The research tool: PlasmaxTM
PlasmaxTM is a physiologically relevant cell culture medium that closely resembles the metabolic and nutritional profile of human plasma. Unlike traditional media designed to supply excessive levels of a few nutrients, it provides unmatched metabolic fidelity.
CancerTools.org spoke with Dr. Tardito about PlasmaxTM to explore the importance of its development and what its contribution to the CancerTools.org initiative can do for cancer research.
The contributor
Cancer Research UK Glasgow: The Beatson Institute
The future of cell culture media
Cell culture media is a critical component of cell-based assays, but its contribution to results is often overlooked. The right cell culture is critical in order to comprise the correct energy and compounds to regulate and support the cell cycle. For in vitro experiments, scientists typically use media like Dulbecco’s Modified Eagle Medium (DMEM) – a mixture of vitamins, selected amino acids, sugars and salts which sustain cellular growth. Yet, such types of mediums typically focus on cell proliferation rather than the nutritional environment that cells withstand in tumours. Dr. Tardito, an oncometabolism expert from the CRUK Beatson Institute, required a cell culture medium which better reflected human physiological conditions in order to study cancer biology.
Overcoming in vitro and in vivo variance
Traditional cell culture media was originally produced to rapidly and successfully increase cell proliferation in an in vitro environment (Eagle, 1955). This was made possible by adding nutrients in excessive concentrations to avoid nutrient depletion and simultaneously promote cell growth. Such disproportionate nutrient composition, in comparison to in vivo conditions like human plasma, affects both phenotypic and genotypic behaviour of cells (Schug et al, 2015 and Tardito et al, 2015). Usage of traditional media for cell culture can therefore lead to unrepresentative in vitro conditions and variance between in vitro and in vivo cancer cell metabolism. This becomes particularly important in research relating to cancer cell biology and related metabolic pathways.
To address this challenge, the research team at the Beatson Institute for Cancer Research, Glasgow, UK, under the supervision of Dr. Saverio Tardito, developed a novel cell culture medium, PlasmaxTM, to study the cell metabolism in different tumour types.
”The clear cut differences between experiments performed with Plasmax vs commercial media available at the time become obvious once you realise, they aren’t physiologically relevant
Dr. Tardito
The development of PlasmaxTM
Dr. Tardito and his research team, optimised the concentrations of over 80 compounds typically found in human plasma to achieve the cell growing conditions. The cell culture medium contains all relevant elements to mimic human plasma, consisting of proteinogenic amino acids, vitamins, salts, and sugars, determined through Dr.Tardito’s optimisation experiments. The inclusion of metabolites enhances its physiological relevance and thereby mimics the in vivo environment. Trace elements, while essential for survival and proliferation, are often missing from traditional cell culture media and have to be supplemented before use. PlasmaxTM, is uniquely formulated with trace elements including vanadium, zinc, manganese, copper and selenium. The presence of these increase the antioxidant capacity of cells, which promotes colony growth by preventing ferroptosis-induced cell death (VandeVoorde et al., 2019).
Benefits of PlasmaxTM
It is critical for biomedical research to renew and refine models to improve their relevance to human physiology – which is exactly what the development of PlasmaxTM helps to execute.
PlasmaxTM has been successfully validated across primary cells of different tissue, species, and experimental conditions (see Table 1), and is suitable for both primary and established cell lines. Additional cell lines are successfully cultured using PlasmaxTM regularly, which makes Table 1 a running list of validated cell lines. PlasmaxTM is anticipated to work across a broad range of cancer cell culture models.
Using a physiological relevant medium significantly impacts the results obtained from common cellular assays, including colony formation and gene expression. This has the potential to improve results for cancer cell biology experiments associated with drug discovery and in vitro cancer models.
”Using physiologically relevant media is a time saver and will make you more confident in your data.
Sunada Khadka
Physiologically relevant
PlasmaxTM is optimised to reflect the in vivo profiles of nutrients and metabolites found in human plasma, including essential and non-essential amino acids, amino acid derivatives, organic acids, and other polar metabolites.
Improves in vitro metabolic fidelity
PlasmaxTM can better approximate the overall metabolic phenotype of tumours, with both 2D and 3D cells cultured in PlasmaxTM, better recapitulating the tumours’ metabolic signatures.
By increasing the metabolic fidelity and biological relevance of in vitro cancer models, better drug discovery and improved understanding of cancer at a cellular level can ensure.
Produces a faster proliferation
When compared with traditional mediums, PlasmaxTM produces a faster proliferation, even when aged up to 12 months, in comparison with DMEM when both are supplemented with 2.5% foetal bovine serum.
Better mimics tumour metabolism
PlasmaxTM better mimics tumour metabolism. Breast cancer spheroids grown in PlasmaxTM , have shown to better approximate the metabolic profile of mammary tumours (Vande Voorde et al., 2019).
Uncover role of trace elements
Cancer cells seeded at low densities in the absence of the trace element selenium are unable to form colonies in traditional media due to lipid peroxidation and ferroptosis. The growth-enabling trace elements in addition to vitamins and inorganic salts in PlasmaxTM, prevent ferroptosis-induced cell death, and promote colony growth.
Table 1: A selected list of cultured cell lines successfully validated for growth and viability in PlasmaxTM under standard conditions
| Cell lines grown in Plasmax TM | Tissue of origin | Cell line status | Species |
| HepG2 | Liver Cancer | Established line | Human |
| HuH7 | Liver Cancer | Established line | Human |
| HuH6 | Liver Cancer | Established line | Human |
| BT549 | Breast Cancer | Established line | Human |
| MDA-MB-468 | Breast Cancer | Established line | Human |
| Cal120 | Breast Cancer | Established line | Human |
| A375 | Melanoma | Established line | Human |
| Colo829 | Melanoma | Established line | Human |
| LN18 | Brain Cancer | Established line | Human |
| Naive glioblastoma cell line | Brain Cancer | Low passage lines | Human |
| Dermal fibroblasts | Epidermis | Primary | Human |
| Small intestine organoid | Small intestine | Primary | Mouse |
| Mammospheres | Mammary gland | Primary | Mouse |
| Mesenchimal stromal cell line | Bone marrow | Primary | Human |
| Embryonic stem cell line | Embryo | Primary | Human |
| Trophoblast stem cell line | Placenta | Primary | Human |
| A549 | Lung cancer | Established line | Human |
| HCT116 | Colon Cancer | Established line | Human |
| SaOS2 | Bone tumour | Established line | Human |
| HT1080 | Fibrosarcoma | Established line | Human |
Plasmax impact
Choosing an appropriate cell culture medium is a crucial step in in vitro cell biology research and finding the correct one for your cell type and experiment can be challenging. Such was experienced by Sunada Khadka, a PhD Candidate at MD Anderson, during her research on anaplerosis in glioma cells.
While using a traditional medium, Sunada’s initial results obtained in vitro were not reproduced in her in vivo experiments. This inconsistency in data led to a return to in vitro experimental conditions and a closer examination of the cell culture media used. PlasmaxTM was selected as a cell culture media that better reflected the in vivo nutrient profile. By comparing in vitro results from PlasmaxTM to DMEM, Sunada was able to understand the discrepancy, illuminating the importance of triaging cell culture media with physiologically relevant media like PlasmaxTM in order to better recapitulate the in vivo environment.
”In the future, whatever metabolism related work I do, I'll make sure to compare DMEM to Plasmax to ensure that the nutrient profile is not effecting the certain phenotype that I’m seeing
Sunada Khadka
Conclusion:
Optimising the relevant components in culture media and defining their physiological concentrations at scale, can be a challenging process. Having PlasmaxTM in a pre-prepared liquid form saves time, effort, initial investment of sourcing, and spares the process of optimising 80+ components to get their proportions accurate.
PlasmaxTM unique formula, maintains its effectiveness throughout its shelf life with no effect on cell growth from being aged. It is compatible across different cell types and is greatly beneficial to any cancer researcher interested in the study of cancer cell biology, in vitro cancer models and cell based assays.
PlasmaxTM is already being repeatedly purchased by various cancer researchers across different academic institutes worldwide.
