ALDH1+ stem cells demonstrate more stem cell-like characteristics than CD44+/CD24-/low stem cells in different molecular subtypes of breast cancer

Jie Chen; Shiwei Liu; Yingying Su; Xiao Zhang

doi:10.21037/tcr.2020.01.53

ALDH1+ stem cells demonstrate more stem cell-like characteristics than CD44⁺/CD24^-/low stem cells in different molecular subtypes of breast cancer

Transl Cancer Res. 2020 Mar;9(3):1652-1659. doi: 10.21037/tcr.2020.01.53.

Authors

Jie Chen^#¹, Shiwei Liu^#², Yingying Su³, Xiao Zhang¹

Affiliations

¹ Department of Breast Surgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 611731, China.
² Department of Breast Surgery, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China.
³ Department of Breast and Thyroid Surgery, The Third Affiliated Hospital of Zunyi Medical University (The First People's Hospital of Zunyi), Zunyi 563000, China.

^# Contributed equally.

Abstract

Background: CD44⁺/CD24 ^- ^/low and ALDH1+ are both markers of breast cancer stem cell (BCSC), we compared the biological characteristics of CD44⁺/CD24 ^- ^/low and ALDH1+ BCSCs in the four molecular subtypes of breast cancer.

Methods: Four fresh blocks of breast cancer tissue were obtained from patients with Luminal A, Luminal B, human epidermal receptor-2 (HER2)-overexpression and triple-negative breast cancer, respectively. Flow cytometry was used to sort CD44⁺/CD24 ^- ^/low and ALDH1+ BCSCs. The mammosphere (MS) formation experiment and NOD/SCID mouse xenograft experiment were performed to compare the self-renewal and tumorigenic abilities of CD44⁺/CD24 ^- ^/low with those of ALDH1+ BCSCs.

Results: The proportions of CD44⁺/CD24 ^- ^/low BCSC and ALDH1+ BCSC in Luminal A, Luminal B, HER2 overexpression and triple-negative subtypes were 12.1% and 8.7%, 2.7% and 5.7%, 0.8% and 8.7%, 0.7% and 4.5%, respectively. The MS formation experiment demonstrated that ALDH1+ BCSC formed significantly more MSs than CD44⁺/CD24 ^- ^/low BCSC in the four molecular subtypes (P<0.001). The NOD/SCID mouse xenograft experiment demonstrated that the sizes of grafted tumors formed by ALDH1+ BCSC were larger than those formed by CD44⁺/CD24 ^- ^/low BCSC in the four molecular subtypes (P<0.05).

Conclusions: In the four molecular subtypes of breast cancer, ALDH1+ BCSC demonstrated better self-renewal and tumorigenic abilities than CD44⁺/CD24 ^- ^/low BCSC.

Keywords: ALDH1+; Breast cancer; CD44+/CD24–/low; breast cancer stem cell (BCSC); molecular subtype.