research critique paper-1200 wordsAnalyses the article attached titled "Cadherin Switch during EMT in Neural Crest Cells Leads to Contact Inhibition of Locomotion via Repolarization of Forces" and...

Paper Critique
Abstract
Contact Inhibition of Locomotion (CIL) is a series of steps that the cells use to move away from one another after cell-to-cell contact. This process was first studied by Abercrombie and Heaysman more than 50 years ago in chick hear fi
oblasts. The significance of this process was observed when it was shown that any inhibition in the process can lead to invasive metastasis. It was also observed in 2010 that the CIL process has certain role to play in the prostate cancer (Astin, 2010). The process of CIL also plays an important role in the em
yonic stage in humans as it is an important process for the development of neural crest (NC) cells and macrophages (Stramer, 2010). The model system was the neural crest cells and how repolarization of forces leads to CIL.
Certain questions about CIL are still unanswered and the authors of this study tried to answer them. The authors wanted to see why some cells perform CIL while certain cells do not. The researchers also wanted to see why certain cell-to-cell interactions form stable adhesions while the stable junctions are transient during the CIL. The authors hypothesis was that the cadherin switch during the EMT in neural crest cells would lead to CIL by the repolarization of forces (Scrapa, 2015).
The major findings of the study were that the neural crest (NC) cells which are a population of em
yonic stem cells, acquire the CIL and start their epithelial-to-mesenchymal EMT program at the same time and then they start migrating. The study of pre-migratory and migratory NC cells allowed the researchers to infer that the switching E-to-N-cadherin while EMT is going on becomes essential for CIL. The E-cadherin is able to inhibit cell polarity due to contact between cells before EMT via p120 and Rac1. The final conclusion of the researchers was that the cadherin switch results in
eakdown of cell-to-cell junction by generation of powerful forces which are a result of repolarization.
Evidence Supporting Major Findings
Certain experiments were conducted by the researchers to reach their aim and prove their hypothesis.
1) The first result they obtained was that NC cells show the property of CIL as a developmental regulation and it is acquired during EMT. To prove this, the scientists cultured Xenopus laevis pre-migratory NC (pre-mig NC) previous to the process of EMT and these cells were compared with the migratory NC (mig NC) after they underwent EMT. About 80% of cell-to-cell collisions in Mig-NC exhibited CIL while only 40% Pre-mig-C showed CIL after collisions. The nucleus of Pre-mig cells remained at short cell-to-cell distance. The NC explants have been shown to undergo EMT in vitro in the migratory stages (Kuriyama, 2014).
2) The researchers also did an analysis of the cell junctions during the CIL. For this, the hypothesis proposed by the researchers was that the difference in behavior shown by pre-mig and mig NC as response to the cell-to-cell interactions might be due to junction formation differences. For this part, p-120-GFP also known as (-Catenin-GFP was expressed in both Mig-NC and Pre-mig-NC.
Though the response of CIL was not...