Self-transfecting GMO-PMO chimera targeting Nanog enable gene silencing in vitro and suppresses tumor growth in 4T1 allografts in mouse

Synthesis of Self Permeable Antisense PMO Using C5-Guanidino-Functionalized Pyrimidines at the 5'-End Enables Sox2 Downregulation in Triple Negative Breast Cancer Cells

Delivery of macromolecular drugs inside cells has been a huge challenge in the field of oligonucleotide therapeutics for the past few decades. Earliest natural inspirations included the arginine rich stretch of cell permeable HIV-TAT peptide, which led to the design of several molecular transporters with varying numbers of rigid or flexible guanidinium units with different tethering groups. These transporters have been shown to efficiently deliver phosphorodiamidate morpholino oligonucleotides, which have a neutral backbone and cannot form lipoplexes. In this report, PMO based delivery agents having 3 or 4 guanidinium groups at the C5 position of the nucleobases of cytosine and uracil have been explored, which can be assimilated within the desired stretch of the antisense oligonucleotide. Guanidinium units have been connected by varying the flexibility with either a saturated (propyl) or an unsaturated (propargyl) spacer, which showed different serum dependency along with varied cytoplasmic distribution. The effect of cholesterol conjugation in the delivery agent as well as at the 5'-end of full length PMO in cellular delivery has also been studied. Finally, the efficacy of the delivery has been studied by the PMO mediated downregulation of the stemness marker Sox2 in the triple-negative breast cancer cell line MDA-MB 231. These results have validated the use of this class of delivery agents, which permit at a stretch PMO synthesis where the modified bases can also participate in Watson-Crick-Franklin base pairing for enhanced mRNA binding and protein downregulation and could solve the delivery problem of PMO.

VEGF signaling: Role in angiogenesis and beyond

Angiogenesis is a crucial process for tissue development, repair, and tumor survival. Vascular endothelial growth factor (VEGF) is a key driver secreted by cancer cells, promoting neovascularization. While VEGF's role in angiogenesis is well-documented, its influence on the other aspects in tumor microenvironemt is less discussed. This review elaborates on VEGF's impact on intercellular interactions within the tumor microenvironment, including how VEGF affects pericyte proliferation and migration and mediates interactions between tumor-associated macrophages and cancer cells, resulting in PDL-1-mediated immunosuppression and Nrf2-mediated epithelial-mesenchymal transition. The review discusses VEGF's involvement in intra-organelle crosstalk, tumor metabolism, stemness, and epithelial-mesenchymal transition. It also provides insights into current anti-VEGF therapies and their limitations in cancer treatment. Overall, this review aims to provide a thorough overview of the current state of knowledge concerning VEGF signaling and its impact, not only on angiogenesis but also on various other oncogenic processes.

Synthesis and Biophysical Properties of Triazole-Incorporated PMOs (TzPMOs): A Convergent, Click Ligation Approach

The synthesis of phosphorodiamidate morpholino oligonucleotides (PMOs) incorporating single or double triazole rings in the backbone has been achieved via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The synthetic approach implemented is fundamentally convergent, involving the ligation of a 5'-azide PMO fragment to a 3'-alkyne fragment both in solution and on solid support. To access the 3'-alkyne PMO fragment, we synthesized 3'-N-propargyl chlorophosphoramidate morpholino monomers for all four nucleobases. The resulting triazole-incorporated PMOs (TzPMOs) have exhibited comparable or improved binding affinity toward complementary deoxyribonucleic acid (DNA)/ribonucleic acid (RNA) strands compared to its regular analogues. Finally, a full-length TzPMO was designed to target the Nanog gene, demonstrating almost identical hybridization properties when compared to its regular version. Circular dichroism studies revealed a B-type helical conformation for the duplexes formed by TzPMOs.