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Feng Wu, Fuxingzi Li, Xiao Lin, Feng Xu, Rong-Rong Cui, Jia-Yu Zhong, Ting Zhu, Su-Kang Shan, Xiao-Bo Liao, Ling-Qing Yuan, and Zhao-Hui Mo

Tumour-derived exosomes under hypoxic conditions contain informative miRNAs involved in the interaction of cancer and para-carcinoma cells, thus contributing to tissue remodelling of the tumour microenvironment (TME). Exosomes isolated from hypoxic papillary thyroid cancer cells, BCPAP cells and KTC-1 cells enhanced the angiogenesis of human umbilical vein endothelial cells (HUVECs) compared with exosomes isolated from normal thyroid follicular cell line (Nthy-ori-3-1), normoxic BCPAP or KTC-1 cells both in vitro and in vivo. miR-21-5p was significantly upregulated in exosomes from papillary thyroid cancer BCPAP cells under hypoxic conditions, while the exosomes isolated from hypoxic BCPAP cells with knockdown of miR-21-5p attenuated the promoting effect of angiogenesis. In addition, our experiment revealed that miR-21-5p directly targeted and suppressed TGFBI and COL4A1, thereby increasing endothelial tube formation. Furthermore, elevated levels of exosomal miR-21-5p are found in the sera of papillary thyroid cancer patients, which promote the angiogenesis of HUVECs. Taken together, our study reveals the cell interaction between hypoxic papillary thyroid cancer cells and endothelial cells, elucidating a new mechanism by which hypoxic papillary thyroid cancer cells increase angiogenesis via exosomal miR-21-5p/TGFBI and miR-21-5p/COL4A1 regulatory pathway.

Restricted access

Qun Liu, Hui-ting Dong, Tingting Zhao, Fan Yao, Yingying Xu, Bo Chen, Yunfei Wu, Feng Jin, and Peng Xing

Cancer-associated adipocytes (CAAs) have been suggested to promote tumor progression. Yet, the role of CAAs in triple-negative breast cancer (TNBC) is poorly investigated. We compared the expression of secretory protein-encoding genes in CAAs and control adipocytes. The effect of key secretory protein(s) on TNBC cell behaviors was explored. CAAs expressed and secreted FUCA2 at greater levels than control adipocytes. When FUCA2 activity was blocked with a neutralizing antibody, TNBC cell proliferation and migration induced by CAA-conditioned medium was impaired. In contrast, supplement of exogenous FUCA2 protein reinforced the proliferation, colony formation, and migration of TNBC cells. In vivo studies confirmed that FUCA2 exposure enhanced tumorigenesis and metastasis of TNBC cells. Mechanistic investigation revealed that FUCA2 induced TNBC aggressiveness through TM9SF3-dependent signaling. Depletion of TM9SF3 blocked CAA- and FUCA2-induced TNBC cell proliferation and migration. Compared to adjacent breast tissues, TNBC tissues had increased expression of TM9SF3. Moreover, high TM9SF3 expression was associated with advanced TNM stage, lymph node metastasis, and shorter overall survival of TNBC patients. Altogether, CAAs secrete FUCA2 to promote TNBC growth and metastasis through interaction with TM9SF3. Inhibition of TM9SF3 may represent a potential therapeutic strategy in the treatment of TNBC.

Free access

Yangang Wang, Meiju Ji, Wei Wang, Zhimin Miao, Peng Hou, Xinyan Chen, Feng Xu, Guangwu Zhu, Xianlu Sun, Yujun Li, Steven Condouris, Dingxie Liu, Shengli Yan, Jie Pan, and Mingzhao Xing

The relationship among BRAF mutation, platelet counts, and platelet-derived growth factor (PDGF) with respect to clinicopathological outcomes of papillary thyroid cancer (PTC) may play a role in PTC pathogenesis but remains undefined. We examined the T1799A BRAF mutation by direct genomic DNA sequencing in 108 primary PTC samples from a Chinese cohort and analyzed its relationship with clinicopathological, hematological, and other laboratory results as well as the levels of expression of PDGF in tumors. We found that the BRAF mutation was significantly associated with extrathyroidal invasion and advanced tumor stages III and IV. Specifically, extrathyroidal invasion was seen in 30/54 (56%) PTC with BRAF mutation versus 18/54 (33%) PTC without the mutation (P=0.02). Tumor stages III and IV were seen in 16/54 (30%) PTC with BRAF mutation versus 7/54 (13%) PTC without the mutation (P=0.04). The BRAF mutation was also significantly associated with a higher platelet count, with 249.28±53.76×109/l in the group of patients with BRAF mutation versus 207.79±58.98×109/l in the group without the mutation (P=0.001). An association of higher platelet accounts with extrathyroidal invasion was also seen, with 242.66±51.85×109/l in patients with extrathyroidal invasion versus 218.49±59.10×109/l in patients without extrathyroidal invasion (P=0.03). The BRAF T1799A-positive PTC tissues harbored a significantly higher level of PDGF-B than BRAF T1799A-negative PTC tissues. The data suggest that the BRAF T1799A mutation is associated with aggressive pathological outcomes of PTC in which high platelet counts and increased PDGF production may play a role.

Open access

Gina Chia-Yi Chu, Haiyen E Zhau, Ruoxiang Wang, André Rogatko, Xu Feng, Majd Zayzafoon, Youhua Liu, Mary C Farach-Carson, Sungyong You, Jayoung Kim, Michael R Freeman, and Leland W K Chung

Prostate cancer (PCa) metastasis to bone is lethal and there is no adequate animal model for studying the mechanisms underlying the metastatic process. Here, we report that receptor activator of NF-κB ligand (RANKL) expressed by PCa cells consistently induced colonization or metastasis to bone in animal models. RANK-mediated signaling established a premetastatic niche through a feed-forward loop, involving the induction of RANKL and c-Met, but repression of androgen receptor (AR) expression and AR signaling pathways. Site-directed mutagenesis and transcription factor (TF) deletion/interference assays identified common TF complexes, c-Myc/Max, and AP4 as critical regulatory nodes. RANKL–RANK signaling activated a number of master regulator TFs that control the epithelial-to-mesenchymal transition (Twist1, Slug, Zeb1, and Zeb2), stem cell properties (Sox2, Myc, Oct3/4, and Nanog), neuroendocrine differentiation (Sox9, HIF1α, and FoxA2), and osteomimicry (c-Myc/Max, Sox2, Sox9, HIF1α, and Runx2). Abrogating RANK or its downstream c-Myc/Max or c-Met signaling network minimized or abolished skeletal metastasis in mice. RANKL-expressing LNCaP cells recruited and induced neighboring non metastatic LNCaP cells to express RANKL, c-Met/activated c-Met, while downregulating AR expression. These initially non-metastatic cells, once retrieved from the tumors, acquired the potential to colonize and grow in bone. These findings identify a novel mechanism of tumor growth in bone that involves tumor cell reprogramming via RANK–RANKL signaling, as well as a form of signal amplification that mediates recruitment and stable transformation of non-metastatic bystander dormant cells.

Restricted access

Feng Xu, Yali Ling, Jingjing Yuan, Qin Zeng, Lusha Li, Dexing Dai, Xuedi Xia, Ruoman Sun, Ran Zhang, and Zhongjian Xie

Differentiated thyroid carcinoma (DTC) is the most common endocrine malignancy and highly expresses the receptor for 1,25-dihydroxyvitamin D (1,25(OH)2D). However, it is unclear whether 1,25(OH)2D regulates DTC proliferation and differentiation. Here, we found that 1,25(OH)2D3 inhibited proliferation but not differentiation of the DTC cells. Notably, CYP27B1was elevated in DTC cells and 25-hydroxyvitamin D3 (25(OH)D3) reduced DTC cell proliferation. Knockdown of VDR did not affect the anti-proliferative effects of 1,25(OH)2D3. However, knockdown of CCAAT enhancer-binding protein β (C/EBPβ)abolished 1,25(OH)2D3-suppressed DTC cell proliferation. In addition, 1,25(OH)2D3 induced phosphorylation and translocation of C/EBPβto the nucleus from the cytoplasm. However, inhibition of p38 mitogen-activated protein kinases (MAPK) abrogated 1,25(OH)2D3-induced phosphorylation and nuclear translocation of C/EBPβas well as 1,25(OH)2D3-suppressed DTC cell proliferation. Knockdown of C/EBPβreduced the expression of Notch3. Knockdown of Notch3 blocked 1,25(OH)2D3-suppressed DTC cell proliferation. In the DTC cell-derived xenograft SCID mouse, knockdown of C/EBPβmarkedly increased tumor growth and proliferation and decreased apoptosis. In DTC patients, C/EBPβwas predominantly located in the cytoplasm of DTC cells in the tumor tissue when compared with adjacent non-cancerous tissue in which C/EBPβis located in the nucleus. In conclusion, C/EBPβstimulated Notch3signaling via the p38 MAPK-dependent pathway mediates the inhibitory effect of 1,25(OH)2D on DTC cell proliferation.

Free access

Feng Wu, Fuxingzi Li, Xiao Lin, Feng Xu, Rong-Rong Cui, Jia-Yu Zhong, Ting Zhu, Su-Kang Shan, Xiao-Bo Liao, Ling-Qing Yuan, and Zhao-Hui Mo