Disulfide-Unit Conjugation Enables Ultrafast Cytosolic Internalization of Antisense DNA and siRNA.

Development of intracellular delivery methods for antisense DNA and siRNA is important. Previously reported methods using liposomes or receptor-ligands take several hours or more to deliver oligonucleotides to the cytoplasm due to their retention in endosomes. Oligonucleotides modified with low molecular weight disulfide units at a terminus reach the cytoplasm 10 minutes after administration to cultured cells. This rapid cytoplasmic internalization of disulfide-modified oligonucleotides suggests the existence of an uptake pathway other than endocytosis. Mechanistic analysis revealed that the modified oligonucleotides are efficiently internalized into the cytoplasm through disulfide exchange reactions with the thiol groups on the cellular surface. This approach solves several critical problems with the currently available methods for enhancing cellular uptake of oligonucleotides and may be an effective approach in the medicinal application of antisense DNA and siRNA.

Immunocytochemical utility of claudin-4 versus those of Ber-EP4 and MOC-31 in effusion cytology.

BACKGROUND: Recently, claudin-4 (CL4) immunocytochemistry was reported to be useful for differential diagnosis in effusion cytology. We wondered whether CL4 might be useful for "single-shot" identification of metastatic carcinoma. The purpose of this study was to evaluate the usefulness of CL4 in effusion cytology. METHODS: In total, 266 cases (169 metastatic carcinomas, eight malignant mesotheliomas, and 89 reactive mesothelial cells) were selected. Immunocytochemical examinations of cell-block sections were performed for CL4, Ber-EP4, and MOC-31. We used an arbitrary 4-tiered scale based on both staining intensity and positive-cell percentage among all target cells, and calculated a staining index score (sum of the above two scores). RESULTS: In a ROC-curve analysis, higher area-under-curve values were found for CL4 than for Ber-EP4 or MOC-31 (0.982, 0.942, and 0.926, respectively). CONCLUSIONS: Since CL4 exhibited similar or superior usefulness to Ber-EP4 and MOC-31, it could become the first choice for the above differential diagnosis in effusion cytology. Diagn. Cytopathol. 2016;44:499-504. © 2016 Wiley Periodicals, Inc.