Summary: | Naringenin, an abundant flavanon in the peel of citrus fruits is reported to
possess anti-proliferative effect in many cancer cells. Herein, we investigated the
cytotoxic effect and apoptosis induction of naringenin in combination with
doxorubicin on HeLa cells.
The cytotoxicity assay of naringenin, doxorubicin, and their combination
were carried out by using MTT method. Cell viability and combination index
were used as the parameters to evaluate combination effectiveness. Cell cycle
distribution was determined by flow cytometry and then analyzed by using
ModFit LT 3.0 program. Apoptosis assay was done using double staining method
using Ethidium Bromide-Acridine Orange. Investigation on the expression of Bax
and Bcl-2 were determined by immunocytochemistry method.
Naringenin and doxorubicin showed cytotoxic effect on HeLa cells with
their IC50 values of 195 uM and 1 µM, respectively. Treatment of naringenin
combined with doxorubicin for 24 and 48 hours showed greater cytotoxicity
compared with single treatment of doxorubicin. Based on CI values, combination
naringenin 25 µM and doxorubicin 0,5 µM was the best synergistic effect. Single
treatment of 0,5 µM doxorubicin for 24 hours in HeLa cells induced S-phase
arrest. Although 100 µM naringenin did not affect HeLa cell cycle, its
combination with 0,5 µM doxorubicin induced S-phase arrest with increased
percentage of sub-G1 phase. In accordance with the flow cytometry results, the
apoptosis assay of combination treatment indicated increase of apoptotic cells
compared than single treatment. Naringenin, doxorubicin, and their combination
also increased the expression of Bax and decreased the expression of Bcl-2. These
results conclude that naringenin is a potential co-chemotherapy agent for cervical
cancer due to its synergism with doxorubicin.
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