Identification of CD133-positive radioresistant cells in atypical teratoid/rhabdoid tumor

Atypical teratoid/rhabdoid tumor (AT/RT) is an extremely malignant neoplasm in the central nervous system (CNS) which occurs in infancy and childhood. Recent studies suggested that CD133 could be considered a marker for brain cancer stem-like cells (CSCs). However, the role of CD133 in AT/RT has never been investigated. Herein we report the isolation of CD133-positive cells (CD133⁺), found to have the potential to differentiate into three germ layer tissues, from tissues of nine AT/RT patients. The migration/invasion/malignancy and radioresistant capabilities of CD133⁺ were significantly augmented when compared to CD133⁻. The clinical data showed that the amount of CD133⁺ in AT/RTs correlated positively with the degree of resistance to radiation therapy. Using cDNA microarray analysis, the genotoxic–response profiles of CD133⁺ and CD133⁻ irradiated with 10 Gy ionizing radiation (IR) were analyzed 0.5, 2, 6, 12 and 24 h post-IR. We then validated these microarray data and showed increased phosphorylation after IR of p-ATM, p-RAD17, and p-CHX2 as well as increased expression of BCL-2 protein in CD133⁺ compared to CD133⁻. Furthermore, we found that CD133⁺ can effectively resist IR with cisplatin- and/or TRAIL-induced apoptosis. Immunohistochemical analysis confirmed the up-regulated expression of p-ATM and BCL-2 proteins in IR-treated CD133⁺ xenotransgrafts in SCID mice but not in IR-treated CD133⁻. Importantly, the effect of IR in CD133⁺ transplanted mice can be significantly improved by a combination of BCL-2 siRNA with debromohymenialdisine, an inhibitor of checkpoint kinases. In sum, this is the first report indicating that CD133⁺ AT/RT cells demonstrate the characteristics of CSCs. The IR-resistant and anti-apoptotic properties in CD133⁺ may reflect the clinical refractory malignancy of AT/RTs and thus the activated p-ATM pathway and BCL-2 expression in CD133⁺ could be possible targets to improve future treatment of deadly diseases like AT/RT.

Tumour necrosis factor-alpha enhances bradykinin-induced signal transduction via activation of Ras/Raf/MEK/MAPK in canine tracheal smooth muscle cells

Inhalation of tumour necrosis factor-alpha (TNF-alpha) induced a bronchial hyperreactivity to contractile agonists. However, the mechanisms of TNF-alpha involved in the pathogenesis of bronchial hyperreactivity were not completely understood. Therefore, we investigated the effect of TNF-alpha on bradykinin (BK)-induced inositol phosphate (IP) accumulation and Ca(2+) mobilization, and up-regulation of BK receptor density in canine cultured tracheal smooth muscle cells (TSMCs). Pretreatment of TSMCs with TNF-alpha potentiated BK-induced IP accumulation and Ca(2+) mobilization. However, there was no effect on the IP response induced by endothelin-1 (ET-1), 5-hydroxytryptamine (5-HT), and carbachol. Pretreatment with PDGF B-chain homodimer (PDGF-BB) also enhanced BK-induced IP response. These enhancements induced by TNF-alpha and PDGF-BB might be due to an increase in BK B(2) receptor density (B(max)), since [3H]BK binding to TSMCs was inhibited by the B(2) selective agonist and antagonist, BK and Hoe 140, but not by the B(1) selective reagents. The enhancing effects of TNF-alpha and PDGF-BB were attenuated by PD98059 (an inhibitor of activation of MAPK kinase, MEK) and cycloheximide (an inhibitor of protein synthesis), suggesting that TNF-alpha may share a common signalling pathway with PDGF-BB via protein(s) synthesis in TSMCs. Furthermore, overexpression of dominant negative mutants, H-Ras-15A and Raf-N4, significantly suppressed p42/p44 mitogen-activated protein kinase (MAPK) activation induced by TNF-alpha and PDGF-BB and attenuated the effect of TNF-alpha on BK-induced IP response, indicating that Ras and Raf may be required for activation of these kinases. These results suggest that the augmentation of BK-induced responses produced by TNF-alpha might be, at least in part, mediated through activation of Ras/Raf/MEK/MAPK pathway in TSMCs.

Mechanisms of thrombin-induced MAPK activation associated with cell proliferation in human cultured tracheal smooth muscle cells

The elevated level of thrombin has been detected in the airway fluids of asthmatic patients. However, the implication of thrombin in the pathogenesis of bronchial hyperreactivity was not completely understood. Therefore, in this study we investigated the effect of thrombin on cell proliferation and p42/p44 mitogen-activated protein kinase (MAPK) activation in human tracheal smooth muscle cells (TSMCs). Thrombin stimulated [3H]thymidine incorporation and p42/p44 MAPK phosphorylation in a time- and concentration-dependent manner in TSMCs. Pretreatment of TSMCs with pertussis toxin (PTX) significantly inhibited [3H]thymidine incorporation and phosphorylation of MAPK induced by thrombin. These responses were attenuated by tyrosine kinase inhibitors genistein and herbimycin A, phosphatidyl inositide (PI)-phospholipase C (PLC) inhibitor U73122, protein kinase C (PKC) inhibitor GF109203X, removal of Ca(2+) by addition of BAPTA/AM plus EGTA, and PI 3-kinase inhibitors wortmannin and LY294002. In addition, thrombin-induced [3H]-thymidine incorporation and p42/p44 MAPK phosphorylation was completely inhibited by PD98059 (an inhibitor of MEK1/2), indicating that activation of MEK1/2 was required for these responses. Furthermore, overexpression of dominant negative mutants, RasN17 and Raf-301, significantly suppressed p42/p44 MAPK activation induced by thrombin and PDGF-BB, indicating that Ras and Raf may be required for activation of these kinases. These results conclude that the mitogenic effect of thrombin was mediated through the activation of Ras/Raf/MEK/MAPK pathway. Thrombin-mediated MAPK activation was modulated by PI-PLC, Ca(2+), PKC, tyrosine kinase, and PI 3-kinase associated with cell proliferation in cultured human TSMCs.

Mitogenic effect of oxidized low-density lipoprotein on vascular smooth muscle cells mediated by activation of Ras/Raf/MEK/MAPK pathway

1. It has been demonstrated that oxidized low-density lipoprotein (OX-LDL) is a risk factor in atherosclerosis by stimulating vascular smooth muscle cell (VSMC) proliferation. However, the mechanisms of OX-LDL-induced cell proliferation are not completely understood. Therefore, we investigated the effect of OX-LDL on cell proliferation associated with mitogen-activated protein kinase (MAPK) activation in rat cultured VSMCs. 2. Both native-LDL (N-LDL) and OX-LDL induced a time- and concentration-dependent incorporation of [(3)H]-thymidine in VSMCs. 3. OX-LDL induced time- and concentration-dependent phosphorylation of p42/p44 MAPK. Pretreatment of these cells with pertussis toxin or U73122 attenuated the OX-LDL-induced responses. 4. Pretreatment with PMA for 24 h, preincubation with a PKC inhibitor staurosporine or the tyrosine kinase inhibitors, genistein and herbimycin A for 1 h, substantially reduced [(3)H]-thymidine incorporation and p42/p44 MAPK phosphorylation induced by OX-LDL. 5. Removal of Ca(2+) by BAPTA/AM or depletion of the internal Ca(2+) pool by thapsigargin significantly inhibited OX-LDL-induced [(3)H]-thymidine incorporation and p42/p44 MAPK phosphorylation. 6. OX-LDL-induced [(3)H]-thymidine incorporation and p42/p44 MAPK phosphorylation was inhibited by PD98059 (an inhibitor of MEK1/2) and SB203580 (an inhibitor of p38 MAPK) in a concentration-dependent manner. 7. Overexpression of dominant negative mutants of Ras (H-Ras-15A) and Raf (Raf-N4) significantly suppressed MEK1/2 and p42/p44 MAPK activation induced by OX-LDL and PDGF-BB, indicating that Ras and Raf may be required for activation of these kinases. 8. These results suggest that the mitogenic effect of OX-LDL is mediated through a PTX-sensitive G protein-coupled receptor that involves the activation of the Ras/Raf/MEK/MAPK pathway similar to that of PDGF-BB in rat cultured VSMCs.

Interleukin-1beta enhances bradykinin-induced phosphoinositide hydrolysis and Ca2+ mobilization in canine tracheal smooth-muscle cells: involvement of the Ras/Raf/mitogen-activated protein kinase (MAPK) kinase (MEK)/MAPK pathway

Elevated levels of several cytokines including interleukin-1beta (IL-1beta) have been detected in airway fluid of asthmatic patients. Inhalation of IL-1beta induced a bronchial hyper-reactivity to contractile agonists. However, the implication of IL-1beta in the pathogenesis of bronchial hyper-reactivity is not completely understood. Therefore, we investigated the effect of IL-1beta on bradykinin (BK)-induced inositol phosphate [Ins(X)P] accumulation and Ca2+ mobilization, and up-regulation of BK receptor density in canine cultured tracheal smooth-muscle cells (TSMCs). Treatment of TSMCs with IL-1beta potentiated BK-induced Ins(X)P accumulation and Ca2+ mobilization. However, there was no effect on the Ins(X)P response induced by endothelin-1, 5-hydroxytryptamine or carbachol. Treatment with platelet-derived growth factor B-chain homodimer (PDGF-BB) also enhanced the BK-induced Ins(X)P response. These enhancements by IL-1beta and PDGF-BB might be due to an up-regulation of BK B(2) receptor density (B(max)), since [(3)H]BK binding to TSMCs was inhibited by the B(2)-selective agonist and antagonist, BK and Hoe 140, but not by B(1)-selective reagents. The enhancing effects of IL-1beta and PDGF-BB on Ins(X)P accumulation, Ca2+ mobilization and B(max) were attenuated by PD98059 [an inhibitor of activation of mitogen-activated protein kinase (MAPK) kinase, MEK] and cycloheximide (an inhibitor of protein synthesis), suggesting that IL-1beta may share a common signalling pathway with PDGF-BB via protein synthesis. Furthermore, overexpression of dominant negative mutants, H-Ras-15A and Raf-N4, significantly suppressed the up-regulation of BK receptors induced by IL-1beta, indicating that Ras and Raf may be required for activation of these kinases. These results suggest that the augmentation of BK-induced responses produced by IL-1beta might be, at least in part, mediated through activation of the Ras/Raf/MEK/MAPK pathway in TSMCs.

Tumour necrosis factor-alpha- and interleukin-1beta-stimulated cell proliferation through activation of mitogen-activated protein kinase in canine tracheal smooth muscle cells

The elevated levels of inflammatory cytokines such as tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) have been found in the fluid of airways in symptomatic asthmatics. These cytokines have been considered as mitogens to stimulate cell proliferation in tracheal smooth muscle cells (TSMCs). We therefore investigated the effects of TNF-alpha and IL-1beta on cell proliferation and activation of p42/p44 mitogen-activated protein kinase (MAPK) in these cells. TNF-alpha and IL-1beta induced [(3)H]-thymidine incorporation in a time- and concentration-dependent manner. The maximal stimulation of [(3)H]-thymidine incorporation induced by TNF-alpha and IL-1beta was seen 12 h after incubation with these cytokines. In response to TNF-alpha and IL-1beta, p42/p44 MAPK was activated with a concentration-dependent manner in TSMCs. Pretreatment of TSMCs with pertussis toxin did not change DNA synthesis and phosphorylation of MAPK induced by TNF-alpha and IL-1beta. These responses were attenuated by a tyrosine kinase inhibitor herbimycin, a phosphatidyl choline (PC)-phospholipase C (PLC) inhibitor D609, a phosphatidyl inositide (PI)-PLC inhibitor U73122, a protein kinase C inhibitor staurosporine, and removal of Ca(2+) by addition of BAPTA/AM plus EGTA. TNF-alpha- and IL-1beta-induced [(3)H]-thymidine incorporation and phosphorylation of p42/p44 MAPK was completely inhibited by PD98059 (an inhibitor of MEK1/2), indicating that activation of MEK1/2 was required for these responses. These results suggest that the mitogenic effects of TNF-alpha and IL-1beta were mediated through the activation of MEK1/2 and p42/p44 MAPK pathway. TNF-alpha- and IL-1beta-mediated responses were modulated by PLC, Ca(2+), PKC, and tyrosine kinase associated with cell proliferation in TSMCs.

Activation of mitogen-activated protein kinase by oxidized low-density lipoprotein in canine cultured vascular smooth muscle cells

Oxidized low-density lipoprotein (OX-LDL) contributes significantly to the development of atherosclerosis. However, the mechanisms of OX-LDL-induced vascular smooth muscle cell (VSMC) proliferation are not completely understood. Therefore, we investigated the effect of OX-LDL on cell proliferation associated with a specific pattern of mitogen-activated protein kinase (MAPK) by [3H]thymidine incorporation and p42/p44 MAPK phosphorylation in canine cultured VSMCs. OX-LDL-induced [3H]thymidine incorporation and p42/p44 MAPK phosphorylation in a time- and concentration-dependent manner in VSMCs. Pretreatment of these cells with pertussis toxin (PTX) for 24 hours attenuated the OX-LDL-induced [3H]thymidine incorporation and p42/p44 MAPK phosphorylation, indicating that these responses were mediated through a receptor coupled to a PTX-sensitive G protein. In cells pretreated with PMA for 24 h and with either the PKC inhibitor staurosporine or the tyrosine kinase inhibitor genistein for 1h, substantially reduced the [3H]thymidine incorporation and p42/p44 MAPK phosphorylation in response to OX-LDL. Removal of Ca(2+) by addition of BAPTA/AM plus EGTA significantly inhibited OX-LDL-induced [3H]thymidine incorporation and p42/p44 MAPK phosphorylation, indicating the requirement of Ca(2+) for these responses. OX-LDL-induced [3H]thymidine incorporation and p42/p44 MAPK phosphorylation was completely inhibited by PD98059 (an inhibitor of MEK1/2) and SB203580 (an inhibitor of p38 MAPK). Furthermore, we also showed that overexpression of dominant negative mutants of Ras (RasN17) and Raf (Raf-301) completely suppressed MEK1/2 and p42/p44 MAPK activation induced by OX-LDL and PDGF-BB, indicating that Ras and Raf may be required for activation of these kinases. Taken together, these results suggest that the mitogenic effect of OX-LDL is mediated through a PTX-sensitive G-protein-coupled receptor that involves the activation o Ras/Raf/MEK/MAPK pathway similar to those of PDGF-BB in canine cultured VSMCs.

Mechanisms underlying the inhibitory effect of propofol on the contraction of canine airway smooth muscle

BACKGROUND

Propofol has been shown to produce relaxation of preconstricted airway smooth muscle. Although the inhibition of calcium mobilization is supposed to be the major mechanism of action, the whole picture of the mechanisms is not completely clear.

METHODS

Contractile response was performed using canine tracheal rings. The effects of propofol on carbachol-induced mobilization of intracellular Ca2+ and phosphoinositide hydrolysis were measured using cultured canine tracheal smooth muscle cells by monitoring fura-2 signal and assessing the accumulation of [3H]-inositol phosphates. To detect the effect of propofol on muscarinic receptor density and affinity, [3H]N-methyl-scopolamine was used as a radioligand for receptor binding assay.

RESULTS

Pretreatment with propofol shifts the concentration-response curves of carbachol-induced smooth muscle contraction to the right in a concentration-dependent manner without changing the maximal response. Propofol not only decreased the release of Ca2+ from internal stores but also inhibited the calcium influx induced by carbachol. In addition, carbachol-induced inositol phosphate accumulation was attenuated by propofol; the inhibitory pattern was similar to the contractile response. Moreover, propofol did not alter the density of muscarinic receptors. The dissociation constant value was not altered by pretreatment with 100 microM propofol but was significantly increased by 300 microM (propofol, 952+/-229 pM; control, 588+/-98 pM; P<0.05).

CONCLUSIONS

Propofol attenuates the muscarinic receptor-mediated airway muscle contraction. The mechanism underlying these effects was attenuation of inositol phosphate generation and inhibition of Ca2+ mobilization through the inhibition of the receptor-coupled signal-transduction pathway.

5-Hydroxytryptamine-induced phosphoinositide hydrolysis and Ca2+ mobilisation in canine cultured aorta smooth muscle cells

The effect of 5-hydroxytryptamine (5-HT) on phospholipase C (PLC)-mediated phosphoinositide (PI) hydrolysis and intracellular Ca2+ ([Ca2+]i) changes was investigated in canine cultured aorta smooth muscle cells (ASMCs). 5-HT-stimulated inositol phosphate (IP) accumulation was time and concentration dependent with a half-maximal response (pEC50) and a maximal response at 6.4 and 10 microM, n = 6, respectively. Stimulation of ASMCs by 5-HT produced an initial transient peak followed by a sustained, concentration-dependent elevation in [Ca+]i. The half-maximal response (pEC50) values of 5-HT for the peak and sustained plateau were 7.1 and 6.9, respectively. Ketanserin and mianserin (1 and 3 nM), 5-HT2A antagonists, were equipotent and had high affinity in antagonising the 5-HT-induced IP accumulation and [Ca2+]i change with pK(B) values of 8.6-9.1 and 8.6-9.4, respectively. In contrast, the concentration-effect curves of 5-HT-induced IP and [Ca2+]i responses were not shifted until the concentrations of NAN-190 and metoctopramide (5-HT1A and 5-HT3 receptor antagonists, respectively) were increased to as high as 1 microM with pK(B) values of 5.7-6.3 and 6.1-6.6, respectively, indicating that the 5-HT receptor-mediated responses had low affinity for these antagonists. Pre-treatment of ASMCs with pertussis toxin (100 ng/mL, 24 h) caused a significant inhibition of 5-HT-induced IP accumulation and [Ca2+]i change in ASMCs. Depletion of external Ca2+ or removal of Ca2+ by addition of EGTA led to a significant attenuation of IP accumulation and [Ca2+]i change induced by 5-HT. Influx of external Ca2+ was required for the 5-HT-induced responses, because Ca2+-channel blockers--verapamil, nifedipine and Ni2+--partly inhibited the 5-HT-induced IP accumulation and Ca2+ mobilisation. The sustained elevation of [Ca2+]i response to 5-HT was dependent on the presence of external Ca2+. Removal of external Ca2+ by addition of 5 mM EGTA during the sustained phase caused a rapid decline in [Ca2+]i to lower than the resting level. The sustained elevation of [Ca2+]i could then be evoked by addition of 1.8 mM Ca2+ in the continued presence of 5-HT. These results demonstrate that 5-HT directly stimulates PLC-mediated PI hydrolysis and Ca2+ mobilisation, at least in part, through a pertussis toxin-sensitive G protein in canine ASMCs. 5-HT2A receptors may be predominantly mediating IP accumulation, and subsequently IP-induced Ca2+ mobilisation may function as the transducing mechanism for 5-HT-stimulated contraction of aorta smooth muscle.

[Small cell lung cancer with liver and bone metastasis associated with hypercalcemia and acute pancreatitis--a case report]

A 67-year-old man was hospitalized with the chief complaint of diffuse abdominal pain for 3 days. Hypercalcemia and acute pancreatitis was found by laboratory examination. Abdominal CT scans showed swelling of the pancreas, multiple liver tumors and osteolytic lesions of bone. Upper mediastinal lobulated mass was suspected from chest x-ray examination, then small cell lung cancer (SCLC) was proved by bronchoscopic and pathological examination. The final diagnosis is SCLC with liver and bone metastasis associated with hypercalcemia and acute pancreatitis. After pancreatitis subsided, the patient was put on chemotherapy. Unfortunately, due to immunocompromise, he died of pneumonia and sepsis. There was no reasonable explanation regarding to the cause of acute pancreatitis except hypercalcemia, which might be due to SCLC with bone metastasis. This is the first report of such a complication in a patient with SCLC.

Adipofascial turnover flap for facial contour deformity during parotidectomy

An adipofascial turnover flap is described. This vascularized flap is technically simple to perform and provides excellent cosmetic results for patients with a very large tumor undergoing superficial parotidectomy. The flap also acts as a barrier for regenerating nerves, preventing the development of gustatory sweating.

Carcinosarcoma of esophagus. Report of one case and review of the literature

Esophageal carcinosarcoma is a rare malignant tumor. The tumor is composed of both carcinomatous and sarcomatous elements. The multiple designations of names such as pseudosarcoma, pseudosarcomatous carcinoma, polypoid carcinoma etc. reflect the controversy on the nature of sarcomatous component of this lesion. We report a case of carcinosarcoma of esophagus occurred in a 67 year old male with progressive dysphagia. Esophageal polypoid tumor was found by endoscopy and was resected by esophagectomy. Carcinosarcoma was proved by demonstrating both carcinomatous and sarcomatous components in the tumor. Immunohistochemical studies revealed positive keratin stain in the sarcomatous area and positive vimentin stain in the sarcomatous area. The tumor was reported to have a better prognosis than that of the squamous cell carcinoma of esophagus in the literatures, especially in the survival rate.

Resolution of liver abscesses: comparison of pyogenic and amebic liver abscesses

To examine the resolution of liver abscesses, a prospective ultrasonographic follow-up study was conducted in 51 patients, each with a solitary abscess (26 pyogenic and 25 amebic) which had been treated successfully by non-surgical measures. The rate of complete abscess resolution for each of the initial 6 months was 0%, 5%, 10%, 23%, 30%, and 30% in the amebic group; and 20%, 54%, 77%, 89%, 94%, and 94% in the pyogenic group. The absorption volume of the pyogenic group in the first month was also greater than that of the amebic group (3.0 +/- 5.0 ml/day vs. 1.1 +/- 0.8 ml/day, P less than 0.05). The resolution ratio of pyogenic and amebic liver abscesses in the first month was 74% +/- 38% and 36% +/- 23%, respectively. In 3 patients in the amebic group, the abscess was still detectable 2 years after treatment. These results suggest that pyogenic liver abscesses resolve more rapidly than amebic abscesses. These findings should be considered in the differential diagnosis of asymptomatic space-taking lesion in the liver.

Antibody response to Epstein-Barr-virus-specific DNase in 13 patients with nasopharyngeal carcinoma in Taiwan: a retrospective study

Serum samples obtained from 13 individuals who were found to have a previous history of or to be suffering from nasopharyngeal carcinoma (NPC) were examined for the presence of antibody to Epstein-Barr virus (EBV) DNase activity. Significant to high levels of antibody to EBV DNase activity were detected in most serum samples obtained from four patients prior to the diagnosis of NPC. The samples from the other nine patients showed variable levels of antibody. The majority of the samples collected at the remission stage of the disease, especially those from long-term survivors, contained little or no antibody to the DNase activity. Data presented here suggest that antibody to EBV DNase activity may be a useful marker for the early diagnosis as well as the prognosis of NPC.

Geographic distribution of HBsAg carriers in China

We tested by radioimmunoassay the sera of 22,707 male Chinese government employees in Taiwan for HBsAg and found 15.2% to be positive. Almost all were confirmed as carriers by follow-up testing 1 year later. This paper presents HBsAg positivity rates of these men according to the province of China from which they originated, and compares the rates with published provincial mortality rates for primary hepatocellular carcinoma. Moderate variation in carrier rates between provinces was observed with high prevalence in men from provinces south of the Yangtze River. There was positive correlation between HBsAg prevalence and primary hepatocellular carcinoma incidence giving further support to the possibility of a causal relationship.