Alumina nanofibers were prepared by a technique that combined the sol–gel and electrospinning methods. The solution to be electrospun was prepared by mixing aluminum isopropoxide (AIP) in ethanol, which was then refluxed in the presence of an acid catalyst and polyvinylpyrolidone (PVP) in ethanol. The characterization results showed that alumina nanofibers with diameters in the range of 102 to 378 nm were successfully prepared. On the basis of the results of the XRD and FT-IR, the alumina nanofibers calcined at 1,100°C were identified as comprising the α-alumina phase, and a series of phase transitions such as boehmite → γ-alumina → α-alumina were observed from 500°C to 1,200°C. The pore size of the obtained γ-alumina nanofibers is approximately 8 nm, and it means that they are mesoporous materials. The kinetic study demonstrated that MO adsorption on alumina nanofibers can be seen that the pseudo-second-order kinetic model fits better than the pseudo-first-order kinetic model.
Alumina nanofibers; Electrospinning; Adsorption; Pseudo-second-order kinetic
Myeloid sarcoma is a solid, extramedullary tumor composed of leukemic myeloblasts or immature myeloid cells. Intraparenchymal myeloid sarcoma without the involvement of the skull or meninges is extremely rare. Here, we present the case of a 49-year-old man who developed intraparenchymal myeloid sarcoma on the left cerebellum after allogeneic bone marrow transplantation (BMT). He received radiotherapy after complete removal of intraparenchymal myeloid sarcoma, but he was diagnosed spinal myeloid sarcoma three month later. Nine months after the operation, new intracranial and spinal myeloid sarcoma were diagnosed and the patient's condition had been worsened rapidly. Although the spinal myeloid sarcoma was not histologically diagnosed, this report provides valuable insights into the clinical course of progression of intraparenchymal myeloid sarcoma.
Myeloid sarcoma; Acute myeloid leukemia; Bone marrow transplantation
The authors report a case of 42-year-old woman with an intraventricular tumor in the trigone of the left lateral ventricle. The first operation achieved a microscopically complete resection. The tumor was histologically atypical meningioma. After 26 months, there were recurrences of intraventricular meningioma. Complete resection of the tumor and adjuvant radiation therapy were performed, and the histological diagnosis was malignant meningioma. Sixteen months after the second operation, spinal metastasis in cervicolumbar lesion was diagnosed and a subtotal removal of cervical intradural extramedullary mass was performed. We describe an unusual case of intraventricular malignant meningioma with cerebrospinal fluid-disseminated spinal metastases with review of the clinical courses of previous reports.
Malignant meningioma; Intraventricular neoplasms; Spinal metastases
The authors present a case of 68-year-old woman who underwent resection of a metastatic adenocarcinoma in the left parietooccipital area. The intraoperative course was uneventful; however, after closure of the scalp incision, increased bleeding from the suture line was noted. A computerized tomography scan that was performed immediately after operation revealed acute epidural hemorrhage with mass effect under the bone flap. The patient developed disseminated intravascular coagulation and immediate re-exploration was performed. This patient was successfully treated owing to early recognition of the condition and immediate treatment with transfusion. Neurosurgeons should be alert that hypercoagulabe state is common in cancer patients and consumptive coagulopathy can occur after resection of metastatic brain tumor.
Disseminated intravascular coagulation; Brain tumor; Blood transfusion; Hemostasis
Photo-responsive bioconjugation empowers the development of novel methods for drug discovery, disease diagnosis, and high-throughput screening, among the others. In this paper, we report on the characteristics of a traceless photo-cleavable cross-linker, di 6-(3-succinimidyl carbonyloxymethyl-4-nitro-phenoxy)-hexanoic acid disulfide diethanol ester (SCNE). The traceless feature and the biocompatibility of this photo-cleavable cross-linking reagent were corroborated. Consequently, we demonstrated its application in reversible phage particle immobilization that could provide a platform for direct single phage screening. We also applied it in protein-photoprinting, where SCNE acts as a “photo-eraser” to remove the cross-linked protein molecules at a desired region in a simple, clean and light-controllable fashion. We further demonstrated the two-tier atomic force microscopic (AFM) method that uses SCNE to carry out two subsequent AFM tasks in situ. The approach allows guided protein delivery and subsequent high-resolution imaging at the same local area, thus opens up the possibility of monitoring protein functions in live cells. The results imply that SCNE is a versatile cross-linker that can be used for a wide range of applications where photo-cleavage ensures clean and remote-controllable release of biological molecules from a substrate.
Astroblastoma is a rarely diagnosed primary brain neoplasm whose histogenesis has been clarified recently. It occurs in children and young adults and presents as a well circumscribed, contrast-enhancing lesion in the cerebral hemisphere. We present a case of 20-year-old woman with an astroblastoma in the left temporal convexity that was treated with total tumor resection alone. We thought the mass was extra-axial neoplasm based on radiological findings of computed tomography and magnetic resonance imaging initially, but later, we obtained angiographic findings suggesting an intra-axial neoplasm. The patient is doing well even two years after surgery. The characteristic radiological and histopathological features of this case are described with a literature review. An astroblastoma should be included in the differential diagnosis of a superficially located tumor presenting with the findings of an extra-axial mass, especially in a young patient.
Astroblastoma; Intra-axial neoplasm
Arsenic trioxide (As2O3) has been used as an anticancer agent in traditional Chinese medicine for thousand years and berberine is an isoquinoline alkaloid present that has indicated significant antimicrobial activity. We have examined the combined anticancer effects of As2O3 and berberine against the human neuroblastoma (HNB) SH-SY5Y cells in vitro, and to elucidate underlying molecular mechanism.
HNB SH-SY5Y cells were treated with 2 µM As2O3 and 75 µg/ml berberine, and their survival, cell death mechanism as well as synergistic cytotoxic effects were estimated by using MTT assay, DAPI staining, agarose gel electrophoresis, flow cytometric analysis, and western blot analysis.
The combined treatment of two drugs also markedly decreased cell viability. The cytotoxic effects of two drugs were revealed as apoptosis characterized by chromatin condensation, DNA fragmentation, and the loss of mitochondrial membrane potential. The apoptotic cytotoxicity was accompanied by activation of caspase-3 protease as well as decreased the expression of Bcl-2, Bid, and Bcl-x/L. In addition, the cells treated with combination of two drugs also showed significantly increased intracellular reactive oxygen species levels and lipid peroxidation compared to cells As2O3 or berberine only.
Combined treatment of As2O3 with berberine induced activation of apoptotic signaling pathways in HNB SH-SY5Y cells. These results suggest that the possibility of the combined treatment of two chemotherapeutic agents with low concentration improving cytotoxic effect for cancer cells with minimal side effects.
Human neuroblastoma SH-SY5Y cells; Arsenic trioxide; Berberine; Apoptosis
[Purpose] This study investigated the effect of different gait speeds on the muscle
activities of the latissimus dorsi and gluteus maximus muscles in relation to the
posterior oblique sling system. [Subjects] We recruited 14 young adult males. [Methods] We
measured the left latissimus dorsi muscle activity and right gluteus maximus muscle
activity of all subjects while they walked on a treadmill at speeds of 1.5 km/h, 3.5 km/h
and 5.5 km/h. [Results] There was a significant increase in latissimus dorsi muscle
activity with a treadmill speed of 5.5 km/h compared with 1.5 km/h and 3.5 km/h. The
gluteus maximus muscle activity significantly increased in the order of 1.5 km/h <
3.5 km/h < 5.5 km/h. [Conclusion] The present results indicate that arm swing connected
to increasing gait speed influences the muscle activity of the lower limbs through the
posterior oblique sling system.
Electromyography; Gait speed; Posterior oblique sling system
[Purpose] This study researched the effects of different gait speeds and lower arm
weight on the activities of the latissimus dorsi, gluteus medius, and gluteus maximus
muscles. [Subjects] Fourteen healthy adult men participated in this study. [Methods] All
the participants carried out walking on a treadmill at speeds of 3.5 km/h and 5.5 km/h for
half a minute. During treadmill gait, electromyographic activity muscle was measured of
the latissimus dorsi, gluteus medius and gluteus maximus. [Result] There were significant
differences in the muscle activities due to changes in gait speed and lower arm load in
the latissimus dorsi and gluteus maximus, but there were no significant differences in the
muscle activities of the gluteus medius. [Conclusion] According to our results, arm swing
is related to increasing gait speed, and lower arm load is influences the muscle activity
of the lower extremities through the posterior oblique sling system.
Posterior oblique sling system; Arm weight; Arm swing
The regulation of mitochondrial function is essential for cardiomyocyte adaptation to cellular stress. While it has long been understood that phosphorylation regulates flux through metabolic pathways, novel phosphorylation sites are continually being discovered in all functionally distinct areas of the mitochondrial proteome. Extracting biologically meaningful information from these phosphorylation sites requires an adaptable, sensitive, specific and robust method for their quantification. Here we report a multiple reaction monitoring-based mass spectrometric workflow for quantifying site-specific phosphorylation of mitochondrial proteins. Specifically, chromatographic and mass spectrometric conditions for 68 transitions derived from 23 murine and human phosphopeptides, and their corresponding unmodified peptides, were optimized. These methods enabled the quantification of endogenous phosphopeptides from the outer mitochondrial membrane protein VDAC, and the inner membrane proteins ANT and ETC complexes I, III and V. The development of this quantitative workflow is a pivotal step for advancing our knowledge and understanding of the regulatory effects of mitochondrial protein phosphorylation in cardiac physiology and pathophysiology.
Phosphorylation; Mitochondria; Cardiovascular Disease; Protein Quantitation; MRM
Mitochondrial protein homeostasis is an essential component of the functions and oxidative stress responses of the heart.
To determine the specificity and efficiency of proteome turnover of the cardiac mitochondria by endogenous and exogenous proteolytic mechanisms.
Methods and Results
Proteolytic degradation of the murine cardiac mitochondria was assessed using two-dimensional differential gel electrophoresis (2D-DIGE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Mitochondrial proteases demonstrated a substrate preference for basic protein variants, indicating a possible recognition mechanism based on protein modifications. Endogenous mitochondrial proteases and the cytosolic 20S proteasome exhibited different substrate specificities.
The cardiac mitochondrial proteome contains low amounts of proteases and is remarkably stable in isolation. Oxidative damage lowers the proteolytic capacity of cardiac mitochondria and reduces substrate availability for mitochondrial proteases. The 20S proteasome preferentially degrades specific substrates in the mitochondria and may contribute to cardiac mitochondrial proteostasis.
Protein degradation; mitochondrial proteome; protein turnover; cardiac homeostasis
Factors such as lipids or cholesterol crystals in body fluids can cause a spurious elevation of leukocytes (WBC) in an automated cell count. This artifact can occur in automated WBC counts of hip fluid from femoral head osteonecrosis (ON), and an erroneous diagnosis of septic arthritis can be made.
We describe the frequency of this artifactual leukocytosis in femoral head ON and how to differentiate it from septic arthritis.
From September 1997 to June 2004, 414 patients (486 hips) with femoral head ON were scheduled to undergo THAs. Although we had no preoperative suspicion of infection, we intraoperatively suspected concomitant pyogenic arthritis in eight patients (eight hips) because pus-like fluid gushed from the joint during the operation. To confirm the presence or absence of infection we intraoperatively evaluated the joint fluid with automated blood cell count and microscopy. The automated WBC count was elevated in all eight patients. In seven of the eight patients, WBCs were not identified under microscopic observation and the leukocytosis of automated cell counting was considered to be erroneous. These seven patients underwent THAs. The minimum followup was 3 years (average, 45 months; range, 36–60 months).
These seven patients were considered to have a spurious elevation of WBC (range, 4500–18,400/mm3; mean, 8970/mm3) in an automated cell count. The prevalence of the spurious leukocytosis was 1.4% (7/414) in osteonecrotic hips. In all seven patients, we observed numerous fat cells and globules instead of WBCs under microscopic observation. No bacteria were seen in the smear and culture of the joint fluid. The seven patients underwent THAs, and no patient had a subsequent deep wound infection as of the last followup.
Fatty joint effusion in an osteonecrotic hip may appear like pus and erroneously can be interpreted as leukocytes in an automated cell count. In this situation, a microscopic evaluation of joint fluid smear should be performed to determine the presence of infection and the treatment method.
Level of Evidence
Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.
Granulocyte-colony stimulating factor (G-CSF) is extensively used to improve neutrophil count during anti-cancer chemotherapy. We investigated the effects of G-CSF on several leukemic cell lines and screened for the expression of the G-CSF receptor (G-CSFR) in various malignant cells.
We examined the effects of the most commonly used commercial forms of G-CSF (glycosylated lenograstim and nonglycosylated filgrastim) on various leukemic cell lines by flow cytometry. Moreover, we screened for the expression of G-CSFR mRNA in 38 solid tumor cell lines by using real-time PCR.
G-CSF stimulated proliferation (40-80% increase in proliferation in treated cells as compared to that in control cells) in 3 leukemic cell lines and induced differentiation of AML1/ETO+ leukemic cells. Among the 38 solid tumor cell lines, 5 cell lines (hepatoblastoma, 2 breast carcinoma, squamous cell carcinoma of the larynx, and melanoma cell lines) showed G-CSFR mRNA expression.
The results of the present study show that therapeutic G-CSF might stimulate the proliferation and differentiation of malignant cells with G-CSFR expression, suggesting that prescreening for G-CSFR expression in primary tumor cells may be necessary before using G-CSF for treatment.
G-CSF; Differentiation; Proliferation; Solid tumor; AML
Mucosa-associated lymphoid tissue (MALT) lymphoma is one of the most common lymphomas and accounts for about 7% of all newly diagnosed non-Hodgkin's lymphoma (NHL). The clinical course of MALT lymphoma is relatively indolent and, in the majority of cases (50%), the lymphoma arises within the stomach. Primary central nervous system lymphoma (PCNSL), an uncommon variant of extranodal NHL, can affect any part of the neuraxis, including the eyes, brain, leptomeninges, or spinal cord. Herein, we present a rare case of PCNSL, which occurred one year after radiochemotherapy of gastric MALT lymphoma. A 62-year-old man presented with a 3-day history of left facial palsy. One year ago, he underwent antibiotic eradication therapy of Helicobacter pylori, local stomach fractional radiotherapy, and chemotherapy for gastric MALT lymphoma. Magnetic resonance imaging revealed a strong enhancing solid mass in the right frontal lobe. The tumor was completely removed, and the histological diagnosis of PCNSL developing from diffuse large B-cell lymphoma was made. Although elucidating the correlation between the first gastric MALT lymphoma and the second PCNSL seemed difficult, we have postulated and discussed some possible pathogeneses, together with a review of literature.
MALT Lymphoma; Diffuse large B-Cell lymphoma
The present study identified a novel salinomycin (Sal) sensitization mechanism in cancer. We tested whether Sal reduced proliferation in a high-density population by counting attached cell numbers after Sal treatment. Sal reduced proliferation in high-density cell populations. Longer exposure to Sal further reduced proliferation. Sal concentrations of 0.1 and 5 μM had similar sensitization effects, suggesting that Sal toxicity was minimal with longer exposure to a high-density cell population. The results suggest that Sal can be applied at a relatively low concentration for a longer time to overcome drug-resistant solid tumors. The 0.5 μM Sal treatment resulted in fewer attached cells than that of the 5 μM Sal treatment with a longer exposure. The lower Sal concentration mainly increased the number of easily detachable cells on the surface. In particular, 0.5 μM Sal increased cellular detachment of newly produced daughter cells. The easily-detachable cells were undergoing apoptosis. It seems that the 0.5 μM Sal treatment also increased cellular toxicity. These novel findings may contribute to the development of Sal-based therapy for patients with drug-resistant cancer or a high-density solid tumor.
salinomycin; apoptosis; high cell density; spaces among cells; cellular detachment; lower concentration
The aim of the present study was to investigate the disagreement of cephalometric analysis depending on the reference determination of midsagittal plane on three-dimensional computed tomography.
Materials and Methods
A total of 102 young women with class III dentofacial deformity were evaluated using three-dimensional computed tomography. The cranial and facial midsagittal planes were defined and the amounts of jaw deviation were calculated. The amounts of jaw deviation were compared with paired t-test (2-tailed) and Bland-Altman plot was drawn.
The landmark tracing were reproducible (r≥.978). The jaws relative to the cranial midsagittal plane were 10-17 times more significantly deviated than to the facial midsagittal plane (P<.001). Bland-Altman plot demonstrated that the differences between the amounts of jaw deviation from two midsagittal planes were not normally distributed versus the average of the amounts of jaw deviation from two midsagittal planes.
The cephalometric analyses of facial asymmetry were significantly inconsistent depending on the reference determination of midsagittal plane. The reference for midsagittal plane should be carefully determined in three-dimensional cephalometric analysis of facial asymmetry of patients with class III dentofacial deformity.
Cephalometry; Facial Asymmetry; Tomography, X-Ray Computed; Imaging Three-Dimensional
Occipital neuralgia is usually defined as paroxysmal stabbing pain in the greater or lesser occipital nerve (GON or LON) distribution. In occipital neuralgia patients, surgical considerations are carefully taken into account if medical management is ineffective. However, identification of the occipital artery by palpation in patients with thick necks or small occipital arteries can be technically difficult. Therefore, we established a new technique using transcranial Doppler (TCD) sonography for more accurate and rapid identification. The patient was a 64-year-old man who had undergone C1-C3 screw fixation and presented with intractable stabbing pain in the bilateral GON and LON distributions. In cases in which pain management was performed using medication, physical therapy, nerve block, or radiofrequency thermocoagulation, substantial pain relief was not consistently achieved, and recurrence of pain was reported. Therefore, we performed occipital neurectomy of the bilateral GON and LON by using TCD sonography, which helped detect the greater occipital artery easily. After the operation, the patient's headache disappeared gradually, although he had discontinued all medication except antidepressants. We believe that this new technique of occipital neurectomy via a small skin incision performed using TCD sonography is easy and reliable, has a short operative time, and provides rapid pain relief.
neurectomy; occipital neuralgia; transcranial Doppler sonography
The aim of this study was to evaluate the effect of liquid crystal display (LCD) monitor type and observer experience on the diagnostic performance in soft-copy interpretations of maxillary sinus inflammatory lesions on panoramic radiographs.
Materials and Methods
Ninety maxillary sinuses on panoramic images were grouped into negative and positive groups according to the presence of inflammatory lesions, using CT for confirmation. Monochrome and color LCDs were used. Six observers participated and ROC analysis was performed to evaluate the diagnostic performance. The reading time, fatigue score, and inter-/intra-observer agreements were assessed.
The interpretation of maxillary sinus inflammatory lesions was affected by the LCD monitor type used and by the experience of the observer. The reading time was not significantly different, however the fatigue score was significantly different between two LCD monitors. Inter-observer agreement was relatively good in experienced observers, while the intra-observer agreement for all observers was good with monochrome LCD but not with color LCD.
The less experienced observers showed lowered diagnostic ability with a general color LCD.
Maxillary Sinus; Task Performance; ROC curve
This study aimed to examine the effectiveness of quetiapine and the effects of dosage relates to its effectiveness on schizophrenia and schizoaffective disorder in a naturalistic setting in Korean people.
This study was a 24-week, open-label, non-comparative, naturalistic study of quetiapine in patients diagnosed with schizophrenia and schizoaffective disorder according to DSM-IV. We stratified the patients into mild [(clinical global impression severity (CGI-S) <4 at baseline)] and severe groups (CGI-S ≥4 at baseline). We investigated the response rate, defined as clinical global impression improvement (CGI-I) ≤2, in the severe group and the aggravation rate in the mild group using the last-observation-carried-forward (LOCF) and the Kaplan-Meier method (K-M).
During the 24 weeks, 151 (18.4%) of the participants dropped out of the study. There was a significant decrease in the mean CGI-S score, from 4.5±1.1 at baseline to 2.8±1.1 at 24 weeks. The response rate of severe group was 54.5% (estimated by LOCF) and 73.3% (K-M estimated) at 24 weeks. All patients who completed the study had taken a mean quetiapine dosage of 507.9±245.9 mg daily. The decrease of CGI-S score in high-dose group (the maximum dose was 750 mg/d or above) was statistically significant than that in recommended-dose group (the maximum dose was less than 750 mg/d).
This study demonstrated the long-term effectiveness of quetiapine in the treatment of schizophrenia and schizoaffective disorder in a naturalistic setting in Korean people. This study suggests that higher than recommended quetiapine dosages could be more effective in some patients.
Schizophrenia; Quetiapine; Naturalistic study; High-dose
Treating young patients with femoral head osteonecrosis (ON) remains challenging. Anatomic stems were introduced in the 1980s and 1990s to improve the proximal canal fit in an attempt to enhance long-term implant survival, an important aspect of treating young patients. We began using one design in 1993 and asked three questions to confirm whether the design criteria improved outcomes in patients with ON: (1) What is the long term survivorship of these implants?; (2) What is the amount and rate of wear?; and (3) What is the incidence of osteolysis? We retrospectively reviewed 56 patients (69 hips) who underwent THA for femoral head ON with a cementless anatomic stem proximally coated with hydroxyapatite. Four patients (four hips) were lost to followup and 16 patients (19 hips) died. In the remaining 36 patients (46 hips) the minimum followup was 10 years (mean, 11.2 years; range, 10–13 years). The mean age at operation was 48.6 years. The average Harris hip score at last followup was 87 points. Worst-case survivorship was 58.1% at 13 years and best-case was 93.3%. The average linear wear of the polyethylene liner was 2.02 mm and the average annual wear was 0.18 mm per year. Thirty-seven hips (80%) had femoral osteolysis and 14 (30%) had acetabular osteolysis. One patient who had extensive femoral osteolysis and stem loosening was revised at 11.2 years postoperatively. The high rates of polyethylene wear and osteolysis are of concern.
Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
Acute epidural hematoma (AEDH) occurring as a result of traumatic head injury constitutes one of the most critical emergencies in neurosurgery. However, there are only several reports that show the rapid disappearance of AEDH without surgical intervention. We suggest redistribution of hematoma through the overlying skull fractures as the mechanism of rapid disappearance of AEDH. A 13-year-old female fell from a height of about 2 m and presented with mild headache. A computed tomography (CT) scan performed 4 hours after the injury revealed an AEDH with an overlying fracture in the right temporal region and acute small hemorrhagic contusion in the left frontal region. A repeat CT scan 16 hours after injury revealed that the AEDH had almost completely disappeared and showed an increase in the epicranial hematoma. The patient was discharged 10 days after injury with no neurological deficits. This case is characterized by the rapid disappearance of an AEDH associated with an overlying skull fracture. We believe that the rapid disappearance of the AEDH is due to the redistribution of the hematoma, rather than its resolution or absorption, and fracture plays a key role in this process.
Acute epidural hematoma; Rapid disappearance; Redistribution
We investigated whether the presence of diabetes mellitus (DM) was related to the degree of the anemia in predialytic patients with renal failure and what was the most relevant factor for anemia in patients with chronic kidney disease (CKD) from DM (DM-CKD).
Seventy seven patients (47 predialytic patients with long-term type 2 DM (DM-CKD) and 30 predialytic patients whose disease was due to other causes (non DM-CKD)) were enrolled in this study. The blood hemoglobin (Hb) and hematocrit, and the creatinine, ferritin, vitamin B12, folate, iron, LDH, albumin, hs-CRP, intact-PTH, erythropoietin, leptin and Insulin-like growth factor I (IGF-1) levels were measured using standard methods. The estimated GFR was calculated using the abbreviated MDRD equation.
The two groups did not significantly differ as to age, gender, the serum creatinine level and the inflammatory status. The Hb level was significantly lower in the DM-CKD patients than that in the non DM-CKD patients (8.5±1.7 g/dL vs 9.6±1.6 g/dL, respectively, p=0.01). The Hb level was significantly lower in the DM-CKD patients who were being treated with ACE inhibitors (the DM-ACE patients) than that in the non DM-CKD patients who were being treated with ACE inhibitors (the non DM-ACE patients) (8.5±1.5 g/dL vs 10.8±1.6 g/dL, respectively, p=0.001). Multiple regression analysis indicated that serum IGF-1 concentration was independently associated with the Hb level (β=0.425, p=0.02) in the DM-CKD patients.
The Hb concentration was significantly lower in the DM-CKD patients than that in the non DM-CKD patients. It was independently associated with the serum IGF-1 concentration in the DM-CKD patients.
Diabetes mellitus; Kidney failure; Anemia; Insulin-like growth factor I; ACE inhibitor
We wanted to demonstrate the anti-cancer effect and interaction between belotecan and cisplatin on gastric cancer cell line and we evaluated the mechanisms of this synergistic effect in vitro.
Materials and Methods
The growth inhibitory effect of belotocan and cisplatin against several gastric cancer cell lines (SNU-5, SNU-16 and SNU-601) was estimated by tetrazolium dye assay. The effect of a combination treatment was evaluated by the isobologram method. The biochemical mechanisms for the interaction between the drugs were analyzed by measuring the formation of DNA interstrand cross-links (ICLs) and DNA topo-I activity.
Belotecan showed synergism with cisplatin for growth inhibitory effect on the gastric cancer cell lines SNU-5, and SNU-16, but this was subadditive on the SNU-601 cell line. The formation of DNA ICLs in SNU-16 cells by cisplatin was increased by combination with belotecan, but this was not affected in SNU-601 cells. The topo-I inhibition by belotecan was enhanced at high concentrations of cisplatin in SNU-16, but not in SNU-601 cells.
Belotecan and cisplatin show various combination effect against gastric cancer cells. The synergism between cisplatin and belotecan could be the result of one of the following mechanisms: the modulating effect of belotecan on the repair of cisplatin-induced DNA adducts and the enhancing effect of cisplatin on the belotecan-induced topo-I inhibitory effect.
Belotecan; Cisplatin; Synergism; Stomach neoplasms
Integrin-mediated cell adhesion and spreading enables cells to respond to extracellular stimuli for cellular functions. Using a gastric carcinoma cell line that is usually round in adhesion, we explored the mechanisms underlying the cell spreading process, separate from adhesion, and the biological consequences of the process. The cells exhibited spreading behavior through the collaboration of integrin-extracellular matrix interaction with a Smad-mediated transforming growth factor β1 (TGFβ1) pathway that is mediated by protein kinase Cδ (PKCδ). TGFβ1 treatment of the cells replated on extracellular matrix caused the expression and phosphorylation of PKCδ, which is required for expression and activation of integrins. Increased expression of integrins α2 and α3 correlated with the spreading, functioning in activation of focal adhesion molecules. Smad3, but not Smad2, overexpression enhanced the TGFβ1 effects. Furthermore, TGFβ1 treatment and PKCδ activity were required for increased motility on fibronectin and invasion through matrigel, indicating their correlation with the spreading behavior. Altogether, this study clearly evidenced that the signaling network, involving the Smad-dependent TGFβ pathway, PKCδ expression and phosphorylation, and integrin expression and activation, regulates cell spreading, motility, and invasion of the SNU16mAd gastric carcinoma cell variant.