Publications by authors named "Joobae Park"

Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) is a master regulator of mitochondrial biogenesis. Reduced PGC-1α abundance is linked to skeletal muscle weakness in aging or pathological conditions, such as neurodegenerative diseases and diabetes; thus, elevating PGC-1α abundance might be a promising strategy to treat muscle aging. Here, we performed high-throughput screening and identified a natural compound, farnesol, as a potent inducer of PGC-1α.

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This study examined the impact of two single-nucleotide polymorphisms (SNPs) in the telomerase-associated protein 1 (TEP1) gene on the risk of breast, colorectal, hepatocellular, lung and stomach cancer. A significantly increased stomach cancer risk associated with the GG genotype at rs1760893 (odds ratio (OR)=1.64, 95% confidence interval (CI)=1.

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Growth pathways play key roles in longevity. The present study tested single-nucleotide polymorphisms (SNPs) in the connective tissue growth factor gene (CTGF) and the epidermal growth factor receptor gene (EGFR) for association with longevity. Comparison of allele and genotype frequencies of 12 CTGF SNPs and 41 EGFR SNPs between 440 American men of Japanese ancestry aged ≥95 years and 374 men of average life span revealed association with longevity at the p < .

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The present study was aimed at discovering DNA copy number alterations (CNAs) involved in the carcinogenesis of stomach and at understanding their clinicopathological significances in the Korean population. DNA copy numbers were analyzed using Agilent 244K or 400K array comparative genomic hybridization (aCGH) in fresh-frozen tumor and matched normal tissues from 40 gastric cancer patients. Some of the detected CNA regions were validated using multiplex ligation-dependent probe amplification (MLPA) in six of the 40 patients and customized Agilent 60K aCGH in an independent set of 48 gastric cancers.

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This study was aimed at understanding the functional and clinicopathological significance of MAPK15 alteration in gastric cancer. Genome-wide copy number alterations (CNAs) were first investigated in 40 gastric cancers using Agilent aCGH-244K or aCGH-400K, and copy number gains of MAPK15 found in aCGH were validated in another set of 48 gastric cancer tissues. The expression of MAPK15 was analyzed using immunohistochemistry in concurrent lesions of normal, adenoma, and carcinoma from additional 45 gastric cancer patients.

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Background: The level of proliferation activity is a strong prognostic or predictive indicator in breast cancer, but its optimal measurement is still in debate, necessitating new proliferation markers. In the present study, the prognostic significance of the CKAP2-positive cell count (CPCC), a new proliferation marker, was evaluated, and the results were compared with those for the mitotic activity index (MAI).

Methods: This study included 375 early-stage breast cancer samples collected from two institutions between 2000 and 2006.

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Gastric cancer (GC) is the most common malignancy. The incidence rates remain remarkably high in East Asians. Although genome-wide association studies in the Han Chinese and Japanese populations have so far yielded susceptibility loci for GC, these findings need to be validated in an independent ethnic group.

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Purpose: This study was aimed at analyzing the recurrence-related prognostic significance of 12 candidate molecular biomarkers in node-negative stage I-II non-small cell lung cancer (NSCLC).

Experimental Design: We retrospectively analyzed promoter methylation of eight genes using methylation-specific PCR in formalin-fixed and paraffin-embedded tissues from 328 node-negative stage I-II NSCLCs. The expression of Bcl-2, E-cadherin, p53, and p63 proteins was also assessed by immunohistochemistry.

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Background: The objective of this study was to discover molecular biomarkers associated with the recurrence of esophageal squamous cell carcinoma (ESCC).

Methods: The authors retrospectively analyzed the hypermethylation status of 11 genes using methylation-specific polymerase chain reaction (PCR) and the expression of epidermal growth factor receptor (EGFR), O-6 methylguanine-DNA methyltransferase (MGMT), tumor protein 53 (p53), and transforming growth factor β (TGFβ) using immunohistochemistry in 329 formalin-fixed, paraffin-embedded ESCCs.

Results: Recurrence was identified in 151 of 329 ESCCs (46%) at a median follow-up of 4.

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Background: The prognostic significance of cyclin A2 overexpression in non-small cell lung cancer (NSCLC) is controversial.

Methods: To understand the effect of cyclin A2 on recurrence in NSCLC, we retrospectively analyzed the expression of Bcl-2, cyclin A2, E-cadherin, Ki-67, and p53 using immunohistochemistry in 635 NSCLCs.

Results: Overexpression of cyclin A2 was found in 466 (73%) of 635 NSCLCs, and recurrence occurred in 291 (46%) of 635 NSCLCs with a median follow-up of 5.

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Background: Compared to well-known function of cyclin D1 in lung cancer, the role of cyclin D2 is not clear. This study was aimed at understanding the clinicopathological significance of cyclin D2 in primary non-small cell lung cancer (NSCLC).

Methods: We retrospectively analyzed expression statuses of cyclin D1, cyclin D2, p16, p21, p27, Ki-67, and phospho-pRb (Ser-807/811) using immunohistochemistry in 626 NSCLCs.

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CKAP2 plays crucial roles in proper chromosome segregation and maintaining genomic stability. CKAP2 protein showed cell-cycle-dependent expression, which reached a maximum level at the G2/M phase and disappeared at the onset of G1 phase. To elucidate the mechanisms underlying cell cycle-dependent expression of CKAP2, we cloned and analyzed the human CKAP2 promoter.

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Purpose: Proliferation activity has long been known to be one of the strongest prognostic factors in many different cancers. Nevertheless, microscopic evaluation of mitotic figures remains time-consuming and, furthermore, is relatively subjective. As the expression of cytoskeleton-associated protein 2 (CKAP2) is closely related to the mitotic phase, CKAP2 was evaluated as a surrogate mitotic figure (MF) marker.

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Background: The objective of this was to identify functional single nucleotide polymorphisms (SNPs) in cyclin-dependent kinases (CDKs) and cyclins that are associated with risk of human cancer.

Methods: First, 45 SNPs in CDKs and cyclins were analyzed in 106 lung cancers and 108 controls for a pilot study. One SNP (reference SNP [rs] 769236, +1 guanine to adenine [G→A]) at the promoter region of cyclin A2 (CCNA2) also was analyzed in 1989 cancers (300 breast cancers, 450 colorectal cancers, 450 gastric cancers, 367 hepatocellular carcinomas, and 422 lung cancers) and in 1096 controls.

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Article Synopsis
  • This study investigates the loss of cystatin M in breast cancer and its clinicopathological implications, focusing on the factors contributing to this loss.
  • Using immunohistochemical analysis, the researchers examined the expression of various receptors in patients with ductal carcinoma in situ (DCIS) and invasive breast cancer (IBC), along with evaluating the methylation status of the CST6 gene associated with cystatin M.
  • The results indicated that cystatin M loss is significantly more common in invasive breast cancer than in DCIS and is linked to the loss of estrogen receptor (ER), progesterone receptor (PR), and HER4, particularly in triple-negative IBCs.
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During mitosis, regulation of protein structures and functions by phosphorylation plays critical roles in orchestrating a series of complex events essential for the cell division process. Tumor-associated microtubule-associated protein (TMAP), also known as cytoskeleton-associated protein 2 (CKAP2), is a novel player in spindle assembly and chromosome segregation. We have previously reported that TMAP is phosphorylated at multiple residues specifically during mitosis.

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Previously, we reported the phosphorylation of moesin induced by electroconvulsive shock in rat brain and by glutamate in immortalized rat hippocampal cells. However, the function of phosphorylated moesin in differentiated neurons is not well understood. In this study, we observed that glutamate induces phosphorylation of ezrin/radixin/moesin proteins (ERM) in cultured hippocampal cells and that phosphorylated ERM localizes at the newly formed filopodia of neurites.

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Moesin is a member of ERM family proteins which act as the cross-linkers between plasma membrane and actin-cytoskeleton and is activated by phosphorylation at Thr-558. In neurons, suppression of radixin and moesin alters the growth cone morphology. However, the significance of phosphorylation of ERM proteins in neuronal cells has not been fully investigated.

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We have previously shown that in PC12 cells: (1) high extracellular KCl induces moesin phosphorylation, an event which was dependent on chloride channel activation, and (2) NGF induces moesin phosphorylation which is required for neurite outgrowth. These results suggest that NGF-induced intracellular signaling and neurite outgrowth is also mediated by activation of anion channels. Using a patch-clamp technique, we found that NGF treatment increased anionic conductance in PC12 cells, an effect which was completely blocked by NPPB, a chloride channel inhibitor.

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This study was aimed at understanding the effects of histone modifications on recurrence-free survival (RFS) after esophagectomy in esophageal squamous cell carcinoma (ESCC). The acetylation of histone H3 lysine (H3K9Ac), histone H3 lysine 18 (H3K18Ac), and histone H4 lysine 12 (H4K12Ac), and the dimethylation of histone H3 lysine 9 (H3K9diMe) and histone H4 arginine 3 (H4R3diMe) were analyzed by immunohistochemistry in 237 ESCCs. The K-means clustering algorithm was used to identify unique patterns of histone modifications.

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Article Synopsis
  • The study aimed to find epigenetic markers in plasma that could help detect colorectal cancer at an early stage.
  • Researchers analyzed the methylation patterns of 10 genes in tissue and plasma samples from patients with colorectal cancer and healthy individuals, using a method called methylation-specific PCR.
  • The findings suggested that specific genes (APC, MGMT, RASSF2A, and Wif-1) could serve as effective biomarkers, showing high sensitivity (86.5%) and specificity (92.1%) for early detection of the disease in plasma samples.
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Long-lived people may have a unique genetic makeup that makes them more resistant than the general population to prevalent age-related diseases; however, not much is known about genes involved in the longevity. To identify susceptibility variants controlling longevity, we performed a high-throughput candidate gene study using 137 Koreans over 90 yr old and 213 young healthy Koreans. We evaluated 463 informative markers located in 176 candidate genes mostly for diabetes mellitus, cardiovascular disease and cancer under five genetic models.

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Tumor-associated microtubule-associated protein (TMAP), also known as cytoskeleton associated protein 2 (CKAP2), has been recently shown to be involved in the assembly and maintenance of mitotic spindle and also plays an essential role in maintaining the fidelity of chromosome segregation during mitosis. We have previously reported that TMAP is phosphorylated at multiple residues specifically during mitosis, and characterized the mechanism and functional importance of phosphorylation at one of the mitosis-specific phosphorylation residues (i.e.

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During mitosis, establishment of structurally and functionally sound bipolar spindles is necessary for maintaining the fidelity of chromosome segregation. Tumor-associated microtubule-associated protein (TMAP), also known as cytoskeleton-associated protein 2 (CKAP2), is a mitotic spindle-associated protein whose level is frequently up-regulated in various malignancies. Previous reports have suggested that TMAP is a potential regulator of mitotic spindle assembly and dynamics and that it is required for chromosome segregation to occur properly.

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Polo-like kinase 1 (Plk1) plays a pivotal role in the regulation of cellular proliferation. Plk1 is overexpressed in approximately 80% of human tumors of diverse origins, and overexpression of Plk1 promotes neoplastic transformation of human cells. A growing body of evidence suggests that deregulation of Plk1 closely correlates with prognosis of various cancers in humans.

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