Oleic Acid in Cell Culture

Importance and uses of oleic acid in serum-free eukaryotic, including hybridoma and Chinese Hamster Ovary (CHO) cell, cultures

Oleic acid, a Serum-Free Medium Supplement, Useful In Biomanufacturing; Tissue Engineering and Specialty Media:

Fatty acids of the n-3, n-6 and n-9 families are important supplements for cell culture systems. They are important in cell culture systems used to biomanufacture heterologous proteins, such as monoclonal antibodies. Fatty acids have been shown to be important for the growth and productivity of Chinese Hamster Ovary (CHO) cells.

In animal cells, oleic (18:1, n-9) acid is created by the dehydrogenation of stearic acid. Oleic acid is further elongated and desaturated into a family of n-9 fatty acids. Historically, oleic acid and its precursors have been provided to cells in culture as components of serum, albumin or esterified to molecules such as cholesterol. Oleic acid is poorly soluble in aqueous media and susceptible to peroxidation. The advent of serum-free, animal-protein-free and protein-free media formulations has increased the difficulty of delivering oleic acid to cells in culture.

The proper formulation of oleic acid as a stable supplement is a challenge for the development of proprietary media useful for biomanufacturing and tissue engineering.

Primary Functions of Oleic Acid in Cell Culture Systems:

• Long-term energy storage: energy derived from NADPH and ATP is stored in fatty acids. Fatty acids are esterified to a glycerol backbone to form a group of compounds known as mono-, di- and tri- glycerides (neutral fats). Energy is released when fatty acids are degraded.
• Fatty acids are precursors of other molecules: prostaglandins, prostacyclins, thromboxanes, phospho-lipids, glycolipids, and vitamins.
• Structural elements: fatty acids are important constituents of cell structures such as the membranes.

Chemical Attributes of Oleic Acid that make it a Useful Serum-Free Medium Supplement:

Fatty acids (FA) are long-chain carboxylic acids that are insoluble in water. These fatty acid chains can be from 4 to 30 carbons long, but physiologically the most important fatty acids are from 16 to 22 carbons long. Since fatty acids are synthesized naturally by the addition of acetyl groups, they have an even numbers of carbon atoms-C2, C4, etc. They can be saturated or unsaturated. Natural fatty acids have their double bonds in the cis-configuration and are usually esterified to glycerol backbones to form complex lipids. Fatty acids that contain more than one double bond are called polyunsaturated fatty acids (PUFAs).

In animals, most fatty acids with 16 or more carbons belong to one of three main fatty acid families. All unsaturated members of a family are n-3, n-6, or n-9. Members of these FA families are not inter-convertible. Palmitic acid family; palmitic acid is saturated, but unsaturated fatty acids derived from it are of the n-9 type. Animal cells can de novo synthesize palmitic fatty acid and its n-9 derivatives. However, de novo synthesis requires the utilization of energy. Palmitic acid (16:0) is a precursor of stearic acid (18:0). Palmitic acid can also be dehydrogenated to form palmitoleic acid (16:1, n-9). A number of other important fatty acids are derived from palmitoleic acid. In animal cells, oleic (18:1, n-9) acid is created by the dehydrogenation (desaturation) of stearic acid. Oleic acid is further elongated and desaturated into a family of n-9 fatty acids. If oleic acid is not provided in sufficient quantity, cells cannot produce other important fatty acids, and fatty acid derivatives.