Long non-coding RNA triplex-dependent regulation of melanoma gene networks

Shah et al., NAR Genomics and Bioinformatics, 2026, asked how the long non-coding RNA SLNCR drives melanoma. Earlier work from the same group had SLNCR acting through transcription factors. Here the question was whether SLNCR instead reaches DNA directly, by folding four short purine-rich stretches into triple helices at gene promoters, and whether shutting those contacts changes what a melanoma cell does. The four regions were mapped by prediction and by mining RNA to DNA contact data, then confirmed one by one in mobility shift assays and by proton nuclear magnetic resonance.

The functional test used AUMblock oligos from AUM BioTech, one against each of the four triplex-forming regions plus a scramble control, in A375 human melanoma cells. The oligos blocked triple-helix formation completely at a one to one ratio with their region, while the scramble oligo left the shift untouched. That shift assay covers regions 1, 3 and 4, which are the three the Figure 6A legend names. In matrigel invasion assays all four were used, and the oligos against regions 2 and 4, alone or combined, gave a 2-fold reduction in invasion against the scramble oligo. The oligos against regions 1 and 3 did not block invasion, which the authors report as unexpected. None of the oligos significantly changed how fast the cells grew.

The point that matters for a steric block is what did not happen: the oligos stopped the RNA reaching its DNA target without lowering the amount of SLNCR in the cell. That is the distinction between blocking a transcript and degrading it, and it is why the group reached for a blocking oligo rather than a knockdown when they wanted the rest of SLNCR left intact. One caveat sits in the paper itself. The Methods list a lipid transfection reagent for the blocking oligos, while the Results describe incubating the cells with them, and the paper does not say which is right.