转录因子E2F1在外阴鳞癌中的表达及意义

目的:探讨转录因子E2F1在外阴鳞癌(VSCC)中的表达情况及其临床意义。方法:采用PCR（qRT-PCR）、Western blot和免疫组化检测30例VSCC及对应癌旁组织中E2F1的水平,分析E2F1表达与临床病理参数的关系。结果:VSCC组织中E2F1的mRNA相对表达量为(1.27±0.04),高于癌旁外阴组织的E2F1水平(0.84±0.06)（P＜0.05）;VSCC组织中E2F1的蛋白相对表达量为(1.16±0.04),高于癌旁外阴组织的E2F1水平(0.93±0.03)（P＜0.05）;免疫组化示VSCC组织中E2F1的阳性表达率(56.67%,17/30)明显高于癌旁外阴组织(33.33%,10/30)(P＜0.05),且其阳性表达率与FIGO分期有关(P＜0.05)。结论:E2F1在VSCC组织中表达上调,且与FIGO分期有关,提示E2F1可能与VSCC的发生、发展有关。     

4-hexylresorcinol stimulates the differentiation of SCC-9 cells through the suppression of E2F2, E2F3 and Sp3 expression and the promotion of Sp1 expression

The dormancy-inducing factors of bacteria inhibit tumor cell growth. In the present study, we evaluated the antitumor effects of the dormancy-inducing factor 4-hexylresorcinol (4-HR) using real-time cell electronic sensing (RT-CES) in SCC-9 cells (tongue squamous cell carcinoma cells). Treatment with 4-HR suppressed the growth of SCC-9 cells in a dose-dependent manner. We used a DNA microarray to identify genes that showed a significant change in expression upon 4-HR administration in SCC-9 cells. Among the differentially expressed genes, the protein expression of several cell proliferation related factors, including E2F1, E2F2, E2F3, E2F4, E2F5, E2F6, Sp1 and Sp3, were determined by western blot analyses. Treatment with 4-HR strongly suppressed E2F2 and slightly suppressed E2F3 but did not change the expression of E2F1, E2F4, E2F5 and E2F6 relative to no treatment. Furthermore, 4-HR increased Sp1 expression in a dose-dependent manner and decreased Sp3 expression. Therefore, the ratio of Sp1 to Sp3, an important driving force of epithelial cell differentiation, was drastically increased. Consistent with this observation, 4-HR increased the expression of the epithelial cell differentiation markers involucrin and keratin 10. Together, our results indicate that 4-HR induces the differentiation of SCC-9 via the modulation of the E2F-mediated signaling pathway.     

Cyclin D1 overexpression related to retinoblastoma protein expression as a prognostic marker in human oesophageal squamous cell carcinoma.

The relationship between aberrant expression of cyclin D1 and retinoblastoma (RB) protein and clinicopathological factors was investigated in 80 patients with oesophageal SCC using immunohistochemical analyses. Heterogeneous staining of cancer cell nuclei with antibody to cyclin D1 was found in 31.3% of patients (25 out of 80 patients). Nuclear staining of cancer cells with anti-RB antibody was homogeneous in 10.0% (8 out of 80 patients) and heterogeneous in 58.8% (47 out of 80 patients). Among cases with homogeneous staining for RB protein, 75% (six out of eight patients) exhibited simultaneous positivity for cyclin D1 (P < 0.05). No significant relationship was found between cyclin D1 or RB protein expression and various clinicopathological parameters. The prognosis of patients with cyclin D1-positive tumours was significantly poorer than that of the other patients (P < 0.01). In addition, when patients with cyclin D1-positive and -negative tumours were stratified according to presence or absence of lymph node metastasis and RB status, the cumulative survival rates in the cyclin D1-positive groups were significantly lower for patients without lymph node metastasis (P < 0.01) and for patients whose tumours were positive for RB (P< 0.0001). These findings suggest the possibility that cyclin D1 positivity is a useful prognostic marker related to lymph node metastasis and RB protein expression in human oesophageal SCC, in addition to clinicopathological factors.     

E2F-1 induces proliferation-specific genes and suppresses squamous differentiation-specific genes in human epidermal keratinocytes

Squamous differentiation of keratinocytes is associated with decreases in E2F-1 mRNA expression and E2F activity, and these processes are disrupted in squamous cell carcinoma cell lines. We now show that E2F-1 mRNA expression is increased in primary squamous cell carcinomas of the skin relative to normal epidermis. To explore the relationship between E2F-1 and squamous differentiation further, we examined the effect of altering E2F activity in primary human keratinocytes induced to differentiate. Promoter activity for the proliferation-associated genes, cdc2 and keratin 14, are inhibited during squamous differentiation. This inhibition can be inhibited by overexpression of E2F-1 in keratinocytes. Overexpression of E2F-1 also suppressed the expression of differentiation markers (transglutaminase type 1 and keratin 10) in differentiated keratinocytes. Blocking E2F activity by transfecting proliferating keratinocytes with dominant negative E2F-1 constructs inhibited the expression of cdc2 and E2F-1, but did not induce differentiation. Furthermore, expression of the dominant negative construct in epithelial carcinoma cell lines and normal keratinocytes decreased expression from the cdc2 promoter. These data indicate that E2F-1 promotes keratinocyte proliferation-specific marker genes and suppresses squamous differentiation-specific marker genes. Moreover, these data indicate that targeted disruption of E2F-1 activity may have therapeutic potential for the treatment of squamous carcinomas. Oncogene (2000).     

E2F3在喉鳞状细胞癌中的表达及临床意义

目的：探讨喉鳞癌中E2F3的表达与临床意义,为喉鳞癌的诊断、评估及治疗寻找辅助生物学指标。方法：采用免疫组化方法检测喉鳞癌组织及癌旁正常切缘组织中E2F3表达,结合喉鳞癌各临床参数,用SPSS16.0软件包进行统计分析E2F3表达情况与喉鳞癌各临床特征之间的关系。结果：E2F3在喉鳞癌与癌旁正常切缘中的阳性表达率分别为90.44%（123/136）和27.85%（22/79）,差异具有显著统计学意义（P〈0.001）;E2F3高表达与喉鳞癌患者年龄、临床分期及分型均相关（P〈0.05）。结论：E2F3核表达可能参与喉鳞癌发生发展过程;E2F3浆表达可能贯穿于喉鳞癌发生的整体过程。     

食管鳞癌组织中COL1A2基因的表达与临床病理特征的相关性研究

目的探讨Ⅰ型胶原α2（COL1A2）和鳞状细胞癌相关抗原(SCCAg)与临床病理特征的关系。方法TIMER 20和GEPIA数据库分析COL1A2在肿瘤及食管癌中的表达,化学发光法检测血清中SCCAg的水平,免疫组化法检测食管鳞癌组织和癌旁正常组织中COL1A2蛋白的表达。生存分析采用GEPIA数据库,基因集富集分析采用GSEA数据库。结果GEPIA数据库分析显示,食管鳞癌中COL1A2的表达高于正常组织（P<005）,食管鳞癌TNM分期及与COL1A2的表达相关（P<005）。SCCAg在食管鳞癌患者中的阳性率为486%,其在高分化食管鳞癌患中表达增高（P<005）。COL1A2蛋白在食管鳞癌中强阳性率为735%,显著高于癌旁组织56%（P<005）。COL1A2过表达与食管鳞癌分化程度及其临床分期相关（P<005）。GEPIA数据库分析显示高表达COL1A2的患者无瘤生存率显著降低（P<005）。GSEA分析表明差异基因主要集中在粘着斑通路、细胞外基质结构组分、内质网内腔、细胞外结构组织。结论血清SCCAg的高表达对食管鳞癌诊断及其分化程度预测有一定的应用价值,而食管鳞癌组织COL1A2的高表达与食管鳞癌的进展及预后不良有关,对食管鳞癌的预后的判断有一定的临床参考价值,有望成为食管鳞癌新的治疗靶点。     

Cyclin B1 overexpression and resistance to radiotherapy in head and neck squamous cell carcinoma

Radiotherapy (RT) and surgery are the cornerstones in treating head and neck squamous cell carcinoma (HNSCC). RT is effective in the initial treatment of early to intermediate stage HNSCC but less effective for locally advanced disease, some cases of which are best managed using the combination of surgery and RT. Although various clinical/pathologic parameters have been used to classify patients according to their likelihood of responding to RT, they have generally low predictive value. We have shown previously that cyclin B1 is associated with a poor clinical outcome in HNSCC patients. In this study, we investigate the potential role of cyclin B1 in assessing RT response in patients with HNSCC. Tumor specimens obtained from 80 patients participated in a prospective Phase III clinical trial addressing the dose and fractionation regimen of postoperative RT were analyzed for cyclin B1 expression by immunohistochemistry. Patients were classified according to currently accepted clinical/pathologic parameters into three risk groups, i.e., low, intermediate, and high risk, and received surgery alone, surgery plus intermediate-dose RT, and surgery plus high-dose RT, respectively. The median follow-up duration was 4.9 years. Cyclin B1 overexpression was noted in 38 of the 80 (47%) HNSCC tumors. Interestingly, 11 of the 38 patients (29%) with cyclin B1-overexpressing tumors experienced local or nodal recurrence compared with only 3 of 42 patients (7%) having carcinomas with no or weak cyclin B1 expression (P = 0.01). When locoregional control was used as the end point for the high-risk group, patients whose tumors showed cyclin B1 overexpression had a statistically significant higher tumor recurrence and metastasis compared with patients whose tumors showed no cyclin B1 overexpression (P = 0.01). Our results indicate that tumors overexpressing cyclin B1 may be resistant to RT, and cyclin B1 may be an indicator of the risk of locoregional recurrence and metastasis in patients having HNSCC receiving RT.     

喉鳞状细胞癌中PIN1基因扩增及表达异常

目的：研究PIN1基因在喉癌组织中的表达情况。方法：采用差异PCR、核型分析方法检测喉鳞癌及癌旁对照组织中PIN1基因扩增情况;采用RT-PCR检测同批组织中PIN1 mRNA表达情况;采用免疫组织化学、Western Blot方法检测PIN1蛋白表达情况。结果：与癌旁对照组织相比,40例喉癌组织中有9例（9/40,22.5%）存在PIN1基因扩增,27例（27/40,67.5%）PIN1 mRNA过表达,26例（26/40,65%）PIN1蛋白过表达（P〈0.05）。40例中17例原代培养成功,可制备中期染色体标本,其中3例（3/17,17.65%）存在19号染色体增加。结论：喉鳞状细胞中PIN1基因拷贝数增加,PIN1 mRNA和蛋白质过表达,可能与喉癌发生发展有关。     

Histone demethylase GASC1, a potential prognostic and predictive marker in esophageal squamous cell carcinoma

Gene amplified in squamous cell carcinoma 1 (GASC1) is a member of Jumonji C-domain containing histone demethylases that play an essential role in affecting chromatin architecture and gene expression. The purpose of this study was to determine the expression features and the clinical significance of GASC1 in esophageal squamous cell carcinoma (ESCC). GASC1 expression was detected on tissue microarrays of ESCC samples in 185 cases using immunohistochemical staining. Strong nuclear staining for GASC1 was observed in a subset of ESCC samples. The nuclear expression of GASC1 was significantly associated with lymph node metastasis (P=0.030) and tumor-node metastasis stages (P=0.013). Kaplan-Meier survival analysis showed a tendency that high expression of GASC1 in the nucleus was associated with poor survival of ESCC patients, with a 5-year survival rate of 26.5%, as compared to 43.7% for patients with GASC1-negative/low expression. Furthermore, multivariate analysis revealed that high expression of GASC1 likely acts as a predictive factor for overall survival of ESCC patients, despite the P-value failing to reach significance (P=0.059). The findings indicate that histone demethylase GASC1 may play an important role in promoting cancer metastasis, and shed new light on the importance of targeting GASC1 to suppress metastatic disease in various tumor types, including ESCC.     

Tumorigenic suppression of a human cutaneous squamous cell carcinoma cell line in the nude mouse skin graft assay.

The development of human squamous cell carcinomas has been associated with a number of genetic alterations involving chromosome 11, including cytogenetic and allelic deletions as well as amplification of genes in the 11q13 region. To determine the relevance of chromosome 11 in the formation of tumors of stratified squamous epithelial origin, we have introduced, via microcell fusion, a normal human chromosome 11 into the cutaneous squamous cell carcinoma cell line A3886TGc2. The ability of chromosome 11 to modulate the tumorigenicity of A3886TGc2 was evaluated first by inoculating cells s.c. in nude mice. All hybrids remained tumorigenic but exhibited longer tumor latencies than the parent, a result previously observed by other laboratories. We then tested our epidermally derived hybrids in the more physiologically relevant environment of the nude mouse skin graft system. The tumorigenic phenotype of three of four chromosome 11 hybrids placed into nude mouse skin grafts was completely suppressed. Polymerase chain reaction amplification of DNA from normal skin present at the suppressed graft sites failed to detect the introduced human cells. This information indicates that the normal skin is of mouse origin and suggests that the chromosome 11 microcell hybrids did not differentiate in vivo, but most likely failed to survive. We propose that external environmental factors present at the site of inoculation modulate the tumorigenic potential of these cells.     

Hexokinase 2 overexpression promotes the proliferation and survival of laryngeal squamous cell carcinoma

Proliferating cancer cells preferentially use anaerobic glycolysis rather than oxidative phosphorylation for energy production. Hexokinase 2 (HK2) is highly expressed in many malignant cells and is necessary for anaerobic glycolysis. The role of HK2 in laryngeal squamous cell carcinoma (LSCC) is unknown. In this study, the expression of HK2 in LSCC was investigated and the effect of inhibiting HK2 expression with small hairpin RNA (shRNA) on tumor growth was investigated. Using immunohistochemistry, HK2 expression was assessed in LSCC tissues. Human laryngeal carcinoma Hep-2 cells were stably transfected with a plasmid expressing HK2 shRNA (pGenesil-1.1-HK2) and were compared to control cells with respect to the cell cycle, cell viability, apoptosis, and their ability to form xenograft tumors. HK2 expression was significantly higher in LSCC than in papilloma or glottis polypus. Tumor samples of higher T, N, and TNM stage often had stronger HK2 staining. HK2 shRNA reduced HK2 mRNA, protein levels, and HK activity in Hep-2 cells. HK2 cells expressing shRNA demonstrated a higher G0–G1 ratio, increased apoptosis, and reduced viability. Xenograft tumors derived from cells expressing HK2 shRNA were smaller and had lower proliferation than those from untransfected or control-plasmid-transfected cells. In conclusion, depletion of HK2 expression resulted in reduced xenograft tumor development likely by reducing proliferation, altering the cell cycle, reducing cell viability and activating apoptosis. These data suggest that HK2 plays an important role in the development of LSCC and represents a potential therapeutic target for LSCC.     

Novel retinoblastoma mutation abrogating the interaction to E2F2/3, but not E2F1, led to selective suppression of thyroid tumors

Mutant mouse models are indispensable tools for clarifying gene functions and elucidating the pathogenic mechanisms of human diseases. Here, we describe novel cancer models bearing point mutations in the retinoblastoma gene (Rb1) generated by N‐ethyl‐N‐nitrosourea mutagenesis. Two mutations in splice sites reduced Rb1 expression and led to a tumor spectrum and incidence similar to those observed in the conventional Rb1 knockout mice. The missense mutant, Rb1^D326V/+, developed pituitary tumors, but thyroid tumors were completely suppressed. Immunohistochemical analyses of thyroid tissue revealed that E2F1, but not E2F2/3, was selectively inactivated, indicating that the mutant Rb protein (pRb) suppressed thyroid tumors by inactivating E2F1. Interestingly, Rb1^D326V/+ mice developed pituitary tumors that originated from the intermediate lobe of the pituitary, despite selective inactivation of E2F1. Furthermore, in the anterior lobe of the pituitary, other E2F were also inactivated. These observations show that pRb mediates the inactivation of E2F function and its contribution to tumorigenesis is highly dependent on the cell type. Last, by using a reconstitution assay of synthesized proteins, we showed that the D326V missense pRb bound to E2F1 but failed to interact with E2F2/3. These results reveal the effect of the pRb N‐terminal domain on E2F function and the impact of the protein on tumorigenesis. Thus, this mutant mouse model can be used to investigate human Rb family‐bearing mutations at the N‐terminal region.     

Increased Cdc7 expression is a marker of oral squamous cell carcinoma and overexpression of Cdc7 contributes to the resistance to DNA-damaging agents

Cdc7-Dbf4 kinase (Dbf4-dependent kinase, DDK) is an essential factor of DNA replication and DNA damage response (DDR), which is associated with tumorigenesis. However, Cdc7 expression has never been associated to the outcome of oral squamous cell carcinoma (OSCC) patients, and the mechanism underlying cancer cell survival mediated by Cdc7 remains unclear. The Cdc7 protein expression of 105 OSCC tumor and 30 benign tissues was examined by immunohistochemistry assay. Overall survival rates of 80 OSCC patients were measured using Kaplan–Meier estimates and the log-rank tests. Cdc7 overexpression by adenovirus system was used to scrutinize the underlying mechanism contributed to cancer cell survival upon DDR. In silico analysis showed that increased Cdc7 is a common feature of cancer. Cdc7 overexpression was found in 96 of 105 (91.4%) studied cases of OSCC patients. Patients with higher Cdc7 expression, either categorized into two groups: Cdc7 high expression (2+ to 3+) versus Cdc7 low expression (0 to 1+) [hazard ratios (HR) = 2.6; 95% confidence interval (CI) = 1.28–5.43; P = 0.0087] or four groups (0 to 3+) [HR = 1.71; 95% CI = 1.20–2.44; P = 0.0032], exhibited a poorer outcome. Multivariate analysis showed that Cdc7 is an independent marker for survival prediction. Overexpressed Cdc7 inhibits genotoxin-induced apoptosis to increase the survival of cancer cells. In summary, Cdc7 expression, which is universally upregulated in cancer, is an independent prognostic marker of OSCC. Cdc7 inhibits genotoxin-induced apoptosis and increases survival in cancer cells upon DDR, suggesting that high expression of Cdc7 enhances the resistance to chemotherapy.     

NUCKS1 overexpression is a novel biomarker for recurrence-free survival in cervical squamous cell carcinoma

Nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS1) is overexpressed in various cancer tissues and may therefore contribute to oncogenesis. However, the status of NUCKS1 expression in cervical squamous cell carcinoma (CSCC) remains unknown. Immunohistochemistry was used to determine the expression of NUCKS1 protein in 30 cervical intraepithelial neoplasias (CINs) and 125 CSCCs compared with 20 normal cervical specimens. The correlationships of NUCKS1 protein overexpression with the clinicopathologic characteristics and clinical outcomes in patients with CSCC were analysed. The status of NUCKS1 expression was negative or weak in normal tissues, but high in 21 (70.0 %) CINs and in 44 (35.2 %) CSCCs. NUCKS1 overexpression was associated with advanced International Federation of Gynaecology and Obstetrics stage (P?=?0.016), poor histologic grade (P?=?0.040), large tumour size (P?=?0.016), parametrial involvement (P?=?0.025), deep stromal infiltration (P?=?0.043), lymph node metastasis (P?=?0.034) and recurrence (P?P?=?0.034). In conclusion, NUCKS1 overexpression may be associated with tumour progression and recurrence in CSCCs and may thus serve as a new molecular marker for the prediction of RFS in these patients.