Competing interests C.J.D. is on the Scientific Advisory Board of Mirati Therapeutics. A.C.K. has financial interests in Vescor Therapeutics, LLC. A.C.K. is an inventor on patents pertaining to KRAS-regulated metabolic pathways, redox control pathways in pancreatic cancer, targeting GOT1 as a therapeutic approach, and the autophagic control of iron metabolism. A.C.K. is on the Scientific Advisory Board of Cornerstone/Rafael Pharmaceuticals.

Esophageal squamous cell carcinoma (ESCC) is the main subtype of esophageal cancer. Long noncoding RNAs (lncRNAs) are thought to play a critical role in cancer development. Recently, lncRNA CASC9 was shown to be dysregulated in many cancer types, but the mechanisms whereby this occurs remain largely unknown. In this study, we found that CASC9 was significantly upregulated in ESCC tissues, with further analysis revealing that elevated CASC9 expression was associated with ESCC prognosis and metastasis. Furthermore, we found that CASC9 knockdown significantly repressed ESCC migration and invasion in vitro and metastasis in nude mice in vivo. A microarray analysis and mechanical experiments indicated that CASC9 preferentially affected gene expression linked to ECM–integrin interactions, including LAMC2, an upstream inducer of the integrin pathway. We demonstrated that LAMC2 was consistently upregulated in ESCC and promoted ESCC metastasis. LAMC2 overexpression partially compromised the decrease of cell migration and invasion capacity in CASC9 knockdowns. In addition, we found that both CASC9 and LAMC2 depletion reduced the phosphorylation of FAK, PI3K, and Akt, which are downstream effectors of the integrin pathway. Moreover, the reduction in phosphorylation caused by CASC9 depletion was rescued by LAMC2 overexpression, further confirming that CASC9 exerts a pro-metastatic role through LAMC2. Mechanistically, RNA pull-down and RNA-binding protein immunoprecipitation (RIP) assay indicated that CASC9 could bind with the transcriptional coactivator CREB-binding protein (CBP) in the nucleus. Chromatin immunoprecipitation (ChIP) assay additionally illustrated that CASC9 increased the enrichment of CBP and H3K27 acetylation in the LAMC2 promoter, thereby upregulating LAMC2 expression. In conclusion, we demonstrate that CASC9 upregulates LAMC2 expression by binding with CBP and modifying histone acetylation. Our research reveals the prognostic and pro-metastatic roles for CASC9 in ESCC, suggesting that CASC9 could serve as a biomarker for prognosis and a target for metastasis treatment.

BackgroundAbnormal expression of numerous long non-coding RNAs (lncRNAs) has been reported in esophageal squamous cell carcinoma (ESCC) recently, but the great majority of their roles and mechanisms remain largely unclear. We aim to identify the critical ESCC-associated lncRNAs and elucidate the functions and mechanisms in detail.MethodsMicroarrays were used to analyze the differentially expressed lncRNAs in ESCC tissues. qRT-PCR was used to verify the result of microarrays. The effects of the most up-regulated lncRNA, cancer susceptibility candidate 9(CASC9), on cell growth, proliferation and cell cycle were investigated by in vivo and in vitro assays. Microarrays and recovery tests were used to discover the regulatory targets of CASC9. RNA FISH and subcellular fractionation assays were used to detect the subcellular location of CASC9. Finally, the mechanism of CASC9 regulating PDCD4 was explored by RIP, RNA-protein pull down and ChIP assays.ResultsESCC tissue microarrays showed that CASC9 was the most up-regulated lncRNA. qRT-PCR analysis indicated that CASC9 expression was positively associated with tumor size and TNM stage, and predicted poor overall survival of ESCC patients. Knockdown of CASC9 inhibited ESCC cell growth in vitro and tumorigenesis in nude mice. Furthermore interfering CASC9 decreased cell proliferation and blocked cell cycle G1/S transition. CASC9-associated microarrays indicated that PDCD4 might be the target of CASC9. Consistent with this, PDCD4 expression was negatively associated with CASC9 expression in ESCC tissues and predicted good prognosis. Manipulating CASC9 expression in ESCC cells altered both PDCD4 mRNA and protein levels and cell cycle arrest caused by CASC9 knockdown could be rescued by suppressing PDCD4 expression. CASC9 located both in the nucleus and cytoplasm. Mechanistically, enhancer of zeste homolog2 (EZH2) could bind to both CASC9 and PDCD4 promoter region. Interfering CASC9 reduced the enrichment of EZH2 and H3K27me3 in the PDCD4 promoter region.ConclusionsOur study firstly demonstrates that lncRNA CASC9 functions as an oncogene by negatively regulating PDCD4 expression through recruiting EZH2 and subsequently altering H3K27me3 level. Our study implicates lncRNA CASC9 as a valuable biomarker for ESCC diagnosis and prognosis.Electronic supplementary materialThe online version of this article (10.1186/s12943-017-0715-7) contains supplementary material, which is available to authorized users.

Summary Pancreatic ductal adenocarcinoma (PDAC) remains recalcitrant to all forms of cancer treatment and carries a dismal 5-year survival rate of 8% 1 . Inhibition of oncogenic KRAS (hereafter KRAS*), the earliest lesion in disease development that is present in >90% of PDAC, and its signaling surrogates has yielded encouraging preclinical results with experimental agents 2 - 4 . However, KRAS*-independent disease recurrence following genetic extinction of Kras* in mouse models anticipates the need for co-extinction strategies 5 , 6 . Multiple oncogenic processes are initiated at the cell surface, where KRAS* physically and functionally interacts to direct signaling essential for malignant transformation and tumor maintenance. Insights into the complexity of the functional surfaceome have been technologically limited until recently, and, in the case of PDAC, the genetic control of the function and composition of the PDAC surfaceome in the context of KRAS* signaling remains largely unexplored. Here, we developed an unbiased, functional target discovery platform to query KRAS*-dependent changes of the PDAC surfaceome, which uncovered syndecan-1 (SDC1) as a protein upregulated at the cell surface by KRAS*. Cell surface localization of SDC1 is essential for disease maintenance and progression, where it regulates macropinocytosis, an essential metabolic pathway that fuels PDAC cell growth. Thus, our study forges a mechanistic link between KRAS* signaling and a targetable molecule driving nutrient salvage pathways in PDAC and validates oncogene-driven surfaceome annotation as a strategy to identify cancer-specific vulnerabilities.

Esophageal cancer is one of the leading causes of cancer-related mortality because of poor prognosis. Long noncoding RNAs (lncRNAs) have been gradually demonstrated to play critical roles in cancer development. We identified a novel long noncoding RNA named linc00460 by microarray analysis using esophageal squamous cell carcinoma (ESCC) clinical samples, which has not been studied before. Our research indicated that linc00460 was overexpressed in the majority of tumor tissues and ESCC cell lines. Linc00460 expression was positively correlated with ESCC TNM stage, lymph node metastasis, and predicted poor prognosis. In vitro experiments showed that linc00460 depletion suppressed ESCC cell growth through regulating cell proliferation and cell cycle; in additional, linc00460 depletion accelerated ESCC cell apoptosis. We further revealed that linc00460 overexpression was manipulated by transcriptional co-activator CBP/P300 through histone acetylation. Given the high expression and important biological functions of linc00460, we suggest that linc00460 works as an oncogene and might be a valuable prognostic biomarker for ESCC diagnosis and treatment.

Cancer stem cells/cancer-initiating cells (CICs) and their microenvironmental niche play a vital role in malignant tumour recurrence and metastasis. Cancer-associated fibroblasts (CAFs) are major components of the niche of breast cancer-initiating cells (BCICs), and their interactions may profoundly affect breast cancer progression. Autophagy has been considered to be a critical process for CIC maintenance, but whether it is involved in the cross-talk between CAFs and CICs to affect tumourigenesis and pathological significance has not been determined. In this study, we found that the presence of CAFs containing high levels of microtubule-associated protein 1 light chain 3 (LC3II), a marker of autophagosomes, was associated with more aggressive luminal human breast cancer. CAFs in human luminal breast cancer tissues with high autophagy activity enriched BCICs with increased tumourigenicity. Mechanistically, autophagic CAFs released high-mobility group box 1 (HMGB1), which activated its receptor, Toll-like receptor (TLR) 4, expressed by luminal breast cancer cells, to enhance their stemness and tumourigenicity. Furthermore, immunohistochemistry of 180 luminal breast cancers revealed that high LC3II/TLR4 levels predicted an increased relapse rate and a poorer prognosis. Our findings demonstrate that autophagic CAFs play a critical role in promoting the progression of luminal breast cancer through an HMGB1-TLR4 axis, and that both autophagy in CAFs and TLR4 on breast cancer cells constitute potential therapeutic targets. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal cancers, with a five-year survival rate of around 5% to 8%. To date, very few available drugs have been successfully used to treat PDAC due to the poor understanding of the tumor-specific features. One of the hallmarks of pancreatic cancer cells is the deregulated cellular energetics characterized by the “Warburg effect”. It has been known for decades that cancer cells have a dramatically increased glycolytic flux even in the presence of oxygen and normal mitochondrial function. Glycolytic flux is the central carbon metabolism process in all cells, which not only produces adenosine triphosphate (ATP) but also provides biomass for anabolic processes that support cell proliferation. Expression levels of glucose transporters and rate-limiting enzymes regulate the rate of glycolytic flux. Intermediates that branch out from glycolysis are responsible for redox homeostasis, glycosylation, and biosynthesis. Beyond enhanced glycolytic flux, pancreatic cancer cells activate nutrient salvage pathways, which includes autophagy and micropinocytosis, from which the generated sugars, amino acids, and fatty acids are used to buffer the stresses induced by nutrient deprivation. Further, PDAC is characterized by extensive metabolic crosstalk between tumor cells and cells in the tumor microenvironment (TME). In this review, we will give an overview on recent progresses made in understanding glucose metabolism-related deregulations in PDAC.

Long noncoding RNA (lncRNA) is yet to be linked to cancer metabolism. Here, we report that upregulation of the lncRNA () promotes glycolysis, cell proliferation, and tumor growth in breast cancer. YIYA is associated with the cytosolic cyclin-dependent kinase CDK6 and regulated CDK6-dependent phosphorylation of the fructose bisphosphatase PFK2 (PFKFB3) in a cell-cycle-independent manner. In breast cancer cells, these events promoted catalysis of glucose 6-phosphate to fructose-2,6-bisphosphate/fructose-1,6-bisphosphate. CRISPR/Cas9-mediated deletion of or CDK6 silencing impaired glycolysis and tumor growth In clinical specimens of breast cancer, was expressed in approximately 40% of cases where it correlated with CDK6 expression and unfavorable survival outcomes. Our results define a functional role for lncRNA in metabolic reprogramming in cancer, with potential clinical implications for its therapeutic targeting. These findings offer a first glimpse into how a long-coding RNA influences cancer metabolism to drive tumor growth. .