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Updated: Jul 10, 2026
Evaluating the Effectiveness of Cancer Drug Sensitization In Vitro and In Vivo
Published on: February 6, 2015
Novel approaches for chemosensitization of breast cancer cells: the E1A story
Yong Liao1, Dihua Yu, Mien-Chie Hung
1Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
Abstract:
The adenoviral E1A-mediated sensitization to a variety of anti-cancer drug-induced apoptosis is a well-established phenomenon on different types of cell systems. However, the mechanisms underlying E1A-mediated chemosensitization are still not fully understood. Recent studies demonstrate that E1A-mediated sensitization to drug-induced apoptosis can occur via multiple pathways; some of which depend on the expression of functional p53 and/or p19ARF proteins, while some are not. In human breast cancer cells with Her-2/neu overexpression, which usually are more resistance to anti-cancer drugs than cells without Her-2/ neu overexpression, may be sensitized through E1A-mediated downregulation of Her-2/neu. Alternatively, E1A can induce sensitization to anticancer drugs in cancer cells or normal diploid fibroblast cells through upregulating the expression of caspase proenzymes, or downregulating the activity of a critical survival factor Akt and/or upregulating the activities of a pro-apoptotic kinase p38 and a protein phosphatase PP2A, etc. This review summarizes these progresses and proposes a plausible feed-forward model for E1A-mediated chemosensitization in human breast cancer cells.
Insights
Adenoviral E1A protein sensitizes cancer cells to chemotherapy through various pathways, including targeting Her-2/neu in breast cancer. Understanding these mechanisms aids in developing more effective anti-cancer drug strategies.
Area of Science:
- Molecular Biology
- Oncology
- Virology
Background:
- Adenoviral E1A protein is known to sensitize various cell systems to anti-cancer drugs.
- The precise mechanisms of E1A-mediated chemosensitization remain incompletely understood.
- Chemosensitization can be dependent or independent of p53 and p19ARF protein expression.
Purpose of the Study:
- To review and summarize the current understanding of E1A-mediated chemosensitization mechanisms.
- To explore E1A's role in sensitizing human breast cancer cells, particularly those overexpressing Her-2/neu.
- To propose a feed-forward model for E1A-mediated chemosensitization in breast cancer.
Main Methods:
- Literature review of studies investigating adenoviral E1A and chemosensitization.
- Analysis of pathways involving p53, p19ARF, Her-2/neu, caspases, Akt, p38, and PP2A.
- Synthesis of findings to propose a mechanistic model.
Main Results:
- E1A-mediated chemosensitization involves multiple pathways, some p53/p19ARF-dependent, others not.
- In Her-2/neu overexpressing breast cancer cells, E1A may sensitize by downregulating Her-2/neu.
- E1A can also sensitize by modulating caspase proenzymes, Akt survival factor, pro-apoptotic kinase p38, and phosphatase PP2A.
Conclusions:
- E1A-mediated chemosensitization is a complex process involving diverse molecular pathways.
- E1A offers a potential strategy to overcome drug resistance in cancers like Her-2/neu-positive breast cancer.
- A feed-forward model is proposed to explain E1A's role in enhancing anti-cancer drug efficacy in breast cancer.
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