RAD18 promotes cell malignant behaviors of esophageal squamous cell carcinoma by modulating ATM/STAT3/PD-L1.

Background: Esophageal squamous cell carcinoma (ESCC) patients suffer from poor prognosis in general. Novel molecular markers to predict prognosis and serve as potential therapy target are much needed. Our previous research has established a comprehensive database of ESCC (GSE53625). Combined with data from TCGA, we found Pleckstrin 2 (PLEK2) predicts poor prognosis in ESCC. Meanwhile, its role in ESCC progression remains unknown. Methods: The TCGA database and GSE53625 are used to establish the expression profiles of PLEK2 and overall survival rates. Loss-of-function assays were performed to examine the effect of PLEK2 on proliferation, migration and invasion of ESCC cells in vitro and in vivo. ChIP assay was used to detect the relationship between TGF-β and PLEK2. Western blot and quantitative real time PCR (qRT-PCR) were carried out to reveal the interrelation between PLEK2 and LCN2. Results: PLEK2 had a higher expression in ESCCs and predicted poor overall survival (OS). PLEK2 attenuation by shRNA was sufficient to decrease ESCC cells proliferation, clonogenicity, migration and invasion in vitro and tumorigenicity and distant metastasis in vivo. Conversely, elevating PLEK2 levels performed opposite effects. Downregulation of PLEK2 led to higher proportions of apoptotic ESCC cells when induced by Cisplatin. The high expression of PLEK2 in ESCC patients also linked to shorter OS of patients who received adjuvant chemotherapy. TGF-β could increase the expression of PLEK2 by stimulation of Smad2/3 which can bind directly with the promoter sequences of PLEK2. Analyses of transcriptome profiling suggested LCN2 as the downstream of PLEK2. Overexpression LCN2 in PLEK2 stable knockdown ESCC cells can reverse the decreased migration and invasion, but not the proliferation of ESCC cells. TGF-β increased the expression of LCN2, but the effect disappeared when PLEK2 was knockdown. We also find that AKT pathway is involved in the whole regulatory processes. Conclusion: Our results revealed the significance of PLEK2 in driving oncogenesis and metastasis in ESCC by regulating LCN2 which activates AKT pathway. We also indicated that PLEK2 was associated with chemo-resistance. Our findings indicates the potential use of PLEK2 as a prognostic biomarker and a candidate therapeutic target in ESCC. Keywords: PLEK2; ESCC; TGF-β; chemo-resistance Citation Format: Feng Wang, Chaoqi Zhang, Chengming Liu, Hong Cheng, Nan Sun, Jie He. TGF-β induced PLEK2 promotes metastasis and chemoresistance in ESCC by up-regulation of LCN2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1981.

BackgroundFibulin‐4, namely, EFEMP2, is an essential matricellular protein associated with a variety of malignancies. The aim of this study was to explore the role of fibulin‐4 in the progression of esophageal squamous cell carcinoma (ESCC), as well as its effect on ESCC sensitivity to apatinib treatment.MethodsThe expression of fibulin‐4 in ESCC tissues and cell lines was detected. Stably transfected ESCC cells were established by transducing lentiviral vectors for silencing or overexpressing the fibulin‐4 gene into ESCC cells, and a subcutaneous xenograft tumor model of ESCC in mice was successfully established. IHC, RT–qPCR and western blotting were used to detect the expression of related genes and proteins. The CCK8 assay, EdU cell proliferation assay, wound healing assay, transwell assay and flow cytometry were used to evaluate the proliferation, invasion, migration and apoptosis of ESCC cells. After mice were sacrificed, the transplanted tumors were resected, and their volumes were measured.ResultsThe expression of fibulin‐4 was significantly increased in both ESCC tissues and cell lines, and the high expression was closely related to the poor clinicopathological features. Downregulation of fibulin‐4 inhibited the proliferation, invasion and migration of ESCC cells in vitro and in vivo. Meanwhile, fibulin‐4 knockdown inhibited autophagy of tumor cells by activating the Akt–mTOR signaling pathway and significantly promoted apatinib‐induced apoptosis of ESCC cells.ConclusionOur study showed that fibulin‐4 is an oncogene that can promote ESCC progression and inhibit apoptosis. Downregulation of fibulin‐4 enhances the sensitivity of ESCC cells to apatinib by inhibiting cellular protective autophagy through activating the Akt–mTOR signaling pathway.

To investigate the expression, role and the underlying mechanism of miR-124 in esophageal squamous cell carcinoma (ESCC). A total of 25 pairs of ESCC and adjacent tissues were collected for analysis. The human normal esophageal epithelial cell line (Het-1A) and human esophageal cancer cell lines (EC-1) was cultured in Dulbecco's Modified Eagle Medium (DMEM) containing 10% fetal bovine serum (FBS). Cells were transfected with miR-124 mimics and inhibitors. A series of assays, including Cell-Counting-Kit-8 (CCK-8), Transwell migration and invasion assays, real-time quantitative polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay (ELISA) and luciferase reporter gene assay, were performed to detect the effects of miR-124 on ESCC cells. Spearman's correlation analysis was used to evaluate the relationship of miR-124 expression and signal transducer and activator of transcription-3 (STAT3) expression. miR-124 was significantly downregulated in ESCC tissues and cells. Overexpression of miR-124 inhibited the proliferation, migration and invasion of ESCC cells in vitro, while inhibition of miR-124 promoted these processes (all P<0.05). miR-124 was found to specifically bind to the 3'-untranslated region (3'UTR) of STAT3. The expression level of STAT3 was obviously higher in tumor tissues and cells compared to normal adjacent tissues and cells (all P<0.05). Moreover, miR-124 expression was negatively associated with STAT3 levels. Restoring STAT3 expression in ESCC cells transfected with miR-124 mimics partially reversed the inhibitory effects of miR-124 mimics on cell proliferation, migration, and invasion. Conversely, inhibiting STAT3 expression in ESCC cells transfected with miR-124 inhibitors partially abolished the promoting effects of miR-124 inhibitors on the proliferation, migration and invasion of ESCC cells. miR-124 inhibits the proliferation, migration and invasion of ESCC cells by downregulating STATS, indicating that miR-124 may serve as a molecular candidate for treating ESCC.

The aim of this study was to explore the expression of long non-coding ribonucleic acid (lncRNA) nuclear receptor subfamily 2 group F member 1-antisense RNA 1 (NR2F1-AS1) in esophageal squamous cell carcinoma (ESCC) tissues and cells and to investigate its effects on ESCC proliferation and metastasis. The expression level of NR2F1-AS1 in 51 pairs of ESCC tissues and corresponding adjacent tissues was detected via quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR). Meanwhile, NR2F1-AS1 expression in ESCC cells was measured via qRT-PCR as well. Subsequently, specific interference sequences of NR2F1-AS1 were designed, synthesized, and transiently transfected into ESCC cells. 48 h later, qRT-PCR assay was performed to detect the interference efficiency. The effects of small interfering (si)-NR2F1-AS1 on the proliferation of ESCC cells were determined through cell counting kit-8 (CCK-8) and colony formation assay. Wound healing and transwell assays were conducted to investigate the influences of si-NR2F1-AS1 on the migration and invasion of ESCC cells. Additionally, the changes in the expressions of epithelial-mesenchymal transition (EMT) molecular markers were detected by Western blotting. QRT-PCR assay revealed that the expression level of NR2F1-AS1 was significantly up-regulated in 42 of 51 cases of ESCC tissues (42/51, 82.4%). Compared with esophageal mucosal epithelial HET-1A cells, NR2FA-AS1 was highly expressed in ESCC cells. CCK-8 and colony formation assay indicated that the proliferation of ESCC cells decreased remarkably after interference in NR2F1-AS1 expression. The results of wound healing and transwell assays showed that the migration and metastasis of cells were significantly lower in si-NR2F1-AS1 group than those in si-NC group. Western blotting demonstrated that the expressions of EMT molecular markers were changed after interfering with NR2F1-AS1 expression. NR2F1-AS1 was highly expressed in ESCC tissues and cells. Furthermore, high expression of NR2F1-AS1 promoted the proliferation and metastasis of ESCC cells by modulating EMT.

Esophageal squamous cell carcinoma (ESCC) is a type of digestive tract malignant tumor that severely threatens human health. The long non-coding RNA BRAF activated non-coding RNA (BANCR) and insulin-like growth factor 1 receptor (IGF1R) are associated with various types of cancer; however, it remains unclear whether BANCR can regulate IGF1R expression in ESCC. In the present study, the expression levels of BANCR, IGF1R mRNA and microRNA-338-3p (miRNA/miR-338-3p) in ESCC tissues or cells were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The levels of IGF1R, E-cadherin, N-cadherin, Vimentin, p-Raf-1, p-MEK1/2 and p-ERK1/2 were measured by western blot analysis. The proliferation, migration and invasion of ESCC cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetra-zolium bromide (MTT) or Transwell assays. The relationship between miR-338-3p and BANCR or IGF1R was predicted using starBase2.0 and confirmed by dual-luciferase reporter assay. The role of BANCR in ESCC in vivo was confirmed through a tumor xenograft assay. It was found that BANCR and IGF1R were upregulated, while miR-338-3p was down-regulated in ESCC tissues and cells. Both BANCR and IGF1R knockdown suppressed the proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of ESCC cells. IGF1R enhancement reversed BANCR knockdown-mediated effects on the proliferation, migration, invasion and EMT of ESCC cells. BANCR regulated the Raf/MEK/ERK pathway by regulating IGF1R expression. Notably, BANCR regulated IGF1R expression by sponging miR-338-3p. Moreover, BANCR silencing inhibited tumor growth in vivo. On the whole, the findings of the present study demonstrate that BANCR inhibition blocks ESCC progression by inactivating the IGF1R/Raf/MEK/ERK pathway by sponging miR-338-3p.

Esophageal squamous cell carcinoma(ESCC) is a common histologic subtype in China. It has been suggested that abnormal expression of microRNAs(miRNAs) is associated with carcinogenesis. We investigated miR-126 expression and its potential targets in ESCC. The expression of miR-126 was detected in cancerous and paired paracancer tissues from 102 patients with ESCC. Target analysis of miR-126 was predicted using online tools. The effect of miR-126 expression on target proteins was assessed using miR-126 mimics or miR-126 inhibitors in ESCC cell lines. In addition, the impact of miR-126 on cell proliferation, apoptosis, migration and invasion was detected in ESCC cell lines. The expression of miR-126 was significantly lower in ESCC tissues, which was associated with tumor differentiation, lymph node metastasis, tumor in-depth and TNM stage. Insulin receptor substrate-1 (IRS-1) and Golgi phosphoprotein 3(GOLPH3) were overexpressed in ESCC. Overexpression of IRS-1 was associated with cell differentiation, whereas GOLPH3 was related to lymph node metastasis, tumor invasion in-depth and TNM stage in ESCC patients. miR-126 mimics downregulated the expression of IRS-1 and GOLPH3 protein and suppressed the proliferation, migration and invasion of ESCC cells, whereas miR-126 inhibitors led to the opposite results. miR-126 suppressed the proliferation, migration and invasion of ESCC cells, and acted as a tumor suppressor in the carcinogenesis of ESCC. IRS-1 and GOLPH3 are downstream targets of miR-126 at the post-transcriptional level in ESCC.

Background: Exosome plays an important role in cell communication and cell environment. But the mechanism of how exosome derived from cancer-associated fibroblast (CAF) influent esophageal squamous cell carcinoma (ESCC) progression is not clear. In this work, compared with normal fibroblast-derived exosomes (NDEs), we found that CAF derived exosomes (CDEs) can enhance the growth, migration, and invasion of ESCC cells obviously. Therefore, we would like to clarify the role of CDEs in ESCC progression. Methods and Results: Using microRNA array to analyze the different miRNAs in the CDEs and NDEs, we got a series of up-regulation miRNAs and two down-regulation miRNAs in CDEs. Among them, miR-3656 shows a significantly highest level. Then, we transfected miR-3656 mimics to the ESCC cells and found the mimics increased the growth, migration, and invasion of ESCC cells in cell proliferation assay. cell scratch tests and chamber invasion experiments. We established recombinant ESCC cells with miR-3656 high expression by the lentiviral system. The cells were injected into mice to form the xenograft tumor. The results showed the miR-3656 can enhance the tumor formation. After that, aided by TargetScan software, we found ACAP2, one of miR3656 targets, was significantly down-regulating in ESCC cells at the high level of miR-3656. When ACAP2 expression was knocked-down by siRNA, the proliferation and migration of ESCC cells was increased, which indicated ACAP2 a potential anti-tumor factor. Furthermore, we detected the different proteins between ESCC cells with high expression miR-3656 and normal ESCC cells through LC_MS; the results were analyzed by Integrate Pathway Analysis (IPA) system and many differential proteins were found to be involved of PI3K/AKT and Wnt pathways. Conclusions: In this study, we found the CDEs promote the progression of their sounding ESCC cells in vitro and in vivo. The main reason is that CDEs carry some tumor-promoting miRNAs that influent the target ESCC cells. Especially, miR-3656 expresses the highest level of miRNAs in CDEs. It not only decreases the expression of ACAP2 but also impacts the expression of proteins involved PI3K/AKT and Wnt pathways in ESCC cells. The results indicate the CDEs playing a very important role in ESCC progression. Citation Format: Xiaojia Chen, Yuan Jin, Bihui Zhang, Xiaocen LI, Baoqing Tian, Qiang Wang, An Hong. Exosome from CAF-ESCC aggravates tumor progression by its containing molecular miR-3656 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1987.

Long noncoding RNA (lncRNA) small nucleolar RNA host gene 6 (SNHG6) has been shown to be upregulated in esophageal squamous cell carcinoma (ESCC). However, its detailed function in ESCC remains unknown. We investigated its specific roles in ESCC cell proliferation, invasion, and migration. Gene expression was evaluated by quantitative reverse transcriptase polymerase chain reaction and western blot. The subcellular localization of lncRNA SNHG6 was determined using subcellular location assay. Luciferase reporter assay and RNA pull-down assay were applied to determine the interaction between lncRNA SNHG6, miR-186-5p, and hypoxia-inducible factor 1α (HIF1α). The cell proliferation, migration, and invasion abilities were evaluated by using cell count kit-8, colony formation assay, and transwell migration and invasion assays. LncRNA SNHG6 and HIF1α were upregulated, while miR-186-5p was downregulated in ESCC tissues and cell lines. Knockdown of lncRNA SNHG6 inhibits ESCC cell proliferation, migration, and invasion. A negative correlation between lncRNA SNHG6 and miR-186-5p expression was found in ESCC tissues. Similarly, there is a positive correlation between lncRNA SNHG6 and HIF1α expression in ESCC tissues. Conversely, miR-186-5p expression was negatively correlated with HIF1α expression in ESCC tissues. Furthermore, lncRNA SNHG6 was identified as a decoy for miR-186-5p, thereby promoting the expression of miR-186-5p target HIF1α. More significantly, restoration of SNHG6 or HIF1α could reverse the inhibitory effect of miR-186-5p on ESCC cell proliferation, migration, and invasion. Downregulation of SNHG6 inhibited the proliferation, migration, and invasion of ESCC cells through regulating miR-186-5p/HIF1α axis, providing a novel therapeutic target for ESCC.

Tumor-associated macrophages (TAMs) contribute to the progression and mortality of various malignancies. We reported that high numbers of infiltrating TAMs were significantly associated with tumor progression and poor prognosis in esophageal squamous cell carcinoma (ESCC). In our previous investigation of TAMs' actions in ESCC, we compared gene expression profiles between peripheral blood monocyte (PBMo)-derived macrophages and TAM-like macrophages stimulated with conditioned media of ESCC cell lines. Among the upregulated genes in the TAM-like macrophages, we focused on CC chemokine ligand 3 (CCL3), which was reported to contribute to tumor progression in several malignancies. Herein, we observed that not only TAMs but also ESCC cell lines expressed CCL3. A CCL3 receptor, CC chemokine receptor 5 (CCR5) was expressed in the ESCC cell lines. Treating the ESCC cell lines with recombinant human (rh)CCL3 induced the phosphorylations of Akt and ERK, which were suppressed by CCR5 knockdown. Migration and invasion of ESCC cells were promoted by treatment with rhCCL3 and co-culture with TAMs. TAMs/rhCCL3-promoted cell migration and invasion were suppressed by inhibition of the CCL3–CCR5 axis, PI3K/Akt, and MEK/ERK pathways. Treatment with rhCCL3 upregulated MMP2 and VEGFA expressions in ESCC cell lines. Our immunohistochemical analysis of 68 resected ESCC cases showed that high expression of CCL3 and/or CCR5 in ESCC tissues was associated with poor prognosis. High CCR5 expression was associated with deeper invasion, presence of vascular invasion, higher pathological stage, higher numbers of infiltrating CD204+ TAMs, and higher microvascular density. High expression of both CCL3 and CCR5 was an independent prognostic factor for disease-free survival. These results suggest that CCL3 derived from both TAMs and cancer cells contributes to the progression and poor prognosis of ESCC by promoting cell migration and invasion via the binding of CCR5 and the phosphorylations of Akt and ERK. The CCL3–CCR5 axis could become the target of new therapies against ESCC.The authors. show that CCL3 derived from both tumor-associated macrophages and esophageal squamous cell carcinoma (ESCC) cells promotes cell migration and invasion of ESCC cells via binding CCR5. High expression of CCL3 and/or CCR5 associates with poor prognosis in ESCC patients. CCL3–CCR5 axis could be a specific target of anti-cancer therapy.

Objective: Integrins have been shown to play an important role in the tumorigenesis of many cancers. In this work, we aimed to explore the expression and clinical value of Integrin α5β1 in esophageal squamous cell carcinoma (ESCC), and the effect of integrin β1 on the development and chemo-resistance of ESCC cells.Methods: The expression profiling of integrins was analyzed in the mRNA expression dataset of ESCC. The expression of Integrin α5β1 in 278 cases of ESCC tissues and 62 cases of paracancerous tissues was detected by immunohistochemistry (IHC). The association between the expression of Integrin α5β1 and the survival of ESCC patients was analyzed by Kaplan-Meier analysis. The effect of Integrin β1 on the proliferation, migration, and invasion of ESCC cells was examined by MTS, Transwell migration, and Transwell invasion assay. The effect of Integrin β1 and L1 cell adhesion molecule (L1CAM) on cisplatin resistance was detected by MTS and the signal pathways involved were analyzed by Western blotting.Results: Integrin β1 and Integrin α5 were significantly up-regulated in ESCC. High expression of Integrin β1 was also related to worse overall survival of ESCC patients and patients with low levels of both Integrin β1 and Integrin α5 showed the shortest survival. Results of IHC revealed that Integrin α5β1 was up-regulated in ESCC and its high expression was associated with poor prognosis and could serve as an independent prognostic factor. siRNA-mediated Integrin β1 silencing or antibody blocking restrained the proliferation, migration, and invasion of ESCC cells. Simultaneous knockdown of Integrin β1 and L1CAM reduced the cisplatin resistance of ESCC cells. Further studies showed that knockdown of Integrin β1 and L1CAM suppressed the activity of Akt signaling with or without cisplatin treatment. Moreover, dual high expression of Integrin β1 and L1CAM was related to worse overall survival of ESCC patients treated with preoperative chemotherapy.Conclusion: Integrin α5β1 was up-regulated in ESCC and could be used as a new prognostic indicator for ESCC patients. In addition, Integrin β1 was involved in the proliferation, invasion, and chemo-resistance of ESCC cells.

Simple SummaryLncRNA JPX acts as an oncogenic regulator in various types of cancer. Here, we present insights into the mechanistic evidence for the function of JPX in ESCC progression. To clarify the potential role of JPX in ESCC, JPX was upregulated or downregulated in ESCC cells, and in a xenograft model. We showed that JPX promoted ESCC cell proliferation, migration, and invasion via the miR-516b-5p/VEGFA pathway. Our study revealed the importance of JPX as a promising biomarker for ESCC diagnosis and therapeutic target for ESCC in clinic.Long non-coding RNAs (lncRNAs) are reported act as important regulators in various types of cancer. LncRNA JPX was identified as an oncogenic regulator in lung cancer. However, the function of JPX in the progression of esophageal squamous cell carcinoma (ESCC) remains unclear. In the present study, we found JPX was highly expressed in esophageal tissue from ESCC patients. Functional assays demonstrated that JPX promoted ESCC cell proliferation, migration, and invasion in vitro, and accelerated tumor growth in vivo. Mechanistically, the results showed that JPX functioned as a sponge of miR-516b-5p, which targeted vascular endothelial growth factor A (VEGFA) in ESCC cells. Interactions between miR-516b-5p and JPX or VEGFA were confirmed by luciferase reporter assays. Inhibition of JPX significantly attenuated the cell growth and mobility ability of ESCC cells in vitro. In addition, overexpression of miR-516b-5p abrogated JPX-enhanced proliferation, migration, invasion, and angiogenesis of ESCC cells. Our study demonstrated that JPX played an important role in promoting ESCC progression via the miR-516b-5p/VEGFA pathway, which might serve as a promising novel diagnostic biomarker and therapeutic target for ESCC in clinic.

E2F1-activated NRSN2 promotes esophageal squamous cell carcinoma progression through AKT/mTOR pathway

This study aimed to investigate RING-Finger Protein 6 (RNF6) expression in esophageal squamous cell carcinoma (ESCC) cells and whether it affects cell proliferation, invasion, and migration by regulating the TGF-β1/c-Myb pathway. TCGA database was used to analyze RNF6 expression in normal tissues and esophageal cancer tissues. Kaplan-Meier method was used to examine the correlation between RNF6 expression and patient prognosis. SiRNA interference vector and RNF6 overexpression plasmid were constructed, and RNF6 was transfected into Eca-109 and KYSE-150 esophageal cancer cell line. In vitro scratch assay and Transwell assay were conducted to investigate the effects of RNF6 on the migration and invasion of Eca-109 and KYSE-150 cells. RT-PCR detected the expression of Snail, E-cadherin, and N-cadherin, and TUNEL detected the apoptosis of cells. RNF6 up-regulation promoted the progression of esophageal cancer and predicted poor prognosis. RNF6 also enhanced the migration and invasion of ESCC cells in vitro. RNF6 silencing inhibited the migration and invasion of ESCC cells. TGF-β inhibitors reversed the oncogenic effects of RNF6. RNF6 regulated the migration and invasion of ESCC cells by activating the TGF-β pathway. RNF6/TGF-β1 promoted esophageal cancer progression through c-Myb. RNF6 promotes the proliferation, invasion, and migration of ESCC cells possibly by activating the TGF-β1/c-Myb pathway and affects the progression of ESCC.

Long intergenic non-coding RNA 01232 (LINC01232) was identified as a critical regulator of the development of pancreatic adenocarcinoma. The present study investigated the expression and regulatory roles of LINC01232 in esophageal squamous cell carcinoma (ESCC). The main aim of the present study was to elucidate the underlying mechanisms through which LINC01232 affects the malignancy of ESCC. Initially, LINC01232 expression in ESCC was analyzed using the TCGA and GTEx databases and was confirmed using reverse transcription-quantitative polymerase chain reaction. ESCC cell proliferation, apoptosis and migration and invasion were assessed using the Cell Counting kit-8 assay, flow cytometric analysis, and migration and invasion assays, respectively. ESCC tumor growth in vivo was examined using a xenograft mouse model. As shown by the results, a high LINC01232 expression was detected in ESCC tissues and cell lines. LINC01232 downregulation suppressed the proliferation, migration and invasion of ESCC cells, and promoted cell apoptosis in vitro. In addition, LINC01232 depletion restricted tumor growth in vivo. Mechanistically, LINC01232 was shown to function as an microRNA-654-3p (miR-654-3p) sponge in ESCC cells, and hepatoma-derived growth factor (HDGF) was identified as a direct target of miR-654-3p. LINC01232 could bind competitively to miR-654-3p and decrease its expression in ESCC cells, thereby promoting HDGF expression. Rescue experiments reconfirmed that the effects of LINC01232 deficiency in ESCC cells were restored by increasing the output of the miR-654-3p/HDGF axis. On the whole, the present study demonstrates that LINC01232 plays a tumor-promoting role during the progression of ESCC by regulating the miR-654-3p/HDGF axis. The LINC01232/miR-654-3p/HDGF pathway may thus provide a novel theoretical basis for the management of ESCC.

LncRNA CASC15 has been determined as a novel tumor-related lncRNA in many cancers. However, the in-detail role of CASC15 remains elusive in esophageal squamous cell carcinoma (ESCC). CASC15 expression level was detected in 113 ESCC tissues and paired adjacent normal tissues and in human ESCC cell lines. The effects of CASC15 on ESCC proliferation, migration, and invasion were assessed using CCK-8 and transwell assays. In addition, the potential downstream molecules of CASC15 were searched and confirmed by software algorithms, RT-qPCR, western blot, dual-luciferase reporter, and rescue experiments. CASC15 was upregulated in ESCC tissues and cell lines. CASC15 overexpression was associated with poorer prognosis in ESCC patients. Functionally, CASC15 knockdown inhibited cell proliferation, migration, and invasion of ESCC cells. Mechanistically, it was confirmed that CASC15 acts as competing endogenous RNA for miR-33a-5p to regulate PTGS2 expression. In addition, rescue assay showed that miR-33a-5p knockdown or PTGS2 overexpression abolished the cell proliferation, migration, and invasion inhibition role of CASC15 knockdown. In conclusion, this study indicates that CASC15 was upregulated in ESCC and CASC15 knockdown hindered ESCC progression through targeting the miR-33a-5p/PTGS2 axis. CASC15 might serve as a novel biomarker and therapeutic target for ESCC.