Modified siRNA Molecules Targeting KRAS mRNA
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Solution Overview
Problem
Current methods for modulating KRAS gene expression in cancer treatment are limited, particularly in addressing refractory cancers with KRAS mutations, where existing inhibitors fail due to acquired resistance, and there is a need for more effective and specific RNA interference strategies.
Innovation Solution
Development of polynucleic acid molecules, specifically siRNA molecules with 2' modified nucleotides and locked nucleic acid (LNA) modifications, that target KRAS gene sequences, formulated as pharmaceutical compositions for various administration routes, including nanoparticle formulations, to inhibit KRAS expression in cancer cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard siRNA molecules are used to target KRAS gene, then RNA interference effect is achieved, but the molecules suffer from rapid degradation by nucleases and low cellular uptake efficiency
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of nucleotides in the siRNA molecule. Specifically, 2'-O-methyl modifications are introduced at certain positions, and phosphorothioate linkages are used instead of standard phosphodiester bonds. These chemical parameter changes enhance nuclease resistance and improve cellular uptake while maintaining RNAi activity.
Solution Approach 2:
The patent creates a composite siRNA structure by combining different types of nucleotide modifications within a single molecule. The molecule includes unmodified nucleotides, 2'-O-methyl modified nucleotides, and phosphorothioate linkages in specific configurations. This composite approach optimizes both stability and biological activity by distributing different functional characteristics throughout the molecule.
2Reliability
If highly modified siRNA molecules are used to improve stability, then nuclease resistance increases, but the molecular complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies local quality by introducing modifications at specific positions rather than uniformly throughout the entire siRNA molecule. The 2'-O-methyl modifications are placed at designated nucleotides (e.g., positions 1-3 and 19-21), and phosphorothioate linkages are inserted at specific locations. This localized approach provides nuclease resistance where most needed while keeping the overall structure manageable.
3Productivity
If conventional KRAS inhibitors are used, then initial treatment response is achieved, but acquired resistance develops leading to treatment failure in refractory cancers
Solution Approach 1:
The patent uses siRNA molecules as intermediaries to achieve gene silencing. Instead of directly inhibiting the KRAS protein with small molecule inhibitors that face resistance issues, the siRNA mediates RNA interference at the mRNA level, preventing translation of KRAS protein. This intermediary approach bypasses the resistance mechanisms that develop against direct protein inhibitors.
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
The modified siRNA molecules effectively down-regulate KRAS mRNA levels in cancer cells, including those with refractory mutations, leading to reduced cell viability and potential therapeutic benefits in treating KRAS-associated cancers with enhanced specificity and stability.
Implementation Method 1
Gene suppression by RNA-induced gene silencing provides several levels of control: transcription inactivation, small interfering RNA (siRNA)-induced mRNA degradation, and siRNA-induced transcriptional attenuation. In some instances, RNA interference (RNAi) provides long lasting effect over multiple cell divisions.
Data Source
Figure 1
AI summary
Disclosed herein are molecules and pharmaceutical compositions that mediate RNA interference against KRAS. Also described herein include methods for treating a disease or disorder that comprises a molecule or a pharmaceutical composition that mediate RNA interference against KRAS.