ZIF-C as non-viral delivery system for CRISPR/Cas9 mediated hTERT knockdown in cancer cells

Telomerase, a ribonucleoprotein coded by the hTERT gene, plays an important role in cellular immortalization and carcinogenesis. hTERT is a suitable target for cancer therapeutics as its activity is highly upregulated in 85-90% of cancer cells but absent in normal somatic cells. Here, we target the hTERT gene at the DNA level by applying the Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9 technology encapsulated in a recently discovered Metal-Organic Framework (MOF). We show that the MOF subtype ‘ZIF-C’ can efficiently load the hTERT targeting CRISPR system (CrhTERT@ZIF-C) and protect it from enzymatic degradation. The CrhTERT@ZIF-C is endocytosed by cancer cells and successfully disrupts the hTERT gene. The resultant inhibition of hTERT decreases cellular proliferation and causes apoptotic cancer cell death. Furthermore, hTERT knockdown shows a significant reduction in tumor metastasis and alters protein expression. Thus, our results conclusively establish ZIF-C based targeting of hTERT as a highly promising and novel approach for gene therapy in cancer.