Expression Of Tumor Suppressor Candidate 7 Research Articles

LncRNA TUSC7 sponges miR-10a-5p and inhibits BDNF/ERK pathway to suppress glioma cell proliferation and migration.

Gliomas as primary cerebral malignancies frequently occurring in adults have relatively high morbidity and mortality. The underlying role of long non-coding ribonucleic acids (lncRNAs) in malignancies has attracted much attention, among which tumor suppressor candidate 7 (TUSC7) is a novel tumor suppressor gene whose regulatory mechanism in human cerebral gliomas remains inconclusive. In this study, bioinformatics analysis indicated that TUSC7 could specifically bind to microRNA (miR)-10a-5p, and according to quantitative polymerase chain reaction (q-PCR), miR-10a-5p was up-regulated in human glioma cells and negatively correlated with TUSC7 expression. Dual-luciferase reporter gene assay showed the ability of TUSC7 to bind to miR-10a-5p, and overexpression of TUSC7 notably inhibited miR-10a-5p expression, restrained human glioma cell proliferation and migration, and regulated cell cycle and cyclin expression via the brain-derived neurotrophic factor/extracellular signal-regulated kinase (BDNF/ERK) pathway. The inhibitory effect of TUSC7 on miR-10a-5p was also verified by designing miR-10a-5p overexpression and knockdown panels for wound healing, Transwell and Western blotting assays. TUSC7 suppresses human glioma cell proliferation and migration by negatively modulating miR-10a-5p and inhibiting the BDNF/ERK pathway, thus acting as a tumor suppressor gene in human gliomas.

Long non-coding RNA TUSC7 suppressed colorectal cancer progression via regulation of miR-23b/PDE7A Axis.

Despite advances in our understanding of the roles of the long noncoding RNA (lncRNA) tumor suppressor candidate 7 (TUSC7) in cancer biology, which has been identified to act as a tumor suppressor by regulating cell proliferation, apoptosis, migration, invasion, cell cycle and tumor growth, its function in colorectal cancer remains unknown. The expression levels of TUSC7 in colorectal cancer tissues and cell lines were determined, and the biological functions of TUSC7 to cancer progression in colorectal cancer were investigated via correlation analysis of clinical samples, cell viability assay, transwell assay and apoptosis analysis. Further, the molecular regulatory mechanisms of TUSC7 were demonstrated by luciferase reporter assay and western blotting. We observed that the expression of TUSC7 was markedly decreased in colorectal cancer cell lines. Moreover, the lower expression of TUSC7 was correlated with advanced clinical grades and poorer survival and may be an independent risk factor for colorectal cancer. Moreover, the expression of TUSC7 inhibited cell proliferation, invasion and epithelial-to-mesenchymal transition (EMT), while it facilitated apoptosis through competitively binding miR-23b. We also found that TUSC7 decreased the expression of phosphodiesterase 7A (PDE7A), a downstream target of miR-23b, through the TUSC7/miR-23b/PDE7A axis. We demonstrated the expression of TUSC7 suppressed colorectal cancer progression through the TUSC7/miR-23b/PDE7A axis, suggesting that TUSC is a potential target for therapeutic intervention in colorectal cancer.

LncRNA TUSC7 inhibits osteosarcoma progression through the miR‑181a/RASSF6 axis.

Osteosarcoma (OS) is one of the most aggressive malignancies, accompanied by an elevated incidence and a decreased rate of healing. Recently, several long non-coding RNAs (lncRNAs) have been reported to be involved in OS progression. Although tumor suppressor candidate 7 (TUSC7) was reported as a novel lncRNA, little is known about its biological functions in OS. The present study was designed to explore whether TUSC7 was involved in the pathological development of OS using various methods, including hematoxylin and eosin staining, Cell Counting Kit-8 assay, colony formation assay and Transwell assay. The present study revealed that TUSC7 expression was downregulated in OS tissues and cell lines compared with in normal tissues and cell lines. Functionally, the current results revealed that overexpression of TUSC7 inhibited OS cell proliferation, migration and invasion, while promoting apoptosis in vitro and in vivo. Next, the subcellular distribution of TUSC7 was examined by nuclear/cytoplasmic RNA fractionation and reverse transcription-quantitative PCR. Mechanistic studies revealed that TUSC7 exerted its role by sponging microRNA (miR)-181a in OS cell lines. Ras association domain family member 6 (RASSF6) was confirmed as a target gene of miR-181a, and the expression levels of RASSF6 were negatively regulated by miR-181a. Additionally, the results of rescue experiments suggested that overexpression of miR-181a neutralized the inhibitory effects of TUSC7 overexpression on OS cells. Overall, the present study demonstrated that the tumor suppressor role of TUSC7 in OS progression was mediated through the miR-181a/RASSF6 axis, which may represent a new therapeutic target for OS.

Overexpression of lncRNA TUSC7 reduces cell migration and invasion in colorectal cancer.

Colorectal cancer (CRC) is a highly heterogeneous disease worldwide. Long non‑coding RNA (lncRNA) tumor suppressor candidate 7 (TUSC7) plays a crucial role in the development of several cancers. However, the role of TUSC7 in the tumorigenesis of CRC has not been explored. The TUSC7‑overexpressing CRC cell lines SW480 and CaCo‑2 were generated to investigate the effects of TUSC7 on the growth, migration, invasion and epithelial‑mesenchymal transition (EMT) of CRC cells. CCK‑8, wound‑healing and Transwell assays were used to evaluate CRC cell proliferation, migration and invasion. The mRNA and protein expression of TUSC7 were detected by quantitative real‑time PCR and immunoblotting, respectively. In the present study, we observed that the expression of TUSC7 was decreased in CRC cells compared to the expression in the normal colon epithelial cell line NCM460. Moreover, overexpression of TUSC7 inhibited CRC cell proliferation, metastasis, invasion and EMT. These findings indicated that TUSC7 is involved in CRC development.

LncRNA TUSC7 suppresses pancreatic carcinoma progression by modulating miR-371a-5p expression.

Pancreatic carcinoma is one of the most common and lethal human malignancies worldwide. Long noncoding RNAs (lncRNAs) are a well-known type of nonprotein-coding transcripts implicated in cancer development and progression. Increasing evidence has indicated that lncRNA tumor suppressor candidate 7 (TUSC7) is a novel cancer suppressor gene in various cancers. Nevertheless, the function of TUSC7 in pancreatic carcinoma is urgent to be clarified. We found that TUSC7 was notably decreased in tissues and cell lines of pancreatic carcinoma. Moreover, the low expression of TUSC7 was correlated with advanced clinical grades and poorer overall survival. Our findings revealed that TUSC7 repressed cell proliferation, migration, invasion, epithelial-mesenchymal transition, and stemness whereas facilitated cell apoptosis of pancreatic carcinoma cells. Further investigations demonstrated that miR-371a-5p directly bound with TUSC7 and negatively regulated by TUSC7. MiR-371a-5p rescued the inhibitory effects of TUSC7 on the development of pancreatic carcinoma. We conclude that lncRNA TUSC7 suppresses pancreatic carcinoma progression by modulating miR-371a-5p expression, indicating an innovative therapeutic strategy for pancreatic carcinoma.

Long non-coding RNA TUSC7 inhibits temozolomide resistance by targeting miR-10a in glioblastoma.

Human glioblastoma multiforme (GBM) is the most malignant intracranial primary cancer and is associated with high mortality and poor prognosis. This study aimed to investigate the regulatory effects and mechanism of tumor suppressor candidate 7 (TUSC7) gene to malignant proliferation and chemotherapy resistance to temozolomide (TMZ) in glioma cells. The expression of TUSC7 was detected by quantitative real-time PCR. CCK-8 assay was used to detect cell proliferation ability and chemosensitivity. Flow cytometry were used to detect cell cycle and cell apoptosis. The expression of MDR1 protein was examined by western blot. RNA pull-down assay was applied to confirm the specific combination between TUSC7 and miR-10a. In the present study, we detected low expression of TUSC7 in GBM cells and tissues resistant to TMZ. Upregulation of TUSC7 suppressed both TMZ resistance and expression of multidrug resistance protein 1 (MDR1) in U87TR cells. TUSC7 acted by directly targeting and silencing expression of miR-10a gene, and miR-10a mediated TUSC7-induced inhibition on TMZ resistance in U87TR cells. These findings suggest a negative correlation between TUSC7 expression and TMZ resistance and provide a mechanism and rationale for targeting TUSC7 in the treatment of GBM.

Prognostic value of decreased long non-coding RNA TUSC7 expression in some solid tumors: a systematic review and meta-analysis.

Accumulating evidences indicated that tumor suppressor candidate 7 (TUSC7) is a putatively tumor suppressor gene in various tumors. We carried out current systematic review and meta-analysis to explore the decreased expression of TUSC7 associate with prognostic and clinicopathological characteristic in cancer patients. A literature collection search in the online electronic databases PubMed, Embase, Web of Science, and CNKI was conducted to obtain eligible studies (up to February 20, 2017). A total of nine studies comprise 757 patients were identified and included in present meta-analysis based on the selection and inclusion criteria. Overall, low expression of TUSC7 was associated with significantly unfavorable overall survival (OS) (HR = 2.90, 95% CI: 2.12–3.98, P < 0.001), disease free survival (DFS) (HR = 2.00, 95% CI: 1.49–2.68, P < 0.001) and disease-specific survival (DSS) (HR = 2.57, 95% CI: 1.23–5.39, P = 0.012) in tumors patients. Moreover, we also found that down-regulation of TUSC7 associated with distant metastasis (OR = 2.85, 95% CI: 1.46–5.55, P = 0.002) and larger tumor size (OR = 0.41, 95% CI: 0.23–0.72, P = 0.002). Our meta-analysis demonstrated that cancers patients detected with low TUSC7 expression were more prone to develop distant metastasis. TUSC7 might act as a potentially and promising common prognostic markers in some solid tumors.

Long non-coding RNA tumor suppressor candidate 7 advances chemotherapy sensitivity of endometrial carcinoma through targeted silencing of miR-23b.

Endometrial carcinoma is the most common malignant tumor of the female genital tract worldwide. TUSC7 (tumor suppressor candidate 7) is an antisense long non-coding RNA and is downregulated and acts as a potential tumor suppressor in several malignant tumors. In this study, the low expression of TUSC7 was confirmed in endometrial carcinoma tissues and was associated with high pathological stages of endometrial carcinoma, which revealed that TUSC7 might be involved in tumorigenesis and progression of endometrial carcinoma. Moreover, the expression of TUSC7 in endometrial carcinoma tissues and cell lines resistant to CDDP and Taxol was lower than that in sensitive endometrial carcinoma tissues and cell lines, which indicated that the TUSC7 expression level was positively correlated with the response of endometrial carcinoma patients to chemotherapy with CDDP and Taxol. TUSC7 upregulation inhibited proliferation, blocked cells at G1 phase, and advanced apoptosis and chemotherapy sensitivity to CDDP and Taxol in HEC1A/CR cell line. Furthermore, miR-23b was upregulated in endometrial carcinoma and negatively correlated with the expression of TUSC7. RNA pull-down assay indicated that TUSC7 could specifically silence the expression of miR-23b in HEC1A/CR cell line; miR-23b was a target gene of TUSC7. MiR-23b upregulation mostly reversed the TUSC7-induced regulatory effects on HEC1A/CR cell line. In summary, long non-coding RNA TUSC7 was underexpressed in endometrial carcinoma, especially in endometrial carcinoma chemotherapy-resistant tissues and cell lines and acted as a potential tumor suppressor gene to inhibit cell growth as well as advance the chemotherapy sensitivity through targeted silencing of miR-23b, which might provide a new therapeutic target to endometrial carcinoma.

The Novel Long Noncoding RNA TUSC7 Inhibits Proliferation by Sponging MiR-211 in Colorectal Cancer

Background/Aims: The novel long noncoding RNA (lncRNA) tumor suppressor candidate 7 (TUSC7) has been reported as a potential tumor suppressor, while the functional role of TUSC7 is still unknown in colorectal cancer (CRC). Here, we characterized TUSC7 expression profile in CRC patients and investigated its biological function and potential molecular mechanism. Methods: RNA isolation, qRT-PCR, cell counter kit-8 assay, cell cycle assay, EdU assay, and western blot were performed. Statistical analyses were performed using SPSS 18.0 software and p value < 0.05 was considered as statistically significant. Results: In a cohort of CRC patients, we found TUSC7 was significantly downregulated in CRC tissues compared with adjacent non-tumor tissues (P < 0.01). Patients with high expression of TUSC7 had better survival than those with low expression of TUSC7 (HR = 0.342, 95% CI: 0.120-0.972, P = 0.044). Cell count kit 8 and EdU assays showed that ectopic expression of TUSC7 in HCT116 and SW480 cells significantly inhibited cell proliferation rate. After silence of TUSC7 with small interfering RNA, cell proliferation rate increased. Flow cytometry analyses revealed cycles were arrested at G1 phase after TUSC7 overexpression. We found there were 2 binding sites of miR-211-3p within the sequence of TUSC7 and TUSC7 expression level was negatively correlated with miR-211-3p. TUSC7 overexpression increased the expression level of CDK6, which is a downstream target of miR-211-3p, in both RNA and protein level. Furthermore, luciferase reporter assay indicated that TUSC7 could sponge miR-211-3p. Conclusion: To summary, we demonstrated that TUSC7 is a potential tumor suppressor in CRC, and TUSC7 could inhibit CRC cell proliferation by completely sponging miR-211-3p.

Long non-coding RNA TUSC7 acts a molecular sponge for miR-10a and suppresses EMT in hepatocellular carcinoma.

Despite advances in the roles of long non-coding RNA (lncRNA) tumor suppressor candidate 7 (TUSC7) in cancer biology, which has been identified as a tumor suppressor by regulating cell proliferation, apoptosis, migration, invasion, cell cycle, and tumor growth, the function of TUSC7 in hepatocellular carcinoma (HCC) remains unknown. In this study, we observed that the expression of TUSC7 was immensely decreased in HCC. Clinically, the lower expression of TUSC7 predicted poorer survival and may be an independent risk factor for HCC patients. Moreover, TUSC7 inhibited cell metastasis, invasion, and epithelial-to-mesenchymal transformation (EMT) through competitively binding miR-10a. Furthermore, we found that TUSC7 could decrease the expression of Eph tyrosine kinase receptor A4 (EphA4), a downstream target of miR-10a as well as an EMT suppressor, through TUSC7-miR-10a-EphA4 axis. Taken together, we demonstrate that TUSC7 suppresses EMT through the TUSC7-miR-10a-EphA4 axis, which may be a potential target for therapeutic intervention in HCC.

Long non-coding RNA tumor suppressor candidate 7 functions as a tumor suppressor and inhibits proliferation in osteosarcoma

Osteosarcoma is the most common malignant tumor of bone. Recent studies have proven long non-coding RNAs (lncRNAs) play important roles in the tumorigenesis and progression of cancer. However, few lncRNAs have been investigated in osteosarcoma. Here, we reported a novel lncRNA, tumor suppressor candidate 7 (TUSC7), was significantly downregulated in osteosarcoma tissues compared with paired non-tumor tissues and low expression of TUSC7 indicated poor survival (HR = 0.313, 95% confidence interval (CI) 0.092-0.867) of osteosarcoma patients. Further analysis revealed that loss copy number of TUSC7 was correlated with low expression of TUSC7, and additionally, loss of TUSC7 copy number also indicated poor prognosis (HR = 3.994, 95% CI 1.147-13.91) of osteosarcoma patients. Two osteosarcoma cell lines, HOS and MG63, were utilized to investigate biological function of TUSC7. Cell counting kit 8 (CCK-8) assay revealed that after silence of TUSC7, cell proliferation ability increased and the colony formation ability also increased. Further results showed that cell cycle was not affected by treatment of si-TUSC7, while the percentage of apoptotic cells decreased. Western blot showed that after silence of TUSC7, the proapoptotic Bcl2 expression was downregulated. Finally, we established xenograft tumor models in nude mice with MG63 cells. Compared with negative control group, silence of TUSC7 significantly promoted tumor growth in vivo. Thus, we demonstrated that TUSC7 could be a potential tumor suppressor in osteosarcoma.