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Esophageal cancer is a complex malignancy and the sixth leading cause of cancer death worldwide. In Eastern Asia including China, about 90% of all incident cases have esophageal squamous cell carcinoma (ESCC). Mounting evidence elucidates that aberrant expression of various non-coding RNAs (ncRNAs) contributes to ESCC progression, but it remains unclear how small nucleolar RNAs (snoRNAs) are involved in ESCC development. We systemically screened clinically relevant snoRNAs in ESCC via integrative analyses of The Cancer Genome Atlas (TCGA) data and validation in ESCC tissues. We found that snoRNA SNORD12B was one of the most evidently upregulated snoRNAs in ESCC specimens and its high expression was significantly associated with poor prognosis of patients. SNORD12B profoundly promoted proliferation, migration, invasion, and metastasis of ESCC cells in vitro and in vivo, indicating its oncogene nature. In particular, SNORD12B could interact with PP-1α, one of the three catalytic subunits of serine/threonine protein phosphatase 1, which is a major phosphatase that directly dephosphorylates AKT to suppress its activation. Interestingly, high levels of SNORD12B in ESCC cells could break interactions between 14-3-3ζ and PP-1α, abolish the retention of PP-1α in the cytosol by 14-3-3ζ and relocate PP-1α from the cytosol to the nucleus. This led to sequestered PP-1α in the nucleus, enhanced phosphorylation of AKT in the cytosol, activated AKT-mTOR-4EBP1 signaling, and, thus, ESCC progression. These insights would improve our understanding of how snoRNAs contribute to tumorigenesis and highlight the potential of snoRNAs as future therapeutic targets against cancers.

BackgroundLung cancer has become a global health issue in recent decades. Despite of high rate of resistance, cisplatin-base chemotherapy is still the main treatment of lung cancer patients who are not suitable for TKI-based targeted therapy and immunotherapy. Thus, overcoming cisplatin resistance is urgently needed.MethodsA small panel is established to screen chemicals and compounds overcoming cisplatin resistance. Survival fractions as well as proliferation are determined by MTT assay. Colony formation assay, JC-1 assay, EdU assay, ROS assay as well as apoptosis and cell cycle assay are performed to verify vitalities of different groups. Quantifications of NADP+/NADPH and GSH/GSSG are carried out according to standard protocols. Xenograft model is generated to evaluate the in vivo role of APR-246.ResultsIn this study, we identify NADPH metabolism and reactive oxygen species (ROS) levels as the main cause accounting for cisplatin resistance of H460. Based on a small panel consisting common chemotherapy drugs and compounds, APR-246 is proved an effective compound specifically inhibiting proliferation and colony formation of cisplatin resistant H460 (H460-Cis) cells. APR-246 significantly causes G0/G1 accumulation and S phase inhibition of H460-Cis cells. Besides, APR-246 can obviously lead to severe mitochondria dysfunction as well as elevated apoptosis by altering apoptosis-related protein expressions in H460-Cis cells. Further study proves that it is the aberrant ROS levels as well as NRF2/SLC7A11/GSH axis dysfunction accounting for the specific anti-tumor effects of APR-246. Mechanistically, NRF2 is specifically ubiquitylated degraded in APR-246 treated H460-Cis cells, which in turn decrease NRF2/SLC7A11/GSH axis activity.ConclusionOur study uncovered new insights into the biology driving cisplatin resistance of lung cancer and highlights potentials of APR-246 as future therapeutic agents again cisplatin resistance.

Fibroblast growth factors (FGFs) and their receptors (FGFRs) modulate a wide range of biological functions, especially tumor genesis. The aim of this study was to investigate the possible association of FGFR expression with the susceptibility of digestive system and reproductive system cancers in Chinese population. In total, 343 patients with digestive or reproductive system cancers were enrolled in this study. The expression levels of four highly-conserved FGFRs including FGFR1, FGFR2, FGFR3 and FGFR4 were measured by immunohistochemistry (IHC). The expression levels of FGFRs were compared between carcinoma and para-carcinoma tissues. FGFR1 expression significantly differed between carcinoma and para-carcinoma tissues in colon and gastric cancers. FGFR2 expression significantly differed between carcinoma and para-carcinoma tissues in esophageal cancer. FGFR3 expression was significantly different between carcinoma and para-carcinoma tissues in liver and gastric cancers. FGFR2 showed the highest expression probability in all the selected cancers and FGFR4 showed the lowest expression probability. FGFR1 and FGFR3 showed comparable moderate expression probabilities. Our findings have demonstrated significant differences regarding FGFR expression levels between carcinoma and para-carcinoma cells in digestive or reproductive system cancer patients. The data also implicated that FGFR2 and FGFR4 could serve as two prominent factors closely related to the susceptibility of digestive and reproductive system cancers.

Cancer-associated fibroblasts (CAFs) are believed to influence tumor behavior and clinical outcomes. We previously showed that conditioned medium (CM) from CAFs induces proliferation and motility of esophageal squamous cell carcinoma (ESCC) cells. Here, we investigated the molecular mechanisms by which the CAF-secreted proteins induce ESCC development and progression. Using antibody arrays, we identified urokinase plasminogen activator (uPA) as one of the main proteins whose release was increased in CAFs compared to normal fibroblasts (NFs). Immunohistochemical analysis of pathological sections showed that uPA-positive cells were localized at the boundaries of tumor and stroma tissues, in stroma between tumor nests, and within the tumors. Increased stromal uPA levels (132/146 cases) correlated with tumor invasion (p < 0.05) and overall survival of ESCC patients (p < 0.05). In vitro assays showed that uPA promotes ESCC cell proliferation, migration, and invasion via PI3K/AKT and ERK signaling pathways. In vivo, anti-uPA antibody suppressed tumor growth in ESCC xenografts. These results suggest that uPA released from stroma, and especially from CAFs, might be a predictive marker for ESCC diagnosis and prognosis, as well as an effective therapeutic target.

Resistance to platinum-based combination chemotherapy is the main cause of poor prognosis in patients with advanced esophageal squamous cell carcinoma (ESCC). Previously, we showed that CACNA2D3 (voltage-dependent subunit alpha 2 delta 3 of a calcium channel complex) was significantly downregulated and functioned as a tumor suppressor in ESCC, but its role in the chemosensitivity of ESCC to cisplatin remained unknown. Here, we found that the expression of CACNA2D3 was significantly associated with poor platinum response in ESCC patients from the Gene Expression Omnibus database. Overexpression of CACNA2D3 increased sensitivity to cisplatin in ESCC in vitro, whereas knockdown of CACNA2D3 increased cisplatin resistance. CACNA2D3 promoted cisplatin-induced apoptosis by modulating intracellular Ca2+ stores. In vivo experiments further showed that overexpression of CACNA2D3 enhanced cisplatin anti-tumor effects in a xenograft mouse model. CACNA2D3 overexpression also resulted in the attenuation of PI3K and Akt phosphorylation. Treatment with the PI3K/Akt inhibitor LY294002 restored the chemosensitivity of CACAN2D3-knockdown cells to cisplatin. In conclusion, the results of the current study indicate that CACAN2D3 enhances the chemosensitivity of ESCC to cisplatin via inducing Ca2+-mediated apoptosis and suppressing PI3K/Akt pathways. Therefore, regulating the expression of CACNA2D3 is a potential new strategy to increase the efficacy of cisplatin in ESCC patients.

Esophageal cancer is the eighth most common malignant tumor worldwide, of which esophageal squamous cell carcinoma (ESCC) is the dominant histological subtype. A drug shortage for ESCC therapy triggered us to explore the roles of fibroblast growth factor receptor 2 (FGFR2) and its upstream regulator miR-671-5p in ESCC progression. We compared the levels of FGFR2 and miR-671-5p between human ESCC tissues and their matched normal esophageal tissues and found an association between higher levels of FGFR2 and lower levels of miR-671-5p in ESCC tissues. High levels of FGFR2 resulted in the activation of the ERK and AKT pathways and a promotion of ESCC progression. High levels of miR-671-5p specifically reduced the expression of FGFR2 and suppressed ESCC progression in both in vitro and in vivo models. Therefore, suppressing FGFR2 and enhancing miR-671-5p expression may be the right approaches for ESCC therapy.

The current study aimed to explore the functions and roles of microRNA-193b (miR-193b) in the myocardium with ischemia-reperfusion (I/R) injury and a potential therapeutic method for myocardial I/R injury. The mice were subjected to myocardial I/R with or without miR-193b pretreatment. The infarct size and myocardial enzymes were detected. The terminal deoxynucleotidyl transferase dUTP nick-end labeling assay was conducted to investigate the effect of miR-193b on cardiomyocyte apoptosis. The expression levels of miR-193b and mastermind-like 1 (MAML1) were validated by quantitative real-time polymerase chain reaction and Western blot analysis. The results suggested that the miR-193b expression level was significantly downregulated in the myocardium with I/R injury compared with control group. miR-193b overexpression is able to reduce infarct size and myocardial enzymes after myocardial I/R injury. Furthermore, overexpression of miR-193b could alleviate the apoptosis level after myocardial I/R injury. Taken together, the present study demonstrated that upregulated miRNA-193b alleviated myocardial I/R injury via targeting MAML1.

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.

Small interfering RNAs (siRNA)/microRNAs (miRNA) have promising therapeutic potential, yet their clinical application has been hampered by the lack of appropriate delivery systems. Herein, we employed extracellular vesicles (EVs) as a targeted delivery system for small RNAs. EVs are cell-derived small vesicles that participate in cell-to-cell communication for protein and RNA delivery. We used the aptamer AS1411-modified EVs for targeted delivery of siRNA/microRNA to breast cancer tissues. Tumor targeting was facilitated via AS1411 binding to nucleolin, which is highly expressed on the surface membrane of breast cancer cells. This delivery vesicle targeted let-7 miRNA delivery to MDA-MB-231 cells in vitro as confirmed with fluorescent microscopic imaging and flow cytometry. Also, intravenously delivered AS1411-EVs loaded with miRNA let-7 labeled with the fluorescent marker, Cy5, selectively targeted tumor tissues in tumor-bearing mice and inhibited tumor growth. Importantly, the modified EVs were well tolerated and showed no evidence of nonspecific side effects or immune response. Thus, the RNAi nanoplatform is versatile and can deliver siRNA or miRNA to breast cancer cells both in vitro and in vivo. Our results suggest that the AS1411-EVs have a great potential as drug delivery vehicles to treat cancers.

Esophageal cancer is the world's tenth common malignant tumor. Esophageal cancer is divided into esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (ECA). ESCC is the dominant histological subtype. The overall 5-year survival rate for people with advanced-stage of ESCC is only about 10%-20%, but ESCC is still not well-studied. Therefore, it is very important to study the mechanism of cancer progression in ESCC in order to develop new therapies for this deadly disease. Fibroblast growth factor receptor2 (FGFR2) is one of the RTK members and generally regarded as an oncogene, but little is known about its function in ESCC. In our study, we proved FGFR2 played the key role in ESCC progression. From In vitro studies, overexpression of FGFR2 promoted the ESCC cells' migration, invasion, and proliferation, which was confirmed through knocking down FGFR2 in ESCC cells. In vivo xenograft tumor mouse model studies showed the tumor size from ESCC cells with FGFR2 over-expression larger than that of the control group. Conversely, the tumor size from ESCC cells with FGFR2 knock-down was significantly smaller compared with the control group. Molecular mechanism studies showed that overexpression of FGFR2 activated the ERK and AKT signal pathways and altered the cell cycle in ESCC. In addition, decreased expression of miR-671-5p was identified by microRNA array and QPCR verify assay in ESCC–FGFR2+ tissue. Using a dual influence report system, we confirmed miR-671-5p could regulate expression of FGFR2. It was also found that FGFR2 was highly expressed whereas miR-671-5p was expressed at a low level in most of the FGFR2-positive ESCC clinic samples. Furthermore, we demonstrated that miR-671-5p could inhibit the proliferation and metastasis of ESCC cells in vitro and it could suppress growth of ESCC in vivo. The miR-671-5p suppressed MAPK and PI3K signal pathways through down-regulation of phosphorylation of FGFR2. Therefore, miR-671-5p was seen as a tumor suppressor in ESCC. Our results demonstrated that FGFR2 and miR-671-5p are potential therapeutic targets in ESCC. They both participate in the progression of ESCC, but also play the contrasting roles. Antagonists of FGFR2 or activators of miR-671-5p could be therapeutics against ESCC. Citation Format: Xiaojia Chen, Xiaoyan Li, Baoqing Tian, Xuan Tan, Wei Han, Jiakang Wang, An Hong. FGFR2 and miR-671-5p as key participants involved in the progression of human esophageal squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2520.