Detection of HuD transcripts by means of reverse transcriptase and polymerase chain reaction: implications for the detection of minimal residual disease in patients with small cell lung cancer

A proliferation-inducing ligand: a new biomarker for non-small cell lung cancer

To identify a proliferation-inducing ligand (APRIL) expression profile in tumor tissue and sputum of lung cancer, and evaluate the possibility of an assistant diagnosis of lung cancer by real-time fluorescence quantitative polymerase chain reaction (RTQ-PCR) in sputum as well, the authors analyzed the expression of APRIL mRNA in 75 tissue samples and 71 corresponding sputum samples of lung cancer by RTQ-PCR and analyzed their correlation. APRIL protein expression was also observed in tumor tissues by Western blot and immunohistochemistry. The expression analysis revealed APRIL expression was elevated in non-small cell lung cancer (NSCLC) and the expression of APRIL protein was located in the membrane and cytoplasm of tumor cells by immunohistochemiscal staining. Compared to benign pulmonary disease and healthy volunteers, the expression of APRIL mRNA in sputum of lung cancer was elevated (both P <. 001). When cut-off values for positivity were set at the mean + 2SD of mRNA expression in healthy volunteers, the positive rate for APRIL mRNA expression was 81.7% (58/71) in sputum samples of lung cancer, 3.2% (2/62) in benign pulmonary disease, and 1.5% (1/65) in healthy volunteers. The correlation was evident between the expression level of APRIL mRNA of tissue samples and that of sputum samples (P <. 001, r =. 702). These results support the possibility that the APRIL gene may play a key role in lung cancer, especially in NSCLC. The elevated expression level of APRIL mRNA in sputum of NSCLC suggested that APRIL mRNA may serve as an effective and convenient diagnostic biomarker for NSCLC.

The RNA-binding protein HuD: a regulator of neuronal differentiation, maintenance and plasticity

mRNA stability is increasingly recognized as being essential for controlling the expression of a wide variety of transcripts during neuronal development and synaptic plasticity. In this context, the role of AU-rich elements (ARE) contained within the 3' untranslated region (UTR) of transcripts has now emerged as key because of their high incidence in a large number of cellular mRNAs. This important regulatory element is known to significantly modulate the longevity of mRNAs by interacting with available stabilizing or destabilizing RNA-binding proteins (RBP). Thus, in parallel with the emergence of ARE, RBP are also gaining recognition for their pivotal role in regulating expression of a variety of mRNAs. In the nervous system, the member of the Hu family of ARE-binding proteins known as HuD, has recently been implicated in multiple aspects of neuronal function including the commitment and differentiation of neuronal precursors as well as synaptic remodeling in mature neurons. Through its ability to interact with ARE and stabilize multiple transcripts, HuD has now emerged as an important regulator of mRNA expression in neurons. The present review is designed to provide a comprehensive and updated view of HuD as an RBP in the nervous system. Additionally, we highlight the role of HuD in multiple aspects of a neuron's life from early differentiation to changes in mature neurons during learning paradigms and in response to injury and regeneration. Finally, we describe the current state of knowledge concerning the molecular and cellular events regulating the expression and activity of HuD in neurons.

Role of ELAV-like RNA-binding proteins HuD and HuR in the post-transcriptional regulation of acetylcholinesterase in neurons and skeletal muscle cells

Over the last few years, several laboratories have focused their attention on elucidating the molecular events that control the expression and localization of acetylcholinesterase (AChE) in neurons and skeletal muscle cells. In this context, results from a number of studies have clearly shown the important contribution of transcriptional events in regulating AChE expression. Specifically, these studies have highlighted the roles of several cis- and trans-acting factors that control transcription of the AChE gene in these excitable cells. However, it has also become apparent that changes in the transcriptional activity of the AChE gene cannot fully account for the alterations seen in the overall abundance of AChE transcripts in neurons and muscle cells placed under a variety of experimental conditions. This indicates, therefore, that post-transcriptional mechanisms also play a significant role in controlling AChE mRNA expression. With this in mind, we have recently begun to address this issue in greater detail. Here, we provide a summary of our most recent findings dealing with the post-transcriptional regulation of AChE. Together, our studies have shown so far the important contribution of an AU-rich element located in the 3'UTR of AChE transcripts and of the stabilizing RNA-binding proteins of the ELAV-like family in regulating AChE expression in differentiating neuronal and muscle cells.

Lung cancer detection by a RT-nested PCR using MAGE A1--6 common primers

BACKGROUND

Since the mortality of lung cancer patients remains very high, the development of a sensitive detection method remains an urgent task. The authors have designed common melanoma antigen gene (MAGE) primers that enable the detection of MAGE A1 to A6 subtypes simultaneously. These primers were applied to the detection of lung cancer using sputum specimens.

METHODS

The study involved, 53 cancer patients and three non-cancer groups (193 healthy people, 235 lung cancer screening group and 140 patients with benign lung diseases) were investigated. One hundred and thirty-six respiratory specimens (55 random sputa, 33 induced sputa, 40 broncho-alveolar lavage (BAL) fluids, and 8 pleural fluids) from different lung cancer patients were blindly tested. The MAGE assay was performed by RT-nested PCR, and the results obtained from sputum were compared with those obtained by telomerase assay and conventional cytology.

RESULTS

In the sputum of the non-cancer groups, the positive rates were less than 2.1%, while the detection rates were 83.3% in the cancer tissues and 54.3% in the sputa of lung cancer patients. For the random sputum samples of lung cancer patients, the detection rate was 47.5%, but in the induced sputum, BAL and pleural fluids, the detection rate was up to over 70.0%. The MAGE assay produced a higher detection rate than the telomerase assay and conventional cytology.

CONCLUSIONS

MAGE A1-6 RT-PCR, which showed high sensitivity and specificity, provides an effective means for the lung cancer detection in sputum.

Overexpression of the embryonic-lethal abnormal vision-like protein HuR in ovarian carcinoma is a prognostic factor and is associated with increased cyclooxygenase 2 expression

The human embryonic-lethal abnormal vision-like protein HuR is involved in the regulation of mRNA turnover and serves as a shuttling protein between the nucleus and the cytoplasm that stabilizes mRNAs containing adenine- and uridine-rich elements in their 3' untranslated region. We have shown recently that expression of cyclooxygenase (COX)-2 is related to poor prognosis in ovarian carcinoma. Other studies have shown that the COX-2 mRNA contains an adenine- and uridine-rich element and is stabilized by HuR. In this study, we investigated the expression and cellular distribution of HuR in 83 primary ovarian carcinomas, 16 borderline tumors of the ovary, 3 normal ovaries, and 9 ovarian carcinoma cell lines. Expression of HuR was detected in all cell lines on the mRNA and protein level and showed a predominantly nuclear staining in OVCAR-3 cells by confocal microscopy. In an immunohistochemical evaluation of human ovarian carcinomas, HuR showed a nuclear expression in 81% of tumors. In addition, a cytoplasmic expression of HuR was observed in a subgroup of 45% of ovarian carcinomas. Nuclear as well as cytoplasmic expression of HuR was significantly increased in ovarian carcinomas compared with borderline tumors or normal ovaries. In univariate analysis, a significant association between cytoplasmic HuR expression and increased COX-2 expression (P = 0.025) as well as between histological grade (P = 0.008) and mitotic activity (P = 0.002) was observed, although nuclear expression of HuR was not correlated with COX-2 expression or other clinicopathological parameters. In Kaplan-Meier survival analysis, increased cytoplasmic expression of HuR was a significant prognostic indicator for progression-free survival (P = 0.03) as well as overall survival (P = 0.007). In multivariate analysis using the Cox regression model, cytoplasmic expression of HuR was an independent prognostic parameter for reduced overall survival with a relative risk of 2.62 (95% confidence interval, 1.32-5.19). Our results suggest that there is a dysregulation of cellular distribution of the mRNA stability factor HuR in a subset of invasive ovarian carcinomas. This dysregulation appears to result in an increased expression of COX-2, an increased proliferative rate, and may lead to a reduced survival time. Additional studies are required to analyze the downstream effects of increased cytoplasmic expression of HuR. In addition, it would be interesting to investigate the prognostic role of increased cytoplasmic expression of HuR in prospective studies.

Sensitive detection of small cell lung carcinoma cells by reverse transcriptase-polymerase chain reaction for prepro-gastrin-releasing peptide mRNA

BACKGROUND

Gastrin-releasing peptide (GRP) is an autocrine growth factor in patients with small cell lung carcinoma (SCLC). The authors developed a reverse transcriptase-polymerase chain reaction (RT-PCR) assay for the detection of SCLC cells in the peripheral blood and the pleural effusion using preproGRP mRNA as a target.

METHODS

The current study was conducted to determine the utility of preproGRP-specific nested RT-PCR on the peripheral blood, bone marrow, and pleural effusion samples from 32 patients with SCLC, 39 patients with non-small cell lung carcinoma (NSCLC), 28 patients with nonmalignant pulmonary disease, and 20 healthy volunteers. The internal primers were designed to amplify a 244-base pair PCR product, a sequence encompassing exon 1 and exon 2 by the nested RT-PCR assay.

RESULTS

Amplification of the preproGRP message was detected in SCLC cell lines (LU165, SBC1, SBC2, and SBC3) but not in other NSCLC cell lines (A549, ABC1, EBC1, and Oka-1). The SCLC cells (LU165) were detected in dilutions of tumor cells of up to 10(-7) in hematopoietic cells from healthy donors. The preproGRP mRNA was detected in 16 of 32 (50%) blood samples, 2 of 11 (18%) marrow samples, and in all 6 (100%) pleural effusion samples. Blood samples gave positive results in 11 of 19 (58%) patients with extensive disease compared with 5 of 13 (38%) patients with limited disease. In contrast, only 1 blood sample (2.6%) from a patient with lung adenocarcinoma gave a positive result among patients with NSCLC. No other samples of blood, bone marrow, and pleural effusion from patients with NSCLC and none of the blood samples from patients with nonmalignant diseases and healthy volunteers were positive.

CONCLUSIONS

The current RT-PCR approach may be a sensitive and specific assay to detect SCLC cells in circulating blood as well as in pleural effusions from SCLC patients.

Detection of tumor specific gene expression in bone marrow and peripheral blood from patients with small cell lung carcinoma

BACKGROUND

Small cell lung carcinoma (SCLC) has the propensity to grow rapidly and metastasize extensively. Detection of micro-dissemination of SCLC may have clinical relevance. For its detection, tumor-specific gene expressions were examined in peripheral blood and bone marrow aspirate from patients with SCLC.

METHODS

Expression of prepro-gastrin-releasing peptide (preproGRP), neuromedin B receptor (NMB-R) and gastrin-releasing peptide receptor (GRP-R) were examined by reverse transcriptase polymerase chain reaction (RT-PCR) in peripheral blood and bone marrow aspirate from 40 untreated patients with SCLC. Control samples consisted of peripheral blood samples from 5 patients with nonsmall cell lung cancer (NSCLC) and 20 healthy volunteers.

RESULTS

Positive rates of preproGRP, NMB-R, and GRP-R in bone marrow aspirate of patients with SCLC were 23% (9/40), 8% (3/40), and 10% (4/40), respectively. Those rates in peripheral blood were 11% (4/38), 5% (2/38), and 29% (11/38), respectively. Although GRP-R expression was detected in patients with NSCLC and in healthy volunteers, preproGRP and NMB-R expressions were not detected in patients with NSCLC and in healthy volunteers. All three gene expressions in bone marrow were more frequently observed in patients with bone marrow metastasis, accessed by biopsy, than in patients without. PreproGRP gene expression in bone marrow was also more frequent in patients with bone metastasis, accessed by bone scintigram, than in patients without, and was related to poorer survival.

CONCLUSIONS

Micro-dissemination of SCLC was detectable by RT-PCR of preproGRP and NMB-R, both specific for SCLC. These gene expressions in bone marrow may be related to disease extent and prognosis.

Novel products of the HUD, HUC, NNP-1 and alpha-internexin genes identified by autologous antibody screening of a pediatric neuroblastoma library

Autologous serological screening of a cDNA expression library (SEREX) derived from childhood neuroblastoma led to the identification of 10 different antigens, including 6 novel gene products. The novel antigen 018INX was derived from a small open reading frame in a region of alpha-internexin mRNA that was previously described as 3' untranslated region. 018INX thus represents a novel type of tumor antigen. Five novel gene products were derived from NNP-1 (NNP3) and Hu genes (HuC-L, HuD3, HuDY, HuD1pro(c)). As indicated by sequence analysis, these antigens were generated by alternative splicing and/or alternative promoter usage or allelic polymorphism. mRNA expression analyses revealed different tissue restrictions of novel compared to known HuD and NNP-1 transcripts in normal and malignant tissues. The expressions patterns of distinct transcripts indicated potential clinical meanings as diagnostic and/or prognostic tissue markers. When kinetics of serum antibody titres against SEREX-defined antigens were compared to tumor load over time in our patient with neuroblastoma, we found 100-fold increases of anti-Hu and anti-018INX antibody titres preceding the clinical diagnosis of recurrent tumor growth after 2 years. When sera of pediatric patients with cancer (30) and healthy controls (30) were tested for humoral responses to SEREX-defined neuroblastoma antigens, we detected antibodies against all known antigens and NNP3 with low frequencies and titres in control sera, while anti-018INX and anti-Hu antibodies were found in cancer patients only. Our findings indicate that SEREX-defined tumor antigens might provide novel tools for understanding and treatment of this aggressive childhood malignancy.