Similarities and differences in metabolites of tongue cancer cells among two‐ and three‐dimensional cultures and xenografts

• Published in: Cancer science 2021-02, Vol.112 (2), p.918-931
• Main Authors: Murakami, Shoko, Tanaka, Hiroyuki, Nakayama, Takahisa, Taniura, Naoko, Miyake, Toru, Tani, Masaji, Kushima, Ryoji, Yamamoto, Gaku, Sugihara, Hiroyuki, Mukaisho, Ken‐ichi
• Format: Article
• Language: English
• Subjects: Animals; Blood flow; Cancer; cancer metabolism; Cancer therapies; Carcinoma, Squamous Cell - metabolism; Carcinoma, Squamous Cell - pathology; Cell culture; Cell Culture Techniques; Cell Line, Tumor; Dehydrogenases; Glycolysis; Head & neck cancer; Heterografts; Humans; Male; Metabolites; Mice; Mice, Inbred BALB C; Mice, Nude; Mitochondria; mitochondrial function; Nutrients; Oral carcinoma; Organoids - metabolism; Organoids - pathology; Original; Principal components analysis; Spheroids, Cellular - metabolism; Spheroids, Cellular - pathology; Statistical analysis; Stromal cells; three‐dimensional; tissueoid cell culture system; Tongue; tongue cancer; Tongue Neoplasms - metabolism; Tongue Neoplasms - pathology; Tumor cell lines; Tumors; Xenografts
• ISSN: 1347-9032; 1349-7006
• DOI: 10.1111/cas.14749

Metabolic programming of cancer cells is an essential step in transformation and tumor growth. We established two‐dimensional (2D) monolayer and three‐dimensional (3D) cultures, the latter called a “tissueoid cell culture system”, using four types of tongue cancer cell lines. We also undertook a comprehensive metabolome analysis of three groups that included xenografts created by transplanting the cell lines into nude mice. In addition, we undertook a functional analysis of the mitochondria, which plays a key role in cancer metabolism. Principal component analysis revealed the plots of the four cell lines to be much narrower in 2D culture than in 3D culture and xenograft groups. Moreover, compared to xenografts, the 2D culture had significantly lower levels of most metabolites. These results suggest that the unique characteristics of each cell disappeared in 2D culture, and a type of metabolism unique to monolayer culture took over. Conversely, ATP production, biomass synthesis, and maintenance of redox balance were shown in 3D culture using sufficient nutrients, which closely resembled the metabolic activity in the xenografts. However, there were several differences between the metabolic activity in the 3D culture and xenografts. In vivo, the cancer tissue had blood flow with stromal cells present around the cancer cells. In the xenografts, we detected metabolized and degraded products in the liver and other organs of the host mice. Furthermore, the 3D system did not show impairment of mitochondrial function in the cancer cells, suggesting that cancer cells produce energy simultaneously through mitochondria, as well as aerobic glycolysis. Significant differences in the metabolism of tongue cancer cells between 2D and 3D cell cultures were found. Many metabolites in the 3D culture were similar to those in the xenografts. These results suggest that the unique characteristics of each cell disappeared in 2D culture, and a type of metabolism unique to monolayer culture took over.