LncRNA CRNDE promotes the development of Wilms' tumor by regulating microRNA-424.

OBJECTIVE: The aim of this study was to investigate the expression characteristics of lncRNA CRNDE in Wilms' tumor and to further investigate whether it could promote the development of Wilms' tumor via regulating microRNA-424. PATIENTS AND METHODS: Real Time-quantitative Polymerase Chain Reaction (RT-qPCR) was performed to examine the expression level of CRNDE in tumor tissues and para-cancerous tissues of patients with Wilms' tumor. Meanwhile, the expression of CRNDE in Wilms' tumor cell lines was analyzed as well. CRNDE overexpression and knockdown models were constructed using lentivirus transfection in HFWT and 17-94 cell lines, respectively. Subsequently, cell counting kit-8 (CCK-8), cell colony formation, and transwell assays were performed to explore the influence of CRNDE on the biological functions of Wilms' tumor cells. Furthermore, luciferase reporter gene assay and cell reversal experiment were applied to explore the interplay between CRNDE and microRNA-424. RESULTS: RT-qPCR results revealed that the expression level of lncRNA CRNDE in tumor tissues of patients with Wilms' tumor was remarkably higher than that of adjacent normal tissues. Also, the difference was statistically significant (p<0.05). Compared with patients with low expression of CRNDE, the risk of lymph node metastasis was significantly higher in patients with high CRNDE expression (p<0.05). Similarly, compared with control group, the proliferation and metastasis abilities of cells in CRNDE knockdown group were remarkably down-regulated (p<0.05). However, opposite results were observed in CRNDE overexpression group. In addition, our results demonstrated that microRNA-424 expression was negatively correlated with CRNDE expression in Wilms' tumor tissues. Luciferase reporter gene assay indicated that CRNDE could be targeted by microRNA-424 through specific a binding site, further regulating the malignant progression of Wilms' tumor. CONCLUSIONS: CRNDE was highly expressed in Wilms' tumor tissue and cell lines. The expression of CRNDE was correlated with the incidence rate of lymph node metastasis in patients with Wilms' tumor. In addition, CRNDE might accelerate the progression of Wilms' tumor via modulating microRNA-424.

Feeding aggregation of the tick Rhipicephalus appendiculatus (Ixodidae): benefits and costs in the contest with host responses.

Gregariousness can be advantageous in interspecific competition while intraspecific competition may favour solitude. We examined feeding behaviour of the ixodid tick, Rhipicephalus appendiculatus, in the context of interspecific (tick-host) and intraspecific (tick-tick) competition. Such competition is mediated through host rejection responses to tick infestation to which ticks respond by secreting immunodulatory saliva. We observed that group feeding adults increased their blood-feeding rate, reducing the time to mating and repletion, compared with individual feeding of paired adults. The benefits of feeding aggregation indicate direct reciprocity between ticks, most likely resulting from the shared activities of their bioactive saliva. However, fast-feeding ticks appeared to impair blood-feeding success of slow-feeding females during group feeding. This may be explained by the faster feeders exacerbating host responses on detachment that are then directed against the slower feeders. As female fecundity is generally proportional to the size of the bloodmeal, there will be a selection pressure to feed gregariously. Greater understanding of the benefits and costs of feeding aggregation may help to improve tick control strategies.

Molecular individuality and adaptation of the tick Rhipicephalus appendiculatus in changed feeding environments.

The tick Rhipicephalus appendiculatus Neumann (Acari: Ixodidae) naturally infests many host species. However, the mechanisms that enable it to feed on such a wide range of hosts are unclear. One possibility is that a tick population maintains molecular (genotypic and/or phenotypic) diversity among individuals such that individuals vary in their competency in taking bloodmeals under different feeding conditions. As a first step in testing this hypothesis, we showed that the polymorphism of salivary gland proteins, previously demonstrated in unfed ticks, was maintained during feeding on guinea-pigs. We then compared feeding performance under standard laboratory rearing conditions: one instar (adults or nymphs) feeding on guinea-pigs, with three changed conditions: (1) two instars (adults and nymphs) feeding together on guinea-pigs; (2) one instar (adults or nymphs) feeding on hamsters; and (3) two instars (adults and nymphs) feeding together on hamsters. The mean engorged weight of adult females was significantly reduced under all changed conditions, indicating that most of the adult individuals were significantly challenged by the changed conditions. However, some individuals achieved successful engorgement, indicating competence to the changed condition, and demonstrating variation in adaptive ability among individuals. Engorged females produced egg masses positively correlated to the engorged weights. More interestingly, the correlation coefficient (R) increased when feeding condition was changed. This may lead to more efficient selection for population adaptation under the changed conditions. As the feeding success of ixodid ticks depends on the efficiency of the cocktail of immunomodulatory saliva, the relevance of the polymorphism of salivary gland proteins and host adaptation is discussed.