Regorafenib enhances anti-PD1 immunotherapy efficacy in murine colorectal cancers and their combination prevents tumor regrowth

Background!#!Patients with advanced colorectal cancer (CRC) have a poor prognosis. Combinations of immunotherapies and anti-angiogenic agents are currently being evaluated in clinical trials. In this study, the multikinase inhibitor regorafenib (REG) was combined with an anti-programmed cell death protein 1 (aPD1) antibody in syngeneic murine microsatellite-stable (MSS) CT26 and hypermutated MC38 colon cancer models to gain mechanistic insights into potential drug synergism.!##!Methods!#!Growth and progression of orthotopic CT26 and subcutaneous MC38 colon cancers were studied under treatment with varying doses of REG and aPD1 alone or in combination. Sustained effects were studied after treatment discontinuation. Changes in the tumor microenvironment were assessed by dynamic contrast-enhanced MRI, and histological and molecular analyses.!##!Results!#!In both models, REG and aPD1 combination therapy significantly improved anti-tumor activity compared with single agents. However, in the CT26 model, the additive benefit of aPD1 only became apparent after treatment cessation. The combination treatment efficiently prevented tumor regrowth and completely suppressed liver metastasis, whereas the anti-tumorigenic effects of REG alone were abrogated soon after drug discontinuation. During treatment, REG significantly reduced the infiltration of immunosuppressive macrophages and regulatory T (Treg) cells into the tumor microenvironment. aPD1 significantly enhanced intratumoral IFNγ levels. The drugs synergized to induce sustained M1 polarization and durable reduction of Treg cells, which can explain the sustained tumor suppression.!##!Conclusions!#!This study highlights the synergistic immunomodulatory effects of REG and aPD1 combination therapy in mediating a sustained inhibition of colon cancer regrowth, strongly warranting clinical evaluation in CRC, including MSS tumors

Characterisation of resistance mechanisms to Erysiphe pisi in Medicago truncatula

5 pp.In this work, we studied the resistance of 277 Medicago truncatula accessions against powdery mildew and further characterized the defense mechanisms of resistant plants. Ten resistant accessions were selected according to macroscopic assessment. Histological studies showed a range of defense mechanisms, acting alone or combined, that impeded fungal development at different stages. Some accessions allowed a reduced spore germination frequency compared with that of the susceptible control. In others, the fungus was arrested at penetration stage due to papilla formation. Epidermal cells of several accessions were penetrated by the fungus but then hypersensitive response (HR) leading to cell death hampered fungal development. In some cases, cell death was very fast and no haustorium could be observed in epidermal cells, whereas in others, haustoria and secondary hyphae indicated a slow HR. Finally, in some accessions in which no HR was observed, colony growth was restricted through posthaustorial defense mechanisms. Characterization of defense mechanisms will be useful for further cellular and molecular studies to unravel the bases of resistance in this species in particular and in legume-powdery mildew interaction in general.INIST-CNRS, Cote INISTPeer reviewe

Molecular Ultrasound Imaging Depicts the Modulation of Tumor Angiogenesis by Acetylsalicylic Acid

Acetylsalicylic acid (ASA) is a well-established drug for heart attack and stroke prophylaxis. Furthermore, numerous studies have reported an anti-carcinogenic effect, but its exact mechanism is still unknown. Here, we applied VEGFR-2-targeted molecular ultrasound to explore a potential inhibitory effect of ASA on tumor angiogenesis in vivo. Daily ASA or placebo therapy was performed in a 4T1 tumor mouse model. During therapy, ultrasound scans were performed using nonspecific microbubbles (CEUS) to determine the relative intratumoral blood volume (rBV) and VEGFR-2-targeted microbubbles to assess angiogenesis. Finally, vessel density and VEGFR-2 expression were assessed histologically. CEUS indicated a decreasing rBV in both groups over time. VEGFR-2 expression increased in both groups up to Day 7. Towards Day 11, the binding of VEGFR-2-specific microbubbles further increased in controls, but significantly (p = 0.0015) decreased under ASA therapy (2.24 ± 0.46 au vs. 0.54 ± 0.55 au). Immunofluorescence showed a tendency towards lower vessel density under ASA and confirmed the result of molecular ultrasound. Molecular US demonstrated an inhibitory effect of ASA on VEGFR-2 expression accompanied by a tendency towards lower vessel density. Thus, this study suggests the inhibition of angiogenesis via VEGFR-2 downregulation as one of the anti-tumor effects of ASA

Optical Tomography of MMP Activity Allows a Sensitive Noninvasive Characterization of the Invasiveness and Angiogenesis of SCC Xenografts

AbstractFor improved tumor staging and therapy control, imaging biomarkers are of great interest allowing a noninvasive characterization of invasiveness. In squamous epithelial skin and cervix lesions, transition to invasive stages is associated with enhanced matrix metalloproteinase (MMP) activity, increased angiogenesis, and worsened prognosis. Thus, we investigated MMP activity as imaging biomarker of invasiveness and the potential of optical tomography in characterizing the angiogenic and invasive behavior of skin squamous cell carcinoma (SCC) xenografts. MMP activity was measured in vivo in HaCaT-ras A-5RT3 tumors at different angiogenic and invasive stages (onset of angiogenesis, intermediate and highly angiogenic, invasive stage) and after 1 week of sunitinib treatment by fluorescence molecular tomography–microcomputed tomography imaging using an activatable probe. Treatment response was additionally assessed morphologically by optical coherence tomography (OCT). In vivo MMP activity significantly differed between the groups, revealing highest levels in the highly angiogenic, invasive tumors that were confirmed by immunohistochemistry. At the onset of angiogenesis with lowest MMP activity, fibroblasts were detected in the MMP-positive areas, whereas macrophages were absent. Accumulation of both cell types occurred in both invasive groups, again to a significantly higher degree at the most invasive and angiogenic stage. Sunitinib treatment significantly reduced the MMP activity and accumulation of fibroblasts and macrophages and blocked tumor invasion that was additionally visualized by OCT. Human cervical SCCs also showed high MMP activity and a similar stromal composition as the HaCaT xenografts, whereas normal tissue was negative. This study strongly suggests MMP activity as imaging biomarker and demonstrates the high sensitivity of optical tomography in determining tumor invasiveness that can morphologically be supported by OCT

Increase of trouble-free operation and electrical safety level of distributive networks by a voltage 6-35 kV of open cast mines.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.09.03 – "Електротехнічні комплекси та системи". – Державний виший навчальний заклад "Національний гірничий університет", Дніпропетровськ, 2012.Диссертация на соискание ученой степени кандидата технических наук по специальности 05.09.03 – "Электротехнические комплексы и системы". – Государственное высшее учебное заведение "Национальный горный университет", Днепропетровск, 2012.Thesis for a candidate of technical science degree by speciality 05.09.03 – "Electrotechnical complexes and systems". State institution of higher education “National Mining University” subject to the Ministry of Education and Science, Youth and Sports of Ukraine, Dnipropetrovs’k, 2012.Дисертація присвячена розробці принципів і технічних засобів підвищення рівня експлуатаційної надійності і поліпшенню умов електробезпеки в системах електропостачання кар'єрів. Дана характеристика системам електропостачання сучасних залізорудних кар’єрів, розглянуто особливості експлуатації електричних розподільних мереж, виконано аналіз методів контролю ізоляції та засобів захисту. Представлені результати досліджень впливу режиму нейтралі кар'єрних розподільних мереж на якісні та кількісні параметри усталеного і перехідних процесів при замиканнях на землю. З порівняння варіантів заземлення нейтралі встановлено, що найбільш висока експлуатаційна надійність забезпечується в розподільних мережах з резистором в нейтралі. Дано теоретичне обґрунтування методу непрямої оцінки параметрів провідності ізоляції розподільних мереж напругою 6 кВ без зняття робочої напруги. Подані результати дослідження впливу параметрів режиму заземлення нейтралі на працездатність захистів від замикань на землю і на умови електробезпеки. Наведені технічні рішення та рекомендації, що забезпечують підвищення рівня безаварійності та електробезпеки розподільних і живлячих мереж кар'єрів.Диссертация посвящена разработке принципов и технических средств повышения уровня эксплуатационной надежности и улучшению условий электробезопасности в системах электроснабжения карьеров. Данная характеристика системам электроснабжения современных железорудных карьеров, рассмотрена особенности эксплуатации электрических распределительных сетей, выполнен анализ методов контроля изоляции и средств защиты. Представлены результаты исследований влияния режима заземления нейтрали карьерных распределительных сетей на качественные и количественные параметры установившихся и переходных процессов при замыканиях на землю. Из сравнения вариантов заземления нейтрали установлено, что наиболее высокая эксплуатационная надежность обеспечивается в распределительных сетях с резистором в нейтрали. Дано теоретическое обоснование метода косвенной оценки параметров проводимости изоляции распределительных сетей напряжением 6 кВ без снятия рабочего напряжения, основанного на искусственном изменении величины напряжения смещения нейтрали путем последовательного включения дополнительных тарированных активных проводимостей во все три фазы электроустановки в заданной последовательности. Представлены результаты исследования влияния параметров режима заземления нейтрали на работоспособность защит от замыканий на землю и на условия электробезопасности. Для компенсированных сетей при отсутствии автоматической резонансной настройки режима компенсации рекомендован комбинированный режим заземления нейтрали, который обеспечивает эксплуатационные показатели адекватные системам электроснабжения только с резистором в нейтрали даже при расстройках дугогасящего реактора до 50% от резонансного режима. Показано, что по степени косвенной опасности электрических сетей, работающих с разными режимами нейтрали, предпочтение следует отдать электрическим сетям с резистором в нейтрали. Приведены разработанные технические решения и рекомендации, которые обеспечивают повышение уровня безаварийности и электробезопасности распределительных и живящих сетей карьеров: структура и алгоритм автоматизации процесса косвенного определения полных проводимостей изоляции фаз и их составляющих в трехфазных электрических сетях с изолированной нейтралью напряжением 6-35 кВ с любой степенью несимметрии изоляции; рекомендации по обеспечению селективности защит от замыканий на землю на питающих КРП линиях при двухступенчатой структуре карьерных распределительных сетей; функциональная схема системы избирательной защиты для разветвленных распределительных сетей с компенсированной нейтралью.The thesis is devoted to development of principles and technical means of increase of an operational reliability level and improvement of electrical safety conditions in power supply systems of open cast mines. The characteristic of power supply systems of modern open cast iron mines is given, the peculiarities of electrical distributive networks operation are considered, the analysis of insulation control methods and protection means are performed. The investigation results of neutral mode influence of open cast mining distributive networks on qualitative and quantitative parameters of steady and transient process in the time of ground fault are presented. From the comparison of neutral grounding options it is determined that highest operational reliability is ensured in distributive networks with resistor in neutral. The theoretical justification of indirect estimation method of insulation conductivity parameters of distributive networks by a voltage 6 kV without switching-off of a working voltage is given. The investigation results of grounding neutral mode parameters influence on the operability of ground fault protection and electrical safety conditions are given. The technical solutions and recommendations that provide the level increase of trouble-free operation and electrical safety of distributive and supplying networks of open cast mines are presented

Nilotinib Enhances Tumor Angiogenesis and Counteracts VEGFR2 Blockade in an Orthotopic Breast Cancer Xenograft Model with Desmoplastic Response

Vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR)-targeted therapies predominantly affect nascent, immature tumor vessels. Since platelet-derived growth factor receptor (PDGFR) blockade inhibits vessel maturation and thus increases the amount of immature tumor vessels, we evaluated whether the combined PDGFR inhibition by nilotinib and VEGFR2 blockade by DC101 has synergistic therapy effects in a desmoplastic breast cancer xenograft model. In this context, besides immunohistological evaluation, molecular ultrasound imaging with BR55, the clinically used VEGFR2-targeted microbubbles, was applied to monitor VEGFR2-positive vessels noninvasively and to assess the therapy effects on tumor angiogenesis. DC101 treatment alone inhibited tumor angiogenesis, resulting in lower tumor growth and in significantly lower vessel density than in the control group after 14 days of therapy. In contrast, nilotinib inhibited vessel maturation but enhanced VEGFR2 expression, leading to markedly increased tumor volumes and a significantly higher vessel density. The combination of both drugs led to an almost similar tumor growth as in the DC101 treatment group, but VEGFR2 expression and microvessel density were higher and comparable to the controls. Further analyses revealed significantly higher levels of tumor cell–derived VEGF in nilotinib-treated tumors. In line with this, nilotinib, especially in low doses, induced an upregulation of VEGF and IL-6 mRNA in the tumor cells in vitro, thus providing an explanation for the enhanced angiogenesis observed in nilotinib-treated tumors in vivo. These findings suggest that nilotinib inhibits vessel maturation but counteracts the effects of antiangiogenic co-therapy by enhancing VEGF expression by the tumor cells and stimulating tumor angiogenesis