PHGDH knockdown increases sensitivity to SR1, an aryl hydrocarbon receptor antagonist, in colorectal cancer by activating the autophagy pathway

Colorectal cancer (CRC) has emerged as the third most prevalent and second deadliest cancer worldwide. Metabolic reprogramming is a key hallmark of cancer cells. Phosphoglycerate dehydrogenase (PHGDH) is over-expressed in multiple cancers, including CRC. Although the role of PHGDH in metabolism has been extensively investigated, its effects on CRC development remains to be elucidated. In the present study, it was demonstrated that PHGDH expression was significantly up-regulated in colorectal cancer. PHGDH expression was positively correlated with that of the aryl hydrocarbon receptor (AhR) and its target genes, CYP1A1 and CYP1B1, in CRC cells. Knockdown of PHGDH reduced AhR levels and activity, as well as the ratio of reduced to oxidized glutathione. The selective AhR antagonist stemregenin 1 induced cell death through reactive oxygen species-dependent autophagy in CRC cells. PHGDH knockdown induced CRC cell sensitivity to stemregenin 1 via the autophagy pathway. Our findings suggest that PHGDH modulates AhR signaling and the redox-dependent autophagy pathway in CRC, and that the combination of inhibition of both PHGDH and AhR may be a novel therapeutic strategy for CRC.

KDM4B down-regulation facilitated breast cancer cell stemness via PHGDH upregulation in H3K36me3-dependent manner

Despite recent advances have been made in clinical treatments of breast cancer, the general prognosis of patients remains poor. Therefore, it is imperative to develop a more effective therapeutic strategy. Lysine demethylase 4B (KDM4B) has been reported to participate in breast cancer development recently, but its exact biological role in breast cancer remains unclear. Here, we observed that KDM4B was down-regulated in human primary BRCA tissues and the low levels of KDM4B expression were correlated with poor survival. Gain- and loss-of-function experiments showed that KDM4B inhibited the proliferation and metastasis of breast cancer cells. Besides, knockdown of KDM4B promoted the epithelial-mesenchymal transition (EMT) and cell stemness in breast cancer cells. Mechanistically, KDM4B down-regulates PHGDH by decreasing the enrichment of H3K36me3 on the promoter region of PHGDH. Knockdown of PHGDH could significantly reversed proliferation, migration, EMT, and cell stemness induced by KDM4B silencing in breast cancer cells. Collectively, we propose a model for a KDM4B/PHGDH axis that provides novel insight into breast cancer development, which may serve as a potential factor for predicting prognosis and a therapeutic target for breast cancer.

Structures and magnetism of two novel heptanuclear lanthanide-centered trigonal prismatic clusters: [LnCu6(mu 3-OH)3(HL)2(L)4](ClO4)2.25H2O (Ln = La, Tb; H2L = iminodiacetic acid)

The new heteronuclear iminodiacetic acid (H2L) complexes [LnCu6(mu 3-OH)3(HL)2(L)4](ClO4)(2).25H2O with Ln = La (1) and Tb (2) have been prepared in aqueous solution and characterized by single-crystal X-ray diffraction to be isomorphous (crystallographic data for 1 and 2: hexagonal, P63/m; a = b = 12.6425(14) A, c = 24.541(5) A, Z = 2 (1); a = b = 12.5802(9) A, c = 24.285(4) A, Z = 2 (2)). Ln3+ was found to be located in the center of the trigonal prismatic cage formed by six Cu2+ ions, with a tricapped trigonal prismatic coordination environment of nine O atoms. The magnetic properties of complexes 1 and 2 have been studied. The results indicate the presence of ferromagnetic couplings between Tb3+ and Cu2+ in compound 2.