Let‑7 miRNAs sensitize breast cancer stem cells to radiation‑induced repression through inhibition of the cyclin D1/Akt1/Wnt1 signaling pathway

Sun,Huifang; Ding,Changmao; Zhang,Huiyu; Gao,Jianbo

doi:10.3892/mmr.2016.5656

Let‑7 miRNAs sensitize breast cancer stem cells to radiation‑induced repression through inhibition of the cyclin D1/Akt1/Wnt1 signaling pathway

Authors:
- Huifang Sun
- Changmao Ding
- Huiyu Zhang
- Jianbo Gao
View Affiliations

Affiliations: Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
Published online on: August 19, 2016 https://doi.org/10.3892/mmr.2016.5656
Pages: 3285-3292

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

The tumor-suppressive let-7 family of microRNAs (miRNAs) has been previously identified to induce cell apoptosis, proliferation‑inhibition and suppression of the self‑renewal capacities of cancer stem cells (CSCs). However, let‑7‑mediated sensitization of tumors to radiation treatment remains to be investigated fully in triple negative breast cancer (TNBC), of which the clinical treatment is challenging. The inhibitory effect of let‑7 miRNAs on the self‑renewal ability of CSCs from TNBC was investigated. It was identified that radiation inhibited the self‑renewal ability of TNBC stem cells by inhibiting cyclin D1 and protein kinase B (Akt1) phosphorylation. Let‑7d stimulates radiation‑induced tumor repression, exerting synergistic effects with radiotherapy on stem cell renewal. Through western blotting, immunofluorescence and a luciferase assay, it was identified that reduced cyclin D1/Akt1/wingless type MMTV integration site family member 1 (Wnt1) signaling activity accounts for the let‑7‑induced radiation sensitization. Let‑7 directly inhibits cyclin D1 expression, resulting in low phosphorylation of Akt1, which is critical for the let‑7‑induced inhibition of mammosphere numbers. The let‑7d‑induced Akt1 inhibition contributed to tumor repression, with similar results to those obtained with Akt inhibitors. Furthermore, it was identified that the inhibition of Wnt1 is critical for the functioning of let‑7d, and that addition of recombinant Wnt1 abolished the effects of let‑7d on sensitization to radiotherapy. Let‑7d is suggested to be a promising therapeutic agent in the treatment of TNBC by targeting CSCs and sensitizing tumors to radiotherapy via inhibition of cyclin D1/Akt1/Wnt1 signaling.

View Figures

View References

1	Jemal A, Bray F, Center MM, Ferlay J, Ward E and Forman D: Global cancer statistics. CA Cancer J Clin. 61:69–90. 2011. View Article : Google Scholar : PubMed/NCBI
2	Desmedt C, Haibe-Kains B, Wirapati P, Buyse M, Larsimont D, Bontempi G, Delorenzi M, Piccart M and Sotiriou C: Biological processes associated with breast cancer clinical outcome depend on the molecular subtypes. Clin Cancer Res. 14:5158–5165. 2008. View Article : Google Scholar : PubMed/NCBI
3	Tran B and Bedard PL: Luminal-B breast cancer and novel therapeutic targets. Breast Cancer Res. 13:2212011. View Article : Google Scholar
4	Hayes EL and Lewis-Wambi JS: Mechanisms of endocrine resistance in breast cancer: An overview of the proposed roles of noncoding RNA. Breast Cancer Res. 17:402015. View Article : Google Scholar : PubMed/NCBI
5	Sotiriou C, Neo SY, McShane LM, Korn EL, Long PM, Jazaeri A, Martiat P, Fox SB, Harris AL and Liu ET: Breast cancer classification and prognosis based on gene expression profiles from a population-based study. Proc Natl Acad Sci USA. 100:10393–10398. 2003. View Article : Google Scholar : PubMed/NCBI
6	Assi HA, Khoury KE, Dbouk H, Khalil LE, Mouhieddine TH and El Saghir NS: Epidemiology and prognosis of breast cancer in young women. J Thorac Dis. 5(Suppl 1): S2–S8. 2013.PubMed/NCBI
7	Sun X, Jiao X, Pestell TG, Fan C, Qin S, Mirabelli E, Ren H and Pestell RG: MicroRNAs and cancer stem cells: The sword and the shield. Oncogene. 33:4967–4977. 2014. View Article : Google Scholar
8	Rothschild SI: microRNA therapies in cancer. Mol Cell Ther. 2:72014. View Article : Google Scholar : PubMed/NCBI
9	Costa PM and Pedroso de Lima MC: MicroRNAs as molecular targets for cancer therapy: On the modulation of microRNA expression. Pharmaceuticals (Basel). 6:1195–1220. 2013. View Article : Google Scholar
10	Sun X, Tang SC, Xu C, Wang C, Qin S, Du N, Liu J, Zhang Y, Li X, Luo G, et al: Dicer regulated let-7 expression levels in p53-induced cancer repression requires cyclin D1. J Cell Mol Med. 19:1357–1365. 2015. View Article : Google Scholar : PubMed/NCBI
11	Cai J, Guan H, Fang L, Yang Y, Zhu X, Yuan J, Wu J and Li M: MicroRNA-374a activates Wnt/β-catenin signaling to promote breast cancer metastasis. J Clin Invest. 123:566–579. 2013.PubMed/NCBI
12	Laezza C, d'Alessandro A, Malfitano AM and Bifulco M: Anandamide inhibits the Wnt/β-catenin signalling pathway in human breast cancer MDA MB 231 cells. Eur J Cancer. 49:2066–2067. 2013. View Article : Google Scholar : PubMed/NCBI
13	Malanchi I, Santamaria-Martinez A, Susanto E, Peng H, Lehr HA, Delaloye JF and Huelsken J: Interactions between cancer stem cells and their niche govern metastatic colonization. Nature. 481:85–89. 2011. View Article : Google Scholar : PubMed/NCBI
14	Livak KJ and Schmittgen TD: Analysis of relative gene expression data using real-time quantitative PCR and the 2(−Delta Delta C(T)) method. Methods. 25:402–408. 2001. View Article : Google Scholar
15	Cicalese A, Bonizzi G, Pasi CE, Faretta M, Ronzoni S, Giulini B, Brisken C, Minucci S, Di Fiore PP and Pelicci PG: The tumor suppressor p53 regulates polarity of self-renewing divisions in mammary stem cells. Cell. 138:1083–1095. 2009. View Article : Google Scholar : PubMed/NCBI
16	Oliveras-Ferraros C, Cufi S, Vazquez-Martin A, Torres-Garcia VZ, Del Barco S, Martin-Castillo B and Menendez JA: Micro (mi) RNA expression profile of breast cancer epithelial cells treated with the anti-diabetic drug metformin: Induction of the tumor suppressor miRNA let-7a and suppression of the TGFβ-induced oncomiR miRNA-181a. Cell Cycle. 10:1144–1151. 2011. View Article : Google Scholar : PubMed/NCBI
17	Sun Y, Wang Y, Fan C, Gao P, Wang X, Wei G and Wei J: Estrogen promotes stemness and invasiveness of ER-positive breast cancer cells through Gli1 activation. Mol Cancer. 13:1372014. View Article : Google Scholar : PubMed/NCBI
18	Zhou J, Wang C, Wang Z, Dampier W, Wu K, Casimiro MC, Chepelev I, Popov VM, Quong A, Tozeren A, et al: Attenuation of Forkhead signaling by the retinal determination factor DACH1. Proc Natl Acad Sci USA. 107:6864–6869. 2010. View Article : Google Scholar : PubMed/NCBI
19	Johnson CD, Esquela-Kerscher A, Stefani G, Byrom M, Kelnar K, Ovcharenko D, Wilson M, Wang X, Shelton J, Shingara J, et al: The let-7 microRNA represses cell proliferation pathways in human cells. Cancer Res. 67:7713–7722. 2007. View Article : Google Scholar : PubMed/NCBI
20	Tsang WP and Kwok TT: Let-7a microRNA suppresses therapeutics-induced cancer cell death by targeting caspase-3. Apoptosis. 13:1215–1222. 2008. View Article : Google Scholar : PubMed/NCBI
21	Saridaki Z, Weidhaas JB, Lenz HJ, Laurent-Puig P, Jacobs B, De Schutter J, De Roock W, Salzman DW, Zhang W, Yang D, et al: A let-7 microRNA-binding site polymorphism in KRAS predicts improved outcome in patients with metastatic colorectal cancer treated with salvage cetuximab/panitumumab monotherapy. Clin Cancer Res. 20:4499–4510. 2014. View Article : Google Scholar : PubMed/NCBI
22	Worringer KA, Rand TA, Hayashi Y, Sami S, Takahashi K, Tanabe K, Narita M, Srivastava D and Yamanaka S: The let-7/LIN-41 pathway regulates reprogramming to human induced pluripotent stem cells by controlling expression of prodifferentiation genes. Cell Stem Cell. 14:40–52. 2014. View Article : Google Scholar
23	Anastas JN and Moon RT: WNT signalling pathways as therapeutic targets in cancer. Nat Rev Cancer. 13:11–26. 2013. View Article : Google Scholar
24	Ohno S, Takanashi M, Sudo K, Ueda S, Ishikawa A, Matsuyama N, Fujita K, Mizutani T, Ohgi T, Ochiya T, et al: Systemically injected exosomes targeted to EGFR deliver antitumor microrna to breast cancer cells. Mol Ther. 21:185–191. 2013. View Article : Google Scholar :
25	Laezza C, D'Alessandro A, Paladino S, Maria Malfitano A, Chiara Proto M, Gazzerro P, Pisanti S, Santoro A, Ciaglia E and Bifulco M; Endocannabinoid Research Group: Anandamide inhibits the Wnt/β-catenin signalling pathway in human breast cancer MDA MB 231 cells. Eur J Cancer. 48:3112–3122. 2012. View Article : Google Scholar : PubMed/NCBI
26	Taurin S, Sandbo N, Yau DM, Sethakorn N and Dulin NO: Phosphorylation of beta-catenin by PKA promotes ATP-induced proliferation of vascular smooth muscle cells. Am J Physiol Cell Physiol. 294:C1169–C1174. 2008. View Article : Google Scholar : PubMed/NCBI
27	Midwood KS and Orend G: The role of tenascin-C in tissue injury and tumorigenesis. J Cell Commun Signal. 3:287–310. 2009. View Article : Google Scholar : PubMed/NCBI
28	Choi AR, Park JR, Kim RJ, Kim SR, Cho SD, Jung JY and Nam JS: Inhibition of Wnt1 expression reduces the enrichment of cancer stem cells in a mouse model of breast cancer. Biochem Biophys Res Commun. 425:436–442. 2012. View Article : Google Scholar : PubMed/NCBI
29	Katoh M and Katoh M: WNT signaling pathway and stem cell signaling network. Clin Cancer Res. 13:4042–4045. 2007. View Article : Google Scholar : PubMed/NCBI
30	He B and Jablons DM: Wnt signaling in stem cells and lung cancer. Cancer Stem Cells. Wiestler OD, Haendler B and Mumberg D: Springer-Verlag; Berlin: pp. 27–58. 2007, View Article : Google Scholar
31	Sun X, Qin S, Fan C, Xu C, Du N and Ren H: Let-7: A regulator of the ERalpha signaling pathway in human breast tumors and breast cancer stem cells. Oncol Rep. 29:2079–2087. 2013.PubMed/NCBI