MGMT Modifications for Gene Therapy Cell Selection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current gene therapy methods often fail to modify a significant portion of target cells, as they do not provide a sufficient selective advantage for the modified cells to proliferate and replace unmodified cells.
Innovation Solution
The disclosure provides methods and compositions that modify endogenous MGMT-encoding nucleic acids to confer resistance to O6-benzylguanine (O6BG), allowing modified cells to survive and proliferate in the presence of MGMT inhibitors and alkylating agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional gene therapy methods are used to modify target cells, then some cells are modified, but the frequency of modified cells remains low because they do not have a selective advantage to proliferate and replace unmodified cells
Solution Approach 1:
The patent applies parameter changes by modifying the MGMT protein through specific amino acid substitutions (P140K, P140L, P140M, P140I, P140V, P140F, P140H, P140Q, P140R, P140S, P140T, P140N, P140C, P140E, P140G, P140D, P140A) to alter its sensitivity parameters. These modifications change the protein's interaction parameters with O6-benzylguanine, transforming it from sensitive to resistant, thereby providing the selective advantage needed for modified cells to proliferate preferentially
Solution Approach 2:
The patent converts the harmful effect of O6-benzylguanine (which normally inhibits MGMT and kills modified cells) into a beneficial selective pressure. By introducing MGMT modifications that confer O6BG resistance, the previously harmful agent becomes a tool for selection: unmodified cells die in the presence of O6BG while modified cells survive and proliferate, thereby increasing the frequency of modified cells in the population
2Reliability
If MGMT is modified to confer resistance to O6-benzylguanine, then modified cells can survive and proliferate in the presence of MGMT inhibitors, but this requires specific amino acid mutations in the MGMT polypeptide
Solution Approach 1:
The patent establishes universality by demonstrating that multiple different amino acid substitutions at position 140 (P140K, P140L, P140M, P140I, P140V, P140F, P140H, P140Q, P140R, P140S, P140T, P140N, P140C, P140E, P140G, P140D, P140A) all confer the same functional outcome: resistance to O6-benzylguanine. This multi-functionality provides flexibility in achieving the desired resistance phenotype through various mutational pathways
Solution Approach 2:
The patent systematically explores parameter changes by testing multiple amino acid substitutions at a single critical position (position 140) in the MGMT polypeptide. Each substitution represents a parameter change that alters the protein's chemical properties and its interaction with O6-benzylguanine, thereby achieving resistance through controlled parametric variation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
By modifying MGMT-encoding nucleic acids to encode O6BG-resistant MGMT polypeptides, the methods enhance the frequency of modified cells, enabling more effective gene therapy by selectively expanding the population of modified cells.
Implementation Method 1
contacting an endogenous O(6)-methylguanine-DNA-methyltransferase (MGMT)-encoding nucleic acid of one or more cells of a mammalian subject with an editing enzyme to produce a modified MGMT-encoding nucleic acid
Implementation Method 2
the modified MGMT polypeptide is resistant to O6-benzylguanine (O6BG), where the modified MGMT polypeptide includes at least one mutation selected from L33F, L33K, L33P, L33R, L33W, L33Y, M134F, M134V, M134W, M134Y, R135G, R135K, R135L, R135T, N137D, N137F, N137P, P138K, P140E, P140F, P140H, G156I, G156P, G156V, Y158M, Y158W, S159F, S159I, S159L, S159P, S159T, S159W, S159Y, G160D, G160E, G160H, G160K, and G160P
Data Source
AI summary
The present disclosure includes MGMT modifications that cause MGMT resistance to MGMT inhibitors. The present disclosure also includes in vivo, in vitro, and ex vivo modification of MGMT-encoding nucleic acids to encode and express an MGMT variant that is resistant to MGMT inhibitors. Inhibitor-resistant MGMT modifications and modification of an MGMT-encoding nucleic can occur or be used in conjunction with a therapeutic modification, e.g., in a single cell. Expression of inhibitor-resistant MGMT can selectively protect modified cells from a selection regimen, such as a selection regimen including an MGMT inhibitor and an alkylating agent. Accordingly, in vivo, in vitro, and ex vivo modification of MGMT-encoding nucleic acids can be used in gene therapy to select for modified cells.