Qianqian Sun

Knockdown of long non-coding RNA TP73-AS1 inhibits cell proliferation and induces apoptosis in esophageal squamous cell carcinoma.

Recent studies have shown that long non-coding RNAs (lncRNAs) are involved in a variety of biological processes and diseases in humans, including cancer. Our study serves as the first comprehensive analysis of lncRNA TP73-AS1 in esophageal cancer. We utilized a lncRNA microarray to analyze the expression profile of lncRNAs in esophageal squamous cell carcinoma. Our results show that lncRNA TP73-AS1 and BDH2 levels are generally upregulated in esophageal cancer tissues and are strongly correlated with tumor location or TNM stage in clinical samples. LncRNA TP73-AS1 knockdown inhibited BDH2 expression in EC9706 and KYSE30 cells, whereas BDH2 knockdown repressed esophageal cancer cell proliferation and induced apoptosis via the caspase-3 dependent apoptotic pathway. Overexpression of BDH2 in lncRNA TP73-AS1 knockdown cells partially rescued cell proliferation rates and suppressed apoptosis. In mouse xenografts, tumor size was reduced in lncRNA TP73-ASI siRNA-transfected tumors, suggesting that downregulation of lncRNA TP73-AS1 attenuated EC proliferation in vitro and in vivo. In addition, BDH2 or lncRNA TP73-AS1 knockdown enhanced the chemosensitivity of esophageal cancer cells to 5-FU and cisplatin. Our results suggest that lncRNA TP73-AS1 may be a novel prognostic biomarker that could serve as a potential therapeutic target for the treatment of esophageal cancer.

LncRNA UCA1-miR-507-FOXM1 axis is involved in cell proliferation, invasion and G0/G1 cell cycle arrest in melanoma.

Recently, the incidence of melanoma has been on the rise. Patients with distant metastasis share poor prognosis. Increasing studies have been conducted to clarify the molecular mechanisms as well as to investigate potential effective therapeutic targets in the development of melanoma. This study focuses on the LncRNA UCA1 and its downstream regulated factors. In our experiments, UCA1 expression was discovered to be upregulated in melanoma tissues and cells, while the depletion of UCA1 led to the inhibition of cell proliferation, invasion and cell cycle arrest. To further our understanding of the mechanisms of UCA1, a system of experiments was built. We found that miR-507 could directly bind to UCA1 at the miRNA recognition site, and that there was a negative correlation between miR-507 and UCA1. Additionally, FOXM1 is a target of miR-507 and can be downregulated by either miR-507 overexpression or UCA1 depletion. Downregulated FOXM1 was analogous to the depletion of UCA1 and the overexpression of miR-507. These results, taken together, provide evidence for a novel UCA1 interaction regulatory network in tumorigenesis of melanoma.

Myricetin inhibits proliferation and induces apoptosis and cell cycle arrest in gastric cancer cells

Myricetin is a flavonoid that is abundant in fruits and vegetables and has protective effects against cancer and diabetes. However, the mechanism of action of myricetin against gastric cancer (GC) is not fully understood. We researched myricetin on the proliferation, apoptosis, and cell cycle in GC HGC-27 and SGC7901 cells, to explore the underlying mechanism of action. Cell Counting Kit (CCK)-8 assay, Western blotting, cell cycle analysis, and apoptosis assay were used to evaluate the effects of myricetin on cell proliferation, apoptosis, and the cell cycle. To analyze the binding properties of ribosomal S6 kinase 2 (RSK2) with myricetin, surface plasmon resonance (SPR) analysis was performed. CCK8 assay showed that myricetin inhibited GC cell proliferation. Flow cytometry analysis showed that myricetin induces apoptosis and cell cycle arrest in GC cells. Western blotting indicated that myricetin influenced apoptosis and cell cycle arrest of GC cells by regulating related proteins. SPR analysis showed strong binding affinity of RSK2 and myricetin. Myricetin bound to RSK2, leading to increased expression of Mad1, and contributed to inhibition of HGC-27 and SGC7901 cell proliferation. Our results suggest the therapeutic potential of myricetin in GC.

miR-198 targets SHMT1 to inhibit cell proliferation and enhance cell apoptosis in lung adenocarcinoma

MiR-198 is involved in tumorigenesis, migration, invasion, and metastasis of various malignant cancers. However, the exact expression levels of miR-198 and the molecular mechanism underlying its role in lung adenocarcinoma require further exploration. In this study, quantitative real-time PCR was applied to study miR-198 and serine hydroxymethyltransferase 1 (SHMT1) expression in 47 paired lung adenocarcinoma tissues and adjacent nontumor lung tissues. Clinicopathological characters were analyzed. Pearson’s correlation analysis was used to detect the relationship between miR-198 and SHMT1 expression. The function of miR-198 was explored by measuring cell proliferation, cell apoptosis, and the cell-cycle in vitro and in vivo. The target gene of miR-198 was certified using dual luciferase report assay. We found that in lung adenocarcinoma, miR-198 was significantly downregulated and SHMT1 was inversely upregulated. A strong negative correlation was noticed between miR-198 and SHMT1 expression. Further analysis revealed that miR-198 expression was associated with TNM stage and lymph node metastasis. Upregulated miR-198 could inhibit cell proliferation, enhance cell apoptosis, and lead to cell-cycle arrest in lung adenocarcinoma, which showed a more effective alteration than SHMT1 siRNA. Moreover, we identified SHMT1 as a target gene of miR-198. In conclusion, miR-198 suppressed proliferation of lung adenocarcinoma cells both in vitro and in vivo by directly targeting SHMT1. miR-198 may be a potential therapeutic target for lung adenocarcinoma in the near future.

Sodium Butyrate Upregulates miR-203 Expression to Exert Anti-Proliferation Effect on Colorectal Cancer Cells.

Background: As the end product of the bacterial fermentation of dietary fiber in the colonic lumen, sodium butyrate (NaBt) has been reported to exert antitumor effects on colorectal cancer (CRC). In addition to functioning as a histone deacetylase (HDAC) inhibitor, NaBt also regulates the expression of microRNAs (miRNAs) to inhibit CRC cell proliferation. Yet, the mechanisms involved are not completely understood. Here we investigate whether NaBt regulates miR-203 to inhibit CRC growth and explore the promising target gene of miR-203 in CRC cells. Methods: We conducted qRT-PCR and Western blotting assays to evaluate the effects of NaBt on the expression of miR-203 and NEDD9 in HT-29 and Caco-2 cell lines. The promising target gene of miR-203 was predicted by miRNA target prediction and dual luciferase reporter assay. CRC Cell proliferation, colony formation, cell apoptosis and cell invasion assays were performed to explore the effect of NaBt, miR-203 and NEDD9 on HT-29 and Caco-2 cell lines. Results: The results showed that NaBt increased the expression of miR-203 to induce CRC cell apoptosis as well as inhibit cell proliferation, colony formation and cell invasion. Moreover, we determined that the NEDD9 was a target gene of miR-203. NEDD9 partially overcame the inhibitory effects of miR-203 on CRC cell colony formation and invasion. Conclusions: NaBt could induce CRC cell apoptosis, inhibit CRC cell proliferation, colony formation and invasion through miR-203/NEDD9 cascade. The present study may enrich the mechanisms underlying the process that NaBt exerts anti-tumor effects on CRC cells.

Long Noncoding RNA RGMB-AS1 Indicates a Poor Prognosis and Modulates Cell Proliferation, Migration and Invasion in Lung Adenocarcinoma

Lung cancer is the most common cause of cancer-related mortality worldwide. It is a complex disease involving multiple genetic and epigenetic alterations. The development of transcriptomics revealed the important role of long non-coding RNAs (lncRNAs) in lung cancer occurrence and development. Here, microarray analysis of lung adenocarcinoma tissues showed the abnormal expression of lncRNA RGMB-AS1. However, the role of lncRNA RGMB-AS1 in lung adenocarcinoma remains largely unknown. We showed that upregulation of lncRNA RGMB-AS1 was significantly correlated with differentiation, TNM stage, and lymph node metastasis. In lung adenocarcinoma cells, downregulation of lncRNA RGMB-AS1 inhibited cell proliferation, migration, invasion, and caused cell cycle arrest at the G1/G0 phase. In vivo experiments showed that lncRNA RGMB-AS1 downregulation significantly suppressed the growth of lung adenocarcinoma. The expression of lncRNA RGMB-AS1 was inversely correlated with that of repulsive guidance molecule b (RGMB) in lung adenocarcinoma tissues, and UCSC analysis and fluorescence detection assay indicated that lncRNA RGMB-AS1 may be involved in the development of human lung adenocarcinoma by regulating RGMB expression though exon2 of RGMB. In summary, our findings indicate that lncRNA RGMB-AS1 may play an important role in lung adenocarcinoma and may serve as a potential therapeutic target.

Anticancer function of α-solanine in lung adenocarcinoma cells by inducing microRNA-138 expression

Currently, lung cancer is still a main cause of malignancy-associated death worldwide. Even though various methods for prevention and treatment of lung cancer have been improved in recent decades, the 5-year survival rate has remained very low. Insights into the anticancer function of small-molecule anticancer compounds have opened our visual field about cancer therapy. α-Solanine has been well studied for its antitumor properties, but its effect in lung cancer and associated molecular mechanisms have not yet been evaluated. To explore the anticancer function of α-solanine, we performed an MTT assay, Transwell arrays, colony-forming survival assay, quantitative reverse transcription PCR (qRT-PCR), Western blotting, and dual luciferase reporter assays in A549 and H1299 cells. We found that α-solanine not only inhibited cell migration and invasion ability but also enhanced the chemosensitivity and radiosensitivity of A549 and H1299 cells. Moreover, we discovered that α-solanine could affect the expression of miR-138 and focal adhesion kinase (FAK), both of which were also found to affect the chemosensitivity and radiosensitivity of A549 and H1299 cells. In conclusion, α-solanine could affect miR-138 and FAK expression to restrict cell migration and invasion and enhance the chemosensitivity and radiosensitivity of A549 and H1299 cells. The α-solanine/miR-138/FAK cascade can probably be a potential therapy target against lung adenocarcinoma.

MiR-499 Enhances the Cisplatin Sensitivity of Esophageal Carcinoma Cell Lines by Targeting DNA Polymerase β

Background: Human DNA polymerase β (DNA polymerase β, polβ) is a small monomeric protein essential for short-patch base excision repair (BER). It plays an important role in regulating the sensitivity of tumor cells to chemotherapy. Methods: Luciferase reporter and western blot assays were used to determine whether polβ is a major target of miR-499. CCK-8, colony-forming survival and in vivo tumor growth assays were conducted to evaluate if miR-499 can potentially enhance the cisplatin sensitivity and therefore inhibit the proliferation of esophageal cancer (EC) cells. Flow cytometry and immunofluorescence microscopy assays were performed to evaluate whether miR-499 enhance the cisplatin sensitivity and the corresponding apoptosis in EC cells. Results: polβ was pinpointed as a target gene of miR-499. Additionally, we identified that miR-499 can enhance cisplatins function of inhibiting proliferation and of promoting apoptosis in EC9706 and KYSE30 cell lines. Conclusions: We first investigated whether miR-499 modulates polβ, and observed the influence of miR-499 up-regulation on the sensitivity of EC cell lines to cisplatin treatment. Our study paves the way for more insightful understanding and application of chemotherapy in esophageal cancer in the future.

α-Solanine Modulates the Radiosensitivity of Esophageal Cancer Cells by Inducing MicroRNA 138 Expression.

Background: Esophageal cancer (EC) is one of the most common malignant tumors in the world. Due to difficulties with performing the operation, most patients choose to have palliative treatment instead. Radiotherapy is one of the main palliative treatments of EC. However, the clinical efficacy of radiotherapy is not satisfactory α-Solanine is a bioactive component of steroidal glycoalkaloids which has been demonstrated to exhibit anti-metastasis activity in different cancers. In the present study, we determined the effect of α-solanine on the radiosensitivity of EC cells and priliminarily explored the underlying molecular mechanisms. Methods: Cell Counting Kit-8 (CCK-8) assay was conducted to found the cytotoxic effect of α-solanine on EC cells. CCK-8 assay and colony-forming survival assays were performed to explore the effect of α-solanine on cell viability and proliferation of EC cells after irradiation. Immunofluorescence and comet assays were used to detect the effect of α-solanine on DNA repair capacity of EC cells after irradiation. The flow cytometry (FCM) and Hoechst/PI staining were conductd to study the effect of α-solanine on apoptosis of EC cells after irradiation. Results: The cytotoxic effect of α-solanine to EC cells was dose-dependent. The results of CCK-8, colony-forming survival assay, immunofluorescence, comet assay, FCM and Hoechst/PI staining showed that α-solanine could enhance the radiosensitivity of EC cells. α-Solanine could downregulate Survivin expression level by upregulating miR-138 expression in EC cells. Upregulation of miR-138 and knock down Survivin both enhanced the radiosensitivity of EC cells. Moreover, Survivin could restore the effect of α-solanine and miR-138 on radiosensitivity of EC cells. Conclusions: α-solanine could enhance the radiosensitivity of esophageal cancer cells by inducing microRNA-138 expression, and probably be an effective radiosensitizer in treating EC.

A novel dual-luciferase assay for anti-HIV drug screening based on the CCR5/CXCR4 promoters

Acquired immunodeficiency syndrome (AIDS) is a serious worldwide disease caused by infection with the human immunodeficiency virus (HIV). C-C chemokine receptor 5 (CCR5) and C-X-C chemokine receptor 4 (CXCR4) are important coreceptors mediating HIV-1 cell entry. Many new anti-HIV drugs are currently in preclinical and clinical trials; however, drug development has proceeded slowly partly because of the lack of a high-throughput system to screen these drugs. Here, we describe the development of a novel dual-luciferase assay using a CCR5/CXCR4 promoter-driven firefly and Renilla luciferase vector (pGL4.10-RLUC-CCR5/CXCR4). Drugs were screened for the ability to regulate CCR5 and CXCR4 promoter activities. The CCR5 and CXCR4 promoters were inserted separately into the recombinant vector and transfected into the acute T lymphocyte leukemia cell line H9. Treatment of stable transfected cells with four traditional Chinese medicine compounds resulted in the dose-dependent inhibition of the CXCR4 and CCR5 promoter activities. The dual-luciferase reporter assay provides a rapid and direct method to screen anti-AIDS/HIV drugs.