Nuclease resistant oligonucleotides with cell penetrating properties

Abstract

2'-O-AECM modified oligonucleotides provide an unusual combination of remarkable properties. This includes the combination of high resistance towards enzymatic degradation and the spontaneous cellular uptake of AECM oligonucleotides.

Synthesis, binding, nuclease resistance and cellular uptake properties of 2′- O -acetalester-modified oligonucleotides containing cationic groups

“…These data are rather unexpected if we compare with reported hybridization properties of 2 0 -modified ONs containing cationic side chains which typically exhibit high binding affinity to complementary RNA. 24,34 Nevertheless with aliphatic 2 0 -alkylamine modifications such as aminoethyl, aminopropyl, aminopentyl and aminohexyl a duplex destabilization was observed with increasing number of modified nucleotides compared to unmodified duplex. 35,36 In addition, it is noteworthy that a decrease in affinity of ON 14 containing AMEBuOM sugars for RNA complement is obtained compared to simple tert-butyl side chain (ON 15).…”

“…20 In the same way, many 2 0 -O-tethered amino groups were reported to confer nuclease resistance properties and to promote cellular uptake of such cationic ON. 24 (aminoethyl)carbamoyl)methyl modified ONs demonstrated resistance to degradation in human serum and cell penetration, without any additives. 24 In this context and in extension of the prodrug-like approach with 2 0 -O-acetalester modifications, we designed ONs modified with new 2 0 -O-acetalester groups bearing positive charges, and their properties have been studied.…”

“…24 (aminoethyl)carbamoyl)methyl modified ONs demonstrated resistance to degradation in human serum and cell penetration, without any additives. 24 In this context and in extension of the prodrug-like approach with 2 0 -O-acetalester modifications, we designed ONs modified with new 2 0 -O-acetalester groups bearing positive charges, and their properties have been studied. It is noteworthy that Damha's group has been earlier interested in the synthesis of ONs containing amino acid based acetalesters particularly with lysine for its increased net positive charge.…”

“…17 Indeed, cationic or zwitterionic ONs have shown significant cell penetrating properties and stability towards hydrolytic enzymes. [18][19][20][21][22][23][24] Particularly, the guanidinium group which has the advantage of remaining protonated over a wide pH range (pK a around 12.5) has been incorporated into ONs at selected positions on the 2 0 -OH ribose, 25,26 nucleobases 19,27 or phosphate backbone. 20 In the same way, many 2 0 -O-tethered amino groups were reported to confer nuclease resistance properties and to promote cellular uptake of such cationic ON.…”

Oligonucleotides with Cationic Backbone and Their Hybridization with DNA: Interplay of Base Pairing and Electrostatic Attraction

“…These limitations andt he quest for oligonucleotides with fundamentally different properties have led to the development of positively charged nucleic acids.I nm ost cases, positive charges were introduced through am odification of the 2'-hydroxy groups (in RNA) or nucleobases leaving the phosphate diesterb ackbone unchanged. These strategies furnished zwitterionic structures, [8] but resulted in denselyc harged oligonucleotides.…”