PVT1, a YAP1 dependent stress responsive lncRNA drives ovarian cancer metastasis and chemoresistance

Metastatic growth of ovarian cancer cells into the peritoneal cavity requires adaptation to various cellular stress factors to facilitate cell survival and growth. Here we demonstrate the role of PVT1, one such stress induced long non-coding RNA, in ovarian cancer growth and metastasis. PVT1 is an amplified and overexpressed lncRNA in ovarian cancer with strong predictive value for survival and response to targeted therapeutics. We find that expression of PVT1 is regulated by ovarian tumor cells in response to cellular stress, particularly loss of cell-cell contacts and changes in matrix rigidity occurring in a YAP1 dependent manner. Induction of PVT1 promotes tumor cell survival, growth, and migration. Conversely, reducing PVT1 levels robustly abrogates metastatic behavior and tumor cell dissemination in cell lines and syngeneic transplantation models in vivo. We find that reducing PVT1 causes widespread transcriptome changes leading to alterations in cellular stress response and metabolic pathways including doxorubicin metabolism, which directly impacts chemosensitivity. Together, these findings implicate PVT1 as a promising therapeutic target to suppress metastasis and avoid chemoresistance in ovarian cancer.

Epac1 regulates cellular SUMOylation by promoting the formation of SUMO-activating nuclear condensates

Protein SUMOylation plays an essential role in maintaining cellular homeostasis when cells are under stress. However, precisely how SUMOylation is regulated, and a molecular mechanism linking cellular stress to SUMOylation remains elusive. Herein, we report that cAMP, a major stress-response second messenger, acts through Epac1 as a regulator of cellular SUMOylation. The Epac1-associated proteome is highly enriched with components of the SUMOylation pathway. Activation of Epac1 by intracellular cAMP triggers phase separation and the formation of nuclear condensates containing Epac1 and general components of the SUMOylation machinery to promote cellular SUMOylation. Furthermore, genetic knockout of Epac1 obliterates oxidized low-density lipoprotein induced cellular SUMOylation in macrophages, leading to suppression of foam cell formation. These results provide a direct nexus connecting two major cellular stress responses to define a molecular mechanism in which cAMP regulates the dynamics of cellular condensates to modulate protein SUMOylation.

Combating the amyloid-induced cellular toxicity and stiffness by designer peptidomimetics

Amyloid beta (Aβ) aggregation species-associated cellular stress instigates cytotoxicity and adverse cellular stiffness to neuronal cells. The study and modulation of these adverse effects demand immediate attention to tackle Alzheimer’s...

Loss of FVIII Expression by Possible Interlinked Immune and Cellular Stress Response in Hemophilia A Mice Treated with AAV Gene Therapy

Background Hemophilia A is an X-linked genetic disorder caused by a mutation in the gene for factor VIII (FVIII) protein that reduces the ability of blood to clot. Clinical drug trials have shown the potential of adeno-associated virus (AAV) gene therapy as a one-time treatment for hemophilia A that can produce sustained high levels of FVIII. However, a gradual decline in protein levels has been observed in patients after 2-4 years. The hypothesis being tested in the Herzog Lab is that an interlinked immune and cellular stress response could be causing the loss of expression. Methods Two groups of Hemophilia A mice were administered AAV therapy, with one group receiving recurrent doses of Rapamycin. Blood samples were taken at weeks 4, 8, 12 and 14. Mice were euthanized at weeks 4, 8, and 14, and their livers were harvested. qPCR was used to measure AAV copy numbers and FVIII mRNA at 4, 8, and 14 weeks. Cryosections of mice livers from weeks 4, 8, and 14 were stained with antibodies for FVIII protein and CD8. Results qPCR showed roughly half as much AAV copy numbers in the rapamycin group at all time points, and little difference in FVIII mRNA between the groups. There was also a large decrease in AAV copy numbers and FVIII mRNA in both groups between 8 and 14 weeks. Immunohistochemistry showed less CD8 and more FVIII signal in mice treated with rapamycin. Discussion Experiments are currently being performed to investigate the decline in AAV copy numbers and mRNA between weeks 8 and 14. The immunohistochemistry data shows a relationship between increased FVIII protein levels and decreased cellular immune response but does not explain the gradual decline in FVIII. Further investigation into FVIII expression following AAV gene therapy could lead to an effective one-time treatment for hemophilia A.

Environmental Particulate Air Pollution Exposure and the Oxidative Stress Responses: A Brief Review of the Impact on the Organism and Animal Models of Research

Particulate matter (PM) is a mixture of solid particles and liquid droplets found in the air, and it is one of the most harmful air pollutants. When inhaled, it affects the pulmonary system, cardiovascular systems, and other tissues. The size, composition, and deposition of PM, mainly related to fine and ultrafine particulate matter, are factors that determine the harmful effects of exposure to particles. Among the main effects is the inducer of ROS production, and consequently oxidative tissue damage in target organs and other responses, mediated by inflammatory cytokines and cellular stress response. The main pathway through which particles are potent mediators of oxidative stress is the damage caused to DNA and lipid molecules, whereas the pro-inflammatory response involves an immune response against PM, which in turn, it is related to cell stress responses observed by heat shock proteins (HSPs) expression and release. Thus, the ability of an organism to respond to PM inhalation requires anti-oxidative, anti-inflammatory, and cellular stress defenses that can be impaired in susceptible subjects as people with chronic diseases as diabetes and obesity. In this chapter, we discuss the mechanistic aspects of PM effects on health and present some animal research models in particle inhalation studies.

The blended phenotype of a germline RIT1 and a mosaic PIK3CA variant

We report a patient with a germline RIT1 and a mosaic PIK3CA variant. The diagnosis of the RASopathy was confirmed by targeted sequencing following the identification of transient cardiomyopathy in a patient with PIK3CA-related overgrowth spectrum (PROS). Our observation confirms that the PIK3CA gain-of-function (GoF) variant effects dominate those of the RASopathy, and the resulting blended phenotype mostly resembles megalencephaly-capillary malformation syndrome (MCAP PROS). There appears to be interaction between RIT1 and PI3K-AKT because the latter pathway is needed for the growth-promoting activity of the first, at least in adenocarcinomas, but the details of this interaction are not known. If so, the PIK3CA somatic variant may not be just a chance event. It could also be of etiological relevance that Rit activation mediates resistance to cellular stress—that is, promotes cell survival. This anti-apoptotic effect could also make it more likely that a cell that spontaneously acquires a PIK3CA GoF variant will survive and proliferate. We aim to encourage clinicians to investigate atypical findings in individuals with PROS. If further similar cases are reported, this would suggest that the establishment of PROS mosaicism is facilitated by the background of a RASopathy.

The Interplay Between Stress Related Genes and Its Role in Human Longevity: Insights for Translational Studies

Human lifespan is a multifactorial trait resulted from complicated interplay among many genetic and environmental factors. Despite substantial progress in clarifying many aspects of lifespan’ variability the mechanism of its multifactorial regulation remains unclear. In this paper we investigate the role of genes from integrated stress response (ISR) pathway in such regulation. Experimental studies showed that persistent cellular stress may result in cellular senescence (for proliferating cells), or in apoptosis (for post-mitotic cells) which may affect health and lifespan in laboratory animals. These studies also showed which ISR genes are likely to interplay to produce joint effects on these traits. Note that in humans, the interplay between these genes does not necessarily influence these traits. This is because biological mechanisms regulating these traits in laboratory animals and humans may differ. This means that, when possible, the experimentally detected connections promising for human applications, should be verified using available human data before their testing in expensive clinical trials. In this paper we used HRS data to test connection between SNPs from the EIF2AK4 gene that senses cellular stress signals and the DDIT3 gene from the apoptosis regulation part of the ISR. We found genome wide significant associations between interacting SNPs from these genes and longevity. This result shows that available human data may be successfully used for making important steps in translation of experimental research findings towards their application in humans. Following this strategy may increase efficiency of clinical trials aiming to find appropriate medications to promote human health and longevity.

Effect of Combined Stressors on C. elegans Lifespan

Cellular stress is a fundamental component of age-associated disease. Cells experience many forms of stress (oxidative, heavy metal, etc.), and as we age the burden of stress and resulting damage increases while our cells’ ability to deal with the consequences becomes diminished due to dysregulation of cellular stress response pathways. By understanding how cells respond to stress we aim to slow age-associated deterioration and develop treatment targets for age-associated disease. The majority of past work has focused on understanding responses to individual stressors. In contrast, how pathology and stress responses differ in the presence of multiple stressors is relatively unknown; we investigate that here. We cultured worms on agar plates with different combinations of arsenic, copper, and DTT (which create oxidative/proteotoxic, heavy metal, and endoplasmic reticulum (ER) stress, respectively) at doses that result in 20% lifespan reduction individually and measured the effect on lifespan. We found that arsenic/copper and arsenic/DTT combinations created additive lifespan reductions while the copper/DTT combination created an antagonistic lifespan reduction when compared to controls (p<0.05). This antagonistic toxicity suggests an interaction either between the mechanisms of toxicity or the cellular response to copper and DTT. We are now evaluating the impact of copper and DTT individually and in combination on unfolded protein and heavy metal response pathways to understand the underlying mechanism of the interaction. Additionally, we are continuing to screen stressors to identify combinations that cause non-additive (synergistic or antagonistic) toxicity to build a comprehensive model of the genetic stress response network in C. elegans.