Phencyclidine (PCP) administration elicits positive and negative symptoms that resemble those of schizophrenia and is widely accepted as a model for the study of this human disorder. Group II metabotropic glutamate receptor (mGluR) agonists have been reported to reduce the behavioral and neurochemical effects of PCP. The peptide neurotransmitter, N-acetylaspartylglutamate (NAAG), is a selective group II agonist. We synthesized and characterized a urea-based NAAG analogue, ZJ43. This novel compound is a potent inhibitor of enzymes, glutamate carboxypeptidase II (K i ¼ 0.8 nM) and III (K i ¼ 23 nM) that deactivate NAAG following synaptic release. ZJ43 (100 lM) does not directly interact with NMDA receptors or metabotropic glutamate receptors. Administration of ZJ43 significantly reduced PCPinduced motor activation, falling while walking, stereotypic circling behavior, and head movements. To test the hypothesis that this effect of ZJ43 was mediated by increasing the activation of mGluR3 via increased levels of extracellular NAAG, the group II mGluR selective antagonist LY341495 was co-administered with ZJ43 prior to PCP treatment. This antagonist completely reversed the effects of ZJ43. Additionally, LY341495 alone increased PCP-induced motor activity and head movements suggesting that normal levels of NAAG act to moderate the effect of PCP on motor activation via a group II mGluR. These data support the view that NAAG peptidase inhibitors may represent a new therapeutic approach to some of the components of schizophrenia that are modeled by PCP.

No abstract

Despite adequately expressing tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptors DR4/DR5, malignant cells are frequently refractory to the cytotoxic effect of this apoptosis-inducing ligand. The susceptibility of cancer cells to TRAIL can be potentiated by cisplatin (CDDP). This study was designed to evaluate the ability of cisplatin to enhance the cytotoxic effect of TRAIL gene therapy using the recombinant adenovirus-mediated tumor-selective expression of membrane-bound green fluorescence protein (GFP)-TRAIL fusion protein (AdVgTRAIL) on thoracic cancer cells and to elucidate the putative mechanisms responsible for this synergistic combination effect. While causing little death of cultured thoracic cancer cells by itself, AdVgTRAIL in combination with CDDP, on the other hand, mediated profound supra-additive cytotoxicity and apoptosis via a strong bystander effect. CDDP/AdVgTRAIL-induced cytotoxicity was completely abrogated either by the pancaspase inhibitor zVAD-fmk or by the selective caspase 9 inhibitor or by transient knockdown of caspase 9 by siRNA, indicating that this process was caspase-mediated and mitochondria-dependent. This was confirmed by the observation that Bcl2 overexpression protected the cells from combinationinduced cytotoxicity. Robust activation of caspase 8 activity in combination-treated cells was blocked by overexpression of Bcl2, indicating that caspase 8 activation was secondary to the mitochondria-mediated amplification feedback loop. Combining CDDP with AdVgTRAIL greatly enhances its tumoricidal efficacy in cultured thoracic cancer cells in vitro. The two agents interact to mediate profound activation of caspase cascade via recruitment of the mitochondria and positive feedback loop. The CDDP/ AdVgTRAIL combination also exhibits a strong antitumor effect in in vivo animal model of human cancer xenografts.

Apo2L/TRAIL is actively investigated as a novel targeted agent to directly induce apoptosis of susceptible cancer cells. Apo2L/TRAIL-refractory cells can be sensitized to the cytotoxic effect of this ligand by cytotoxic chemotherapeutics. The aim of this study was to evaluate the in vitro tumoricidal activity of the Apo2L/TRAIL + Trichostatin A in cultured thoracic cancer cells and to elucidate the molecular basis of the synergistic cytotoxicity of this combination. Concurrent exposure of cultured cancer cells to sublethal concentrations of Apo2L/TRAIL and Trichostatin A resulted in profound enhancement of Apo2L/TRAIL-mediated cytotoxicity in all cell lines regardless of their intrinsic susceptibility to this ligand. This combination was not toxic to primary normal cells. While Apo2L/TRAIL alone or Trichostatin A alone mediated < 20% cell death, 60 to 90% of cancer cells were apoptotic following treatment with TSA + Apo2L/TRAIL combinations. Complete translocation of Bax from the cytosol to the mitochondria compartment was mainly observed in combination-treated cells and this was correlated with robust elevation of caspase 9 proteolytic activity indicative of activation of the mitochondria apoptogenic effect. Profound TSA + Apo2L/TRAIL-mediated cytotoxicity and apoptosis were completely abrogated by either Bcl2 over-expression or by the selective caspase 9 inhibitor, highlighting the essential role of mitochondria-dependent apoptosis signaling cascade in this process. Moreover, increased caspase 8 activity observed in cells treated with the TSA + Apo2L/TRAIL combination was completely suppressed by Bcl-2 over-expression or by the selective caspase 9 inhibitor indicating that the elevated caspase 8 activity in combination-treated cells was secondary to a mitochondria-mediated amplification feedback loop of caspase activation. These finding form the basis for further development of HDAC inhibitors + Apo2L/TRAIL combination as novel targeted therapy for thoracic malignancies.

In response to the COVID-19 pandemic reducing medical student presence on clinical services and in classrooms, academic institutions are utilizing a virtual format to continue medical student education. We describe a successful initial experience implementing a virtual elective in interventional radiology (IR) and provide the course framework, student feedback, and potential improvements. Materials and methods: A 2-week virtual IR elective curriculum was created utilizing a combination of synchronous and asynchronous learning and the "flipped" classroom educational model. Students virtually participated in daily IR resident education conferences, resident-led case review sessions, and dedicated lectures. Asynchronous prelearning material consisted of text and video correlating to lecture topics. Anonymous precourse and postcourse surveys were sent to all participating students (n = 10). Results: Ten students (100%) completed precourse and seven (70%) completed postcourse surveys. Enrolled students were considering residencies in surgery (50%), internal medicine (40%), interventional radiology (30%), and/or diagnostic radiology (30%). Students' understanding of what IRs do and the procedures they perform (p < 0.001), when to consult IR for assistance in patient management (p = 0.005), and the number of IR procedures students could recall (p = 0.015) improved after the course. Case-review sessions and virtual lectures ranked as having the highest education value. Students recommended additional small-group case workshops. Conclusion: This successful virtual IR elective provides a framework for others to continue IR medical student education during the pandemic and grow the specialty's presence within an increasingly virtual medical school curriculum. The described model may be modified to improve IR education beyond the COVID-19 era.

Metastatic liver disease is a major cause of cancer-related morbidity and mortality. Surgical resection is considered the only curative treatment, yet only a minority is eligible. Patients who present with unresectable disease are treated with systemic agents and/or locoregional therapies. The latter include thermal ablation and catheter-based transarterial interventions. Thermal ablation is reserved for those with limited tumor burden. It is used to downstage the disease to enable curative surgical resection, as an adjunct to surgery, or in select patients it is potentially curative. Transarterial therapies are indicated in those with more diffuse disease. The goals of care are to palliate symptoms and prolong survival. The indications and supporting data for thermal ablation and transarterial interventions are reviewed, technical and tumor factors that need to be considered prior to intervention are outlined, and finally several cases are presented.

No abstract

Histone deacetylase inhibitors (HDACIs) are novel anticancer agents with potent cytotoxicity against a wide range of malignancies. We have previously demonstrated that either Calphostin C (CC) (a protein kinase C (PKC) inhibitor) or Parthenolide (an NF-kB inhibitor) abrogates HDACI-induced transcriptional activation of NF-kB and p21, which is associated with profound potentiation of HDACI-mediated induction of apoptosis. Valproic acid (VA), a commonly used antiepileptic agent, has recently been shown to be an HDACI. This study was aimed to evaluate the anticancer property of VA in thoracic cancer cells and the development of clinically relevant strategies to enhance VA-mediated induction of apoptosis using kinase inhibitors Staurosporine (STP) or its analogue UCN-01. Treating cultured thoracic cancer cells with VA (0.62 -10.0 mM) resulted in significant cell line-and dose-dependent growth inhibition (IC 50 values: 4.1 -6.0 mM) and cell cycle arrest at G1/S checkpoint with profound accumulation of cells at G0/G1 phase but little induction of apoptosis. Valproic acid, being an HDACI, caused significant dose-dependent accumulation of hyperacetylated histones, following 24 h of treatment. Valproic acid-mediated 5 -20-fold upregulation of transcriptional activity of NF-kB was substantially (50 -90%) suppressed by cotreatment with CC, STP or UCN-01. Whereas minimal death (o20%) was observed in cells treated with either VA (1.0 or 5.0 mM) alone or kinase inhibitors alone, 60 -90% of cells underwent apoptosis following exposure to combinations of VA þ kinase inhibitors. Kinase inhibitor-mediated suppression of NF-kB transcriptional activity played an important role in sensitising cancer cells to VA as direct inhibition of NF-kB by Parthenolide drastically synergised with VA to induce apoptosis (VA þ Parthenolide: 60 -90% compared to o20% following single-drug treatments). In conclusion, VA, a well-known antiepileptic drug, has mild growth-inhibitory activity on cultured cancer cells. The weak VA-mediated induction of apoptosis of thoracic cancer cells can be profoundly enhanced either by Parthenolide, a pharmacologic inhibitor of NF-kB, or by UCN-01 a kinase inhibitor that has already undergone phase I clinical development. Combinations of VA with either a PKC inhibitor or an NF-kB inhibitor are promising novel molecularly targeted therapeutics for thoracic cancers.