Hexokinase II-Derived Cell-Penetrating Peptide Mediates Delivery of MicroRNA Mimic for Cancer-Selective Cytotoxicity

Biochemistry. 2020 Jun 23;59(24):2259-2273. doi: 10.1021/acs.biochem.0c00141. Epub 2020 Jun 9.

Abstract

Cancer cells are often characterized by elevated levels of mitochondrion-bound hexokinase II (HKII), which facilitates their survival, proliferation, and metastasis. Here, we have designed a cancer-selective cell-penetrating peptide (CPP) by covalently coupling a short penetration-accelerating sequence (PAS) to the mitochondrial membrane-binding N-terminal 15 amino acids of HKII (pHK). PAS-pHK mediates efficient cellular uptake and cytosolic delivery of a synthetic mimic of miR-126, a tumor suppressor miRNA downregulated in many malignancies. Following uptake by breast cancer MCF-7 cells, the CPP-miRNA conjugate is distributed throughout the cytosol and shows strong colocalization with mitochondria, where PAS-pHK induces depolarization of mitochondrial membrane potential, inhibition of metabolic activities, depletion of intracellular ATP levels, release of cytochrome c, and, finally, apoptosis. Concomitantly, the miR-126 cargo synergistically enhances the anticancer effects of PAS-pHK. Importantly, the PAS-pHK-miR-126 conjugate is not toxic to noncancerous MCF-10A and HEK-93 cells. Our results demonstrate the potential of PAS-pHK-mediated delivery of miRNA mimics as a novel cancer-selective therapeutic strategy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology
  • Cell-Penetrating Peptides* / chemistry
  • Cell-Penetrating Peptides* / pharmacology
  • Drug Delivery Systems*
  • Female
  • HEK293 Cells
  • Hexokinase / chemistry*
  • Humans
  • MCF-7 Cells
  • MicroRNAs* / chemistry
  • MicroRNAs* / pharmacology
  • Neoplasm Proteins / metabolism

Substances

  • Cell-Penetrating Peptides
  • MIRN126 microRNA, human
  • MicroRNAs
  • Neoplasm Proteins
  • HK2 protein, human
  • Hexokinase