Some years ago Hiroaki Kawasaki and Kazunari Taira published an article called "Induction of DNA methylation and gene silencing by short interfering RNAs in human cells" in Nature:
In plants, dsRNAs targeted to CpG islands within a promoter can also induce RNA-directed DNA methylation3, 4, 5, 6, 7, 8; however, it remains unclear whether gene silencing mediated by DNA methylation can be induced by dsRNAs in mammalian cells. Here, we demonstrate that short interfering RNAs (siRNAs; 21–25-nucleotide RNA molecules) induce DNA methylation and histone H3 methylation in human cells.
This paper seemed to show that siRNA can also induce long-term silencing of genes by DNA methylation in mammalian cells, which hasn't previously been observed. Unfortunately, the paper was retracted later, calling the results into question.
I found the paper very exciting at the time, as it suggested the possibility to perform gene therapy, to silence specficic genes, just by using RNA interference.
What is the current scientific consensus here, is there any convincing evidence that siRNA-induced DNA methylation is possible in mammalian cells? Was anyone able to replicate the results from Kawasaki and Taira?