Adjacent Non-neoplastic Lung Tissue Research Articles

MicroRNA-99b inhibits NSCLC cell invasion and migration by directly targeting NIPBL.

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide. microRNAs (miRNAs) have been confirmed as vital regulators of multiple tumors, including NSCLC. The aim of the current study was to explore the biological mechanisms of miR-99b in NSCLC progression. NSCLC tissues and adjacent matched human non-neoplastic lung tissues used in this study were collected from 50 cases of NSCLC patients. The expression of miR-99b and NIPBL in NSCLC tissues and cell lines (A549, NCI-H460, NCI-H1299 and SPC-A1) were determined by real-time-polymerase chain reaction (qRT-PCR). The NIPBL protein level was measured by Western blot. Dual-Luciferase reporter, Western blotting and qRT-PCR were carried out to verify the potential target of miR-99b. Transwell assay was used for investigating miR-99b effect on cell migration and invasion in NSCLC cells. The results of qRT-PCR indicated that the expression of miR-99b was downregulated in the NSCLC tissues and cell lines. Overexpression of miR-99b could significantly inhibit the invasion and migration capacities in NSCLC cells. Furthermore, we also determined that NIPBL was a direct target of miR-99b. Additionally, we found NIPBL was implicated in the suppressive effects on NSCLC cell invasion and migration mediated by miR-99b. In summary, miR-99b exerted anti-tumor functions in NSCLC via regulation of NIPBL, suggesting that miR-99b/NIPBL axis may be novel biomarkers for NSCLC treatments.

Unique Immune Gene Expression Patterns in Bronchoalveolar Lavage and Tumor Adjacent Non-Neoplastic Lung Tissue in Non-Small Cell Lung Cancer.

The immune cells in the local environments surrounding non-small cell lung cancer (NSCLC) implicate the balance of pro- and antitumor immunity; however, their transcriptomic profiles remain poorly understood. A transcriptomic microarray study of bronchoalveolar lavage (BAL) cells harvested from tumor-bearing lung segments was performed in a discovery group. The findings were validated (1) in published microarray datasets, (2) in an independent group by RT-qPCR, and (3) in non-diseased and tumor adjacent non-neoplastic lung tissue by immunohistochemistry and in BAL cell lysates by immunoblotting. The differential expression of 129 genes was identified in the discovery group. These genes revealed functional enrichment in Fc gamma receptor-dependent phagocytosis and circulating immunoglobulin complex among others. Microarray datasets analysis (n = 607) showed that gene expression of BAL cells of tumor-bearing lung segment was also the unique transcriptomic profile of tumor adjacent non-neoplastic lung of early stage NSCLC and a significantly gradient increase of immunoglobulin genes' expression for non-diseased lungs, tumor adjacent non-neoplastic lungs, and tumors was identified (ANOVA, p < 2 × 10-16). A 53-gene signature was determined with significant correlation with inhibitory checkpoint PDCD1 (r = 0.59, p = 0.0078) among others, where the nine top genes including IGJ and IGKC were RT-qPCR validated with high diagnostic performance (AUC: 0.920, 95% CI: 0.831-0.985, p = 2.98 × 10-7). Increased staining and expression of IGKC revealed by immunohistochemistry and immunoblotting in tumor adjacent non-neoplastic lung tissues (Wilcoxon signed-rank test, p < 0.001) and in BAL cell lysates (p < 0.01) of NSCLC, respectively, were noted. The BAL cells of tumor-bearing lung segments and tumor adjacent non-neoplastic lung tissues present a unique gene expression characterized by IGKC in relation to inhibitory checkpoints. Further study of humoral immune responses to NSCLC is warranted.

Elevated expression of STIM1 is involved in lung tumorigenesis

This study aimed to address the potential role of STIM1 (stromal interaction molecule 1) in lung tumorigenesis. Colony formation in soft agar assay and tumorigenicity in nude mice assay were conducted. Western blot, immunohistochemistry and quantitative real-time polymerase chain reaction were used to measure the STIM1 expression. The distribution of cell cycle was detected by flow cytometry assay. Our results showed that the expression of STIM1 mRNA was significantly higher in human lung tumors than that in adjacent non-neoplastic lung tissues. Significantly increased expression of STIM1 mRNA and protein was observed in 16HBE-benzo(a)pyrene (BaP) cells and in BaP-treated mice lung tissues compared with 16HBE-control cells and the control group, respectively. Silencing STIM1 inhibited the proliferation and colony formation of A549 cells in in vitro experiments, attenuated the growth of tumor xenografts of A549 cells in in vivo experiments and induced the arrest of cell cycle in the G1 phase. The markedly decreased expression of cyclin D1 protein was observed in A549-shRNA-STIM1 cells as compared to A549-shRNA-control cells. The markedly increased expression of p21 protein was observed in A549-shRNA-STIM1 cells as compared to A549-shRNA-control cells. The expression levels of β-catenin and TGIF proteins were lower in A549-shRNA-STIM1 cells than those in A549-shRNA-control cells. In conclusion, this study indicated that the elevated expression of STIM1 might be involved in lung tumorigenesis.

Identification of Reprogrammed Myeloid Cell Transcriptomes in NSCLC.

Lung cancer is the leading cause of cancer related mortality worldwide, with non-small cell lung cancer (NSCLC) as the most prevalent form. Despite advances in treatment options including minimally invasive surgery, CT-guided radiation, novel chemotherapeutic regimens, and targeted therapeutics, prognosis remains dismal. Therefore, further molecular analysis of NSCLC is necessary to identify novel molecular targets that impact prognosis and the design of new-targeted therapies. In recent years, tumor “activated/reprogrammed” stromal cells that promote carcinogenesis have emerged as potential therapeutic targets. However, the contribution of stromal cells to NSCLC is poorly understood. Here, we show increased numbers of bone marrow (BM)-derived hematopoietic cells in the tumor parenchyma of NSCLC patients compared with matched adjacent non-neoplastic lung tissue. By sorting specific cellular fractions from lung cancer patients, we compared the transcriptomes of intratumoral myeloid compartments within the tumor bed with their counterparts within adjacent non-neoplastic tissue from NSCLC patients. The RNA sequencing of specific myeloid compartments (immature monocytic myeloid cells and polymorphonuclear neutrophils) identified differentially regulated genes and mRNA isoforms, which were inconspicuous in whole tumor analysis. Genes encoding secreted factors, including osteopontin (OPN), chemokine (C-C motif) ligand 7 (CCL7) and thrombospondin 1 (TSP1) were identified, which enhanced tumorigenic properties of lung cancer cells indicative of their potential as targets for therapy. This study demonstrates that analysis of homogeneous stromal populations isolated directly from fresh clinical specimens can detect important stromal genes of therapeutic value.

High expression of kinesin light chain-2, a novel target of miR-125b, is associated with poor clinical outcome of elderly non-small-cell lung cancer patients.

Background:MiR-125b has critical role in non-small-cell lung cancer (NSCLC) cell migration, and its target genes have not been elucidated. Kinesin-1 light chain (KLC)-2 was predicted as one of miR-125b's targets by bioinformatics analysis. This study is to identify the function of KLC2 and its interaction with miR-125b in NSCLC.Methods:Kinesin-1 light chain-2 protein expression and its clinical relevance were analysed in 140 matched NSCLC and adjacent non-neoplastic lung tissues. Both KLC2 gain- and loss-of-function analyses were performed in NSCLC cell lines by transient transfection. The direct interaction between KLC2 and miR-125b was confirmed by a luciferase reporter assay and a transient co-transfection assay as well as an analysis of eight matched clinical samples.Results:KLC2 protein was upregulated in NSCLC cell lines and tissues, and was an independent predictor of poor prognosis for elderly NSCLC patients. Kinesin-1 light chain-2 remarkably enhanced the invasive and migratory ability of NSCLC cells. MiR-125b inhibited KLC2 3′-untranslated region luciferase activity and protein expression, and inversely correlated with KLC2 expression in clinical samples. Kinesin-1 light chain-2 almost completely reversed miR-125b-induced inhibition on migration and invasion.Conclusions:Kinesin-1 light chain-2 protein overexpression predicts poor survival in elderly NSCLC patients. Kinesin-1 light chain-2 acts as a proto-oncogene and a functional target of miR-125b in NSCLC cells.

Metabolic Alterations in Lung Cancer–Associated Fibroblasts Correlated with Increased Glycolytic Metabolism of the Tumor

Cancer cells undergo a metabolic reprogramming but little is known about metabolic alterations of other cells within tumors. We use mass spectrometry-based profiling and a metabolic pathway-based systems analysis to compare 21 primary human lung cancer-associated fibroblast lines (CAF) to "normal" fibroblast lines (NF) generated from adjacent nonneoplastic lung tissue. CAFs are protumorigenic, although the mechanisms by which CAFs support tumors have not been elucidated. We have identified several pathways whose metabolite abundance globally distinguished CAFs from NFs, suggesting that metabolic alterations are not limited to cancer cells. In addition, we found metabolic differences between CAFs from high and low glycolytic tumors that might reflect distinct roles of CAFs related to the tumor's glycolytic capacity. One such change was an increase of dipeptides in CAFs. Dipeptides primarily arise from the breakdown of proteins. We found in CAFs an increase in basal macroautophagy which likely accounts for the increase in dipeptides. Furthermore, we show a difference between CAFs and NFs in the induction of autophagy promoted by reduced glucose. In sum, our data suggest that increased autophagy may account for metabolic differences between CAFs and NFs and may play additional as yet undetermined roles in lung cancer.

The apoptosis of non-small cell lung cancer induced by cisplatin through modulation of STIM1

Cis-diamminedichloroplatinum (II) (cisplatin) is one of the most active antitumor agents used in human chemotherapy of non-small cell lung cancer. Cisplatin forms crosslinked DNA adducts and its cytotoxicity has been shown to be mediated by propagation of DNA damage recognition signals to downstream pathways prompting apoptosis. The steps involved in the process include changes in Ca(2+) signaling with dysregulated tumor cell turn-over. Stromal interaction molecules 1 (STIM1), as one of the most potent tumor suppressor genes, are identified as the endoplasmic-reticulum (ER) Ca(2+) sensor controlling store-operated Ca(2+) entry (SOCE) in non-excitable cells, which is main pathway to extracellular Ca(2+) influx. Its role in STIM1 cisplatin-induced apoptosis of non-small cell lung cancer was the focus of study with focus on SOCE inhibitors 2-APB- and SKF96365-cisplatin-induced apoptosis in the non-small cell lung cancer (NSCLC) cell lines A549 and H460. In this experimental model, cisplatin-induced apoptosis and decreased concentration of intracellular Ca(2+) was demonstrated. The expression of STIM1 was significantly higher in carcinoma tissue than in the adjacent non-neoplastic lung tissue. These findings support the conclusion that STIM1 may play an important role in the development of NSCLC which makes drugs that repress the expression of STIM1 to be a potential target for lung cancer therapy.

Abstract 4972: Analysis of the reprogrammed bone marrow-derived stroma in lung cancer unravels potential targets for prognosis and therapy.

Abstract Background: Lung cancer is the leading cause of cancer related mortality, with NSCLC the most prevalent form. Despite advances in treatment options (minimally invasive surgery, CT-guided radiation, novel chemotherapy regimens, targeted therapeutics) prognosis remains dismal. Most research to date has focused on cancer cell intrinsic mutagenesis (K-ras, p53, EGFR, EML4-ALK fusion), however recent studies have begun to recognize that cross talk between tumor epithelial cells and intratumoral stromal cells contributes to tumor progression. Unfortunately, little is known about the contribution or role of the stroma in NSCLC. Here, we present the first comprehensive analysis of specific individual stromal components of human NSCLC, which has led to the identification of stromal-specific activated pro-tumorigenic genes of prognostic and therapeutic potential. Materials and Methods: Surgically resected Stage I/II adenocarcinoma and matched adjacent non-neoplastic lung tissue were mechanically dissociated within 1hour of resection. Cell populations marked with specific antibodies were sorted to homogeneity by flow cytometry. RNA was isolated to construct cDNA libraries, which were deep sequenced using the Illumina HiSeq 2000. Validation of differentially regulated genes was carried out by RT-PCR and immunostaining. Mouse models of K-rasG12D and p53flox/flox derived NSCLC together with a bone marrow transplantation approach were used to determine the functional role of activated genes, and a NSCLC tissue microarray was used to ascertain their prognostic value. Results: Flow cytometry analysis revealed a 4-fold increase in the number of intratumoral hematopoietic cells, compared with adjacent non-neoplastic lung tissue. Deep RNA sequencing of two predominant myeloid specific subpopulations, CD11b+CD33+ monocytic myeloid cells and CD11b+CD33- polymorphonuclear neutrophils, revealed 783 and 938 differentially regulated genes respectively when comparing tumor vs. adjacent lung-derived cells. Many genes encoded secreted proteins such as OPN, TSP1, CCL7, and MMP12, suggesting activation of aberrant autocrine and paracrine regulatory pathways likely to support stromal-mediated tumor progression. We will present data showing the prognostic and therapeutic potential of these genes in NSCLC. Conclusions: This study is based on an emerging paradigm that activated intratumoral stromal cells play a fundamental role in promoting tumor growth. Using a unique and novel approach of quantitative analysis of individual stromal components from freshly procured NSCLC tumor tissue, we have identified differentially regulated genes previously undiscovered in traditional whole tumor profiling approaches. The activated stromal genes constitute novel therapeutic targets against lung cancer, either alone or in combination with treatments that target cancer cells. Citation Format: Anna Durrans, Dingcheng Gao, Ravi Gupta, Seongho Ryu, Navneet Narula, Kari R. Fischer, Hyejin Choi, Brendon M. Stiles, Abu Nasar, Ramana V. Davuluri, Nasser K. Altorki, Vivek Mittal. Analysis of the reprogrammed bone marrow-derived stroma in lung cancer unravels potential targets for prognosis and therapy. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4972. doi:10.1158/1538-7445.AM2013-4972

Abstract 1420: Mechanisms of stroma-derived CCL7 in promoting lung cancer.

Abstract Lung cancer is a leading cause of cancer related deaths worldwide, with non-small cell lung cancer (NSCLC) being the most prevalent form. Considerable attention has been directed to cancer cell intrinsic abnormalities (K-ras, p53, EGFR, AML-ALK4 fusions etc.), but little is known about the contribution of stromal cells to NSCLC progression. We have undertaken a comprehensive analysis to determine the contribution and biological function of the stromal cells in NSCLC. We show increased recruitment of BM hematopoietic cells in the tumor beds compared to matched adjacent non-neoplastic lung tissue in NSCLC patients. Genome-wide transcriptome analysis on specific cell populations from fresh samples of NSCLC patients identified differentially regulated genes and mRNA isoforms in NSCLC stromal cells. Genes that were successfully validated by independent RT-PCR on sorted stromal cells and tumor cells were used for further analysis. Many genes encoded secreted proteins, suggesting the activation of aberrant autocrine and paracrine regulatory loops likely to support stroma-mediated tumor progression. Among these genes, CCL7 was upregulated in myeloid progenitor cells and was selected for further investigation. Immunostaining of lung tumor and adjacent non-neoplastic tissue of patients shows highest expression of CCL7 in BM-derived cells (CD45+ cells) in the tumor. Cross species analysis showed that, consistent with the observation in human tissue, CCL7 was differentially regulated in BM derived cells in a mouse model of NSCLC generated in KrasG12D and p53-/- transgenic mice. We have genetically ablated CCL7 in the BM cells using lentiviral shRNA and BMT approaches and will discuss consequences of this ablation in CCL7-mediated crosstalk between tumor cells and stromal cells that regulate NSCLC progression. Citation Format: Hyejin Choi, Anna Durrans, Dingcheng Gao, Seongho Ryu, Nasser Altorki, Vivek Mittal. Mechanisms of stroma-derived CCL7 in promoting lung cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1420. doi:10.1158/1538-7445.AM2013-1420

MiRNAs expression profiling to distinguish lung squamous-cell carcinoma from adenocarcinoma subtypes

We investigated whether miRNA expression profiles can distinguish and predict outcome of non-small-cell lung carcinoma (NSCLC) patients with different histological subtypes. High-throughput microarray was used to measure miRNA expression levels in six NSCLC samples. Subsequently, quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to verify findings in an independent set of 54 squamous-cell lung carcinomas (SCC), 51 lung adenocarcinomas (AD), and paired adjacent non-neoplastic lung tissue. We showed that, compared to adjacent non-neoplastic lung tissues, the expressions of miR-125a-5p and let-7e were decreased in AD and SCC samples, while increased expressions of miR-93, miR-205, and miR-221 were observed in SCC samples. In addition, miR-205 expression was significantly higher in SCC patients with lymph node metastasis. Lower let-7e expression was associated with lymph node metastasis, >3 cm tumor size, and differentiation of the NSCLC AD subtype. High levels of miR-100 expression also correlated with the AD subtype in current smokers. Moreover, induction of miR-93 and miR-205 expressions and reduction of let-7e were strongly associated with shorter overall survival in SCC patients, whereas AD patient survival was only associated with reduced let-7e. We identified differential expression profiles of miRNAs in AD and SCC. More importantly, in addition to morphology and immunocytochemistry approaches, we report that miR-93, miR-205, miR-221, and let-7e may represent novel biomarkers for differential diagnosis and prognosis of certain NSCLC subtypes or be new targets of histology-specific treatments. Furthermore, our results suggest a strong correlation between high expression of miR-100 and AD patients with history of heavy smoking.

Promoter methylation of ASPP1 and ASPP2 genes in non-small cell lung cancers

To investigate the methylation status of CpG islands in the promoter region and the protein expression of ASPP1 and ASPP2 genes in non-small-cell lung cancer (NSCLC) and their relationship with cellular apoptosis and p53 gene expression. The 5'CpG island methylation patterns of ASPP1 and ASPP2 were evaluated by methylation specific polymerase chain reaction (MSP) followed by confirmation of sequencing. Immunohistochemistry was used to detect the expression of ASPP1, ASPP2 and p53 in lung carcinoma tissue samples (n = 90) and adjacent non-neoplastic lung tissue samples (n = 25). TUNEL assay was used to detect the apoptotic activity. The presence of ASPP1 methylation was significantly higher in NSCLC than that in the adjacent non-neoplastic lung tissue [42.2% (38/90) vs. 16.0% (4/25), P = 0.019]. ASPP1 promoter methylation had a close relationship with TNM stage and lymph node metastasis (P = 0.031, P = 0.030), but was not related to the age, sex, histological types and the grades of tumor differentiation (P = 0.389, P = 0.278, P = 0.570, and P = 0.103). Tumors with ASPP1 promoter methylation demonstrated a lower expression of ASPP1 as compared with those without the methylation (P = 0.002). ASPP1 expression was associated with a higher apoptotic index (AI) (P = 0.022) and a decreased p53 expression (r = -0.259, P < 0.01). Methylation in the promoter region of ASPP2 gene was not detected in lung cancer (n = 90) or adjacent non-neoplastic lung tissue (n = 25). Expression of ASPP2 protein did not correlate with AI (P = 0.282) and p53 status in NSCLC. High methylation of ASPP1 gene promoter regions is one of the important mechanisms that down-regulate its protein expression in NSCLC. ASPP1 promoter methylation may be associated with the malignant progression of the tumor, and ASPP1 expression promotes cellular apoptosis.

Downregulation of Signaling-active IGF-1 by Dipeptidyl Peptidase IV (DPP-IV)

Functioning as an extracellular protease, dipeptidyl peptidase IV (DPP-IV) preferentially cleaves the peptide bond after the penultimate proline residue. We report here that DPP-IV cleaves the first two amino acids from insulin-like growth factor 1 (IGF-1), revealed by mass spectrometry. The kinetic parameters of the proteolytic cleavage indicate that this reaction is physiologically relevant. Interestingly, truncated IGF-1 is less potent than the full-length protein in activating the IGF-1R, but binds more readily to IGF-binding protein 3 (IGFBP3). Quantitative RT-PCR showed that the level of DPP-IV mRNA is dramatically lower in lung squamous cell carcinoma tissues than in adjacent nonneoplastic lung tissues. However, this reduction was not observed in lung adenocarcinoma tissues. Our study suggests a possible link between IGF-1 and DPP-IV in cancer development in a specific tumor niche. A DPP-IV-related pathway may be important in mitigating IGF-1 signaling. Consequently, a robust IGF signaling pathway may accelerate early carcinogenesis in environments lacking DPP-IV.

Metastasis-Associated Protein 1 Nuclear Expression is Associated with Tumor Progression and Clinical Outcome in Patients with Non-small Cell Lung Cancer

Little research has been done to test the usefulness of metastasis-associated protein 1 (MTA1) as a prognostic marker for non-small cell lung cancer (NSCLC). In this study, we investigated MTA1 expression and its prognostic value for NSCLC. NSCLC surgical tissue samples were taken from 100 patients with NSCLC who had been followed up for more than 2 years. The expression of MTA1 protein was evaluated by immunohistochemistry, and the correlations between the expression of MTA1 and clinical features and the prognosis were analyzed. The difference of MTA1 protein expression between NSCLCs and their adjacent nonneoplastic lung tissues was analyzed in a tissue microarray. The change of MTA1 mRNA expression and protein expression after RNA interference (RNAi) was detected by real-time polymerase chain reaction, Western blot, and immunocytochemistry in NSCLC cell line 95D. Overexpression of MTA1 (immunoreactivity scoring >4) was shown in 61.0% of the NSCLC cases but only in 9.4% of their adjacent nonneoplastic lung tissues (p < 0.001). The MTA1 expression level was correlated with lymph node metastasis (p = 0.013) and clinical stage (p = 0.002). Survival analysis showed that the MTA1 overexpression group had a significantly shorter overall survival time than the MTA1 downexpression group (p = 0.003). However, multivariate analysis showed that MTA1 expression was not a significant and independent prognostic parameter for patients with NSCLC. After RNAi, the 95D cells exhibit consistent reduction in MTA1 mRNA expression and MTA1 protein expression. MTA1 protein expression is associated with tumor progression and clinical outcome in patients with NSCLC. Further molecular, cellular, and animal model studies on MTA1 gene will provide new clues for exploring the mechanism of carcinogenesis and tumor progression in patients with NSCLC.

Expression of connexin 43 in lung cancer and its correlation with E-cadherin

To investigate the expression of connexin 43 and E-cadherin in lung cancer and to study the interaction between the two molecules. The expression and correlation of connexin 43 and E-cadherin were evaluated by immunohistochemistry (S-P method) in 85 samples of primary squamous cell carcinoma and adenocarcinoma of the lung. In addition, connexin 43 expression vector was transfected into the lung giant cell carcinoma cell line LH(7) followed by analyses of connexin 43 and E-cadherin expressions, the growth rates and cell cycle profiles of the transfected cells. Comparing with the adjacent non-neoplastic lung tissue, expression of connexin 43 and E-cadherin was decreased in a correlative fashion in both squamous cell carcinomas and adenocarcinomas. Their expression reversely correlated to the degree of tumor cell differentiation, P-TNM stage, and status of lymph note metastasis. The expression of connexin 43 and E-cadherin increased significantly after transfection of connexin 43 expression vector into the LH(7) cells (P < 0.05). Both expressions were limited in the cytoplasm before or after the transfection. The proliferation rate of LH(7) cells was significantly decreased by connexin43 expression (P < 0.05), along with an increase of cell population at G(1) phase and a decrease of percentage of cells in S and G(2) phases (P < 0.05). Squamous cell carcinoma and adenocarcinoma of lung have a low level of connexin 43 and E-cadherin expression, which are correlated with the clinicopathologic features of the tumors. Transfection expression of connexin 43 gene induces an E-cadherin overexpression and an inhibition of LH(7) cell proliferation indicating the significant role of onnexin 43 in the regulation of cell proliferation.

Study on the relationship between telomerase gene and telomerase activity in lung cancer tissue

To investigate the relationship between the telomerase activity and telomerase component expression in lung cancer, and to explore whether telomerase activity is regulated at the gene or transcriptional level. Expression of the hTR and hTERT were detected in 68 human lung cancer tissues and responsive adjacent non-neoplastic lung tissues by semi-quantitative reverse transcription-polymerase chain reaction. Telomerase activity was detected by telomeric repeat amplification protocol. In 68 lung cancer tissues, the positive rate of the telomerase activity, hTR and hTERT expression were 79.4% (54/68), 98.5% (67/68) and 91.2% (62/68) respectively. Whereas most adjacent non-neoplastic lung tissues expressed hTR (62/68, 91.2%) also, hTERT was detected in only 7 (10.3%) normal lung tissues and no telomerase activity were detected in the 68 non-neoplastic lung cancer tissues. As compared with hTR, hTERT expression was closely related to telomerase activity. The concordance was 89.0% (121/136), whereas the concordance between telomerase and hTR was 43.4% (59/136). The results suggest that telomerase may play an important role in tumorigenesis of lung cancer. Telomerase activity may be regulated in transcription level or translation level.

Expression of human telomerase subunit genes in primary lung cancer and its clinical significance

Background. Three major components of human telomerase, RNA component (hTERC), telomerase-associated protein (TEP1), and catalytic subunit (hTERT) have been cloned recently. The aim of this study was to examine the expression of these genes and to search for clinical usefulness. Methods. Expression of these genes was evaluated by reverse transcription-polymerase chain reaction in 92 human lung cancers and in 32 non-neoplastic lung tissues. In 15 patients, both telomerase activity by telomeric repeat amplification protocol assay and expression were evaluated. Results. hTERT expression was best associated with telomerase activity with a concordance of 77%. In 92 lung cancer tissues, hTERC, TEP1, and hTERT were expressed in 100%, 93%, and 89%, respectively. Whereas most adjacent non-neoplastic lung tissues expressed hTERC and TEP1 (94% and 100%, respectively), hTERT was detected in only 1 of 32 normal lungs. However, there was no relationship between hTERT expression and clinicopathologic features. Conclusions. hTERT expression can be a surrogate for telomerase activity that may serve as a novel biomarker of lung cancer with high specificity and sensitivity.

Distribution of the Ca (Oxford) antigen in lung neoplasms and non-neoplastic lung tissues.

The Ca (Oxford) antigen was originally isolated from a malignant neoplasm and with few exceptions was reported to discriminate between malignant and non-malignant neoplasms or normal tissues. Using the Ca 1 antibody we have studied the Ca distribution in 54 lung neoplasms and adjacent non-neoplastic lung tissue. Staining of tumours was very focal and the proportion of positive cells varied from about 50% for adenocarcinomas to less than 1% for oat cell carcinomas, which were often negative. Focal cytoplasmic staining can be seen in all neoplasms, whereas membrane staining is mainly seen in their areas of glandular and squamous differentiation. We found consistently strong membrane staining of alveolar type II pneumocytes in non-neoplastic lung. This staining may be useful in differentiating type II cells from alveolar macrophages which only occasionally showed granular cytoplasmic staining, probably due to phagocytosed Ca. Mucin from tumours and bronchi did not stain but there was consistent staining of alveolar serous exudate suggesting extracellular location of Ca.