OBJECTIVEIdentification of Rb1 mutations permits accurate genetic counseling. Characterization of the causative mutation in a large low penetrance family is likely to provide important information for tumorigenesis of retinoblastoma(RB).

METHODSQuantitative fluorescent multiplex PCR QFM-PCR technique was used for mutation detection. Long fragment PCR, reverse transcriptase-PCR, subcloning, direct sequencing and Western blotting techniques were used for characterizing the mutation.

RESULTSA deletion covering exons 24 and 25 of Rb gene was found in a large family with 122 members in four generations. Of the 18 carries in the family, only 11 were delivered to either unilateral or bilateral RB. The family has much low-penetrance retinoblastoma, compared with the usual, high-penetrance RB (95%). An extent of 4 kb fragment deletion was detected in genomic deletion of the mutation. cDNA and sequence data showed a 174 bp shorter than the wild type message RNA resulting in an in-frame loss of 58 residues. Further analysis demonstrated the truncated protein expression of 6000 Da shorter than wild type RB1 protein.

CONCLUSIONQFM-PCR technique has enabled the investigators to identify a large deletion covering entire exons 24 and 25 of the Rb1 gene. It is the largest deletion ever found in low penetrance RB families. The characterizations of the mutation in genomic DNA, RNA and protein have provided new evidences which enhance credence to the idea that low penetrance retinoblastoma is caused by only partially functional disable of Rb1. The data will be useful in genetic counseling, particularly significant for the unaffected carriers in RB low penetrance families.

Exons ; Female ; Gene Deletion ; Gene Expression ; Humans ; Male ; Pedigree ; Penetrance ; Retinal Neoplasms ; genetics ; Retinoblastoma ; genetics ; Retinoblastoma Protein ; genetics

OBJECTIVETo study the characteristics of RB1 gene mutations in Chinese patients with retinoblastoma.

METHODSPeripheral blood samples of 35 patients with retinoblastoma were collected and genomic DNA was extracted. Multiplex PCR sequencing was carried out to identify RB1 gene mutations. Parents of 6 probands with RB1 mutations were also enrolled to identify the origins of mutations.

RESULTSFourteen patients were found to have carried germline mutations, among whom 11 had bilateral tumors and 3 had unilateral tumors. Sixteen germline mutations were identified, among which 13 were pathological, which included 5 nonsense mutations (c.1072C > T, c.1333C > T, c.1363C > T, c.1399C > T, c.2501C > A), 4 missense mutations (c.920C > T, c.1346G > A, c.1468G > A, c.1861C > A), 2 frameshift mutations (c.1947delG, c.2403delA) and 2 large fragment deletions (c.139_168 del30, exon 8 deletion). Three were non-pathological mutations, including 2 intronic mutations (c.540-23 dupT, c.2664-10T > A) and 1 silent mutation (c.2192T > A). One carrier was identified among the 6 parents of children carrying a RB1 mutation.

CONCLUSIONScreening for RB1 gene mutations in patients with bilateral or unilateral retinoblastoma can help to identify heritable mutations and provide important clues for genetic counseling and clinical management.

Adult ; Asian Continental Ancestry Group ; genetics ; Child ; Child, Preschool ; China ; Female ; Humans ; Infant ; Male ; Mutation ; Pedigree ; Retinoblastoma ; genetics ; Retinoblastoma Protein ; genetics ; Young Adult

OBJECTIVETo screen and clone the novel genes related to cellular proliferation of oral squamous cell carcinoma.

METHODSWe selected the Rb gene as the bait protein gene to construct the fusion bait plasmid of yeast two-hybrid. The whole code sequence of Rb gene was acquired by digestion with restricted enzyme EcoRI and BamH1 and reclaimed from its original vector pGBT9-pRb. After being confirmed by electrophoresis, the Rb gene was cloned into the MCS of the plasmid pGBKT7 to construct a recombined plasmid pGBKT7-pRb and the sequence of the recombined plasmid was detected in company. According to the protocol of yeast two hybrid system III, the competent Y187 yeast was prepared, and transformed with recombined plasmid pGBKT7-pRb. Following that, the toxicity and transcriptional activation of this recombined plasmid pGBKT7-pRb in Y187 yeast were tested.

RESULTSThe sequence of the recombined plasmid was correct compared with the sequence provided in Genbank. The protein could be correctly synthesized in vitro, and no self-activating transcriptional activation and toxicity was observed in Y187 yeast.

CONCLUSIONSThe construction of the recombined plasmid was capable to be used as the fusion bait plasmid in yeast two-hybrid system III, and the recombined Rb-protein could be used as the bait protein successfully.

Carcinoma, Squamous Cell ; genetics ; Genes, Retinoblastoma ; genetics ; Genetic Vectors ; Humans ; Mouth Neoplasms ; genetics ; Plasmids ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; Recombination, Genetic ; Retinoblastoma Protein ; biosynthesis ; genetics ; Two-Hybrid System Techniques ; Yeasts ; genetics

The research was aimed to detect the expression levels of retinoblastoma protein (pRb) in child acute leukemia cells, and to explore its possible association with leukemia cells cycle, the risk of disease, minimal residual disease (MRD) monitoring and prognosis of B-ALL. Flow cytometry (FCM) was used to detect the expression of pRb in 89 cases of acute leukemia (including 25 AML, 10 T-ALL and 54 B-ALL) and bone marrows from 7 normal children (control group). Meanwhile the cell cycle in some cases was analyzed. The results showed that (1) the FCM could accurately detect the expression of pRb in acute leukemia cells; (2) the high level of pRb expression was frequent in all types of child acute leukemias. In the same case, the expression of pRb was significantly increased in leukemia cells when compared with non-leukemia cells. And no detectable pRb protein was found in partial cases of acute leukemia; (3) there was a close relation between expression of pRb and the cell cycle of leukemia cells, the number of G(1) phase cells in pRb positive case of B-ALL was more than that in pRb negative case (92% vs 77%); (4) in B-ALL, the level of pRb expression in MRD positive group was significantly lower than that in MRD negative group (P < 0.05), but pRb expression was stable in non-leukemia cells during therapy; (5) pRb expression was related to the early response to therapy in B-ALL, the expression of pRb was significantly increased in sensitive group when compared with insensitive group (P < 0.05). It is concluded that high level or absence of pRb expression can be found in child acute leukemia cells. The expression of pRb is positively related to cell cycle of leukemia cells, MRD monitoring and the early response to therapy. In short, the detection of pRb expression level can guide the therapy and the evaluation of prognosis in B-ALL.
Burkitt Lymphoma ; metabolism ; Child ; Female ; Flow Cytometry ; Humans ; Leukemia, Myeloid, Acute ; metabolism ; Male ; Neoplasm, Residual ; Prognosis ; Retinoblastoma Protein ; biosynthesis ; genetics

OBJECTIVETo explore the mechanism of action of RbAp46 gene on leukemic cells.

METHODSK562 leukemic cells and SHG44 glioma cells were transfected with eukaryotic expression vector carrying full-length cDNA of RbAp46 driven by the cytomegalovirus promoter mediated by lipofectamine transfection reagent. Empty vector were transfected at the same time as control. G418-resistant colonies were selected after 3 weeks culturing. Series genes were amplified using RT-PCR. Growth curve and colony formation assays were performed.

RESULTSThe number of K562/RbAp46 and K562/CMV cells were (90.00 +/- 8.40) x 10(4) and (119.58 +/- 9.87) x 10(4), respectively after 4 days growth, and SHG44/RbAp46 and SHG44/CMV cells were (89.13 +/- 4.88) x 10(4) and (149.42 +/- 10.83) x 10(4), respectively after 5 days growth. Seven-day yields of K562/RbAp46 and K562/CMV cell colonies were 131.67 +/- 15.57 and 250.33 +/- 26.31, respectively (P < 0.01), while those of SHG44/RbAp46 and SHG44/CMV cells were 50.78 +/- 6.77 and 206.67 +/- 37.18, respectively (P < 0.01). The fraction of K562/RbAp46 and K562/CMV cells in S phase was (48.88 +/- 4.35)% and (62.78 +/- 4.78)% (P < 0.01), and in G(0)/G(1) phase was (29.10 +/- 4.14)% and (22.40 +/- 2.43)%, respectively (P < 0.05), and that of SHG44/RbAp46 and SHG44/CMV cells in G(0)/G(1) phase was 65.6% and 48.8%, and in S phase was 22.6% and 38.4%, respectively. Insulin-like growth factor binding protein-related protein-1 (IGFBP-rP1) gene was induced to express only in the RbAp46-over expressing K562 cells and was not in SHG44 cells.

CONCLUSIONA regulatory pathway between RbAp46 and IGFBP-rP1 genes might exit in K562 leukemic cells.

Carrier Proteins ; genetics ; Gene Expression Regulation, Neoplastic ; Genetic Vectors ; Humans ; Insulin-Like Growth Factor Binding Proteins ; genetics ; K562 Cells ; Nuclear Proteins ; genetics ; Retinoblastoma-Binding Protein 7 ; Transfection

To establish leukemic cell lines stably transfected by RbAp46 gene, electroporation was performed after optimizing the transfection condition for suspended cells. Under conditions of low voltage and high capacitance, RbAp46 was transfected into U937 by electroporation. Individual clones selected with G418 for 3 weeks were isolated. The integration and the protein levels of the exogenous RbAp46 in transfectants were determined by PCR and Western blot analysis, respectively. The subclone expressing high level of RbAp46 was then established. Viability of transfected cells was assayed by trypan blue exclusion. Cell number was counted daily to determine the growth rate. The results showed that growth rate of U937 cell lines expressing exogenous RbAp46 was about 50% lower than that in control. It is concluded that leukemic cell lines stably expressing exogenous RbAp46 were established and overexpression of RbAp46 inhibits the growth of U937 leukemic cells.
Blotting, Western ; Carrier Proteins ; genetics ; Cell Proliferation ; Electroporation ; Humans ; Nuclear Proteins ; genetics ; Retinoblastoma-Binding Protein 7 ; Transfection ; U937 Cells ; WT1 Proteins ; genetics

OBJECTIVE: To screen the differential expression of oncogenes and tumors suppressed genes(OTS genes) after human brain contusion by cDNA microrarray. METHODS: The total RNAs isolated from normal and contusion human brain tissues were purified by Oligotex to obtain mRNAs. Both sources of mRNAs were reversely transcribed to cDNAs with the incorporation of fluorescent dUTP to prepare the hybridization probes. The probe from normal tissue and the contusion brain tissue were labeled with Cy3-dUTP and Cy5-dUTP respectively. The mixed probes were hybridized to the BioDoor Chip OTS-2.2S, a cDNA microarray which contains 227 oncogenes and tumors suppressed genes. After high-stringent washing, the cDNA microarray was scanned for the fluorescent signals and showed differences between two tissues. RESULTS: Among the 227 target genes, 3 genes including Human carcinoma associated HOJ-1 (HoJ-1), Human KIAAOO65 gene,Human retinoblastoma related protein (p107) gene, showed distinct deference in expression level between the human brain contusion tissue and normal tissue. CONCLUSION The 3 genes in the brain contusion was significantly the differential expression by OTS 2.2S cDNA microarray. Further analysis of these genes will be helpful to understand the molecular mechanism of brain injury and utilization in forensic medicine.
Brain Injuries/pathology* ; Gene Expression Profiling ; Genetic Markers ; Humans ; Oligonucleotide Array Sequence Analysis ; Proto-Oncogene Proteins/genetics* ; Proto-Oncogenes/genetics* ; RNA, Messenger/biosynthesis* ; Retinoblastoma-Like Protein p107/genetics*

Apoptosis ; Brain Neoplasms ; genetics ; pathology ; Cell Proliferation ; Genes, Retinoblastoma ; genetics ; Genes, erbB-1 ; genetics ; Genes, p53 ; genetics ; Glioma ; genetics ; pathology ; Humans ; Inhibitor of Growth Protein 1 ; Intracellular Signaling Peptides and Proteins ; genetics ; Mutation ; Nuclear Proteins ; genetics ; Tumor Suppressor Proteins ; genetics

Cellular senescence is a tumor-suppressive process instigated by proliferation in the absence of telomere replication, by cellular stresses such as oncogene activation, or by activation of the tumor suppressor proteins, such as Rb or p53. This process is characterized by an irreversible cell cycle exit, a unique morphology, and expression of senescence-associated-beta-galactosidase (SA-beta-gal). Despite the potential biological importance of cellular senescence, little is known of the mechanisms leading to the senescent phenotype. p41-Arc has been known to be a putative regulatory component of the mammalian Arp2/3 complex, which is required for the formation of branched networks of actin filaments at the cell cortex. In this study, we demonstrate that p41-Arc can induce senescent phenotypes when it is overexpressed in human tumor cell line, SaOs-2, which is deficient in p53 and Rb tumor suppressor genes, implying that p41 can induce senescence in a p53-independent way. p41-Arc overexpression causes a change in actin filaments, accumulating actin filaments in nuclei. Therefore, these results imply that a change in actin filament can trigger an intrinsic senescence program in the absence of p53 and Rb tumor suppressor genes.
Actin Cytoskeleton/metabolism ; Actin-Related Protein 2-3 Complex/*metabolism ; *Cell Aging ; Cell Cycle Proteins/metabolism ; Cell Line, Tumor ; Cell Nucleus/metabolism ; Fibroblasts/physiology ; Humans ; Recombinant Proteins/genetics/*metabolism ; Retinoblastoma Protein/*deficiency/genetics ; Tumor Suppressor Protein p53/*deficiency/genetics

OBJECTIVEE2F-1 and Rb are involved in cell cycle regulation. This study was to illustrate the mechanism of transformation from benign papillomatosis to ductal carcinoma in situ (DCIS) of the breast in relation to E2F-1 and Rb expression.

METHODSIn situ hybridization (ISH) was used to determinate the expression of E2F-1 and Rb mRNA of mild papillomatosis (MP, n = 40), severe papillomatosis (SP, n = 40) and DCIS (n = 40). Immunohistochemistry (IHC) was used to examine the expression of E2F-1 and Rb protein.

RESULTSThe positive rate of E2F-1 mRNA expression in MP, SP and DCIS was 17.5%, 45.0% and 80.0%, and that of E2F-1 protein expression was 20.0%, 47.5% and 77.5%, respectively. There were significant differences among the three groups (P < 0.01), and between any two groups (P < 0.01). The positive rate of Rb mRNA expression in MP, SP and DCIS was 90.0%, 50.5% and 20.0%, and that of Rb protein expression was 85.0%, 52.5% and 22.5%, respectively, with statistically significant difference similar with that of E2F-1. With the progression of papillomatosis to DCIS, the expression of E2F-1 mRNA and protein increased, while that of Rb decreased. The protein expression by IHC was positively correlated with the mRNA expression by ISH. However, that of E2F-1 was negatively correlated with Rb.

CONCLUSIONE2F-1 and Rb might provide a valuable basis for screening high risk papillomatosis and new target of gene therapy for pre-cancerous lesions of the breast.

Breast Neoplasms ; genetics ; metabolism ; Carcinoma, Intraductal, Noninfiltrating ; genetics ; metabolism ; Cell Cycle Proteins ; biosynthesis ; genetics ; DNA-Binding Proteins ; biosynthesis ; genetics ; E2F Transcription Factors ; E2F1 Transcription Factor ; Female ; Gene Expression Regulation, Neoplastic ; Genes, Retinoblastoma ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Papilloma ; genetics ; metabolism ; Precancerous Conditions ; genetics ; metabolism ; RNA, Messenger ; biosynthesis ; genetics ; Retinoblastoma Protein ; biosynthesis ; genetics ; Transcription Factors ; biosynthesis ; genetics