Title:Dihydrotestosterone Induces Chemo-Resistance of Triple-Negative Breast MDA-MB-231 Cancer Cells Towards Doxorubicin Independent of ABCG2 and miR-328-3p
Volume: 14
Author(s): Bayan Al-Momany, Hana Hammad and Mamoun Ahram*
Affiliation:
- Department of Physiology and Biochemistry, School of Medicine, The University of Jordan, Amman,Jordan
Keywords:
Triple-negative breast cancer, androgen receptor, dihydrotestosterone, breast cancer resistant protein, miR-328-3p,
ABCG2 Protein.
Abstract:
Background: Androgens potentially have an important role in the biology of breast cancer,
particularly triple-negative breast cancer (TNBC). Androgen receptor (AR) may offer a novel
therapeutic strategy, including the use of microRNA (miRNA) molecules. We have previously
shown that AR agonist, dihydrotestosterone (DHT), increases the expression of miR-328-3p in the
TNBC MDA-MB-231 cells. One target of the latter miRNA is ATP-binding cassette subfamily G
member 2 (ABCG2), which modulates the chemo-response of cancer cells by pumping out xenobiotics.
Objective: Using MDA-MB-231 cells as a model system for TNBC, we hypothesized that DHT
would induce cell sensitivity towards doxorubicin via increasing levels of miR-328-3p and, consequently,
reducing ABCG2 levels.
Methods: Chemo-response of cells towards doxorubicin, tamoxifen, and mitoxantrone was evaluated
using cell viability MTT assay. Cells were transfected with both miR-328-3p mimic or antisense
molecules. Real-time PCR was utilized to assess RNA levels and immunoblotting was performed
to investigate levels of ABCG2 protein. PCR arrays were used to assess changes in the expression
of drug response regulatory genes.
Results: Contrary to our hypothesis, treating MDA-MB-231 cells with DHT no effect towards tamoxifen
or mitoxantrone, increased cell resistance towards doxorubicin was noted, concomitant
with decreased expression of ABCG2. This under-expression of ABCG2 was also found in MCF-7
and MDA-MB-453 cells treated with DHT. Although miR-328-3p decreased ABCG2 mRNA and
protein levels, the miRNA did not alter the chemo-response of cells towards doxorubicin and did
not affect DHT-induced chemo-resistance. AR activation slightly decreased the expression of 5
genes, including insulin-like growth factor 1 receptor that may explain the mechanism of DHT-induced
chemo-resistance of cells.
Conclusion: DHT regulates chemo-response via a mechanism independent of ABCG2 and
miR-328-3p.