Background and Objective: Phenformin, and
flavonoid compounds, quercetin and myricetin are
effective against many types of cancers. This study
evaluated the treatments of phenformin in
combination with quercetin or myricetin in the
inhibition of cholangiocarcinoma (CCA) cells.
Methods: Cholangiocarcinoma cells, KKU-156, were
used in this study. Cell cytotoxicity was evaluated by
sulforhodamine-B assay (SRB). Mitochondrial
transmembrane potential (ΔΨm) was analyzed by
JC-1 assay.
Results: Phenformin significantly inhibited proliferation
of cancer cells. Phenformin in combination with
quercetin, but not myricetin, could increase the
cytotoxicity of cancer cells. Phenformin, quercetin or
in the combination induced the loss of
mitochondrial transmembrane potential.
Conclusions: Quercetin increased phenformin in
inhibition of cancer cell growth. The mechanism may
be by the increase of induction of mitochondrial
damage leading to cell death. This finding suggests
that phenformin in combination with quercetin has
potential to increase efficacy of chemotherapy of
cholangiocarcinoma.