Bcl-2 expression is correlated with low apoptotic index and associated with histopathological grading in esophageal squamous cell carcinomas

Obatoclax induces G1/G0-phase arrest via p38/p21(waf1/Cip1) signaling pathway in human esophageal cancer cells

Pan-Bcl-2 family inhibitor obatoclax has been demonstrated to be effective against various cancers, of which the mechanism of action is not fully understood. In this study, we demonstrate that obatoclax suppressed esophageal cancer cell viability with concomitant G1/G0-phase cell cycle arrest. At the tested concentrations (1/2 IC50 and IC50), obatoclax neither induced PARP cleavage nor increased the Annexin V-positive population, suggesting G1/G0-phase arrest rather than apoptosis accounts for most of the reduction of cell viability produced by obatoclax. Double knockdown of Bak and Bax by small interference RNA failed to block obatoclax-induced G1/G0-phase arrest, implying its role in cell cycle progression is Bak/Bax-independent. The cell cycle arresting effect of obatoclax was associated with up-regulation of p21(waf1/Cip1). Knockdown of p21(waf1/Cip1) significantly attenuated obatoclax-induced G1/G0-phase arrest. Although obatoclax stimulated phosphorylation of Erk, p38, and JNK, pharmacological inhibition of p38 but not Erk or JNK blocked obatoclax-induced G1/G0-phase arrest. Moreover, knockdown of p38 abolished the cell cycle arresting effect of obatoclax. In consistent with this finding, inhibition of p38 blocked obatoclax-induced p21(waf1/Cip1) expression while inhibition of Erk or JNK failed to exert similar effect. To conclude, these findings suggest that obatoclax induced cell cycle arrest via p38/p21(waf1/Cip1) signaling pathway. This study may shed a new light on the anti-cancer activity of obatoclax in relation to cell cycle arrest.

Effect of omeprazole dose, nonsteroidal anti-inflammatory agents, and smoking on repair mechanisms in acute peptic ulcer bleeding

BACKGROUND

Peptic ulcer bleeding (PUB) is a major cause of upper gastrointestinal bleeding. The effect of omeprazole on mucosal repair is unknown.

AIMS

We studied the effect of omeprazole, nonsteroidal anti-inflammatory agents, and smoking on PUB.

METHODS

There were 43 PUB patients who received regular or high dose of omeprazole for 72 h. Biopsies from antrum and corpus were taken before and after treatment. Biopsy samples from 20 celiac disease patients worked as controls. The expression of Ki-67, Bcl-2, COX-2, Hsp27, and Hsp70 was analyzed from patients and controls.

RESULTS

Bcl-2 expression in PUB patients was lower than in controls. However, Bcl-2 increased significantly from 5.0 (SD 4.5) to 9.1 % (SD 6.7), p = 0.0004, in the antrum after omeprazole. In univariate analysis, a high omeprazole dose caused a more profound increase in Ki-67 expression in the corpus: 35.3 % (SD 54.8) than a regular dose: -10.1 % (SD 40.6), p = 0.022. In multivariate analysis, Ki-67 decreased significantly in the corpus between the pre- and posttreatment period (p = 0.011), while a high omeprazole dose (p = 0.0265), the use of NSAIDs (p = 0.0208), and smoking (p = 0.0296) significantly increased Ki-67 expression. Bcl-2 in the corpus increased significantly (p = 0.0003) after treatment.

CONCLUSIONS

Our findings suggest that Bcl-2 may be an important factor in the pathogenesis of a peptic ulcer and PUB. In addition, high-dose omeprazole increased the expression of Ki-67, which may enhance the healing process of a peptic ulcer.

Autophagy contributes to modulating the cytotoxicities of Bcl-2 homology domain-3 mimetics

The dysregulation of apoptosis is a key step in developing cancers, and mediates resistance to cancer therapy. Commitment to apoptosis is caused by permeabilization of the outer mitochondrial membrane, a process regulated by the interactions between different proteins of Bcl-2 family. Furthermore, Bcl-2 family proteins also bind to the endoplasmic reticulum, where they modulate autophagy, another important pathway regulating cell survival and death. Dysregulation of Bcl-2 family has been demonstrated in a wide spectrum of human cancers, including gastrointestinal cancers. Therefore, targeting the Bcl-2 family of proteins represents a promising therapeutic approach for these malignancies. Recent advances have yielded small molecules that have close structural or functional similarity to BH3-only proteins and are therefore named BH3 mimetics. Of these BH3 mimetics, obatoclax, (-)-gossypol, and ABT-263 are currently in clinical trials for multiple cancers. Growing evidence indicates that these BH3 mimetics not only induce apoptosis, but also regulate autophagy which may serve as a pro-survival or pro-death mechanism to counteract or mediate the cytotoxicity of BH3 mimetics. This review discusses the role of autophagy in cell-fate decision upon BH3 mimetics treatment. Further exploration of our understanding of the association between autophagy and cellular outcomes in response to BH3 mimetics treatment will likely offer improved therapies for patients with cancer.

Prenatal loud music and noise: differential impact on physiological arousal, hippocampal synaptogenesis and spatial behavior in one day-old chicks

Prenatal auditory stimulation in chicks with species-specific sound and music at 65 dB facilitates spatial orientation and learning and is associated with significant morphological and biochemical changes in the hippocampus and brainstem auditory nuclei. Increased noradrenaline level due to physiological arousal is suggested as a possible mediator for the observed beneficial effects following patterned and rhythmic sound exposure. However, studies regarding the effects of prenatal high decibel sound (110 dB; music and noise) exposure on the plasma noradrenaline level, synaptic protein expression in the hippocampus and spatial behavior of neonatal chicks remained unexplored. Here, we report that high decibel music stimulation moderately increases plasma noradrenaline level and positively modulates spatial orientation, learning and memory of one day-old chicks. In contrast, noise at the same sound pressure level results in excessive increase of plasma noradrenaline level and impairs the spatial behavior. Further, to assess the changes at the molecular level, we have quantified the expression of functional synapse markers: synaptophysin and PSD-95 in the hippocampus. Compared to the controls, both proteins show significantly increased expressions in the music stimulated group but decrease in expressions in the noise group. We propose that the differential increase of plasma noradrenaline level and altered expression of synaptic proteins in the hippocampus are responsible for the observed behavioral consequences following prenatal 110 dB music and noise stimulation.

Repetitive auditory stimulation at a critical prenatal period modulates the postnatal functional development of the auditory as well as visual system in chicks (Gallus domesticus)

The extrinsic sensory stimulation plays a crucial role in the formation and integration of sensory modalities during development. Postnatal behavior is thereby influenced by the type and timing of presentation of prenatal sensory stimuli. In this study, fertilized eggs of white Leghorn chickens during incubation were exposed to either species-specific calls or no sound. To find the prenatal critical period when auditory stimulation can modulate visual system development, the former group was divided into three subgroups: in subgroup A (SGA), the stimulus was provided during embryonic day (E)10 to E16, in SGB E17- hatching, and in SGC E10-hatching. The auditory and visual perceptual learning was recorded at posthatch day (PH) 1-3, whereas synaptic plasticity (evident from synaptophysin and PSD-95 expression), was observed at E19, E20, and PH 1-3. An increased number of responders were observed in both auditory and visual preference tests at PH 1 following stimulation. Although a decrease in latency of entry and an increase in total time spent were observed in all stimulated groups, it was most significant in SGC in auditory preference and in SGB and SGC in visual preference test. The auditory cortex of SGC and visual Wulst of SGB and SGC revealed higher expression of synaptic proteins, compared to control and SGA. A significant inter-hemispheric and gender-based difference in expression was also found in all groups. These results indicate facilitation of postnatal behaviour and synaptogenesis in both auditory and visual systems following prenatal repetitive auditory stimulation, only when given during prenatal critical period of development.

Prenatal auditory stimulation alters the levels of CREB mRNA, p-CREB and BDNF expression in chick hippocampus

Prenatal auditory stimulation influences the development of the chick auditory pathway and the hippocampus showing an increase in various morphological parameters as well as expression of calcium-binding proteins. Calcium regulates the activity of cyclic adenosine monophosphate-response element binding (CREB) protein. CREB is known to play a role in development, undergo phosphorylation with neural activity as well as regulate transcription of BDNF. BDNF is important for the survival of neurons and regulates synaptic strength. Hence in the present study, we have evaluated the levels of CREB mRNA and protein along with p-CREB protein as well as BDNF mRNA and protein levels in the chick hippocampus at embryonic days (E) 12, E16, E20 and post-hatch day (PH) 1 following activation by prenatal auditory stimulation. Fertilized eggs were exposed to species-specific sound or sitar music (frequency range: 100-6300Hz) at 65dB levels for 15min/h over 24h from E10 till hatching. The control chick hippocampus showed higher CREB mRNA and p-CREB protein in the early embryonic stages, which later decline whereas BDNF mRNA and BDNF protein levels increase until PH1. The CREB mRNA and p-CREB protein were significantly increased at E12, E16 and PH1 in the auditory stimulated groups as compared to control group. A significant increase in the level of BDNF mRNA was observed from E12 and the protein expression from E16 onwards in both auditory stimulated groups. Therefore, enhanced phosphorylation of CREB during development following prenatal sound stimulation may be responsible for cell survival. Increased levels of p-CREB again at PH1 may trigger synthesis of proteins necessary for synaptic plasticity. Further, the increased levels of BDNF may also help in regulating synaptic plasticity.

Targets for molecular therapy in esophageal squamous cell carcinoma: an immunohistochemical analysis

Neoadjuvant chemotherapy may improve the outcome of esophageal cancer after esophagectomy, but is accompanied by considerable toxicity by collateral destruction of normal cells. Such side effects may be avoided by developing therapies that specifically target molecular characteristics of tumors. The aim of the present study was to determine the proportion of esophageal squamous cell carcinoma (ESCC) patients that could possibly benefit from (a combination of) currently available targeted therapies, by assessing the frequency of immunohistochemical expression of their target molecular markers in ESCC tissues. Sections from a validated tissue microarray comprising 108 ESCCs were immunohistochemically stained for Bcl-2, c-KIT, cyclo-oxygenase-2 (COX-2), cyclin D1, estrogen receptor (ER), epidermal growth factor receptor (EGFR), Her-2/neu, progesterone receptor (PR), and vascular endothelial growth factor (VEGF). VEGF, cyclin D1, EGFR, and COX-2 could be detected in 55, 42, 40, and 40%, respectively. Her-2/neu, Bcl-2, and c-KIT were detected in 12, 11, and 10% of the tumors, respectively. No nuclear expression of ER or PR was noticed. Concurrent expression of two markers was noticed in 28% of ESCCs, whereas 25% of ESCCs showed concurrent expression of three markers. The concurrent expression of two of the most frequently expressed markers (VEGF, cyclin D1, EGFR, and COX-2) ranged from 11 (COX-2 and EGFR) to 26% (cyclin D1 and VEGF). The expression of all of these four markers was seen in 5% of ESCCs. Promising targets for molecular therapy in ESCC appear to be COX-2, VEGF, EGFR, and cyclin D1, as they are frequently overexpressed. Phase II clinical studies on these molecular markers may therefore be warranted. The role for targeted therapy against ER, PR, Her-2/neu, c-KIT, or Bcl-2 in ESCC seems limited.

Calbindin D-28K and parvalbumin expression in embryonic chick hippocampus is enhanced by prenatal auditory stimulation

Calcium-binding proteins (CaBPs) buffer excess of cytosolic Ca(2+), which accompanies neuronal activity following external stimuli. Prenatal auditory stimulation by species-specific sound and music influences early maturation of the auditory pathway and the behavioral responses in chicks. In this study, we determined the volume, total number of neurons, proportion of calbindin D-28K and parvalbumin-positive neurons along with their levels of expression in the developing chick hippocampus following prenatal auditory stimulation. Fertilized eggs of domestic chicks were exposed to sounds of either species-specific calls or sitar music at 65 dB for 15 min/h round the clock from embryonic day (E) 10 until hatching. Hippocampi of developmental stages (E12, E16 and E20) were examined. With an increase in embryonic age during normal development, the hippocampus showed an increase in its volume, total number of neurons as well as in the neuron proportions and levels of expression of calbindin D-28K and parvalbumin. A significant increase of volume at E20 was noted only in the music-stimulated group compared to that of their age-matched control (p<0.05). On the other hand, both auditory-stimulated groups showed a significant increase in the proportion of immunopositive neurons and the levels of expression of calbindin D-28K and parvalbumin as compared to the control at all developmental stages studied (p<0.003). The increase in proportions of CaBP neurons during development and in the sound-enriched groups suggests an activity-dependent increase in Ca(2+) influx. The enhanced expression of CaBPs may help in cell survival by preventing excitotoxic death of neurons during development and may also be involved in long-term potentiation.

Cytotoxic effect of achatinin(H) (lectin) from Achatina fulica against a human mammary carcinoma cell line (MCF7)

The hemolymph-derived achatinin(H) (lectin) from Achatina fulica showed a marked cytotoxic effect on MCF7, a human mammary carcinoma cell line. IC(50) values as measured by the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay for achatinin(H) ranged from 6 to 10 microg/ml in the MCF7 cells. MCF7 cells showed significant morphological changes leading to cell death. The above cell death was observed after 48 h of treatment with 8 microg/ml when compared to untreated cells. Alterations in the tumor marker enzymes, as well as in antioxidant enzymes, were observed after achatinin(H) treatment. The specificity and purity of the achatinin(H) was confirmed by the Western blot assay. Achatinin(H) binding to MCF7 cells was detected by anti-achatinin(H), and visualization of the achatinin(H) binding sites on confluent MCF7 cells was confirmed by flourescein isothiocyanate conjugated secondary antibody. MCF7-treated cells fluoresced, indicating the presence of achatinin(H) binding sites. Fluorescence-activated cell sorting analysis of the cell cycle showed a significant increase in S-phase in MCF7 cells after 48 h of achatinin(H) treatment. The cells were arrested in G(2)/M phase of the cell cycle after 48 h with significant changes in cell viability. Cellular damage was confirmed by agarose gel electrophoresis with the characteristic appearance of a DNA streak in treated MCF7 cells indicating the ongoing apoptosis.

Extent, relationship and prognostic significance of apoptosis and cell proliferation in synovial sarcoma

AIMS

To analyse the extent, relationship and clinical significance of apoptosis and cell proliferation in synovial sarcoma.

METHODS

Apoptosis was detected by TUNEL, and expression of Ki-67, Bcl-2, Bax and p53 was examined immunohistochemically in 72 synovial sarcomas. Their relation and correlation with clinicopathological parameters and survival rate were analysed.

RESULTS

The average values of apoptosis index (AI) and Ki-67 labelling index (LI) were 0.76% and 28.30%, respectively. Both AI and Ki-67 LI in large-volume, high-grade and advanced-stage synovial sarcomas were significantly higher than those in small-volume, low-grade and early-stage ones (P<0.05 for all). And there was a linear relationship between AI and Ki-67 LI (r=0.751, P<0.001). All examined synovial sarcomas were positive for Bcl-2 and Bax, and only 20.8% cases showed expression of p53 protein. The expressions of Bcl-2, Bax and p53 were also significantly correlated with AI (P=0.005, P=0.002, P=0.037, respectively). In addition, patients with high AI (>0.76%) had poor prognosis (log-rank test; P=0.007).

CONCLUSIONS

Alterations in apoptosis and cell proliferation activity might be responsible for the pathogenesis and behaviour of synovial sarcoma. Increased rate of apoptosis in synovial sarcoma was considered to be an indicator of poor prognosis. In addition, apoptosis in synovial sarcoma may be controlled by multiple apoptosis-regulating mechanisms, including the Bcl-2 family and p53 protein.

Prenatal acoustic stimulation influences neuronal size and the expression of calcium-binding proteins (calbindin D-28K and parvalbumin) in chick hippocampus

Prenatal auditory enrichment by species-specific sounds and sitar music enhances the expression of immediate early genes, synaptic proteins and calcium binding proteins (CaBPs) as well as modifies the structural components of the brainstem auditory nuclei and auditory imprinting area in chicks. There is also facilitation of postnatal auditory preference of the chicks to maternal calls following both types of sound stimulation indicating prenatal perceptual learning. To examine whether the sound enrichment protocol also affects the areas related to learning and memory, we assessed morphological changes in the hippocampus at post-hatch day 1 of control and prenatally sound-stimulated chicks. Additionally, the proportions of neurons containing calbindin D-28K and parvalbumin immunoreactivity as well as their protein levels were determined. Fertilized eggs of domestic chick were incubated under normal conditions of temperature, humidity, forced draft of air as well as light and dark (12:12h) photoperiods. They were exposed to patterned sounds of species-specific and sitar music at 65 dB for 15 min per hour over a day/night cycle from day 10 of incubation till hatching. The hippocampal volume, neuronal nuclear size and total number of neurons showed a significant increase in the music-stimulated group as compared to the species-specific sound-stimulated and control groups. However, in both the auditory-stimulated groups the protein levels of calbindin and parvalbumin as well as the percentage of the immunopositive neurons were increased. The enhanced proportion of CaBPs in the sound-enriched groups suggests greater Ca(2+) influx, which may influence long-term potentiation and short-term memory.

Germline mutations of the PTCH gene in families with odontogenic keratocysts and nevoid basal cell carcinoma syndrome

BACKGROUND/AIMS

Odontogenic keratocysts (OKC) are aggressive lesions in the jaws, which can occur as isolated cases or in association with nevoid basal cell carcinoma syndrome (NBCCS). Mutations on PTCH gene have been identified in patients with NBCCS. It was hypothesized that PTCH mutations may be causative in isolated OKC. This study aims to investigate germline mutations of PTCH in families with OKC and NBCCS.

METHODS

Three Chinese families with OKC and NBCCS were enrolled in the study. The diagnosis was based on examination and medical history. Mutation analysis was performed by amplifying all exons of PTCH and sequencing the products.

RESULTS

One family with isolated OKC (family 1) and the other two families with NBCCS were diagnosed. Three novel germline mutations in PTCH were identified, including a missense mutation (p.S1089 > P) in family 1, a nonsense mutation (p.Q160X) in family 2 and a de novo mutation (c.768_777delGACAAACTTC) in family 3.

CONCLUSIONS

It is proposed that isolated OKC can be inherited in an autosomal dominant mode. The results suggest that germline mutations on PTCH can cause isolated OKC, and that the PTCH gene responsible for NBCCS plays an important role in the formation of OKCs even when they are not syndrome-related.

Expression of p53 protein in esophageal squamous cell carcinoma: relation to hypoxia-inducible factor-1alpha, angiogenesis and apoptosis

OBJECTIVES

Hypoxia-inducible factor (HIF)-1 is important in the control of transcription of several genes related to angiogenesis. We have previously reported that expression of HIF-1alpha correlates with venous invasion and clinical outcome in esophageal squamous cell carcinoma. p53 has been reported to interact with HIF-1alpha and induce ubiquitin-mediated proteosomal degradation of HIF-1alpha. The purpose of this study was to clarify whether the expression of p53 is associated with that of HIF-1alpha.

METHODS

Expression of p53, HIF-1alpha and vascular endothelial growth factor (VEGF) was examined in 81 archival surgical specimens of human esophageal squamous cell carcinoma tissue. CD34 and single-stranded DNA were used to evaluate angiogenesis and apoptosis.

RESULTS

Forty-seven of the 81 (58.0%) tumor specimens showed high levels of nuclear p53 immunoreactivity. Overexpression of p53 was observed in the early clinical stage of tumor development. Expression of p53 was not correlated with HIF-1alpha or VEGF expression, angiogenesis or apoptosis in esophageal carcinoma.

CONCLUSIONS

These results suggest that mutations in p53 play a role in carcinogenesis but not in the progression of esophageal squamous cell carcinoma. HIF-1alpha may not only be regulated by p53 but also by other factors.

Differential protein expression between esophageal squamous cell carcinoma and dysplasia, and prognostic significance of protein markers

The aim of the current study was to evaluate the protein expression involved in the progression from dysplasia to invasive esophageal squamous cell carcinomas and to analyze the prognostic value of markers. Immunohistochemistry was performed for cell cycle regulators [p53, p21, p27, p16, cyclin D1, Rb], apoptosis-related proteins [Fas, Fas-L, FADD, TRAIL, DR4, DR5, caspase-8, caspase-3, bcl-2, Bax], tumor suppressor proteins [beta-catenin, E-cadherin, FHIT, Smad 4, VHL, PTEN, KAI-1], and oncoproteins [c-myc, COX-2, EGFR]. Caspase-3, TRAIL, Fas-L, Fas, Smad 4, VHL, E-cadherin, and EGFR revealed significant differences between dysplasia and their corresponding invasive cancer portion in 25 cases. In a total of 118 cases of invasive cancer, proteins with frequent (> or = 60% of the cases) alterations were p53 (overexpression in 64% of SCCs), p27 (loss in 91%), p16 (loss in 81%), and FHIT (loss in 75%). Early clinical stage and bcl-2 immunopositivity were related to the survival rate of patients. In conclusion, caspase-3, TRAIL, Fas-L, Fas, Smad 4, VHL, E-cadherin, and EGFR may be involved in the progression from dysplasia to invasive esophageal SCCs. Clinical stage and bcl-2 are independent prognostic factors throughout the multivariate analysis.

Evaluation of expression of apoptosis-related proteins and their correlation with HPV, telomerase activity, and apoptotic index in cervical cancer

OBJECTIVE

The aim of this study was to examine the expression of apoptosis-related proteins in cervical cancer, and investigate their correlation with the apoptotic index (AI), telomerase activity, human papilloma virus (HPV) infection and clinicopathological characteristics.

METHODS

Fifty cervical cancer samples and 20 normal cervical tissues were assessed for the protein expression of survivin, Bcl-2, Cox-2, p53 and p73 by immunohistochemistry. HPV DNA was detected by PCR, telomerase activity by PCR-ELISA, and AI by TUNEL assay.

RESULTS

46/50 cervical tumors (92%) showed an increased telomerase activity as compared to 3/20 (15%) controls. 45/50 (90%) cervical tumors were positive for HPV, of which 30 were HPV-16 positive and 5 were HPV-18 positive. 24/50 (48%) tumors were positive for survivin, 14 (28%) for Bcl-2, 13 (26%) for Cox-2, 19/45 (42%) for p73, 10/45 (24%) for p53. Telomerase activity was highest in tumors with the poorest grade. A positive correlation was seen between survivin and Bcl-2, survivin and tumor stage, Bcl-2 and Cox-2, p73 and p53 and p73 and the AI. Despite the overexpression of various antiapoptotic proteins, no significant difference was observed in the AI between tumors and controls.

CONCLUSIONS

Since deregulation of the apoptotic pathway appears to occur in cervical cancer, some apoptosis-related proteins could be assessed as potential markers for progression/prognosis in cervical cancer. Additionally, newer proteins such as p73 may play a compensatory role for the nonfunctional proteins such as p53.

Heat stress induces different forms of cell death in sea anemones and their endosymbiotic algae depending on temperature and duration

Bleaching of reef building corals and other symbiotic cnidarians due to the loss of their dinoflagellate algal symbionts (=zooxanthellae), and/or their photosynthetic pigments, is a common sign of environmental stress. Mass bleaching events are becoming an increasingly important cause of mortality and reef degradation on a global scale, linked by many to global climate change. However, the cellular mechanisms of stress-induced bleaching remain largely unresolved. In this study, the frequency of apoptosis-like and necrosis-like cell death was determined in the symbiotic sea anemone Aiptasia sp. using criteria that had previously been validated for this symbiosis as indicators of programmed cell death (PCD) and necrosis. Results indicate that PCD and necrosis occur simultaneously in both host tissues and zooxanthellae subject to environmentally relevant doses of heat stress. Frequency of PCD in the anemone endoderm increased within minutes of treatment. Peak rates of apoptosis-like cell death in the host were coincident with the timing of loss of zooxanthellae during bleaching. The proportion of apoptosis-like host cells subsequently declined while cell necrosis increased. In the zooxanthellae, both apoptosis-like and necrosis-like activity increased throughout the duration of the experiment (6 days), dependent on temperature dose. A stress-mediated PCD pathway is an important part of the thermal stress response in the sea anemone symbiosis and this study suggests that PCD may play different roles in different components of the symbiosis during bleaching.

Combined evaluation of expression of telomerase, survivin, and anti-apoptotic Bcl-2 family members in relation to loss of differentiation and apoptosis in human head and neck cancers

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers, and it accounts for 5% of all adult cancers worldwide. Loss of growth control and a marked resistance to apoptosis are considered major mechanisms driving tumor progression. Little is known about the distribution of inhibitors of apoptosis in HNSCC or how they correlate with other biomarkers of malignancy, such as telomerase, an enzyme that plays a critical role in cellular immortalization. The objective of this study was to assess the protein expression of anti-apoptotic members of Bcl-2 family and survivin and correlate them with telomerase activity.

METHODS

We compared anti-apoptotic protein expression in tumor tissue sections of 50 HNSCC patients and 19 histopathologically normal tissues by immunohistochemistry and Western blotting. Apoptotic index was studied by TUNEL assay. Telomerase activity was determined by polymerase chain reaction (PCR)-enzyme-linked immunosorbent assay (ELISA).

RESULTS

Bcl-2, Bcl-XL, and survivin were found to be significantly upregulated in tumor tissues as compared with the normal tissue. Protein expression of Bcl-2 and survivin was significantly associated with the loss of differentiation in tumors and that of Bcl-XL with nodal metastasis. Telomerase activity was found to be upregulated in tumors as compared with the normal tissue (p <.001) and was found to be significantly associated with the loss of differentiation in tumors.

CONCLUSIONS

Mechanisms that promote both cell proliferation (telomerase activity) and cell survival (expression of inhibitors of apoptosis protein [IAPs]) appear to be activated in HNSCC. This is the first study of its kind to look into the correlation of the apoptotic pathway and proliferation promoting enzyme activity simultaneously in relation to loss of apoptosis and differentiation in HNSCCs. Telomerase activity in these tumors was found to be correlated with Bcl-2, Bcl-XL, and survivin overexpression and with reduced apoptosis, thereby suggesting that novel strategies can be developed to control cancer cell growth by co-targeting telomerase and apoptotic pathways.

Cytotoxicity studies of chromium(III) complexes on human dermal fibroblasts

The cytotoxicity of certain Cr(III) complexes, such as [Cr(salen)(H(2)O)(2)](+), [Cr(edta)(H(2)O)](-), [Cr(en)(3)](3+), [Cr(ox)(3)](3-), [Cr(pic)(3)], and CrCl(3), which differ in ionic character and ligand environment in human dermal skin fibroblasts, has been studied. After 72 h of exposure to 100 microM doses of chromium(III) complexes, the order in which the complexes had an inhibitory effect on cell viability was [Cr(en)(3)](3+) > [Cr(salen)(H(2)O)(2)](+) > [Cr(ox)(3)](3-) > [Cr(edta)(H(2)O)](-) > [Cr(pic)(3)] > CrCl(3). Based on viability studies it was confirmed that [Cr(en)(3)](3+), a triply charged cation, inhibits cell proliferation, and therefore, it was chosen to carry out further investigations. [Cr(en)(3)](3+), at a dose of 50 microM, was found to bring about surface morphological changes, evidenced by cellular blebbing and spike formation accompanied by nuclear damage. TEM analysis revealed substantial intracellular damage to fibroblasts in terms of the formation of apoptotic bodies and chromatin condensation, thus reflecting cell death. FACS analysis further revealed DNA damage by formation of a sub-G(1) peak with 84.2% DNA as aneuploid DNA and arrest of the G(2) / M phase of the cell cycle. Cellular DNA damage was confirmed by agarose gel electrophoresis with the characteristic appearance of a DNA streak in DNA isolated from [Cr(en)(3)](3+)-treated fibroblasts. The proposed mechanism suggests the plausible role of Cr(V), formed as a result of oxidation of Cr(III) by cellular oxidative enzymes, in the cytotoxic response. Consequently, any Cr(III) complex that is absorbed by cells and can be oxidized to Cr(V) must be considered a potential carcinogen. This has potential implications for the increased use of Cr(III) complexes as dietary supplements and highlights the need to consider the cytotoxicity and genotoxicity of a variety of Cr(III) complexes and to understand the potential hazards of Cr(III) complexes encountered in research laboratories.

Gamma radiation-induced apoptosis, G2 delay, and the risk of salivary and thyroid carcinomas?a preliminary report

BACKGROUND

While radiation has been the only well-established risk factor for salivary and thyroid cancers, the exact mechanisms remain unknown. We hypothesized that individuals with altered apoptotic response to gamma irradiation may be susceptible to salivary and thyroid cancers.

METHODS

We tested our hypothesis in a pilot case-control study of 29 patients with neoplasms of the salivary and thyroid glands and 29 cancer-free control subjects. Patients and control subjects were matched on age, sex, and ethnicity. In vitro gamma radiation-induced apoptosis in lymphocytes was quantified utilizing the TUNEL assay and flow cytometry.

RESULTS

The mean apoptotic capacity was 13.55 +/- 10.54 for control subjects, 5.75 +/- 4.96 for patients with salivary gland carcinomas (p =.003), and 6.87 +/- 4.45 for patients with thyroid carcinomas (p =.006). These differences were associated with a 10-fold increased risk of salivary gland carcinoma (odds ratio [OR] = 10.71; 95% confidence interval [CI], 1.21-94.86) and a four-fold increased risk of thyroid carcinoma (OR = 3.93; 95% CI, 0.90-17.08).

CONCLUSIONS

Our data suggests that gamma radiation-induced apoptosis may serve as a biomarker of genetic susceptibility to salivary and thyroid carcinoma, and further confirmatory studies with larger sample size are warranted.

Effect of prenatal auditory enrichment on developmental expression of synaptophysin and syntaxin 1 in chick brainstem auditory nuclei

Neural activity plays an important role in shaping the developing brain. We have determined the consequence of increased auditory stimulation on the developmental profile of synaptic proteins, synaptophysin and syntaxin 1, in the chick brainstem auditory nuclei, nucleus magnocellularis and nucleus laminaris, by immunohistochemistry and western blotting techniques. The chick embryos were provided with patterned sounds of species-specific calls or musical notes of a sitar, a stringed instrument, in a graded manner from embryonic day 10 (E10) through hatching, for 15 min every hour. During normal synaptogenesis of nucleus magnocellularis and nucleus laminaris, synaptophysin immunoreactivity increased significantly from E8 to E20, in parallel with synapse formation, and reduced at hatching. The embryos receiving species-specific sound stimuli exhibited a similar pattern with higher levels of immunoreactivity, though the difference between the study groups was not statistically significant. The music stimulated embryos showed an earlier peak at E16, followed by a gradual decline until hatching. In all three groups studied, syntaxin immunoreactivity showed a surge at E12, followed by a decline at E16 and subsequent stabilization. The stimulated groups continually expressed higher amounts of syntaxin immunoreactivity. The results suggest that prenatal sound stimulation enhances the normal pattern of synaptic protein expression in these auditory nuclei.

Apoptosis as an independent prognostic indicator in squamous cell carcinoma of the esophagus

Apoptosis plays a crucial role in determining net cell proliferation and cell turnover in various tumors. The rate of apoptosis in tumor cells has been reported to be a useful prognostic indicator in colorectal carcinoma. We examined apoptosis in 72 specimens of esophageal squamous cell carcinoma, by the terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) digoxigenin-nick end labeling (TUNEL) method. We examined correlation of apoptosis with outcome, clinicopathological features, and expression of the apoptosis-related proteins p53 and Bcl-2. The percentage of apoptotic cells, or apoptotic index (AI), ranged from 0.8 to 9.4 (mean: 3.47; SD: 2.02). Overall, 5-year survival of patients with high AI (AI > or = 5.0; n = 18) tumors was significantly higher than that of patients with low AI tumors (AI < 5.0; n = 58; 76.9% versus 44.9%; P = 0.042). AI did not correlate significantly with the clinicopathological features of patient age and sex, depth of tumor and histological differentiation, lymph node metastasis, lymphatic invasion, or venous invasion. In p53-negative tumors, the AI was significantly higher than in p53-positive tumors. We concluded that AI may be a useful prognostic indicator in esophageal squamous cell carcinoma following curative surgery, and that apoptosis in this tumor is related to relative underexpression of p53 protein.

Differential sensitivity of murine myeloid FDC-P1 cells and apoptosis resistant mutant(s) to anticancer drugs

There is growing evidence which suggests that dysregulation of apoptosis may lead to several disease states including cancer. To investigate the mechanism controlling the induction of cell death, apoptosis defective/resistant (Apt-) mutants were isolated and characterized in this study. FDC-P1, a mouse myeloid cell line that depends upon IL-3 for survival and growth but undergoes apoptosis when deprived of growth factor, was mutagenized by treatment with ethyl methane sulfonate. We selected cells that survived the growth factor deprivation but did not grow without the factor. Surviving cells were cloned by limiting dilution and four clones that showed the least morphological characteristics and biochemical changes of apoptosis were chosen. Unlike the parent FDC-P1, these mutants were cross resistant to apoptosis induced by a variety of antitumor drugs such as Adriamycin, Dexamethasone, VP-16, as well as reactive oxygen species (ROS) generated by xanthine/xanthine oxidase (X/XO). We used one of these Apt- mutant to test candidate death genes. Our findings suggest that the preferential increase in Bax/Bcl-2 ratio, p53, c-Myc, Caspase-3 and decrease in AP-1 on treatment with various anticancer drugs may contribute to the preferential apoptotic response in FDC-P1 cells but to varying degrees. Whereas, the higher constitutive level of antioxidant enzymes superoxide dismutase and catalase in the Apt- mutant may contribute at least in part to its resistance.

Differential gene expression in apoptosis: identification of ribosomal protein S29 as an apoptotic inducer

To identify genes that are specifically involved in apoptosis, poly(A)(+) RNAs were isolated from untreated control rat thymocytes and from adriamycin-induced apoptotic thymocytes. Directionally cloned cDNA libraries were then constructed in UNIZAP-XR vectors followed by biotin-based subtractive hybridization. Three clones were confirmed to be differentially expressed by dot blotting. Sequence analysis revealed homology to two genes previously identified, whereas one clone was novel and did not have homology to any known sequence. One clone was identical to the ribosomal protein S29, and the other was homologous to L8 ribosomal protein. Northern blot analysis revealed a marked increase in the expression of mRNA encoding ribosomal protein S29 in the apoptotic thymocytes compared to the controls. Transfection studies revealed that enhanced S29 expression resulted in increased apoptosis in rat thymocytes and HeLa cells as assessed by various morphological and biochemical characteristics, including cell shrinkage, chromatin condensation, membrane blebbing, formation of apoptotic bodies, TUNEL, FACS, and internucleosomal DNA fragmentation. This was accompanied by upregulation of p53, Caspase 3, and bax, whereas bcl-2 was downregulated as revealed by Western blotting. The current findings provide the first hint of a role for ribosomal protein S29 in the apoptotic process.