Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the United States and Europe. Recent progress in our understanding of CLL biology and the development of new therapy such as fludarabine-based regimens has led to improvements of the therapeutic outcomes. However, many CLL patients, particularly those with loss of p53 due to chromosome 17p deletion or p53 mutations, are highly resistant to the current therapeutic agents and have very poor prognosis. The underlying mechanisms responsible for the poor therapeutic responses of CLL cells lacking p53 are poorly understood, and effective therapies to treat this population of CLL patients remain to be developed. The current research proposal aims to answer some of the key questions in this area, and to develop novel therapeutic strategies for treating refractory CLL. Our previous studies showed that CLL cells from patients in advanced disease stages exhibit mitochondrial DNA (mtDNA) mutations and dysfunction, elevated generation of reactive oxygen species (ROS), and decreased sensitivity to fludarabine. Furthermore, p53 plays an important role in maintaining mitochondrial genetic integrity through its interaction with mitochondrial pol 3. Importantly, we observed that cancer cells with increased ROS are highly sensitive to further ROS stress induced by a natural compound 2-phenethyl isothiocyanate (PEITC). Our preliminary studies have revealed promising activity of PEITC against refractory CLL cells, leading to major efforts to develop this compound for clinical treatment of CLL. Based on these observations, we hypothesize that CLL cells with p53 deletion are prone to develop mitochondrial mutations and dysfunction leading to a decrease in apoptotic response and resistance to conventional therapeutic agents, but remain sensitive to PEITC which kills drug-resistant CLL cells through ROS-mediated mechanism. This research project will investigate 3 specific aims. (1) We will use primary leukemia cells from CLL patients with different p53 status compare their mtDNA mutation rates, and use a novel CLL culture system to test the role p53 deletion in mitochondrial mutations and attenuation of drug apoptotic response to therapeutic agents. (2) Investigate the ability and mechanisms of PEITC and other ROS-stressing agents to effectively kill primary CLL cells that lack p53 and are resistant to conventional drugs. (3) Test the in vivo therapeutic activity of PEITC, alone or in combination with other drugs, using mouse xenograft models bearing human CLL cells with or without p53 to evaluate if PEITC and other ROS-stressing agents can induce CLL remission and improve survival. This study will reveal the novel roles of p53 in affecting mitochondrial genetic stability and function and drug sensitivity in CLL cells, and provide new strategies to effectively kill refractory CLL cells through ROS-mediated mechanism. Because PEITC is a natural compound found in vegetables with low toxicity to normal cells, its applications for clinical treatment of refractory CLL is feasible and highly significant.
Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the western world and causes a significant health burden both in morbidity and mortality. CLL cells with p53 loss due to chromosome 17p deletion or p53 gene mutation are resistant to current therapeutic agents and these patients have poor clinical outcomes. The main objectives of this research project are to investigate the underlying mechanisms by which the loss p53 leads to mitochondrial dysfunction and drug resistance, and to test novel agents and therapeutic strategies to effectively kill the drug-resistant CLL cells lacking p53. This study will reveal the important role of p53 in affecting mitochondrial function and drug sensitivity in CLL cells, and will identify new therapeutic agents for effective treatment of CLL patients who are refractory to conventional drugs. This research will have directly implications in clinical treatment of this most common adult leukemia.
|Yuan, Shuqiang; Lu, Yunxin; Yang, Jing et al. (2015) Metabolic activation of mitochondria in glioma stem cells promotes cancer development through a reactive oxygen species-mediated mechanism. Stem Cell Res Ther 6:198|
|Pelicano, HÃ©lÃ¨ne; Zhang, Wan; Liu, Jinyun et al. (2014) Mitochondrial dysfunction in some triple-negative breast cancer cell lines: role of mTOR pathway and therapeutic potential. Breast Cancer Res 16:434|
|Fiskus, Warren; Saba, Nakhle; Shen, Min et al. (2014) Auranofin induces lethal oxidative and endoplasmic reticulum stress and exerts potent preclinical activity against chronic lymphocytic leukemia. Cancer Res 74:2520-32|
|Liu, J; Chen, G; Feng, L et al. (2014) Loss of p53 and altered miR15-a/16-1îˆ²MCL-1 pathway in CLL: insights from TCL1-Tg:p53(-/-) mouse model and primary human leukemia cells. Leukemia 28:118-28|
|Liu, P-P; Liao, J; Tang, Z-J et al. (2014) Metabolic regulation of cancer cell side population by glucose through activation of the Akt pathway. Cell Death Differ 21:124-35|
|Yuan, Shuqiang; Wang, Feng; Chen, Gang et al. (2013) Effective elimination of cancer stem cells by a novel drug combination strategy. Stem Cells 31:23-34|
|Trachootham, Dunyaporn; Chen, Gang; Zhang, Wan et al. (2013) Loss of p53 in stromal fibroblasts promotes epithelial cell invasion through redox-mediated ICAM1 signal. Free Radic Biol Med 58:1-13|
|Garcia-Prieto, Celia; Riaz Ahmed, Kausar Begam; Chen, Zhao et al. (2013) Effective killing of leukemia cells by the natural product OSW-1 through disruption of cellular calcium homeostasis. J Biol Chem 288:3240-50|
|Wen, Shijun; Zhu, Daqian; Huang, Peng (2013) Targeting cancer cell mitochondria as a therapeutic approach. Future Med Chem 5:53-67|
|Xu, Rui-hua; Huang, Peng (2012) A new role for PHD in chemotherapy. Cancer Cell 22:143-4|
Showing the most recent 10 out of 47 publications