Luciferase Reporter Cell Line - KYSE-150

Mounting evidence suggests that exosomes are involved in cancer progression. However, the functions of proteins delivered by cancer cell exosomes have been poorly investigated. Previous studies have shown that overexpression of serine protease (SRGN) promotes invasion and metastasis of esophageal squamous cell carcinoma (ESCC) cells. Here, researchers investigated the paracrine effects of exosomes derived from SRGN-overexpressing ESCC cells (SRGN Exo) on ESCC cell invasion and tumor angiogenesis, and identified the relevant exosomal proteins using mass spectrometry. The results showed that cation-dependent mannose-6-phosphate receptor (M6PR) and Ephrin type B receptor 4 (EphB4) were significantly upregulated in SRGN Exo. Upregulated exosomal M6PR mediated the pro-angiogenic effects of SRGN Exo in vitro and in vivo, while upregulated exosomal EphB4 mediated the pro-invasive effects of SRGN Exo on ESCC cells in vitro. Furthermore, in vitro studies showed that regulating M6PR expression affects the viability and migration ability of esophageal squamous cell carcinoma (ESCC) cells. The expression levels of both M6PR and EphB4 were positively correlated with the expression of SRGN in the serum of ESCC patients. Elevated serum M6PR levels were associated with decreased overall survival. These studies confirm that exosomal M6PR and EphB4 play important roles in tumor angiogenesis and malignant progression, and that serum M6PR is a novel prognostic biomarker for ESCC patients.

Here, six-week-old female nude mice were injected weekly via tail vein with 7 × 10⁸ cells of KYSE150-Con Exo or KYSE150-SRGN Exo for 4 weeks. The control group received only PBS. On day 7 after the last injection, 5 × 10⁵ cells of luciferase-expressing KYSE150 cells (KYSE150-luc) were injected via tail vein. Five weeks later, D-luciferin was injected intraperitoneally, followed by bioluminescent imaging to assess lung metastasis. In vivo experimental metastasis analysis showed that esophageal squamous cell carcinoma (ESCC) cells pretreated with circulating SRGN Exo showed significantly greater lung metastasis compared to the Con Exo group (Figure 1). These results indicate that SRGN Exo can mediate the invasive phenotype to transfer to other ESCC cells in vitro and promote in vivo metastasis.

Figure 1. Effect of SRGN Exo on the colonization of KYSE150-luc cells to lungs of nude mice. (Yan D, et al., 2023)