Use of microRNA Let-7 to control the replication specificity of oncolytic adenovirus in hepatocellular carcinoma cells

Highly selective therapy for hepatocellular carcinoma (HCC) remains an unmet medical need. In present study, we found that the tumor suppressor microRNA, let-7 was significantly downregulated in a proportion of primary HCC tissues (12 of 33, 36.4%) and HCC cell lines. In line with this finding, we have engineered a chimeric Ad5/11 fiber oncolytic adenovirus, SG7011(let7T), by introducing eight copies of let-7 target sites (let7T) into the 3' untranslated region of E1A, a key gene associated with adenoviral replication. The results showed that the E1A expression (both RNA and protein levels) of the SG7011(let7T) was tightly regulated according to the endogenous expression level of the let-7. As contrasted with the wild-type adenovirus and the control virus, the replication of SG7011(let7T) was distinctly inhibited in normal liver cells lines (i.e. L-02 and WRL-68) expressing high level of let-7 (>300 folds), whereas was almost not impaired in HCC cells (i.e. Hep3B and PLC/PRF/5) with low level of let-7. Consequently, the cytotoxicity of SG7011(let7T) to normal liver cells was successfully decreased while was almost not attenuated in HCC cells in vitro. The antitumor ability of SG7011(let7T)in vivo was maintained in mice with Hep3B xenograft tumor, whereas was greatly decreased against the SMMC-7721 xenograft tumor expressing a high level of let-7 similar with L-02 when compared to the wild-type adenovirus. These results suggested that SG7011(let7T) may be a promising anticancer agent or vector to mediate the expression of therapeutic gene, broadly applicable in the treatment for HCC and other cancers where the let-7 gene is downregulated.     

LncRNA TTN-AS1 drives invasion and migration of lung adenocarcinoma cells via modulation of miR-4677-3p/ZEB1 axis

Lung adenocarcinoma is the most prevalent type of lung cancer with a high incidence and mortality worldwide. Metastasis is the major cause of high death rate in lung cancer and the potential mechanism of lung adenocarcinoma metastasis remains indistinct. Emerging investigations have demonstrated that long noncoding RNA is a kind of non–protein coding RNA and plays a critical role in cancer progression and metastasis. TTN antisense RNA 1 (TTN-AS1) has been reported to promote cell growth and metastasis in cancer. However, the function of TTN-AS1 in lung adenocarcinoma is still to be illustrated. In this study, we observed that TTN-AS1 was upregulated in tissues and cells of lung adenocarcinoma and associated with poor overall survival. TTN-AS1 promoted cell proliferation, migration, invasion, and epithelial-mesenchymal transition in lung cancer. TTN-AS1 directly bound with miR-4677-3p and negatively regulated miR-4677-3p. MiR-4677-3p rescued the inhibitive impacts of TTN-AS1 knockdown on lung adenocarcinoma. Furthermore, zinc finger E-box binding homeobox 1 (ZEB1) was the target of miR-4677-3p, and TTN-AS1 modulated ZEB1 by competing for miR-4677-3p. TTN-AS1 drove the invasion and migration of lung adenocarcinoma cells by targeting the miR-4677-3p/ZEB1 axis. To sum up, our study offers insights into the mechanism of TTN-AS1 in lung adenocarcinoma metastasis and targeting the TTN-AS1/miR-4677-3p/ZEB1 axis may be the potential innovate therapeutic strategy for the patients with lung adenocarcinoma.     

Lin28 mediates paclitaxel resistance by modulating p21, Rb and Let-7a miRNA in breast cancer cells

Resistance to chemotherapy is a major obstacle for the effective treatment of cancers. Lin28 has been shown to contribute to tumor relapse after chemotherapy; however, the relationship between Lin28 and chemoresistance remained unknown. In this study, we investigated the association of Lin28 with paclitaxel resistance and identified the underlying mechanisms of action of Lin28 in human breast cancer cell lines and tumor tissues. We found that the expression level of Lin28 was closely associated with the resistance to paclitaxel treatment. The T47D cancer cell line, which highly expresses Lin28, is more resistant to paclitaxel than the MCF7, Bcap-37 or SK-BR-3 cancer cell lines, which had low-level expression of Lin28. Knocking down of Lin28 in Lin28 high expression T47D cells increased the sensitivity to paclitaxel treatment, while stable expression of Lin28 in breast cancer cells effectively attenuated the sensitivity to paclitaxel treatment, resulting in a significant increase of IC50 values of paclitaxel. Transfection with Lin28 also significantly inhibited paclitaxel-induced apoptosis. We also found that Lin28 expression was dramatically increased in tumor tissues after neoadjuvant chemotherapy or in local relapse or metastatic breast cancer tissues. Moreover, further studies showed that p21, Rb and Let-7 miRNA were the molecular targets of Lin28. Overexpression of Lin28 in breast cancer cells considerably induced p21 and Rb expression and inhibited Let-7 miRNA levels. Our results indicate that Lin28 expression might be one mechanism underlying paclitaxel resistance in breast cancer, and Lin28 could be a potential target for overcoming paclitaxel resistance in breast cancer.     

Targeting AQP4 localization as a novel therapeutic target in CNS edema

CNS edema is a pathological phenomenon after trauma, infection, tumor growth, or obstruction of blood supply, and it also can be fatal or lead to long-term disability, psychiatric disorders, substance abuse, or self-harm [1,2]. One exciting possibility would be to control excessive water accumulation in cells. However, all trials that inhibit water channel protein failed in clinic. A recent study by Kitchen et al. [3] reported that targeting the astrocytes’ surface localization of water channel protein aquaporin-4 (AQP4) significantly relieves CNS edema. Astrocytes are the most abundant cell type of the brain and generally have a greater capacity than neurons to survive stresses [4]. Astrocyte cell function is critically affected by the lack of oxygen supply (hypoxia) to the brain, which is usually associated with CNS edema [5]. Their work holds new promise for our ability to use water-transfer strategies to treat CNS edema. Cytotoxic and vasogenic edema are primary interrelated etiological factors for the progress of CNS edema [6]. Vasogenic edema also depends on the extent of cytotoxic edema and the nature/severity of the underlying cause of the cytotoxic edema. So, understanding the pathogenesis of cytotoxic edema is important for the treatment of CNS edema. Aquaporins (AQPs) are historically known to be passive transporters of water. Lines of evidence in the last decade have highlighted the diverse function of AQPs beyond water homeostasis, including regulation of renal water balance, brain-fluid homeostasis, triglyceride cycling, and skin hydration [7]. Moreover, a subgroup of AQP water channels, termed ‘aquaglyceroporins’, also facilitates transmembrane diffusion of small, polar solutes not only water but also solutes [8,9]. AQP4 is the major subtype of AQPs expressed in astrocytes throughout the nervous system and facilitates astroglial cell migration via increasing plasma membrane water permeability, which in turn upregulates the transmembrane water fluxes during astroglial cell movement and is thus considered as an interesting therapeutic target in various neurological disorders. Astrocyte swellingmay also cause cytotoxic component disruptions of the blood–brain barrier, suggesting that astrocytes seem so sensitive to cytotoxic edema. AQP4 is a recognized contributor for the formation of cytotoxic brain edema, which is mainly a phenomenon of intracellular swelling of astrocytes. Knockdown of ‘AQP4’ or removal of the perivascular AQP4 pool by α-syntrophin or α-syntrophin deletion has been convincingly proven to counteract osmotically induced acute brain edema following ischemia and other brain injuries [10–12]. A previous study revealed that the NH2-cytosolic terminus of AQP4 interacts with metabotropic glutamate receptor 5 and assembles with the catalytic subunit of Na,K-ATPase to form a complex that has the potential function for the regulation of water permeability and potassium homeostasis in the astrocytes [13] (Fig. 1). In addition, AQP4 may trigger astrocytic Ca2+ responses, which is partly dependent on autocrine purinergic signaling (P2 purinergic receptor) activation in response to hypoosmotic stress [14] (Fig. 1). Additionally, subcellular relocalization of AQP4 in primary astrocytes is induced by calmodulin (CaM), calcium, and PKA in response to hypotonicity [15]. Further study proved that hypoxia-driven astrocyte swelling induces the increased abundance of AQP4 and initiates AQP4 cell-surface relocalization in a CaM- and PKA-dependent manner [3] (Fig. 1).     

Phylogenetic and Morphological Evolution of Green Euglenophytes Based on 18S rRNA

Green euglenophytes are a group of eukaryotes with ancient origin. In order to understand the evolution of the group, it is interesting to know which characteristics are more primitive. Here, a phylogenetic tree of green euglenophytes based on the 18S rRNA gene was constructed, and ancestral states were reconstructed based on eight morphological characters. This research clarifies the phylogenetic relationships of green euglenophytes and provides a basis for the study of the origin of these plants. The phylogenetic tree, which was constructed by Bayesian inference, revealed that: Eutreptia and Eutreptiella were sister groups and that Lepocinclis, Phacus, and Discoplastis were close relatives; Euglena, Cryptoglena, Monomorphina, and Colacium were closely related in addition to Trachelomonas and Strombomonas; and Euglena was not monophyletic. An ancestral reconstruction based on morphological characters revealed seven primitive character states: ductile surface, spirally striated, slightly narrowing or sharp elongated cauda, absence of a lorica, chloroplast lamellar, shield or large discoid, pyrenoid with sheath, and with many small paramylon grains. However, the ancestral state of the length of the flagellum could not be inferred. Euglena and Euglenaria, which both possessed all of the ancestral character states, might represent the most ancient lineages of green euglenophytes.     

Correlation of N-myc downstream-regulated gene 1 subcellular localization and lymph node metastases of colorectal neoplasms

In colorectal neoplasms, N-myc downstream-regulated gene 1 (NDRG1) is a primarily cytoplasmic protein, but it is also expressed on the cell membrane and in the nucleus. NDRG1 is involved in various stages of tumor development in colorectal cancer, and it is possible that the different subcellular localizations may determine the function of NDRG1 protein. Here, we attempt to clarify the characteristics of NDRG1 protein subcellular localization during the progression of colorectal cancer. We examined NDRG1 expression in 49 colorectal cancer patients in cancerous, non-cancerous, and corresponding lymph node tissues. Cytoplasmic and membrane NDRG1 expression was higher in the lymph nodes with metastases than in those without metastases (P < 0.01). Nuclear NDRG1 expression in colorectal neoplasms was significantly higher than in the normal colorectal mucosa, and yet the normal colorectal mucosa showed no nuclear expression. Furthermore, our results showed higher cytoplasmic NDRG1 expression was better for differentiation, and higher membrane NDRG1 expression resulted in a greater possibility of lymph node metastasis. These data indicate that a certain relationship between the cytoplasmic and membrane expression of NDRG1 in lymph nodes exists with lymph node metastasis. NDRG1 expression may translocate from the membrane of the colorectal cancer cells to the nucleus, where it is involved in lymph node metastasis. Combination analysis of NDRG1 subcellular expression and clinical variables will help predict the incidence of lymph node metastasis.     

Rhodoflexus caldus gen. nov., sp. nov., a new member of the phylum Bacteroidota isolated from a hot spring sediment

A thermophilic bacterium, designated strain SYSU G04325^T, was isolated from a hot spring sediment in Yunnan, China. Polyphasic taxonomic analyses and whole-genome sequencing were used to determine the taxonomic position of the strain. Phylogenetic analysis using 16S rRNA gene sequences indicated that strain SYSU G04325^T shows high sequence similarity to Thermoflexibacter ruber NBRC 16677^T (86.2%). The strain can be differentiated from other species of the family Thermoflexibacteraceae by its distinct phenotypic and genotypic characteristics. Cells of the strain SYSU G04325^T were observed to be aerobic, Gram-stain negative and filamentous. Growth was found to occur optimally at 45 ºC and pH 7.0. In addition, the respiratory quinone was identified as menaquinone-7, while the major fatty acids (>?10%) were identified as iso-C_15:0, iso-C_17:0 and Summed Feature 9 (iso-C_17:1ω9c). The polar lipids detected included phosphatidylethanolamine, three unidentified phospholipids, one unidentified glycolipid, five unidentified aminolipids and four unidentified polar lipids. The G?+?C content of the genomic DNA was determined to be 47.6% based on the draft genome sequence. On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU G04325^T is concluded to represent a novel species of a novel genus in the family Thermoflexibacteraceae, for which the name Rhodoflexus caldus gen. nov., sp. nov. is proposed. The type strain of Rhodoflexus caldus is SYSU G04325^T (=?MCCC 1K06127^T?=?KCTC 82848^T).

     

The higher expression and distribution of 9-cis-epoxycarotenoid dioxygenase1 (AhNCED1) from Arachis hyopgaea L. contribute to tolerance to water stress in a drought-tolerant cultivar

The 9-cis-epoxycarotenoid dioxygenase (NCED) is thought to be the rate-limiting enzyme in the abscisic acid (ABA) biosynthetic pathway. In this study, transient expression of AhNCED1 and ABA distribution were detected in the vascular cambium of a drought-tolerant peanut cultivar (Yueyou 7) under a water stress treatment. It caused increases in ABA content in this region. The synthesis of ABA and AhNCED1 in the leaves of Yueyou 7 took place more quickly than in the control cultivar (Shanyou 523). Furthermore, AhNCED1 mRNA and proteins were induced in Yueyou 7 than in Shanyou 523, coinciding with greater ABA accumulation. During the seedling, blooming, and fruiting stages, AhNCED1 protein expression was higher in Yueyou 7 than in Shanyou 523, and it was induced more quickly when the plants were under water stress. These data suggest that the drought-tolerant cultivar can synthesize and distribute ABA more rapidly than does the control cultivar because of a high level of AhNCED1 expression, which then modulates physiological responses under water stress conditions.