Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Mar 8:9:644851.
doi: 10.3389/fcell.2021.644851. eCollection 2021.

Autophagy Mediates Leptin-Induced Migration and ERK Activation in Breast Cancer Cells

Affiliations

Autophagy Mediates Leptin-Induced Migration and ERK Activation in Breast Cancer Cells

Alin García-Miranda et al. Front Cell Dev Biol. .

Abstract

Autophagy is an intracellular recycling process active in eukaryotic cells that involves the formation of an autophagosome which delivers cytoplasmic components to the lysosome for degradation. This process occurs at low rates under basal conditions, but it can be induced by diverse types of stress such as starvation, hypoxia, metabolic disorders or in response to hormones, including leptin. Leptin is considered a pro-tumorigenic protein whose circulating levels have been related to bad prognosis in obese breast cancer patients. It has been recently demonstrated that leptin can induce autophagy in cancer cell lines from different tissues, suggesting that autophagy could modulate the pro-tumorigenic effects associated with leptin. In this study, the role of autophagy in leptin-induced proliferation, migration, apoptosis and ERK phosphorylation in breast cancer cell lines was evaluated. Although leptin differentially induced autophagy in the breast cancer cell lines tested, autophagy inhibition reduced leptin-induced cell proliferation in MCF7 cells and decreased cell migration, ERK activation, and impaired morphological changes in both cell lines. Our data demonstrates an important role for basal autophagy or leptin-induced autophagy in leptin-induced migration and ERK phosphorylation in breast cancer cell lines, suggesting a potential use for the inhibition of autophagy in breast cancer associated with obesity.

Keywords: ERK; autophagy; breast cancer; leptin; migration; proliferation.

PubMed Disclaimer

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Leptin differentially induced autophagy in breast cancer cells. (A,B) Breast cancer cell lines were treated with leptin for 24 h ± CQ for the last 2 h and changes in autophagy markers LC3II and p62 were assessed by western blot or EGFP-LC3 positive puncta per cell were evaluated for autophagosome formation. Increased autophagic flux induced by leptin was observed in MCF7 cells by western blot (A) and EGFP-LC3 puncta (C) but not in MDA-MB-231 (B,D). C, control treated with vehicle; L, leptin; CQ, chloroquine. Graphs show mean ± SEM; n = 4; p < 0.05. *vs. C; # vs. L; ϕ vs. CQ.
FIGURE 2
FIGURE 2
Autophagy contributes to leptin-induced proliferation in MCF7 but not in MDA-MB-231 cells. Cells were treated with leptin and/or CQ for 48 h. Leptin increased cell proliferation in MCF7 cells which was reduced by CQ treatment (A). Apoptosis was increased by CQ in MCF7 cells and this was partly prevented by leptin treatment (C). In MDA-MB-231 cells, leptin did not affect proliferation (B) and CQ treatment reduced proliferation (B) and increased apoptosis (D) independent of leptin treatment (E). Representative images of caspase activity monitoring by green florescence with a caspase 3/7 substrate. Mean ± SEM; n = 5; p < 0.05. *vs. C; # vs. L; ϕ vs. CQ.
FIGURE 3
FIGURE 3
Autophagy participates in leptin-induced ETM-related changes in morphology of MCF7 and MDA-MB-231 cells. (A) Representative images of morphological changes in breast cancer cells. (B,C) Leptin favors mesenchymal spindle-like morphology in both cell lines. Autophagy inhibition reduced leptin-induced changes in morphology in both cell types. Mean ± SEM; n = 3; p < 0.05. *vs. C; # vs. L; ϕ vs. CQ.
FIGURE 4
FIGURE 4
Autophagy contributes to leptin-induced migration in breast cancer cells. (A–D) Leptin increased cell migration and autophagy inhibition with CQ reduced leptin-induced migration (A,C), in MCF7 at 48 h (A) and MDA-MB-231 cells at 24 and 48 h (C). In both non-silencing cell lines, leptin increased the wound healing (B,D). In MCF7 cells, genetic inhibition of autophagy with an ATG7 shRNA (A7) reduced leptin-induced migration in comparison with non-silencing cells (NS) at 48 h (B) while in MDA-MB-231 cells, leptin-induced migration was reduced at 24 h (D). ATG7 shRNA similarly decreased the levels of ATG7 in both cell lines (E). Mean ± SEM; wound healing with CQ n = 5; p < 0.05. *vs. C; # vs. L; ϕ vs. CQ. Wound healing with NS and shATG7 n = 4 for MCF7 cells; n = 3 for MDA-MB-231. p < 0.05. *vs. NS; # vs. NS + L.
FIGURE 5
FIGURE 5
Autophagy inhibition decreased leptin-induced ERK activation in breast cancer cells. Leptin (L) induced ERK phosphorylation (A,B) in both cell lines. Autophagy inhibition with chloroquine (CQ) decreased leptin-induced ERK phosphorylation at 15 min. MEK inhibitor PD0325901 25 nM was used as a positive control. Mean ± SEM; n = 4; p < 0.05. *vs. C; # vs. L.

Similar articles

Cited by

References

    1. Ahima R. S., Osei S. Y. (2004). Leptin signaling. Physiol. Behav. 81 223–241. - PubMed
    1. Azad M. B., Chen Y., Gibson S. B. (2009). Regulation of autophagy by reactive oxygen species (ROS): implications for cancer progression and treatment. Antioxid Redox Signal 11 777–790. 10.1089/ars.2008.2270 - DOI - PubMed
    1. Carroll B., Mohd-Naim N., Maximiano F., Frasa M. A., Mccormack J., Finelli M., et al. (2013). The TBC/RabGAP Armus coordinates Rac1 and Rab7 functions during autophagy. Dev. Cell 25 15–28. 10.1016/j.devcel.2013.03.005 - DOI - PMC - PubMed
    1. Cirillo D., Rachiglio A. M., La Montagna R., Giordano A., Normanno N. (2008). Leptin signaling in breast cancer: an overview. J. Cell Biochem. 105 956–964. 10.1002/jcb.21911 - DOI - PubMed
    1. Cotzomi-Ortega I., Rosas-Cruz A., Ramirez-Ramirez D., Reyes-Leyva J., Rodriguez-Sosa M., Aguilar-Alonso P., et al. (2020). Autophagy inhibition induces the secretion of macrophage migration inhibitory factor (MIF) with autocrine and paracrine effects on the promotion of malignancy in breast cancer. Biology (Basel) 9:20. - PMC - PubMed
  NODES
twitter 2