HMGB1-RAGE signaling facilitates Ras-dependent Yap1 expression to drive colorectal cancer stemness and development
MOLECULAR CARCINOGENESIS
Authors: Qian, Fei; Xiao, Jianjia; Gai, Ling; Zhu, Jianwei
Abstract
HMGB1-RAGE signaling plays an integral role in inflammation-driven carcinogenesis. In the present study, we showed that RAGE has direct association with K-Ras following HMGB1 exposure in colorectal cancer (CRC) cells. Immunofluorescence analysis revealed a significant co-localization between RAGE and K-Ras in HMGB1-exposed CRC cells. Moreover, we uncovered that HMGB1-mediated RAGE activation led to Yap1 accumulation in a Ras-dependent mechanism in CRC cells. HMGB1 activated the expression of Yap1 downstream stemness marker proteins CD44 and Sox2 in RAGE- and Ras-dependent manners. Furthermore, HMGB1 exposure led to the proliferation of CRC cells and the expansion of CRC stem cells. RAGE, Yap1 and CD44 were overexpressed in CRC specimens. Linear regression analysis revealed that the expression of RAGE was positively correlated with Yap1 in clinical CRC specimens. Both of RAGE and Yap1 expression were correlated with advanced histological grades, lymph node metastasis and TNM stages. Finally, we revealed that both of RAGE and Yap1 expression could predicted unfavorable prognosis in CRC patients. These findings implicated that HMGB1-RAGE signaling may promote Yap1 activation and CRC progression, shedding new light on the mechanisms underlying inflammation-driven CRC development.
Characterisation of the Hippo signalling pathway during bovine preimplantation embryo development
REPRODUCTION FERTILITY AND DEVELOPMENT
Authors: Sharma, Jyoti; Madan, Pavneesh
Abstract
Blastocyst formation is an important milestone during preimplantation embryo development. During murine preimplantation embryogenesis, the Hippo signalling pathway is known to play a significant role in lineage segregation and henceforth the formation of blastocysts. However, the role of this cell signalling pathway during bovine embryogenesis remains unknown. Thus, the aim of the present study was to characterise the Hippo signalling pathway during bovine preimplantation embryo development. mRNA transcripts of Hippo signalling pathway constituents (i.e. crumbs cell polarity complex component 3 (CRB3), mammalian sterile 20-like 1 (MST1), mammalian sterile 20-like 2 (MST2), Yes associated protein 1 (YAP1), transcriptional coactivator with PDZ-binding motif (TAZ)) were observed during all stages of bovine preimplantation embryo development. To evaluate the localisation of Hippo pathway components, bovine embryos at timed stages of development were stained using specific antibodies and observed under a laser confocal microscope. Although MST1/2 proteins were in the cytoplasm during various stages of bovine embryonic development, TAZ and phosphorylated (p-) YAP were detected in the nucleus during the blastocyst stages. Localisation of TAZ and p-YAP proteins was distinct in the bovine compared with mouse model, suggesting that the Hippo signalling pathway is regulated differently in early bovine embryos.