Xing Wang

Cancer cells present sustained de novo fatty acid (FA) synthesis with increased production of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs). This change in FA metabolism is associated with overexpression of stearoyl-CoA desaturase 1 (SCD1), which catalyses the transformation of SFAs into MUFAs (e.g., oleic acid). In this study, we provide new evidence that SCD1 inhibition leads to the anti-proliferation effect of breast cancer cells through induction of apoptosis, cell cycle arrest and migration prevention. However, the antitumor effect of the SCD1 inhibitor can be reversed by exogenous oleic acid. We hypothesize that, in addition to de novo synthesis, cancer cells may uptake exogenous FAs actively. CD36, also known as FA translocase (FAT), that functions as a transmembrane protein and mediates the uptake of FAs, is observed to be highly expressed in breast cancer tissues. Furthermore, the anti-proliferation effect caused by the SCD1 inhibitor can not be reversed by exogenous oleic acid supplementation in CD36 knockdown breast cancer cells. Our study revealed that the lipid metabolism of breast cancer is regulated not only by de novo lipogenesis but also by the availability of lipids outside cancer cells. Consistent with FA synthesis, FA uptake and transport will be another important target pathway for anticancer therapy, and the FA channel protein CD36 may provide a promising therapeutic target. Lipogenesis combined with FA transport will be a new orientation for antitumor therapy.

PURPOSE: Childhood obesity increases susceptibility to type 2 diabetes (T2D) in adults. Circulating microRNAs (miRNAs) in serum have been proposed as potential diagnostic biomarkers, and they may contribute to the progression toward T2D. Here, we investigated the possibility of predicting the future risk of adult T2D in obese children by using circulating miRNAs. BASIC PROCEDURES: We performed miRNA high-throughput sequencing to screen relevant circulating miRNAs in obese children. The expression patterns of targeted miRNAs were further explored in obese children and adults with T2D. To investigate the underlying contributions of these miRNAs to the development of T2D, we detected the impacts of the candidate miRNAs on preadipocyte proliferation, insulin secretion by pancreatic β-cell, and glucose uptake by skeletal muscle cells. MAIN FINDINGS: Three miRNAs (miR-486, miR-146b and miR-15b), whose expression in the circulation was most dramatically augmented in obese children and adult T2D patients, were selected for further investigation. Of these 3 miRNAs, miR-486 was implicated in accelerating preadipocyte proliferation and myotube glucose intolerance, miR-146b and miR-15b were engaged in the suppression of high concentration glucose-induced pancreatic insulin secretion, and they all contributed to the pathological processes of obesity and T2D. PRINCIPAL CONCLUSIONS: Our results provide a better understanding of the role of circulating miRNAs, particularly miR-486, miR-146b and miR-15b, in predicting the future risk of T2D in obese children.

Long non-coding RNAs (lncRNAs) are involved in multiple cellular events, as well as in tumorigenesis. Colon cancer-associated transcript-1 (CCAT1) gene encodes an lncRNA whose over-activation was observed in an expanding list of primary human solid tumors and tumor cell lines, however its biological roles in acute myeloid leukaemia (AML) has not been reported yet at present. In this study, the aberrant upregulation of CCAT1 was detected in French-American-British M4 and M5 subtypes of adult AML patients. By gain- and loss-of-function analysis, we determined that CCAT1 repressed monocytic differentiation and promoted cell growth of HL-60 by sequestering tumor suppressive miR-155. Accordingly, a significant decrease in miR-155 level was detected in AML patients. Re-introduction of miR-155 into HL-60 cells restored monocytic maturation and repressed cell proliferation. Furthermore, CCAT1 could up-regulated c-Myc via its competing endogenous RNA (ceRNA) activity on miR-155. In conclusion, these results revealed new mechanism of lncRNA CCAT1 in AML development, and suggested that the manipulation of CCAT1 expression could serve as a potential strategy in AML therapy.

Esophageal squamous cell carcinoma (ESCC) is one of the leading causes of cancer-related death, especially in China. In addition, the prognosis of late stage patients is extremely poor. However, the biological significance of the long non-coding RNA lnc-ATB and its potential role in ESCC remain to be documented. In this study, we investigated the role of lnc-ATB and the underlying mechanism promoting its oncogenic activity in ESCC. Expression of lnc-ATB was higher in ESCC tissues and cell lines than that in normal counterparts. Upregulated lnc-ATB served as an independent prognosis predictor of ESCC patients. Moreover, loss-of-function assays in ESCC cells showed that knockdown of lnc-ATB inhibited cell proliferation and migration both in vitro and in vivo. Mechanistic investigation indicated that lnc-ATB exerted oncogenic activities via regulating Kindlin-2, as the anti-migration role of lnc-ATB silence was attenuated by ectopic expression of Kindlin-2. Further analysis showed that lnc-ATB functions as a molecular sponge for miR-200b and Kindlin-2. Dysregulated miR-200b/Kindlin-2 signaling mediated the oncogenic activity of lnc-ATB in ESCC. Our results suggest that lnc-ATB predicts poor prognosis and may serve as a potential therapeutic target for ESCC patients.

// Xiaoliang Wu 1, 2, * , Xiaoxiao Dinglin 3, * , Xing Wang 2, * , Wen Luo 1 , Qi Shen 1 , Yong Li 1 , Ling Gu 2, 4 , Qianghua Zhou 2 , Haotu Zhu 2 , Yanjie Li 5 , Chaodi Tan 6 , Xianzi Yang 7 and Zhenfeng Zhang 8, 2 1 Department of Oncology, Guizhou Provincial People’s Hospital, Guiyang, China 2 State Key Laboratory of Oncology in South China & Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China 3 Department of Medical Oncology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China 4 Puer University, Puer, China 5 The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China 6 Sun Yat-sen University, Guangzhou, China 7 Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, China 8 Department of Radiology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China * These authors have contributed equally to this work Correspondence to: Zhenfeng Zhang, email: zhangzhf@gzhmu.edu.cn Xianzi Yang, email: yangxz@mail2.sysu.edu.cn Keywords: long non-coding RNA, XIST, EZH2, esophageal squamous cell carcinoma, EMT Received: March 08, 2017      Accepted: May 22, 2017      Published: June 27, 2017 ABSTRACT The long non-coding RNA XIST is a long non-coding RNA that associates with polycomb repressive complex 2 to regulate X-chromosome inactivation in female mammals. The biological roles as well as the underlying mechanisms of XIST in esophageal squamous cell carcinoma remained yet to be solved. Our data indicated that XIST was significantly upregulated in esophageal squamous cancerous tissues and cancer cell lines, as compared with that in the corresponding non-cancerous tissues and immortalized normal squamous epithelial cells. High XIST expression predicted poor prognosis of esophageal squamous cancer patients. Lentivirus mediated knockdown of XIST inhibited proliferation, migration and invasion of esophageal squamous cancer cells in vitro and suppressed tumor growth in vivo . Knockdown of XIST resulted in elevated expression of miR-101 and decreased expression of EZH2. Further analysis showed that XIST functioned as the competitive endogenous RNA of miR-101 to regulate EZH2 expression. Moreover, enforced expression of EZH2 significantly attenuated the anti-proliferation activity upon XIST knockdown. Conclusively, XIST plays an important role in malignant progression of ESCC via modulation of miR-101/EZH2 axis.