BackgroundThe human genome encodes many long non-coding RNAs (lncRNAs). However, their biological functions, molecular mechanisms, and the prognostic value associated with pancreatic ductal adenocarcinoma (PDAC) remain to be elucidated. Here, we identify a fundamental role for the lncRNA HOXA transcript at the distal tip (HOTTIP) in the progression and chemoresistance of PDAC.MethodsHigh-throughput microarrays were performed to detect the expression profiles of lncRNAs and messenger RNAs in eight human PDAC tissues and four pancreatic tissues. Quantitative real-time PCR was used to determine the levels of HOTTIP and HOXA13 transcripts in PDAC cell lines and 90 PDAC samples from patients. HPDE6 cells (immortalized human pancreatic ductal epithelial cells) and corresponding adjacent non-neoplastic tissues were used as controls, respectively. The functions of HOTTIP and HOXA13 in cell proliferation, invasion, and epithelial-mesenchymal transition were evaluated by targeted knockdown in vitro. CCK-8 assays, colony formation assays, and xenografts in nude mice were used to investigate whether targeted silencing of HOTTIP could sensitize pancreatic cancer cells to gemcitabine. Immunohistochemistry was performed to investigate the relationship between HOXA13 expression and patient outcome.ResultsMicroarray analyses revealed that HOTTIP was one of the most significantly upregulated lncRNAs in PDAC tissues compared with pancreatic tissues. Quantitative PCR further verified that HOTTIP levels were increased in PDAC cell lines and patient samples compared with controls. Functionally, HOTTIP silencing resulted in proliferation arrest by altering cell-cycle progression, and impaired cell invasion by inhibiting epithelial-mesenchymal transition in pancreatic cancer. Additionally, inhibition of HOTTIP potentiated the antitumor effects of gemcitabine in vitro and in vivo. Furthermore, knockdown of HOXA13 by RNA interference (siHOXA13) revealed that HOTTIP promoted PDAC cell proliferation, invasion, and chemoresistance, at least partly through regulating HOXA13. Immunohistochemistry results revealed that higher HOXA13 expression was correlated with lymph node metastasis, poor histological differentiation, and decreased overall survival in PDAC patients.ConclusionsAs a crucial tumor promoter, HOTTIP promotes cell proliferation, invasion, and chemoresistance by modulating HOXA13. Therefore, the HOTTIP/HOXA13 axis is a potential therapeutic target and molecular biomarker for PDAC.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-015-0442-z) contains supplementary material, which is available to authorized users.

Purpose: Golgi phosphoprotein 3 (GOLPH3) has been reported to be involved in various biologic processes. The clinical significance and biologic role of GOLPH3 in breast cancer, however, remains unknown.Experimental Design: Expression of GOLPH3 in normal breast cells, breast cancer cells, and 6-paired breast cancer and adjacent noncancerous tissues were quantified using real-time PCR and Western blotting. GOLPH3 protein expression was analyzed in 258 archived, paraffin-embedded breast cancer samples using immunohistochemistry. The role of GOLPH3 in breast cancer cell proliferation and tumorigenicity was explored in vitro and in vivo. Western blotting and luciferase reporter analyses were used to investigate the effect of GOLPH3 overexpression and silencing on the expression of cell-cycle regulators and FOXO1 transcriptional activity.Results: GOLPH3 was significantly upregulated in breast cancer cells and tissues compared with normal cells and tissues. Immunohistochemical analysis revealed high expression of GOLPH3 in 133 of 258 (51.6%) breast cancer specimens. Statistical analysis showed a significant correlation of GOLPH3 expression with advanced clinical stage and poorer survival. Overexpression and ablation of GOLPH3 promoted and inhibited, respectively, the proliferation and tumorigenicity of breast cancer cells in vitro and in vivo. GOLPH3 overexpression enhanced AKT activity and decreased FOXO1 transcriptional activity, downregulated cyclin-dependent kinase (CDK) inhibitor p21Cip1 , p27 Kip1, and p57 Kip2 , and upregulated the CDK regulator cyclin D1. Conclusion: Our results suggest that high GOLPH3 expression is associated with poor overall survival in patients with breast cancer and that GOLPH3 overexpression increases the proliferation and tumorigenicity of human breast cancer cells. Clin Cancer Res; 18(15); 4059-69. Ó2012 AACR.

FOXO transcription factors are key tumor suppressors in mammalian cells. Until now, suppression of FOXOs in cancer cells was thought to be mainly due to activation of multiple onco-kinases by a phosphorylation-ubiquitylation-mediated cascade. Therefore, it was speculated that inhibition of FOXO proteins would naturally occur through a multiple step post-translational process. However, whether cancer cells may downregulate FOXO protein via an alternative regulatory mechanism is unclear. In the current study, we report that expression of miR-96 was markedly upregulated in breast cancer cells and breast cancer tissues compared with normal breast epithelial cells (NBEC) and normal breast tissues. Ectopic expression of miR-96 induced the proliferation and anchorage-independent growth of breast cancer cells, while inhibition of miR-96 reduced this effect. Furthermore, upregulation of miR-96 in breast cancer cells resulted in modulation of their entry into the G1/S transitional phase, which was caused by downregulation of cyclin-dependent kinase (CDK) inhibitors, p27Kip1 and p21Cip1, and upregulation of the cell-cycle regulator cyclin D1. Moreover, we demonstrated that miR-96 downregulated FOXO3a expression by directly targeting the FOXO3a 3′-untranslated region. Taken together, our results suggest that miR-96 may play an important role in promoting proliferation of human breast cancer cells and present a novel mechanism of miRNA-mediated direct suppression of FOXO3a expression in cancer cells.

BackgroundThe communication between carcinoma associated fibroblasts (CAFs) and cancer cells facilitate tumor metastasis. In this study, we further underlying the epigenetic mechanisms of CAFs feed the cancer cells and the molecular mediators involved in these processes.MethodsMCF-7 and MDA-MB-231 cells were treated with CAFs culture conditioned medium, respectively. Cytokine antibody array, enzyme-linked immunosorbent assay, western blotting and immunofluorescence were used to identify the key chemokines. Chromatin immunoprecipitation and luciferase reporter assay were performed to explore the transactivation of target LncRNA by CAFs. A series of in vitro assays was performed with RNAi-mediated knockdown to elucidate the function of LncRNA. An orthotopic mouse model of MDA-MB-231 was conducted to confirm the mechanism in vivo.ResultsHere we reported that TGF-β1 was top one highest level of cytokine secreted by CAFs as revealed by cytokine antibody array. Paracrine TGF-β1 was essential for CAFs induced EMT and metastasis in breast cancer cells, which is a crucial mediator of the interaction between stromal and cancer cells. CAF-CM significantly enhanced the HOTAIR expression to promote EMT, whereas treatment with small-molecule inhibitors of TGF-β1 attenuated the activation of HOTAIR. Most importantly, SMAD2/3/4 directly bound the promoter site of HOTAIR, located between nucleotides -386 and -398, -440 and -452, suggesting that HOTAIR was a directly transcriptional target of SMAD2/3/4. Additionally, CAFs mediated EMT by targeting CDK5 signaling through H3K27 tri-methylation. Depletion of HOTAIR inhibited CAFs-induced tumor growth and lung metastasis in MDA-MB-231 orthotopic animal model.ConclusionsOur findings demonstrated that CAFs promoted the metastatic activity of breast cancer cells by activating the transcription of HOTAIR via TGF-β1 secretion, supporting the pursuit of the TGF-β1/HOTAIR axis as a target in breast cancer treatment.Electronic supplementary materialThe online version of this article (10.1186/s12943-018-0758-4) contains supplementary material, which is available to authorized users.