LSINCT5: a novel lncRNA in cancers

BACKGROUND

Long chain non-coding RNAs (lncRNA) are a kind of transcript that is around 200 nucleotides long and can engage in life activities via epigenetic, transcriptional, and post-transcriptional regulation. One of the key members of lncRNAs, long stress-induced noncoding transcripts 5 (LSINCT5), is localized at Chr 5p and has been reported to be abnormally expressed in a range of cancers. We present a comprehensive review of LSINCT5's aberrant expression and regulatory mechanisms in malignant tumors.

METHOD

The included studies were retrieved and summarized through the PubMed database using the keywords "LSINCT5" and "Cancer" in detail.

RESULTS

LSINCT5 behaves as an oncogene and abundantly expresses in malignant tumorigenesis and progression. By sponging microRNAs (miRNA), interacting with proteins, participating in cellular transduction, and being regulated by transcription factors, LSINCT5 can stimulate malignant behavior in a variety of tumor cells, including proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT). Furthermore, dysregulated LSINCT5 is usually associated with a poor prognosis.

CONCLUSION

LSINCT5 has the potential to become a tumor diagnostic and prognostic marker, generating new access to clinical applications.

Long stress-induced non-coding transcript 5: A promising therapeutic target for cancer treatment

Long non-coding RNAs are RNA molecules with a transcript length of more than 200 nucleotides and without protein-coding ability. They regulate gene expression by interacting with protein, RNA and DNA. Their function is closely related to their subcellular localization, with regulation of gene expression at the epigenetic and transcriptional levels occurring in the nucleus, and at the post-transcriptional and translational levels in the cytoplasm. Long stress-induced non-coding transcript 5 (LSINCT5), which is localized in the nucleus, is overexpressed in many types of cancers such as breast cancer, gastric cancer, ovarian cancer, thyroid cancer, and gastrointestinal cancer. Substantial evidence indicates that there is an obvious connection between cancers and LSINCT5, as it inhibits apoptosis and promotes proliferation, invasion and migration of cancer cells, as well as participates in the pathogenesis and progression of cancer by interacting with DNA, protein and RNA. These findings suggest that LSINCT5 could be a novel biomarker and an emerging therapeutic target in human cancers. In the present study, the structure and corresponding biological function of LSINCT5 were summarized in order to clarify its molecular mechanisms in the progression of various malignant tumors.

lncRNA LSINCT5 Regulates miR-20a-5p/XIAP to Inhibit the Growth and Metastasis of Osteosarcoma Cells

Background

More and more evidence has shown that non-coding RNA (ncRNA), including long ncRNA (lncRNA) and micro RNA (miRNA), plays a crucial regulatory role in osteosarcoma (OS). Previously, we revealed a Rho-related coiled coil incorporating protein kinase 1(XIAP). A transfer-related gene is negatively regulated by microRNA-20a-5p (miR-20a-5p) and plays the role of oncogene in OS. It is not clear if any lncRNA is involved in the axial upstream of miR-20a-5p/XIAP.

Methods

Expression of LSINCT5 and miR-20a-5p/XIAP in OS tissues was determined through qRT-PCR (qP). The proliferation and migration/invasion activity of OS cells were tested through CCK-8/and transwell assay, respectively. The changes on expression of XIAP were examined through qRT-PCR and Western blot (WB). Targeted binding between LSINCT5, miR-20a-5p, and XIAP has been verified using dual luciferase reporter gene analysis, RNA Immunoprecipitation (RIP), and RNA pull-down experiments. The effect of LSINCT5 on tumor growth was determined by tumor allograft test.

Results

In this study, elevated LSINCT5 was found in OS tissue samples and OS cell strains, and the increased LSINCT5 was strongly related to the adverse prognosis of clinical patients. Functional assays showed that inhibition of LSINCT5 could up-regulate miR-20a-5p-mediated OS cells proliferation and metastasis. WB analysis and qP analysis showed that LSINCT5 regulated XIAP by mediating miR-20a-5p. Further cell behavior experiments showed that LSINCT5 acted as a miR-20a-5p sponge to inhibit proliferation and metastasis caused by XIAP. Finally, the results of animal models in vivo showed that LSINCT5 could regulate the tumor growth of OS.

Conclusion

LncRNA LSINCT5 acts as an oncogene and promotes XIAP mediated growth and metastasis as competitive endogenous RNA (ceRNA) in OS.

Knockdown of lncRNA LSINCT5 suppresses growth and metastasis of human glioma cells via up-regulating miR-451

Background: Glioma is a main cause of brain-cancer relevant death. The present paper designed to reveal the possible role of LSINCT5 in human glioma GL15 cells. Methods: LSINCT5 and miR-451 expression in glioma tissues was examined using qRT-PCR. The impacts of LSINCT5, miR-451 and Rac1 in GL15 cells were checked by carrying out CCK-8 assay, transwell assay, and flow cytometric analysis. Further, the target gene of LSINCT5 and miR-451 was explored. Accumulation of PI3K/AKT, Wnt/β-catenin and NF-κB pathway proteins was examined using Western blot. Results: LSINCT5 was highly expressed while miR-451 low expressed in glioma tissues when compared to normal controls. Down-regulating LSINCT5 effectively declined GL15 cells viability, migration and invasion, but accelerated apoptosis. Nonetheless, the above-mentioned effects of LSINCT5 down-regulation were weakened when miR-451 was silenced. Rac1 was a target of miR-451. The tumour-suppressive effects of miR-451 on GL15 cells were weakened when Rac1 was overexpressed. Further, LSINCT5-miR-451-Rac1 axis could impact the activation of PI3K/AKT, Wnt/β-catenin and NF-κB pathways. Conclusion: Down-regulation of LSINCT5 represses glioma cells growth and metastasis in vitro likely through targeting miR-451 and thereby inhibiting Rac1-regulated PI3K/AKT, Wnt/β-catenin and NF-κB pathways.

Long noncoding RNA LSINCT5 promotes endometrial carcinoma cell proliferation, cycle, and invasion by promoting the Wnt/β-catenin signaling pathway via HMGA2

Background:

A review of the evidence has indicated the critical role of long noncoding RNA (lncRNA) LSINCT5 in a large number of human cancers. However, the mechanistic involvement of LSINCT5 in endometrial carcinoma (EC) is still unknown. Here the authors aim to characterize the expression status of LSINCT5 and elucidate its mechanistic relevance to EC.

Methods:

Relative expression of LSINCT5 and HMGA2 were quantified by a real-time polymerase chain reaction. SiRNAs were employed to specifically knockdown endogenous LSINCT5 in EC cells. Cell proliferation was measured with Cell Count Kit-8 kit (CCK-8, Dojindo, Kumamoto, Japan) and cell growth was assessed by a colony formation assay. The cell cycle was analyzed with propidium iodide (PI) staining. Apoptotic cells were determined by flow cytometry after Annexin V/PI double-staining. Cell migration was evaluated by a wound-healing assay, and cell invasion was assessed using a transwell migration assay. The protein levels of HMGA2, Wnt3a, p-β-catenin, c-myc, β-actin, and GAPDH were determined by western blot.

Results:

The authors observed positively correlated and aberrantly up-regulated LSINCT5 and HMGA2 in EC. LSINCT5 deficiency significantly inhibited cell proliferation, cell cycle progression, and induced apoptosis. Meanwhile, cell migration and invasion were greatly compromised by the LSINCT5 knockdown. LSINCT5 stabilized HMGA2, which subsequently stimulated activation of Wnt/β-catenin signaling and consequently contributed to the oncogenic properties of LSINCT5 in EC.

Conclusions:

Our data uncovered the oncogenic activities and highlighted the mechanistic contributions of the LSINCT5-HMGA2-Wnt/β-catenin signaling pathway in EC.

LSINCT5 predicts unfavorable prognosis and exerts oncogenic function in osteosarcoma

The dysregulated expression of LSINCT5 (long stress-induced non-coding transcript 5) has been found in various human tumors, and was generally related to cancer progression and unfavorable prognosis. Although the role of LSINCT5 in osteosarcoma was reported not long ago, the sample size of that study was limited. Our study presented more evidence about the clinical significance and biological function of LSINCT5 in osteosarcoma. In our results, we found LSINCT5 expression was increased in osteosarcoma tissue samples and cell lines, and high LSINCT5 expression was associated with advanced Enneking stage, large tumor size, high histological grade and present distant metastasis. Meanwhile, we observed high LSINCT5 expression was correlated with worse overall survival, and high LSINCT5 expression could be an independent poor predictor for overall survival in osteosarcoma cases. Moreover, we found inhibition of LSINCT5 expression suppressed cell proliferation, migration and invasion in vitro, and LSINCT5 overexpression dramatically facilitated cell proliferation, migration and invasion in vitro. In conclusion, our study suggests that LSINCT5 exerts oncogenic function in osteosarcoma cells, and may be a potential predictor for clinical outcome in osteosarcoma patients.

E2F1 induces LSINCT5 transcriptional activity and promotes gastric cancer progression by affecting the epithelial-mesenchymal transition

Background

Long noncoding RNAs (lncRNAs) have been shown to play important regulatory roles in human cancer. We previously verified that the lncRNA long stress-induced noncoding transcript 5 (LSINCT5) is overexpressed in gastric cancer (GC) cells and closely correlated with cell proliferation and patient prognosis. However, whether aberrant LSINCT5 expression has an important effect on GC progression is unclear, and the potential mechanisms remain unknown. In GC, E2F1 expression is also aberrant, but the biological functions of E2F1 are controversial, and the correlation between E2F1 and lncRNAs remains unknown.

Materials and methods

Expression of LSINCT5 was analyzed in metastatic GC tissues compared with nonmetastatic tissues using quantitative real-time PCR (qRT-PCR) assays. Gain and loss of function approaches were used to investigate the biological role of LSINCT5 in GC cell migration and invasion. A computational screen of LSINCT5 promoter was conducted to search for transcription factor-binding sites. LSINCT5 promoter activities were examined by ChIP and luciferase reporter assays. qRT-PCR and western blotting assays were performed to detect the expression of multiple EMT markers in cells in which LSINCT5 was overexpressed or knocked down.

Results

An integrated quantitative analysis revealed that LSINCT5 was significantly over-expressed in metastatic GC tissues. Forced LSINCT5 expression promoted cell migration and invasion, whereas loss of LSINCT5 function decreased cell migration and invasion. Mechanistic investigations showed that LSINCT5 is a direct transcriptional target of E2F1. Moreover, LSINCT5 overexpression was found to play an important role in the epithelial-to-mesenchymal transition by regulating the expression of E-cadherin, N-cadherin, vimentin, and matrix metalloproteinase-2.

Conclusion

These data suggest that E2F1-mediated activation of LSINCT5, a regulator of cell migration and invasion, constitute the mechanistic link between the E2F1-mediated pathway and lncRNA that regulates cell migration and invasion. Thus, LSINCT5 may be a target for new GC therapies.

The long non-coding RNA LSINCT5 promotes malignancy in non-small cell lung cancer by stabilizing HMGA2

Long non-coding RNAs (lncRNAs) can actively participate in tumorigenesis in various cancers. However, the involvement of lncRNA long stress induced non-coding transcripts 5 (LSINCT5) in non-small cell lung cancer (NSCLC) remains largely unknown. Here we showed a novel lncRNA signature in NSCLC through lncRNA profiling. Increased LSINCT5 expression positively correlates with malignant clinicopathological features and poor survival. LSINCT5 can promote migration and viability of various NSCLC cells in vitro and also enhance lung cancer progression in vivo. RNA immunoprecipitation followed by mass spectrometry has identified that LSINCT5 interacts with HMGA2. This physical interaction can increase the stability of HMGA2 by inhibiting proteasome-mediated degradation. Therefore, LSINCT5 may possibly contribute to NSCLC tumorigenesis by stabilizing the oncogenic factor of HMGA2. This novel LSINCT5/HMGA2 axis can modulate lung cancer progression and might be a promising target for pharmacological intervention.

Long non-coding RNA LSINCT5 promotes ovarian cancer cell proliferation, migration and invasion by disrupting the CXCL12/CXCR4 signalling axis

Long stress-induced noncoding transcript 5 (LSINCT5) is a member of the LSINCT family, members of which are expressed during stress-induced cell formation and have also been reported to promote cancer progression. In the present study, the association between LSINCT5 expression and clinical significance was investigated and the biological function of LSINCT5 in epithelial ovarian cancer (EOC) was explored. LSINCT5 expression was examined in EOC tissues by reverse transcription-quantitative polymerase chain reaction and its association with clinicopathological factors was analysed. Cell proliferation, migration and invasion tests were performed to observe the role of LSINCT5 in human ovarian cancer cell lines in vitro. The negative control (NC) and siLSINCT5 SKOV3 cells were treated with chemokine ligand 12 (CXCL12) and their proliferation, migration and invasion activities were examined. LSINCT5 was overexpressed in EOC compared with normal ovarian tissue. LSINCT5 expression was significantly associated with the International Federation of Gynecologists and Obstetricians cancer stage and the presence of lymphatic metastases. Silencing LSINCT5 significantly reduced the expression of chemokine receptor 4 (CXCR4) and inhibited SKOV3 cell proliferation, migration and invasion, however the CXCL12 expression level had no significant change. When NC and siLSINCT5-SKOV3 cells were treated with CXCL12, the proliferation and invasion ability were significantly enhanced. The migration ability of the siLSINCT5-SKOV3 cells was also significantly enhanced. The present study indicated that LSINCT5 serves an important role in ovarian cancer metastasis by regulating the CXCL12/CXCR4 signalling axis, suggesting that this pathway may be a potential target for the treatment of patients with EOC.