ZNF468 inhibits irradiation-induced G2/M cell cycle arrest and apoptosis by facilitating AURKA transcription in Esophageal Squamous Cell Carcinoma.

BACKGROUND: ZNF468 is a relatively unexplored gene that has been implicated in potential oncogenic properties in various cancer types. However, the exact role of ZNF468 in radiotherapy resistance of esophageal squamous cell carcinomas (ESCCs) is not well understood. METHODS: Bioinformatic analysis was performed using the TCGA database to assess ZNF468 expression and prognostic significance in pan-cancer and ESCC. Functional experiments were conducted using ZNF468 overexpressing and knockdown cell lines to assess its impact on cell survival, DNA damage response, cell cycle, and apoptosis upon radiation. A luciferase reporter assay was utilized to validate ZNF468 binding to the AURKA promoter. RESULTS: ZNF468 was significantly upregulated in diverse cancer types, including ESCC, and its high expression correlated with adverse prognosis in specific tumors. In the ESCC cohort, ZNF468 exhibited substantial upregulation in post-radiotherapy tissues, indicating its potential role in conferring radiotherapy resistance. Functional experiments revealed that ZNF468 enhances cell viability and facilitates DNA damage repair in radiotherapy-treated ESCC cells, while dampening the G2/M cell cycle arrest and apoptosis induced by radiation. Moreover, ZNF468 facilitated AURKA transcription, resulting in upregulated Aurora A expression, and subsequently inhibited P53 expression, unveiling key molecular mechanisms underlying radiotherapy resistance in ESCC. CONCLUSION: ZNF468 plays an oncogenic role in ESCC and contributes to radiotherapy resistance. It enhances cell survival while dampening radiation-induced G2/M cell cycle arrest and apoptosis. By modulating AURKA and P53 expression, ZNF468 represents a promising therapeutic target for enhancing radiotherapy efficacy in ESCC.

Delivery of miR-26a Using an Exosomes-Based Nanosystem Inhibited Proliferation of Hepatocellular Carcinoma.

Background: MicroRNA (abbreviated miRNA)-based treatment holds great promise for application as clinical antitumor therapy, but good carriers for delivery of the miRNA drug are lacking. Exosomes secreted by mesenchymal stem cells (MSCs) have proved to be safe, and exogenously modified exosomes may potentially represent an excellent drug delivery vehicle. Methods: In this study, we designed a delivery nano system using single-stranded variable fragment (scFv)-modified exosomes derived from human cord blood MSCs. Genetic engineering technology was used to obtain anti-Glypican 3 (GPC3) scFv-modified exosomes, which were then loaded with miR-26a mimics through electroporation. Results: Results of electron microscopy and dynamic light scattering indicated that the diameter of the drug-carrying exosomes was about 160 nm. Furthermore, anti-GPC3 scFv-modified exosomes effectively delivered miR-26a to GPC3-positive hepatocellular carcinoma cells, thereby inhibiting cell proliferation and migration by regulating the expression of downstream target genes of miR-26a. The exosomes-based nano system displayed favorable anti-tumor effect in vivo with no obvious side effects. Conclusion: Our data provided a new perspective for the use of exosome delivery systems for miRNA-based antitumor therapy.

The Tumorigenic Properties of EZH2 are Mediated by MiR-26a in Uveal Melanoma.

Background: The polycomb group protein enhancer of zeste homolog 2 (EZH2) has been found to be highly expressed in various tumors, and microRNA-26a (miR-26a) is often unmodulated in cancers. However, the functions of these two molecules in uveal melanoma (UM) and their relationships have not been reported. Methods: We explored the effects of the miR-26a-EZH2 axis in UM by examining the levels of miR-26a and EZH2. The EZH2 levels in various tumor types and the correlations between EZH2 levels and overall survival and disease-free survival were reanalyzed. The binding of miR-26a to the 3'-untranslated region of EZH2 mRNA was measured using the luciferase reporter assay. The regulation of EZH2 gene expression by miR-26a was also identified, and the effect of elevated EZH2 expression on UM cell function was further examined. Results: miR-26a was downregulated and EZH2 was upregulated in UM cells. Overexpression of miR-26a inhibited cell proliferation, and knockdown of EZH2 suppressed cell growth. EZH2 was a direct target of miR-26a in UM cells. The knockout of EZH2 mimicked the tumor inhibition of miR-26a in UM cells, whereas the reintroduction of EZH2 abolished this effect. In addition, a network of EZH2 and its interacting proteins (UBC, CDK1, HDAC1, SUZ12, EED) was found to participate in miR-26a-mediated tumor progression. Conclusion: The newly identified miR-26a-EZH2 axis may be a potential target for the development of treatment strategies for UM.

MiR-27a-3p enhances the cisplatin sensitivity in hepatocellular carcinoma cells through inhibiting PI3K/Akt pathway.

MicroRNAs (miRNAs) play an important role in drug resistance, and it is reported that miR-27a-3p regulated the sensitivity of cisplatin in breast cancer, lung cancer and ovarian cancer. However, the relationship between miR-27a-3p and chemosensitivity of cisplatin in hepatocellular carcinoma (HCC) was unclear, especially the underlying mechanism was unknown. In the present study, we analyzed miR-27a-3p expression levels in 372 tumor tissues and 49 adjacent tissues in HCC samples from TCGA database, and found that the miR-27a-3p was down-regulated in HCC tissues. The level of miR-27a-3p was associated with metastasis, Child-Pugh grade and race. MiR-27a-3p was regarded as a favorable prognosis indicator for HCC patients. Then, miR-27a-3p was overexpressed in HepG2 cell, and was knocked down in PLC cell. Next, we conducted a series of in vitro assays, including MTT, apoptosis and cell cycle assays to observe the biological changes. Further, inhibitor rate and apoptosis rate were detected with pre- and post-cisplatin treatment in HCC. The results showed that overexpression of miR-27a-3p repressed the cell viability, promoted apoptosis and increased the percentage of cells in G0/G1 phase. Importantly, overexpression of miR-27a-3p significantly increased the inhibitor rate and apoptosis rate with cisplatin intervention. Besides, we found that miR-27a-3p added cisplatin sensitivity potentially through regulating PI3K/Akt signaling pathway. Taken together, miR-27a-3p acted as a tumor suppressor gene in HCC cells, and it could be useful for modulating cisplatin sensitivity in chemotherapy.

Role of phosphatidylinositol 3-kinase signaling pathway in radiation-induced liver injury.

Transforming growth factor-ß1 (TGF-ß1) is one of critical cytokines in radiation-induced liver injury. Hepatic stellate cells (HSC) are activated in the early stage of radiation-induced liver injury. However, it is currently unclear whether phosphatidylinositol 3-kinase (PI3K/Akt) signal pathway is activated in radiation-induced liver injury. Herein, male Sprague-Dawley rats were irradiated with 6 MV X-rays (30 Gy) on the right liver. Next, Hematoxylin and eosin staining, Masson staining, and electron microscopy were performed to examine pathological changes. Immunohistochemistry was performed to assess the expression of TGF-ß1, α-SMA, and p-Akt (S473) in liver tissues. In vitro, rat HSC cell line HSC-T6 cells were given different doses of 6 MV X-ray irradiation (10 and 20 Gy) and treated with LY294002. The expression of α-SMA and p-Akt in mRNA and protein levels were measured by reverse transcription-polymerase chain reactioin (RT-PCR) and Western blot. TGF-ß1 expression was detected by enzyme-linked immuno sorbent assay (ELISA). After irradiation, the liver tissues showed obvious pathological changes, indicating the establishment of the radiation-induced liver injury. Expression levels of TGF-ß1, α-SMA, and p-Akt (S473) protein in liver tissues were significantly increased after irradiation, and this increase was in a time-dependent manner, suggesting the activation of HSC and PI3K/Akt signal pathway. in vitro experiments showed that the TGF-ß1 secreted by HSCs, and the expression of Akt and α-SMA at mRNA and protein levels were significantly increased in irradiation groups. However, the expression of TGF-ß1, Akt, and α-SMA were significantly decreased in PI3K/Akt signal pathway inhibitor LY294002-treated group. Our results suggest that during radiation-induced liver injury, HSCs are activated by TGF-ß1-mediated PI3K/Akt signal pathway.

Downregulation of microRNA-519 enhances development of lung cancer by mediating the E2F2/PI3K/AKT axis.

MicroRNA-519 (miR-519) acts as an inhibitor in different kinds of tumors. The current study was set to probe the function of miR-519 in lung cancer and to explore the potential molecular mechanism. The expression difference of miRNAs between lung cancer and paracancerous tissues was analyzed by microarray. miR-519 expression was significantly diminished in lung cancer tissues and cells. After that, EdU staining, CCK-8 assay, Transwell assay, Hoechst 33258 staining and PI/Annexin-V staining revealed that overexpression of miR-519 in lung cancer cells inhibited their viability and promoted apoptosis. TragetScan and miRSearch were employed to predict the target mRNAs of miR-519, which were verified by a luciferase activity assay. miR-519 bound to the 3'untranslated region of E2F transcription factor 2 (E2F2) mRNA. Finally, the extent of PI3K/AKT signaling pathway phosphorylation was examined, which illustrated that upregulation of miR-519 repressed the phosphorylation of the PI3K/AKT pathway in SPC-A-1 and 95C cells. miR-519 reduces PI3K/AKT pathway activities by suppressing the transcription activity of E2F2, thereby potentially inhibiting the occurrence of lung cancer.

TMPRSS4 promotes cancer stem cell traits by regulating CLDN1 in hepatocellular carcinoma.

Encouraging advances in the treatment of hepatocellular carcinoma(HCC) have been achieved; however, a considerable part of patients still relapse or metastasize after therapy, and the underlying mechanisms have not been clarified yet. Here, we found that CLDN1 was markedly up-regulated in HCC tissues, and correlated with poor prognosis. Overexpression of CLDN1 dramatically promoted the capability of tumorsphere formation and cancer stem cell (CSC) traits. Furthermore, we found that TMPRSS4 was up-regulated in HCC tissues and there was a positive correlation between TMPRSS4 and CLDN1. In addition, the expression of CLDN1 was regulated by TMPRSS4. Moreover, TMPRSS4 mediated CSC properties and up-regulated CLDN1 by activating ERK1/2 signaling pathway. Taken together, our results revealed that CLDN1 contributed to CSC features of HCC, which was altered by TMPRSS4 expression via ERK1/2 signaling pathway, providing promising targets for novel specific therapies.

miR-29a suppresses growth and migration of hepatocellular carcinoma by regulating CLDN1.

CLDN1 (claudin1) is essential for intercellular junctions and has been reported to be involving in cell migration and metastasis, making it as an oncogene in various cancer types. However, the biological function roles and regulatory mechanisms of CLDN1 in hepatocellular carcinoma (HCC) are still not clarified. In this study, we found down-regulation of miR-29a and up-regulation of CLDN1 in HCC tissues and cell lines. Further found an inverse relation between the expressions of miR-29a and CLDN1 in HCC. Dual-luciferase reporter assay indicated that miR-29a regulated the expression of CLDN1 by binding to its 3' untranslated region (3'UTR). Knockdown of CLDN1 led to decrease in tumor cell growth and migration capacities in vitro and in vivo. While overexpression of miR-29a suppressed tumor growth and migration, these effects could be reversed by re-expressing CLDN1. Taken together, out data suggested that miR-29a may regulate tumor growth and migration by targeting CLDN1, providing promising therapeutic targets for HCC.