Clinical evidence suggests that there exists a strong correlation between Zika virus (ZIKV) infection and abnormal development of the nervous system. However, the underlying mechanisms remain to be elusive. In this study, recombinant lentiviral vectors coding for ZIKV structural proteins and truncations (prM-Env, M-Env and Env) were transduced into PC12 cells. Envelope (Env) overexpression induced significant inhibition of proliferation and triggered G2/M cell cycle arrest and apoptosis in PC12 cells. Flow cytometry and western blot analysis showed that the apoptosis was associated with up-regulation of both p53 and p21^Cip1/Waf1 and down-regulation of cyclin B1. Presence of aberrant nuclei clusters were confirmed by immunofluorescence staining analysis. The data indicate that overexpression of prM-Env, M-Env or Env led to apoptosis via an intrinsic cell death signaling pathway that is dependent on the activation of caspase-9 and caspase-3 and accompanied by an increased ratio of Bax to Bcl-2 in transduced PC12 cells. In summary, our results suggest that ZIKV Env protein causes apoptosis in PC12 cells via an intrinsic cell death signaling pathway, which may contribute to ZIKV-induced abnormal development of the nervous system.

Solute carrier family 35 member B4 (SLC35B4), a nucleotide sugar transporter, is capable of transporting UDP-xylose and UDP-GlcNAc from the cytoplasm to the lumen of the endoplasmic reticulum and Golgi. SLC35B4 has a pivotal role in glycosylation of biological macromolecules. However, its functional roles and regulatory mechanisms in malignant diseases remain unknown. Here, using the cDNA arrays, promoter reporter assays, and chromatin immunoprecipitation assays, we demonstrated that SLC35B4 is directly transactivated by YAP1–TEADs complex in gastric cancer (GC) cells. CCK-8, plate colony formation and soft agar assays revealed that SLC35B4 is essential for survival and proliferation in GC cells and nude mice models. SLC35B4 expression is markedly higher in GC tissues compared with control noncancerous tissues. Immunohistochemistry revealed that SLC35B4 expression is positively correlated with YAP1 expression in human GC tissues, and this correlation is also confirmed in the GC TCGA data set. GC patients with high levels of SLC35B4 expression have poorer prognosis than those with low levels of SLC35B4 expression. Collectively, our findings defined SLC35B4 as an important downstream oncogenic target of YAP1, suggesting that dysregulated signaling of a novel YAP1/SLC35B4 axis promotes GC development and progression, and this axis could be a potential candidate for prognosis and therapeutics in GC.

The present study aimed to determine whether actinomycin X2 (AX2) intercepted the mTOR/PTEN/PI3K/Akt signaling pathway to inhibit human prostate cancer cells (PC-3) in vitro. The effects of AX2 on mTOR, PTEN, PI3K, and Akt at the protein level and mRNA were determined by western blotting and real-time reverse transcription-PCR (RT-PCR), respectively. Concurrently, the effects of AX2 on expression levels of MiRNA144 and MiRNA126 in PC-3 were measured by real-time RT-PCR. The association of MiRNA144 with 3'-UTR of mTOR was identified using the Dual-Luciferase Reporter Gene System. The direct effect of MIRNA144 on the mTOR/PTEN/PI3K/Akt pathway was determined by real-time RT-PCR and western blotting. Apoptosis of PC-3 cells induced by AX2 was determined by MTT and flow cytometry. The results indicated that mTOR/PTEN/PI3K/Akt were decreased and PTEN was increased by AX (1, 10 µmol/l) at protein and mRNA levels in a dose-dependent manner. MiRNA144 was decreased, whereas MiRNA126 was increased by AX2. MiRNA144 associated with 3'-UTR of mTOR was corroborated. Overexpression of MiRNA144 decreased mTOR, but did not affect PTEN, PI3K, or Akt. The proliferation rates of AX2 on PC-3 cells were decreased. It suggests that AX2 induces apoptosis of PC-3 cells via meddling in the mTOR/PTEN/PI3K/Akt signaling pathway, but those effects are compounded by MiRNA144. Both AX2 and MiRNA144 intercept the signaling in different ways but cross on mTOR.