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Dysregulation of the miR-34a-SIRT1 axis inhibits breast cancer stemness.

Ma W, Xiao GG, Mao J, Lu Y, Song B, Wang L, Fan S, Fan P, Hou Z, Li J, Yu X, Wang B, Wang H, Wang H, Xu F, Li Y, Liu Q, Li L - Oncotarget (2015)

Bottom Line: Here we found low levels of miR-34a and high levels of SIRT1 in CD44+/CD24- breast cancer stem cells (BCSCs).Expression of CSC markers, ALDH1, BMI1 and Nanog was decreased.Taken together, our results demonstrated that miR-34a inhibits proliferative potential of BCSCs in vitro and in vivo, at least partially by downregulating SIRT1.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Dalian Medical University, Dalian 116044, China.

ABSTRACT
Enforced expression of miR-34a eliminates cancer stem cells in some malignant tumors. Sirtuin-1 (SIRT1) is a direct target of miR-34a. Here we found low levels of miR-34a and high levels of SIRT1 in CD44+/CD24- breast cancer stem cells (BCSCs). MiR-34a overexpression and knockdown of SIRT1 decreased proportion of BSCSs and mammosphere formation. Expression of CSC markers, ALDH1, BMI1 and Nanog was decreased. In nude mice xenografts, stable expression of miR-34a and silencing of SIRT1 reduced tumor burden. Taken together, our results demonstrated that miR-34a inhibits proliferative potential of BCSCs in vitro and in vivo, at least partially by downregulating SIRT1. The miR-34a-SIRT1 axis may play role in self-renewal of BCSCs.

No MeSH data available.


Related in: MedlinePlus

MiR-34a over-expression or silenced SIRT1 inhibit tumor growth in vivoA. Over-expression of miR-34a or silenced SIRT1 remarkably reduced the tumor volume compared to the control groups. *p < 0.05, **p < 0.01. B. Subcutaneous tumor regeneration from MCF-7 cells infected with lentivirus-miR-NC (miR-NC) or lentivirus-miR-34a (miR-34a), or transfected with shRNA-NC(shRNA-NC) or shRNA-SIRT1(shRNA-SIRT1). C. HE and IHC staining with SIRT1 and ALDH1 antibodies. a-d: HE staining; c-l: IHC staining for SIRT1 (brown color in nuclei) and ALDH1 (brown color in cytoplasm), scale bar = 50 μm. D. qRT-PCR analyses of miR-34a expression in each group of xenograft tissues. Compared to each control group, miR-34a or shRNA-SIRT1 group showed a significantly high miR-34a expression level. *p < 0.05. E. Protein levels of SIRT1, and ALDH1 were evaluated by Western blotting analysis in each group of mice tumors (upper). As an internal control, GAPDH was used for normalization. The quantitative results were analyzed by Gel-Pro Analyzer 4.0 software (lower). Data are presented as mean ± SEM, n = 5, *p < 0.05.
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Figure 5: MiR-34a over-expression or silenced SIRT1 inhibit tumor growth in vivoA. Over-expression of miR-34a or silenced SIRT1 remarkably reduced the tumor volume compared to the control groups. *p < 0.05, **p < 0.01. B. Subcutaneous tumor regeneration from MCF-7 cells infected with lentivirus-miR-NC (miR-NC) or lentivirus-miR-34a (miR-34a), or transfected with shRNA-NC(shRNA-NC) or shRNA-SIRT1(shRNA-SIRT1). C. HE and IHC staining with SIRT1 and ALDH1 antibodies. a-d: HE staining; c-l: IHC staining for SIRT1 (brown color in nuclei) and ALDH1 (brown color in cytoplasm), scale bar = 50 μm. D. qRT-PCR analyses of miR-34a expression in each group of xenograft tissues. Compared to each control group, miR-34a or shRNA-SIRT1 group showed a significantly high miR-34a expression level. *p < 0.05. E. Protein levels of SIRT1, and ALDH1 were evaluated by Western blotting analysis in each group of mice tumors (upper). As an internal control, GAPDH was used for normalization. The quantitative results were analyzed by Gel-Pro Analyzer 4.0 software (lower). Data are presented as mean ± SEM, n = 5, *p < 0.05.

Mentions: To further determine whether modulation of miR-34a-SIRT1 axis can inhibit tumorigenesis and tumor growth in vivo, we inoculated 5 × 105 cells stably transfected with either lentivirus-miR-34a or shRNA-SIRT1, into mouse mammary fat pad. Four weeks post-inoculation, mice were sacrificed. We found that treatment of either overexpression miR-34a or silenced SIRT1 inhibited the tumor growth significantly as shown in Figure 5A. The macroscopic tumors were observed in 5 of 5 nude mice among groups of miR-34a and two control groups (miR-NC and ShRNA-NC) except for ShRNA-SIRT1 group, which the macroscopic tumors were observed only in 4 of 5 nude mice. The final tumor size in mice from groups treated either with shRNA-SIRT1 or miR-34a was significantly smaller than the control groups on day 28 when sacrificed (Figure 5B).


Dysregulation of the miR-34a-SIRT1 axis inhibits breast cancer stemness.

Ma W, Xiao GG, Mao J, Lu Y, Song B, Wang L, Fan S, Fan P, Hou Z, Li J, Yu X, Wang B, Wang H, Wang H, Xu F, Li Y, Liu Q, Li L - Oncotarget (2015)

MiR-34a over-expression or silenced SIRT1 inhibit tumor growth in vivoA. Over-expression of miR-34a or silenced SIRT1 remarkably reduced the tumor volume compared to the control groups. *p < 0.05, **p < 0.01. B. Subcutaneous tumor regeneration from MCF-7 cells infected with lentivirus-miR-NC (miR-NC) or lentivirus-miR-34a (miR-34a), or transfected with shRNA-NC(shRNA-NC) or shRNA-SIRT1(shRNA-SIRT1). C. HE and IHC staining with SIRT1 and ALDH1 antibodies. a-d: HE staining; c-l: IHC staining for SIRT1 (brown color in nuclei) and ALDH1 (brown color in cytoplasm), scale bar = 50 μm. D. qRT-PCR analyses of miR-34a expression in each group of xenograft tissues. Compared to each control group, miR-34a or shRNA-SIRT1 group showed a significantly high miR-34a expression level. *p < 0.05. E. Protein levels of SIRT1, and ALDH1 were evaluated by Western blotting analysis in each group of mice tumors (upper). As an internal control, GAPDH was used for normalization. The quantitative results were analyzed by Gel-Pro Analyzer 4.0 software (lower). Data are presented as mean ± SEM, n = 5, *p < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
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Figure 5: MiR-34a over-expression or silenced SIRT1 inhibit tumor growth in vivoA. Over-expression of miR-34a or silenced SIRT1 remarkably reduced the tumor volume compared to the control groups. *p < 0.05, **p < 0.01. B. Subcutaneous tumor regeneration from MCF-7 cells infected with lentivirus-miR-NC (miR-NC) or lentivirus-miR-34a (miR-34a), or transfected with shRNA-NC(shRNA-NC) or shRNA-SIRT1(shRNA-SIRT1). C. HE and IHC staining with SIRT1 and ALDH1 antibodies. a-d: HE staining; c-l: IHC staining for SIRT1 (brown color in nuclei) and ALDH1 (brown color in cytoplasm), scale bar = 50 μm. D. qRT-PCR analyses of miR-34a expression in each group of xenograft tissues. Compared to each control group, miR-34a or shRNA-SIRT1 group showed a significantly high miR-34a expression level. *p < 0.05. E. Protein levels of SIRT1, and ALDH1 were evaluated by Western blotting analysis in each group of mice tumors (upper). As an internal control, GAPDH was used for normalization. The quantitative results were analyzed by Gel-Pro Analyzer 4.0 software (lower). Data are presented as mean ± SEM, n = 5, *p < 0.05.
Mentions: To further determine whether modulation of miR-34a-SIRT1 axis can inhibit tumorigenesis and tumor growth in vivo, we inoculated 5 × 105 cells stably transfected with either lentivirus-miR-34a or shRNA-SIRT1, into mouse mammary fat pad. Four weeks post-inoculation, mice were sacrificed. We found that treatment of either overexpression miR-34a or silenced SIRT1 inhibited the tumor growth significantly as shown in Figure 5A. The macroscopic tumors were observed in 5 of 5 nude mice among groups of miR-34a and two control groups (miR-NC and ShRNA-NC) except for ShRNA-SIRT1 group, which the macroscopic tumors were observed only in 4 of 5 nude mice. The final tumor size in mice from groups treated either with shRNA-SIRT1 or miR-34a was significantly smaller than the control groups on day 28 when sacrificed (Figure 5B).

Bottom Line: Here we found low levels of miR-34a and high levels of SIRT1 in CD44+/CD24- breast cancer stem cells (BCSCs).Expression of CSC markers, ALDH1, BMI1 and Nanog was decreased.Taken together, our results demonstrated that miR-34a inhibits proliferative potential of BCSCs in vitro and in vivo, at least partially by downregulating SIRT1.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Dalian Medical University, Dalian 116044, China.

ABSTRACT
Enforced expression of miR-34a eliminates cancer stem cells in some malignant tumors. Sirtuin-1 (SIRT1) is a direct target of miR-34a. Here we found low levels of miR-34a and high levels of SIRT1 in CD44+/CD24- breast cancer stem cells (BCSCs). MiR-34a overexpression and knockdown of SIRT1 decreased proportion of BSCSs and mammosphere formation. Expression of CSC markers, ALDH1, BMI1 and Nanog was decreased. In nude mice xenografts, stable expression of miR-34a and silencing of SIRT1 reduced tumor burden. Taken together, our results demonstrated that miR-34a inhibits proliferative potential of BCSCs in vitro and in vivo, at least partially by downregulating SIRT1. The miR-34a-SIRT1 axis may play role in self-renewal of BCSCs.

No MeSH data available.


Related in: MedlinePlus