HOXA Transcript At The Distal Tip Expression Research Articles

LncRNA HOTTIP regulates TLR4 promoter methylation by recruiting H3K4 methyltransferase MLL1 to affect apoptosis and inflammatory response of fibroblast-like synoviocyte in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease, and the role of HOXA transcript at the distal tip (HOTTIP) in its pathogenesis remains underexplored. This study investigates the mechanism by which HOTTIP influences apoptosis and the inflammatory response of fibroblast-like synoviocytes (FLS). An RA mouse model was established, and clinical scores were analyzed. Pathological changes in synovial tissues, bone mineral density (BMD) of the paws, serum tartrate-resistant acid phosphatase (TRAP) activity, and TNF-α and IL-1β levels were assessed. FLS were transfected, and cell proliferation and apoptosis were examined. The RNA-pull-down assay determined HOTTIP's interaction with mixed-lineage leukemia 1 (MLL1), while RNA immunoprecipitation assay measured HOTTIP expression pulled down by MLL1. The levels of MLL1 and toll-like receptor 4 (TLR4) after MLL1 overexpression based on HOTTIP silencing were determined. Chromatin immunoprecipitation (ChIP) was performed with H3K4me3 as an antibody, followed by the evaluation of TLR4 expression. HOTTIP expression was elevated in RA mouse synovial tissues. Inhibition of HOTTIP led to reduced clinical scores, inflammatory infiltration, synovial hyperplasia, TRAP activity, and TNF-α and IL-1β levels, along with increased BMD. In vitro Interference with HOTTIP suppressed RA-FLS apoptosis and inflammation. HOTTIP upregulated TLR4 expression by recruiting MLL1 to facilitate TLR4 promoter methylation. MLL1 overexpression reversed HOTTIP silencing-mediated repression of RA-FLS apoptosis. Activation of H3K4 methylation counteracted HOTTIP knockout, ameliorating the inflammatory response. HOTTIP regulates TLR4 expression by recruiting MLL1, leading to TLR4 promoter methylation, thereby suppressing RA-FLS proliferation and inducing cell apoptosis and inflammatory response in RA.

Long-noncoding RNA HOXA transcript at the distal tip ameliorates the insulin resistance and hepatic gluconeogenesis in mice with gestational diabetes mellitus via the microRNA-423-5p/wingless-type MMTV integration site family member 7A axis

ABSTRACT Long-noncoding RNA HOXA transcript at the distal tip (HOTTIP) has been probed to exert essential effects on diabetes progression, while its function in gestational diabetes mellitus (GDM) remains unclear. This study was committed to unravel the effects of HOTTIP on GDM progression via the microRNA (miR)-423-5p/wingless-type MMTV integration site family member 7A (WNT7A) axis. The GDM mouse model was established. HOTTIP, miR-423-5p and WNT7A levels in GDM mice were examined. The saline with dissolved various constructs altering HOTTIP, miR-423-5p and WNT7A expression was injected into GDM mice to detect the levels of GDM‐related biochemical indices, HOMA indices, liver gluconease: expression levels of phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G-6-Pase), glucose transporter 2 (GLUT2) and pathological changes of pancreatic tissues, and the apoptosis rate of pancreatic cells in GDM mice. The relations among HOTTIP, miR-423-5p and WNT7A were validated. HOTTIP and WNT7A levels were decreased while miR-423-5p was elevated in GDM mice. The enriched HOTTIP or silenced miR-423-5p alleviated the levels of GDM‐relatedbiochemical indices, enhanced the insulin homeostasis, elevated GLUT2 expression and decreased G-6-pase and PEPCK expression, mitigated the pathological changes of pancreatic tissues, and hindered the apoptosis of pancreatic cells. MiR-143-5p upregulation abrogated the effects of elevated HOTTIP on repressing GDM; whereas WNT7A deletion reversed the therapeutic effects of reduced miR-423-5p. HOTTIP sponged miR-423-5p that targeted WNT7A. HOTTIP ameliorates insulin resistance and hepatic gluconeogenesis in GDM mice via the modulation of the miR-423-5p/WNT7A axis. This study affords novel therapeutic modalities for GDM treatment.

The Influence of rs1859168 Polymorphism on Serum Expression of HOTTIP and Its Target miR-615-3p in Egyptian Patients with Breast Cancer.

Background: Polymorphisms of long noncoding RNAs are lately documented as hazardous factors for the development of numerous tumors. Furthermore, the evaluation of noncoding RNAs has emerged as a novel detector of breast cancer patients. We aimed to genotype the HOXA transcript at the distal tip (HOTTIP) rs1859168 and assess its relationship with the levels of the serum HOTTIP and its target miR-615-3p in patients with breast cancer (BC). Methods: One hundred and fifty-one patients with BC, 139 patients with fibroadenoma (FA), and 143 healthy participants were incorporated into the current study. The genotyping of rs1859168 and the measurements of the HOTTIP and miR-615-3p levels were assessed using quantitative real-time PCR. Results: We revealed a significant association between each of the CC genotypes, C allele, dominant and recessive models, and the increased risk of BC (p = 0.013, p < 0.001, p < 0.001, and p < 0.001, respectively) relative to the healthy controls. Similarly, the CC genotype, C allele, and recessive model were observed to be related to the increased incidence of BC with respect to FA (p < 0.001 for all). A significant upregulation of HOTTIP and a marked decrease of miR-615-3p were verified in patients with BC compared to each of the healthy individuals, patients with FA, and the non-BC group (healthy subjects + FA) (p < 0.001 for all). A significant negative correlation was demonstrated between the expression of HOTTIP and miR-615-3p in the serum of patients with BC. The HOTTIP expression was upregulated, while that of miR-615-3p was downregulated in patients with BC who carried the CC genotype with respect to those who carried the AA or AC genotypes (p < 0.05 for all). Conclusions: The genetic variants of rs1859168 are linked to an increased susceptibility to BC. Moreover, HOTTIP and miR-615-3p may be used as novel indicators and targets for the treatment of patients with BC.

Knockdown of lncRNA HOTTIP Inhibits Retinoblastoma Progression by Modulating the miR-101-3p/STC1 Axis.

Objective:Retinoblastoma (RB) is a frequent eye cancer in children. Long non-coding RNA (LncRNA) HOXA transcript at the distal tip (HOTTIP) is aberrantly expressed in cancer tissues. This study explores the underlying mechanism of lncRNA HOTTIP in RB.Methods:HOTTIP expression in normal retinal cells and RB cell lines was detected using qRT-PCR. The proliferation of RB cells was measured using CCK-8 and EdU assays, and apoptosis was detected using flow cytometry and Western blotting after the transfection of si-HOTTIP into Y79 cells and pc-HOTTIP into HXO-RB-44 cells. The target relationships between HOTTIP and miR-101-3p, and miR-101-3p and STC1 were predicted by bioinformatics website and verified using dual-luciferase reporter gene assay. The binding of HOTTIP and miR-101-3p was verified using RNA pull-down assay. STC1 mRNA and protein in RB cells were measured using qRT-PCR and Western blotting. Moreover, si-HOTTIP and in-miR-101-3p/in-NC, and si-HOTTIP and pc-STC1/pcDNA were co-transfected into Y79 cells respectively to evaluate cell proliferation and apoptosis. Xenograft study was conducted, and Ki67-positive expression was detected using immunohistochemical staining.Results:HOTTIP expression was promoted in RB tissues and cells. Downregulation of HOTTIP inhibited proliferation and promoted apoptosis of Y79 cells, while upregulation of HOTTIP promoted proliferation and inhibited apoptosis of HXO-RB-44 cells. There were target relationships between HOTTIP and miR-101-3p, and miR-101-3p and STC1. Inhibition of miR-101-3p or overexpression of STC1 reversed the effect of si-HOTTIP on the proliferation and apoptosis of RB cells. Xenograft study showed that knockdown of HOTTIP suppressed the growth of RB in vitro.Conclusion:It could be concluded that HOTTIP sponged miR-101-3p to upregulate STC1 expression, thereby promoting RB cell proliferation and inhibiting apoptosis.

Long Noncoding RNA HOTTIP Serves as an Independent Predictive Biomarker for the Prognosis of Patients with Clear Cell Renal Cell Carcinoma.

Several studies have indicated that HOXA transcript at the distal tip (HOTTIP) play important roles in the tumorigenesis and development of various cancers. We aim to investigate the expression and prognostic value of HOTTIP in clear cell renal cell carcinoma (ccRCC). A systematic review of PubMed, Embase, Medline, and Web of Science databases was performed to select eligible literatures relevant to the correlation between HOTTIP expression and clinical outcome of different cancers. The association between the HOTTIP level and overall survival (OS), lymph node metastasis (LNM), or clinical stage was subsequently analyzed. Survival analyses were performed in a large cohort of more than 500 patients with ccRCC from The Cancer Genome Atlas (TCGA) using bioinformatic methods. Seventeen studies with a total of 1594 patients with thirteen kinds of carcinomas were included in this analysis. The result showed that high HOTTIP expression could predict worse outcome in cancer patients, with the pooled hazard ratio (HR) of 2.34 (95% confidence interval (CI) 1.96–2.79, p < 0.0001). The result also showed that elevated HOTTIP expression was correlated with more LNM (OR = 2.61, 95% CI 1.91-3.58, p < 0.0001) and advanced clinical stage (OR = 3.57, 95% CI 2.58-4.93, p < 0.0001). We further validated that ccRCC patients with higher HOTTIP expression tend to have unsatisfactory outcomes both in the entire TCGA dataset and different clinical stratums, like age, grade, and stage. The tumor of those patients was associated with a larger size, easier to metastasis, advanced clinical stage, and a higher pathological grade. These findings suggested that increased HOTTIP expression might act as a novel prognostic marker for ccRCC patients.

HOTTIP Predicts Poor Survival in Gastric Cancer Patients and Contributes to Cisplatin Resistance by Sponging miR-216a-5p.

Gastric cancer (GC) is a significant public health burden worldwide, and cisplatin resistance is the leading cause for the failure of chemotherapy in this disease. Previous studies have revealed that HOXA transcript at the distal tip (HOTTIP) is involved in the pathology of GC and is associated with poor overall survival. However, the functional role of HOTTIP in GC chemoresistance remains unclear. In this study, quantitative real-time PCR was used to analyze HOTTIP expression in GC cell lines and in tissues of GC patients who received cisplatin-based chemotherapy. The mechanism of HOTTIP-mediated chemoresistance was assessed using cell viability, apoptosis, and autophagy assays. The relationships among HOTTIP, miR-216a-5p, and Bcl-2 were determined using luciferase reporter and western blot assays. HOTTIP was markedly upregulated in the tissues of GC patients who were treated with gastrectomy and cisplatin chemotherapy, especially in those with recurrent tumors. Further, HOTTIP was increased in the cisplatin-resistant cell line, SGC7901/DDP, compared to the parental cells, SGC7901. Functional assays demonstrated that HOTTIP expression promoted cisplatin resistance and inhibited apoptosis and autophagy in GC cells. Mechanistic investigations revealed that HOTTIP may regulate the functions of GC cells by sponging miR-216a-5p. MiR-216a-5p overexpression decreased Bcl-2 expression, enhanced Beclin1 expression, and active autophagy. Taken together, our study demonstrated that HOTTIP is closely associated with recurrence in GC patients. HOTTIP expression confers cisplatin resistance by regulating the miR-216a-5p/BCL-2/Beclin1/autophagy pathway, which provides a novel strategy to overcome resistance to chemotherapy in GC.

Ectopic HOTTIP expression induces noncanonical transactivation pathways to promote growth and invasiveness in pancreatic ductal adenocarcinoma.

HOXA transcript at the distal tip (HOTTIP), a long noncoding RNA, is upregulated in pancreatic ductal adenocarcinoma (PDAC), but the HOTTIP-mediated oncogenic pathway is not fully understood. We identified canonical HOTTIP-HOXA13 targets, CYP26B1, CLIC5, CHI3L1 and UCP2-responsible for cell growth and cell invasion. Genome-wide analysis revealed that 38% of HOTTIP-regulated genes contain H3K4me3 and HOTTIP enrichment at their promoters, without HOXA13 binding. HOTTIP complexes with WDR5-MLL1 to trans-activate oncogenic proteins CYB5R2, SULT1A1, KIF26A, SLC1A4, and TSC22D1 by directly inducing H3K4me3 at their promoters. The WDR5, MLL1, and H3K4me3 levels at their promoters and their expression levels are sensitive to HOTTIP expression. These results indicate the importance of the noncanonical trans-acting HOTTIP-WDR5-MLL1 pathway in the HOTTIP regulatory mechanism by promoting oncogenic protein expression. Furthermore, HOTTIP is regulated by miR-497 in PDAC cells, but HOTTIP is negatively correlated with miR-497 levels in PDAC tissues. In conclusion, HOTTIP is upregulated in PDAC due to the loss of the inhibitory miR-497; HOTTIP promotes PDAC progression through the canonical HOTTIP-HOXA13 axis. A novel noncanonical trans-acting HOTTIP-WDR5-MLL1-H3K4me3 pathway is also delineated.

Long non-coding RNA HOTAIR and HOTTIP as potential biomarkers for hepatitis C virus genotype 4-induced hepatocellular carcinoma

BackgroundLong non-coding RNAs (lncRNAs) homeobox (Hox) transcript antisense intergenic RNA (HOTAIR) and HOXA transcript at the distal tip (HOTTIP) have been suggested to be implicated in liver cancer tumorigenesis and progression; however, little is known about the role of the plasma HOTAIR and HOTTIP in liver cancer diagnosis and prognosis. The current study aimed at measuring the plasma levels of long non-coding RNAs (HOTAIR and HOTTIP) expression in chronic liver disease (CLD) due to HCV genotype 4 infection with/without cirrhosis and HCC patients in an attempt to evaluate the potential benefits of these new circulating as non-invasive diagnostic biomarkers and a novel therapeutic strategy for liver cirrhosis and carcinogenesis of Egyptian patients. Hundred subjects were included in this study, divided into two groups; group I (50 patients) were classified into subgroup Ia (CLD without cirrhosis, n = 25) and subgroup Ib (CLD with cirrhosis, n = 25), group II (CLD patients with HCC, n = 25), and control (healthy volunteer, n = 25). The expression of lncRNAs (HOTAIR and HOTTIP) genes was analyzed by real-time PCR.ResultsLncRNAs (HOTAIR and HOTTIP) showed upregulation in all diseased groups, which was in consistent with the progression of the disease toward the HCC stage. In addition, HOTAIR and HOTTIP showed a diagnostic ability to discriminate between cases of cirrhosis and HCC compared with healthy control (p < 0.001), while HOTAIR and HOTTIP did not show a discrimination significant differences between cirrhotic cases and non-cirrhotic cases. By using receiver operating characteristic curve (ROC) analysis, it was found that LncRNAs (HOTAIR and HOTTIP) could diagnose liver cancer with 64.0% sensitivity and 86.0% specificity and 48.0% sensitivity and 88.0% specificity. Furthermore, both genes can be considered as the predictor and prognostic parameters for cirrhosis (OR = 1.111, p = 0.05) and (OR = 1.07, p = 0.05) respectively, and HCC (OR = 1.047, p = 0.01) and (OR = 1.05, p = 0.003). The increased HOTAIR and HOTTIP expression were associated with advanced tumor stages and higher grades.ConclusionThese results strongly prompt us that HOTAIR and HOTTIP genes can be used as non-invasive prognostic biomarkers and new therapeutic targets for HCV genotype 4-induced HCC.

Long non-coding (lnc)RNA PAPAS overexpression inhibits tumor growth in papillary thyroid carcinoma by downregulating lncRNA HOTTIP.

The long non-coding (lnc)RNA pre-ribosomal RNA antisense transcripts (PAPAS) can repress ribosomal RNA synthesis, although its role in human disease is currently unknown. The present study aimed to investigate the function of PAPAS in papillary thyroid carcinoma (PTC). PAPAS was downregulated, while the lncRNA HOXA transcript at the distal tip (HOTTIP) was upregulated in patients with PTC. PAPAS and HOTTIP were inversely associated in PTC. PAPAS overexpression led to the downregulation of HOTTIP in PTC cells, while PAPAS expression was not significantly affected by HOTTIP overexpression, suggesting that PAPAS was upstream of HOTTIP. PAPAS expression level decreased, while HOTTIP expression level increased with the increase of clinical staging. PAPAS overexpression led to the inhibition of cell proliferation, while HOTTIP overexpression increased proliferation of PTC cells, and HOTTIP overexpression decreased the effects of PAPAS overexpression. lncRNA PAPAS overexpression may inhibit tumor growth in papillary thyroid carcinoma by downregulating lncRNA HOTTIP.

The Long Non-coding RNA HOTTIP Is Highly Expressed in Colorectal Cancer and Enhances Cell Proliferation and Invasion

Long non-coding RNAs (lncRNAs) are associated with a spectrum of biological processes such as gene regulation on transcriptional and post-transcriptional levels. The HOXA transcript at the distal tip (HOTTIP) lncRNA plays an important role in carcinogenesis; however, the underlying role of HOTTIP in colorectal carcinoma (CRC) remains unknown. The aim of the present study was to evaluate the expression and function of HOTTIP in CRC. In the present study, we analyzed HOTTIP expression levels of CRC patients in tumor and adjacent normal tissue by real-time quantitative PCR. Knockdown of HOTTIP by RNA interference was performed to explore its roles in cell proliferation, migration, and invasion. Our results found that HOTTIP was upregulated in human primary CRC tissues. Knockdown of HOTTIP inhibited CRC cell proliferation, migration, and invasion. Above all, knockdown of HOTTIP could represent a rational therapeutic strategy for CRC.

Long noncoding RNA HOTTIP overexpression: A potential prognostic biomarker in prostate cancer

HOXA transcript at the distal tip (HOTTIP) is a long noncoding RNA (lncRNA), which is >200 nucleotides in length. HOTTIP expression has been demonstrated to play a crucial oncogenic role in cancer pathogenesis, and is said to be associated with poor human cancer prognosis. In prostate cancer, HOTTIP has been identified as an oncogene, but its clinicopathologic significance remains unclear. Array-based qRT-PCR was used to investigate lncRNA levels in 10 pairs of prostate cancer tissues and non-neoplastic parenchyma. Tissue microarray (TMA) was constructed using a total of 70 surgically resected prostatic adenocarcinoma tissues obtained from the Korea University Anam Hospital from 2009 to 2013. HOTTIP expression was determined by RNA in situ hybridization(ISH) and was correlated with clinicopathologic features. Increased HOTTIP expression was observed in all available prostate cancer tissue specimens compared with that in paired normal tissue. High HOTTIP expression was positively associated with bad clinicopathologic features, including higher pathologic T stage (p < 0.001), presence of extraprostatic extension (p < 0.001), seminal vesicle invasion (p < 0.001), perineural invasion (p < 0.001), and the tumor involvement of resection margin (p = 0.044). In particular, significantly increased HOTTIP expression was observed in specimens from patients in the high or very high-risk group, according to the 2018 National Comprehensive Cancer Network (NCCN) guidelines (p < 0.001). Also, patients with high HOTTIP expression showed poorer overall survival than those with low expression. In conclusion, we analytically validated the poor prognostic significance of HOTTIP overexpression and its association with bad clinicopathologic features, and present HOTTIP as a potential prognostic biomarker in prostate cancer.

Long Chain Non-Coding RNA HOTTIP Enhances IL-6 Expression to Promotes Immune Evasion of Ovarian Cancer Cells by Promoting the Expression of PD-L1 in Neutrophils

HOXA transcript at the distal tip (HOTTIP), belonging to the family of long non-coding RNA (lncRNA), is an important biomarker for ovarian cancer (OC) prognosis. Nevertheless, the function of HOTTIP in immune evasion of OC cells remains undecided. In the current study, the effect of HOTTIP on the development of OC was assessed and the mechanism was discovered as well. The neutrophils were isolated from the clinical samples, and the correlation between programmed death-ligand 1 (PD-L1) and interleukin-6 (IL-6) in neutrophils was analyzed. The relationships among HOTTIP, c-jun and IL-6 were investigated by RIP, CHIP, and the dual luciferase reporter gene assay. The roles of PD-L1, IL-6 and HOTTIP on the T cell proliferation and infiltration were measured in vitro and in vivo. Moreover, the association between HOTTIP and IL-6 in OC tissue and the connection between HOTTIP and OC prognosis were evaluated. Positive relationships were observed between IL-6 expression in peripheral blood and the PD-L1 expression in neutrophils of OC patients, and between the HOTTIP and IL-6 expression in OC tissues. HOTTIP could induce the release of IL-6 via c-jun. Besides, HOTTIP boosted the PD-L1 expression in neutrophils and inhibited the T cell proliferation, thus potentiating the immune evasion of OC cells. The prognosis of patients with higher expression of HOTTIP was worse. In summary, the HOTTIP/IL-6/PD-L1 axis was demonstrates as a novel regulatory signaling pathway involving in the progression of OC. Funding Statement: This work is supported by National Natural Science Foundation of China (81472179, 81873975, 81808084), the Excellent Academic Leader Training Program of Shanghai Health System (2018BR31), the Fundamental Research Funds for the Central Universities (22120170071) and the Clinical Research And Cultivation Project of Shanghai Tongji Hospital (ITJ(ZD)1803). We would like to acknowledge the reviewers for their helpful comments on this paper. Declaration of Interests: The authors declare: None. Ethics Approval Statement: This study was permitted by the Ethics Committee of Tongji Hospital of Tongji University and The Sixth People’s Hospital of Yancheng City. Written informed consents were provided by all participants. All animal experiments were conducted under the review from the Animal Ethical and Experimental Committee of Tongji Hospital of Tongji University and The Sixth People’s Hospital of Yancheng City.

LncRNA HOTTIP promotes proliferation and cell cycle progression of acute myeloid leukemia cells.

The aim of this study was to elucidate the biological function of long non-coding RNA (lncRNA) HOTTIP (HOXA transcript at the distal tip) in the development of acute myeloid leukemia (AML), and to investigate the potential mechanism. Relative expression levels of HOTTIP, microRNA-608 and DDA1 in AML patients were determined by quantitative Real-time polymerase chain reaction (qRT-PCR). Meanwhile, the expressions of these genes in AML cell lines were detected as well. The regulatory effects of HOTTIP, microRNA-608 and DDA1 on the proliferative ability and cell cycle progression of AML cells were examined by cell counting kit-8 (CCK-8) and flow cytometry, respectively. Dual-luciferase reporter gene assay was performed to confirm the binding condition of microRNA-608 to HOTTIP and DDA1. Finally, the specific role of HOTTIP/microRNA-608/DDA1 axis in the development of AML was verified through a series of rescue experiments. HOTTIP was highly expressed in AML-M5 patients than normal controls. No significant difference in HOTTIP expression was found between patients with other subtypes of AML (M0, M1, M2, M3, M4 and M6) and normal controls. HOTTIP expression was significantly up-regulated in AML cell lines U-937 and THP-1. Up-regulation of HOTTIP remarkably promoted the proliferative potential and cell cycle progression of AML cells. Dual-luciferase reporter gene indicated that HOTTIP could bind to microRNA-608, which was lowly expressed in AML-M5 patients. Overexpression of microRNA-608 significantly inhibited the proliferative ability and cell cycle progression of U-937 and THP-1 cells. More importantly, microRNA-608 could partially reverse the regulatory effect of HOTTIP on AML cells. Meanwhile, DDA1 was verified as the target of microRNA-608. Subsequent experiments elucidated that DDA1 significantly accelerated the proliferation and cell cycle of AML cells. Furthermore, DDA1 could reverse the inhibitory effect of microRNA-608 on proliferative ability and cell cycle progression of AML cells. HOTTIP accelerated the proliferative ability and cell cycle of AML cells via up-regulating DDA1 expression by sponging microRNA-608.

Long non-coding RNA HOTTIP affects renal cell carcinoma progression by regulating autophagy via the PI3K/Akt/Atg13 signaling pathway.

Renal cell carcinoma (RCC) is the most common malignancy of the urinary system, and it is a serious threat to human health. HOXA transcript at the distal tip (HOTTIP), located at the 5' end of the HOXA locus, is a long non-coding RNA that has been newly discovered in recent years. It has been reported to promote the development of several types of tumors. Moreover, accumulating evidence has indicated that autophagy plays an important role in tumor cell survival or death. However, whether HOTTIP affects RCC development by regulating autophagy remains unknown. In this study, we first measured HOTTIP expression in 42 paired RCC and adjacent non-tumor tissues, as well as in 4 RCC cell lines and 1 normal renal tubular epithelial cell line. Then, we selected 2 RCC cell lines to silence HOTTIP expression and 1 RCC cell line to overexpress HOTTIP, and we measured their proliferation, migration and invasion, as well as autophagy, after pretreatment with an autophagy inhibitor or inducer. In addition, we assessed the growth, metastasis and autophagy of tumors in nude mice and explored the mechanism involved. The results showed that HOTTIP expression was significantly upregulated in the RCC tissues and cell lines, and it was closely associated with TNM stage, histological grade, lymph node metastasis and patient prognosis. The in vitro and in vivo assays indicated that HOTTIP silencing inhibited RCC cell proliferation, migration and invasion and induced autophagy, and 3-MA (an autophagy inhibitor) reversed these effects. In contrast, HOTTIP overexpression and rapamycin (an autophagy inducer) yielded the opposite results. Further research revealed that HOTTIP modification could affect RCC cell autophagy via the PI3K/Akt/Atg13 signaling pathway. Our study will help in finding a potential marker for RCC diagnosis and supply a target molecule for RCC treatment.

Knockdown of HOXA transcript at the distal tip suppresses the growth and invasion and induces apoptosis of oral tongue squamous carcinoma cells.

BackgroundOral tongue squamous cell carcinoma (OTSCC) is an aggressive cancer which has high mortality rates. HOXA transcript at the distal tip (HOTTIP) is a lncRNA that can be used as a prognostic marker in multiple carcinomas. The expression of HOTTIP is found to be elevated in OTSCC tissues, and such elevation is correlated with poor prognosis. However, its functional role in regulating the growth and metastasis of OTSCC cells remains elusive and requires further investigation.MethodsHOTTIP-silenced OTSCC cells were established by inhibiting HOTTIP expression via its exclusive shRNA. Whether HOTTIP knockdown affected the aggressive tumor behaviors of OTSCC cells was investigated in vitro and in vivo.ResultsWe found that HOTTIP shRNA restrained the cell proliferation and arrested the cell cycle at G1 phase in TSCCA and TCA8113 cells. The expression levels of cyclins B, D1, and E were downregulated in HOTTIP-silenced cells. HOTTIP silencing suppressed the growth of xenograft tumors. Moreover, the silencing of HOTTIP triggered apoptosis in TSCCA and TCA8113 cells and altered the expression of a group of apoptosis-related molecules: downregulated Bcl-2, upregulated Bax, and enhanced the cleavage of caspase 3 and PARP. Knockdown of HOTTIP also suppressed the migration, invasion, and epithelial–mesenchymal transition (EMT) of both TSCCA and TCA8113 cell lines.ConclusionOur findings suggest that HOTTIP is required by the OTSCC cells to maintain their growth and metastasis in vitro. It may serve as a promising potential candidate for OTSCC therapy.

Long non-coding RNA HOTTIP promotes prostate cancer cells proliferation and migration by sponging miR-216a-5p.

Long non-coding RNAs (lncRNAs) are a class of ncRNAs with >200 nts in length that regulate gene expression. The HOXA transcript at the distal tip (HOTTIP) lncRNA plays an important role in carcinogenesis, however, the underlying role of HOTTIP in prostate cancer (PCa) remains unknown. The aim of the present study was to evaluate the expression and function of HOTTIP in PCa. In the present study, we analyzed HOTTIP expression levels of 86 PCa patients in tumor and adjacent normal tissue by real-time quantitative PCR (qPCR). Knockdown or overexpression of HOTTIP was performed to explore its roles in cell proliferation, migration, invasion, and cell cycle. Furthermore, bioinformatics online programs predicted and luciferase reporter assay were used to validate the association of HOTTIP and miR-216a-5p in PCa cells. Our results found that HOTTIP was up-regulated in human primary PCa tissues with lymph node metastasis. Knockdown of HOTTIP inhibited PCa cell proliferation, migration, and invasion. Overexpression of HOTTIP promoted cell proliferation, migration, and invasion of PCa cells. Bioinformatics online programs predicted that HOTTIP sponge miR-216a-5p at 3′-UTR with complementary binding sites, which was validated using luciferase reporter assay. HOTTIP could negatively regulate the expression of miR-216a-5p in PCa cells. Above all, the knockdown of HOTTIP could represent a rational therapeutic strategy for PCa.

LncRNA HOTTIP mediated DKK1 downregulation confers metastasis and invasion in colorectal cancer cells.

Recent studies highlight long non-coding RNAs (lncRNAs) as key regulators of cancer biology that contribute to carcinogenesis. The lncRNA HOXA transcript at the distal tip (HOTTIP) is involved in the development of several cancers. Previous studies demonstrated that HOTTIP could promote colorectal cancer (CRC) cell proliferation via silencing of p21 expression. However, the potential role of HOTTIP in CRC metastasis has not yet been discussed. Here, we found that HOTTIP level was significantly higher in CRC than in corresponding adjacent normal tissues, and patients with a larger tumor size, advanced pathological stage, or distant metastasis had higher HOTTIP expression. Moreover, silencing HOTTIP expression by siRNA or shRNA could inhibit CRC cell migration and invasion in vitro and in vivo, whereas HOTTIP overexpression promoted cell metastasis, as documented in the SW480 cell lines. Mechanistic analyses indicated that HOTTIP regulates CRC cell metastasis partly through the downregulation of tumor suppressor DKK1 expression. Collectively, our results suggest that tumor expression of lncRNA HOTTIP plays an important role in CRC metastasis. HOTTIP may serve as a candidate biomarker in this disease.

Long non-coding RNA HOTTIP promotes renal cell carcinoma progression through the regulation of the miR-615/IGF-2 pathway.

Emerging evidence has indicated that long non‑coding RNA (lncRNA) HOXA transcript at the distal tip (HOTTIP) regulates cell growth, differentiation, apoptosis and cancer progression. However, the expression and function of HOTTIP in the progression of renal cell carcinoma(RCC) remain largely unknown. In this study, we investigated the role of the lncRNA HOTTIP in RCC. The expression levels of HOTTIP in RCC tissues and cell lines were determined by RT‑qPCR. The association between HOTTIP expression and clinicopathological characteristics and prognosis was analyzed in patients with RCC from the TCGA database. Loss‑of‑ function assays were designed and conducted to verify the oncogenic function of HOTTIP in RCC progression. Luciferase assay was performed to explore the mechanisms of the miRNA‑lncRNA sponge. The results revealed that HOTTIP expression was upregulated in RCC. An increased HOTTIP expression in RCC was associated with a larger tumor size and a higher clinical stage, lymph node metastasis and vascular invasion. Additionally, patients RCC with a high HOTTIP expression had a significantly shorter overall survival(OS) and disease‑free survival(DFS). HOTTIP knockdown significantly inhibited cell proliferation, migration and invasion, and increased the apoptosis of RCC cells invitro. Mechanistic analyses revealed that HOTTIP functioned as a competing endogenous RNA (ceRNA) for hsa‑miR‑615‑3p, and led to the derepression of its endogenous target, insulin‑like growth factor-2(IGF‑2), which is a protein hormone that exerts a stimulatory effect on tumor cell growth. miR‑615 inhibition reversed the suppressive effects of HOTTIP knockdown on RCC cell progression. HOTTIP regulated IGF‑2 expression in a miR‑615‑dependent manner in RCC cells. In addition, IGF‑2 expression was significantly upregulated in the RCC specimens and a positive association between the expression of HOTTIP and IGF‑2 in RCC tissues was detected. The effect of HOTTIP was abolished by the siRNA‑mediated silencing of IGF-2 in RCC cells. On the whole, this study demonstrates, for the first time, at least to the best of our knowledge, that the HOTTIP/miR‑615/IGF‑2 axis plays an important role in RCC progression and potentially contributes to the improvement of RCC diagnosis and therapy.

Long noncoding RNA HOTTIP alleviates oxygen-glucose deprivation-induced neuronal injury via modulating miR-143/hexokinase 2 pathway.

HOXA transcript at the distal tip (HOTTIP), which is a long noncoding RNA, plays an important role in multiple cancers and in coronary artery disease. Elevated microRNA-143 (miR-143) expression causes impaired glucose uptake that is responsible for the ischemic cerebral injury. However, the role and mechanism of HOTTIP in ischemic stroke are still unknown. The expression of HOTTIP and miR-143 was first detected in mouse models of transient middle cerebral artery occlusion and in primary neurons exposed to oxygen-glucose deprivation (OGD). We used gain-of function and loss-of function approaches in vitro to investigate the effect and mechanism of HOTTIP on ischemic stroke by evaluating cell viability, apoptosis, and glycolytic metabolism of neurons exposed to OGD. The HOTTIP expression was decreased, whereas miR-143 increased in experimental ischemic stroke models. Overexpression of HOTTIP by the pcDNA3.1-HOTTIP plasmid significantly increased cell viability, glucose uptake, and the expression of hexokinase 2 (HK-2) and pyruvate kinase M2 that were reduced by OGD insult. The HOTTIP overexpression also diminished OGD induced the apoptosis and the caspase-3 activity of neurons. The miR-143 mimic reversed these effects, and anti-miR-143 enhanced them. In addition, we found that HOTTIP could function as a competing endogenous RNA for miR-143 to modulate HK-2 expression. In conclusion, the HOTTIP expression was reduced in ischemic stroke. The HOTTIP overexpression attenuated OGD-induced neuronal injury and imbalanced glycolytic metabolism by sponging miR-143, resulting in the de-repression of its endogenous target HK-2. Taken together, these findings improve understanding of the pathogenesis of ischemic stroke.

Interrelation between expression of HOXA transcript at the distal tip and metabotropic glutamate receptor 1 and their influence on prognosis in pancreatic cancer patients

Objective To investigate the clinical significance and interrelation of long-chain non-coding RNA (lcnRNA) HOXA transcript at the distal tip (HOTTIP) and metabotropic glutamate receptor 1 (mGluR1) in pancreatic cancer patients. Methods Pancreatic cancer samples, which were treated in our hospital were collected. The expression levels of HOTTIP and mGlUR1 mRNA were detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in fresh pancreatic cancer tissue, and those of HOTTIP and mGluR1 protein by Western blotting and immunohistochemistry. Moreover, the relationship between the expression of HOTTIP, mGlUR1 and clinicopathological features was analyzed. Results The levels of HOTTIP and mGlUR1 mRNA and protein were significantly up-regulated in pancreatic cancer tissues as compared with normal pancreatic tissue (P=0.000). The expression of HOTTIP protein was positive in 32 samples (68.09%) and mGlUR1 protein was positive in 30 samples (63.83%). The positive rate of HOTTIP and mGlUR1 in adjacent tissues was 31.91% and 36.17%, respectively, and the difference was also statistically significant (P=0.000). The expression of HOTTIP and mGluR1 was correlated with lymph node metastasis, differentiation degree and TNM stage (P=0.000, 0.004, 0.000). The survival time of HOTTIP and mGlUR1 positive patients was significantly shorter than that of negative patients (P=0.029, 0.047). Cox regression multivariate analysis showed that lymph node metastasis, differentiation degree, TNM stage, HOTTIP and mGlUR1 expression were independent prognostic factors for pancreatic cancer (P=0.022, 0.048, 0.026, 0.000, 0.002). In addition, HOTTIP and mGlUR1 expression showed a significant positive correlation in cervical cancer patients (r=0.689, P=0.002). Conclusion The positive expression of HOTTIP and mGlUR1 is associated with the occurrence, progression and prognosis of pancreatic cancer. Key words: Pancreatic cancer; HOXA transcript at the distal tip; Metabotropic glutamate receptor 1; Pathological features; Prognosis