Mutations that disrupt PHOXB interaction with the neuronal calcium sensor HPCAL1 impede cellular differentiation in neuroblastoma

Heterozygous germline mutations in PHOX2B, a transcriptional regulator of sympathetic neuronal differentiation, predispose to diseases of the sympathetic nervous system, including neuroblastoma and congenital central hypoventilation syndrome (CCHS). Although the PHOX2B variants in CCHS largely involve expansions of the second polyalanine repeat within the C-terminus of the protein, those associated with neuroblastic tumors are nearly always frameshift and truncation mutations. To test the hypothesis that the neuroblastoma-associated variants exert their effects through loss or gain of protein-protein interactions, we performed a large-scale yeast two-hybrid screen using both wild-type (WT) and six different mutant PHOX2B proteins against over 10 000 human genes. The neuronal calcium sensor protein HPCAL1 (VILIP-3) exhibited strong binding to WT PHOX2B and a CCHS-associated polyalanine expansion mutant but only weakly or not at all to neuroblastoma-associated frameshift and truncation variants. We demonstrate that both WT PHOX2B and the neuroblastoma-associated R100L missense and the CCHS-associated alanine expansion variants induce nuclear translocation of HPCAL1 in a Ca(2+)-independent manner, while the neuroblastoma-associated 676delG frameshift and K155X truncation mutants impair subcellular localization of HPCAL1, causing it to remain in the cytoplasm. HPCAL1 did not appreciably influence the ability of WT PHOX2B to transactivate the DBH promoter, nor did it alter the decreased transactivation potential of PHOX2B variants in 293T cells. Abrogation of the PHOX2B-HPCAL1 interaction by shRNA knockdown of HPCAL1 in neuroblastoma cells expressing PHOX2B led to impaired neurite outgrowth with transcriptional profiles indicative of inhibited sympathetic neuronal differentiation. Our results suggest that certain PHOX2B variants associated with neuroblastoma pathogenesis, because of their inability to bind to key interacting proteins such as HPCAL1, may predispose to this malignancy by impeding the differentiation of immature sympathetic neurons.

Low prevalence of human papillomavirus (HPV) in Chinese patients with breast cancer

This retrospective study investigated the presence of human papillomavirus (HPV) in Chinese women with breast cancer, and the correlation between HPV infection and carcinogenesis. Tumour and non-cancerous breast tissue samples were obtained from 62 female patients with breast cancer; normal breast tissue samples were obtained from 46 women without breast cancer. HPV DNA was detected by nested polymerase chain reaction using consensus primers; HPV subtypes were determined by reverse dot blot and pyrosequencing analyses. HPV was found in tumour tissue samples from four of the 62 patients (6.5%), while no HPV DNA was detected in either the non-cancerous samples from patients with breast cancer or from the normal breast tissue controls. Of the four HPV-positive cases, three were HPV 16 positive (75%) and one was HPV 18 positive (25%). The low frequency of HPV detected in this study suggests that this infection is not a major risk factor in breast cancer development.

FP3: a novel VEGF blocker with antiangiogenic effects in vitro and antitumour effects in vivo

BACKGROUND Vascular endothelial growth factor (VEGF) is a critical promoter of blood vessel growth during embryonic development and neovascularisation in tumours. VEGF serves as a logical target for antiangiogenic cancer therapy because of its fundamental role in tumour angiogenesis. This study is to investigate the inhibitory effects of FP3, a novel VEGF blocker, on angiogenesis in vitro and tumour growth in vivo. METHODS The inhibitory effects of FP3 on angiogenesis in vitro were evaluated by using human umbilical vein endothelial cells (HUVECs) and rat aortic ring. The inhibitory effects of FP3 on tumour growth and angiogenesis in vivo were evaluated in a human non-small-cell lung cancer (NSCLC) cell line A549 tumour xenograft model with the methods of tumour growth regression assay and immunohistochemical staining, respectively. RESULTS In experiments with HUVECs, FP3 inhibited cell proliferation and migration. In rat aortic ring assay, FP3 suppressed VEGF-induced vessel sprouting. In tumour growth regression assay, FP3 significantly blocked the growth of A549 tumour in the subcutaneous tumour xenograft model and dramatically decreased the vessel density of tumour. CONCLUSIONS FP3 has excellent inhibitory effects on tumour angiogenesis both in vitro and in vivo, therefore it could be used as an effective antiangiogenic agent.

Prevalence of human papillomavirus in Chinese patients with colorectal cancer

AIM

The prevalence of human papillomavirus (HPV) was determined in Chinese patients with colorectal cancer (CRC). The study also aimed to determine whether the HPV DNA peripheral blood (PB) assay can be used to diagnose HPV-related CRC.

METHOD

Tumour tissue, noncancerous colorectal tissue and whole-blood samples were obtained from 96 patients with CRC. In addition, 32 colorectal tissue samples were harvested from patients without CRC, and 48 whole-blood samples were collected from healthy blood donors. HPV DNA was detected by means of a nested polymerase chain reaction (PCR) using consensus primers, and HPV genotypes were determined by reverse Southern blot and pyrosequencing.

RESULTS

HPV DNA was detected in 32 of the 96 patients with CRC, and colorectal tissues from the 32 control patients without CRC were negative for HPV DNA (P < 0.001). Among 48 healthy donors, three had detectable levels of HPV DNA in their PB. Patients with CRC did not have significantly higher levels of HPV DNA than controls. The HPV prevalence in tumour tissues was higher than that in noncancerous colorectal tissues (P < 0.001) or that in PB samples (P < 0.001). No correlation between the presence of HPV and demographic or medical characteristics was observed. HPV 16 was the viral type most frequently detected and was found in 33 (94%) of 35 HPV-positive patients.

CONCLUSION

HPV infection may be a risk factor for CRC. However, detection of HPV DNA in PB does not appear to reflect the HPV status of CRC.

Silencing of ferrochelatase enhances 5-aminolevulinic acid-based fluorescence and photodynamic therapy efficacy

Background:

Recurrence of glioma frequently occurs within the marginal area of the surgical cavity due to invading residual cells. 5-Aminolevulinic acid (5-ALA) fluorescence-guided resection has been used as effective therapeutic modalities to improve discrimination of brain tumour margins and patient prognosis. However, the marginal areas of glioma usually show vague fluorescence, which makes tumour identification difficult, and the applicability of 5-ALA-based photodynamic therapy (PDT) is hampered by insufficient therapeutic efficacy in glioma tissues.

Methods:

To overcome these issues, we assessed the expression of ferrochelatase (FECH) gene, which encodes a key enzyme that catalyses the conversion of protoporphyrin IX (PpIX) to heme, in glioma surgical specimens and manipulated FECH in human glioma cell lines.

Results:

Prominent downregulation of FECH mRNA expression was found in glioblastoma tissues compared with normal brain tissues, suggesting that FECH is responsible for PpIX accumulation in glioblastoma cells. Depletion of FECH by small interference RNA enhanced PpIX fluorescence after exposure to 5-ALA concomitant with increased intracellular PpIX accumulation in glioma cells. Silencing of FECH caused marked growth inhibition and apoptosis induction by PDT in glioma cells.

Conclusion:

These results suggest that knockdown of FECH is a potential approach to enhance PpIX fluorescent quality for optimising the subjective discrimination of vague fluorescence and improving the effect of 5-ALA-PDT.

Identification of claudin-4 as a marker highly overexpressed in both primary and metastatic prostate cancer

In the quest for markers of expression and progression for prostate cancer (PCa), the majority of studies have focussed on molecular data exclusively from primary tumours. Although expression in metastases is inferred, a lack of correlation with secondary tumours potentially limits their applicability diagnostically and therapeutically. Molecular targets were identified by examining expression profiles of prostate cell lines using cDNA microarrays. Those genes identified were verified on PCa cell lines and tumour samples from both primary and secondary tumours using real-time RT–PCR, western blotting and immunohistochemistry. Claudin-4, coding for an integral membrane cell-junction protein, was the most significantly (P<0.00001) upregulated marker in both primary and metastatic tumour specimens compared with benign prostatic hyperplasia at both RNA and protein levels. In primary tumours, claudin-4 was more highly expressed in lower grade (Gleason 6) lesions than in higher grade (Gleason ⩾7) cancers. Expression was prominent throughout metastases from a variety of secondary sites in fresh-frozen and formalin-fixed specimens from both androgen-intact and androgen-suppressed patients. As a result of its prominent expression in both primary and secondary PCas, together with its established role as a receptor for Clostridium perfringens enterotoxin, claudin-4 may be useful as a potential marker and therapeutic target for PCa metastases.

Healthcare worker's perceptions of barriers to care by immigrant women with postpartum depression: an exploratory qualitative study

OBJECTIVE

We interviewed healthcare workers working in Toronto, Canada, regarding their experience of providing care to recent immigrant women suffering from postpartum depression. The objective was two-fold: 1) to identify potential barriers to care that recent immigrant women may encounter as perceived by healthcare workers; and 2) to identify challenges healthcare workers felt that they faced as providers of care to this population.

METHODS

Qualitative semi-structured interviews were conducted with 16 key informants from various disciplines employed by healthcare agencies providing care to postpartum immigrant women in Toronto. Constant comparative analysis was used to analyze the data.

RESULTS

Two main categories of barriers to care for recent immigrant women were identified: 'practical barriers' and 'culturally determined barriers'. Practical barriers included knowing where and how to access services, and language difficulties. Cultural barriers included fear of stigma and lack of validation of depressive symptoms by family and society. The challenges experienced by healthcare providers working with this population were organized into two other categories: 'professional limitations', and 'social/cultural barriers'. 'Professional limitations' included fear of incompetence, language barriers, and inadequate assessment tools. 'Social/cultural barriers' included the experience of cultural uncertainty.

CONCLUSIONS

The results suggest that not only are there important barriers to accessing postpartum care for recent immigrant women, but it can also be challenging for healthcare workers to deliver such needed care. Understanding some of these barriers and challenges from the perspective of healthcare providers is an important step to remedying gaps and obstacles in the service system.

The clinical value of hepatocyte growth factor and its receptor--c-met for liver cancer patients with hepatectomy

BACKGROUND

To study the dynamic change of hepatocyte growth factor after hepatectomy in patients with primary liver cancer, and to analyse the prognostic value of hepatocyte growth factor and c-met for these patients.

METHODS

Thirty-one consecutive patients undergoing partial hepatectomy for liver cancer were studied. Serum hepatocyte growth factor level was determined by using enzyme-linked immunosorbent assay kit before and after operation, respectively. C-met protein and MRNA expressions in cancerous and paracancerous tissues were examined by immunohistochemical and RT-PCR methods, respectively. The correlations between clinical-pathologic parameters and the expressions of hepatocyte growth factor in serum and c-met in cancerous tissues were analysed, respectively.

RESULTS

Liver cancer patients had a significantly higher level of serum hepatocyte growth factor than normal controls (1.0424+/-0.498 ng/ml versus 0.685+/-0.115 ng/ml, p=0.008). Serum hepatocyte growth factor level was positively affected by tumour size, node cirrhosis, portal vein tumour thrombi, cholangiocarcinoma (including combined hepatocellular carcinoma), poorly differentiated hepatocellular carcinoma and tumour recurrence or metastases. After hepatectomy, serum hepatocyte growth factor level peaked on the third postoperative day, and then declined, but did not return to normal level on the postoperative day 10. From the preoperative day to postoperative day 10, the level of serum hepatocyte growth factor had a decrease of percent (85.33+/-10.2%) in the group with large tumours (>5 cm), but an elevation of percent (121.9+/-10.3%) in the group with small tumours (<or=5 cm). From the preoperative day to postoperative day 3, the level of serum hepatocyte growth factor had a higher elevation in the group with major resection than in the group with local resection (p=0.016). Moderately or strongly positive expression of c-met protein was observed in 27 cancerous regions (27/31), and only in 5 paracancerous regions. The intensive expression of c-met MRNA was 100% (31/31) detectable in the cancerous tissues, but only 22.6% (7/31) in the paracancerous tissues. C-met protein expression in cancerous tissues was correlated with portal vein tumour thrombi, cholangiocarcinoma and tumour recurrence or metastases, and the expression in paracancerous tissues was correlated with node cirrhosis. No significant correlation was observed between the hepatocyte growth factor in serum and c-met in cancerous tissues.

CONCLUSION

The over-expressions of the hepatocyte growth factor and c-met indicates an adverse prognosis for patients with liver cancer. The sustained high level of serum hepatocyte growth factor after hepatectomy may be a factor related to early tumour recurrence and metastasis. Liver regeneration may be a main factor leading to high level of serum hepatocyte growth factor in early postoperative stage.

Employment of liver tissue slice analysis to assay hepatotoxicity linked to replicative and nonreplicative adenoviral agents

Whereas virotherapy has emerged as a novel and promising approach for neoplastic diseases, appropriate model systems have hampered preclinical evaluation of candidate conditionally replicative adenovirus agents (CRAds) with respect to liver toxicity. This is due to the inability of human viral agents to cross species. We have recently shown the human liver tissue slice model to be a facile means to validate adenoviral replication. On this basis, we sought to determine whether our ex vivo liver tissue slice model could be used to assess CRAd-mediated liver toxicity. We analyzed and compared the toxicity of a conditionally replicative adenovirus (AdDelta24) to that of a replication incompetent adenovirus (Adnull [E1-]) in mouse and human liver tissue slices. To accomplish this, we examined the hepatic apoptosis expression profile by DNA microarray analyses, and compared these results to extracellular release of aminotransferase enzymes, along with direct evidence of apoptosis by caspase-3 immunhistochemical staining and TUNEL assays. Human and mouse liver tissue slices demonstrated a marked increase in extracellular release of aminotransferase enzymes on infection with AdDelta24 compared to Adnull. AdDelta24-mediated liver toxicity was further demonstrated by apoptosis induction, as detected by caspase-3 immunohistochemical staining, TUNEL assay and microarray analysis. In conclusion, concordance of CRAd-mediated apoptosis in both the human and the mouse liver tissue slice models was demonstrated, despite the limited replication ability of CRAds in mouse liver slices. The results of this study, defining the CRAd-mediated apoptosis gene expression profiles in human and mouse liver, may lay a foundation for preclinical liver toxicity analysis of CRAd agents.

[The medium conditioned incubation with rat heart cells maintains the properties of ES cells]

17 kinds of conditioned media were selected by plating tests, propagation and other tests with two cell lines, C-19-2 and MESPU-13. The results suggested that the rat heart cells conditioned media (RH-CM) can inhibit the spontaneous differentiation effectively, maintain the normal diploid karyotypes and promote adherence and proliferation of mouse ES cells. The ES cells were propagated in RH-CM to the 20th passage remaining their pluripotent in vivo and in vitro differentiation ability. RH-CM can be used as supplement of ES cell media. ES cells which are cultured in media containing 70% RH-CM and on PMEF feeder can maintain their undifferentiation state and diploid karyotype. RT-PCR detection suggested that there was mLIF expression in rat heart cells.

Overexpression of GDNF induces and maintains hyperinnervation of muscle fibers and multiple end-plate formation

This study examined the role of glial cell line-derived neurotrophic factor (GDNF) in synaptic plasticity at the developing neuromuscular junction. Transgenic mice overexpressing GDNF in skeletal muscle under the myosin light chain-1 promoter were isolated. Northern blot and ELISA at 6 weeks of age indicated that GDNF mRNA and protein levels were elevated threefold in the lateral gastrocnemius muscle (LGM) of the GDNF-transgenic animals. Histochemical examination of LGM tissue sections at 6 weeks of age revealed a 70% increase in the number of cholinesterase-positive end plates without changes in end-plate area. Multiple end plates on a single muscle fiber were also observed, in addition to multiple axonal processes terminating on individual end plates. No change in the number of spinal motoneurons, overall LGM size, or muscle type composition was observed. Finally, overexpression of GDNF in muscle caused hypertrophy of neuronal somata in dorsal root ganglia without affecting their number. These findings demonstrate that overexpression of a single neurotrophic factor in skeletal muscle induces multiple end-plate formation and maintains hyperinnervation well beyond the normal developmental period. We suggest that GDNF, a muscle-derived motoneuron neurotrophic factor, serves an important role in the regulation of synaptic plasticity in the developing and adult neuromuscular junction.

Lobeline inhibits the neurochemical and behavioral effects of amphetamine

Lobeline interacts with the dopamine transporter and vesicular monoamine transporter, presynaptic proteins involved in dopamine storage and release. This study used rodent models to assess lobeline-induced inhibition of the neurochemical and behavioral effects of amphetamine. Rat striatal slices were preloaded with [(3)H]dopamine and superfused with lobeline for 30 min, and then with d-amphetamine (0.03-3.00 microM) plus lobeline for 60 min. As predicted, lobeline (1-3 microM) intrinsically increased (3)H overflow but did not inhibit d-amphetamine-evoked (3)H overflow. Consequently, the effect of lobeline on d-amphetamine-evoked endogenous dopamine and dihydroxyphenylacetic acid overflow was assessed. Lobeline (0.1-1 microM) inhibited d-amphetamine (1 microM)-evoked dopamine overflow but did not inhibit electrically evoked (3)H overflow, indicating a selective inhibition of this effect of d-amphetamine. To determine whether the in vitro results translated into in vivo inhibition, the effect of lobeline (0.3-10.0 mg/kg) pretreatment on d-amphetamine (0.1-1.0 mg/kg)-induced hyperactivity in rats and on d-methamphetamine (0.1-3.0 mg/kg)-induced hyperactivity in mice was determined. Doses of lobeline that produced no effect alone attenuated the stimulant-induced hyperactivity. Lobeline also attenuated the discriminative stimulus properties of d-methamphetamine in rats. Acute, intermittent, or continuous in vivo administration of lobeline (1-30 mg/kg) did not deplete striatal dopamine content. Thus, lobeline inhibits amphetamine-induced neurochemical and behavioral effects, and is not toxic to dopamine neurons. These results support the hypothesis that lobeline redistributes dopamine pools within the presynaptic terminal, reducing pools available for amphetamine-induced release. Collectively, the results support a role for lobeline as a potential pharmacotherapy for psychostimulant abuse.

Acute and chronic effects of nornicotine on locomotor activity in rats: altered response to nicotine

RATIONALE

Nicotine, a tobacco alkaloid, is known to be important in the acquisition and maintenance of tobacco smoking. Nornicotine, an active nicotine metabolite, stimulates nicotinic receptors and may produce psychomotor effects similar to nicotine.

OBJECTIVE

The present study determined the effects of acute and repeated administration of nornicotine on locomotor activity and compared its effects with those of nicotine.

METHODS

R(+)-Nornicotine (0.3-10 mg/kg), S(-)-nornicotine (0.3-10 mg/kg), S(-)-nicotine (0.1-1 mg/kg) or saline was administered s.c. to rats acutely or repeatedly (eight injections at 48-h intervals). Activity was recorded for 50 min immediately after each injection.

RESULTS

S(-)-Nicotine produced transient hypoactivity, followed by dose-related hyperactivity. Repeated S(-)-nicotine administration resulted in tolerance to the hypoactivity and sensitization to the hyperactivity. Subsequent testing following a saline injection revealed evidence of conditioned hyperactivity. Acute administration of 0.3 mg/kg or 1 mg/kg R(+)- or S(-)-nornicotine produced no effect. Transient hypoactivity was observed at 3 mg/kg and 10 mg/kg R(+)-nornicotine and at 10 mg/kg S(-)-nornicotine. However, rebound hyperactivity was not observed following acute administration of either nornicotine enantiomer, suggesting that nornicotine-induced psychomotor effects differ qualitatively from those of S(-)-nicotine. Repeated R(+)-nornicotine resulted in tolerance to the transient hypoactivity, however hyperactivity was not observed. Repeated S(-)-nornicotine resulted in tolerance to the hypoactivity and the appearance of hyperactivity. Repeated administration of either nornicotine enantiomer resulted in a dose-dependent alteration in response to a 1 mg/kg S(-)-nicotine challenge, suggesting some commonalities in the mechanism of action.

CONCLUSION

Nornicotine likely contributes to the neuropharmacological effects of nicotine and tobacco use.

[The relationship between apolipoprotein E gene polymorphism and coronary heart disease and arteriosclerotic cerebral infarction]

OBJECTIVE

To detect the relationship between ApoE gene polymorphism and coronary heart disease(CHD), arteriosclerotic cerebral infarction(ACI).

METHODS

Exon 4 of ApoE gene was analyzed in normal group(87 cases), CHD group(78 cases) and ACI group(55 cases) by a combination of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct AgNO(3) staining technique.

RESULTS

Between the control group and CHD group, ACI group, chi(2) test showed no significant difference in genotype of E3/E3 (P>0.5, P>0.1, respectively); while mu test showed no significant difference in allele epsilon(2)(P>0.25, P>0.1, respectively), epsilon(4)(P>0.1, P>0.25, respectively) of ApoE.

CONCLUSION

No relationship between ApoE gene polymorphism and CHD and ACI was noted in this study.

A Markov chain model to assess the efficacy of screening for non-insulin dependent diabetes mellitus (NIDDM)

BACKGROUND

The high prevalence and severe consequences of non-insulin dependent diabetes mellitus (NIDDM) in Taiwan calls for urgent measures to detect this disease in the asymptomatic phase. However, the efficacy of early detection of NIDDM is highly dependent on its natural history from the disease-free state, through the asymptomatic to the symptomatic phase and death from NIDDM or other causes.

METHODS

In order to project the above progression, a five-state illness-and-death Markov chain model was proposed to estimate these transition parameters using data from two rounds of a blood sugar screening programme for NIDDM in Puli, in central Taiwan.

RESULTS

Results showed that the annual incidence for asymptomatic NIDDM was 10.67 per 1000 (95% CI: 8.26-13.79) and the average duration between the asymptomatic and symptomatic phases (the sojourn time) was 8 years (95%CI: 5.74-11.29). The 10-year survival rate for asymptomatic NIDDM (79.35%) was better than that for symptomatic NIDDM (69.45%). Prediction of deaths from NIDDM was performed to assess how the efficacy of screening for NIDDM varied by different screening frequencies (annual, biennial, 4-yearly and the control group). Results indicated there is no substantial difference in mortality reduction from NIDDM among the annual, biennial and 4-yearly screening regimens. However, a 4-yearly screening regimen significantly reduced deaths from NIDDM by 40% (95% CI: 26-51%).

CONCLUSIONS

A long sojourn time and the substantial reduction in mortality suggest that a 4-yearly screening regime for NIDDM would be most effective and feasible in Taiwan. The proposed five-state Markov chain model can be applied to other similar NIDDM screening projects.

(S)-(-)-Cotinine, the major brain metabolite of nicotine, stimulates nicotinic receptors to evoke [3H]dopamine release from rat striatal slices in a calcium-dependent manner

Cotinine, a major peripheral metabolite of nicotine, has recently been shown to be the most abundant metabolite in rat brain after peripheral nicotine administration. However, little attention has been focused on the contribution of cotinine to the pharmacological effects of nicotine exposure in either animals or humans. The present study determined the concentration-response relationship for (S)-(-)-cotinine-evoked 3H overflow from superfused rat striatal slices preloaded with [3H]dopamine ([3H]DA) and whether this response was mediated by nicotinic receptor stimulation. (S)-(-)-Cotinine (1 microM to 3 mM) evoked 3H overflow from [3H]DA-preloaded rat striatal slices in a concentration-dependent manner with an EC50 value of 30 microM, indicating a lower potency than either (S)-(-)-nicotine or the active nicotine metabolite, (S)-(-)-nornicotine. As reported for (S)-(-)-nicotine and (S)-(-)-nornicotine, desensitization to the effect of (S)-(-)-cotinine was observed. The classic nicotinic receptor antagonists mecamylamine and dihydro-beta-erythroidine inhibited the response to (S)-(-)-cotinine (1-100 microM). Additionally, 3H overflow evoked by (S)-(-)-cotinine (10-1000 microM) was inhibited by superfusion with a low calcium buffer. Interestingly, over the same concentration range, (S)-(-)-cotinine did not inhibit [3H]DA uptake into striatal synaptosomes. These results demonstrate that (S)-(-)-cotinine, a constituent of tobacco products and the major metabolite of nicotine, stimulates nicotinic receptors to evoke the release of DA in a calcium-dependent manner from superfused rat striatal slices. Thus, (S)-(-)-cotinine likely contributes to the neuropharmacological effects of nicotine and tobacco use.

Cyclooxygenase-2 expression is up-regulated in human pancreatic cancer

A large body of evidence suggests that cyclooxygenase-2 (COX-2) is important in gastrointestinal cancer. The purpose of this study was to determine whether COX-2 was expressed in adenocarcinoma of the human pancreas. Quantitative reverse transcription-PCR, immunoblotting, and immunohistochemistry were used to assess the expression of COX-2 in pancreatic tissue. Levels of COX-2 mRNA were increased by >60-fold in pancreatic cancer compared to adjacent nontumorous tissue. COX-2 protein was present in 9 of 10 cases of adenocarcinoma of the pancreas but was undetectable in nontumorous pancreatic tissue. Immunohistochemical analysis showed that COX-2 was expressed in malignant epithelial cells. In cultured human pancreatic cancer cells, levels of COX-2 mRNA and protein were induced by treatment with tumor-promoting phorbol esters. Taken together, these results suggest that COX-2 may be a target for the prevention or treatment of pancreatic cancer.

Telomerase activity in the differentiation of benign and malignant adrenal tumors

BACKGROUND

Telomerase is an RNA-dependent DNA polymerase that extends the ends of chromosomes by synthesizing the 6 oligonucleotide repeat TTAGGG and thus serves as a marker for cellular immortality. Although absent in most adult somatic tissues, telomerase activity is present in stem cells and is reactivated in nearly all primary human malignancies. In this study we sought to determine whether tumors of the adrenal glands contain telomerase activity and whether telomerase activity can be used to differentiate benign and malignant tumors of the adrenal glands.

METHODS

Tissue was obtained from 23 specimens at adrenalectomy. Adjacent normal adrenal tissue was obtained for control. All specimens were rapidly frozen and stored at -80 degrees C until assay. Telomerase activity was determined by the telomeric repeat amplification protocol (TRAP).

RESULTS

Telomerase activity was present in 5 of 23 (22%) of the adrenal tumors. All 3 malignant tumors were strongly TRAP positive. There was a single cortical adenoma that had very weak telomerase activity. The single TRAP-positive tumor of the adrenal medulla was a ganglioneuroma.

CONCLUSIONS

Benign adrenal tumors infrequently contain telomerase activity, whereas telomerase reactivation appears to be common in malignant tumors of the adrenal glands. These data suggest that determination of telomerase activity may offer a novel way to facilitate the differentiation of benign and malignant adrenal tumors.