Episomal Reprogramming of iPSCs Without Oncogenes
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Solution Overview
Problem
Current methods for deriving induced pluripotent stem cells (iPSCs) using episomal reprogramming are inefficient and pose risks due to the use of oncogenes like c-Myc, L-Myc, and Lin28, which can lead to neoplastic effects and teratoma formation, and existing alternatives are not clinically viable due to immunogenicity and ethical concerns.
Innovation Solution
A method involving the expression of Sox-2, Klf-4, and Oct3/4 from non-integrating episomal DNA, combined with inhibition of p53 activity and culturing in a medium with Alk-5 inhibitors, histone deacetylase inhibitors, and activators of glycolysis, without the use of oncogenes like c-Myc, L-Myc, Lin28, or SV40 large T antigen, to achieve high reprogramming efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If retroviral transfection is used to deliver reprogramming molecules, then reprogramming efficiency is improved, but the risk of neoplastic effects and teratoma formation increases due to exogenous DNA integration and oncogene expression
Solution Approach 1:
The patent extracts and removes the harmful oncogenes (c-Myc, L-Myc, Lin28) from the reprogramming process while retaining the essential reprogramming factors (Oct4, Sox2, Nanog, Klf4). This is achieved by using episomal vectors that do not integrate into the genome and by suppressing p53 pathways that would otherwise prevent reprogramming without oncogenes.
Solution Approach 2:
The patent uses episomal vectors that are transient and non-integrating, effectively making them 'short-living' in the cellular context. These vectors deliver reprogramming factors temporarily and then are lost during cell division, eliminating the long-term safety risks of integrated viral DNA while maintaining reprogramming efficiency.
2Reliability
If episomal reprogramming without oncogenes is used, then safety is improved by eliminating neoplastic risks, but reprogramming efficiency decreases
Solution Approach 1:
The patent changes the cellular parameters by suppressing p53 activity and inhibiting TGF-beta signaling pathways. This creates a permissive cellular state that allows reprogramming to proceed efficiently without the need for oncogenes, effectively altering the cellular environment to favor reprogramming while maintaining safety.
Solution Approach 2:
The patent introduces intermediary molecules and pathways (p53 suppression, TGF-beta inhibition) that mediate between the requirement for reprogramming efficiency and the need for safety. These intermediaries create the necessary cellular conditions for efficient reprogramming without direct oncogene expression.
3Productivity
If oncogenes like c-Myc, L-Myc, and Lin28 are used in reprogramming, then reprogramming efficiency is improved, but the risk of cancer and teratoma formation increases
Solution Approach 1:
The patent extracts the harmful oncogenes (c-Myc, L-Myc, Lin28) from the reprogramming cocktail while retaining the essential factors needed for reprogramming. This is accomplished through episomal delivery of Oct4, Sox2, Nanog, and Klf4 combined with p53 suppression and TGF-beta pathway inhibition.
Solution Approach 2:
The patent converts the potential harm of p53-mediated cell cycle arrest into a benefit by suppressing p53 pathways. This suppression, which would normally be harmful by allowing cells with DNA damage to proliferate, is instead used to enable efficient reprogramming without oncogenes, and the safety is maintained through the non-integrating nature of episomal vectors.
Data Source
AI summary
Methods are disclosed for reprogramming a somatic cell, including an adherent cell and a cell in suspension, into an induced pluripotent stem comprising expressing exogenous Sox-2, exogenous Klf-4, exogenous Oct3/4 from DNA that has not integrated into the genome of the somatic cell, suppressing p53 activity within the somatic cell, and exposing the somatic cell to reprogramming-assistance factors comprising an exogenous Alk-5 inhibitor, an exogenous histone deacetylase inhibitor, and an exogenous activator of glycolysis. Compositions and kits for use in such methods are also disclosed as are cells made by such a method.