Limits...
Exposure of tumor-associated macrophages to apoptotic MCF-7 cells promotes breast cancer growth and metastasis.

Zhou N, Zhang Y, Zhang X, Lei Z, Hu R, Li H, Mao Y, Wang X, Irwin DM, Niu G, Tan H - Int J Mol Sci (2015)

Bottom Line: Tumor-associated macrophages (TAMs) have been found to be associated with the progression and metastasis of breast cancer.Macrophages co-cultured with apoptotic MCF-7 had increased tumor growth and metastatic ability in a nude mouse transplantation assay.During this process, macrophages secreted increased amounts of interleukin 6 (IL-6) leading to increased phosphorylation of signal transducers and activators of transcription 3 (STAT3), which likely explains the increased transcription of STAT3 target genes such as TGF-β1 and HIF-1α.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Peking University, Health Science Center, Beijing 100191, China. zhouna@bjmu.edu.cn.

ABSTRACT
Tumor-associated macrophages (TAMs) have been found to be associated with the progression and metastasis of breast cancer. To clarify the mechanisms underlying the crosstalk between TAMs and cancer stem cells (CSCs) in breast cancer recurrence and metastasis, we used a co-culture model of macrophages and apoptotic human breast cancer cell line MCF-7 cells to investigate the effects of TAMs on MCF-7 in vitro and in vivo. Macrophages co-cultured with apoptotic MCF-7 had increased tumor growth and metastatic ability in a nude mouse transplantation assay. The macrophages exposed to apoptotic cells also induce an increase in the proportion of CD44+/CD24- cancer stem-like cells, as well as their proliferative ability accompanied with an increase in mucin1 (MUC1) expression. During this process, macrophages secreted increased amounts of interleukin 6 (IL-6) leading to increased phosphorylation of signal transducers and activators of transcription 3 (STAT3), which likely explains the increased transcription of STAT3 target genes such as TGF-β1 and HIF-1α. Our results indicate that when cancer cells endure chemotherapy induced apoptosis, macrophages in their microenvironment can then activate cancer stem cells to promote cancer growth and metastasis by secreting IL-6, which activates STAT3 phosphorylation to regulate the transcription of its downstream target genes.

No MeSH data available.


Related in: MedlinePlus

In vivo tumorigenicity and metastatic assay. (A) Growth curves for tumors generated by MCF-7 cells grown in three types of conditioned media. The width and diameter of each tumor were measured using calipers, and tumor volume was calculated using the formula ½ × a × b2, where “a” is the longer tumor axis and “b” is the shorter tumor axis; (B) Tumor weight was measured after excising from mice, n = 5; (C) Images of tumors from the three groups of mice; (D) Macroscopic view of nodules in the lungs from the three groups of mice; (E,F) Quantification of the metastatic nodules in the three groups of mice (n = 5); (G,H) Hematoxylin-eosin (HE) staining of paraffin sections from livers and the lungs of the three groups of mice. Metastases are indicated by the black arrows. **p < 0.01, ***p < 0.001 vs. Normal media group; ###p < 0.001 vs. Mac group.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4490423&req=5

ijms-16-11966-f002: In vivo tumorigenicity and metastatic assay. (A) Growth curves for tumors generated by MCF-7 cells grown in three types of conditioned media. The width and diameter of each tumor were measured using calipers, and tumor volume was calculated using the formula ½ × a × b2, where “a” is the longer tumor axis and “b” is the shorter tumor axis; (B) Tumor weight was measured after excising from mice, n = 5; (C) Images of tumors from the three groups of mice; (D) Macroscopic view of nodules in the lungs from the three groups of mice; (E,F) Quantification of the metastatic nodules in the three groups of mice (n = 5); (G,H) Hematoxylin-eosin (HE) staining of paraffin sections from livers and the lungs of the three groups of mice. Metastases are indicated by the black arrows. **p < 0.01, ***p < 0.001 vs. Normal media group; ###p < 0.001 vs. Mac group.

Mentions: To determine whether change in the proportion of CD44+/CD24− cells induced by the co-culture of macrophages with apoptotic MCF-7 cells influence the malignancy of these cancer cells we tested the tumorigenicity of the MCF-7 cells exposed to the conditioned media using the nude mice model. MCF-7 cells cultured in normal media (i.e., not conditioned) are capable of forming neoplasm by two weeks after subcutaneous injection, although they grow at a slow rate (Figure 2A). Macrophage conditioned media (Mac group) did not significantly change the growth rate of the neoplasm, however, MCF-7 cells exposed to conditioned media from macrophages grown with apoptotic MCF-7 cells (CoA group) grew at a significantly higher rate (Figure 2A). As expected, tumors from the CoA group were larger and heavier than those from the other two groups, with no difference in the tumor size or weight seen between the normal media and the Mac groups (Figure 2B,C). To further examine the metastatic properties of these cells we used the experimental metastatic model to examine the numbers of metastases formed in the liver and the lung. Visible and microscopic metastases were observed in both the normal media and the CoA groups but not in the Mac group (Figure 2D,G,H). When metastatic growths in the liver and the lung were examined, a very high number of foci were observed on the surface of liver and the lung in the CoA group, which was significantly higher than that seen in the Mac group (Figure 2E,F). These results suggest that the macrophage co-culture with apoptotic MCF-7 cells yields a conditioned media that not only promotes tumor growth in vivo, but also increases metastatic ability of the MCF-7 cells, whereas conditioned media from a macrophage culture alone inhibits tumor metastasis in vivo.


Exposure of tumor-associated macrophages to apoptotic MCF-7 cells promotes breast cancer growth and metastasis.

Zhou N, Zhang Y, Zhang X, Lei Z, Hu R, Li H, Mao Y, Wang X, Irwin DM, Niu G, Tan H - Int J Mol Sci (2015)

In vivo tumorigenicity and metastatic assay. (A) Growth curves for tumors generated by MCF-7 cells grown in three types of conditioned media. The width and diameter of each tumor were measured using calipers, and tumor volume was calculated using the formula ½ × a × b2, where “a” is the longer tumor axis and “b” is the shorter tumor axis; (B) Tumor weight was measured after excising from mice, n = 5; (C) Images of tumors from the three groups of mice; (D) Macroscopic view of nodules in the lungs from the three groups of mice; (E,F) Quantification of the metastatic nodules in the three groups of mice (n = 5); (G,H) Hematoxylin-eosin (HE) staining of paraffin sections from livers and the lungs of the three groups of mice. Metastases are indicated by the black arrows. **p < 0.01, ***p < 0.001 vs. Normal media group; ###p < 0.001 vs. Mac group.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490423&req=5

ijms-16-11966-f002: In vivo tumorigenicity and metastatic assay. (A) Growth curves for tumors generated by MCF-7 cells grown in three types of conditioned media. The width and diameter of each tumor were measured using calipers, and tumor volume was calculated using the formula ½ × a × b2, where “a” is the longer tumor axis and “b” is the shorter tumor axis; (B) Tumor weight was measured after excising from mice, n = 5; (C) Images of tumors from the three groups of mice; (D) Macroscopic view of nodules in the lungs from the three groups of mice; (E,F) Quantification of the metastatic nodules in the three groups of mice (n = 5); (G,H) Hematoxylin-eosin (HE) staining of paraffin sections from livers and the lungs of the three groups of mice. Metastases are indicated by the black arrows. **p < 0.01, ***p < 0.001 vs. Normal media group; ###p < 0.001 vs. Mac group.
Mentions: To determine whether change in the proportion of CD44+/CD24− cells induced by the co-culture of macrophages with apoptotic MCF-7 cells influence the malignancy of these cancer cells we tested the tumorigenicity of the MCF-7 cells exposed to the conditioned media using the nude mice model. MCF-7 cells cultured in normal media (i.e., not conditioned) are capable of forming neoplasm by two weeks after subcutaneous injection, although they grow at a slow rate (Figure 2A). Macrophage conditioned media (Mac group) did not significantly change the growth rate of the neoplasm, however, MCF-7 cells exposed to conditioned media from macrophages grown with apoptotic MCF-7 cells (CoA group) grew at a significantly higher rate (Figure 2A). As expected, tumors from the CoA group were larger and heavier than those from the other two groups, with no difference in the tumor size or weight seen between the normal media and the Mac groups (Figure 2B,C). To further examine the metastatic properties of these cells we used the experimental metastatic model to examine the numbers of metastases formed in the liver and the lung. Visible and microscopic metastases were observed in both the normal media and the CoA groups but not in the Mac group (Figure 2D,G,H). When metastatic growths in the liver and the lung were examined, a very high number of foci were observed on the surface of liver and the lung in the CoA group, which was significantly higher than that seen in the Mac group (Figure 2E,F). These results suggest that the macrophage co-culture with apoptotic MCF-7 cells yields a conditioned media that not only promotes tumor growth in vivo, but also increases metastatic ability of the MCF-7 cells, whereas conditioned media from a macrophage culture alone inhibits tumor metastasis in vivo.

Bottom Line: Tumor-associated macrophages (TAMs) have been found to be associated with the progression and metastasis of breast cancer.Macrophages co-cultured with apoptotic MCF-7 had increased tumor growth and metastatic ability in a nude mouse transplantation assay.During this process, macrophages secreted increased amounts of interleukin 6 (IL-6) leading to increased phosphorylation of signal transducers and activators of transcription 3 (STAT3), which likely explains the increased transcription of STAT3 target genes such as TGF-β1 and HIF-1α.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Peking University, Health Science Center, Beijing 100191, China. zhouna@bjmu.edu.cn.

ABSTRACT
Tumor-associated macrophages (TAMs) have been found to be associated with the progression and metastasis of breast cancer. To clarify the mechanisms underlying the crosstalk between TAMs and cancer stem cells (CSCs) in breast cancer recurrence and metastasis, we used a co-culture model of macrophages and apoptotic human breast cancer cell line MCF-7 cells to investigate the effects of TAMs on MCF-7 in vitro and in vivo. Macrophages co-cultured with apoptotic MCF-7 had increased tumor growth and metastatic ability in a nude mouse transplantation assay. The macrophages exposed to apoptotic cells also induce an increase in the proportion of CD44+/CD24- cancer stem-like cells, as well as their proliferative ability accompanied with an increase in mucin1 (MUC1) expression. During this process, macrophages secreted increased amounts of interleukin 6 (IL-6) leading to increased phosphorylation of signal transducers and activators of transcription 3 (STAT3), which likely explains the increased transcription of STAT3 target genes such as TGF-β1 and HIF-1α. Our results indicate that when cancer cells endure chemotherapy induced apoptosis, macrophages in their microenvironment can then activate cancer stem cells to promote cancer growth and metastasis by secreting IL-6, which activates STAT3 phosphorylation to regulate the transcription of its downstream target genes.

No MeSH data available.


Related in: MedlinePlus