Improving Cancer Drug Screening with 3D Cell Culture

Differential contrast image of HCT116 colon cancer spheroid grown in a 96-well hanging-drop platform after seeding with 800 cells. Copyright Promega Corporation.

Differential contrast image of HCT116 colon cancer spheroid grown in a 96-well hanging-drop platform after seeding with 800 cells. Copyright Promega Corporation.

Tissue culture using primary or cultured cell lines has long been a mainstay of testing compounds for inhibiting cell growth or promoting apoptosis during screening for cancer drugs. However, the standard culture conditions result in monolayers of cells, dividing and growing across the bottom of a well, plate or flask in a single layer. The drawback of this technique is that organisms do not come in monolayers; a three-dimensional (3D) spheroid is closer to the in vivo state, especially if the spheroids are made up of more than one cell type like tumors in multicellular organisms. Even more beneficial would be using 3D cultured cells in high-throughput screening to facilitate compound profiling for target effectiveness and cytotoxicity. In a recent PLOS ONE article, researchers used normal and breast cancer cells both in monoculture and coculture to test a set of compounds and found results differed between 2D and 3D cultured cells. Continue reading

Screening for Antiviral Compounds under Level 4 Containment Conditions

BiohazardWorking with bacteria and viruses that cause life-threatening diseases with no currently available treatment options takes guts. Most scientists are familiar with the routine requirements of good aseptic technique, are highly aware of laboratory safety requirements, and are more than familiar with autoclaves and sterilization issues, but if we make a mistake the consequences are usually only lost time or a spoiled experiment—not a lost life.

Scientists working with highly virulent organisms deal with a whole other level of risk that requires adherence to the strictest of safety regulations, and these containment regulations can sometimes place constraints on the type of experiment that can be performed with dangerous pathogens. A paper published in the April issue of Assay and Drug Development Technologies brought this to my attention and reminded me of the serious issues some scientists face on a daily basis as they research ways to combat infectious diseases. Continue reading

Considerations for Successful Cell-Based Assays 3: Treatment Parameters

Welcome to the third installment of our series on cell-based assays. Designed for the newbie to the world of cell-based assays, we have covered the topics of choosing your cell type and basic cell culture tips in the previous posts. In this post, we will discuss how decisions about test compound treatment: how much and how long can affect assay results and interpretation. Continue reading

When the Writing Gets Tough, the Tough Write about Semicarbazide-Sensitive Amine Oxidases

These are the cranes I saw while walking and thinking about SSAOs.

When you hold a position as a scientific communication specialist at a biotech company, you never know what you are going to need to write. Most of the time I really like the fact that I have to master new subject matter on a daily basis. I’m using my degree and my brain, and articulating science in a way that connects with the reader is incredibly rewarding. It’s why I do what I do.

However, when I was asked to write about a new assay for semicarbazide-sensitive amine oxidases (SSAOs), my enthusiasm waned. This is a subject about which I know nothing, so I searched the literature to learn as much as I could. After reading several review articles I was able to write this scintillating paragraph: Continue reading

A Scalable and Sensitive Assay for HDAC Activity

Dysfunction of histone deacetylases (HDACs) is associated with many diseases including cancers, asthma and allergies, inflammatory diseases and disorders affecting the central nervous system. Because of their involvement in such a wide range of pathologies, HDACs have become a target for drug discovery. Traditional HDAC activity assays are either isotopic or fluorescent assays using artificial substrates that are prone to artifacts or fluorescence interference. There is a need for a functional assay that is sensitive, accurate and amenable to drug-screening activities.

A recent paper by Halley et al. in the Journal of Biomolecular Screening describes the evaluation of a bioluminogenic HDAC assay, the HDAC-Glo™ I/II and SIRT-Glo™ Assays. Continue reading

Tips for Multiplex Cell-Based Assay Success

The ability to analyze more than one cellular biomarker in a single sample is advantageous for a number of reasons. Multiplexing allows researchers to save money and time, while conserving precious samples. In addition, understanding the relationship between cell biomarkers can provide a more complete picture of cell health that can lead to improved predictive models for drug discovery. Understanding biomarker relationships can also minimize ambiguity in the data set and validate if a treatment effect is real or an artifact of the system. To avoid repeat experiments and extract the most biologically relevant data from multiplex assays, consider these tips when performing multiplex cell-based assays.
Continue reading

Describing Life and Death in the Cell

4621CALife is complicated. So is death. And when the cells in your multiwell plate die after compound treatment, it’s not enough to know that they died. You need to know how they died: apoptosis or necrosis? Or, have you really just reduced viability, rather than induced death? Is the cytotoxicity you see dose-dependent? If you look earlier during drug treatment of your cells, do you see markers of apoptosis? If you wait longer, do you observe necrosis? If you reduce the dosage of your test compound, is it still cytotoxic? Continue reading