Y-box binding protein 1 augments sorafenib resistance via the PI3K/Akt signaling pathway in hepatocellular carcinoma.

BACKGROUND: Sorafenib is the first-line treatment for patients with advanced hepatocellular carcinoma (HCC). Y-box binding protein 1 (YB-1) is closely correlated with tumors and drug resistance. However, the relationship between YB-1 and sorafenib resistance and the underlying mechanism in HCC remain unknown. AIM: To explore the role and related mechanisms of YB-1 in mediating sorafenib resistance in HCC. METHODS: The protein expression levels of YB-1 were assessed in human HCC tissues and adjacent nontumor tissues. Next, we constructed YB-1 overexpression and knockdown hepatocarcinoma cell lines with lentiviruses and stimulated these cell lines with different concentrations of sorafenib. Then, we detected the proliferation and apoptosis in these cells by terminal deoxynucleotidyl transferase dUTP nick end labeling, flow cytometry and Western blotting assays. We also constructed a xenograft tumor model to explore the effect of YB-1 on the efficacy of sorafenib in vivo. Moreover, we studied and verified the specific molecular mechanism of YB-1 mediating sorafenib resistance in hepatoma cells by digital gene expression sequencing (DGE-seq). RESULTS: YB-1 protein levels were found to be higher in HCC tissues than in corresponding nontumor tissues. YB-1 suppressed the effect of sorafenib on cell proliferation and apoptosis. Consistently, the efficacy of sorafenib in vivo was enhanced after YB-1 was knocked down. Furthermore, KEGG pathway enrichment analysis of DGE-seq demonstrated that the phosphoinositide-3-kinase (PI3K)/protein kinase B (Akt) signaling pathway was essential for the sorafenib resistance induced by YB-1. Subsequently, YB-1 interacted with two key proteins of the PI3K/Akt signaling pathway (Akt1 and PIK3R1) as shown by searching the BioGRID and HitPredict websites. Finally, YB-1 suppressed the inactivation of the PI3K/Akt signaling pathway induced by sorafenib, and the blockade of the PI3K/Akt signaling pathway by LY294002 mitigated YB-1-induced sorafenib resistance. CONCLUSION: Overall, we concluded that YB-1 augments sorafenib resistance through the PI3K/Akt signaling pathway in HCC and suggest that YB-1 is a key drug resistance-related gene, which is of great significance for the application of sorafenib in advanced-stage HCC.

Pneumatosis cystoides intestinalis: six case reports and a review of the literature.

BACKGROUND: Pneumatosis cystoides intestinalis (PCI) is characterized by gas-filled cysts in the intestinal submucosa and subserosa. There are few reports of PCI occurring in duodenum and rectum. Here we demonstrated four different endoscopic manifestations of PCI and three cases with intestinal stricture all were successfully managed by medical conservative treatment. CASE PRESENTATION: There are 6 cases of PCI with varied causes encountered, in which the etiology, endoscopic features, treatment methods and prognosis of patients were studied. One case was idiopathic, while the other one case was caused by exposing to trichloroethylene (TCE), and the remaining four cases were secondary to diabetes, emphysema, therioma and diseases of immune system. Of the six patients, all complained of abdominal distention or diarrhea, three (50%) reported muco-bloody stools, two (33.3%) complained of abdominal pain. In four other patients, PCI occurred in the colon, especially the sigmoid colon, while in the other two patients, it occurred in duodenum and rectum. Endoscopic findings were divided into bubble-like pattern, grape or beaded circular forms, linear or cobblestone gas formation and irregular forms. After combination of medicine and endoscopic treatment, the symptoms of five patients were relieved, while one patient died of malignant tumors. CONCLUSION: PCI endoscopic manifestations were varied, and radiology combined with endoscopy can avoid misdiagnosis. The primary bubble-like pattern can be cured by endoscopic resection, while removal of etiology combined with drug therapy can resolve majority of secondary cases, thereby avoiding the adverse risks of surgery.

[Construction and identification of recombinant avian adeno-associated virus expressing GFP reporter gene].

To generate recombinant avian adeno-associated virus (rAAAV) for gene transfer studies in avian cells, the recombinant plasmid containing the whole genome of AAAV was digested with restriction enzymes to remove the Rep and Cap genes, resulting in AAAV transfer vector pAITR. GFP-expressing cassette was amplified by PCR and inserted into the AAAV transfer vector. The Rep-Cap gene of AAAV amplified by high fidelity PCR was subcloned into eukaryotic expression vector pcDNA3, resulting in an AAAV helper vector pcDNA-ARC. The Rep and Cap genes amplified by high fidelity PCR were subcloned separately into the co-expression vector pVITRO2-mcs, resulting in another AAAV helper vector pVITRO2-ARC. Using calcium phosphate precipitation method, rAAAV-GFP was generated by co-transfecting AAV-293 cells with a cocktail of pAITR-GFP, pcDNA-ARC or pVITRO2-ARC, and adenovirus helper vector pHelper. The three structural proteins VP1, VP2 and VP3 of correct molecular masses were detected by SDS-PAGE and the GFP reporter gene was detected by PCR in purified rAAAV-GFP virions. Chicken embryonic fibroblast (CEF) cells and CEL cell line were transduced with the recombinant virus, the GFP-positive cells were easily observed under fluorescent microscope, expression of which lasted for at least two weeks. These data demonstrate that an efficient helper virus-free packaging system has been established for generating recombinant AAAV particles for gene transfer studies in avian cells and for development of recombinant vaccines against avian diseases.