IL6pro-Luc/EF1α-mCherry Reporter Cell Line - TE-1

Interleukin-6 (IL-6) is a pleiotropic cytokine that acts as a bridge between inflammation and tumor progression. Secreted IL-6 binds to the IL-6 receptor and gp130, triggering the activation of JAK1 and JAK2, which subsequently activate STAT3; it also stimulates the MAPK and PI3K/AKT signaling pathways. In esophageal squamous cell carcinoma (ESCC), IL-6—produced either via autocrine signaling or by stromal cells—is closely linked to tumor cell proliferation, epithelial-mesenchymal transition (EMT), invasion, and resistance to chemotherapy and radiotherapy. Among commonly used ESCC cell lines, TE-1 cells exhibit a relatively high basal level of IL-6 expression. The transcription of IL-6 is governed by a promoter that integrates various inflammatory signals and contains functional binding sites for NF-κB, AP-1 (c-Fos/c-Jun), and C/EBPβ. The IL6pro-Luc/EF1α-mCherry reporter cell line (derived from TE-1 cells) features the human IL-6 promoter placed upstream of the firefly luciferase gene, allowing promoter activation to be directly monitored via bioluminescence. Furthermore, this cell line constitutively expresses the mCherry marker and a puromycin resistance gene under the control of the EF1α promoter; the resulting red fluorescent signal enables the monitoring of cell numbers, independent of the signaling pathways being studied.

This cell line can be used to assess IL-6 promoter activity in esophageal cancer cells and to screen for drugs capable of inhibiting inflammation-associated transcription. A typical experimental workflow involves stimulating cells with LPS, TNF-α, IL-1β, or PMA to induce promoter activity, followed by testing inhibitors of the NF-κB, AP-1, or JAK/STAT3 signaling pathways—all of which ultimately converge on the regulation of IL-6. Alternatively, one can knock down upstream regulators such as c-Jun, c-Fos, or C/EBPβ to observe any resulting attenuation in signaling. This cell line is suitable for screening natural products with anti-inflammatory activity (e.g., matrine, which inhibits IL-6 transcription in TE-1 cells via the AP-1 axis) as well as compounds capable of restoring chemosensitivity (given the role of the IL-6/STAT3 loop in cisplatin resistance). Furthermore, this reporter system can be used to investigate the autocrine feedback loop between tumor-derived IL-6 and STAT3 activation. Since the mCherry channel operates independently of the signaling pathways, this cell line is well-suited for high-throughput screening in 96-well or 384-well formats, eliminating the need for repeated transient transfections across different dosage conditions or cell passages.