Effect of Short-Chain Fatty Acid Acetate on Colon Cancer

Acetate is a short chain fatty acid produced as a result of fermentation of ingested fibers by the gut microbiota. While it has been shown to reduce cell proliferation in some cancer cell lines1,2, more recent studies on liver3 and brain4 tumours suggest that acetate may actually promote tumour growth. Acetate in the cell is normally converted into acetyl-coA by two enzymes and metabolized; mitochondrial (ACSS1) and cytosolic (ACSS2) acetyl-coA synthetase. In the mitochondria acetyl-coA is utilized in the TCA cycle. In the cytosol it is utilized in lipid synthesis. In this study, the effect of acetate treatment on the growth of HT29 colon cancer cell line and its mechanism of action was assessed. HT29 human colorectal adenocarcinoma cells were treated with 10mM NaAc and cell viability, cellular bioenergetics and gene expression were investigated. Cell viability was assessed 24 hours after treatment using an MTT assay (Sigma, UK, n=8). Cellular oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) was measured by XFe Analyzer (Seahorse Bioscience, USA). After a baseline reading cells were treated and OCR and ECAR measurements were observed for 18 hours (n=4). Total mRNA was isolated 24 hours after treatment using RNeasy kit (Qiagen, USA). Quantitative PCR reactions were performed using Taqman gene expression assays and Taqman Universal PCR Master Mix (ThermoFisher Scientific, UK) on Applied Biosystems 7500 Fast Real-Time PCR System (Life Technologies, USA) and analysed using ΔΔCt method (n=3). Acetate treatment led to a significant reduction in cell viability (15.9%, Figure 1). OCR, an indicator of oxidative phosphorylation, was significantly increased (p<0.0001) while ECAR, an indicator of glycolysis, was significantly reduced (p<0.0001, Figure 2). Gene expression of ACSS1 was increased by 1.7 fold of control (p=0.07) and ACSS2 expression was reduced to 0.6 fold of control (p=0.06, Figure 3). In conclusion, in colon cancer cells acetate supplementation induces cell death and increases oxidative capacity. These changes together with the trending decrease in ACSS2 expression suggest suppression of lipid synthesis pathways. We hypothesize that the reduced tumor growth by acetate is a consequence of the suppression of ACSS2 and lipid synthesis, both effects reported previously to reduce tumor growth3–5. These effects clearly warrant further investigation.

Next generation e-learning platform: virtual laboratory simulations

Bioscience subjects require a significant amount of training in laboratory techniques to produce highly skilled science graduates. Many techniques which are currently used in diagnostic, research and industrial laboratories require expensive equipment for single users; examples of which include next generation sequencing, quantitative PCR, mass spectrometry and other analytical techniques. The cost of the machines, reagents and limited access frequently preclude undergraduate students from using such cutting edge techniques. In addition to cost and availability, the time taken for analytical runs on equipment such as High Performance Liquid Chromatography (HPLC) does not necessarily fit with the limitations of timetabling. Understanding the theory underlying these techniques without the accompanying practical classes can be unexciting for students. One alternative from wet laboratory provision is to use virtual simulations of such practical which enable students to see the machines and interact with them to generate data. The Faculty of Science and Technology at the University of Westminster has provided all second and third year undergraduate students with iPads so that these students all have access to a mobile device to assist with learning. We have purchased licences from Labster to access a range of virtual laboratory simulations. These virtual laboratories are fully equipped and require student responses to multiple answer questions in order to progress through the experiment. In a pilot study to look at the feasibility of the Labster virtual laboratory simulations with the iPad devices; second year Biological Science students (n=36) worked through the Labster HPLC simulation on iPads. The virtual HPLC simulation enabled students to optimise the conditions for the separation of drugs. Answers to Multiple choice questions were necessary to progress through the simulation, these focussed on the underlying principles of the HPLC technique. Following the virtual laboratory simulation students went to a real HPLC in the analytical suite in order to separate of asprin, caffeine and paracetamol. In a survey 100% of students (n=36) in this cohort agreed that the Labster virtual simulation had helped them to understand HPLC. In free text responses one student commented that "The terminology is very clear and I enjoyed using Labster very much”. One member of staff commented that “there was a very good knowledge interaction with the virtual practical”.