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Metformin exerts anticancer effects through the inhibition of the Sonic hedgehog signaling pathway in breast cancer.

Fan C, Wang Y, Liu Z, Sun Y, Wang X, Wei G, Wei J - Int. J. Mol. Med. (2015)

Bottom Line: Its anticancer effects, which are mediated by the activation of AMP-activated protein kinase (AMPK), have become notable.The aim of the present study was to elucidate the role of the Shh pathway in mediating the anticancer effects of metformin and the correlation between AMPK and the Shh pathway.Furthermore, the small interfering RNA (siRNA)‑mediated downregulation of AMPK reversed the inhibitory effects of metformin on rhShh‑induced Gli-1 expression and stemness.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemotherapy, Cancer Center, Qilu Hospital, Shandong University, Jinan, Shandong 250012, P.R. China.

ABSTRACT
Metformin, a widely prescribed antidiabetic drug, has previously been shown to lower the risk of certain types of cancer, including that of breast cancer, and to improve prognosis. Its anticancer effects, which are mediated by the activation of AMP-activated protein kinase (AMPK), have become notable. The Sonic hedgehog (Shh) signaling pathway is involved in changes in mammary ducts and malignant transformation. The aim of the present study was to elucidate the role of the Shh pathway in mediating the anticancer effects of metformin and the correlation between AMPK and the Shh pathway. We investigated the effectiveness of metformin in inhibiting the proliferation, migration, invasion and stemness of breast cancer cells in vitro using RNA extraction and reverse transcription‑polymerase chain reaction (RT-PCR), western blot analysis, cell proliferation assay, scratch-wound assay (cell migration assay), cell invasion assay, mammosphere culture and flow cytometry. In in vivo experiments, a tumor xenograft model was used to detect the effects of metformin on cancer cell proliferation. The results revealed that the treatment of breast cancer cells with metformin led to the inhibition of the Shh signaling pathway. Importantly, metformin inhibited recombinant human Shh (rhShh)‑induced cell migration, invasion, and stemness, and impaired cell proliferation both in vitro and in vivo. Furthermore, the small interfering RNA (siRNA)‑mediated downregulation of AMPK reversed the inhibitory effects of metformin on rhShh‑induced Gli-1 expression and stemness. Our findings identified a role of the Shh signaling pathway in the anticancer effects of metformin in breast cancer. Furthermore, we revealed that the metformin-mediated inhibition of the Shh signaling pathway may be dependent on AMPK.

No MeSH data available.


Related in: MedlinePlus

Metformin inhibits the recombinant human Sonic hedgehog (rhShh)-induced proliferation of breast cancer cells. (A and B) MTT assay of MDA-MB-231 and MCF-7 cells was conducted at 0, 12, 24, 48 and 72 h. All data represent the means ± SD of 3 separate experiments performed in triplicate. **P<0.01 vs. the control (Ctr) group, ##P<0.01 vs. the rhShh group. (C and D) Colony formation assays of MDA-MB-231 and MCF-7 cells. The number of colonies was counted under a microscope. **P<0.01 vs. the Ctr group; ##P<0.01 vs. the rhShh group.
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f3-ijmm-36-01-0204: Metformin inhibits the recombinant human Sonic hedgehog (rhShh)-induced proliferation of breast cancer cells. (A and B) MTT assay of MDA-MB-231 and MCF-7 cells was conducted at 0, 12, 24, 48 and 72 h. All data represent the means ± SD of 3 separate experiments performed in triplicate. **P<0.01 vs. the control (Ctr) group, ##P<0.01 vs. the rhShh group. (C and D) Colony formation assays of MDA-MB-231 and MCF-7 cells. The number of colonies was counted under a microscope. **P<0.01 vs. the Ctr group; ##P<0.01 vs. the rhShh group.

Mentions: To determine whether the suppression of Shh signaling by metformin contributes to the anticancer effects of the latter, we treated the cells with rhShh, a specific activator of the Shh signaling pathway. The effect of rhShh, metformin and rhShh combined with metformin on the proliferation of MCF-7 and MDA-MB-231 breast cancer cells was assessed by MTT assay. Treatment with 1 µg/ml of rhShh increased the proliferation of these cells in a time-dependent manner, while treatment with metformin significantly decreased the growth of MDA-MB-231 and MCF-7 cells at 48 and 72 h after treatment (P<0.01 compared to control; Fig. 3A and B). We also found that treatment with 3 mM of metformin inhibited the effect of rhShh in both the MDA-MB-231 and MCF-7 cells, with a statistically significant difference identified at 72 h (P<0.01 compared to rhShh treatment; Fig. 3A and B). The proliferative potential of the breast cancer cells under the same conditions was also assessed by a colony formation assay. Incubation with metformin resulted in a significant decrease in both the number and size of colonies compared with the control group. In agreement with the results obtained by MTT assay, treatment with 3 mM of metformin inhibited the increase in the number and size of the colonies induced by rhShh when compared to treatment with rhShh alone (Fig. 3C and D).


Metformin exerts anticancer effects through the inhibition of the Sonic hedgehog signaling pathway in breast cancer.

Fan C, Wang Y, Liu Z, Sun Y, Wang X, Wei G, Wei J - Int. J. Mol. Med. (2015)

Metformin inhibits the recombinant human Sonic hedgehog (rhShh)-induced proliferation of breast cancer cells. (A and B) MTT assay of MDA-MB-231 and MCF-7 cells was conducted at 0, 12, 24, 48 and 72 h. All data represent the means ± SD of 3 separate experiments performed in triplicate. **P<0.01 vs. the control (Ctr) group, ##P<0.01 vs. the rhShh group. (C and D) Colony formation assays of MDA-MB-231 and MCF-7 cells. The number of colonies was counted under a microscope. **P<0.01 vs. the Ctr group; ##P<0.01 vs. the rhShh group.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494591&req=5

f3-ijmm-36-01-0204: Metformin inhibits the recombinant human Sonic hedgehog (rhShh)-induced proliferation of breast cancer cells. (A and B) MTT assay of MDA-MB-231 and MCF-7 cells was conducted at 0, 12, 24, 48 and 72 h. All data represent the means ± SD of 3 separate experiments performed in triplicate. **P<0.01 vs. the control (Ctr) group, ##P<0.01 vs. the rhShh group. (C and D) Colony formation assays of MDA-MB-231 and MCF-7 cells. The number of colonies was counted under a microscope. **P<0.01 vs. the Ctr group; ##P<0.01 vs. the rhShh group.
Mentions: To determine whether the suppression of Shh signaling by metformin contributes to the anticancer effects of the latter, we treated the cells with rhShh, a specific activator of the Shh signaling pathway. The effect of rhShh, metformin and rhShh combined with metformin on the proliferation of MCF-7 and MDA-MB-231 breast cancer cells was assessed by MTT assay. Treatment with 1 µg/ml of rhShh increased the proliferation of these cells in a time-dependent manner, while treatment with metformin significantly decreased the growth of MDA-MB-231 and MCF-7 cells at 48 and 72 h after treatment (P<0.01 compared to control; Fig. 3A and B). We also found that treatment with 3 mM of metformin inhibited the effect of rhShh in both the MDA-MB-231 and MCF-7 cells, with a statistically significant difference identified at 72 h (P<0.01 compared to rhShh treatment; Fig. 3A and B). The proliferative potential of the breast cancer cells under the same conditions was also assessed by a colony formation assay. Incubation with metformin resulted in a significant decrease in both the number and size of colonies compared with the control group. In agreement with the results obtained by MTT assay, treatment with 3 mM of metformin inhibited the increase in the number and size of the colonies induced by rhShh when compared to treatment with rhShh alone (Fig. 3C and D).

Bottom Line: Its anticancer effects, which are mediated by the activation of AMP-activated protein kinase (AMPK), have become notable.The aim of the present study was to elucidate the role of the Shh pathway in mediating the anticancer effects of metformin and the correlation between AMPK and the Shh pathway.Furthermore, the small interfering RNA (siRNA)‑mediated downregulation of AMPK reversed the inhibitory effects of metformin on rhShh‑induced Gli-1 expression and stemness.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemotherapy, Cancer Center, Qilu Hospital, Shandong University, Jinan, Shandong 250012, P.R. China.

ABSTRACT
Metformin, a widely prescribed antidiabetic drug, has previously been shown to lower the risk of certain types of cancer, including that of breast cancer, and to improve prognosis. Its anticancer effects, which are mediated by the activation of AMP-activated protein kinase (AMPK), have become notable. The Sonic hedgehog (Shh) signaling pathway is involved in changes in mammary ducts and malignant transformation. The aim of the present study was to elucidate the role of the Shh pathway in mediating the anticancer effects of metformin and the correlation between AMPK and the Shh pathway. We investigated the effectiveness of metformin in inhibiting the proliferation, migration, invasion and stemness of breast cancer cells in vitro using RNA extraction and reverse transcription‑polymerase chain reaction (RT-PCR), western blot analysis, cell proliferation assay, scratch-wound assay (cell migration assay), cell invasion assay, mammosphere culture and flow cytometry. In in vivo experiments, a tumor xenograft model was used to detect the effects of metformin on cancer cell proliferation. The results revealed that the treatment of breast cancer cells with metformin led to the inhibition of the Shh signaling pathway. Importantly, metformin inhibited recombinant human Shh (rhShh)‑induced cell migration, invasion, and stemness, and impaired cell proliferation both in vitro and in vivo. Furthermore, the small interfering RNA (siRNA)‑mediated downregulation of AMPK reversed the inhibitory effects of metformin on rhShh‑induced Gli-1 expression and stemness. Our findings identified a role of the Shh signaling pathway in the anticancer effects of metformin in breast cancer. Furthermore, we revealed that the metformin-mediated inhibition of the Shh signaling pathway may be dependent on AMPK.

No MeSH data available.


Related in: MedlinePlus