Hugh Chul Kim

Selective Induction of Apoptosis with Proton Pump Inhibitor in Gastric Cancer Cells

Purpose: To survive in an ischemic microenvironment with a lower extracellular pH, ability to up-regulate proton extrusion is critical for cancer cell survival. Gastric H+/K+-ATPase exchanges luminal K+ for cytoplasmic H+ and is the enzyme primarily responsible for gastric acidification. On the basis of the fact that blocking the clearance of acidic metabolites are known to induce the cell death, we hypothesized that pantoprazole (PPZ), one of gastric H+/K+-ATPase inhibitors used frequently to treat acid-related diseases, could inhibit growth of tumor cells. Experimental Design: Genomic DNA fragmentation, terminal deoxynucleotidyl transferase (Tdt)-mediated nick end labeling assay, and annexin V staining were performed to detect PPZ-induced apoptosis. Mitogen-activated protein kinase activation and heat shock proteins expression were determined by immunoblot with specific antibodies. The antitumor effect of PPZ was evaluated in vivo by a xenograft model of nude mice. Results: After PPZ treatment, apoptotic cell death was seen selectively in cancer cells and was accompanied with extracellular signal-regulated kinase deactivation. By contrast, normal gastric mucosal cells showed the resistance to PPZ-induced apoptosis through the overexpression of antiapoptotic regulators including HSP70 and HSP27. In a xenograft model of nude mice, administration of PPZ significantly inhibited tumorigenesis and induced large-scale apoptosis of tumor cells. Conclusions: PPZ selectively induced in vivo and in vitro apoptotic cell death in gastric cancer, suggesting that proton pump inhibitors could be used for selective anticancer effects.

Isolation of mesenchymal stem cells from cryopreserved human umbilical cord blood

Umbilical cord blood (UCB) is well known to be a rich source of hematopoietic stem cells with practical and ethical advantages. Because mesenchymal stem cells (MSCs) from bone marrow have been regarded as good materials for cell/gene therapy as well as for tissue engineering because of their multidifferentiation potential, a number of trials have been undertaken to isolate MSCs from UCB. However, the results have been controversial, and little has become known about the effect of cryopreservation on the isolation of these stem cells. In this study, we examined the ability of cryopreserved UCB-derived cells to produce MSCs.Various culture conditions, including the seeding concentrations of cells and the media used, were investigated. We were able to obtain adherent cell populations after 3 to 5 weeks in our culture conditions from UCB-derived mononuclear cell fractions that had undergone cryopreservation for 0.1 to 5 years.These cells exhibited a fibroblast-like morphology and typical mesenchymal-like immunophenotypes.The results indicate that cryopreserved human UCB fractions can be used as an alternative source of MSCs for experimental and clinical applications as well as for tissue engineering.

Vascular endothelial growth factor in the serum of patients with non-small cell lung cancer: correlation with platelet and leukocyte counts.

BACKGROUND Vascular endothelial growth factor (VEGF) is a potent angiogenic peptide expressed in a wide variety of tumors, and it stimulates angiogenesis and increases vascular permeability. Increased expression of VEGF may be associated with advanced stage and poor prognosis in patients with non-small cell lung cancer (NSCLC). METHODS Using enzyme-linked immunosorbent assay, the levels of VEGF were determined in serum from 41 patients with untreated NSCLC (Stage: IIB, 3; IIIA, 6; IIIB, 17; IV, 15; HISTOLOGY squamous cell carcinoma, 18; adenocarcinoma. 14; undetermined, 9). RESULTS The median VEGF level was 312 pg/ml, ranging from 70 to 1440 pg/ml. Patients were divided into high VEGF (>312 pg/ml) and low VEGF (< or =312 pg/ml) groups using the median value as a cut-off. There were no significant associations between the serum VEGF levels and various clinicopathologic characteristics including age, gender, histologic type, stage and treatment. A significant positive correlation was found between serum VEGF levels and platelet counts (r=0.495; P=0.001). In addition, serum VEGF levels also correlated with leukocyte counts (r=0.478; P=0.002). In seven patients with measurement of follow-up serum VEGF levels at the end of treatment (chemotherapy and/or radiotherapy), the median serum VEGF level significantly decreased after the treatment (416 pg/ml; range, 96-812 pg/ml vs. 185 pg/ml; range, 49-487 pg/ml; P=0.028). However, the median platelet count (317,000/microl; range, 190,000-395,000/microl vs. 246,000/microl; range, 72,000-271,000/microl; P=0.028) and leukocyte count (10,000/microl; range, 8700-17,200/microl vs. 5100/microl; range, 3900-9500/microl; P=0.018) also decreased after the treatment. There was no statistically significant difference in the median survival of the patients between high VEGF group and low VEGF group (8 months vs. 9 months, P=0.647). CONCLUSIONS Although serum VEGF level was significantly associated with platelet and leukocyte counts in NSCLC patients, it did not correlate with tumor burden and prognosis of the patients.

Ramosetron for the Prevention of Cisplatin-Induced Acute Emesis: A Prospective Randomized Comparison with Granisetron

Control of nausea and vomiting is very important in determining patient compliance with cisplatin chemotherapy. A multicentre, randomized, single-blind study was conducted to compare the tolerability and efficacy of ramosetron with those of granisetron over 24 h following cisplatin administration to cancer patients. In eight study centres, a total of 194 adult patients were randomly assigned to receive either intravenous ramosetron 0.3 mg or intravenous granisetron 3.0 mg. The anti-emetic effect of ramosetron determined from the no-vomiting rate lasted longer, but there was no significant difference in the number of acute vomiting episodes or the severity of nausea between the two groups. In the tolerability evaluation, there were no statistically significant differences between the two groups, except for a higher incidence of dull headache in the granisetron group. Ramosetron and granisetron appear to have equivalent efficacy and tolerability profiles, but the effects of ramosetron on the prevention of acute vomiting in patients undergoing cisplatin chemotherapy were longer lasting.

Low expression of Bax predicts poor prognosis in patients with locally advanced esophageal cancer treated with definitive chemoradiotherapy.

Purpose: The present study evaluated the prognostic significance of apoptosis-related proteins, p53, Bcl-2, Bax, and galectin-3 in patients with locally advanced esophageal cancer treated with definitive chemoradiotherapy. Experimental Design: A total of 63 patients with locally advanced esophageal cancer (squamous cell carcinoma: 62; adenocarcinoma: 1; stages II-IV) were treated with definitive chemoradiotherapy using 5-fluorouracil and cisplatin combined with radiotherapy. Pretreatment tumor biopsy specimens were analyzed for p53, Bcl-2, Bax, and galectin-3 expression by immunohistochemistry. Results: High expression of Bax, p53, Bcl-2, and galectin-3 was observed in 67%, 47%, 24%, and 29% of patients, respectively. The median overall survival (OS) of total patients was 14 months with 16% of 3-year OS. High expression of p53, Bcl-2, and galectin-3 did not show correlation with clinicopathologic characteristics, including patient outcome. Low expression of Bax was significantly correlated with lack of clinical complete response (P = 0.023). Low expression of Bax was also associated with poor OS (median, 8 months versus 16 months; P = 0.0008) in univariate analysis. In multivariate analysis, low expression of Bax was the most significant independent predictor of poor OS (P = 0.009), followed by low dose intensity of cisplatin and lack of clinical complete response. Conclusions: Low expression of Bax was significantly associated with the poor survival of patients with locally advanced esophageal cancer treated with chemoradiotherapy using 5-fluorouracil and cisplatin. Immunohistochemical staining for Bax with a pretreatment biopsy specimen might be useful to select the optimal treatment options for these patients.

Endothelial progenitor cell differentiation using cryopreserved, umbilical cord blood-derived mononuclear cells

AbstractAim:To investigate the endothelial differentiation potentiality of umbilical cord blood (UCB), we induced the differentiation of endothelial progenitor cells (EPC) from cryopreserved UCB-derived mononuclear cells (MNC).Methods:MNC from cryopreserved UCB and peripheral blood (PB) were cultured in M199 medium with endothelial cell growth supplements for 14 d. EPC were characterized by RT-PCR, flow cytometry, and immunocytochemistry analysis. The proliferation of differentiated EPC was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay, and vascular endothelial growth factor (VEGF) concentration was measured using an ELIS A kit. Characteristics of UCB-derived EPC were compared with those of PB-derived EPC.Results:A number of round-shaped cells were loosely attached to the bottom after 24 h culture, and numerous spindle-shaped cells began to appear from the round-shaped ones on d 7. Those cells expressed endothelial markers such as, Flt-1/VEGFR-1, ecNOS, VE-cadherin, von Willebrand factor, and secreted VEGF. The patterns of endothelial markers of EPC from PB and UCB did not show striking differences. The results of the proliferation and secretion of VEGF were also similar.Conclusion:We successfully cultured UCB cells stored at -196°C into cells with the quality of endothelial cells. Those EPC could be used for angiogenic therapeutics by activating adjacent endothelial cells and enhancing angiogenesis.

Hepatic differentiation of cord blood-derived multipotent progenitor cells (MPCs) in vitro.

Umbilical cord blood (UCB) is a rich source of hematopoietic stem cells that possesses practical and ethical advantages. We previously reported a novel UCB‐derived adult stem cells which we termed umbilical cord blood‐derived multipotent progenitor cells’ (MPCs). MPCs were capable of differentiating into functional neuronal cells. Under appropriate conditions lasting several days or weeks, we now show that the MPCs differentiate into hepatocyte‐like cells in vitro; their properties were verified using reverse transcription‐polymerase chain reaction (RT‐PCR), Western blot, immunofluorescence, periodic acid‐Schiff (PAS) staining of accumulated glycogen and an enzyme‐linked immunosorbent assay (ELISA). We also found that hepatic differentiated cells expressed hepatocyte specific markers, such as albumin, hepatocyte nuclear factor (HNF)‐1α, HNF4, cytokeratin (CK)‐8, CK‐18, tyrosine amino transferase (TAT), and CYP2B6. Moreover, albumin was secreted, which suggests that MPCs from UCB possess multi‐differentiation potential and have the capacity to differentiate into functional cells of hepatic lineage in vitro.

Detection of Transforming Growth Factor-α in the Serum of Gastric Carcinoma Patients

Transforming growth factor-α (TGF-α) is a ligand for epidermal growth factor receptor (EGFR) and it is overexpressed in various malignancies including lung, esophageal, colorectal, ovarian and gastric carcinomas. In patients with gastric carcinoma, its overexpression may be associated with advanced stage or poor prognosis. We have recently demonstrated that the mean serum level for EGFR in gastric carcinoma patients was significantly elevated compared with that of healthy controls. Using the enzyme-linked immunosorbent assay, the levels of TGF-α were determined in serum from 40 patients with gastric carcinoma (5 patients with stage I, 2 stage II, 4 stage III, and 29 stage IV patients) and 33 healthy controls. The mean serum level for TGF-α in the gastric carcinoma patients was significantly elevated as compared with that of healthy controls (104 ± 235 vs. 22 ± 16 pg/ml; p = 0.03). Eleven patients with gastric carcinoma (27.5%) showed elevated serum TGF-α levels above the cutoff value of 54 pg/ml (defined as 2 standard deviations above the mean of the control group). No significant association was noted between the positivity of TGF-α and clinicopathologic characteristics including gender, age and stage. However, poorly differentiated adenocarcinoma showed a higher positivity of serum TGF-α (43.8%) compared with other histologic types, which was marginally significant (p = 0.06). These results suggest that serum TGF-α could be useful as a tumor marker of gastric carcinoma for predicting prognosis and follow-up after surgery in patients whose initial serum TGF-α levels are elevated.

Imaging of malignant lymphomas with F-18 FDG coincidence detection positron emission tomography.

Purpose The authors evaluated the utility of F-18 fluorodeoxyglucose (FDG) coincidence detection (CoDe) positron emission tomography (PET) for staging, post-treatment evaluation, and follow-up assessment of patients with malignant lymphomas. Materials and Methods Fifty-eight patients with histologically proved malignant lymphomas (4 Hodgkin’s disease, 54 non-Hodgkin’s lymphoma) underwent CoDe PET using F-18 FDG. CoDe PET was performed using a dual-head gamma camera equipped with coincidence detection circuitry. Of the 87 CoDe PET studies, 26 were performed for staging, 38 for post-treatment evaluation, and 23 for follow-up evaluation of recurrence. The entire trunk, from the cervical to the inguinal regions, or selected regions were scanned with the patient in the supine position. No attenuation correction was made and reconstruction was performed using filtered backprojection rather than iterative reconstruction. CoDe PET findings were compared with corresponding results of computed tomographic (CT) and magnetic resonance imaging (MRI), tissue biopsy, or clinical follow-up. Results For staging, 52 sites were positive on CoDe PET or CT–MRI. CoDe PET detected 49 sites (94%), and CT–MRI showed 47 sites (90%). CoDe PET detected five more lymphomatous lesions and missed three lesions. For post-treatment evaluation, CoDe PET showed a positive predictive value of 100% and a negative predictive value of 83%, but the validated cases numbered only 11. For follow-up for recurrence, CoDe PET had a negative predictive value of 90%, but frequent false-positive findings were noted in the head and neck region as a result of underlying inflammatory changes. Conclusions For staging, FDG CoDe PET alone without attenuation correction is not sensitive enough to be used as an independent imaging method, especially for small abdominal lesions. However, it appears to be an accurate method for assessing residual disease and for patient follow-up.

A case of chronic myelogenous leukemia with e8a2 fusion transcript

The Philadelphia chromosome and its corresponding fusion gene, BCR-ABL, is one of the best-known genetic abnormalities in hematological malignancies. Major BCR-ABL translocation is much more common in chronic myelogenous leukemia (CML) and minor BCR-ABL in acute lymphoblastic leukemia. We experienced an extraordinarily rare case of CML with an e8a2 variant. An unusual band, other than the common transcripts, was observed in reverse transcription-polymerase chain reaction (RT-PCR) for the BCR-ABL gene rearrangement. Sequence analysis of the PCR product revealed an 1172-bp e8a2 fusion with a 14-bp insertion of ABL intron Ia. The patient achieved a complete hematological response 3 months after imatinib treatment. It is necessary to keep in mind that an unexpected band revealed with RT-PCR may mean the presence of unusual fusion gene.