Telomere 3' overhang-specific DNA oligonucleotides (T-oligos) induce cell death in cancer cells, presumably by mimicking telomere loop disruption. Therefore, T-oligos are considered an exciting new ...therapeutic strategy. The purpose of this study was to elucidate how T-oligos exert antitumor effects on human malignant glioma cells @@iin vitro@ and @@iin vivo.@ We demonstrated that T-oligos inhibited the proliferation of malignant glioma cells through induction of nonapoptotic cell death and mitochondria hyperpolarization, whereas normal astrocytes were resistant to T-oligos. Tumor cells treated with T-oligos developed features compatible with autophagy, with development of autophagic vacuoles and conversion of an autophagy-related protein, microtubule-associated protein 1 light chain 3 from type I (cytoplasmic form) to type II (membrane form of autophagic vacuoles). A reverse-phase protein microarray analysis and Western blotting revealed that treatment with T-oligos inhibited the mammalian target of the rapamycin (mTOR) and the signal transducer and activator of transcription 3 (STAT3). Moreover, pretreatment with T-oligos significantly prolonged the survival time of mice inoculated intracranially with malignant glioma cells compared with that of untreated mice and those treated with control oligonucleotides (@iP=0.0065 and @iP=0.043, respectively). These results indicate that T-oligos stimulate the induction of nonapoptotic autophagic also known as type II programmed cell death and are thus promising in the treatment of malignant glioma.--Aoki, H., Iwado, E., Eller, M. S., Kondo, Y., Fujiwara, K., Li, G.-Z., Hess, K. R., Siwak, D. R., Sawaya, R., Mills, G. B., Gilchrest, B. A., Kondo, S. Telomere 3' overhang-specific DNA oligonucleotides induce autophagy in malignant glioma cells.
Two cases of intracranial metastatic malignant melanoma are reported. Both patients were males of sixties with known primary skin malignant melanomas. Magnetic resonance imagings showed intracranial ...lesions, which were high intense in T1 WI, low intense in T2 WI and enhanced after Gd-DTPA adminisration. These findings were characteristic for intracranial malignat melanomas. Treatment design consisted of intra-arterial chemotherapy with CDDP and ACNU, follwed by surgical resection and/or radiosurgery. In the first case, intratumoral hemorrhage occurred 40 hours after the intra-arterial chemotherapy and emergent craniotomy, instead of radiosurgery, was performed. The second patient underwent tumor removal on the following day after the chemotherapy. Both patients died of systemic metastases 2 and 3 months after the treatment, respectively. Malignant melanomas are prone to metastasize to any organs including brain. Patients with malignant melanoma usually have short life expectancy, so the aim of treatment is focused on the maintenance of the QOL as long as possible. So, vigorous treatment should be carried out whenever necessary. Finally, spontaneous hemorrhage into intracranial malignant melanoma have been frequently observed. As shown in our case 1, treatment modalities might enhanced the risk of intratumoral hemorrhage. Care should be taken to avoid this serious complication
Autophagy, an evolutionarily conserved response to stress, has recently been implicated in cancer initiation and progression, but the detailed mechanisms and functions have not yet been fully ...elucidated. One major obstacle to our understanding is lack of an efficient and robust method to specifically monitor autophagic cells in cancer specimens. To identify molecular events associated with autophagy, we performed cDNA microarray analysis of autophagic glioblastoma cell lines. Based on the analysis, we raised a polyclonal antibody against isoform B of human microtubule-associated protein 1 light chain 3 (LC3B). Application of the anti-LC3B antibody revealed the presence of autophagic cells in both in vitro and in vivo settings. Of the 65 glioblastoma tissues, 31 had highly positive cytoplasmic staining of LC3B. The statistical interaction between cytoplasmic staining of LC3B and Karnofsky Performance Scale score was significant. High expression of LC3B was associated with an improved outcome for patients with poorer performance, whereas, for patients with normal performance, survival was better for patients with low staining than with high staining of LC3B. Anti-LC3B antibody provides a useful tool for monitoring the induction of autophagy in cancer cells and tissues.
Objective To investigate the mechanisms of antiproliferative effect induced by the mammalian target of rapamycin (mTOR) inhibitor temsirolimus in mantle cell lymphoma (MCL). Materials and Methods The ...antiproliferative effect of temsirolimus on three well-defined MCL cell lines was examined by the MTS assay. Induction of cell-cycle arrest, autophagy, and apoptosis were determined by fluorescence-activated cell sorting analysis. The molecular mechanisms underlining these effects were determined by Western blot. Synergy between temsirolimus and vorinostat were examined by MTS assay and the combination index was calculated. Results Temsirolimus has antiproliferative activity in three MCL cell lines in a dose- and time-dependent manner. Mechanistically, temsirolimus inhibited mTOR, as evidenced by inhibition of ribosomal S6 phosphorylation, and induced cell-cycle arrest in the G0 /G1 phase and a decrease in p21 expression without altering p27 or cyclin D1 levels. Furthermore, temsirolimus increased the number of acidic vesicular organelles and the amount of microtubule-associated protein 1 light-chain 3 processing, which are characteristic of autophagy, without induction of apoptosis. These changes were not associated with alteration in phosphorylated extracellular signal-regulated kinase (ERK), beclin-1, Bax, or Bak levels. In contrast, treatment of these cell lines with the histone deacetylase inhibitor vorinostat decreased ERK phosphorylation, activated caspase 3, and induced apoptosis. Moreover, temsirolimus synergized with submaximal concentrations of vorinostat in all MCL cell lines. Conclusion This is the first report of temsirolimus-induced autophagy in MCL, and of vorinostat inhibition of ERK phosphorylation in MCL. Collectively, these data suggest that the combination of temsirolimus and vorinostat have synergistic antiproliferative activity in MCL cells by distinctively targeting apoptosis and autophagy.
Chronic cigarette smoking alters coronary vascular endothelial response. To determine whether altered response also occurs in young individuals without manifest coronary disease we quantified ...coronary blood flow at rest, following adenosine vasodilator stress and during the cold pressor test in healthy young smokers. Myocardial blood flow (MBF) was quantified by oxygen-15 labelled water positron emission tomography in 30 healthy men aged from 20 to 35 years (18 smokers and 12 non-smokers, aged 27.4 +/- 4.4 vs 26.3 +/- 3.3). The smokers had been smoking cigarettes for 9.4 +/- 4.9 pack-years. MBF was measured at rest, during intravenous adenosine triphosphate (ATP: 0.16 mg kg(-1) min(-1)) infusion (hyperaemic response), and during cold pressor test (CPT) (endothelial vasodilator response). Rest MBF and hyperaemic MBF did not differ significantly between the smokers and the non-smokers (rest: 0.86 +/- 0.11 vs 0.92 +/- 0.14 and ATP: 3.20 +/- 1.12 vs 3.69 +/- 0.76 ml g(-1) min(-1); P = NS). Coronary flow reserve was similar between the two groups (smokers: 3.78 +/- 1.83; non-smokers: 4.03 +/- 0.68; P = NS). Although CPT induced a similar increase in rate-pressure product (RPP) in the smokers and the non-smokers (10,430 +/- 1,820 vs 9,236 +/- 1,356 beats min(-1) mmHg(-1)), CPT MBF corrected by RPP was significantly decreased in the smokers (0.65 +/- 0.12 ml g(-1) min(-1)) compared with the non-smokers (0.87 +/- 0.12 ml g(-1) min(-1)) ( P < 0.05). In addition, the ratio of CPT MBF to resting MBF was inversely correlated with pack-years ( r = -0.57, P = 0.014). Endothelium-dependent coronary artery vasodilator function is impaired in apparently healthy young smokers.
In ischaemic heart disease patients, transient left ventricular dysfunction is observed due to post-exercise stunning. The aim of this study was to determine whether transient left ventricular ...dysfunction could also be seen after short-acting pharmacological stress (adenosine triphosphate). A 1 day rest/stress gated myocardial single photon emission computed tomography was performed on 362 patients suspected of having ischaemic heart disease by exercise (n = 199) or short-acting pharmacological stress (n = 163). Left ventricular ejection fraction were estimated both at rest and stress. Based on perfusion findings, patients were subdivided into ischaemia, fixed defect and normal group. For the ischaemia and fixed defect group, left ventricular ejection fraction after stress was significantly decreased compared with the resting value by exercise stress (ischaemia group, 57.5±11.0 vs 60.4±10.4; fixed defect group, 47.7±16.7 vs 49.6±16.8; P<0.01), but not by pharmacological stress (ischaemia group, 55.8±13.4 vs 57.1±13.8; fixed defect group, 50.8±13.5 vs 50.6±13.1; P = NS). In the normal group, left ventricular ejection fraction after stress was not significantly changed by either exercise (65.7±10.4 vs 66.8±10.2; P = NS) or pharmacological stress (63.0±11.7 vs 64.0±12.1; P = NS). It is concluded that a transient decrease in left ventricular ejection fraction after stress was observed following post-exercise, not following a short-acting pharmacological stress in patients showing perfusion abnormalities. Transient left ventricular dysfunction may be the result of post-exercise stunning, not from subendocardial hypoperfusion induced by short-acting pharmacological stress.
PDF
