in the K. obovata genome and analysed their structural features. Phylogenetic analysis revealed that KoAQPs are homologous to AQPs of Populus and Arabidopsis, which are evolutionarily conserved. The key amino acid residues were used to assess water-transport ability. Analysis of cis-acting elements in the promoters indicated that KoAQPs may be stress-and hormone-responsive. Subcellular localization of KoAQPs in yeast showed most KoAQPs function in the membrane system. That transgenic yeast with increased cell volume showed that some KoAQPs have significant water-transport activity, and the substrate sensitivity assay indicates that some KoAQPs can transport H 2 O 2 . The transcriptome data were used to analyze the expression patterns of KoAQPs in different tissues and developing fruits of K. obovata. In addition, real-time quantitative PCR analyses combined transcriptome data showed that KoAQPs have complex responses to environmental factors, including salinity, flooding and cold. Collectively, the transport of water and solutes by KoAQPs contributed to the adaptation of K. obovata to the coastal intertidal environment.

Aegiceras corniculatum is a major mangrove plant species adapted to waterlogging and saline conditions, grows in the coastal intertidal zone of tropical and subtropical regions. Here, we present a chromosome-level genome assembly of A. corniculatum by incorporating PacBio long-read sequencing and Hi-C technology. The results showed that the PacBio draft genome size is 906.63 Mb. Hi-C scaffolding anchored 885.06 Mb contigs (97.62% of draft assembly) onto 24 pseudochromosomes. The contig N50 and scaffold N50 were 7.1 Mb and 37.74 Mb, respectively. Out of 40,727 protein-coding genes predicted in the study, 89% have functional annotations in public databases.We also showed that of the 603.93 Mb repetitive sequences predicted in the assembled genome, long terminal repeat retrotransposons constitute 41.52%. The genome evolution analysis showed that the A. corniculatum genome experienced two wholegenome duplication events and shared the ancient γ whole-genome triplication event.A comparative genomic analysis revealed an incidence of expansion in 1,488 gene families associated with essential metabolism and biosynthetic pathways, including photosynthesis, oxidative phosphorylation, phenylalanine, glyoxylate, dicarboxylate metabolism, and DNA replication, which probably constitute adaptation traits that allow the A. corniculatum to survive in the intertidal zone. Also, the systematic characterization of genes associated with flavonoid biosynthesis pathway and the AcNHX gene family conducted in this study will provide insight into the adaptation mechanism of A. corniculatum to intertidal environments. The high-quality genome reported here can provide historical insights into genomic transformations that support the survival of A. corniculatum under harsh intertidal habitats.

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Hydrogen sulfide (H2S), is a crucial biological player in plants. Here, we primarily explored the interaction between sodium hydrosulfide (NaHS, a H2S donor) and the fluxes of Na+ and K+ from the salt glands of mangrove species Avicennia marina with non-invasive micro-test technology (NMT) and quantitative real-time PCR (qRT-PCR) approaches under salinity treatments. The results showed that under 400 mM NaCl treatment, the addition of 200 μM NaHS markedly increased the quantity of salt crystals in the adaxial epidermis of A. marina leaves, accompanied by an increase in the K+/Na+ ratio. Meanwhile, the endogenous content of H2S was dramatically elevated in this process. NMT result revealed that the Na+ efflux was increased from salt glands, while K+ efflux was decreased with NaHS application. On the contrary, the effects of NaHS were reversed by H2S scavenger hypotaurine (HT), and DL-propargylglycine (PAG), an inhibitor of cystathionine-γ-lyase (CES, a H2S synthase). Moreover, enzymic assay revealed that NaHS increased the activities of plasma membrane and tonoplast H+-ATPase. qRT-PCR analysis revealed that NaHS significantly increased the genes transcript levels of tonoplast Na+/H+ antiporter (NHX1), plasma membrane Na+/H+ antiporter (SOS1), plasma membrane H+-ATPase (AHA1), and tonoplast H+-ATPase subunit c (VHA-c1), while suppressed above-mentioned gene expressions by the application of HT and PAG. Overall, H2S promotes Na+ secretion from the salt glands of A. marina by up-regulating the plasma membrane and tonoplast Na+/H+ antiporter and H+-ATPase.