Apoptosis and cell-cycle regulatory proteins in colorectal carcinoma: relationship to tumour stage and patient survival

Pharmacological iron-chelation as an assisted nutritional immunity strategy against Piscirickettsia salmonis infection

Salmonid Rickettsial Septicaemia (SRS), caused by Piscirickettsia salmonis, is a severe bacterial disease in the Chilean salmon farming industry. Vaccines and antibiotics are the current strategies to fight SRS; however, the high frequency of new epizootic events confirms the need to develop new strategies to combat this disease. An innovative opportunity is perturbing the host pathways used by the microorganisms to replicate inside host cells through host-directed antimicrobial drugs (HDAD). Iron is a critical nutrient for P. salmonis infection; hence, the use of iron-chelators becomes an excellent alternative to be used as HDAD. The aim of this work was to use the iron chelator Deferiprone (DFP) as HDAD to treat SRS. Here, we describe the protective effect of the iron chelator DFP over P. salmonis infections at non-antibiotic concentrations, in bacterial challenges both in vitro and in vivo. At the cellular level, our results indicate that DFP reduced the intracellular iron content by 33.1% and P. salmonis relative load during bacterial infections by 78%. These findings were recapitulated in fish, where DFP reduced the mortality of rainbow trout challenged with P. salmonis in 34.9% compared to the non-treated group. This is the first report of the protective capacity of an iron chelator against infection in fish, becoming a potential effective host-directed therapy for SRS and other animals against ferrophilic pathogens.

Apoptosis as a Prognostic Factor in Colorectal Carcinoma: Comparison of TUNEL Method and Immunohistochemical Expression of Caspase-3

The development of colorectal cancer is known to be characterized by a sequence of events during which normal colonic epithelium gradually transforms to carcinoma, the adenoma-carcinoma sequence. Apoptosis plays an important role in the development and maintenance of tissue homeostasis. Currently, there is no agreement in the literature about the prognosis of apoptosis in colorectal cancer. The number of studies examining the expression of caspases in colorectal cancer is very limited, and they have not examined any correlation between expression and patient survival. This study included histologic samples from 179 patients diagnosed with colon cancer. We used the TdT-mediated X-dUTP nick end labeling method and caspase-3 labeling to identify the degree of apoptosis. Our results show that lower apoptotic index measured by TdT-mediated X-dUTP nick end labeling method and lower immnuhistochemical expression of caspase-3 is associated with shorter disease-free survival and overall survival. However, only apoptotic index is proven to be an independent survival indicator. The results of our study are consistent with the proposed models of carcinogenesis of colorectal cancer that emphasize resistance to apoptosis as a decisive factor in the progression of the disease and resistance to treatment.

High expression of anti-apoptotic protein Bcl-2 is a good prognostic factor in colorectal cancer: Result of a meta-analysis

AIM

To systematically evaluate the prognostic-predictive capability of Bcl-2 in colorectal cancer (CRC).

METHODS

A systematic literature search was conducted using PubMed, Web of Science and EMBASE databases. Any eligible study must meet the following criteria: (1) bcl-2 expression was evaluated in human CRC tissues by immunohistochemistry; (2) assessment of the relationships between bcl-2 expression and overall survival (OS), disease free survival (DFS), recurrent free survival (RFS) or clinic-pathological characteristics of CRC was included; (3) sufficient information was provided to estimate the hazard ratio (HR) or odds ratio and their 95% confidence intervals (CIs); and (4) the study was published in English. The impact of Bcl-2 expression on survival of CRC patients were evaluated through this meta-analysis.

RESULTS

A total of 40 eligible articles involving 7658 patients were enrolled in our final analysis. We drew the conclusion that Bcl-2 high expression was significantly correlated with favorable OS (pooled HR = 0.69, 95%CI: 0.55-0.87, P = 0.002) and better DFS/RFS (pooled HR = 0.65, 95%CI: 0.50-0.85, P = 0.001). Additionally, the subgroup analysis suggested that Bcl-2 overexpression was significantly associated with prognosis (OS) especially in patients came from Europe and America but not Asian and patients who did not receive any adjuvant therapy before surgery. Finally, our present results indicated that expression of bcl-2 protein was associated with high differentiation grade and A/B Ducks’ stage.

CONCLUSION

Bcl-2 high expression was significantly correlated with favorable OS and better DFS/RFS. Hence, we propose that Bcl-2 may be a valuable prognostic-predictive marker in CRC.

High quality tissue miniarray technique using a conventional TV/radio telescopic antenna

BACKGROUND

The tissue microarray (TMA) is widely accepted as a fast and cost-effective research tool for in situ tissue analysis in modern pathology. However, the current automated and manual TMA techniques have some drawbacks restricting their productivity. Our study aimed to introduce an improved manual tissue miniarray (TmA) technique that is simple and readily applicable to a broad range of tissue samples.

MATERIALS AND METHODS

In this study, a conventional TV/radio telescopic antenna was used to punch tissue cores manually from donor paraffin embedded tissue blocks which were pre-incubated at 40oC. The cores were manually transferred, organized and attached to a standard block mould, and filled with liquid paraffin to construct TmA blocks without any use of recipient paraffin blocks.

RESULTS

By using a conventional TV/radio antenna, it was possible to construct TmA paraffin blocks with variable formats of array size and number (2-mm x 42, 2.5-mm x 30, 3-mm x 24, 4-mm x 20 and 5-mm x 12 cores). Up to 2-mm x 84 cores could be mounted and stained on a standard microscopic slide by cutting two sections from two different blocks and mounting them beside each other. The technique was simple and caused minimal damage to the donor blocks. H and E and immunostained slides showed well-defined tissue morphology and array configuration.

CONCLUSIONS

This technique is easy to reproduce, quick, inexpensive and creates uniform blocks with abundant tissues without specialized equipment. It was found to improve the stability of the cores within the paraffin block and facilitated no losses during cutting and immunostaining.

Hesperidin induces apoptosis and triggers autophagic markers through inhibition of Aurora-A mediated phosphoinositide-3-kinase/Akt/mammalian target of rapamycin and glycogen synthase kinase-3 beta signalling cascades in experimental colon carcinogenesis

Abnormalities in the homeostasis mechanisms involved in cell survival and apoptosis are contributing factors for colon carcinogenesis. Interventions of these mechanisms by pharmacologically safer agents gain predominance in colon cancer prevention. We previously reported the chemopreventive efficacy of hesperidin against colon carcinogenesis. In the present study, we aimed at investigating the potential of hesperidin over the abrogated Aurora-A coupled pro-survival phosphoinositide-3-kinase (PI3K)/Akt signalling cascades. Further, the role of hesperidin over apoptosis and mammalian target of rapamycin (mTOR) mediated autophagic responses were studied. Azoxymethane (AOM) induced mouse model of colon carcinogenesis was involved in this study. Hesperidin treatment was provided either in initiation/post-initiation mode respectively. Hesperidin significantly altered AOM mediated anti-apoptotic scenario by modulating Bax/Bcl-2 ratio together with enhanced cytochrome-c release and caspase-3, 9 activations. In addition, hesperidin enhanced p53-p21 axis with concomitant decrease in cell cycle regulator. Hesperidin treatment caused significant up-regulation of tumour suppressor phosphatase and tensin homologue (PTEN) with a reduction in the expression of AOM mediated p-PI3K and p-Akt. Additionally, hesperidin administration exhibited inhibition against p-mTOR expression which in turn led to stimulation of autophagic markers Beclin-1 and LC3-II. Aurora-A an upstream regulator of PI3K/Akt pathway was significantly inhibited by hesperidin. Furthermore, hesperidin administration restored glycogen synthase kinase-3 beta (GSK-3β) activity which in turn prevented the accumulation of oncoproteins β-catenin, c-jun and c-myc. Taken together, hesperidin supplementation initiated apoptosis via targeted inhibition of constitutively activated Aurora-A mediated PI3K/Akt/GSK-3β and mTOR pathways coupled with autophagic stimulation against AOM induced colon carcinogenesis.

Capsaicin mediates cell cycle arrest and apoptosis in human colon cancer cells via stabilizing and activating p53

Capsaicin is the major pungent ingredient in red peppers which is world widely consumed. Except its potent pain relieving efficacy as reported, capsaicin also exerted its antitumor activity in several tumor models. Here, we reported that capsaicin had a profound anti-proliferative effect on human colon cancer cells via inducing cell cycle G0/G1 phase arrest and apoptosis, which was associated with an increase of p21, Bax and cleaved PARP. The underlying mechanism of capsaicin's antitumor potency was mainly attributed to the stabilization and activation of p53. Capsaicin substantially prolonged the half-life of p53 and significantly elevated the transcriptional activity of p53. Through suppressing the interaction between p53 and MDM2, MDM2-mediated p53 ubiquitination was remarkably decreased after capsaicin treatment, which resulted in the stabilization and accumulation of p53. The results of p53-shRNA experiment further demonstrated that p53 knockdown severely impaired the sensitivity of tested cells to capsaicin, G0/G1 phase arrest and the apoptosis induced by capsaicin in p53-knockdown cells was also dramatically decreased, implicating the important role of p53 played in capsaicin's antitumor activity. In summary, our data suggested that capsaicin, or a related analogue, may have a role in the management of human colon cancer.

The role and prognostic value of apoptosis in colorectal carcinoma

Background

Alterations to apoptosis are a common occurrence in human tumours. The aim of our study was to determine the influence of apoptotic variations on the carcinogenesis and prognosis of colorectal carcinomas (CRCs).

Methods

A TUNEL assay was performed on archival material from 103 colorectal carcinomas, 26 adenomas and 20 samples of normal epithelia.

Results

The number of apoptotic cells was higher in CRCs (1.09 ± 0.13) than in adenomas (0.38 ± 0.23, p = 0.059) and normal epithelium (0.06 ± 0.04, p = 0.001). In addition, the apoptotic index (AI) was greater in metastatic disease (stage IV) than in other stages (p = 0.017). No relationship was found between apoptotic rates and age, gender or tumour grade. However, patients with tumours that showed higher AI values had a significantly lower disease-free survival (DFS) and overall survival (OS) than those with tumours that had lower AIs (p = 0.020 and p = 0.027). In a multivariate Cox proportional hazards model, AI remained a significant independent predictor of survival.

Conclusions

We conclude that disregulated apoptosis is an important event during CRC development and progression. Higher AIs are associated with more aggressive tumours and a poorer prognosis for patients with CRC.

The prognostic value of the apoptosis pathway in colorectal cancer: a review of the literature on biomarkers identified by immunohistochemistry

Research towards biomarkers that predict patient outcome in colorectal cancer (CRC) is rapidly expanding. However, none of these biomarkers have been recommended by the American Association of Clinical Oncology or the European Group on Tumor Markers. Current staging criteria result in substantial under-and over-treatment of CRC patients. Evasion of apoptosis, a characteristic feature of tumorigenesis, is known to correlate with patient outcome. We reviewed the literature on immunohistochemistry-based studies between 1998 and 2011 describing biomarkers in this pathway in CRC and identified 26 markers. Most frequently described were p53, Bcl-2, survivin, and the Fas and TRAILR1 receptors and their ligands. None of the studies reviewed provided sufficient support for implementing a single marker into current clinical practice. This is likely due to the complex biology of this pathway. We suggest focusing on the combination of key markers within the apoptosis pathway that together represent an ‘apoptotic tumor profile’, which better reflects the status of this pathway in a tumor.

Cell cycle proteins predict recurrence in stage II and III colon cancer

PURPOSE

To investigate the prognostic value of multiple cell cycle-associated proteins in a large series of stage II and III colon cancers.

METHODS

From formalin-fixed, paraffin-embedded tumor samples of 386 patients with stage II and III colon cancer, DNA was isolated and tissue microarrays were constructed. Tissue microarray slides were immunohistochemically stained for p21, p27, p53, epidermal growth factor receptor, Her2/Neu, β-catenin, cyclin D1, Ki-67, thymidylate synthase, and Aurora kinase A (AURKA). Polymerase chain reaction-based microsatellite instability analysis was performed to allow for stratification of protein expression by microsatellite instability status.

RESULTS

Overall, low p21, high p53, low cyclin D1, and high AURKA expression were significantly associated with recurrence (P = 0.01, P < 0.01, P = 0.04, and P < 0.01, respectively). In stage II patients who did not receive adjuvant chemotherapy (n = 190), significantly more recurrences were observed in case of low-p21 and high-p53-expressing tumors (P < 0.01 and P = 0.03, respectively). In stage III patients who did not receive chemotherapy, high p53 expression was associated with recurrence (P = 0.02), and in patients who received chemotherapy, high AURKA expression was associated with relapse (P < 0.01). In patients with microsatellite stable tumors, high levels of p53 and AURKA were associated with recurrence (P = 0.01 and P < 0.01, respectively). Multivariate analysis showed p21 (odds ratio 1.6, 95% confidence interval 0.9-2.8) and AURKA (odds ratio 2.7, 95% confidence interval 1.3-5.6) to be independently associated with disease recurrence.

CONCLUSIONS

p21, p53, cyclin D1, and AURKA could possibly be used as prognostic markers to identify colon cancer patients with high risk of disease recurrence.

Serum biomarkers of cell death for monitoring therapy response of gastrointestinal carcinomas

PURPOSE

Antitumour treatments are thought to exert their therapeutic efficacy mainly by induction of apoptosis in tumour cells. In epithelial cells, caspases, the key enzymes of apoptosis, cleave the intermediate filament protein cytokeratin (CK)-18 into specific fragments that are released into circulating blood and can be detected by a specific ELISA.

EXPERIMENTAL DESIGN

To investigate the use of CK-18 fragments as a potential biomarker for the treatment response, we examined the association of serum CK-18 levels and clinical response in 35 patients with gastrointestinal cancers.

RESULTS

While both cleaved and total CK-18 levels were intrinsically elevated in tumour patients, they were further increased during 5-fluorouracil (5-FU)-based therapy. Importantly, the increased levels of CK-18 could discriminate between patients with different clinical response. Cancer patients with a partial response or stable disease revealed a significantly higher increase of cleaved CK-18 during chemotherapy as compared to patients with progressive disease.

CONCLUSIONS

Our results suggest that detection of circulating caspase-cleaved CK-18 might be a useful serum biomarker for monitoring treatment response and should merit further evaluation in larger patient groups.

p21 expression in colon cancer and modifying effects of patient age and body mass index on prognosis

p21 (Cyclin-dependent kinase inhibitor-1A, CDKN1A or CIP1) plays a role in regulating cell cycle, and its expression is lost in most colorectal cancers. p21 Is related with energy balance status, cellular senescence, and stem cell aging. Thus, the influence of p21 loss on tumor behavior and clinical outcome may be modified by patient age and body mass index (BMI). Using 647 colon cancers in two independent prospective cohorts, p21 loss was observed in 509 (79%) tumors by immunohistochemistry. Cox proportional hazard models computed hazard ratio (HR) for death, adjusted for potential confounders, including p53, cyclin D1, KRAS, BRAF, PIK3CA, LINE-1 hypomethylation, CpG island methylator phenotype (CIMP), and microsatellite instability (MSI). p21 Loss was independently associated with low colon cancer-specific mortality [HR, 0.58; 95% confidence interval (95% CI), 0.38-0.89; adjusted for the covariates including MSI, CIMP, and LINE-1 methylation]. The prognostic effect of p21 loss differed significantly by age at diagnosis (P(interaction) < 0.0001) and BMI (P(interaction) = 0.002). The adjusted HR for cancer-specific mortality (p21 loss versus p21 expression) was 4.09 (95% CI, 1.13-14.9) among patients <60 year old and 0.37 (95% CI, 0.24-0.59) among patients >or=60 year old. The adverse prognostic effect of obesity was limited to p21-expressing cases (adjusted HR, 5.85; 95% CI, 2.28-15.0; BMI, >or=30 versus <30 kg/m(2)), but no such effect was observed among p21-lost cases. In conclusion, p21 loss in colon cancer is associated with longer survival among patients >or=60 year old, whereas it is associated with shorter survival among patients <60 year old. Patient BMI also differentially influences prognosis according to p21 CDKN1A status. Our data suggest host-tumor interactions influencing tumor aggressiveness.

P53 Arg72Pro polymorphism in gastric cancer patients

INTRODUCTION

Polymorphism in codon 72, exon 4 of p53 may alter apoptosis and cancer progression.

PATIENTS AND METHODS

P53 Arg72Pro genotype was assessed by PCR from 84 gastric cancer patients and 185 controls. The control group was comparable in sex, race, age, smoking, and alcohol intake to the cancer group.

RESULTS AND DISCUSSION

There was no difference among the frequency of the alleles or genotypes between the groups. P53 Pro/Pro was associated to a lower risk of metastatic disease (p = 0.02) but not to lymph nodes metastasis or worst prognosis. Arg/Arg or Arg/Pro genotype may be associated to metastatic disease.

Potential role of apoptosis and apoptotic regulatory proteins in colorectal neoplasia: correlations with clinico-pathological parameters and survival

An imbalance between apoptotic and proliferative processes is believed to underlie colorectal neoplasia. We evaluated the expression of bcl-2, p53, mdm2 proteins, and apoptosis in colorectal neoplasms, as well as their correlation with clinico-pathological parameters, using image analysis. Biopsies from 46 colorectal cancers, 121 adenomas, and 25 controls were studied using monoclonal antibodies against p53, bcl-2, mdm2 and the terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling (TUNEL) method for apoptosis. P53 and bcl2 protein expression was higher in adenomas >or=1 cm (P < 0.03) and tubulovillous-villous adenomas (P < 0.03), and correlated with dysplasia (P < 0.03). In Cox regression analysis, Dukes' stage was the most significant independent prognostic indicator of a worse survival (P < 0.019), whereas when stage was eliminated, bcl-2 expression was also a powerful predictor for bad prognosis (P = 0.02). In conclusion, both bcl-2 and p53 immunohistochemical profiles may be useful adjuncts in detecting adenomas with a malignant potential, whereas bcl-2 could be used in combination with Dukes' stage as a predictor of prognosis in colorectal cancer.

Prognostic value of apoptosis in rectal cancer patients of the dutch total mesorectal excision trial: radiotherapy is redundant in intrinsically high-apoptotic tumors

PURPOSE

The combination of radiotherapy and good quality surgery reduces local recurrence rate for rectal cancer patients. This study assesses the prognostic value of both intrinsic and radiotherapy-induced apoptosis and evaluates the relevance of radiotherapy for outcome of rectal cancer patients.

EXPERIMENTAL DESIGN

Tumor samples (1,198) were available from the Dutch Total Mesorectal Excision trial, in which rectal cancer patients were treated with standardized surgery and randomized for preoperative short-term radiotherapy or not. Tumor samples were obtained at time of surgery. Tissue microarrays were constructed and stained with the active caspase-specific M30 antibody to determine the amount of apoptotic epithelial tumor cells.

RESULTS

Nonirradiated patients with a negative circumferential margin displaying lower than median levels of apoptosis developed more local recurrences (10.5% versus 6.1%; P=0.06) and more rapidly after surgery than patients with high intrinsic apoptosis in their tumors (median time to recurrence, 13.0 versus 21.3 months; P=0.04). In multivariate analysis, intrinsic apoptosis was an independent predictor for the development of local recurrences (hazard ratio, 2.0; P=0.05). Radiotherapy increased apoptosis level (11 versus 23 apoptotic cells/mm2 tumor epithelium; P<0.001), but this apoptosis did not influence patients' prognosis.

CONCLUSIONS

Rectal cancer patients with low intrinsic apoptosis will benefit from radiotherapy with respect to the development of local recurrences. Because apoptosis is an inherent characteristic of tumors, patients who do not need radiotherapy may be selected based on the apoptotic index of the primary tumor.

The significance of tumor markers for proliferation and apoptosis in predicting survival in colorectal cancer

PURPOSE

Clinicopathologic staging is even today the best prognostic factor in both colon and rectal cancers. There is still considerable variation in survival within the stages. To find other prognostic indicators we investigated six biologic markers associated with apoptosis and cell proliferation.

METHODS

Formalin-fixed, paraffin-embedded tissue samples of 363 patients with primary colon or rectal cancer of Dukes Stages A to D were chosen for immunohistochemical staining of five tumor markers: bcl-2, p53, Ki-67, cyclin D1, and carcinoembryonic antigen. Also, the number of apoptotic cells was studied by the terminal deoxynucleotidyl transferase-mediated D: -UTP nick end labeling method in 347 cases. The study was done on specially prepared tissue arrays.

RESULTS

In rectal cancer, patients with a Ki-67 labeling index of 5 percent or higher had a better prognosis than those with a lower index. Also, positive cytoplasmic p53 expression predicted a favorable outcome in rectal cancer. In colon cancer, positive nuclear staining of cyclin D1 reflected better survival. Weak and moderate staining of carcinoembryonic antigen correlated with better prognosis than strong staining, but negative staining predicted poor outcome. High apoptotic index of 100 or higher correlated with poor prognosis in colon cancer. However, in rectal cancer, the trend was the opposite. Bcl-2 staining tended to be more intense in samples of patients living 5 years or longer compared with those with worse prognosis.

CONCLUSIONS

Colon cancer and rectal cancer seem to have different biologic behavior, at least with respect to apoptosis, cytoplasmic p53 expression, and perhaps Ki-67 and carcinoembryonic antigen. Further studies are needed to clarify the significance of these factors.

Evidence that the p53 negative / Bcl-2 positive phenotype is an independent indicator of good prognosis in colorectal cancer: a tissue microarray study of 460 patients

BACKGROUND

Advances in our understanding of the molecular biology of colorectal cancer have fuelled the search for novel molecular prognostic markers to complement existing staging systems. Markers assessed in combination may perform better than those considered individually. Using high-throughput tissue microarray technology, we describe the prognostic value of combined p53 / Bcl-2 status in colorectal cancer.

PATIENTS AND METHODS

Tumour samples from 462 patients who underwent elective surgery to resect a primary colorectal cancer between 1994 and 2000 (mean follow-up of 75 months) were assembled in tissue microarray format. Clinico-pathological data including tumour grade, stage, vascular invasion status along with disease specific survival data has been collected prospectively. Immunohistochemical analysis of p53 and Bcl-2 expression was performed using antibodies DO-7 (p53) and 124 (Bcl-2), and results correlated with known clinico-pathological variables and outcomes.

RESULTS

Abnormal nuclear p53 accumulation and Bcl-2 overexpression were detected in 221/445 (49.6%) and199/437 (45.5%) tumours respectively, with a significant inverse correlation between the two markers (p = 0.023). On univariate analysis no correlations were found between either marker and standard clinico-pathological variables, however nuclear p53 expression was associated with a significantly reduced survival (p = 0.024). Combined analysis of the two markers indicated that 112/432 (24.2%) cases displayed a p53(-)/Bcl-2(+) phenotype, this occurring more frequently in earlier stage tumours. Kaplan-Meier analysis revealed a significant survival advantage in these p53(-)/Bcl-2(+) tumours compared with the remaining cases (p = 0.0032). On multivariate analysis using the Cox proportional hazards model, neither p53 expression nor Bcl-2 expression alone were of independent prognostic significance, however the combined p53(-)/Bcl-2(+) phenotype was significantly associated with a good prognosis in this series (HR 0.659, 95%CI 0.452-0.959, p = 0.029).

CONCLUSION

Patient stratification by combined p53 / Bcl-2 phenotype provides stage-independent prognostic information in colorectal cancer. Specifically, that up to a quarter of patients display a good prognosis p53(-)/Bcl-2(+) phenotype. This may indicate a more clinically indolent phenotype and a subset of patients for whom less aggressive adjuvant treatment appropriate.

P21Cip1 is a critical mediator of the cytotoxic action of thymidylate synthase inhibitors in colorectal carcinoma cells

We have demonstrated previously that interferon (IFN)-gamma sensitizes human colon carcinoma cell lines to the cytotoxic effects of 5-fluorouracil combined with leucovorin and to the thymidylate synthase inhibitor, ZD9331, dependent on thymineless stress-induced DNA damage, independent of p53. Here we demonstrate that the cyclin-dependent kinase (CDK) inhibitor p21(Cip1) regulates thymineless stress-induced cytotoxicity in these cells. HCT116 wild-type (wt) and p53-/- cells underwent apoptosis and loss in clonogenic survival when exposed to ZD9331, whereas p21Cip1-/- cells were resistant. In contrast, IFN-gamma induced marked cytotoxicity in p21Cip1-/- cells only. ZD9331 induced p21Cip1 up-regulation in all of the cell lines examined, as did thymidine deprivation in thymidylate synthase-deficient (thymidylate synthase-) cells. Furthermore, selective induction of p21Cip1 in RKO was sufficient to induce apoptosis. P21Cip1, cdk1, cdk2, and cyclin E mRNA expression increased coincident with S-phase accumulation in HT29 cells treated with ZD9331 or 5fluorouracil/leucovorin, as demonstrated by cDNA microarray analyses. Cell cycle analyses revealed that HCT116 wt and p21Cip1 -/- cells accumulated in S phase within 24 h of ZD9331 exposure; however, wt cells exited S-phase more rapidly, where apoptosis occurred before mitosis, either in late S or G2. Finally, the CDK inhibitor roscovitine potentiated the cytotoxic activity of ZD9331 in both wt and p21Cip1-/- cells, strongly suggesting a role for p21Cip1-dependent CDK inhibition in cytotoxicity induced by thymidylate synthase inhibition. In summary, p21Cip1 positively regulates the cytotoxic action of thymidylate synthase inhibitors, negatively regulates the cytotoxic action of IFN-gamma, and enhances S-phase exit after thymineless stress, possibly via interaction with CDK-cyclin complexes.

Prognostic value of apoptosis and apoptosis-associated proteins in salivary gland adenoid cystic carcinoma

The purpose of the present study was to investigate the level of apoptosis and expressions of p53, mdm2 and bcl-2 proteins in salivary gland adenoid cystic carcinoma (ACC) to determine potential relationships among apoptosis, apoptosis-associated proteins and clinical cumulative survival. Thirty-nine formalin-fixed, paraffin-embedded cases, cribriform (17), tubular (13) and solid (9), were studied by immunohistochemistry. Apoptosis detection and analysis were determined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL). There was an inverse significance between the apoptotic index (AI) and bcl-2 expression (P = 0.018), whereas no correlation was found between the AI and either p53 or mdm2 expression (P = 0.416 and P = 0.456). Co-expression of p53 and mdm2 was found in 22 cases (P = 0.037). Patients with p53-positive tumors had a worse prognosis than those with p53-negative tumors (P = 0.014). Patients with a high AI had a better cumulative survival than patients with a low AI (P = 0.038). The present study suggests that p53 expression and AI can be useful as prognostic values; bcl-2 protein plays a role in the down-regulation of apoptosis and is also potentially useful as a prognostic parameter in salivary gland ACC.

p53 Alterations and Their Relationship to SDHD Mutations in Parasympathetic Paragangliomas

Experimental and observational evidence suggests that chronic hypoxic stimulation can induce parasympathetic paraganglioma. This is emphasized by the identification of germline mutations in genes of the mitochondrial succinate dehydrogenase enzyme complex II in hereditary paraganglioma. Because of inactivating mutations in the succinate dehydrogenase subunit B (SDHB), C (SDHC), or D (SDHD) gene, the paraganglia undergo a chronic hypoxic stimulus leading to proliferation of the paraganglionic cells. Hypoxia is a known inducer of p53 up-regulation, which triggers cell cycle arrest and apoptosis. Inactivation of the p53 pathway, by gene mutation or by MDM2 overexpression, would enable cells to escape from cell cycle arrest and apoptosis and could contribute to tumorigenesis. To determine whether p53 inactivation plays a role in paraganglioma tumorigenesis, we investigated a series of 43 paragangliomas from 41 patients (of whom 24 patients harbored a germline SDHD mutation) for mutations in p53 exons 5-8 by PCR-SSCP. In addition, these tumors were investigated for p53 and MDM2 protein expression by immunohistochemistry, and the results were compared with clinical data and the presence of SDHD mutations. No aberrations in p53 exons 5-8 were found. The immunohistochemical experiments showed nuclear p53 expression in 15 tumors. Three tumors were positive for MDM2 that were also positive for p53. There was no correlation between p53 and MDM2 expression and clinical data or SDHD status. Given the fact that hypoxia induces p53 expression and regarding the absence of p53 mutations, these results suggest that p53 inactivation does not play a major role in the tumorigenesis of hereditary and sporadic paragangliomas.

The prognostic relevance of apoptosis-related proteins in classical Hodgkin's lymphomas

Neoplastic cells in classical Hodgkin's lymphomas (cHL) seem to correspond to defective germinal center B-cells, which escape from apoptosis. Epstein-Barr virus (EBV) may be implicated in this protective mechanism. The aim of the present study was to determine the expression of apoptosis-related proteins in cHL among adult patients and correlate them with EBV expression, clinical findings and survival. EBV was detected by in situ hybridization (Epstein-Barr Encoded RNA, EBER, probe). Immunohistochemistry was used on paraffin sections to detect LMP-1/EBV, CD15 and the apoptosis-related proteins (bcl-2, bax, bcl-X, mcl-1 and CD95). Seventy-eight patients seen at our Institution were studied: 36 male and 42 female. Median age was 31 years (15-75 years). Histological types of cHL were: 61 nodular sclerosis (47 NS1 and 14 NS2), 15 mixed cellularity (MC), 1 lymphocyte depletion and 1 unclassified. In 50 cases there was EBV expression (64%). At least one apoptosis-associated protein was expressed in 92% and CD15 in 57.7% of the cases. In the univariate analysis, the following variables were related to a better overall survival: expression of CD15 (p = 0.023), expression of mcl-1 protein (p = 0.029), expression of bcl-2 protein (p = 0.028, only in a Cox model after stratification for histology) and expression of LMP-1 (p = 0.042). EBV expression presented a borderline inverse correlation with bcl-2. A prognostic index (PI) developed in the present study revealed that simultaneous expression of bcl-2, mcl-1 and LMP-1 was significant and independently correlated with an excellent survival.

Prognostic significance of calcium-binding protein S100A4 in colorectal cancer

BACKGROUND & AIMS

Prognostication in colon cancer almost exclusively still rests on the tumor stage. Furthermore, tumor-derived markers to improve discrimination of low- and high-risk subtypes generally are not in use. S100A4 has been reported to be associated with invasion and metastasis; however, no data are available on its prognostic value in colorectal carcinoma. Therefore, we investigated the prognostic significance of immunohistochemical S100A4 expression in colorectal carcinoma compared with clinicopathologic parameters and expression of cell-cycle markers p16, p21, p27, p53, Ki-67, and RB.

METHODS

Archival tissue from 709 patients with colorectal cancer were retrieved, applied in tissue array technology, and investigated immunohistochemically. Univariate and multivariate survival analyses were carried out on all investigated parameters.

RESULTS

Sixteen percent of cases showed high; 31%, low; and 53%, no S100A4 expression. In Kaplan-Meier analysis, S100A4 positively stained cases showed a significantly decreased survival time compared with negatively stained cases (P < 0.0001). In multivariate regression analysis, S100A4 expression emerged as a highly significant independent parameter (P < 0.001) with the highest relative-risk factor among other covariates. Nodal status (pN) lost its prognostic value if S100A4 was added to the model. High S100A4 expression was associated with tumor stage pT3/4, secondary metastasis, women, p16, and RB expression.

CONCLUSIONS

S100A4 expression represents a highly significant prognostic marker in colorectal carcinoma, which is able to identify a subset of patients at high risk. In this respect, it is superior to established prognostic markers such as nodal status, pT stage, and p53 expression.