Euglena Co., Ltd. and Professor Masaaki Tamura of Kansas State University in the U.S. have confirmed the possibility that the inhibition of lung cancer growth via intestinal microflora by extracts of microalgae Euglena powder is caused by induction of apoptosis of cancer cells by short chain fatty acids produced by the intestinal microflora The results of this study were published in the Journal of the American Cancer Society in 2023. The research results were published in the online edition of "Integrative Cancer Therapies" on August 30, 2023.
https://journals.sagepub.com/doi/10.1177/15347354231195323

Apoptosis is a controlled and regulated cell death that is actively induced to keep the individual in a better state.

Purpose of the Study
　Lung cancer is known as the disease with the highest incidence and mortality rate among cancers. Although smoking has been reported as a cause of lung cancer, exposure to toxic substances such as asbestos (asbestos), chromium, and radon, as well as air pollution such as PM2.5 are also possible causes. In addition, lung cancer tends to metastasize to other organs, and lung cancer is often caused by the metastasis of cancer in other organs, which calls for measures for prevention and treatment.
　Euglena has published research results that suggest that aqueous extract of Euglena suppresses the growth of lung cancer in mice via immunity, and that changes in the intestinal microflora are involved in the suppression of lung cancer growth in mice by Euglena extract through verification using fecal transplants and antibiotic treatment. The research results suggest that changes in the intestinal microflora are involved in the inhibition of lung cancer growth in mice by Euglena extracts. In this experiment, we used a mouse model in which lung cancer was induced using a tobacco-specific carcinogen, which is more similar to the mechanism of human lung cancer development, to examine the mechanism in more detail.

Contents and Results of Research
Oral intake of Euglena extract inhibited lung cancer growth
　The following three groups were prepared and compared in terms of the number of tumor nodules*5 in lung cancer induced by tobacco-specific carcinogens. Euglena extract was mixed with drinking water and ingested.
1) Mice with lung cancer induced without ingestion of euglena extract
2) Mice in which lung cancer was induced after daily ingestion of euglena extract for 2 weeks and continued ingestion for another 19 weeks
3) Mice that were given daily intake of euglena extract for 9 weeks after 10 weeks of induced lung cancer

　As a result, the number of tumor nodules of lung cancer was significantly reduced in both 2) pre group and 3) post group compared to 1) control group.

Oral intake of Euglena extract increased short-chain fatty acid production by intestinal microflora

　The concentration of short-chain fatty acids (acetic acid, butyric acid, and propionic acid) in the feces of control, pre, and post group mice was measured. As a result, acetic acid levels were significantly higher in both the pre- and post-groups compared to the control group (Figure 2 A), and in the post-group, propionic acid and butyric acid levels were significantly higher (Figure 2 B and C).

　These results indicate that the intake of euglena extract increased the production of short-chain fatty acids by the intestinal microflora.

Short-chain fatty acids inhibit lung cancer growth via induction of apoptosis
　To clarify the involvement of short-chain fatty acids (acetic acid, butyric acid, and propionic acid) in the lung cancer inhibitory effect of euglena extract, we conducted experiments using lung cancer cells. Acetic acid, butyric acid, and propionic acid were added to lung cancer cells, respectively, and after 48 hours of culture, the percentage of apoptosis of lung cancer cells was measured using flow cytometry. The results showed that the addition of butyric acid in particular increased the apoptosis rate of lung cancer cells compared to the control (Figure 3).

Flow cytometry is a laser-based technique for counting, sorting, and characterizing cells in heterogeneous mixtures, allowing rapid and simultaneous analysis of the physical and scientific properties of individual cells and particles, and of multiple parameters

　The above results indicate that the lung cancer inhibitory effect of euglena extract via the intestinal microflora, which we have confirmed so far, may be caused by short-chain fatty acids produced by the intestinal microflora inducing apoptosis of cancer cells.

　Euglena Co., Ltd. will continue our research and development with the aim of further elucidating the potential of euglena to support the body's natural cycle of "create, work, and protect," and to utilize euglena and its components in the health food and medical fields, as well as to enhance its added value as a food ingredient.