Involvement of interleukin-1β in high glucose-activated proliferation of cholangiocarcinoma.

BACKGROUND

Diabetes mellitus (DM) is associated with the increased risk of development and the advancement of cholangiocarcinoma (CCA). High glucose levels were previously shown for upregulating interleukin-1β (IL-1β) in CCA cells with unclear functions. The present study, thus, aimed to investigate molecular mechanisms linking DM to CCA progression, with IL-1β hypothesized as a communicating cytokine.

METHODS

CCA cells were cultured in media with normal (5.6 mM) or high (25 mM) glucose, resembling euglycemia and hyperglycemia, respectively. Expressions of IL-1β and IL-1 receptor (IL-1R) in CCA tissues from patients with and without DM were examined using immunohistochemistry. Functional analyses of IL-1β were performed using siRNA and recombinant human IL-1R antagonist (rhIL-1RA), in which Western blots investigated the knockdown efficacy. BALB/c (BRJ) mice were implanted with CCA xenografts to investigate hyperglycemia's effects on CCA growth and the anti-tumor effects of IL-1RA.

RESULTS

CCA tumors from patients with hyperglycemia showed significantly higher IL-1β expression than those from non-DM patients, while IL-1β was positively correlated with fasting blood glucose (FBG) levels. CCA cells cultured in high glucose showed increased IL-1β expression, resulting in increased proliferation rates. Suppressing IL-1β signaling by si-IL-1β or rhIL-1RA significantly reduced CCA cell proliferation . Anakinra, a synthetic IL-1RA, also exerted significant anti-tumor effects and significantly reversed the effects of hyperglycemia-induced growth in CCA xenografts.

CONCLUSIONS

IL-1β plays a crucial role in CCA progression in a high-glucose environment. Targeting IL-1β might, then, help improve therapeutic outcomes of CCA in patients with DM and hyperglycemia.