which in turn was associated with generation of ROS. Pretreatment of
Capan-2 cells with antioxidant NAC blocked ROS
generation and completely protected the cells from Triphalainduced
apoptosis. The results also demonstrate that
Triphala treatment caused DNA damage resulting in the
activation of ATM and ERK leading to stabilization.
Blocking ERK activation by MEK-1/2 inhibitor U0126 or
p53 activation by pifithrin-a completely protected Capan-2
(wild type p53) cells from Triphala-induced apoptosis.
Similarly, U0126 treatment blocked Triphala-induced
apoptosis in BxPC-3 (mutated p53) cells, suggesting ERK as
a molecular target of Triphala in pancreatic cancer cells.
Further, orally feeding 50 mg/kg or 100 mg/kg Triphala to
nude mice significantly retarded the growth of Capan-2
pancreatic tumor xenograft. Tumors from Triphala treated
mice demonstrated increased apoptosis in the tumor cells,
which was due to the activation of ERK and p53. To the best
of our knowledge, this is the first study to report the
molecular mechanism of the chemotherapeutic effects of
Triphala against pancreatic cancer.
Reactive oxygen species (ROS) are the known mediators of
intracellular signaling cascades. Excessive production of
ROS nonetheless leads to oxidative stress, loss of cell
function and apoptosis or necrosis 14-17. Our results reveal
that Triphala-induced apoptosis in pancreatic cancer cells is
initiated by ROS generation, the effect of which can be
blocked by antioxidant NAC. Several previous studies
including those from our laboratory have implicated ROS as
a possible mechanism for DNA damage and induction of
apoptosis [15, 17, 18]. DNA damage plays a critical role in
maintaining genomic integrity. Tumor cells exhibit genetic
instability causing functional inactivation of p53 that plays
an important role in DNA damage checkpoint pathways. In
response to DNA damage, p53 is stabilized through
phosphorylation at Ser 15 by ATM 19-21. The effects of
Triphala are compatible with this assertion. The results do
indicate that Triphala treatment causes DNA damage as
depicted by increased phosphorylation of H2A.X at Ser 139,
an indicator for the presence of DNA double-strand breaks.
Pancreatic tumor growth inhibition and induction of
apoptosis In vivo was observed by the oral administration of
50 mg/kg or 100 mg/kg Triphala 5 times a week the results
were consistent with previous studies where Triphala was
shown to be effective in suppressing the growth of Barc- 95
(mouse thymic lymphoma) xenograft in mice22. Although,