Saikosaponin-d inhibits proliferation by up-regulating autophagy via the CaMKKβ–AMPK–mTOR pathway in ADPKD cells

Autosomal dominant polycystic kidney disease (ADPKD) is a common heritable human disease. Recently, the role of repressed autophagy in ADPKD has drawn increasing attention. Here, we investigate the mechanism underlying the effect of Saikosaponin-d (SSd), a sarcoplasmic/endoplasmic reticulum Ca²⁺ ATPase pump (SERCA) inhibitor. We show that SSd suppresses proliferation in ADPKD cells by up-regulating autophagy. We found that treatment with SSd results in the accumulation of intracellular calcium, which in turn activates the CaMKKβ–AMPK signalling cascade, inhibits mTOR signalling and induces autophagy. Conversely, we also found that treatment with an autophagy inhibitor (3-methyladenine), AMPK inhibitor (Compound C), CaMKKβ inhibitor (STO-609) and intracellular calcium chelator (BAPTA/AM) could reduce autophagy puncta formation mediated by SSd. Our results demonstrated that SSd induces autophagy through the CaMKKβ–AMPK–mTOR signalling pathway in ADPKD cells, indicating that SSd might be a potential therapy for ADPKD and that SERCA might be a new target for ADPKD treatment.

     

Replication of Viral Deoxyribonucleic Acid and Breakdown of Cellular Deoxyribonucleic Acid in Epstein-Barr Virus Infection

Infection of Raji cells with Epstein-Barr virus (EBV) causes suppression of cellular deoxyribonucleic acid (DNA) synthesis and fragmentation of the cellular DNA. About 1,000 copies of EBV DNA of normal size (about 5 x 10(7) daltons in a single strand, as shown in an alkaline gradient) are synthesized per cell.     

Appearance of Defective Virions in Clones of Reovirus

Virus obtained from five plaques of reovirus was serially passaged in L cells. Defective virions arose in each clone by the seventh passage. Such defective virions lacked the largest of the 10 segments of the double-stranded ribonucleic acid genome.     

Host Cell Regulation of Induction of Epstein-Barr Virus

When Epstein-Barr virus (EBV) negative cells (Raji) were treated with iododeoxyuridine, only the early antigen (EA) component was induced. There was no significant increase in EBV DNA and no virus particles were observed. Somatic-cell hybrids were prepared from the fusion of Raji and D98 cells (D98/Raji). When these cells were treated with iododeoxyuridine, early antigen EBV DNA, and virus particles were synthesized. These data suggest cellular control over the expression of the EBV genome.     

Reassociation Kinetics for Epstein-Barr Virus DNA: Nonhomology to Mammalian DNA and Homology of Viral DNA in Various Diseases

The number of Epstein-Barr virus (EBV) genomes per cell in established leukocytic lines and tissue specimens has been evaluated by measuring DNA-DNA reassociation kinetics with hydroxyapatite chromatography. Under the proper conditions, this method is sufficiently sensitive to detect EBV DNA in the amount of 0.1 genome per cell. All the samples tested that have been suspected to be without EBV DNA by cRNA hybridization proved negative by this more sensitive specific analysis. These included Hela and Hep2 cells, a negative case of Burkitt's lymphoma, two negative cases of nasopharyngeal carcinoma, and two established human leukocytic lines. Homology tests conducted with single-strand-specific nuclease S1 indicated that the viral DNA from a nasopharyngeal carcinoma and infectious mononucleosis were more than 90% homologous to EBV DNA.     

DJ‐1 Alleviates Angiotensin II‐Induced Endothelial Progenitor Cell Damage by Activating the PPARγ/HO‐1 Pathway

There is evidence that angiotensin II (Ang II) may impair the functions of endothelial progenitor cells (EPCs). It was revealed that DJ‐1 could resist oxidative stress. In this study, we investigated whether DJ‐1 could protect EPCs against Ang II‐induced cell damage. The proliferation and migration of EPCs were strongly reduced in the Ang II group and were increased by overexpression of DJ‐1. Western blotting indicated that the increased expression of the senescence marker β‐galactosidase and decreased expression of adhesion molecules (ICAM‐1, VCAM‐1) induced by Ang II were reversed after Ad‐DJ‐1 transfection. The reduced angiogenic capacity of EPCs caused by Ang II was also improved after Ad‐DJ‐1 transfection. Moreover, Ang II significantly increased the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and inflammatory cytokines (TNF‐α and IL‐1β), reduced the levels of superoxide dismutase (SOD), glutathione (GSH), and these were reversed by Ad‐DJ‐1 transfection. Expression of peroxisome proliferator‐activated receptor‐γ (PPARγ) and heme oxygenase (HO‐1) was increased by DJ‐1. Therefore, HO‐1 siRNA were constructed and transfected into EPCs, and the results showed that HO‐1 siRNA transfection inhibited the effects of DJ‐1 on EPC function. Thus, our study implies that DJ‐1 may protect EPCs against Ang II‐induced dysfunction by activating the PPARγ/HO‐1. J. Cell. Biochem. 119: 392–400, 2018. © 2017 Wiley Periodicals, Inc.     

Retracted: Nimotuzuma restrains proliferation and induces apoptosis in human osteosarcoma cells by regulation of EGFR/PI3K/AKT signal pathway

Osteosarcoma (OS) is a conversant malignant bone tumor, commonly occurs in children and adolescents. Nimotuzuma is an epidermal growth factor receptor (EGRF) monoclonal antibody agent, which has been exploited in varied solid tumors. Nevertheless, the functions of Nimotuzuma in OS remain blurry. We attempted to disclose the impacts of Nimotuzuma on OS cells proliferation and apoptosis. OS MG-63 and U2OS cells were stimulated with the disparate doses of Nimotuzuma. Then, cell viability, cell cycle, and apoptosis were appraised through executing CCK-8 and flow cytometry assays. Moreover, the change of mitochondrial membrane potential (ΔΨm) was estimated via JC-1 fluorescent probe to further probe the impacts of Nimotuzuma on cell apoptosis. The proteins of cell apoptosis, cell cycle, and EGFR/PI3K/AKT were appraised via western blot. Eventually, Nimotuzuma together EGRF or PI3K inhibitor (LY294002) were utilized to dispose MG-63 to further uncover the latent mechanism. We found that Nimotuzuma remarkably repressed cell viability at a time- and dose-dependent manners in MG-63 and U2OS cells. The percentage of the S phase cells was evidently reduced by Nimotuzuma through regulating P21, Cyclin E1, and Cyclin D1. In addition, Nimotuzuma obviously evoked cell apoptosis, meanwhile elevated Bid, Bax, and cleaved-caspase-3. Further exploration showed that Nimotuzuma decreased ΔΨm in a dose-dependent manner in MG-63 and U2OS cells. Besides, we discovered the repressive functions of Nimotuzuma in OS cells proliferation and apoptosis via hindering the EGFR/PI3K/AKT pathway. These investigations testified that Nimotuzuma repressed cell growth by restraining the EGFR/PI3K/AKT pathway in OS cells, hinting the antitumor activity of Nimotuzuma in OS.