NF-κB induces abnormal centrosome amplification by upregulation of CDK2 in laryngeal squamous cell cancer.

Centrosome amplification can drive chromosomal instability (CIN) which is a major source of tumor initiation. The present study aimed to investigate the impact of nuclear factor kappa B (NF-κB) on centrosome amplification of Hep-2 cells. Immunofluorescence was performed to display centrosomes. BAY11-7082 was used as an inhibitor of NF-κB to assess the inhibition of centrosome amplification, and cyclin-dependent kinase 2 (CDK2), ensuring cell cycle cycle coordination with centrosome cycle was detected by Western blotting. Furthermore, a 1556-bp fragment of the CDK2 promoter was analyzed using the TRANSFAC-TESS software. Luciferase assay, including a series of truncated CDK2 promoters and site mutations, was carried out to determine NF-κB binding sites in the CDK2 promoter. Electrophoresis mobility shift and chromatin immunoprecipitation assays were applied to confirm whether NF-κB indeed binds to the 5'-promoter region of the CDK2 gene. To reveal the clinical significance of CDK2 expression in laryngeal squamous cell cancer, mRNA and protein levels were assessed by RT-PCR and Western blotting, respectively. We found that the transcription factor NF-κB plays a role in centrosome amplification in Hep-2 cells. Centrosome amplification is reduced by inhibition of the NF-κB pathway. Moreover, expression of the p65 subunit of NF-κB is sufficient to promote centrosome amplification and increase in CDK2 protein levels. We further identified a functional NF-κB binding site located in the CDK2 promoter. Single mutation of the NF-κB site III (construct mutIII) however resulted in 76±5% (p<0.01) luciferase activity reduction. Electromobility shift assays and chromatin immunoprecipitaton results suggest that NF-κB indeed binds to this responsive element associating with CDK2 expression and centrosome amplification. RT-PCR and Western blotting results revealed that both mRNA and protein levels of CDK2 were significantly higher in tumor tissues than those in paired adjacent normal laryngeal tissues.

[Teaching experience in integrated course of human development and genetics].

Establishment of integrated course system in human development and genetics is an important part of course reformation, and the improvement of this system is achieved by integrating the content of course, stabilizing teaching force, building teaching materials and applying problem-based learning. Integrity-PBL teaching model is founded and proved to be feasible and effective by teaching practice. Therefore, it maybe play an important role in improving teaching effect and cultivating ability of students to analyse and solve problems.

[Analysis of chromosome aberrations in the cell derived from primary cell culture of laryngeal carcinoma and the Hep-2 cell line].

OBJECTIVE: To search for characteristic chromosome changes in primary laryngeal squamous cell carcinoma (LSCC) and Hep-2 cell line and to realize the relationship between the cytogenetic abnormality and the pathogenetic mechanism in LSCC. METHODS: The fresh resulted samples of LSCC were analyzed with an improved primary cell culture for chromosome preparation and G-banding technique. Hep-2 cell line was analyzed by high resolution banding technique. Molecular cytogenetics analysis was made by chromosome 6 painting probe. RESULTS: Four primary LSCC succeeded in primary cell culture and obtained metaphases, one was tetraploid, the other three were triploid. The chromosome mode of Hep-2 cell line was from 68 to 75 and fifteen marker chromosomes were found. The most structural abnormalities of chromosome in primary LSCC and HEP-2 cell line were unbalance translocation, terminal deletion and isochromosome. The complicate aberration in chromosome 6 was common in LSCC and Hep-2. CONCLUSION: 6q-, I(5p), 17p-, 5q- are considered as characteristic chomosome changs in LSCC. Fluorescence in situ hybridization (FISH) may enhance the ability of detecting complicated chromosome rearrangements and marker chromosomes, which could provide more value data to verify the chromosome characteristic aberration in LSCC.

[The investigation of STK15 gene amplification and overexpression in laryngeal squamous cell carcinoma].

OBJECTIVE: To investigate the role of STK15 gene amplification and overexpression to genesis and development of laryngeal squamous cell carcinoma (LSCC). METHODS: STK15 gene amplification in 40 cases carcinoma tissues and normal tissues as control was detected by differential PCR approach. STK15 mRNA and protein levels were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry method. RESULTS: In 40 LSCC cases, STK15 gene amplification was found in 14 tumor tissues(35%), mRNA overexpression in 27 tumor tissues(67.5%), and protein upregulated in 29 tumor tissues(72.5%). Statistics analysis showed that STK15 gene amplification and mRNA overexpression were obviously associated to differentiation degree of LSCC, and protein overexpression was closely associated with both differentiation degree and pathological grades of LSCC. CONCLUSION: This research results suggest that STK15 gene amplification contributes to its mRNA and protein overexpression through affecting the exact replication of centrosome and separation of chromosomes. STK15 gene thus plays a role in LSCC oncogenesis and malignant progression.

[Mutation of p53 and overexpression of STK15 in laryngeal squamous-cell carcinoma].

OBJECTIVE: To explore the relationship between p53 gene mutations and STK15 abnormal expression in the development of human laryngeal squamous-cell carcinoma (LSCC). METHODS: LSCC tissues and matched normal tissues were taken during operation from 55 patients without previous chemotherapy or radiotherapy. Following polymerase chain reaction amplification direct sequencing single strand conformational polymorphism (PCR-SSCP) combined with silver staining were used to detect mutations of p53 gene in exons 7 and 8 (p53E7 and p53E8) using genomic DNA from 110 specimens including 55 LSCC tissues and 55 matched normal tissues. STK15 expression were evaluated by RT-PCR with beta-actin as internal control. RESULTS: The mutation rate of p53E7 was 30.9% (compared to normal tissues, chi(2) = 8.66, P < 0.01). There was no mutation in p53E8. In 38 of the 55 cases (69.1%), the STK15 mRNA expression level was higher than that of the paired normal tissue. The STK15 to beta-actin ratio of average density value was 1.22 +/- 0.49 in the cancer tissue, and 0.99 +/- 0.54 in the normal tissues (t = 4.539, P < 0.01). In 14 of the 17 cases (82.4%) with p53E7 mutations, the STK15 expression was higher than that of normal tissue. In the 38 cases with STK15 over-expression, p53E7 mutation was found in 14 cases (36.8%). The rate of concurrence of p53E gene mutations and STK15 over-expression (25.5%) was higher than that of only p53E gene mutations (chi(2) = 26.025, P < 0.01). CONCLUSION: There is significant association between p53 gene mutation and STK15 over-expression in laryngeal squamous-cell carcinoma.

[Deletion of p15 and pl6 genes and overexpression of STK15 gene in primary hepatocellular carcinoma].

OBJECTIVE: To investigate the association of p15 and pl6 genes deletion and STKI5 gene overexpression in primary hepatocellular carcinoma (PHC). METHODS: The carcinoma tissue and the adjacent normal tissue were taken from 30 PHC patients during operations who had had neither chemotherapy nor radiotherapy preoperatively. DNA was extracted from the tissues and PCR was used to determine the homozygous deletion of p15 exon2 (pl5E2) and pl6 exon 2 (pl6E2). RNA was extracted, cDNA was synthesized by RT-PCR, and the expression of STKI5 gene was tested by PCR. Beta-actin was used as an internal control. Average density value (ADV) of STK15 gene and that of beta-actin gene were determined in both carcinoma tissue and the adjacent normal tissue. RESULTS: The rate of p15E2 deletion was 13.3% (4/30) and the rate of p16E2 deletion was 16.7% (5/30) in the carcinoma tissue. The p15E2 and pl6E2 co-deletion rate was 6.7% (2/30). In 19 of the 30 cases (63.3%) the expression of STK15 gene in carcinoma tissue was higher than that in the adjacent normal tissue. The ratio of ADV of STK15 gene to ADV of beta-actin gene (1.53+/-0.31) in the carcinoma tissue was significantly higher than that (0.91+/-0.25) in the paired adjacent normal tissue (t = 2.86). CONCLUSION: The homozygous deletion of p15E2 and p16E2 and overexpression of STKI5 gene may play a role in the oncogenesis and malignant progression of PHC.

[Association of homozygous deletion of p15 and p16 gene and amplification of EGFR gene in laryngeal squamous cell carcinoma].

To assess the relationship of deletion of p15 and p16 gene and EGFR gene amplification in laryngeal squamous cell carcinoma (LSCC). DNA was extracted from fresh tumor. Deletion of p15 exon 2(p15E2) and p16 exon 2(p16E2) in 30 cases of LSCC was detected by polymerase chain reaction (PCR) technique. Amplification of EGFR gene in 30 cases of LSCC was detected by FISH. The rate of p15E2 deletion in 30 cases was 13.3(4/30), and that of p16E2 was 16.7% (5/30). p15E2 and p16E2 codeletion rate was 6.7% (2/30). The rate of EGFR gene amplification in 30 cases was 30% (9/30), and was amplified 2 to 8 fold. Homozygous deletion of p16E2 and p15E2 and codeletion is related with amplification of EGFR gene (P = 0.000018), and may play an important role to oncogenesis and malignant progression in LSCC.

[Comparative genomic hybridization analysis of laryngeal carcinoma].

In order to find out the genes involved in the tumorigenesis of laryngeal carcinoma, we analyzed 18 laryngeal carcinoma with comparative genomic hybridization. Results show that each one has different degree of variances, included gains and losses of partial and whole chromosome. Each case has 12.9 abnormal regions averagely; losses are more than gains, equal to 7.2 and 5.7 per case respectively. Main regions are gains in chromosomes 3q (78%), 5p (61%), 11q (56%), 1q (50%), 8p (44%), 8q (39%) and 15q (39%), and losses of 3p (70%), 5q (78%), 9p (67%), 13q (50%), 1p (44%) and 14q (39%). There are many specific gains and losses in several chromosomes,especially the increase of copy number karyotype in 1p13-21(8/18), 3p21-23 (14/18), 5p21-22 (14/18), 9p12-pter (10/18) and 13q21-31 (8/18), while the decrease in 1q11-21 (11/18), 3q15-21 (12/18), 8p22-24 (6/18), 11q12-13 (8/18), 15q21-23 (7/18), 18p11 (8/18) are the characteristic varieties. These results suggest that there are oncogene, tumor suppressor gene and other associated genes involved in the tumorigenesis.

[Study on STK15 gene abnormality and centrosomal amplification in laryngeal carcinoma].

OBJECTIVE: To investigate STK15 gene abnormality and centrosomal amplification in laryngeal carcinoma. METHODS: STK15 gene mRNA expressional level was tested in 62 cases of laryngeal squamous cell carcinoma and laryngeal squamous cell carcinoma cell line Hep-2 by reverse transcription-polymerase chain reaction(RT-PCR); the mutation of STK15 gene exon 6 and exon 7 in the same tissues and cells was detected by PCR-single strand conformation polymorphism. Immunofluorescent antibodies were used to test centrosomal amplification in Hep-2 cell line as an example. RESULTS: STK15 gene overexpressed in 39 cases of laryngeal carcinoma (63%) and Hep-2 cell line. No mutation was found in exon 6 and exon 7 of STK15 gene in the above tissues and cells. Centrosomal amplification was apparent in Hep-2 cell line. The number of centrosome in a single cell changed from 1 to 7, and Hep-2 cells with amplified centrosomes (more than 2 in one cell) were 11%-23%. CONCLUSION: STK15 gene overexpression and centrosomal amplification were first found in human laryngeal squamous cell carcinoma, which indicated that STK15 gene overexpression leading to centrosomal amplification might occur in the early stage of human laryngeal carcinogenesis and be one of the key mechanisms for the occurrence of laryngeal carcinoma.

[Deletion of p15 and p16 genes and overexpression of STK15 gene in human laryngeal squamous cell carcinoma].

OBJECTIVE: To investigate the association of p15 and p16 genes deletion, and STK15 gene overexpression with laryngeal squamous cell carcinoma (LSCC). METHODS: The cancer tissue and surrounding normal tissue were taken during operation from 50 cases of LSCC who had undergone neither chemotherapy nor radiotherapy preoperatively. DNA was extracted and PCR was used to test the homozygous deletion of p15 exon 2 (p15E2) and p16 exon 2 (p16E2). RNA was extracted, cDNA was synthesized by reverse transcription, and the expression of STK15 gene was tested by PCR with beta-actin as inner control. At the same time the expression of STK15 in human LSCC Hep-2 cell line was tested. The ratio of ADV (average density value) of STK15 gene to the ADV of beta-actin gene was calculated. RESULTS: The rate of p15E2 deletion was 12% (6/50) and that of p16E2 was 14% (7/50). The p15E2 and p16E2 codeletion rate was 6% (3/50). In 34 of the 50 cases (68%) the expression of STK15 gene in tumor tissue was higher than that of the paired surrounding normal tissue with a significant difference. The ratio of ADV of STK15 gene to ADV of beta-actin gene was 1.03 +/- 0.30 in the cancer tissue, and 0.89 +/- 0.22 in the paired normal tissue with a significant difference (t = 4.333, P < 0.01). The expression of STK15 gene was higher than that of beta-actin in Hep-2 cell line. CONCLUSION: The homozygous deletion of p15E2 and p16E2 and overexpression of STK15 gene may play a role in the oncogenesis and malignant progression of laryngeal squamous cell carcinoma.

[Expression of STK15 gene and chromosomal instability in laryngeal carcinoma].

To assess the relationship between expression of STK15 gene and chromosomal instability in laryngeal squamous cell carcinoma, RNA was extracted from 50 cases of laryngeal squamous cell carcinoma and paired normal tissue and Hep-2 cell line. cDNA was synthesized through reverse transcription, which was amplified by PCR using beta-actin as contrast. The results of electrophoresis were analysed by software to examine the expression level of STK15 gene in laryngeal carcinoma; karyotype analysis of Hep-2 cell line as an example was performed by routine and high-resolution G-banding techniques. In the 50 cases of laryngeal carcinoma, there were 34 cases whose expression of STK15 gene in tumor was higher than paired normal tissue, occupying 68%. The difference between tumor group and contrast group was prominent by statistic analysis. The expression of STK15 gene in Hep-2 cell line was higher than that of beta-actin; Chromosomal instability in Hep-2 cell line was evident: The chromosomal number range from 43 to 84 and the chromosomal model ranged from 69 to 74. The structural abnormality was represented by 13 marker chromosomes. We discovered the overexpression of STK15 gene in laryngeal carcinoma the first time. It may caused chromosomal instability through abnormal centrosome, therefore having some effect during the occurrence and development of laryngeal carcinoma.