Cancer Susceptibility Candidate 2 Overexpression Research Articles

Long Non-Coding RNA CASC2 Functions as A Tumor Suppressor in Colorectal Cancer via Modulating The miR-18a-5p/BTG3 Pathway.

Reportedly, long non-coding RNA (lncRNA) cancer susceptibility candidate 2 (CASC2) is involved in regulating colorectal cancer (CRC) progression. However, the function and detailed downstream mechanism of CASC2 in CRC progression are not fully elucidated. The aim of the study was to investigate the potential function and molecular mechanism of CASC2 in CRC progression. In this experimental study, quantitative real-time polymerase chain reaction (qRT-PCR) was adopted to probe CASC2, microRNA-18a-5p (miR-18a-5p) and B cell translocation gene 3 (BTG3) mRNA expression in CRC tissues and cell lines. After CASC2 was overexpressed in Colo-678 and HCT116 cell lines, methylthiazol tetrazolium (MTT) and 5-bromo-2'-deoxyuridine (BrdU) assays were employed to examine the proliferation of CRC cells. Transwell migration and invasion assays were executed to evaluate the metastatic potential of CRC cells. The targeting relationships among CASC2, miR-18a-5p and BTG3 were validated by dual luciferase reporter gene assay. Western blot assay was applied to examine the regulatory effects of CASC2 and miR-18a-5p on BTG3 protein expression. CASC2 was decreased in CRC tissues and cell lines, and its low expression in CRC tissues was associated with larger tumor size and lymph node metastasis. CASC2 overexpression restrained proliferative, migrative and invasive capabilities of CRC cells. CASC2 could function as a molecular sponge for miR-18a-5p and repress the expression of miR-18a-5p. Furthermore, the inhibitory effects of CASC2 on the malignant phenotypes of CRC cells was counteracted by miR-18a-5p mimics. Additionally, CASC2 could positively regulate BTG3 expression via suppressing miR-18a-5p. CASC2 inhibits CRC development by suppressing miR-18a-5p and raising BTG3 expression.

Long Noncoding RNA CASC2 Facilitated Wound Healing through miRNA-155/HIF-1α in Diabetic Foot Ulcers.

Diabetic foot ulcers (DFU) are among the serious complications which are closely linked to diabetes mellitus. However, there is still a lack of accurate and effective standard prevention and treatment programs for DFU. In this manuscript, we have investigated the function of lncRNA cancer susceptibility candidate 2 (CASC2)/miR-155/hypoxia-inducible factor 1-alpha (HIF-1α) in the wound healing of DFU. We have analyzed lncRNA CASC2`s expression in the marginal tissues of ulcers in patients and mice with DFU. Additionally, the interaction relationship and mechanism between lncRNA CASC2, miR-155, and HIF-1α were determined, which proved the effects of lncRNA CASC2/miR-155/HIF-1α on fibroblasts apoptosis, proliferation, and migration. According to our study, the lncRNA CASC2's expression was low in the tissues of ulcers of DFU mice and patients. lncRNA CASC2's overexpression promoted fibroblasts migration, proliferation, and inhibited apoptosis and was beneficial for the healing of wounds, preferably in the DFU mice. In addition, lncRNA CASC2 directly targets miR-155 and HIF-1α functions as miR-155's target gene. Overexpression of miR-155 abrogated the function of lncRNA CASC2. Similarly, HIF-1α's inhibition has reversed the effect of miR-155 downregulation on fibroblasts. In general, overexpression of lncRNA CASC2 facilitated wound healing through miR-155/HIF-1α in DFU.

The lncRNA CASC2 Modulates Hepatocellular Carcinoma Cell Sensitivity and Resistance to TRAIL Through Apoptotic and Non-Apoptotic Signaling.

The immune cytokine tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been widely concerned as a tumor therapy because of its ability of selective triggering cancer cell apoptosis; nevertheless, hepatocellular carcinoma (HCC) exhibits acquired resistance to TRAIL-induced apoptosis. In the present study, tumor-suppressive lncRNA cancer susceptibility candidate 2 (CASC2) was downregulated in HCC tissues and cell lines; HCC patients with lower CASC2 expression predicted a shorter overall survival rate. In vitro, CASC2 overexpression dramatically repressed HCC cell proliferation and inhibited cell apoptosis; in vivo, CASC2 overexpression inhibited subcutaneous xenotransplant tumor growth. CASC2 affected the caspase cascades and NF-κB signaling in TRAIL-sensitive [Huh-7 (S) and HCCLM3 (S)] or TRAIL-resistant cell lines [Huh-7 (R) and HCCLM3 (R)] in different ways. In Huh-7 (S) and HCCLM3 (S) cells, CASC2 affected cell apoptosis through the miR-24/caspase-8 and miR-221/caspase-3 axes and the caspase cascades. miR-18a directly targeted CASC2 and RIPK1. In Huh-7 (R) and HCCLM3 (R) cells, CASC2 affected cell proliferation through the miR-18a/RIPK1 axis and the NF-κB signaling. RELA bound to CASC2 promoter region and inhibited CASC2 transcription. In conclusion, CASC2 affects cell growth mainly via the miR-24/caspase-8 and miR-221/caspase-3 axes in TRAIL-sensitive HCC cells; while in TRAIL-resistant HCC cells, CASC2 affects cell growth mainly via miR-18a/RIPK1 axis and the NF-κB signaling. These outcomes foreboded that CASC2 could be a novel therapeutic target for further study of HCC-related diseases.

Long non-coding RNA cancer susceptibility candidate 2 regulates the function of human fibroblast-like synoviocytes via the microRNA-18a-5p/B-cell translocation gene 3 signaling axis in rheumatoid arthritis

ABSTRACT Rheumatoid arthritis (RA) is a perennial inflammatory condition. Preliminary research indicated that long non-coding (lnc)RNA cancer susceptibility candidate 2 (CASC2) was downregulated in the serum of RA patients. Our study was designed to reveal the roles of lncRNA CASC2 in RA and the latent mechanisms underlying its role. Bioinformatics method (Starbase) and dual-luciferase reporter assay revealed that microRNA (miR)-18a-5p directly interacted with lncRNA CASC2. Furthermore, lncRNA CASC2 and miR-18a-5p expression in the serum samples of RA patients and healthy controls were measured via reverse transcription-quantitative PCR. Compared with the healthy subjects, lncRNA CASC2 was downregulated, whereas miR-18a-5p was upregulated in patients with RA. Overexpression of lncRNA CASC2 decreased the viability of human fibroblast-like synoviocytes (HFLSs) and induced apoptosis, as revealed by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and flow cytometry analyses. Furthermore, the Western blotting assay suggested that Bax was upregulated and Bcl-2 was downregulated in lncRNA CASC2 up-regulated HFLSs. Downregulation of tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, IL-6, matrix metalloproteinase (MMP)1, and MMP3 levels by lncRNA CASC2 up-regulation was determined using enzyme-linked immunosorbent assays (ELISAs). However, HFLSs co-transfected with miR-18a-5p mimic exhibited opposite effects compared with the case for the overexpression of lncRNA CASC2. The aforementioned methods were used to verify that a binding site exists between B-cell translocation gene 3 (BTG3) and miR-18a-5p. The effects of miR-18a-5p inhibitor on HFLSs were reversed by BTG3 silencing. Overall, lncRNA CASC2 alleviated RA by adjusting the miR-18a-5p/BTG3 signaling axis and could serve as a novel therapeutic option for RA.

Transcription factor NFIC functions as a tumor suppressor in lung squamous cell carcinoma progression by modulating lncRNA CASC2

ABSTRACT Nuclear factor I (NFI) family is emerging found playing oncogenic or tumor-suppressive potential in cancers. However, the function and underlying mechanisms of NFIC, in the progression of Lung Squamous Cell Carcinoma (LUSC) remain unclear. Therefore, this study aims to probe into the function of NFIC in the development of LUSC. In the present study, we reported that NFIC was low expressed in human LUSC tissues and cell lines. NFIC inhibited LUSC cell proliferation and promoted cell apoptosis in vitro and in vivo. Moreover, NFIC also inhibited LUSC cell migration and invasion. Furthermore, we found that there were binding sites between lncRNA cancer susceptibility candidate 2 (CASC2) and NFIC, whose relationship was confirmed by the luciferase reporter assay. The expression of CASC2 and the expression of NFIC were positively correlated, and the function of CASC2 overexpression is similar to that of NFIC overexpression, which suggested that CASC2 may play a key role in LUSC development. Our study provided a new perspective for NFIC acting as an antioncogene in LUSC tumorigenesis, and NFIC and CASC2 may serve as novel potential targets for the treatment of LUSC.

Long non-coding RNA CASC2 restrains high glucose-induced proliferation, inflammation and fibrosis in human glomerular mesangial cells through mediating miR-135a-5p/TIMP3 axis and JNK signaling

BackgroundDiabetic nephropathy (DN) is a common complication of diabetes. Long non-coding RNA (lncRNA) cancer susceptibility candidate 2 (CASC2) is reported to exert a protective role in DN by a previous study. The working mechanism underlying the protective role of CASC2 in DN progression was further explored in this study.MethodsThe expression of CASC2 and microRNA-135a-5p (miR-135a-5p) was determined by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation ability was assessed by Cell Counting Kit-8 (CCK8) assay and 5-ethynyl-29-deoxyuridine (EDU) assay. Enzyme-linked immunosorbent assay (ELISA) was conducted to analyze the production of inflammatory cytokines in the supernatant. Western blot assay was performed to analyze protein expression. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were performed to verify the target relationship between miR-135a-5p and CASC2 or tissue inhibitors of metalloproteinase 3 (TIMP3).ResultsHigh glucose (HG) treatment reduced the expression of CASC2 in human glomerular mesangial cells (HMCs) in a time-dependent manner. CASC2 overexpression suppressed HG-induced proliferation, inflammation and fibrosis in HMCs. miR-135a-5p was validated as a target of CASC2, and CASC2 restrained HG-induced influences in HMCs partly by down-regulating miR-135a-5p. miR-135a-5p bound to the 3ʹ untranslated region (3ʹUTR) of TIMP3, and CASC2 positively regulated TIMP3 expression by sponging miR-135a-5p in HMCs. miR-135a-5p silencing inhibited HG-induced effects in HMCs partly by up-regulating its target TIMP3. CASC2 overexpression suppressed HG-induced activation of Jun N-terminal Kinase (JNK) signaling partly through mediating miR-135a-5p/TIMP3 signaling.ConclusionsIn conclusion, CASC2 alleviated proliferation, inflammation and fibrosis in DN cell model by sponging miR-135a-5p to induce TIMP3 expression.

LncRNA CASC2 inhibits lung adenocarcinoma progression through forming feedback loop with miR-21/p53 axis.

Lung adenocarcinoma (LUAD) is the most common type of lung cancer. Currently, the survival rate of LUAD patients remains low due to heterogeneity and high invasiveness. The long non-coding RNA (lncRNA) cancer susceptibility candidate 2 (CASC2) is reported to be related to LUAD development. Hence, we investigate the roles and regulatory mechanism of CASC2 in LUAD. The expression levels of CASC2, microRNA (miR)-21, and p53 were quantified by quantitative real-time polymerase chain reaction, and the protein levels of Bax, Bcl-2, p53, and p21 were examined using western blotting. A dual-luciferase reporter experiment was conducted to prove the molecular interactions between CASC2 and miR-21 or p53. CCK-8 and flow cytometry assays were conducted to assess cell proliferation and apoptosis, respectively. CASC2 was expressed at a low level in LUAD patients and LUAD cell lines. CASC2 overexpression markedly suppressed cell proliferation and enhanced apoptosis. Mechanistically, CASC2 overexpression dramatically inhibited miR-21 expression and increased p53 expression by directly targeting miR-21. Moreover, rescue experiments suggested that either miR-21 overexpression or p53 silencing obviously weakened the biological effects of CASC2 overexpression. In addition, p53 was proven to be an upstream transcription factor of CASC2 and can activate CASC2 transcription. These results provide evidence that the lncRNA CASC2/miR-21/p53 form a positive feedback loop to mediate cell proliferation and apoptosis in LUAD, which may provide a new insight into the pathological mechanisms of LUAD.

LncRNA CASC2 Alleviates Sepsis-induced Acute Lung Injury by Regulating the miR-152-3p/PDK4 Axis

ABSTRACT Background: Acute lung injury (ALI) is an early complication of sepsis and it is also considered as an important cause of high mortality in sepsis patients. This research aimed to explore the potential role and mechanism of long non-coding RNA (lncRNA) cancer susceptibility candidate 2 (CASC2) in sepsis-induced ALI. Methods: The levels of CASC2, microRNA-152-3p (miR-152-3p) and pyruvate dehydrogenase kinase 4 (PDK4) in sepsis patients and LPS-treated HPAEpiC were detected by quantitative real-time PCR and western blot. Cell viability and apoptosis were assessed by Counting Kit-8 (CCK-8) assay and flow cytometry. The concentrations of inflammatory factors were tested by Enzyme-linked immunosorbent assay. Oxidative stress was evaluated by the levels of reactive oxygen species and superoxide dismutase using corresponding commercial kits. The targeting relationship between miR-152-3p and CASC2 or PDK4 was verified by dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays. Results: CASC2 and PDK4 were down-regulated, while miR-152-3p was up-regulated in sepsis patients and LPS-stimulated HPAEpiC. Overexpression of CASC2 relieved the LPS-resulted cell viability inhibition, apoptosis promotion, inflammatory and oxidative damages in HPAEpiC. In addition, miR-152-3p was a miRNA target of CASC2 and CASC2 alleviated cell injury in LPS-disposed HPAEpiC by sponging miR-152-3p. Moreover, miR-152-3p directly targeted PDK4 and CASC2 increased the PDK4 expression by depending on the sponge effect on miR-152-3p. Meanwhile, inhibition of miR-152-3p attenuated LPS-triggered HPAEpiC injury by upregulating the level of PDK4. Conclusion: These results suggested that CASC2 ameliorated the LPS-induced injury in HPAEpiC via regulating miR-152-3p/PDK4 pathway.

Long Non-Coding RNA CASC2 Overexpression Ameliorates Sepsis-Associated Acute Kidney Injury by Regulating MiR-545-3p/PPARA Axis

Long non-coding RNAs (lncRNAs) have been demonstrated to be involved in the progression of sepsis-induced acute kidney injury (AKI). In this study, we aimed to explore the functions of lncRNA cancer susceptibility candidate 2 (CASC2) in sepsis-induced AKI. The sepsis cell models were established by exposing HK2 and HEK293 cells into lipopolysaccharide (LPS). Quantitative real-time polymerase chain reaction (qRT-PCR) assay was conducted to determine the expression of CASC2, miR-545-3p and peroxisome proliferator-activated receptor-α (PPARA) mRNA. Cell Counting Kit-8 (CCK-8) assay, flow cytometry analysis and wound healing assay were employed for cell viability, apoptosis and migration, respectively. Western blot assay was conducted for the protein levels of E-cadherin, α-SMA and PPARA. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were measured by specific kits. The relationship between miR-545-3p and CASC2 or PPARA was verified by dual-luciferase reporter assay. CASC2 level was decreased in sepsis patients' serums and LPS-treated HK2 and HEK293 cells. CASC2 overexpression facilitated cell viability and restrained cell apoptosis, migration, epithelial-mesenchymal transition (EMT) and oxidative stress in LPS-triggered HK2 and HEK293 cells. CASC2 was identified as a sponge for miR-545-3p to regulate PPARA expression. MiR-545-3p overexpression restored the impact of CASC2 on LPS-induced injury in HK2 and HEK293 cells. Moreover, miR-545-3p overexpression aggravated LPS-induced cell injury in HK2 and HEK293 cells by targeting PPARA. CASC2 overexpression relieved the damage of HK2 and HEK293 cells mediated by LPS treatment through regulating miR-545-3p/PPARA axis.

LncRNA CASC2 is involved in the development of chronic obstructive pulmonary disease via targeting miR-18a-5p/IGF1 axis.

Aims:Chronic obstructive pulmonary disease (COPD) is a systemic disease. Several long non-coding RNAs (lncRNAs) have been identified to be aberrantly expressed in COPD patients. This study investigated the role of lncRNA cancer susceptibility candidate 2 (CASC2) in COPD, as well as its potential mechanism.Methods:Fifty smokers with COPD and another 50 smokers without COPD were recruited. Receiver operating characteristic curve was constructed to assess the diagnostic value of CASC2 in COPD patients. 16HBE cells were treated with cigarette smoke extract (CSE) to establish a cell model. qRT-PCR was used for the measurement of mRNA levels. The cell viability and apoptosis were detected by using Cell Counting Kit-8 and flow cytometry assay. Enzyme-linked immunosorbent assay was performed to detect the levels of proinflammatory cytokines. Luciferase reporter assay was performed for the target gene analysis.Results:Serum CASC2 was dramatically decreased in COPD patients compared with smokers without COPD, and was positively associated with FEV1 (forced expiratory volume in one second). Serum CASC2 was overexpressed in severe COPD patients, and had the diagnostic accuracy to distinguish COPD patients from smokers. CASC2 overexpression alleviated CSE-induced apoptosis and inflammation in 16HBE cells. CASC2 functions as a ceRNA of miR-18a-5p. Upregulation of miR-18a-5p reversed the influence of CASC2 on cell apoptosis and inflammation in 16HBE cells. IGF1 was the target gene of miR-18a-5p.Conclusion:CASC2 was downregulated in COPD patients and it might be a promising biomarker for the disease diagnosis. Overexpression of CASC2 might inhibit the bronchial epithelial cell apoptosis and inflammation via targeting miR-18a-5p/IGF1 axis.The reviews of this paper are available via the supplemental material section.

LncRNA CASC2 Enhances 131I Sensitivity in Papillary Thyroid Cancer by Sponging miR-155.

Long noncoding RNA cancer susceptibility candidate 2 (CASC2) has been reported to play an anticancer role in papillary thyroid cancer (PTC). Radioiodine (131I) is a common option for the treatment of PTC. However, the role and mechanism of CASC2 in 131I sensitivity remain unclear. In this study, 131I-resistant cells were constructed through continuous treatment of 131I. The expression levels of CASC2 and miR-155 were measured by qRT-PCR. The IC50 of 131I was analyzed by cell viability using MTT assay. Flow cytometry was conducted to determine cell apoptosis induced by 131I. The association between CASC2 and miR-155 was evaluated by luciferase assay and RNA immunoprecipitation. A mouse xenograft model was built to explore the effect of CASC2 on the growth of 131I-resistant PTC cells in vivo. Results showed that CASC2 expression was decreased in PTC tissues and cells, and low expression of CASC2 was associated with poor outcome of patients. CASC2 level was reduced in 131I-resistant cells. Knockdown of CASC2 inhibited 131I sensitivity in thyroid cancer cells. Overexpression of CASC2 enhanced 131I sensitivity in constructed resistant PTC cells. CASC2 was a decoy of miR-155, and CASC2-mediated promotion of 131I sensitivity was weakened by decreasing miR-155. Abundance of CASC2 inhibited the growth of 131I-resistant cells in vivo. As a conclusion, CASC2 increases 131I sensitivity in PTC by sponging miR-155, providing a novel target for the treatment of thyroid cancer patients with 131I resistance.

Long non-coding RNA CASC2 targeting miR-18a suppresses glioblastoma cell growth, metastasis and EMT in vitro and in vivo

Long non-coding RNAs (lncRNAs) cancer susceptibility candidate 2 (CASC2) has been characterized as a tumor suppressor in glioma. Although CASC2 may predict the prognosis of glioma patients, the role and mechanism of CASC2 in human glioblastoma remain to be fully illuminated. Expression of CASC2 and miR- 18a was detected using RT-qPCR. Cell growth was evaluated by MTT assay, colony formation assay, and flow cytometry; metastasis and epithelial-mesenchymal transition (EMT) were determined with transwell assay and Western blot, respectively. The target binding between CASC2 and miR-18a was predicted on Starbase software, and confirmed by luciferase reporter assay and RNA immunoprecipitation. Xenograft experiment measured tumor growth. As a result, CASC2 was downregulated and miR-18a was upregulated in glioblastoma tumor tissues and cells (T98 and A172). Overexpression of CASC2 promoted apoptosis rate and E-cadherin expression, but suppressed cell viability, colony-forming ability, migration, invasion, and expression of N-cadherin and Vimentin in T98 and A172 cells, accompanied with tumor growth inhibition in vivo; whereas, silencing of CASC2 exerted the opposite effect on cell growth, metastasis and EMT of T98 and A172 cells in vitro. However, reintroduction of miR-18a could reverse CASC2 upregulation-mediated suppression on above cell behaviors in vitro. More importantly, miR-18a was a downstream target for CASC2, and was negatively regulated by CASC2. Collectively, this study demonstrated that CASC2 served as tumor suppressor in glioblastoma by inhibiting cell growth, metastasis and EMT both in vitro and in vivo partially via CASC2- miR-18a axis.

Long non-coding RNA CASC2 enhances cisplatin sensitivity in oral squamous cell cancer cells by the miR-31-5p/KANK1 axis.

Oral squamous cell cancer (OSCC) is a primary malignant tumor of the head and neck. Long non-coding RNA cancer susceptibility candidate 2 (CASC2) is related to the chemoresistance of diverse tumors. At present, the resistance of OSCC to first-line chemotherapy drug cisplatin (DDP) is still a giant problem. Herein, we investigated the role and mechanism of CASC2 in OSCC resistance to DDP. Expression levels of CASC2, miR-31-5p, and KANK1 in OSCC tissues and cells were determined by qRT-PCR. The half-maximal inhibitory concentration (IC50) value of DDP-resistant OSCC cells and apoptosis of DDP-resistant OSCC cells were determined via CCK-8 or flow cytometry assays. The relationship between CASC2 or KANK1 and miR-31-5p was verified with a dual-luciferase reporter or RIP assays. The role of CASC2 in vivo was confirmed by xenograft experiments. We observed that CASC2A and KANK1 were downregulated while miR-31-5p was upregulated in DDP-resistant OSCC tissues and cells (p<0.05). CASC2 overexpression enhanced cell DDP sensitivity and accelerated cell apoptosis in DDP-resistant OSCC cells in vivo and in vitro (p<0.05). Notably, KANK1 acted as a target for miR-31-5p. Also, CASC2 modulated KANK1 expression via sponging miR-31-5p in DDP-resistant OSCC cells (p<0.05). Both CASC2 and KANK1 introduction-mediated impacts on the DDP sensitivity and apoptosis of DDP-resistant OSCC cells were restored by miR-31-5p elevation (p<0.05). To conclude, CASC2 boosted the DDP sensitivity and apoptosis of DDP-resistant OSCC cells by upregulating KANK1 via sponging miR-31-5p, and CASC2 might be a potential target for DDP-resistant OSCC treatment.

Long non-coding RNA cancer susceptibility candidate 2 (CASC2) alleviates the high glucose-induced injury of CIHP-1 cells via regulating miR-9-5p/PPAR\u03b3 axis in diabetes nephropathy

BackgroundHigh glucose (HG) induced podocytes injury plays an important role in diabetes nephropathy (DN) development. Long noncoding RNA cancer susceptibility candidate 2 (CASC2) was found to be decreased in serum of DN patients. We aimed to explore the function and possible mechanism of CASC2 in HG induced podocytes injury.MethodsUnder normal glucose (NG), HG and mannitol stimulated podocyte conditions, the levels of CASC2, microRNA-9-5p (miR-9-5p) and peroxisome proliferator-activated receptor gamma (PPARγ) were examined by quantitative real-time polymerase chain reaction (qRT-PCR). Podocyte injury was evaluated by measuring cell viability and apoptosis of CIHP-1 cells were checked by cell counting kit-8 (CCK-8) assay and flow cytometry, respectively. Western blot was used to detect all protein levels. Dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays were performed to confirm the relationship between CASC2 and miR-9-5p.ResultsHG stimulation inhibited the expression levels of CASC2 and PPARγ, but promoted the expression of miR-9-5p. HG could restrain cell viability, autophagy and facilitate apoptosis in CIHP-1 cells, while CASC2 overexpression could reverse HG-induced podocytes injury. Furthermore, CASC2 could be used as a ceRNA to adsorb miR-9-5p, and miR-9-5p mimic overturned the effects of CASC2 on cell viability, autophagy and apoptosis in HG-stimulated podocytes. Additionally, PPARγ was a target gene of miR-9-5p, and CASC2 could weaken the HG-induced podocytes injury by up-regulating PPARγ.ConclusionCASC2 increased cell viability, autophagy and inhibited cell apoptosis by regulating miR-9-5p/PPARγ axis, thus reducing the HG-induced podocytes injury.

LncRNA CASC2 inhibits hypoxia-induced pulmonary artery smooth muscle cell proliferation and migration by regulating the miR-222/ING5 axis

BackgroundPulmonary arterial hypertension (PAH) is often characterized by cell proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs). LncRNA cancer susceptibility candidate 2 (CASC2) has been revealed to be involved in PASMC injury in hypoxia-induced pulmonary hypertension. However, the exact molecular mechanisms whereby CASC2 regulates PASMC proliferation and migration are still incompletely understood.MethodsThe expression levels of CASC2, miR-222 and inhibitor of growth 5 (ING5) were measured using quantitative real-time polymerase chain reaction (qRT-PCR) or western blot, respectively. Cell proliferation was analyzed by Cell Counting Kit-8 (CCK-8) assay. Wound healing assay was used to analyze cell migration ability. The relationship between miR-222 and CASC2 or ING5 was confirmed using bioinformatics analysis, luciferase reporter assay and RNA immunoprecipitation assay.ResultsCASC2 was down-regulated in hypoxia-induced PASMCs in a dose- and time-dependent manner. Functional experiments showed that CASC2 overexpression could reverse hypoxia-induced proliferation and migration of PASMCs. Bioinformatics analysis indicated that CASC2 acted as a competing endogenous RNA of miR-222, thereby regulating the expression of ING5, the downstream target of miR-222, in PASMCs. In addition, rescue assay suggested that the inhibition mediated by CASC2 of hypoxia-induced PASMC proliferation and migration could be attenuated by miR-222 inhibition or ING5 overexpression.ConclusionCASC2 attenuated hypoxia-induced PASMC proliferation and migration by regulating the miR-222/ING5 axis to prevent vascular remodeling and the development of PAH, providing a novel insight and therapeutic strategy for hypoxia-induced PAH.

LncRNA CASC2 downregulation participates in rheumatoid arthritis, and CASC2 overexpression promotes the apoptosis of fibroblast‑like synoviocytes by downregulating IL‑17.

lncRNA cancer susceptibility candidate 2 (CASC2) is a recently identified oncogenic lncRNA in different types of cancers. Our preliminary microarray data showed that lncRNA CASC2 was downregulated in the plasma of patients with rheumatoid arthritis (RA), indicating the involvement of this lncRNA in RA. In the present study, lncRNA CASC2 and IL-17 in plasma were detected by reverse transcription--quantitative PCR and ELISA, respectively. Diagnostic analyses were performed using receiver operating characteristic curves. Flow cytometry was performed to evaluate cell apoptosis. The effects of lncRNA CASC2 on IL-17 expression were determined via western blotting. lncRNA CASC2 was found to be downregulated, while IL-17 was upregulated in the plasma of RA patients when compared with these levels in the plasma of healthy controls. Plasma levels of lncRNA CASC2 and IL-17 were significantly and inversely correlated in both RA patients and healthy controls. Altered plasma levels of lncRNA CASC2 and IL-17 were able to differentiate RA patients from healthy controls. Overexpression of lncRNA CASC2 promoted, while treatment with IL-17 inhibited the apoptosis of human fibroblast-like synoviocytes (HFLSs) isolated from RA patients. Overexpression of lncRNA CASC2 inhibited IL-17 expression in HFLS, while treatment with IL-17 did not significantly affect the expression of lncRNA CASC2. Therefore, downregulation of lncRNA CASC2 is involved in RA and lncRNA CASC2 overexpression may promote the apoptosis of HFLS by downregulating IL-17.

ELF1 activated long non-coding RNA CASC2 inhibits cisplatin resistance of non-small cell lung cancer via the miR-18a/IRF-2 signaling pathway.

Chemoresistance is the leading cause of recurrence in non-small cell lung cancer (NSCLC). The long non-coding RNA (lncRNA) cancer susceptibility candidate 2 (CASC2) inhibits the tumorigenesis of various cancers. However, the regulatory function of CASC2 on the chemoresistance of NSCLC remains unclear. The levels of CASC2 and miR-18a in cisplatin (DDP)-resistant NSCLC tissues and cell lines were evaluated by quantitative Polymerase Chain Reaction (qPCR). The role of low CASC2 levels on overall survival in patients with NSCLC was tested using the log-rank test. The Chi-squared test was used to assess the relation between CASC2 expression and clinicopathological features of NSCLC patients. Cell Counting Kit-8 (CCK-8) assays tested the cell proliferation of cisplatin-resistant NSCLC cells (H226/DDP and A549/DDP). The underlying regulatory mechanism between CASC2 and miR-18a or miR-18a and interferon regulatory factor 2 (IRF-2) was predicted by bioinformatics and verified by a Dual-Luciferase reporter assay, RNA transfection, qPCR, and Western blotting. Chromatin immunoprecipitation (ChIP) assay was done to exam the relation between E74 like factor 1 (ELF1) and CASC2 gene. Mice xenografts were applied to exam the function of CASC2 on chemosensitivity of cisplatin of NSCLC cells in vivo. Low CASC2 expression is more likely to present in patients with advanced TNM stage (IV), cisplatin-resistance, and poor overall survival. The expression of CASC2 sharply decreased in cisplatin-resistant NSCLC tissues and cell lines (H226/DDP and A549/DDP). CASC2 overexpression strongly inhibited proliferation, migration, and invasion of cisplatin-resistant NSCLC cells (H226/DDP and A549/DDP) in vitro and inhibited tumor growth in vivo. Besides, CASC2 repressed miR-18a function by binding to the complementary sites of miR-18a as competing endogenous RNAs (ceRNAs). MiR-18a released by the declining expression of CASC2 reduced the protein concentration of IRF-2 in NSCLC cells. Furthermore, the transcription factor ELF1 was found to be promotor of CASC2 and increased its levels in cisplatin-resistant NSCLC cells. IRF-2 expression mediated by the ELF1/CASC2/miR-18a axis is markedly associated with the proliferation, migration, and invasion of cisplatin-resistant NSCLC, resulting in inferior survival. These findings suggest that this regulatory axis may serve as a novel therapeutic target in NSCLC.

Inflammation and DNA methylation coregulate the CtBP-PCAF-c-MYC transcriptional complex to activate the expression of a long non-coding RNA CASC2 in acute pancreatitis.

Long non-coding RNAs (lncRNAs) are emerging as important regulators involved in the pathogenesis of many diseases. However, it is still unknown if they contribute to the occurrence of acute pancreatitis (AP). Here, we identified a lncRNA CASC2 (Cancer Susceptibility Candidate 2) was significantly upregulated in the pancreatic tissues from AP patients. Knockdown or overexpression of CASC2 in vitro could specifically repress or induce the expression of two proinflammatory cytokines including IL6 (Interleukin 6) and IL17, respectively. Changing the expression levels of several transcription factors that were predicted to bind to the promoter of CASC2, we found c-MYC could specifically regulate the expression of CASC2. Using immunoprecipitation, mass spectrometry, and co-immunoprecipitation assays, we proved that c-MYC assembled a transcriptional complex with PCAF (p300/CBP-associated Factor) and CtBP1/2 (C-terminal Binding Protein 1 and 2), terming as the CtBP-PCAF-c-MYC (CPM) complex. Further investigation revealed that CtBPs were amplified in the pancreatic tissues from AP patients and they functioned as coactivators to induce the expression of CASC2 and thus led to the upregulation of IL6 and IL17. Moreover, we identified that decreased DNA methylation levels in the promoters of CtBPs and inflammatory stimuli coactivated the expression of CtBPs. Collectively, we identified a new signaling pathway in which DNA methylation and inflammatory stimuli coregulate the CPM complex to activate CASC2 expression, whose induction further activates the expression of IL6 and IL17, eventually aggravating inflammation response and causing the pathology of AP.

LncRNA CASC2 Alleviates the Progression of Diabetic Nephropathy by Regulating the miR-144/SOCS2 Signalling Axis

Background: Diabetic nephropathy constitutes a large proportion of end-stage kidney failure in diabetic patients. However, the underlying molecular mechanisms remain unclear. Methods: Db/db diabetic mouse models and high glucose (HG)-induced human renal mesangial cells (HRMCs) were used as research models in vivo and in vitro. The expression of cancer susceptibility candidate 2 (CASC2) was quantified by qRT-PCR. The regulatory role of CASC2 in cell apoptosis, inflammatory factor release, and fibrosis was verified by flow cytometry, qRT-PCR, and Western blot assay, respectively. The bioinformatics prediction software DIANA and starBase v2.0 were used to predict the putative binding sites. The interactions among CASC2, miR-144, and SOCS2 were explored by the luciferase assay and Western bolt assay. Results: The expression of CASC2 in diabetic mouse models and HG-induced HRMCs was lower than that in the control (p < 0.05). Overexpression of CASC2 resulted in a decrease in the apoptosis rate, inflammatory factor release (TNF-α, IL-6, and IL-1β), expression of cleaved caspase-3, and fibrotic proteins (fibronectin, Col-IV, and TGF-β1) and an increase in Bcl-2 expression. Inhibition of CASC2 caused increased expression of miR-144. Furthermore, mechanistic investigations confirmed that activation of the miR-144/SOCS2 regulatory loop by overexpression of miR‐144 reversed the in vitro effects of CASC2 on inhibiting cell apoptosis, inflammatory factor release, and fibrosis. In addition, simultaneous overexpression of miR-144 and SOCS2 further increased the inhibition of cell apoptosis, inflammatory factor release, and fibrosis by CASC2. Conclusion: CASC2 could alleviate the degree and process of apoptosis, inflammation, and fibrosis in diabetic nephropathic models by regulating the miR-144/SOCS2 axis.

Long non‑coding RNA CASC2 suppresses pancreatic cancer cell growth and progression by regulating the miR‑24/MUC6 axis.

Recent evidence indicates that the long non-coding RNA (lncRNA) cancer susceptibility candidate 2 (CASC2) is involved in tumorigenesis of several types of cancer through targeting microRNAs (miRs); however, the molecular mechanism of CASC2 in pancreatic cancer remains elusive. In the present study, the expression levels of CASC2, miR-24 and mucin 6 (MUC6) were measured in pancreatic cancer specimens and cell lines by reverse transcription-quantitative PCR. Western blotting was used to determine the protein expression levels of MUC6, Integrin β4 (ITGB4), phosphorylated (p)-focal adhesion kinase (FAK) and several epithelial-to-mesenchymal transition markers in pancreatic cancer cells. MTT, colony formation, wound healing, Transwell and flow cytometry assays were performed to detect cell proliferation, colony formation, migration, invasion and apoptosis, respectively,in vitro. Morphological changes of pancreatic cancer cells were assessed by light microscopy. The interactions between CASC2, miR-24 and MUC6 were assessed by the dual-luciferase reporter assay. A tumor xenograft model was generated to investigate tumor growth in vivo. CASC2 and MUC6 were downregulated, and miR-24 was upregulated in pancreatic cancer specimens and cell lines. Functionally, CASC2 overexpression or miR-24 knockdown suppressed pancreatic cancer cell proliferation, colony formation, migration and invasion, and promoted apoptosis. Additionally, they altered cell-cell adhesion as demonstrated by the attenuated ITGB4, p-FAK and N-cadherin protein levels, as well as morphological changes. Mechanistically, CASC2 sponged miR-24 and activated its downstream target MUC6 to suppress pancreatic cancer growth and progression. CASC2 exerted tumor-suppressive functions in pancreatic cancer through the miR-24/MUC6 axis, which may be a promising target for pancreatic cancer therapy.