Kwan-Sung Lee

Brain-derived neurotrophic factor stimulates the neural differentiation of human umbilical cord blood-derived mesenchymal stem cells and survival of differentiated cells through MAPK/ERK and PI3K/Akt-dependent signaling pathways

Brain‐derived neurotrophic factor (BDNF) plays an important role in the differentiation, development, and survival of neural stem cells. In this study, we analyzed its effects on the stimulation of human umbilical cord blood‐derived mesenchymal stem cells in terms of their potential to differentiate into neuron‐like cells, their survival characteristics, and the molecular mechanisms involved. The treatment of cells with neural induction medium (NIM) and BDNF generated more cells that were neuron‐like and produced stronger expression of neural‐lineage markers than cells treated with NIM and without BDNF. Raf‐1 and ERK phosphorylation and p35 expression levels increased significantly in cells treated with both NIM and BDNF. This treatment also effectively blocked cell death following neural induction and increased Akt phosphorylation and Bcl2 expression compared with cells treated with NIM without BDNF. Inhibition of ERKs inhibited the BDNF‐stimulated up‐regulation of p35 and Bcl2. In addition, the inhibition of PI3K abrogated Akt phosphorylation and Bcl2 expression, but not p35 expression. Thus, MAPK/ERK‐dependent p35 up‐regulation and MAPK/ERK‐dependent and PI3K/Akt‐dependent Bcl2 up‐regulation contribute to BDNF‐stimulated neural differentiation and to the survival of differentiated cells.

Antiproliferative and antiviral mechanisms of ursolic acid and dexamethasone in cervical carcinoma cell lines

The chemical structure of ursolic acid is very similar to that of dexamethasone, a synthetic glucocorticoid. Herein, we investigated the antiproliferative and antiviral effects of ursolic acid and dexamethasone in human papillomavirus (HPV)-associated cervical cancer cells. We performed 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazonium bromide assay to measure antiproliferative activity, and also characterized apoptosis by DNA fragmentation, 4′-6-diamidino-2-phenylindole (DAPI) staining, and flow cytometry (FACS) analysis. We investigated apoptosis-related proteins using western blots. After in vitro treatment, we used reverse transcription–polymerase chain reaction for the expression of the HPV E6/E7 gene to observe the antiviral effects. Ursolic acid suppressed the growth of HPV-positive cervical carcinoma cells (HeLa, CaSki, and SiHa) in a dose- and time-dependent manner, but not the HPV-negative cervical cancer cell line (C33A). Ursolic acid-treated HeLa cells showed typical apoptosis characteristics in DNA fragmentation, DAPI staining, and FACS analysis. The expression of Fas protein was induced, and caspase-8, caspase-3, and poly ADP-ribose polymerase (PARP) proteins were cleaved after ursolic acid treatment. HPV-18 E6/E7 gene expression decreased after ursolic acid treatment in HeLa cells, but the levels of p53 and Rb proteins did not change. In contrast, dexamethasone, which has a similar structure, did not inhibit proliferation. Our findings may offer new insight into the mechanism of antiproliferative and antiviral effect of ursolic acid. Also, these results suggest that ursolic acid might be a useful anticancer drug in treatment of HPV-associated cervical neoplasia.

In vivo Tracking of Transplanted Bone Marrow-Derived Mesenchymal Stem Cells in a Murine Model of Stroke by Bioluminescence Imaging

OBJECTIVE This study was designed to validate the cell trafficking efficiency of the in vivo bioluminescence image (BLI) study in the setting of transplantation of the luciferase expressing bone marrow-derived mesenchymal stem cells (BMSC), which were delivered at each different time after transient middle cerebral artery occlusion (MCAO) in a mouse model. METHODS Transplanting donor BMSC were prepared by primary cell culture from transgenic mouse expressing luciferase (LUC). Transient focal infarcts were induced in 4-6-week-old male nude mice. The experiment mice were divided into five groups by the time of MSC transplantation : 1) sham-operation group, 2) 2-h group, 3) 1-day group, 4) 3-day group, and 5) 1- week group. BLI for detection of spatial distribution of transplanted MSC was performed by detecting emitted photons. Migration of the transplanted cells to the infarcted area was confirmed by histological examinations. Differences between groups were evaluated by paired t-test. RESULTS A focal spot of bioluminescence was observed at the injection site on the next day after transplantation by signal intensity of bioluminescence. After 4 weeks, the mean signal intensities of 2-h, 1-day, 3-day, and 1-week group were 2.6×10(7) ± 7.4×10(6), 6.1×10(6) ± 1.2×10(6), 1.7×10(6) ± 4.4×10(5), and 8.9×10(6) ± 9.5×10(5), respectively. The 2-h group showed significantly higher signal intensity (p < 0.01). The engrafted BMSC showed around the infarct border zones on immunohistochemical examination. The counts of LUC-positive cells revealed the highest number in the 2-h group, in agreement with the results of BLI experiments (p < 0.01). CONCLUSION In this study, the results suggested that the transplanted BMSC migrated to the infarct border zone in BLI study and the higher signal intensity of LUC-positive cells seen in 2 hrs after MSC transplantation in MCAO mouse model. In addition, noninvasive imaging in real time is an ideal method for tracking stem cell transplantation. This method can be widely applied to various research fields of cell transplantation therapy.

Repeat Operations in Pediatric Patients with Recurrent Craniopharyngiomas

Background: Controversy continues over the optimal management of recurrent craniopharyngiomas. Our strategy for approaching repeatedly recurrent craniopharyngiomas in pediatric patients has been to decompress vital structures and relieve the symptoms as early as possible. The purpose of this study was to present our experiences of repeatedly recurrent craniopharyngiomas and the pattern of failure associated with treatment. Methods: A retrospective review was conducted on 7 pediatric patients who underwent resection >2 times in a single institution between 1990 and 2004. Resections were performed 3–8 times for each patient. Variables including tumor size, consistency and location, extent of resection, adjuvant therapy and morbidity were evaluated. Results: Thirty-two operations were performed in 7 pediatric patients. Total resection was not achieved by the third surgery and thereafter, and the interval between each surgery became shorter. Appetite disorders, neurocognitive disorders and behavioral disorders occurred following repeat surgeries. Conclusion: Repeat operations are associated with a high failure rate of tumor control, even though they can help relieve neurologic symptoms. It is suggested that the number of repeat operations should be limited.

Pituitary Apoplexy Producing Internal Carotid Artery Compression: A Case Report

We report a case of pituitary apoplexy resulting in right internal carotid artery occlusion accompanied by hemiplegia and lethargy. A 43-yr-old man presented with a sudden onset of severe headache, visual disturbance and left hemiplegia. Investigations revealed a nodular mass, located in the sella and suprasellar portion and accompanied by compression of the optic chiasm. The mass compressed the bilateral cavernous sinuses, resulting in the obliteration of the cavernous portion of the right internal carotid artery. A border zone infarct in the right fronto-parietal region was found. Transsphenoidal tumor decompression following conservative therapy with fluid replacement and steroids was performed. Pathological examination revealed an almost completely infarcted pituitary adenoma. The patients vision improved immediately after the decompression, and the motor weakness improved to grade IV+ within six months after the operation. Pituitary apoplexy resulting in internal carotid artery occlusion is rare. However, clinicians should be aware of the possibility and the appropriate management of such an occurrence.

Retrospective multicenter study of a clinicopathologic analysis of pseudomyxoma peritonei associated with ovarian tumors (KGOG 3005)

The purpose of this study is to assess clinicopathologic features of pseudomyxoma peritonei (PMP) that has ovarian pathology and its relationship with the prognosis. From 1995 to 2004, the clinical records and follow-up data of 35 patients with PMP, which had primarily originated from the ovary, were collected from 11 institutes of gynecologic oncology in Korea and retrospectively analyzed. All patients had ovarian lesion histologically confirmed with PMP. The mean age at diagnosis was 53.7 years (range: 16–82 years). There were 25 (71.4%) patients with disseminated peritoneal adenomucinosis, 5 (14.3%) with peritoneal mucinous carcinomatosis with intermediate group, and 5 (14.3%) with peritoneal mucinous carcinomatosis. The clinical stages at diagnosis were IA in 2 patients, IIIB in 4, IIIC in 23, IV in 1, and unknown in 5. In preoperative tumor markers, the positive rates were 72% (CA125), 47.4% (CA19-9), and 84.6% (CEA). Thirty-four patients underwent surgical staging or cytoreduction, and then 27 patients (77%) received adjuvant chemotherapy that was given to patients in a nonuniform fashion. The 5-year survival for 35 patients was 87%. Survival rate was significantly lower in patients >50 years of age (P= 0.002). Our data showed that age of the patient is the only significant prognostic factor in PMP that has ovarian lesion.

Temozolomide chemotherapy in patients with recurrent malignant gliomas.

Numerous studies have demonstrated the clinical activity of temozolomide, a second-generation alkylating agent, against malignant brain tumors, however, its activity has not been reported in an Asian population. This study analyzed the efficacy and toxicity of temozolomide in 25 adult patients with recurrent or progressive malignant gliomas after surgery and standard radiation therapy with or without chemotherapy, enrolled in our institution since July 2000. Sixteen patients had glioblastoma multiforme (GBM), six with anaplastic astrocytoma, and three with anaplastic oligodendroglioma. Of the 25 patients, 3 (12%) achieved a complete response (CR), 8 (32%) achieved a partial response (PR), 6 (24%) had stable disease (SD), and 8 (32%) had progressive disease (PD). Two patients achieved a CR, 4 patients achieved a PR, 3 patients had SD and 7 patients had PD in GBM, and 1 patient achieved a CR, 4 patients achieved a PR, 3 patients had SD, 1 patient had PD in the non-GBM patients. Median progression free survival was 8 weeks in GBM and 22 weeks in the non-GBM patients. The median overall survival of each group was 17 weeks and 28 weeks. Temozolomide demonstrated moderate activity in recurrent and progressive malignant gliomas without serious toxicity.

Expression of the CD44 adhesion molecule in primary and metastatic gynecologic malignancies and their cell lines.

CD44 is a cell-surface molecule that has been shown to have several splicing isoforms. In various human tumors, such as primary colon and breast tumors, and their metastases, alterations of CD44 isoform expression have been reported. The present study was performed to investigate CD44 alternative transcript splicing in gynecologic malignancies. We performed reverse transcriptase polymerase chain reaction (RT-PCR) analysis of CD44 splice variant expression on mRNA transcripts from ovarian carcinomas (six primary and 15 metastatic tumors) from 21 patients and from cervical carcinomas (25 primary and two metastatic tumors) from 25 patients. We also performed this analysis on five different ovarian carcinoma cell lines established from ascitic fluid and primary tumors, and two cervical carcinoma cell lines. We included eight normal female genital tissue specimens and one additional placenta specimen in our RT-PCR analysis for comparison with CD44 expression of carcinomas. The CD44H isoform was amplified in all of the specimens. None of eight normal tissue specimens, including myometrium and ovary, expressed CD44R1 transcripts. But the CD44R1 transcript was expressed in 2/6 (33.3%) primary ovarian carcinomas and in 7/15 (46.6%) metastatic ovarian carcinomas. In cervical carcinoma, 13/25 (52.0%) primary tumors and 2/2 (100.0%) metastatic tumors expressed CD44R1. The CD44R1 transcript was expressed increasingly during ovarian and cervical tumor progression (P = 0.026 and P = 0.002, respectively). In conclusion, the frequency of CD44R1 transcript expression increased during ovarian and cervical carcinoma progression, and analysis of CD44 splice variants may be useful in detecting primary and metastatic gynecologic malignancies.

Clinical Analysis of Intracranial Hemangiopericytoma

Objective Intracranial hemangiopericytomas (HPCs) are rare tumors with aggressive behavior, including local recurrence and distant metastasis. We conducted this retrospective study to evaluate the efficacy of grossly total resection and adjuvant radiotherapy (RT) for these tumors. Methods A total of 13 patients treated for intracranial HPC from January 1995 through May 2013 were included in this retrospective study. We analyzed the clinical presentations, radiologic appearances, treatment results, and follow-up outcomes, as well as reviewed other studies. Results The ages of the patients at the time of diagnosis ranged from 26 to 73 years (mean : 48 years). The majority of the patients were male (92.3%), and the majority of the tumors were located in the parasagittal and falx. The ratio of intracranial HPCs to meningiomas was 13 : 598 in same period, or 2.2%. Seven patients (53.8%) had anaplastic HPCs. Nine patients (69.2%) underwent gross total tumor resection in the first operation without mortality. Eleven patients (84.6%) underwent postoperative adjuvant RT. Follow-up period ranged from 13 to 185 months (mean : 54.3 months). The local recurrence rate was 46.2% (6/13), and there were no distant metastases. The 10-year survival rate after initial surgery was 83.9%. The initial mean Karnofsky performance scale (KPS) was 70.8 and the final mean KPS was 64.6. Conclusion Gross total tumor resection upon initial surgery is very important. We believe that adjuvant RT is helpful even with maximal tumor resection. Molecular biologic analyses and chemotherapy studies are required to achieve better outcomes in recurrent intracranial HPCs.

De Novo Aneurysm after Treatment of Glioblastoma

A rare case of spontaneous subarachnoid hemorrhage from newly developed cerebral aneurysm in glioblastoma patient is presented. A 57-year-old man was presented with headache and memory impairment. On the magnetic resonance image and the magnetic resonance angiography, a large enhancing mass was found at right frontal subcortex and intracranial aneurysm was not found. The mass was removed subtotally and revealed as glioblastoma. He took concurrent PCV chemotherapy and radiation therapy, but the mass recurred one month later after radiotherapy. He was then treated with temozolomide for 7 cycles. Three months after the completion of temozolomide therapy, he suffered from a subarachnoid hemorrhage due to a rupture of a small de novo aneurysm at distal anterior cerebral artery. He underwent an aneurysm clipping and discharged without neurologic complication.