Related Experiment Video
Updated: May 10, 2026
A Combined 3D Tissue Engineered In Vitro/In Silico Lung Tumor Model for Predicting Drug Effectiveness in Specific Mutational Backgrounds
Published on: April 6, 2016
Antitumor and modeling studies of a penetratin-peptide that targets E2F-1 in small cell lung cancer
Xiaoqi Xie1, John E Kerrigan, Tamara Minko
1Department of Pharmacology and Medicine, Rutgers Cancer Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ USA.
Abstract:
E2F-1, a key transcription factor necessary for cell growth, DNA repair, and differentiation, is an attractive target for development of anticancer drugs in tumors that are E2F "oncogene addicted". We identified a peptide isolated from phage clones that bound tightly to the E2F-1 promoter consensus sequence. The peptide was coupled to penetratin to enhance cellular uptake. Modeling of the penetratin-peptide (PEP) binding to the DNA E2F-1 promoter demonstrated favorable interactions that also involved the participation of most of the penetratin sequence. The penetratin-peptide (PEP) demonstrated potent in vitro cytotoxic effects against a range of cancer cell lines, particularly against Burkitt lymphoma cells and small cell lung cancer (SCLC) cells. Further studies in the H-69 SCLC cell line showed that the PEP inhibited transcription of E2F-1 and also several important E2F-regulated enzymes involved in DNA synthesis, namely, thymidylate synthase, thymidine kinase, and ribonucleotide reductase. As the PEP was found to be relatively unstable in serum, it was encapsulated in PEGylated liposomes for in vivo studies. Treatment of mice bearing the human small cell lung carcinoma H-69 with the PEP encapsulated in PEGylated liposomes (PL-PEP) caused tumor regression without significant toxicity. The liposome encapsulated PEP has promise as an antitumor agent, alone or in combination with inhibitors of DNA synthesis.
Insights
A novel peptide targeting the E2F-1 promoter shows potent anticancer activity against various cell lines, including small cell lung cancer. Encapsulated in liposomes, this peptide effectively reduced tumors in vivo with minimal toxicity.
Area of Science:
- Molecular Biology
- Cancer Research
- Drug Development
Background:
- E2F-1 is a crucial transcription factor for cell growth and differentiation.
- E2F-1 is a promising target for anticancer drug development in E2F-dependent tumors.
Purpose of the Study:
- To identify and develop a peptide-based therapeutic targeting the E2F-1 promoter.
- To evaluate the efficacy and safety of the developed peptide in preclinical cancer models.
Main Methods:
- Phage display was used to identify a peptide binding to the E2F-1 promoter.
- Peptide was conjugated with penetratin for enhanced cellular uptake.
- In vitro cytotoxicity assays and in vivo tumor models were employed.
- PEGylated liposomes were used for peptide encapsulation and in vivo delivery.
Main Results:
- The penetratin-peptide (PEP) exhibited potent in vitro cytotoxicity against multiple cancer cell lines, notably Burkitt lymphoma and small cell lung cancer (SCLC).
- PEP inhibited E2F-1 transcription and key DNA synthesis enzymes in SCLC cells.
- Liposome-encapsulated PEP (PL-PEP) demonstrated significant tumor regression in mice bearing human SCLC xenografts with no observed toxicity.
Conclusions:
- The PEP, particularly when encapsulated in PEGylated liposomes, is a promising anticancer agent.
- PL-PEP shows potential for treating E2F-1-driven cancers, either as a standalone therapy or in combination with other agents.
