- 作者: Ming-Jer Young, Yung-Ching Chen, Shao-An Wang, Hui-Ping Chang, Wen-Bin Yang, Chia-Chi Lee, Chia-Yu Liu, Yau-Lin Tseng, Yi-Ching Wang, H. Sunny Sun, Wen-Chang Chang & Jan-Jong Hung
- 作者服務機構: 1.Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan 2.Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan 3.Division of Thoracic Surgery, Department of Surgery, College of Medicine National, Cheng Kung University, Tainan, Taiwan 4.Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan 5.Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan 6.School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan 7.The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan 8.TMU Research Center of Neuroscience, Taipei Medical University, 11031, Taipei, Taiwan
- 中文摘要:
- 英文摘要:
Background:
Sp1, an important transcription factor, is involved in the progression of various cancers. Our previous studies have indicated that Sp1 levels are increased in the early stage of lung cancer progression but decrease during the late stage, leading to poor prognosis. In addition, estrogen has been shown to be involved in lung cancer progres sion. According to previous studies, Sp1 can interact with the estrogen receptor (ER) to coregulate gene expression. The role of interaction between Sp1 and ER in lung cancer progression is still unknown and will be clarifed in this study.
Methods:
The clinical relevance between Sp1 levels and survival rates in young women with lung cancer was stud ied by immunohistochemistry. We validated the sex dependence of lung cancer progression in EGFRL858R-induced lung cancer mice. Wound healing assays, chamber assays and sphere formation assays in A549 cells, Taxol-induced drug-resistant A549 (A549-T24) and estradiol (E2)-treated A549 (E2-A549) cells were performed to investigate the roles of Taxol and E2 in lung cancer progression. Luciferase reporter assays, immunoblot and q-PCR were performed to evaluate the interaction between Sp1, microRNAs and CD44. Tail vein-injected xenograft experiments were per formed to study lung metastasis. Samples obtained from lung cancer patients were used to study the mRNA level of CD44 by q-PCR and the protein levels of Sp1 and CD44 by immunoblot and immunohistochemistry.
Results:
In this study, we found that Sp1 expression was decreased in premenopausal women with late-stage lung cancer, resulting in a poor prognosis. Tumor formation was more substantial in female EGFRL858R mice than in male mice and ovariectomized female mice, indicating that E2 might be involved in the poor prognosis of lung cancer. We herein report that Sp1 negatively regulates metastasis and cancer stemness in E2-A549 and A549-T24 cells. Further more, E2 increases the mRNA and protein levels of RING fnger protein 4 (RNF4), which is the E3-ligase of Sp1, and thereby decreases Sp1 levels by promoting Sp1 degradation. Sp1 can be recruited to the promoter of miR-3194-5p, and positively regulate its expression. Furthermore, there was a strong inverse correlation between Sp1 and CD44 levels in clinical lung cancer specimens. Sp1 inhibited CD44 expression by increasing the expression of miR-3194-5p, miR-218-5p, miR-193-5p, miR-182-5p and miR-135-5p, ultimately resulting in lung cancer malignancy.
Conclusion:
Premenopausal women with lung cancer and decreased Sp1 levels have a poor prognosis. E2 increases RNF4 expression to repress Sp1 levels in premenopausal women with lung cancer, thus decreasing the expression of several miRNAs that can target CD44 and ultimately leading to cancer malignancy.
- 中文關鍵字:
- 英文關鍵字: Sp1, Estradiol (E2), microRNAs, CD44, RNF4, Lung cancer