Cell proliferation assays have a wide range of applications in scientific research – from testing drug reagents to the effect of growth factors, from testing cytotoxicity to analyzing cell activity. So, what are cell proliferation assays? Cell proliferation assays typically detect changes in the number of cells in a division or changes in a cell population.
In some ways, the heart is quite a vulnerable organ. Cardiac complications such as heart attack, cardiac arrest, or heart failure are common. But interestingly, of the many diseases that may affect the heart, cancer is not one of them. For example, we often hear about cancer in the prostate, breast, colon, skin, etc., but rarely of the heart. How is this vital organ different?
The Problem with Cancer Models
Very few cancer drugs succeed in clinical trials, despite showing promise in the lab. Treatments that may work on animal models, cell lines, or even patient-derived xenografts often do not have the same efficacy in patients. The underlying reason is tumor environments within the human body are far more complex than in research models. For example, the tissue structure (histological complexity) and genetic heterogeneity of an animal model is different than that of humans. Even cell lines and patient-derived xenografts, which are human-derived, have their own pitfalls such as genetic mutations and animal-specific tumor evolution, respectively. Due to the inability to reproduce human tumor environments, many drugs fail clinical trials after lengthy and costly development.
The Hippo signal is very conservative in evolution. It regulates organ size and tissue stability by regulating cell proliferation, apoptosis, and stem cell renewal. The core process of Hippo signaling is a kinase tandem process, Mst1/2 and Sav1 form a complex, phosphorylate and activate Lats1/2; Lats1/2 kinase then phosphorylates and inhibits transcriptional coactivators Yap and Taz. Yap and Taz are the most important effectors downstream of the Hippo pathway. Upon dephosphorylation, Yap and Taz translocate to the nucleus and interact with TEAD1-4 or other transcription factors (such as CTGF) to induce gene expression, thereby initiating cell proliferation and inhibiting apoptosis.
Long-interspersed nuclear elements (LINEs) are genetic components found in higher eukaryotes. They are retrotranposons, meaning that they are transcribed into mRNA and then translated into proteins that act as a reverse transcriptase. The reverse transcriptase makes a copy of the LINE DNA which can then be integrated into the genome at a new site. The only active LINE in humans is LINE-1. It has been associated with oncogenesis and Haemophilia A, a diseased caused by insertional mutagenesis.
ERK1/2 (MAPK1/MAPK3, p44/42MAPK) are members of the mitogen-activated protein kinase family (MAPKs) that are commonly located in the cytoplasm. They act as catalysts in the phosphorylation of serine/threonine and are negatively regulated by the bispecific (Thr/Tyr) MAPK phosphatase family (called DUSP or MKP) and MEK inhibitors (such as U0126 and PD98059).