Leptin, a
hormone primarily derived from adipose tissue, is known to induce
tumor growth, but its underlying mechanisms of action are not clearly understood.
Inflammasomes, acting as signaling platforms for controlling inflammatory responses, modulate
tumor growth in a complicated manner. In this study, we investigated the role of
inflammasomes in
leptin-induced growth of
breast cancer cells. Herein, we showed that
leptin activated NLRP3
inflammasomes in MCF-7
breast cancer cells, as determined by activation of caspase-1, maturation of interleukin-1β, and increased expression of the
inflammasome components, including NLRP3 and ASC. Interestingly, inhibition of the
inflammasome by treatment with a pharmacological inhibitor of caspase-1 or gene silencing of NLRP3 prevented
leptin-induced increase in cell viability. Moreover, suppression of apoptosis and cell cycle promotion by
leptin were also significantly abolished by gene silencing of NLRP3, clearly indicating a crucial role of NLRP3
inflammasomes in
leptin-induced
breast cancer growth. In addition, inhibition of
estrogen receptor signaling or ROS production markedly blocked
leptin-induced activation of NLRP3
inflammasomes, suggesting that
estrogen receptor signaling and ROS production mediate
inflammasomes activation by
leptin. The stimulatory effect of
leptin on
inflammasomes activation was also observed in MCF-7
tumor xenograft model. Furthermore, the critical roles of
inflammasomes activation in
leptin-induced
tumor growth, suppression of apoptotic gene expression, and induction of the genes stimulating cell cycle were confirmed in a
tumor xenograft model. Taken together, these results demonstrate that
inflammasomes activation plays a pivotal role in
leptin-induced growth of
breast cancer cells via modulation of both apoptosis and cell cycle.