Cancer Cell Study Carried Out At The University Of Bradford

cancer-cell-study-uni-bradford

A paper entitled “Plysialic acid sustains cancer cell survival and migratory capacity in a hypoxic environment” has been published by researchers at The University of Bradford and The University of Huddersfield. The study looks at Polysialic acid (a unique carbohydrate polymer expressed on the surface of neuronal cell adhesion molecules) and its association with tumour cell and adhesion in hypoxia. Their findings provide the first evidence that polySia expression sustains migratory capacity and is associated with tumour cell survival in hypoxia.

 

A key part of the study involved the use of a Whitley H35 Hypoxystation. The importance of using a piece of equipment such as a Whitley Hypoxystation is down to hypoxia having a profound effect on cancer cell growth as it occurs in poorly vascularised areas of tumours. Klaus Pors, Senior Lecturer In Chemical Biology, provided the below quote.

 

Dr Robert Falconer and colleagues are studying polysialyl transferases (polySTs), responsible for the biosynthesis of polysialic acid (polySia), as a potential antimetastatic therapeutic strategy. PolySia is a unique carbohydrate polymer capable of modulating cell-cell and cell-matrix adhesion, migration, invasion and metastasis in a number of cancers. In this study we have employed Don Whitley H35 Hypoxystation to analyse how polySia sustains cancer cell survival and migratory capacity in a hypoxic environment. We believe these results contribute significantly to our understanding of how polySia supports an aggressive phenotype and further studies are underway to underpin these findings in a therapeutic context.

 

Furthermore, the paper also states that the “results have significant potential implications for polyST inhibition as an anti-metastatic therapeutic strategy and for targeting hypoxic cancer cells”.

 

The group are set to continue this line of work, using the Whitley H35 Hypoxystation, keep an eye on the Meintrup DWS blog for more articles on this.

Physiological Oxygen is Healthier for Cell Cultures

Physiological Oxygen is Healthier for Cell Cultures

Drs. Timpano and Uniacke, Hypoxystation users at University of Guelph in Ontario, have published a very thorough study examining the molecular basis of cells’ reactions to differing levels of hypoxia. In their paper “Human Cells Cultured Under Physiological Oxygen Utilize Two Cap-binding Proteins to Recruit Distinct mRNAs for Translation” (Journal of Biological Chemistry 291:20; 2016), they examine 2 different translation initiation proteins, eiF4E and eiF4E2, that are activated under either high (>8% O2) or low (<1% O2) oxygen levels, with the aid of mTORC1 or HIF-2α, respectively, and activated simultaneously in an area of low- to mid-level physioxia (1-8% O2). Timpano and Uniacke were able to stably and accurately create low oxygen in their Hypoxystation by Hypoxygen, which provides a closed workstation environment that enables researchers to culture and manipulate cells inside the chamber through gloveless sleeves, eliminating the negative consequences of spikes of higher oxygen and lower temperatures encountered in an incubator as cell cultures are growing. Their research into translational modulation of the proteome using the Hypoxystation gives seminal insights into physioxia as the natural condition for cells, both in vitro and in vivo.

“Culturing cells in ambient air could be far from physiological with respect to oxygen. Oxygen is a surprisingly neglected factor (in cell culture)” – Dr Timpano and Dr Uniacke, University of Guelph, Ontario, Canada

Through polysome association experiments with cells growing at ambient air versus lower oxygen levels of 1%, 3%, 5%, and 8%, RNA analysis, and m7-GTP cap-binding assays, Timpano and Uniacke were able to demonstrate that the oxygen concentration in the workstation was sufficient to either repress or increase the activity of eiF4E and eiF4E2, reflecting mechanisms that occur during development but also during tumor progression and in ischemic diseases. Cells can reversibly cycle between utilisation of the eiF4E protein, which preferentially binds to the 5′ TOP mRNA’s at >8% O2 and is impaired at hypoxia, and eiF4E2, which is active at <1% O2 and utilizes binding motifs in the 3′ UTR of the mRNA. The eIF4E type of mRNA’s code for housekeeping proteins while the eIF4E2-dependant mRNA’s encode signaling proteins needed to respond to environmental signals, allowing cells to control translation dynamically and giving cancer cells an edge during tumor progression, as hypoxia increases.

 

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Whitley H35 Hypoxystation used in tumour study

KONICA MINOLTA DIGITAL CAMERA

Researchers from Oxford and Stanford universities have been using an Whitley H35 Hypoxystation to look at how the hypoxic conditions of tumours repress DNA repair pathways that protect against genomic instability. Hypoxystation users Leszczynska et al describe the interaction of DNA damage kinase ATM with the ATM interactor ATMIN within hypoxia as well as the downstream consequences for DNA repair. An abstract from the article is posted below, as well as a link to the full article.

 

ATM activation is induced at severe hypoxia as a result of replication stress, and was thought to be dependent on the ATM interactor ATMIN, especially in the absence of DNA damage. Using ATMIN siRNA, ATM inhibitors, and knock-out cell lines, the authors were able to establish that ATMIN is not required for the activation of ATM in response to hypoxia-induced replication stress, and that ATMIN is repressed at hypoxia, an effect mediated by both p53 and HIF-1. The cells were exposed to varying degrees of hypoxia, from mild (2%) down to extreme (0.1%) in an Whitley H35 Hypoxystation by Don Whitley Scientific. The closed cell culture environment created in the Hypoxystation mimics physiological conditions with regard to oxygen, CO2, temperature, and humidity and enables cancer researchers to obtain a clearer picture of in vivo processes. qPCR analysis of cells in response to hypoxia and exposure to inhibitors of proteasomal degradation indicate that the repressive effect of hypoxia is due to inhibition of translation as opposed to transcription or altered stability of ATMIN.

 

Using ATMIN siRNA at various levels of hypoxia, the authors found that loss of ATMIN impairs base excision repair BER and increases sensitivity to DMA damaging agents such as methyl methanesulfonate MMS. Decreased ATMIN levels also decrease the expression of dynein light chain LC8-type 1 DYNLL1, again in a p53-dependent manner. Thus, the authors have found a new link between tumor hypoxia and ATMIN-regulated DYNLL1 expression. Loss of DYNLL1 in hypoxic tumors affects ciliogenesis, mitosis, cellular localization of proteins, to name a few, and justifies further research into the roles of ATMIN and DYNLL1 in cancer.

 

The full paper can be read here – Mechanisms and consequences of ATMIN repression in hypoxic conditions: roles for p53 and HIF-1