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Molecular signature of response and potential pathways related to resistance to the HSP90 inhibitor, 17AAG, in breast cancer.

Zajac M, Gomez G, Benitez J, Martínez-Delgado B - BMC Med Genomics (2010)

Bottom Line: In addition, different patterns of HSP90 client transcriptional changes after 17AAG were identified associated to the sensitive cell lines, which could be useful to evaluate drug effectiveness.Finally, we have found differentially expressed pathways associated to resistance to 17AAG.Our study shows that global mRNA expression analysis is a useful strategy to examine molecular effects of drugs, which allowed us the discovery of new biomarkers of 17AAG activity and provided more insights into the complex mechanism of 17AAG resistance.

View Article: PubMed Central - HTML - PubMed

Affiliation: Human Genetics Group, Spanish National Cancer Centre, Madrid, Spain.

ABSTRACT

Background: HSP90 may be a favorable target for investigational therapy in breast cancer. In fact, the HSP90 inhibitor, 17AAG, currently has entered in phase II clinical trials as an anticancer agent in breast and other tumors. Since HSP90 inhibition leads to global depletion of oncogenic proteins involved in multiple pathways we applied global analysis using gene array technology to study new genes and pathways involved in the drug response in breast cancer.

Methods: Gene expression profiling using Whole Human Genome Agilent array technology was applied to a total of six sensitive and two resistant breast cancer cell lines pre-treatment and treated with the 17AAG for 24 and 48 hours.

Results: We have identified a common molecular signature of response to 17AAG composed of 35 genes which include novel pharmacodynamic markers of this drug. In addition, different patterns of HSP90 client transcriptional changes after 17AAG were identified associated to the sensitive cell lines, which could be useful to evaluate drug effectiveness. Finally, we have found differentially expressed pathways associated to resistance to 17AAG. We observed significant activation of NF-κB and MAPK pathways in resistant cells upon treatment, indicating that these pathways could be potentially targeted to overcome resistance.

Conclusions: Our study shows that global mRNA expression analysis is a useful strategy to examine molecular effects of drugs, which allowed us the discovery of new biomarkers of 17AAG activity and provided more insights into the complex mechanism of 17AAG resistance.

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Related in: MedlinePlus

Differential signaling pathway activation in resistant and sensitive breast cancer cells upon treatment with 17AAG. Transfections were carried out in the sensitive (MCF-7 and Hs578T) and resistant (MDA MB 231 and T47D), cells with the reporter constructs for the typical cancer biology pathways: NOTCH, WNT, TGFβ, P53, cell cycle, MYC/MAX, NF-κB, MAPK/ERK, MAPK/JNK and HIF, followed by 17AAG or DMSO treatment. Dual-luciferase assay was performed, and promoter activity values are expressed as arbitrary units using a Renilla reporter for internal normalization. The experiment performed itself in triplicates was repeated at least twice of each cell line studied. The error bars represent standard deviation. Pathways significantly (p-value < 0.05) repressed or activated are marked with a star.
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Figure 5: Differential signaling pathway activation in resistant and sensitive breast cancer cells upon treatment with 17AAG. Transfections were carried out in the sensitive (MCF-7 and Hs578T) and resistant (MDA MB 231 and T47D), cells with the reporter constructs for the typical cancer biology pathways: NOTCH, WNT, TGFβ, P53, cell cycle, MYC/MAX, NF-κB, MAPK/ERK, MAPK/JNK and HIF, followed by 17AAG or DMSO treatment. Dual-luciferase assay was performed, and promoter activity values are expressed as arbitrary units using a Renilla reporter for internal normalization. The experiment performed itself in triplicates was repeated at least twice of each cell line studied. The error bars represent standard deviation. Pathways significantly (p-value < 0.05) repressed or activated are marked with a star.

Mentions: Interestingly, the results revealed that NF-κB and MAPK/JNK pathway were found significantly activated in both resistant compared to the sensitive cell lines (Figure 5). Although below statistical significance, GSEA revealed NF-κB as one of the most relevant pathways associated to 17AAG resistance. The increased activity of the NF-κB, may indicate that this pathway plays an important role in cell survival upon treatment. Additionally, MAPK pathways could have also some role in the resistance to 17AAG, as MAPK/JNK was significantly activated in both resistant T47 D and MDA-MB-231 cell lines, and the MAPK/ERK was induced in T47 D. Cell cycle pathway was significantly activated only in MDA-MB-231 resistant cell line, what may reflect the higher proliferation status of these cells. Sensitive MCF-7 cells showed a critical reduction in the activity of all of the pathways, which correlate with the stop in proliferation and death induced after the treatment (Figure 5). The other sensitive cell line, Hs578T also showed inhibition of most of the pathways except NOTCH, TGF and Hypoxia pathway.


Molecular signature of response and potential pathways related to resistance to the HSP90 inhibitor, 17AAG, in breast cancer.

Zajac M, Gomez G, Benitez J, Martínez-Delgado B - BMC Med Genomics (2010)

Differential signaling pathway activation in resistant and sensitive breast cancer cells upon treatment with 17AAG. Transfections were carried out in the sensitive (MCF-7 and Hs578T) and resistant (MDA MB 231 and T47D), cells with the reporter constructs for the typical cancer biology pathways: NOTCH, WNT, TGFβ, P53, cell cycle, MYC/MAX, NF-κB, MAPK/ERK, MAPK/JNK and HIF, followed by 17AAG or DMSO treatment. Dual-luciferase assay was performed, and promoter activity values are expressed as arbitrary units using a Renilla reporter for internal normalization. The experiment performed itself in triplicates was repeated at least twice of each cell line studied. The error bars represent standard deviation. Pathways significantly (p-value < 0.05) repressed or activated are marked with a star.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2959047&req=5

Figure 5: Differential signaling pathway activation in resistant and sensitive breast cancer cells upon treatment with 17AAG. Transfections were carried out in the sensitive (MCF-7 and Hs578T) and resistant (MDA MB 231 and T47D), cells with the reporter constructs for the typical cancer biology pathways: NOTCH, WNT, TGFβ, P53, cell cycle, MYC/MAX, NF-κB, MAPK/ERK, MAPK/JNK and HIF, followed by 17AAG or DMSO treatment. Dual-luciferase assay was performed, and promoter activity values are expressed as arbitrary units using a Renilla reporter for internal normalization. The experiment performed itself in triplicates was repeated at least twice of each cell line studied. The error bars represent standard deviation. Pathways significantly (p-value < 0.05) repressed or activated are marked with a star.
Mentions: Interestingly, the results revealed that NF-κB and MAPK/JNK pathway were found significantly activated in both resistant compared to the sensitive cell lines (Figure 5). Although below statistical significance, GSEA revealed NF-κB as one of the most relevant pathways associated to 17AAG resistance. The increased activity of the NF-κB, may indicate that this pathway plays an important role in cell survival upon treatment. Additionally, MAPK pathways could have also some role in the resistance to 17AAG, as MAPK/JNK was significantly activated in both resistant T47 D and MDA-MB-231 cell lines, and the MAPK/ERK was induced in T47 D. Cell cycle pathway was significantly activated only in MDA-MB-231 resistant cell line, what may reflect the higher proliferation status of these cells. Sensitive MCF-7 cells showed a critical reduction in the activity of all of the pathways, which correlate with the stop in proliferation and death induced after the treatment (Figure 5). The other sensitive cell line, Hs578T also showed inhibition of most of the pathways except NOTCH, TGF and Hypoxia pathway.

Bottom Line: In addition, different patterns of HSP90 client transcriptional changes after 17AAG were identified associated to the sensitive cell lines, which could be useful to evaluate drug effectiveness.Finally, we have found differentially expressed pathways associated to resistance to 17AAG.Our study shows that global mRNA expression analysis is a useful strategy to examine molecular effects of drugs, which allowed us the discovery of new biomarkers of 17AAG activity and provided more insights into the complex mechanism of 17AAG resistance.

View Article: PubMed Central - HTML - PubMed

Affiliation: Human Genetics Group, Spanish National Cancer Centre, Madrid, Spain.

ABSTRACT

Background: HSP90 may be a favorable target for investigational therapy in breast cancer. In fact, the HSP90 inhibitor, 17AAG, currently has entered in phase II clinical trials as an anticancer agent in breast and other tumors. Since HSP90 inhibition leads to global depletion of oncogenic proteins involved in multiple pathways we applied global analysis using gene array technology to study new genes and pathways involved in the drug response in breast cancer.

Methods: Gene expression profiling using Whole Human Genome Agilent array technology was applied to a total of six sensitive and two resistant breast cancer cell lines pre-treatment and treated with the 17AAG for 24 and 48 hours.

Results: We have identified a common molecular signature of response to 17AAG composed of 35 genes which include novel pharmacodynamic markers of this drug. In addition, different patterns of HSP90 client transcriptional changes after 17AAG were identified associated to the sensitive cell lines, which could be useful to evaluate drug effectiveness. Finally, we have found differentially expressed pathways associated to resistance to 17AAG. We observed significant activation of NF-κB and MAPK pathways in resistant cells upon treatment, indicating that these pathways could be potentially targeted to overcome resistance.

Conclusions: Our study shows that global mRNA expression analysis is a useful strategy to examine molecular effects of drugs, which allowed us the discovery of new biomarkers of 17AAG activity and provided more insights into the complex mechanism of 17AAG resistance.

Show MeSH
Related in: MedlinePlus