The effect of ephrin-A1 on resistance to Photofrin-mediated photodynamic therapy in esophageal squamous cell carcinoma cells

Abstract

Esophageal squamous cell carcinoma (ESCC), the most prevalent cell type of esophageal cancer, remains a dismal disease with poor prognosis. Photodynamic therapy (PDT) is a minimally invasive treatment option for early esophageal cancer. To explore possible factors involved in resistance to PDT in esophageal cancer cells, we selected PDT-resistant subcell lines by repeated treatment of CE48T/VGH (CE48T) ESCC cells with Photofrin-PDT and then analyzed the global gene modulations in the PDT-resistant cells by whole-genome microarray. More than 700 genes reached a fold change greater than 1.5 in each of the PDT-resistant cells compared to parental cells. Among these genes, both tumor necrosis factor (TNF) and EFNA1 genes were significantly upregulated in resistant cell lines. However, they were significantly downregulated in Photofrin-PDT-treated cells compared to untreated cells. The observations made in the microarray analysis were further confirmed by quantitative PCR. We observed that recombinant tumor necrosis factor alpha (TNF-α) activated the gene expression of EFNA1 at both the messenger RNA (mRNA) level and the protein level in CE48T cells. Functional analysis showed that when incubated with oligomeric and monomeric ephrin-A1 simultaneously, ESCC cells became significantly resistant to Photofrin-PDT. Functional analysis further suggested that transmembrane and soluble ephrin-A1 may cooperate to enhance resistance to Photofrin-PDT in ESCC cells.

The miR-1224-5p/TNS4/EGFR axis inhibits tumour progression in oesophageal squamous cell carcinoma

“…In ESCC, EFNA1 and EPHA2 were upregulated, and their overexpression was correlated with short overall survival in patients 17,33,34 . EFNA1 conferred resistance to photofrin-mediated photodynamic therapy resistance in ESCC cells, and EPHA2, which was hyperphosphorylated in ESCC, promoted tumour cell proliferation, migration, invasion and epithelial-mesenchymal transition 15,16,35 . VEGFA belongs to the VEGF family and is an important cytokine for angiogenesis 36 .…”

Translational research in thoracic surgery—the National Taiwan University Hospital experience

“…Functional analysis revealed ESCC cells became obviously resistant to Photofrin-PDT when incubated with oligomeric and monomeric ephrin-A1 simultaneously. Therefore, we suggested that soluble and transmembrance ephrin-A1 might cooperate to enhance resistance to Photofrin-PDT in ESCC cells (29).…”

“…We found that both EFNA1 and TNF (tumor necrosis factor) genes were up-regulated in resistant cells and down-regulated in Photofrin-PDTtreated cells relative to untreated cells (29). EFNA1 encodes ephrin-A1, which belongs to a member of the EPH (ephrin) family, the largest subfamily of the RTKs, and plays a crucial role in tumor growth, metastasis and angiogenesis (30).…”

The AXL receptor tyrosine kinase is associated with adverse prognosis and distant metastasis in esophageal squamous cell carcinoma

“…The HER2 inhibitors included lapatinib, afatinib [38] (Tovok, provided by Boehringer Ingelheim, Taiwan), and AC480 [39] (BMS599626, synthesized by Selleckchem, S1056). After incubation for 72 hours, cell survival was determined by MTT assay as described previously [40–41]. …”

“…Protein expression was analyzed by SDS-PAGE and western blotting with specific antibodies as described previously [40–41]. The primary antibodies for protein detection were anti-AXL rabbit polyclonal antibody (pAb) (ab72069, Abcam), anti-phospho-AXL (Tyr702, D12B2) rabbit monoclonal antibody (mAb) (#5724, Cell Signaling Technology), anti-HER2 rabbit antibody (#2242, Cell signaling), anti-phospho -HER2/ErbB2 (Tyr1221/1222, 6B12) pAb (#2243, Cell Signaling Technology), anti-Actin mAb (clone C4, Millipore), anti-ERK 1 (K-23) (Santa Cruz), anti-phospho-p44/42 Erk1/2 (Thr202/Tyr204) mAb (#4370, Cell Signaling Technology), anti-Akt antibody (#9272, Cell Signaling Technology), anti-phospho-Akt (Ser473) (#9271, Cell Signaling Technology), and anti-α-Tubulin (DM1A, Abcam).…”