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21 result(s) for "Rhim, H. R."
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Effects of exercise on circulating tumor cells among patients with resected stage I-III colon cancer
Physical activity is associated with a lower risk of disease recurrence among colon cancer patients. Circulating tumor cells (CTC) are prognostic of disease recurrence among stage I-III colon cancer patients. The pathways through which physical activity may alter disease outcomes are unknown, but may be mediated by changes in CTCs. Participants included 23 stage I-III colon cancer patients randomized into one of three groups: usual-care control, 150 min∙wk-1 of aerobic exercise (low-dose), and 300 min∙wk-1 of aerobic exercise (high-dose) for six months. CTCs from venous blood were quantified in a blinded fashion using an established microfluidic antibody-mediated capture device. Poisson regression models estimated the logarithmic counts of CTCs. At baseline, 78% (18/23) of patients had ≥1 CTC. At baseline, older age (-0.12±0.06; P = 0.04), lymphovascular invasion (0.63±0.25; P = 0.012), moderate/poor histology (1.09±0.34; P = 0.001), body mass index (0.07±0.02; P = 0.001), visceral adipose tissue (0.08±0.04; P = 0.036), insulin (0.06±0.02; P = 0.011), sICAM-1 (0.04±0.02; P = 0.037), and sVCAM-1 (0.06±0.03; P = 0.045) were associated with CTCs. Over six months, significant decreases in CTCs were observed in the low-dose (-1.34±0.34; P<0.001) and high-dose (-1.18±0.40; P = 0.004) exercise groups, whereas no significant change was observed in the control group (-0.59±0.56; P = 0.292). Over six months, reductions in body mass index (-0.07±0.02; P = 0.007), insulin (-0.08±0.03; P = 0.014), and sICAM-1 (-0.07±0.03; P = 0.005) were associated with reductions in CTCs. The main limitations of this proof-of-concept study are the small sample size, heterogenous population, and per-protocol statistical analysis. Exercise may reduce CTCs among stage I-III colon cancer patients. Changes in host factors correlated with changes in CTCs. Exercise may have a direct effect on CTCs and indirect effects through alterations in host factors. This hypothesis-generating observation derived from a small pilot study warrants further investigation and replication.
Dose–response effects of aerobic exercise on body composition among colon cancer survivors: a randomised controlled trial
Background: Physical activity is associated with a lower risk of disease recurrence among colon cancer survivors. Excess visceral adipose tissue is associated with a higher risk of disease recurrence among colon cancer survivors. The pathways through which physical activity may alter disease outcomes are unknown, but may be mediated by changes in visceral adipose tissue. Methods: Thirty-nine stage I–III colon cancer survivors were randomised to one of three groups: usual-care control, 150 min wk −1 of aerobic exercise (low dose) and 300 min wk −1 of aerobic exercise (high dose) for 6 months. The prespecified key body composition outcome was visceral adipose tissue quantified using dual energy X-ray absorptiometry. Results: Exercise reduced visceral adipose tissue in dose–response fashion ( P trend =0.008). Compared with the control group, the low- and high-dose exercise groups lost 9.5 cm 2 (95% CI: –22.4, 3.5) and 13.6 cm 2 (95% CI: –27.0, –0.1) in visceral adipose tissue, respectively. Each 60 min wk −1 increase in exercise predicted a 2.7 cm 2 (95% CI: –5.4, –0.1) reduction in visceral adipose tissue. Conclusions: Aerobic exercise reduces visceral adipose tissue in dose–response fashion among patients with stage I–III colon cancer. Visceral adipose tissue may be a mechanism through which exercise reduces the risk of disease recurrence among colon cancer survivors.
Activation of EphA receptor tyrosine kinase inhibits the Ras/MAPK pathway
Interactions between Eph receptor tyrosine kinases (RTKs) and membrane-anchored ephrin ligands critically regulate axon pathfinding and development of the cardiovascular system, as well as migration of neural cells. Similar to other RTKs, ligand-activated Eph kinases recruit multiple signalling and adaptor proteins, several of which are involved in growth regulation 1 , 2 . However, in contrast to other RTKs, activation of Eph receptors fails to promote cell proliferation 3 , 4 or to transform rodent fibroblasts 5 , indicating that Eph kinases may initiate signalling pathways that are distinct from those transmitted by other RTKs. Here we show that stimulation of endogenous EphA kinases with ephrin-A1 potently inhibits the Ras/MAPK cascade in a range of cell types, and attenuates activation of mitogen-activated protein kinase (MAPK) by receptors for platelet-derived growth factor (PDGF), epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF). In prostatic epithelial cells and endothelial cells, but not fibroblasts, treatment with ephrin-A1 inhibits cell proliferation. Our results identify EphA kinases as negative regulators of the Ras/MAPK pathway that exert anti-mitogenic functions in a cell-type-specific manner.
APOBEC3A drives deaminase domain-independent chromosomal instability to promote pancreatic cancer metastasis
Despite efforts in understanding its underlying mechanisms, the etiology of chromosomal instability (CIN) remains unclear for many tumor types. Here, we identify CIN initiation as a previously undescribed function for APOBEC3A (A3A), a cytidine deaminase upregulated across cancer types. Using genetic mouse models of pancreatic ductal adenocarcinoma (PDA) and genomics analyses in human tumor cells we show that A3A-induced CIN leads to aggressive tumors characterized by enhanced early dissemination and metastasis in a STING-dependent manner and independently of the canonical deaminase functions of A3A. We show that A3A upregulation recapitulates numerous copy number alterations commonly observed in patients with PDA, including co-deletions in DNA repair pathway genes, which in turn render these tumors susceptible to poly (ADP-ribose) polymerase inhibition. Overall, our results demonstrate that A3A plays an unexpected role in PDA as a specific driver of CIN, with significant effects on disease progression and treatment.
Volumetric feedback ablation of uterine fibroids using magnetic resonance-guided high intensity focused ultrasound therapy
Objective The purpose of this prospective multicenter study was to assess the safety and technical feasibility of volumetric Magnetic Resonance-guided High Intensity Focused Ultrasound (MR-HIFU) ablation for treatment of patients with symptomatic uterine fibroids. Methods Thirty-three patients with 36 fibroids were treated with volumetric MR-HIFU ablation. Treatment capability and technical feasibility were assessed by comparison of the Non-Perfused Volumes (NPVs) with MR thermal dose predicted treatment volumes. Safety was determined by evaluation of complications or adverse events and unintended lesions. Secondary endpoints were pain and discomfort scores, recovery time and length of hospital stay. Results The mean NPV calculated as a percentage of the total fibroid volume was 21.7%. Correlation between the predicted treatment volumes and NPVs was found to be very strong, with a correlation coefficient r of 0.87. All patients tolerated the treatment well and were treated on an outpatient basis. No serious adverse events were reported and recovery time to normal activities was 2.3 ± 1.8 days. Conclusion This prospective multicenter study proved that volumetric MR-HIFU is safe and technically feasible for the treatment of symptomatic uterine fibroids. Key Points • Magnetic-resonance-guided high intensity focused ultrasound allows non-invasive treatment of uterine fibroids. • Volumetric feedback ablation is a novel technology that allows larger treatment volumes • MR-guided ultrasound ablation of uterine fibroids appears safe using volumetric feedback
Combined motor- and somatosensory-evoked potential monitoring for spine and spinal cord surgery: correlation of clinical and neurophysiological data in 85 consecutive procedures
Study design: Prospective study. Objectives: The primary objective of neurophysiological monitoring during surgery is to prevent permanent neurological sequelae. To avoid neurological injury, we applied somatosensory-evoked potentials (SEPs) and/or motor-evoked potentials (MEPs). We evaluated whether the combination of SEP and MEP for spinal surgery may be beneficial. Setting: Asian Medical Center, University of Ulsan College of Medicine, Seoul, Korea. Methods: Combined SEP/MEP monitoring was attempted in 100 consecutive procedures for spinal operations. Trains of transcranial electrical stimulation over the motor cortex were used to elicit MEPs from the muscles of the upper/lower limbs. The tibial and median nerves were stimulated to record SEP. Results: Combined SEP/MEP recording was successfully achieved in 85 of 100 operations. In 61 of 85 operations (71%), SEP and MEP were stable, and all patients remained neurologically intact after surgery. Significant MEP changes were recorded in 20 operations, either combined with ( n =4) or without ( n =16) SEP changes. In 7 of these 20 operations, MEP recovered to some extent after surgical intervention, and these patients showed no neurological changes. In the remaining 13 operations, MEP did not recover and the patients had a transient ( n =4) or a permanent ( n =3) motor deficit. Significant SEP changes with stable MEP were observed in four operations, all of which were not related to postoperative motor deficit. Conclusion: Combined SEP/MEP monitoring provided higher sensitivity and higher positive/negative predictive value than single-modality monitoring techniques. Detection of MEP changes and adjustment of surgical strategy may prevent irreversible pyramidal tract damage.
Expression of dominant negative Jun inhibits elevated AP-1 and NF-κB transactivation and suppresses anchorage independent growth of HPV immortalized human keratinocytes
AP-1 transactivation appears to be required for mouse JB6 cell neoplastic transformation induced by the tumor promoter TPA or epidermal growth factor (EGF). Exposure to AP-1 transrepressing retinoids and glucocorticoids and expression of a dominant negative c-jun (TAM67) blocked tumor promoter-induced AP-1 transactivation and neoplastic transformation. The aim of the present study was to extend the inquiry of the role of AP-1 and other transcription factors to human neoplastic progression. Expression of human papillomavirus (HPV) 16 or 18 E6 and E7 immortalizes human keratinocytes and inhibits serum/calcium-stimulated differentiation. Further transformation by v-fos co-expression renders these keratinocytes tumorigenic in nude mice. We have analysed two series of E6/E7 immortalized human keratinocyte cell lines that show progressing phenotypes ranging from differentiation sensitive to anchorage-independent to tumorigenic in nude mice. We analysed the activities of AP-1 and NF-κB which may `cross-talk'. Both DNA binding and transactivation of AP-1 and NF-κB transcription factors showed elevation in the anchorage-independent (16RH) and tumorigenic (18 v-fos) keratinocyte lines compared to the less progressed but immortalized cell lines. HPV E7 was expressed at a constant level shown by quantitative RT-PCR in both the more and the less progressed lines, indicating that E7 is not the factor limiting this progression. Blocked shift/supershift analysis indicates that Fos family member proteins especially Fra-1 and Fra-2 are related to progression and no changes found in the Jun family member proteins although they are present in the AP-1/DNA binding complex. When a dominant negative mutant c-jun driven by a human keratin 14 promoter was co-transfected with AP-1 or NF-κB reporters, both AP-1 and NF-κB activities were suppressed in the more progressed cell lines 16RH and 18 v-fos but not in the less progressed 16RL or 18 cell lines. Overexpression of the same dominant negative c-jun did not inhibit p53 dependent reporter transactivation, indicating the specificity of inhibition of AP-1 and NF-κB transactivation in the HPV-immortalized cells. Stable transfectants of this mutant c-jun in the two more progressed cell lines 16RH and 18 v-fos showed reduced AP-1 and NF-κB activation and reduced anchorage-independent growth. Together, these results indicate that activation of AP-1, NF-κB or both may contribute to neoplastic progression in HPV immortalized human keratinocytes and that specific targeting of the elevated levels seen in benign or malignant tumors might be effective for prevention or treatment of human cancer.
Comparison of the bioavailability and tolerability of fixed-dose combination glimepiride/metformin 2/500-mg tablets versus separate tablets: A single-dose, randomized-sequence, open-label, two-period crossover study in healthy Korean volunteers
Objective: This study compared the bioavailability and tolerability of a fixed-dose combination (FDC) tablet of glimepiride/metformin 2/500 mg and glimepiride 2-mg + metformin 500-mg tablets administered separately in healthy Korean subjects. Methods: In this single-dose, open-label, 2-period crossover study, healthy Korean volunteers were randomly assigned to receive, in 1 of 2 randomized sequences, an FDC tablet of glimepiride/metformin 2/500 mg (test) and glimepiride 2-mg + metformin 500-mg tablets administered separately (reference), with a 1-week washout period between treatments. Plasma concentrations of glimepiride and metformin were measured using LC/MS-MS. Pharmacokinetic parameters were analyzed using noncompartmental methods. Bioequivalence was concluded if the 90% CIs of the geometric mean test/reference ratios (GMRs) of the logarithm-transformed C max, AUC from 0 to 30 hours (AUC 0–30), and AUC 0−∞ values were within the predetermined regulatory range of 80% to 125%. Tolerability was assessed using physical examination and laboratory analysis. Results: A total of 32 subjects were enrolled (16 men [mean (SD) age, 21.8 (2.7) years (range, 18–26 years); weight, 68.9 (8.3) kg (range, 55.5–85.0 kg)]; 16 women [age, 23.5 (4.5) years (range, 20–38 years); weight, 51.7 (3.5) kg (range, 46.8–58.0 kg)]). The GMRs (90% CI) of glimepiride C max, AUC 0–30, and AUC 0−∞ were 1.01 (0.91–1.11), 0.98 (0.92–1.03), and 0.97 (0.93–1.04), respectively. For metformin, these values were 0.96 (0.87–1.06), 0.96 (0.90–1.03), and 0.96 (0.90–1.03). A total of 49 adverse events (AEs) were reported in 10 subjects (31.3%) with the FDC and in 13 subjects (40.6%) with the separate tablets. The most commonly reported AEs with the test and reference treatments were dizziness (6 [19%] and 7 [22%]) and sweating (4 [13%] and 7 [22%]), respectively. The severity of all of the AEs was considered to be mild, and there were no significant differences in the prevalences of AEs between the 2 formulations. Conclusions: In this study in healthy Korean subjects, the requirements for bioequivalence of the glimepiride/metformin 2/500-mg FDC and coadministration of separate tablets of each drug were met. Both formulations were generally well tolerated.
Somatic Mutations of Fas (Apo-1/CD95) Gene in Cutaneous Squamous Cell Carcinoma Arising from a Burn Scar
Fas (Apo-1/CD95) is a cell-surface receptor involved in cell death signaling, and recent reports have suggested that defects within the Fas receptor pathway such as Fas mutation play an important part in the development and progression of human tumors. Burn scar-related squamous cell carcinoma of skin is a unique subtype of cutaneous squamous cell carcinoma, and tends to be more aggressive in nature than conventional squamous cell carcinoma. The molecular mechanisms underlying the development and progression of burn scar-related squamous cell carcinoma, however, are not clear. In this study, we analyzed the entire coding region and all splice sites of the Fas gene for the detection of the somatic mutations in a series of 50 conventional squamous cell carcinomas and 21 burn scar-related squamous cell carcinomas by polymerase chain reaction, single strand conformation polymorphism, and DNA sequencing. We detected mis-sense mutations in three of 21 burn scar-related squamous cell carcinomas (14.3%), whereas no mutation was detected in 50 conventional squamous cell carcinomas. Of the three Fas mutations detected in the burn scar-related squamous cell carcinomas, one was found in Fas ligand-binding domain, another one was identified in the death domain known to be involved in the transduction of an apoptotic signal, and the other one was found in the transmembrane domain. Our data show that some burn scar-related squamous cell carcinomas have Fas gene mutations in important regions for the apoptosis function and suggest that these mutations might be involved in the pathogenesis of burn scar-related squamous cell carcinomas. In addition, our results provide an important clue to understanding the difference between burn scar-related squamous cell carcinoma and conventional squamous cell carcinoma at the molecular level.