The Leukemic Stem Cell Niche: Adaptation to “Hypoxia” Versus Oncogene Addiction

Hematopoietic stem cells (HSC) are responsible for constantly maintaining and replenishing the supply of new blood and immune cells. They give rise to both lymphoid and myeloid progenitor cells, which then proceed to differentiate down their respective paths to form various specialized cells such as erythrocytes, macrophages, B and T cells, to name a few. Within the body, HSCs are found to reside in extremely low oxygen environments called stem cell niches (SCN). Like all other regulated cell cycles, HSCs can lead to cancers such as leukemia and lymphoma if cell division becomes uncontrolled.

MEL (a), Kasumi-1 (b), or NB4 (c) cells were incubated in atmosphere at 0.1% O2 and lysed at the indicated times, and total cell lysates were subjected to immunoblotting with the indicated antibodies. GAPDH, H4, or ARD1 were detected to verify loading equalization. Migration of molecular weight markers is indicated on the left (kDa). For each cell population, one out of three independent experiments with similar outcome is shown.

Figure 2: Suppression of oncogenic proteins driving non-CML blood neoplasias in the course of cell “adaptation to hypoxia.” MEL (a), Kasumi-1 (b), or NB4 (c) cells were incubated in atmosphere at 0.1% O2 and lysed at the indicated times, and total cell lysates were subjected to immunoblotting with the indicated antibodies. GAPDH, H4, or ARD1 were detected to verify loading equalization. Migration of molecular weight markers is indicated on the left (kDa). For each cell population, one out of three independent experiments with similar outcome is shown.

In this paper, Cheloni et al. primarily focused on chronic myeloid leukemia (CML).

The authors hypothesized that suppression of the BCR-Abl oncogene is likely a key positive regulator of LSC survival within “hypoxic” SCNs. To analyse the various mechanisms and responses that CML cells demonstrate within SCNs, the authors studied correlations between varied oxygen and glucose concentrations with the amount of BCR-Abl produced. All tests were performed using two human CML cell lines, K562 and KCL22. Testing conditions were precisely controlled to mimic the SCN environment as close as possible. Using a Hypoxystation supplied by Don Whitely Scientific, a water-saturated atmosphere comprising of 0.1% O2, 94.9% N2 and 5% CO2 was generated and maintained.

The research conducted and documented by Cheloni et al. has provided great insight into several key regulatory mechanisms associated with leukemic stem cells as well as an explanation for their notorious reputation for having high relapse rates. Additionally, they established that the triggering of oncogene suppression associated with CML is due to severe energy restriction rather than simply the “adaptation to hypoxia.”

The Don Whitley Scientific Hypoxystation provides the user incredible flexibility as it can control oxygen down to 0.1% while providing a temperature and humidity controlled environment with ample working space. The extreme precision provided by the Hypoxystation was critical to the collection of accurate and reliable data when recreating the demanding environment that comprises SCNs. The atmosphere is constantly monitored and adjusted by the real-time feedback system to ensure accuracy and ISO class 3 clean room HEPA filtration is also available for long term cell culture applications.

Choose your atmosphere with the Hypoxystation hypoxia chamber. Accurately control O₂, CO₂, Temperature and Humidity.

Hypoxystation is the only hypoxic chamber purpose built for physiological cell culture research. Specifically designed to create normoxic, hypoxic and anoxic conditions within a controlled and sustained workstation environment, this hypoxic incubator is ideal for research requiring the ability to accurately control O₂, CO₂, temperature and humidity. The Whitley Internal HEPA Filtration System provides a particle-free internal environment that exceeds ISO 14644 class 3 clean atmosphere. With such accurate control and the ability to manipulate cells in situ without altering the incubation environment, research into cell biology can be performed over a comprehensive range of oxygen tensions with precision. Don Whitley Scientific offer the following range of Hypoxystations:

i2 Instrument Workstation

Application possibilities for Hypoxystation are endless; it is being used for research into tumour microenvironment, hypoxia pathways and HIF signalling, in vitro modelling of in situ environments, cancer cell metastasis, angiogenesis, and many other fields where cells may benefit from a more physiological atmosphere.