Treatment Of Organotypic Cultures Research Articles

KCC2 Manipulation Alters Features of Migrating Interneurons in Ferret Neocortex.

KCC2 is a brain specific chloride-potassium cotransporter affecting neuronal development including migration and cellular maturation. It modulates chloride homeostasis influencing the switch of GABA from depolarizing to hyperpolarizing, which contributes to the cues that influence the termination of neuronal migration. The expression of KCC2 during migration of interneurons, therefore, correlates with the ability of these cells to respond to GABA as a stop signal. Manipulation of KCC2 in development can affect various aspects of migrating neurons, including the speed. We describe the effect of KCC2 downregulation and inhibition on features of migrating interneurons of normal ferret kits and those treated with methylazoxymethanol acetate, which increases KCC2. Treatment of organotypic cultures with Bisphenol A, an environmental toxin that alters gene expression, also downregulates KCC2 protein. In organotypic slices treated with the KCC2 antagonist VU0240551, chloride imaging shows inhibition of KCC2 via blockade of chloride flux. Time-lapse video imaging of organotypic cultures treated with either drug, shows a significant increase in the average speed, step size, and number of turns made by migrating neurons leaving the ganglionic eminence. Our findings demonstrate the harmful effect of environmental toxins on brain development and potential consequences in the pathogenesis of neurodevelopmental disorders.

Abstract B72: Developing drug combinations to co-target pancreatic cancer and its supporting stroma

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is characterized by an intense desmoplastic stroma, due to the activation of pancreatic stellate cells (PSC). The activated PSC are characterized by a reduction of fat droplets, expression of α-smooth muscle actin (α-SMA), and an increased synthesis and secretion of several connective tissue components such as fibronectin (FN) and collagen type I. Aberrant stromal-epithelial interactions contribute to pancreatic cancer spread and metastasis raising the possibility that targeting the stroma may represent viable strategy for treating pancreatic cancer. Our group has shown that pancreatic cancer progression can be restrained via modulation of the stellate cells in the stroma. Methods: Organotypic cultures (OT) were constructed to mimic human PDAC. Treatment of OT was performed to mimic human chemotherapy regimen cycles with all-trans retinoic acid (ATRA), targeting PSC, and the chemotherapeutic agent Gemcitabine (GEM), targeting pancreatic cancer cells (PCC). Furthermore, KPC mice (LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre) were treated with the combination of GEM and ATRA. Appropriate controls were used for both in vivo and in vitro assays using either drug alone or vehicle alone to dissect effect of individual drug. Both in vivo and in vitro assays were studied for various surrogate endpoints for chemotherapy efficacy. Results:In the organotypic model, ATRA alone or in combination with GEM reduced cancer cell and stellate cell invasion. The same treatment also reduced cancer cell proliferation. Stellate cell activation, as measured by fibronectin production per stellate cell, was significantly reduced upon combination treatment with GEM/ATRA, in comparison to cultures treated with GEM or ATRA only. In the KPC mice model, ATRA alone or in combination with GEM caused stromal collapse. The same regimen treatment led to an increase in vascular density in the tumor area and a significant impairment of the tumor growth, when compared with mice treated with ATRA or GEM alone. The number of necrotic areas was also higher in tumors from mice treated with the combination treatment of GEM/ATRA. Further assessments are being carried out. Conclusions:The combination treatment of all-trans retinoic acid and Gemcitabine may have a synergistic detrimental effect upon pancreatic cancer progression. Citation Format: Elisabete Florencio Carapuça, Emilios Gemenetzidis, Christine Feig, David Tuveson, Hemant Kocher. Developing drug combinations to co-target pancreatic cancer and its supporting stroma. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr B72.

Su1907 Developing Drug Combinations to Co-Target Pancreatic Cancer and Its Supporting Stroma

Background: Pancreatic ductal adenocarcinoma (PDAC) is characterized by an intense desmoplastic stroma, due to the activation of pancreatic stellate cells (PSC). The activated PSC are characterized by a reduction of fat droplets, expression of α-smooth muscle actin (α-SMA), and an increased synthesis and secretion of several connective tissue components such as fibronectin (FN) and collagen type I. Aberrant stromal-epithelial interactions contribute to pancreatic cancer spread and metastasis raising the possibility that targeting the stroma may represent viable strategy for treating pancreatic cancer. Our group has shown that pancreatic cancer progression can be restrained via modulation of the stellate cells in the stroma. Methods: Organotypic cultures (OT) were constructed to mimic human PDAC. Treatment of OT was performed to mimic human chemotherapy regimen cycles with all-trans retinoic acid (ATRA), targeting PSC, and the chemotherapeutic agent Gemcitabine (GEM), targeting pancreatic cancer cells (PCC). Furthermore, KPC mice (LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre) were treated with the combination of GEM and ATRA. Appropriate controls were used for both in vivo and in vitro assays using either drug alone or vehicle alone to dissect effect of individual drug. Both in vivo and in vitro assays were studied for various surrogate endpoints for chemotherapy efficacy. Results:In the organotypic model, ATRA alone or in combination with GEM reduced cancer cell and stellate cell invasion. The same treatment also reduced cancer cell proliferation. Stellate cell activation, as measured by fibronectin production per stellate cell, was significantly reduced upon combination treatment with GEM/ATRA, in comparison to cultures treated with GEM or ATRA only. In the KPC mice model, ATRA alone or in combination with GEM caused stromal collapse. The same regimen treatment led to an increase in vascular density in the tumor area and a significant impairment of the tumor growth, when compared with mice treated with ATRA or GEM alone. The number of necrotic areas was also higher in tumors from mice treated with the combination treatment of GEM/ATRA. Further assessments are being carried out. Conclusions:The combination treatment of all-trans retinoic acid and Gemcitabine may have a synergistic detrimental effect upon pancreatic cancer progression.

Tissue-Spanning Redox Gradient-Dependent Assembly of Native Human Papillomavirus Type 16 Virions

Papillomavirus capsids are composed of 72 pentamers reinforced through inter- and intrapentameric disulfide bonds. Recent research suggests that virus-like particles and pseudovirions (PsV) can undergo a redox-dependent conformational change involving disulfide interactions. We present here evidence that native virions exploit a tissue-spanning redox gradient that facilitates assembly events in the context of the complete papillomavirus life cycle. DNA encapsidation and infectivity titers are redox dependent in that they can be temporally modulated via treatment of organotypic cultures with oxidized glutathione. These data provide evidence that papillomavirus assembly and maturation is redox-dependent, utilizing multiple steps within both suprabasal and cornified layers.