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Leptin produced by obese adipose stromal/stem cells enhances proliferation and metastasis of estrogen receptor positive breast cancers.

Strong AL, Ohlstein JF, Biagas BA, Rhodes LV, Pei DT, Tucker HA, Llamas C, Bowles AC, Dutreil MF, Zhang S, Gimble JM, Burow ME, Bunnell BA - Breast Cancer Res. (2015)

Bottom Line: BCCs co-cultured with obASCs demonstrated enhanced expression of epithelial-to-mesenchymal transition (EMT) and metastasis genes (SERPINE1, MMP-2, and IL-6), while BCCs co-cultured with leptin shRNA obASCs did not display similar levels of gene induction.Knockdown of leptin significantly reduced tumor volume and decreased the number of metastatic lesions to the lung and liver.These results correlated with reduced expression of both SERPINE1 and MMP-2 in tumors formed with MCF7 cells mixed with leptin shRNA obASCs, when compared to tumors formed with MCF7 cells mixed with control shRNA obASCs.

View Article: PubMed Central - PubMed

Affiliation: Center for Stem Cell Research and Regenerative Medicine, Tulane University School of Medicine, 1430 Tulane Avenue, SL-99, New Orleans, LA, 70112, USA. alin1@tulane.edu.

ABSTRACT

Introduction: The steady increase in the incidence of obesity among adults has been paralleled with higher levels of obesity-associated breast cancer. While recent studies have suggested that adipose stromal/stem cells (ASCs) isolated from obese women enhance tumorigenicity, the mechanism(s) by which this occurs remains undefined. Evidence suggests that increased adiposity results in increased leptin secretion from adipose tissue, which has been shown to increased cancer cell proliferation. Previously, our group demonstrated that ASCs isolated from obese women (obASCs) also express higher levels of leptin relative to ASCs isolated from lean women (lnASCs) and that this obASC-derived leptin may account for enhanced breast cancer cell growth. The current study investigates the impact of inhibiting leptin expression in lnASCs and obASCs on breast cancer cell (BCC) growth and progression.

Methods: Estrogen receptor positive (ER+) BCCs were co-cultured with leptin shRNA lnASCs or leptin shRNA obASCs and changes in the proliferation, migration, invasion, and gene expression of BCCs were investigated. To assess the direct impact of leptin inhibition in obASCs on BCC proliferation, MCF7 cells were injected alone or mixed with control shRNA obASCs or leptin shRNA obASCs into SCID/beige mice.

Results: ER+ BCCs were responsive to obASCs during direct co-culture, whereas lnASCs were unable to increase ER(+) BCC growth. shRNA silencing of leptin in obASCs negated the enhanced proliferative effects of obASC on BCCs following direct co-culture. BCCs co-cultured with obASCs demonstrated enhanced expression of epithelial-to-mesenchymal transition (EMT) and metastasis genes (SERPINE1, MMP-2, and IL-6), while BCCs co-cultured with leptin shRNA obASCs did not display similar levels of gene induction. Knockdown of leptin significantly reduced tumor volume and decreased the number of metastatic lesions to the lung and liver. These results correlated with reduced expression of both SERPINE1 and MMP-2 in tumors formed with MCF7 cells mixed with leptin shRNA obASCs, when compared to tumors formed with MCF7 cells mixed with control shRNA obASCs.

Conclusion: This study provides mechanistic insight as to how obesity enhances the proliferation and metastasis of breast cancer cells; specifically, obASC-derived leptin contributes to the aggressiveness of breast cancer in obese women.

No MeSH data available.


Related in: MedlinePlus

Leptin is essential for the adipose stromal/stem cells isolated from obese women (obASC)-driven breast cancer cell (BCC) proliferation. Adipose stromal/stem cells isolated from lean women (lnASCs) and obASCs transfected with either a control short hairpin RNA (control-shRNA) or leptin shRNA were co-cultured (CC) with BCCs. After 7 days, the green fluorescent protein-positive (GFP+) BCCs were sorted by FACS and counted. Bar represents ± standard error of the mean. *P <0.05, ***P <0.001, relative to no co-culture; ##P <0.01, ###P <0.001 between BCCs co-cultured with control shRNA lnASCs and control shRNA obASCs; ΦΦΦP <0.001 for comparison between BCCs co-cultured with control shRNA obASCs and leptin shRNA obASCs
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Fig2: Leptin is essential for the adipose stromal/stem cells isolated from obese women (obASC)-driven breast cancer cell (BCC) proliferation. Adipose stromal/stem cells isolated from lean women (lnASCs) and obASCs transfected with either a control short hairpin RNA (control-shRNA) or leptin shRNA were co-cultured (CC) with BCCs. After 7 days, the green fluorescent protein-positive (GFP+) BCCs were sorted by FACS and counted. Bar represents ± standard error of the mean. *P <0.05, ***P <0.001, relative to no co-culture; ##P <0.01, ###P <0.001 between BCCs co-cultured with control shRNA lnASCs and control shRNA obASCs; ΦΦΦP <0.001 for comparison between BCCs co-cultured with control shRNA obASCs and leptin shRNA obASCs

Mentions: The direct role of leptin secreted from obASCs on BCC proliferation was investigated by co-culturing control shRNA lnASCs, leptin shRNA lnASCs, control shRNA obASCs, or leptin shRNA obASCs with BCCs at a 1:1 ratio. The proliferation of BCCs was compared to BCCs cultured alone. MCF7, ZR75, and T47D cells demonstrated an increase in the total cell number following co-culture with control shRNA obASCs compared to BCCs cultured alone or co-cultured with control lnASCs (P <0.05; Fig. 2). The obASCs transfected with the leptin shRNA were unable to induce proliferation of BCCs in comparison to the obASC expressing the control shRNA. Leptin shRNA obASCs reduced the extent of proliferation in MCF7, ZR75, and T47D from 1.3E6 cells to 0.5E6 cells (2.2-fold decrease), 1.2E6 cells to 0.3E6 cells (4.0-fold decrease), and 1.3E6 cells to 0.9E6 cells (1.4-fold decrease), respectively, comparing BCCs exposed to control shRNA obASCs to leptin shRNA obASCs (P <0.05; Fig. 2). To assess whether CM collected from ASCs was able to induce BCC proliferation, CM was collected from control shRNA lnASCs, leptin shRNA lnASCs, control shRNA obASCs, and leptin shRNA obASCs. BCCs incubated in control shRNA obASCs induced BCC proliferation by 1.4-fold in MCF7 cells, 1.8-fold in ZR75 cells, and 1.6-fold in T47D cells; however BCCs incubated in control shRNA lnASCs, leptin shRNA lnASCs, and leptin shRNA obASCs were unable to induce BCC proliferation. These results implicate obASC-derived leptin as a key factor leading to enhanced proliferation of BCCs.Fig. 2


Leptin produced by obese adipose stromal/stem cells enhances proliferation and metastasis of estrogen receptor positive breast cancers.

Strong AL, Ohlstein JF, Biagas BA, Rhodes LV, Pei DT, Tucker HA, Llamas C, Bowles AC, Dutreil MF, Zhang S, Gimble JM, Burow ME, Bunnell BA - Breast Cancer Res. (2015)

Leptin is essential for the adipose stromal/stem cells isolated from obese women (obASC)-driven breast cancer cell (BCC) proliferation. Adipose stromal/stem cells isolated from lean women (lnASCs) and obASCs transfected with either a control short hairpin RNA (control-shRNA) or leptin shRNA were co-cultured (CC) with BCCs. After 7 days, the green fluorescent protein-positive (GFP+) BCCs were sorted by FACS and counted. Bar represents ± standard error of the mean. *P <0.05, ***P <0.001, relative to no co-culture; ##P <0.01, ###P <0.001 between BCCs co-cultured with control shRNA lnASCs and control shRNA obASCs; ΦΦΦP <0.001 for comparison between BCCs co-cultured with control shRNA obASCs and leptin shRNA obASCs
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4541745&req=5

Fig2: Leptin is essential for the adipose stromal/stem cells isolated from obese women (obASC)-driven breast cancer cell (BCC) proliferation. Adipose stromal/stem cells isolated from lean women (lnASCs) and obASCs transfected with either a control short hairpin RNA (control-shRNA) or leptin shRNA were co-cultured (CC) with BCCs. After 7 days, the green fluorescent protein-positive (GFP+) BCCs were sorted by FACS and counted. Bar represents ± standard error of the mean. *P <0.05, ***P <0.001, relative to no co-culture; ##P <0.01, ###P <0.001 between BCCs co-cultured with control shRNA lnASCs and control shRNA obASCs; ΦΦΦP <0.001 for comparison between BCCs co-cultured with control shRNA obASCs and leptin shRNA obASCs
Mentions: The direct role of leptin secreted from obASCs on BCC proliferation was investigated by co-culturing control shRNA lnASCs, leptin shRNA lnASCs, control shRNA obASCs, or leptin shRNA obASCs with BCCs at a 1:1 ratio. The proliferation of BCCs was compared to BCCs cultured alone. MCF7, ZR75, and T47D cells demonstrated an increase in the total cell number following co-culture with control shRNA obASCs compared to BCCs cultured alone or co-cultured with control lnASCs (P <0.05; Fig. 2). The obASCs transfected with the leptin shRNA were unable to induce proliferation of BCCs in comparison to the obASC expressing the control shRNA. Leptin shRNA obASCs reduced the extent of proliferation in MCF7, ZR75, and T47D from 1.3E6 cells to 0.5E6 cells (2.2-fold decrease), 1.2E6 cells to 0.3E6 cells (4.0-fold decrease), and 1.3E6 cells to 0.9E6 cells (1.4-fold decrease), respectively, comparing BCCs exposed to control shRNA obASCs to leptin shRNA obASCs (P <0.05; Fig. 2). To assess whether CM collected from ASCs was able to induce BCC proliferation, CM was collected from control shRNA lnASCs, leptin shRNA lnASCs, control shRNA obASCs, and leptin shRNA obASCs. BCCs incubated in control shRNA obASCs induced BCC proliferation by 1.4-fold in MCF7 cells, 1.8-fold in ZR75 cells, and 1.6-fold in T47D cells; however BCCs incubated in control shRNA lnASCs, leptin shRNA lnASCs, and leptin shRNA obASCs were unable to induce BCC proliferation. These results implicate obASC-derived leptin as a key factor leading to enhanced proliferation of BCCs.Fig. 2

Bottom Line: BCCs co-cultured with obASCs demonstrated enhanced expression of epithelial-to-mesenchymal transition (EMT) and metastasis genes (SERPINE1, MMP-2, and IL-6), while BCCs co-cultured with leptin shRNA obASCs did not display similar levels of gene induction.Knockdown of leptin significantly reduced tumor volume and decreased the number of metastatic lesions to the lung and liver.These results correlated with reduced expression of both SERPINE1 and MMP-2 in tumors formed with MCF7 cells mixed with leptin shRNA obASCs, when compared to tumors formed with MCF7 cells mixed with control shRNA obASCs.

View Article: PubMed Central - PubMed

Affiliation: Center for Stem Cell Research and Regenerative Medicine, Tulane University School of Medicine, 1430 Tulane Avenue, SL-99, New Orleans, LA, 70112, USA. alin1@tulane.edu.

ABSTRACT

Introduction: The steady increase in the incidence of obesity among adults has been paralleled with higher levels of obesity-associated breast cancer. While recent studies have suggested that adipose stromal/stem cells (ASCs) isolated from obese women enhance tumorigenicity, the mechanism(s) by which this occurs remains undefined. Evidence suggests that increased adiposity results in increased leptin secretion from adipose tissue, which has been shown to increased cancer cell proliferation. Previously, our group demonstrated that ASCs isolated from obese women (obASCs) also express higher levels of leptin relative to ASCs isolated from lean women (lnASCs) and that this obASC-derived leptin may account for enhanced breast cancer cell growth. The current study investigates the impact of inhibiting leptin expression in lnASCs and obASCs on breast cancer cell (BCC) growth and progression.

Methods: Estrogen receptor positive (ER+) BCCs were co-cultured with leptin shRNA lnASCs or leptin shRNA obASCs and changes in the proliferation, migration, invasion, and gene expression of BCCs were investigated. To assess the direct impact of leptin inhibition in obASCs on BCC proliferation, MCF7 cells were injected alone or mixed with control shRNA obASCs or leptin shRNA obASCs into SCID/beige mice.

Results: ER+ BCCs were responsive to obASCs during direct co-culture, whereas lnASCs were unable to increase ER(+) BCC growth. shRNA silencing of leptin in obASCs negated the enhanced proliferative effects of obASC on BCCs following direct co-culture. BCCs co-cultured with obASCs demonstrated enhanced expression of epithelial-to-mesenchymal transition (EMT) and metastasis genes (SERPINE1, MMP-2, and IL-6), while BCCs co-cultured with leptin shRNA obASCs did not display similar levels of gene induction. Knockdown of leptin significantly reduced tumor volume and decreased the number of metastatic lesions to the lung and liver. These results correlated with reduced expression of both SERPINE1 and MMP-2 in tumors formed with MCF7 cells mixed with leptin shRNA obASCs, when compared to tumors formed with MCF7 cells mixed with control shRNA obASCs.

Conclusion: This study provides mechanistic insight as to how obesity enhances the proliferation and metastasis of breast cancer cells; specifically, obASC-derived leptin contributes to the aggressiveness of breast cancer in obese women.

No MeSH data available.


Related in: MedlinePlus