ABSTRACT
Radioresistant sublines of non-small cell lung cancer cells differing in the p53 status were obtained: A549 (p53 wild type) and H1299 (p53 deficient). The exposure to ionizing radiation was carried out using a standard protocol developed on the basis of empirical clinical experience and consisting in exposure in a dose of 2 Gy once a day, 5 days a week up to total dose of 60 Gy. The cells survived after irradiation demonstrated reduced radiosensitivity, as well as changes in differential gene expression in comparison with parental cells. Some differences in the signaling pathways involved in DNA repair were revealed.
Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Carcinoma, Non-Small-Cell Lung/genetics , Carcinoma, Non-Small-Cell Lung/radiotherapy , Cell Line, Tumor , DNA Repair/genetics , Gene Expression Regulation, Neoplastic , Humans , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Lung Neoplasms/radiotherapy , Radiation Tolerance/genetics , Transcriptome , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , X-RaysABSTRACT
Hallmark of neuroblastoma is an ability of this malignant tumor to undergo spontaneous regression or differentiation into benign tumor during any stage of the disease, but it is little known about mechanisms of these phenomena. We studied effect of receptor tyrosine kinase receptor KIT on expression of genes, which may be involved in tumor spontaneous regression. Downregulation of KIT expression by RNA interference in SH-SY5Y cells causes suppression of neurotrophin receptor NGFR expression that may promote the loss of sensibility of cells to nerve growth factors, also it causes upregulation of TrkA receptor expression which can stimulate cell differentiation or apoptosis in NGF dependent manner. Furthermore there is an upregulation of genes which stimulate malignant cell detection by immune system, such as genes of major histocompatibility complex HLA class I HLA-B and HLA-C, and interferon-γ receptors IFNGR1 and IFNGR2 genes. Thus KIT can mediate neuroblastoma cell sensibility to neurotrophins and immune system components--two factors directly contributing to spontaneous regression of neuroblastoma.
Subject(s)
Gene Expression Regulation, Neoplastic , Neoplasm Regression, Spontaneous/genetics , Neuroblastoma/metabolism , Proto-Oncogene Proteins c-kit/metabolism , Apoptosis , Cell Line, Tumor , HLA Antigens/genetics , HLA Antigens/metabolism , Humans , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Neuroblastoma/genetics , Neuroblastoma/pathology , Proto-Oncogene Proteins c-kit/genetics , Receptor, trkA/genetics , Receptor, trkA/metabolism , Receptors, Interferon/genetics , Receptors, Interferon/metabolism , Receptors, Nerve Growth Factor/genetics , Receptors, Nerve Growth Factor/metabolism , Interferon gamma ReceptorABSTRACT
Gene c11orf72 (also known as FLJ90834) included in human gene reference list was previously predicted on the basis oftranscriptome analysis. We show that c11orf72 predicted protein coding open reading frame is specific for human genome and that it is absent from DNAs of other investigated primate species (chimpanzee, macaque). For the first time, we systematically analyzed c11orf72 expression in five normal and two cancerous human tissues (testicles, heart, brain, lung, bladder, bladder tumor and testicular tumor) and found no transcriptional activity there. Promoter of c11orf72, located close to promoter of a housekeeping gene NDUFV1, has shown high methylation level, whereas NDUFV1 promoter was almost free from methylation. The protein product for cllorf72 was analyzed using heterologous expression in human cell lines NT2/D1 (Tera2) and HepG2, in N- and C-terminal fusion constructs with the fluorescent protein TurboGFP. C11orf72 protein showed no cytotoxic or promitotic activity and was distributed diffusely through the cell. Our data confirm the possibility of gain of new protein-coding genes during human evolution due to simple accumulation of point mutations. However, we found no evidence for the functional significance of gene c11orf72.
