Peptide-conjugated antisense oligonucleotides for targeted inhibition of a transcriptional regulator in vivo

Abstract

Transcription factors are important targets for the treatment of a variety of malignancies but are extremely difficult to inhibit, as they are located in the cell's nucleus and act mainly by protein-DNA and protein-protein interactions. The transcriptional regulators Id1 and Id3 are attractive targets for cancer therapy as they are required for tumor invasiveness, metastasis and angiogenesis. We report here the development of an antitumor agent that downregulates Id1 effectively in tumor endothelial cells in vivo. Efficient delivery and substantial reduction of Id1 protein levels in the tumor endothelium were effected by fusing an antisense molecule to a peptide known to home specifically to tumor neovessels. In two different tumor models, systemic delivery of this drug led to enhanced hemorrhage, hypoxia and inhibition of primary tumor growth and metastasis, similar to what is observed in Id1 knockout mice. Combination with the Hsp90 inhibitor 17-(allylamino)-17-demethoxygeldanamycin yielded virtually complete growth suppression of aggressive breast tumors.

Id1 Expression in Endothelial Cells of the Colon Is Required for Normal Response to Injury

“…42 The current findings are consistent with those from prior studies that have demonstrated that a loss of Id1 can lead to structural and functional vascular abnormalities in tumorbearing mice. 19,32,43 However, the present study could not distinguish whether the observed vascular abnormalities are a consequence or a cause of the more severe colitis. Nonetheless, our data suggest that the depletion of ID1 in the endothelium contributes to hypoxia, which can exacerbate inflammation.…”

Id1 Is Down-Regulated by Hepatocyte Growth Factor via ERK-Dependent and ERK-Independent Signaling Pathways, Leading to Increased Expression of p16INK4a in Hepatoma Cells

“…These results indicate the importance of Id1 to the regulation of cell proliferation and suggest that the levels of Id1 are partly responsible for the difference in the effect of HGF on cell proliferation. Furthermore, recent reports showed the expression of Id1 to be related to the serum-independent proliferation of cancer cells (62), invasive behavior, and metastasis of tumors (29,31,33,35), suggesting that Id1 expression is involved in not only the regulation of cell proliferation in vitro but also carcinogenesis and malignant cell behavior in vivo. Therefore, our results showing the rapid down-regulation of Id1 induced by HGF and the signaling pathways responsible for the down-regulation are expected to provide a molecular basis for cancer therapy.…”

“…The expression of Id1 is increased in proliferating cells and decreased by the induction of cell differentiation, and ectopic expression of Id1 represses the differentiation of some kinds of cells (26)(27)(28), suggesting that Id1 is a key regulator for the proliferation and differentiation of cells. Id1 is also considered a target in cancer therapy (29)(30)(31), because it is expressed in a wide variety of primary human tumors, such as endothelial, breast, prostate, and cervical cancers, and squamous cell carcinoma (32)(33)(34)(35)(36), and its expression is involved in malignant cell behavior (36). Although accumulating evidence indicates important biological effects of Id1, signaling pathways and signaling molecules responsible for the expression of Id1 are not well defined.…”

Peptide antisense nanoparticles

“…However, molecular methods of preparing these materials are relatively inefficient, limit sequence diversity because of incompatible chemistries, require orthogonal protecting groups on nucleosides and amino acids (44), and can generate undesired side products (45). Thus, the synthesis and purification of heterofunctional molecules is a challenge.…”