Novel PD-L1 Targeting DNA Vaccine for Cancer Immunotherapy

Abstract

The present invention relates to an attenuated strain of Salmonella comprising at least one copy of a DNA molecule comprising an expression cassette encoding PD-L1. In particular, the present invention relates to said attenuated strain of Salmonella for use in the treatment of cancer.

1 - 16 . (canceled) 
     
     
         17 . A method of treating cancer in a cancer patient, comprising administering to the cancer patient an attenuated strain of  Salmonella  comprising at least one copy of a DNA molecule comprising a eukaryotic expression cassette encoding PD-L1 comprising an amino acid sequence of amino acids 19 to 238 as set forth in SEQ ID NO: 13 or an amino acid sequence having at least 80% sequence identity with amino acids 19 to 238 of SEQ ID NO: 13. 
     
     
         18 . The method according to  claim 17 , wherein the attenuated strain of  Salmonella  is  Salmonella typhi  Ty21a. 
     
     
         19 . The method according to  claim 17 , wherein the PD-L1 protein comprises an amino acid sequence as set forth in SEQ ID NO: 2 or SEQ ID NO: 13 or an amino acid sequence having at least 80% sequence identity with SEQ ID NO: 2 or SEQ ID NO: 13. 
     
     
         20 . The method according to  claim 19 , wherein PD-L1 is encoded by the nucleic acid sequence set forth in SEQ ID NO: 4 or SEQ ID NO: 14. 
     
     
         21 . The method according to  claim 17 , wherein the DNA molecule further comprises the kanamycin antibiotic resistance gene, the pMB1 ori and a CMV promoter, wherein the DNA molecule comprises the DNA sequence set forth in SEQ ID NO 5. 
     
     
         22 . The method according to  claim 17 , wherein the attenuated strain of  Salmonella  provides anti-cancer immunotherapy to the cancer patient. 
     
     
         23 . The method according to  claim 17 , wherein the method further comprises administering chemotherapy, radiotherapy, or biological cancer therapy. 
     
     
         24 . The method according to  claim 23 , wherein the biological cancer therapy comprises administering at least one further attenuated strain of  Salmonella  comprising at least one copy of a further DNA molecule comprising a further eukaryotic expression cassette encoding a tumor antigen and/or a tumor stroma antigen. 
     
     
         25 . The method according to  claim 24 , wherein the at least one further attenuated strain of  Salmonella  encodes a tumor antigen selected from the group consisting of Wilms' Tumor Protein (WT1), Mesothelin (MSLN), carcinoembryonic antigen (CEA), CMV pp65 and/or encodes a tumor stroma antigen selected from the group consisting of VEGFR-2 or human fibroblast activation protein (FAP). 
     
     
         26 . The method according to  claim 25 , wherein the at least one further attenuated strain of  Salmonella  encodes a tumor antigen selected from the group consisting of Wilms' Tumor Protein (WT1) having the amino acid sequence as set forth in SEQ ID NO: 6, Mesothelin (MSLN) having the amino acid sequence as set forth in SEQ ID NO 7, CEA having the amino acid sequence as set forth in SEQ ID NO 8, CMV pp65 having the amino acid sequence as set forth in SEQ ID NO 9, CMV pp65 having the amino acid sequence as set forth in SEQ ID NO 10, and CMV pp65 having the amino acid sequence as set forth in SEQ ID NO 11, and wherein the at least one further attenuated strain of  Salmonella  encodes a tumor stroma antigen selected from the group consisting of VEGFR-2 having the amino acid sequence as set forth in SEQ ID NO: 12 and human fibroblast activation protein (FAP). 
     
     
         27 . The method according to  claim 17 , wherein the attenuated strain of  Salmonella  is administered orally. 
     
     
         28 . The method according to  claim 27 , wherein the cancer is selected from lymphoma, leukemia, myeloma, lung cancer, non-small cell lung cancer (NSCLC), melanoma, renal cell cancer, ovarian cancer, glioblastoma, merkel cell carcinoma, bladder cancer, head and neck cancer, colorectal cancer, esophageal cancer, cervical cancer, gastric cancer, hepatocellular cancer, prostate cancer, breast cancer, pancreatic cancer, and thyroid cancer. 
     
     
         29 . The method according to  claim 17 , wherein a single dose of the attenuated strain of  Salmonella  comprises from about 10 5  to about 10 11  colony forming units (CFU). 
     
     
         30 . The method according to  claim 17 , further comprising assessing the patient's PD-L1 expression pattern and/or the pre-immune response against PD-L1 before and/or after the treatment with the attenuated strain of  Salmonella.    
     
     
         31 . The method according to  claim 19 , wherein the PD-L1 comprises an amino acid sequence having at least 90% sequence identity with SEQ ID NO: 2 or SEQ ID NO: 13. 
     
     
         32 . The method of  claim 24 , wherein said at least one further attenuated strain of  Salmonella  is  Salmonella typhi  Ty21a.