ABSTRACT
Retinoblastoma(RB)is the most common intraocular malignant tumor of children. Chemotherapy is a preferred method in RB treatment, which includes intravenous chemotherapy, intra-arterial chemotherapy and intravitreal chemotherapy. However, the occurrence of chemotherapy resistance often leads to the failure of eye-preserving treatment in RB patients. Therefore, exploring the mechanism of the occurrence of chemotherapy resistance and searching for new strategies and combined medicines for RB treatment are of great clinical significance. This article reviews that RB cells obtain chemotherapy resistance through ATP binding cassette protein(ABC transporter), non-coding RNA, epigenetics modification, autophagy, epithelial mesenchymal transformation, extracellular matrix changes and other ways, and the potential therapeutic targets for chemotherapy resistance are also summarized, in the hope of providing some references for further research on chemotherapy resistance of RB.
ABSTRACT
Objective To study the activity of the survivin gene promoter in several tumor cell lines and evaluate the possible application of this promoter in tumor gene therapy. Methods ①The expressions of survivin gene in A549,MDA-MB231 and HepG2 cell lines were detected by RT-PCR and Western blotting.②Tumor cells(A549,MDA-MB231,HepG2) were transiently transfected by reporter plasmids containing different length of survivin promoter using lipofectamine.And 48 h later,the level of reporter gene expression was analyzed.Results There were different levels of survivin expression in A549,MDA-MB231 and HepG2 cell lines.Transient transfection assay approved that pLuc-surP-987,pLuc-surP-596,pLuc-surP-269 and pLuc-surP-158 showed high activity and 269 bp survivin promoter demonstrated the highest activity. Conclusion In transcriptional level,survivin promoter can activate the reporter gene in several tumor cell lines.It is a potential candidate promoter in tumor gene therapy.
ABSTRACT
Objective To upregulate Notch signaling in cancer cells by overexpression of active part of Notch1 and to examine the proliferation of the cells. Methods Four cancer cell lines were infected with retrovirus recombined with sequence encoding active part of Notch1.CBF-1 reporter plasmid was used to detect Notch signaling and proliferation assay was carried out by MTS method.Cell cycle analysis was synchronously conducted. Results The overexpression of the active part of Notch1 induced upregulation of Notch signaling,led to growth inhibition in Hela and HepG2 cell lines and growth boost in BGC-823 cell lines,while had no effect on Chang cell lines. Conclusion The upregulation of Notch signaling can exert various effects on different cancer cell lines which is critical to the gene therapy for cancers.