Sab concentrations indicate chemotherapeutic susceptibility in ovarian cancer cell lines.

The occurrence of chemotherapy-resistant tumors makes ovarian cancer (OC) the most lethal gynecological malignancy. While many factors may contribute to chemoresistance, the mechanisms responsible for regulating tumor vulnerability are under investigation. Our analysis of gene expression data revealed that Sab, a mitochondrial outer membrane (MOM) scaffold protein, was down-regulated in OC patients. Sab-mediated signaling induces cell death, suggesting that this apoptotic pathway is diminished in OC. We examined Sab expression in a panel of OC cell lines and found that the magnitude of Sab expression correlated to chemo-responsiveness; wherein, OC cells with low Sab levels were chemoresistant. The Sab levels were reflected by a corresponding amount of stress-induced c-Jun N-terminal kinase (JNK) on the MOM. BH3 profiling and examination of Bcl-2 and BH3-only protein concentrations revealed that cells with high Sab concentrations were primed for apoptosis, as determined by the decrease in pro-survival Bcl-2 proteins and an increase in pro-apoptotic BH3-only proteins on mitochondria. Furthermore, overexpression of Sab in chemoresistant cells enhanced apoptotic priming and restored cellular vulnerability to a combination treatment of cisplatin and paclitaxel. Contrariwise, inhibiting Sab-mediated signaling or silencing Sab expression in a chemosensitive cell line resulted in decreased apoptotic priming and increased resistance. The effects of silencing on Sab on the resistance to chemotherapeutic agents were emulated by the silencing or inhibition of JNK, which could be attributed to changes in Bcl-2 protein concentrations induced by sub-chronic JNK inhibition. We propose that Sab may be a prognostic biomarker to discern personalized treatments for OC patients.

Sub-chronic administration of LY294002 sensitizes cervical cancer cells to chemotherapy by enhancing mitochondrial JNK signaling.

Chemo-sensitization is used to improve the efficacy of chemotherapeutic agents against cancers, and understanding the precise molecular mechanisms of chemo-sensitization could lead to safer and more effective approaches to treat cancer. We have previously demonstrated that mitochondrial c-Jun N-terminal Kinase (JNK) signaling is a critical component of cell death. Mitochondrial JNK signaling is coordinated on the scaffold protein Sab. In this work, we developed a sub-chronic chemo-sensitization model by exposing HeLa cells to low-dose (2 µM) LY294002. We found that this treatment increased Sab expression on mitochondria, an effect not observed in acute exposures. To examine the role of Sab in chemo-sensitization, we ectopically expressed and silenced Sab in HeLa cells. We found that elevating Sab levels in HeLa cells increased the efficacy of chemotherapeutic agents, paclitaxel and cisplatin, while silencing Sab decreased the sensitivity of cells towards these agents. The effect of Sab-mediated signaling appeared to be dependent upon mitogen dependent protein kinases (MAPKs) as ablation of Sab's MAPK-binding motifs prevented chemo-sensitization. These results suggest that mitochondrial JNK signaling is an adaptable signaling pathway that can be enhanced or restored in cancer cells to improve therapeutic efficacy.

Increasing confidence in new approach methodologies for inhalation risk assessment with multiple end point assays using 5-day repeated exposure to 1,3-dichloropropene.

New Approach Methodologies (NAMs) are being widely used to reduce, refine, and replace, animal use in studying toxicology. For respiratory toxicology, this includes both in silico and in vitro alternatives to replace traditional in vivo inhalation studies. 1,3-Dichloropropene (1,3-DCP) is a volatile organic compound that is widely used in agriculture as a pre-planting fumigant. Short-term exposure of humans to 1,3-DCP can result in mucous membrane irritation, chest pain, headache, and dizziness. In our previous work, we exposed differentiated cells representing different parts of the respiratory epithelium to 1,3-DCP vapor, measured cytotoxicity, and did In Vitro to In Vivo Extrapolation (IVIVE). We have extended our previous study with 1,3-DCP vapors by conducting transcriptomics on acutely exposed nasal cultures and have implemented a separate 5-day repeated exposure with multiple endpoints to gain further molecular insight into our model. MucilAir™ Nasal cell culture models, representing the nasal epithelium, were exposed to six sub-cytotoxic concentrations of 1,3-DCP vapor at the air-liquid interface, and the nasal cultures were analyzed by different methodologies, including histology, transcriptomics, and glutathione (GSH) -depletion assays. We observed the dose-dependent effect of 1,3-DCP in terms of differential gene expression, change in cellular morphology from pseudostratified columnar epithelium to squamous epithelium, and depletion of GSH in MucilAir™ nasal cultures. The MucilAir™ nasal cultures were also exposed to 3 concentrations of 1,3-DCP using repeated exposure 4 h per day for 5 days and the histological analyses indicated changes in cellular morphology and a decrease in ciliated bodies and an increase in apoptotic bodies, with increasing concentrations of 1,3-DCP. Altogether, our results suggest that sub-cytotoxic exposures to 1,3-DCP lead to several molecular and cellular perturbations, providing significant insight into the mode-of-action (MoA) of 1,3-DCP using an innovative NAM model.

Integrative Transcriptome Analyses of the Human Fallopian Tube: Fimbria and Ampulla-Site of Origin of Serous Carcinoma of the Ovary.

Epithelial ovarian cancer represents a group of heterogeneous diseases with high grade serous cancer (HGSC) representing the most common histotype. Molecular profiles of precancerous lesions found in the fallopian tube have implicated this tissue as the presumptive site of origin of HGSC. Precancerous lesions are primarily found in the distal fallopian tube (fimbria), near the ovary relative to the proximal tissue (ampulla), nearer to the uterus. The proximity of the fimbria to the ovary and the link between ovulation, through follicular fluid release, and ovarian cancer risk led us to examine transcriptional responses of fallopian tube epithelia (FTE) at the different anatomical sites of the human fallopian tube. Gene expression profiles of matched FTE from the fimbria and from premenopausal women resulted in differentially expressed genes (DEGs): CYYR1, SALL1, FOXP2, TAAR1, AKR1C2/C3/C4, NMBR, ME1 and GSTA2. These genes are part of the antioxidant, stem and inflammation pathways. Comparisons between the luteal phase (post-ovulation) to the follicular phase (pre-ovulation) demonstrated greater differences in DEGs than a comparison between fimbria and fallopian tube anatomical differences alone. This data suggests that cyclical transcriptional changes experienced in pre-menopause are inherent physiological triggers that expose the FTE in the fimbria to cytotoxic stressors. These cyclical exposures induce transcriptional changes reflective of genotoxic and cytotoxic damage to the FTE in the fimbria which are closely related to transcriptional and genomic alterations observed in ovarian cancer.

Overview on the Current Status of Zika Virus Pathogenesis and Animal Related Research.

There is growing evidence that Zika virus (ZIKV) infection is linked with activation of Guillan-Barré syndrome (GBS) in adults infected with the virus and microcephaly in infants following maternal infection. With the recent outpour in publications by numerous research labs, the association between microcephaly in newborns and ZIKV has become very apparent in which large numbers of viral particles were found in the central nervous tissue of an electively aborted microcephalic ZIKV-infected fetus. However, the underlying related mechanisms remain poorly understood. Thus, development of ZIKV-infected animal models are urgently required. The need to develop drugs and vaccines of high efficacy along with efficient diagnostic tools for ZIKV treatment and management raised the demand for a very selective animal model for exploring ZIKV pathogenesis and related mechanisms. In this review, we describe recent advances in animal models developed for studying ZIKV pathogenesis and evaluating potential interventions against human infection, including during pregnancy. The current research directions and the scientific challenges ahead in developing effective vaccines and therapeutics are also discussed.

Analysis of Chemotherapeutic Drug Delivery at the Single Cell Level Using 3D-MSI-TOF-SIMS.

In this work, we show the advantages of label-free, tridimensional mass spectrometry imaging using dual beam analysis (25 keV Bi3+) and depth profiling (20 keV with a distribution centered at Ar1500+) coupled to time of flight secondary ion mass spectrometry (3D-MSI-TOF-SIMS) for the study of A-172 human glioblastoma cell line treated with B-cell lymphoma 2 (Bcl-2) inhibitor ABT-737. The high spatial (~250 nm) and high mass resolution (m/Δm ~10,000) of TOF-SIMS permitted the localization and identification of the intact, unlabeled drug molecular ion (m/z 811.26 C42H44ClN6O5S2- [M - H]-) as well as characteristic fragment ions. We propose a novel approach based on the inspection of the drug secondary ion yield, which showed a good correlation with the drug concentration during cell treatment at therapeutic dosages (0-200 µM with 4 h incubation). Chemical maps using endogenous molecular markers showed that the ABT-737 is mainly localized in subsurface regions and absent in the nucleus. A semiquantitative workflow is proposed to account for the biological cell diversity based on the spatial distribution of endogenous molecular markers (e.g., nuclei and cytoplasm) and secondary ion confirmation based on the ratio of drug-specific fragments to molecular ion as a function of the therapeutic dosage. Graphical Abstract ᅟ.