Aldehyde dehydrogenase is used by cancer cells for energy metabolism

We found that non-small-cell lung cancer (NSCLC) cells express high levels of multiple aldehyde dehydrogenase (ALDH) isoforms via an informatics analysis of metabolic enzymes in NSCLC and immunohistochemical staining of NSCLC clinical tumor samples. Using a multiple reaction-monitoring mass spectrometry analysis, we found that multiple ALDH isozymes were generally abundant in NSCLC cells compared with their levels in normal IMR-90 human lung cells. As a result of the catalytic reaction mediated by ALDH, NADH is produced as a by-product from the conversion of aldehyde to carboxylic acid. We hypothesized that the NADH produced by ALDH may be a reliable energy source for ATP production in NSCLC. This study revealed that NADH production by ALDH contributes significantly to ATP production in NSCLC. Furthermore, gossypol, a pan-ALDH inhibitor, markedly reduced the level of ATP. Gossypol combined with phenformin synergistically reduced the ATP levels, which efficiently induced cell death following cell cycle arrest.

Clinical implications of proliferation activity in T1 or T2 male gastric cancer patients

Proliferation activity has already been established as a prognostic marker or as a marker for anticancer drug sensitivity. In gastric cancer, however, the prognostic significance of proliferation activity is still being debated. Several studies evaluating proliferation activity using Ki-67 have shown controversial results in terms of the relationship between proliferation activity and overall survival (OS) or drug sensitivity in gastric cancer patients. Because cytoskeleton-associated protein 2 (CKAP2) staining has recently been introduced as a marker of proliferation activity, we analyzed 437 gastric cancer tissues through CKAP2 immunohistochemistry, and we evaluated the chromatin CKAP2-positive cell count (CPCC) for proliferation activity. Although the CPCC did not show any significant correlation with OS in the male, female or total number of cases, it did show a significant correlation in the T1 or T2 male patient subgroup, according to log-rank tests (P=0.001) and univariate analysis (P=0.045). Additionally, multivariate analysis with the Cox proportional hazard regression model showed a significant correlation between the CPCC and OS (P=0.039) for the co-variables of age, gender, T stage, N stage, histology, tumor location, tumor size and adjuvant chemotherapy. In male gastric cancer cell lines, faster-growing cancer cells showed higher sensitivity to cisplatin than slow-growing cells. Thus our study indicates that CPCC-measured proliferation activity demonstrates a significantly worse prognosis in T1 or T2 male gastric cancer patients. The CPCC will help to more precisely classify gastric cancer patients and to select excellent candidates for adjuvant chemotherapy, which in turn will facilitate further clinical chemotherapeutic trials.

Predisposition of genetic disease by modestly decreased expression of GCH1 mutant allele

Recently it was shown that single nucleotide polymorphisms (SNPs) can explain individual variation because of the small changes of the gene expression level and that the 50% decreased expression of an allele might even lead to predisposition to cancer. In this study, we found that a decreased expression of an allele might cause predisposition to genetic disease. Dopa responsive dystonia (DRD) is a dominant disease caused by mutations in GCH1 gene. The sequence analysis of the GCH1 in a patient with typical DRD symptoms revealed two novel missense mutations instead of a single dominant mutation. Family members with either of the mutations did not have any symptoms of DRD. The expression level of a R198W mutant allele decreased to about 50%, suggesting that modestly decreased expression caused by an SNP should lead to predisposition of a genetic disease in susceptible individuals.

The Clinical and Histopathologic Features according to Loss of LKB1 Protein Expression on Primary Lung Cancer / 결핵및호흡기질환

BACKGROUND: LKB1(STK11) is a serine/threonine kinase that functions as a tumor growth suppressor. The functions of LKB1 in lung cancer are not completely understood. This study evaluated the relationship between LKB1 protein expression and the clinicopathological features in lung cancer tissues. METHODS: The expression of LKB1 was studied in paraffin-embedded tumor blocks, which were obtained from 77 patients who had undergone surgery at Wonkwang University Hospital. The expression of the LKB1 protein was considered positive if the staining intensity in the tumor tissue adjacent to the normal airway epithelium was >30%. RESULTS: The LKB1 expression was positive in 31 (40%) of samples. Loss of LKB1 expression was significantly associated with being male, smoking history, and squamous cell carcinoma. In the peripheral sites, the loss of LKB1 expression was strongly associated with a smoking history. A loss of LKB1 expression was more frequently associated with progression according to TNM staging, particularly more than T2, N progression. CONCLUSION: There was a significant relationship between the loss of the LKB1 protein and gender, smoking history, and histological type in primary lung cancer. Although LKB1 expression was not found to be a significant prognostic factor, further studies with a larger cohort of patient's lung cancer tissue samples will be needed to confirm this.

Transient phosphorylation of tumor associated microtubule associated protein (TMAP)/cytoskeleton associated protein 2 (CKAP2) at Thr-596 during early phases of mitosis

Tumor associated microtubule associated protein (TMAP), also known as cytoskeleton associated protein 2 (CKAP2) is a mitotic spindle-associated protein whose expression is cell cycle-regulated and also frequently deregulated in cancer cells. Two monoclonal antibodies (mAbs) against TMAP/CKAP2 were produced: B-1-13 and D-12-3. Interestingly, the reactivity of mAb D-12-3 to TMAP/CKAP2 was markedly decreased specifically in mitotic cell lysate. The epitope mapping study showed that mAb D-12-3 recognizes the amino acid sequence between 569 and 625 and that phosphorylation at T596 completely abolishes the reactivity of the antibody, suggesting that the differential reactivity originates from the phosphorylation status at T596. Immunofluorescence staining showed that mAb D-12-3 fails to detect TMAP/CKAP2 in mitotic cells between prophase and metaphase, but the staining becomes evident again in anaphase, suggesting that phosphorylation at T596 occurs transiently during early phases of mitosis. These results suggest that the cellular functions of TMAP/CKAP2 might be regulated by timely phosphorylation and dephosphorylation during the course of mitosis.

Increased lysine N-methylation of a 23-kDa protein during hepatic regeneration

The methylation of a 23-kDa nuclear protein increased after partial hepatectomy and methylation returned to basal levels after the initial stage of regeneration. The methylating enzyme was partially purified from rat liver by ammonium sulfate precipitation, DEAE-anion exchange chromatography and Butyl-Sepharose chromatography. The 23-kDa protein was purified from a nuclear fraction of liver tissue with SP-Sepharose. When the 23-kDa protein was methylated with the partially purified methyltransferase and analyzed on C18 high performance liquid chromatography (HPLC), the methylated acceptor amino acid was monomethyl lysine (MML). Previously, only arginine N-methylation of specific substrate proteins has been reported during liver regeneration. However, in this report, we found that lysine N-methylation increased during early hepatic regeneration, suggesting that lysine N-methylation of the 23-kDa nuclear protein may play a functional role in hepatic regeneration. The methyltransferase did not methylate other proteins such as histones, hnRNPA1, or cytochrome C, suggesting the enzyme is a 23-kDa nuclear protein- specific lysine N-methyltransferase.

Detection and Typing of HSV-1, HSV-2, CMV and EBV by Quadruplex PCR

The development of a multiplex polymerase chain reaction (PCR) method for rapid and accurate detection and typing of herpes simplex virus type 1 (HSV-1), and type-2 (HSV-2), cytomegalovirus (CMV) and Epstein-Barr virus (EBV) is very important for clinical diagnosis to allow the deliver of therapy as early as possible. Large scale amplifications by multiplex PCR of viral DNA can lower the cost and time for viral diagnosis. In this study, therefore sensitive quadruplex PCR was achieved by optimizing parameters such as primers, and 1.5 mM magnesium and 200 uM dNTPs concentrations. The concentrations of HSV-1, HSV-2, CMV and EBV primers were 0.5, 0.3, 0.25 and 0.25 pmoles, respectively. Optimal annealing temperature was 54 degrees C. Employing these conditions, we could detect 10 copies of reconstructed template plasmid DNA, which were cloned to vectors containing target sequences of viral DNA. PCR products of 271 bp for HSV-1, 231 bp for HSV-2, 368 bp for CMV, and 326 bp for EBV were separated on 5.0% polyacrylamide gel electrophoresis and confirmed by direct sequencing. The present study showed that the quadruplex PCR assay described herein has potential application in clinical diagnosis, when rapid, accurate detection and typing of viruses HSV-1, HSV-2, CMV or EBV are necessary.

A Family with A Missense Mutation in the SCN5A Gene

Brugada syndrome, an autosomal dominantly inherited form of ventricular fibrillation, is characterized by ST-segment elevation in leads V1-3 and right bundle-branch block on surface electrocardiogram. It is caused by mutations in the cardiac sodium channel gene, SCN5A, and to the best of our knowledge, there has been no report of this mutation in Korea. Three members of a family were heterozygous for a G to T substitution at the nucleotide position 5851 in exon 28 of the SCN5A gene. This nucleotide alteration makes a missense mutation, leading to a valine to leucine substitution (V1951L), in the carboxy terminal region of the sodium channel a subunit. We report here a missense mutation in a Korean family with Brugada-type electrocardiogram.

Cysteine carboxyl O-methylation of human placental 23 kDa protein

C-Terminal carboxyl methylation of a human placental 23 kDa protein catalyzed by membrane-associated methyltransferase has been investigated. The 23 kDa protein substrate methylated was partially purified by DEAE-Sephacel, hydroxyapatite and Sephadex G-100 gel filtration chromatographies. The substrate protein was eluted on Sephadex G-100 gel filtration chromatography as a protein of about 29 kDa. In the absence of Mg2+, the methylation was stimulated by guanine nucleotides (GTP, GDP and GTPgammaS), but in the presence of Mg2+, only GTPgammaS stimulated the methylation which was similar to the effect on the G25K/rhoGDI complex. AFC, an inhibitor of C-terminal carboxyl methylation, inhibited the methylation of human placental 23 kDa protein. These results suggests that the substrate is a small G protein different from the G25K and is methylated on C-terminal isoprenylated cysteine residue. This was also confirmed by vapor phase analysis. The methylated substrate protein was redistributed to membrane after in vitro methylation, suggesting that the methylation of this protein is important for the redistribution of the 23 kDa small G protein for its putative role in intracellular signaling.