USE OF PLP WITH PEG-rMETase IN VIVO FOR ENHANCED EFFICACY
This invention relates to methods of modifying pyridoxal 5′ phosphate (PLP) dependent enzymes to extend the serum half-life of the enzyme, extend the in vivo period of methionine depletion in a host, and decrease the immunogenicity of the enzyme. A preferred PLP-dependent enzyme to be modified is a methioninase, preferably a recombinant methioninase (rMETase). The invention further relates to compositions comprising a modified PLP-dependent enzyme and methods of using the same.
1 . A method of decreasing serum methionine levels for an extended time period, comprising administering a formulation comprising methioninase coupled to polyalkene glycol to a subject in need thereof.
2 . The method of claim 1 , wherein the subject suffers from a neoplastic disease.
3 . The method of claim 2 , wherein the neoplastic disease is selected from the group consisting of breast cancer, kidney cancer, colon cancer, lung cancer, and prostate cancer.
4 . The method of claim 1 , further comprising the administration of pyridoxal 5′-phosphate (PLP) to the subject.
5 . The method of claim 4 , wherein the PLP is administered with the methioninase formulation.
6 . The method of claim 4 , wherein the PLP is administered separately from the methioninase formulation.
7 . The method of claim 1 , wherein the serum methionine levels are below 5 μM.
8 . The method of claim 1 , wherein the formulation is administered to the subject at least one time.
9 . The method of claim 1 , wherein the formulation is administered intravenously.
10 . The method of claim 1 , wherein the polyalkene glycol is polyethylene glycol.
11 . The method of claim 10 , wherein the polyethylene glycol is methoxypolyethylene glycol succinimidyl glutarate-5000 (MEGC-PEG-5000).
12 . The method of claim 10 , wherein the molar ratio of polyalkene glycol to methioninase is approximately 30:1.
13 . The method of claim 10 , wherein the molar ratio of polyalkene glycol to methioninase is approximately 60:1.
14 . The method of claim 10 , wherein the molar ratio of polyalkene glycol to methioninase is approximately 120:1.
15 . The method of claim 1 , wherein the methioninase is recombinantly produced.
16 . The method of claim 1 , wherein the methioninase is L -methionine α-deamino-γ-mercaptomethane lyase.
17 . A method of increasing the serum half-life of a methioninase by coupling the methioninase to a polyalkene glycol.
18 . The method of claim 17 , wherein the half-life of recombinant methioninase is adjusted by altering the amount of polyalkene glycol that is coupled to the methioninase.
19 . The method of claim 18 , wherein the molar ratio of polyalkene glycol to methioninase is approximately 30:1.
20 . The method of claim 18 , wherein the molar ratio of polyalkene glycol to methioninase is approximately 60:1.
21 . The method of claim 18 , wherein the molar ratio of polyalkene glycol to methioninase is approximately 120:1.
22 . The method of claim 17 , wherein the methioninase is recombinantly produced.
23 . The method of claim 17 , wherein the methioninase is L -methionine α-deamino-γ-mercaptomethane lyase.
24 . A method of sensitizing a tumor cell comprising:
administering to a subject a methioninase coupled to polyalkene glycol.
25 . The method of claim 24 , further comprising the administration of pyridoxal 5′-phosphate (PLP).
26 . The method of claim 25 , further comprising administering a chemotherapeutic agent.
27 . The method of claim 26 , wherein the chemotherapeutic agent is selected from the group consisting of carboplatin, cisplatin, cyclophosphamide, doxorubicin, daunorubicin, epirubicin, mitomycin C, mitoxantrone, 5-fluorouracil (5-FU), gemcitabine, methotrexate, camptothecin, irinotecan, topotecan, bleomycin, docetaxel, doxorubicin, etoposide, paclitaxel, vinblastine, vincristine, vindesine, vinorelbine, genistein, trastuzumab, ZD1839; cytotoxic agents; apoptosis-inducing agents, cell cycle control inhibitors, verapamil, and cyclosporin A.