Multigene analysis of Rb pathway and apoptosis control in esophageal squamous cell carcinoma identifies patients with good prognosis

Cellular senescence in cancer: clinical detection and prognostic implications

Cellular senescence is a state of stable cell-cycle arrest with secretory features in response to cellular stress. Historically, it has been considered as an endogenous evolutionary homeostatic mechanism to eliminate damaged cells, including damaged cells which are at risk of malignant transformation, thereby protecting against cancer. However, accumulation of senescent cells can cause long-term detrimental effects, mainly through the senescence-associated secretory phenotype, and paradoxically contribute to age-related diseases including cancer. Besides its role as tumor suppressor, cellular senescence is increasingly being recognized as an in vivo response in cancer patients to various anticancer therapies. Its role in cancer is ambiguous and even controversial, and senescence has recently been promoted as an emerging hallmark of cancer because of its hallmark-promoting capabilities. In addition, the prognostic implications of cellular senescence have been underappreciated due to the challenging detection and sparse in and ex vivo evidence of cellular senescence in cancer patients, which is only now catching up. In this review, we highlight the approaches and current challenges of in and ex vivo detection of cellular senescence in cancer patients, and we discuss the prognostic implications of cellular senescence based on in and ex vivo evidence in cancer patients.

Loss of Concurrent Regulation of the Expression of BIF-1, BAX, and Beclin-1 in Primary and Metastatic Melanoma

Melanoma is one of the most aggressive and drug-resistant cancers. Despite novel promising therapeutic strategies, the prognosis of metastatic melanoma patients remains poor and it is often associated with high relapse rates. Endophilin B1, also known as BIF-1, is a multifunctional protein involved in several biological processes such as autophagy and apoptosis. BIF-1 promotes apoptosis through binding to BAX and its translocation to the mitochondrial outer membrane. On the other hand, BIF-1 can interact with Beclin-1 through UVRAG to promote autophagy. Several reports suggest an ambiguous role of BIF-1 in cancer development and progression. For example, it has been demonstrated that the expression of BIF-1 is reduced in both primary and metastatic melanoma and that the reduction of BIF-1 expression is associated with reduced overall survival of melanoma patients. Here we show that the expression of Beclin-1 and active form of BAX are also reduced in the melanoma patients. However, while we observed strong positive correlations between the expression of BIF-1 and Beclin-1 as well as between BIF-1 and BAX in benign nevi, these correlations were lost in the primary and metastatic melanoma cells. These data indicate disruption in the proximal molecular mechanisms which regulate expression of BIF-1, Beclin-1, and BAX in the primary and metastatic melanoma.

Clinical and Prognostic Implications of P21 (WAF1/CIP1) Expression in Patients with Esophageal Cancer: A Systematic Review and Meta-Analysis

Background

Previous studies have demonstrated that P21 (WAF1/CIP1) is a valuable prognostic factor in several malignant tumors. However, it is not known whether P21 can predict the prognosis in patients with esophageal cancer (EC). The aim of this research was to investigate the contribution of P21 expression to the clinicopathological characteristics and of EC.

Methods

A systematic review and meta-analysis of study focusing on P21 expression, clinicopathological characteristics, and clinical outcomes in patients with EC was performed using seven databases (PubMed, Embase, Web of Science, and four Chinese databases). Pooled hazard ratios and odds ratios were used to explore the association between P21 expression, clinicopathological characteristics, and outcomes in patients with EC. The heterogeneity of the studies was classified by the I ² statistic. The sensitivity analysis was then utilized to assess the robustness of the results. Finally, the funnel plot and Begg's test were used to evaluate the publication bias.

Results

Forty-five studies with 3098 patients were eligible for inclusion in the meta-analysis. Thirty of these studies reported on clinicopathological characteristics and 15 on clinical outcomes. The pooled hazard ratio of 1.456 (95% confidence intervals 1.033-2.053, P = 0.032) for overall survival indicated that a low P21 expression level was an unfavorable prognostic factor for a clinical outcome in patients with EC. Furthermore, the pooled odds ratio confirmed an association between decreased P21 expression and poor clinicopathological characteristics, including differentiation, lymph node metastasis, invasion, and higher grade and clinical stage. Notably, high P21 expression was a significant predictor of a favorable response to chemotherapy. There was no evidence of publication bias.

Conclusion

Reduced P21 expression is associated with a poor outcome in patients with EC.

The prognostic value of cyclin D1 expression in the survival of cancer patients: A meta-analysis

BACKGROUND

The relationship between the expression of cyclin D1 and cancer prognosis and outcomes in different malignancies has not been fully elucidated.

AIMS

In the presented meta-analysis, we assessed the association between the expression level of cyclin D1 with overall survival (OS) in several cancers.

METHODS

Eligible studies were identified using PubMed, EMBase, Scopus, Web of Sciences and Cochrane Library databases. For the prognostic meta-analysis, study-specific hazard ratios (HRs) of tissue cyclin D1 for survival were obtained. Finally we pooled data derived from one hundred and eight studies comprising 19,224 patients with 10 different cancer types.

RESULTS

In the pooled analysis, high expression of cyclin D1 was significantly related to a poor OS with a pooled HR of 1.11 (95% CI: 1.02-1.20, P = 0.015; random-effects). Sub-group analysis revealed that high expression of cyclin D1 was related to worse OS of head and neck cancers (HR = 2.08, 95% CI: 1.75-2.47; P < 0.001), but not in breast (HR = 1.033, 95% CI: 0.873-1.223, P = 0.702), gastrointestinal (HR = 1.025, 95% CI:0.824-1.275; P = 0.825), bladder (HR = 0.937, CI: 0.844-1.041; P = 0.225) and in lung cancer patients (HR = 1.092, CI: 0.819-1.455; P = 0.549).

CONCLUSION

Further large, prospective, and well-designed trials are warranted to elucidate the precise clinical importance of cyclin D1 overexpression in the prognosis of cancer patients receiving different treatment regimens.

Identifying Mutually Exclusive Gene Sets with Prognostic Value and Novel Potential Driver Genes in Patients with Glioblastoma

The pathogenesis and prognosis of glioblastoma (GBM) remain poorly understood. Mutual exclusivity analysis can distinguish driver genes and pathways from passenger ones. The purpose of this study was to identify mutually exclusive gene sets (MEGSs) that have prognostic value and to detect novel driver genes in GBM. The genomic alteration profile and clinical information were derived from The Cancer Genome Atlas, and the MEGSA method was used to identify the MEGS. Next, we performed survival analysis and constructed a risk prediction model for prognostic stratification. Leave-one-out cross-validation and permutation test were used to evaluate its performance. Finally, we identified 21 statistically significant MEGSs. We found that the MEGS in the RB pathway was significantly associated with poor prognosis, after adjusting for age and gender (HR = 1.837, 95% CI: 1.192-2.831). Based on the risk prediction model, 208 (80.9%) and 49 (19.1%) patients were assigned to high- and low-risk groups, respectively (log-rank: p < 0.001, adjusted p=0.001). Additionally, we found that SPTA1, a novel gene involved in the MEGS, was mutually exclusive with members of cell cycle, P53, and RB pathways. In conclusion, the MEGS in the RB pathway had considerable clinical value for GBM prognostic stratification. Mutated SPTA1 may be involved in GBM development.

Polymorphism rs2395655 affects LEDGF/p75 binding activity and p21WAF1/CIP1 gene expression in esophageal squamous cell carcinoma

p21WAF1/CIP1 (p21) plays critical roles in cell‐cycle regulation and DNA repair and is transcriptionally regulated through p53‐dependent or ‐independent pathways. Bioinformatic analysis predicated one stress‐response element (STRE) implicated in single nucleotide polymorphism (SNP) rs2395655 of the p21 promoter. Here, we investigated the transcriptional regulatory function of rs2395655 variant genotype and analyzed its associations with the p21 expression and clinical outcomes in esophageal squamous cell carcinoma (ESCC) patients. Luciferase assay results showed significantly increased transcriptional activity of the rs2395655 G allele‐containing p21 promoter compared with rs2395655 A allele‐containing counterpart, especially in ESCC cells with ectopic LEDGF/p75 expression. Furthermore electrophoretic mobility shift assay using the rs2395655 G or A allele‐containing probe and chromatin immunoprecipitation assay with specific anti‐LEDGF/p75 antibody indicated the potential binding activity of LEDGF/p75 with the STRE element implicated in rs2395655 G allele of the p21 promoter. Subsequent specific RNA interference‐mediated depletion or ectopic expression of LEDGF/p75 caused obviously down‐ or up‐regulated expression of p21 mRNA in ESCC cells harboring rs2395655 GG genotype but not cells with rs2395655 AA genotype. Furthermore, rs2395655 GG genotype carriers showed significantly elevated p21 protein expression and conferred survival advantage in both univariate and multivariate analyses in total 218 ESCC patients. Our findings suggest that LEDGF/p75 regulates the p21 expression in ESCC cells through interacting with STRE element implicated in polymorphism rs2395655 and the elevated p21 protein expression and rs2395655GG genotype may serve as positive prognostic factors for ESCC patients.

Immunohistochemical prognostic markers of esophageal squamous cell carcinoma: a systematic review

Background

Esophageal squamous cell carcinoma (ESCC) is an aggressive malignancy, with a high incidence and poor prognosis. In the past several decades, hundreds of proteins have been reported to be associated with the prognosis of ESCC, but none has been widely accepted to guide clinical care. This study aimed to identify proteins with great potential for predicting prognosis of ESCC.

Methods

We conducted a systematic review on immunohistochemical (IHC) prognostic markers of ESCC according to the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Guidelines. Literature related to IHC prognostic markers of ESCC were searched from PubMed, Embase, Web of Science, and Cochrane Library until January 30th, 2017. The risk of bias of these original studies was evaluated using the Quality in Prognosis Studies (QUIPS) tool.

Results

We identified 11 emerging IHC markers with reproducible results, including eight markers [epidermal growth factor receptor (EGFR), Cyclin D1, vascular endothelial growth factor (VEGF), Survivin, Podoplanin, Fascin, phosphorylated mammalian target of rapamycin (p-mTOR), and pyruvate kinase M2 (PKM2)] indicating unfavorable prognosis and 3 markers (P27, P16, and E-cadherin) indicating favorable prognosis of ESCC.

Conclusion

Strong evidence supports that these 11 emerging IHC markers or their combinations may be useful in predicting prognosis and aiding personalized therapy decision-making for ESCC patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s40880-017-0232-5) contains supplementary material, which is available to authorized users.

P21, COX-2, and E-cadherin are potential prognostic factors for esophageal squamous cell carcinoma

Much research effort has been devoted to identifying prognostic factors for esophageal squamous cell carcinoma (ESCC) by immunohistochemistry; however, no conclusive findings have been reached thus far. We hypothesized that certain molecules identified in previous studies might serve as useful prognostic markers for ESCC. Therefore, the aim of the current study was to validate the most relevant markers showing potential for ESCC prognosis in our prospective esophageal cancer database. A literature search was performed using the PubMed database for papers published between 1980 and 2015 using the following key words: 'esophageal cancer,' 'prognosis,' and 'immunohistochemistry.' Literature selection criteria were established to identify the most widely studied markers, and we further validated the selected markers in a cohort from our single-surgeon team, including 153 esophageal cancer patients treated from 2000 to 2010. A total of 1799 articles were identified, 82 of which met the selection criteria. Twelve markers were found to be the most widely studied, and the validation results indicated that only P21, COX-2, and E-cadherin were independent prognostic factors for ESCC patients in this series. The systemic review and cohort validation suggest that P21, COX-2, and E-cadherin are potential prognostic factors for ESCC, paving the way for more targeted prospective validation in the future.

Relationship between P53 status and prognosis and clinicopathologic characteristics in esophagus squamous cell carcinoma: A systematic review

AIM: To evaluate the prognostic role of p53 status and its relationship with clinicopathologic characteristics in esophagus squamous cell carcinoma (ESCC).

METHODS: A systematic search of PubMed, SCI-Ex-panded, EMBASE, the Cochrane library, China National Knowledge Infrastructure (CNKI), Chinese Biomedical Database (CBM), and science and technology periodical database (VIP) was performed. Related references were also searched for additional clinical studies. Two reviewers independently performed screening of identified studies and data extracting according to inclusion and exclusion criteria. The quality assessment was conducted on the basis of the Newcastle-Ottawa Quality Assessment Scale (NOS). The evaluation of the publication bias of the included studies and data synthesis were performed with RevMan 5.3. A fixed-effect or random effects model was adopted according to heterogeneity.

RESULTS: A total of 85 studies involing 8825 cases met the inclusion criteria. The experimental group (4608 cases) was positive for either p53 gene mutation or protein expression, and the control group (4217 cases) was negative for either p53 gene mutation or protein expression. The pooled hazard ratio (HR) for OS was 1.35 (95%CI: 1.23-1.47, P < 0.00001; heterogeneity: P = 0.39, I² = 5%). The pooled risk ratio (RR) for the 5-year and 3-year survival rates was 0.73 (95%CI: 0.62-0.87, P = 0.0003; heterogeneity: P = 0.001, I² = 50%) and 0.87 (95%CI: 0.74-1.02, P = 0.09; heterogeneity: P = 0.28, I² = 18%). p53 gene mutation or protein expression was significantly associated with poorer T stage (RR = 1.09, P = 0.004), N stage (RR = 1.24, P < 0.00001), M stage (RR = 1.65, P < 0.00001), TNM stage (RR = 1.25, P < 0.00001) and differentiation degree (RR = 1.06, P = 0.03). However, there were no association between P53 status and vascular invasion, tumor location, size, age or gender in ESCC (P>0.05).

CONCLUSION: p53 gene mutation or protein expression abnormality is a marker of poor prognosis in patients with ESCC. Meantime, patients with P53 abnormalities are associated with higher depth of invasion, higher rate of lymph node metastasis and distant metastasis, later TNM stage, and poorer grade of differentiation.

Cyclin D1, retinoblastoma and p16 protein expression in carcinoma of the gallbladder

BACKGROUND

Cancer of the gallbladder is a relatively rare neoplasm with a poor prognosis. The exact mechanisms of its genesis are not known and very little information is available on molecular events leading to labeling this as an orphan cancer.

MATERIALS AND METHODS

In this prospective case control study we evaluated the expression of p16, pRb and cyclin D1 by immunohistochemistry to study the G1-S cell-cycle check point and its possible role in gallbladder carcinogenesis. A total of 25 patients with gallbladder carcinoma (group I), 25 with cholelithiasis (group II) and 10 normal controls. were enrolled.

RESULTS

Cyclin D1 expression was seen in 10 (40%) patients each with carcinoma and cholelithiasis while only in 2 (20%) of the normal gallbladders but differences were not statistically significant (p value=0.488). p16 was expressed in 12% patients of carcinoma of the gallbladder and 28% of cholelithiasis, however this difference was not statistically significant (p value=0.095). Retinoblastoma protein was found to be expressed in 50% of normal gallbladders and 6 (24%) of carcinoma and 8 (32%) of gallstones. The present study failed to demonstrate any conclusive role of cyclin D1/RB/ p16 pathway in carcinoma of the gallbladder.

CONCLUSIONS

The positive relation observed between tumor metastasis and cyclinD1 expression and p16 with nodal metastasis suggested that higher cyclin D1/p16 expression may act as a predictive biomarker for aggressive behavior of gallbladder malignancies.

Systematic review and meta-analysis of tumor biomarkers in predicting prognosis in esophageal cancer

BACKGROUND

Esophageal cancer (EC) is a frequently occurring cancer with poor prognosis despite combined therapeutic strategies. Many biomarkers have been proposed as predictors of adverse events. We sought to assess the prognostic value of biomarkers in predicting the overall survival of esophageal cancer and to help guide personalized cancer treatment to give patients the best chance at remission.

METHODS

We conducted a systematic review and meta-analysis of the published literature to summarize evidence for the discriminatory ability of prognostic biomarkers for esophageal cancer. Relevant literature was identified using the PubMed database on April 11, 2012, and conformed to the REMARK criteria. The primary endpoint was overall survival and data were synthesized with hazard ratios (HRs).

RESULTS

We included 109 studies, exploring 13 different biomarkers, which were subjected to quantitative meta-analysis. Promising markers that emerged for the prediction of overall survival in esophageal squamous cell cancer included VEGF (18 eligible studies, n=1476, HR=1.85, 95% CI, 1.55-2.21), cyclin D1 (12 eligible studies, n=1476, HR=1.82, 95% CI, 1.50-2.20), Ki-67 (3 eligible studies, n=308, HR=1.11, 95% CI, 0.70-1.78) and squamous cell carcinoma antigen (5 eligible studies, n=700, HR=1.28, 95% CI, 0.97-1.69); prognostic markers for esophageal adenocarcinoma included COX-2 (2 eligible studies, n=235, HR=3.06, 95% CI, 2.01-4.65) and HER-2 (3 eligible studies, n=291, HR=2.15, 95% CI, 1.39-3.33); prognostic markers for uncategorized ECs included p21 (9 eligible studies, n=858, HR=1.27, 95% CI, 0.75-2.16), p53 (31 eligible studies, n=2851, HR=1.34, 95% CI, 1.21-1.48), CRP (8 eligible studies, n=1382, HR=2.65, 95% CI, 1.64-4.27) and hemoglobin (5 eligible studies, n=544, HR=0.91, 95% CI, 0.83-1.00).

CONCLUSIONS

Although some modest bias cannot be excluded, this review supports the involvement of biomarkers to be associated with EC overall survival.

Invasive and prognostic significance of pRB in esophageal squamous cell carcinoma: a meta-analysis

This paper investigates the association between protein retinoblastoma (pRB) loss and the T,N stage and prognosis in esophageal squamous cell carcinomas (ESCCs) using meta-analysis. We conducted a meta-analysis of 16 studies, comprising 1,117 patients to clarify this issue. All the studies searched by the electronic literature PubMed and http://www.KJEBM.com, which had been published during the period from January 1996 to January 2012 according to the inclusion criteria. Summary odds ratios (OR) were calculated using fixed or random-effects models. The summary odds ratios (ORs) for pRB inactive were 0.64 (95% confidence interval [CI]:0.45-0.91, P = 0.01) for T1/T2 versus T3/T4 tumors; summary OR = 0.69 (95% CI:0.51-0.94, P = 0.02) for N0 versus N1 tumors. The association between pRB loss and prognosis was examined in nine studies, and the summary hazard ratio was 1.39 (95% CI:1.11-1.74, P = 0.004). pRB inactive was significant associated with T3/T4 tumors and N1 stage as well as adverse prognosis for ESCCs. It appears warranted to prospectively validate that pRB loss may be used for subdividing the T,N stage evaluation of patients with ESCCs, and these patients may be the preponderant people for individualized treatment or target therapy.

Correlation between expression of apoptosis modulators Smac and Cyt C and prognosis in esophageal squamous cell carcinoma

AIM: To investigate the expression of second mitochondria-derived activator of caspase (Smac) and cytochrome C (Cyt C) in esophageal squamous cell carcinoma (ESCC) and to analyze their prognostic significance.

METHODS: Semiquantitive immunochemistry was performed to detect the expression of Smac and Cyt proteins in 85 cases of ESCC, matched tumor-adjacent esophageal tissue, and normal esophageal tissue.

RESULTS: The positive rates of Smac expression in ESCC, tumor-adjacent esophageal tissue and normal esophageal tissue were 63.75%, 92.50% and 77.50%, respectively, with a significant difference among the three groups (Hc = 28.703, P < 0.05). The positive rates of Cyt C expression also differed significantly among ESCC, tumor-adjacent esophageal tissue and normal esophageal tissue (61.25% vs 90.00% vs 72.50%; Hc = 24.720, P < 0.05). The expression of Smac/ Diablo and Cyt C was not correlated with tumor histological differentiation and infiltration depth in ESCC (both P > 0.05), but was correlated with lymph node metastasis (P < 0.05). Expression of Cyt C protein was positively correlated with that of Smac protein in ESCC (r = 0.806, P < 0.01).

CONCLUSION: The expression of Smac/Diablo and Cyt C protein closely correlates with lymph node metastasis in ESCC. Smac/Diablo is lowly expressed in ESCC, and expression of Smac/Diablo positively correlates with that of Cyt C.

Clinicopathological and prognostic role of cyclin D1 in esophageal squamous cell carcinoma: a meta-analysis

Cyclin D1 is one of the most commonly over-expressed oncogenes; however, its role in esophageal squamous cell carcinoma (ESCC) remains controversial. We conducted a meta-analysis of 20 studies, comprising 2,041 patients to clarify this issue. In all studies, paraffin-embedded surgical specimens were collected and the status of cyclin D1 was determined by immunohistochemistry (IHC). The combined odds ratios (Ors) for cyclin D1 expression were 0.74 (95% confidence interval [CI]: 0.58-0.93) for well and moderately differentiated versus poorly differentiated tumors, 0.65 (95% CI: 0.45-0.94) for T1/T2 versus T3/ T4 tumors, 0.59 (95% CI: 0.39-0.90) for N0 versus N1 tumors, and 0.48 (95% CI: 0.33-0.71) for stage I/II versus stage III/IV diseases, respectively. The association between cyclin D1 expression and prognosis was examined in 10 studies, and the combined hazard ratio was 1.78 (95% CI: 1.49-2.12). Cyclin D1 expression level detected by IHC is associated with worst clinicopathological features and prognosis for ESCC.

Association of p53/p21 expression with cigarette smoking and prognosis in esophageal squamous cell carcinoma patients

AIM: To investigate the expression of p53 and p21 and associations with possible risk factors, such as cigarette smoking, in esophageal squamous cell carcinoma (ESCC) in northeastern Iran, a region with a high incidence of ESCC.

METHODS: The expression of p53 and p21 proteins was investigated immunohistochemically in tumor tissue from 80 ESCC patients and in 60 available paraffin-embedded blocks of adjacent normal specimens from the cases, along with normal esophageal tissue from 80 healthy subjects.

RESULTS: Positive expression of p53 protein was detected in 56.2% (45/80) of ESCC cases, and in none of the normal esophageal tissue of the control group (P < 0.001). Furthermore, 73.8% (59/80) of ESCC cases and 43.8% (35/80) of controls had positive expression of p21 protein (P < 0.001). Cigarette smoking was significantly associated with p53 over-expression in ESCC cases (P = 0.010, OR = 3.64; 95% CI: 1.32-10.02). p21 over-expression was associated with poorer clinical outcome among the ESCC patients (P = 0.009).

CONCLUSION: Over-expression of p53 in association with cigarette smoking may play a critical role in ESCC carcinogenesis among this high-risk population of northeastern Iran. Furthermore, p21 over-expression was found to be associated with poor prognosis, specifically in the operable ESCC patients.

Cotransfection of the p15INK4B and p21WAF1 genes synergistically inhibits proliferation and promotes apoptosis in human esophageal squamous cell carcinoma cell line EC109

AIM: To investigate the synergistic effects of p15^INK4B (p15) and p21^WAF1 (p21) gene cotransfection on the proliferation and apoptosis of human esophageal squamous cell carcinoma EC109 cells.

METHODS: The recombinant plasmids pcDNA3.1(+)-p15 and pcDNA3.1(+)-p21 were introducted into EC109 cells by liposome-mediated transfection. The expression of p15 and p21 mRNA and protein was assayed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, respectively. Cell proliferation was measured by methyl thiazol tetrazolium (MTT) assay. Apoptotic cells were observed using a transmission electron microscope. Cell cycle distribution and apoptosis rate were measured by flow cytometry.

RESULTS: The proliferation of EC109 cells transfected with either of the two recombinant plasmids was significantly inhibited when compared with untransfected cells or cells transfected with empty plasmid. The proliferation of cotransfected cells was more significantly inhibited than that of cells transfected with either of the two recombinant plasmids. The percentages of cells in G₁ phase were significantly higher in cells transfected with either of the two recombinant plasmids than in cells transfected with empty plasmid and untransfected cells (60.52% ± 3.75% and 63.12% ± 2.89% vs 42.17% ± 5.30% and 41.38% ± 6.54%, respectively; all P < 0.01), while the percentages of cells in S phase were significantly lower in cells transfected with either of the two recombinant plasmids than in cells transfected with empty plasmid and untransfected cells (22.67% ± 1.25% and 17.96% ± 2.03% vs 30.96% ± 3.33% and 36.05% ± 1.78%, respectively; all P < 0.01). In cotransfected cells, the percentage of cells in G₁ phase significantly increased (72.83% ± 2.31% vs 60.52% ± 3.75% and 63.12% ± 2.89%, respectively; both P < 0.05), the percentage of cells in S phase significantly decreased (13.59% ± 2.59% vs 22.67% ± 1.25% and 17.96% ± 2.03%, respectively; both P < 0.05), and apoptosis rate was significantly elevated (21.21% ± 1.78% vs 4.32% ± 1.74% and 10.83% ± 2.40%, respectively; both P < 0.01) when compared with cells transfected with either of the two recombinant plasmids.

CONCLUSION: Cotransfection of the p15 and p21 genes synergistically inhibits proliferation and promotes apoptosis in EC109 cells.

Silencing of tumor necrosis factor receptor 1 by siRNA in EC109 cells affects cell proliferation and apoptosis

Tumor necrosis factor receptor 1 (TNFR1) is a membrane receptor able to bind TNF-α or TNF-β. TNFR1 can suppress apoptosis by activating the NF-κB or JNK/SAPK signal transduction pathway, or it can induce apoptosis through a series of caspase cascade reactions; the particular effect may depend on the cell line. In the present study, we first showed that TNFR1 is expressed at both the gene and protein levels in the esophageal carcinoma cell line EC109. Then, by applying a specific siRNA, we silenced the expression of TNFR1; this resulted in a significant time-dependent promotion of cell proliferation and downregulation of the apoptotic rate. These results suggest that TNFR1 is strongly expressed in the EC109 cell line and that it may play an apoptosis-mediating role, which may be suppressed by highly activated NF-κB.

Expression profiles of early esophageal squamous cell carcinoma by cDNA microarray

An effective way to decrease the mortality rate in esophageal cancer (EC) is to provide diagnosis and treatment for early EC patients. Identification of molecular markers would be helpful for early diagnosis. In this study, we obtained the gene expression profile of early esophageal squamous cell carcinoma (ESCC) and further screened molecular markers that might be useful in early diagnosis and treatment. RNA extracted from EC cancer tissues and matched normal esophageal epithelium of four EC patients were analyzed using whole-genome microarrays. Welch's t-test was applied to normalized data to identify genes expressed differently between cancer and normal tissues. Significantly differentially expressed genes were classified according to gene ontology. Gene mapping software was used to identify pathways involving the genes that were significantly changed. Among the 54,613 gene transcripts and variants analyzed, 367 were differentially expressed between early ESCC and normal esophageal epithelium (Welch's t-test, P<0.01). Specifically, 104 genes were significantly upregulated and 263 were downregulated in early ESCC, compared with normal esophageal epithelium. Functional gene sets expressed differentially between ESCC cancer and normal tissues included those involved in gene transcription, cell proliferation, motility, apoptosis, and metabolism (specifically, pathways of cell apoptosis, the cell cycle, G protein, and TGF-beta signal transduction). We conclude that a large number of genes are involved in the occurrence and development of early ESCC and take part in various cell processes and pathways. The present findings contribute theoretical information for further screening of genes related to early ESCC.

Loss of nuclear p27 expression and its prognostic role in relation to cyclin E and p53 mutation in gastroenteropancreatic neuroendocrine tumors

PURPOSE

Gastroenteropancreatic neuroendocrine tumors (GEP-NET) are classified by the WHO, yet its prognostic value needs to be confirmed. Therefore, we aimed to determine the prognostic role of cell cycle key regulatory genes p53, p27kip1 (p27), and cyclin E in this tumor entity.

EXPERIMENTAL DESIGN

Tumor specimen from 89 patients with a complete follow-up were studied immunohistochemically for p27 and cyclin E expression and for p53 mutations. The functional relevance of p27 was evaluated in the neuroendocrine cell lines BON1 (human) and INS1 (rat) by the use of small interfering RNA.

RESULTS

Twenty-six of 29 benign, well-differentiated endocrine tumors (WHO class 1) showed a high expression (> 50%) of p27, whereas all 10 poorly differentiated endocrine carcinomas (WHO class 3) displayed a low expression of p27. Metastatic well-differentiated endocrine carcinomas (WHO class 2) showed a low p27 expression in 20 of 50 (40%) patients, which conferred a poor prognosis (median survival, 57 versus 140 months; P = 0.037). This prognostic dichotomy was improved by the use of a combination of p27 and cyclin E (high cyclin E/low p27 versus low cyclin E/high p27: median survival 53 months versus not reached; P = 0.0044). p53 mutations were rare (1 of 10 poorly differentiated endocrine carcinomas).

CONCLUSIONS

Loss of p27 and overexpression of cyclin E play a critical role in the aggressiveness of gastroenteropancreatic neuroendocrine tumors. This coincides with increased cell cycle progression. We propose a discussion whether to incorporate the immunohistochemical expression of p27 into a revised classification to individualize therapeutic strategies in this tumor entity.

Novel targeted therapies for advanced esophageal cancer

Esophageal cancer is highly aggressive and is the sixth leading cause of cancer death worldwide. Recent advances in multimodality chemoradiotherapy and surgery has improved survival in patients with loco-regional disease, but most patients with advanced stage esophageal cancer have a poor prognosis. Elucidation of the processes involved in esophageal carcinogenesis has identified a number of promising novel targets for therapy. This review focuses on the current status of targeted therapies with potential application to the treatment of advanced esophageal and gastroesophageal junction cancer. The future challenge is to confirm the efficacy of these targeted agents in appropriately selected esophageal cancer patients, and successfully integrate these agents into effective therapies for all stages and subtypes of disease.

Downregulation of cell cycle modulators p21, p27, p53, Rb and proapoptotic Bcl-2-related proteins Bax and Bak in cutaneous melanoma is associated with worse patient prognosis: preliminary findings

BACKGROUND

Cutaneous melanoma is a tumor with high metastatic potential, but the mechanisms leading to progression are still not fully understood. To provide further molecular basis for understanding the progression of melanoma, the aim of this study was to examine the expression pattern of cell cycle modulators (p21, p27, p53 and Rb) and proapoptotic multidomain Bcl-2 related proteins (Bax and Bak) and to analyze its differences in patients with and without progression stages.

METHODS

We have studied 31 patients with cutaneous melanoma at stage IIa (Breslow thickness 1.5-4.0 mm), and follow them for 10-year period. Eighteen of these patients developed metastasis. The determination of selected molecular markers participating in cell cycle regulation and apoptosis was performed by immunohistochemistry.

RESULTS

We have observed a significant increase in the loss of expression of the Bax, Bak, p21, p27, p53 and Rb. The analysis of the relationship between these downregulated markers and Breslow thickness showed significant positive correlation (r=0.556, p=0.029) and predictive value if thickness below 2.3 mm (OR=3.0, 95% CI=0.312-28.84).

CONCLUSIONS

Our study showed that the downregulation of the markers associated with cell cycle control and apoptosis is of great value in predicting malignant transformation and in assessing the risk of metastases development for 10-year follow-up period.

Deregulated p21(WAF1) overexpression impacts survival of surgically resected esophageal squamous cell carcinoma patients

BACKGROUND

Prognostic effects of cell cycle regulation associated tumor suppressor genes for esophageal squamous cell carcinoma patients are controversial. Clarifying the effects of these genes is beneficial for optimizing patient's outcome.

METHODS

Forty esophageal squamous cell carcinoma patients were included in the study. Tissue samples were analyzed for cell proliferation, DNA content, mutation of p53 gene, and expression of p21 and p53 proteins. Prognostic effects of these parameters were assessed by multivariate analysis.

RESULTS

Seventy-five percent of tumors exhibited aneuploid DNA content. Significantly higher S-phase fractions were detected in tumor samples (p < 0.001). The p53 gene mutated in 52.5% (21 of 40) of tumor samples, p53 immunostaining was detected in 62.5% (25 of 40) of tumor tissues and 50% of tumors over expressed p21. Overexpression of p21 protein did not correlate with p53 gene status, but significantly correlated with abnormal DNA content (p = 0.028). Advanced pTNM stage, lymph node metastasis and p21 overexpression conferred survival disadvantages in univariate analysis (p = 0.013, 0.045 and 0.017, respectively). A Cox multivariable analysis revealed pTNM stage (IIB/III/IV vs. I/IIA; p = 0.024) associated with p21 overexpression (positive vs. negative; p = 0.035) as independent prognostic factors in esophageal squamous cell carcinomas. Surprisingly, p21 overexpression significantly compromised the survival of patients with mutated p53 gene (p = 0.035). However, no significant dismal effect of p21 overexpression can be seen in patients with wild-type p53 gene (p = 0.175).

CONCLUSIONS

Overexpression of p21 correlates with chromosomal instability and serves as an adverse prognostic predictor for patients with esophageal squamous cell carcinoma. Its adverse effect is more prominent when the p53 gene is mutated.

Lower expression of p14ARF and p16INK4a correlates with higher DNMT3B expression in human oesophageal squamous cell carcinomas

Oesophageal squamous cell carcinoma (ESCC) is one of the most common malignancies and is the sixth cause of cancer-related death in the world. Inactivation of cell-cycle regulating genes, such as p14ARF and p16INK4a, and cell adhesion genes, such as E-cadherin, is common in cancer, and results from genetic and/or epigenetic alterations. Therefore, we have analysed the mRNA expression of p14ARF, p16INK4a and E-cadherin in 17 matched ESCC and normal mucosal samples obtained from Brazilian patients by semi-quantitative RT-PCR. The expression of p14ARF and p16INK4a was absent or reduced in several ESCC samples. Hypermethylation of CpG islands, caused by the action of DNA methyltransferases (DNMTs), is a major form of epigenetic inactivation of the p14ARF and p16INK4a genes in tumours. Hence, we also investigated the mRNA expression of the human DNA methyltransferases in normal oesophageal mucosa and in the tumour matched samples. All DNMTs were constitutively expressed in the normal oesophageal mucosa but a significantly higher expression of DNMT3B was observed in the tumours. Data analysis by the Spearman rank test showed that the expression of DNMT3B was inversely correlated with that of p14ARF and p16INK4a. Our results suggest that DNMT3B over-expression may be involved in the suppression or lower expression of p14ARF and p16INK4a observed in ESCC.

Alvocidib (Flavopiridol) suppresses tumor growth in SCID mice with human esophageal cancer xenografts without inducing apoptosis

Alvocidib (Flavopiridol, HMR1275) is a potent inhibitor of multiple cyclin-dependent kinases and has been identified recently as an antitumor agent in several cancers. Previous studies have shown that alvocidib could potentially treat esophageal cancer in vitro. This study evaluates alvocidib for its ability to suppress tumor growth in severe combined immunodeficiency (SCID) mice bearing TE8 human esophageal squamous cell carcinoma (SCC) xenografts. Alvocidib treatment of 10mg/kg body weight reduced tumor volume significantly. Immunohistochemistry analysis of alvocidib-treated tumor sections showed significant reductions in cyclin D1, VEGF, and Rb levels. Alvocidib treatment did not cause a marked increase in apoptotic tumor cells by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) analysis, yet hematoxylin and eosin staining revealed tumor necrosis. In vivo investigation of alvocidib treatment confirmed antitumor activity in TE8 esophageal xenografts. These findings suggest that alvocidib could be a useful anti-cancer agent for esophageal cancer.

Loss of Proapoptotic Bcl-2-Related Multidomain Proteins in Primary Melanomas Is Associated with Poor Prognosis

Prognosis of primary melanoma is presently based on morphological parameters, mainly tumor thickness. However, more reliable prognostic markers are needed that allow a better stratification of patients, especially with regard to therapeutic options. Here, a retrospective study was performed on patients with primary superficial-spreading melanoma (SSM, n=44) or nodular melanoma (n=16) of 1.5-4 mm thickness. Thirty patients had survived the follow-up of 10 years, whereas the other 30 patients developed metastases. Tumor sections were analyzed by immunohistochemistry for the expression of regulators of the cell cycle (p21; retinoblastoma protein (pRb)), of the intrinsic or extrinsic proapoptotic pathways (p53; murine double minute gene 2 protein; tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-R1/DR4; TRAIL-R2/DR5) and of Bcl-2-related proteins (Bcl-2, Mcl-1, Bax, Bak, Bok), which regulate the common mitochondrial apoptotic pathway. In SSM, decrease of Bax and Bak was significantly correlated with a poor prognosis: high Bax was associated with 10-year survival rates of 68%, whereas low Bax resulted in only 26% survival, and high Bak was associated with 10-year survival rates of 62%, whereas low Bak resulted in only 10% survival. Regulators of apoptosis may therefore candidate for independent prognostic markers for primary melanomas. The study underlines the particular role of the mitochondrial apoptosis pathway and of proapoptotic Bcl-2-related proteins for melanoma progression.

Silencing of APAF-1 in B-CLL results in poor prognosis in the case of concomitant p53 mutation

Apoptosis protease-activating factor 1 (APAF-1), a transcriptional target of p53, is a cytosolic adaptor protein that links the mitochondrial apoptosis pathway to the caspase cascade. Here, we aimed to study the impact of APAF-1 expression levels on cell death induced by anticancer drugs or ionizing irradiation (IR) and disease prognosis in B-type chronic lymphocytic leukemia (B-CLL) patients. Samples from 138 patients with B-CLL were investigated for APAF-1 expression and p53 mutations. The results were related to survival data, in vitro cytotoxicity of various cytotoxic drugs and IR and clinico-pathological data. Variable APAF-1 expression was observed in all investigated B-CLL samples. Reduction in APAF-1 expression was observed at both mRNA and protein level indicating transcriptional silencing whereas mutation of p53 or the immunoglobulin heavy chain variable genes (IgH(V)) had no impact on APAF-1 expression. Surprisingly, APAF-1 loss did not result in resistance to cytotoxic therapies. Likewise, APAF-1 downregulation on its own showed no impact on disease prognosis. Nevertheless, a poor prognosis was observed in patients with loss of APAF-1 expression and additional p53 mutation. Thus, loss of APAF-1 may become relevant when additional core apoptosis signaling components are disrupted.

Analysis of neuroendocrine differentiation and the p53/BAX pathway in UICC stage III colorectal carcinoma identifies patients with good prognosis

BACKGROUND AND AIMS

Neuroendocrine differentiation is an independent prognostic factor in colorectal cancer. Moreover, an altered p53/BAX pathway is associated with a poor clinical outcome in Union Internationale Contre le Cancer (UICC) stage III disease. Because these markers are involved in different genetic events disrupted in colorectal cancer, we investigated the prognostic power of a multimarker analysis.

PATIENTS AND METHODS

Specimens were analyzed from 59 patients with UICC stage III disease who underwent surgery for colorectal adenocarcinoma at our institution and were followed up for 5 years or until death. Tumors were studied for both p53 mutation and BAX protein expression as well as for the expression of neuroendocrine markers. Statistical analysis of each marker alone or in combination was performed.

RESULTS

p53 status/BAX expression and neuroendocrine differentiation are not correlated in stage III colorectal cancers. However, the combination of both independent events identified a subgroup of patients with an excellent prognosis: Patients whose tumors were neuroendocrine marker-negative and who exhibited an intact p53/BAX pathway lived longer (mean survival, 93 months; range, 82-104 months) than patients whose tumors were either neuroendocrine marker-positive or whose tumors had a completely disrupted apoptotic pathway (41 months; range, 26-57 months; p<0.00001). In multivariate regression analysis, neuroendocrine marker-positive, p53 mutated, low-BAX-expressing tumors revealed an almost fivefold higher risk for earlier death (p<0.0001).

CONCLUSION

Disruption of the p53/BAX pathway is not pathognomonic for colorectal cancers with neuroendocrine differentiation. Both represent independent prognostic markers in UICC stage III disease. Therefore, the combined analysis of p53 status, BAX expression and neuroendocrine differentiation allows one to identify subgroups of patients with either very good or very poor prognosis.

Increased E2F-1 expression via tumour cell proliferation and decreased apoptosis are correlated with adverse prognosis in patients with squamous cell carcinoma of the oesophagus

BACKGROUND

The retinoblastoma (Rb) pathway, which governs cell cycle progression, is frequently genetically altered in cancer, causing deregulated expression of the E2F-1 transcription factor, which promotes DNA synthesis and cell cycle progression. Recent studies show that E2F-1 also participates in apoptosis induction in a p53 dependent or independent manner. Despite its crucial role and paradoxical effects on cell turnover, the function of E2F-1 in human cancer is unclear.

AIMS

To evaluate E2F-1 expression using immunohistochemistry in 43 surgically resected oesophageal squamous cell carcinoma (OSCC) specimens.

METHODS

This study analysed the association of E2F-1 with tumour cell proliferation and apoptosis and the upstream regulators modulating these processes, and its impact on patient outcome. Tumour cell proliferation and apoptosis were assessed as percentage of MIB-1 positive or apoptotic cells (MIB-1 labelling index (MI) and apoptotic index (AI)), respectively.

RESULTS

Entire specimens showed abnormal expression of one or more upstream regulators of pRb/E2F-1. Although E2F-1 positivity was not associated with the expression of upstream regulators, it showed a linear and positive correlation with MI but not AI. Patients with high MI, low AI, or high E2F-1 positivity had significantly shorter recurrence free survival. By multivariate analysis, high MI and low AI were independently associated with recurrence free survival, but E2F-1 was not.

CONCLUSIONS

Increased cell proliferation and decreased apoptosis are associated with adverse prognosis in patients with OSCC. Although E2F-1 remains a controversial prognostic factor, its expression was closely associated with tumour cell proliferation and might influence clinical outcome, mainly via cell cycle progression.

p53 negativity, CDC25B positivity, and metallothionein negativity are predictors of a response of esophageal squamous cell carcinoma to chemoradiotherapy

AIM: Esophageal squamous cell carcinoma is generally sensitive to chemoradiotherapy (CRT), but some cases are not. Using a retrospective analysis, we aimed to identify the predictors of the response by esophageal squamous cell carcinoma to definitive CRT.

METHODS: The intensities of expression of p53, Ki67, Bcl-2, Bax, cyclin D1, VEGF, CDC25B, and metallothionein (MT) were evaluated immunohistochemically in the biopsy specimens obtained before CRT, and the intensities of their expression were tested for correlations with the clinical effects of CRT.

RESULTS: The esophageal squamous cell carcinomas with negative p53, positive CDC25B, and negative MT expression were found to be significantly more sensitive to CRT. In addition, p53 positivity and CDC25B positivity respond well to CRT.

CONCLUSION: Esophageal squamous cell carcinomas with negative p53,positive CDC25B, and negative MT expressions respond well to CRT. Even with p53 positivity, if with CDC25B positivity, CRT can be expected.

Prognostic value of multimarker analysis in stage III colorectal cancer: one step forward towards an individualized therapy decision

BACKGROUND

Recently, we have analyzed new prognostic markers in colorectal cancer including neuroendocrine differentiation, overexpression of the sialyl-Lex antigen, overexpression of the peripheral benzodiazepine receptor (PBR), BAX protein expression and p53 mutational status. The predictive power of all markers in combination has not yet been evaluated.

PATIENTS AND METHODS

Between 1989 and 1991, 48 consecutive patients underwent surgery for stage III colorectal cancer at our hospital. All patients received a complete 5-year follow-up. Paraffin-embedded tumor samples were analyzed for all 5 markers. Multivariate discriminant analysis was performed to determine the prognostic value of all markers in combination.

RESULTS

Based on these prognostic markers a mathematical discriminant function was obtained. This function allowed to correctly predict the further course of disease in 77% of the patients (specificity: 83.3%, sensitivity: 70.8%). The discriminant function was confirmed in another group of 19 patients. Single marker analysis allowed the prediction of the further course of disease only in 58-70%.

CONCLUSION

Our study shows that in colorectal cancer, multimarker analysis is superior to unimarker analysis in predicting prognosis. The derived discriminant function allows patient stratification according to risk. Therefore, a multimarker analysis provides a rationale for future individualized risk-adapted therapies in stage III colorectal cancer.

Alterations of Rb Pathway Components Are Frequent Events in Patients with Oral Epithelial Dysplasia and Predict Clinical Outcome in Patients with Squamous Cell Carcinoma

OBJECTIVE

This study was designed to test the hypothesis that alterations in expression of G1/S modulators cyclin D1, p16 and pRb occur in patients with oral epithelial dysplasia, considered to be at increased risk for malignant transformation. In addition, the analysis of expression of all three markers in the same set of oral cancer patients would provide a unique opportunity to determine whether these alterations have cooperative or synergistic effects on oral cancer development and prognosis.

PATIENTS AND METHODS

A prospective study was undertaken to carry out immunohistochemical analysis of cyclin D1, p16 and pRb proteins in serial paraffin-embedded tissue sections of 220 oral squamous cell carcinomas (OSCCs), 90 potentially malignant lesions (52 oral hyperplastic lesions, 38 dysplasias) and 81 matched histologically normal oral tissues and correlated them with clinicopathological parameters. Ninety-eight OSCC patients were followed up for a maximum period of 94 months with overall median survival of 21 months.

RESULTS

Seventy-five of 90 (83%) potentially malignant lesions and 198 of 220 (90%) OSCCs showed altered expression of at least one of the proteins in the pRb pathway, while 10 of 90 (11%) patients with potentially malignant lesions and 40 (18%) of 220 OSCC patients showed all three alterations. Loss of p16 was the earliest event in oral tumorigenesis. In a multivariate model, loss of pRb was associated with transition from hyperplasia to dysplasia (OR = 3.727, p = 0.005). The transition of potentially malignant lesions to malignant stage was associated with pRb-/cyclin D1+ phenotype (OR = 2.294, p = 0.001) and p53+ phenotype (OR = 2.230, p = 0.002). Loss of pRb and accumulation of p53 (pRb-/p53+) phenotype was associated with histologic progression of the tumors and acquisition of invasive potential. Multivariate analysis using Cox's proportional hazards model revealed that pRb-/p53+ phenotype was the most significant adverse prognosticator for disease-free survival (hazards ratio, (HR) = 2.642, p = 0.004).

CONCLUSIONS

Deregulation of the p16/pRb/cyclin D1 pathway is an early event in acquisition of dysplasia, but deregulation of both pRb and p53 pathways is associated with malignant transformation and adverse prognosis in oral tumorigenesis.

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[Basics of molecular diagnostics and therapy of malignant tumors]

Recent insights in disease pathogenesis and mechanisms of resistance to therapy of malignant tumors provide a rational basis for the development of novel therapeutic strategies that target genetic defects and deregulated signaling events in malignant tumors. In contrast to conventional therapeutics, small molecule inhibitors or monoclonal antibodies allow for a far more selective, targeted therapy of tumors that carry a corresponding target structure or gene expression profile. Molecular therapeutics therefore necessitate clinical deployment of genetic diagnostics for the identification of those patients who have a chance to benefit from these novel targeted therapies.

TRAIL sensitizes for ionizing irradiation-induced apoptosis through an entirely Bax-dependent mitochondrial cell death pathway

The death ligand TRAIL has been suggested as a suitable biological agent for the selective induction of cell death in cancer cells. Moreover, TRAIL synergizes with DNA-damaging therapies such as chemotherapeutic drugs or ionizing irradiation (IR). Here, we show that synergy of TRAIL and IR, that is, crosssensitization between TRAIL and IR for induction of apoptosis, entirely depends on Bax proficiency in human DU145 and HCT116 carcinoma cells. DU145 prostate carcinoma cells that have lost Bax protein expression due to mutation fail to activate caspase-3 and -9 when exposed to TRAIL and IR. In contrast, TRAIL sensitized for IR-induced apoptosis and vice versa upon reconstitution of Bax expression. Notably, both DU145 and HCT116 still express significant levels of the multidomain proapoptotic Bcl-2 homolog Bak. This indicates that Bak is not sufficient to mediate crosssensitization and synergism between IR and TRAIL. These data clearly establish distinct roles for Bax and Bak in linking the TRAIL death receptor pathway to the mitochondrial apoptosis signaling cascade upon DNA damage by IR.

Association of cyclin D1, p16 and retinoblastoma protein expressions with prognosis and metastasis of gallbladder carcinoma

AIM: To investigate the role of cyclin D1, p16 and retinoblastoma in cancerous process of gallbladder carcinomas and to assess the relation between cyclin D1, p16, Rb and the biological characteristics of gallbladder carcinoma.

METHODS: Forty-one gallbladder carcinoma, 7 gallbladder adenoma and 14 chronic cholecystitis specimens were immunohistochemically and histopathologically investigated for the relation of cyclin D1, p16 and Rb with Nevin staging and pathologic grading.

RESULTS: The expression rates of abnormal cyclin D1 in gallbladder carcinoma (68.3%)and gallbladder adenoma(57.1%) were significantly higher than those in chronic cholecystitis (7.1%) (P<0.05). No significant difference was found both among the pathological grades G₁, G₂ and G₃ and among Nevin stagings S₁-S₂, S₃ and S₄-S₅ of gallbladder carcinoma. The positive rates of p16 (48.8%) and Rb (58.5%) in gallbladder carcinoma were significantly lower compared to those in adenoma (100.0%) and cholecystitis (100.0%) (P<0.05). The positive rates of p16 and Rb in Nevin stagings S₁-S₂ (80.0% and 90.0%) and S₃ (46.2% and 61.5%) gallbladder carcinomas were significantly higher than those in S₄-S₅ (33.3% and 38.8%) (P<0.05), and those in pathologic grades G₁ (54.5% and 81.8%) and G₂ (50.0% and 62.5%) gallbladder carcinoma were significantly higher than those in G₃ (28.6% and 35.7%) (P<0.05). The protein expression of p16 and Rb had a negative-correlation in gallbladder carcinoma (r = -0.2993, P<0.05), and this negative-correlation was correlated with Nevin staging (P<0.05). Moreover, the protein expression of p16 and cyclin D1 had a negative-correlation in gallbladder carcinoma (r = -0.9417, P<0.05).

CONCLUSION: Cyclin D1 may play a role in the early stage of gallbladder carcinoma. Mutation of p16 and Rb genes might be correlated with progression of gallbladder carcinoma. Analysis of p16 and Rb can estimate the prognosis of gallbladder carcinoma. Expression of p16 and Rb may be correlated with Nevin staging and pathologic grading in gallbladder carcinoma.

Arsenic trioxide triggers a regulated form of caspase-independent necrotic cell death via the mitochondrial death pathway

Cell death is generally believed to occur either by accidental, lytic necrosis or by programmed cell death, that is, apoptosis. The initiation and execution of cell death, however, is far more complex and includes pathways like caspase-independent apoptosis or actively triggered necrosis. In this study, we investigated the mechanisms of cell death induced by arsenic trioxide (arsenite, As2O3), a clinically efficient agent in anticancer therapy. As2O3-induced cell death coincides with cytochrome c release, facilitates mitochondrial permeability transition and is sensitive to inhibition by Bcl-x(L), indicating that cell demise is regulated through the mitochondrial apoptosis pathway. Nevertheless, only little caspase-3 activation was observed and As2O3-induced cell death was only weakly obstructed by the broad spectrum caspase inhibitor z-VAD-fmk. Moreover, disruption of caspase-9 or -2 failed to decrease the amount of As2O3-mediated cell death. Interestingly, As2O3-induced cell death had a predominantly necrosis-like phenotype as assessed by Annexin-V/propidium iodide staining and LDH release. Finally, blocking glutathione synthetase by buthionine sulfoximine enhanced the As2O3-mediated necrosis-like cell death without increasing caspase-3 cleavage. As2O3 does, however, not directly inhibit caspases, but appears to interfere with caspase activation. Altogether, our data clearly delineate a mode of As2O3-triggered cell death that differs considerably from that induced by conventional anticancer drugs. These findings may explain the capability of As2O3 to efficiently kill even chemoresistant tumor cells with disturbed apoptosis signaling and caspase activation, a frequent finding in malignancy.

Multidomain Bcl-2 homolog Bax but not Bak mediates synergistic induction of apoptosis by TRAIL and 5-FU through the mitochondrial apoptosis pathway

The death ligand TRAIL synergizes with DNA-damaging therapies such as chemotherapeutic drugs or ionizing irradiation. Here, we show that the synergism of TRAIL and 5-fluorouracil (5-FU) and cross-sensitization between TRAIL and 5-FU for induction of apoptosis, entirely depend on Bax proficiency in human DU145 and HCT116 carcinoma cells. DU145 prostate carcinoma cells that have lost Bax protein expression due to mutation fail to release cytochrome c and to activate caspase-3 and -9 when exposed to TRAIL and 5-FU. In contrast, TRAIL sensitized for 5-FU-induced apoptosis and vice versa upon reconstitution of Bax expression. Isobolographic analyses of ED50 doses for 5-FU at increasing TRAIL concentrations showed a clear synergism of TRAIL and 5-FU in Bax-expressing cells. In contrast, the effect was merely additive in DU145 cells lacking Bax. Notably, both DU145 and HCT116 Bax-deficient cells still express Bak. This indicates that Bak is not sufficient to mediate cross-sensitization and synergism between 5-FU and TRAIL. Stable overexpression of Bak in DU145 sensitized for epirubicin-induced apoptosis but failed to confer synergy between TRAIL and 5-FU. Moreover, we show by the use of EGFP-tagged Bax and Bak that TRAIL and 5-FU synergistically trigger oligomerization and clustering of Bax but not Bak. These data clearly establish distinct roles for Bax and Bak in linking the TRAIL death receptor pathway to the mitochondrial apoptosis signaling cascade and delineate a higher degree of specificity in signaling for cell death by multidomain Bcl-2 homologs.

Smac induces cytochrome c release and apoptosis independently from Bax/Bcl-x(L) in a strictly caspase-3-dependent manner in human carcinoma cells

The mitochondrial apoptosis pathway mediates cell death through the release of various pro-apoptotic factors including cytochrome c and Smac, the second mitochondrial activator of caspases, into the cytosol. Smac was shown previously to inhibit IAP proteins and to facilitate initiation of the caspase cascade upon cytochrome c release. To investigate Smac function during apoptosis and to explore Smac as an experimental cancer therapeutic, we constructed an expression system based on a single adenoviral vector containing Smac under control of the Tet-off system supplied in cis. Conditional expression of Smac induced apoptosis in human HCT116 and DU145 carcinoma cells regardless of the loss of Bax or overexpression of Bcl-x(L). Nevertheless, apoptosis induced by Smac was associated with cytochrome c release and breakdown of the mitochondrial membrane potential. This indicates that Smac acts independently of Bax and Bcl-x(L) during initiation of apoptosis and triggers a positive feedback loop that results in Bax/Bcl-x(L)-independent activation of mitochondria. In caspase-proficient cells, Smac-induced apoptosis could be inhibited partially by cell-permeable LEHD (caspase-9 inhibitor) and DEVD (caspase-3 inhibitor) peptides. Furthermore, loss of caspase-3 expression in MCF-7 cells carrying a caspase-3 null mutation completely abrogated the sensitivity for Smac-induced apoptotic or nonapoptotic, necrosis-like cell death, while re-expression of caspase-3 conferred sensitivity. Altogether, caspase-3 but not caspase-9 activation was necessary for execution of Smac-induced cell death. Notably, Smac did not induce caspase-9 processing in the absence of caspase-3. Thus, caspase-9 processing occurs secondary to caspase-3 activation during Smac-induced apoptosis. Altogether, Smac is capable of circumventing defects in mitochondrial apoptosis signaling such as loss of Bax or overexpression of Bcl-x(L) that are frequently observed in tumor cells resistant to anticancer therapy. Consequently, Smac appears to be a promising therapeutic target in anticancer treatment.

Loss of p16INK4a expression is associated with vascular endothelial growth factor expression in squamous cell carcinoma of the esophagus

Vascular endothelial growth factor (VEGF) expression has been suggested to correlate with intratumoral microvessel density, tumor advancement and prognosis in esophageal squamous cell carcinoma (ESCC). Previous studies have showed that disruption of cell cycle regulator p16 is related to oncogenesis and tumor progression in ESCC. We hypothesized that VEGF expression in ESCC is reflected by abnormalities in the p16(INK4a) gene. To clarify the regulatory role of p16(INK4a) in VEGF expression in vitro, we transferred the p16(INK4a) gene into a p16(INK4a)-deleted ESCC cell line and observed changes in VEGF expression. Furthermore, we immunohistochemically assessed the expression of the cell cycle regulators (p16, p53 and RB) and VEGF in 90 surgically resected specimens of ESCC. Introduction of p16(INK4a) cDNA by the p16 expression vector significantly suppressed cell proliferation in the p16(INK4a)-deleted cell line TE8 (p < 0.0001). VEGF secretion by TE8 cells transfected with the p16(INK4a) vector was significantly suppressed as compared to non-transfected TE8 cells (p < 0.0001) and TE8 cells transfected with a control vector (p = 0.0015). The immunohistochemical studies of ESCC primary tumor specimens showed that loss of p16 expression was significantly correlated with VEGF-positive expression (p = 0.0004). The cumulative postoperative survival rate in the group with p16-positive and VEGF-negative expression was significantly higher than in the other groups. Neither p53 nor RB expression had any impact on outcome. Aberrant p53 expression tended to be associated with VEGF expression, but the trend did not reach statistical significance. Our study demonstrated that VEGF expression was correlated with p16 expression in ESCC. Our results suggest that p16 may have a regulatory role in VEGF expression in ESCC.

Induction of apoptosis by enediyne antibiotic calicheamicin ϑII proceeds through a caspase-mediated mitochondrial amplification loop in an entirely Bax-dependent manner

Calicheamicin thetaII is a member of the enediyne class of antitumor antibiotics that bind to DNA and induce apoptosis. These compounds differ, however, from conventional anticancer drugs as they bind in a sequence-specific manner noncovalently to DNA and cause sequence-selective oxidation of deoxyriboses and bending of the DNA helix. Calicheamicin is clinically employed as immunoconjugate to antibodies directed against, for example, CD33 in the case of gemtuzumab ozogamicin. Here, we show by the use of the unconjugated drug that calicheamicin-induced apoptosis is independent from death-receptor/FADD-mediated signals. Moreover, calicheamicin triggers apoptosis in a p53-independent manner as shown by the use of p53 knockout cells. Cell death proceeds via activation of mitochondrial permeability transition, cytochrome c release and activation of caspase-9 and -3. The overexpression of Bcl-x(L) or Bcl-2 strongly inhibited calicheamicin-induced apoptosis. Knockout of Bax abrogated cell death after calicheamicin treatment. Thus, the activation of mitochondria and execution of cell death occur through a fully Bax-dependent mechanism. Interestingly, caspase inhibition by the pancaspase-inhibitor zVAD-fmk interfered with mitochondrial activation by calicheamicin. This places caspase activation upstream of the mitochondria and indicates that calicheamicin-triggered apoptosis is enhanced through death receptor-independent activation of the caspase cascade, that is, an amplification loop that is required for full activation of the mitochondrial pathway.

Dynamic expression profile of p21WAF1/CIP1 and Ki-67 predicts survival in rectal carcinoma treated with preoperative radiochemotherapy

PURPOSE

We investigated p53 and its downstream effectors p21WAF1/CIP1, BAX, and hMSH2 as well as the proliferation marker Ki-67 (mki-67/MIB-1) in patients undergoing preoperative radiochemotherapy for rectal carcinoma to identify prognostic and predictive factors. The focus of this study was on the dynamics of these genetic markers in a longitudinal study-that is, before and after radiochemotherapy.

PATIENTS AND METHODS

Expression of p53, BAX, p21WAF1/CIP1, Ki-67, and hMSH2 was investigated by immunohistochemistry in pre- and posttherapeutic tumor samples in 66 patients. Tumor DNA was screened for p53 mutations by single-strand conformation polymorphism-polymerase chain reaction (SSCP-PCR). Paired tumor samples (pretherapy and posttherapy) were collected prospectively.

RESULTS

Patients with a decrease in p21 expression following radiochemotherapy had better disease-free survival (P =.03). Similarly, patients with an increase in proliferative activity as measured by increased Ki-67 expression posttherapy had better disease-free survival (P <.005). In addition, we observed a significantly better prognosis for patients with high hMSH2 expression. In contrast, pretherapeutic levels of p53, BAX, or p21 expression and p53 mutation had no prognostic value, indicating that the combination of radiotherapy and chemotherapy might override defects in these genes.

CONCLUSION

These findings are novel and support the clinical relevance of p21 in the suppression of both proliferation and apoptosis. Thus, the dynamic induction of p21WAF1/CIP1 was associated with a lower proliferative activity but an ultimately worse treatment outcome following neoadjuvant radiochemotherapy and tumor resection. Induction of p21, therefore, represents a novel resistance mechanism in rectal cancer undergoing preoperative radiochemotherapy.

Endoreduplication in conjunction with tumor progression in an aneuploid laryngeal squamous cell carcinoma

We report the case of a 58-year-old man who presented with a squamous cell carcinoma pT1a G2 of the left vocal cord. Six months after histologically verified complete resection, the patient experienced an endolaryngeal and extralaryngeal local recurrence pT4 pN2b G2. We applied DNA flow cytometry (FCM) and comparative genomic hybridization (CGH) on both primary and recurrent tumor. The primary tumor and the endolaryngeal compartment of the relapse was an aneuploid cell clone with a FCM DNA index of 1.42 and 1.44, respectively. The extralaryngeal compartment showed a shift featuring a DNA index of 2.78. In the primary tumor and in both compartments of the recurrence there was an identical pattern of complex chromosomal imbalances as detected in CGH (CGH karyotype: rev ish enh [8q24.2-q24.3, 10q26.1-q26.3, 11q24-q25, 12q24.2-q23.33,X], dim [4q, 13q14.3-q31], amp[1p36.1-p36.2]). Hence, the recurrence was not associated with further gains and losses of chromosomal material. However, in the anterior part of the recurrence, the aneuploid tumor cell genome had completely doubled, obviously due to endoreduplication. Immunohistochemical analysis of several cell-cycle regulators revealed altered expression of checkpoint proteins, pointing to a complex disturbance in cell-cycle regulation.

Mutation of p53 and consecutive selective drug resistance in B-CLL occurs as a consequence of prior DNA-damaging chemotherapy

Inactivation of p53 has been shown to correlate with poor prognosis and drug resistance in malignant tumors. Nevertheless, few reports have directly shown such effects in primary tumor cells. Here, we investigated the p53 mutational status in 138 B-CLL samples and compared these findings with drug and gamma-irradiation sensitivity profiles. p53 mutations resulted not only in a shorter survival but, notably also in selective resistance to alkylating agents, fludarabine and gamma-irradiation. In contrast, no such effect was observed for vincristine, anthracyclines and glucocorticoids. Thus, these latter compounds induce cell death at least in part by p53-independent pathways. Interestingly, p53 mutations clustered in patients who had received prior chemotherapy. In fact, we show for the first time that treatment with DNA-damaging alkylating agents correlates with occurrence of p53 mutations in a clinical setting. This finding may explain at least to some extent the development of resistance to second-line anticancer chemotherapy.