The Effects of Retinoic Acid and MAPK Inhibitors on Phosphorylation of Smad2/3 Induced by Transforming Growth Factor β1 / 결핵및호흡기질환

BACKGROUND: Transforming growth factor β (TGF-β), retinoic acid (RA), p38 mitogen-activated protein kinase (MAPK), and MEK signaling play critical roles in cell differentiation, proliferation, and apoptosis. We investigated the effect of RA and the role of these signaling molecules on the phosphorylation of Smad2/3 (p-Smad2/3) induced by TGF-β1. METHODS: A549 epithelial cells and CCD-11Lu fibroblasts were incubated and stimulated with or without all-trans RA (ATRA) and TGF-β1 and with MAPK or MEK inhibitors. The levels of p-Smad2/3 were analyzed by western blotting. For animal models, we studied three experimental mouse groups: control, bleomycin, and bleomycin+ATRA group. Changes in histopathology, lung injury score, and levels of TGF-β1 and Smad3 were evaluated at 1 and 3 weeks. RESULTS: When A549 cells were pre-stimulated with TGF-β1 prior to RA treatment, RA completely inhibited the p-Smad2/3. However, when A549 cells were pre-treated with RA prior to TGF-β1 stimulation, RA did not completely suppress the p-Smad2/3. When A549 cells were pre-treated with MAPK inhibitor, TGF-β1 failed to phosphorylate Smad2/3. In fibroblasts, p38 MAPK inhibitor suppressed TGF-β1-induced p-Smad2. In a bleomycin-induced lung injury mouse model, RA decreased the expression of TGF-β1 and Smad3 at 1 and 3 weeks. CONCLUSION: RA had inhibitory effects on the phosphorylation of Smad induced by TGF-β1 in vitro, and RA also decreased the expression of TGF-β1 at 1 and 3 weeks in vivo. Furthermore, pre-treatment with a MAPK inhibitor showed a preventative effect on TGF-β1/Smad phosphorylation in epithelial cells. As a result, a combination of RA and MAPK inhibitors may suppress the TGF-β1-induced lung injury and fibrosis.

Relationship of Vitamin D Binding Protein Polymorphisms and Lung Function in Korean Chronic Obstructive Pulmonary Disease

PURPOSE: Multiple genetic factors are associated with chronic obstructive pulmonary disease (COPD). The association of gene encoding vitamin D binding protein (VDBP, GC) with COPD has been controversial. We sought to investigate the types of GC variants in the Korean population and determine the association of GC variants with COPD and lung function in the Korean population. MATERIALS AND METHODS: The study cohort consisted of 203 COPD patients and 157 control subjects. GC variants were genotyped by the restriction fragment-length polymorphism method. Repeated measures of lung function data were analyzed using a linear mixed model including sex, age, height, and pack-years of smoking to investigate the association of GC genetic factors and lung function. RESULTS: GC1F variant was most frequently observed in COPD (46.1%) and controls (42.0%). GC1S variant (29.0% vs. 21.4%; p=0.020) and genotype 1S-1S (8.3% vs. 3.4%; p=0.047) were more commonly detected in control than COPD. According to linear mixed model analysis including controls and COPD, subjects with genotype 1S-1S had 0.427 L higher forced expiratory volume in 1 second (FEV1) than those with other genotypes (p=0.029). However, interaction between the genotype and smoking pack-year was found to be particularly significant among subjects with genotype 1S-1S; FEV1 decreased by 0.014 L per smoking pack-year (p=0.001). CONCLUSION: This study suggested that GC polymorphism might be associated with lung function and risk of COPD in Korean population. GC1S variant and genotype 1S-1S were more frequently observed in control than in COPD. Moreover, GC1S variant was more common in non-decliners than in rapid decliners among COPD.

Autophagy Activity in Pulmonary Metastatic Tumor Tissues from Colorectal Cancer: A Pilot Study

PURPOSE: Autophagy has been reported to be involved in treatment failure in tumor. We aimed to evaluate autophagy activity in tumor tissue and compare them between the recurrence and non-recurrence groups. MATERIALS AND METHODS: We analyzed expressions of autophagy-related proteins in tumor tissues which were obtained from pulmonary metastases of colorectal cancer patients by Western blot. We also analyzed autophagosomes by transmission electron microscopy. RESULTS: Tumor tissues from recurrence group showed increased levels of LC3B-II, decreased levels of p62/SQSTM1, and also a marked accumulation of autophagosomes compared with tissues from non-recurrence group. CONCLUSION: The present study suggests that autophagy may be associated with treatment failure of metastatic colorectal cancer.

The Prevalence of Human Papillomavirus Infection in Korean Non-Small Cell Lung Cancer Patients

Human papillomavirus (HPV) infection is a co-carcinogen of lung cancer and contributes to its pathogenesis. To evaluate the prevalence of HPV infection, polymerase chain reaction (PCR) was employed to detect HPV 16, 18, and 33 DNA in tumor tissues of 112 patients with non-small cell lung cancer (NSCLC) who underwent curative surgery from Jan. 1995 to Dec. 1998 at Severance Hospital, Seoul, Korea. The patients consisted of 90 men and 22 women. Nineteen patients were under 50 years old (17%), and 92 patients (82%) were smokers. Fifty-three patients had adenocarcinomas, while 59 patients had non-adenocarcinomas. Early stage (I and II) cancer was found in 64 patients (57.1%) and advanced stage (III and IV) found in 48 (42.9%). The prevalence of HPV 16, 18, and 33 were 12 (10.7%), 11 (9.8%), and 37 (33.0%), respectively. Smoking status, sex, and histologic type were not statistically different in the presence of HPV DNA. The presence of HPV 16 was more common in younger patients and HPV 18 was more common in advanced stage patients. This study showed that the prevalence rate of HPV 16 and 18 infections in NSCLC tissue was low, suggesting HPV 16 and 18 infections played a limited role in lung carcinogenesis of Koreans. However, the higher prevalence of HPV 33 infections in Korean lung cancer patients compared to other Asian and Western countries may be important and warrants further investigation.

Promoter -202 A/C Polymorphism of Insulin-like Growth Factor Binding Protein-3 Gene and Non-small Cell Lung Cancer Risk / 결핵및호흡기질환

BACKGROUND: IGFBP-3 inhibits the mitogenic and anti-apoptotic activity of IGF by blocking the binding of IGF to its receptor. However, under certain circumstances, IGFBP- 3 can enhance the activity of IGF by protecting IGF from its degradation. More than half of the inter- individual variations in IGFBP-3 levels are known to be genetically determined by the polymorphism at -202 locus of IGFBP-3 gene. METHOD: We attempted to ascertain whether A-202C poly?morphic variation of IGFBP-3 gene constitutes a risk factor for non-small cell lung cancer (NSCLC), using PCR-restriction fragment length polymorphism (RFLP). Our study included 104 NSCLC patients and 104 age-, gender-, and smoking status-matched control subjects. RESULT: In the 104 NSCLC subjects, the genotypic freque?ncies at the -202 site were as follows: AA = 67 (64.4%), AC = 35 (33.7%), and CC = 2 (1.9%). We did detect significant differences in the genotypic distribution between the NSCLC and the control subjects (pAC>CC). Using CC genotype as a reference, the odds ratio (OR) for the subjects with AC genotype was 2.60 (95% CI: 0.89 - 8.60), and the OR associated with AA genotype was 5.89 (95% CI: 1.92 - 21.16). CONCLUSION: These results indicate that the dysregulation of IGF axis should now be considered as another important risk factor for NSCLC, and a potential target for novel antineoplastic therapies and/or preventative strategies in high-risk groups.

Identification of Tumor Suppressor Loci on the Long Arm of Chromosome 15 in Primary Small Cell Lung Cancer

Small cell lung cancer (SCLC) frequently shows a loss of heterozygosity (LOH) on chromosome 15q. In order to define the commonly affected region on chromosome 15q, we tested 23 primary SCLCs by microsatellite analysis. By analyzing 43 polymorphic microsatellite markers located on chromosome 15q, we found that 14 (60.8%) of 23 tumors exhibited a LOH in at least one of the tested microsatellite markers. Two (14.3%) of the 14 tumors were found to have more than a 50% LOH on chromosome 15q. LOH was observed in five commonly deleted regions on 15q. Of those regions, LOH from D15S1012 to D15S1016 was the most frequent (47.8%). LOH was also observed in more than 20-30% of tumors at four other regions, from D15S1031 to D15S1007, from D15S643 to D15S980, from D15S979 to D15S202, and from D15S652 to D15S642. Four of the 23 tumors exhibited shifted bands in at least one of the tested microsatellite markers. Shifted bands occurred in 3.2% (29 of 914) of the loci tested. Our data suggests the presence of at least five tumor suppressor loci on chromosome 15q in SCLC, and further that these may play an important role in SCLC tumorigenesis.

Identification of Tumor Suppressor Loci on the Short Arm of Chromosome 16 in Primary Small Cell Lung Cancers / 결핵

BACKGROUND: Loss of the short arm of chromosome 16 is a frequent event in various cancers, which suggests the presence of tumor suppressor gene(s) there. To map precise tumor suppressor loci on the chromosome arm for further positional cloning efforts, we tested 23 primary small cell lung cancers. METHODS: The DNAs extracted from paraffin embedded tissue blocks with primary tumor and corresponding control tissue were investigated. Twenty polymorphic microsatellite markers located in the short arm of chromosome 16 were used in the microsatellite analysis. RESULTS: We found that six (26.1%) of 23 tumors exhibited LOH in at least one of tested microsatellite markers. Two (8.7%) of 6 tumors exhibiting LOH lost a larger area in chromosome 16p. LOH was observed in five common deleted regions at 16p. Among those areas, LOH between D16S668 and D16S749 was most frequent (21.1%). LOH was also observed at four other regions, between D16S3024 and D16S748, D16S405, D16S420, and D16S753. Six of 23 tumors exhibited shifted bands in at least one of the tested microsatellite markers. Shifted bands occurred in 3.3% (15 of 460) of the loci tested. CONCLUSION: Our data demonstrated that at least five tumor suppressor loci might exist in the short arm of chromosome 16 and that they may play an important role in small cell lung cancer tumorigenesis.