LINE-1-encoded reverse Transcriptase as a target in cancer therapy.

Area of Science:

• Genetics
• Molecular Biology
• Oncology

Background:

• LINE-1 elements comprise 17% of the human genome.
• LINE-1 elements encode two open reading frames (ORF1 and ORF2).
• ORF2 encodes a reverse transcriptase (RT) enzyme, crucial for LINE-1 activity.

Purpose of the Study:

• To investigate the role of LINE-1 encoded RT in cancer development.
• To evaluate the therapeutic potential of RT inhibitors in cancer treatment.

Main Methods:

• Analysis of LINE-1 element expression in human cancers and pre-neoplastic lesions.
• In vitro and in vivo experimental studies on RT inhibition.
• Phase II clinical trial in metastatic hormone-resistant prostate cancer patients.

Main Results:

• LINE-1 elements and their proteins (ORF-1p, ORF-2p) are detected in human cancers.
• RT expression is observed early in pre-neoplastic lesions.
• RT inhibition reduced cancer cell proliferation, promoted differentiation, and antagonized tumor progression in preclinical models.
• RT inhibitors demonstrated anticancer efficacy in a Phase II trial for prostate cancer.

Conclusions:

• LINE-1 encoded RT is a potential cause of cancer onset.
• RT inhibitors represent a novel, non-cytotoxic therapeutic strategy for various cancers.
• RT inhibitors may be effective in differentiation therapy for cancer treatment.