Background/Aims: Circular RNAs (circRNAs), a type of RNA that is widely expressed in human cells, have essential roles in the development and progression of cancer. CircRNAs contain microRNA (miRNA) binding sites and can function as miRNA sponges to regulate gene expression by removing the inhibitory effect of an miRNA on its target gene. Methods: We used the bioinformatics software TargetScan and miRanda to predict circRNA-miRNA and miRNAi-Mrna interactions. Rate of inhibiting of proliferation was measured using a WST-8 cell proliferation assay. Clone formation ability was assessed with a clone formation inhibition test. Cell invasion and migration capacity was evaluated by performing a Transwell assay. Relative gene expression was assessed using quantitative real-time polymerase chain reaction and relative protein expression levels were determined with western blotting. circRNA and miRNA interaction was confirmed by dual-luciferase reporter and RNA-pull down assays. Results: In the present study, the miRNA hsa-miR-21-5p was a target of circRNA-ACAP2, and T lymphoma invasion and metastasis protein 1 (Tiam1) was identified as a target gene of hsa-miR-21-5p. CircRNA-ACAP2 and Tiam1 were shown to be highly expressed in colon cancer tissue and colon cancer SW480 cells, but miR-21-5p was expressed at a low level. SW480 cell proliferation was suppressed when the expression of circRNA-ACAP2 and Tiam1 was decreased and the expression of miR-21-5p was increased in vivo and in vitro. SW480 cell migration and invasion were also inhibited under the same circumstance. The circRNA-ACAP2 interaction regulated the expression of miR-21-5p, and miR-21-5p regulated the expression of Tiam1. Down-regulation of circRNA-ACAP2 promoted miR-21-5p expression, which further suppressed the transcription and translation of Tiam1. Conclusion: The present study shows that the circRNA-ACAP2/hsa-miR-21-5p/Tiam1 regulatory feedback circuit could affect the proliferation, migration, and invasion of colon cancer SW480 cells. This was probably due to the fact that circRNA-ACAP2 could act as a miRNA sponge to regulate Tiam1 expression by removing the inhibitory effect of miR-21-5p on Tiam1 expression. The results from this study have revealed new insights into the pathogenicity of colon cancer and may provide novel therapeutic targets for the treatment of colon cancer.

Prostate cancer gene expression marker 1 (PCGEM1) is a long non-coding RNA (lncRNA) overexpressed in prostate cancer (PCa) cells that promotes PCa initiation and progression, and protects against chemotherapy-induced apoptosis. The microRNA miR-145 functions as a tumor suppressor in PCa. We speculate that reciprocal regulation of PCGEM1 and miR-145 promote proliferation of LNCaP prostate cancer cells. To test this hypothesis, the interaction between PCGEM1 and miR-145 was examined using a luciferase reporter assay. Expression levels were selectively altered in LNCaP cells and noncancerous RWPE-1 prostate cells by transfection of miR-145 or small interfering RNA sequences against (siRNA) PCGEM1. Relative expression levels were detected by RT-PCR, tumor cell growth and early apoptosis by the MTT assay and flow cytometry, respectively, and tumor cell migration and invasion properties by transwell assays. The effect of siRNA PCGEM1 and miR-145 transfection on prostate cancer growth in vivo was examined in the (nu/nu) mouse model. PCGEM1 and miR-145 exhibited reciprocal regulation; downregulation of PCGEM1 expression in LNCaP cells increased expression of miR-145, while overexpression of miR-145 decreased PCGEM1 expression. Transfection of the miR-145 expression vector and siRNA PCGEM1 inhibited tumor cell proliferation, migration, and invasion, and induced early apoptosis both in vitro. In contrast, there was no effect on RWPE-1 cells. We demonstrate a reciprocal negative control relationship between PCGEM1 and miR-145 that regulates both LNCaP cell proliferation and nu/nu PCa tumor growth. The results also identify PCGEM1 and associated regulators as possible targets for PCa therapy.

B-cell lymphoma 2 (Bcl-2) is a regulator protein involved in apoptosis. In the past few decades, this protein has been demonstrated to have high efficacy in cancer therapy, and several approaches targeting Bcl-2 have been tested clinically (e.g., oblimersen, ABT-737, ABT-263, obatoclax mesylate, and AT-101). This review reports potential Bcl-2 inhibitors according to current information on their underlying mechanism and the results of clinical trials. In addition, the function and mechanisms of other potentially valuable Bcl-2 inhibitors that did not show efficacy in clinical studies are also discussed. This summary of the development of Bcl-2 inhibitors provides worthwhile viewpoints on the use of biomedical approaches in future cancer therapy.

The aim of this study was to investigate the effect of a eukaryotic expression vector expressing hsa-miR-203 on the sensitivity of K562 leukemia cells to arsenic trioxide (ATO) and the possible mechanism of action. The eukaryotic expression vector expressing the hsa-miR-203 plasmid (PmiR-203) was transfected into K562 cells using Lipofectamine 2000. bcr/abl 3′ untranslated region (UTR) and bcr/abl mutated 3′UTR dual luciferase report vectors (psi-CHECK-2) were used to validate the regulation of bcr/abl by miR-203. The inhibitory effects of ATO and PmiR-203, used singly or in combination, on cell proliferation were detected by MTT assay. Apoptosis of the K562 cells was detected by flow cytometry using double-staining with Annexin V and propidium iodide (PI). The activities of caspase-3 and caspase-9 were detected by a colorimetric method and the cytochrome c protein levels were detected by western blotting. When used in combination with PmiR-203, the IC50 of ATO was reduced from 6.49 to 2.45 μg/ml and the sensitivity of cells to ATO increased 2.64-fold. In addition, PmiR-203 and ATO caused growth inhibition, apoptosis and G1-phase arrest in K562 cells. Furthermore, PmiR-203 significantly promoted ATO-mediated growth inhibition and apoptosis, affecting the G1 phase. JC-1 fluorescent staining revealed that the membrane potential of the mitochondria had changed. The activities of caspase-3 and caspase-9 increased, the expression levels of cytochrome c were upregulated and the expression level of bcr/abl mRNA was significantly suppressed. Furthermore, the dual-luciferase reporter vector, containing tandem miR-203 binding sites from the bcr/abl 3′UTR, demonstrated that bcr/abl was directly regulated by miR-203. PmiR-203 sensitized K562 leukemia cells to ATO by inducing apoptosis and downregulating bcr/ abl gene levels. The induction of apoptosis may occur through the mitochondrial pathway. The combination of ATO and PmiR-203 presents therapeutic potential for chronic myelogenous leukemia.

Nasopharyngeal carcinoma (NPC) is a major cause of cancer deaths. Concurrent administration of radiation and chemotherapy is the treatment of choice for advanced NPC. Previously, we showed that apogossypolone (ApoG2) induced apoptosis by blocking the binding of Bcl-2 to Bax, arresting the cell cycle in the S phase, in turn inhibiting proliferation of NPC cells both in vitro and in vivo. In the present study, we showed that ApoG2 inhibited the proliferation of NPC cells in a dose-dependent manner. We treated CNE1, CNE2 and SUNE1 cells with ApoG2 for 72 h, and calculated the IC50 values as 2.84, 5.64 and 2.18 µM, respectively. Normal NP69 cell proliferation was not significantly inhibited. ApoG2 treatment induced significant autophagy, demonstrated by an increase in LC3-II protein expression, reduced protein p62 expression, and accumulation of punctuate GFP-LC3 in the cytoplasm of CNE1 or CNE2 cells. Sh-Atg5 attenuated the autophagy induced by ApoG2, indicating that Atg5 was required for ApoG2-induced autophagy. In addition, ApoG2 treatment blocked the binding of Bcl-2 to Beclin 1 protein, releasing pro-autophagic Beclin 1, which in turn triggered the autophagic cascade. Colony formation assays indicated that ApoG2 enhanced radiosensitization of CNE2 cells. In the ApoG2-plus-radiation combination group, more ring-shaped structures were evident in CNE1 and CNE2 cultures. LC3-II expression was enhanced and that of p62 reduced, compared to the ApoG2-only, radiation-only and control groups. ApoG2 enhanced the radiosensitivity of CNE2 xenografts in nude mice as measured by (C-T)/C ratios (as percentages); the values for the ApoG2 and radiation groups were 46.89% and 19.34%, respectively. The ApoG2-plus-radiation group exhibited greater antitumor activity (the inhibitory rate was 61.64%). Immunohistological staining showed that LC3-II expression became gradually upregulated in the ApoG2-plus-radiation group. Together, the results suggest that ApoG2 inhibits the binding of Bcl-2 to Beclin 1, inducing autophagy and radio-sensitizing NPC cells both in vitro and in vivo.

Background/Aims: Recently, rapidly accumulating evidence has shown that microRNAs (miRNAs) are involved in human tumorigenesis, and the dysregulation of miRNAs has been observed in many cancers, including prostate cancer. miR-145-5p, an miRNA with reduced expression in prostate cancer cells, has been shown to have a tumor suppressive role in a variety of tumors. However, its underlying mechanism requires further elucidation. Methods: A lentiviral expression vector for miR-145-5p was constructed and used to establish a stable cell line (LNCaP) expressing miR-145-5p. The cells were cultured normally and divided into the control group (control), negative control group (negative control), and test group (miR-145-5p). Inhibition of proliferation was measured by a WST-8 assay. The early apoptosis rate of cells was detected by flow cytometry. Clone formation ability was detected by a clone formation inhibition test. Cell invasion and migration capacity was detected by a Transwell assay. The relative expression levels of proteins were detected by western blotting. We constructed a nude mouse model of prostate cancer to observe the effect of miR-145-5p on the growth of transplanted tumors. TargetScan bioinformatics software was used to predict target genes regulated by miR-14-5p. ChIPBase was used to predict transcription factors with binding sites in the upstream promoter region of miR-145-5p. Quantitative reverse transcription PCR was used to detect the relative expression level of genes. A bifluorescence-reporter gene vector was constructed to confirm the regulation of target genes by miR-145-5p. We used 5′ rapid amplification of cDNA ends to confirm the transcription start site of miR-145-5p.Chromatin immunoprecipitation technology was used to detect the effect of transcription factors binding to miR-145-5p. Results: The overexpression of miR-145-5p not only inhibited the proliferation, invasion, and migration of LNCaP cells but also promoted their early apoptosis. After overexpressing miR-145-5p, the expression of small ubiquitin-like modifier protein-specific protease 1 (SENP1), and caudal-related homeobox 2 (CDX2) protein was decreased in LNCaP cells. The transcription factor CDX2 bound to the miR-145-5p promoter region and inhibited its transcription. The transcription start site of miR-145-5p was located at a guanine residue 1,408 bp upstream of the stem-loop sequence. Upon overexpression, miR-145-5p could bind to the 3′-untranslated region of SENP1 to inhibit its translation. Conclusion: These results suggested that CDX2 inhibits the expression of miR-145-5p, thereby relieving the inhibitory effect of miR-145-5p on the translation of SENP1 and affecting the invasion and migration of prostate cancer cells.

microRNAs (miRNAs) are small non‑coding RNAs that regulate gene expression by binding to the untranslated regions (UTRs) of target mRNAs. Bioinformatic software predicted that MYCN, a gene overexpressed in aggressive neuroblastoma cells, is a target gene of miRNA‑202 (miR‑202) and that the promoter region of miR‑202 contains binding sites for the transcription factor E2F1. The aims of this study were to explore the regulation of MYCN expression by miR‑202 in the LAN‑5 human neuroblastoma cell line and to confirm the presence of binding sites for E2F1 in the miR‑202 promoter region. LAN‑5 cells were transfected with a synthetic miR‑202 mimic, an miRNA inhibitor or appropriate control miRNAs. miR‑202 expression levels prior to and following transfection were measured by quantitative polymerase chain reaction (PCR) and MYCN protein expression was measured by western blot analysis. The interaction between miR‑202 and MYCN was examined using a luciferase reporter assay. The transcription start site of miR‑202 was determined by the rapid amplification of 5'cDNA ends (5'RACE) test and a chromatin immunoprecipitation (ChIP) assay was used to confirm binding sites for E2F1 in the miR‑202 promoter region. Overexpression of miR‑202 in LAN‑5 cells specifically inhibited MYCN protein expression. The 5'RACE test showed that the transcription start site of miR‑202 was at a thymidine, 312 bp upstream of the stem‑loop sequence. A ChIP assay demonstrated that E2F1 binds directly to the miR‑202 promoter region. miR‑202 is activated by E2F1 and in turn downregulates MYCN protein expression in the neuroblastoma cell line LAN‑5. Upregulation of miR‑202 may therefore be a novel strategy for neuroblastoma treatment.

Objective: To evaluated the efficacy and safety of noninvasive brain stimulation (NIBS) combined with antidepressants in patients with poststroke depression (PSD).Methods: Seven databases were searched to identify randomized controlled trials of NIBS combined with antidepressants in the treatment of PSD based on the international classification of diseases (ICD-10) criteria and exclusion criteria. The retrieval time was from the database establishment to 31 October 2021. Two researchers independently screened the identified studies through the search strategy, extracted their characteristics, and evaluated the quality of the included literature. Cochrane Collaboration’s tool was used to assess risk of bias. RevMan 5.3 software was applied for meta-analysis.Results: A total of 34 randomized controlled trials were included, involving 2,711 patients with PSD. Meta-analysis showed that the total effective rate was higher in the combined therapy than the antidepressant alone [odds ratio (OR): 4.33; 95% confidence interval (CI): 3.07 to 6.11; p < 0.00001]. The Hamilton depressive scale (HAMD) score was significantly lower in repeated transcranial magnetic stimulation (rTMS) (≤10 Hz) combined with antidepressant than in antidepressant alone [standard mean difference (SMD): −1.44; 95% CI: −1.86 to −1.03; p < 0.00001]. No significant difference was seen in rTMS (>10 Hz) combined with antidepressant versus antidepressant alone (SMD: −4.02; 95% CI: −10.43 to 2.39; p = 0.22). In addition, combination therapy more strongly improved the modified Barthel index (MBI) scale than antidepressants [mean difference (MD): 8.29; 95% CI: 5.23–11.35; p < 0.00001]. Adverse effects were not significantly different between two therapies (OR: 1.33; 95% CI: 0.87 to 2.04; p = 0.18).Conclusion: Low-frequency rTMS (≤10 Hz) combined with antidepressants tends to be more effective than antidepressants alone in patients with PSD, and there are no significant adverse effects. In addition, combined therapy may enhance quality of life after stroke. Combination therapy with high-frequency rTMS (>10 Hz) showed no advantage in treating PSD. The transcranial electrical stimulation (TES) combined with antidepressants might be more effective than antidepressants alone, which are needed to confirm by more clinical trials since the.