Gene silencing is a process that reduces or eliminates the expression of a gene. This can be achieved through various methods, including RNA interference (RNAi) and antisense oligonucleotides (ASOs). In RNAi, small interfering RNAs (siRNAs) or microRNAs (miRNAs) bind to target mRNA molecules, leading to their degradation and preventing protein production. ASOs are short DNA or RNA molecules that bind to mRNA and block translation or promote degradation.

In cancer treatment, gene silencing targets specific genes responsible for tumor growth and survival. By silencing oncogenes (genes that promote cancer) or genes involved in angiogenesis (formation of new blood vessels), proliferation, and metastasis, it is possible to inhibit cancer progression. For example, siRNAs can be designed to target and silence the mRNA of oncogenes like KRAS or BCL-2, which are often overexpressed in various cancers.

Challenges in gene silencing for cancer treatment include delivery, specificity, and off-target effects. Efficiently delivering siRNAs or ASOs to cancer cells without degradation is difficult, often requiring advanced delivery systems like nanoparticles. Ensuring specificity to avoid silencing unintended genes and minimizing immune responses are also significant hurdles. Additionally, off-target effects and potential toxicity can lead to adverse reactions, complicating treatment safety and efficacy.