Delaminated layered double hydroxide delivers DNA molecules as sandwich nanostructure into cells via a non-endocytic pathway

Layered double hydroxides （LDHs） are effective molecular carriers in cytological research, gene therapy, and transgenic applications. Herein, we investigated the internalization behavior of the LDH-DNA biocon- jugates via a microscopic approach and analyzed the internalization pathway by dissipative particle dynamics （DPD） simulations. We experimentally found that LDH can efficiently carry DNA into the nucleus of cell in BY-2 suspension cells. Furthermore, atomic force microscopy and X-ray diffraction anal- ysis demonstrated that the LDH-DNA bioconjugates mainly exist as a DNA-LDH-DNA sandwich complex, while the LDH-DNA-LDH sandwich complex and DNA-LDH complex cannot be excluded. The DPD simu- lations further indicated that only the DNA-LDH-DNA sandwich structure could penetrate the plasma membrane （PM）, while PM is impermeable to the LDH-DNA-LDH sandwich complex and the DNA-LDH complex. This work provides novel perspective for understanding the membrane penetration mechanism of LDH nano-sheets and new insights into the design of novel molecular delivery systems.

Co-occurrence of germline pathogenic variants for different hereditary cancer syndromes in patients with Lynch syndrome

Background:Lynch syndrome(LS)is a hereditary condition characterized by a high risk of colorectal cancer,endometrial cancer,and other neoplasia associated with germline alterations in DNA mismatch repair genes.The classical genetic diagnostic strategy for LS consists of the Sanger sequencing of genes associated with the suspected syndrome.Next-generation sequencing(NGS)enables the simultaneous sequencing of a large number of hereditary cancer genes.Here,we aimed to study whether other germline pathogenic variants of hereditary cancer genes are present in patients with LS.Methods:A cohort of 84 probands with a previous genetic diagnosis of LS by Sanger sequencing was reanalyzed using NGS via a commercial panel of 94 hereditary cancer genes by hybrid capture.The American College of Medical Genetics and Genomics criteria were used to classify the clinical significance of the variants.The findings of NGS were confirmed by Sanger sequencing.When possible,genetic analyses of the new findings in the proband’s relativeswere also performed by Sanger sequencing.Results:We identified five families(6%),out of 84,with at least two germline pathogenic variants conferring to high or moderate risk in different dominant cancer-predisposing genes:[MLH1-BRCA2-NBN],[MLH1-BRCA1],[MSH2-ATM],[MSH6-NF1],and[MLH1-FANCA].Interestingly,only one out of these five families exhibited a clinical phenotype associated with the new pathogenic variants.The family with three pathogenic variants of the[MLH1-BRCA2-NBN]genes showed a high aggregation of tumors associated with LS and breast and ovarian cancer syndrome.Conclusions:Our results showed that the co-occurrence of more than one pathogenic variant in cancer-predisposing genes was remarkable among cases of LS.Inmost cases,no clinicial manifestations were associated with the secondary pathogenic variants.Further studies are needed to confirm these findings and elucidate their clinical impact.Reanalysis of LS families should be considered only in families with mixed clinical phenotypes.