Sang-Han Lee

Elevated c-Src and c-Yes expression in malignant skin cancers

AbstractsBackgroundSrc family kinases (SFKs) play an important role in cancer proliferation, survival, motility, invasiveness, metastasis, and angiogenesis. Among the SFKs, c-Src and c-Yes are particularly over-expressed or hyper-activated in many human epithelial cancers. However, only a few studies have attempted to define the expression and role of c-Src and c-Yes in cutaneous carcinomas.ObjectivesTo investigate the expression of c-Src and c-Yes in cutaneous carcinomas to include malignant melanoma (MM), squamous cell carcinoma (SCC) and basal cell carcinoma (BCC).MethodsWe examined 6 normal skin tissues and 18 malignant skin tumor tissues using western blotting for the expression of c-Src and c-Yes. In another set, 16 specimens of MM, 16 SCCs and 16 BCCs were analyzed for the expression of c-Src and c-Yes using immunohistochemical staining.ResultsWestern blotting showed that c-Src was expressed in all malignant skin tumors, but not in normal skin, while c-Yes was expressed in MM and SCC, but not in BCC and normal skin. Immunohistochemical staining results of c-Src and c-Yes in MM, SCC, and BCC mirrored those of the western blot analysis.Conclusionsc-Src, rather than c-Yes, plays a key role in the proliferation and progression of malignant skin cancers.

Evaluation of Peptide Nucleic Acid Probe-based Real-time PCR for Detection of Mycobacterium tuberculosis Complex and Nontuberculous Mycobacteria in Respiratory Specimens

Background A peptide nucleic acid (PNA) probe-based real-time PCR (PNAqPCR™ TB/NTM detection kit; PANAGENE, Korea) assay has been recently developed for the simultaneous detection of Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM) in clinical specimens. The study was aimed at evaluation of the performance of PNA probe-based real-time PCR in respiratory specimens. Methods To evaluate potential cross-reactivity, the extracted DNA specimens from Mycobacterium species and non-mycobacterial species were tested using PNA probe-based real-time PCR assay. A total of 531 respiratory specimens (482 sputum specimens and 49 bronchoalveolar washing fluid specimens) were collected from 230 patients in July and August, 2011. All specimens were analyzed for the detection of mycobacteria by direct smear examination, mycobacterial culture, and PNA probe-based real-time PCR assay. Results In cross-reactivity tests, no false-positive or false-negative results were evident. When the culture method was used as the gold standard test for comparison, PNA probe-based real-time PCR assay for detection of MTBC had a sensitivity and specificity of 96.7% (58/60) and 99.6% (469/471), respectively. Assuming the combination of culture and clinical diagnosis as the standard, the sensitivity and specificity of the new real-time PCR assay for detection of MTBC were 90.6% (58/64) and 99.6% (465/467), respectively. The new real-time PCR for the detection of NTM had a sensitivity and specificity of 69.0% (29/42) and 100% (489/489), respectively. Conclusions The new real-time PCR assay may be useful for the detection of MTBC in respiratory specimens and for discrimination of NTM from MTBC.

Evaluation of a new immunochromatographic assay kit for the rapid detection of norovirus in fecal specimens.

Rapid and accurate detection of norovirus is essential for the prevention and control of norovirus outbreaks. This study compared the effectiveness of a new immunochromatographic assay kit (SD BIOLINE Norovirus; Standard Diagnostics, Korea) and real-time reverse transcription-PCR (RT-PCR) for detecting norovirus in fecal specimens. Compared with real-time RT-PCR, the new assay had sensitivity, specificity, positive predictive value, and negative predictive value of 76.5% (52/68), 99.7% (342/343), 98.1% (52/53), and 95.5% (342/358), respectively. The sensitivity of the assay was 81.8% (18/22) for GII.3 and 75.7% (28/37) for GII.4. None of the 38 enteric virus-positive specimens (3 for astrovirus, 5 for enteric adenovirus, and 30 for rotavirus) tested positive in the cross-reactivity test performed by using this assay. The new immunochromatographic assay may be a useful screening tool for the rapid detection of norovirus in sporadic and outbreak cases; however, negative results may require confirmatory assays of greater sensitivity.

Suppression of human prostate cancer PC-3 cell growth by N-acetylcysteine involves over-expression of Cyr61

N-Acetylcysteine (NAC), sulfidryl-containing thiol antioxidant, has been heralded as chemopreventive agent, generally because of its ability to scavenge free radicals. It also suppresses the proliferation of many cancer cells; however, the antiproliferative mechanism(s) remain to be fully elucidated. In this study, we investigated a growth-suppressive mechanism of NAC action in androgen-independent prostate carcinoma PC-3 cells. NAC (≥ 1mM) inhibited the proliferation of PC-3 cells in a dose- and time-dependent manner. Moreover, NAC treatment suppressed the activation of NF-κB induced by IKK-β as detected by the NF-κB reporter gene assay. NAC exerted a biphasic effect on the intracellular ROS levels depending on incubation time; the antioxidant effect was seen within 2h after NAC treatment, however, a pro-oxidant effect was evident after 48 h treatment. In addition to these effects, NAC treatment elicited a dose- and time-dependent increase in the Cyr61 expression that was accompanied by an increase in its mRNA and blocked by cycloheximide pretreatment. Importantly, NAC treatment caused an early but transient activation of Akt and Erk1/2. The NAC-induced increase in Cyr61 protein levels was suppressed by the PI3K inhibitor (Ly294002) and, to a lesser extent, MEK/Erk1/2 inhibitor (PD98059). Taken together, our data suggest that the antiproliferative effect of NAC is partially mediated by intracellular ROS production, the inhibition of NF-κB activity, and the activation of PI3K- and/or MEK/Erk-related intracellular signaling pathways, which lead to up-regulation of Cyr61 expression.

House Dust Mite Allergens in Domestic Homes in Cheonan, Korea

House dust mites produce inhalant allergens of importance to allergic patients. We measured the major group 1 allergens, Der p 1 and Der f 1, from the house dust mites Dermatophagoides pteronyssinus and Dermatophagoides farina, respectively in 100 randomly selected domestic homes from Cheonan, Korea. Dust samples were collected by vacuuming from the living room floor and 1 mattress in each home. Der p 1 and Der f 1 were measured by double monoclonal ELISA. Der p 1 levels were very low, with geometric mean levels for floors and mattresses being 0.11 microgram/g (range: 0.01-4.05) and 0.14 microgram/g (range: 0.01-30.0), respectively. Corresponding levels of Der f 1 were higher, 7.46 microgram/g (range: 0.01-262.9) and 10.2 microgram/g (range: 0.01-230.9) for floors and mattresses, respectively. D. farinae appears to be the dominant house dust mite in Cheonan.

Chemokine Receptor CCR3 Expression in Malignant Cutaneous Tumors

BACKGROUND Chemokines and their receptors are important players in tumorigenesis by facilitating tumor proliferation and metastasis. Little is known about the possible function of chemokine receptors in relation to the development and progression of malignant cutaneous tumors. OBJECTIVE The aim of this study was to determine the chemokine receptor CCR3 expression pattern and the protein expression level in selected malignant cutaneous tumors. METHODS Four types of cell lines (G361, A431, SK-MEL-2, SK-MEL-24) were analyzed, using Western blotting, for the expression of CCR3 protein. Immunohistochemical staining for CCR3 was done on 36 skin cancer tissue samples that included 16 squamous cell carcinomas (SCCs), 16 basal cell carcinomas (BCCs), 16 malignant melanomas (MMs) and 6 normal tissue samples. RESULTS Western blot analysis showed that CCR3 protein was more expressed in the MM cell lines (G361, SK-MEL-2,SK-MEL-24) than that in the SCC cell line (A431), and the immunohistochemical analysis showed that CCR3 protein was overexpressed in MM and SCC, it was mildly expressed in BCC and it was hardly expressed in normal tissue. CONCLUSION This study demonstrated via immunochemistry that CCR3 was more expressed in MM, followed by SCC and BCC. The existence of CCR3 protein may enhance the tumorigenic potential of malignant cutaneous tumors.

Abstract 3460: Reactive oxygen species generated by cadmium play a role in the upregulation of aldo-keto reductase 1C3 in RPMI 2630 nasal carcinoma cells

Cadmium (Cd) is a carcinogenic metal which induces oxidative stress through the generation of reactive oxygen species (ROS). Therefore, the ability of cells to up-regulate their antioxidant enzymes is fundamental in the protection of cells and tissues from oxidative damage. In probing the possible survival mechanism of cancer cells to Cd-induced oxidative stress, we examined the ability of Cd to regulate the level of aldo-keto reductase 1C3 (AKR1C3), which has an anti-oxidative role that catalyzes the reductive detoxification of reactive aldehydes and ketones. Exposure of cells to Cd induced a dose- and time-dependent increase in the AKR1C3 expression in the RPMI 2640 nasal septum carcinoma cells, and this up-regulation was blocked by the free radical scavenger N-acetylcysteine (NAC). Additionally, we confirmed that Cd triggered a rapid increase in the intracellular ROS levels, and this increase was inhibited by pretreatment with NAC, which suggests that the up-regulation of AKR1C3 expression involves ROS signaling. Furthermore, pretreatment of cells with LY294002, a pharmacologic inhibitor of phosphatidylinositol-3-kinase (PI3K), suppressed the Cd-augmented AKR1C3 expression; however, inhibition of PKC or MEK1/2 signaling with Go6976 or PD98059, respectively, did not alter Cd-induced AKR1C3 expression. Collectively, these data suggest that Cd can modulate the expression of the AKR1C3 by activation of PI3K via the generation of ROS in RPMI2640 cells, which would contribute to adaptive response to oxidative stress. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3460.