Yong Hee Lee

Negative Regulation of MEKK1-induced Signaling by Glutathione S-Transferase Mu

Mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase 1 (MEKK1) is an important component in the stress-activated protein kinase pathway. Glutathione S-transferase Mu 1-1 (GST M1-1) has now been shown to inhibit the stimulation of MEKK1 activity induced by cellular stresses such as UV and hydrogen peroxide. GST M1-1 inhibited MEKK1 activation in a manner independent of its glutathione-conjugating catalytic activity. In vitro binding and kinase assays revealed that GST M1-1 directly bound MEKK1 and inhibited its kinase activity. Co-immunoprecipitation analysis showed a physical association between endogenous GST M1-1 and endogenous MEKK1 in L929 cells. Overexpressed GST M1-1 interfered with the binding of MEKK1 to SEK1 in transfected HEK293 cells. Furthermore, GST M1-1 suppressed MEKK1-mediated apoptosis. Taken together, our results suggest that GST M1-1 functions as a negative regulator of MEKK1.

Identification of a novel antiapoptotic protein that antagonizes ASK1 and CAD activities

Diverse stimuli initiate the activation of apoptotic signaling pathways that often causes nuclear DNA fragmentation. Here, we report a new antiapoptotic protein, a caspase-activated DNase (CAD) inhibitor that interacts with ASK1 (CIIA). CIIA, by binding to apoptosis signal-regulating kinase 1 (ASK1), inhibits oligomerization-induced ASK1 activation. CIIA also associates with CAD and inhibits the nuclease activity of CAD without affecting caspase-3–mediated ICAD cleavage. Overexpressed CIIA reduces H2O2- and tumor necrosis factor-α–induced apoptosis. CIIA antisense oligonucleotides, which abolish expression of endogenous CIIA in murine L929 cells, block the inhibitory effect of CIIA on ASK1 activation, deoxyribonucleic acid fragmentation, and apoptosis. These findings suggest that CIIA is an endogenous antagonist of both ASK1- and CAD-mediated signaling.

Unilateral Breast Edema: Spectrum of Etiologies and Imaging Appearances

Breast edema is defined as a mammographic pattern of skin thickening, increased parenchymal density, and interstitial marking. It can be caused by benign or malignant diseases, as a result of a tumor in the dermal lymphatics of the breast, lymphatic congestion caused by breast, lymphatic drainage obstruction, or by congestive heart failure. Here we describe several conditions, that cause unilateral breast edema with the aim of familiarizing radiologists with these disease entities.

Prostatic metastasis of large cell neuroendocrine carcinoma of the lung

Large cell neuroendocrine carcinoma (LCNEC) of the lung is a rare and aggressive tumour with a poor prognosis. Lung cancer metastases to the prostate are also uncommon, and are usually found incidentally during autopsy. Most reported primary lung cancers with prostatic metastases are small cell carcinomas, and prostatic metastases from LCNEC of the lung have not been reported previously. This case report describes a 70‐year‐old man with LCNEC of the lung and metastases in the prostate, brain, bone, liver and lymph nodes.

Medullary carcinoma of the breast: Imaging findings characteristics vs histologic classification

It is well known that the medullary carcinoma of the breast is one of the special types of breast carcinoma with a good prognosis. At present, the medullaη carcinoma of the breast is subclassified into 3 types: typical med비laη, atypical med버laπ and nonmed띠laπ carcinoma. Among them, the former has the best prognosis . We reviewed the film mammographic and ultrasonomammographic findings of 13 patients according to the reevaluated histopathologic diagnosis Typical medullary carcinoma shows a well circumscribed mass with sUITounding halo on film mammogram, and well defined mass with central intermediate echogenicity and peripher외 low echogenicity and posterior acoustic enhancement on ultrasonomammogram. Atypical med띠laη carcinoma shows relatively well circumscribed mass with partial marginal obliteration on film mammogram, and irregular bordered mass with inhomogeneous echogenicity due to focal necrosis in the mass and associated findings of thick boundaη, asymetric띠 lateral shadowing on ultrasonomammogram. Nonmedullarγ carcinoma shows lobulated mass with sur rounding parenchym따 distortion and skin thickening on film mammogram , and relatively well defined lobulating mass with surrounding parenchymal distortion and marked heterogeneous internal echogenicity on ultrasonomammogram. Therefore , differentiation between typical med버laη carcinoma with good prognosis and atypical med띠aη or nonmedullary carcinoma with poor prognosis, may be possible by various diagnostic imaging modalities preoperatively. But, further collective study shall be needed in near future.