Elevated de novo lipogenesis is one of the most
important hallmarks of altered metabolism in pancreatic
cancer and liver cancer and has been proposed to be a new
drug target for the development of anti-cancer agents [4].
A previous study has indicated that increased lipogenesis
is associated with development and progression of human
hepatocellular carcinoma [20]. The newly synthesized
lipid can be used for building cell membrane during cell
proliferation and providing fuel for rapid growth cancer
cell when demanded. Recently, increasing evidence
suggests that the lipid may play important roles in
signaling transduction associated with tumor growth [21;
22]. Overexpression of genes encoding lipogenic enzymes
was responsible for the elevated lipid biosynthesis in
cancer [23]. Among them, ACC and FASN are two
important enzymes during cell de novo lipogenesis. The
significant role of FASN and ACC in cancer development
has been well established in the past [24; 25]. Elevated
expression of FASN and ACC in cancer cells is related
to markedly worse prognosis in many human cancers,
including pancreatic cancer [4]. Inhibit the expression
of FASN and ACC by metformin prevents liver
tumorigenesis [26]. In this study, our results demonstrated
that GA possesses a potent inhibitory effect on cancer cell
growth both in vitro and in vivo. Moreover, de novo lipid
synthesis in cancer cells was dramatically attenuated by
GA. Inhibition of critical genes involved in lipid synthesis
could be the basis of these effects induced by GA.
SREBPs are a family of transcription factors that
regulate lipid homeostasis by regulating the expression
of the core and rate-limiting enzymes involved in lipid
synthesis, including ACC and FASN [27]. Three SREBP
isoforms, SREBP-1a, SREBP-1c and SREBP-2, have been
identified in mammalian cells. Among them, SREBP-1a
and SREBP-1c were encoded by a same gene SREBF-1
while SREBP-2 was encoded by SREBF-2. The biological
function of SREBP-1 is to control the lipogenic gene