Rationale: Cancer stem cells (CSCs) have been implicated as the seeds of therapeutic resistance and metastasis, due to their unique abilities of self-renew, wide differentiation potentials and resistance to most conventional therapies. It is a proactive strategy for cancer therapy to eradicate CSCs. Methods: Tumor tissue-derived breast CSCs (BCSC), including XM322 and XM607, were isolated by fluorescence-activated cell sorting (FACS); while cell line-derived BCSC, including MDA-MB-231.SC and MCF-7.SC, were purified by magnetic-activated cell sorting (MACS). Analyses of microRNA and mRNA expression array profiles were performed in multiple breast cell lines. The mentioned nanoparticles were constructed following the standard molecular cloning protocol. Tissue microarray analysis has been used to study 217 cases of clinical breast cancer specimens. Results: Here, we have successfully established four long-term maintenance BCSC that retain their tumor-initiating biological properties. Our analyses of microarray and qRT-PCR explored that miR-34a is the most pronounced microRNA for investigation of BCSC. We establish hTERT promoter-driven VISA delivery of miR-34a (TV-miR-34a) plasmid that can induce high throughput of miR-34a expression in BCSC. TV-miR-34a significantly inhibited the tumor-initiating properties of long-term-cultured BCSC in vitro and reduced the proliferation of BCSC in vivo by an efficient and safe way. TV-miR-34a synergizes with docetaxel, a standard therapy for invasive breast cancer, to act as a BCSC inhibitor. Further mechanistic investigation indicates that TV-miR-34a directly prevents C22ORF28 accumulation, which abrogates clonogenicity and tumor growth and correlates with low miR-34 and high C22ORF28 levels in breast cancer patients. Conclusion: Taken together, we generated four long-term maintenance BCSC derived from either clinical specimens or cell lines, which would be greatly beneficial to the research progress in breast cancer patients. We further developed the non-viral TV-miR-34a plasmid, which has a great potential to be applied as a clinical application for breast cancer therapy.

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Published in Theranostics, v. 7, issue 19, p. 4805-4824.

© Ivyspring International Publisher.

This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/). See http://ivyspring.com/terms for full terms and conditions.

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This work was supported by funds from the Key Program of the National Natural Science Foundation of China (31030061), the National Natural Science Foundation of China (81272514 and 81472575), the China Postdoctoral Science Foundation (2017M610570), Natural Science Foundation of Guangdong (2013B060300009), Science and Technology Planning Project of Guangzhou (2014J4100169), Guiding Project of Science and Technology Department of Fujian Province (2016Y0020), Training Project Funding Plan of Young and Middle-aged Talent of Health System in Fujian Province (2016-ZQN-18), Training Project Funding Plan of Youth Innovative Talents of Xiamen City (2017), and Sisters Hospital Network Fund (SINF) between University of Texas MD Anderson Cancer Center and Sun Yat-sen University Cancer Center.

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Supplementary methods, tables (S1-S6) and figures(S1-S4). http://www.thno.org/v07p4805s1.pdf

thnov07p4805s1.pdf (10980 kB)
Supplementary methods, tables (S1-S6) and figures (S1-S4).