Related Experiment Video
Updated: Feb 4, 2026
Profiling of Estrogen-regulated MicroRNAs in Breast Cancer Cells
Published on: February 21, 2014
p21Waf1/Cip1: its paradoxical effect in the regulation of breast cancer
Samir F Zohny1,2, Abdulrahman L Al-Malki3, Mazin A Zamzami3
1Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Kingdom of Saudi Arabia. sfmz@hotmail.com.
Abstract:
p21Waf1/Cip1, the cyclin-dependent kinase (CDK) inhibitor belonging to the KIP/CIP family, was initially regarded as a tumor suppressor protein because it was recognized as the chief mediator of p53-dependent cell cycle arrest elicited by DNA damage. Conversely, it has been proposed that p21Waf1/Cip1 may also function as an oncogene because it can inhibit apoptosis. Thus, p21Waf1/Cip1 is regarded as a protein with a dual behavior, as its expression might cause potential benefits or dangerous effects in breast cancer. Consequently, careful planning is required in targeting p21Waf1/Cip1 expression for therapy of breast cancer patients. This review illustrates the discovery and mechanisms of induction of p21Waf1/Cip1. Then, we focus on elucidating the paradoxical effect of p21Waf1/Cip1 expression on human breast carcinogenesis and explaining how the subcellular localization (nuclear or cytoplasmic) of p21Waf1/Cip1 has an impact on both determining its fate as either cell-growth inhibitor or antiapoptotic molecule and, its effect on clinicopathological factors and prognosis of breast cancer patients. Moreover, we explore how the pattern of the p21Waf1/Cip1 could affect the responsiveness of human breast cancer to chemotherapy. Furthermore, the pharmacological approaches to target p21Waf1/Cip1 expression for therapy of breast cancer are clarified.
Insights
p21 (cyclin-dependent kinase inhibitor) has a dual role in breast cancer, acting as both a tumor suppressor and oncogene. Understanding its localization is key for effective therapeutic targeting.
Area of Science:
- Molecular Biology
- Oncology
- Biochemistry
Background:
- p21Waf1/Cip1, a cyclin-dependent kinase (CDK) inhibitor, is known for mediating p53-dependent cell cycle arrest.
- Its role in inhibiting apoptosis suggests potential oncogenic activity, presenting a dual behavior in cancer.
Purpose of the Study:
- To review the discovery, induction, and paradoxical effects of p21Waf1/Cip1 in human breast cancer.
- To elucidate the impact of p21Waf1/Cip1 subcellular localization on its function and patient prognosis.
- To explore p21Waf1/Cip1's influence on chemotherapy response and discuss therapeutic targeting strategies.
Main Methods:
- Literature review focusing on p21Waf1/Cip1 discovery and mechanisms.
- Analysis of studies investigating p21Waf1/Cip1's dual role in breast carcinogenesis.
- Examination of research on subcellular localization, clinicopathological factors, and treatment response.
Main Results:
- p21Waf1/Cip1 exhibits context-dependent functions, acting as a tumor suppressor or oncogene.
- Subcellular localization (nuclear vs. cytoplasmic) dictates p21Waf1/Cip1's role in cell cycle arrest or apoptosis inhibition.
- p21Waf1/Cip1 expression patterns correlate with breast cancer prognosis and chemotherapy sensitivity.
Conclusions:
- p21Waf1/Cip1's dual role necessitates careful therapeutic strategies in breast cancer treatment.
- Targeting p21Waf1/Cip1 based on its localization and expression pattern may improve patient outcomes.
- Further research into pharmacological approaches targeting p21Waf1/Cip1 is crucial for advancing breast cancer therapy.
Related Concept Videos
01:46Epigenetic Regulation
02:14GTPases and their Regulation
Large G-proteins,...
02:58Regulated Protein Degradation
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
02:23Master Transcription Regulators
01:23Negative Regulator Molecules
01:45Positive Regulator Molecules