Researchers at the Hebrew University of Jerusalem have developed a groundbreaking drug molecule capable of precisely targeting and destroying TERRA, a long non-coding RNA that enables certain cancer cells to survive and proliferate indefinitely. The innovative approach, published in Advanced Science, utilizes RIBOTAC (Ribonuclease Targeting Chimera) technology to achieve unprecedented selectivity in RNA degradation.
Novel Targeting Mechanism
The research team, led by Dr. Raphael I. Benhamou alongside colleagues Elias Khaskia and Dipak Dahatonde at Hebrew University's Faculty of Medicine, designed a small molecule RIBOTAC that specifically recognizes TERRA's unique G-quadruplex structure. This four-stranded nucleic acid configuration forms a distinct three-dimensional conformation that allows the RIBOTAC molecule to selectively dock and recruit endogenous RNase L, a cellular enzyme specializing in RNA cleavage.
"We've created a tool that acts like a guided missile for bad RNA," said Dr. Benhamou. "It can find TERRA inside cancer cells and make it disappear — without harming healthy parts of the cell."
TERRA's Role in Cancer Biology
TERRA (Telomeric Repeat-containing RNA) normally plays an essential role in maintaining chromosome integrity by protecting telomeres—the chromosome end caps that preserve genomic stability. However, aberrant TERRA activity or overexpression has been linked to cancer cell immortality, particularly in aggressive brain and bone tumors. These cancers exploit TERRA's properties to sustain continuous growth, evading the typical cellular senescence or apoptosis that would naturally curtail malignant proliferation.
Experimental Validation
Testing of the RIBOTAC molecule in cultured cancer cell lines, including HeLa cells derived from cervical carcinoma and U2OS cells representing osteosarcoma, demonstrated significant decreases in TERRA levels. More importantly, this reduction correlated with a marked slowdown in cancer cell growth, affirming the therapeutic potential of targeting RNA structures unique to cancer biology.
The findings suggest that TERRA degradation disrupts cancer cells' ability to maintain telomere stability, thus impairing their proliferation and survival. Unlike traditional gene-silencing therapies or protein-targeted drugs, this method ensures remarkable specificity by sparing other similar RNA molecules that share sequence homology but lack the unique G-quadruplex fold.
Paradigm Shift in Drug Discovery
The utilization of RIBOTAC technology reflects a profound shift in pharmaceutical targeting paradigms—from proteins, which have traditionally been the mainstay of therapeutic intervention, toward RNA molecules as critical regulators and effectors in disease. By leveraging intrinsic cellular pathways, such as RNase L-mediated cleavage, RIBOTACs offer a dynamic, tunable, and highly specific modality to selectively degrade pathogenic RNA species.
Dr. Benhamou emphasized the revolutionary implications: "This is a new era for drug discovery. Instead of focusing solely on proteins, we have opened a pathway to target RNA molecules that orchestrate cellular machinery. This opens the door to treating diseases that have long been deemed untargetable, offering hope for conditions like cancer which have historically challenged existing therapies."
Broader Therapeutic Potential
The versatility of RIBOTAC technology extends beyond oncology. Since RNA molecules mediate diverse biological processes and are implicated in numerous diseases, the molecular framework developed by the Hebrew University team is anticipated to catalyze research into RNA-targeted treatments for viral infections, neurological disorders, and genetic diseases.
While further in vivo studies and clinical trials will be necessary to establish safety, biodistribution, pharmacokinetics, and efficacy in patients, the initial proof-of-concept provides a compelling foundation for rapid development of RNA-structured-based therapeutics. This technology exemplifies the power of integrating structural biology, chemical synthesis, and molecular medicine to pioneer selective and potent interventions.
