RP11-616M22.7 recapitulates imatinib resistance in gastrointestinal stromal tumor.

Emerging evidence has shown that long non-coding RNAs (lncRNAs) play crucial roles in human cancers. However, systematic characterization of lncRNAs and their roles in gastrointestinal stromal tumor (GIST) therapy have been lacking. We performed high-throughput RNA sequencing (RNA-seq) of 20 GIST and paired adjacent normal samples. We characterized the transcriptional landscape and dysregulation of lncRNAs in GIST. We identified 866 upregulated and 1,268 downregulated lncRNAs in GIST samples, the majority of which were GIST-specific over other cancer types. Most hallmarks were found to be dysregulated in GIST samples, and lncRNAs were highly associated with cancer-related hallmarks. RP11-616M22.7 was identified to increase in imatinib-resistant samples compared to those in non-resistant samples. Further analysis revealed that RP11-616M22.7 was closely associated with the Hippo signaling pathway. By treating GIST cells with different doses of imatinib, we verified that RP11-616M22.7 knockdown promotes the sensitivity of tumor cells, whereas RP11-616M22.7 overexpression induces resistance to imatinib. We further confirmed reducing of resistance to imatinib by knocking down RP11-616M22.7 in vivo. Additionally, RP11-616M22.7 was observed to interact with RASSF1 protein. Our study revealed that deficiency of RP11-616M22.7 was able to reduce resistance of the GIST cell response to imatinib treatment both in vitro and in vivo.

Linc00423 as a tumor suppressor in retroperitoneal liposarcoma via activing MAPK signaling pathway through destabilizing of NFATC3.

Unraveling the noncoding RNA expression networks governing cancer initiation and development is essential while remains largely uncompleted in retroperitoneal liposarcoma (RLS). Through RNA-seq technologies and computational biology, deregulated long noncoding RNAs (lncRNAs) are being identified and reveal that lncRNAs are implicated in serial steps of RLS development. High-throughput sequencing with computational methods for assembling the transcriptome of five paired RLS patient's tissues. We found that long intergenic noncoding RNA 423 (linc00423) was downregulated in RLS tissues. Gain-of-function assays revealed that overexpressed linc00423 obviously inhibited RLS cell growth in vitro and in vivo. Additionally, RNA sequence, RNA-pulldown and RIP assays evidenced that linc00423 involved in MAPK signaling pathway via destabilizing of nuclear factor of activated T-cells 3 (NFATC3). Summing up, our findings demonstrated that linc00423 acted as the tumor suppressor in RLS cells through regulating the protein level of NFATC3 at a post-transcriptional level and negatively regulated the MAPK signaling pathway at a transcriptional level. Linc00423 might serve as a candidate prognostic biomarker and a target for novel therapies of RLS patients.

A novel long noncoding RNA PILRLS promote proliferation through TCL1A by activing MDM2 in Retroperitoneal liposarcoma.

It is becoming evident that lncRNAs may be an important class of pervasive genes involved in carcinogenesis and metastasis. However, the biological and molecular mechanisms of lncRNAs in retroperitoneal liposarcoma have never been reported. In our study, we found a novel lncRNA PILRLS (Proliferation Interacting LncRNA in Retroperitoneal Liposarcoma), which as an oncogene significantly overexpressed in retroperitoneal liposarcoma. Functions of PILRLS on tumor progression both in vitro and in vivo have verified in this study which PILRLS knockdown significantly inhibited cell proliferation and colony formation. RNA pull-down assay found PILRLS can specific binding with TCL1A which also regulate the expression level of TCL1A. Our work for the first time demonstrated PILRLS can activating the MDM2 by binding with TCL1A which suppress the P53 pathway to promote the unlimited growth of retroperitoneal Liposarcoma cells. It suggests that PILRLS may be an important targets for retroperitoneal liposarcoma therapy.

Long non-coding RNA CRNDE promotes gallbladder carcinoma carcinogenesis and as a scaffold of DMBT1 and C-IAP1 complexes to activating PI3K-AKT pathway.

Deleted in malignant brain tumors 1 (DMBT1) is deleted during cancer progression and as a potential tumor-suppressor gene in various types of cancer. However, its role in Gallbladder cancer remains poorly understood. DMBT1 has low-expression and deletion of copy number were detected in normal tissues and GBC cancer tissues by qRT-PCR. Knockdown of DMBT1 increased migration and invasion and overexpressed DMBT1 impaired migration and invasion in GBC cells. We also evaluated the molecular mechanism of DMBT1 by RNA sequencing and GSEA analysis. RNA-Pulldown and RIP assay authenticated CRNDE can specified binding with DMBT1 and c-IAP1. Downregulation of DMBT1 resulted in significant change of gene expression (at least 2-fold) in PI3K-AKT pathway, increased expression of MMP-9, JUK-1, ERK and AKT, activating PI3K-AKT pathway lead to GBC carcinogenesis.We for the first time reported, DMBT1 as a prognosis biomarker, is low-expressed in GBC tumors, and CRNDE act as a scaffold to recruit the DMBT1 and c-IAP1, promotes the PI3K-AKT pathway. Our study reveals DMBT1 may be an important contributor to GBC cancer development.

HDAC1 promoted migration and invasion binding with TCF12 by promoting EMT progress in gallbladder cancer.

The identification of prognostic markers for gallbladder cancer is needed for clinical practice. Histone deacetylases (HDACs) play an important role in tumor development and progression by modifying histone and non-histone proteins. However, the expression of HDAC1 in patients with gallbladder cancer is still unknown. Here, we reported that HDAC1 expression was elevated in cancerous tissue and correlated with lymph node metastasis and poorer overall survival in patients with GBC. Knockdown of HDAC1 using lentivirus delivery of HDAC1-specific shRNA abrogated the migration and invasion of GBC cells in vitro. TCF-12, as the HDAC1 binding protein, has also correlates with poor prognosis in GBC patients. And there is a positive correlation between HDAC1 and TCF-12 which leading the high invasion and migration ability of GBC cells. Taken together, our data suggested that HDAC1 and TCF-12 are a potential prognostic maker and may be a molecular target for inhibiting invasion and metastasis in GBC.

LIN28B suppresses microRNA let-7b expression to promote CD44+/LIN28B+ human pancreatic cancer stem cell proliferation and invasion.

Although the highly proliferative, migratory, and multi-drug resistant phenotype of human pancreatic cancer stem cells (PCSCs) is well characterized, knowledge of their biological mechanisms is limited. We used CD44 and LIN28B as markers to screen, isolate, and enrich CSCs from human primary pancreatic cancer. Using flow cytometry, we identified a human primary pancreatic cancer cell (PCC) subpopulation expressing high levels of both CD44 and LIN28B. CD44+/LIN28B+ PCSCs expressed high levels of stemness marker genes and possessed higher migratory and invasive ability than CD44-/LIN28B- PCCs. CD44+/LIN28B+ PCSCs were more resistant to growth inhibition induced by the chemotherapeutic drugs cisplatin and gemcitabine hydrochloride, and readily established tumors in vivo in a relatively short time. Moreover, microarray analysis revealed significant differences between the cDNA expression patterns of CD44+/LIN28B+ PCSCs and CD44-/LIN28B- PCCs. Following siRNA interference of endogenous LIN28B gene expression in CD44+/LIN28B+ PCSCs, not only was their proliferation decreased, there was also cell cycle arrest due to suppression of cyclin D1 expression following the stimulation of miRNA let-7b expression. In conclusion, CD44+/LIN28B+ cells, which possess CSC characteristics, can be reliably sorted from human primary PCCs and represent a valuable model for studying cancer cell physiology and multi-drug resistance.

PDK1 induces JunB, EMT, cell migration and invasion in human gallbladder cancer.

The protein 3-phosphoinositide-dependent protein kinase 1 (PDK1) is upregulated in cancer. Here we showed that PDK1 stimulated cell proliferation, invasion and metastasis in gallbladder cancer (GBC), by inducing JunB and epithelial-mesenchymal transition. JunB levels were increased in GBC samples and positively correlated with PDK1 levels in tumors. High levels of JunB predicted poor overall survival in GBC patients. Thus, PDK1 functions as a tumor promoter in human GBC by upregulating JunB.

Expression profile of microRNAs in gastrointestinal stromal tumors revealed by high throughput quantitative RT-PCR microarray.

AIM: To investigate the microRNA (miRNA) expression profile in gastrointestinal stromal tumor (GIST) tissues that could serve as a novel diagnostic biomarker for GIST detection. METHODS: We performed a quantitative real-time quantitative reverse transcriptase polymerase chain reaction assay to analyze the expression of 1888 miRNAs in a sample set that included 54 GIST tissue samples. RESULTS: We found that dysregulation of several miRNAs may be related to the malignant potential of GISTs. Six of these miRNAs, hsa-let-7c, miR-218, miR-488#, miR-4683, miR-34c-5p and miR-4773, were selected as the final list of biomarkers to separate the malignant GISTs (M group) from the benign GISTs (B group). In addition, MiR-29b-2#, hsa-let-7c, miR-891b, miR-218, miR-204, miR-204-3p, miR-628-5p, miR-744, miR-29c#, miR-625 and miR-196a were used to distinguish between the borderline (BO group) and M groups. There were 11 common miRNAs selected to separate the benign and borderline (BB) group from the M group, including hsa-let-7c, miR-218, miR-628-5p, miR-204-3p, miR-204, miR-891b, miR-488#, miR-145, miR-891a, miR-34c-5p and miR-196a. CONCLUSION: The identified miRNAs appear to be novel biomarkers to distinguish malignant from benign GISTs, which may be helpful to understand the mechanisms of GIST oncogenesis and progression, and to further elucidate the characteristics of GIST subtypes.

Liposarcoma miRNA signatures identified from genome-wide miRNA expression profiling.

AIMS: To identify the miRNA expression profile of liposarcoma (LPS) that could facilitate detection of LPS, and provide the basis for further investigation of molecular-targeted therapeutic drugs. MATERIALS & METHODS: A real-time quantitative PCR assay was performed to analyze the expression of 1888 miRNAs from 25 LPS tumor tissue samples, 16 samples of adipose tissue adjacent to the tumors and 18 normal adipose tissue samples from patients with LPS. RESULTS: Ten dysregulated miRNAs were identified that effectively distinguished LPS tissue from adipose tissue and benign lipoma tissue, and LPS tumor tissues from normal adipose tissues in LPS patients. Furthermore, the expression profiles of miRNAs could also classify the subtype of LPS. CONCLUSION: The identified miRNAs appear to be novel biomarkers for the detection of LPS, and may contribute to an understanding of the mechanisms of LPS tumorigenesis and its development, and further elucidate the characteristics of LPS subtypes.

Prognostic implications of SLIT and ROBO1 expression in gallbladder cancer.

SLIT, a secretory glycoprotein, and its receptor roundabout (ROBO) are expressed in several types of cancer and have been implicated in tumor angiogenesis. The purpose of this study was to determine the prognostic implications of SLIT and ROBO1 expression and their association with clinicopathologic characteristics in gallbladder cancer. A retrospective analysis of 109 consecutive patients who underwent primary gallbladder cancer resection was conducted. Univariate and multivariate models were used to analyze the effect of clinicopathologic factors on survival. Expression of SLIT and ROBO1 was evaluated by immunohistochemistry, and their association with clinicopathologic characteristics was analyzed using mean testing. Multivariate linear regression analysis was also applied to investigate the independent predictors of ROBO1 expression. Seventy-five patients were included in the post-resection survival analysis, with 1-year and 3-year overall survival rates of 60 and 40 %, respectively. Univariate analysis revealed that pN classification, pT classification, pM classification, liver involvement, perineural invasion, TNM staging, Nevin staging, and microscopic resection margins affect prognosis. Multivariate analysis confirmed that pN classification, liver involvement, and perineural invasion are independent prognostic factors. In the mean tests of 109 cases, the mean difference of SLIT immunoreactivity was significant according to the presence of gallstones (P = 0.003) and liver involvement (P = 0.005), while the mean difference of ROBO1 immunoreactivity was significant according to liver involvement (P < 0.001), TNM staging (P < 0.001), and Nevin staging (P < 0.001). Multivariate analysis of ROBO1 immunoreactivity showed that SLIT immunoreactivity and TNM stage (adjusted R (2) = 0.203) or SLIT immunoreactivity and Nevin stage (adjusted R (2) = 0.195) were independent predictors of ROBO1 expression. pN classification, liver involvement, perineural invasion, and pathologic stage are significant prognostic factors for gallbladder cancer survival. SLIT expression is associated with cholelithiasis and liver involvement, and ROBO1 expression is associated with liver involvement and pathologic stage. In addition, SLIT expression and pathologic stage predict ROBO1 expression independently.