Identification of active components in Andrographis paniculata targeting on CD81 in esophageal cancer in vitro and in vivo.

BACKGROUND: Esophageal cancer (EC) is highly prevalent in Eastern Asia (including China) with high rates of mortality. The metastatic tendency in EC is associated with a poor prognosis. Our previous studies have demonstrated the suppressive effects of Andrographis paniculata water extract (APW) on metastatic esophageal cancer in vitro and in tumor-bearing mice models, as well as illustrated the potential underlying mechanism by transcriptome analysis. HYPOTHESIS: High expressions of several membrane protein tetraspanins were reported to lead to a high risk of metastasis in esophageal cancer in patients. We hypothesized that APW could downregulate the expression of tetraspanin CD81 in esophageal cancer cells and xenografts. METHODS: Human esophageal cancer cells EC109 and KYSE520 were incubated with APW for 24 hours in cell culture, while mice bearing EC109 xenograft tumors were treated with APW for 21 days. The expressions of CD81 in cancer cells and in tumors from mice were evaluated. Molecular docking and microscale thermophoresis analyses were applied to identify the components in APW interacting with CD81. The influence of the identified components on CD81 expression was further evaluated in EC109 cells. RESULTS: APW could significantly suppress the expressions of CD81 in both EC109 and KYSE520 cells in a concentration-dependent manner. Treatment of APW in xenograft-bearing mice reduces the metastasis in lungs, livers, and lymph nodes. The expression of CD81 in xenograft tumors of APW-treated mice was significantly lower than those of untreated control mice. The binding of andrographolide, bisandrographolide A, and bisandrographolide C with CD81 were elucidated by microscale thermophoresis. The suppressive effects of these compounds on the motility of EC109 cells, as well as CD81 protein and mRNA expressions, were further confirmed. CONCLUSION: This is the first time to demonstrate that andrographolide, bisandrographolide A, and bisandrographolide C, which are present in APW, bind to CD81 and suppress its function. These compounds are likely to be responsible for the anti-metastatic activities of APW in esophageal cancer.

Discovery of an interplay between the gut microbiota and esophageal squamous cell carcinoma in mice.

Esophageal squamous cell carcinoma (ESCC) is the main type of esophageal cancer (EC) worldwide, causing half a million deaths each year. Recent evidence has demonstrated the role of the gut microbiota in health and disease. However, our current understanding of the gut microbiome in EC remains scarce. Here, we characterized the gut and esophageal microbiome in a metastatic mouse model of ESCC and examined the functional roles of the gut microbiota in EC development in fecal microbiota transplantation (FMT) experiments. Nude mice intraperitoneally xenografted with human EC-109 cells showed significant alterations in the overall structure, but not alpha diversity, of the gut and esophageal microbiome as compared to naïve control mice. Xenograft of EC cells depleted the order Pasteurellales in the gut microbiome, and enriched multiple predicted metabolic pathways, including those involved in carbohydrate and lipid metabolism, in the esophageal microbiome. FMT of stool from healthy mice to antibiotic-treated xenograft-bearing mice significantly attenuated liver metastasis, suggesting a protective role of the commensal gut microbiota in EC. Moreover, we showed that combination chemotherapy with cisplatin and 5-fluorouracil, and the anti-EC medicinal herb Andrographis paniculata (AP) differentially affected the gut and esophageal microbiome in EC. FMT experiment revealed a reduced anti-metastatic efficacy of AP on liver metastasis in antibiotic-treated xenograft-bearing mice, suggesting a role of the commensal gut microbiota in the anti-metastatic efficacy of the herb. In conclusion, our findings reveal for the first time an interplay between the gut microbiota and EC and provide insights into the treatment strategies for EC.