PTTG1 Enhances Oncolytic Adenovirus 5 Entry into Pancreatic Adenocarcinoma Cells by Increasing CXADR Expression.

Pituitary tumor-transforming gene 1 (PTTG1) is overexpressed in various types of tumors and functions as an oncogene; it could also be a potential target in tumor therapy. Meanwhile, the high mortality of pancreatic adenocarcinoma (PAAD) largely depends on the limited effectiveness of therapy. Based on the promising potential of PTTG1 in cancer treatment, we explored the influence of PTTG1 on the treatment of PAAD in this study. The Cancer Genome Atlas Program (TCGA) data showed that higher expression of PTTG1 was associated with higher clinical stages and worse prognosis of pancreatic cancer. In addition, the CCK-8 assay showed that the IC50 of gemcitabine and 5-fluorouracil (5-FU) was increased in BxPC-3-PTTG1high and MIA PaCa-2-PTTG1high cells. The TIDE algorithm indicated that the immune checkpoint blockades' (ICBs) efficiency is poor in the PTTG1 high group. Furthermore, we found that the efficiency of OAd5 was enhanced in BxPC-3-PTTG1high and MIA PaCa-2-PTTG1high cells and poor in BxPC-3-PTTG1low and MIA PaCa-2-PTTG1low cells. We used the OAd5 expressing GFP for transduction. As a result, the fluorescence intensity was enhanced in BxPC-3-PTTG1high and MIA PaCa-2-PTTG1high cells and decreased in BxPC-3-PTTG1low and MIA PaCa-2-PTTG1low cells 24 h after OAd5 transduction. The fluorescence intensity indicated that PTTG1 increased OAd5 entry. The flow cytometry assay showed that OAd5 receptor CXADR expression was enhanced by PTTG1. PTTG1 failed to further enhance OAd5 transduction in the case of CXADR knockdown. In summary, PTTG1 enhanced OAd5 transduction into pancreatic cancer cells by increasing CXADR expression on the cell surface.