Let‑7a suppresses cell proliferation via the TGF‑β/SMAD signaling pathway in cervical cancer

Wu,Tianhui; Chen,Xin; Peng,Rui; Liu,Handeng; Yin,Pin; Peng,Huimin; Zhou,Yujian; Sun,Yan; Wen,Li; Yi,Hong; Li,Ailing; Zhang,Zheng

doi:10.3892/or.2016.5160

Let‑7a suppresses cell proliferation via the TGF‑β/SMAD signaling pathway in cervical cancer

Authors:
- Tianhui Wu
- Xin Chen
- Rui Peng
- Handeng Liu
- Pin Yin
- Huimin Peng
- Yujian Zhou
- Yan Sun
- Li Wen
- Hong Yi
- Ailing Li
- Zheng Zhang
View Affiliations

Affiliations: Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, P.R. China, Department of Surgery, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400010, P.R. China
Published online on: October 11, 2016 https://doi.org/10.3892/or.2016.5160
Pages: 3275-3282

Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )

Metrics: Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )

Cited By (CrossRef): 0 citations Loading Articles...

Abstract

Cervical cancer is the second most commonly diagnosed type of cancer among women after breast cancer. Recent research has addressed the role of microRNAs in cervical cancer. In the present study, we aimed to determine the effect of let‑7a on the regulation of the cell proliferation of cervical cancer and the related signaling pathway. Real‑time RT‑PCR was used to detect the expression of let‑7a in the blood of cervical cancer patients and normal controls. The expression of let‑7a was also assessed in cervical cancer cell lines: HeLa, SiHa and normal human immortalized keratinocyes HaCaT. Cell proliferation was tested by MTT assay, and cell apoptosis and cell cycle were examined by flow cytometric analysis in HeLa cells. Moreover, bioinformatic analysis, dual‑luciferase reporter assay and western blotting were used to confirm the target gene for let‑7a. In addition, the expression of TGF‑β1, SMAD4 and p53 were assessed by western blotting and real‑time PCR. Our studies showed that the expression of let‑7a in cervical cancer was significantly reduced in cervical cancer patients compared with the expression in the normal control group. Cell proliferation of HeLa cells was inhibited by overexpression of let‑7a. The cell cycle analysis showed that an increased population was arrested in the G2 phase in the let‑7a mimic group when compared with that in the mimic control and untreated groups. In addition, the cell cycle‑related factor p53 was increased in the let‑7a overexpression group compared with that in the control and untreated groups. Furthermore, TGFBR1 was confirmed to be a target of let‑7a. Moreover, the expression of TGF‑β1 and SMAD4 proteins was elevated in cervical squamous carcinoma and cervical adenocarcinoma tissues. However, the expression of TGF‑β1 and SMAD4 was decreased in the let‑7a‑overexpressing cervical cancer cell lines (HeLa, SiHa and CaSki). Our data suggest that let‑7a may play a role in the cell proliferation of cervical cancer by regulating the TGF‑β/SMAD pathway, and may participate in the regulation of the occurrence and development of cervical cancer.

View Figures

View References

1	Haie-Meder C, Morice P and Castiglione M: ESMO Guidelines Working Group: Cervical cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 21:(Suppl 5). v37–v40. 2010. View Article : Google Scholar : PubMed/NCBI
2	Castellsagué X, Díaz M, de Sanjosé S, Muñoz N, Herrero R, Franceschi S, Peeling RW, Ashley R, Smith JS, Snijders PJ, et al: International Agency for Research on Cancer Multicenter Cervical Cancer Study Group: Worldwide human papillomavirus etiology of cervical adenocarcinoma and its cofactors: Implications for screening and prevention. J Natl Cancer Inst. 98:303–315. 2006. View Article : Google Scholar : PubMed/NCBI
3	Aranha MM, Santos DM, Xavier JM, Low WC, Steer CJ, Solá S and Rodrigues CM: Apoptosis-associated microRNAs are modulated in mouse, rat and human neural differentiation. BMC Genomics. 11:5142010. View Article : Google Scholar : PubMed/NCBI
4	Schwarzenbacher D, Balic M and Pichler M: The role of microRNAs in breast cancer stem cells. Int J Mol Sci. 14:14712–14723. 2013. View Article : Google Scholar : PubMed/NCBI
5	Lawrie CH, Gal S, Dunlop HM, Pushkaran B, Liggins AP, Pulford K, Banham AH, Pezzella F, Boultwood J, Wainscoat JS, et al: Detection of elevated levels of tumour-associated microRNAs in serum of patients with diffuse large B-cell lymphoma. Br J Haematol. 141:672–675. 2008. View Article : Google Scholar : PubMed/NCBI
6	Mitchell PS, Parkin RK, Kroh EM, Fritz BR, Wyman SK, Pogosova-Agadjanyan EL, Peterson A, Noteboom J, O'Briant KC, Allen A, et al: Circulating microRNAs as stable blood-based markers for cancer detection. Proc Natl Acad Sci USA. 105:10513–10518. 2008. View Article : Google Scholar : PubMed/NCBI
7	Ho AS, Huang X, Cao H, Christman-Skieller C, Bennewith K, Le QT and Koong AC: Circulating miR-210 as a novel hypoxia marker in pancreatic cancer. Transl Oncol. 3:109–113. 2010. View Article : Google Scholar : PubMed/NCBI
8	Tsujiura M, Ichikawa D, Komatsu S, Shiozaki A, Takeshita H, Kosuga T, Konishi H, Morimura R, Deguchi K, Fujiwara H, et al: Circulating microRNAs in plasma of patients with gastric cancers. Br J Cancer. 102:1174–1179. 2010. View Article : Google Scholar : PubMed/NCBI
9	Xia XM, Jin WY, Shi RZ, Zhang YF and Chen J: Clinical significance and the correlation of expression between Let-7 and K-ras in non-small cell lung cancer. Oncol Lett. 1:1045–1047. 2010.PubMed/NCBI
10	Kong D, Heath E, Chen W, Cher ML, Powell I, Heilbrun L, Li Y, Ali S, Sethi S, Hassan O, et al: Loss of let-7 up-regulates EZH2 in prostate cancer consistent with the acquisition of cancer stem cell signatures that are attenuated by BR-DIM. PLoS One. 7:e337292012. View Article : Google Scholar : PubMed/NCBI
11	Mayr C, Hemann MT and Bartel DP: Disrupting the pairing between let-7 and Hmga2 enhances oncogenic transformation. Science. 315:1576–1579. 2007. View Article : Google Scholar : PubMed/NCBI
12	He XY, Chen JX, Zhang Z, Li CL, Peng QL and Peng HM: The let-7a microRNA protects from growth of lung carcinoma by suppression of k-Ras and c-Myc in nude mice. J Cancer Res Clin Oncol. 136:1023–1028. 2010. View Article : Google Scholar : PubMed/NCBI
13	Zhou J, Peng R, Li T, Luo X, Peng H, Zha H, Yin P, Wen L and Zhang Z: A potentially functional polymorphism in the regulatory region of let-7a-2 is associated with an increased risk for diabetic nephropathy. Gene. 527:456–461. 2013. View Article : Google Scholar : PubMed/NCBI
14	Lee JW, Choi CH, Choi JJ, Park YA, Kim SJ, Hwang SY, Kim WY, Kim TJ, Lee JH, Kim BG, et al: Altered MicroRNA expression in cervical carcinomas. Clin Cancer Res. 14:2535–2542. 2008. View Article : Google Scholar : PubMed/NCBI
15	Fan DM, Tian XY, Wang RF and Yu JJ: The prognosis significance of TGF-β1 and ER protein in cervical adenocarcinoma patients with stage Ib~IIa. Tumour Biol. 35:11237–11242. 2014. View Article : Google Scholar : PubMed/NCBI
16	Chu GC, Dunn NR, Anderson DC, Oxburgh L and Robertson EJ: Differential requirements for Smad4 in TGFbeta-dependent patterning of the early mouse embryo. Development. 131:3501–3512. 2004. View Article : Google Scholar : PubMed/NCBI
17	López-Muñoz H, Escobar-Sánchez ML, López-Marure R, Lascurain-Ledesma R, Zenteno E, Hernández-Vazquez JM, Weiss-Steider B and Sánchez-Sánchez L: Cervical cancer cells induce apoptosis in TCD4⁺ lymphocytes through the secretion of TGF-β. Arch Gynecol Obstet. 287:755–763. 2013. View Article : Google Scholar : PubMed/NCBI
18	Bai X, He T, Liu J, Wang Y, Fan L, Tao K, Shi J, Tang C, Su L and Hu D: Loureirin B inhibits fibroblast proliferation and extracellular matrix deposition in hypertrophic scar via TGF-β/Smad pathway. Exp Dermatol. 24:355–360. 2015. View Article : Google Scholar : PubMed/NCBI
19	Feng XH and Derynck R: Specificity and versatility in tgf-beta signaling through Smads. Annu Rev Cell Dev Biol. 21:659–693. 2005. View Article : Google Scholar : PubMed/NCBI
20	Pasche B, Pennison MJ, Jimenez H and Wang M: TGFBR1 and cancer susceptibility. Trans Am Clin Climatol Assoc. 125:300–312. 2014.PubMed/NCBI
21	Sun Y, Peng R, Peng H, Liu H, Wen L, Wu T, Yi H, Li A and Zhang Z: miR-451 suppresses the NF-kappaB-mediated proinflammatory molecules expression through inhibiting LMP7 in diabetic nephropathy. Mol Cel Endocrinol. 433:75–86. 2016. View Article : Google Scholar
22	Shishodia G, Shukla S, Srivastava Y, Masaldan S, Mehta S, Bhambhani S, Sharma S, Mehrotra R, Das BC and Bharti AC: Alterations in microRNAs miR-21 and let-7a correlate with aberrant STAT3 signaling and downstream effects during cervical carcinogenesis. Mol Cancer. 14:1162015. View Article : Google Scholar : PubMed/NCBI
23	Nair VS, Maeda LS and Ioannidis JP: Clinical outcome prediction by microRNAs in human cancer: A systematic review. J Natl Cancer Inst. 104:528–540. 2012. View Article : Google Scholar : PubMed/NCBI
24	Shell S, Park SM, Radjabi AR, Schickel R, Kistner EO, Jewell DA, Feig C, Lengyel E and Peter ME: Let-7 expression defines two differentiation stages of cancer. Proc Natl Acad Sci USA. 104:11400–11405. 2007. View Article : Google Scholar : PubMed/NCBI
25	Serguienko A, Grad I, Wennerstrøm AB, Meza-Zepeda LA, Thiede B, Stratford EW, Myklebost O and Munthe E: Metabolic reprogramming of metastatic breast cancer and melanoma by let-7a microRNA. Oncotarget. 10:2451–2465. 2015. View Article : Google Scholar
26	Dong Q, Meng P, Wang T, Qin W, Qin W, Wang F, Yuan J, Chen Z, Yang A and Wang H: MicroRNA let-7a inhibits proliferation of human prostate cancer cells in vitro and in vivo by targeting E2F2 and CCND2. PLoS One. 5:e101472010. View Article : Google Scholar : PubMed/NCBI
27	Zhong Z, Dong Z, Yang L, Chen X and Gong Z: Inhibition of proliferation of human lung cancer cells by green tea catechins is mediated by upregulation of let-7. Exp Ther Med. 4:267–272. 2014.
28	Song H, Xu W, Song J, Liang Y, Fu W, Zhu XC, Li C, Peng JS and Zheng JN: Overexpression of Lin28 inhibits the proliferation, migration and cell cycle progression and induces apoptosis of BGC-823 gastric cancer cells. Oncol Rep. 33:997–1003. 2015.PubMed/NCBI
29	Lee JY, Kim HJ, Yoon NA, Lee WH, Min YJ, Ko BK, Lee BJ, Lee A, Cha HJ, Cho WJ, et al: Tumor suppressor p53 plays a key role in induction of both tristetraprolin and let-7 in human cancer cells. Nucleic Acids Res. 41:5614–5625. 2013. View Article : Google Scholar : PubMed/NCBI
30	Akhurst RJ and Hata A: Targeting the TGFβ signalling pathway in disease. Nat Rev Drug Discov. 11:790–811. 2012. View Article : Google Scholar : PubMed/NCBI
31	Lei Z, Xu G, Wang L, Yang H, Liu X, Zhao J and Zhang HT: MiR-142-3p represses TGF-β-induced growth inhibition through repression of TGFβR1 in non-small cell lung cancer. FASEB J. 28:2696–2704. 2014. View Article : Google Scholar : PubMed/NCBI
32	Fang Y, Chen Y, Yu L, Zheng C, Qi Y, Li Z, Yang Z, Zhang Y, Shi T, Luo J, et al: Inhibition of breast cancer metastases by a novel inhibitor of TGFβ receptor 1. J Natl Cancer Inst. 105:47–58. 2013. View Article : Google Scholar : PubMed/NCBI