Preclinical evaluation of cancer immune therapy using patient-derived tumor antigen-specific T cells in a novel xenograft platform.

Objectives: With a rapidly growing list of candidate immune-based cancer therapeutics, there is a critical need to generate highly reliable animal models to preclinically evaluate the efficacy of emerging immune-based therapies, facilitating successful clinical translation. Our aim was to design and validate a novel Methods: Tumor xenografts are established rapidly in the greater omentum of globally immunodeficient NOD- Results: The tumors progress rapidly and disseminate in the mice unless patient-derived tumor-specific T cells are introduced. An initial T cell-mediated tumor arrest is later followed by a tumor escape, which correlates with the upregulation of the checkpoint molecules programmed cell death-1 (PD-1) and lymphocyte-activation gene 3 (LAG3) on T cells. Treatment with immune-based therapies that target these checkpoints, such as anti-PD-1 antibody (nivolumab) or interleukin-12 (IL-12), prevented or delayed the tumor escape. Furthermore, IL-12 treatment suppressed PD-1 and LAG3 upregulation on T cells. Conclusion: Together, these results validate the X-mouse model and establish its potential to preclinically evaluate the therapeutic efficacy of immune-based therapies

Novel phosphatidylserine-binding molecule enhances antitumor T-cell responses by targeting immunosuppressive exosomes in human tumor microenvironments.

BACKGROUND: The human tumor microenvironment (TME) is a complex and dynamic milieu of diverse acellular and cellular components, creating an immunosuppressive environment, which contributes to tumor progression. We have previously shown that phosphatidylserine (PS) expressed on the surface of exosomes isolated from human TMEs is causally linked to T-cell immunosuppression, representing a potential immunotherapeutic target. In this study, we investigated the effect of ExoBlock, a novel PS-binding molecule, on T-cell responses in the TME. METHODS: We designed and synthesized a new compound, (ZnDPA) RESULTS: ExoBlock was able to bind PS with high avidity and was found to consistently and significantly block the immunosuppressive activity of human ovarian tumor and melanoma-associated exosomes in vitro. ExoBlock was also able to significantly enhance T cell-mediated tumor suppression in vivo in both the X-mouse and the OTX model. In the X-mouse model, ExoBlock suppressed tumor recurrence in a T cell-dependent manner. In the OTX model, ExoBlock treatment resulted in an increase in the number as well as function of CD4 and CD8 T cells in the TME, which was associated with a reduction in tumor burden and metastasis, as well as in the number of circulating PS+ exosomes in tumor-bearing mice. CONCLUSION: Our results establish that targeting exosomal PS in TMEs with ExoBlock represents a promising strategy to enhance antitumor T-cell responses

The Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX): overview and preliminary results

While the demand for enhancing rainfall through cloud seeding is strong and persistent in the country, considerable uncertainty exists on the success of such an endeavour at a given location. To understand the pathways of aerosol-cloud interaction through which this might be achieved, a national experiment named Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) in two phases, was carried out. The rationale of CAIPEEX, the strategy for conducting the experiment, data quality and potential for path-breaking science are described in this article. Pending completion of quality control and calibration of the CAIPEEX phase-II data, here we present some initial results of CAIPEEX phase-I aimed at documenting the prevailing microphysical characteristics of aerosols and clouds and associated environmental conditions over different regions of the country and under different monsoon conditions with the help of an instrumented research aircraft. First-time simultaneous observations of aerosol, cloud condensation nuclei (CCN) and cloud droplet number concentration (CDNC) over the Ganges Valley during monsoon season show very high concentrations (> 1000 cm-3) of CCN at elevated layers. Observations of elevated layers with high aerosol concentration over the Gangetic valley extending up to 6 km and relatively less aerosol concentration in the boundary layer are also documented. We also present evidence of strong cloud- aerosol interaction in the moist environments with an increase in the cloud droplet effective radius. Our observations also show that pollution increases CDNC and the warm rain depth, and delays its initiation. The critical effective radius for warm rain initiation is found to be between 10 and 12 µm in the polluted clouds and it is between 12 and 14 µm in cleaner monsoon clouds

Humanized Mouse Model of Ovarian Cancer Recapitulates Patient Solid Tumor Progression, Ascites Formation, and Metastasis

Ovarian cancer is the most common cause of death from gynecological cancer. Understanding the biology of this disease, particularly how tumor-associated lymphocytes and fibroblasts contribute to the progression and metastasis of the tumor, has been impeded by the lack of a suitable tumor xenograft model. We report a simple and reproducible system in which the tumor and tumor stroma are successfully engrafted into NOD-scid IL2Rγnull (NSG) mice. This is achieved by injecting tumor cell aggregates derived from fresh ovarian tumor biopsy tissues (including tumor cells, and tumor-associated lymphocytes and fibroblasts) i.p. into NSG mice. Tumor progression in these mice closely parallels many of the events that are observed in ovarian cancer patients. Tumors establish in the omentum, ovaries, liver, spleen, uterus, and pancreas. Tumor growth is initially very slow and progressive within the peritoneal cavity with an ultimate development of tumor ascites, spontaneous metastasis to the lung, increasing serum and ascites levels of CA125, and the retention of tumor-associated human fibroblasts and lymphocytes that remain functional and responsive to cytokines for prolonged periods. With this model one will be able to determine how fibroblasts and lymphocytes within the tumor microenvironment may contribute to tumor growth and metastasis, and will make it possible to evaluate the efficacy of therapies that are designed to target these cells in the tumor stroma

Engineering large cartilage tissues using dynamic bioreactor culture at defined oxygen conditions

Mesenchymal stem cells maintained in appropriate culture conditions are capable of producing robust cartilage tissue. However, gradients in nutrient availability that arise during three-dimensional culture can result in the development of spatially inhomogeneous cartilage tissues with core regions devoid of matrix. Previous attempts at developing dynamic culture systems to overcome these limitations have reported suppression of mesenchymal stem cell chondrogenesis compared to static conditions. We hypothesize that by modulating oxygen availability during bioreactor culture, it is possible to engineer cartilage tissues of scale. The objective of this study was to determine whether dynamic bioreactor culture, at defined oxygen conditions, could facilitate the development of large, spatially homogeneous cartilage tissues using mesenchymal stem cell laden hydrogels. A dynamic culture regime was directly compared to static conditions for its capacity to support chondrogenesis of mesenchymal stem cells in both small and large alginate hydrogels. The influence of external oxygen tension on the response to the dynamic culture conditions was explored by performing the experiment at 20% O 2 and 3% O 2 . At 20% O 2 , dynamic culture significantly suppressed chondrogenesis in engineered tissues of all sizes. In contrast, at 3% O 2 dynamic culture significantly enhanced the distribution and amount of cartilage matrix components (sulphated glycosaminoglycan and collagen II) in larger constructs compared to static conditions. Taken together, these results demonstrate that dynamic culture regimes that provide adequate nutrient availability and a low oxygen environment can be employed to engineer large homogeneous cartilage tissues. Such culture systems could facilitate the scaling up of cartilage tissue engineering strategies towards clinically relevant dimensions

Oceansat-1 derived met-ocean parameters during various stages of monsoon depression of June 1999, along Orissa coastline, east coast of India

113-121After the launch of Oceansat-1 (IRS-P4) on May 26, 1999, weather scientists got the opportunity to study some of the meteorological and oceanographic (met-ocean) parameters associated with the weather systems formed over the oceanic regions around India, even under cloudy conditions. Oceansat-1 carries multifrequency scanning microwave radiometer (MSMR) which has a capability to provide information of certain parameters viz. sea surface wind speeds (SSW), sea surface temperature (SST), integrated water vapour (IWV) and cloud liquid water content (CLW). A monsoon depression was formed over the Bay of Bengal on 17 June 1999 causing widespread rainfall over Orissa coast and the adjoining regions. Oceansat-1 derived met-ocean parameters were studied during various stages of this depression. The maximum values of these parameters during the life cycle of the depression over the Bay of Bengal were SST : 30º - 31º C, SSW : 16-18 m/s, IWV : 7.0 g/cm², CLW : 90-100 mg/cm². It was observed that SSW, IWV and CLW show high values one to three days before the formation of the depression. High values, shape and steep gradients of the met-ocean parameters give prior indication of formation/intensification of the weather system and its probable location. SST reduced by about 1º-2º after the passage of the low pressure system over the region

Observation of two-photon absorption in rhodamine 6G using photoacoustic technique

Two-photon absorption in Rhodamine 6G using the second harmonic of a pulsed Q-switched Nd:YAG laser has been studied by photoacoustic technique. It is observed that there is a competition between one-photon and two-photon absorption processes. At lower concentration the two-photon process is predominant over the one-photon process.Cochin University of Science and Technolog

Photoacoustic observation of excited singlet state absorption in the laser dye rhodamine 6G

S1 to S3 excited singlet state absorption and two-photon absorption in Rhodamine 6G at the pump wavelengths of 532 and 1064 nm respectively are investigated. The advantages of employing the pulsed photoacoustic technique for conveniently observing excited singlet state absorption are discussed. It is shown that, since photoacoustics and fluorescence are complementary phenomena, analysis using both techniques will yield a better understanding of optical processes in molecules like Rhodamine 6G.Cochin University of Science & Technolog

Inheritance of aroma biosynthesis pathways in citrus tetraploid somatic hybrids

Citrus somatic hybridization by protoplast fusion generates allotetraploids having chromosomes from both parents and mitochondrial and chloroplastic DNAs from either of their parents. Seedless triploids can subsequently be obtained by hybridization of tetraploid hybrids with diploids; however, these new hybrids must have good aromatic quality for the fresh fruit market. Therefore, a knowledge of inheritance mechanisms of aroma biosynthesis pathways in somatic hybrids is desirable. Aroma compounds were analyzed in leaves and peel of lime (cv. Mexican lime), grapefruit (cv. Ruby red) and their somatic hybrids grown at the Station de Recherches Agronomiques INRA-CIRAD (San Giuliano, Corsica, France). Lime-originating monoterpene aldehydes (neral, geranial) and grapefruit beta-sinensal were quantitatively recovered in the hybrid leaves while citronellal was massively overproduced in the hybrid leaves and peel with regards to its parents. Nootkatone, a grapefruit-specific sesquiterpene ketone, was fully recovered in the hybrid peel, while alpha-sinensal absent in peels from both parents was found in the hybrid. Other somatic hybrids sharing mandarin (cv. willow leaf) as their common parent, [lemon (cv. Eurékâ)+mandarin], [lime (cv. Mexican lime) + mandarin], and [kumquat (cv. Marumi) + mandarin], exihibit common features in their leaf aroma distributions: a loss of the non-mandarin parent ability to synthezise aldehydes (neral, geranial) as the aldehyde-free mandarin parent, a strong decrease in sesquiterpenes, and a halved production of methyl *methyl anthranilate with regards to the mandarin parent. Amongst key enzymes in aroma biosynthesis path-ways, activities of monoterpene synthases and acid phosphatases were measured in leaves with allylic pyrophosphates as substrates and monoterpene alcohol: NADP+oxydoreductases with monoterpene alcohols. Preliminary results indicate that activities were not enhanced, but lowered in hybrids with regards to their respective parents. (Texte intégral