Protein kinase C inhibitor and irradiation-induced apoptosis: Relevance of the cytochrome c-mediated caspase-9 death pathway

Caspases are a family of cysteine proteases that constitute the apoptotic cell death machinery, We report the importance of the cytochrome c-mediated caspase-9 death pathway for radiosensitization by the protein kinase C (PKC) inhibitors staurosporine (STP) and PKC-412. In our genetically defined tumor cells, treatment with low doses of STP or the conventional PKC-specific inhibitor PKC-412 in combination with irradiation (5 Gy) potently reduced viability, enhanced mitochondrial cytochrome c release into the cytosol, and specifically stimulated the initiator caspase-9. Whereas treatment with each agent alone had a minimal effect, combined treatment resulted in enhanced caspase-3 activation. This was prevented by broad-range and specific caspase-9 inhibitors and absent in caspase-9-deficient cells. The tumor suppressor p53 was required for apoptosis induction by combined treatment but was dispensable for dose-dependent STP-induced caspase activation. These results demonstrate the requirement for an intact caspase-9 pathway for apoptosis-based radiosensitization by PKC inhibitors and show that STP induces apoptosis independent of p53

Locoregional failure analysis in head-and-neck cancer patients treated with IMRT

PURPOSE: Analysis of locoregional failure in head-and-neck cancer (HNC) following intensity-modulated radiation therapy (IMRT), with focus on the location of locoregional failures in relation to the chosen planning target volumes (PTVs) and dose distributions. PATIENTS AND METHODS: Between January 2002 and May 2006, 280 HNC patients were subjected to IMRT at the authors' institution. Mean follow-up was 23.2 months (3-59.3 months). Definitive IMRT was performed in 75% of all patients. In 71%, simultaneous cisplatin-based chemotherapy was given. 70% of patients presented with T3/4, T1-2 N2c/3 or recurred disease. Locoregional failure patterns were analyzed. RESULTS: 2-year local, nodal, distant, disease-free, and overall survival rates were 80%, 87%, 87%, 73%, and 82%, respectively. 46 local (16%) and 31 nodal (11%) failures have been observed so far. Local tumor persistence was seen in 23/46 cases (50%), and nodal persistence in 12/31 (39%), respectively. One marginal local failure developed in a patient referred for a recurred oral cavity tumor. Three nodal failures developed outside the PTVs at unexpected locations. All other failures have been confirmed "in field". No failure occurred in level Ib or upper level II. Local failure occurred mainly following definitive IMRT for large tumors, nodal failure only in nodally positive patients with nodal high-risk features. CONCLUSION: The dose-volume concept as used here has shown to be adequate, with disease failure developing at the site of the initial gross tumor manifestation inside the boost volume

Protective films on complex substrates of thermoplastic and cellular elastomers:Prospective applications to rubber, nylon and cork

Deposition of thin films is an appropriate methodology to enhance the performance of a material by modification of its surface, while keeping the properties of the bulk largely unaffected. However, a practical implementation becomes less straightforward when dealing with sensitive or complex substrates, for instance, those which cannot be subjected to harsh treatments, such as cleaning and etching, or extreme deposition conditions, like high temperatures, and ion impingement et cetera. This paper concentrates on deposition processing of complex substrates. In particular, it discusses the deposition of two types of protective coatings (diamond-like carbon (DLC) films against friction and wear, and TiO2 films against UV light) on three types of thermoplastic and cellular elastomers (rubber, nylon and cork). It is demonstrated that a successful protection of thermoplastic elastomers against wear with DLC films can be attained, after a thorough adaptation of the procedure to the characteristics of the specific substrate. In addition, the paper reports the very first depositions on a cellular elastomer like cork by vapor deposition methods, including Atomic Layer Deposition (ALD)

PET/CT Staging Followed by Intensity-Modulated Radiotherapy (IMRT) Improves Treatment Outcome of Locally Advanced Pharyngeal Carcinoma: a matched-pair comparison

BACKGROUND: Impact of non-pharmacological innovations on cancer cure rates is difficult to assess. It remains unclear, whether outcome improves with 2- [18-F]-fluoro-2-deoxyglucose-positron emission tomography and integrated computer tomography (PET/CT) and intensity-modulated radiotherapy (IMRT) for curative treatment of advanced pharyngeal carcinoma. PATIENTS AND METHODS: Forty five patients with stage IVA oro- or hypopharyngeal carcinoma were staged with an integrated PET/CT and treated with definitive chemoradiation with IMRT from 2002 until 2005. To estimate the impact of PET/CT with IMRT on outcome, a case-control analysis on all patients with PET/CT and IMRT was done after matching with eighty six patients treated between 1991 and 2001 without PET/CT and 3D-conformal radiotherapy with respect to gender, age, stage, grade, and tumor location with a ratio of 1:2. Median follow-up was eighteen months (range, 6-49 months) for the PET/CT-IMRT group and twenty eight months (range, 1-168 months) for the controls. RESULTS: PET/CT and treatment with IMRT improved cure rates compared to patients without PET/CT and IMRT. Overall survival of patients with PET/CT and IMRT was 97% and 91% at 1 and 2 years respectively, compared to 74% and 54% for patients without PET/CT or IMRT (p = 0.002). The event-free survival rate of PET/CT-IMRT group was 90% and 80% at 1 and 2 years respectively, compared to 72% and 56% in the control group (p = 0.005). CONCLUSION: PET/CT in combination with IMRT and chemotherapy for pharyngeal carcinoma improve oncological therapy of pharyngeal carcinomas. Long-term follow-up is needed to confirm these findings

Effect of VEGF receptor inhibitor PTK787/ZK222548 combined with ionizing radiation on endothelial cells and tumour growth

The vascular endothelial growth factor (VEGF) receptor is a major target for anti-angiogenesis-based cancer treatment. Here we report the treatment effect of ionizing radiation in combination with the novel orally bioavailable VEGF receptor tyrosine kinase inhibitor PTK787/ZK222584 on endothelial cell proliferation in vitro and with tumour xenografts in vivo. Combined treatment of human umbilical vein endothelial cells with increasing doses of PTK787/ZK222584 and ionizing radiation abrogated VEGF-dependent proliferation in a dose-dependent way, but inhibition of endothelial cell proliferation was not due to apoptosis induction. In vivo, a combined treatment regimen of PTK787/ZK222584 (4 × 100 mg/kg) during 4 consecutive days in combination with ionizing radiation (4 × 3 Gy) exerted a substantial tumour growth delay for radiation-resistant p53-disfunctional tumour xenografts derived from SW480 colon adenocarcinoma cells while each treatment modality alone had only a minimal effect on tumour size and neovascularization. SW480 tumours from animals that received a combined treatment regimen, displayed not only an extended tumour growth delay but also a significant decrease in the number of microvessels in the tumour xenograft. These results support the model of a cooperative antitumoural effect of angiogenesis inhibitor and irradiation and show that the orally bioavailable VEGF receptor tyrosine kinase inhibitor PTK787/ZK222584 is suitable for combination therapy with irradiation. © 2001 Cancer Research Campaign http://www.bjcancer.co

Uptake and localisation of mTHPC (Foscan®) and its14C-labelled form in normal and tumour tissues of the hamster squamous cell carcinoma model: a comparative study

The aim of this study was to evaluate the pharmacokinetics of meta(tetrahydroxyphenyl)chlorin (mTHPC) on different tissues of interest in a hamster tumour model and to confirm our earlier animal studies on semi-quantitative fluorescence microscopy. The results obtained by three different evaluation methods were compared: in vivo spectrofluorometry, ex vivo fluorescence microscopy and chemical extraction of 14C-labelled mTHPC. Following intracardiac injection of 0.5 mg kg−1 mTHPC, groups of five tumour-bearing animals were used for in situ light-induced fluorescence spectroscopy. Afterwards, the biopsies were taken and snap frozen for fluorescence microscopy. The presence of radioactivity in serum and tissues was determined after chemical digestion in scintillation fluid using a scintillation counter. For each analysed tissue, a good correlation was observed between the three evaluation methods. The highest fluorescence intensity and quantities of mTHPC were observed between 12 and 24 h in liver, kidney, serum, vascular endothelium and advanced neoplasia. The majority of mTHPC was found at around 48 h in smooth muscle and at 96 h in healthy cheek pouch mucosa and early malignant lesions. The lowest level of mTHPC was noted in striated muscle at all times. No selectivity in dye localisation was observed between early squamous cell carcinoma and healthy mucosa. Soon after the injection, a significant selectivity was noted for advanced squamous cell carcinoma as compared to healthy cheek pouch mucosa or striated muscle. A significant difference in mTHPC localisation and quantity was also observed between striated and smooth muscle during the first 48 h following the injection. Finally, this study demonstrated the usefulness of non-invasive in situ spectroscopic measurements to be performed systematically prior to photodynamic therapy as a real-time monitoring for each treated patient in order to individualise and adapt the light dosimetry and avoid over or under treatments

Ticagrelor, but not clopidogrel, reduces arterial thrombosis via endothelial tissue factor suppression

The P2Y12 antagonist ticagrelor reduces mortality in patients with acute coronary syndrome (ACS), compared with clopidogrel, and the mechanisms underlying this effect are not clearly understood. Arterial thrombosis is the key event in ACS; however, direct vascular effects of either ticagrelor or clopidogrel with focus on arterial thrombosis and its key trigger tissue factor have not been previously investigated.Methods and results: Human aortic endothelial cells were treated with ticagrelor or clopidogrel active metabolite (CAM) and stimulated with tumour necrosis factor-alpha (TNF-α); effects on procoagulant tissue factor (TF) expression and activity, its counter-player TF pathway inhibitor (TFPI) and the underlying mechanisms were determined. Further, arterial thrombosis by photochemical injury of the common carotid artery, and TF expression in the murine endothelium were examined in C57BL/6 mice treated with ticagrelor or clopidogrel. Ticagrelor, but not CAM, reduced TNF-α-induced TF expression via proteasomal degradation and TF activity, independently of the P2Y12 receptor and the equilibrative nucleoside transporter 1 (ENT1), an additional target of ticagrelor. In C57BL/6 mice, ticagrelor prolonged time to arterial occlusion, compared with clopidogrel, despite comparable antiplatelet effects. In line with our in vitro results, ticagrelor, but not clopidogrel, reduced TF expression in the endothelium of murine arteries.Conclusion: Ticagrelor, unlike clopidogrel, exhibits endothelial-specific antithrombotic properties and blunts arterial thrombus formation. The additional antithrombotic properties displayed by ticagrelor may explain its greater efficacy in reducing thrombotic events in clinical trials. These findings may provide the basis for new indications for ticagrelor

Caracterização físico-química de nanopartículas de dióxido de titânio para produção de nanocompósitos.

A percepção de que animais também sentem medo dor e angústia leva a necessidade de desenvolvimento de inúmeros métodos alternativos ao uso de animais em experimentação. Assim, métodos in vitro são uma alternativa para contornar este problema. Baseado em sua biocompatibilidade e sua baixa toxicidade, as nanopartículas de dióxido de titânio (TiO2NPs) apresentam grande potencial para serem utilizadas na produção de desenvolvimento de matrizes 3D para a bioengenharia de tecidos. Dentro deste contexto, o presente trabalho tem por objetivo caracterizar fisicoquimicamente TiO2NPs para em um futuro utilizá-las para produção de nanocompósitos. Para tanto, TiO2NPs (NM01001a, European Union reference material) foram caracterizadas por técnicas espectroscópica (Raman e Infravermelho), bem como por microscopia de força atômica e espalhamento dinâmico de luz. As TiO2NPs apresentaram geometrias e tamanhos heterogêneos, contudo apresentando pelo menos um dos eixos cardinais com tamanho inferior a 100nm, elevado Índice de Dispersão (0,526 ± 0,05) e baixa estabilidade coloidal (potencial Zeta de -3,50 ± 0.40 mV). Por sua vez, o material apresentou indicativo de elevado grau de preza, com bandas características de ligações de Ti-O e grupos OH na superfície da partícula, respectivamente em 542 e 686 cm− 1 3427 cm− 1 na espectroscopia e infravermelho e 639, 517 e 395 cm− 1 espectroscopia Raman. Baseado nos resultados encontrados, pode-se concluir que as TiO2NPs apresentam elevado grau de pureza e caráter nanométrico com formato heterogêneo. Baseado em dados de literatura que relatam toxicidade em função da forma de nanopartículas, recomenda-se a realização recomenda-se a realização de mais estudos de toxicidade antes de seu uso em nanocompositos destinados a bioengenharia

Postoperative IMRT in head and neck cancer

BACKGROUND: Aim of this work was to assess loco-regional disease control in head and neck cancer (HNC) patients treated with postoperative intensity modulated radiation therapy (pIMRT). For comparative purposes, risk features of our series have been analysed with respect to histopathologic adverse factors. Results were compared with an own historic conventional radiation (3DCRT) series, and with 3DCRT and pIMRT data from other centres. Between January 2002 and August 2006, 71 patients were consecutively treated with pIMRT for a squamous cell carcinoma (SCC) of the oropharynx (32), oral cavity (22), hypopharynx (7), larynx (6), paranasal sinus (3), and an unknown primary, respectively. Mean and median follow up was 19 months (2–48), and 17.6 months. 83% were treated with IMRT-chemotherapy. Mean prescribed dose was 66.3 Gy (60–70), delivered with doses per fraction of 2–2.3 Gy, respectively. RESULTS: 2-year local, nodal, and distant control rates were 95%, 91%, and 96%, disease free and overall survival 90% and 83%, respectively. The corresponding survival rates for the subgroup of patients with a follow up time >12 months (n = 43) were 98%, 95%, 98%, 93%, and 88%, respectively. Distribution according to histopathologic risk features revealed 15% and 85% patients with intermediate and high risk, respectively. All loco-regional events occurred in the high risk subgroup. CONCLUSION: Surgery followed by postoperative IMRT in patients with substantial risk for recurrence resulted in high loco-regional tumor control rates compared with large prospective 3DCRT trials