ABSTRACT
MiRNAs can function as oncogenes or tumor suppressor genes. The abnormal expression of miRNAs leads to tumor malignant phenotypes, such as cell proliferation, apoptosis, invasion and metastasis, through which it is involved in the process of tumor initiation, progression and transcriptional regulation network. Therefore, it is important to clarify the mechanism of miRNA involved in the process of tumor initiation and progression. MiRNA regulation mechanism in tumor initiation and progression includes one-to-many and many-to-one regulation between TF-to-miRNA and miRNA-to-target gene, which increases the complexity of miRNA regulation, thus affecting the biological behavior of the tumor, The expression and activity of Drosha and Dicer in the process of miRNA affect the synthesis of mature miRNA and involve in the process of tumor initiation and progression;ceRNA may bind with miRNA by competing with miRNA targeting genes and affect biological function of miRNA as miRNA inhibitor. Therefore the abnormal expression and structure of ceRNA is an important molecular mechanism of tumor initiation and progression. This complicated regulation network comprised by multi-dimensional regulation model and specific regulation of tumor initiation and progression provides impetus to exploring the functional restoration of miRNA as a novel target for cancer diagnosis and therapy.
ABSTRACT
OBJECTIVE@#To localize and define the region of nucleus export signal (NES) on BRD7, and determine the role of this region in nucleus export of the external protein.@*METHODS@#Based on an in vitro expressed model of green fluorescence protein (GFP), we performed DNA walking analysis to set BRD7 into several sections according to the structural characteristics of BRD7, investigated the effect of different sections of BRD7 on nucleus export of GFP, defined the region of nucleus export signal sequence of BRD7, and further ascertained the content of amino acids in BRD7 and potential localization of BRD7 NES by bioinformatics.@*RESULTS@#B7C1 fragments ranged from aa219 to aa450 in BRD7 were found to target the external protein GFP into the cytoplasm detected by GFP direct fluorescence, which could be inhibited by NES inhibitor Leptomycin B (LMB). This region was rich in hydrophobic amino acid residues but no typical NES with characteristics of leucine-rich sequence by bioinformatics.@*CONCLUSION@#The region from aa219 to aa450 is primarily defined as an atypical NES in BRD7.
Subject(s)
Animals , Humans , Base Sequence , COS Cells , Cell Nucleus , Metabolism , Chlorocebus aethiops , Chromosomal Proteins, Non-Histone , Genetics , Metabolism , Cytoplasm , Metabolism , Escherichia coli , Genetics , Metabolism , Green Fluorescent Proteins , Genetics , Molecular Sequence Data , Nuclear Export Signals , Recombinant Proteins , Genetics , MetabolismABSTRACT
Objective To compare the dosimetry difference among three-dimensional conformal radiotherapy (3 DCRT),simplified intensity-modulated radiotherapy (sIMRT) and intensity-modulated radiotherapy (IMRT) in whole pelvic irradiation in postoperative rectal carcinoma,in order to optimize the protocol for clinical practice.Methods From 2006 to 2008,10 patients with stage II and ID rectal cancer after radical resection (Dixon surgery) participated in this study.3DCRT,sIMRT and IMRT were performed for each patient.The dose distribution of target volume and normal tissues,conformal index (CI) and HI were analyzed using the dose-volume histogram (DVH).Results The CI for PTV of IMRT and sIMRT was superior to that of 3DCRT.3DCRT had the best HI in PTV target area dose distribution,while IMRT was similar with sIMRT,however,there were no significant difference among them.As regarded as the protection on organs at risk,for bladder,IMRT was superior to 3DCRT and slightly better than sIMRT;for small intestine,sIMRT showed better performance than 3DCRT while IMRT was better than sIMRT but with no significant difference;for colon,no dosimetry difference was found among three plans;for caput femoris,IMRT and sIMRT were better than 3DCRT.Additionally,sIMRT was similar to 3DCRT in MU of segments,but significantly lower than IMRT.The mean values of total MU for 3DCRT,sIMRT and IMRT were 569.73 ±48.69,542.97 ±69.78,and 770.25 ±73.12,respectively.Conclusions All of 3DCRT,sIMRT and IMRT could provide target area with sufficient and accurate dose,meanwhile they could also protect organs at risk well on rectal cancer after radical resection.Compared with 3DCRT plan and IMRT plan,sIMRT plan might be the optimal plan for clinical practice.