Non-coding RNA HOTTIP Research Articles

LncRNA HOTTIP promotes LPS-induced lung epithelial cell injury by recruiting DNMT1 to epigenetically regulate SP-C.

The objective of this study was to elucidate the involvement of the long noncoding RNA (lncRNA) HOTTIP in acute lung injury and understand the underlying mechanisms. Relevant expression of mRNAs and proteins were assessed by qRT-PCR and western blot assays. Cell viability was determined by employing the CCK-8 assay, and apoptosis was quantified through TUNEL staining. The concentration of inflammatory factors was measured by ELISA. The degree of DNA methylation was quantified through MSP assay. The interaction between HOTTIP and DNA methyltransferase 1 (DNMT1) was examined by RIP assay. LPS upregulated HOTTIP, whereas downregulated SP-C level in AEC II cells. HOTTIP knockdown inhibited LPS-induced apoptosis and the secretion of inflammatory cytokines (TNF-α, IL-1β and IL-6) in AEC II cells. Mechanistically, HOTTIP recruited DNMT1 to the SP-C promoter, thereby facilitating DNA methylation of SP-C and suppressing its expression. Additionally, inhibitory of SP-C reversed the effects of HOTTIP or DNMT1 knockdown on apoptosis and inflammation in AEC II cells induced by LPS. HOTTIP recruited DNMT1 to epigenetically inhibit SP-C expression, leading to the promotion of lung epithelial cell injury caused by LPS, suggesting that targeting HOTTIP may be an effective strategy for the therapy of lung epithelial cell injury.

Long Non-Coding RNA HOTTIP is Elevated in Patients with Sepsis and Promotes Cardiac Dysfunction

ABSTRACT Background Cardiac dysfunction is the most common clinical complication of sepsis. Herein, the study explored the clinical importance of long non-coding RNA (lncRNA) HOXA terminal transcript antisense RNA (HOTTIP) in the onset of sepsis and the development of cardiac dysfunction. Methods 120 patients with sepsis were recruited and divided into cardiac dysfunction group and non-cardiac dysfunction group. Serum HOTTIP levels were measured via RT-qPCR. AC16 cells were treated with lipopolysaccharide (LPS) for cell experiments and detected for cell viability and apoptosis. Results High serum HOTTIP levels were tested in sepsis patients, which was associated with procalcitonin (PCT) level. Serum HOTTIP can identify sepsis cases from healthy people with the AUC of 0.927. 72 cases developed into cardiac dysfunction, accompanied by elevated levels of HOTTIP. ROC curve displayed the predictive ability of serum HOTTIP in the development of cardiac dysfunction in patients with sepsis. After adjusting for other clinical parameters, HOTTIP can independently affect the development of cardiac dysfunction. In vitro, HOTTIP knockdown promoted the recovery of cell viability and reversed LPS-induced cell apoptosis and excessive interleukin-6 (IL-6) release. Conclusion LncRNA HOTTIP is closely related to the condition of patients with sepsis and the development of cardiac dysfunction, possibly owing to its function in LPS-induced myocardial apoptosis and inflammation.

Molecular Regulatory Roles of Long Non-coding RNA HOTTIP: An Overview in Gastrointestinal Cancers.

Gastrointestinal (GI) cancers presented an alarmingly high number of new cancer cases worldwide and are highly characterised by poor prognosis. The poor overall survival is mainly due to late detection and emerging challenges in treatment, particularly chemoresistance. Thus, the identification of novel molecular targets in GI cancer is highly regarded as the main focus. Recently, long non-coding RNAs (lncRNAs) have been discovered as potential novel molecular targets for combating cancer, as they are highly associated with carcinogenesis and have a great impact on cancer progression. Amongst lncRNAs, HOTTIP has demonstrated a prominent oncogenic regulation in cancer progression, particularly in GI cancers, including oesophageal cancer, gastric cancer, hepatocellular carcinoma, pancreatic cancer, and colorectal cancer. This review aimed to present a focused update on the regulatory roles of HOTTIP in GI cancer progression and chemoresistance, as well as deciphering the associated molecular mechanisms underlying their impact on cancer phenotypes and chemoresistance and the key molecules involved. It has been reported that it regulates the expression of various genes and proteins in GI cancers that impact cellular functions, including proliferation, adhesion, migration and invasion, apoptosis, chemosensitivity, and tumour differentiation. Furthermore, HOTTIP was also discovered to have a higher diagnostic value as compared to existing diagnostic biomarkers. Overall, HOTTIP has presented itself as a novel therapeutic target and potential diagnostic biomarker in the development of GI cancer treatment.

Solamargine inhibits the growth of hepatocellular carcinoma and enhances the anticancer effect of sorafenib by regulating HOTTIP-TUG1/miR-4726-5p/MUC1 pathway.

Hepatocellular carcinoma (HCC) is one of the most common primary malignancies. Drug resistance has significantly prevented the clinical application of sorafenib (SF), a first‐line targeted medicine for the treatment of HCC. Solamargine (SM), a natural alkaloid, has shown potential antitumor activity, but studies about antitumor effect of SM are obviously insufficient in HCC. In the present study, we found that SM significantly inhibited the growth of HCC and enhanced the anticancer effect of SF. In brief, SM significantly inhibited the growth of HepG2 and Huh‐7 cells. The combination of SM and SF showed a synergistic antitumor effect. Mechanistically, SM downregulated the expression of long noncoding RNA HOTTIP and TUG1, followed by increasing the expression of miR‐4726‐5p. Moreover, miR‐4726‐5p directly bound to the 3′‐UTR region of MUC1 and decreased the expression of MUC1 protein. Overexpression of MUC1 partially reversed the inhibitory effect of SM on HepG2 and Huh‐7 cells viability, which suggested that MUC1 may be the key target in SM‐induced growth inhibition of HCC. More importantly, the combination of SM and SF synergistically restrained the expression of MUC1 protein. Taken together, our study revealed that SM inhibited the growth of HCC and enhanced the anticancer effect of SF through HOTTIP‐TUG1/miR‐4726‐5p/MUC1 signaling pathway. These findings will provide potential therapeutic targets and strategies for the treatment of HCC.

LncRNA HOTTIP inhibits cell pyroptosis by targeting miR-148a-3p/AKT2 axis in ovarian cancer.

Long noncoding RNA HOTTIP is a crucial regulator in multiple types of cancer, including ovarian cancer (OC). However, the biological roles and underlying mechanisms of HOTTIP in OC have rarely been studied. Hence, this study aimed to investigate the functional correlation between HOTTIP and pyroptosis in OC progression. The expression of HOTTIP in OC tissues and cell lines was characterized by quantitative real-time PCR. Cell proliferation was evaluated using Cell Counting Kit-8 and clone formation assays. Western blotwas performed to quantify protein levels. A dual-luciferase reporter assay was used to analyze the molecular interaction among HOTTIP, miR-148a-3p, and AKT2. The expression of HOTTIP was significantly upregulated in OC tissue samples and cell lines. The silencing of HOTTIP led to the inhibition of cell proliferation and NLRP1 inflammasome-mediated pyroptosis. In addition, HOTTIP increased AKT2 expression by negatively regulating miR-148a-3p and then inhibited ASK1/JNK signaling. Further rescue experiments revealed that downregulation of miR-148a-3p and overexpression of AKT2 obviously diminished the effects of HOTTIP downregulation in OC cells. Thus, our study elucidated a novel pyroptosis-related mechanism by which HOTTIP participated in OC progression, which might provide a theoretical reference for clinical treatment.

Exosomal Long Non-coding RNA HOTTIP Increases Resistance of Colorectal Cancer Cells to Mitomycin via Impairing MiR-214-Mediated Degradation of KPNA3.

It has been reported that long non-coding RNA HOXA distal transcript antisense RNA (lncRNA HOTTIP) functions as a tumor promoter in colorectal cancer (CRC). Hence, we paid attention to exploring whether exosomes could carry lncRNA HOTTIP to affect the mitomycin resistance in CRC and to identify the underlying mechanisms. High expression of HOTTIP was detected in mitomycin-resistant CRC cells. Inhibition of HOTTIP reduced the mitomycin resistance. In the co-culture system of mitomycin-resistant cells or their derived exosomes with CRC cells, the HOTTIP was found to be transferred into the parental cells via extracellular vesicles (EVs) secreted from mitomycin-resistant cells and to contribute to the mitomycin resistance. Based on the bioinformatics databases, possible interaction network of HOTTIP, microRNA-214 (miR-214) and Karyopherin subunit alpha 3 (KPNA3) in CRC was predicted, which was further analyzed by dual-luciferase reporter, RNA binding protein immunoprecipitation and RNA pull-down assays. As HOTTIP down-regulated miR-214 to elevate the KPNA3 expression, HOTTIP enhanced the mitomycin resistance through impairing miR-214-dependent inhibition of KPNA3. Finally, HOTTIP was suggested as an independent factor predicting mitomycin response in patients with CRC. Those data together confirmed the promotive effects of EV-carried HOTTIP on the mitomycin resistance, while targeting HOTTIP might be a promising strategy overcoming drug resistance in CRC.

HOTTIP polymorphism may affect gastric cancer susceptibility by altering HOTTIP expression.

Background: Non-coding RNA polymorphisms can affect disease risk and prognosis by influencing gene expression. Here, we first investigated the association between single nucleotide polymorphisms (SNPs) of long non-coding RNA (lncRNA) HOTTIP and gastric cancer risk/prognosis. Methods: A total of five HOTTIP SNPs among 627 gastric cancer cases and 935 controls were tested by Kompetitive Allele Specific PCR (KASP) assay. The functional SNPs underwent eQTL analysis and the expression of HOTTIP was assessed by quantitative RT-PCR. Results: The rs2067087 and rs3807598 SNPs of HOTTIP increased susceptibility to gastric cancer (rs2067087: dominant model, P=0.008, odds ratio (OR) = 1.35; rs3807598: recessive model, P=0.037, OR = 1.29). Both HOTTIP rs2067087 and rs3807598 could affect the expression of mature lncRNA (P=0.003 and P=0.032, respectively). Conclusion: The rs2067087 and rs3807598 SNPs of HOTTIP are associated with gastric cancer risk, possibly by affecting the expression of mature HOTTIP.

MiR-744–5p mediates lncRNA HOTTIP to regulate the proliferation and apoptosis of papillary thyroid carcinoma cells

Papillary thyroid carcinoma (PTC) is the most common malignancy in thyroid. miR-744–5p plays an efficient role in various cancers, but its role in PTC remains unknown. In this work, we aimed to explore the function of miR-744–5p and the mechanism by which miR-744–5p acted in PTC. We observed that miR-744–5p expression was significantly declined in PTC tissues and cell lines. The high level of miR-744–5p is significantly associated with a better clinical picture of PTC patients. Overexpression of miR-744–5p inhibited the proliferation, arrested the cell cycle, and promoted the apoptosis in PTC cells. Oppositely, down-regulation of miR-744–5p reversed the above tendencies. We also found that miR-744–5p down-regulated its downstream genes c-myc and attenuated cell proliferation induced by c-myc. Long non-coding RNA (lncRNA) HOTTIP was found to be up-regulated and to act as an oncogene in PTC. In this study, miR-744–5p bound to HOTTIP and was negatively regulated by HOTTIP. In conclusion, miR-744-5p acts as a tumor suppressor to inhibit proliferation and promotes the apoptosis of PTC cells via targeting c-myc. Moreover, miR-744-5p expression interferes with lncRNA HOTTIP ability to promote proliferation and downregulate apoptosis in papillary thyroid carcinoma.

Salinomycin reduces epithelial-mesenchymal transition-mediated multidrug resistance by modifying long noncoding RNA HOTTIP expression in gastric cancer cells.

Chemotherapy is the main treatment for advanced gastric cancer. However, the emergence of multidrug resistance (MDR) has become a major obstacle in chemotherapy in many tumors, including gastric cancer. Epithelial-mesenchymal transition (EMT), which is considered an important process in cancer development, also contributes toward tumor MDR. Salinomycin, an EMT blocker, shows broad-spectrum antitumor and chemosensitization properties. Here, we hypothesized that salinomycin could reverse the MDR of SGC7901/cisplatin (CDDP) gastric cancer cell by inhibiting EMT and further explored its possible underlying mechanisms. Our results indicated higher 50% inhibiting concentration (IC50) and stronger migration capacity in SGC7901/CDDP than in SGC7901 cells, whereas salinomycin could reduce the IC50 (50% inhibition of the concentration of chemodrugs after 4 μmol/l salinomycin treatment) and migration capacity in SGC7901/CDDP cells. At the molecular level, we found that the expression of E-cadherin, ZO-1 decreased, whereas the expression of N-cadherin, Vimentin, ZEB-1, and Twist increased in SGC7901/CDDP cells, and that salinomycin potently blocked the EMT by enhancing the expression of E-cadherin, ZO-1 and reducing the expression of N-cadherin, Vimentin, ZEB-1, and Twist in the above MDR cells. In addition, we also found that long noncoding RNA HOTTIP, an oncogenic regulator, was upregulated in SGC7901/CDDP cells, whereas its downregulation could markedly attenuate the EMT, thereby reversing the MDR. Furthermore, our data showed that the salinomycin-elicited MDR-reversion effect was associated closely with suppression of EMT through inhibition of the expression of long noncoding RNA HOTTIP. Collectively, our findings suggest a new underlying mechanism and applicable therapeutic regimen for MDR gastric cancer.

Long Non-coding RNA HOTTIP Promotes CCL3 Expression and Induces Cartilage Degradation by Sponging miR-455-3p.

Long non-coding RNAs (lncRNAs) play pivotal roles in diseases such as osteoarthritis (OA). However, knowledge of the biological roles of lncRNAs is limited in OA. We aimed to explore the biological function and molecular mechanism of HOTTIP in chondrogenesis and cartilage degradation. We used the human mesenchymal stem cell (hMSC) model of chondrogenesis, in parallel with, tissue biopsies from normal and OA cartilage to detect HOTTIP, CCL3, and miR-455-3p expression in vitro. Biological interactions between HOTTIP and miR-455-3p were determined by RNA silencing and overexpression in vitro. We evaluated the effect of HOTTIP on chondrogenesis and degeneration, and its regulation of miR-455-3p via competing endogenous RNA (ceRNA). Our in vitro ceRNA findings were further confirmed within animal models in vivo. Mechanisms of ceRNAs were determined by bioinformatic analysis, a luciferase reporter system, RNA pull-down, and RNA immunoprecipitation (RIP) assays. We found reduced miR-455-3p expression and significantly upregulated lncRNA HOTTIP and CCL3 expression in OA cartilage tissues and chondrocytes. The expression of HOTTIP and CCL3 was increased in chondrocytes treated with interleukin-1β (IL-1β) in vitro. Knockdown of HOTTIP promoted cartilage-specific gene expression and suppressed CCL3. Conversely, HOTTIP overexpression reduced cartilage-specific genes and increased CCL3. Notably, HOTTIP negatively regulated miR-455-3p and increased CCL3 levels in human primary chondrocytes. Mechanistic investigations indicated that HOTTIP functioned as ceRNA for miR-455-3p enhanced CCL3 expression. Taken together, the ceRNA regulatory network of HOTTIP/miR-455-3p/CCL3 plays a critical role in OA pathogenesis and suggests HOTTIP is a potential target in OA therapy.

Long noncoding RNA HOTTIP is associated with male infertility and promotes testicular embryonal carcinoma cell proliferation.

BackgroundIt has been proposed that lncRNAs, widely transcribed from genomes, play pivotal regulatory roles in a variety of biological processes, but their function in regulating spermatogenesis in human males is rarely reported.MethodsQRT‐PCR was adopted to detect HOTTIP expression level in testicular tissues from hypospermatogenesis (Hypo) patients or controls. The proliferation levels of NT2 and 293T were measured via CCK‐8 and EdU detection. Meanwhile, luciferase reporter gene assay and bioinformatics analysis were carried out to identify a target of HOTTIP. Additionally, the underlying mechanism of HOTTIP’s function was investigated using western blotting and RIP analysis.ResultsThe research results manifested that the expression of HOTTIP in testicular tissues from Hypo patients was prominently reduced in comparison with that in control testicular tissues. Interestingly, it was noted that HOTTIP exhibited a high expression in testicular embryonal carcinoma cell line NT2 compared with that in normal control cell line 293T. It was denoted in cell function evaluation that cell proliferation was impeded by downregulated HOTTIP but evidently stimulated by overexpressed HOTTIP. Moreover, HOTTIP was capable of positively modulating HOXA13 expression via the competitive binding to miR‐128‐3p.ConclusionTherefore, HOTTIP acting as ceRNAs to promote testicular embryonal carcinoma cell proliferation.

Long noncoding RNA HOTTIP is a significant indicator of ovarian cancer prognosis and enhances cell proliferation and invasion.

Long noncoding RNAs (LncRNAs) are involved in the occurrence and progression of human tumors including ovarian cancer (OC). Long noncoding RNA HOTTIP has been found to be involved in several human tumors development. However, the role of HOTTIP in OC remains large unknown. In the present study, our results observed that lncRNA HOTTIP expression levels were notably higher in ovarian cancer tissue samples compared to adjacent normal tissue samples. Increased lncRNA HOTTIP expression levels were significantly associated with advanced FIGO stage and lymph node metastasis of ovarian cancer patients. Survival plots analysis results showed high lncRNA HOTTIP expression levels in ovarian cancer patients showed a poor prognosis compared to patients with low lncRNA HOTTIP expression levels. Function assays showed that lncRNA HOTTIP knockdown in ovarian cancer cells decreased cell proliferation and cell invasion capacities. Furthermore, we demonstrated that inhibition of lncRNA HOTTIP suppressed Wnt/β-catenin signaling by downregulating β-catenin expression. Thus, these results suggest that aberrant HOTTIP expression level could serve as a promising biomarker for monitoring ovarian cancer and potential target of ovarian cancer treatment.

Clinical significance of long non-coding RNA HOTTIP in early-stage non-small-cell lung cancer

BackgroundHOTTIP, a long non-coding RNA located in the HOXA cluster, plays a role in the patterning of tissues with mesodermal components, including the lung. Overexpression of HOXA genes, including HOTTIP, has been associated with a more aggressive phenotype in several cancers. However, the prognostic impact of HOTTIP has not yet been explored in non-small-cell lung cancer (NSCLC). We have correlated HOTTIP expression with time to relapse (TTR) and overall survival (OS) in early-stage NSCLC patients.MethodsNinety-nine early-stage NSCLC patients who underwent surgical resection in our center from June 2007 to November 2013 were included in the study. Mean age was 66; 77.8% were males; 73.7% had stage I disease; and 55.5% had adenocarcinoma. A validation data set comprised stage I-II patients from The Cancer Genome Atlas (TCGA) Research Network.ResultsHOTTIP was expressed in all tumor samples and was overexpressed in squamous cell carcinoma (p = 0.007) and in smokers (p = 0.018). Patients with high levels of HOTTIP had shorter TTR (78.3 vs 58 months; p = 0.048) and shorter OS (81.2 vs 61 months; p = 0.023) than those with low levels. In the multivariate analysis, HOTTIP emerged as an independent prognostic marker for TTR (OR: 2.05, 95%CI: 1–4.2; p = 0.05), and for OS (OR: 2.31, 95%CI: 1.04–5.1; p = 0.04). HOTTIP was validated as a prognostic marker for OS in the TCGA adenocarcinoma cohort (p = 0.025). Moreover, we identified a 1203-mRNA and a 61-miRNA signature that correlated with HOTTIP expression.ConclusionsThe lncRNA HOTTIP can be considered a prognostic biomarker in early-stage NSCLC.

Knockdown of the long noncoding RNA HOTTIP inhibits cell proliferation and enhances cell sensitivity to cisplatin by suppressing the Wnt/β-catenin pathway in prostate cancer.

Prostate cancer (PCa) is a prevalent and deadly cancer worldwide. Considering the malignant progression and therapeutic resistance of PCa, further dissection of the underlying mechanisms and exploration of novel therapeutic targets for PCa are urgently needed. The long noncoding RNA HOTTIP has recently been revealed as an oncogenic regulator in different cancers; however, whether HOTTIP is involved in PCa remains poorly understood. Here, we examined the crucial roles of HOTTIP in the proliferation and chemoresistance of PCa. Quantitative real-time PCR (qRT-PCR) was performed to detect the HOTTIP messenger RNA (mRNA) levels in PCa samples from patients and PCa cells. Then, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), colony formation, and cell cycle and flow cytometry assays were performed to investigate the proliferation and cisplatin-resistance of PCa cells with silenced HOTTIP compared with a negative control. We applied Western blotting, qRT-PCR and a TOP/FOP assay to explore the relevant mechanisms. In this study, we found that the HOTTIP mRNA levels were increased in the PCa patient samples and PCa cell lines compared with the controls. The knockdown of HOTTIP not only inhibited the proliferation of PCa cells but also facilitated cell cycle arrest and chemosensitivity to cisplatin. Furthermore, the qRT-PCR, Western blotting, TOP/FOP assays, MTT assay, and flow cytometry revealed that Wnt/β-catenin signaling was related to the regulation of HOTTIP in cell proliferation, cell cycle arrest, and chemoresistance to cisplatin in PCa. Taken together, our findings suggest that HOTTIP may be a potent therapeutic target for PCa, and HOTTIP inhibitors might be regarded as effective strategies for PCa therapy.

Long Noncoding RNA HOTTIP Promotes Nasopharyngeal Cancer Cell Proliferation, Migration, and Invasion by Inhibiting miR-4301.

BackgroundThe long noncoding RNA (lncRNA) HOTTIP is involved in gastric cancer tumorigenesis, papillary thyroid carcinoma, colorectal cancer, lung adenocarcinoma, and hepatocellular carcinoma, but it is unclear how HOTTIP exerts roles in nasopharyngeal carcinoma (NPC). The present study investigated HOTTIP function during NPC development.Material/MethodsHOTTIP levels in cancer specimens and cell lines were analyzed using qRT-PCR. HOTTIP function in NPC was determined by Cell Counting Kit-8 (CCK8) and Transwell assay.ResultsHOTTIP expression was increased in NPC tissues. Higher levels of HOTTIP are correlated with lower survival in NPC patients. HOTTIP silencing suppressed the proliferation, cell cycle, migration, and invasion of NPC cells. HOTTIP served as a sponge for miR-4301. miR-4301 expression was significantly inhibited by HOTTIP in NPC cells. miR-4301 overexpression dramatically inhibited NPC cell proliferation, migration, and invasion.ConclusionsThis study showed that HOTTIP acts as an oncogene in NPC by sponging miR-4301.

Diagnostic Value of Plasma Long Non-coding RNA HOTTIP as a Non-invasive Biomarker for Colorectal Cancer (A Case- Control Study).

Long non-coding RNAs (lncRNAs), associated with various cancers including colorectal cancer (CRC), could be collected from body fluids easily. Our aims were to determine the expression level of HOTTIP lncRNA in plasma samples of healthy individuals and CRC patients as well as their relationship with clinico-pathological characteristics of patients. First, total RNA was extracted from the plasma samples of 100 subjects including 50 patients and 50 age and sex matched healthy persons. Then, gene expression was measured using real-time PCR technique. The sensitivity and specificity of HOTTIP dysregulation in CRC and healthy individual’s plasma was measured by receiver operating characteristic (ROC) analysis. As compared with healthy controls, HOTTIP lncRNA was over expressed in a statistically significant manner in plasma samples of patients (P=0.001). Significant relationship between HOTTIP expression and positive family history of CRC was observed, too (P=0.04). The ROC curve analysis showed an AUC value of 0.775, a specificity of 82%, a sensitivity of 76%, with a cut off value equal to 2.40 (P =0.001). HOTTIP transcript can be proposed as a new biomarker for early diagnosis due to the increased expression in plasma samples of patients with CRC and the relatively high sensitivity and specificity.

Long noncoding RNA HOTTIP expression predicts tumor recurrence in hepatocellular carcinoma patients following liver transplantation.

The long noncoding RNA HOTTIP has recently been described as a biomarker of poor prognosis in patients with hepatocellular carcinoma (HCC). In the present study, we evaluated the clinical significance of HOTTIP expression in predicting the rate of tumor recurrence in HCC patients after liver transplantation (LT). We examined the expression pattern and single nucleotide polymorphism (SNP) genotype of HOTTIP in HCC samples from 155 patients underwent LT, and its correlation with clinical parameters and patient prognosis was analyzed. HOTTIP was suppressed using siRNA to explore the role HOTTIP plays in tumor progression. The expression level of HOTTIP in cancer tissues was higher than in adjacent noncancerous tissues. Multivariate analyses revealed that HOTTIP expression was an independent prognostic factor for tumor recurrence and lower overall survival times in HCC patients after LT. Patients who beyond the Milan criteria and exhibit decreased HOTTIP expression experienced longer recurrence-free survival and overall survival. HOTTIP rs2071265 is associated with an earlier recurrence in HCC patients. Moreover, the suppression of HOTTIP in liver cancer cell lines reduced cell invasion rates and increased chemosensitivity. In summary, the high expression level of HOTTIP in HCC could serve as a candidate biomarker for predicting poor prognosis in HCC patients underwent liver transplant therapy. Furthermore, HOTTIP might be a potential therapeutic target.

Long Noncoding RNA HOTTIP Is Biomarker for Recurrence after Hepatic Metastasectomy for Colorectal Cancer

Kurbatov, Vadim MD; Heller, Danielle R. MD; Zeng, Zhaoshi MD; Paty, Philip B. MD, FACS; Lu, Jun PhD; Khan, Sajid A. MD Author Information

Downregulation of HOTTIP regulates insulin secretion and cell cycle in islet β cells via inhibiting MEK/ERK pathway.

To investigate the effect of long non-coding RNA (lncRNA) HOTTIP on islet β cells and its underlying mechanism. The expressions of HOTTIP in different organs of db/db mice and C57BL/6J mice were detected by quantitative Real-time polymerase chain reaction (qRT-PCR). Effects of HOTTIP on the proliferation, insulin secretion and apoptosis of islet β cells transfected with lentivirus were detected by cell counting kit-8 (CCK-8) assay, enzyme-linked immunosorbent assay (ELISA) and flow cytometry, respectively. We also assessed the protein expressions of key genes in MEK/ERK pathway by using Western blot. HOTTIP was upregulated in normal islet tissues of C57BL/6J mice but downregulated in islet tissues of diabetic mice. Inhibition of HOTTIP attenuated insulin secretion and reduced expressions of Pdx1 and MafA. Downregulation of HOTTIP also inhibited cell proliferation and reduced expressions of CyclinDl, CyclinD2, CyclinE1 and CyclinE2. Moreover, islet β cells were arrested in G0/G1 phase after HOTTIP knockdown. Our data showed that the biological function of HOTTIP in regulating insulin secretion and cell cycle in islet β cells might be related to the MEK/ERK pathway. Downregulation of HOTTIP inhibits insulin secretion and cell cycle in islet β cells via MEK/ERK pathway.

Long non-coding RNA HOTTIP is upregulated in renal cell carcinoma and regulates cell growth and apoptosis by epigenetically silencing of LATS2.

Renal cell carcinoma (RCC) is one of the most aggressive malignancies with increasing incidence worldwide and is characterized by dismal prognosis owing to a lack of early detection and prognostic biomarkers for this fatal disease. Accumulating studies demonstrated that abnormally expressed long non-coding RNAs (lncRNAs) are involved in tumorigenesis and progression. Specifically, HOTTIP is upregulated and exerts oncogenic properties in some cancers. However, its clinical significance, biological functions and molecular mechanisms in RCC have not been studied. In the current study, RT-qPCR was performed to quantify the relative expression of HOTTIP in RCC tissues and cells. Additionally, we explored its clinical value using Fisher's exact test. Moreover, cell growth and apoptosis altered by HOTTIP was evaluated in vitro and in vivo. Mechanistically, RNA immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP) analysis was used to determine its molecular mechanism in cell growth and apoptosis. As a result, upregulated HOTTIP is closely associated with unfavorable phenotypes in RCC patients. The mechanistic investigations showed that HOTTIP could bind to enhancer of zeste homolog 2 (EZH2) and lysine specific demethylase 1 (LSD1), thereby repressing LATS2 expression. Collectively, our study illustrates how HOTTIP plays an oncogenic role in RCC and may offer a potential therapeutic target for treating this fatal disease.