Colon cancer is still the third most common cancer which has a high mortality but low five-year survival rate. Novel tyrosine kinase inhibitors (TKI) such as pazopanib become effective antineoplastic agents that show promising clinical activity in a variety of carcinoma, including colon cancer. However, the precise underlying mechanism against tumor is unclear. Here, we demonstrated that pazopanib promoted colon cancer cell apoptosis through inducing PUMA expression. Pazopanib induced p53-independent PUMA activation by inhibiting PI3K/Akt signaling pathway, thereby activating Foxo3a, which subsequently bound to the promoter of PUMA to activate its transcription. After induction, PUMA activated Bax and triggered the intrinsic mitochondrial apoptosis pathway. Furthermore, administration of pazopanib highly suppressed tumor growth in a xenograft model. PUMA deletion in cells and tumors led to resistance of pazopanib, indicating PUMA-mediated pro-apoptotic and anti-tumor effects in vitro and in vivo. Combing pazopanib with some conventional or novel drugs, produced heightened and synergistic antitumor effects that were associated with potentiated PUMA induction via different pathways. Taken together, these results establish a critical role of PUMA in mediating the anticancer effects of pazopanib in colon cancer cells and provide the rationale for clinical evaluation.

The relationship of obesity and osteoporosis has been widely studied over the past years. However, the implications of obesity for bone health remain controversial, and the underlying molecular mechanism is not yet fully understood.This study demonstrated that high-fat diet-induced obesity leads to significantly decreased bone volume/tissue volume (BV/TV), trabecular number (Tb.N), and cortical thickness (Ct.Th) of male rat femur after mechanical loading effects of body weight were controlled. HFD-induced obese rats exhibited attenuated expression of ferroptosis inhibitory protein SLC7A11 and GPX4 in bone tissues, which was correlated with elevated serum TNF-α concentration. Ferroptosis inhibitor administration could effectively rescue decreased osteogenesis-associated type H vessels and osteoprogenitors, and downregulate serum levels of TNF-α to ameliorate bone loss in obese rats. Since ferroptosis and TNF-α both affect bone and vessel formation, we further investigated the interaction between ferroptosis and TNF-α, and its impact in osteogenesis and angiogenesis in vitro. In human osteoblast-like MG63 and umbilical vein endothelial cells (HUVEC), TNF-α/ TNFR2 signaling promoted cystine uptake and GSH biosynthesis to provide protection against low-dose ferroptosis inducer erastin. While, TNF-α/TNFR1 facilitated ferroptosis in the presence of high-dose erastin through ROS accumulation.