HIF-1 activation induces doxorubicin resistance in MCF7 3-D spheroids via P-glycoprotein expression: a potential model of the chemo-resistance of invasive micropapillary carcinoma of the breast

BMC Cancer

Research Article

Anna Sapino¹  Elena Allia¹  Laura Annaratone¹  Dimas C Belisario²  Manuela Polimeni²  Dario Ghigo²  Amalia Bosia²  Chiara Riganti²  Sophie Doublier² 

[1] Department of Biomedical Sciences and Human Oncology, University of Turin, Turin, Italy;Department of Genetics, Biology and Biochemistry, University of Turin, Via Santena, 5/bis, 10126, Turin, Italy;Center of Experimental Research and Medical Sciences, University of Turin, Turin, Italy;

关键词: HIF-1α;    3-D spheroids, Elastase;    Invasive micropapillary breast carcinoma;    Doxorubicin resistance;    P-glycoprotein;    MUC-1;   

DOI  :  10.1186/1471-2407-12-4

 received in 2011-04-14, accepted in 2012-01-04,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundInvasive micropapillary carcinoma (IMPC) of the breast is a distinct and aggressive variant of luminal type B breast cancer that does not respond to neoadjuvant chemotherapy. It is characterized by small pseudopapillary clusters of cancer cells with inverted cell polarity. To investigate whether hypoxia-inducible factor-1 (HIF-1) activation may be related to the drug resistance described in this tumor, we used MCF7 cancer cells cultured as 3-D spheroids, which morphologically simulate IMPC cell clusters.MethodsHIF-1 activation was measured by EMSA and ELISA in MCF7 3-D spheroids and MCF7 monolayers. Binding of HIF-1α to MDR-1 gene promoter and modulation of P-glycoprotein (Pgp) expression was evaluated by ChIP assay and FACS analysis, respectively. Intracellular doxorubicin retention was measured by spectrofluorimetric assay and drug cytotoxicity by annexin V-FITC measurement and caspase activity assay.ResultsIn MCF7 3-D spheroids HIF-1 was activated and recruited to participate to the transcriptional activity of MDR-1 gene, coding for Pgp. In addition, Pgp expression on the surface of cells obtained from 3-D spheroids was increased. MCF7 3-D spheroids accumulate less doxorubicin and are less sensitive to its cytotoxic effects than MCF7 cells cultured as monolayer. Finally, HIF-1α inhibition either by incubating cells with 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (a widely used HIF-1α inhibitor) or by transfecting cells with specific siRNA for HIF-1α significantly decreased the expression of Pgp on the surface of cells and increased the intracellular doxorubicin accumulation in MCF7 3-D spheroids.ConclusionsMCF7 breast cancer cells cultured as 3-D spheroids are resistant to doxorubicin and this resistance is associated with an increased Pgp expression in the plasma membrane via activation of HIF-1. The same mechanism may be suggested for IMPC drug resistance.

【 授权许可】

CC BY   
© Doublier et al; licensee BioMed Central Ltd. 2011