Photochemical Internalization of siRNA for Cancer Therapy

Abstract

In the race to design ever more effective therapy with ever more focused and controlled actions, nanomedicine and phototherapy seem to be two allies of choice. Indeed, the use of nanovectors making it possible to transport and protect genetic material is becoming increasingly important. In addition, the use of a method allowing the release of genetic material in a controlled way in space and time is also a strategy increasingly studied thanks to the use of lasers. In parallel, the use of interfering RNA and, more particularly, of small-interfering RNA (siRNA) has demonstrated significant potential for gene therapy. In this review, we focused on the design of the different nanovectors capable of transporting siRNAs and releasing them so that they can turn off the expression of deregulated genes in cancers through controlled photoexcitation with high precision. This mechanism, called photochemical internalization (PCI), corresponds to the lysosomal leakage of the cargo (siRNA in this case) after destabilization of the lysosomal membrane under light excitation.

Photochemical internalizationに基づく光依存的細胞質内RNA導入法の副作用低減

“…PCI による様々な物質のエンドソーム脱出/細胞質内導 入の研究は盛んに行われており，生命科学への応用研究 も進んでいる [3][4][5][6][7] ．ただし，PCI 作用の証明ばかりが公表 されていて，副作用を減らす努力については表に出てこ ない．しかし，光増感剤存在下での光細胞毒性は数々 のphotodynamic therapy の研究例の中で証明されており 14,15) ， (特に UV～青色領域の)光そのものの細胞毒性に ついても知られているため 16,17)…”

“…1. 緒言 各種キャリアを用いた動物細胞内へのタンパク質や核 酸などの生体分子(キャリアに対する積み荷分子)の導 入は，エンドサイトーシスを経由するケースが多く，そ の場合，キャリア/積み荷複合体がエンドソームに閉じ込 められてしまう問題がしばしば起こる 1,2) ．この問題の解 決法の 1 つとして，光増感剤と光を用いてエンドソーム にトラップされた物質をエンドソームから脱出させ細胞 質内に導入する方法(photochemical internalization：PCI 法)が知られている [3][4][5] ．PCI 法は，細胞に取り込まれ， エンドソームにトラップされた膜不透過性分子の光依存 的細胞質内送達法として開発され，核酸やタンパク質， 薬剤の細胞質内デリバリーに応用されてきた 6,7) ．この方 法は，送達したい分子のエンドサイトーシスが起こると き，光増感剤も同時にエンドソームに局在するように設 計されている．ここで，光を照射すると光増感剤により 活性酸素種(主に一重項酸素)が生成し，一重項酸素に よるエンドソーム膜の不安定化に基づいて，エンドソー ム内の分子が細胞質内に放出される 3) ． 本研究では，PCI に基づく光誘導 RNA 細胞質内導入法 (photoinduced cytosolic dispersion of RNA：PCDR 法)を用 いる 2) ．この手法は，細胞透過性ペプチドの一種である Tat と U1A RNA 結合タンパク質と光増感剤(PS)複合体 (TatU1A-PS)により，short hairpin RNA(shRNA)や pre-miRNA などの RNA を光依存的に細胞質内に導入する方 法である 8,9)…”

A Triazolium‐Anchored Self‐Immolative Linker Enables Self‐Assembly‐Driven siRNA Binding and Esterase‐Induced Release

“…[3,4] In 2018, the first-of-its-kind siRNA-based drug Patisiran was FDA-approved, followed by three other RNA interference-based therapeutics in 2019, 2020 and 2021 (Givosiran, Lumasiran, Inclisiran). [5,6] In 2020, the FDA granted an emergency use authorization of mRNA vaccines to fight the Covid-19 pandemic, [7] and further RNA-based drugs are currently in clinical trials. [8,9] The success of these RNA-based therapeutics relies largely on the development of lipid nanoparticle nanovectors such as micelleplexes [10][11][12][13] and liposomes [14][15][16][17] which protect RNAs from enzymatic degradation by nucleases, while also promoting (targeted) cell internalization.…”

“…After a bumpy road paved with hopes and failures, patients can today benefit from small interfering RNA (siRNA) drugs [1,2] and messenger RNA (mRNA) vaccines [3,4] . In 2018, the first‐of‐its‐kind siRNA‐based drug Patisiran was FDA‐approved, followed by three other RNA interference‐based therapeutics in 2019, 2020 and 2021 (Givosiran, Lumasiran, Inclisiran) [5,6] . In 2020, the FDA granted an emergency use authorization of mRNA vaccines to fight the Covid‐19 pandemic, [7] and further RNA‐based drugs are currently in clinical trials [8,9] …”

Special Issue “Nanoplatforms Based Cancers Therapy”

“…The PCI mechanism consists of favoring the transfer of material from lysosomes to cytoplasm via lysosomal escape induced by lysosomal membrane destabilization under laser excitation. The last review, [ 7 ], focused on the different nanovectors capable of transporting genetic material such as small-interfering RNA (siRNA) in order to block the expression of genes responsible for the development of cancer. Because the nanoparticles are mainly internalized via the endolysosomal pathway, and the RNA is found in the cytoplasm, the PCI mechanism is fully suitable for siRNA action, of which lysosomal escape is laser induced.…”