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Src/STAT3-dependent heme oxygenase-1 induction mediates chemoresistance of breast cancer cells to doxorubicin by promoting autophagy.

Tan Q, Wang H, Hu Y, Hu M, Li X - Cancer Sci. (2015)

Bottom Line: In the present study, we found an induction of HO-1 expression in doxorubicin (DOX)-treated MDA-MB-231 human breast adenocarcinoma cells, which showed insensitivity to DOX treatment.Knockdown HO-1 expression dramatically upregulated the incidence of MDA-MB-231 cell death under DOX treatment, indicating that HO-1 functions as a critical contributor to drug resistance in MDA-MB-231 cells.Moreover, upregulation of HO-1 expression required the activation of both signal transducer and activator of transcription (STAT)3 and its upstream regulator, protein kinase Src.

View Article: PubMed Central - PubMed

Affiliation: Department of Stress Medicine, Beijing Institute of Basic Medical Sciences, Beijing, China.

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Src was the upstream protein kinase responsible for STAT3 activation under doxorubicin (DOX) treatment. (a) MDA-MB-231 and MDA-MB-453 cells were treated with DOX (0.2 μM) for the indicated time periods and then the induction of Src activation was detected by western-blot assay. (b) MDA-MB-231 cells were co-transfected with STAT3-dependent luciferase reporter plasmid and Src siRNA and then exposed to DOX (0.2 μM) 36 h after transfection. Then the induction of STAT3 luciferase activities was determined at the indicated time periods after DOX treatment. (c) MDA-MB-231 cells were transfected with Src siRNA or control siRNA and then treated with DOX (0.2 μM) 36 h after transfection. Then the activation of STAT3 and the expressions of heme oxygenase-1 (HO-1), Beclin-1 and LC3BI/II were determined 12 h after DOX exposure. To avoid the off-target effect, two different siRNA against Src were purchased and tested. Data shown here were obtained from the most effective one. (d,e) MDA-MB-231 cells were transfected and treated as described in figure (c) and then autophagy was detected as described in Figure3(b,c). (f) MDA-MB-231 cells were transfected and treated as described in figure (c) and then cell death incidence was detected 48 h after DOX treatment.
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fig05: Src was the upstream protein kinase responsible for STAT3 activation under doxorubicin (DOX) treatment. (a) MDA-MB-231 and MDA-MB-453 cells were treated with DOX (0.2 μM) for the indicated time periods and then the induction of Src activation was detected by western-blot assay. (b) MDA-MB-231 cells were co-transfected with STAT3-dependent luciferase reporter plasmid and Src siRNA and then exposed to DOX (0.2 μM) 36 h after transfection. Then the induction of STAT3 luciferase activities was determined at the indicated time periods after DOX treatment. (c) MDA-MB-231 cells were transfected with Src siRNA or control siRNA and then treated with DOX (0.2 μM) 36 h after transfection. Then the activation of STAT3 and the expressions of heme oxygenase-1 (HO-1), Beclin-1 and LC3BI/II were determined 12 h after DOX exposure. To avoid the off-target effect, two different siRNA against Src were purchased and tested. Data shown here were obtained from the most effective one. (d,e) MDA-MB-231 cells were transfected and treated as described in figure (c) and then autophagy was detected as described in Figure3(b,c). (f) MDA-MB-231 cells were transfected and treated as described in figure (c) and then cell death incidence was detected 48 h after DOX treatment.

Mentions: Both JAK2 and Src kinases are well-known cytoplasmic tyrosine kinases that are responsible for phosphorylating and activating STAT3.30,31 Therefore, to determine the upstream signal molecules leading to STAT3 activation in MDA-MB-231 cells under DOX exposure, we next detected the activation status of Src and JAK2 in the DOX-treated MDA-MB-231 and MDA-MB-453 cells. As shown in Figure5(a), after treatment with DOX, phosphorylation of Src was only significantly induced in MDA-MB-231 cells, but not in MDA-MB-453 cells. No signal of JAK2 activation was detected in either MDA-MB-231 or MDA-MB-453 cells under the same DOX exposure conditions (data not show).


Src/STAT3-dependent heme oxygenase-1 induction mediates chemoresistance of breast cancer cells to doxorubicin by promoting autophagy.

Tan Q, Wang H, Hu Y, Hu M, Li X - Cancer Sci. (2015)

Src was the upstream protein kinase responsible for STAT3 activation under doxorubicin (DOX) treatment. (a) MDA-MB-231 and MDA-MB-453 cells were treated with DOX (0.2 μM) for the indicated time periods and then the induction of Src activation was detected by western-blot assay. (b) MDA-MB-231 cells were co-transfected with STAT3-dependent luciferase reporter plasmid and Src siRNA and then exposed to DOX (0.2 μM) 36 h after transfection. Then the induction of STAT3 luciferase activities was determined at the indicated time periods after DOX treatment. (c) MDA-MB-231 cells were transfected with Src siRNA or control siRNA and then treated with DOX (0.2 μM) 36 h after transfection. Then the activation of STAT3 and the expressions of heme oxygenase-1 (HO-1), Beclin-1 and LC3BI/II were determined 12 h after DOX exposure. To avoid the off-target effect, two different siRNA against Src were purchased and tested. Data shown here were obtained from the most effective one. (d,e) MDA-MB-231 cells were transfected and treated as described in figure (c) and then autophagy was detected as described in Figure3(b,c). (f) MDA-MB-231 cells were transfected and treated as described in figure (c) and then cell death incidence was detected 48 h after DOX treatment.
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Related In: Results  -  Collection

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fig05: Src was the upstream protein kinase responsible for STAT3 activation under doxorubicin (DOX) treatment. (a) MDA-MB-231 and MDA-MB-453 cells were treated with DOX (0.2 μM) for the indicated time periods and then the induction of Src activation was detected by western-blot assay. (b) MDA-MB-231 cells were co-transfected with STAT3-dependent luciferase reporter plasmid and Src siRNA and then exposed to DOX (0.2 μM) 36 h after transfection. Then the induction of STAT3 luciferase activities was determined at the indicated time periods after DOX treatment. (c) MDA-MB-231 cells were transfected with Src siRNA or control siRNA and then treated with DOX (0.2 μM) 36 h after transfection. Then the activation of STAT3 and the expressions of heme oxygenase-1 (HO-1), Beclin-1 and LC3BI/II were determined 12 h after DOX exposure. To avoid the off-target effect, two different siRNA against Src were purchased and tested. Data shown here were obtained from the most effective one. (d,e) MDA-MB-231 cells were transfected and treated as described in figure (c) and then autophagy was detected as described in Figure3(b,c). (f) MDA-MB-231 cells were transfected and treated as described in figure (c) and then cell death incidence was detected 48 h after DOX treatment.
Mentions: Both JAK2 and Src kinases are well-known cytoplasmic tyrosine kinases that are responsible for phosphorylating and activating STAT3.30,31 Therefore, to determine the upstream signal molecules leading to STAT3 activation in MDA-MB-231 cells under DOX exposure, we next detected the activation status of Src and JAK2 in the DOX-treated MDA-MB-231 and MDA-MB-453 cells. As shown in Figure5(a), after treatment with DOX, phosphorylation of Src was only significantly induced in MDA-MB-231 cells, but not in MDA-MB-453 cells. No signal of JAK2 activation was detected in either MDA-MB-231 or MDA-MB-453 cells under the same DOX exposure conditions (data not show).

Bottom Line: In the present study, we found an induction of HO-1 expression in doxorubicin (DOX)-treated MDA-MB-231 human breast adenocarcinoma cells, which showed insensitivity to DOX treatment.Knockdown HO-1 expression dramatically upregulated the incidence of MDA-MB-231 cell death under DOX treatment, indicating that HO-1 functions as a critical contributor to drug resistance in MDA-MB-231 cells.Moreover, upregulation of HO-1 expression required the activation of both signal transducer and activator of transcription (STAT)3 and its upstream regulator, protein kinase Src.

View Article: PubMed Central - PubMed

Affiliation: Department of Stress Medicine, Beijing Institute of Basic Medical Sciences, Beijing, China.

Show MeSH
Related in: MedlinePlus