Effect of idarubicin/trastuzumab combinatorial therapy on her2-positive breast cancer cell lines

Aminollah Pourshohod,1,* Mostafa jamalan,2 Majid zeinali,3 Moslem afrakhte,4

1. Department of Biochemistry, Cellular and Molecular Research Center, Ahvaz Jundishapur University of medical science, Medical School, Ahvaz, Iran
2. Abadan School of Medical Sciences, Abadan, Iran
3. Biotechnology Research Center, Research Institute of Petroleum Industry (RIPI), Tehran, Iran
4. Department of Biochemistry, Cellular and Molecular Research Center, Ahvaz Jundishapur University of medical science, Medical School, Ahvaz, Iran

Abstract

Introduction

Human epidermal growth factor receptor (her) family is a four-member group of transmembrane receptors consisting of her1, her2, her3, and her4. among them, her2 does not have any known ligand and its over-expression is associated with various kinds of malignancies. over-expression of her2 receptor on the surface of many human tumor cells such as breast, head and neck, gastric, ovarian, bladder, endometrial, pancreatic and non-small-cell lung cancer has been demonstrated. chemotherapy and immunotherapy (blockage of her2 dimerization using monoclonal antibodies) are two main treatment approaches in the cancer therapy. idarubicin and trastuzumab are two anti-tumor drugs that are used in cancer therapy. anti-proliferative activity of idarubicin (an inhibitor of topoisomerase ii), alone or in combination with other chemotherapeutic drugs, against cancer cells has been extensively studied and mechanism of toxicity has been completely known. solubility of idarubicin in lipid compounds is considerably more compared to its counterparts, and therefore can be absorbed more effectively by cells. trastuzumab is the first humanized monoclonal antibody (mab) against the her2 receptor that approved by fda for administration in patients with her2-overexpressing breast cancer. trastuzumab as a single therapeutic agent could exert anti-tumor activity in human, but its efficiency could also be improved by combination with other chemotherapeutic drugs. in the current study, the combined effect of idarubicin and trastuzumab on the viability of her2 positive cancer cells was investigated.

Methods

Sk-br-3 and mcf-7 cell lines were seeded at approximately 5×103 cells well−1 in complete dmem high glucose medium into flat-bottom 96-well plates (nunc, rosklide, denmark) and then incubated overnight at 37°c, 5% co2. cells were exposed for 72 h to various concentrations of idarubicin (0.5-10 ng ml−1), trastuzumab (1-1000 ng ml−1) and idarubicin/trastuzumab (1-1000 ng ml−1 of trastuzumab and 5 ng ml-1 of idarubicin). after incubation time, cell viability was determined by mtt assay for mitochondrial function. her2 expression levels of sk-br-3 and mcf-7 cell lines were assessed by western blotting.

Results

According to the obtained results, idarubicin at concentrations higher than 5 ng/ml could significantly decreased viability of sk-br-3 and mcf-7 cell lines in a dose dependent manner. idarubicin at 5 ng/ml diminished viability of mcf-7 and sk-br-3 cells to 82.1 and 79.55% in comparison to the control group, and so this concentration was selected for combinatorial therapy of indicated malignant cell lines. sk-br-3 as a her2-overexpressing cell line and mcf-7 as a cell line with normal expression of her2 were treated by trastuzumab. while trastuzumab at 100 ng/ml could significantly diminished viability of sk-br-3 cells to 81.8% compared to untreated control group but no anti-proliferative effect was seen against mcf-7 cell line. at this concentration of trastuzumab, addition of idarubicin decreased viability of sk-br-3 and mcf-7 cells to 67.67% and 77.12% compared to untreated control. this effect was also seen at higher concentrations of trastuzumab.

Conclusion

: our obtained results showed that treatment of malignant cells by trastuzumab and idarubicin simultaneously and at optimized concentrations could be a beneficial route of combinatorial therapy for more specific treatment of her2-overexpressing cell lines. more in vivo and in vitro assessment seems to be required for introducing this kind of cancer therapy as a new clinical treatment protocol.

Keywords

Combinatorial therapy, idarubicin/trastuzumab, her2