Mir-21 promoter driven targeted cancer therapy

Abstract

The invention provides a nucleic acid construct comprising a promoter sequence derived from microRNA-21 (miR-21) linked to a nucleic acid sequence encoding an anti-cancer agent, an example of which is a toxin. The constructs of the invention are particularly useful for treating tumors expressing miR-21.

1 . A nucleic acid construct comprising an miR-21 promoter sequence and at least one nucleic acid sequence encoding a cytotoxic agent, wherein the nucleic acid sequence encoding the cytotoxic agent is operably linked to the miR-21 promoter sequence. 
     
     
         2 . The construct of  claim 1 , wherein the cytotoxic agent is selected from the group consisting of a toxin, a fragment of a toxin, a drug-metabolizing enzyme, and an inducer of apoptosis. 
     
     
         3 . The construct of  claim 2 , wherein the toxin is selected from the group consisting of a bacterial toxin, a plant toxin, a fungal toxin and a combination thereof; or wherein the drug-metabolizing enzyme comprises a kinase; or wherein the inducer of apoptosis is selected from the group consisting of PUMA; BAX; BAK; Bci-XS; BAD; BIM; BIK; BID; HRK; Ad EIB; an ICE-CED3 protease; TRAIL; SARP-2; and apoptin. 
     
     
         4 . The construct of  claim 3 , wherein the bacterial toxin is selected from the group consisting of  diphtheria  toxin,  Pseudomonas  exotoxin, cholera toxin, anthrax toxin, botulinum toxin, pertussis toxin,  E. coli  enterotoxin, and shiga toxin; or wherein the plant toxin is selected from the group consisting of ricin, modeccin, abrin, volkensin and viscumin; or wherein the fungal toxin is selected from the group consisting of a sarcin, restrictocin, mitogillin, enomycin, RNase T1 and phenomycin. 
     
     
         5 . The construct of  claim 4 , wherein the  diphtheria  toxin is fragment A of  diphtheria  toxin (DT-A) and has the amino acid sequence of SEQ ID NO: 19. 
     
     
         6 . The construct of  claim 1 , comprising SEQ ID NO: 1 as the miR-21 promoter sequence, and further comprising SEQ ID NO: 18 as the nucleic acid sequence encoding a cytotoxic agent. 
     
     
         7 . The construct of  claim 1 , wherein the nucleic acid construct is substantially devoid of a nucleic acid sequence corresponding to or complementary to a form of miR-21 selected from the group consisting of: a primary transcript of miR-21 (pri-miR-21); a precursor of miR-21 (pre-miR-21); an RNA duplex of miR-21, and a mature miR-21. 
     
     
         8 . The construct of  claim 1 , comprising a sequence selected from the group consisting of SEQ ID NO: 7 and SEQ ID NO: 8. 
     
     
         9 . A vector comprising the nucleic acid construct of  claim 1 . 
     
     
         10 . The vector of  claim 9 , selected from the group consisting of SEQ ID NO: 9 and SEQ ID NO: 10. 
     
     
         11 . An isolated host cell comprising the vector of  claim 9 . 
     
     
         12 . A pharmaceutical composition comprising, as an active ingredient, the construct of  claim 1 , and at least one pharmaceutically acceptable carrier, excipient or diluent. 
     
     
         13 . A method for treating cancer in a human subject, comprising administering to a human subject in need thereof a therapeutically effective amount of the nucleic acid construct of  claim 1 , thereby treating cancer in the human subject. 
     
     
         14 . A method for inhibiting tumor progression in a human subject, comprising administering to a human subject in need thereof a therapeutically effective amount of the nucleic acid construct of  claim 1 , thereby inhibiting tumor progression in the human subject. 
     
     
         15 . A method for reducing or alleviating a symptom associated with a neoplastic disorder in a human subject, comprising administering to a human subject in need thereof a therapeutically effective amount of the nucleic acid construct of  claim 1 , thereby reducing or alleviating a symptom associated with a neoplastic disorder in the human subject. 
     
     
         16 . The method of  claim 14 , wherein said subject is afflicted with a tumor characterized by endogenous expression of miR-21 in at least a portion of the cells of the tumor. 
     
     
         17 . The method of  claim 13 , wherein said subject is afflicted with a cancer selected from the group consisting of breast cancer, colon cancer, hepatocellular carcinoma, cervical cancer, cholangiocarcinoma, endometrioid ovarian carcinoma, esophageal cancer, glioblastoma, head and neck cancer, leukemia (e.g. chronic lymphocytic leukemia), lymphoma (e.g. diffuse large B cell lymphoma, activated B cell-like lymphoma), lung cancer, multiple myeloma, pancreatic (e.g. endocrine and acinar) cancer, osteosarcoma, pituitary tumor, prostate cancer, stomach cancer, and uterine leiomyoma. 
     
     
         18 . The method of  claim 17 , wherein the cancer is selected from the group consisting of breast cancer, colon cancer and hepatocellular carcinoma. 
     
     
         19 . The method of  claim 13 , wherein the administering is carried out by a route selected from the group consisting of injection, infusion and direct injection into the tumor. 
     
     
         20 . A kit comprising i) one or more dosage units of the vector of  claim 9 ; and ii) instructions for administering said nucleic acid construct to a subject in need thereof.