Dual TGF-ß and PD-1 blockade synergistically enhances MAGE-A3-specific CD8+ T cell response in esophageal squamous cell carcinoma.

PD-1 is highly expressed on tumor-infiltrated antigen-specific T cells and limit the antitumor function. Blocking of PD-1/PD-L1 signaling has shown unprecedented curative efficacies in patients with advanced cancer. However, only a limited population of patients benefited from such therapies. Our study aimed to explore biological properties, functional regulation and reversal of MAGE-A3-specific CD8+ T cells in patients with esophageal squamous cell carcinoma (ESCC). The underlying principle of deficiency and restoring MAGE-A3-specific CD8+ T cells function in tumor microenvironment (TME) was evaluated. MAGE-A3-specific CD8+ T cells could lyse HLA-A2+ /MAGE-A3+ tumor cells. Tetramer+ T cell frequency was higher in elder patients, but lower in patients with lymph node metastasis and late tumor stage (p < 0.05). CD107ahigh expression on functional T cells was an independent prognostic factor in Cox regression analysis. PD-1 was highly expressed on dysfunctional antigen-specific CD8+ T cells and tumor infiltrating T lymphocytes (p < 0.05). Myeloid-derived suppressor cells (MDSCs) derived-TGF-ß mediated PD-1high expression on CD8+ T cells, which led to be resistance to PD-1/PD-L1 blockade in TME. Dual PD-1/PD-L1 and TGF-ß signaling pathway blockades synergistically restored the function and antitumor ability of antigen-specific CD8+ T cells in vitro/vivo assay. The presence of functional MAGE-A3-specific CD8+ T cells had an independent prognostic impact on survival of patients with ESCC. Furthermore, MDSCs-derived TGF-ß increased PD-1 expression on T cells and decreased the sensitivity to PD-1/PD-L1 blockade. Combining T cell-based therapy with dual PD-1/PD-L1 and TGF-ß signaling pathway blockade could be considered a promising strategy for cancer treatment.

Augmenting the Effectiveness of CAR-T Cells by Enhanced Self-Delivery of PD-1-Neutralizing scFv.

Chimeric antigen receptor T (CAR-T) cell therapy is not satisfying in solid tumors. PD-1-mediated suppression greatly hinders CAR-T cells in the microenvironment. It has been shown that PD-1 blockade improves the effectiveness of CAR-T cells. Herein, we designed CAR-T cells than could secret α-PD-1 scFv by themselves. To obtain optimal secretions of scFv, we screened several signal peptides. And the segment from human increased the extracellular production of PD-1-neutralizing proteins. The secreted neutralizing scFv efficiently blocked PD-1 and enhanced T cell activation when PD-L1 was present. Further analysis showed that CAR-T cells themselves could secret α-PD-1 scFv with bioactivity. In contrast to the prototype, the scFv-producing CAR-T cells demonstrated decreased PD-1 but increases expansion and toxicity against solid tumor cells. In the subcutaneous and orthotopic xenograft models, the self-delivered α-PD-1 scFv increased CAR-T cell functionalities and tumor-suppressions. Our work suggested that engineering T cells to co-express antigen-responsive receptors and checkpoint inhibitors is effective to optimize CAR-T cell therapy for solid tumors.

Musashi1, a potential prognostic marker in esophageal squamous cell carcinoma.

Esophageal cancer ranks as the sixth leading cause of cancer-related deaths worldwide. Cancer stemness is mainly considered to be the key factor for cancer recurrence particularly in esophageal cancer. It is important to identify cancer stem cell markers as targets in future therapies. The present study aimed to investigate the expression of putative cancer stem cell-related marker musashi1 (Msi1) and assess the correlation with clinicopathologcal status of esophageal squamous cell carcinoma (ESCC) cases. We then clarified the role of Msi1 in esophageal cancer cells during proliferation, apoptosis, sphere formation and migration. Finally, we investigated the relationship of Msi1 with the prognosis of ESCC patients. ESCC tissue samples from 93 patients and 20 paired histologically normal tissues were procured for immunohistochemical analysis. We analyzed the characteristics of Msi1, using sphere formation and anchorage independent growth. Moreover, using flow cytometry and Cell Counting Kit-8 (CCK-8) assay, we investigated the role of Msi1 in cancer cell proliferation and apoptosis. Furthermore, we clarified the role of Msi1 in the process of sphere formation and migration of ESCC cells through knockdown of Msi1 expression by siRNA in ESCC cell lines. The results revealed that there was a higher expression of Msi1 in ESCC specimens compared with normal tissues. In addition, Msi1 expression was significantly associated with clinical stage and lymph node metastasis. Most importantly, the increased immunocytochemical staining of Msi1 in spheroid cells revealed the stemness characteristics of Msi1 in ESCC. In addition, we found that silencing of Msi1 decreased cell proliferation, migration and induced apoptosis in TE-7 and KYSE70 cells. Furthermore, downregulation of Msi1 attenuated the sphere formation ability of ESCC cells. Patients with higher expression of Msi1 had a shorter survival. In conclusion, Msi1 acts as a stemness-associated gene in esophageal cancer cell lines and could serve as a prognostic marker in patients with ESCC.